UNIVERSITY FARM 
 
RICHTER'S ORGANIC CHEMISTRY 
 
ORGANIC CHEMISTRY 
 
 OR 
 
 CHEMISTRY OF THE CARBON COMPOUNDS 
 
 BY 
 
 VICTOR VON RICHTER 
 
 EDITED EY PROF. R. ANSCHUTZ AND DR H. MEERWEIN 
 
 VOLUME II 
 
 CHEMISTRY OF THE CARBOCYCLIC COMPOUNDS 
 
 TRANSLATED FROM THE I1TH GERMAN EDITION 
 BY 
 
 E. E. FOURNIER D'ALBE, D.Sc., A.R.C.Sc. 
 
 AUTHOR OF "CONTEMPORARY CHEMISTRY," "THE ELECTRON THEORY," ETC. 
 
 
 
 
 LONDON 
 KEGAN PAUL, TRENCH, TRUBNER & CO. LTD. 
 
 PHILADELPHIA : P. BLAKISTON'S SON & CO. 
 1922 
 
PREFACE TO THE ELEVENTH 
 GERMAN EDITION 
 
 THE second volume of the present work was published in its last 
 edition in 1905 by me in collaboration with Professor Georg Schroeter. 
 Dr Schroeter, who had also rendered extremely able assistance in the 
 production of the seventh and succeeding editions, was appointed a 
 year ago to the distinguished position of Professor of Chemistry at the 
 Veterinary College in Berlin. Collaboration in the preparation of the 
 present second volume of the treatise was then undertaken by his 
 successor at the Chemical Institute, Dr Hans Meerwein, Assistant 
 Instructor in Organic Chemistry. 
 
 RICHARD ANSCHUTZ. 
 
 Since the publication of the second volume seven years have 
 elapsed, during the last few of which the book was out of print. In 
 the course of these latter years the amount of new subject-matter has 
 undergone a remarkable increase. Consequently, the present volume, 
 in comparison with the last edition, has had to be enlarged by more 
 than nine sheets, in spite of the adoption of a larger size of page, as 
 otherwise the whole character of the edition would have been altered. 
 
 As in previous editions, a list of the most important interpolations 
 and additions is given below. 
 
 Tri-, tetra-, penta-, hepta-, octo-, and nonocyclic compounds. Special 
 attention is called to the ring expansion by the action of nitric acid 
 on cyclo-alkyl methylamine as a new general reaction. The tetra- 
 methylene group has been supplemented principally by the inclusion 
 of the simplest examples : cyclobutane, cyclobutene, and cyclo- 
 butanone. The simplest saturated, and unsaturated, carbohydrates, 
 with eight-membered carbon rings, are obtained by the transformation 
 of pseudo-pelletierin, and have been very closely examined. By the 
 recognition of the constitution of india-rubber as a polymeric dimethyl, 
 cyclo-octadiene, the group of octocarbocyclic compounds has gained 
 considerably in interest. 
 
 The class of nonocarbocyclic compounds has had to be added. 
 
 Single-nucleus aromatic substances. The historical account of the 
 theory of the aromatic compounds has been supplemented at essential 
 points (p. 28). 
 
 Special attention is directed to the extremely consistent splitting 
 up of benzene and its homologues by the oxidising action of ozone. 
 
 Halogen derivatives of benzene carbohydrates. Recognition of the 
 fact that the capacity for reaction of aromatically combined halogens 
 
vi PREFACE 
 
 can be very considerably increased by the addition of finely divided 
 copper or copper salts, has proved of great practical importance. 
 
 Nitrogenous derivatives of benzene carbohydrates. The preparation 
 of optically active dialkyl anilin oxides is worthy of attention. 
 
 The behaviour of nitro-diphenylamines in the formation of salts has 
 been more closely examined, and more satisfactory reasons have been 
 given for regarding them as pseudo-acids. As regards new investiga- 
 tions on the diazo-amido-compounds, the preparation of diazo-benzene 
 amide is particularly important. New methods of obtaining diazo- 
 amido-compounds have been discovered. The discovery of two 
 isomeric, differently coloured, series of salts is important, as regards 
 the constitution of amido-azo-compounds, and their salts. Attention 
 is directed to the production of tetraphenyl-hydrazin and its interesting 
 resolving reactions ; see also diphenyl-dihydro-phenazin. The process 
 of reaction in the formation of phenyl-hydrazones, by the action of 
 diazo-benzene salts on aliphatic compounds with easily replaceable 
 hydrogen atoms, has been experimentally elucidated in its individual 
 phases. 
 
 The group of aromatic compounds of arsenic has attained greater 
 importance, through the discovery of pharmaceutically valuable 
 substances, such as salvarsan. 
 
 Phenols. The consideration of the nitro-phenols as pseudo-acids 
 has gained in interest by the discovery of a red ester of picric acid. 
 The question of the constitution of the oxy-azo-benzenes has been 
 finally decided in favour of the azo-formula. Reference may also be 
 made to the discovery of cyclic double esters of the phenol-sulpho- 
 acids : sulphonylides. 
 
 Quinones. The discovery of the long- sought o-benzo-quinone 
 should be mentioned in the first place. The nitrogenous derivatives 
 of the quinones have been thoroughly discussed. The investigation 
 of the reactions and constitution of anilin-black by the oxidation of 
 anilin is of the highest importance. Attention may also be called to 
 the remarkable researches regarding the so-called two-nucleus quinones 
 of the diphenyl, naphthalin, and anthracene series. 
 
 The nitrogenous derivatives of the oxy-phenyl-paraffin alcohols have 
 been thoroughly discussed, owing to their marked physiological action. 
 Special attention is directed to the analysis and synthesis of adrenalin 
 
 (P- 370). 
 
 Aromatic aldehydes and ketones. In this group a series of new 
 and, in some cases, easily effected syntheses should be noted. Special 
 attention should be given to the atom displacements in the trans- 
 formation of the aromatic ethylene glycols, the halogen hydrines, and 
 the ethylene oxides. 
 
 Aromatic carbo-acids. Benzoyl nitrate, benzo-nitrosol acid, benzo- 
 nitrol acid, and benzo-nitrile oxide figure as new carboxyl derivatives 
 of benzoic acid. With reference to the constitution of anthranile, the 
 so-called dianthranilides must be mentioned, as the true bimolecular 
 anhydrides of the anthranile acids. Thiosalicylic acid and its progeny 
 have been much used as the basic products for preparing thio- 
 indigo red. 
 
 The discovery of di-iodo-tyrosin in certain species of coral is of 
 physiological importance. 
 
PREFACE vii 
 
 Single-nucleus aromatic substances with unsaturated side chains. 
 The discovery of the tri-morphism of allo-cinnamic acid, whereby the 
 previously vague isometry of the cinnamic acids may be regarded as 
 explained, is of principal interest in this field. 
 
 Hydro-aromatic substances. Inasmuch as by the smooth method 
 of reduction of aromatic compounds, by means of hydrogen and finely 
 divided nickel, the hydro-aromatic substances have become an easily 
 accessible primary material, this field of research has made remarkable 
 progress, mainly by the use of Grignard's reaction. For determina- 
 tions of constitution, especially as regards terpenes, the elegant method 
 of oxidation by means of ozone has proved of great service. For 
 terpene chemistry the synthesis of unsaturated hydrocarbons, with 
 semi-cyclic double linking, is of importance. The tetra- and dihydro- 
 benzenes were subjected to a fresh critical study. Extended synthetic 
 investigations with regard to the cyclo-nitrales have finally led to a 
 synthesis of irone, which, however, is not technically valuable. A 
 curious method for the synthesis of different hydro-aromatic substances 
 was discovered in the action of chloroform and alkali on o- and 
 p-alkaline phenols. The production of the optically active forms of 
 4-methyl-cyclo-hexilidene-acetic acid, in which the asymmetry of the 
 molecule is not caused by the presence of an asymmetric carbon atom, 
 is of technical interest. 
 
 Attention might also be directed to the splitting of cyclic ketones 
 by means of sunlight. 
 
 Terpenes. The exceedingly numerous researches made in the entire 
 field of terpene chemistry have necessitated an almost complete re- 
 working, and a partial re-division, in particular of the di-cyclic terpenes. 
 The olefinic terpene group has been enriched by the discovery of 
 ocimene and nerol. The constitutional determinations of the mono- 
 cyclic terpenes, which may now be regarded as concluded, have been 
 confirmed by numerous syntheses. Thus, dipentene, terpinene, 
 a-phellandrene, sylvestrene, and carvestrene have been obtained in a 
 synthetic manner. A number of analogously composed combinations 
 derived from the terpenes, such as terpinene, terpene, terpinene-cineol, 
 and terpinenol, have ranged themselves alongside of terpin, cineol, and 
 the terpineols. Sabinene and thuyene were associated, by numerous 
 transformations, with terpinene and the terpinenoles. Eucarvone has 
 been examined again, and has been recognised as a heptacarbocyclic 
 combination. The pinene separated from the turpentine oils, has been 
 recognised as a mixture of two linkage-isomeric terpenes, and from these 
 a number of new derived and transformation products are obtained. 
 The transformation of pinene into borneol and isoborneol, or their 
 esters, has been converted into a technically realisable method for the 
 artificial production of camphor from turpentine oil. A fresh and very 
 thorough treatment of camphene has confirmed the Wagner camphene 
 formula ; nevertheless, this has raised doubts as to the unity of this 
 terpene. Bornylene, camphane, isocamphane, and santene were the 
 subjects of new and fruitful researches. A series of articles on the 
 behaviour of borneol and isoborneol towards each other, and towards 
 pinene or camphene - chlorohydrate, appear to prove the stereo- 
 isomerism of these combinations. The constitution of fenchone could 
 be accurately ascertained by a series of splitting reactions. 
 
viii PREFACE 
 
 Phenyl-benzenes and phenylfat carbohydrates. A series of naturally 
 occurring substances have been recognised as oxybenzo-phenones, and 
 oxybenzylidene-acetophenones, which have hitherto been regarded as 
 phenol esters of protocatechu acid and oxy-cinnamic acid. 
 
 Important new observations have been made in favour of regarding 
 the coloured salts of triphenyl-carbinole as quinoid combinations ; 
 see also dibenzylidene-acetone. 
 
 The benzein, rosamin, and phthalein classes have been increased 
 by further research. 
 
 Prominence should be given to diphenylketene, the most easily 
 accessible, and consequently the most thoroughly examined, factor in 
 this class, rich in reactions. 
 
 Amongst the most theoretically important researches which have 
 been made in various directions with excellent results, we may mention 
 those relating to hexaphenyl-ethane, and similar combinations, and 
 their dissociation into the corresponding triaryl-methyls. 
 
 The diphenyl-butane group has been enriched by notable papers 
 relating to diphenyl-butadiene and diphenyl-butenin. 
 
 Condensed nuclei. Notice should be taken of the virtual tautomery 
 of anthranol and anthrones, as well as of anthra-hydrokinone and 
 oxanthrone. The amido-anthrakinones have repeatedly shown them- 
 selves to be excellent intermediaries for the production of new vat dyes, 
 and so have the dianthrakinonyls and the benzo-anthrones. 
 
 Glucosides. There have been new investigations on certain gluco- 
 sides related to amygdalin (p. 719). 
 
 Natural dye-stuffs. Much light has been thrown on the complex 
 
 constitution of cochineal dye. 
 
 
 
 The above brief review, in the course of which we have only been 
 able to refer to some of the most important recent developments, shows 
 that, in the time which has elapsed, notable progress has been made in 
 nearly all classes of carbocyclic compounds. 
 
 RICHARD ANSCHtJTZ. 
 
 HANS MEERWEIN. 
 BONN, October 1912. 
 
CONTENTS 
 
 CARBOCYCLIC COMPOUNDS 
 
 PAGE 
 
 Ring Formation in Cyclo-paraffin Bodies ...... 3 
 
 I.TRI-, TETRA-, PENTA-, HEPTA-, OCTO-, 
 AND NONOCARBOCYCLIC COMPOUNDS . 6 
 
 A. Trimethylene Group. Trimethylene, Trimethylene-carboxylic Acid . 7 
 
 B. Tetramethylene Group. Tetramethylene, Cyclobutene, Cyclobutanine . 10 
 
 C. Pentacarbo cyclic Compounds. Camphor, Pentamethylene, Cyclopentene, 
 
 Cyclopentadiene, Alcohols, Ring Ketones, Adipin Ketones, Diketo- 
 pentamethylene, Aldehydes and Extra-cyclic Ketones, Carboxylic 
 Acids, Alcohol-carboxylic Acids, Keto-carboxylic Acids, Bicyclo- 
 pentane ........... 13 
 
 D. Heptacarbocyclic Compounds. Suberane, Suberene, Cycloheptadiene, 
 
 Tropilidene, Oxy-suberane-carboxylic Acid ..... 22 
 
 E. Octocarbocyclic Compounds. Cyclo-octane, Azelane .... 25 
 
 F. Nonocarbocyclic Compounds ........ 26 
 
 II. HEXACARBOCYCLIC COMPOUNDS . 27 
 
 A. MONONUCLEAR AROMATIC SUBSTANCES OR 
 BENZENE DERIVATIVES 
 
 History. General Survey. Isomerism of Benzene Derivatives. Principles 
 of Location for Benzene Substitution Products. Location of the Di- 
 derivatives. Isomerism of the Poly-substitution Products. Constitu- 
 tion of the Benzene Nucleus. Benzene Ring Formations. Benzene 
 Ring Splittings. Splitting by Feeble Oxidation. Splitting by 
 simultaneous Chlorination and Oxidation. Splitting by Reduction 
 in Alkaline Solutions . . . . . . . . .27 
 
 1. SINGLE-NUCLEUS BENZENE DERIVATIVES : 
 
 Benzol. Coal-tar. Working of Coal-tar for Aromatic Hydrocarbons. 
 Alkyl-benzols. Allylene. Isomerism and Constitution of 
 Alkyl-benzols. Xylol. Ethyl-benzol, Mesitylene, Cymol, 
 Toluol .......... 49 
 
 2. HALOGEN DERIVATIVES OF THE BENZENE HYDROCARBONS : 
 
 A. Halogen Substitution Products of Benzene. Fluoro-benzols, 
 
 Bromo-, Chloro-, and lodo-benzols ..... 60 
 
 B. Halogen Derivatives of the Alkyl-benzols. Benzyl and Benzal Com- 
 
 pounds. Chloro-, Bromo-, lodo-, and Fluoro-toluol . . 64 
 
 3. NITROGEN DERIVATIVES OF BENZENE HYDROCARBONS ... 67 
 
 (1) Nitro-derivatives of Benzene and the Alkyl-benzols. Nitro-benzols, 
 
 Nitro-toluols. Nitro-products of the Alkyl-benzols. Nitro- 
 halogen Derivatives of the Alkyl-benzols .... 68 
 
 (2) Nitroso-derivatives of Benzene and the Alkyl-benzols. Nitroso- 
 
 benzols, Nitroso-toluols ....... 75 
 
 (3) fi-Alphyl- or Aryl-hydroxylamines. Formyl- and Phenyl-hydro- 
 
 xylamines. Chloro- and Nitro-compounds. Nitroso-diphenyl- 
 hydroxylamines . . . . . . . 77 
 
 (4) fi-Alphyl-nitroso-hydroxylamines ...... 79 
 
 (5) Amido-derivatives or Anilines. (a) Primary Phenyl-amines. Their 
 
 Reduction and Exchange Reactions. Their Properties and 
 Transformations, (b) Secondary and Tertiary Phenyl-amines 
 and Phenyl-ammonium Bases. Phenyl-alkylamine. Separa- 
 tion of Primary, Secondary, and Tertiary Bases. Di-alkyl- 
 aniline Oxides. Methyl-anilines. (c) Poly-phenyl-amines. 
 (d) Aniline Derivatives of Inorganic Acids. (e) Carboxylic 
 
x CONTENTS 
 
 PACE 
 
 Derivatives of the Aromatic Primary and Secondary Bases. 
 (/) Phenylated Amidins of Formic Acid and Acetic Acid. 
 Carbylamines, Ureas, and Phenyl-ureas, Thio-ureas, and 
 Hydrazin Derivatives, (g) Phenylated Nitriles and Imides of 
 Carbonic Acid. Phenyl Isocyanate. Phenyl Sulpho-cyanide. 
 Cyanamide Derivatives. Phenyl-amine Derivatives of Oxalic 
 Acid. Anilides of Dicarbpxylic Acid. Anilido-carboxylic 
 Acids. Aniline Substitution Products. Aniline Haloids. 
 Nitranilines. Nitro-diphenyl-amines. (h) Nitroso- derivatives 
 of the Primary, Secondary, and Tertiary Amines ... 79 
 (5) Diamines. Phenylene-diamines. Toluene- and Xylene-di- 
 amines. Condensation of o-Diamines. Differences between 
 o-, m-, and p-Diamines. Triamines and Tetramines . . 113 
 
 (6) Phenyl-nitrosamines. Nitrosanilides. Nitroso-formanilides . 119 
 
 (7) Phenyl-nitr amines. Diazo-benzoic Acids . . . .120 
 
 (8) Diazo-compounds. Aromatic Diazo-derivatives. Diazonium 
 
 Salts. Diazo-perhalides. Iso-diazo-hydrate. Diazo-benzol- 
 sulphonic Acids. Diazo-benzol Cyanide. Chief Decomposi- 
 tions of Diazo-benzol Salts . . . . . .121 
 
 (9) Diazo-amido-compounds . . . . . . .132 
 
 (10) Dis-diazo-amido-compounds. Reactions and Formations. Diazo- 
 amido-compounds from Primary Aromatic Bases. Mixed 
 Fatty-aromatic Compounds. Phenyl- triazones. Re-arrange- 
 ments of Diazo-amido-compounds . . . . .132 
 
 (n) Diazo-oxy-amido-compounds. Diazo-oxy-amido-benzol . . 137 
 
 (12) Diazo-amido-compounds. Diazo-benzol-imides. Their trans- 
 
 formations. Tetrazones . . . . . . .137 
 
 (13) Azoxy-compounds. Their Formation and Behaviour. Azoxy- 
 
 benzol . . . . . . . . . 139 
 
 (14) Azo-compounds. Their Classification, Nomenclature, Formation, 
 
 and Properties. Indifferent Symmetrical Azo-compounds. 
 Azo-benzols and Azo-toluols. Amido-azo-compounds . .140 
 
 (15) Hydrazin Compounds. Hydrazo-compounds. Hydrazo-benzols 
 
 and -toluols. The Benzidin and Semidin Transformations 
 of the Hydrazo-compounds. The Phenyl-hydrazin Group. 
 Phenyl-alkyl-hydrazins. Hetero-ring Formations of Sub- 
 stituted Phenyl-hydrazins. Phenyl-hydrazone and Osazone. 
 Phenyl-hydrazone Transformations. Phenyl-hydrazin Deri- 
 vatives of the Inorganic Acids. Carboxylic Derivatives of 
 Phenyl-hydrazin. Fatty Acid Derivatives. Alcoholic Acid 
 Derivatives. Phenyl-hydrazin Derivatives of Mono-ketonic 
 Carbonic Acid. Dicarboxylic Acids. Olefin- and Oxy- 
 dicarboxylic Acids. Hetero-ring Formation of Phenyl- 
 hydrazin Derivatives of Dicarboxylic Acids. . . .145 
 
 (16) Hydrazins or Amidrazones. Nitrazones. Phenyl-hydrazo- and 
 
 Phenyl - azo - aldoximes. Formazyl Compounds. Phenyl- 
 nitroso-hydrazin. Tetrazones. Hydro-tetrazones . .163 
 
 4. AROMATIC COMPOUNDS OF PHOSPHORUS, ARSENIC, ANTIMONY, BISMUTH, 
 
 BORON, SILICON, AND TIN : 
 Phenyl-phosphene. Phenyl-arsenic Compounds. Phenyl-boron and 
 
 -silicon Compounds . . . . . . . .168 
 
 5. PHENYL METAL DERIVATIVES : 
 
 Magnesium - diphenyl. Aryl - magnesium Haloids. Mercury- 
 
 diphenyls ....... . 171 
 
 6. SULPHONIC ACIDS : 
 
 Formation. Properties and Transformations. Monosulphonic 
 Acids. Benzo-sulphonic Acids. Benzo-sulpho-compounds. 
 Xylol-sulphonic Acids. Poly-sulphonic Acids. Chloro-, 
 Bromo-, lodp-, lodoso-, Nitro-, Nitroso-, and Amido-benzol- 
 sulphonic Acids. Sulphanilic Acid. Amido-azo-benzol Acids . 
 Sulphinic Acids. Sulphones and Sulphoxides . . .172 
 
 7. PHENOLS : 
 
 Monohydric Phenols. Their Formation and Behaviour. Their 
 Colour Reactions, and Nuclear Syntheses. Phenolates. 
 Cresols. Ethyl- and Propyl-phenols. Thymol. Carvacrol. 
 
CONTENTS xi 
 
 PAGE 
 
 Derivatives of Monohydric Phenols. Phenol-alcohol Ethers. 
 Phenoxalkylamines. Phenol Ethers. Acid Esters of Phenol. 
 Phenyl Esters of the Phosphoric Acids. Phenyl Carbonates. 
 Phenol Substitution Products. Phenol Haloids. Mono- and 
 Poly-haloid Phenols. Nitro-phenols. Mono-, Di-, Tri-, and 
 Tetra-nitro-phenols. Picric Acid. Haloid Nitro-phenols. 
 Nitroso - compounds. Nitroso - phenol. Nitroso - cresol. 
 Amido-phenols. Their Condensations. Diamido-phenols. 
 Diazo-phenols. Azoxy-phenols. Azo-phenols. Hydrazo- 
 phenols. Thio-derivatives. Mercaptans. Condensation of 
 o-Amido-thio-phenols. Phenyl Sulphides. Amido-phenyl- 
 Sulphides. Dihydric Phenols. Pyro-catechin. Hetero-ring 
 Formations from Pyro-catechol. Homologous Pyro-catechols. 
 The Resorcin Group. Resorcin. Its Ethers and Esters. 
 Nitro- and Thio-resorcin. Homologous Resorcins. Orcin. 
 Hydroquinone Group. Hydroquinone. Homologous Hydro- 
 quinones. Substituted Hydroquinones. Trihydric Phenols. 
 Pyrogallol. Phloro-glucin. Tetrahydric Phenols. Penta- 
 and Hexahydro-phenols . . . . . . .183 
 
 8. QUINONES : 
 
 Ortho-quinones. Para-quinones. Phenol Addition Products of 
 Quinones. Homologous p-Quinones. Quinone Haloids. Oxy- 
 quinones and Polyquinoyls. Croconic and Leuconic Acid. 
 Nitrogen Derivatives of Quinone. Quinone Dioximes, 
 Imines, and Azines. Indo-phenols. Indo-anilines. Quinone 
 Phenyl-di-imines. Aniline Black. Indamines . . . 224 
 
 9. PHENYL-PARAFFIN ALCOHOLS AND THEIR OXIDATION PRODUCTS . . 239 
 
 (a) MONOHYDRIC PHENYL-PARAFFIN ALCOHOLS AND THEIR OXIDA- 
 TION PRODUCTS : 240 
 
 (1) Monohydric Phenyl-paraffin Alcohols. Benzyl Alcohol. 
 
 Homologous Phenyl-paraffin Alcohols. Derivatives of 
 the Phenyl-paraffin Alcohols. Homologous Phenyl- 
 alkyl Chlorides. Esters of Carboxylic Acid. Nitrogen 
 Derivatives of the Phenyl-paraffin Alcohols. Benzyl- 
 amines. Benzyl-anilines. Benzyl-diazo-compounds, 
 Triazenes, and Azides. Benzyl-hydroxylamines. Sub- 
 stituted Benzyl Alcohols. Formation of Hetero-rings 
 from Derivatives of o-Amido-benzyl Alcohol . . 240 
 
 (2) Aromatic Monaldehydes. Benzaldoximes. Pyrones. 
 
 Benzaldehyde. Homologous Benzaldehydes. Deri- 
 vatives of Benzaldehyde. Benzaldehyde Haloids. 
 Nitro-, Nitroso-, Hydroxylamino-, Azoxy-, Azo-, and 
 Amido-benzaldehydes. Hetero-ring Formations of 
 Benzaldehyde ....... 252 
 
 (3) Aromatic Monoketones. Aceto - phenone. Its Homo- 
 
 logues. Homo-benzolated Paraffins. Nitro-aceto- 
 phenones. Amido-aceto-phenones. Hetero-ring For- 
 mation of the Aromatic o-Amido-ketones . . . 264 
 
 (4) Aromatic Monocarboxylic Acids. Their Formation. Oxi- 
 
 dation with Chromic and Nitric Acids. Nuclear 
 Syntheses and Reactions. Benzoic Acid. Its Homo- 
 logues. Alkyl-benzoic Acids. Ethyl-benzoic Acids. 
 Propyl-benzoic Acids. Phenyl-fatty Acids. Hydra- 
 tropic Acid ........ 269 
 
 (6) DERIVATIVES OF THE AROMATIC MONOCARBOXYLIC ACIDS: 
 
 (1) Esters of the Monobasic Aromatic Acids .... 277 
 
 (2) Aromatic Acid Haloids. Benzoyl Chloride, Bromide, and 
 
 Nitrate 278 
 
 (3) Acid Anhydrides. Benzoic and Aceto-benzoic Anhydrides 279 
 
 (4) Acid Peroxides . . . . . . . .280 
 
 (5) Thio-acids and Bi-thio-acids . . . . . .280 
 
 (6) Acid Amides. Benzamide. Benzanilide. Hippuric Acid. 
 
 Its Salts, Esters, and Nitriles 280 
 
 (7) Acid Hydrazides. Benzoyl-hydrazin .... 283 
 
 (8) Acidyl-azides. Benzoyl-azide. Hippurazide . . . 284 
 
xii CONTENTS 
 
 PAGE 
 
 (9) Nitrites of the Aromatic Monocarboxylic Acids, Benzo- 
 nitrile. Alphyl Cyanides. Nitriles of the Phenyl-fatty 
 Acids. Benzyl Cyanide ...... 285 
 
 (10) Amido-haloids ........ 287 
 
 (n) Imido-chlorides ........ 287 
 
 (12) Phenyl-hydrazide Imido-chlorides . . . . .287 
 
 (13) Imido-ethers of the Aromatic Acids .... 288 
 
 (14) Thiamides of the Aromatic Acids. Thio-benzamide. 
 
 Selenium-benzamide . . . . . .288 
 
 (15) Imido-thio-ethers of the Aromatic Carboxylic Acids . . 289 
 
 (16) Amidines of the Aromatic Carboxylic Acids. Benzamidine. 
 
 Phenyl-benzamidine . . . . . .289 
 
 (17) Dioxy-tetrazotic Acids ....... 290 
 
 (18) Hydrazidins or Amidrazones. Benzenyl-hydrazidin . . 291 
 
 (19) Nitrazones, Nitrosazones, and Phenyl-azoximes . . 291 
 
 (20) Formazyl Derivatives. Formazyl- and Guanazyl-benzol . 292 
 
 (21) Hydroxamic Acids, their Ethers and Esters. Benzo-hydro- 
 
 xamic Acid. Tribenzoyl-hydroxylamme . . . 293 
 
 (22) Haloids of Benzo-hydroxamic Acid .... 294 
 
 (23) Benzo-nitrolic Acid ....... 294 
 
 (24) Benzo-nitrosolic Acid ....... 295 
 
 (25) Nitrile Oxides . . .- . . . . . 295 
 
 (26) Amidoximes. Benzenyl-amidoxime .... 295 
 
 (27) Hydrazidoximes . . . . . . . .296 
 
 (28) Hydroxamoximes . . . . . . .297 
 
 (29) Ethyl-orthobenzoic Esters . . . . . .297 
 
 (30) Benzo-trichlorides and -trifluorides ..... 297 
 
 (31) Orthobenzoic Acid Piperidide. ..... 297 
 
 (c) SUBSTITUTED AROMATIC MONOCARBOXYLIC ACIDS : 
 
 (1) Halogen Benzole Acids . . . . . .297 
 
 (2) lodoso- and lodo-benzoic Acids . . . . .298 
 
 (3) Nitro-monocarboxylic Acids. Nitro-benzoic Acids. Nitro- 
 
 haloid and Nitro-phenyl-benzoic Acids . . .298 
 
 (4) Nitroso-monocarboxylic Acids. Nitroso-benzoic Acid . 300 
 
 (5) Hydroxylamino-carboxylic Acids ..... 300 
 
 (6) Aromatic Amido-monocarboxylic Acids. Anthranilic Acid. 
 
 Anthranile. Acetyl-anthranile. Dimolecular Anhy- 
 drides of Anthranilic Acid. Kynuric Acid. Di- 
 cyanamino - benzoyl. Methyl - anthranilic Acid. 
 Hetero-ring Formations of Anthranilic Acid. Arnido- 
 benzoic Acids. Amido-phenyl-fatty Acids. Atroxindol 301 
 
 (7) Diazo-benzoic Acids . . . . . . .311 
 
 (8) Diazo-amido-benzoic Acids . . . . . .311 
 
 (9) Diazo-imido-benzoic Acids . . . . . .311 
 
 (10) Azoxy-benzoic Acids . . . . . . .311 
 
 (u) Azo-benzoic Acids . . . . . . .311 
 
 (12) Hydrazin-benzoic Acids ...... 312 
 
 (13) Phosphine-benzoic Acids . . . . . .312 
 
 (14) Sulpho-benzoic Acids. Saccharin . . . . .312 
 
 (d) MONOHYDRIC OXY-PHENYL-PARAFFIN ALCOHOLS AND THEIR 
 
 OXIDATION PRODUCTS : 
 
 (1) Monohydric Oxy-phenyl-paraffin Alcohols, or Phenyl 
 
 Alcohols. Saligenin. Anisyl Alcohol. Pseudo-phenol 
 Haloids. Methylene-quinones. Quinols . . .314 
 
 (2) Aromatic Oxy '-mono-aldehydes, Phenol-aldehydes. Salicylic 
 
 Aldehyde. Anisaldoxime. Homologous Monoxy- 
 benzaldehydes. Proto-catechuic Aldehyde. Vanillin. 
 Piperonal. Tri- and Tetra-oxy-benzaldehydes . .321 
 
 (3) Phenol Ketones ........ 325 
 
 (4) Phenol-monocarboxylic Acids. Salicylic Acid. Sali- 
 
 cylates. Anisic Acid. Oxy-toluic and Cresotinic 
 Acids. Oxy-mesitylenic Acids. Phloretic Acid. 
 Phloretin. Vanillic Acid. Luteolin. Catechin. 
 Gentisinic, Orsellinic, and Gallic Acids. Tannin and 
 Tannic Acids ........ 327 
 
CONTENTS xiii 
 
 (e) POLYHYDRIC AROMATIC ALCOHOLS IN WHICH ONLY ONE HYDROXYL 
 IS PRESENT IN EACH SlDE CHAIN, AND THEIR OXIDATION 
 
 PRODUCTS : PAGE 
 
 (1) Di- and Trihydric Aromatic Alcohols. Phthalyl and 
 
 Xylylene Alcohols . -344 
 
 (2) Aldehyde Alcohols ....... 345 
 
 (3) Aromatic Dialdehydes . . . 346 
 
 (4) Di- and Triketones ... ... 347 
 
 (5) Alcohol-carboxylic Acids. Phthalide. Meconin . . 347 
 
 (6) Aldehyde Acids. Phthal-aldehyde Acids. Opianic Acid. 350 
 
 (7) Ketone-carboxylic Acids . . . . . -353 
 
 (8) Dicarboxylic Acids. Phthalic Acids and Chlorides. 
 
 Phthalylene tetrachlorides. Phthalimide. Iso- 
 phthalic Acid. Uvitinic Acid. Terephthalic Acid. 
 Aromatic Dicarboxylic Acids with one molecule of 
 Carboxyl in the Nucleus and in the Side Chain. Homo- 
 phthalimide. Aromatic Dicarboxylic Acids having 
 both Carboxyls in different Side Groups . . . 354 
 
 (9) Aldehydo-dicarboxylic Acids ..... 364 
 (10) Tricarboxylic Acids. Trimellitic and Hemi-mellitic Acids. 
 
 Trimesic Acid ....... 364 
 
 (n) Aromatic Tetracarboxylic Acids. Pyro-mellitic Acid. 
 
 Prehnitic and Mellophanic Acids .... 365 
 
 ) Aromatic Pentacarboxy lie Acid . . . 365 
 
 (13) Aromatic Hexacarboxylic Acid. Mellitic and Euchronic 
 
 Acids ......... 366 
 
 (/) AROMATIC POLY ALCOHOLS CONTAINING MORE THAN ONE HYDROXYL 
 GROUP IN THE SAME SlDE CHAIN, AND THEIR OXIDATION 
 PRODUCTS : 
 
 (1) Phenyl-glycols and Phenyl-glycerin. Stycerine. Haloid 
 
 Esters of the Phenyl-glycols. Dihaloids. Ephedrin. 
 Adrenalin . ..... 367 
 
 (2) Phenyl-alcohol Aldehydes. Phenyl-tetrose . . . 370 
 
 (3) Phenyl Ketols. Aceto-phenone Alcohol. Amido-aceto- 
 
 phenone ........ 371 
 
 (4) Phenyl- aldehyde Ketones. Phenyl-glyoxal . . . 373 
 
 (5) Phenyl-paraffin Diketones. Benzoyl-acetone. Tri- and 
 
 Tetraketones . . . . . . . .374 
 
 (6) Phenyl-paraffin Alcohol Acids. Monoxy-alcohol Acids. 
 
 Mandelic Acids. Dioxindol. Atro-lactonic Acid. 
 Tropic Acid. Phenyl-alanin. Tyrosin. Dioxy- 
 alcohol Acids. Styceric Acid. Trioxy-alcohol Acids. 376 
 
 (7) Phenyl-paraffin-aldehyde-carboxylic Acids . . . 386 
 
 (8) Phenyl - paraffin - ketone - carboxylic A cids. Ketone - car- 
 
 boxylic Acids. Phenyl - glyoxylic Acid. Isatin. 
 Anthroxanic Acid. Cumarandione. Thio-isatin. 
 Homologous Phenyl-glycol Acids. Phenyl-paraffin 
 j3-ketone-carboxylic Acids. Benzoyl-acetic Acid . 387 
 
 (9) Phenyl-alcohol-ketone-carboxylic Acids .... 394 
 (10) Diketone-carboxylic Acids. Quinisatin. Benzoyl-pyro- 
 
 racemic Acid . . . . . . . 395 
 
 (n) Phenyl-paraffin-dicarboxylic Acids. Phenyl-malonic Acid. 
 
 Phenyl- and Benzyl-succinic Acids .... 396 
 
 (12) Phenyl-alcohol-dicarboxylic Acids. Phenyl- and Benzyl- 
 
 malic Acids ........ 397 
 
 (13) Phenyl-ketone-dicarboxylic Acids. Benzoyl-malonic Ester 399 
 
 (14) Phenyl-oxy-ketone-dicarboxylic Acids .... 400 
 
 (15) Phenyl-paraffin-tricarboxylic Acids .... 400 
 
 (16) Phenyl- keto-tricarboxy lie Acids ..... 400 
 
 (17) Polyketo-poly carboxylic Acids ..... 400 
 
 (18) Phenylene-oxy-dicarboxylic Acids. Carbo-mandelic Acid 
 
 (19 
 20 
 
 21 
 
 Acetonyl-phthalide 
 Phenylene-ketone-dicarboxylic Acids 
 Tri- and Tetracarboxylic Acids 
 Oxy-tri-, -tetra-, and -penta-carboxylic Acids 
 
 (22) Ketone-tricarboxylic Acids 
 
 401 
 402 
 402 
 403 
 403 
 
xiv CONTENTS 
 
 (g) MONONUCLEAR AROMATIC SUBSTANCES WITH UNSATURATED 
 
 SIDE CHAINS : PAGE 
 
 la. Olefin-benzenes. Styrol ...... 403 
 
 16. Acetylene Benzenes. Phenyl-acetylene . .407 
 
 Ic. Diolefin-benzols . . . . . . .408 
 
 Id. Olefin-acetylene-benzols ...... 408 
 
 Ila. Ole fin-phenols. (A) Olefin-monoxy-benzols, Vinyl-phenol, 
 Chavicol, Anethol. (B) Olefin-dioxy-benzols, Eugenol, 
 Safrol. (C) Olefin-trioxy-benzols, Asarone, Elemicin, 
 Myristicin. (D) Olefin-tetraoxy-benzols, Apiol . . 408 
 116. Acetyl-anisol and Phenetol . . . . . . 413 
 
 Ilia. Phenyl-olefin Alcohols and their Oxidation Products. (la) 
 Phenyl-olefin Alcohols, Styrone. (16) Oxy-phenyl- 
 olefin Alcohols, Coniferyl Alcohol, (ic) Phenyl-acety- 
 lene Alcohols. (2 a) Phenyl-olefin Alcohols, Cinnamic 
 Aldehyde. (26) Oxy - phenyl - olefin Aldehydes. (3) 
 Phenyl-diolefin Aldehydes. (4a) Phenyl-olefin Ketones. 
 (5) Phenyl-acetylene Aldehydes. (6) Phenyl-acetylene 
 Ketones. (7) Phenyl-diolefin Ketones. (8) Phenyl - 
 olefin - carboxylic Acids, Cinnamic Acid and its Deri- 
 vatives, Haloid Cinnamic Acids, Nitro-cinnamic Acids, 
 Amido - cinnamic Acids, Hydrazin - cinnamic Acids, 
 Sulpho-cinnamic Acids, Homologous Cinnamic Acids, 
 Atropic Acid ...... -413 
 
 Illb. Oxy-phenyl-olefin-carboxylic Acids. (A) Monoxy-phenyl- 
 olefin-carboxylic Acids, Cumarin, Cumaroxime. (B) 
 Dioxy-phenyl-olefin-carboxylic Acids, Caffeic Acid, 
 Umbelliferone. (C) Trioxy-cinnamic Acids. (D) Tetra- 
 oxy-cinnamic Acids, Fraxetin. (E) Phenyl-acetylene- 
 carboxylic Acids. (F) Phenyl-diolefin-carboxylic Acids, 
 Piperic Acid ..... . 426 
 
 IV. Compounds which may be considered as Oxidation Pro- 
 ducts of Mononuclear Aromatic Poly alcohols with Un- 
 saturated Side Chains. (i) Phenylene - oxy - olefin - 
 carboxylic Acids, Iso-cumarin, Iso-carbo-styril, Ber- 
 gaptene. (2) Phenylene - aldehyde - carboxylic Acids. 
 (3) Phenylene-dicarboxylic Acids. (4) Phenyl-olefin- 
 ketols. (5)Phenyl-oxy-olefin-carboxylic Acids. (6) 
 Phenyl-oxy-diolefin-carboxylic Acids. (7) Phenyl- 
 dioxy-olefin-carboxylic Acids. (8) Phenyl-olefin-a- 
 keto- carboxylic Acids. (9) Phenyl-diolefin-a-keto-car- 
 boxylic Acids. (10) Phenyl-olefin- /?-ketone-carboxylic 
 Acids. (n) Phenyl-olefin- and -diolefin-y-ketone-car- 
 boxylic Acids. (12) Phenyl-olefin-dicarboxylic Acids. 
 
 (13) Phenyl-diolefin-dicarboxylic Acids, Benzal-malonic 
 Acid, Cyano-cinnamic Acid, Cinnamylidene - malonic 
 Acid, Phenyl-malei'c Acid, Cinnamenyl-glutaric Acid. 
 
 (14) Phenyl-olefin-tricarboxylic Acids. (15) Phenyl- 
 oxy-olefin-dicarboxylic Acids. (16) Phenylene-oxy- 
 olefm-dicarboxylic Acids. (17) Phenylene-oxy-olefin- 
 tricarboxylic Acids . . . . . . .434 
 
 B. HYDRO-AROMATIC SUBSTANCES WITH SINGLE 
 
 NUCLEUS, HYDRO-BENZOL DERIVATIVES 
 i. Hydro-aromatic Hydrocarbons ........ 443 
 
 ia. Cyclo-hexanes, Hexahydro-benzols, Naphthenes. Halogen Substitution 
 
 Products of the Hexahydro-benzols .... . 444 
 
 i b. Cyclo-hexenes, Tetrahydro-benzols, Naphthylenes. Methyl- and Dimethyl- 
 
 cyclo-hexene . . . . . . . ... 447 
 
 ic. Dihydro-benzols, Cyclo-hexadienes ...... 
 
 2a. Ring Alcohols of the Hydro-aromatic Carbons. Cyclo-hexanol. Quinite 
 Quercite. Inosite. Phenose ...... 
 
 26. Ring Alcohols of Tetrahydro -benzol ...... 
 
 2c. Extra-cyclic Hydro-aromatic Alcohols ..... 
 
 2d. Sulphur Derivatives of Hydro-aromatic Alcohols. 
 
 $a. Ring Amines of Hydro-aromatic Hydrocarbons. Amido-cyclo-hexane 
 
 449 
 
 454 
 454 
 455 
 455 
 
CONTENTS xv 
 
 PAGE 
 
 36. Extra-cyclic Hydro-aromatic Amines . ... 456 
 
 4. Ring-ketones of the Hydro-aromatic Hydrocarbons. Ring-ketones of 
 
 Hexahydro-benzol. Ring-ketols. Dihydro-resorcin. Tetrahydro- 
 quinone. Ring-ketones. Tetrahydro-benzol. Ring-ketones of the 
 Dihydro-benzols ......... 456 
 
 5. Hydro-aromatic Aldehydes. Cyclo-citral ...... 466 
 
 6. Extra-cyclic Hydro -aromatic Ketones. Irone. lonone . . . 467 
 
 7. Hydro-aromatic Carboxylic Acids. (i) Hydro-aromatic monocarboxylic 
 
 Acids, Hexahydro-benzoic Acids, Tetrahydro-benzoic Acids, Di- 
 hydro-benzoic Acids, Aliphatic Acids, Phenyl-fatty Acids, Hexa- 
 hydro-oxy-benzoic Acids, Quinic Acid, Shikimic Acid, Keto-hydro- 
 monocarboxylic Acid. (2) Hydro-aromatic Dicarboxylic Acids. 
 Hexahydro-dicarboxylic Acids, Hexahydro-terephthalic Acids. Tetra- 
 hydro-dicarboxylic Acids, Dihydro-dicarboxylic Acids, Oxy- and 
 Keto-hydro-benzol-dicarboxylic Acids, Succino-succinic Acid. (3) 
 Hydro-benzol-tricarboxylic Acids. (4) Hydro-benzol-tetracarboxylic 
 Acid ........... 469 
 
 TERPENES ........ ... 484 
 
 A. Olefinic Terpene Group. (i) Olefinic Terpenes, Myrcene, Ocimene, 
 
 Isoprene. (2) Olefinic Terpene Alcohols, Geraniol, Nerol, 
 Linalool. (3) Olefinic Terpene Aldehydes, Citronellal, Citral. 
 (4) Olefinic Terpene Acids, Geranic Acid . . . .487 
 
 B. Monocyclic Terpene or Menthane Group. (i) Limonene and 
 
 Dipentene Group, Terpinolene, Terpinene, Phellandrene. (2) 
 Alcohols of the Monocyclic Terpene or Menthane Group, Mon- 
 acid Menthane Alcohols, Secondary Menthols, Tertiary 
 Menthols, Diacid Alcohols, Terpin, Cineol, Terra-acid Methane 
 Alcohols, Terpineol-menthadiene Alcohols. (3) Bases of the 
 Monocyclic Terpene or Menthane Group. (4) Ring-ketones 
 of the Monocyclic Terpene or Menthane Group, Menthone, 
 Carvenone, Pulegon, Carvone . . . . . .491 
 
 C. Dicyclic Terpene Group : 
 
 I. Sabinane or Tanacetane Group. Thujene. Sabinane . 510 
 
 II. Carane Group. Carone. Eucarvone . . . -514 
 
 III. Pinane Group. Pinene. Turpentine Oil. Terebinic Acid. 
 
 Myrtenol. Pinol . . . . . -515 
 
 IV. Camphane Group. Camphene. Bornylene. Fenchene. 
 
 Monacid Alcohols. Santene. Borneol. Iso-borneol. 
 Amines. Ketones. Camphor. Campholic Acid. 
 Azo-camphor. Camphenone. Camphanic Acid. 
 Lauronilic Acid. Apo-camphoric Acid. Fenchone . 522 
 
 D. Sesqui-terpene and Poly-terpene Group. Cadinene. Santalol . 546 
 Resins. Caoutchouc ........ 548 
 
 C. AROMATIC HYDROCARBONS CONTAINING 
 SEVERAL NUCLEI 
 
 A. PHENYL-BENZOLS AND POLYPHENYL-FATTY HYDROCARBONS . . 549 
 I. Phenyl-benzol Group. Diphenyl Group. Benzidin. Benzidin 
 Dyes. Oxy-, Monoxy-, and Dioxy-biphenyls. Quinones of 
 the Diphenyl Series. Ccerulignone. Diphenic Acid. Diphenyl- 
 benzol. Tri- and Tetra-phenyl-benzol .... 550 
 
 II. Benzyl-benzol Group. (i) Hydrocarbons, Diphenyl-methanes. 
 (2) Alcohols, Benzo-hydrols. (3) Ketones, Benzo-phenones, 
 Halogen Derivatives, Phenyl-anthranile, Diamido-benzo- 
 phenones, Oxy-benzo-phenones, Cotoin. (4) Carboxylic Acids 
 of the Diphenyl-methane Group, Diphenyl-methane-carboxylic 
 .Acids, Benzo-hydrol-carboxylic Acids, Benzo-phenone-car- 
 boxylic Acids ......... 562 
 
 III. Triphenyl-methane Group. (i) Hydrocarbons, Triphenyl-methane, 
 Nitro- substitution Products. (2) Carbinols, Fuchsine, 
 Rosanilin, Methyl-violet, Phenylated Rosanilins. (3) Phenol 
 Derivatives, Monoxy- triphenyl-methanes . . . -576 
 IIlA. Phenyl Derivatives of Triphenyl-carbinol . Triphenyl-carbinols, 
 hydroxylated in a Benzene Nucleus. Benzems. Rosamines. 
 Aurins and Rosolic Acids. Eupittonic Acid. Triphenyl- 
 
xvi CONTENTS 
 
 PAGE 
 
 methane-carboxylic Acid. Carboxyl Derivatives of Triphenyl- 
 carbinol Phthalides. Carboxyl Derivatives of the Oxy- 
 triphenyl-carbinols. Phthaleins. Fluorane. Phloxin. 
 
 Rhodamins ......... 590 
 
 IIlB. Phenyl-bis-diphenyl-methane ....... 602 
 
 IIIc. Tetraphenyl-methane ........ 602 
 
 IV. Homologous Di- and Poly-phenyl-paraffins. (a) Gem-diphenyl- 
 paraffins and their Derivatives, Diphenyl- ethane, Diphenyl- 
 ketene, Benzilic Acid, Triphenyl- acetic Acid. (6) Syrn. 
 Diphenyl-ethane Group, Dibenzyl, Stilbene, Tolane, Alcohol 
 and Ketone Derivatives of Dibenzyl, Benzoin, Benzile, Alcohol 
 Derivatives of Stilbene, Carboxylic Acids of the Dibenzyl 
 Group, Dibenzyl-carboxylic Acid, (c) Tri-, Tetra-, Penta-, and 
 Hexaphenyl Group, Benzo-pinacone, Hexaphenyl-ethane. 
 (d) Diphenyl-propane Group, Dibenzyl-ketone, Dypnone. 
 Dibenzol-methane-carboxylic Acids. (e) Diphenyl-butane 
 Group, Diphenacyl, Bidesyl, Diphenyl-tetra-ketone, Carboxylic 
 Acids, Vulpic Acid. (/) Diphenyl-pentane Group, Di- 
 benzylidene-acetone, Benzamarone-carboxyl Derivatives, (g) 
 Diphenyl-hexene Group, and Higher Homologues . . . 603 
 
 B. CONDENSED NUCLEI ......... 640 
 
 1. Indene and Hydrindene Group. Indene and its derivatives. 
 
 Hydrindene. Diketo-hydrindene. Indacene . . . 643 
 
 2. Naphthalene Group. Constitution. Isomerisms. Ring Forma- 
 
 tions. Decompositions. Homologues .... 650 
 
 (i) Halogen Naphthalenes. (2) Nitro-naphthalenes. (3) 
 Nitroso-naphthalenes. (4) Amido-naphthalenes, 
 Naphthalamines, Naphthylene - diamines. (5) 
 Diazo- and Azo-compounds. (6) Hydrazin Com- 
 pounds. (7) Sulphonic Acids. (8) Naphthalene- 
 sulphonic Acids. (9) Naphthols, Nitro-, Amido-, 
 and Azo-naphthols, Naphthol-sulphonic Acids, 
 Naphtho-sultone, Thio-naphthols. (10) Naphtho- 
 quinones, Juglone, Nitrogen Derivatives of the 
 Naphtho-quinones . . . . . .658 
 
 (n) Alcohols of the Naphthalene Series and their Oxidation 
 Products. (A) Alcohols. (B) Aldehydes and 
 Ketones. (C) Naphthalene-monocarboxylic Acids. 
 (D) Naphthalene Di- and Poly-carboxylic Acids . 676 
 
 (12) Di- and Trinaphthyl-methane Derivatives . . . 681 
 
 (13) Acenaphthene ....... 682 
 
 (14) Hydro-naphthalene Derivatives. (A) Dihydro-deri- 
 
 vatives. (B) Tetrahydro-derivatives. (C) Hexa-, 
 Octo-, Deca-, and Dodeca-hydro-naphthalenes . 683 
 
 3. Phenanthrene Group. Halogen Nitro-, Oxy-, and Amido-Phen- 
 
 anthrenes. Carboxylic Acids. Hydro - phenanthrenes. 
 Betene. Chrysene. Picene. Pyrene. Triphenylene . . 687 
 
 4. Fluorene Group. Fluorene. Retene, Chrysene, and Picene. 
 
 Fluorene. Phenyl-fluorene. Diphenylene-ketone. Fluor- 
 enone. Fluoranthene ....... 695 
 
 5. Anthracene Group. Anthracene. Alkylic Anthracenes. Sub- 
 
 stituted Anthracenes. Oxy-anthracenes. Anthranol. 
 Anthrone. Anthra-hydroquinone. Oxanthrone. Carboxylic 
 Acids. Hydro-anthracene. Dihydro-anthranol. Anthra- 
 quinone. Alizarin. Purpurin. Emodin. Dianthraquinoyl. 
 Pyran throne. Benzanthrone . . . . . .710 
 
 6. Glycosides or Glucosides and Pentosides. Sinigrin. Sinalbin. 
 
 Arbutin. Salicin. Populin. Gem. Gaultherin. Coni- 
 ferin. Syringin. Phlorizin. /Esculin. Daphnin. Fraxin. 
 Indin. Saponarin. Digitalin. Saponin. Convolvulin. 
 Jalapin. Polygonin. Amygdalin. Naringin. Hesperidin. 
 Quercitrin. Frangulin. Aloin . . . . . .719 
 
 7. Bitter Principles. Cantharidin. Anemonin. Picro-toxin. 
 
 Picrotin. Santonin. Artemisin ..... 724 
 
 8. Natural Dyes. Brasilin. Haematoxylin. Carthamin. Curcumin. 
 
 Lichen Dyes. Carminic Acid. Kermessic Acid . . . 725 
 
A TEXT-BOOK 
 
 OF 
 
 ORGANIC CHEMISTRY 
 
 II. CARBOCYCLIC COMPOUNDS 
 
 THE methane derivatives, or acyclic carbon compounds, with open 
 carbon chains, dealt with in the first volume of this work, are here 
 followed by organic compounds with closed carbon chains, or carbon 
 rings, and these compounds I call by the name of Carbocyclic Com- 
 pounds. In contrast with these we have, e.g., the azocyclic compounds 
 with a ring consisting only of nitrogen atoms, such as nitrogen hydride, 
 and its derivatives. The carbocyclic compounds are also called isocyclic 
 compounds, but the latter expression is too comprehensive, since it 
 denotes compounds containing a ring consisting of a number of atoms, 
 of any element. In contradistinction to isocyclic compounds we have 
 the heterocyclic compounds, in which the atoms of several different 
 elements take part in the formation of the ring. 
 
 The fundamental carbocyclic hydrocarbons are those with a carbon 
 ring consisting of from three to nine methylene groups. They are 
 isomeric with the olefins, with an equal number of carbon atoms. 
 They are designated either as polymethylenes, in accordance with the 
 number of methylene groups which they contain ; or by prefixing an 
 " R " or " R-" to the names of the normal olefins with which they 
 are isomeric (" ring olefins ") ; or, according to the Geneva resolu- 
 tions, by the names of the normal paraffins containing an equal number 
 of carbon atoms with the word " cyclo-" prefixed (cyclo-paraffins). 
 The first and third of these designations are to be preferred. 
 
 /-TT . 
 
 Trimethylene [Cyclopropane] 2 ;CH 2 
 
 Crl 2 / 
 
 /"* TT f"*TT 
 
 Tetramethylene [Cyclobutane] 
 
 C1 2 C.H 2 
 
 /-"TT _ C~H \. 
 
 Pentamethylene [Cyclopentane] f 2 >CH 2 
 
 CH 2 CH 2 / 
 
 Hexamethylene [Cyclohexane] cHCUCll 
 Heptamethylene [Cycloheptane] 
 Octomethylene [Cyclooctane] 
 Nonomethylene [Cyclononane] 
 
 VOL. II. 
 
2 ORGANIC CHEMISTRY 
 
 Hexamethylene is also called hexahydrobenzol, and heptamethylene, 
 suberane. For the nomenclature of ring substances see also B. 29, 587. 
 
 As the paraffins are followed by olefins and diolefins, so the cyclo- 
 paraffins are followed by cyclo-olefin, cyclo-diolefin, and cyclo- 
 triolefin. 
 
 Among the carbocyclic structures a special significance attaches to 
 benzol (benzene), the fundamental hydrocarbon of the so-called 
 aromatic substances or benzol derivatives, the most numerous class 
 of organic compounds. If, in accordance with A. Kekule, we assume 
 in benzol a ring of six carbon atoms linked together in alternate single 
 and double linking an assumption which the author prefers benzol 
 is a cyclotriolefin : 
 
 Benzol [Cyclohexatri6n] C 
 
 \CH =CH 
 
 By the addition of hydrogen it is possible to convert benzol into 
 hexahydrobenzol, hexamethylene, and cyclo-hexane. A constantly 
 increasing number of transformation products of aromatic compounds 
 are becoming known, which can be referred to dihydro- or tetrahydro- 
 benzol (cyclo-hexadiene and cyclo-hexene), and which, together with 
 the hexamethylene or hexahydrobenzol derivatives, are termed " hydro- 
 aromatic compounds." To these belong many natural products, 
 especially those of the terpene and camphor series. If this 
 system were rigidly followed, every cyclo-paraffin system would be 
 associated with the corresponding cyclo-olefin system having the same 
 number of carbon atoms. But the treatment of the hydro-aromatic 
 substances presupposes a knowledge of the aromatic substances, to 
 such an extent that it is better to deal first with the latter. We there- 
 fore treat first of the tri-, tetra-, penta-, hepta-, octo-, and nono- 
 carbocyclic compounds, and afterwards of the hexacarbocyclic 
 compounds. 
 
 In many ways the aromatic substances show a peculiar behaviour, 
 different from that of the aliphatic compounds. But the hydro- 
 aromatic compounds, as well as the other known polycarbocyclic 
 compounds, approach in their chemical properties the saturated 
 aliphatic substances, or the unsaturated ones, if there are any double- 
 linked pairs of carbon atoms in the ring. These compounds are there- 
 fore called aliphatic cyclic, or alicyclic saturated, and unsaturated, 
 compounds, to distinguish them from the aromatic compounds 
 (B. 22, 769). 
 
 The study of the carbocyclic compounds has shown that the tri- 
 and tetramethylene ring is more easily split than the more stable 
 pentamethylene or hexamethylene ring, while hepta- and octomethy- 
 lene rings are formed with greater difficulty, and can usually be easily 
 transformed into rings of a smaller number of carbon atoms. 
 
 We have met similar phenomena in the formation of some hetero- 
 cyclic derivatives of aliphatic substances, e.g. the lactones, lactames, 
 and dicarboxylic anhydrides (Vol. I.). In the case of the oxy-acids we 
 indicated a scheme of the space-configuration of carbon chains, 
 designed to explain the rare formation of a- and j3-lactones, in com- 
 parison with the ease with which y- and 8-lactones are produced. An 
 attempt at explaining the different stabilities of the tri-, tetra-, penta-, 
 
METHODS OF RING FORMATION 3 
 
 and hexamethylene rings is made in the tension theory of A. v. 
 Baeyer (B. 18, 2278; 23, 1275). This theory proceeds from the 
 following assumption : " The four valencies of the carbon atom act 
 in directions joining the centre of a sphere with the corners of an 
 inscribed regular tetrahedron, and therefore form angles of 109 28' 
 with each other." These four lines are called axes. 
 
 "The direction of attraction can undergo a deflection, but this is 
 accompanied by a tension, increasing with the amount of the latter." 
 The assumption of valency forces acting at an angle is excluded, the 
 amount of deflection being proportional to the tension. " In ethylene 
 the direction of attraction is equally deflected, for both valencies of 
 each carbon atom, until the directions have become parallel. In 
 ethylene the angle of deflection is (109 28') =54 44'. In trimethy- 
 lene, which may be figured as an equilateral triangle, the angle between 
 the axes must be 60, and the deflection of each must be 4(109 28' 60) 
 
 =24 44'." 
 
 In the same way we obtain the following deflections : 
 
 Tetramethylene 1(109 28' 9) = 9 44' 
 Pentamethylene ((109 28' 108) = o 44' 
 Hexamethylene {(109 28' 120) =5 16' 
 Heptamethylene |(iO9 28' 128 34') = 9 33' 
 Octomethylene (109 28' 135) =12 51' 
 Nonomethylene (109 28' 140) =15 16' 
 
 This supposes, of course, that the carbon atoms all lie in the same 
 plane, viz. the plane of the ring. 
 
 In dimethylene or ethylene the greatest deflection of the direction 
 of action of both valencies has taken place. It has the greatest tension 
 and is the loosest ring, which is easily split up by chlorine, bromine, 
 hydrobromic acid, and iodine. Trimethylene reacts with much greater 
 difficulty. Tetra-, penta-, and hexamethylene rings no longer behave 
 like unsaturated compounds, and are very stable in the presence of 
 halogens, hydrohalogen acids, and potassium permanganate. In 
 harmony with these views, the determination of the heats of combustion 
 of the simplest cyclo-paraffins showed a considerable decrease from 
 tri- to hexamethylene (B. 25, 496). According to Baeyer's tension 
 theory, the pentamethylene ring should form even more easily than the 
 hexamethylene ring a conclusion which led to successful attempts to 
 prepare pentamethylene derivatives (B. 28, 655). 
 
 METHODS OF RING FORMATION IN CYCLO-PARAFFIN BODIES. 
 
 Special importance is attached to the methods by which open 
 carbon chains are converted into closed carbon chains. In accordance 
 with the definition of nuclear syntheses as reactions in which previously 
 unlinked carbon atoms are linked together (Vol. I.), every transforma- 
 tion of an open carbon chain into a closed one must be regarded as a 
 nuclear synthesis. And indeed it is by well-known nuclear synthesis 
 methods applied to suitable aliphatic substances that the closing of 
 rings with formation of cyclo-paraffin bodies has been carried out. The 
 facts in question, already mentioned in divers places in Vol. I., con- 
 stitute the transition reactions joining the class of paraffins with that 
 
4 ORGANIC CHEMISTRY 
 
 of cyclo-paraffins. The most important items may be briefly 
 enumerated. 
 
 1. Cyelo-paraffins themselves are produced by the action of sodium 
 or zinc upon dibromo-substituted paraffins, the hydrobromic acid 
 esters of the glycols : 
 
 /CH 2 Br CH 2 CHBr.CH 3 CH /CH 2 CHBrCH 3 CH 2 CH 2 CH 2 Br 
 2 \CH 2 B | CH 2 CH 2 Br ' 2 \CH 2 CH 2 Br | CH 2 CH 2 CH 2 Br 
 
 I rH '/CH 2 I CH 2 CHCH 3 ! CH /CH 2 CHCH 3 I CH 2 CH 2 CH 2 
 2 \CH, CH 2 CH 2 2 \CH 2 CH 2 CH 2 CH 2 CH 2 
 
 a-Monobromine derivatives of the glutaric acid series yield tri- 
 methylene-carboxylic acids even when treated with alcoholic potash. 
 
 2. Intramolecular pinacone formation. Besides secondary alcohols, 
 the reduction of the ketones yields ditertiary glycols, the pinacones. 
 On reducing diacetyl-pentane we obtain besides an aliphatic disecondary 
 glycol a ditertiary glycol, a cyclic pinacone : 
 
 CH /CH 2 CH 2 CH(OH)CH 3 
 
 rH /CH 2 CH 2 CO.CH 3 _ 2 \CH 2 CH 2 CH(OH)CH 3 
 
 2 \CH a CH 2 CO.CH 3 __ ^ CH /CH 2 CH 2 C(OH)CH 3 
 
 2 \CH 2 CH 2 C(OH)CH 3 
 
 3. Cyclic syntheses with the aid of metallorganic compounds. By 
 
 treating the di-magnesium compound of the i, 5-dibromo-pentane with 
 acetic ester we obtain methyl-cyclo-hexanol. Carbonic acid reacts 
 with the formation of cyclo-hexanone : 
 
 CH 2 \ rn co 2 /CH 2 .CH 2 .MgBr CH.COOCH, /CH 2 CH 2 \ r /OH 
 
 ' Ha \CH 2 .CH 2 .MgBr~ ' H2 \CH 2 _CH 2 / '\CH 3 
 
 The synthesis of a tertiary alcohol from a magnesium alkyl iodide 
 and a ketone proceeds intramolecularly in the action of magnesium 
 upon 8-aceto-butyl iodide : 
 
 CH 2 .CH 2 I Mg CH 2 .CH 2 \ c /OMgI 
 
 CH 2 .CH 2 .COCH 3 "* CH 2 .CH 2 / '\CH 3 
 
 4. Intramolecular aceto-acetic ester condensation. When sodium 
 acts upon adipinic acid ester there is intramolecular condensation cor- 
 responding to the formation of acetic ester, and a cyclic /3-ketone- 
 carboxylic ester is formed : 
 
 CH 2 CH 2 COOC 2 H 5 _ CH 2 CH -- COOC 2 H 5 
 CH a CH 2 COOC 2 H 6 c a H 6 OH~" CH 2 CH 2 / CO 
 
 The same behaviour is shown by the esters of the pimelinic acids, 
 which yield j8-ketone acid esters with six-membered ring chains. 
 
 46. Oxalo-acetic ester condensation. The action of oxalic ester 
 and glutaric acid ester upon sodium ethylate produces diketo-penta- 
 methylene-carboxylic ester : 
 
 CH /CH 2 C0 2 C 2 H 5 COOC 2 H 5 _ > CH /CH(CO a C 2 H 5 ) CO 
 2 \CH 2 CO 2 C 2 H 5 COOC 2 H 6 2 \CH(CO 2 C 2 H 5 ) CO 
 
 Similar reactions are shown by /2-substituted glutaric acid ester, 
 acetone-dicarboxylic acid ester, methyl-ethyl-ketone, dibenzyl-ketone, 
 etc., with oxalic ester and sodium ethylate. 
 
METHODS OF RING FORMATION 5 
 
 40. Intramolecular formation of j9-diketones. y-acetyl-butyric 
 acid ester is condensed by sodium ethylate to diketo-hexamethylene ; 
 
 CH 2 CO CH 3 __ > CH 2 CO CH 2 
 
 CH 2 CH 2 COOC 2 H 5 CH 2 CH 2 -CO 
 
 With the same treatment the - and -ketonic acid esters yield extra- 
 cyclic /2-diketones of the pentamethylene and hexamethylene series. 
 
 5. Cyclic syntheses with malonic acid esters, acetic acid esters, etc. 
 Through the action of alkylene bromides upon sodium malonic acid 
 esters we obtain cyclo-paraffin acid esters (W. H. Perkin, jun.). 
 
 The reaction takes place in three phases : 
 
 CH^ + NaHClCOAHJ. _ CH 2 CH(C 0! C,H 6 ) 2 + NaBr 
 
 CH 2 Br CH 2 Br 
 
 CH 2 .CH(CO 2 C 2 H 5 ) 2 +NaHC(CO 2 C 2 H 6 ) 2 = CH 2 .CNa(CO 2 C 2 H 5 ) 2 
 CH 2 Br NaBr CH * Br +CH 8 (CO 2 C 2 H 5 ) 2 
 
 CH, CH,Br 2NaHC(CO,C.H.), 
 CH!-CH,Br - * 
 
 By introducing the bromination products of olefin-mono- and olefin- 
 dicarboxylic acid esters in the place of alkylene bromides, this reaction 
 has been used for preparing numerous trimethylene derivatives. 
 Cyano-acetic ester behaves like malonic ester (C. 1899, II. 36, 824). 
 
 If sodium aceto-acetic ester acts upon 1, 4-dibromo-n-pentane, 
 i, 2-methyl-acetyl-pentamethylene-carboxylic acid ester is produced: 
 
 CHNa.CO 2 C 2 H 5 _CH 2 .CH \ /CO 2 C 2 H S CH 2 CO 2 C 2 H 5 
 CH 2 .CH 2 .Br " r2 CO.CH 3 = CH 2 .CH 2 / \COCH 3 + COCH 3 +2NaBr 
 
 From i, 5-dibromo-pentane we correspondingly obtain a-acetyl-hexa- 
 methylene-carboxylic ester (B. 21, 742 ; 40, 3943). 
 
 6. From the di-sodium compounds of alkylene-dimalonic esters 
 iodine or bromine extracts the sodium with the formation of a ring, 
 just as iodine converts the sodium aceto-acetic ester into diaceto- 
 succinic ester, and mono-sodium malonic ester into dimalonic ester. 
 From the cyclo-paraffin-tetracarboxyUc acids thus produced we may 
 obtain cyclo-paramn-dicarboxylic acids by splitting off 2CO 2 (W. H. 
 Perkin, jun.). 
 
 Tri, tetra-, penta-, hepta-, octo-, and nonocarbocyclic compounds : 
 
 CH /CNa(C0 2 C 2 H 5 ) 2 _ H /C(CO a C 2 H 5 ) 2 _ CR /CHCO 2 H 
 
 2 \CNa(C0 2 C 2 H 6 ) 2 2 \C(C0 2 C 2 H 5 ) a 2 \CHCO 2 H 
 
 CH 2 CNa(C0 2 C 2 H 5 ) 2 _ CH 2 C(CO 2 C 2 H 5 ) 2 _ CH 2 CHCO 2 H 
 
 CH 2 CNa(C0 2 C 2 H 5 ) 2 ' CH 2 C(CO 2 C 2 H 5 ) 2 ' CH 2 CHCO 2 H 
 
 CH /CH 1 .CNa(C0 1 C 1 H B ) a __ >CH /CH 2 C(CO 2 C 2 H 5 ) 2 /CH 2 CHCO 2 H 
 
 ! \CH 2 .CNa(C0 2 C 2 H 5 ) 2 ! \CH 2 C(CO 2 C 2 H 6 ) 2 ! \CH a CHCO 2 H 
 
 7. Cyclic ketone formation. As the calcium salts of the paraffin- 
 monocarboxylic acids during distillation yield open ketones, so the 
 
ORGANIC CHEMISTRY 
 
 CH 2 CH 2 C0 2 \ Ca 
 CH 2 CH 2 C0 2 / 
 iCH 2 CH 2 \ CQ 
 CH 2 CH 2 / 
 
 CH /CH 2 CH 2 CH 2 C0 2 
 2 \CH 2 CH 2 CH 2 CO 2 
 
 I CH 2 < /CH 2 CH 2 CH 2 \ CO 
 \CH 2 CH 2 CH 2 / 
 
 c 
 
 XV 
 
 >.co 
 
 >Ca 
 
 calcium salts of some higher normal paraffin-dicarboxylic acids yield 
 during dry distillation cyclic ketones (J. Wislicenus) : 
 
 /CH 2 CH 2 C0 2 \ c CH 2 CH 2 CH 2 C0 2 \ c 
 Z \CH 2 CH 2 C0 2 / ' I CH 2 CH 2 CH 2 CO a / 
 - 1 CH 2 CH 2 CH 2 \ ro 
 
 *CH 2 CH 2 CH 2 / 
 CH 2 CH 2 CH 2 CH 2 CO 2 N 
 j CH 2 CH 2 CH 2 CH 2 - 
 j CH 2 CH 2 CH 2 CH 2 N 
 V CH 2 CH 2 CH 2 CH 2 / 
 
 7. During distillation at ordinary pressures the anhydrides of 
 adipinic and pimelinic acids and their alkyl substitution products split 
 into CO 2 and cyclic ketones (H. G. Blanc ; see Vol. I.). 
 
 8. Aliphatic diazo-compounds, like diazo-methane (Vol. I.) and 
 diazo-acetic ester, add themselves to olefin-mono- and -dicarboxylic 
 esters with the formation of cyclic azo-compounds or pyrazolin com- 
 pounds, which, by splitting off nitrogen, pass easily into trimethylene- 
 carboxylic acids (E. Buchner) : 
 
 N=N CHCO 2 R N=N CHCO 2 R_ N 
 
 ' + cL 2 
 
 C0 2 RCH 
 
 CO 2 RCH 
 
 H 2 
 
 N=N CHC0 2 R _ NZ 
 
 Cp. 
 
 N=N CHCO 2 R 
 
 \/ +11 = 
 CH 2 CHC0 2 R CH 2 CHC0 2 R 
 
 also the condensation of benzol with 
 
 CH 2 <| 
 
 CHCO 2 R 
 
 \CH 2 
 CHCO 2 R 
 
 diazo-acetic ester to 
 
 isophenyl-acetic or norcaradiene-carboxylic ester. 
 
 I.TRI-, TETRA-, PENTA-, HEPTA-, OCTO- AND NONO- 
 CARBOCYCLIC COMPOUNDS 
 
 A number of natural products are closely related to these groups 
 of carbocyclic compounds : carone, eucarvone, pinene, camphor, 
 tropin, ecgonin, pseudo-pelletierin, etc. This group of bodies, there- 
 fore, has lately grown in scientific and practical interest. 
 
 We may here first give a summary of the physical properties of 
 the simplest cyclo -paraffins (B. 40, 3981) : 
 
 
 
 
 
 Refractive 
 
 Name. 
 
 Melting-point. 
 
 Boiling-point. 
 
 Sp. G. at 4. 
 
 Index 
 
 
 
 
 
 for D Line. 
 
 Cyclopropane 
 
 Gaseous 
 
 Approx. -35 
 
 
 .. 
 
 Cyclobutane 
 
 Liquid 
 
 
 0-7038 
 
 37520 
 
 Cyclopentane 
 Cyclohexane 
 
 + 6-4 
 
 II 49 2 
 81 
 
 0-7635 
 0-7934 
 
 40855 
 4266 
 
 Cycloheptane 
 
 -12 
 
 118 
 
 0-8275 
 
 44521 
 
 Cyclooctane 
 
 + n "5 
 
 i 4 5-3-i48 
 
 0-850 
 
 44777 
 
 Cyclononane 
 
 
 
 o- 7 8 5 (?) 
 
 4328 
 
 The molecular refractions determined from the densities and 
 refractive indices indicated agree with those calculated from theory 
 
TRIMETHYLENE GROUP 7 
 
 (see Vol. I., Introduction). It follows that in the cycle -paraffins the 
 formation of rings has no influence upon the molecular refraction. 
 
 A. Trimethylene Group. 
 
 OH \ 
 
 Trimethylene (cyclopropane) ; 2 ;CH 8 is an easily condensible gas. 
 
 CH 2 / 
 
 It is obtained from trimethylene bromide with the aid of sodium 
 (Freund, 1882), or of alcohol and zinc dust (B. 20, R. 706 ; /. pr. Ch. 
 2, 7, 512). It may combine with bromine, especially in the presence 
 of HBr acid, whereby chiefly trimethylene bromide CH,Br.CH,CH.Br 
 is produced, or with hydriodic acid, forming n-propyl iodide, but 
 it does so with greater difficulty than propylene. At a red heat it 
 transforms itself into propylene (B. 29, 1297 ; C. 1899, I. 925, II. 287). 
 In the presence of finely divided nickel, hydrogen reduces it to propane 
 already at 80 (B. 40, 4459). MnKO solution does not oxidise tri- 
 methylene in the cold (B. 21, 1282). 
 
 Concerning the difference in the heats of formation of trimethylene 
 and propylene, see C. 1899, II. 801. 
 
 Methyl-trimethylene, b.p. 4 (B. 28, 22 ; C. 1902, I. 1277) ; 
 1, 1-Dimethyl-trimethylene b.p. 21 (C. 1899, I. 254; 1900, II. 1069) ; 
 1, 1, 2- and 1, 2, 3-Trimethyl-trimeth^lene (B. 34, 2856) ; Vinyl- 
 
 CH 2V 
 trimethylene I ;>CHCH=CH, b.p. 40, D 073, are produced in a 
 
 CH 2 
 
 peculiar reaction by the action of alcohol and zinc dust on the tetra- 
 bromate of penta-erythrite (see Vol. I.) ; by MnKO it is oxidised to 
 
 CH 2V CHOH 
 
 glycol I yen/ | , which, by further oxidation with dilute 
 
 CHy CH 2 OH 
 
 HNO 3 , yields a-oxy-glutaric acid ; with Br it forms a dibromide, 
 which, on treating with lead oxide, yields keto-pentamethylene (B. 29, 
 R. 780 ; C. 1897, H- 6 9 6 ; a 150 c - l8 9 8 > IL 475, footnote) ; with N 2 O 3 
 it gives a pseudo-nitrosite, m.p. 145, from which on reduction, besides 
 diamine C 5 H 8 (NH 2 ) 2 , b.p. i8o-i85, cyclo-butanone is formed (B. 41, 
 915). Concerning another interpretation of vinyl-trimethylene, see 
 B. 40, 3884. 
 
 Dimethyl-methylene-trimethylene I >C =C \ (?), b.p. 70-7i, 
 
 CH 2 CH<j 
 
 is produced from dimethyl- trimethylene-carbinol on boiling with acetic 
 anhydride (C. 1905, II. 403 ; 1909, I. 1859). 
 
 Monochloro-trimethylene, b.p. 43 (B. 24, R. 637). 
 
 Dichloro-trimethylene, b.p. 74 (B. 25, 1954). 
 
 Amino-trimethylene (C 3 H 5 )NH 2 , b.p. 49, from trimethylene- 
 carboxylic amide with KOBr (C. 1901, II. 579). Miscible with water 
 in all proportions. Smells like propylamine. With nitrous acid it 
 yields ally! alcohol, with splitting of the ring (C. 1905, I. 1704). 
 
 Trimethylene-methylamine (C 3 H 5 )CH 2 NH 2 , b.p. 86, from tri- 
 methylene-carboxylic nitrile by reduction. Gives with nitrous acid 
 trimethylene-carbinol and cyclo-butanol, with expansion of the ring 
 (B. 40, 4393) 
 
 Trimethyl-carbinol (C 3 H 5 )CH 2 OH, by the reduction of trimethylene- 
 carboxylic ester with Na and alcohol (B. 40, 4397). With concentrated 
 HBr it passes into 1,3-dibromo-butane (C. 1908^ I. 818), 
 
8 ORGANIC CHEMISTRY 
 
 Trimethylene-ethyl-earblnol, b.p. 14. 
 
 Trimethylene-isopropyl-carbinol, b.p. 151. 
 
 These two are obtained by reduction of the corresponding ketones. 
 
 Trimethylene - dimethyl - carbinol (C 3 H 5 )C(CH 3 ) 2 OH, by treating 
 Mg(CH 3 )I with acetyl-trimethylene or trimethylene-carboxylic ester ; 
 chloride, b.p. 132 ; bromide, b.p. 152. By oxalic acid it is isomerised, 
 with splitting of the ring, to dimethyl - tetramethylene oxide 
 
 Cnll^cH^ (B> 34 ' 3887) ' 
 
 2 Trimethylene-diethyl-carbinol (C 3 H 5 )C(C 2 H 5 ) 2 OH, b.p. 158. 
 
 Trimethylene-methyl-ethyl-carbinol (C 3 H 5 )C(CH 3 )(C 2 H 5 )OH, b.p. 
 141 (C. 1909, I. 1859). 
 
 CH 2 
 
 Trimethylene-aldehyde I V:H.CHO, b.p. 98, by oxidation of 
 
 CH 2 
 trimethylene-carbinol with chromic acid. 
 
 Acetyl-trimethylene ^>CH.cocH 3 , b.p. 113 : 
 
 1. From aceto-propyl-bromide with ejection of HBr by KOH 
 (C. 1898, II. 474). 
 
 2. From acetyl-trimethylene-carboxylic acid by heating. 
 
 3. By the action of Hg(OH 3 )I upon trimethylene cyanide. The 
 three-ring is split up by mineral acids. For homologous ketones see 
 C. 1909, I. 1859. 
 
 Trimethylene-carboxylic acids (A. 284, 197) are obtained by the 
 general methods of ring formation 5, 6, and by method 8, which only 
 leads to trimethylene-derivatives (p. 6). From those trimethylene- 
 polycarboxylic acids which contain two carboxyls bound with one 
 carbon atom, we obtain the carboxylic acids poorer in carboxyl by 
 splitting off CO 2 . Certain peculiar phenomena of isomerism (cis- and 
 trans-forms) are attributed to the position of the carboxyls on the 
 same side, or on different sides, of the trimethylene plane, as in the 
 case of the isomerisms of the tri-thio-aldehydes (Vol. I.). 
 
 Trimethylene-carboxylic acid C 3 H 5 CO 2 H, m.p. 18, b.p. 183, is 
 isomeric with crotonic acid. The trimethylene ring is split by bromine 
 with formation of a, y-dibromo-butyric acid (C. 1909, II. 1130). Its 
 nitrite, b.p. 118, has been obtained by distilling y-chloro-butyro-nitrile 
 over KOH ; ethyl ester, b.p. 134; chloride, b.p. 121; amide, m.p. 
 
 124 (C. 1901, II. 579 I 9 02 I- 9 I 3)- 
 
 CH COOH 
 Trans - phenyl - trimethylene - carboxylic acid C 6 H 5 CH<^ j 
 
 CH 2 
 
 m.p. 105, has been obtained by method 8, by addition of diazo-acetic 
 ester to styrol (q.v.). It was successfully disintegrated to cis-trans- 
 trimethylene-i, 2-dicarboxylic acid. 
 
 2, 2 - Dimethyl - trimethylene - carboxylic acid (CH 3 ) 2 c/^ COOH 
 
 \CH 2 
 
 b.p. 100, smells strongly of butyric acid. The ester, b.p. 90, is formed 
 by separation of HBr from the 3, 3-dimethyl-y-bromo-butyric acid 
 ester (C. 1907, II. 897). 
 
 Trimethylene-1, 1-dicarboxylic acid (vinaconic acid] 
 
 m.p. 140 (see method 5, p. 5). With HBr this passes into brom- 
 ethyl-malonic acid CH(CO 2 H) 2 BrCH 2 CH 2 . It also takes up bromine 
 
TRIMETHYLENE GROUP 9 
 
 (B. 18, 3314), but is not affected by HNO 3 , MnKO 4 , or nascent hydrogen 
 (B. 23, 704 ; 28, 8). With Na-malonic ester the ester of vinaconic 
 acid condenses to butane-tetracarboxylic ester, and thus behaves quite 
 like a, p-olefin-carboxylic ester (see Vol. I. and B. 28, R. 464). Con- 
 cerning the constitution of vinaconic acid and the homologous methyl- 
 vinaconic acid, see A. 294, 89. 
 
 1, 1-Cyano-trimethylene-earboxylic acid, m.p. 149, from sodium- 
 cyan-acetic ester and ethylene bromide (C. 1899, H- 824). 
 
 Acetyl-trimethylene-carboxylie ester 2c < s ^ b -P- I 95> 
 
 CH 2 / \COOC 2 H 5 
 from sodium-aceto-acetic ester and ethylene bromide (B. 17, 1440). 
 
 Trimethylene-1, 2-dicarboxylic acid is known in two isomeric forms, 
 distinguished as cis- and cis-trans- or trans- forms (A. 245, 128) : 
 
 C0 2 H C0 2 H C0 2 H H 
 
 ft\CH 2 /CO 2 H 
 T-cis- form. T-cis-trans- form. 
 
 Cis-trimethylene-1, 2-dicarboxylic acid, m.p. 139; anhydride, 
 m.p. 59, is obtained from tr-i, 2-tri- and -I, 2-tetracarboxylic acid by 
 heating. Cis-trans-trimethylene-i, 2-dicarboxylic acid, m.p. 175, 
 from monobromo-glutaric acid ester with alcoholic caustic potash 
 (C. 1900, I. 284). It has been separated into two optically active com- 
 ponents by means of its quinine salt, like the cis-trans-trimethylene- 
 
 1, 2, 3-tricarboxylic acid described below (B. 38, 3112). Its methyl ester, 
 b.p. about 210, is obtained from acryl-diazo-acetic ester by method 8, 
 besides glutaconic acid ester ; and from fumaric acid ester with diazo- 
 methane (B. 27, 1888 ; 28, R. 290). 
 
 Cis-phenyl-trans-2, 3- trimethylene - dicarboxylic acid 
 c eH 5 CH/COOH ? m.p. 175; anhydride, m.p. 134; from a-bromo- 
 
 benzylidene-bis-malonic ester with alcoholic ammonia, or by adding 
 diazo-acetic ester to cinnamic-acid ester (B. 36, 3774 ; /. pr. Ch., 
 
 2, 75, 490). 
 
 Trimethylene-1, 2-tricarboxylic acid CH *\^COH' m ' p ' l87 ' by 
 disintegration. Its ethyl ester, b.p. 276, from a, p-dibromo-propionic- 
 acid ester (B. 17, 1187), and from a-brom-acrylic ester with Na-malonic- 
 acid ester by method 5 (B. 20, R. 140, 258). 
 
 Sym. trimethylene-1, 2, 3-tricarboxylic acid C 2 HCH2 ' cis " 
 
 form, m.p. I5o-i53 ; cis- trans-form, m.p. 220 ; anhydride, m.p. 187, 
 b.p. 265. The cis-acid is obtained from the I, 2, 3-tetracarboxylic 
 acid (B. 17, 1652), the cis-trans-acid from fumaric-acid-diazo-acetic 
 ester (B. 23, 2583). The latter acid is also obtained from the oxidation 
 of isophenyl-acetic or norcaradiene-carboxylic acid (B. 27, 868). 
 
 Trimethylene-1, 2-tetracarboxylic acid CH /^ c 2 2! 2 passes at 200 
 
 \C(CO 2 H) 2 
 
 into the anhydride of the cis-i, 2-dicarboxylic acid. Its ethyl ester, 
 m.p. 43, b.p~ 12 187, is obtained from method 6 (B. 23, R. 241). 
 
 Trimethylene-1, 2, 3-tetracarboxylic acid ( CO 2 H ) 2 C<^^: 2 ^ passes 
 at 95-ioo into cis-i, 2, 3-tricarboxylic acid. Its ethyl ester, 
 
io ORGANIC CHEMISTRY 
 
 b.p. 246, from dibromo-succinic ester by method 5. The cis-i, 2,- 
 trans-i, 3 acid decomposes at i^6-ig8 (B. 28, R. 290). 
 
 1, l-i)imethyl-trimethylene-2, 3-diearboxylic acid, caronic acid 
 
 (CH 3 ) 2 C/^ ^ 2 S> trans-form, m.p. 213, passes on heating with acetic 
 \CHCO 2 H 
 
 anhydride into the cis-form, m.p. 176. The anhydride of the cis-form 
 melts at 55. The caronic acids are obtained by oxidation with 
 MnO 4 K from carone (see Terpene ketones), which therefore contains a 
 trimethylene ring. Synthetically, the caronic acids have been obtained 
 from a-bromo- (3 (3-dimethyl-glutaric-acid ester with alcoholic potash 
 (C. 1899, I. 522). By heating with HBr the caronic acids are easily 
 transformed into terebinic acid (q.v.). On heating cuii-dibromo- (3 (3- 
 dimethyl-glutaric ester with alcoholic potash we obtain etho-oxy- 
 
 caronic acid (CH 3 ) 2 C<(^ ( ? ) ^ )CO2H , m.p. 138 (C. 1901, II. no). 
 
 1, 2-Dimethyl-trimethylene-2, 3-dicarboxylic acid, m.p. 154, is 
 identified with the acid the ester of which is obtained with PC1 5 from 
 oxy-trimethyl-succinic ester (C. 1908, I. 627). 
 
 The 1, l-dialkyl-2, 3-dicyano-trimethylene-2, 3-dicarboxylic acids 
 
 have been obtained in considerable numbers in the form of imides of 
 
 the general formula R /C\^N) CO/ NH ' from the corres P ondin g 
 dialkyl-dicyano-bromo-glutarimides (C. 1899, II. 439 ; 1901, I. 57). 
 
 Trimethylene-tricyano-tricarboxylic-acid ester Rpc?cicNi/ c \cooR' 
 m.p. 119, is formed by the action of bromine or iodine upon sodium- 
 cyano-acetic ester in ether ; on saponification it yields trimethylene- 
 tetra- and then -i, 2, 3-tricarboxylic acid (B. 33, 2979). 
 
 Methyl-eyelo-propene-dicarboxylic acid CH 3 CH <^|cQ 2 HJ> m -P- 200 > 
 see B. 26, 750. 
 
 B. Tetramethylene Group. 
 
 For obtaining tetramethylene compounds the ring formation 
 methods i, 5, and 6 are used. 
 
 PTT _ PT-T 
 
 Tetramethylene-cyclo-butane cj-f CH' b ' p ' Il0 - I2 > D 4 73 8 > 
 is obtained by reducing cyclo-butene with Ni and H at 100 ; at higher 
 temperatures butane is also produced, with splitting of the ring. It 
 possesses a very feeble odour, and burns with a luminous flame. In 
 the cold it is stable in the presence of bromine and concentrated HI. 
 
 Methyl-tetramethylene - 01 * 3 ' b -P- 39-42, method i, p. 4. 
 
 Cyclo-butene ^ 2 CH' easilv condensible gas of b.p. i'5-2, 
 D 4 0-733, generated together with A 1>3 -butadiene during dry distilla- 
 tion of cyclo-butyl-trimethyl-ammonium hydroxide. Adds bromine, 
 forming i, 2-dibromo-cyclo-butane, b.p. 24 69, m.p. 2, which, with 
 KOH, splits off HBr and passes into bromo-cydo-butene. This is an 
 oil of penetrating odour, b.p. 92, which oxidises to succinic acid. With 
 bromo-cyclo-butene as a starting-point, a number of bromo-substitution 
 products of cyclo-butane have been prepared. Thus it combines with 
 HBr to 1, 1-dibromo-cyelo-butane (I.), b.p. 158, and with Br to 1, 1, 2- 
 tribromo-cyclo-butane (!!.)> b.p. 19 109. This gives with alcoholic 
 
TETRAMETHYLENE GROUP u 
 
 KOH, 1, 2-dibromo-eyclo-butene (III.), b.p. 155, distinguished by a 
 great faculty for polymerisation. With KMnO 4 it oxidises to succinic 
 acid, and combines with Br to form 1, 2-tetra-bromo-eyclo-butane (IV.), 
 m.p. 126, which, on further bromination, yields pentabromo-cyelo- 
 butane C 4 H 3 Br 5 , b.p. 19 i75-i85, and hexabromo-cyclo-butane 
 C 6 H 2 Br 6 , m.p. 186-5, which is remarkable for its ease of crystallisation 
 (B. 40, 3979)- 
 
 (I.) (II.) (HI.) (IV.) 
 
 CH 2 CBr_ CH 2 CBr 2 CH 2 CBr 2 CH a CBr_ CH 2 CBr 2 
 
 CH 2 CH "^CHa CH 2 CH 2 CHBr ~^CH 2 CBr ~* CH 2 CBr 2 
 
 The name dimethyl-methylene-tetramethylene ( _ c ^ J , b.p. 
 
 ioo-iO2, is given to the hydrocarbon generated from the bromide of 
 dimethyl-tetramethylene-carbinol by splitting off HBr. On reduction 
 with HI it passes into i, 3-dimethyl-pentamethylene. 
 
 Oxy-tetramethylene, cyclo - butanol C 4 H 7 OH, b.p. 123, from 
 amido-tetramethylene by the action of HNO 2 , and by electrolysis of 
 potassium tetramethylene-carboxylate (B. 40, 2594, 4962). 
 
 Amido-tetramethylene C 4 H 7 .NH 2 , b.p. 81, arises from the amide of 
 tetramethylene-carboxylic acid with bromine and an alkali (B. 40, 4745). 
 
 Tetramethylene-methylamine ^ 2 rS' CH2NH2 > b.p. 110, by 
 
 L/rl 2 .UJrl 2 
 
 reduction of tetramethylene-cyanide, gives, with HNO 2 , a mixture of 
 tetramethylene-earbinol C 4 H 7 .CH 2 OH, and cyclo-pentanol C 5 H 9 .OH. 
 
 Tetramethylene-carbinol C 4 H 7 .CH 2 OH, b.p. 142, by reduction of 
 tetramethylene-carboxylic ester with Na and alcohol ; bromide, b.p. 
 i37-i39(B. 40,4959). 
 
 Tetramethylene-methyl-carbinol C 4 H 7 .CH(OH)CH 3 , b.p. 144, by 
 reduction of tetramethylene-methyl-ketone. 
 
 Tetramethylene-dimethyl- and diethyl-earbinol, b.p. 147 and 188 
 respectively, by the action of Mg(CH 3 )I and Mg(C 2 H 5 )I on tetramethy- 
 lene-carboxylic ester (C. 1905, II. 761 ; 1908, II. 1342). 
 
 Tetramethylene-diethyl-glyeol [C 4 H 7 C(OH)C 2 H 5 ] 2 , m.p. 95, by 
 reduction of tetramethylene-ethyl-ketone. 
 
 Keto-tetramethylene-cyclo-butanone ;^ 2 ~^ b.p. 09, D 
 
 L/Jtl 2 ^rl 2 
 
 0-9548, generated (i) by action of bromine and alkali on a-bromo- 
 tetramethylene-carboxylic amyl ; (2) during boiling of i, i-dibromo- 
 butane with lead oxide and water. Nitric acid oxidises it to succinic 
 acid (C. 1908, I. 123). 
 
 Tetramethylene-methyl- and ethyl-ketone, b.p. 135 and 145, from 
 the carboxyl chloride with zinc alkylene (B. 25, R. 371), or from the 
 amide with Mg(CH 3 )I (B. 41, 2431). 
 
 Di-tetramethylene-ketone (C 4 H 7 ) 2 CO, b.p. 205, from the calcium 
 salt of carboxylic acid. 
 
 Dimethyl- and diethyl-tetramethylene-ketone CzU ^l 
 
 L-rl 2 UrlU 2 rl 5 
 
 m.p. 45-i20 and i6o-i65. This constitution is ascribed to 
 substances obtained during distillation of Ba salts of 
 and diethyl-glutaric acid (C. 1897, II. 342). 
 
 1, 3-Dimethyl-2, 4-diketo-tetramethylene C 
 
12 ORGANIC CHEMISTRY 
 
 by saponification and rejection of CO 2 from the corresponding car- 
 boxylic-acid ester, on boiling with bartya water. 
 
 1, 1, 3, 3-Tetramethyl-2, 4-diketo-tetramethylene 
 
 m.p. 116, obtained by rejection of HC1 from iso-butyryl chloride. Also 
 by action of molecular silver on bromo-iso-butyryl bromide. In both 
 cases we must assume the formation of dimethyl-ketene (see Vol. I.), 
 which easily polymerises to tetramethyl-2, 4-diketo-tetramethylene. 
 Its odour recalls both menthol and camphor, and it has the great 
 volatility of these compounds. 
 
 Dioxime, m.p. 281 (B. 39, 970). 
 
 Tetramethylene-carboxylie acid C 4 H 7 CO 2 H, b.p. 194, smells like 
 the fatty acids, and is generated from I, i-dicarboxylic acid ; on 
 reduction by HI it yields n-valerianic acid, with splitting of the ring 
 (C. 1908, II. 1342). Ethyl ester, b.p. 160 ; chloride, b.p. 142 ; 
 anhydride, b.p. 160 ; amide, m.p. 130 ; nitrite, b.p. 150 (B. 21, 2692 ; 
 C. 1899, II. 824). 
 
 Tetramethylene-1, 1-dicarboxylie acid melts at 155, passing into 
 monocarboxylic acid. Its ethyl ester, b.p. 224, by method 5, p. 5 ; 
 nitrile ester, b.p. 214, from trimethylene bromide, and sodium cyan- 
 acetic ester (C. 1899, II. 824 ; 1905, II. 761). 
 
 Cis-tetramethylene-1, 2-dicarboxylie acid, m.p. 137, from tetra- 
 carboxylic acid. Anhydride, m.p. 77, b.p. 271 (B. 26, 2243). Heating 
 with HC1 to 190 produces the trans-acid, m.p. 131 (B. 27, R. 734). By 
 bromination with Br and P, i, 2-dibromo-tetramethylene-dicarboxylic 
 acid is produced ; and its ester, on treating with alcohol and KI, passes 
 
 f^TT C^f^C} TT 
 
 into the ester of cyclo-butene-dicarboxylic acid H 2 ~ccQ 2 H' m '^' I 7^- 
 The latter easily yields an anhydride (/. Ch. Soc. 65, 950). 
 
 Tetramethylene-1, 3-dicarboxylie acid, cis-form, m.p. 136 ; anhy- 
 dride, m.p. 51; trans-form, m.p. 171, have been obtained from the 
 products of the action of formaldehyde upon malonic ester, and from 
 a-chloro-propionic-acid ester, with the aid of Na alcoholate (C. 1898, 
 II. 29). Also produced by boiling p-methoxy-methyl-malonic ester 
 with concentrated HC1 with the loss of two molecules of methyl 
 alcohol, by saponification, and CO 2 -rejection, from the tetra-carbo- 
 ester first formed (C. 1909, I. 152) : 
 
 CH 3 CH 2 CH (COOR) 2 CH 2 C (COOR) 2 
 
 + ---- > 
 
 (ROCO) 2 CH CH 2 OCH 3 (ROCO) 2 C -- CH 2 
 
 Tetramethylene-1, 2-tetracarboxylie acid, m.p. i45-i5o, by trans- 
 formation into cis-i, 2-dicarboxylic acid. Its ester is formed by 
 method 6, p. . 
 
 Diaeetyl-tetramethylene-dicarboxylic ester by method 6, p. 5 
 (B. 19, 2048). 
 
 Keto-tetramethylene-tricarbo-esters, such as : 
 
 CO-CHCOOR CO-CQ- R CO-C<C* R 
 
 I /CH I I r-u I /rw 
 
 ROCOCH - C <COOR ROCOCK - C <,COOR ROC CH C <COOR 
 
 are formed by condensation of Na-malonic esters, or methyl and ethyl 
 
TETRAMETHYLENE GROUP 13 
 
 malonic esters, with citraconic ester in alcoholic solution, in which 
 process probably the tetracarboxylic esters first formed with open 
 chains undergo " cyclic aceto-acetic ester condensation. By saponi- 
 fication with HCf two carbox-ethyl groups are split off the above 
 substances, and the following i-keto-tetramethylene-3-car boxy lie acids 
 are formed (B. 33, 3751) : 
 
 CO - CH 2 CO -- CHCH 3 CO - CHC,H 6 
 
 CH '-<COOH 
 
 1, 3 - Dimethyl -2, 4 - diketo - tetramethylene - earboxylic ester 
 
 CH 3 
 
 CO _ C _ COOC 2 H 5 , m.p. I33-I35, has been obtained by the action 
 CH 3 CH CO 
 
 of concentrated sulphuric acid upon sym. dimethyl-acetone-dicar- 
 boxylic ester. By alkalies the ring is easily split again (B. 40, 1604). 
 
 Diethyl - diketo - tetramethylene - dicarboxylic ester, 
 
 C 2 H 5 
 
 c COOC 2 H 5 b ca II3 _n6 i s identified with the 
 C 2 H 5 OCOC CO 
 
 C 2 H 5 
 
 dimeric ethyi-ketene-carboxylic ester. During distillation at ordinary 
 pressures it is depolymerised. Anilin also splits the molecule, forming 
 ethyl-malonic-ester anilide (B. 42, 4908). 
 
 Tetramethylene-l,3-diglyoxylic acid ' ^^H^CO.CO.H* m ' p ' 
 240, produced by condensation of tartaric acid and paraformaldehyde 
 with concentrated H 2 SO 4 . Decomposes into ethylene and oxalic acid 
 by heating with alkalies, and, on further heating with H 2 SO 4 , it passes 
 into a dilactone (B. 29, 2273). 
 
 By polymerisation of olefin and acetylene carboxylic acids, we 
 sometimes obtain substances with a four-membered carbon ring : 
 
 Diphenyl - tetramethylene - dicarboxylic acid, a-truxillic acid, 
 
 QH!CHICHCOOS' m ' P - 275 ' f rmS fr m Cmnamic add (?") b y 
 illumination (B. 35, 2908, 4128), and is found among the subsidiary 7 
 alkaloids of coca'in (q.v.). By distillation it again decomposes into 
 two molecules of cinnamic acid. 
 
 Diphenyl -tetrene- dicarboxylic acid ^ B S = ^1 , m.p. 259, 
 
 U c rl 5 U =vAAJUrl 
 
 formed by polymerisation of phenyl-propiolic acid, on heating, or 
 with POC1 3 ; easily forms an anhydride or imide (B. 35, 1407). 
 Pinic acid C '" and norpinic acid CO ^ H 
 
 are disintegration products ol pinene (see Terpenes), in which a tetra- 
 methylene ring, the so-called piceane ring, is assumed. 
 
 C. Pentacarbocyclic Compounds. 
 
 The number of known pentacarbocyclic compounds is much 
 greater than that of the tri- and tetracarbocyclic compounds. They 
 are derived partly from cyclo-pentane or pentamethylene, partly from 
 cyclo-pentene. Cyclo-pentadiene is found in the inital products of raw 
 benzene, as obtained from coal-tar. Pentamethylenes, and hexa- 
 
14 ORGANIC CHEMISTRY 
 
 methylenes, have also been obtained from the naphthenes of Caucasian 
 petroleum; and hexamethylenes are partially transformed into the 
 isomeric pentamethylene derivatives by heating alone, or with HI 
 under pressure (cp. A. 324, I, etc.). Cyclo-pentane and its progeny 
 have been obtained, not only by the methods of ring synthesis 
 specified on pp. 4, 5, and 6, but also from hexacarbocyclic ring ortho- 
 diketones by intramolecular atomic displacement (see Chloro-diketo- 
 pentamethylene) . This last reaction will be met with again in dealing 
 with the disintegration of aromatic substances. In the same manner 
 some remarkable pentamethylene derivatives have been obtained from 
 hexa-oxy-benzol : croconic acid and leuconic acid, which are dealt with 
 below under hexa-oxy-benzol. 
 
 Camphor, which is easily converted into aromatic substances, and 
 which contains a five-membered carbon ring, the so-called " campho- 
 ceanic ring," gives in different reactions pentamethylene derivatives, 
 e.g. camphorphorone, camphoric acid, campholenic acid, campholytic 
 acid, etc. Camphor and its cyclic transformation products are dealt 
 with in connection with the terpenes among the hydro-aromatic 
 compounds, after the benzol derivatives. 
 
 i. HYDROCARBONS. Pentamethylene, R-pentene, cyclopentane 
 
 _ 
 
 2 2 , b.p. 50, from pentamethylene iodide by reduction. 
 
 V^Jrio ^-'^"2 
 
 Methyl-pentamethylene, b.p. 70, contained in the so-called hexa- 
 naphthene from Caucasian petroleum (C. 1898, II. 412, 576) ; formed 
 synthetically from I, 5-dibromhexane, also from methyl-cyclopenta- 
 none, as well as tert.-methyl-cyclopentanol (C. 1899, I- I211 ' B. 35, 
 2686). 1,2-Methyl-ethyl-eyelopentane, b.p. 124. 1, 3-Dimethyl- 
 pentamethylene, b.p. 93, from the corresponding ketone, is optically 
 inactive ; but from the iodide of the i, 3-dimethyl-tert. -cyclopentanol 
 by reduction an optically active i, 3-dimethyl-cyclopentane, b.p. 
 91, [a] D 1-78, and also from i, 3 -ethyl -methyl -cyclopentanol 
 1, 3-Methyl-ethyl-cyelopentane, b.p. 121, [a] D 4-34, is obtained 
 (B. 35, 2678). 1, 2-Diphenyl-pentamethylene, m.p. 47, and 1, 2, 3, 4- 
 Tetraphenyl-pentamethylene from anhydro-aceton- and anhydrodi- 
 benzyl-ketone-benzile (C. 1901, II. 407, 1310). Triphenyl-methyl- and 
 Triphenyl-dimethyl-pentamethylene from the corresponding cyclic pina- 
 cones (C. 1903, I. 568). 
 
 Dipentamethenyl, dicyclopentyl C 5 H 9 -C 5 H 9 , b.p. 190, from penta- 
 methenyl bromide with Na (C. 1899, II. 367). 
 
 Cyclopentene CH \^ ICH*' b ' p< ^' from P entametn y lene iodide 
 or bromide with potash, or from cyclopentanol with P 2 O 5 (C. 1899, II. 
 367), yields with ozone an ozonide C 5 H 8 O 3 , which in water decom- 
 poses, forming glutardialdehyde (B. 41, 1701). Perchloro-cyelopentene 
 C 5 C1 8 , m.p. 41, b.p. 283, from hexachloro-cyclopentenone with PC1 5 
 
 (B. 23, 2214). Methyl-eyclopentene CH <cS 2 -CH^ H3 ' b -P- 7> M" 
 59-07, from 3-methyl-cyclopentanol by means of zinc chloride or 
 oxalic acid, also from the iodide with KOH. By oxidation it is split 
 into a-methyl-glutaric acid, which, together with the optical activity, 
 proves the formula assumed (B. 26, 775 ; 35, 2491). Isomeric with 
 
 the methyl-cyclopentene istheMethylene-cyelopentane 52 2 '^S 2 ^>C =CH 2 , 
 
PENTACARBOCYCLIC COMPOUNDS 15 
 
 b.p. 78-8i, a liquid of penetrating odour, produced from cyclopentene- 
 acetic acid by rejection of CO 2 ; nitro so-chloride, m.p. 81. Gives a 
 glycol, m.p. 40, by oxidation with MnO 4 K, and also cyclopentanone 
 (A. 347, 325). Similarly, 1 - Methyl - 3 - methylene - cyelopentane 
 CH 2 = ;** 2 )>CH.CH 3 has been obtained from methyl-cyclopentene- 
 
 Orij.L/jlg/ 
 
 acetic acid. By oxidation it is split into i, 3-methyl-cyclopentanone 
 (B. 34, 3950 ; C. 1902, I. 1222). Like methyl-cyclopentene, it is 
 optically active. In comparison with the corresponding saturated 
 hydrocarbons, the strong optical activity of the unsaturated hydro- 
 carbons with five-membered rings is very remarkable. 
 
 Ethylidene-eyelopentane **\C:CHCH 3 , b.p. 114, Isopropyl- 
 
 idene-eyclopentane *~ : 8cc <o 3 } b -P- 136, from cyclopentene- 
 
 CH 2 CHj / XCHj 
 
 isobutyric acid, with displacement of the double linking. By alcoholic 
 sulphuric acid it is isomerised to AMsopropyl-cyclopentene (A. 353, 
 307)- 
 
 Cyclopentadiene, pentol (cp. B. 22, 916) CH *<H=CH' b ' p ' 4I ' 
 an initial product in obtaining raw benzene from coal-tar, is a colour- 
 less liquid, violently attacked by both acids and alkalies. It reduces 
 ammoniacal silver solution. It soon polymerises, at ordinary tem- 
 peratures, to a bimolecular compound, Dicyclopentadiene (C 5 H 6 ) 2 , 
 b.p. 35 88, which at 170 boils with partial re-formation of cyclopenta- 
 diene. It is much more stable than the monomolecular compound, 
 and resembles the terpenes in its behaviour (B. 39, 1492 ; C. 1906, 
 II. 1403). On heating under pressure, both the simple and the dimeric 
 cyclopentadiene are transformed into a higher-molecular polymer, 
 which again can be split to simple cyclopentadiene (B. 35, 4151)." 
 
 The H atoms of the CH 2 group of cyclopentadiene have reaction 
 capacities similar to those contained in the group .CO.CH 2 .CO 
 (see Vol. I.). With K in benzene solution it yields the highly reactive 
 potassium-cyclopentadiene, which absorbs CO 2 with formation of a 
 potassium salt of the bi-cyclopentadiene-carboxylic acid (C 5 H 5 . 
 COOH) 2 , m.p. 210, and dimethyl ester, m.p. 85. With oxalic ester 
 cyclopentadiene in the presence of sodium ethylate it condenses to cyclo- 
 pentadiene-oxalic ester C 5 H 5 .COCOOC 2 H 5 ; with N 2 O 3 an isonitro-deri- 
 vative is formed. With aldehydes and ketones, under the influence of 
 Na alcoholate, coloured hydrocarbons are formed, which, referred to the 
 hypothetical simplest representation j f\C=CH 2 , are termed 
 
 OH. =d~i/ 
 
 fulvenes: Dimethyl-fulvene C 5 H 4 : C(CH 3 ) 2 , b.p. 46; Methyl-ethyl- 
 fulvene C 5 H 4 : C(CH 3 )C 2 H 5 , b.p. 185, orange-coloured oils ; Diphenyl- 
 fulvene C 5 H 4 : C(C 6 H 5 ) 2 , deep-red prisms, m.p. 82. Further fulvenes, 
 see A. 348, I. Like cyclopentadiene itself, the fulvenes absorb the 
 oxygen of the air, and form peroxides, e.g. [C 5 H 4 : C(CH 3 ) 2 ]O 4 (B. 33, 
 666 ; 34, 68, 2933). 
 
 Cyclopentadiene unites with the quinones in molecular proportions 
 to form stable compounds, like cyclopentadiene-quinone C 1]L H 10 O 2 , 
 greenish-yellow flakes of m.p. 78 (A. 348, 31). With I or 2 molecules of 
 the halogen hydrides and the halogens cyclopentadiene yields addition 
 products like : monochloro-cyclopentene C 5 H 7 C1, b.p. 40 50 ; trichloro- 
 
16 ORGANIC CHEMISTRY 
 
 cyclopentane C 5 H 7 C1 3 , b.p. 196; tetrachloro-cyclopentane C 5 H 6 C1 4 , 
 b.p. 15 94. Monochloro-cyclopentene gives with anilin anilino-cyclo- 
 pentene QH 7 .NC 5 H 10 , b.p. 23 94-96 (B. 33, 3348). By adding 2 Br 
 to the conjugate double links of cyclopentadiene (Thiele), two stereo- 
 
 isomeric i vf-dibromides are generated ZcHB^ 01 ^ 2 ' a so ^ one 
 and a liquid one, which, on oxidation, yield two stereo-isomeric aa r 
 dibromo-glutaric acids (A. 314, 296). Methyl-ethyl-cyclopentadiene, 
 see below. 
 
 1, 2, 4-Triphenyl- and 1, 2, 3, 4-Tetraphenyl-cyclopentadiene, m.p. 
 149 and 177, as well as triphenyl-methyl- and triphenyl-dimethyl- 
 cyclopentadiene, m.p. 163 and 128, are obtained from the corre- 
 sponding cyclic pinacones by splitting off 2H 2 O (C. 1898, II. 924 ; 
 1903, I. 568 ; B. 36, 933). 
 
 2. ALCOHOLS. Cyclopentanol C 5 H 9 OH, b.p. 139; chloride, b.p. 
 115 ; bromide, b.p. 137 ; iodide, b.p. 164 ; amine, b.p. 107 (A. 275, 
 322). 3-Methyl-cyclopentanol HOCH/^ 2 ~^ CH3 , b.p. 12 49; amine, 
 
 b.p. 12 42 (B. 25, 3519 ; 26, 775). Both alcohols are obtained by the 
 reduction of the corresponding ketones. 
 
 2-Methyl-cyclopentanol, b.p. 148, from methyl-cyclopentenone. 
 I- or tert.-methyl-cyclopentanol, m.p. 30, b.p. 136, from the corre- 
 sponding amine, b.p. 144, obtained by reduction from the nitrification 
 product of methyl-pentamethylene ; also from cyclopentanone with 
 CH 3 MgI, as well as by direct synthesis from S-aceto-butyl-iodide with 
 Mg (p. 4, and B. 35, 2684 ; C. 1899, I. 1212). 
 
 1, 3-Dimethyl-tert.-cyclopentanol, b.p. 94 89, from i-methyl-3- 
 cyclopentanone with CH 3 MgI (B. 34, 3950). 
 
 Pentamethylene-glycol C 5 H 8 (OH) 2 , m.p. 49, b.p. 12 127, from the 
 dibromide of the cyclopentene (C. 1899, II. 367). A further number 
 of glycols of the pentamethylene series have been obtained by intra- 
 molecular pinacone formation (p. 4) by reduction from the I, 5-di- 
 ketones (see C. 1901, II. 406 ; 1903, I. 588). 
 
 Pentamethylene-earbinol C 5 H ? CH 2 OH, b.p. 162, from cyclo- 
 pentyl-magnesium chloride and trioxy-methylene. Also by the action 
 of HNO 2 on pentamethylene-methylamine C 5 H 9 CH 2 NH 2 , b.p. 139- 
 145, besides the cyclohexanol (q.v.) produced by a peculiar ring 
 expansion (A. 353, 325 ; B. 41, 2629). 
 
 1-Isopropyl-cyclopentane-l, 6-diol CH'-CH 2 2 / C(OH) ~ C(OH) \CH3' 
 m.p. 62, b.p. u 108, produced by action of CH 3 MgI upon a-oxy-cyclo- 
 pentane-carboxylic ester. On heating with dilute SO 4 H 2 or oxalic 
 acid, the pinacone undergoes the pinacolin transformation with 
 extraordinary facility, 2, 2-dimethyl-cyclohexanone being formed 
 with displacement of a methylene group and expansion of the ring 
 (A. 376, 152). 
 
 C(OH) <CH 3 
 
 3. RING-KETONES.^ The cyclic ketones obtained from calcium salts 
 and the anhydrides of adipinic acid and the alkyl-adipinic acids by 
 methods 7 and 70, p. 6, formed the starting material for the prepara- 
 
PENTACARBOCYCLIC COMPOUNDS 17 
 
 tion of the corresponding alcohols, from which later the saturated, 
 and unsaturated, pentacarbocyclic hydrocarbons were obtained. 
 The oximes of these ketones yield on treatment with concentrated 
 SO 4 H 2 , S-lactames by Beckmann's transformation (see Vol. I.). 
 
 Adipin-ketone [cyclopentanone], keto-pentamethylene CO \ CH 2 /> H 2 , 
 
 b.p. 130, is found in the wood acids (B. 31, 1885), and is also generated 
 from 2-keto-pentamethylene-carboxylic ester by ketone splitting. 
 It smells like peppermint, and yields n-glutaric acid on oxidation. 
 Oxime, m.p. 120 (A. 275, 312). Heating with acetic anhydride to 180 
 gives, with partial enolisation, cyclopentenol acetate, b.p. I56-I58. 
 With benzaldehyde, adipin-ketone condenses easily to a mono- or 
 dibenzal compound C 6 H 5 CH : (C 5 H 6 O) and C 6 H 5 CH : (C 5 H 4 O) : CHC 6 H 5 
 (B. 29, 1601, 1836; 36, 1499; c - 1908, I. 637). With HNO 2 we 
 get di-iso-nitroso-cyclopentanone HON : (C 5 H 4 O) : NOH, m.p. 215 
 (C. 1909, II. 1549). By sodium ethylate two and three molecules of 
 the cyclopentanone are condensed, forming cyclopentane-pentanone 
 (C 5 H 6 O) : (C 5 H 8 ), b.p. 12 118, and cyclodipentane-pentanone (C 5 H 8 ) : 
 (C 5 H 4 O) : (C 6 H 8 ), m.p. 77, b.p. 12 190 (B. 29, 2962). 3-Methyl-cyclo- 
 
 pentanone COCU ^ b -P- T 42 , is optically active, [a] 135-9 
 
 (B. 35, 2489), and smells like camphorphorone (q.v.), which belongs 
 to the cyclopentenones, but is only dealt with in connection with 
 camphor. The oxime of methyl-cyclopentanone is split up by P 2 O 5 
 to the nitrile of hexylenic acid C 5 H 9 CN, with p-methyl-pyridine as a 
 by-product (C. 1899, II. 947). Cp. the similar behaviour of other 
 cyclic ketones. 
 
 A 2-Methyl-eyelopentanone, which also boils at i42-i44, has been 
 obtained from a-methyl-adipinic acid (B. 29, R. 1115). 2, 5-Dimethyl- 
 cyclopentanone, b.p. 146, from ac^-dimethyl-adipinic acid (B. 29,403). 
 2, 3, 3-Trimethyl-cyclopentanone from a, J8, p-trimethyl-adipinic acid 
 is related to camphoric acid (B. 33, 54). A large number of other 
 homologues of cyclopentanone have been prepared by method 70, p. 6, 
 from the anhydrides of the alkylated adipinic acids (C. 1908, II. 776). 
 
 l,3-Dimethyl-4, 5-diphenyl-eyelopentanone clH^CH^CHiCH^ 00 ' 
 m.p. 122, by reduction of dimethyl-anhydro-acetone-benzile with 
 HI and P. As an intermediate product we obtain 1, 3-Dimethyl- 
 4, 5-diphenyI-A 4 -cyelopentenone, m.p. 122 (C. 1905, 1. 172). 
 
 Methyl-cyelopentenone CH 3- c ^cH CH'' b ' p ' I57 ' in wood oiL 
 Oxime, m.p. 128 (B. 27, 1538). 
 
 Phenyl-eyclopentenone c 6 H 6 c/^ 2 ~ |P* 2 , m.p. 84, from phenacyl- 
 acetone (q.v.) with dilute NaOH. Oxime, m.p. 147 (B. 41, 194). 
 
 P TJ /- PTT \ 
 
 Diphenyl-cyclopentenolone,a^y^o-ac^owe6^n^7^^ 6 ^:^T^^>CO, 
 
 m.p. 149, from benzile (q.v.) and acetone. By condensation with 
 other ketones, such as methyl-ethyl-ketone and dibenzyl-ketone, 
 several more such ketone alcohols, of the cyclopentene series, have 
 been formed; from benzile and laevulinic acid (Vol. I.) we obtain similarly 
 a Diphenyl-eyelopentenolone-acetic acid or anhydro-benzile-laevulinic 
 acid (C. 1899, II- I0 5 I '> I 9 OI > II. I 3 I J I 93> I- 5^9). An isomeric 
 VOL. II. C 
 
ORGANIC CHEMISTRY 
 
 diphenyl-cyclopentenolone 65 7^> CO ' m -P- J 7 6 ' is ob ~ 
 
 v-'giricL-' \_/( vJJbjLj / 
 
 tained by the action of concentrated SO 4 H 2 upon dibenzal-acetone, 
 which is oxidised by potassium permanganate to benzile, and desyl- 
 acetic acid (q.v.). With HI both isomeric compounds are reduced to 
 1, 2-Diphenyl-cyelopentane (B. 37, 1133). 
 
 Hexachloro-cyclopentenones 00 ' m ' p> 28 ' b ' p ' 80 I56 ' and 
 
 ^^J'Nco, m.p. 92, b.p. 75 148, by oxidation with Cr0 3 , from the 
 CCl CCi2' 
 
 corresponding a-oxy-acids, obtained from benzene derivatives, like 
 o-amido-phenol and pyro-catechin (B. 24, 926 ; 25, 2697). For the 
 action of NH 3 upon these ketones, see C. 1898, I. 607. 
 
 1,2-Diketo-pentamethylene co'Ir^ 2 /^ 2 ' m> P- 56 ' P roduced b y 
 ketone splitting of the i,2-diketo-pentamethylene-3, 5-dicarboxylic 
 ester. The diketone has acid qualities. In accordance with the 
 
 desmotropic formula of a Cyclopentenolone c^^cH 2 /* 01 * 2 ' ^ forms 
 salts and reacts with acetyl chloride, benzoyl chloride, and phenyl 
 cyanate (B. 35, 3201). 
 
 Chlorine easily acts upon diketo-pentamethylene, with formation 
 of 3-Chloro-l, 2-diketo-pentamethylene, m.p. 139. Chlorinated 1,2- 
 diketo-pentamethylenes are also formed in a manner analogous to the 
 chlorinated cyclopentenones, from benzoyl derivatives, like phenol, and 
 chloranilic acid. From potassium chloranilate with chlorine and water 
 
 we obtain: ^'^'"/CO, m.p. 125 (B. 25,848). Starting from 
 
 CO.CH.C1/ 
 
 resorcin, Tetraehloro-diketo-R-pentene QZco/ >CCl2 ' m<p ' ^' b-p<27 
 148, was obtained (B. 24, 916 ; 25, 2225). 
 
 The primary disintegration products of the benzene derivatives 
 serving as basic products in these reactions are often chlorinated ketonic 
 acids. Thus,in the last case, from resorcin the acid CC1 3 .CO.CC1 : CC1CC1 2 
 COOH, perchlor-acetyl-crotonic acid, in which the ring completion to 
 the keto-pentamethylenes is then carried out by heating with con- 
 centrated sulphuric acid (B. 26, 513). In a similar manner it has 
 been found possible to convert the j8, 8-dibromo-laevulinic acid 
 CH 2 Br.COCHBr.CH 2 .COOH by means of fuming sulphuric acid 
 
 CBr CO X 
 into two : Dibromo-diketo-R-pentene || >CHBr, m.p. 99, and 
 
 CH CO /'*. 
 
 CH CO. 
 
 * m.p. 137 (A. 294, 183). 
 
 Methyl-triketo-pentamethylene co/ (CHa) ~SS m -P- Il8 > from 
 
 \CH 2 - CO 
 
 oxalic ester, and methyl-ethyl-ketone, by method 46 (p. 4) (B. 39, 
 1336). 
 
 By analogy, we have from dibenzyl-ketone : 
 
 Diphenyl-triketo-pentamethylene, oxalyl-dibenzy I- ketone 
 
 C \CH(C 6 H 5 ) Co' m ' P> I39 ' On heatin S> U transposes itself into 
 isoxalyl-dibenzyl-ketone, the lactone of an acyclic acid (B. 27, 1353 ; 
 A. 284, 245). 
 
PENTACARBOCYCLIC COMPOUNDS 19 
 
 Pentaketo-pentamethylene is the leuconic acid (q.v.) produced by 
 oxidation of croconic acid (q.v.). Both compounds are dealt with 
 among the oxy-benzo-quinones in connection with rhodizonic acid. 
 
 4. ALDEHYDES AND EXTRA-CYCLIC KETONES. Cyelopentane-alde- 
 hyde C 5 H 9 CHO, an oil with a penetrating odour, resembling valeralde- 
 hyde, has been obtained by the action of dilute SO 4 H 2 on methylene- 
 cyclopentane-glycol (q.v.). Semicarbazone, m.p. 123. 
 
 A'-Cyclopentenaldehyde 2 ~ : V.CHO, an unstable liquid, smell- 
 
 Cri 3 Crl 2 / - 
 
 ing like benzaldehyde, formed easily by condensation of the dialdehyde 
 of adipinic acid (Vol. I.). Also from the nitroso-chloride of methylene- 
 cydopentane by rejection of HC1 and splitting of the initially formed 
 oxime with dilute acids. 
 
 l-Methyl-2-aeetyl-pentamethylene C 5 H 8 (CH 3 )(COCH 3 ), b.p. 170, 
 from its carboxylic acid. 
 
 Acetyl-A '-cyclopentene 'Hcn / CCOCH3 ' b -P- I 73-i74 
 distinctly of benzaldehyde. Its oxi'me, m.p. 91, is generated by HC1 
 rejection from the nitroso-chloride of ethylidene-cyclopentane. 
 
 l-Methyl-2-acetyl-A 1 -cyclopentene ^ 2 "~ 3v )c.cocH 3 , b.p. 191. 
 
 CH 2 -Crl a - f 
 
 Oxime, m.p. 85, generated from the e-diketonane by Na ethylate. 
 Oxidised with MnO 4 K it yields y-acetyl-butyric acid. The inter- 
 mediate formation of a i,6-diketone is also, probably, a step in the 
 formation of : 
 
 Pentamethyl - acetyl - cyclopentene 
 
 2io-230, by reduction of the mesityl oxide (Vol. I. ; C. 1897, II. 579). 
 Concerning similar ring completions of i,6-diketones to cyclopentene 
 derivatives, see C. 1899, I. 21 ; 1909, I. 119). 
 
 1-Acetyl-eyelopentanone ^T^V HCOCH 3> b -P-s 75, by method 
 
 L/rl 2 CJbi^/ 
 
 4c, p. 5, from e-keto-oenanthylic acid. By heating with alcoholic Na 
 ethylate the ring is easily split again (C. 1909, II. 119). 
 
 By attaching cyclopentanone to benzal - aceto - phenone, by 
 means of alcoholic caustic soda we obtain the diketone 
 
 CH:lco!> CH - CH <cgcOC,H 5 ( B - 35 ' '445). 
 
 5. CARBOXYLIC ACIDS. Cyclopentane-carboxylie acid, b.p. 214, 
 smells of sweat ; 2-Methyl-eyclopentane-earboxylie acid, b.p. 219; 2, 5- 
 Dimethyl-eyclopentane-carboxylic acid, three stereo-isomeric forms: 
 m -P- 75-77> m.p. 26-3o, and m.p. 49-5o : 
 
 :H 2 .CH 2 \ C CH 2 .CH(CH 3 )\ CHCOOH CH 2 .CH(CH 3 )\ CHCOOH 
 
 CH 2 .CH 2 / CH 2 .CH 2 _ _/ CH 2 .CH(CH 3 )/ 
 
 These acids have been obtained from the cyclic malonic esters : 
 
 obtained from the corresponding alkylene dibromides by method 5 (p. 5) 
 (B. 26, 2246 ; 27, 1228 ; 34, 2565). 
 
 Cyclopentane-carboxylie acid has been prepared from the chloro- 
 
20 ORGANIC CHEMISTRY 
 
 cyclopentane with Mg and CO 2 , and from the corresponding a-oxy-acid. 
 The 2-methyl-cyclopentane-carboxylic acid has been obtained from the 
 corresponding a-acetyl-carboxylic acid. 
 
 3-Methyl-cyclopentane-carboxylic acid, b.p. 15 116, [a] D --5*89, 
 from the iodide of 3-methyl-cyclopentanol with Mg and CO 2 (B. 35, 
 2690). Isomeric with this is cyclopentane-acetic acid C 5 H 9 .CH 2 COOH, 
 by disintegration of the condensation product of iodo-cyclopentane 
 with Na-malonic ester (B. 29, 1907). 
 
 Cyclopentane-1, 2-diearboxylic acid is known in two modifications. 
 The cis-form forms an anhydride, and is generated by heating the 
 cyclopentane-i,2-tetracarboxylic acid obtained by method 6 (p. 5), or 
 from trimethylene bromide with sodium-malonic ester (B. 18, 3246 ; 
 C. 1901, II. 1264). 
 
 1, 3 - Cyclopentane - tetracarboxylic acid, produced in a similar 
 manner, yields, on heating, Cis-eyelopentane-1, 3-dicarboxylie acid, m.p. 
 121 (anhydride, m.p. 161), which on heating with HC1 is partly trans- 
 posed into the trans-acid, m.p. 88 (C. 1898, II. 770). 
 
 Cyclopentane-1, 2, 4-tricarboxylic acid C 5 H 7 (COOH) 3 is obtained by 
 the splitting of I, 2, 4-cyclopentane-hexacarboxylic ester, which is 
 formed by method 6 (p. 5), by the action of Br upon pentane-i, 3, 5- 
 hexacarboxylic ester (C. 1900, I. 802). 
 
 Cyelopentene-earboxylie acid C 5 H 7 .COOH, m.p. 120, from the 
 corresponding aldehyde with Ag 2 O (C. 1898, II. 761). 
 
 Cyclopentene-1, 2-dicarboxylic acid CH ^cH 2 -CcooH' m>p ' I78 ' 
 from aa 1 -dibromo-pimelinic acid by the action of Na alcoholate (see also 
 p. 5). Also from 1, 2-dibromo-cyclopentane-i, 2-dicarboxylic acid, 
 obtained by bromination of cyclopentane-dicarboxylic acid, by treat- 
 ment with alcohol, and KI. The acid easily adds 2Br ; by melting 
 with potash it is disintegrated to adipinic acid (B. 28, 655). 
 
 Bis-cyclopentadiene-earboxylie acid was mentioned above in connec- 
 tion with cyclopentadiene. 
 
 Cyclopentane-acetic acid C 5 H 9 CH 2 COOH, b.p. 226-23O, has 
 been obtained by transposition of cyclopentanol-acetic ester with 
 HBr and reduction of the compound produced. Amide, m.p. 145 
 (A. 353, 304). 
 
 Several a, j8-unsaturated acids are obtained by rejection of water 
 from the oxy-acids dealt with below. 
 
 Cyelopentsne-acetie acid (C 5 H 8 ) : CHCOOH, m.p. 52, b.p. 13 128- 
 130; Methyl-cyclopentene-acetic acid (CH 3 C 5 H 7 ) : CHCOOH, b.p. n 
 
 128 ; Cyclopentene-propionic acid (C 5 H 8 ) : cS** m.p. 108. 
 
 \UUUJtl 
 
 On dry distillation these acids expel CO 2 and pass into cyclopentene- 
 hydrocarbons with semicyclic double linking ; see Methylene-cyclo- 
 pentane (A. 365, 273 ; C. 1902, I. 1222). By nuclear synthesis from 
 laevulinic ester with Na alcoholate a Methyl-eyclopentadiene-carboxyl- 
 propionic acid CH^H^CH^^) has been obtained _ which 
 
 at 218 gives off CO 2 , and melts, forming at first methyl-cyclo- 
 pentadiene-propionic acid C 5 H 4 (CH 3 )(CH 2 CH 2 COOH), m.p. 65, and 
 then methyl-ethyl-cyclopentadiene C 5 H 4 (CH 3 )(CH 2 CH 3 ), b.p. 135. 
 These substances resemble cyclopentadiene in their behaviour 
 (B. 36, 944). 
 
PENTACARBOCYCLIC COMPOUNDS 21 
 
 Camphoric acid, i-methyl-2-dimethyl-cyclopentane-i, 3-dicarbo- 
 xylic acid, is dealt with under camphor (q.v.). 
 
 6. ALCOHOL - CARBOXYLIC ACIDS. a-Oxy-eyclopentane-earboxylie 
 acid ^ Ha ~~ ; H 2\c/ c a H , m p ^^ from cyc lopentanone CyH and HC1 
 
 CHg CH 2 / \OH 
 
 (A. 275, 333),' yields by reduction pentamethylene-carboxylic acid. 
 
 1-Methyl-a-amido-cyclopentane-carboxylie acid CH 3 .C 5 H S (NH 2 ) 
 COOH, m.p. 299 (B. 39, 1728). Hexaehloro-a-oxy-eyclopentene- 
 
 carboxylic acid 2 ~ aCH ' S enerated from chlorinated cyclo- 
 
 hexene-i, 2-diketone with NaCO 3 or sodium acetate. On heating 
 it passes into an isomeric acid (B. 23, 824). Both acids, boiled with 
 water, yield perchloro-indone (q.v.) (A. 272, 243). Triehloro-eyclo- 
 pentene-dioxy-carboxylie acid %&* ]^ 2 )>c<( 2H , by the action of 
 chlorine on alkaline phenol solution (B. 22, 2827). 
 
 1,1-Cyclopentanol acid ester ^SX^cooc^' b 'P' I0 5- 
 107, by condensation of cyclopentanone and bromacetic ester by 
 means of zinc. In the same manner we obtain 3-Methyl-l, 1-cyclo- 
 pentanol-acetic ester C 5 H 7 (OH)(CH 2 COOC 2 H 5 ), b.p. n 9o-92 ; 1,1- 
 Cyclopentanol-propionic ester C 5 H 8 (OH)CH(CH 3 )COOC 2 H 5 ; 1, 1- 
 Cyclopentanol-isobutyric ester C 5 H 8 (OH)C(CH 3 ) 2 COOC 2 H 5 , b.p. n 108- 
 
 ii3- 
 
 7. KETONE-CARBOXYLIC ACIDS. 2-Keto-pentamethylene-earboxylic 
 ester CH 2 .CH(CO 2 R)\ CO) from a ^ p i n i c ester by method 40, p. 4 ; this 
 
 CH 2 .CH 2 - / 
 
 ester may be regarded as a carbocyclic derivative of. aceto-acetic 
 ester, and shows its typical reactions (Vol. I.). With Na alcoholate 
 and methyl iodide it yields l-Methyl-2-keto-pentamethylene-carboxylic 
 ester, b.p. 22 108, and by ketone splitting, keto-pentamethylene. By 
 acid splitting, adipinic acid is regenerated. With amyl nitrite and 
 Na ethylate, a-oximido-adipinic ester is produced. 
 
 4-Methyl-2-keto-pentamethylene-carboxylic ester from j5-methyl- 
 adipinic ester (A. 317, 27, etc. ; C. 1908, I. 1169). 
 
 Keto-pentamethylene-3,4-dicarboxylic acid CO \CH 2 CHCO 2 H' b>p ' 
 189, by condensation of aconitic ester and Na-malonic ester, and 
 subsequent disintegration (B. 26, 373). 
 
 Keto-pentamethylene-2, 3-dicarboxylic ester C 
 
 b.p. 18 166, obtained from butane-i, 2, 4-tricarboxylic ester by method 
 4 (p. 4). On saponification it expels CO 2 , and passes into : 
 
 Keto-pentamethylene-3-carboxylic acid, CH 2 /^ ~5^V r m -P- 
 
 \Crl a Crl.COOH 
 
 65 (C. 1908, II. 1781). 
 
 A Phenyl-keto-pentamethylene-dicarboxylie acid has been prepared 
 by condensation of 2 - phenyl - 1, 3, 4 - butane - tricarboxylic ester 
 (A. 315, 219). 
 
 A Trimethyl-keto-pentamethylene-dicarboxylic ester, obtained from 
 dimethyl-butane-tricarboxylic ester by condensation with Na and 
 methyl iodide, possibly contains an atomic group similar to that of 
 camphoric acid (C. 1900, II. 332). 
 
22 ORGANIC CHEMISTRY 
 
 l-Imino-2-eyano-eyelopentane 2 ~ =NH > m -P- X 47> P r - 
 
 Ci 2 ^tz - ' 
 
 duced by intramolecular condensation of adipinic dinitrile with Na 
 ethylate. Similarly, 2-Imino-3-cyano-cyclopentane-l-carboxylic ester 
 
 CH 2 CH!CO ) R)/ >C=NH> m ' p * I:r 9' 50 ' is obtained by the action of 
 sodium cyanacetic ester upon I, i-cyano-trimethylene-carboxylic ester 
 where an intermediate production of ac^-di-cyanadipinic ester must 
 be assumed. On treatment with acids we obtain in succession : 
 3-Cyano-2-keto-pentamethylene-carboxylicester,b.p. 18 i72-i74,Cyano- 
 
 cyclopentanone 2 ^ CO ' b -P- 22 9 an(i ' nna %> cyclopentanone 
 
 (C. 1909, II. 14). 
 
 Several 1, 2-diketo-pentamethylene-carboxylic acids have been 
 obtained by method 46 (p. 4), by condensation of oxalic ester with 
 esters of the glutaric acid series, and similar acids, e.g. 1, 2-Diketo- 
 
 pentamethyIene-3,5-dicarboxylie ester cocH(COJR)) CH2 (B ' 35 ' 
 3206), and the corresponding methylated and phenylated ester in the 
 4-position. Some interest attaches to the ester of 4, 4-Dimethyl- 
 
 1, 2-diketo-pentamethylene-3, 5-dicarboxylic acid o CH(CO 2 H)^ C(CH3)2 ' 
 which has been made to pass in succession into apocamphoric acid, 
 and dimethyl-pentamethylene-dicarboxylic acid, by replacement of 
 the keto-oxygen atoms by hydrogen (A. 368, 126). 
 
 By similar syntheses we obtain from oxalic and tricarbullylic 
 ester : 1,2- Diketo - pentamethylene - 3, 4, 5 - tricarboxylic ester ; from 
 oxalic acid acetone-dicarboxylic ester : 1, 2, 4-Triketo-pentamethy- 
 lene-3, 5-diearboxylie ester (C. 1897, II. 892 ; B. 29, R. 1117). 
 
 2 - Methyl - 1 - acetyl - pentamethylene - carboxylic acid 
 
 CH^CH^>KcoOR 3 ' obtained b y method 5 (P. 5), is an extracylic 
 ketone-carboxylic ester (B. 21, 742). 
 
 A special group is formed by some substances, in which a five- 
 membered ring includes a three-membered ring, the so-called bicyclo- 
 pentanes. By condensation of aa r dibromo-p-dimethyl-glutaric ester 
 with Na-malonic ester a dimethyl-keto-bicyclopentane-tricarboxylic ester 
 is formed, through the intermediary of a Dimethyl-trimethylene- 
 dicarbo-malonic ester : 
 
 COOR COOR COOR 
 
 /CHBr _, rH s r /C - CH(COOR) 2 _ , rH . r /C - CH.COOR 
 - 
 
 COOR COOR COOR 
 
 The tricarboxylic ester is changed by successive rejection of 
 2COOR into Dimethyl-keto-bicyclopentane-di-and-monocarboxylic acid 
 (CH 3 ) 2 C<^H(COOH, and (CH3)2C /C(COOH).CH 2 In ^ ^^ 
 
 acid the trimethylene ring is broken up with formation of 2-Dimethyl- 
 4-keto-pentamethylene-carboxylic acid (B. 35, 2126 ; B. 42, 2770). 
 
 D. Heptacarbocyclic Compounds. 
 
 These substances have lately acquired additional importance 
 through their relations with alkaloids and terpenes, as well as the 
 
HEPTACARBOCYCLIC COMPOUNDS 23 
 
 so-called isophenyl-acetic acid. The frequently easy transformation 
 of heptacarbocyclic compounds into benzene derivatives is worthy of 
 note. Synthetically, most of the suberane derivatives have been 
 obtained by starting from suberone (cp. A. 275, 356). 
 
 Suberane, heptamethylene, cycloheptane 2 '^5 2 '^5 2 ^ CH 2> b.p. 117, 
 
 Orl2.OjT-2.Lx rig/ 
 
 generated by reduction of suberyl bromide or iodide. By bromine 
 and Al bromide suberane is converted into penta-bromo-toluol (q.v.) ; 
 by heating with HI, into methyl-cyclohexane and hexa-hydro-toluol 
 (B. 27, R. 47). 
 
 Ethyl-suberane C 7 H 13 .C 2 H 5 , b.p. 163, from zinc ethyl and suberyl 
 bromide. Two molecules of suberyl bromide and sodium yield di- 
 suberyl C 7 H 13 .C 7 H 13 , b.p. 291 (A. 327, 70). 
 
 Suberene, cycloheptene ^'^S 2 '^2 2 ^> CH 2 b.p. 114, obtained from 
 
 L-.rl.v_<.H.2.v_/.rl2/ 
 
 suberyl iodide with alcoholic potash. Also from suberylamine 
 by treatment with suberyl-trimethyl-ammonium hydroxide, and 
 distillation of the latter (A. 317, 218). Combines with Br to form 
 a dibromide. 
 
 AMttethyl-suberene 2! 1 1 ^ CCH 3 b -P- I 3^> from methyl- 
 
 U.H.g.L/.H^'L'.H^' 
 
 suberol on heating with potassium bisulphate. On oxidation with 
 MnO 4 K it yields c-acetyl-capronic acid. Nitroso-chloride, m.p. 106 
 (A. 345, 139). Isomeric with this hydrocarbon is : 
 
 Methylene-cycloheptane 2 '^5 2 2 / c =CH " b -P- W, obtained bv 
 
 L/rl2.L/rl2.Ori2/ 
 
 distillation of suberene-acetic acid. Nitroso-chloride, m.p. 81; 
 MnO 4 K oxidises to glycol (C 6 H 12 ) : C(OH)CH 2 OH, m.p. 50, which, 
 on further action, passes into oxy-suberane-carboxylic acid and into 
 suberone (A. 345, 146). 
 
 Cycloheptadiene, heptamethylene - terpene, hydro-tropilidene 
 
 ;** 2 \CH 2 , b.p. 121, by distillation of the quaternary ammonium 
 
 Crl : Cri.Crl 2 / 
 
 bases generated by the complete methylation of the various amino- 
 cycloheptenes (see below), produced partly by synthesis and partly by 
 disintegration of tropin. Combines with Br to a i, 4-dibromide, which, 
 on heating with quinolin, rejects 2HB and becomes : 
 
 Cycloheptatriene, tropilidene ^' | en/ 01 * 2 ' b ' p ' Il6 ' A ' 317j 2Q ^ '' 
 the dibromide of the latter passes into benzyl bromide on heating to 
 100 with HBr (B. 31, 1544). 
 
 Suberyl-aleohol, cycloheptanol, C 7 H 13 .OH, b.p. 184, is formed 
 besides suberyl-pinacone by reduction of suberone with Na and 
 alcohol ; by strong reduction with HI, suberyl-alcohol is converted 
 into hexahydro-toluol (B. 30, 1216). Chloride, b.p. 174 ; bromide, 
 b.p. 40 101"; iodide, D 15 1-572. Suberylamine, C 7 H 13 .NH 2 , b.p. 169, 
 by reduction of suberone oxime, or from suberane-carboxyl amide 
 with KOBr (B. 26, R. 813 ; A. 317, 219). 
 
 Methyl-suberol (C 6 H 12 ) : C(OH)CH 3 , b.p. i83-i85, from suberone 
 withMg(CH 3 )I. 
 
 Cycloheptenol-ethyl ether, C 7 H n .OC 2 H 5 , b.p. 174, from suberene 
 dibromide with alcoholic potash. 
 
 Suberyl-methylamine (C 7 H 13 ).CH 2 NH 2 , b.p. i93-i95, from the 
 
24 ORGANIC CHEMISTRY 
 
 amide of suberane-acetic acid with Br and alkali. Nitrous acid gives 
 suberyl-carbinol, and azealol (A. 353, 327). 
 
 A 2 -Amino-eyeloheptene 2 ' 2 '^5 2 5 CH - NH 1S > b.p. 166, from A 2 - 
 
 Crl 2 .Crl : Crl / 
 
 cycloheptene-carboxylic amide with KOBr, yields on methylation 
 A 2 -dimethyl-amino-cycloheptene C 7 H n .N(CH3) 2 , b.p. 188. this is 
 also produced from suberene dibromide with dimethylamine, and 
 shows positive isomerism with the two methyl-tropanes interpreted 
 as A 3 - and A 4 -dimethyl-amino-cycloheptene, produced by disin- 
 tegration of the alkaloid tropin (A. 317, 204 seq.). 
 
 Suberone [cycloheptanone] ^S 2 ~~^S 2 ~ S 2 V> b -P- l8o > smells of 
 
 C11 2 Crl 2 L/.hi 2 / 
 
 peppermint. From distillation of Ca suberinate. Passes on oxidation 
 into pimelinic acid. Condenses like adipin-ketone with benzaldehyde 
 into a dibenzal form, m.p. 108 (B. 29, 1600). Suberone oxime 
 C 7 H 12 (NOH), m.p. 23, b.p. 230, is transposed by concentrated 
 H 2 SO 4 into -heptolactame (see Vol. I.) Semicarbazone, m.p. 164. 
 
 AVMethyl-suberenone 2 -^ 2 '2^c.CH 3 , b.p. 2oo-205. Its oxime 
 
 C-rl 2 . C/H 2 .GH.'X 
 
 has been obtained from the nitroso-chloride of A 1 -methyl-suberene by 
 rejection of HC1 (A. 345, 145). 
 
 Suberane-aldehyde 2 '^ 2 ^ H2 \CH CHO, an oil smelling strongly 
 
 CH 2 .CH 2 .CH 2 / 
 
 of benzaldehyde, from the glycol of methylene-cycloheptane by the 
 action of dilute H 2 SO 4 (A. 345, 149). 
 
 A^Suberene-aldehyde $2 2 '^S 2 '^T : ^C.CHO also smells strongly of 
 
 O-H. 2 .OH 2 .C/H 2 / 
 
 benzaldehyde. It has been obtained from the nitroso-chloride of 
 methylene-suberane by withdrawal of HC1, and splitting of the oxime 
 thus generated with acids. Silver oxide oxidises it to suberane- 
 carboxylic acid. 
 
 Suberane-carboxylic acid, cycloheptane-carboxylic acid, C 7 H ]3 CO 2 H, 
 b.p. 15 139. Amide, m.p. 195, has been obtained synthetically from 
 Suberane-1, 1-diearboxylic acid, the ester of which is formed to a slight 
 extent from hexamethylene bromide and Na-malonic ester (B. 27, 
 R- 735). Suberane-carboxylic acid is also obtained from suberyl 
 bromide with Mg and CO 2 in ether, and by reduction from the various 
 cycloheptene, heptadiene, and heptatriene carboxylic acids. With 
 Br and P it yields a-Bromo-suberane-carboxylic acid, m.p. 93, which, 
 by rejection of HBr, gives : 
 
 A^Cycloheptene-earboxylie acid C 7 H n COOH, m.p. 52. Amide, 
 m.p. 126. This acid is also obtained, by heating with caustic alkali, 
 from the isomeric A 2 -Cyeloheptene-earboxylic acid, m.p. 19 ; amide, 
 m.p. 158. Both acids have also been obtained, together with some 
 other isomers, by the reduction of cycloheptatriene-carboxylic acids 
 or their dihydrobromides (A. 317, 234). 
 
 Cycloheptadiene-carboxylie acid C 7 H 9 .COOH, m.p. 78, identical 
 with hydro-tropilidene-carboxylic acid, a disintegration product of 
 hydro-ecgonidin (q.v.). 
 
 Cycloheptatriene - carboxylic acids, tropilidene - carboxylic acids, 
 isophenyl-acetic acids, C 7 H 7 .COOH : a, m.p. 71 (amide 129); ]8, m.p. 
 56 (amide 98) ; y, liquid (amide 90) ; 8, m.p. 32 (amide 125). The 
 isomerism of these acids is governed by the various positions of the 
 
HEPTACARBOCYCLIC COMPOUNDS 25 
 
 three double linkages. With HBr they form mono-, di-, and even 
 trihydrobromides, but on energetic treatment with HBr they are 
 transposed into the dihydrobromide of p-toluylic acid. They have 
 been obtained : (i) by disintegration of the alkaloid ecgonin, which 
 therefore, like the related tropin, contains a seven-member carbon 
 ring (B. 31, 2498) ; (2) by transposition of the pseudo-phenyl-acetic 
 acid or norcaradiene-carboxylic acid (C. 1900, I. 811). The latter, 
 generated from benzene and diazo-acetic ester (Vol. I.) by rejection 
 
 of N, has the formula ^H=CH^CH/ CHC H ' and re P resents the 
 combination of a six-member ring with a trimethylene ring, and 
 therefore a condensed nucleus such as is dealt with below. Similar 
 combinations are probably also contained in the terpene-ketones 
 carvone (q.v.) and eucarvone (q.v.), of which the latter passes by reduction 
 into dihydro-eucarvone, which should be regarded as methyl-gem- 
 
 dimethyl-cycloheptenone ^ ca \^^^^ t (B. 31, 2068). 
 
 1 - Oxy - suberane - earboxylie acid, suberyl-glycolic acid, C 7 H 12 
 (OH)CO 2 H-f-JH 2 O, melts anhydrously at 79. From suberone 
 with HCy and HC1 ; also from a-bromo-suberane-carboxylic acid 
 with baryta water (B. 31, 2505). With PbO 2 it may be oxidised 
 again completely to suberone (B. 31, 2507). With concentrated HC1 
 or PC1 5 it passes into chloro-suberanic acid, m.p. 43 (A. 211, 117 ; 
 B. 31, 2004). 
 
 a-Amido-suberane-carboxylie acid C 7 H 12 (NH 2 )COOH, m.p. (an- 
 hydrous) 3o6-307 (B. 39, 1730). 
 
 1-Oxy-suberane-acetic acid, cydoheptanol - acetic acid 
 
 C.H 12 >C<^ COOH ; the esters of this acid (methyl, b.p. 12 1410-145; 
 
 ethyl, b.p. n 134) are obtained from suberone and brom-acetic esters 
 with Zn or Mg. On heating with potassium bisulphate, the esters 
 split off H 2 O and pass into esters of Suberylene- acetic acid 
 C 6 H 12 > C=CHCOOH, b.p. 17 159, which, on distillation at atmo- 
 spheric pressure, decomposes into CO 2 and methylene-cycloheptane 
 C 6 H 12 >C=CH 2 (H. 314, 156; B. 35, 2143). By transposition with 
 halogen hydrides, oxy-suberane-acetic acid yields bromo- and iodo- 
 suberane-acetic acid, m.p. 69 and 81, which by reduction pass into 
 Suberane-acetic acid (C 7 H 13 )CH 2 COOH, b.p. 19 165. Amide, m.p. 148 
 (A. 353, 301). 
 
 E. Octocarbocyclic Compounds. 
 
 The doubly unsaturated hydrocarbons of cyclo-octane have lately 
 attracted particular interest on account of their relations to rubber. 
 Pseudo-pelletierin, the alkaloid closely related to tropin and tropinone, 
 also contains the eight-member carbon ring. It forms the basis for 
 the majority of the compounds here to be described. 
 
 Cyelo-octane 
 
 D 4 0-849, nas been obtained by reduction of jS-cyclo-octadiene with 
 Ni and H. 
 
 A-'-Cyclo-octadiene , b ' P ' 16 39 ' 4 
 
 generated together with small quantities of an isomeric, bicyclic 
 
26 ORGANIC CHEMISTRY 
 
 hydrocarbon during distillation of the quaternary ammonium base 
 obtained by thorough methylation of N-methyl-granatanin, a reduction 
 product of pseudo-pelletierin (q.v.) (cp. the analogous preparation of 
 cycloheptadiene from tropane). The cyclo-octadiene is a mobile oil 
 of penetrating odour, the vapour of which is poisonous. It polymerises 
 with extraordinary facility even in the cold, and explosively on heating. 
 This produces a dicyclo-octadiene (C 8 H 12 ) 2 , m.p. 114, and a polycyclo- 
 octadiene (C s H 12 )a., an amorphous mass with a m.p. above 300. Ozone 
 transforms the cyclo-octadiene into a di-ozonide C 8 H 12 O 6 , which, with 
 water, decomposes with formation of succinic dialdehyde. With 
 HBr it combines to form a dihydrobromide C 8 H 14 Br 2 , b.p. 12 150, 
 from which, by the action of caustic potash or quinolin, a /?- Cyclo- 
 octadiene, b.p. 143, is obtained, which is isomeric with the original 
 compound. It has an agreeable odour and shows no tendency to 
 polymerisation (B. 40, 957). 
 
 According to Harries, Para rubber is a polymerisation product of 
 
 [CH 3 .C CH 2 CHo CH ~| 
 II .It 
 
 CH CH 2 CH 2 C.CHgJ-r 
 
 is probably, therefore, also the intermediate product in the poly- 
 merisation of isoprene (Vol. I.), which has lately acquired technical 
 importance (B. 38, 3985). 
 
 As from suberinic acid we obtain suberone, so by distillation of cal- 
 
 /->TT PfT PW f*O 
 
 cium azelainate we obtain Azelaone, cydo-octanone * 2 ! ~ , , 
 
 but only in small quantities. It is an oil with an odour closely 
 resembling suberane, b.p. I95-I97, m.p. 25-26. Semicarbazone, 
 m.p. 85. On oxidation with MnO 4 K the ketone yields cork acid. 
 By reduction with Na and alcohol it passes into the corresponding 
 
 alcohol called Azelaol CH 2 -CH 2 CH 2 CH H ' b ' p ' l88 ' This is also 
 obtained by the action of nitrous acid upon suberyl-methylamine 
 (B. 31, 1957 ; C. 1899, II. 182 ; A. 353, 328). 
 
 Tricyclo-octane-, dimethyl-, and diphenyl-trieyclo-oetane are sup- 
 posed to be represented by the hydrocarbons derived from the diolefin- 
 carboxylic acids (vinyl-acrylic acid, sorbinic acid, and cinnamenyl- 
 acrylic acid) on heating with baryta water, polymerisation, and 
 rejection of CO 2 (B. 40, 146). These formulae are, however, not yet 
 sufficiently well established. 
 
 F. Nonocarbocyclic Compounds. 
 
 Compounds with a ring of nine carbon atoms have only been 
 obtained quite recently. But the physical data indicate that these 
 substances are not yet obtainable in a state of purity. 
 
 Cyclononanone ^H' CH" CH' CH' / CO ' b ' p ' 17 9 5 ~97' D 4 22 ' 5 
 0-8665, is obtained in minute quantities on distilling sebazinic acid 
 with slaked lime. Semicarbazone, m.p. 105. Na reduces it to : 
 
 Cyclononanol ^'Zcn 2 CH' CH 2 / CHOH> b ' p ' 13 97~ I0 5> which > 
 through the corresponding iodide, can be transformed into : 
 
 the fundamental hydrocarbon of this series (B. 40, 3277, 3876). 
 
BENZENE DERIVATIVES 27 
 
 II. -HEXACARBOCYCLIC COMPOUNDS 
 
 THE chemistry of hexacarbocyclic compounds is incomparably 
 greater and more richly developed than the chemistry of the ring 
 systems dealt with in the preceding chapter. Hexacarbocyclic 
 compounds may be divided into three classes : 
 
 A. Mononuclear aromatic substances, or benzene derivatives. 
 
 B. Mononuclear hydro-aromatic substances. This class contains 
 the terpene group and the camphor group. 
 
 C. Polynuclear aromatic substances. The fundamental hydro- 
 carbons of this group contain (a) several benzene nuclei connected 
 direct or by aliphatic hydrocarbon residues ; or (b) two or more nuclei 
 are so combined with one another that two carbon atoms are common 
 to each (twin nuclei, condensed nuclei). 
 
 CTT /"^ TT V /"* "1 
 
 6^5 ^e^sXpTj W 
 
 C 6 H 5 C.H 5 / 2 C.1 
 
 Diphenyl Diphenyl-methane Triphenyl-methane Tetraphenyl-methane 
 
 C 6 H 5 CH 2 C 6 H 5 CH C a H 6 C 
 
 II III 
 
 C 6 H 5 CH 2 C 6 H 5 CH C 6 H 5 C 
 
 Dibenzyl Stilbene Tolane 
 
 /CH% C.H 4X 
 
 Indene Fluorene Naphthalin Anthracene, etc. 
 
 With each of these hydrocarbons numerous derivatives of all 
 kinds may be associated, thus forming an unlimited field. Many of 
 these bodies, especially naphthalin and its derivatives, give rise to 
 hydro-compounds. These are, however, not dealt with as a separate 
 fourth class, but always in connection with the unhydrogenated 
 derivatives of the hydrocarbons in question. 
 
 A. Mononuclear Aromatic Substances or Benzene Derivatives. 
 
 By the name " aromatic " compounds we designate substances 
 which are mostly obtained from aromatic oils and resins, and which 
 differ in general from the fatty bodies or methane derivatives by 
 various peculiarities, especially a greater content of carbon and a 
 well-marked " aromatic " odour. Our theoretical conceptions con- 
 cerning the constitution of these compounds are mainly derived from 
 the benzene theory formulated in 1865 by Kekule. It may be 
 summarised in the following theses (cp. Kekule, Lehrbuch der org. 
 Chemie, ii. 493 ; A. 137, 129) : 
 
 1. " All aromatic compounds are derived from a nucleus consisting 
 of six carbon atoms, the simplest combination of which is benzene 
 C 6 H 6 . They are produced by the replacement of the H atoms by 
 other atoms or groups of atoms (side groups). They all show the 
 specific benzene characteristics, contrasting with the methane 
 derivatives, and should be called ' benzene derivatives.' ' 
 
 2. " Benzene has a symmetrical constitution. Each carbon atom 
 is joined to an H atom to a carbin group CH. As in the case of the 
 polymethylene derivatives, no differences can be traced between the 
 
28 ORGANIC CHEMISTRY 
 
 several C or H atoms, and isomerisms of derivatives are therefore 
 only found in the case of two or more side groups." 
 
 3. " The structure of the benzene nucleus resembles the methane 
 derivatives in that the six atoms, or CH group, are alternately bound 
 by single and double links, thus making a closed ring-formed chain of 
 six carbon atoms, according to the scheme : 
 
 C=C 
 C=C C=C C=C or C C 
 
 1 ' V/ 
 
 / \ 
 
 which can also be expressed by a regular hexagon. The fourth valence 
 of the carbon atoms is attached in benzene to an H atom, and in its 
 derivatives to other atomic groups." 
 
 Historical. The first to invent a structural formula for an aromatic 
 compound was Archibald Scott Couper, who in 1858, in his work on 
 salicylic acid (C.R. 46, 1107), represented it by the formula: 
 
 C H 2 
 C H 
 
 fC H 
 1C o 
 
 OH <= 8 > 
 
 c |0 2 
 1 O 
 
 OH 
 
 In 1861 J. Loschmidt published a pamphlet called Chemisette 
 Studien (Wien, Gerold), with new graphic formulae for 360 substances, 
 among them being 180 aromatic compounds. Loschmidt charac- 
 terises the aromatic acids as substances with incomplete nuclei, having 
 incompletenesses in eight places. The simplest of these nuclei is 
 C 6 VI , for which he brings the six carbon atoms close together : 
 
 (Scheme 181 of Loschmidt) 
 
 thus obtaining a formula as contained in Couper's salicylic acid 
 formula. He figures the C atoms by means of circles touching where 
 there is single binding, and intersecting where there is plural binding. 
 He prefers, however, a " stratification " of the six C atoms to their 
 
 Allyl JL_ ^^^J^J " Benzo1 nucleus 
 
 (Scheme 68). ^~~Y]fll (Scheme 182). 
 
 " condensation," and imagines the nucleus as a double allyl nucleus 
 (scheme 182). For allyl, Loschmidt had considered the trimethylene 
 formula (scheme 68). Loschmidt, however, left the question of 
 nuclear constitution in suspense, his constructions being independent 
 
BENZENE DERIVATIVES 
 
 29 
 
 of it. He says : " We assume for the nucleus C 6 VI the symbol 184 " 
 a larger circle " and treat it as if it were a hexavalent element." 
 
 Loschmidt then gives graphic formulae for many benzene deriva- 
 tives, some of which are given here : 
 
 o 
 
 C, VI (184). 
 
 C 6 H 6 (i 86). 
 
 C e H 6 CH 3 (197). 
 
 Of these, 185 represents phenol, and 197 toluol. 
 
 Loschmidt had therefore already formed the first thesis of Kekule's 
 benzene theory. He says nothing about the equivalence of the six 
 benzene H atoms. It was, in fact, excluded on the assumption that the 
 benzene molecule consisted of two stratified allyl rings, since in scheme 
 182 the free valencies are unequally distributed, as shown by the 
 points of scheme 181. Kekule, on the other hand, places the structure 
 of the nucleus into the foreground, and derives from it the equivalence 
 of the six H atoms and the explanation of the isomerism of the substi- 
 tution products. 
 
 GENERAL SURVEY OF THE BENZENE DERIVATIVES. 
 
 The benzene derivatives can be derived from the replacement of 
 the H atoms of benzene in the same manner as the aliphatic substances 
 are derived from methane. Benzene derivatives with side chains 
 containing carbon may be built up from benzene and brought back 
 to benzene by eliminating the side chains. Benzene derivatives differ 
 from methane derivatives in the stability of the benzene nucleus. 
 Thus oxidation usually stops short at the benzene nucleus, and so 
 does reduction in general, leading finally, as a rule, to cyclohexane 
 derivatives or hexahydro-benzene derivatives, without any splitting 
 of the benzene ring. Reduction therefore connects benzene deriva- 
 tives with cyclohexane derivatives (p. 2). 
 
 Those benzene derivatives which are solid at ordinary temperatures 
 are often distinguished for their ease of crystallisation, and this is a 
 great aid to their experimental investigation. 
 
 The H of benzene is easily replaced by the halogens and the 
 groups nitro NO 2 and snip ho SO 3 H : 
 
 Chloro-benzene . 
 
 Nitrobenzene 
 
 Benzol-sulpho-acid 
 
 C a H 5 Cl 
 
 C 6 H 5 N0 2 
 
 C 6 H 5 S0 3 H 
 
 C 6 H 4 C1 2 
 
 C 6 H 4 (N0 2 ) 2 
 
 C 6 H 4 (S0 3 H) 2 
 
 C 6 H 3 C1 3 C 6 C1 6 
 
 C 6 H 3 (N0 2 ) 3 
 C 6 H 3 (S0 3 H) 3 
 
 According as to whether one, two, three, or more H atoms of benzene 
 are replaced, we distinguish mono-, di-, tri-, tetra-, penta-, or hexa- 
 derivatives of benzene. 
 
 Specially characteristic for the benzene derivatives is the formation 
 of nitro-bodies through the direct action of HNOg, whereas the aliphatic 
 bodies are generally oxidised or decomposed by it. 
 
 Reduction of the nitro-bodies produces the amido-compounds : 
 
 Amido-benzene (aniline) C 6 H 5 NH 2 C 6 H 4 (NH 2 ) 2 C 6 H 3 (NH 2 ) 3 . 
 
3 o ORGANIC CHEMISTRY 
 
 As intermediate products of reduction, we have the so-called azo- 
 compounds, while the action of nitrous acid upon amido-compounds 
 produces the diazo-compounds ; both classes of bodies are only excep- 
 tionally present in the aliphatic series (Vol. I.). 
 
 On replacing the H in benzene by hydroxyl we obtain the phenols, 
 comparable to the alcohols : 
 
 C 6 H 6 OH C 6 H 4 (OH) 2 C 6 H 3 (OH) 3 
 
 Phenol (carbolic acid) Dioxy-benzol Trioxy-benzol. 
 
 Like the tertiary alcohols, the phenols contain the group C.OH 
 linked to three C valences, and they cannot therefore form any corre- 
 sponding aldehydes, ketones, or acids by oxidation. 
 
 The benzene nucleus weakens the basic properties of the amido- 
 group and imparts acid properties to phenyl-hydroxyl. It possesses 
 a more negative character than the residues of aliphatic hydrocarbons. 
 
 By the entry of monovalent paraffin, olefin, and acetylene residues, 
 the so-called homologous benzene hydrocarbons are derived, both 
 saturated and unsaturated : 
 
 C 6 H 6 C 6 H 5 CH 3 C 6 H 4 (CH 3 ) 2 C 6 H 5 CH 2 .CH 3 CeH^H,, etc. 
 
 Benzolene Methyl-benzol Dimethyl-benzol Ethyl-benzol Propyl-benzol 
 (toluol) (xylol) 
 
 C 6 H 5 CH=CH 2 C 6 H 5 C=CH, etc. 
 
 Vinyl-benzol (styrol) Acetylene-benzol. 
 
 In these hydrocarbons the benzene nucleus preserves the specific 
 properties of benzene. Its hydrogen is easily replaced by halogens 
 and by the groups NO 2 and SO 3 H. But the side chains behave just 
 like the hydrocarbons of the fatty series ; its hydrogen can be replaced 
 by halogens, but not (through action of concentrated HNO 3 or H 2 SO 4 ) 
 by the groups NO 2 or SO 3 H. According as to whether the halogens 
 (or other groups) enter into the benzene residue or into the side chains, 
 we obtain different isomers : 
 
 Chloro-toluol C 6 H 4 C1.CH 3 Benzyl chloride C 6 H 5 .CH 2 C1 
 
 Dichloro-toluol C 6 H 3 C1 2 .CH 3 Chloro-benzyl chloride C 6 H 4 C1.CH 2 C1 
 
 Benzal chloride C 6 H 5 CHC1 2 . 
 
 The halogen atoms in the benzene residue are firmly held, and usually 
 incapable of a double substitution, while the halogen atoms in the 
 side chains act just as in the methane derivatives. 
 
 If in the side chains H is replaced by hydroxyl, we get the true 
 alcohols of the benzene series : 
 
 C 6 H 5 .CH 2 OH C 6 H 5 .CH 2 .CH 2 OH C ' 
 
 Benzyl-alcohol Phenyl-ethyl-alcohol Tolyl-alcohol 
 
 the primary ones of which form aldehydes and acids by oxidation : 
 
 CHO 
 Benzaldehyde Phenyl-acetaldehyde Tolyl-aldehyde. 
 
 The acids in which COOH is joined to the benzene nucleus may 
 also be produced by direct introduction of carboxyl into the benzene, 
 or by oxidation of the homologues of benzene : 
 
1SOMERISM OF THE BENZENE DERIVATIVES 31 
 
 C 6 H 5 .C0 2 H C 6 H 4 (C0 2 H) a C 6 H 3 (CO 2 H) 3 
 
 Benzol-carboxylic acid Benzol-dicarboxylic acid Benzol-tricarboxylic acid 
 
 /-> TU 3 r TJ /TJ m TJ r W '"32 
 
 C6H *\CO?H C 6 H 5 .CH 2 .C0 2 H C H 3\ C O 2 H 
 
 Toluylic acid Phenyl-acetic acid Mesitylenic acid. 
 
 In these acids, as well as the alcohols and aldehydes, the H of the 
 benzene residue is also replaceable by halogens and by the groups 
 NO 2 , SO 3 H, OH, etc. 
 
 In the above discussion benzene was regarded as the foundation. 
 The various benzene derivatives with aliphatic side chains were all 
 regarded as benzene substitution products. It is obvious that this 
 view may be reversed. Then the benzene derivatives with a single 
 side chain appear, e.g. as phenyl substitution products of the aliphatic 
 substances, as exemplified by the following terminology : 
 C 6 H 5 CH 3 Phenyl-methane C 6 H 5 CH 2 CH 2 OH Phenyl-ethyl-alcohol 
 
 C S H 5 CC1 3 Phenyl-chloroform C 6 H 5 CH 2 CHO Phenyl-acetaldchyde 
 
 C 6 H 5 CH 2 OH Phenyl-methyl-alcohol C 6 H 5 CH 2 COOH Phenyl-acetic acid 
 C 6 H 5 COOH Phenyl-formic acid C 6 H 6 CH 2 CH 2 CO 2 H Phenyl-propionic acid. 
 
 ISOMERISM OF THE BENZENE DERIVATIVES. 
 
 Proof of the equivalence of the six H atoms of Benzene. If in benzene 
 one H atom is replaced by another atom or atomic group, any compound 
 so obtained is only found in one modification ; there is but one chloro- 
 benzene, one nitro-benzene, one amido-benzene, one toluol, one benzoic 
 acid ; so the compounds 
 
 C 6 H 5 C1 C 6 H 5 .N0 2 C 6 H 5 .NH 2 C 6 H 5 CH 3 C 6 H 5 .CO 2 H 2 etc. 
 
 are only known in one modification. The six H atoms of benzene 
 are equivalent, like the four H atoms of methane (Vol. I.). Benzene 
 has a symmetrical structure. 
 
 Historical. The proof of the equivalence of the six hydrogen atoms 
 of benzene was given in 1869 simultaneously and independently by 
 W. Korner and A. Ladenburg (B. 2, 274, 1869 ; 7, 1684 ; 8, 1666). 
 
 i. Both investigators used the transformation of the three monoxy- 
 benzoic acids into the same phenol, in order to prove the equivalence 
 of the three positions taken by the carboxyl in benzene. 
 
 According to Korner, it follows from the reduction of the three 
 monochloro-benzoic acids with Na amalgam to the same benzoic acid. 
 
 The equivalence of a fourth H atom follows, according to Laden- 
 burg, from the transformation of phenol into bromo-benzol, and from 
 this into benzoic acid. Ladenburg's proof of the equivalence of four 
 H atoms of benzene may therefore be represented as follows : 
 a b c d e f 
 
 C 6 (OH) H H H H H 
 
 C 6 Br H H H H H 
 
 C 6 (C0 2 H) H H H H H 
 
 C 6 (C0 2 H) OH H H H H 
 
 C 6 (CO 2 H) H OH H H H 
 
 C 6 (CO 2 H) H H OH H H 
 
 Phenol 
 
 | Bromo-benzol 
 
 .!. Benzoic acid t 
 
 I Ortho-oxy-benzoic acid 
 
 Meta-oxy-benzoic acid 
 Para-oxy-benzoic acid 
 
 Korner deduced the equivalence of the fourth H atom with the 
 three H atoms replaced by carboxyl in the three monoxy- and the 
 
32 ORGANIC CHEMISTRY 
 
 three monochloro-benzoic acids from the following facts : Para-oxy- 
 benzoic acid corresponds to para-nitraniline (Arppe), which is con- 
 vertible into either paranitro-chloro- or paranitro-bromo-benzene. 
 
 Paranitro-chloro-benzene, by replacement of the nitro-group by 
 Br, gives the same parabromo-chloro-benzene as is obtained on sub- 
 stituting Cl for the nitro-group in paranitro-bromo-benzene. Hence 
 the two H atoms which are replaced in para-nitraniline by the nitro- 
 and amido-group respectively, are equivalent, as are also the H atoms re- 
 placed by hydroxyl and carboxyl respectively in para-oxy-benzoic acid. 
 
 a bed e f 
 
 C 6 OH H H CO 2 H H H Para-oxy-benzoic acid 
 C 6 NO 2 H H NH 2 H H Para-nitraniline 
 
 ^C 6 N0 2 H H Cl H H > C 6 Br H H Cl H H 
 
 C 6 N0 2 H H Br H H > C 6 Cl H H Br H H 
 
 This proves the equivalence of four H atoms of benzene. 
 
 2. Each hydrogen atom of benzene has two pairs of H atoms 
 arranged symmetrically with respect to it, i.e. so that the replacement 
 of either of the two H atoms of a pair by the same atom or the same 
 atomic group leads to the same compound. 
 
 Korner proves this symmetry as follows for two H atoms. The 
 volatile nitro-phenol which is convertible into pyrocatechin, and there- 
 fore belongs to the same series as salicylic acid, may, by replacing two 
 H atoms by one Br atom and one nitro-group respectively, be converted 
 into the same bromo-nitro-ortho-nitro-phenol as is obtained by intro- 
 ducing two nitro-groups into ortho-bromo-phenol : 
 
 abcdef abcdef 
 
 Cl OH Br 2 H H H H^ H N > H N H * 
 
 b=f. 
 
 It is therefore clear that in phenol there are two H atoms sym- 
 metrical to hydroxyl, and that it is immaterial which of them is repre- 
 sented by bromine, and which by a nitro-group. But if this symmetry 
 is established for one pair of H atoms, it is also established for the 
 second pair, since the symmetry of the first pair is unthinkable without 
 the symmetry of the second pair. Hence follows the equivalence of 
 all the H atoms of benzene. 
 
 The symmetrical arrangement of two H-atom pairs in benzene can 
 also be proved as follows. For one pair, b and /, this thesis follows 
 from the formation of the same ortho-amido-benzoic acid out of two 
 different nitro-bromo-benzoic acids, obtained by the nitration of meta- 
 bromo-benzoic acid (Hiibner and Petermann, A. 149, 129 ; 222, in ; 
 Ladenburg, B. 2, 140) : 
 
 a b c d e f 
 C COjjH H Br H H H Meta-bromo-benzoic acid 
 
 C, C0 2 H N0 2 Br H H H 
 C 6 CO 2 H H Br H H NO 2 
 C 6 C0 2 H NH 2 H H H H 
 
 v-Meta-bromo-ortho-nitro-benzoic acid* 
 as-Meta-brorao-ortho-nitro-benzoic acid * 
 Ortho-amido-benzoic acid 
 
 C CO 2 H H H H H NH 2 Ortho-amido-benzoic acid < ' 
 
 Hence ab =af. 
 
 * The designations v and as are dealt with below in connection with the 
 tri-derivatives. 
 
ISOMERISM OF THE BENZENE DERIVATIVES 33 
 
 For the second pair the proof is furnished by the formation of 
 the same meta-bromo-toluol from two bromine compounds (Wro- 
 blewsky, A. 192, 213 ; 234, 154), in which bromine replaces two 
 different H atoms, which therefore are symmetrical with the H atom 
 replaced by the methyl group of toluol : ac=ae. 
 
 a b c d e f 
 
 C, CH 3 H H NH(COCH 3 ) H H 
 C 6 CH 3 H Br NH(COCH 3 ) H H 
 
 C, C0 2 H H Br H H H 
 
 a b c d e f 
 
 C 6 CH 3 H Br NH(COCH 3 ) NO 2 H 
 
 C, CH 3 H Br NH 2 H H v C 6 CH 3 H Br H NO, H 
 
 C 6 CH 3 H Br H H H | C, CH 3 H H H NH, H 
 
 C 8 CH 3 H H H Br H 
 
 By oxidation this bromo-toluol passes into the same meta-bromo- 
 benzoic acid which above served as a basis for the proportion of v- 
 and rts-meta-brom-ortho-nitro-benzoic acid. Hence it follows that 
 bromine in the last proof replaces two H atoms other than those re- 
 placed by the amido-group in ortho-amido-benzoic acid, and that in 
 benzene there are not one but two pairs of H atoms in symmetrical 
 position with respect to an H atom. This establishes the equivalence 
 of the six pairs of H atoms. (See also Ladenburg, B. 10, 1218.) 
 
 For the second pair of H atoms the proof of symmetry may be given 
 as follows. The ortho-amido-benzoic acid obtained in two ways (see 
 above) may be converted into the same oxy-benzoic acid, viz. salicylic 
 acid, which on nitrogenation gives two different mononitro-salicylic 
 acids. By heating the ethyl ethers of these two nitre-salicylic acids 
 with ammonia the ethoxyl groups can be replaced by the amido- 
 groups, and, from the nitro-amido-benzoic amides, the free nitro- 
 amido-benzoic acids may be obtained, which with nitrous acid and 
 alcohol are converted into the same nitro-benzoic acid. Since this 
 nitro-benzoic acid, obtained from two different nitro-salicylic acids, 
 yields a (meta) amido-benzoic acid different from the amido-benzoic 
 acid from which the salicylic acid was obtained, and since it yields a 
 (meta) oxy-benzoic acid different from salicylic acid, it follows that 
 there are two further H atoms symmetrically placed with respect to 
 the H atom replaced by the COOH group : 
 
 a bcdef a bcde f 
 
 ! C a CO 2 H NH 2 H H H H = C 6 CO 2 H H H H H NH 2 , 
 
 |C 6 CO 2 H OH H H H H = C 6 CO 2 H H H H H OH 4- 
 
 |C 6 CO 2 H OH NO 2 H H H~~ ~-^C 6 CO 2 H H H H NO 2 OH 
 
 TC 6 CO 2 H NH 2 NO 2 H H H I C 6 CO 2 H H H H NO 2 NH 2 
 
 tie, C0 2 H H N0 2 H H H = | C. CO 2 H H H H NO 2 H 
 
 JC 6 CO 2 H H NH 2 H H H = j C 6 CO 2 H H H H NH 2 H 
 
 1C, C0 2 H H OH H H H = I C CO 2 H H H H OH H 
 
 For the third oxy-benzoic acid, para-oxy-benzoic acid, only one 
 position therefore remains, viz. the para position, which in benzene 
 is only possible once. 
 
 The equivalence of the six H atoms has lately been proved by 
 Noelting in a very simple manner (B. 37, 1027). 
 
 In amido-benzol or aniline the amido-group is easily replaced by 
 bromine, and the latter by the CH 3 group with the aid of methyl iodide 
 VOL. II. D 
 
34 
 
 ORGANIC CHEMISTRY 
 
 and sodium. In the toluol thus produced the methyl group therefore 
 takes up the same position as the amido-group does in aniline. From 
 the toluol we obtain by nitrogenation three isomeric nitro-toluols, 
 and from these by reduction three toluidins, which by acetylation, 
 oxidation, and the elimination of the acetyl group can be transformed 
 into three different amido-benzoic acids. These all yield, by rejection 
 of CO 2 , an amido-benzol identical with the initial product, which 
 proves the equivalence of four H atoms : 
 
 
 a 
 
 b 
 
 c 
 
 d 
 
 e 
 
 f 
 
 |C 6 
 
 NH 2 
 
 H 
 
 H 
 
 H 
 
 H 
 
 H 
 
 r* 
 
 ^6 
 
 CH 3 
 
 H 
 
 H 
 
 H 
 
 H 
 
 H 
 
 V.P 
 
 -^v^ 8 
 
 CH 3 
 
 NH 2 
 
 H 
 
 H 
 
 H 
 
 H 
 
 -^C 6 
 
 CH 3 
 
 H 
 
 NH 2 
 
 H 
 
 H 
 
 H 
 
 *c. 
 
 CH 3 
 
 H 
 
 H 
 
 NH 5 
 
 H 
 
 H 
 
 f 
 
 
 
 
 H< 
 
 
 
 
 H 
 
 
 a 
 
 b 
 
 c 
 
 H > 
 
 -c 6 
 
 C0 2 H 
 
 NH 2 
 
 H 
 
 H 
 
 -c e 
 
 C0 2 H 
 
 H 
 
 H 
 
 H > C 6 
 
 CO 2 H 
 
 H 
 
 H 
 
 a=b=c=d. 
 
 
 
 
 d e 
 H II 
 NH 2 H 
 NH, H 
 
 The proof of the second thesis (that one H atom has two other H 
 atoms placed symmetrically to it) is based upon one of the nitro- 
 toluols just referred to, in which the CH 3 group takes up position a. 
 This, on reduction, yields a toluidin from which, by nitrogenation of 
 its acetyl compound and saponification, four isomeric nitro-toluidins 
 are obtained. By elimination of the amido-group these yield four 
 nitro-toluols. Now, it is found that of these two are identical with 
 each other and two with the initial nitro-toluol, which proves the 
 symmetrical position of two pairs of H atoms : 
 
 ! C 6 CH 3 N0 2 H 
 
 i C 6 CH 3 NH 2 H 
 
 >C 6 CH 3 NH 2 H 
 
 -^C 6 CH 3 NH 2 H 
 
 >C 6 CH 3 NH 2 NO 2 H 
 
 >C CHo NH, H 
 
 d 
 H 
 H 
 
 e 
 H 
 H 
 
 f 
 H 
 
 
 
 
 
 
 
 H 
 
 H 
 
 N0 2 - 
 
 
 
 
 
 
 
 H 
 
 N0 2 
 
 H a 
 
 b 
 
 c 
 
 d 
 
 e 
 
 f 
 
 H 
 
 H 
 
 H ^C 6 CH 3 
 
 H 
 
 N0 2 
 
 H 
 
 H 
 
 H 
 
 N0 2 
 
 H 
 
 H > Cg CH 3 
 
 H 
 
 H 
 
 N0 2 
 
 H 
 
 H 
 
 ab = af ac=ae. 
 
 The six H atoms of benzene are therefore equivalent, and, since there 
 are two pairs of symmetrically placed H atoms to each single H atom, 
 a di-substitution product of benzene can only occur in three isomeric 
 modifications. 
 
 PRINCIPLES OF LOCATION FOR BENZENE SUBSTITUTION PRODUCTS. 
 The equivalence of the six H atoms in benzene is expressed by the 
 
 hexagon diagram, in which the mutual linking of the C atoms may for 
 the present be disregarded. It is obvious that of each bi-derivative 
 
BENZENE SUBSTITUTION PRODUCTS 35 
 
 C G H 4 X 2 obtained by replacement of two H atoms three modifications 
 are possible and that their isomerism depends upon the relative 
 position of the two new groups entering the benzene scherrte. This 
 is called isomerism of position or geometrical isomerism (Vol. I. p. 32). 
 And in fact three modifications are known of most di-derivatives, but 
 not more than three. Thus there are three 
 
 r w / 
 C ' H < 
 
 OH r /Br r /NH 2 r /OH 
 
 OH C ' H *\N0 2 C ' H <NH 2 C ' H <N0 2 
 
 Dioxy-benzols Bromo-nitro-benzols Dianiido-benzols Nitro-phenols 
 
 T / 
 C ' H < 
 
 C0 2 H rw /CH 3 PTT /C0 2 H 
 
 OH C ' H4 \CH3 C H *\CH 3 'C0 2 H 
 
 Oxy-benzoic acids Dimethyl-benzols Toluylic acids Phthalic acids, etc. 
 
 The three modifications of each of these compounds can be con- 
 verted into the corresponding modifications of the others. If, therefore, 
 we have determined the relative positions of the replacing atoms or 
 atomic groups in the three modifications of one of these bodies, it is 
 known for all the others, and they can be converted into the three 
 modifications of the first body by straightforward reactions free from 
 intramolecular atomic displacements. The relative positions of re- 
 placing groups have been determined in the case of several di- 
 substitution products, e.g. the three dibromo-benzols, the three 
 diamido-benzols, and the three phthalic acids. In this way a 
 basis has been obtained for arranging the other di-substitution 
 products in three series, designated as ortho-, meta-, and para-series 
 respectively. 
 
 In the ortho-compounds two adjoining H atoms are replaced. If 
 the six H atoms of benzene are indicated by numbers or letters, and 
 any one of them by i or a, we see that there are two ortho-positions : 
 a, b=a, f, or i, 2=1, 6 ; b or 2 and/ or 6 are symmetrical to a or i. 
 The meta-compounds are produced by replacement of the atoms a, c 
 =a, e, or i, 3=1, 5, the positions c (3) and e (5) being symmetrical 
 to a (i). The ^am-compounds are produced by replacing the H atoms 
 a, d or i, 4. While, therefore, there are two equivalent places for the 
 ortho- and meta-positions, viz. 2 and 6, 3 and 5 respectively, the para- 
 position has only one location corresponding to i, viz. 4. 
 
 The location of the replacing groups in the di-derivatives is indi- 
 cated by prefixing ortho-, meta-, and para- to the compounds, abbreviated 
 into o, m, and p, or by prefixing the numbers [i, 2]-, [i, 3]-, [i, 4]- 
 enclosed in square brackets. The formulas are often represented by 
 writing the benzene ring as a hexagon and attaching the atoms or 
 atomic groups to its corners. Or, again, by introducing the location 
 figures between the benzene residue and the substitution groups : 
 
 OH OH OH 
 
 ^" - 10H 
 
 H H OH 
 
 Pyro-catechin Resorcin Hydroquinone 
 
 o-Dioxy-benzol m-Dioxy-benzol p-Dioxy-benzol 
 
 [i , 2]-Dioxy-benzol [i , 3]-Dioxy-benzol [i , 4J-Dioxy-benzol. 
 
36 ORGANIC CHEMISTRY 
 
 Among the principal representatives of the three isomeric series we 
 may put the following : 
 
 Ortho, [1,2] Meta, [1,3] Para, [1,4] 
 
 C 6 H 4 \ Salicylic acid Meta-oxy-benzoic acid Para-oxy-benzoic acid. 
 
 \CO 2 H 
 
 \CH 
 
 Phthalic acid Isophthalic acid Terephthalic acid. 
 
 C 6 H 4 / CH3 Ortho-xylol Iso-xylol Para-xylol. 
 
 CH 3 
 
 ^ 2 ** 
 CO 2 Jtl 
 
 LOCATION OF THE DI-DERIVATIVES. 
 
 The benzene hexagon indicates two chemically identical ortho- 
 derivatives, two chemically identical meta-derivatives, and a single 
 para-derivative, if we neglect the mutual linking of the six C atoms. 
 
 The first to indicate a way of experimentally determining the 
 location of the substituents in benzene multiple-substitution products 
 was W. Korner. In 1867 he propounded the opinion that a trioxy- 
 benzol, obtained from any of the three isomeric dioxy-benzols, must 
 necessarily be a I, 3, 4-trioxy-benzol (Bull. Acad. Roy. Belg. 2, 24, 
 166) . As the transformation of dioxy- into trioxy-benzols was attended 
 with difficulties, Korner replaced the dioxy-benzols by dibromo- 
 benzols, and for these he determined the absolute constitution, in 1874, 
 by conversion into tribromo-benzols (Gazz. Chim. Ital. 4, 305). Korner 
 nitrogenated the three dibromo-benzols. One of them gave two 
 mononitro-dibromo-benzols ; the second, three more ; and the last, one, 
 all different. These six mononitro-dibromo-benzols were then reduced 
 to the corresponding mono-amido-dibromo-benzols, and afterwards 
 transformed into the three tribromo-benzols. Korner showed that in 
 this last transformation the first dibromo-benzol yielded two different 
 tribromo-benzols ; the second, three different ones ; and the third, only 
 one tribromo-benzol. Korner concluded that the first dibromo-benzol 
 had the two Br in the ortho-positiou, the second in the meta-position, 
 and the third one in the ^wa-position. Thus the absolute position of 
 the bromine atoms in the three tribromo-benzols was determined and 
 the constitution of the six mononitro-benzols was cleared up. The 
 following diagrams illustrate this argument. For the sake of clearness, 
 the H atoms have been omitted. 
 
 Br 
 
 V 
 
 Br 
 Br 
 
 ft 
 
 Y N 
 
 Br 
 
 Br 
 
 Br Br 
 
BENZENE DI-DERIVATIVES 37 
 
 What may be called a reversal of this argument is found in 
 the process experimentally realised by P. Griers (B. 5, 192 ; 
 7, 1223). 
 
 There are six isomeric diamido-benzoic acids, and the diamido- 
 benzol generated by the rejection of CO 2 from two of these acids is the 
 0-compound, that which is generated from three of the six acids is the 
 /^-compound, and that which is generated from the sixth acid is the 
 ^-compound. 
 
 NH 2 NH 2 NH 2 
 
 i li f i 
 
 V NH 2 '^C 
 C0 2 H NH 2 
 
 NH 2 NH 2 
 
 NH 2 
 
 The constitution of benzene derivatives containing side chains is 
 produced by transformation into benzol-carboxylic acids. For the 
 three phthalic acids or benzol-dicarboxylic acids the constitution is 
 determined by the following facts (B. 4, 101) : 
 
 The phthalic acid obtained by oxidation of naphthalin is the [i, 2]- 
 or ortho-benzol-dicarboxylic acid. Naphthalin consists of two 
 benzene nuclei having two C atoms in common in the ortho- 
 positions. 
 
 By oxidation of nitro-naphthalin we obtain nitro-c-phthalic acid, 
 which can be converted into phthalic acid ; on oxidising the amido- 
 naphthalin obtained by reduction of nitro-naphthalin, we obtain 
 o-phthalic acid, the oxidation destroying, first the one, and then the 
 other, side of the naphthalin molecule. This determines the constitu- 
 tion of both the naphthalin and of phthalic acid as an o-dicarboxylic 
 acid of benzene : 
 
 N0 2 H 
 
 H/VNn 
 
 a-Amido-naphthalin Benzol-o-dicarboxylic acid 
 Phthalic acid. 
 
 The so-called isophthalic acid is benzol - m - dicarboxylic acid, 
 since it can be obtained by oxidation from isoxylol. Isoxylol 
 is m-dimethyl-benzol, as shown by its formation from mesitylenic 
 
38 
 
 ORGANIC CHEMISTRY 
 
 acid, the first oxidation product of mesitylene, or [i, 3, 5]-tri- 
 methyl-benzol : 
 
 CH 3 COH 
 
 CH 3 
 
 CH 3 
 
 H 
 
 Mesitylene 
 [x, 3, 53-Tnmetiiyi- 
 
 benzol 
 
 H 
 Mesitylenic acid 
 
 H 
 
 Isoxylol 
 
 [i,3]-Dimethy- 
 
 benzol 
 
 H 
 
 Isophthalic acid 
 Benzol-[i, 3]-di- 
 carboxylic acid. 
 
 The proof that mesitylene is really [i, 3, 5]-trimethyl-benzol is due 
 to Ladenburg, who showed that the three unreplaced H atoms of 
 mesitylene are equivalent (A. 179, 174) : 
 
 
 a 
 
 b 
 
 c 
 
 
 
 
 
 
 
 
 i C,(CH,), 
 
 H 
 
 H 
 
 H 
 
 
 
 
 
 
 
 
 4, C,(CH 3 ), 
 
 N0 2 
 
 NO, 
 
 H 
 
 
 a 
 
 b 
 
 c 
 
 
 
 
 4, C.(CH,), 
 
 N0 2 
 
 NH 2 
 
 H-i 
 
 > C 6 (CH 3 ), 
 
 NO, 
 
 H 
 
 H 
 
 
 
 
 4, Q(CH 3 ) 3 
 
 N0 a 
 
 NHCOCHa 
 
 H 
 
 ^ C 6 (CH 3 ) S 
 
 NH 2 
 
 H 
 
 H 
 
 
 
 
 4, C 4 (CH 3 )a 
 
 NO, 
 
 NHCOCHa 
 
 N0 2 
 
 if C 6 (CH,) 3 
 
 NHCOCH 3 
 
 H 
 
 H 
 
 a 
 
 b 
 
 c 
 
 4, C 9 (CH 3 ) 3 
 
 NO, 
 
 NH 2 
 
 NO 2 
 
 ^ C 6 (CH 3 ) 3 
 
 NHCOCHj, 
 
 NO 2 
 
 H or C,(CH S ) 3 
 
 NHCOCH 3 
 
 H 
 
 NO 2 
 
 4, C,(CH 3 ) 3 
 
 N0 2 
 
 H 
 
 N0 2 ^C 6 (CH 3 ) 3 
 
 NH, 
 
 NO 2 
 
 H or 1 C 6 (CH 3 ) 3 
 
 NH 2 
 
 H 
 
 NO 2 
 
 b=c 
 
 The above scheme clearly illustrates the argument. Mesitylene gives 
 dinitro-mesitylene, of which the NO 2 groups may replace the H atoms 
 a and b, and then in succession nitro-amido-, nitro-acetamido-, dinitro- 
 acetamido-, dinitro-amido-, and dinitro-mesitylene, identical with the 
 origin. Hence b and c are equivalent. The nitro-amido-mesitylene, in 
 which we assume the NH 2 group at b, yields mono-nitro-, mono-amido-, 
 mono-acetamido-, mono-acetamido-nitro-, and mono-amido-nitro- 
 mesitylene, identical with the first nitro-amido-mesitylene obtained by 
 reduction of dinitro-mesitylene. Hence a and b or a and c are equi- 
 valent ; but, since b and c are already proved to be equivalent, the 
 equivalence of the three unreplaced H atoms of mesitylene is proved. 
 Mesitylene is symmetrical; therefore its three methyl groups must 
 occupy the positions [i, 3, 5]. 
 
 For the third benzol-dicarboxylic acid, terephthalic acid, only the 
 i, 4-position remains, as may be proved as follows : Terephthalic acid 
 is derived from p-dimethyl-benzol, and this again from p-bromo- 
 toluol (through methyl iodide and Na). Now, p-bromo-toluol yields, 
 by oxidation, p-bromo-benzoic acid ; p-bromo-benzoic acid and 
 p-oxy-benzoic acid belong to the same series, for p-oxy-benzoic acid 
 originates in the same p-amido-benzoic acid through the diazo-com- 
 pound, through which p-bromo-benzoic acid may also be obtained. 
 But of p-oxy-benzoic acid we have already proved that its hydroxyl 
 group represents an H atom symmetrical to no other H atom of 
 benzene. 
 
 With the di-derivatives of benzene containing no carbon-bearing 
 radicles as substituents, the three phthalic acids have a genetic relation. 
 The three dinitro-benzols may be converted into nitro-amido-, bromo- 
 nitro-, brom-amido-, and dibromo-benzols on the one hand, and into 
 nitre-cyanic, nitro-carboxylic, amido-carboxylic, cyano-carboxylic, 
 
BENZENE DI-DERIVATIVES 39 
 
 and phthalic acids on the other hand, by reactions in which no intra- 
 molecular atomic displacements are observed (B. 18, 1492, 1496). 
 
 NO 2 _~ TT /NO 2 _^ r TT /NH 2 r /Br 
 
 - 
 
 r TT /N0 2 ~ TT /N0 2 ~ TT /NH 2 r TT /CN - TT /C0 2 H 
 
 C H <CN >C ' H <C0 2 H- >C H4 \C0 2 H- >C < H <\C0 2 H- ^'Vo.H 
 
 A further proof is furnished by the derivatives of the three isomeric 
 xylols. We have 
 
 from Metaxylol, 3 nitroxylols, xylidins, and xylenols 
 from Orthoxylol, 2 nitroxylols, xylidins, and xylenols 
 from Paraxylol, I nitroxylol. 
 
 from which the following positions may be ascertained : 
 
 [i, 3] meta- or isoxylol and isophthalic acid 
 [1,2] orthoxylol and phthalic acid 
 [1,4] paraxylol and terephthalic acid. 
 
 (B. 18, 2687.) 
 
 That in the ortho-compounds two neighbouring C atoms of the 
 benzene nucleus hold the side groups, is shown by their capacity for 
 simple reactions, in which a union of the side chains gives rise to 
 carbo- and, especially, hetero-cyclic condensation products (o-pheny- 
 lene-diamine, o-amido-phenol, o-amido-thiophenol, o-amido-benzalde- 
 hyde, o-phthalic acid, o-oxy-cinnamic acid, etc.). There are also 
 crystallographic reasons for supposing that the meta-compounds stand 
 between ortho- and /wra-compounds (Zeitschr. f. Kryst., 1879, 171 ; 
 B. 18, R. 148). 
 
 The hexagon scheme of benzene, therefore, not only represents 
 all the isomeric relations of benzene derivatives, but sheds light on 
 their chemical and physical behaviour. 
 
 ISOMERISM OF THE BENZENE POLY-SUBSTITUTION PRODUCTS. 
 
 When three or more H atoms are replaced in benzene, three cases 
 must be distinguished : The substituents are equal or different. In 
 the first case there are three possible isomers of the tri-derivatives, 
 such as C 6 H 3 (CH 3 ) 3 , with the positions 
 
 [i, 2, 3] [i, 2, 4] or [i, 3, 5]. 
 They are termed 
 
 adjoining [i, 2, 3] or v = vicinal 
 
 unsymmetrical [i, 2, 4] or as = asymmetric 
 
 symmetrical [i, 3, 5] or s =symmetric tri-derivatives. 
 
 For the tetra-derivatives with four equal groups C 6 H 2 X 4 there are 
 also three possible isomeric structures : 
 
 [i, 2, 3, 4] [i, 2, 4, 5] [i, 2, 3, 5]. 
 v s as 
 
40 ORGANIC CHEMISTRY 
 
 With five or six equal groups only one modification is possible ; there 
 is but one pentachloro-benzol C 6 HC1 5 , and only one hexachloro- 
 benzol C 6 C1 G . 
 
 If the substituent groups are unequal, the number of possible 
 isomers is much greater ; it is easily derived from the hexagon scheme. 
 Thus we have for the formula of dinitro-benzoic acid C 6 H 3 (NO 2 ) 2 COOH 
 six isomers : 
 
 [i, 2, 3] [i, 2, 4] [i, 2, 5] [i, 2, 6] [i, 3, 4] [i, 3, 5], 
 
 assigning position i to the carboxyl group. 
 
 The constitution of the poly-substitution products of benzene is 
 determined by their genetic relations to the di-substitution products 
 of known structure. 
 
 CONSTITUTION OF THE BENZENE NUCLEUS. 
 
 According to the benzene formula established by Kekule in 1865, 
 six C atoms are alternately simply and doubly linked into a closed 
 chain. This assumption gives a comprehensive picture of the whole 
 behaviour of the benzene derivatives : 
 
 1. It illustrates the synthetic formation of the benzene derivatives, 
 the condensed benzols, naphthalin, phenanthrene, etc. ; and is corro- 
 borated by all recent syntheses, such as that of a-naphthol from 
 phenyl-isocrotonic acid, etc. (see also B. 24, 3117). 
 
 2. It agrees with the splitting reactions of the benzene nucleus. 
 
 3. It explains, in a simple manner, how the ortho-derivatives on 
 account of the neighbouring position of two side groups are capable 
 of forming anhydrides and numerous derivatives founded upon an 
 ortho-condensation. The benzene formula also results clearly from 
 the ring formation of quinolin (A. 280, i). 
 
 4. The existence of three bivalent linkings explains in a simple 
 manner, without new hypotheses, the faculty for forming addition 
 products possessed by the benzene derivatives (p. 45). Such additions 
 do not, indeed, take place with the same ease as in the case of ethylene 
 linkings, in the methane bodies ; but aliphatic olefin compounds also 
 show gradual differences in powers of addition (see Allyl alcohol, 
 Vol. I.). 
 
 5. Several physical properties also indicate the existence, in benzene 
 bodies, of double linkings similar to those found in ethylene derivatives. 
 Thus, according to Briihl (B. 27, 1065), the refractivities show that in 
 benzene derivatives there are three ethylene linkings CH=CH (Vol. I.), 
 but in naphthalin five. The specific volumes of the benzene bodies 
 also seem to speak for the existence of three double linkings (Vol. I.). 
 
 Kekule's benzene formula does not, however, completely express 
 the symmetry of the benzene nucleus ; for it would indicate a differ- 
 ence in the ortho-derivatives [i, 2] and [i, 6], and they would have 
 to give rise to four di-derivatives each unless we follow Kekule" in 
 assuming oscillations of neighbouring carbon atoms (A. 162, 86 ; B. 5, 
 463 ; A. 279, 195). 
 
 Perhaps, during the formation of an ortho-derivative, a displace- 
 ment of the double linkings occurs when the substituting groups 
 approach two single-linked C atoms, so that what is formed is always 
 
CONSTITUTION OF THE BENZENE NUCLEUS 
 
 the di-derivative in which the substituent groups are attached to two 
 doubly linked C atoms. This would explain the easier complete oxi- 
 dation of the o-derivatives, in comparison with the corresponding m- 
 and p-derivatives. 
 
 It cannot be denied that the prediction of the existence of two 
 modifications of an ortho-substitution product instead of one con- 
 stitutes a weakness of Kekule's benzene formula. It must also be 
 remarked that the many analogies between the ortho- and para- 
 derivatives, in comparison with the meta-derivatives (see Quinone 
 and Quinone derivatives) , are not sufficiently expressed by this formula. 
 Still, we give it preference, in comparison with other benzene formulae, 
 because it gives a consistent view of the connection between aromatic 
 and aliphatic compounds. 
 
 Among other benzene schemes we may figure the diagonal scheme 
 of Claus (A), the prismatic scheme of Ladenburg (B t , B 2 , B 3 ), and the 
 centric scheme of Armstrong and von Baeyer (C). 
 
 A B, B 2 B, 
 
 V 
 
 Claus: 
 Diagonal scheme 
 
 Ladenburg : 
 Prismatic scheme 
 
 Annstrong-Baeyer : 
 Centric scheme. 
 
 According to formulae A and B there are no double linkings in the 
 benzene nucleus. The existence of nine univalent links was supposed 
 to be proved by the specific volume of the benzene compounds, 
 and especially by their heats of combustion ("Theory of Heats of 
 Formation," by J. Thomson, B. 13, 1808 ; 19, 2944). But, according 
 to more recent investigations, the specific volumes rather indicate the 
 existence of three double links in the benzene nucleus, and the 
 conclusions derived from the heats of combustion do not appear to 
 be irrefutable (Briihi, /. pr. Ch. 2, 49, 201). 
 
 The prismatic formula of Ladenburg " accounts for all the static 
 conditions of benzene," and illustrates the isomerisms of the benzene 
 derivatives. But it denies all double linkages such as are proved to 
 exist in the partly reduced nuclei of the di- and tetrahydro-addition 
 products ; it gives a spatial arrangement, of the four affinities of the 
 carbon atoms, having no analogy among the methane bodies; and, 
 according to its author, "it yields priority to Kekule's scheme for 
 all processes of formation and decomposition of benzene bodies" 
 (B. 23, 1010). 
 
 Although Claus's diagonal formula is consistent with isomeric 
 relations, and allows of any para- and ortho-additions (B. 20, 1422 ; 
 /. pr. Ch. 2, 49, 505), it arranges the four C affinities without analogy, 
 and assumes a peculiar central valency of a new kind. 
 
 Baeyer's new centric formula leaves the condition of the fourth C 
 valency indefinite, simply assuming that it exerts a centrally directed 
 pressure. In this way it returns to Kekule's scheme, which does not 
 profess to explain the linking of the fourth valency (B. 23, 1272 ; 
 24, 2689 ; A. 269, 145 ; B. 24, R. 728). 
 
42 ORGANIC CHEMISTRY 
 
 Thiele has lately made a different attempt to explain the required 
 symmetry of the benzene nucleus. He assumes that, in ordinary 
 double linkings, certain "residual valencies" remain, two of which 
 mutually saturate each other when the double linkings adjoin. On 
 assuming such a saturation of all the residual valencies of the three 
 ethylene links, the six C atoms are seen to be linked by six " inactive " 
 double links (A. 308, 213 ; 311, 194). 
 
 Some constitutional formulae for benzene are based upon stereo- 
 chemical considerations, such as Thomson's octahedral formula (B. 19, 
 2944), and especially the benzene model of Sachse (B. 21, 2530 ; Z.f. 
 physik. Ch. 11, 214; 23, 2062), as well as that of J. Loschmidt (Wien. 
 Akad. Ber. 1890, vol. 99, ii. p. 20). For later discussions of the 
 various stereo-chemical formulse, see B. 35, 526, 703 ; and C. 1902, 
 II. 350. 
 
 BENZENE RING FORMATIONS. 
 
 The nuclear synthesis reactions of aliphatic substances, in which 
 benzene rings are formed, are important mainly as joining aliphatic 
 and aromatic substances genetically. They will therefore be passed in 
 review, before dealing with the various classes of bodies, in the same 
 succession as that in which the initial bodies were dealt with in the 
 aliphatic series (Vol. I.). 
 
 1. CH 4 , methane, conducted through an incandescent tube, gives 
 benzene and other products. 
 
 2. 3CH = CH, acetylene, polymerises at a red heat to benzene. 
 
 3. 3CH = C.CH 3 , allylene, polymerises in SO 4 H 2 to [i, 3, 5]-/n- 
 methyl-benzol or mesitylene. 
 
 36. 3CH 3 .C=C.CH 3 , crotonylene, polymerises to hexamethyl- 
 benzol. 
 
 4. CC1 4 , perchloro-methane, and CC1 2 =CC1 2 , perchloro-ethylene, on 
 passing through an incandescent tube, give perchloro-benzol ; see also 
 perbromo-benzol. 
 
 5. 3CH^CBr, monobromo-acetylene, polymerises to [i, 3, $]-tri- 
 bromo-benzol. 
 
 6. C 6 H 13 I, hexyl iodide, gives with Cl iodide hexachloro-benzol ; with 
 bromine, hexabromo-benzol. 
 
 ya. (CH 3 ) 2 C : CH.CH 2 .CH 2 C(CH 3 ) :CH.CHO, geraniol or citral, gives 
 with potassium bisulphate [i, ^\-isopropyl-tohwl or cymol. 
 
 jb. CH 3 .CH 2 CH :C(CH 3 )CH :CH.COCH 3 , from methyl-ethyl-acrolein 
 and acetone, yields pseudo-cumol. 
 
 yc. (C 3 H 7 ).CH 2 CH : C(C 3 H 7 ).CH : CH.CO.CH 3 , from 2 mol. isovaler- 
 aldehyde and i mol. acetone, gives di-isopropyl-toluol (B. 28, R. 608). 
 
 8a. 3CH 3 COCH 3 , acetone, gives with SO 4 H 2 [i, 3, $}-trimethyl-benzol 
 or mesitylene. 
 
 8b. 3CH 3 CO.CH 2 CH 3 , methyl-ethyl-ketone, gives [i, 3, 5\-triethyl- 
 benzol. 
 
 8c. 3CH 3 CO.CH 2 CH 2 CH 3 , methyl-n-propyl-ketone, gives [i, 3, $}-tri- 
 n-propyl-benzol. 
 
 9. 6CO, carbon monoxide, combines with K on heating to potassium- 
 he xaoxy -benzol. 
 
 10. 3CH 3 CH 2 CH 2 COC1, butyryl chloride, is condensed by A1 2 C1 6 
 into triethyl-phoroglucin. 
 
BENZENE RING FORMATIONS 43 
 
 11. 3CH = C.CO 2 H, propiolic acid, polymerises in sunlight to 
 [i, 3, 5]-benzol-tricarboxylic acid or trimesinic acid. 
 
 12. 3NO 2 CH(CHO) 2 , nitro-malonic aldehyde, gives, on decomposi- 
 tion of its Na salt, sym. trinitro-benzol. 
 
 13. NO 2 .CH(CHO) 2 , nitro-malonic aldehyde, and CH 3 COCH 3 , 
 acetone, give p-nitro-phenol (B. 28, 2597 ; C. 1899, II. 609). 
 
 14. 3CH 3 .CO.CH==CHOH, oxymethylene-acetone or formyl-acetone, 
 condenses easily to [i, 3, S\-triacetyl-benzol C 6 H 3 (COCH 3 ) 3 . 
 
 150. 2CH 3 CO.CO.CH 3 , diacetyl, condenses with alkalies to p- 
 xylo-qninone or [2, $}-dimethyl-quinone. 
 
 156. 2CH 3 .CO.CO.CH 2 CH 3 , acetyl-propionyl, gives duro-quinone or 
 tetramethyl-quinone. 
 
 16. 3CH(OH)=CH.CO 2 C 2 H 5 , oxymethylene-acetic ester or formyl- 
 acetic ester, and their dimolecular condensation product, cumalinic 
 acid, condense easily to esters of the [i, 3, 5]-benzol-tricarboxylic acid 
 or trimesinic acid ; this is also obtained from a mixture of formic 
 and chloracetic acids with zinc (C. 1898, II. 472). 
 
 17. 4CH 3 COCO 2 H, pyro-traubenic acid, condenses on heating with 
 NaHO with rejection of oxalic acid and water to methyl-dihydro- 
 trimesinic acid, which passes easily into uvitinic acid with rejection 
 of CO 2 . 
 
 18. 2CHOCH 2 CH 2 COOH, j3-formyl-propionic acid, gives terephthalic 
 acid or p-benzol-dicarboxylic acid. 
 
 19. 2CH 3 CO.CHNa.CO 2 C 2 H 5 , sodium-acetic ester, and CHC1 3 , 
 chloroform, combine to oxy uvitinic ester or oxymethyl-isofrhthalic ester, 
 
 also obtained direct from methenyl-bisacetic ester cH/ CH ( c 2 C 2 H 5) COCH 3 
 
 ^ C(CO 2 C 2 H 5 )COCH 3 
 
 with Na alcoholate. 
 
 20. 2ROCOCH : CH.CH 2 COOR, glutaconic acid ester, unites under 
 the action of sodium ethylate, with rejection of one molecule of alcohol, 
 and acetic ester to form ^-oxy-iso-phthalic acid ester (B. 37, 2117). 
 
 21. CH 3 C:CH.CO.CH.COCH 3 dehydracetic addj ^^ orcin or ^ 5 _ 
 
 vJ \-^\_J 
 
 dioxy-toluol. 
 
 22. 2CH 3 .CO.CH 2 .CO.CO 2 C 2 H 5 , acetone-oxalic ester, is condensed 
 to oxy-toluylic acid ester. 
 
 2$a. CH 3 .CH 2 CH : C(CH 3 ).CH : C(COOR) 2 , from methyl - ethyl - 
 acrolei'n and malonic ester, yields with Na alcoholate oxy-mesitylenic acid. 
 
 236. (CH 3 ) 2 : CH.CH 2 .CH 2 .C(CH 3 ) : CH.CH : C(COOR) 2 , citralidene- 
 malonic ester, yields ^-isoamenyl-^-methyl-salicylic acid. 
 
 It is doubtful whether in the formation of mellithic acid or benzol- 
 hexacarboxylic acid C 6 (CO 2 H) 6 by the oxidation of charcoal or graphite 
 a synthesis occurs ; perhaps this reaction must be regarded as the 
 transformation of a molecule consisting of twelve C atoms. 
 
 On again surveying the reactions by which aliphatic bodies are 
 converted into benzene bodies by nuclear synthesis, we find that : 
 
 (1) Some saturated compounds, like methane and tetrachloro- 
 methane, yield the benzene ring by the action of heat (pyro-con- 
 densation). Many benzene derivatives, like benzene and the methyl- 
 benzols, simple amido- and oxy-benzols, are distinguished for their 
 constancy at high temperatures (see Coal-tar). 
 
 (2) During perchloration of many aliphatic compounds the occur- 
 
44 ORGANIC CHEMISTRY 
 
 rence of perchloro-benzol was observed. Hexyl iodide is transformed 
 particularly easily into perchloro- and perbromo-benzol. 
 
 (3) A large number of aliphatic acetylene compounds containing 
 a triply linked pair of C atoms, yield benzene derivatives by polymerisa- 
 tion of three similar molecules. A difficult polymerisation is that of 
 acetylene to benzene. Brom-acetylene is much more easily poly- 
 merised. Allylene and crotonylene require sulphuric acid, propiolic 
 acid, and sunlight for aromatic polymerisation. 
 
 The other aliphatic compounds above referred to, which may 
 condense themselves to aromatic substances (aromatic condensation), 
 contain carbon and oxygen in double linking. Many are ketones, 
 or they contain the oxy-methylene group. 
 
 (4) A direct addition reaction is exemplified by the manner in which 
 potassium hexa-oxy-benzol is formed from CO and K. 
 
 (5) Hydrolytic condensation is exemplified by the simple ring 
 formation in the transition of citral or geranial and other high-mole- 
 cular keto-olefins into cymol, pseudo-cumol, and di-isopropyl-toluol, 
 as well as the condensation of di-hydro-acetic acid to orcin, with 
 liberation of CO 2 . 
 
 (6) The condensation of acetone, methyl-ethyl- and methyl-n- 
 propyl-ketone to [i, 3, 5]-tri-alkyl-benzols is paralleled by condensation 
 of butyryl chloride to tri-ethyl-phloroglucin, with a triple rejection of 
 HC1 ; also by the condensation of two molecules j8-formyl-propionic 
 acid to terephthalic acid, with rejection of water and hydrogen. 
 
 (7) These condensations are related to the condensations of nitro- 
 malonic-acid aldehyde, and the oxy-methylene compounds (12 to 16). 
 Also to 
 
 (8) The condensation of the a-diketones to quinones ; 
 
 (9) Of acetone-oxalic acid to oxy-toluylic acid ; and 
 
 (10) The condensation of chloroform and sodium-acetic ester to 
 oxy-uvitinic-acid ester, in which methenyl-bis-acetic ester can be 
 assumed as an intermediate product. 
 
 (n) The formation of homologous salicylic acids from alkengli- 
 dene-malonic esters with Na alcoholate is based upon an intramolecular 
 aceto-acetic ester condensation. 
 
 There is also a peculiar condensation of pyro-traubenic acid to 
 methyl-dihydro-trimesinic or uvitinic acid, in which oxalic acid is first 
 split off. 
 
 These benzene formations are associated with several reactions 
 leading to hydro-aromatic compounds having a close relation to 
 benzene derivatives. We may mention the following : 
 
 i. Sodium-malonic ester condenses to phloroglucin-dicarboxylic 
 ester, formed from acetone-dicarboxylic ester and malonic ester 
 (B. 29, R. 1117). Sodium-acetonic-dicarboxylic ester condenses to 
 dioxy-phenyl-dicarboxylic ester (B. 31, 2014 ; C. 1897, II. 741). 
 All these condensation products are probably derivatives of hexa- 
 hydro-benzol. 
 
 Cp. also the condensations of sodium-acetone-dicarboxylic ester 
 with iodine to hydroquinone-tetracarboxylic ester (B. 30, 2569), with 
 eth-oxy-methylene, aceto-acetic, and eth-oxy-methylene-malonic ester 
 to oxy-trimesinic ester, and resorcin-tricarboxylic ester, respectively 
 (C. 1899, II. 1018, 1020). 
 
BENZENE RING SPLITTINGS 45 
 
 2. Succinic acid ester condenses with sodium to succinylo-succinic 
 acid ester. 
 
 3. i, 5-diketo-compounds, which contain, in the terminal place, 
 besides a CO group, a CH 3 or CH 2 R group, condense to cyclic aldols, 
 of the hexamethylene series, which easily pass into keto-tetra-hydro- 
 benzene derivatives. Methylene-bis-aceto-acetic ester, a, y-diacetyl- 
 glutaric ester, thus gives methyl-keto-tetramethylene-dicarboxylic 
 ester. Similarly, with sodium ethylate, the y-acetyl-butyric ester 
 CH 3 CO.CH 2 .CH 2 .CH 2 .COOC 2 H 5 yields dihydro-resorcin, which can, 
 by a reversed process, pass into y-acetyl-butyric acid by splitting 
 (cp. benzol ring splitting). 
 
 Some other methods of synthesising hydro-aromatic compounds 
 were mentioned on pp. 4 and 5. 
 
 BENZENE RING SPLITTINGS. 
 
 As already mentioned, the benzene derivatives are in general 
 distinguished by the tenacity of the benzene ring. In order to split 
 the benzene ring, suitable benzene derivatives are treated with reagents 
 which, partly or wholly, dissolve the double links of the nucleus. 
 The splitting is therefore always preceded by the formation of hydro- 
 aromatic intermediate products, which, as a rule, could not be retained. 
 Sometimes we obtain split products containing the six nuclear C 
 atoms in the molecule as an open chain, in some cases pentacarbocyclic 
 compounds from hexacarbocyclic a-diketones. 
 
 Ring splittings were found most easily practicable in the case of 
 phenols, amido-phenols, quinones, oxy-quinones, and phenol-carboxylic 
 acids. 
 
 i. Splitting by feeble oxidation. While strong oxidisers convert 
 the benzene nucleus into CO 2 , formic acid, and oxalic acid, ozone 
 is capable of producing a straightforward, and extremely clear, 
 splitting of benzene. By addition of three molecules of ozone to the 
 three double links of the benzene nucleus, we get, first, ozobenzol, or 
 benzol-triozonide C 6 H 6 O 9 , which is decomposed by water into three 
 molecules of glyoxal (Harries) : 
 
 0-0 
 CH O OCH 
 
 H CH OCH CHO 
 
 CHO 
 
 H AH + 3H - oin + 
 
 H O OCH 
 
 J 
 
 Vc 
 
 This splitting furnishes one of the strongest supports for Kekule's 
 benzene formula. The homologous benzene hydrocarbons behave 
 similarly. 
 
 Pyro-catechin or [i, 2]-dioxy-benzol C 6 H 4 [i,2](OH) 2 and proro- 
 catechuic acid or [3, 4>dioxy-benzoic acid CO 2 Ii[i]C 6 H 3 [3,4J(OH) 2 
 are oxidised to dioxy-tartaric acid (Kekule). 
 
46 ORGANIC CHEMISTRY 
 
 Hydroquinone or [i, 4]-dioxy-benzol, and the quinone easily 
 generated from this, are split up by silver peroxide into malemic 
 acid and CO 2 (R. Kempf) : 
 
 COH CO COOH 
 
 HC CH HC CH HC 
 
 II | > II II > II +2C0 2 
 
 HC HC HC CH HC 
 
 \/ V \ 
 
 COH CO COOH 
 
 Phenol C 6 H 5 OH has been transformed by potassium permanganate 
 solution into meso-tartaric acid (Dobner). Probably in this case also 
 quinone is formed in the first instance, and then maleinic acid, which 
 with MnO^K passes into meso-tartaric acid (see Vol. I.). 
 
 By oxidation of o-nitro-p-cresol with fuming sulphuric acid we 
 obtain jS-acetyl-acrylic acid (Schultz and Low) : 
 
 C CH 3 COCH 3 
 
 HC CH HC 
 
 II I > II 
 
 HC CN0 2 HC 
 
 C OH COOH 
 
 2. Splitting by simultaneous chlorination and oxidation. Benzene 
 treated with potassium chlorate and sulphuric acid passes first into 
 chlorinated quinone and then into trichloro-pheno-malic acid and 
 j8-trichlor-acetyl-acrylic acid (see Vol. I.), which with baryta water 
 decomposes into chloroform and maleiic acid (Kekule and Strecker) : 
 
 CH CO C0 2 H C0 2 H 
 
 HC CH HC CH HC HC 
 
 II I > \\ II -> II -> II +HCC1 3 
 
 HC CH HC CC1 HC CC1 3 HC 
 
 CH CO CO C0 2 H 
 
 Benzene Monochloro- Trichloro-pheno-malic acid Maleic acid, 
 quinone -Trichlor-acetyl-acrylic 
 acid 
 
 From phenol, salicylic acid, or ortho-oxy-benzoic acid COOH[i]C 6 H 6 
 [2]OH, and from gallic acid COOH[i]C 6 H 2 [2, 3, 4](OH) 3 , we obtain, 
 by treatment with potassium chromate and HC1, iso-trichloro-glycerinic 
 acid CC1 3 C(OH) 2 COOH (see Vol. I.). 
 
 Picric acid or [i, OH, 2, 4, 6]-trinitro-phenol, treated with bleaching 
 powder, yields chloro-picrin (Vol. I.) ; with bromine, and lime water, 
 bromo-picrin. 
 
 Specially illuminating are the methods of benzene splitting worked 
 out by Zincke. They consist in the formation of chlorinated R- 
 hexene and R-hexylene-ketones, from suitable aromatic compounds, 
 and the splitting of the former. 
 
 We shall give, in what follows, four examples, the first three of 
 which start from the three dioxy-benzols, and the fourth from [i, 3, 5]- 
 trioxy-benzol, or phloroglucin. 
 
BENZENE RING SPLITTINGS 47 
 
 (i) Pyro-catechin or o-dioxy-benzol, treated with chlorine, passes 
 into tetrachlor-ortho-quinone, and then into hexachlor-o-diketo-R- 
 hexene. By merely heating in water the latter is converted into 
 hexachloro-R-pentene-oxy-carboxylic acid, which may be oxidised by 
 means of chromic acid to hexachloro-keto-R-pentene. With caustic 
 soda the hexachloro-R-pentene-ketone splits to form perchloro-vinyl- 
 acrylic acid, which, on reduction, yields ethylidene-propionic acid 
 (B. 27, 3364) : 
 
 CCI 
 
 CCI 
 
 CCI 
 
 CCI 
 
 CCI 
 
 CH 2 
 
 CCI CO 
 
 CCI CO 
 
 ^ \ 
 CCI \ /rnw 
 
 t cci \ 
 
 CCI CO 2 H 
 
 CH C0 2 H 
 
 CCI CO 
 
 H 1 H 
 
 CC1 2 CO 
 
 H C /C0 2 K 
 CC1 2 / \OH 
 
 CC1 2 / 
 
 -H 
 CCI 
 
 ~t H 
 
 CCI 
 
 cci 2 
 
 CC1 2 
 
 CC1 2 
 
 CCI, 
 
 CH 3 
 
 Tetra- 
 
 Hexachlor- 
 
 Hexachloro-R- 
 
 Hexachloro- 
 
 Perchloro- 
 
 Ethylidene- 
 
 chloro- 
 
 o-diketo- 
 
 pentene-oxy- 
 
 keto- 
 
 vinyl- 
 
 propionic 
 
 quinone 
 
 R-hexene 
 
 carboxylic acid 
 
 R-pentene 
 
 acrylic acid 
 
 acid. 
 
 (2) The splitting up of hydroquinone is simpler. By the action of 
 chlorine upon hydroquinone, or quinone, as well as of potassium chlorate 
 and HC1 upon phenol, we can easily obtain tetrachloro-para-quinone 
 (chloranile), and from this, by chlorination, hexachloro-para-diketo- 
 R-hexene, which, with alcoholic potash, is broken up to perchlor-acroyl- 
 acrylic acid. The latter, as well as hexachloro-para-diketo-R-hexene 
 itself, are decomposed by aqueous soda into dichloro-maleic acid and 
 trichlor-ethylene (A. 267, i) : 
 
 CO 2 H CO,H 
 
 CCI CC1 2 CCI CC1 2 
 
 CCI CCI CCI CHCI 
 
 \ / \ 
 
 CO CO a H 
 
 Tetrachloro- Hexachloro- Perchlor-acroyl- Dichloro- Trichlor- 
 p-quinone p-diketo- acrylic acid maleic acid ethyl ene. 
 
 R-hexene 
 
 (3) From resorcin, with chlorine and glacial acetic acid, we obtain 
 pentachloro-resorcin, and, from the latter, heptachloro-resorcin. 
 Both m-diketo-chlorides split up in cold water alone. The penta- 
 chloro-compound becomes dichloro-acetyl-trichloro-crotonic acid, and 
 the heptachloro-compound becomes, with chlorine and water, trichloro- 
 acetyl-pentachloro-butyric acid. The dichloro-acetyl-trichloro-crotonic 
 acid, boiled in water, yields dichloro-methyl-chloro-vinyl-o-diketone. 
 The trichloro-acetyl-pentachloro-butyric acid, treated with alkalies, 
 splits into chloroform and pentachloro-glutaric acid, as does trichloro- 
 acetyl-acrylic acid. But on treating it with boiling water it passes 
 into tetrachloro-diketo-R-pentene, which, with chlorine, is trans- 
 formed into perchloro-acetyl-acrylic chloride. The chloride, with water, 
 yields the acid itself, which again, on treatment with alkalies, decom- 
 poses into chloroform and dichloro-maleic acid : 
 
4 8 
 
 C(OH) 
 CH CH 
 
 CH C(OH) CH 
 
 V 
 
 Resorcin 
 
 CO 
 
 CCI CC1 2 
 CO 
 
 ORGANIC CHEMISTRY 
 
 CO 2 H 
 CCI CC1 2 H CC1H CC1 2 H 
 
 II i -HI 1 
 
 CH CO CH CO 
 
 + C0 2 
 
 1 2 
 
 CC1 2 CCI 
 
 Pentachloro- Dichloro- 
 resorcin acetyl- 
 
 trichloro- 
 
 | crotonic acid 
 
 CO CO 2 H 
 
 CC1 2 CC1 2 CC1 2 CC1 3 
 
 I ->| I H 
 
 3HC1 CO 
 
 w 
 
 \S 
 
 Dichloro-methyl- 
 chloro-vinyl- 
 o-diketone. 
 
 C0 2 H 
 / 
 CC1 2 
 
 HC1 C0 2 H 
 
 + CHC1 3 
 
 
 HC1 CO 
 \ / 
 CCl a 
 
 Hepta- Trichloro-acetyl- Pentachloro- Chloro- 
 chloro- pentachloro- glutaric acid form, 
 butyric acid 
 
 CCl a 
 
 resorcn 
 
 CO CC1 2 
 
 CC1 
 
 CO 
 
 CC1 3 C0 2 H 
 
 CO ->CC1 CO 2 H + HCCL 
 
 COC1 CC1 3 C0 2 H 
 
 dci co ->cc\ 
 
 \ / \ / \ / \. , 
 
 CCI CCI CCI CCI 
 
 Tetrachloro- Perchloro- Perchloro- Dichloro- 
 
 diketo- acetyl-acrylic acetyl-acrylic maleiic 
 R-pentene 
 
 chloride 
 
 acid 
 
 Chloro- 
 form. 
 
 (4) The behaviour of resorcin closely resembles that of phloroglucin 
 or [i, 3, 5]-trioxy-benzol, as this passes with chlorine into hexachloro- 
 [i, 3, 5]-triketo-R-hexene. The triketone, treated with chlorine and 
 water, decomposes into octochloro-acetone, and, treated with methyl 
 alcohol, into dichloro-maionic-dimethyl ester and sym. tetrachloro- 
 acetone ; and, treated with ammonia, into three molecules dichloro- 
 acetamide (B. 23, 1706) : 
 
 C(OH) 
 
 C0 2 CH 3 
 CCl a 
 
 C0 2 CH 3 
 Dichloro- 
 
 CH 
 
 C(OH) C(OH) 
 
 CH 
 
 L 
 
 CC1 2 H 
 + CO 
 
 CC1 2 H 
 
 sym. Tetra- Phloro- 
 malonic chloro-acetone glucin 
 ester 
 
 C0 2 
 
 CC1 3 CC1 3 
 CO 
 
 1 
 CO 
 
 CO 
 
 CCl a CC1 2 
 ^CO CO 
 
 \ / \ / 
 
 CC1 2 CC1 2 
 
 Hexachloro- Octochloro- 
 [ x 3 5]-triketo- acetyl-acetone. acetamide. 
 R-hexylene 
 
 CONH 2 
 
 3 CHC1 2 
 Dichloro- 
 
 2CH 3 OH 
 
 3NH 3 
 
 In the four examples the splitting takes place between a CO group 
 and a CC1 2 group of keto-chlorides. These reactions were first 
 developed by Zincke in the naphthalin series, and used for splitting 
 up one of the naphthalin nuclei and for the transformation of naphthalin 
 derivatives into indene derivatives. Later he extended the process to 
 the above-mentioned phenols and other aromatic compounds. In a 
 similar manner Hantzsch carried out the splitting up of phenol with 
 
BENZENE RING SPLITTINGS 49 
 
 chlorine in alkaline solution, and its transformation into cyclopentene 
 derivatives (B. 22, 1238). 
 
 3. Splitting up by reduction in alkaline solution. This splitting 
 occurs in 
 
 (1) The o-phenol-car boxy lie acids during reduction with Na in amyl 
 alcohol. As intermediate products of the reduction we may assume 
 tetrahydro-acids and their transposition products hydro-aromatic-o- 
 ketone-carboxylic acids. The latter take up water and change into 
 pimelinic acids ; salicylic acid yields almost quantitatively n-pimelinic 
 acid ; while o-, m-, and p-cresotinic acids yield the three isomeric 
 methyl-pimelinic acids (Einhorn and Willstatter, B. 28, R. 744) : 
 
 COOH COOH COOH COOH 
 
 C C CH CH 2 
 
 / \ / \ /\ / 
 
 CH C.OH CH 2 COH CH 2 CO CH 2 COOH 
 
 CH CH ~* CH 2 CH 2 ~* CH 2 CH 2 CH 2 CH 2 
 
 \ S \ / \/ \/ 
 
 CH CH 2 CH 2 CH 2 
 
 This reaction has been transferred with equal success to the naph- 
 thalin-o-oxycarboxylic acids (see Naphthalin-ring splittings). 
 
 (2) Resorcin gives, on reduction, dihydro-resorcin, which, during 
 oxidation with potassium permanganate, yields n-glutaric acid (Merling, 
 A. 278, 32) ; heating for several hours with concentrated baryta solution 
 to I5o-i6o splits up dihydro-resorcin to y-acetyl-butyric acid with 
 addition of H 2 O (Vorlander, B. 28, 2348) : 
 
 C(OH) CO CO 
 
 CH CH CH 2 CH 2 CH 2 CH 3 
 
 CH C(OH) CH 2 CO CH 2 COOH 
 
 \ S \ / \ / 
 
 CH CH 2 CH 2 
 
 This reaction is reversible. 
 
 1. The Single-Nucleus Benzene 
 
 BENZENE, phene, benzol, C 6 H 6 , m.p.-h5'4, b -P- 8o '4 is tne funda- 
 mental hydrocarbon of the aromatic substances. It is generated in 
 the dry distillation of coal, and is therefore found in coal-tar, accom- 
 panied by a body most closely resembling it in physical properties, 
 viz. thiophene (q.v.) C 4 H 4 S, and numerous other compounds. Pure 
 benzene is formed by heating benzoic acid or benzol-polycarboxylic 
 acids with lime. Synthetically, benzene may be produced from acety- 
 lene by heating to high temperatures (Berthelot, 1870). 
 
 Benzene is produced from coal-tar by fractionation, and is separated 
 
 from thiophene (q.v.) by repeated shaking up with a little concentrated 
 
 sulphuric acid, treatment with aluminium chloride, or heating with 
 
 chlorine sulphide, formaldehyde, or phthalic anhydride (B. 29, R. 1000, 
 
 VOL. II. E 
 
50 ORGANIC CHEMISTRY 
 
 1152 ; C. 1902, II. 737 ; 1909, II. 666). Finally it is purified by 
 squeezing off, after being crystallised in a freezing mixture. 
 
 Historical (B. 23, 1271). Benzene was discovered by Faraday in 
 1825, in compressed illuminating gas prepared from oil. It was 
 obtained in 1834 by Mitscherlich by distillation of benzoic acid 
 with quicklime, and was discovered by A. W. Hofmann in 1845 
 in coal-tar. 
 
 Properties. Benzene is a mobile liquid of an odour resembling 
 ether, D 0-899, D 20 0-8799. It burns with a luminous flame, mixes 
 with absolute alcohol and ether, and dissolves resins and fats very easily, 
 also many hydrocarbons capable of crystallisation with crystal benzene 
 (see Triphenyl-methane). Sulphur, iodine, and phosphorus are also 
 soluble in benzene. 
 
 Behaviour and Transformations. (i) On conducting benzene 
 through an incandescent tube it is partly changed into diphenyl 
 C 6 H 5 .C 6 H 5 , and into diphenyl benzols C 6 H 4 (C 6 H 5 ) 2 , and decomposes 
 partly into acetylene. (2) On oxidising benzene with Mn peroxide 
 and H 2 S0 4 some benzoic acid is formed, obviously due to some diphenyl 
 formed intermediately (A. 221, 234), also some o-phthalic acid ; but 
 benzene is very stable against oxidisers. By silver peroxide in the 
 presence of HN0 3 , or by manganic sulphate, it is oxidised to quinone 
 (q.v.) (B. 38, 3963 ; C. 1908, I. 74). Benzene is split up by treatment 
 with C1O 3 K and H 2 SO 4 , passing into trichloro-pheno-malic acid and 
 /?-trichlor-acetyl-acrylic acid. On passing ozone through benzene 
 for some time, a white amorphous mass is obtained, the so-called 
 ozobenzol, a very explosive substance, of the formula C 6 H 6 O 9 , decom- 
 posed slowly by water with formation of glyoxal (B. 37, 3431). (3) By 
 heating with HI to 26o-28o benzene is mostly isomerised into 
 methyl-pentamethylene ; but benzene and hydrogen combine to 
 hexahydro-benzol, on passing over finely divided nickel at i8o-200 
 (C. 1901, I. 817). (4) Chlorine and bromine act upon benzene both 
 by addition and by substitution. (5) HNO 3 transforms it into 
 nitro-benzol C 6 H 5 NO 2 ; and (6) H 2 SO 4 into benzol-sulpho-acid 
 C 6 H 5 SO 3 H. The last two compounds are prepared industrially on 
 a large scale. With the help of A1 2 C1 6 and halogen alkyls, alkyl 
 residues may be introduced into benzene. (7) With aldehydes, 
 benzene is condensed by H 2 SO 4 to higher aromatic hydrocarbons 
 (see Diphenyl-methane and ethane). 
 
 COAL-TAR. 
 
 Dry distillation of coal also gives rise to many alkyl-benzols, 
 and some higher condensed aromatic bodies like naphthalin C 10 H 8 , 
 acenaphthene C 12 H 10 , fluorene C 13 H 10 , anthracene and phenanthrene 
 C 14 H 10 , fluoranthene C 15 H 10 , pyrene C 1G H 10 , and chrysene C 18 H 12 . 
 They are contained in the "coal-tar" obtained in great quantities 
 in gas-works and coke-ovens. Besides illuminating gas and tar, 
 ammonia water is formed, while coke remains in the retorts, forming 
 a fuel richer in carbon than coal itself. 
 
 For the rapid and brilliant development of aromatic chemistry it 
 has been of the greatest utility that the fundamental aromatic sub- 
 stances have been made available to chemical investigation, in any 
 
COAL-TAR 51 
 
 desired quantity, by the industry concerned. For, while the paraffins 
 were unsuitable bases for the building up of aliphatic substances, the 
 aromatic hydrocarbons, with their faculty for the most varied reactions, 
 form not only the systematic but also the practical foundation for 
 the chemistry of aromatic substances. Coal-tar, which contains these 
 hydrocarbons, is the inexhaustible source for preparing numberless 
 aromatic compounds, many of which have been most widely used as 
 dyes, perfumes, and medicines. 
 
 Working of Coal-Tar for Aromatic Hydrocarbons. Coal-tar, which, 
 besides the aromatic hydrocarbons, contains aliphatic bodies, thiophene 
 and its methylated derivatives, phenols, pyridin bases, and other 
 compounds, is first distilled into three or four fractions : 
 
 1. Light oil (3 to 5 per cent.), lighter than water, boils at 150. 
 
 2. Middle oil (8 to 10 per cent.), about the density of water, boils at 
 
 I50-2IO. 
 
 3. Heavy oil (8 to 10 per cent.), heavier than water, boils at 
 
 2IO-270. 
 
 4. Green oil, or anthracene oil (16 to 20 per cent.), of a green colour, 
 boils at 270-400. 
 
 5. Residue. Pitch (about 60 per cent.). 
 
 For the benzene compounds only light oil is in question, which is 
 freed from resins, olefins, pyridin bases, etc., by washing with sulphuric 
 acid, and then from phenols by washing with caustic soda. It is then 
 subjected to a careful fractional distillation. 
 
 Besides benzene, the following benzene hydrocarbons occur in coal- 
 tar : Toluol or methyl-benzol, the three isomeric xylols or dimethyl- 
 benzols ; ethyl-benzol, vinyl-benzol or styrol ; the three isomeric tri- 
 methyl-benzols ; mesitylene, pseudo-cumol, hemi-mellithol, n-propyl- 
 benzol, the three isomeric toluols, and durol or tetramethyl-benzol. 
 Aromatic hydrocarbons are also found freely in lignite tar, to some 
 extent in wood-tar oil, in slate-tar oil, and in rock-paraffin oil. 
 
 The bulk of the benzene and toluol of to-day is obtained from the 
 coke-oven gases, which contain about 42 grammes per cubic metre, 
 by treating the gases with coal-tar fractionings, of higher boiling- 
 points, in spraying towers. 
 
 The winning of aromatic bodies by dry distillation should be con- 
 sidered in connection with their formation by pyrogenic synthesis or 
 pyro-condensation, by conducting aliphatic bodies through incandescent 
 tubes. In dry distillation the retort walls take the place of the tubes 
 (cp. B. 29, 2691 ; 10, 853 ; 20, 660). 
 
 ALKYL-BENZOLS C n H 2nH }. 
 
 The first place among the formation processes of alkyl-benzols 
 must be given to the reactions of nuclear synthesis (Vol. I.). 
 
 i. It has been repeatedly mentioned that various symmetrical 
 trialkyl-benzols are formed by polymerisation of alkyl-acetylenes in 
 the presence of sulphuric acid, just as benzene is produced by the 
 polymerisation of acetvlene. 
 
 cr TJ 
 
 Allylene 3CH 3 .C = CH ~-^ C 6 H 3 [i,3,5](CH 3 ) 3 , mesitylene. For 
 the alkyl-acetylenes we may substitute ketones, acetone, ethyl-methyl- 
 ketone, and treat them with sulphuric acid. 
 
52 ORGANIC CHEMISTRY 
 
 2. Much more general is the reaction discovered in 1864 by Fit tig : 
 action of Na upon a mixture of brominated benzene hydrocarbons in 
 ether solution, with alkyl-bromides, and iodides (A. 129, 369 ; 131, 303 ; 
 B. 21, 3185) : 
 
 C 6 H 5 Br +CH 3 I +2Na=C 6 H 5 CH 3 +NaI +NaBr 
 C 6 H 4 Br.C 2 H 6 +C 2 H 6 I + 2 Na=C 6 H/^ 2 *? 5 +NaI +NaBr. 
 
 This reaction is a very valuable generalisation of Wiirtz's synthesis 
 of the paraffins, by the action of sodium upon halogen alkyls (Vol. I.). 
 A few drops of acetic ester promote the reaction, which is the 
 smoother, the higher the molecular weight of the alkyl iodide. 
 
 3. The synthesis of tetramethyl-methane from acetone chloride, 
 and zinc methyl (Vol. I.), corresponds to the synthesis of iso-propyl- 
 benzol out of benzol chloride and zinc methyl (B. 13, 45), and of one 
 amyl-benzol out of benzol chloride and zinc ethyl : 
 
 C 6 H 5 CHCl 2 +Zn(C 2 H 5 ) 2 =C 6 H 5 CH(C 2 H 5 ) 2 +ZnCl 2 . 
 
 4. Essentially limited to aromatic compounds, but in these 
 of very general utility, is the so-called aluminium chloride synthesis 
 discovered by Friedel and Crafts in 1877, and consisting in the action 
 of alkyl-haloids upon benzene hydrocarbons in the presence of Al 
 chloride. 
 
 In some cases the olefins react in the presence of HC1 in a manner 
 similar to the alkyl-haloids (C. 1907, II. 366). 
 
 Similar action is shown by zinc chloride, and especially iron 
 chloride (cp. Nencki, B. 32, 2414). The Al chloride can sometimes be 
 replaced by a mixture of sublimate and Al filings (see B. 35, 868). 
 Here it is probable that the alkyl-haloids first form organic compounds, 
 which then act upon the hydrocarbons (C. 1900, I. 756 ; B. 33, 815). 
 In some cases intermediate products have been preserved. The 
 reaction between benzene, ethyl chloride, and Al chloride seems to 
 traverse the following phases : 
 
 2C 6 H 6 + 3 C 2 H 6 C1 + A1 2 C1 6 = A1 2 C1 6 .C 6 H 3 (C 2 H 6 ) 3 .C 6 H 6 +3HC1 
 A1 2 C1 6 .C 6 H 3 (C 2 H 5 ) 3 .C 6 H 6 + 3 C 2 H 5 C1= A1 2 C1 6 [C 6 H 3 (C 2 H 5 ) 3 ] 2 HC1 +2HC1. 
 
 This reaction product on heating decomposes into triethyl-benzol, 
 HC1, and the compound A1 2 C1 6 .C 6 H 3 (C 2 H 5 ) 3 , which under the action of 
 HC1 can convert a fresh molecule of benzene into triethyl-benzol, so 
 that one may alkylise a large quantity of benzene with very little Al 
 chloride. Water decomposes the compound A1 2 C1 6 .C 6 H 3 (C 2 H 5 ) 3 in 
 A1(OH) 2 , HC1, and triethyl-benzol (/. pr. Ch. 2, 72, 57). There is no 
 difficulty about replacing all the H atoms of benzene by methyl and 
 ethyl groups (B. 14, 2624 ; 16, 1745). Sometimes CS 2 acts favourably 
 as a diluent (A. 235, 207 ; cp. B. 29, 2884) : 
 
 CH 3 Cl-fC 6 H 6 ~ HC1+C 6 H 5 CH 3 
 2CH 3 C1+C 6 H 6 -^-> 2 HC1+C 6 H 4 (CH 3 ) 2 
 6CH 3 C1+C 6 H 6 -^L-> 6HC1+C 6 (CH 3 ) 6 . 
 
ALKYL-BENZOLS 53 
 
 Similar reactions with the benzene hydrocarbons are shown by 
 very different halogen compounds, like chloroform, and the acid 
 chlorides. Ethyl ether also acts, in the presence of A1 2 C1 C , upon 
 benzene hydrocarbons with formation of poly-ethylated benzols (C. 
 1899, II. 755). 
 
 Disintegration reactions. 5. Curiously enough, Al chloride is as 
 suitable for disintegrating the alkyl-benzols as it is for synthesising 
 them. Under suitable conditions it is possible to detach, by means 
 of Al chloride, the side chains from one molecule of a hydrocarbon, 
 and introduce it into another molecule of the same hydrocarbon. In 
 this process, certain positions of the alkyl groups are preferred, both 
 in synthesis and in disintegration, as shown by the following scheme 
 of reactions (Anschiitz and Immendorf, B. 18, 657) : 
 
 ^ C,H 4 [i, 4l(CH s ) 2 ^ ^ C.H a [i, 3, 4, 6](CH,) 4 >_ 
 
 C 6 H S CH, ^ ^ C.H,[i, 3, 4](CH t ), ^ ^ 
 
 X C.H 4 [i, 3 ](CH,) 2 C.H,[i. 3, 4, 5](CH,) 4 ^ 
 
 ) 
 C.H. ^ C.H,[i, 3, 5](CH,), * C.(CH,).. 
 
 In the case of butyl- and amyl-benzols an isomerisation of the alkyl 
 radicles is easily effected by Al chloride (C. 1899, I. 776). 
 
 If bromine is made to act upon poly-alkalised benzols, in the presence 
 of Al bromide, the longest side chain is split off, with bromination of 
 the resultant products (C. 1899, I. 32). 
 
 6. Concentrated sulphuric acid acts similarly, both for synthesis and 
 for disintegration. 
 
 7. Dry distillation of a mixture of aromatic acids, with lime or 
 soda-lime, iron filings being added to promote heat- conduction. In 
 this case all carboxyls are split off and the fundamental hydrocarbons 
 are formed : 
 
 Benzoicacid . C 6 H 5 CO 2 H > CO 2 +C 6 H 6 Benzol 
 Toluylic acid CH 3 C 6 H 4 CO 2 H > CO 2 +C 6 H 5 CH 3 Toluol 
 Phthalic acid . C 6 H 4 (CO 2 H) 2 -- - 2CO 2 +C 6 H 6 Benzol. 
 
 8. 9, and 10. Replacement of inorganic residues in substitution products 
 by hydrogen : 
 
 8. Treatment of diazo-compounds with alcohol and alkaline stannous 
 oxide solution (B. 22, 587). This reaction is particularly important 
 for solving questions of constitution. The diazo-compounds are 
 obtained from amido-compounds, and the latter from nitro-compounds, 
 produced by the action of HNO 3 upon hydrocarbons. 
 
 9. Treatment of sulpho-acids with superheated steam, and sulphuric 
 acid, concentrated HC1, or phosphoric acid, at 180. 
 
 10. Heating of oxygen-containing derivatives, phenols, and ketones, 
 with zinc dust (Baeyer, A. 140, 295) or HI and phosphorus. It is 
 notable that in this reaction benzo-phenone C 6 H 5 .CO.C 6 H 5 is easily 
 reduced, but diphenyl-ether C 6 H 5 .O.C 6 H 5 not at all. A special facility 
 is shown in the reduction of the ketones, on passing vapours, with 
 hydrogen, over finely divided nickel at I9o-i95 (C. 1905, I. 29). 
 
 11. Many alkyl-benzols, like propyl- and isopropyl-benzols, are best 
 produced by reduction of the corresponding olenn-benzols, like 
 
54 ORGANIC CHEMISTRY 
 
 C 6 H 5 CH : CHCH 3 and C 6 H 5 C(CH 3 ) : CH 2 with Na and alcohol (B. 36, 
 621, 1628, 1632 ; 37, 1721). 
 
 Properties. The benzene hydrocarbons are mostly volatile liquids, 
 though some polymethyl-benzols (durol, penta- and hexamethyl- 
 benzol, also hexa-ethyl-benzol) are solid at ordinary temperatures. 
 They possess a peculiar, and not unpleasant, odour, and are insoluble 
 in water, though soluble in alcohol and ether. They are themselves 
 good solvents for many organic compounds, which may be precipitated 
 from them by means of petrol ether. 
 
 Behaviour and Transformations. i. With reducing agents, especi- 
 ally when the vapours are conducted with^ hydrogen over finely divided 
 nickel, the alkyl-benzols and benzene itself pass into hydro-cyclic 
 hydrocarbons. HI produces a transposition of the six-membered into 
 an isomeric five-membered hydrocarbon. 
 
 2. Of great importance is the behaviour of alkyl-benzols in oxida- 
 tion. Dilute nitric acid, chromic acid mixture, potassium perman- 
 ganate, or ferricyanide convert the side chains of the benzene homo- 
 logues into COOH groups. The number of COOH groups produced, 
 and their mutual positions, give information concerning the number 
 and position of the alcohol radicles in the oxidised benzene carbo- 
 hydrates. By careful oxidation, especially with MnO 4 K, intermediate 
 products may be obtained, when the side chains are long, the oxidation 
 taking place according to the same rules as in the fatty bodies (cp. 
 aromatic carboxylic acids). 
 
 3. Chlorine and bromine, when cold, replace H atoms of the benzene 
 nucleus, and on heating they replace the H atoms of the side chain 
 (see Toluol). 
 
 4. Concentrated nitric acid yields nitro-compounds. 
 
 5. Concentrated sulphuric acid decomposes alkyl-benzols to sulpho- 
 acids on heating, and, from these, the hydrocarbons can be formed 
 again (by method 9). A process for separating out, and purifying, the 
 benzols has been based upon this. 
 
 6. Under the action of ozone the alkyl-benzols, and benzene itself, 
 yield explosive triozonides, which are decomposed by water, with forma- 
 tion of aliphatic aldehydes (A. 343, 369). 
 
 7. With chromyl chloride CrO 2 Cl 2 the homologous benzols yield 
 compounds, from which water forms aromatic aldehydes, and ketones 
 
 8. On heating toluol or xylols with sulphur, stilbene C 6 H 5 CH : 
 CHC 6 H 5 is formed, or methylated stilbene, and further transformation 
 products (C. 1903, I. 502). 
 
 Isomerism. Of the first member of the series, toluol, the theory 
 only allows of one modification, and this is the only one found. The 
 six H atoms of benzene are equivalent. 
 
 Of xylol or dimethyl-benzol three isomers are possible, as it is a 
 di-substitution product : 
 
 o- Xyl ol C.H. m-Xylo! C.H. p-Xylo. 
 
 With these three known xylols ethyl-benzol C 6 H 5 C 2 H 5 is isomeric. 
 
 Of bodies with the formula C 9 H 12 , eight isomers are possible, and 
 these are all known : (i) three trimethyl-benzols ; (2) three ethyl- 
 
ALKYL-BENZOLS 
 
 55 
 
 methyl-benzols ; (3) two propyl-benzols : n-propyl- and isopropyl- 
 benzol. 
 
 The isomerisms are therefore determined by the position, number, 
 homology, and isomerism of the alkyls entering the benzene in replace- 
 ment of hydrogen. 
 
 Constitution. Of the syntheses of the alkyl-benzols, Fittig's reaction 
 (see above) is especially valuable, as regards conclusions respecting 
 constitution, since, as far as we know, no intramolecular atomic dis- 
 placements occur in it, the alkyls taking the places vacated by the 
 halogen atom. Oxidation also helps in deciding about the number and 
 position of the side chains. 
 
 The following table shows the most important alkyl-benzols : 
 
 Name. 
 
 Formula. 
 
 M.p. 
 
 B.p. 
 
 Density. 
 
 Toluol 
 
 C 6 H 5 CH 3 
 
 
 110-3 
 
 0-8708(13.1/4) 
 
 Xylols, Dimethyl-benzols 
 
 C 6 H 4 (CH 3 ) 2 
 
 
 
 
 o-Xylol . 
 
 
 -28 
 
 142 
 
 0-8932 (o) 
 
 m-Xylol, Isoxylol 
 
 . 
 
 -54 
 
 139 
 
 0-8812 (o) 
 
 p-Xylol . 
 
 . 
 
 + 15 
 
 138 
 
 0-8801 (o) 
 
 Ethyl-benzol 
 
 GjHjC/HqCHjj . 
 
 
 136 
 
 0-8832 (o) 
 
 Trimethyl-benzols 
 
 C 8 H 3 (CH 3 ) 3 
 
 
 
 
 [1,2,3] = Hemimellithol 
 
 
 . . 
 
 175 
 
 . . 
 
 [1,2,4]= Pseudo-cumol 
 
 . 
 
 . . 
 
 170 
 
 
 [i,3,5]=Mesitylene . 
 
 
 
 164-5 
 
 0-8694 (9-8/4) 
 
 Methyl-ethyl-benzols . 
 
 C a H 4 (CH 3 )(C 3 H ) 
 
 
 
 
 o- or [1,2]- 
 
 
 . . 
 
 159 
 
 0-8731 (16) 
 
 m- or [1,3]- 
 
 . 
 
 . . 
 
 159 
 
 0-8690 (20) 
 
 p- or [1,4]- 
 n-Propyl-benzol . 
 
 C 6 H 5 CH 2 CH 2 CH 3 '. 
 
 
 
 162 
 158-5 
 
 0-8652 (21) 
 
 0-88 10 (o) 
 
 Isopropyl-benzol, Cumol 
 Tetramethyl-benzol 
 
 C 6 H 5 CH(CH 3 ) 2 
 C 6 H 2 (CH 3 ) 4 
 
 
 153 
 
 0-8798 (o) 
 
 [i,2,3,4] = Prehnitol . 
 
 
 - 4 
 
 204 
 
 . 
 
 [i,2,3,5] = Isodurol . 
 
 . 
 
 
 196 
 
 0-8961 (0/4) 
 
 [i, 2.4,5] = Durol 
 
 . , 
 
 79 
 
 190 
 
 
 Methyl-isopropyl-benzols 
 
 C 6 H 4 (CH 3 )[CH(CH 3 ) 2 ] 
 
 
 
 
 [1,2]- . 
 
 . 
 
 . . 
 
 175 
 
 0-8723 (o) 
 
 [1.31- 
 
 . . 
 
 . . 
 
 175 
 
 0-8582 (18) 
 
 [i,4] = Cymol . 
 
 , 
 
 
 175 
 
 0-865 
 
 Pentamethyl-benzol 
 
 C 6 H(CH 3 ) 5 
 
 53 
 
 230 
 
 
 Hexamethyl-benzol 
 Penta-ethyl-benzol 
 Hexa-ethyl-benzol 
 
 C 6 (CH 3 ) 8 . 
 C 6 H(C 2 H 5 ) 5 
 C 6 (C 2 H 5 ) 4 
 
 164 
 129 
 
 264 
 277 
 298 
 
 0-8985 (19) 
 
 From this table it is seen that the position isomers of the same 
 formula, e.g. the three xylols, have closely adjoining melting-points. 
 In the dimethyl-benzols the o-compound boils at the highest tempera- 
 ture. Then come the meta- and finally the para-compound ; but the 
 p-compound has the highest melting-point. Of the tetramethyl- 
 benzols, durol is solid at ordinary temperatures, also the pentamethyl-, 
 hexamethyl-, and hexa-ethyl-benzols. 
 
 The entry of a methyl group produces in the methyl-benzols an 
 elevation of the boiling-point by about 24 to 30 : cp. toluol, xylols, 
 tri-, tetra-, penta-, and hexamethyl-benzols. Entry of CH 3 into a 
 side chain raises the boiling-point by about 24 : cp. toluol, ethyl- 
 benzol, and n-propyl-benzol. 
 
56 ORGANIC CHEMISTRY 
 
 TOLUOL C 6 H 5 CH 3 , so called because it is obtained from the dry 
 distillation of tolu balsam, is found in coal-tar in company with thio- 
 tolene or methyl-thiophene (q.v .), and is very valuable industrially. It 
 is formed according to the general methods : 
 
 (1) From bromo-benzol, methyl iodide, and sodium ; 
 
 (2) From benzene, methyl chloride, and Al chloride ; 
 
 (3) From the polymethyl-benzols and Al chloride ; 
 
 (4) From the three toluylic acids, and the methyl-poly carboxylic 
 acids, by distillation with lime, etc. 
 
 On reduction, toluol passes into hexahydro-toluol ; by oxidation with 
 dilute HNO 3 , or chromic acid, into benzoic acid ; with chromyl chloride, 
 CrO 2 Cl 2 , and water, or MnO 2 , C1 2 O 3 , and sulphuric acid, into benz- 
 aldehyde. On nitrogenation it gives o- and p-nitro-toluol ; on sulphur- 
 ising it yields much p-toluol-sulpho-acid, besides a little o-acid. 
 
 Chlorine has a remarkable action upon toluol. At boiling-point 
 only the hydrogen of the side chain is replaced, and we get : 
 
 Benzyl chloride C 6 H 5 CH 2 C1 
 Benzal chloride C 6 H 5 CHC1 2 
 Benzo-trichloride C 6 H 5 CC1 3 . 
 
 In the cold, on the other hand, o- and p-chloro-toluol are generated, 
 C 6 H 4 C1.CH 3 . In the presence of iodine and SbCl 5 chlorine only enters 
 the nucleus, even at boiling-point (Beilstein and Geitner, A. 139, 311). 
 But a little PC1 5 facilitates entry into the side chain (A. 272, 150). The 
 same effect is produced by sunlight. 
 
 Hydrocarbons C 8 H 10 . Ethyl-benzol is isomeric with the three di- 
 methyl-benzols. Of the three xylols occurring in coal-tar, iso- or m- 
 xylol is most abundant and technically important. 
 
 During oxidation with dilute HNO 3 , o- and p-xylol are oxidised to 
 o-and p-toluylic acid, and the latter to o-and p-phthalic acid respectively. 
 Metaxylol is attacked with greater difficulty. Potassium permanganate 
 also oxidises the three xylols to the corresponding toluylic acids, and 
 finally to phthalic acids. H 2 SO 4 dissolves o- and m-xylol to xylol- 
 sulpho-acids (B. 10, 1013 ; 14, 2625). On distilling raw xylol with 
 steam, p-xylol passes over first. 
 
 o-Xylol is also formed from o-bromo-toluol, CH 3 I and sodium. 
 Oxidised by MnO 4 K it passes into phthalic acid. Chromic acid burns 
 it to CO 2 and H 2 O, like many o-derivatives. 
 
 m-Xylol or iso-xylol. The production of m-xylol from mesitylenic 
 acid, by heating with lime, is theoretically important. This reaction 
 genetically connects m^xylol with mesitylene, in which the [i, 3, 5]- 
 position of the three methyl groups can be established. This proves 
 the m-position for the toluylic and phthalic acids generated by oxidation 
 of m-xylol. 
 
 H rH C H MCH^C H < H .H /[i]CO,H 
 
 6 " 3 4 " C - 
 
 Mesitylene Mesitylenic acid Isoxylol m-Toluylic acid Isophthalic acid 
 
 p-Xylol, by distillation of camphor with ZnCl 2 , also from p-bromo- 
 toluol and p-dibromo-benzol, CH 3 I and Na (B. 10, 1355). On oxidation 
 
ALKYL-BENZOLS 57 
 
 with dilute HNO 3 it gives first p-toluylic acid, then terephthalic acid, 
 and with CrO 3 terephthalic acid at once. In fuming sulphuric acid 
 it decomposes, forming a well-crystallising sulpho-acid. 
 
 Ethyl-benzol C 6 H 5 CH 2 CH 3 also occurs in coal-tar (B. 24, 1955). 
 Produced from bromo-benzol, ethyl bromide, and sodium ; or benzol, 
 ethyl bromide, and Al chloride (B. 22, 2662) ; also by reduction of styrol 
 C 6 H 5 CH = CH 2 . Dilute HNO 3 and chromic acid oxidise it to benzoic 
 acid. CrO 2 Cl 2 produces phenyl-acetaldehyde C 6 H 5 .CH 2 .CHO. 
 
 Hydrocarbons C 9 H 12 The isomerism of the eight compounds of 
 this formula has already been pointed out above. For physical 
 constants see table. 
 
 Mesitylene, symmetrical trimethyl-benzol, occurs in coal-tar, and in 
 certain naphtha fractionate (C. 1901, I. 1002), and is prepared from 
 acetone (Kane, 1837) or allylene with concentrated sulphuric acid (cp. 
 B. 29, 958, 2884). The proof of its symmetrical structure is of funda- 
 mental importance for the location of the benzene substitution products. 
 With dilute HNO 3 , mesitylene passes into mesitylenic and mesidinic 
 acids, or into uvitinic and trimesinic acids : 
 
 r[i]CH 3 f[i]C0 2 H f[i]C0 2 H r[i]C0 2 H 
 
 C 6 H 3 [ 3 ]CH 3 >C 6 HJ [ 3 ]CH 3 >C 6 Hj [ 3 ]CO 2 H >C 8 H 3 - [ 3 ]CO 2 H 
 
 l[5]CH 3 l[ 5 ]CH 3 l[ 5 ]CH 3 l[5]C0 2 H 
 
 Mesitylene Mesitylenic acid Uvitinic acid Trimesinic acid. 
 
 Under the influence of ozone, mesitylene gives a triozonide, 
 which is split by water with formation of methyl-glyoxal (A. 343, 
 
 37) 
 
 Pseudo-cumol, [1,3, 4\-trimethyl-benzol, is also contained in coal-tar. 
 
 It is separated from mesitylene by means of the less soluble sulpho- 
 acid (B. 9, 258). Also formed from bromo-p-xylol, and 4-bromo-m- 
 xylol, which determines its constitution. 
 
 Hemi-mellithol, [i, 2, ^-trimethyl-benzol, occurs in coal-tar (B. 42, 
 3603) ; prepared from isodurylic acid C 6 H 2 (CH 3 ) 3 COOH, and from 
 2-bromo-m-xylol with CH 3 I and Na. 
 
 The three ethyl-toluols have been obtained from the three bromo- 
 toluols with ethyl halides and Na. All these isomers are found in 
 coal-tar (B. 42, 3613). 
 
 p-Ethyl-toluol, m.p. 162, has been obtained from p-methyl-styrol 
 and from p-cresyl-ketone by reduction (B. 28, 2648 ; 36, 1637). 
 
 n-Propyl-benzol, from bromo-benzol, n-propyl bromide or iodide 
 and Na ; from benzyl chloride and zinc ethyl ; from benzene, n-propyl 
 bromide, and A1 2 C1 6 at 2 (B. 24, 768) ; and from propenyl-benzol 
 C 8 H 5 CH : CHCH 3 with Na and alcohol (B. 36 r 622). Also found in 
 coal-tar. 
 
 Isopropyl-benzol, cumol, C 6 H 5 CH(CH 3 ) 2 , first obtained by distillation 
 of cuminic acid (CH 3 ) 2 CHC 6 H 4 COOH with lime. Synthetically from 
 benzal chloride and Zn(CH 3 ) 2 ; and from benzene, isopropyl chloride 
 or bromide, and Al chloride. Since heat transposes n-propyl bromide, 
 with A1 2 C1 6 , into isopropyl bromide, the Al synthesis gives isopropyl- 
 benzol even when n-propyl bromide is used, unless the process is 
 conducted in the cold. Cumol is best prepared synthetically by the 
 reduction of isopropenyl-benzol C 6 H 5 C(CH 3 ) : CH 2 with Na and alcohol 
 
58 ORGANIC CHEMISTRY 
 
 (B. 35, 2640). In the animal body cumol is oxidised to propyl-phenol 
 (B. 17, 2551). 
 
 In the hydrocarbons C 10 H 14 theory predicts 22 isomers : 
 
 C.H 2 (CH 3 ) 4 C. 
 3 isomers 6 isomers 3 isomers 6 isomers 4 isomers. 
 
 (a) Tetramethyl-benzols C 6 H 2 (CH 3 ) 4 . The three possible isomers 
 are known : 
 
 Durol, [i, 2 4, 5]- or sym. tetramethyl-benzol, is found in coal-tar 
 (B. 18, 3034). Prepared from 6-bromo-pseudo-cumol and 4, 6-dibromo- 
 m-xylol with CH 3 I and Na ; from toluol and pseudo-cumol with CH 3 C1 
 and Al chloride (B. 35, 868) ; and from penta- and hexamethyl-benzol 
 with A1 2 C1 6 . On oxidation it passes into durylic acid and cumidinic 
 acid, thus proving its constitution (B. 11, 31). Concentrated H 2 SO 4 
 converts durol into hexamethyl-benzol and the sulpho-acids of prehnitol, 
 pseudo-cumol, and isoxylol, which can be separated by means of 
 their amides. Similar behaviour is shown by pentamethyl and 
 penta-ethyl-benzols. 
 
 Isodurol, [i, 2, 3, 5]- or unsym. tetramethyl-benzol, from bromo- 
 mesitylene, CH 3 I and Na (B. 27, 3441), which proves its constitution ; 
 also from camphor and Zn chloride or iodide (B. 16, 2259). By oxida- 
 tion it gives 3-isodurylic acid (B. 15, 1853), and finally, mellophanic 
 acid. 
 
 Prehnitol, [i, 2, 3, 4]- or v-tetramethyl-benzol, from 2-bromo-pseudo- 
 cumol, and from 2, 4-dibromo-m-xylol, CH 3 I and Na (B. 21, 2821). 
 Oxidised to prehnitylic acid C 6 H 2 (CH 3 ) 3 COOH (B. 19, 1214), and 
 prehnitic acid C 6 H 2 (COOH) 4 . 
 
 (6) Dimethyl-ethyl-benzols: [i, 2, 4], b.p. 189, and [i, 3, 4], b.p. 184; 
 [i, 4, 3], b.p. 185, from camphor with ZnCl 2 and iodine, and from the 
 corresponding dimethyl-vinyl-benzols by reduction (B. 23, 988, 2349 > 
 36, 1637); [1,3,5], b.p. 185, from acetone and methyl-ethyl-ketone 
 with SO 4 H 2 (B. 18, 666 ; 25, 1533). 
 
 (c) Three diethyl-benzols oxidise first to ethyl-benzoic acids and 
 then to phthalic acids. p-Diethyl-benzol, b.p. 183, has also been 
 obtained from p-ethyl-styrol by reduction (B. 36, 1633). 
 
 (d) Methyl-n-propyl-benzols. The most important is the p-com- 
 pound, cymol. m-Methyl-isopropyl-benzol is found in light resin oil 
 (A. 210, 10). Also generated on heat ing fenc hone (q.v.) with phosphorus 
 pentoxide (A. 275, 157). o-Methyl-isopropyl-benzol has been prepared 
 from o-bromo-cumol with Na, and methyl iodide (B. 34, 1950). 
 
 Cymol, [i, 4]-methyl-isopropyl-benzol (see Table, p. 55), found in 
 Roman carraway oil from the seeds of Cuminum cyminum besides 
 cuminaldehyde, in the oil from the seeds of Cicuta virosa, in thyme oil, 
 eucalyptus oil, and many other etheric oils. Prepared from thymol, 
 carvacrol, or camphor with P 2 S 5 (B. 16, 791, 2259) or P 2 O 5 (A. 172, 
 307) ; from turpentine oil, and other terpenes, with withdrawal of 
 2H, by SO 4 H 2 or iodine. We must note the formation of cymol on 
 boiling cumin alcohol with zinc dust, and from citral. Synthetically, 
 cymol is produced from p-brom-isopropyl-benzol, CH 3 I and Na, which 
 fixes its constitution (B. 24, 439, 970, 1362). Cymol has a pleasant 
 
HIGHER HOMOLOGUES OF TOLUOL 59 
 
 odour. The cymol-sulpho-salt of barium (C 10 H 13 SO 3 ) 2 Ba+3H 2 O, 
 crystallising in shiny scales, is characteristic. 
 
 By dilute HNO 3 , and chromic acid mixture, cymol is converted into 
 paratoluylic acid and terephthalic acid ; but in the animal organism it 
 is oxidised to cuminic acid, also on shaking up with NaHO and air. 
 MnO 4 K yields p-oxy-isopropyl-benzoic acid (CH 3 ) 2 C(OH)C 6 H 4 COOH. 
 The action of concentrated HNO 3 upon cymol, produces p-tolyl-methyl- 
 ketone (B. 19, 588 ; 20, R. 373). 
 
 (e) Butyl-benzols : n-Butyl-benzol, b.p. 180. Isobutyl-benzol, 
 b.p. 167. Sec.-butyl-benzol, b.p. 174, by reduction of sec.-butenyl- 
 benzol C 6 H 5 C(CH 3 ) : CHCH 3 (C. 1900, I. 591 ; B. 35, 2642). Teft- 
 butyl-benzol, b.p. 167. The latter is not attacked by bromine in 
 sunlight, in the cold (B. 23, 2412 ; 27, 1610). 
 
 HIGHER HOMOLOGUES OF TOLUOL. 
 
 We may mention the following : 
 
 HYDROCARBONS C U H 16 . Pentamethyl - benzol and hexamethyl- 
 benzol from toluol, xylol, mesitylene, CH 3 C1, and A1 2 C1 6 (B. 20, 896) . For 
 behaviour with SO 4 H 2 see Durol. [1, 3, 5]-Diethyl-methyl-benzol, b.p. 
 200, from a mixture of acetone and methyl-ethyl-ketone, with sulphuric 
 acid. [1, 2, 4, 5]-Trimethyl-ethyl-benzol, ethyl-pseudo-cumol, b.p. 207 
 (B. 25, 1530 ; 36, 1641). Ethyl-mesitylene, b.p. 208 (B. 29, 2459 ; 
 36, 1642). [l,3]-Methyl-tert.-butyl-benzol, b.p. i85-i87, occurs in 
 resin essence, the distillation product of fir resin ; prepared from 
 toluol, isobutyl bromide, and A.\ 2 C\ Q . Its trinitro-derivative forms 
 artificial musk (B. 27, 1606). The isomeric p-tert.-butyl-toluol, b.p. 
 190, is obtained from toluol and isobutyl alcohol with fuming sul- 
 phuric acid (C. 1898, I. 450). Amyl-benzols, see C. 1899, I. 776 ; B. 
 35, 2644. 
 
 HYDROCARBONS C 12 H 18 . Hexamethyl-benzol, by polymerisation 
 of crotonylene with SO 4 H 2 ; by heating xylidin chloride with methyl 
 alcohol to 300 ; also by analogy with durol. Insoluble in SO 4 H 2 , 
 as it cannot form a sulpho-acid. Potassium permanganate oxidises 
 it to benzol-hexacarboxylic acid C 6 (COOH) 6 , mellithic acid. p-Di-n- 
 propyl-benzol, b.p. 219, from p-dibromo-benzol, and p-n-Propyl- 
 isopropyi-benzol, b.p. 212, from cumyl chloride C1CH 2 .C 6 H 4 CH(CH 3 ) 2 
 with Zn(C 2 H 5 ) 2 . These bodies both yield n-propyl-benzoic acid, 
 isomeric with cuminic acid, on oxidation with HNO 3 . Propyl- 
 mesitylene, b.p. 221 (B. 29, 2459) ; Isobutyl-mesitylene, b.p. 228 ; 
 iso-amyl-mesitylene, b.p. 241 , by reduction of the corresponding 
 acyl-mesitylenes (B. 37, 1715). 
 
 [1, 3, 5]-Triethyl-benzol, b.p. 218, from ethyl-methyl-ketone with 
 sulphuric acid ; from benzene, ethyl chloride, and A1 2 C1 6 we obtain, 
 besides -the sym. form, the as- or [i, 2, 4]-triethyl-benzol, b.p. 218, 
 which can be separated from the former by the greater stability of 
 its sulpho-acid, against phosphoric acid, and can also be obtained by 
 reduction of diethyl- vinyl-benzol (/. pr. Ch. 2, 65, 394 ; B. 36, 
 1634). [1, 2, 3, 4]-f etraethyl-benzol, b.p. 251. [1, 2, 4, 5]-Tetraethyl- 
 benzol, m.p. +13, b.p. 250 (B. 36, 1635). Pentaethyl-benzol. 
 Hexaethyl-benzol from C 6 H 6 , C 2 H 5 Br or ether and A1 2 C1 6 (B. 16, 1745 ; 
 21. 2819). Optically active Hexyl-benzols C 6 H 5 CH 2 CH 2 CH(CH 3 )C 2 H 5 , 
 
60 ORGANIC CHEMISTRY 
 
 b.p. 220, and C 6 H 5 CH(CH) 3 .CH 2 .CH(CH 3 ) 2 , b.p. 197, s. B. 37, 654, 
 2308. Active p-Isopropyl-hexyl-benzol C 3 H 7 .C 6 H 4 CH 2 .CH 2 .CH(CH 3 ), 
 C 2 H 5 , b.p. 265 (B. 38, 2313). Heptyl-benzol C 6 H 5 CH(CH 3 )CH 2 
 CH 2 C(CH 3 ) 2 (B. 35, 2645). Tert.-p-butyl-ethyl-benzol, b.p. 209, 
 from p-butyl-aceto-phenone (C. 1905, I. 29). Tert.-p-dibutyl-benzol, 
 m.p. 76, b.p. 236 (C. 1904, II. 1112). 
 
 By Fittig's method the following mono- and di-alkyl-benzols with 
 long side chain were obtained from bromo-benzol and bromo-toluol : 
 n-Octyl-benzol, b.p. 262. Cetyl-benzol C 6 H 5 .C 16 H 33 , m.p. 27, b.p. 15 
 230. o-Methyl-eetyl-benzol, m.p. 8-9, b.p. 15 239. m-Methyl-cetyl- 
 benzol, m.p. io-i2, b.p. 15 237. p-Methyl-cetyl-benzol, m.p. 27, 
 b.p. 15 240. Octo-decyl-benzol, m.p. 36, b.p. 15 249 (B. 21, 3182). 
 
 2. Halogen Derivatives of the Benzene Hydrocarbons. 
 
 A. HALOGEN SUBSTITUTION PRODUCTS OF BENZENE. 
 
 As a cyclic triolefin, benzene, in sunlight, adds six atoms Cl or Br, 
 thus forming benzene hexachloride and benzene hexabromide 
 bodies which, as derivatives of cyclohexane, are treated later in con- 
 nection with hexahydro-benzol. But the H atoms attached to the 
 benzene nucleus are also easily replaced by chlorine and bromine, 
 more easily than the H atoms of the paraffins. 
 
 Properties and Behaviour. The halogen benzols are partly colour- 
 less liquids, partly colourless crystalline compounds. They have a 
 feeble, but not unpleasant, odour. They are not soluble in water, 
 but easily in other solvents, and volatilise without decomposition. 
 Of the dihalogen benzols the para-compounds are solid, at ordinary 
 temperatures. They melt at higher temperatures than the ortho- 
 and meta-compounds, but boil at lower temperatures. 
 
 There is a remarkably close attachment of the halogen atoms to 
 the benzene nucleus. They do not make a double decomposition 
 (or only with great difficulty) with alkaline hydroxides, ammonia, 
 potassium cyanide, etc. (B. 18, 335 ; 20, R. 712) ; but metals like 
 Mg, Na, and Cu extract halogens, especially from benzol bromides and 
 iodides. This is of importance for the synthesis of homologous benzene 
 hydrocarbons. There is a notable facility of reaction of chloro-, bromo-, 
 and iodo-benzol with piperidin, forming phenyl-piperidin ; prolonged 
 heating with dimethyl-amine leads to dimethyl-aniline (B. 21, 2279 ; 
 C. 1898, II. 478). Small quantities of powdered copper, or copper 
 salts, which act catalytically, greatly favour the transformation with 
 ammonia, and amines (C. 1909, 1. 475 ; B. 40,4541). Sodium amalgam 
 in alcoholic solution, HI (C. 1898, II. 422 ; /. pr. Ch. 2, 65, 564), and 
 phosphorus, as well as Ni and H at 270 (C. 1904, I. 720), reduce the 
 halogen benzols to benzene. 
 
 Fluoro-benzols are formed from benzol-diazo-piperididene by adding 
 hydrofluoric acid (Wallach, A. 243, 221) 
 
 C 6 H 6 N=N NC B H 10 +2HF1=C 6 H 6 F1+N 2 +NH.C 6 H 10 .HF1. 
 
 They are formed from the benzol-diazonium chlorides, sulphates, 
 and fluorides (q.v.) by decomposition with aqueous solutions of HF 
 (C. 1898,^1. 1224 ; 1900, I. 145 ; 1905, I. 1230). 
 
HALOGEN SUBSTITUTION PRODUCTS OF BENZENE 61 
 
 Fluoro-benzol CeH^F, m. p. 41-2, b.p. 85, D 4 ^ 1-0236, has also 
 been obtained by heating fluoro-benzoic acid with HC1. 
 
 p-Difluoro-benzol C 6 H 4 [i,4]F 2 , b.p. 88, D i-n. 
 
 Chloro-benzols. Modes of formation : (i) Free chlorine acts but 
 slowly upon benzene. Its action is assisted by I, MoCl 5 ,VCl 4 (C. 1904, 
 I. 87), FeCl 3 (C. 1899, II. 287), or A1C1 3 . Chlorination can also be 
 accomplished with PbCl 4 .2NH 4 Cl (C. 1903, I. 283, 570). 
 
 (2) The hydroxyl group of the phenols is chlorinated with difficulty 
 by PC1 5 ; in the nitro-phenols this replacement is easier. 
 
 (3) A very important process for forming chloro-benzols, and 
 aromatic halogen derivatives generally, is based upon the transforma- 
 tions of the so-called diazo-compounds, obtained from amido-com- 
 pounds, the reduction products of nitro-compounds. These reactions 
 involve no atomic displacement, the chlorine taking the place pre- 
 viously occupied by the diazo-, amido-, or nitro-group. 
 
 Benzol-diazonium-chlorideC 6 N 5 N 2 Cl=C 6 H 5 Cl+N 2 . 
 
 If, therefore, in the di- and poly-substitution products the consti- 
 tution of one of these bodies is known, the constitution of the others 
 is determined. 
 
 Name. 
 
 Formula. 
 
 M.p. 
 
 B.p. 
 
 D. 
 
 Monochloro-benzol . 
 
 CH 5 C1 
 
 -45 
 
 132 
 
 1-128 (o) 
 
 " 2]-(o)-Dichloro-benzol . 
 
 C 6 H 4 C1 2 
 
 
 1 80 
 
 
 ; 3]-(m)-Dichloro-benzol . 
 
 . . 
 
 
 172 
 
 
 '. 4]-(p)-Dichloro-benzol . 
 
 . . 
 
 +53 
 
 172 
 
 
 ! 2, 3]-(v)-Trichloro-benzol 
 ' 2, 4]-(as)-Trichloro-benzol 
 
 C 6 H 3 C1 3 
 
 16 
 63 
 
 218 
 213 
 
 
 '. 3 5]-(s)-Trichloro-benzol 
 
 
 54 
 
 208 
 
 
 '. 2 3 4]-(v)-Tetrachloro-benzol 
 
 C 6 H 2 C1 4 
 
 46 
 
 254 
 
 
 2 3> 5]-(as)-Tetrachloro-benzol 
 
 
 y>l 
 
 246 
 
 
 '. 2, 4, 5]-(s)-Tetrachloro-benzol 
 
 
 
 244 
 
 
 Pentachloro-benzol . 
 
 C 6 HC1 5 
 
 86 
 
 276 
 
 
 Hexachloro-benzol . 
 
 C 6 C1, 
 
 226 
 
 326 
 
 
 In the chlorination of chloro-benzol, p-dichloro-benzol is mostly 
 formed, with but little o-dichloro-benzol (B. 29, R. 648) ; p-dichloro- 
 benzol is also obtained from p-quinone (q.v.) with PC1 5 . Further 
 chlorination of o-, m-, and p-dichloro-benzol yields 1, 2, 4-trichloro- 
 and 1,2,4, 5-tetrachloro-benzol (C. 1905, II. 1528). Characteristic, 
 for the dichloro-benzols, is their behaviour on nitrogenation : 
 
 o-Dichloro-benzol gives [i, 2]-dichloro-4-nitro-benzol, m.p. 43 
 m-Dichloro-benzol [i, 3]-dichloro-4-nitro-benzol, 32* 
 p-Dichloro-benzol [i, 4]-dichloro-3-nitro-benzol, 55. 
 
 Hexachloro-benzol (Julin's " chlorocarbon ") has also been obtained 
 by the thorough chlorination of many alkyl-benzols, and other benzene 
 derivatives (B. 29, 875). It is also formed on conducting CHC1 2 or 
 C 2 C1 4 through an incandescent tube. 
 
 Bromo-benzols have been obtained in a manner quite similar to the 
 chloro substitution products, i.e. (i) by direct substitution, through 
 bromine carriers, like Al bromide (B. 10, 971) or a mixture of sulphur 
 bromide and HNO 3 (B. 33, 2883 ; C. 1901, II. 750) ; (2) from 
 phenolene ; (3) from diazo-compounds (q.v.). 
 
62 
 
 ORGANIC CHEMISTRY 
 
 Name. 
 
 Formula. 
 
 M.p. 
 
 B.p. 
 
 D. 
 
 VIonobromo-benzol 
 
 C 6 H 5 Br 
 
 -3i 
 
 155 
 
 1-517 (o) 
 
 "i, 2] -(o)-Dibro mo-benzol j C 6 H 4 Br 2 
 
 + 7-8* 
 
 224 
 
 "i, 3]-(m)-Dibromo-benzol 
 
 . . 
 
 - 6-5 * 
 
 219-4 * 
 
 
 :i.4Hi 
 
 .1.2,3. 
 
 3) -Dibromo-benzol 
 -(v)-Tribromo-benzol C 6 H 3 Br 3 
 
 89 
 
 87 
 
 219 
 
 
 1.2,4; 
 
 - (as) -Tribromo-benzol 
 
 44 
 
 275' 
 
 1.3.5 
 
 - (s) -Tribromo-benzol 
 
 . . 
 
 H9 
 
 278 
 
 X2, 3, 
 
 4J-(v)-Tetrabromo-benzol C 6 H 2 Br 4 
 
 
 
 1,2, 3,5]-(as)-Tetrabromo-benzol .. 98 
 
 329' 
 
 i, 2, 4, 5]-(s)-Tetrabromo-benzol j 
 Pentabromo-benzol . . C 6 HBr 5 
 
 175 
 160 
 
 (6.28,191) 
 (C. 1900, 1. 809) 
 
 Hexabromo-benzol . . . C 6 Br 6 
 
 315 
 
 
 Of the dibromo-benzols we obtain on bromination of benzene with 
 heat chiefly the p-compounds, more rarely the o-compounds (B. 10, 
 I 345)- Characteristic of the dibromo-benzols, as of the dichloro- 
 benzols, is their behaviour on nitrogenation. 
 
 The generation of tribromo-benzols from the three dibromo-benzols 
 has been used for constitution determinations of all these bodies 
 (Kdrner). Hexabromo-benzol is generated by heating CBr 4 to 300. 
 
 Chloro-bromo-benzols, see C. 1899, I. 835 ; II. 959. 
 
 lodo-benzols are obtained (i) by heating benzene, iodine, and 
 HI to 200 (Kekule). The action is represented by the equation 
 (A. 137, 161) : 
 
 5C 6 H 6 -f 4 I+I0 3 H=5C 6 H 5 I= 3 H 2 0. 
 
 (2) By treating benzene with a mixture of I 2 S 2 and HNO 3 (B. 33, 
 2875 ; C. 1901, II. 750). 
 
 (3) More usually, iodo-benzols are prepared from the corresponding 
 amido-compounds with the help of the diazo-com pounds (q.v.). 
 
 (4) Bromo-benzol may be transformed to iodo-benzol by changing 
 it in ether solution to phenyl-magnesium bromide, and then treating 
 with iodine (C. 1903, I. 318) : 
 
 C 6 H 6 Br 
 
 ~> C 6 H 5 MgBr 
 
 C 6 H 5 I+MgBrI. 
 
 Name. 
 
 Formula. 
 
 M.p. 
 
 B.p. 
 
 [odo-benzol 
 
 C 6 H 6 I 
 
 -30 
 
 188 
 
 [ , 2]-(o)-Di-iodo-benzol 
 
 C 6 H 4 I 2 
 
 +27 
 
 286 
 
 \ , 3]-(m)-Di-iodo-benzol 
 
 
 40 
 
 285 
 
 , 4J-(p)-Di-iodo-benzol 
 
 
 129 
 
 285 
 
 .2, 3]-(v)-Tri-iodo-benzol 
 ,2, 4]-(as)-Tri-iodo-benzol 
 
 C 6 H 3 I 3 
 
 116 * 
 91-4 * 
 
 
 '. 3. 5]-(s)-Tri-iodo-benzol 
 '_ , 2, 3, 4]-(v)-Tetra-iodo-benzol 
 | , 2, 4, 6]-(as)-Tetra-iodo-benzol 
 , 2, 4, 5]-(s)-Tetra-iodo-benzol 
 
 C 6 H 2 I 4 
 
 184-4 
 136* 
 148 
 254* 
 
 see 
 B. 34, 3343 ; 
 C. 1901, II. 535 
 
 Penta-iodo-benzol 
 
 C 6 HI 5 
 
 172 
 
 J 
 
 Hexa-iodo-benzol 
 
 C 6 I 8 
 
 I40-i5o 
 
 
 Hexa-iodo-benzoi C 6 I 6 forms during thorough iodination of benzol- 
 carboxylic acids (benzoic acid, terephthalic acid) with iodine and 
 
HALOGEN SUBSTITUTION PRODUCTS OF BENZENE 63 
 
 fuming sulphuric acid. It forms reddish-brown needles which melt 
 and decompose at I4O-I5O (B. 29, 1631). 
 
 1, 3, 5-Tri-iodo-2-chloro-benzol (C. 1907, 1. 632). About Bromo-iodo- 
 benzols (B. 29, 1405 ; C. 1899, II. 371). 1, 3, 5-Tri-iodo-2, 4, 6-tribromo- 
 benzols C 6 Br 3 I 3 , m.p. 322 (C. 1898, II. 972). 
 
 Iodide chlorides ; lodoso-benzol ; lodo-benzol ; Diphenyl-iodonium 
 hydroxide. The iodo-benzols and their homologues, by the action of 
 chlorine or substances easily liberating chlorine, are transformed into 
 iodide - chlorides, e.g. phenyl iodide - chloride C 6 H 6 IC1 2 (Willgerodt, 
 1886). These contain chlorine bound to iodine, and may therefore be 
 referred to iodine trichloride IC1 3 . The formation of these peculiar 
 compounds is useful for the characterisation of iodinated benzene 
 derivatives. The iodo-chlorides are easily changed into iodoso- 
 benzols, and should be regarded as the chlor-anhydrides of the latter. 
 From the iodoso-benzols we arrive through oxidation at the iodo- 
 benzols, e.g. C 6 H 5 IO 2 . From iodoso- and iodo-benzol we finally obtain 
 the strongly basic diphenyl-iodonium hydroxide. 
 
 Phenyl-iodo-ehloride C 6 H 5 IC1 2 , yellow needles, formed on conduct- 
 ing chlorine through a solution of iodo-benzol in chloroform. By 
 heating it is changed into p-iodo-chloro-benzol with liberation of 
 chlorine (C. 1907, 1. 1198 ; II. 43). Shaken up with water and alkalies 
 or other bases, it yields iodoso-benzol : 
 
 C 6 H 5 IC1 2 +2KOH=C 6 H 5 IO+2KI+H 2 O. 
 
 lodoso-benzol C 6 H 5 IO is an amorphous substance exploding about 
 210 ; treated with acidulated KI solution, it gives up its oxygen with 
 liberation of the equivalent quantity of iodine : 
 
 C 6 H 5 IO+2KI+2CH 3 COOH-C 6 H 5 I+2CH 3 COOK+2l+H 2 O. 
 
 It has a basic character, and yields salts derivable from the hypo- 
 thetical hydrate C 6 H 5 I(OH) 2 , like C 6 H 5 I(OOCCH 3 ) 2 ; we must there- 
 fore regard C 6 H 5 IC1 2 as an iodoso-benzol chloride. 
 
 Iodo-benzol C 6 H 5 IO 2 , by heating iodoso-benzol by itself, or by 
 boiling in water : 
 
 2C 6 H B IO=C 6 H fi I+C 6 H B IO 2 ; 
 
 also by oxidation of iodoso-benzol with hypochlorous acid, or treat- 
 ment of phenyl-iodo-chloride with bleaching-powder solution (B. 29, 
 1567 ; cp. B. 33, 853). It is also formed direct from iodo-benzol by 
 oxidation with K persulphate and concentrated H 2 SO 4 (Caro's reagent, 
 B. 33, 533). Iodo-benzol explodes at 227-230. It exhibits the 
 behaviour of a super-oxide. 
 
 With concentrated HF, iodo-benzol yields benzol-iodo-fluoride 
 C 6 H 5 IOF 2 , which with water regenerates iodo-benzol (B. 34, 2631). 
 
 Diphenyl-iodonium hydroxide (C 6 H 5 ) 2 IOH is only known in aqueous 
 solution. Generated by shaking up a mixture of iodoso- and^ iodo- 
 benzol with moist silver oxide, according to the equation 
 
 C 6 H 5 IO+C 6 H 5 I0 2 +AgOH^(C 6 H 5 ) 2 I.OH+I0 3 Ag. 
 
 Its iodide is formed on boiling iodo-benzol with KI solution (B. 29, 
 2008). Diphenyl-iodonium hydroxide has a strong alkaline reaction, 
 and forms salts resembling those of thallium ; the carbonate and 
 
64 ORGANIC CHEMISTRY 
 
 nitrate are very soluble. The chloride and bromide form white 
 precipitates. 
 
 Diphenyl-iodonium iodide (C 6 H 5 ) 2 I.I is polymeric with iodo-benzol. 
 It forms yellow needles soluble in alcohol with difficulty. They melt 
 at I75-I76, forming iodo-benzol (V. Meyer, B. 27, 1592 ; 28, R. 80). 
 
 Fat-aromatic iodonium salts are obtained by transformation of 
 acetylene-silver chloride with aromatic iodo-chlorides : 
 
 2C.H 6 IC1 2 +HCE=CAg,AgCl =C1HC : CCK 
 
 Dichloro-vinyl-phenyl-iodonium chloride, m.p. 174. Bromide 
 decomposes at 162. The free base is unstable (A. 369, 132). 
 
 A number of homologous and substituted iodo-chlorides, iodoso- 
 and iodo-benzols, and iodonium hydroxides have been prepared (see 
 C. 1900, I. 761 ; 1902, II. 1196 ; B. 34, 3406, 3666 ; 37, 1301 ; 39, 
 269). 
 
 B. HALOGEN DERIVATIVES OF THE ALKYL-BENZOLS. 
 
 Under the same conditions as in benzene itself, in the cold, in the 
 presence of I, MoCl 5 , VC1 4 , FeCl 3 , sulphur bromide, and HNO 3 (B. 33, 
 2885), so in the alkyl-benzols the chlorine and bromine atoms enter 
 almost solely into the benzene residue, and aromatic substitution 
 products are formed. Thus, toluol yields : 
 
 C 6 H 5 CH 3 > C 6 H 4 C1.CH 3 > C 6 H 3 C1 2 CH 3 , etc. 
 
 C 6 H 6 CH 3 > C 6 H 4 BrCH 3 > C 6 H 3 Br 2 CH 3 , etc. 
 
 But on conducting Cl and Br through the boiling alkyl-benzols, 
 hardly anything but the hydrogen of the side chain is replaced, and 
 aliphatic substitution products are obtained. Thus, from toluol 
 
 C 6 H B CH 3 > C 6 H 5 CH 2 C1 > C 6 H 5 CHC1 2 > C 6 H 5 CC1 3 
 
 Benzyl chloride Benzal chloride Benzo-trichloride 
 
 are obtained, corresponding to 
 
 CH 3 CH 2 C1 > CH 3 CHC1 2 > CH 3 CC1 3 
 
 Ethyl chloride Ethylidene chloride Methyl chloroform. 
 
 These are dealt with in connection with the corresponding oxygenated 
 compounds : 
 
 C 6 H 5 CH 2 OH > C 6 H 5 CHO > C 6 H 5 CO 2 H 
 
 Benzyl alcohol Benzaldehyde Benzoic acid 
 
 into which they can be easily converted, and from which they can be 
 obtained by means of PC1 5 . 
 
 In sunlight, Cl and Br produce substitutions of the aliphatic side 
 chains of the lower homologues, even when cold (B. 20, R. 530 ; cp. 
 B. 35, 868). Isopropyl-benzol is transformed by Cl, at boiling-point, 
 into p-chlorisopropyl-benzol (B. 26, R. 771). PC1 3 also attacks the 
 alkyles of the alkyl-benzols when hot. In this and many other 
 reactions the presence of other substituents, in the benzene nucleus, 
 exercises an impeding influence (C. 1898, I. 367, 1019). 
 
HALOGEN DERIVATIVES OF THE ALKYL-BENZOLS 65 
 
 The two other methods for preparing the halogen derivatives of 
 benzene, viz. " the action of halogen phosphorus compounds upon 
 oxy-benzols, and the transformation of the corresponding diazo-com- 
 pounds, give alkyl-benzols, with substitution of halogens in the benzene 
 residue. A substitution can take place both in the aromatic and the 
 aliphatic residue of the same alkyl-benzol. The halogen atoms entering 
 the side chain are always capable of reaction. They freely exchange 
 for radicles, whereas the halogen atoms entering the benzene residue 
 are very strongly bound. The aromatic monohalogen derivatives of 
 the alkyl-benzols, especially the bromalkyl-benzols, are often used 
 for building up higher alkyl-benzols by Fittig's method. Of some 
 importance for recognising the constitution is the oxidation of the 
 side chains to carboxyl groups, which enables us also to determine the 
 halogen atoms in the side chains. 
 
 With sodium amalgam in alcoholic solution, or with HI, the 
 halogens are replaced by hydrogen. 
 
 Of the very numerous aromatic halogen substitution products of 
 this kind we may here enumerate the simplest representatives of the 
 monohalogen toluols : 
 
 Name. 
 
 Formula. 
 
 M.p. 
 
 B.p. 
 
 [I. 2> 
 
 o-Fluoro-toluol 
 
 CH 3 [i]C 6 H 4 [2]F 
 
 
 n 4 (C. 1906, II. 1830) 
 
 [i. 3> 
 
 m-Fluoro-toluol 
 
 CH 3 [i]C B H 4 f3lF 
 
 
 H5 
 
 [i, 41- 
 
 p-Fluoro-toluol 
 
 CH 3 [i : 
 
 C 6 H 4 [ 4 ]F 
 
 
 116 
 
 [i, 2]- 
 
 o-Chloro-toluol 
 
 CH 3 [i; 
 
 C 6 H 4 [2]C1 
 
 -34 
 
 156 
 
 [i, 31- 
 
 m-Chloro-toluol 
 
 CH 3 [i 
 
 C 6 H 4 [ 3 ]C1 
 
 -48 
 
 150 
 
 [i. 4l- 
 
 p-Chloro-toluol 
 
 CH 3 [i] 
 
 C 6 H 4 [ 4 ]C1 
 
 _!_ f 
 
 1 
 
 163 
 
 [I, 2]- 
 
 o-Bromo-toluol 
 
 CH.CI 
 
 C 6 H 4 [2]Br 
 
 -26 
 
 181 
 
 [i. 33- 
 [i. 41- 
 
 m-Bromo-toluol 
 p-Bromo-toluol 
 
 CH 3 [i q 
 
 CH 3 [i; 
 
 C 6 H 4 [ 3 ]Br 
 C 6 H 4 [ 4 ]Br 
 
 - 4 o 
 
 +28 
 
 183 
 i8 4 
 
 [I, 2]- 
 
 o-Iodo-toluol 
 
 CH 3 [i]C 6 H 4 [2]I 
 
 
 20 4 
 
 [i, 31- 
 
 m-Iodo-toluol 
 
 CH 3 [i]C 6 H 4 [ 3 ]I 
 
 
 20 4 <> 
 
 [i, 41- 
 
 p-Iodo-toluol 
 
 CH 3 [i]C 6 H 4 [ 4 ]I 
 
 35 
 
 211 
 
 o-, m-, and p-Fluoro-toluols have been prepared by the same 
 methods as fluoro-benzol. On chlorinating or brominating toluol in 
 the cold, or in the presence of iodine or FeCl 3 , para- and ortho-com- 
 pounds are produced, in nearly equal quantities. The p-chloro-toluol 
 may be separated from the o-compound by heating to 150 with 
 sulphuric acid, when the o-compound forms a sulpho-acid. 
 
 All the monochloro-, monobromo-, and mono-iodo- toluols may be 
 obtained pure by decomposition of the diazo-compounds (q.v.) obtained 
 from the three amido-toluols or toluidinenes. The o- and p-chloro- 
 toluols are easily obtained from the corresponding toluidins. The 
 m-bromo-toluol has also been obtained by brominating aceto-p- 
 toluidin to m-brom-aceto-p-toluidin and then replacing the amido- 
 group by hydrogen. 
 
 The m-chloro-toluol has also been obtained from 3-methyl-A 2 - 
 
 keto-R-hexene, easily prepared from methylene-diaceto-acetic ester. 
 
 In this process tetrahydro-m-dichloro-toluol is first prepared by 
 
 means of PC1 5 , and then it splits into HC1 and dihydro-m-chloro-toluol. 
 
 VOL. n. F 
 
66 
 
 ORGANIC CHEMISTRY 
 
 Bromine withdraws two H atoms from this body, and m-chloro-toluol 
 is formed (B. 27, 3019) : 
 
 CH 3 CH 3 CH 3 CH 3 
 
 C=CH CO > C=CH CC1 2 >C=-CH CC1 ^C=CH CC1 
 
 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH CH=CH CH 
 
 If we start from ethylidene-binaceto-acetic ester, we obtain [i, 3, 5]- 
 chloro-m-xylol (B. 29, 310) ; and [i, 3, 6]-chloro-cymol has been 
 similarly obtained from menthone or keto-hexahydro-p-cymol (B. 29, 
 
 3*4). 
 
 The iodoso- and iodo-compounds corresponding to p-iodo-toluol 
 are known (B. 26, 358 ; 27, 1903). 
 
 For the halogen toluols their transformation into solid nitro-halogen 
 toluols, and their oxidation to the halogen benzoic acids of known 
 constitution, are characteristic. Chromic acid oxidises the m- and p- 
 halogen toluols to the corresponding carboxylic acids, but it com- 
 pletely burns up the o-halogen toluols. By boiling with dilute HNO 3 , 
 by potassium permanganate or potassium ferricyanide, all the three 
 isomers, including the ortho-compounds, are converted into carboxylic 
 acids. 
 
 Of aromatic di-halogen toluols with similar halogens six isomers are 
 possible. The six isomeric dichloro-toluols are known (B. 29, R. 867). 
 They are isomeric with benzal chloride C 6 H 5 CHC1 2 , and the three 
 chloro-benzyl chlorides C1C 6 H 4 CH 2 C1. For particulars of the higher 
 chlorination products of toluol, see C. 1902, II. 1178 ; 1904, II. 1292, 
 etc. The six isomeric dibromo-toluols and di-iodo-toluols have all 
 been obtained (C. 1910, I. 525). Pentabromo-toluol is prepared from 
 suberane and bromine. The six isomeric tribromo-xylols are all 
 known (C. 1906, II. 1831). 
 
 The following table contains the easily prepared bromo-derivatives 
 of polymethyl-benzols : 
 
 Name. 
 
 M.p. 
 
 B.p. 
 
 [i, 2, 4]-Bromo-o-xylol. 
 
 
 
 2 
 
 214 
 
 [i, 3, 4]-Bromo-m-xylol 
 
 
 
 
 203 
 
 [i, 2, 4]-Bromo-p-xylol 
 
 
 
 + 9 
 
 200 
 
 Tribromo-hemimellithol 
 
 
 
 245 
 
 
 [i, 2, 4, 3]-Monobromo-pseudocumol 
 
 
 
 
 237 
 
 [i, 2, 4, 3, 6]-Dibromo-pseudocumol 
 
 
 
 64 
 
 293 
 
 Tribromo-pseudocumol 
 
 
 
 224 
 
 
 Monobromo-mesitylene 
 
 
 
 
 - i 
 
 2^5 
 
 Dibromo-mesitylene 
 
 
 
 
 
 + 60 
 
 285 
 
 Tribromo-mesitylene 
 
 
 . 
 
 
 
 224 
 
 
 Monobromo-prehnitol 
 
 
 
 
 
 30 
 
 265 
 
 Dibromo-prehnitol 
 
 
 . 
 
 
 
 210 
 
 
 Monobromo-isodurol 
 
 
 
 
 
 
 253 
 
 Dibromo-isodurol 
 
 
 . 
 
 
 
 20Q 
 
 
 Monobromo-durol 
 
 
 . 
 
 
 
 61 
 
 262 
 
 Dibromo-durol 
 
 
 . 
 
 
 
 199 
 
 317 
 
 Bromo-pentamethyl-benzol .... 
 
 1 60 
 
 289 
 
 It is also remarkable that concentrated sulphuric acid can transfer 
 bromine atoms instead of alkyl groups. It thus converts monobromo- 
 durol first into dibromo-durol and then into lurol (B. 25, 1526). 
 
NITROGEN DERIVATIVES OF BENZENE HYDROCARBONS 67 
 
 A number of iodinated alkyl-benzols have, like iodo-benzol itself, 
 been prepared by means of sulphur iodide and HNO 3 (see B. 33, 2875). 
 
 Concerning the influence of alkyl groups in the " reverse substitu- 
 tion " of iodine in iodinated benzols, see /. pr. Ch. 2, 65, 564. 
 
 3. Nitrogen Derivatives of Benzene Hydrocarbons in which the 
 nitrogenated residue is connected with the benzene nucleus by 
 nitrogen linking. 
 
 These compounds may be classified by the number of nitrogen 
 atoms contained in the residues. The first class is formed by com- 
 pounds in which the nitrogen group only contains one nitrogen atom. 
 This is headed by the mYro-compounds, so characteristic of the benzene 
 derivatives in general, which form the bases for obtaining the succeed- 
 ing groups. Then come the amido-compounds, which comprise the 
 generators of many coal-tar dyes and aromatic bodies of therapeutic 
 importance. A link between both groups is formed by the nitroso- 
 and the ft-hydroxylamine compounds. 
 
 The second class is formed by the compounds in which the nitro- 
 genated residue contains two or more N atoms mutually linked. Two 
 N atoms are carried by the nitro- amines, the nitroso-p-hydroxyl- 
 amines, the nitrosamines, the azoxy-compounds^ the hydrazins, the 
 diazo- and the azo-compounds. Three N atoms are carried by the 
 mVroso-hydrazins, the diazo-amido-compounds, and the azo-imido- 
 compounds ; four N atoms by the diazo-kydrazides or buzylene com- 
 pounds, and the tetrazones ; five N atoms by the bis-diazo-amido- 
 compounds ; and eight N atoms by the bis-diazo-tetrazones or octazones. 
 
 Our knowledge of some of these classes of bodies has acquired the 
 greatest importance, even for the chemistry of the inorganic nitrogen 
 compounds. If we imagine these nineteen groups of aromatic nitrogen 
 compounds derived from the inorganic nitrogen compounds obtained 
 by replacing the aromatic residues by hydrogen, then out of the nineteen, 
 only six occur free or in inorganic compounds, and these are printed in 
 heavy type in the following list : 
 
 1 . A^ro-compounds . . . derived from H.N0 2 
 
 2. Nitroso-compounds . . ,, H.NO 
 
 3. 0-Hydroxylamine-compounds , , H.NHOH 
 
 H.NH 2 
 H.NH.N0 2 
 H.N(OH).NO 
 H.NH.NO 
 H.N = N.OH 
 
 H.NH.NO or H.N(OH) ; N 
 9. Azo-compounds . ,, H.N=N.H 
 
 4. Amido-compounds 
 
 5. Nitro-amines 
 
 6. Nitroso-ft-hydroxylamines 
 
 7. Nitrosamines 
 
 8. .Dia^o-compounds 
 
 10. A zoxy -compounds 
 
 n. Hydrazins .... 
 
 12. Nitroso-hydrazins 
 
 13. Diazo-amido-compounds 
 
 1 4 . Diazo-oxy-amido-compounds . 
 
 15. Diazo-imido-compounds 
 
 1 6. Diazo-hydrazo- or Buzylene com- 
 
 pounds 
 
 17. Tetrazones .... 
 
 1 8. Bis-diazo-amido-compounds . 
 
 19. Bis-diazo-tetrazone or Octazone 
 
 H.N 
 
 N.H 
 
 H.NH.NH 2 
 
 H.N(NO).NH 2 
 H.N = N.NH 2 
 H.N = N NHOH 
 
 H.N = N.NH.NH, 
 H.NH.N = N.NH2 
 
 H.N = N NH N = N.H 
 
 H.N : N.NH.N : N.NH.N : NH. 
 
68 ORGANIC CHEMISTRY 
 
 The first three groups will be dealt with in the succession shown, 
 but the others will be arranged by their genetic rather than their 
 systematic relations, as follows : Nitroso-jS-hydroxylamines ; Amido- 
 compounds ; Nitroso - amines ; Nitro - amines ; Diazo - compounds ; 
 Diazo-amido-compounds ; Bis-diazo-amido-compounds ; Diazo-oxy- 
 amido- and Azo-imido-compounds ; Azoxy- and Azo-compounds ; 
 Hydrazines ; Nitroso - hydrazines ; Tetrazones ; Diazo - hydrazo- or 
 Buzylene compounds ; and Octazones. 
 
 i. NITRO-DERIVATIVES OF BENZENE AND THE ALKYL-BENZOLS. 
 
 Benzene and the alkyl-benzols which contain H atoms attached to 
 the nucleus easily give nitro-derivatives under the action of nitric acid : 
 
 C 6 H 6 +N0 2 OH=C 6 H 5 N0 2 +H 2 0. 
 
 In these compounds of a more or less yellow colour the nitrogen of 
 the nitro-group is directly linked with a carbon atom, as in nitro- 
 methane, for on reduction we obtain amido-compounds : 
 
 C 6 H 6 N0 2 +6H=C 6 H 5 NH 2 + 2 H 2 0. 
 
 In the previous chapter it was stated that all the H atoms of ben- 
 zene may be replaced by chlorine and bromine. This does not apply 
 to the nitro-groups. The two first nitro-groups enter without diffi- 
 culty, but the third encounters more resistance, and it has not been 
 found possible to introduce more than three nitro-groups into a 
 benzene derivative. 
 
 A mixture of one part HNO 3 and two parts H 2 S0 4 acts more 
 energetically than HNO 3 alone, as the sulphuric acid withdraws water. 
 Di- and trinitro-products are mostly obtained thus. A less complete 
 nitrogenation is attained by first dissolving in glacial acetic acid and 
 chloroform (B. 42, 4151). 
 
 The more alkyl groups are contained in a benzene hydrocarbon, 
 the more easily it is nitrogenated. The production of nitro-phenols 
 during such nitrogenation may be explained by assuming an addition 
 of HNO 3 to double links of the benzene ring, and the liberation of 
 HNO 2 on the one hand and H 2 O on the other (B. 24, R. 721 ; 42, 4152). 
 Such unstable addition products may also be the cause of the dark- 
 brown colouring at first observed during nitrogenation. On heating 
 with dilute HNO 3 the nitro-group enters the aliphatic side chain. Such 
 compounds are dealt with later in connection with the corresponding 
 alcohols (B. 27, R. 193 ; C. 1899, I- I2 37)- 
 
 An admirable means of nitrogenation has been discovered in ben- 
 zoyl and acetyl nitrate, suitable for some cases (B. 39, 3798 ; C. 1907, 
 I. 1025). It avoids the generation of water which accompanies nitro- 
 genation with HNO 3 : 
 
 C 6 H 6 +C 6 H 5 COON0 2 ^C 6 H 5 N0 2 +C 6 H 6 COOH. 
 
 The action of A1 2 C1 6 upon the hydrocarbon mixed with ethyl 
 nitrate can also produce nitro-compounds (C. 1908, II. 403). 
 
 From the aromatic amines obtained by reduction of the nitro-com- 
 pounds the latter may be recovered through the intermediary of the 
 diazo-compounds, the nitrites of which yield nitro-bodies when treated 
 with cuprous oxide. Nitro-bodies have also been obtained by direct 
 
NITRO-DERIVATIVES OF BENZENE 
 
 69 
 
 oxidation from amines, e.g. nitro-benzol from aniline with K perman- 
 ganate, in which process /2-phenyl-hydroxylamine and nitroso-benzol 
 have been obtained as intermediate products (B. 32, 1675). 
 
 Properties and Behaviour. The nitre-hydrocarbons are only slightly 
 soluble in water, but they are soluble in concentrated HNO 3 , and are 
 precipitated from this solution by water. They are easily dissolved in 
 alcohol, ether, glacial acetic acid, etc. The nitre-products melt at rather 
 a higher temperature than the corresponding bromine derivatives. 
 
 Of greater importance is the easy reduction of the nitre-compounds. 
 As intermediate products of the reduction to amide-compounds the 
 nitroso-compounds and the j3-phenyl-hydroxylamines have been re- 
 tained. Both combine, under the influence of an alkali, to azoxy-com- 
 pounds, which are further reduced to azo- and hydrazo-compounds. 
 These genetic relations are represented by the scheme : 
 
 C 6 H 5 N0 2 >C 6 H 5 NO > C 6 H 6 NHOH > C,H 5 NH 2 
 
 Nitroso-benzol -Phenyl-hydroxylamine Aniline 
 
 C ' H f>o- 
 
 C e H 5 N/ 
 Azoxy-benzol 
 
 C,H 5 N 
 
 "* C 6 H 5 N 
 Azo-benzol 
 
 C 6 H 5 NH 
 
 C,H 5 NH 
 
 Hydrazo-benzol. 
 
 During the electrolytic reduction of nitre-bodies dissolved in sul- 
 phuric acid we obtain, besides amido-hydrocarbons, amido-phenols, 
 by transposition of the unstable j3-phenyl-hydroxylamines (B. 29, 
 R. 230). In HC1 solution p-chloraniline is formed by a similar process 
 (B. 29, 1894 ; C. 1907, I. 463). 
 
 About the electrolytic reduction of nitre-bodies, see also C.I 901, 
 I. 105, 149 ; B. 38, 4006 ; A. 355, 175, etc. 
 
 The easy reduction of nitro-bodies to substances useful in the 
 manufacture of coal-tar dyes has given them the position of im- 
 portant and indispensable intermediate products. 
 
 By oxidation with alkaline K ferricyanide solution, the polynitro- 
 benzols are easily converted into polynitro-phenols. Nitro-benzol, 
 on heating with powdered caustic potash, yields o-nitro-phenol and 
 azoxy-benzol ; m-nitro-toluol similarly yields m-nitro-o-cresol ; and 
 m-dinitro-benzol yields 2, 4-dinitro-phenol (B. 32, 3486 ; 34, 2444 ; 
 C. 1901, I. 149). 
 
 By heating with HC1 to 20O-300 the nitro-groups are replaced 
 by chlorine in many polynitro-hydrocarbons, and in some cases there 
 is a further chlorination (B. 29, R. 594). 
 
 NITRC-BENZOLS. The melting-points and boiling-points of the 
 known nitro-benzols are shown in the following table : 
 
 Name. 
 
 Formula. 
 
 M.p. 
 
 B.p. 
 
 
 tfitro-benzol 
 
 C 6 H 5 NO 2 
 
 + 5-72 
 
 209 (C. 1897, II. 
 
 547) 
 
 2]-, o-Dinitro-benzol 
 
 } ( 
 
 116 
 
 319 (773 mm.) 
 
 
 3]-, m-Dinitrc-benzol 
 
 IC 6 H 4 (N0 2 ) 2 - 
 
 90 
 
 303 (771 mm.) 
 
 
 4]-, p-Dinitro-benzol 
 
 j I 
 
 172 
 
 299 (777 mm -) 
 
 
 \ 2, 4]-, as-Trinitro-benzol 
 3 5]~f s-Trinitro-benzol . 
 
 }C 6 H 3 (N0 2 ) 3 { 
 
 57 
 
 121 
 
 
 
 ! 2 > 3 5]-Tetranitro-benzol 
 
 C,H 2 (N0 2 ) 4 
 
 116 
 
 
 
70 ORGANIC CHEMISTRY 
 
 Nitro-benzol C 6 H 5 NO 2 was discovered in 1834 b Y Mitscherlich 
 (Pogg. Ann. 31, 625), on treating benzene with nitric acid. It is also 
 formed during the oxidation of aniline. It is prepared in large quanti- 
 ties industrially, and worked for aniline and azo-benzol. For the in- 
 dustrial preparation of nitro-benzol a mixture of HNO 3 and H 2 SO 4 is 
 allowed to flow into benzene in cast-iron tubes, and kept stirred. 
 Nitro-benzol is a yellowish, highly refractive liquid of density 1-20 at 
 20, smelling of benzaldehyde or oil of bitter almonds, tasting sweet 
 in dilute aqueous solution, and acting as a poison, especially when 
 its vapour is breathed. Besides the dye industry, nitro-benzol is 
 also employed in the perfume industry, to give soap an odour of oil 
 of bitter almonds. In the laboratory it is often employed as a 
 solvent or an oxidiser (see Rosaniline and Quinolin). 
 
 DINITRO-BENZOLS C 6 H 4 (NO 2 ) 2 . On prolonged boiling of benzene 
 with fuming HNO 3 , or on short heating with HNO 3 and H 2 SO 4 , 
 m-dinitro-benzol is chiefly formed, together with the o- and p-forms, 
 which are more easily soluble in alcohol (B. 7, 1372). The meta-com- 
 pound is used in the dye industry for preparing m-phenylene-diamine. 
 
 p-Dinitro-benzol is also obtained from p-quinone dioxime by oxi- 
 dation ; and o-dinitro-benzol from the residues of preparation of 
 m-dinitro-benzol by dissolving in twice its weight of boiling HNO 3 
 and pouring into the five- or sixfold volume of cold HNO 3 , whereupon 
 the o-dinitro-benzol separates out in crystals (B. 26, 266). 
 
 The dinitro-benzols are capable of a lopsided reduction to nitro- 
 anilines (q.v.), which form the genetic link between phenylene-diamines 
 and dibromo-benzols, as well as phthalic acids. 
 
 Ortho-dinitro-benzol crystallises in plates, yields o-nitro-phenol on 
 boiling with NaHO, and o-nitraniline on heating with alcoholic ammonia. 
 Other o-dinitro- compounds behave in a similar manner. 
 
 Meta-dinitro-benzol, heated with K ferricyanide and NaHO, or 
 with powdered KHO, yields [i, OH, 2, 4] - dinitro - phenol and 
 [i, OH, 2, 6] - dinitro - phenol. On treating with alcoholic KCy an 
 NO 2 group is replaced by ethoxyl, with entry of a cyanogen group. 
 This produces [2] - nitro - [6] - ethoxy - benzo - nitrile (B. 17, R. 19) . 
 With alkali sulphite it forms, with reduction and sulphuration, 
 m-nitraniline-p-sulpho-acid (B. 29, 2448). 
 
 Para-dinitro-benzol, colourless needles. 
 
 By heating the dinitro-benzols with Cl or Br to 200 the nitro- 
 groups are replaced, wholly or partly, by halogens (B. 24, 3749). On 
 heating them with Na methylate or ethylate, a nitro-group is replaced 
 by a methoxy- or ethoxy-group (C. 1899, I. 1027). 
 
 TRINITRO-BENZOLS. [i, 3, 5]-, s-trinitro-benzol, white flakes, from 
 m-dinitro-benzol ; or by heating trinitro-benzoic acid ; or, syntheti- 
 cally, by oxidation of sodium nitro-malonaldehyde (B. 28, 2597 ; C.i899, 
 II. 609). [1,2,4]- or 0s-trinitro-benzol, from p-dinitro-benzol on 
 heating to 180 with HNO 3 and pyro-sulphuric acid. The s-trinitro- 
 benzol may be oxidised to picric acid or [i, OH, 2, 4, 6]-trinitro-phenol. 
 With aniline, naphthalin, etc., it forms additive compounds, and 
 similar compounds are furnished by m- and p-dinitro-benzol, trinitro- 
 toluol, etc. (B. 13, 2346 ; 16, 234 ; 39, 76 ; C. 1906, II. 1249). witn 
 aqueous alkalies the s-trinitro-benzol gives orange-coloured products, 
 probably through the formation of unstable salts ; with Na alcoholates 
 
NITRO-DERIVATIVES OF BENZENE 71 
 
 it forms additive compounds of a saline nature, from which water 
 regenerates trinitro-benzol quantitatively. They may be interpreted 
 as salts of " quinolic " nitro-acids : 
 
 CH 3 
 
 , T ^ 
 
 H N0 2 H \ONa 
 
 (cp. Quinols, and A. 323, 219 ; C. 1903, I. 707 ; B. 42, 2119). On 
 heating with Na alcoholate solution a nitro-group of the s-trinitro- 
 benzol is replaced by an alkoxyl group (C. 1901, I. 1289). 
 
 as-Tetranitro-benzol C 6 H 2 [i, 2, 3, 5](NO 2 ) 4 , yellow needles, formed 
 from dinitro-dinitroso-benzolby careful oxidation with HNO 3 (B. 34, 56). 
 
 NITRO-HALOGEX-BEXZOLS. Modes of formation: (i) Nitrogenation 
 of F-, C1-, Br-, and I-benzols ; p-mononitro-halogen-benzols are formed 
 mostly, also some o-compounds. (2) Treatment of nitro-benzols with 
 bromine or chlorine ; in polynitro-compounds a nitro-group is readily 
 replaced by halogen. (3) Conversion of dinitro-benzols into nitraniline, 
 and replacement of the amido-group by halogens by means of diazo- 
 compounds. (4) Formation from nitro-phenols with PC1 5 , producing 
 chloro-nitro-benzols. 
 
 The halogen-nitro-benzols form the transition from the dinitro-, 
 nitro-amido-, and diamido-benzols to thehalogen-amido- and dihalogen- 
 benzols, and are therefore important for recognising the relations 
 between the various di-substitution products of benzene : 
 
 N0 2 r H /N0 2 ~ H /NO., ~ M /NH 2 ~ /Br 
 
 - > - 
 
 When nitro-groups enter the benzene nucleus in ortho- or para- 
 position to a halogen atom, this halogen atom requires the capacity of 
 reacting with alkalies, like the halogen alkyls (Vol. I.), while a nitro- 
 group in the w^ta-position does not produce this effect (cp. C. 1903, I. 
 571). This rule is markedly shown by the behaviour of 1,2,4,6- 
 tetrachloro-3, 5-dinitro-benzol. In this substance only the halogen 
 atoms 2, 4, and 6 can be replaced by the residues NH 2 , NHC 6 H 5 , 
 OC 2 H 5 , etc., but not the chlorine atom in the m-position with regard 
 to the two nitro-groups (C. 1904, 1. 1408). The loosening of the halogen 
 linking is the more marked, the more nitro-groups enter the nucleus, so 
 that i, 3, 5, 6-trinitro-chloro-benzol or picryl chloride has the character 
 of an acid chloride. In some cases it is not the halogen, but a nitro- 
 group, which is split off; cp. sym. dinitro-chloro- and i-Cl-3, 4, 6-trinitro- 
 chloro-benzol. 
 
 We give here the melting-points of the isomeric mononitro-, fluoro-, 
 chloro-, bromo-, and iodo-benzols : 
 
 [i, 2] [i, 3] [i, 4l 
 
 C 6 H 4 F(N0 2 ) -8 +1-69 +26-5 (.1905,1.29,1230) 
 
 C 6 H 4 C1(N0 2 ) 32-5 48 83 (C. 1898, II. 238 ; 1903, I. 208) 
 
 C 6 H 4 Br(N0 2 ) 43-1 56 126 (B. 29, 788) 
 
 C 6 H 4 I(N0 2 ) 49 36 171-4 (B. 29, 1880) 
 
 Meta-chloro-nitro-benzol occurs in two physical modifications : 
 Cooled rapidly after melting, it melts at 23-7 ; but after a short time 
 it changes into the more stable modification melting at 44-2. A 
 similar behaviour is shown by p-nitro-fluoro-benzol, the two melting- 
 points being 21-5 and 26-5. 
 
72 ORGANIC CHEMISTRY 
 
 Of the numerous known nitro-halogen-benzols, we may mention 
 the [i, Cl, 3, 4] - dinitro - chloro - benzol, which occurs in three very 
 similar modifications, having melting-points 36-3, 37, and 38 (B. 9, 
 760 ; C. 1908, II. 1425). 
 
 sym. Dinitro-ehloro-benzol, m.p. 59, formed by chlorination of 
 m-dinitro-benzol. On heating with Na alcoholate solution it exchanges, 
 not the Cl atom, but an NO 2 group for an RO group, forming a nitro- 
 chloro-phenol ether (C. 1900, I. 1115 ; 1901, I. 1289). 
 
 An analogous behaviour is shown by [i, Cl, 3, 4, 6]-Trinitro-ehloro- 
 benzol, m.p. 116, obtained by further nitrogenation of [i, Cl, 3, 4]- 
 dinitro-benzol. By the action of ammonia, the nitro-group in the 
 3-position is replaced by the amido-group (B. 36, 3953). 
 
 [i, 2, 4, 5]-Diehloro - dinitro - benzol, m.p. 114, and [i, 2, 3, 4]- 
 Dichloro-dinitro-benzol, m.p. 55, are formed together during nitro- 
 genation of o-dichloro-benzol. On heating with ammonia, the former 
 exchanges a nitro-group, and the latter a Cl atom for the NH 2 group 
 (B. 37, 3892). 
 
 [i, 3, 5, 4, Cl]-Trinitro-chloro-benzol-picryl-chloride C 6 H 2 C1(NO 2 ) 3 , 
 m.p. 83, from picric acid by means of PC1 5 . The latter, with ammonia 
 solution, gives picramide C 6 H 2 (NH 2 )(NO 2 ) 3 , and, on boiling with soda, 
 picric acid is generated. 
 
 Picryl bromide C 6 H 2 (NO 2 ) 3 Br, m.p. 123, from bromo-dinitro- 
 benzol with HNO 3 (C. 1903, I. 963). 
 
 Dinitro-dichloro-benzols and their transformation products are 
 described, C. 1902, II. 513 ; 1903, I. 503, 511 ; Dinitro-trichloro- 
 benzol, m.p. 130, see B. 29, R. 1155. 
 
 Of the six isomeric dibromo-nitro-benzols, five can be obtained by 
 direct nitrogenation of the three dibromo-benzols : 
 
 2]-Dibromo-4-nitro-benzol, m.p. 58 Chief product. 
 
 2]-Dibromo-3-nitro-benzol, ,, 85-2 By-product. 
 
 3]-Dibromo-4-nitro-benzol, ,, 61 Chief product. 
 
 3]-Dibromo-2-nitro-benzol, ,, 82 By-product. 
 4]-Dibromo-i-nitro-benzol, ,, 85 
 
 o-Dibromo-benzol i . 
 
 2. 
 
 m-Dibromo-benzol i . 
 
 2 - 
 
 p-Dibromo-benzol [ 
 
 The missing [i, 3]-dibromo-5-nitro-benzol, m.p. 104-5, was prepared 
 by Korner (J. 1875, 306) from the dibromo-p-nitraniline by eliminating 
 the amido-group. Concerning the transformation of the dibromo- 
 nitro-benzols into tribromo-benzols, and their significance concerning 
 the constitution of the three dibromo-benzols, see above. 
 
 NITRO-TOLUOLS. [i, 2]-, c-Nitro-toluol CH 3 [i]C 6 H 4 [2]N0 2 , two 
 modifications, m.p. 9 and 4, b.p. 218 ; and [i, 4]-, p-Nitro-toluol 
 CH 3 [i]C 6 H 4 [4]NO 2 , m.p. 54, b.p. 230, by nitrogenation of toluol. 
 They are separated by fractional distillation, and, on reduction, they 
 yield the industrially important toluidins. On nitrogenation at 55, 
 5*5 times as much p- as o-nitro-toluol is produced (B. 26, R. 362), and 
 even at higher temperatures chiefly p-nitro-toluol is obtained, with 
 fuming nitric acid, while nitro-sulphuric acid, at low temperatures, 
 gives about 66 per cent, o-nitro-toluol. 
 
 On further nitrogenation of o- and p-nitro-toluol we obtain : [2,4]- 
 dinitro-toluol, m.p. 70 ; [2,5]-dinitro-toluol, m.p. 48 ; and [2,4,6]- 
 trinitro-toluol, m.p. 82 (B. 21, 433 ; 22, 2679). 
 
 We must note the transformation of o-nitro-toluol into anthranilic 
 acid by heating with an alkaline hydroxide, whereby o-nitroso-benzyl 
 
NITRO-PRODUCTS OF ALKYL-BENZOLS 73 
 
 alcohol and anthranile have been isolated as intermediate products 
 (C. 1908, II. 210). The reaction passes through the following phases : 
 
 Similarly, we obtain from o-nitro-toluol-sulpho-acid anthranile 
 sulpho-acid (C. 1903, I. 371), and, by heating o-nitro-toluol with Br to 
 170, dibromo-anthranilic acid. 
 
 On boiling with HgO in an alkaline solution, o-nitro-toluol yields 
 a mono- and a di-mercuric compound. The latter probably has the 
 formula NO 2 [i]C 6 H 4 [2]CH<^: g ^>O. It forms dark-yellow crystals, which 
 
 decompose above 220, and may be smoothly split up in the cold by 
 means of concentrated HC1 into HgCl 2 and anthranile (q.v.) (B. 40, 
 4209 ; C. 1908, I. 1346) : 
 
 p-Nitro- and 2, 4-dinitro-toluol also react with HgO. 
 
 [1,3]-, m-Nitro-toluol CH 3 [i]C 6 H 4 [3]NO 2 , m.p. 16, b.p. 230, is 
 formed on nitrogenating aceto-p-toluidin and replacing the amido- 
 group by hydrogen (B. 22, 831). On further nitrogenation of m-nitro- 
 toluol we obtain [3,4]-dinitro-toluol, m.p. 61, and [3,5]-dinitro-toluol, 
 m.p. 92 (B. 27, 2209). 
 
 NITRC-PRODUCTS OF ALKYL-BENZOLS. 
 
 On account of the facility with which the aromatic nitro-compounds 
 are produced, many of them are suitable for determining their funda- 
 mental hydrocarbons. Some of them may here be enumerated : 
 
 [4]-Nitro-o-xylol NO 2 [4]C 6 H 3 [i, 2](CH 3 ) 9 , m.p. 29 (B. 17, 160 ; 
 18, 2670). [4,5]- and [4, 6]-Dinitro-o-xylol, m.p. 116 and 76 
 (B. 35, 628). 
 
 [5]-Nitro-m-xylol, m.p. 74. [2, 4]-Dinitro-m-xylol, m.p. 82. 
 [2, 6]-Dinitro-m-xylol, m.p. 93. [2,4,6]-Trinitro-m-xylol, m.p. 182 
 (B. 17, 2424). [4, 5, 6]-Trinitro-m-xylol, m.p. 125 (C. 1906, II. 29; 
 1909, I. 1320). 
 
 [2]-Nitro-p-xylol, b.p. 239 (B. 18, 2680). [2, 6]-Dinitro-p-xylol, 
 m.p. 123, and [2, 3]-Dinitro-p-xylol, m.p. 93, form a double compound 
 of m.p. 99 (B. 15, 2304). [2, 3, 6]-Trinitro-p-xylol, m.p. 137 (B. 
 
 19,145). 
 
 [2, 4]-Dinitro- ethyl -benzol, b.p. 10 163. [2, 4, 6] -Trinitro - ethyl- 
 benzol, m.p. 37 (B. 42, 2633). 
 
 Nitro-mesitylene NO 2 [2]C 6 H 2 [i, 3, 5](CH 3 ) 3 , m.p. 44 (6.33,3625). 
 Dinitro-mesitylene, m.p. 86. Trinitro-mesitylene, m.p. 232 (B. 29, 
 2201). 
 
 Nitro-pseudocumol NO 2 [5]C 6 H 2 [i, 2, 4](CH 3 ) 3 , m.p. 71. Dinitro- 
 pseudocumol (XO 2 ) 2 [3,5]C 6 H[i,2,4f(CH 3 ) 3 , m.p. 172. [3, 5, 6]-Trinitro- 
 pseudocumol (NO 2 ) 3 [ 3 , 5, 6]C 6 [i, 2, 4l(CH 3 ) 3 , m.p. 185 (B. 42, 3608). 
 
 [4, 5, 6]-Trinitro-v-trimethyl-benzol (NO 2 ) 3 [4, 5, 6]C 6 [i, 2, 3] (CH 3 ) 3 , 
 m.p. 209 (B. 19, 2517). 
 
74 ORGANIC CHEMISTRY 
 
 Nitro-prehnitol NO 2 [5]C 6 H[i, 2, 3, 4](CH 3 ) 4 , m.p. 61 (B. 21, 905). 
 Dinitro-prehnitol, m.p. 178. Dinitro-isodurol (NO 2 ) 2 [4, 6]C 6 [i, 2, 3, 5] 
 (CH 3 ) 4 , m.p. 156. Dinitro-durol (NO 2 ) 2 [3, 6]C 6 [i, 2,4, 5](CH 3 ) 4 , m.p. 
 205. 
 
 Nitro-pentamethyl-benzol, m.p. 154 (B. 42, 4162). 
 
 [2, 4, 6]-Trinitro-<H>utyl-toluol (NO 2 ) 3 [ 2 , 4, 6]C 6 H[i]CH 3 [ 3 ]C(CH 3 ) 3 , 
 m.p. 96- 97, smells intensely of musk, and is marketed as " artificial 
 musk " (B. 24, 2832). 
 
 NITRO-HALOGEN DERIVATIVES OF THE ALKYL-BENZOLS. 
 
 A large number of such compounds have been prepared. 
 
 2-Chloro-5-nitro-toluol, m.p. 44, and 4-ehloro-2-nitro-toluol, m.p. 
 38, by nitrogenation of o- and p-chloro-toluol respectively (B. 19, 
 2438 ; 20, 199). 3-Chloro-4-nitro-toluol, m.p. 55, from nitro-m- 
 toluidin. For further halogen-nitro-toluols, see B. 37, 1018. 
 
 2, 4, 6-Trinitro-5-chloro-toluol, m.p. 148, is formed, besides the 
 2, 4-dinitro-compound, on nitrogenation of m-chloro-toluol. It is a 
 homologue of picryl chloride. Here also the halogen is exceedingly 
 reactive, and exchangeable for numerous other groups. 
 
 Nitro-bromo-durol, m.p. 178, by nitrogenation of bromo-durol 
 with nitro-sulphuric acid in chloroform solution. Very peculiar is the 
 action of fuming nitric acid upon bromo-durol, leading to dinitro- 
 durylic bromide, with displacement of the bromine atom and oxidation : 
 TT CH 3 CH 3 CH 3 COBr 
 
 H CH 3 CH 3 Br - -* N 2 CH 3 CH 3 N0 *- 
 
 RULES OF SUBSTITUTION. 
 
 Formation of Di-derivatives. Chlorination and bromination of 
 benzene and toluol, nitrogenation of monohalogen benzols and of 
 toluol, give rise almost entirely to p- and o-di-derivatives, while nitro- 
 genation of benzene produces chiefly m-dinitro-benzol. Phenol and 
 aniline behave like toluol : p- and o-di-derivatives are mainly formed. 
 On the other hand, benzol sulpho-acid C 6 H 5 SO 3 H, benzoic acid 
 C 6 H 5 COOH, benzaldehyde C 6 H 5 CHO, benzo-nitrile C 6 H 5 CN, aceto- 
 phenone C 6 H 5 CO.CH 3 , and a few other compounds, with so-called 
 side groups, form mostly m-combinations. The substituents contained 
 in the mono-derivatives therefore determine the place of further sub- 
 stitution. And it is not immaterial in what succession the substituents 
 are introduced. Nitrogenation of chloro-benzol yields chiefly p-nitro- 
 chloro-benzol, while chlorination of nitro-benzol produces mainly 
 m-nitro-chloro-benzol. 
 
 Concerning the dependence of substitution processes upon atomic, 
 and radicle, magnitudes of the substituents, see B. 23, 130. 
 
 The following rule is given by Crum Brown and J. Gibson : If the 
 hydrogen link of the atom or radicle attached to the benzene nucleus 
 in the mono-derivative cannot be oxidised direct, i.e. in one operation, 
 to the corresponding hydroxyl compound, a further substitution gives 
 o- and p-derivatives, otherwise m-derivatives (B. 25, R. 672). 
 
 The following rule attempts an explanation of the various regu- 
 larities of substitution. The second substituent enters the o- or p- 
 position when the first substituent is attached, with much valence 
 
NITROSO-DERIVATIVES OF BENZENE 75 
 
 energy, to the benzol-hydrocarbon atom, since there is then a greater 
 amount of surplus energy attached to the C atom ; when the first 
 substituent is loosely bound, the m-position has more surplus energy, 
 and the substitution will take place there (/. pr. Ch. 2, 66, 321 ; cp. 
 C. 1906, I. 458). 
 
 Formation of Tri-derivatives. On further substitution (chlorination, 
 nitrogenation) of the ortho- and para-di-derivatives, the substituent 
 groups enter the para- and ortho-positions respectively, so that the 
 di-derivatives [i, 2], and [i, 4] become tri-derivatives [i, 2, 4] (A. 192, 
 219). From the meta-di-derivatives [i, 3] the [i, 3, 4] and [i, 2, 3]- 
 tri-derivatives are obtained. If both substituent groups are of strongly 
 acid character, as in m-dinitro-benzol [1,3, 5] -derivatives are formed. 
 
 Formation of Tetra-derivatives. If further substitution takes place 
 in an unsymmetrical tri-derivative [1,2,4], unsymmetrical tetra- 
 derivatives [i, 2, 4, 6] are usually produced. Aniline, phenol, etc., 
 become trichloro- or trinitro-derivatives, in which the entering groups 
 are in the meta-position [2, 4, 6] = [i, 3, 5] with respect to each other. 
 If from these the groups OH and NH ? are eliminated, symmetrical 
 tri-derivatives C 6 H 3 X 3 [i, 3, 5] are obtained. 
 
 2. NITROSO-DERIVATIVES OF BENZENE AND THE ALKYL-BENZOLS. 
 
 Mononitroso-derivatives of benzene hydrocarbons cannot be 
 obtained from the benzols by substitution. They are produced : 
 
 (1) by oxidation of the corresponding j8-hydroxylamine derivatives 
 with K bichromate and sulphuric acid, ferric chloride, or atmospheric 
 oxygen : 
 
 C 6 H 5 NHOH+0=C 6 H 5 NO+H 2 ; 
 
 (2) from anilines by oxidation with sulpho-mono-per-acid (B. 32, 1675) ; 
 
 (3) by electrolytic reduction of nitro-benzol without a membrane, 
 using neutral electrolytes, e.g. solutions of Na, Mg, or Al sulphate. 
 The formation of nitroso-benzol seems, in this case, to be secondary, 
 the primary jS-phenyl-hydroxylamine formed at the cathode being 
 oxidised to nitroso-benzol at the anode (C. 1908, 1. 911). The nitroso- 
 compounds form colourless crystals of great volatility, coloured green, 
 when melted or dissolved. This change of colour is probably due to 
 the fact that the molecules, dimeric in the solid state, become dis- 
 sociated into simple molecules on melting or dissolving (B. 34, 3877). 
 By oxidation the nitroso-benzols give nitro-bodies ; by reduction, 
 amido-bodies. With aromatic amines they condense to azo-bodies 
 with elimination of water ; with jS-phenyl-hydroxylamines, to azoxy- 
 bodies ; with hydroxylamine, to so-called isodiazo-benzols ; with phenyl- 
 hydrazine, to diazo-oxy-amido-compounds ; with the salts of nitro- 
 hydroxylaminic acid (Vol. I.), or benzol-sulpho-hydroxamic acid, they 
 form j3-phenyl-nitroso-hydroxylamines (Bamberger, B. 28, 245, 1218 ; 
 29, 102 ; 32, 3554 ; C. 1904, I. 24) : 
 
 C 6 H 5 NO+NH 2 .C 6 H 5 =C 6 H 5 N : N.C 6 H 6 +H 2 O 
 C 6 H 5 NO+NH(OH).C 6 H 5 =C 6 H 5 N~ - -NC 6 H 5 +H 2 O 
 
 C 6 H 5 NO +NH 2 .OH = C 6 H 5 N : N.OH +H 2 O 
 
 C 6 H 5 NO+NH 2 .NHC 6 H 5 = C 6 H 5 N(OH)N : NC 6 H 5 (+ 2 H) 
 C 6 H 5 NO+HON : NO 2 Na = C 6 H 5 N(OH)NO+NO,Na. 
 
76 ORGANIC CHEMISTRY 
 
 With substances containing CH 2 groups which have become reactive 
 through the vicinity of acid-forming radicles, the nitroso-benzols yield 
 ketone-aniles with elimination of water, e.g. 
 
 <p-\r 
 H =C 6 H 5 N : 
 
 (B. 34, 494). By concentrated H 2 SO 4 the nitroso-benzols are 
 polymerised like aldol, forming p-nitroso-diphenyl-hydroxylamines 
 NOCeH 4 N(OH)C 6 H 5 (B. 31, 1513; 32, 219). Nitroso-benzol in these 
 reactions strikingly resembles the aldehydes, especially benzaldehyde 
 C 6 H 5 CHO (q.v.), from which it is distinguished by the CH group being 
 replaced by a nitrogen atom. With diazo-methane (Vol. I.) the nitroso- 
 benzols form addition products, which give off N, and pass into the 
 N-phenyl-ether of glyoxime (B. 30, 2791). 
 
 NITROSO-BENZOL C 6 H 5 NO, m.p. 68, first obtained in solution by 
 the action of nitrosyl bromide upon mercury diphenyl (v. Baeyer, 1874). 
 Now prepared by oxidation of j8-phenyl-hydroxylamine or aniline, or by 
 electrolytic reduction of nitro-benzol. Produced in small quantities 
 with other bodies by oxidation of diazo-benzol chloride ; also from 
 diazo-benzol perbromide with alkalies, and by distillation of azoxy- 
 benzol (B. 27, 1182, 1273). Illumination completely decomposes 
 nitroso-benzol in benzene solution : besides some resins, azoxy-benzol, 
 nitro-benzol, aniline, and o-oxyazo-benzol are formed (B. 35, 1606). 
 
 o-, m-, p-Nitroso-toluol CH 3 .C 6 H 4 .NO, m.p. 72, 53, 48. 2, 3-, 
 2, 4-, 2, 5-, 2, 6-, and 3, 4-Nitroso-xylol (CH 3 ) 2 C 6 H 3 NO melt at 91, 41, 
 101, 141, and 45. Nitroso-mesitylene (CH 3 ) 3 [2, 4, 6]C 6 H 2 NO, m.p. 
 122, best obtained from amido-mesitylene (mesidin) with sulpho-mono- 
 per-acid (A. 316,257, etc.). p-Chloro- and p-Bromo-nitro-benzol, m.p. 
 87 and 92. 
 
 o-, m-, and p-Nitro-nitroso-benzol, m.p. 126, 90, and 119, by 
 oxidation of the three nitranilines with sulpho-mono-per-acid (B. 36, 
 3803 ; 38, 4011). o- and p-Nitro-nitroso-benzol are also obtained by 
 reduction of o- and p-dinitro-benzol by hydroxylamine and stannous 
 oxide, in strongly alkaline methyl-alcoholic solution. This at first gives 
 strongly coloured alkali salts of a dinitronic acid resembling quinone, 
 
 C 6 H 4 ^ NOOK , from which acidulation liberates water and produces the 
 
 nitro-nitroso-benzols. Similarly, o-nitro-nitroso-p-xylol, m.p. 130-5, 
 from o-dinitro-p-xylol. m-Dinitro-benzol is not reduced under similar 
 conditions, but undergoes substitution with formation of dinitro-amido- 
 compounds (B. 39, 2526, 2533). 
 
 Trinitro-nitroso-benzol (NO 2 ) 3 [2, 4, 6]-C 6 H 2 NO, m.p. 198 (B. 34, 
 
 59)- 
 
 2-Nitro-6-nitroso-toluol, m.p. 117, 2-Nitro-4-nitroso-toluol, m.p. 87 
 
 (B. 40,3331). 
 
 p-Dinitroso-derivatives are formed by oxidation of p-quinone di- 
 oximes in alkaline solution with potassium ferricyanide, e.g. p-Dinitroso- 
 toluol CH 3 [i]C 6 H 3 [2, 5](NO) 2 , m.p. 133, from tolu-quinone dioxime 
 CH 3 C 8 H 3 (NOH) 2 , yellow needles with a suffocating odour of quinone, 
 converted by fuming nitric acid into p-dinitro-toluol, and by hydro- 
 xylamine chloride into tolu-quinone dioxime (B. 21, 734, 3319). 
 
 o-Dinitroso-derivatives are obtained from o-nitro-diazo-imides, by 
 heating, and elimination of N. 
 
jS-ALPHYL- OR ARYL-HYDROXYLAMINES 77 
 
 o-Dinitroso-benzol C 6 H 4 [i, 2](NO) 2 , m.p. 72, from o-nitro-diazo- 
 benzol-imide at 90, yields on reduction o-quinone dioxime (A. 307, 28). 
 
 m-Dinitroso-benzol C 6 H 4 [i, 3](NO) 2 , m.p. 146-5, formed, besides 
 m-nitro-nitroso-benzol, during reduction of m-dinitro-benzol, with zinc 
 dust, and glacial acetic acid in alcoholic solution (B. 38, 1899). 
 
 1, 2, 3, 4-Tetranitroso-benzol C 6 H 2 (NO) 4 , m.p. 93, from diquinoyl- 
 tetroxime by oxidation with sodium hypochlorite (B. 32, 505). 
 
 Dinitro-dinitroso-benzol C 6 H 2 (NO 2 ) 2 (NO) 2 , m.p. 133, golden flakes, 
 from picrvl chloride with hydroxylamine in acetic solution. By oxida- 
 tion it yields as-tetranitro-benzol (B. 34, 55). 
 
 3. j3-ALPHYL- OR ARYL-HYDROXYLAMINES.* 
 
 These very reactive substances are obtained as intermediate pro- 
 ducts in the reduction of nitro- and nitroso-benzols. They are very 
 sensitive to alkalies and acids, and they are therefore prepared by 
 means of neutral reducing agents, as by the action of zinc dust, and 
 sal ammoniac solution, upon nitro-benzols, or of Al amalgam and water 
 on the etheric solutions of nitro-benzols (B. 29, 494, 863, 2307). 
 
 Particularly straightforward is the electrolytic reduction of the 
 nitro-com pounds in acetic solution with Na acetate (B. 38, 3076). 
 With alcoholic ammonium sulphide it is easy to obtain /S-aryl-hydro- 
 xylamine. Polynitro-compounds in this case yield nitro-aryl-hydro- 
 xylamines by partial reduction (B. 41, 1936). Aniline is oxidised to 
 jS-phenyl-hydroxylamine by mono-sulpho-per-acid (B. 32, 1675). 
 
 The aryl-hydroxylamines reduce ammoniacal silver solution and 
 Fehling's solution. They energetically absorb atmospheric oxygen in 
 aqueous solution, especially in the presence of alkali. Hydrogen per- 
 oxide is thus generated, and the hydroxylamines are first oxidised to 
 nitroso-benzols, which, however, mostly combine with the unchanged 
 aryl-hydroxylamine to azoxy-benzols : 
 
 C 6 H 5 NO+C 8 H 5 NHOH=C 6 H 5 N, -NC,H 5 +H,O. 
 
 \O/ 
 
 By ortho- and />flra-position methyl groups this reaction is retarded, 
 and in mesityl-hydroxylamine it is entirely suspended (A. 316, 257). 
 
 With diazo-benzol solutions the aryl-hydroxylamines yield diazo- 
 oxy-amido-compounds, e.g. C 6 H 5 N(OH)N 2 C 6 H 5 ; this reaction is also 
 hindered by o- and p-methyl groups. 
 
 Sulphuric acid transposes phenyl-hydroxylamine, and hydro- 
 xylamines in a free para-position, into p-amido-phenols : 
 
 C 6 H 5 NHOH - --> HO[4]C 6 H 4 [i]NH 2 . 
 
 If the para-position is occupied by a methyl group, transposition 
 occurs all the same ; but so-called " quinols " are produced with rejec- 
 tion of NH 3 . These quinols are closely related to the quinones (q.v.), and 
 may easily pass by further atomic displacement into methylated hydro- 
 quinones, e.g. 
 
 CH 3 H H NHOH 
 
 3 H H 
 
 * " Alphenyl " is a contraction of " alkyl phenyl " C ;/ H 2 ,, +J C 6 H 4 (Bamberger) . 
 The word " aryl "= aromatic radicle has been lately proposed for these residues 
 (Vorlander, J.'pr. Ch. 2, 59, 247). 
 
78 ORGANIC CHEMISTRY 
 
 Concentrated sulphuric acid transforms phenyl-hydroxylamine into 
 p-amido-phenol-o-sulpho-acid. Concentrated nitric acid transforms 
 m-tolyl-hydroxylamine into chloro-toluidines (B. 33, 3600 ; 34, 61 ; 
 35, 3697). Cp. the similar transpositions of aromatic nitramines, 
 nitrosamines, and chloramines, into p-nitro-, nitroso-, and chlor-aniline. 
 
 With aldehydes, e.g. benzaldehyde, the aryl-hydroxylamines reject 
 
 C H N CHC H 
 
 water, and form n-aryl-ether from aldoximes, e.g. " \o/ 
 
 (C. 1905, II. 764). But formaldehyde gives methylene-diaryl-hydro- 
 
 xylamines, e.g. CH 2 [N(OH)C 6 H 5 ] 2 . Methylene-diphenyl-hydroxylamine 
 
 is easily converted into the n-phenyl-ether of glyoxime, but under the 
 
 influence of anhydrous SO 4 Cu it passes into diphenyl-oxy-formamidin 
 
 CH /N(OH)C 6 H 5 
 
 \NC 6 H 6 
 
 Acid chlorides acidulate the aryl-hydroxylamines in their nitrogens, 
 e.g. N-Formyl-phenyl-hydroxylamine C 6 H 5 N(CHO)OH, m.p. 71; N- 
 Acetyl-phenyl-hydroxylamine C 6 H 5 N(COCH 3 )OH, m.p. 67; N-Benzol- 
 sulphono-phenyl-hydroxylamine C 6 H 5 N(SO 2 C 6 H 5 )OH (B. 34, 243 ; 35, 
 1883). 
 
 j8-Phenyl-hydroxylamine C ? H 5 NHOH, m.p. 81. Chlorohydrate, 
 white crystalline flakes, precipitated from ether. With metals it also 
 forms salts : C 6 H 5 NHONa from phenyl-hydroxylamine with Na in ether. 
 
 To the above transpositions of ^-phenyl-hydroxylamine we may 
 add the formation of nitroso-phenyl-hydroxylamine with N 2 O 3 , and of 
 phenyl-sulphaminic acid C 6 H 5 NSO 3 H with SO 2 (in etheric solution) ; 
 in aqueous solution, phenyl-hydroxylamine, with SO 2 , gives o-aniline- 
 sulpho-acid (cp. B. 34, 246). For the action of BrCN upon /?-phenyl- 
 hydroxylamine, see B. 37, 1536. 
 
 o-, m-, p-Tolyl-hydroxylamine CH 3 C 6 H 4 NHOH, m.p. 44, 68, 94 ; 
 2, 3-, 2, 4-, 2,5-, 2, 6, and 3, 4-Xylyl-hydroxylamine (CH 8 ) 2 C G H 8 .NHOH, 
 m.p. 74, 64, 91, 98, and 101 ; Mesityl-hydroxylamine (CH 3 ) 3 
 [2, 4, 6]C 6 H 2 NHOH, m.p. 116. 
 
 jS-Chloro- phenyl-hydroxylamine C1C 6 H 4 NHOH, m.p. 88. m- 
 Nitro-phenyl-hydroxylamine NO 2 C 6 H 4 NHOH, m.p. 119, by electro- 
 lytic reduction of m-dinitro-benzol (B. 38, 3078). 3, 5-Dinitro-phenyl- 
 hydroxylamine (NO 2 ) 2 CeH 3 NHOH, m.p. i35-i37, from sym. trinitro- 
 benzol by reduction with H 2 S (C. 1905, II. 1330). 2, 4, 6-Trinitro- 
 phenyl - hydroxylamine (NO 2 ) 3 C 6 H 2 NHOH, m.p. 174, from picryl 
 chloride with hydroxylamine chlorohydrate. On heating with caustic 
 soda it passes into an iso-picric acid, isomeric with picric acid 
 (B. 34, 57). 
 
 Diphenyl-hydroxylamine (C 6 H 5 ) 2 NOH has not up to the present 
 been isolated ; but it probably forms the first product of the splitting 
 of tetraphenyl-hydrazin (q.v.) with concentrated acids (B. 41, 3482). 
 
 o, p-Dinitro-diphenyl-hydroxylamine (NO 2 ) 2 [2, 4]C 6 H 3 N(OH)C 6 H 5 , 
 m.p. 114 with decomposition, orange-coloured needles, from i, 2, 4- 
 bromo-nitro-benzol and j8-phenyl-hydroxylamine. Also formed on 
 treating tetranitro-tetraphenyl-hydrazin with concentrated sulphuric 
 acid. With alkalies, it forms salts, of a brownish-red colour, which, 
 perhaps, belong to the quinoid type : 
 
jS-ALPHYL-NITROSO-HYDROXYLAMINES 79 
 
 In concentrated SO 4 H 2 it dissolves without change, with an intense 
 violet colour (B. 39, 3038). 
 
 p-Nitroso-diphenyl-hydroxylamine NOC 6 H 4 N(OH)C 6 H 5 , shiny bronze 
 scales, melting at I47-I52 with active decomposition, produced by 
 action of concentrated SO 4 H 2 upon nitroso-benzol. The deep-red salts, 
 and the methyl ester derived from them (m.p. 138), may be referred 
 to the quinoid form HON : C 6 H 4 : NOC 6 H 5 . By boiling with dilute 
 SO 4 H 2 or NaOH it is split back into nitroso-benzol (B. 39, 3036). 
 
 4. /3-ALPHYL-NlTROSO-HYDROXYLAMINES. 
 
 j8-Phenyl-nitroso-hydroxylamineC 6 H 5 N(OH).NO or C 6 H 6 NO(:NOH), 
 m -P- 59, produced 
 
 (1) From ice-cold hydrochloric j8-phenyl-hydroxylamine solution 
 with solution of Na nitrite ; 
 
 (2) By action of hydroxylamine and Na alcoholate upon nitro- 
 benzol (C. 1899, II. 371) ; 
 
 (3) From nitroso-acet-anilide, or from potassium-n-diazo-benzol by 
 oxidation with alkaline H peroxide solution (B. 42, 3568, 3582) ; 
 
 (4) By conducting nitric oxide into an etheric solution of phenyl- 
 magnesium bromide (A. 329, 190) ; 
 
 (5) By transposition of nitroso-benzol with the Na salts of nitro- 
 hydroxylaminic acid HON : NO 2 H (Vol. I. 194) or benzol-sulphydr- 
 oxamic acid (C. 1904, I. 24). Ammonium salt, m.p. 164. The 
 slightly soluble iron salt is characteristic. j8-Phenyl-nitroso-hydroxyl- 
 amine is a very unstable body, decomposing spontaneously into 
 nitroso-benzol, diazo-benzol nitrate, and other substances, such as 
 p 2 -dinitro-diphenylamine NH(C 6 H 4 NO 2 ) 2 . By methylating its salts 
 with methyl iodide, or the free substance with diazo-methane, a methyl 
 ether, m.p. 38, is generated, probably referable to the tautomeric form 
 C 6 H 5 NO(: NOH), since reduction with Al amalgam transforms it into 
 diazo-benzol-methyl ester C 6 H 5 N :NOCH 3 (B. 31, 574). 
 
 p-Chloro- and p-Bromo-j8-phenyl-nitroso-hydroxylamme, m.p. 74*5 
 and 87. 
 
 5. AMIDO-DERIVATIVES OR ANILINES. 
 
 The aromatic amido-compounds are derivable from benzene, and 
 the alkyl-benzols, by replacing hydrogen by amido-groups : 
 
 C 6 H 5 .NH 2 C 6 H 4 (NH 2 ) 2 C 6 H 3 (NH 2 ) 3 
 
 Aniline, amido-benzol Diamido-benzol Triamido-benzol. 
 
 On the other hand, we may regard them as derivatives of ammonia, 
 which indicates the existence of primary, secondary, and tertiary 
 amines of the benzene series : 
 
 C 6 H 5 .NH 2 (C 6 H 5 ) 2 NH (C 6 H 5 ) 3 N 
 
 Phenylamine Diphenylamine Triphenylamine 
 
 C 6 H 5 NHCH 3 C 6 H 5 N(CH 3 ) 2 
 
 Phenyl-methylamine Phenyl-dimethylamine. 
 
 If, on the other hand, the hydrogen in the side chains of the benzene 
 homologues is replaced by the amido-group, the true analogues of the 
 
8o ORGANIC CHEMISTRY 
 
 fatty amines are produced, like CgHg.CHg.NHg benzylamine, and 
 these are considered in connection with the corresponding alcohols. 
 
 A. PRIMARY PHENYLAMINES. 
 
 Formation of the primary phenylamines, in which the amido-groups 
 are joined to the benzene nucleus. 
 
 Reduction Reactions. 
 
 i. The amido - derivatives are prepared almost exclusively by 
 reduction of the corresponding nitro-compounds : 
 
 C 6 H 5 N0 2 +6H=C 6 H 5 NH 2 +2H 2 O. 
 
 As intermediate products of the reduction, some conditions yield the 
 j8-phenyl-hydroxylamines and nitroso-benzols. 
 The most important methods of reduction are : 
 
 (a) Action of ammonium sulphide in alcoholic solution (Zinin, 1842) : 
 
 C 6 H 5 .N0 2 + 3 H 2 S=C 6 H 5 .NH 2 + 2 H 2 0+ 3 S. 
 
 In the polynitro-compounds only one nitro-group is easily reduced 
 in this way, and nitro-amido- compounds are produced. 
 
 In the chloro-nitro-benzols the nitro-group is only reduced by 
 Am 2 S if it is not in the neighbourhood of chlorine, or of another nitro- 
 group ; otherwise chlorine, or another nitro-group, is replaced by 
 sulphur or SH (B. 11, 1156, 2056). Generally speaking nitro-groups 
 in ortho position with reference to other substituents are not reducible 
 by Arn 2 S, but the reduction can usually be brought about by stannous 
 chloride (B. 35, 2073 ; C. 1905, II. 1330, but cp. C. 1902, I. 115). 
 On the reduction of nitro-compounds with fixed sulphur alkalies, see 
 C. 1903, I. 746 ; 1907, I. 404. 
 
 (b) Action of zinc and HC1 upon alcoholic solutions of nitro- 
 bodies (A. W. Hofmann) ; action of iron filings and acetic or hydro- 
 chloric acid. Iron and HC1 are used industrially for producing aniline, 
 and o- and p-toluidin. 
 
 (c) Action of tin and HC1 or acetic acid (B. 15, 2105) ; or a solution 
 of stannous chloride in HC1 : 
 
 C 6 H 5 NO 2 +3Sn +6HCl=C 6 H 5 NH 2 +3SnCl 2 -h2H 2 O 
 C 6 H 5 N0 2 +3SnCl 2 +6HCl=C 6 H 5 NH 2 + 3 SnCl 4 +2H 2 0. 
 
 The last reaction may serve for the quantitative determination of 
 the nitro-groups. By adding to the alcoholic solution of a polynitro- 
 compound, an alcoholic hydrochloric solution of the calculated amount 
 of SnCl 2 , one is able to obtain a step-by^step reduction. In the case 
 of o- p-, [2, 4]-dinitro-toluol the [4]-NO 2 group is thus reduced, while 
 with alcoholic Am 2 S the [2]-NO 2 group is reduced (B. 19, 2161 ; cp. 
 B. 35, 2073). In the reduction with Sn and HC1 an addition of graphite 
 favours the reaction (/. pr. Ch. 2, 65, 579). On the speed of reaction 
 with SnCl 2 and HC1, see Z. phys. Ch. 56, i. 
 
 (d) Electrolytic reduction in mineral acid solution converts nitro- 
 compounds into amido-compounds. In concentrated H 2 SO 4 solution 
 the chief product is p-amido-phenol, generated by transposition of the 
 
PRIMARY PHENYLAMINES Si 
 
 /?-phenyl-hydroxylamine first formed. For a summary of literature, 
 see A. 355, 175. 
 
 In many cases the following reducing agents have been used with 
 advantage : 
 
 (e) Titanium trichloride, and HC1, especially for quantitative 
 determinations of the nitro-groups (B. 36, 1554). 
 
 (/) Sodium arseniate (/. pr. Ch. 2, 50, 563). 
 
 (g) Zinc dust in alcoholic, or ammoniacal, solution. 
 
 (h) Ferric sulphate with baryta water (B. 24, 3193), or ammonia 
 (B. 15, 2294), for reducing nitro-bodies soluble in water or alkalies. 
 
 (i) Molecular hydrogen reduces nitro-bodies smoothly to anilines, 
 if the former are conducted at higher temperatures (2OO-4OO) over 
 finely divided metals, such as copper, nickel, etc. (C. 1901, II. 681) ; 
 or if in the presence of colloid metals, especially palladium and platinum 
 at ordinary temperatures, they are treated with hydrogen in alcoholic, 
 or etheric, solution (B. 40, 2209). 
 
 2. By reduction of nitroso-compounds ; see Nitroso-benzol and 
 Nitroso-dimethyl-aniline. 
 
 3. By reduction of hydrazo-compounds, and hydrazins (q.v.). 
 
 Exchange Reactions. 
 
 4. By replacing a halogen atom or nitro-group, an hydroxyl or 
 an alkoxyl group, by an amido-group, the halogen benzols, heated by 
 themselves in ammonia, only yield traces of amido-compounds. But 
 the transformation is readily effected in the presence of small quantities 
 of copper salts (C. 1909, I. 475). The reaction is the readier without 
 a catalyser the more nitro-groups are also introduced, [i, 2]-Chloro- 
 benzol, bromo-nitro-benzol, [i, 2]-dinitro-benzol, [i, 2]-nitro-phenol and 
 its alkyl ethers, [i, 4]-chloro- and bromo-nitro-benzol, [i, 4]-nitro- 
 phenol and its alkyl ethers, when heated with ammonia, give nitro- 
 amido-compounds. The [i, 3]- or w^te-compounds do not react (B. 21, 
 1541 ; A. 174, 276). 
 
 Phenols can be directly converted into primary (and secondary) 
 amines, by heating with ZnCl 2 .NH 3 to 3OO-35o (B. 16, 2812 ; 17, 
 2635 ; 19, 2916 ; 20, 1254). An easier reaction .than that of the 
 phenols is shown by the naphthols : 
 
 C 10 H 7 .OH+NH 3 - '- C 10 H 7 NH 2 -f-H 2 
 Naphthol Naphthylamine. 
 
 5. By heating the halogen derivatives and the alkaline sulphonates 
 with Na amide, NaNH 2 (B. 39, 3006). 
 
 6. A replacement of the carboxyl group of aromatic carboxylic 
 acids by the amine group may be brought about through the inter- 
 mediary of (a) the amides, (b) the azides, of these acids as in the 
 aliphatic carboxylic acids (Hofmann, Curtius). To this may be added 
 (c) Beckmann's transformation of the oximes of aromatic ketones into 
 acidulated aromatic amines (Vol. L), from which the amines are 
 obtained by saponification : 
 
 C G H 5 C(NOH)CH 3 - --> C 6 H 5 NH.COCH 3 > C 6 H 5 NH 2 . 
 
 7. A direct introduction of the amido-group into benzene hydro- 
 VOL. II. a 
 
82 ORGANIC CHEMISTRY 
 
 carbons may be effected by heating the latter with hydroxylamine 
 chlorohydrate, and Al or Fe chloride (B. 34, 1778) : 
 
 C 6 H 6 +NH 2 OH --U C 6 H 5 NH 2 +H 2 0. 
 But this only gives a small amount of anilines. 
 
 ///. Separation Reactions. 
 
 8. By heating amido-carboxylic acids : 
 
 (NH 2 ) 2 C 6 H 3 C0 2 H=C0 2 +C 6 H 4 (NH 2 ) 2 
 Diamido-benzoic acids Phenylene-diamine. 
 
 9. By heating secondary, and tertiary, amines with HC1, and from 
 the quaternary Am salts, by quick heating, without additions : 
 
 , , 
 
 ry Am salts, by quick heating, 
 
 C 6 H 5 .NHCH 3 +HC1=C 6 H 5 .NH 2 
 C 6 H 5 .NHC 2 H 5 .HBr=C 6 H 6 .NH 2 
 
 IV. Nuclear Snthese 
 
 2 +CH 3 C1 
 2 +C 2 H 5 Br. 
 
 IV. Nuclear Syntheses. 
 
 10. On heating aniline with methyl chloride, monomethyl-aniline 
 chloride is first formed, and, at higher temperatures, this splits again 
 into methyl chloride and aniline ; at 340 methyl chloride brings about 
 the replacement of nuclear H in aniline by methyl, thus producing 
 toluidin chlorohydrate. Phenyl-trimethyl-ammonium iodide gives 
 mesidine iodo-hydrate : 
 
 C 6 H 4 NH 2 HC1 /CH 3 
 
 NH.HC1 - > I C 6 H 5 N CH 3 - > C 6 H 2 (CH 3 ) 3 .NH 2 HI 
 
 CH 3 I \CH 3 
 
 Phenyl-methylamine Toluidin Phenyl-trimethyl- Mesidin-iodo-hydrate. 
 
 chlorohydrate chlorohydrate ammonium iodide 
 
 In this way secondary, and tertiary, aromatic bases may be converted 
 into isomeric primary ones. Instead of the halogen salts of the 
 secondary, and tertiary, bases, one can also heat the salts of primary 
 bases with suitable alcohols to 300 (B. 13, 1729) : 
 
 C 6 H 5 NH 2 HC1 + C 4 H 9 OH = C 4 H 9 .C 6 H 4 NH 2 .HC1+H 2 O 
 Aniline chlorohydrate Isobutyl-alk. Amido-tertiary-butyl-benzol. 
 
 Or free bases are heated with paraffin alcohols, and zinc chloride, to 
 250 (B. 16, 105). 
 
 11. The oximes of many hydro-aromatic ketones, such as those 
 of methyl- and dimethyl-cyclo-hexenone, trimethyl-cyclo-hexenone, or 
 iso-aceto-phenone, yield primary anilines on heating with HC1, with 
 atomic displacement (A. 322, 379). 
 
 PROPERTIES AND TRANSFORMATIONS OF PHENYLAMINES. 
 
 The primary amines are colourless compounds of a peculiar, and 
 not unpleasant, odour, and can be distilled, without decomposition, 
 at ordinary pressures. As regards formation of salts they resemble 
 alkylamines (Vol. I.), but they are much feebler bases than the primary 
 alkylamines, have no alkaline reaction, and are but slightly soluble 
 in water, though volatile with water vapour. 
 
PROPERTIES OF PHENYLAMINES 83 
 
 The basic character of primary phenylamines is further weakened 
 by the entry of negative groups ; the salts of the di-substituted anilines, 
 such as C 6 H 3 C1 2 .NH 2 and C 6 H 3 (NO 2 )2.NH 2 , are decomposed by water 
 alone, and cannot survive. The compounds resemble the carboxylic 
 amides in chemical behaviour, just as the corresponding oxy-com- 
 pounds, or phenols, have the character of acids. 
 
 Hydrogen reduces the amido-compounds to the corresponding 
 hexahydro-anilines, on leading their vapours over finely divided 
 nickel, at 190, or on heating at high pressure in presence of nickel. 
 The resulting bodies again show, as cyclo-alkylamines, the strongly 
 basic character of the aliphatic amines. 
 
 Aniline will be studied in detail as the type of primary phenyl- 
 amines. But first the following general reactions of the amido-group 
 will be specified : 
 
 1. Alkali metals dissolve on heating, with liberation of H. From 
 aniline we obtain potassium anilide C 6 H 5 NHK, and dipotassium 
 anilide C 6 H 5 NK 2 . 
 
 2. Halogen alky Is combine with the anilines to secondary, tertiary, 
 and finally to quaternary ammonium compounds (Vol. I.). 
 
 3. One molecule of an aldehyde combines with one or two mole- 
 cules of a primary amine, with liberation of water (B. 25, 2020). With 
 furfurol all primary anilines give intensely red compounds. 
 
 4. Of extreme importance, for the development of aromatic 
 chemistry, has been the behaviour of free primary anilines, and their 
 salts, with nitrous acid. Diazo-amido- and diazo-compounds are 
 produced, the latter forming the links in the conversion of nitro- and 
 amido-compounds, into the most diverse substitution products. 
 
 5. With thionyl chloride the primary anilines behave like the 
 primary aliphatic amines (Vol. I.) ; thionyl-anilines are thus produced. 
 
 6. A hydrogen atom of the amido-group is very easily replaced 
 by acid residues, acid anilides being thus formed, which correspond 
 to the acid amides (Vol. I.). The easily crystallised acetic compounds 
 are formed with special frequency. 
 
 7. Like the primary aliphatic amines (Vol. I.), the primary anilines 
 give, with chloroform, and alkaline hydroxides, carbyl-amines. 
 
 8. With CS 2 the primary anilines combine to di-aryl-sulpho-uric 
 compounds, with liberation of SH 2 , while the primary aliphatic amines 
 yield ammonium alkyl-dithio-carbaminates (Vol. I.). 
 
 9. Of significance for the development of quinolin chemistry 
 has been the synthesis of quinolin (q.v.), and other bases containing 
 quinolin nuclei, on heating aniline, and other primary aromatic bases, 
 with glycerin, sulphuric acid, and nitro-benzol. Quinolin derivatives 
 are also produced by condensation into fatty aldehydes by HC1 or 
 H 2 SO 4 . 
 
 10. Primary aromatic bases, heated with a-halogen-keto-com- 
 pounds, yield indols (q.v.), sometimes with dihydro-pyrazin derivatives 
 fe.). 
 
 ANILINE, phenylamine [aminophene] [amino-benzene) C 6 H 6 NH 2 , 
 m.p. 8, b.p. 184, D 1-0361, is an oil of a feebly aromatic odour, 
 soluble at 12-5, in 31 parts water (B. 10, 709). 
 
 Historical. Aniline was first discovered in 1826, by Unverdorben, 
 during distillation of indigo, and was called " crystalline " on account 
 
84 ORGANIC CHEMISTRY 
 
 of the crystallising power of its salts. In 1834 Runge found it in coal- 
 tar, and called it " cyanol," on account of its blue colour in bleaching- 
 powder solution. In 1841 Fritzsche prepared a base, by distillation of 
 indigo with KHO, and called it " aniline " from the name of the indigo 
 plant, Indigo/era anil. In the same year Zinin prepared " benzi- 
 dame " by reducing nitro-benzol with Am 2 S. The identity of the 
 four bases was proved by A. W. Hofmann in 1843 (A. 47, 37). 
 
 Industrially, aniline is obtained on a large scale by reduction of 
 nitro-benzol with iron, and about one-fortieth of the HC1 required 
 according to the equation : 
 
 C 6 H 5 N0 2 +2Fe+6HCl=C 6 H 5 NH 2 +Fe 2 Cl 6 +2H 2 0. 
 
 Probably only FeCl 2 is formed at first, and its presence brings about 
 a reduction of the nitro-benzol by iron and water, the ferrous chloride 
 serving as a carrier. The finely divided moist metal is the immediate 
 reducing agent (B. 27, 1436, 1815). 
 
 C 6 H 5 NO 2 +3Fe+6HCl=C 6 H 5 NH 2 +3FeCl 2 +2H 2 O 
 C 6 H 5 N0 2 +2Fe+ 4 H 2 0=C 6 H 5 NH 2 +Fe 2 OH) 6 . 
 
 The other means which can be used for reducing nitro-benzol to 
 aniline have been explained above, where aniline has been usually 
 chosen as the primary phenylamine. The same applies to the other 
 reactions. Aniline is almost as much used in reactions as ammonia, 
 and is the generator in numerous aromatic compounds. In spite of 
 its feeble basicity, it precipitates zinc, aluminium, and ferrous salts, 
 and displaces ammonia from its salts on account of being less volatile. 
 
 Aniline is a poison. It is a solvent for many bodies, e.g. indigo. 
 
 Aniline is very sensitive to oxidisers. It gradually colours brown 
 in air, and becomes resinous. Bleaching-powder solution colours 
 aniline purple- violet (B. 27, 3263). With sulphuric acid, and a few 
 drops of potassium bichromate, aniline colours red, and, afterwards, an 
 intense blue. On oxidising aniline with hot chloride of lime, or with 
 cold MnO 4 K, it can be reconverted into nitro-benzol, through a series 
 of intermediate products (B. 26, 496 ; 31, 1522). With chromic 
 acid it yields quinone (q.v.) ; with chlorides, in the presence of certain 
 metallic salts, it gives aniline black (q.v) . 
 
 With nitroso-benzol aniline combines to azo-benzol, and with 
 caustic potash and nitro-benzol it gives azo-benzol, and phenazin 
 oxide (B. 34, 2442). 
 
 Aniline is used in preparing numerous dyes and medicines, such 
 as aniline black, fuchsin, etc., and antifebrin, antipyrin, etc. 
 
 Aniline salts. Chlorohydrate is obtained quite pure and dry by con- 
 ducting HC1 through an etheric aniline solution, m.p. 198, b.p. 245 
 (B. 31, 1698) ; industrially it is called " aniline salt." In water it 
 rapidly dissolves. Platinum chloride double salt, yellow needles, from 
 alcohol. Stannous and stannic chloride double salt SnCl 2 .2C 6 H 5 . 
 NH 2 .HC1 + 2H 2 O and SnCl 4 .2C 6 H 5 .NH 2 .HCl -f 2H 2 O. Sulphate 
 (C6H 6 NH 2 ) 2 SO 4 H 2 . Thiosulphate S 2 O 3 H 2 (C G H 5 NH 2 ) 2 : only primary 
 anilines form normal thiosulphates, not secondary or tertiary ones 
 (C. 1902, I. 303). Nitrate forms rhombic plates ; oxalate, rhombic 
 prisms. Not only the chlorohydrate but also free aniline forms double 
 
PROPERTIES OF PHENYLAMINES 85 
 
 salts with some salts. It also combines additively with trinitro- 
 benzol. 
 
 Potassium anilide : C 6 H 5 NHK and C 6 H 5 NK 2 are unknown in a 
 pure condition. The formation of di- and trimethylamine, by action 
 of bromo-benzol upon the reaction product of K upon aniline, proves 
 that the hydrogen of the amido-group is replaced by K. Na does 
 not act upon aniline below 200. Small quantities of Cu, CuO, etc., 
 facilitate the formation of the Na salt (C. 1909, II. 1512). Cp. also 
 acetanilide, and monomethyl-aniline. 
 
 Magnesium haloid compounds of aniline (like C 6 H 5 NHMgI) are 
 obtained in the shape of crystalline precipitates by the action of 
 aniline upon an etheric solution of alkyl-magnesium haloids (C. 1903, 
 I. 1024) : 
 
 C 6 H 5 NH 2 +CH 3 MgI=C 6 H 5 NH.MgI+CH 4 . 
 
 They strongly absorb CO 2 , forming salts of carbaminic acid (B. 37, 
 3978) ; with acid esters they give the corresponding acid anilides 
 (C. 1904, I. 201 ; 1906, I. 1000). 
 
 Amido-methyl-benzols. Some representatives of this group are 
 of great importance in the dye industry, especially o- and p-toluidin. 
 Most of the bases are liquid at ordinary temperatures, but easily 
 yield acetic compounds, on boiling with glacial acetic acid, or treating 
 with acetyl chloride or acetic anhydride. These substituted aceta- 
 mides are easily crystallising bodies, of definite melting-point, very 
 suitable for characterisation of the bases, from which they are easily 
 obtained. The melting-point of the acetic compound is therefore, in 
 what follows, added to the m.p. or b.p. of the base. Amido-methyl- 
 benzols are obtained by the reduction of the corresponding nitro- 
 compounds, and by heating chlorides of the bases, methylated as 
 regards the nitrogen, like dimethyl-aniline C 6 H 5 N(CH 3 ) 2 , under pressure, 
 at high temperature. 
 
 Toluidin CH 3 .C 6 H 4 NH 2 . The three toluidins are isomeric with 
 benzyl-amine C 6 H 5 CH 2 NH 2 (treated in connection with benzyl- 
 alcohol) and with methyl-aniline C 6 H 5 NHCH 3 . They are obtained by 
 reduction of the three nitro-toluols. m-Toluidin is also prepared by 
 reduction of m-nitro-benzol chloride, a transformation product of 
 m-nitro-benzaldehyde (B. 15, 2009 ; 18, 3398). p-Toluidin was 
 discovered in 1845 by A. W. Hofmann and Muspratt (A. 54, i). 
 
 o-Toluidin, liquid . b.p. 197 ; Acet-o-tolnide, m.p. 110, b.p. 296 
 m-Toluidin, ,, . 199 ; Acet-m-toluide, ,, 65, ,, 303 
 p-Toluidin, m.p. 45 198 ; Acet-p-toluide, ,, 153, 307 
 
 p-Toluidin unites with one molecule of water to a monohydrate 
 CH3C 6 H 4 .NH 2 .H 2 O, m.p. 41-5, which may be used for isolating, and 
 purifying, the base (C. 1908, I. 2092). 
 
 The chlorohydrates of o-, m-, and p-toluidin melt at 215, 228, and 
 243 respectively, and boil without decomposition at 242, 250, and 
 257 respectively (B. 31, 1698). 
 
 Separation of o- and p-toluidin. Nitrogenation of toluol forms 
 o- and p-nitro-toluol, from which the industrially important toluidins are 
 obtained. The o-toluidin is separated from the p-toluidin by treat- 
 ing the mixed bases with an amount of sulphuric acid insufficient for 
 
86 
 
 ORGANIC CHEMISTRY 
 
 complete neutralisation, and distilling. The stronger p-base remains 
 behind, as a sulphate. Or we can utilise the greater solubility of the 
 o-toluidin oxalate (/. pr. Ch. 2, 14, 449). Aniline, o- and p-toluidin 
 may also be separated by the different behaviour of their chloro- 
 hydrates towards mono-sodium phosphate (B. 19, 1718, 2728 ; cp. 
 B. 29, R. 434). 
 
 In the aniline dye industry there is a distinction between : 
 
 Aniline oil for blue : pure aniline. 
 
 Aniline oil for red : molecular quantities of aniline, o- and 
 
 p-toluidin. 
 Aniline oil for safranin: aniline and o-toluidin, from the 
 
 distillate of the fuchsin mixture. 
 
 The free toluidins are easily transformed, by oxidation, into azo- 
 compounds (B. 26, 2772). If the amido-group is protected from oxi- 
 dation, by introducing an acid radicle, e.g. the acetyl group, the methyl 
 group may be oxidised to a carboxyl group with potassium per- 
 manganate, and o-aceto-toluide may thus be converted into o-acet- 
 amido-benzoic acid (B. 14, 263). In the chlorination, bromination, or 
 nitrogenation of the aceto-toluides, the negative substituent is mostly 
 placed in the o-position with respect to the acet-amido group (see 
 Rules of Substitution). 
 
 o-Toluidin, like aniline, is coloured violet by chloride of lime solu- 
 tion and HC1, but p-toluidin is not. Iron chloride separates, from the 
 hydrochloric o-toluidin solution, a blue body, known as toluidin blue. 
 
 Xylidins (CH 3 ) 2 C 6 H 3 NH 2 . All the six possible isomers are known : 
 
 v-o-Xylidin, liquid, b.p. 223 
 as-o-Xylidin, m.p. 49, ,, 226 
 v-m-Xylidin, liquid ,, 216 
 as-m-Xylidin ,, ,, 212 
 
 s-m-Xylidin 220 
 
 p-Xylidin, m.p. 15 213 
 
 corresponding Acetoxylide,m 
 
 P- 134 
 , 99 
 , 170 
 
 , 120 
 , 144 
 
 180 
 
 For melting- and boiling-points of the chlorohydrates, see B. 31, 
 1699. 
 
 The xylidin used industrially for making azo-dyes, and obtained 
 from dimethyl-aniline, is chiefly m-xylidin and p-xylidin (B. 18, 2664, 
 2919). Concerning the separation of isomeric xylidins from each other, 
 see C. 1899, II. 1113. 
 
 Amido - polymethyl - benzols (CH 3 ) 3 C 6 H 2 NH 2 . The product in- 
 dustrially obtained by heating xylidin chloride, with methyl alcohol, 
 to 250, under pressure, consists essentially of s-pseudo-cumidin and 
 mesidin, and is used for preparing red azo-dyes (B. 15, ion, 2895). 
 
 s-Pseudo-cumidin [5NH 2 , 1,2,4], m -P- 68; b.p. 235; acetic com- 
 pound, m.p. 164 (B. 18, 92, 2661). 
 
 Mesidin [2NH 2 , 1,3,5], liquid, b.p. 230; acetic compound, m.p. 
 216 (B. 18, 2229 ; 24, 3546). 
 
 Duridin [3NH 2 , i, 2, 4, 5], m.p. 75, b.p. 26i-262 ; acetic com- 
 pound, m.p. 207 (B. 42, 4160). 
 
 Isoduridin [4NH 2 , i, 2, 3, 5], m.p. 23, b.p. 255; acetic compound, 
 m.p. 215 (B. 18, 1149). 
 
SECONDARY AND TERTIARY PHENYLAMINES 87 
 
 Prehnidin [5NH 2 , i, 2, 3, 4], m.p. 64, b.p. 260 ; acetic compound, 
 m.p. 170 (B. 21, 644, 905). 
 
 Amido-pentamethyl-benzol, m.p. 151, b.p. 277 ; acetic compound, 
 m.p. 213 (B. 18, 825). 
 
 Aniline homologues with larger alcohol radicles are obtained 
 not only from the corresponding nitro-compounds by reduction, but 
 also from aniline itself by a nuclear synthesis, when aniline is heated 
 to 250-28o, with aliphatic alcohols, and zinc chloride. The alkyl 
 takes up the p-position with respect to the amido-group. If iso-butyl 
 and iso-amyl alcohol are used, p-terti-butyl- and p-terti-amyl aniline are 
 produced, water being probably first given off, with formation of 
 iso-butylene, and ^3-iso-amylene, respectively, which, under the influence 
 of the condensing agent, attach themselves to the p-carbon atom of 
 the aniline. 
 
 p-Amido-ethyl-benzol C 2 H 5 C 6 H 4 NH 2 , m.p. -5, b.p. 216 (B. 22, 
 1847). 
 
 p-Amido-propyl-benzol, b.p. 225 ; acetic compound, m.p. 87 (B. 
 17, 1221). 
 
 p-Amido-iso-propyl-benzol, b.p. 225 ; acetic compound, m.p. 102 
 (B. 21, 1159). 
 
 p-Amido-tert.-butyl-benzol, m.p. 17, b.p. 240 ; acetic compound, 
 m.p. 172 (B. 24, 2974). 
 
 p-Amido-oetyl-benzol, m.p. 19, b.p. 310 ; acetic compound, m.p. 
 93 (B. 18, 135). 
 
 B. SECONDARY AND TERTIARY PHENYLAMINES AND PHENYL- 
 AMMONIUM BASES. 
 
 Phenyl-alkylamine. Modes of formation : (i) The alkyl products 
 of aniline, and its homologues, are formed, like the aliphatic amines 
 (Vol. L), by the action of alkyl bromides and alkyl iodides upon primary 
 bases, mostly even at ordinary temperatures. They can also be ob- 
 tained by heating aniline chlorohydrate, or, better, aniline bromo- 
 hydrate (B. 19, 1939), with alcohols, to 250, alkyl chlorides or bro- 
 mides being first formed, which then act upon the aniline. 
 
 (2) The above method yields the haloid salts of mono- and di- 
 alkyl-aniline together. To obtain mono-alkyl-anilines separately, a 
 start is made from the aceto-compounds of the primary bases. These 
 are dissolved in toluol or xylol, and the calculated quantity of sodium 
 is introduced into the solution. Hydrogen is developed, and white 
 solid Na acetanilide is formed, and transformed smoothly with iodo- 
 alkylene. By saponification of the alkyl acetanilide, the alkyl-aniline 
 is obtained : 
 
 Separation of the Primary, Secondary, and Tertiary Bases. From 
 the acid solution of a mixture, the secondary bases are precipitated, by 
 sodium nitrite, as oily nitrosamines, while the primary ones become 
 diazonium chlorides soluble in water, and the tertiary amines become 
 chlorohydrates (also soluble) of p-nitroso-dialkyl-anilines. From the 
 precipitated nitrosamines the secondary bases can be recovered, by 
 means of tin and HC1. Hydro-ferro-cyanic salts (A. 190, 184), and 
 
88 ORGANIC CHEMISTRY 
 
 meta-phosphates, may also be used for this separation (B. 10, 795 ; 
 22, 605 ; 26, 1020). 
 
 Phenyl-alkyl-ammonium Bases. The tertiary phenyl-alkylamines, 
 like C 6 H 5 N(C 2 H 5 ) 2 , may be combined with alkyl haloids to Am com- 
 pounds, from which Am hydroxides are generated by action of moist 
 silver oxide or lime : 
 
 C 6 H 5 N(C 2 H 5 ) 3 I gives C 6 H 5 N(C 2 H 5 ) 3 OH. 
 
 In homologous anilines, containing the substituents in ortho-position 
 with respect to the amine group, the formation of quaternary Am 
 bases is partly difficult, and partly impracticable (B. 33, 345 ; cp. 34, 
 1129) ; this accords with a number of other impediments to reaction 
 set by ortho-substituents. A number of phenyl-alkyl-ammonium 
 bases with three different alkyl radicles, e.g. phenyl-methyl-alkyl-ethyl- 
 ammonium hydroxide, may be decomposed by fractional crystallisa- 
 tion, of their bromo-camphoro-sulphonic salts, into optically active 
 nitrogen compounds. Their solutions, especially in solvents con- 
 taining hydroxyl, show a strong tendency to auto-racemisation, thus 
 tending to a gradual loss of optical activity. 
 
 Di-alkyl-aniline Oxides. Prepared from the di-alkyl-anilines, by 
 oxidation with hydrogen peroxide, or sulpho-mono-per-acid (B. 35, 
 1082). They correspond to trimethyl-amino-oxide (CH 3 ) 3 NO (Vol. I.), 
 and the alkyl-piperidin oxides (q.v.). Methyl groups, in the o-position, 
 retard the formation of dialkyl-aniline oxides (B. 39, 4285). With 
 acids they form additive salts, e.g. Dimethyl-phenyl-oxy-ammonium- 
 
 chlorohydrate C G H 5 N(CH 3 ) 2 / H . They easily part with their oxygen, 
 
 \v_/l 
 
 and, therefore, act as oxidisers. On heating dimethyl-aniline oxide, 
 or its chlorohydrate, it breaks up into dimethyl-aniline and oxygen. 
 But the latter acts as an oxidiser on the former, so that a number of 
 other decomposition products are formed. On heating dimethyl- 
 aniline oxide with concentrated sulphuric acid, o- and p-dimethyl- 
 amido-phenol are generally formed (B. 34, 12). With nitrous and 
 sulphurous acids, addition products are first formed, which, however, 
 are immediately transposed into nuclear substitution substances : 
 nitro-dimethyl-aniline and dimethyl-aniline-sulpho-acid (B. 32, 342, 
 1882). 
 
 Methyl-ethyl-aniline oxide C 6 H 5 (CH 3 )(C 2 H,j)NO has been split 
 up, by means of bromo-camphoro-sulpho-acid, into a dextro-rotatory 
 and a lasvo-rotatory base. This is the first case of a compound of 
 5-valent nitrogen occurring in optically active forms, in which not all 
 the five valencies are saturated by different radicles. 
 
 Properties and Transformations. The most important compounds 
 of this class are the methyl- and ethyl-anilines. Freshly distilled, 
 they are colourless, highly refractive liquids, which gradually turn 
 brown in the light. They smell somewhat like aniline, but less pleasant. 
 
 The secondary phenyl-alkylamines recall in their behaviour the 
 dialkylamines (Vol. I.), (i) They form salts, and combine with the 
 halogen alkyls to form haloid salts of the tertiary amines. (2) By 
 acid chlorides, and acid anhydrides, the imide hydrogen is made to 
 give way to acid radicles. (3) With nitrous acid they yield nitros- 
 amines (Vol. I.). 
 
SECONDARY AND TERTIARY PHENYLAMINES 89 
 
 The tertiary phenyl-dialkylamines containing an aromatic H atom 
 in para-position to the dialkyl-amido-group, show a remarkable mobility 
 of this H atom, which enables it to produce a variety of reactions im- 
 possible, or difficult, in the case of the primary and secondary anilines. 
 The greatest theoretical and technical importance is attached to the 
 behaviour of phenyl-dialkylamines towards nitrous acid. The latter 
 converts the phenyl-dialkylamines into p-nitroso-compounds. 
 
 The primary, secondary, and tertiary aromatic amines differ in 
 their behaviour towards nitrous acid in the following particulars : 
 
 (1) Primary phenylamines gives diazo-compounds, and diazo- 
 amido-compounds. 
 
 (2) Secondary phenyl-alkylamines give nitrosamines. 
 
 (3) Tertiary phenyl-dialkylamines give />-m>oso-compounds. 
 Some other reactions of phenyl-dialkylamine are mentioned in 
 
 connection with dimethyl-aniline. 
 
 The methyl- and ethyl-anilines have the following boiling-points 
 and densities : 
 
 Monomethyl-aniline, liquid, b.p. 192, D. 0-976 (15) 
 Dimethyl-aniline, m.p. 0-5, ,, 192, ,, 0-9575 (2o-24) 
 Ethyl-aniline, liquid, ,, 206, ,, 0-954 (18) 
 
 Diethyl-aniline, 213-5, 0-939 (18). 
 
 The methylated anilines are used in industry for the production of 
 aniline dyes, and are obtained by heating aniline chlorohydrate and 
 methyl-alcohol to 220, or by leading methyl chloride into boiling 
 aniline. 
 
 Methyl-aniline C 6 H 5 NHCH 3 , by reduction of phenyl-carbylamine 
 and formaldehyde- aniline. Chlorohydrate, m.p. 122, obtained from 
 the etheric solution of the base with dry HC1 (B. 30, 3134 ; C. 1898, 
 II. 479). Not coloured by chloride of lime. On heating to 330 it 
 passes into p-toluidin. For methyl-phenyl-nitrosamine and methyl- 
 acetanilide, see below. 
 
 By oxidation with hydrogen peroxide or monopersulphonic acid the 
 alkyl groups are split off, from methyl- and ethyl-aniline, and we obtain 
 jS-phenyl-hydroxylamine, nitroso- and nitro-benzol, azoxy- and azo- 
 benzol (B. 35, 703). 
 
 With formaldehyde and HC1, methyl- and ethyl-aniline form 
 C 6 H 5 N(CH 3 )CH 2 C1 and C 6 H 5 N(C 2 H 5 )CH 2 C1, which, by reduction, can 
 be converted into dimethyl- and methyl-ethyl-aniline (C. 1902, II. 340 ; 
 1905, I. 227). 
 
 Dimethyl-aniline C 6 H 5 N(CH 3 ) 2 is also formed on heating bromo- 
 or iodo-benzol with dimethylamine to 25o-26o (C. 1898, II. 478). 
 With dry HC1 it yields a mono- and a dichlorohydrate, C 6 H 5 N(CH 3 ) 2 . 
 HC1 and C 6 H5N(CH 3 ) 2 .2HC1, crystalline bodies deliquescing in moist 
 air, which easily give off HC1 (B. 30, 3134). lodo-hydrate, m.p. 112, 
 cp. C. 1898, II. 479. Not coloured by hypochlorite. With methyl 
 iodide it combines to form trimethyl-phenylium iodide C 6 H 5 N(CH 3 ) 3 I. 
 Treated with nitrous acid it passes into p-nitroso-dimethyl-aniline, and, 
 with nitric acid, into p-nitro-dimethyl-aniline. With acetyl and 
 benzoyl bromides it gives acetyl- and benzoyl-monomethyl-aniline, 
 besides trimethyl-phenyl-ammonium bromide (B. 19, 1947). By 
 hydrogen peroxide and monopersulphonic acid it is oxidised to : 
 
go ORGANIC CHEMISTRY 
 
 Dimethyl-aniline oxide C 6 H 5 N(CH 3 ) 2 O, m.p. 153. Picrate, m.p. 
 135 ; chlorohydrate, m.p. 125. 
 
 Dimethyl-aniline has been introduced into a number of condensa- 
 tion reactions. With chloral it combines to p-amido-mandelic acid 
 (CH 3 ) 2 N[4]C 6 H 4 [i]CH(OH).CCl3. With phosgene it passes into 
 tetramethyl-p-diamido-benzo-phenone [(CH 3 ) 2 N[4]C 6 H 4 [i]] 2 CO ; with 
 formic ester and zinc chloride, into hexamethyl-p-leukaniline CH 
 [C 6 H 4 N(CH 3 ) 2 ] 3 ; and with benzo-trichloride, into malachite green (q.v.). 
 
 The homologous mono- and dialkyl- anilines behave similarly. We 
 may mention Methyl-ethyl-aniline C 6 H 5 N(CH 3 )(C 2 H 5 ), b.p. 201. Its 
 compound with CH 3 I is identical with dimethyl-aniline-ethyl iodide ; 
 from which, and others, theoretical conclusions can be drawn with 
 regard to the equivalence of the five nitrogen affinities (cp. B. 33, 1003). 
 By heating with KHO, the higher alkyl is split off from these Am 
 iodides. 
 
 Methyl-ethyl-anffine oxide C 6 H 5 (CH 3 )(C 2 H 5 )NO, from methyl-ethyl- 
 aniline and hydrogen peroxide ; colourless and very hygroscopic 
 prisms. Chlorohydrate, m.p. 124; picrate, m.p. 148. On the split- 
 ting of the base into optically active components, see above. 
 
 Alkylene-mono- and dianilines are obtained from dibromo-paraffins 
 with anilines ; [i, 4]-dibromides react with formation of cyclic alkylene 
 imides, or pyrrolidins (Vol. I.), unless a substituent is in the ortho- 
 position to the amido group (" steric hindrance," see B. 32, 848, 2251). 
 
 Ethylene-monophenyl-diamine NH 2 .CH 2 .CH 2 .NHC 6 H 5 , b.p. 263, 
 from phthalimide of potassium (B. 24, 2191). Ethylene-diphenyl- 
 diamine C 6 H 5 NH.CH 2 .CH 2 .NHC 6 H 5 , m.p. 65. Trimethylene-diphenyl- 
 diamine C 6 H 5 NH[CH 2 ] 3 NHC 6 H 5 , b.p. iq 28o-285, besides Trimethylene- 
 phenylimine, from trimethylene bromide and aniline. 1, 4-Pentylene- 
 di-o-toluidin CH 3 C 6 H 4 NH.CH 2 .CH 2 CH 2 CH(CH 3 )NHC 6 H 4 CH 3 , b.p. 23 
 I 9 i-i93. 
 
 Further cyclic alkylene-dianilines like [CH 2 ] 2 / N ( c ' H s)\CH 2 , m.p. 
 
 \N(C 6 H 5 )/ 
 
 124, and [CH 2 ] 3 /^^^)\cH 2 , m.p. 87, Diphenyl-hydro-glyoxalins 
 
 \JN (U 6 tL 5 ) / 
 
 and -pyrimidins, have been obtained from alkylene-dianilines with 
 aldehydes (B. 31, 328 ; 32, 2256). 
 
 Alkylidene-dianilines are easily obtained, in cold aqueous solutions, 
 from fatty aldehydes (i mol.) and anilines (2 mols.). They are decom- 
 posed by mineral acids. The methylene-dianilines, heated with 
 concentrated HC1, or the corresponding aniline chlorohydrates, are 
 transformed into diamido-diphenyl-methanes (B. 41, 2145) : 
 
 C 6 H 5 NH.CH 2 .NHC 6 H 5 -> [C 6 H 3 NH.CH 2 .C 6 H 4 NH 2 ] -> NH 2 C 6 H 4 .CH 2 .C C H 4 NH 2 . 
 
 The simpler alkylene-dianilines easily pass into the alkylidene-mono- 
 anilines, or their transformation products. 
 
 Methylene-diphenyl-diamine CH 2 (NHC 6 H 5 ) 2 , m.p. 65, b.p. 12 160, 
 oxidised with monopersulphonic acid, gives several fission products, 
 and also diphenyl-oxy-form-amidin (B. 35, 714). Methylene-o 2 - and 
 p 2 -ditolyl-diamine, m.p. 52 and 89. Ethylidene-diphenyl-diamine 
 CH 3 CH(NHC 6 H 5 ) 2 , m.p. 51. Trichlor - ethylidene - diphenyl - diamine 
 CC1 3 CH(NHC 6 H 5 ) 2 , m.p. 107. 
 
 Alkylidene-monoanilines are formed by an energetic reaction, by 
 
SECONDARY AND TERTIARY PHENYLAMINES 91 
 
 combination of equimolecular amounts of fatty aldehydes and anilines, 
 with elimination of water ; the simple bodies are mostly unstable oils, 
 which at once either polymerise, like formaldehyde-aniline, or condense, 
 like aldol. 
 
 With sulphurous acid and sodium disulphite, the alkylidene-anilines 
 act like the aldehydes, but the reaction is more complicated in the 
 higher homologues of the aldehyde derivatives ; from ethylidene-aniline 
 
 we obtain CH 3 CH/^^ H5 ' the Na salt of which is also formed from 
 
 \SO 3 H 
 
 acetaldehyde sodium bisulphite, with aniline. The simple, as well as 
 the polymeric, alkylidene-anilines easily add hydrocyanic acid, with 
 formation of the nitrites of a-anilido-carboxylic acids, also obtained 
 by direct transformation of aniline salts, with aldehydes, and CNK 
 (B. 37, 4073 ; 39, 986, 2796). The aldoloid condensation products, 
 on the other hand, do not add HCN ; they behave like di-acid, di- 
 secondary bases ; they do add bromine, and must therefore be regarded 
 as probably dianiline derivatives of the olefin-glycols, e.g. CH 3 CH 
 (NHC 6 H 5 )CH : CH(NHC 6 H 5 ). These bodies are easily condensed with 
 further elimination of aniline to quinolin derivatives (B. 25, 2020 ; 
 A. 316, 89 ; 318, 58 ; C. 1902, I. 911). 
 
 Anhydro-formaldehyde-aniline (CH 2 NC6H 5 ) 3 , m.p. 140, obtained 
 by mixing formaldehyde solution with aniline in the cold. May be 
 reduced to methyl-aniline. Gives with HCN anilido-aceto-nitrile. With 
 aromatic amines the anhydro-formaldehyde anilines condense, in the 
 presence of chlorohydrates, to amido-benzyl-anilines (C. 1900, 1. 496) : 
 
 C 6 H 5 N : CH 2 +C 6 H 5 NH 2 > C 6 H 5 NH.CH 2 C 6 H 4 NH 2 . 
 
 Ethylidene-aniline CH 3 CH : NC 6 H 5 , an oil, easily adds hydrocyanic 
 acid to a-anilido-propio-nitrile, and easily condenses to two stereo- 
 isomeric modifications of j8-anilido-butylidene-aniline CH 3 CH(NHC 6 H 5 ). 
 CH : CHNHC 6 H 5 , m.p. 126 and 85, the latter being easily transformed 
 into the former. On heating with HC1 or acetic acid both give 
 quinaldin. With HNO 2 they yield two dinitroso-compounds of m.p. 161 
 and 120. Aldonaniline CH 3 CH(OH)CH 2 CH : NC 6 H 5 , from aldol and 
 aniline, is a reddish, easily decomposed oil ; by treatment with Am 2 S 
 it is transformed into thio-aldo-aniline CH 3 .CH(OH)CH 2 CH NC 6 H 5 , 
 
 \S/ 
 
 m.p. 92 (B. 29, 59). For higher homologues, alkylidene-anilines, 
 and aldol-anilines, see B. 33, 3460 ; 34, 509 ; C. 1901, II. 582, etc. 
 
 C. POLY-PHENYLAMINES. 
 
 The modes of formation, and the behaviour, of these compounds 
 are to be illustrated by di- and triphenylamine. 
 
 Diphenylamine NH(C 6 H 5 ) 2 , m.p. 54, b.p. 310. (i) This com- 
 pound, of importance in the aniline-dye industry, was first obtained 
 by A. W. Hofmann, by heating aniline blue, rosaniline, and similar 
 dyes (A. 132, 160). (2) By heating aniline with aniline chlorohydrate 
 to 140, a large-scale industrial process : 
 
 C 6 H 5 NH 2 HCl+C 6 H 5 NH 2 =NH(C 6 H 5 ) 2 -hNH 4 Cl. 
 
 In a similar manner ditolyl-amines have been prepared (C. 1903, 1. 85). 
 (3) By heating aniline with bromo-benzol and copper powder, or 
 
92 ORGANIC CHEMISTRY 
 
 cuprous iodide, good quantities of diphenylamine are obtained. It is 
 well to start from acetanilide, and obtain, first, the acetyl compound, 
 from which the free base is easily separated. (4) By heating aryl- 
 anthranilic acids, with liberation of CO 2 (A. 355, 312). The last two 
 methods are very suitable for preparing asymmetrical and substituted 
 diphenylamines (B. 40, 4541). 
 
 Diphenylamine is a crystalline body, of pleasant odour. In water 
 it is nearly insoluble, but easily soluble in alcohol and ether. 
 
 It is but a weak base, the salts of which are dissolved by water. 
 The imide hydrogen may also be replaced by metals : potassium- 
 diphenyl-amine (CeH 5 ) 2 NK (C. 1898, II. 1252). 
 
 Oxidation of diphenylamine with potassium permanganate, or lead 
 peroxide, in acetone, or benzol solution, gives tetmphenyl-hydrazin 
 (B. 39, 1500). In alkaline solution it is oxidised by potassium per- 
 manganate to diphenyl-p-azophenylene, or quinone-dianile C 6 H 5 N 
 = [i]C 6 H 4 [4]=NC 6 H 5 (B. 20, R. 719). Chlorine and bromine change 
 diphenylamine into tetra- or hexahalogen substitution products ; 
 HNO 3 into the hexanitro-products. H 2 SO 4 dissolves diphenylamine, 
 and the solution colours blue with traces of HNO 3 (test for the latter). 
 
 / C^ TT \ 
 
 Heating with sulphur gives thio-diphenylamine, NH<(^ C 6 ] yS (q.v.), 
 the fundamental body of the thionin dyes ; heating with aliphatic 
 
 /P TT \ 
 
 acids to 300 gives acridines (q.v.) like N C 6 H * CH. 
 
 Diphenylamine is used for preparing triphenyl-rosaniline (q.v.), or 
 aniline blue. 
 
 Methyl-diphenylamine CH 3 N(C 6 H 5 ) 2 , b.p. 292 (A. 235, 21). 
 
 Phenyl-p-toluidin C 6 H 5 NHC 6 H 4 CH 3 , m.p. 87; Phenyl-m-xylidin 
 C 6 H 5 NHC 6 H 3 (CH 3 ) 2 , m.p. 43, by methods 3 and 4. 
 
 Triphenylamine (C 6 H 5 ) 3 N, m.p. 127, distils without decomposition, 
 formed by heating dipotassium-aniline, or from sodium-diphenylamine 
 with bromo-benzol (B. 18, 2156). The easiest method is by heating 
 diphenylamine with iodo-benzol and some powdered copper ; or from 
 diphenyl-anthranilic acid by splitting off CO 2 (B. 40, 2448). It 
 crystallises from ether in large plates. It dissolves in hot H 2 SO 4 with 
 intense blue coloration. It does not form salts with acids. Nitro- 
 genation give.s a trinitro-product, from which, by reduction, triamido- 
 triphenylamine is formed (B. 19, 759). Phosgene gives hexaphenyl- 
 rosaniline (q.v.). 
 
 p-Tritolyl-amine (CH 3 C 6 H 4 ) 3 N, m.p. 117, from p-ditolyl-amine 
 and p-iodo-toluol. With Br, PC1 5 , SbCl 5 , etc., it gives dark-blue, 
 unstable addition products, decomposed by water with restoration of 
 tritolyl-amine (B. 46, 4268). 
 
 D. ANILINE DERIVATIVES OF INORGANIC ACIDS. 
 
 Aromatic thionylamines (Michaelis). These compounds, corre- 
 sponding to the alkyl- thionylamines (Vol. I.), are obtained by the action 
 of thionyl chloride upon primary bases, a reaction characteristic of 
 these compounds. 
 
 The thionyl-anilines are mostly yellow liquids, not decomposing 
 when boiling, even under increased pressure. They have an aromatic 
 odour, pervaded by the sulphur chloride smell. 
 
ANILINE DERIVATIVES OF INORGANIC ACIDS 93 
 
 Thionyl-aniline C 6 H 5 N : SO, b.p. 200, D 15 1-236. Thionyl- 
 o-chloraniline, b.p. 46 207 ; m-compound, b.p. 233 ; p-compound, 
 m.p. 36, b.p. 237. Thionyl-o-bromaniline, b.p. 46 210 ; m-compound, 
 m.p. 32 ; p-compound, m.p. 60. Thionyl-o-nitraniline, m.p. 32. 
 
 Thionyl-o-toluidin, b.p. 10 o I 84 ; m-compound, b.p. 220 ; p-com- 
 pound, m.p. 7, b.p. 224 (A. 274, 201), etc. 
 
 Phenyl-sulphaminic acid C 6 H 5 NHSO 3 H, known only in its salts, 
 formed (i) by the action of SO 3 or C1SO 3 H upon aniline, in chloroform 
 solution (B. 24, 360) ; (2) by heating aniline with amido-sulphonic 
 acid (B. 27, 1244) ; (3) by combining jS-phenyl-hydroxylamine with 
 SO 2 ; (4) by action of sodium bisulphite, or hydro-sulphite, upon 
 aqueous solutions of benzol (C. 1904, I. 1380 ; 1906, II. 37). 
 
 C 6 H 5 NO 2 +3HSO 3 Na=C 6 H 5 NHSO 3 Na-f2SO 4 HNa. 
 
 By dilute acids phenyl-sulphaminic acid is easily split up, with 
 formation of aniline salts ; while concentrated acids produce transposi- 
 tion into the o- and p-aniline-sulpho-acid (B. 30, 2274). 
 
 p-Tolyl-sulphaminie acid is precipitated from solution of its Am 
 salts by acids (B. 28, 3161). p-Chloro-phenyl-sulphaminic acid 
 C1C 6 H 4 NHSO 3 H is, on heating, transposed into p-Chloraniline-o- 
 sulphonic acid (B. 34, 2748). For formation of phenyl-sulphaminic 
 acids from anilines with SO 2 , see C. 1898, II. 195. Sulphanilide 
 S0 2 (NHC 6 H 5 ) a (B. 28, 362). 
 
 The aromatic nitroso-amines and nitro-amines are dealt with later, 
 before the diazo-compounds. 
 
 Phosphoro-phenylamines. Phosph-azo-benzol chloride C 6 H 5 N : PCI, 
 m.p. I36-I37, by action of PC1 3 upon aniline chlorohydrate. With 
 phenol it yields Phenoxyl-phosphazo-benzol C 6 H 5 N : P(OC 6 H 5 ). With 
 aniline, Phosphazo-benzol-anilide C 6 H 5 N : P.NHC 6 H 5 (B. 27, 490). 
 Anilido-phosphoric dichloride C 6 H 5 NH.POC1 2 , m.p. 84, from POC1 3 
 and aniline chlorohydrate (B. 26, 2939). Ortho-phosphoric anilide 
 (C 6 H 5 NH) 3 PO, m.p. 208 (A. 229, 334). Oxy-phosphazo-benzol- 
 anilide C 6 H 5 NH.PO : NC 6 H 5 , m.p. 357, is the final product of the 
 action of POC1 3 upon aniline (B. 29, 716 ; A. 326, 129). From aniline 
 chlorohydrate and PC1 5 we get trichloro-phosphanile C 6 H 5 N.PC1 3 
 (B. 28, 2212 ; cp. C. 1902, II. 355). 
 
 Sulpho-phosphazo-benzol chloride C 6 H 5 N : PSC1, m.p. 149, b.p. 
 28o-290, from PSC1 3 , and aniline chlorohydrate (B. 29, 1239). 
 
 Arseno-phenylamines are produced by the action of arsenious 
 chloride or bromide upon aniline in ether or chloroform. 
 
 Arsen-anilido-dichloride C 6 H 5 NHAsCl 2 , m.p. 87. Arsen-anilido- 
 dibromide, m.p. 112. Arsen-dianilido-monoehloride (C 6 H 5 NH) 2 AsCl, 
 m.p. 127. Arsen-anilido-dimethyl-ether C 6 H 5 NHAs(OCH 3 ) 2 , b.p. 12 55 
 (A. 261, 279). 
 
 Siiieo-tetraphenylamide Si(NHC 6 H 5 ) 4 , m.p. 137 (B. 22, R. 746), 
 passes on heating into Silico-diphenylimide Si(NC 6 H 5 ) 2 (C. 1903, 1. 572). 
 
 E. CARBOXYLIC DERIVATIVES OF THE AROMATIC PRIMARY AND 
 SECONDARY AMINES. 
 
 In the introduction to the fatty acids, it was explained, by the 
 example of acetic acid, which nitrogen derivatives could be obtained 
 
94 ORGANIC CHEMISTRY 
 
 by changes in the carboxyl group. The first category of compounds 
 are the carboxylic amides, which may be variously interpreted, 
 according to the formulae : 
 
 LR '- C \NH 2 and ILR/ - C <SH H - 
 
 The imido-ethers are derived from formula II. 
 
 Many such fatty-acid derivatives have been obtained, by starting 
 from aniline and its primary homologues. For the acid amides x>f 
 secondary bases only formula I. need be considered. In a primary 
 amine the two H atoms may be replaced by acid radicles. 
 
 The introduction of the second acidyl group is facilitated by 
 o-substituents in the aniline nucleus, which otherwise retard the 
 entry of the first acidyl group (C. 1901, I. 836). 
 
 To the acid amides correspond the thiamides and iso-thiamides : 
 
 LRC \NH 2 and n ' R <NH- 
 
 These classes of bodies are followed by the amido-chlorides, the 
 imido-chlorides, and the amidins. 
 
 Anilides of mono-basic fatty acids. The anilides or phenylamides 
 of the fatty acids are produced by the same methods (Vol. I.) as the 
 acid amides themselves : (i) by heating the aniline salts of the fatty 
 acids ; (2) by the action of aniline upon esters ; (3) upon acid chlorides ; 
 (4) upon acid anhydrides ; (5) by action of acid esters upon C 6 H 5 
 NHMgl (C. 1904, II. 201). 
 
 The acid amides are very stable ; they mostly distil without decom- 
 position, and can be chlorinated, brominated, and nitrogenated direct. 
 TJiey serve for the simple and quick identification of the aromatic 
 bases. By heating with alkalies, or with HC1, the anilides are again 
 split into their components. Boiling with sulphur converts them 
 into benzol- thiazols (q.v.). 
 
 The secondary anilides, like the secondary alkyl-anilines, form 
 nitroso-anilides with nitrous acid. With phenol, and sulphuric acid, 
 they give the nitrosamine reactions, but they are much less stable 
 than the nitrosamines of the secondary anilines ; by reducing agents 
 the nitroso-group is split off again. With hypochlorous and hypo- 
 bromic acids, the hydrogen attached to the nitrogen of the anilides 
 may be replaced by halogens : C 6 H 5 .NC1.COCH 3 ; these nitrogen 
 haloids are easily transposed under the influence of HC1, or sunlight, 
 into anilines with nuclear substitution, e.g. 
 
 C 6 H 5 NC1(COCH 3 ) - > C1[ 4 ]C 6 H 4 NHCOCH 3 
 
 (B. 32, 3573 ; C. 1903, I. 21, 141). 
 
 Formanilide C 6 H 5 NH.CHO, m.p. 46, b.p. 284 (A. 270, 279), is 
 produced on boiling aniline with formic acid, or during rapid heating 
 of aniline with oxalic acid. It is soluble in water, alcohol, and ether. 
 
 Salts and alkyl derivatives. From the aqueous solution, NaHO 
 precipitates Sodium formanilide C 6 H 6 N : (CHONa), in a crystalline 
 form, and with methyl iodide this gives Methyl formanilide 
 
 C H 5 N< \ C ^, m.p. 12-5, b.p. 253. By heating with alcoholic potash, 
 or HC1, the latter is split into acid, and methyl- aniline (B. 21, 1107). 
 
CARBOXYLIC DERIVATIVES OF AROMATIC AMINES 95 
 
 Silver formanilide C 6 H 6 N : CH(OAg) is precipitated from the alcoholic 
 solution of the sodium compound with silver nitrate, and passes, in 
 the presence of methyl iodide, into Methyl iso-formanilide C 6 H 5 .N : 
 CHOCH 3 , b.p. 196, which, on heating, is transposed into the isomeric 
 methyl formanilide (B. 23, 2274, R. 659). But the silver salt gives N 
 derivatives with acid chlorides, like benzoyl chloride (B. 29, R. 1141). 
 Ethyl iso-formanilide, ethoxy-methylene- aniline, C 6 H 5 N : CHOC 2 H 5 , 
 b.p. 212, is also obtained by prolonged boiling of aniline with 
 ortho-formic ester, besides diphenyl formamidin (A. 287, 360). 
 
 Acetanilide, antifebrin CeH 5 NHCOCH 3 , m.p. 114, b.p. 295, gene- 
 rated by boiling aniline with glacial acetic acid (B. 15, 1877) ; or 
 from aniline with acetyl chloride, acetic anhydride, or thio-acetic 
 acid ; the last of these agents has been found very useful for intro- 
 ducing acetyl groups into aniline (B. 35, no). 
 
 Acetanilide is also formed from malon-anilic acid by rejection of 
 CO 2 . A notable method is by treating the isomeric aceto-phenone 
 oxime with sulphuric acid at 100 (B. 26, 2581) : 
 
 C 6 H 5 C:(NOH).CH 3 > C 6 H 5 NH.CO.CH 3 . 
 
 Crystallised from water, in which it is not easily soluble in the cold, 
 acetanilide does not form white flakes. It is used as an anti-pyretic 
 and anti-rheumatic. For action of PC1 5 see A. 184, 86. Heating 
 with sulphur produces bis-thiazol (q.v.). 
 
 Brom-aeetanilide, m.p. 131, yields indigo (q.v.) on melting with 
 caustic potash in air. 
 
 Salts. The chlorohydrate is decomposed by water. On heating, 
 it passes into diphenyl-acet-amidin, flavanilin (q.v.) and dimethyl- 
 quinolin (B. 18, 1340). With sodium ethylate, on heating, it is con- 
 verted into ethyl- aniline and sodium acetate (B. 19, R. 680). 
 
 Sodium aeetanilide C 6 H 5 N : C(ONa)CH 3 , by action of sodium upon 
 the xylol solution of acetanilide, yields mono-alkyl-acetanilides with 
 alkylene iodide, and from these the mono-alkyl-anilines may be obtained 
 (B. 10, 328 ; 23, 2587). The same acetanilides are produced by the 
 action of acetic anhydride upon the secondary bases. But acetanilide, 
 heated with silver oxide, methyl iodide, or dimethyl sulphate, yields 
 
 Aeeto-phenyl-imido-methyl-ether CH 3 c^^ b.p. 197 (C. 1901, I. 
 1043; A. 333, 293). Mercurio-acetanilide (C 3 6 H 5 NCOCH 3 ) 2 Hg (B. 28, 
 R. 113). 
 
 Methyl-acetanilide, exalgin, m.p. 101, b.p. 253 (anti-neuralgic). 
 Ethyl-aeetanilide, m.p. 54, b.p. 258. n-Propyl-acetanilide, m.p. 47, 
 b.p. 266 (B. 21, 1108). 
 
 Substituted Acetanilides. The action of Cl, Br, and HNO 3 upon 
 acetanilide produces o- and p-derivatives. 
 
 Formyl aeetanilide C 6 H 5 N(COH)(COCH 3 ), m.p. 56, from mercurio- 
 formanilide and acetyl chloride (B. 29, R. 1155). 
 
 Diacetanilide C 6 H 5 N(COCH 3 ) 2 , m.p. 37, b.p. 1]L 142, by heating 
 acetanilide with acetyl chloride to i7O-i8o, or with acetic anhydride ; 
 also by boiling phenyl-mustard oil with acetic anhydride (B. 27, 91 ; 
 28, 1665). Its physiological effects are similar to those of acetanilide 
 (B. 31, 2788). 
 
 Concerning transpositions of diacetanilide into p - Acetamido - 
 
96 ORGANIC CHEMISTRY 
 
 aeetophenone, (CH 3 CO) 2 NC 6 H 5 > CH 3 CONHC 6 H 4 COCH 3 , see C. 
 
 1902, II. 355 ; 1903, I. 1222. 
 
 The acetic compounds are distinguished for their power of crystal- 
 lisation. They serve as means of recognising many primary and 
 secondanr aromatic bases. Hence the melting-points of many 
 acetic compounds have been quoted in connection with the bases 
 concerned. 
 
 Thio-anilides are formed from the anilides with P 2 S 5 ; or from 
 amidins and isonitrites with H 2 S ; or from phenyl-mustard oil with 
 magnesium-alkyi iodides. 
 
 Thio-formanilide C 6 H 5 NHCHS melts at 137, with decomposition 
 into H 2 S and phenyl iso-cyanide (B. 11, 338 ; A. 192, 85). For 
 homologous thio-formanilides, see B. 18, 2292. 
 
 Thio-aeetanilide, m.p. 75, oxidised with potassium ferricyanide, 
 
 passes into Amido-thio-phenol C 6 H 4 <f^C.CH 3 (B. 19, 1072). Thio- 
 anilides of homologous fatty acids, B. 36, 587. Methyl-thio-acetanilide, 
 m.p. 59, b.p. 290. 
 
 Methyl-iso-thio-acetanilide C 8 H 5 N:C<(^, b.p. 245, Ethyl-iso- 
 
 thio-acetanilide, b.p. 250, formed by action of sodium alcoholate and 
 alkyl iodides upon thio-acetanilide. On shaking with HC1 they 
 decompose into aniline chlorohydrate and thio-acetic ester (Vol. I.) 
 (B. 12, 1061). 
 
 F. PHENYLATED AMIDINS OF FORMIC ACID AND ACETIC ACID. 
 
 Besides the general methods of amidin formation, enumerated 
 in Vol. I., the phenylated amidins are prepared by action of PC1 3 or 
 HC1 upon a mixture of aniline and anilide, with liberation of water 
 (B. 15, 208, 2449) : 
 
 C 6 H 5 NHCOCH 3 +C H 6 NH 2 = 
 
 They are feeble bases, and combine with i equiv. HC1 to form 
 salts. On boiling with alcohol they decompose into aniline and 
 acid anilides. 
 
 Diphenyl - f ormamidin, methenyl - diphenyl - diamine C 6 H 5 N : CH. 
 NHC 6 H 5 , m.p. 135, by heating aniline to 180 with chloroform or 
 formic acid; from hydrocyanic sesqui-chlorohydrate (CHN) 2 (HC1) 3 
 with aniline (B. 35, 2498) ; or by boiling phenyl-iso-cyanide C 6 Hg.NC 
 with aniline. It crystallises from alcohol in long needles, and distils 
 at about 250, with partial decomposition, into benzo-nitrile and 
 aniline. 
 
 Di-aryl-form amidins are distinguished from the amidins of the 
 higher carboxylic acids by their superior power of reaction. With 
 the CH 2 group of malonic ester, aceto-acetic ester, and similar sub- 
 stances, they react with liberation of aniline, and formation of 
 aniline-methylene derivatives like: C 6 H 5 NHCH : C(CO 2 R) 2 Anilino- 
 methylene- malonic ester, C 6 H 5 NHCH : C(COCH 3 )CO 2 R Anilino- 
 methylene-aeetic ester, etc. (B. 35, 2505). 
 
 Diphenyl-oxy-f ormamidin melts without water at 131 ; formed 
 
PHENYLATED CARBYLAMINES 97 
 
 from methyl-iso-formanilide with j3-phenyl-hydroxylamine a l so from 
 methylene-diphenyl-hydroxylamine by withdrawing H 2 O, by means 
 of anhydrous copper sulphate. Acetic anhydride transposes it into 
 diphenyl-urea C 6 H 5 NH.CO.NHC 6 H 5 (B. 35, 1451, 1874). 
 
 Diphenyl-ethenyl-amidin melts at 131, formed by addition of 
 CH 3 .MgI to carbo-diphenyl-imide (q.v.). 
 
 Phenyl-ethenyl-amidin C 6 H 5 .N : C(NH 2 ).CH3, from aceto-nitrile and 
 HCl-aniline (A. 184, 362 ; 192, 25) (Vol. I.) is liquid. 
 
 Phenylisuretin CgHgNH-CH : NOH, m.p. 138, from formyl- 
 chloridoxime (Vol. I.) with aniline (B. 27, R. 745). 
 
 PHENYLATED CARBYLAMINES (Vol. I.). Phenyl-isoeyanide,^n>'J- 
 carbylamine, boils, at atmospheric pressure, at 166 with strong poly- 
 merisation, below 20 mm. at 64 without change. The colourless 
 liquid, D 15 0-977, soon colours a light blue, then dark blue, and turns 
 resinous. Phenyl-isocyanide is formed from aniline and chloroform, 
 with alcoholic potash, also by heating thio-formanilide. Phenyl- 
 carbylamine has an abominable and clinging odour, tastes bitter, and 
 causes headache and flow of saliva. It behaves as follows : Heating 
 to 220 transposes it into benzo-nitrile C 6 H 5 CN. Nascent H converts 
 it into methyl-aniline. With HC1 in dry ether it gives phenyl-imido- 
 formyl-chloride ; with glacial acetic acid, formanilide ; with SH 2 at 
 100, thio-formanilide ; with sulphur at 130, mustard oil ; with aniline 
 at 170, diphenyl-formamidin ; with chlorine, isocyano-phenyl-chloride 
 or phenyl-amido-carbonyl-chloride; with phosgene, meso-xanil-amido- 
 chloride ; with acetyl chloride, pyro-racemic anilide chloride (Nef , 
 A. 270, 274). o-Tolyl-isoeyanide, b.p. 16 75, D 24 0-968. p-Tolyl- 
 isocyanide, b.p. 32 99 (B. 27, R. 792). 
 
 PHEXYLAMIXE DERIVATIVES OF OXY-ACIDS. These compounds are 
 capable of some condensation reactions, in which the benzene H atom, 
 in ort/jo-position to nitrogen, often takes part, so that heterocyclic 
 compounds are formed. The acids are obtained by heating the corre- 
 sponding halogen fatty acids with anilines (cp. B. 30, 2303, 2464, 3169 ; 
 31, 2678). Their nitriles are formed : (i) by addition of HCN to the 
 alkylidene-anilines ; (2) from the bisulphite addition-products of the 
 latter with CNK (C. 1902, II. 315 ; B. 37, 4073) ; (3) by heating the 
 aldehyde and ketone cyano-hydrins with aniline ; (4) by direct trans- 
 formations of aniline salts with aldehydes, or ketones, and CNK (B. 39, 
 986, 2796). 
 
 Anilido-aeetie acid, phenyl-glycocoll, phenyl-glycin C 6 H 5 NHCH 2 
 COOH, m.p. 127, by heating chloro- or bromo-acetic acid with aniline 
 and water (B. 10, 2046 ; 21, R. 136). Its alkyl esters are obtained by 
 heating aniline with chloracetic ester or dichloro-vinyl ether in aqueous 
 suspension (C. 1908, I. 1006 ; II. 358), or by action of diazo-acetic 
 ester upon aniline. Its nitrile, m.p. 43, is formed (i) from anhydro- 
 formaldehyde-aniline with absolute HCN ; (2) from its bisulphite com- 
 pounds with CNK ; (3) from formaldehyde-cyanhydrin with aniline ; 
 (4) from aniline chlorohydrate, formaldehyde, and CNK (C. 1902, II. 
 315 ; 1903, I. 208 ; 1904, I. 1308). By heating the free acid to 
 150 we obtain Diphenyl-glycin-anhydride or diphenyl-diacipiperazine 
 C 6 H 5 N^^ CO\ NC6 H 6 , m.p. 263 (B. 25, 2270). Phenyl-glycin 
 
 -LAJ L,rl 2 / 
 
 possesses industrial importance, since, on melting with caustic potash, 
 VOL. II. H 
 
98 ORGANIC CHEMISTRY 
 
 or, better, sodium amide, it passes into indoxyl C 6 H 4 <^ ( yCH, which, 
 
 in air, easily oxidises to indigo. 
 
 Distillation of calcium anilido-acetate with Ca formate gives indol 
 
 </-"TT vx 
 l^tl \pTT 
 NH/ C 
 
 Besides phenyl-glycin we obtain from aniline and chloracetic acid 
 Diglycol-phenyl-amidic acid, anilino-diacetic acid C 6 H 5 N(CH 2 COOH) 2 , 
 m.p. I5o-i55. Oxidised with MnO 4 K it gives Formyl-phenyl-glycin 
 C 6 H5N(CHO)CH 2 COOH, m.p. 125. It is better obtained from phenyl- 
 glycin by heating with formic acid (B. 34, 1647). 
 
 Diglycol-phenyl-amidic anhydride C 6 H 5 N(CH 2 CO) 2 O, m.p. 148 
 (B. 25, 2272) ; imide, C 6 H 5 N(CH 2 CO) 2 NH, m.p. 158 (B. 22, 1809) ; 
 anile C 6 H 5 N(CH 2 CO) 2 NC 6 H 5 , m.p. 152 (B. 22, 1802). Isomeric with 
 
 diglycol-phenyl-amidic acid is Diglycol-anilic acid O / CH2CONHC6H5 , 
 
 \CH 2 CO 2 H 
 
 m.p. 118, from diglycolic anhydride and aniline. With acetyl chloride 
 it passes into Diglycolic anile O(CH 2 CO) 2 NC 6 H 5 , m.p. 116, isomeric 
 with diglycol-phenyl-amidic anhydride (A. 273, 66). Thio-diglyeol- 
 anilic acid and anilide, see A. 273, 70. 
 
 Methyl-phenyl-glycin C 6 H 5 (CH 3 )NCH 2 COOH, by heating methyl- 
 aniline with chloracetic acid. The nitrile, b.p. 266, is obtained by the 
 action of methyl-aniline upon formaldehyde-cyano-hydrin. Amide, 
 m.p. 163 (B. 37, 2636). 
 
 Dimethyl-phenyl-betamC 6 H 5 N(CH 3 ) 2 CH 2 COO+H 2 O, m.p. 124, by 
 the action of chloracetic acid upon dimethyl-aniline. On heating it is 
 transformed into Methyl-phenyl-glyeocoll-methyl ester, b.p. 10 141. 
 
 o-Nitro-phenyl-glyein NO 2 [2]C 6 H 4 [i]NHCH 2 CO 2 H, m.p. 193. 
 
 a-Anilido-propionic acid, phenyl-alanin C 6 H 5 NHCH(CH 3 )COOH, 
 m.p. 162, is obtained from its nitrile, the transformation product of 
 ethylidene-cyano-hydrin with aniline, and of ethylidene- aniline with 
 HCN (B. 15, 2036 ; 23, 2010 ; 25, 2032). a-Anilido-butyric acid 
 C 6 H 5 NHC(CH 3 ) 2 COOH, m.p. 185; nitrile, m.p. 94 (B. 39, 989). 
 ^-Anilido-propionic ester, b.p. ls 175, from jS-iodo-propionic ester (B. 
 29, 514). j8-Anilido-aliphatic acids are also formed by attachment of 
 aniline to olefin-carboxylic acids (B. 36, 1262). 
 
 Dianilido-acetic acid (C 6 H 5 NH) 2 CHCOOH, m.p. 88 -o,3, by action 
 of aniline upon diacetyl-glyoxylic acid. It easily splits off i mol. 
 aniline and forms anyl-glyoxylic acid. Heating with aniline and its 
 chlorohydrate, it is transformed into p, p-diamido-diphenyl-acetic acid 
 (q.v.) (B. 41, 3031, 4264). 
 
 ANILINE DERIVATIVES OF KETONE-CARBOXYLIC ACIDS. Pyro- 
 racemic anilide CH 3 .CO.CONC 6 H 5 , m.p. 104. Pyro-racemic anilide 
 chloride CH 3 .CO.CC1 : NC 6 H 5 , m.p. 136, from phenyl-carbylamine 
 (q.v.) and acetyl chloride (A. 270, 299). Anile-pyro-raeemic acid 
 
 C 6 H 6 N : C <> ni.p. 122 with decomposition, formed from aniline 
 
 and pyro-racemic acid in ether (A. 263, 126) ; passes easily into 
 anile-uvitoninic acid, a derivative of quinolin. 
 
 Aceto-acetic anilide CH 3 CO.CH 2 CONHC 6 H 5 , m.p. 85, formed from 
 aceto-acetic ester and aniline at 130. May be condensed to y-methyl- 
 carbostyrile (q.v.). Anile-aceto-acetic ester, p-pfonyl-imido-butyric ester 
 
ANILINE DERIVATIVES OF CARBONIC ACID 99 
 
 C 6 H 6 N : c/ CH co c H ", or 6-Anilido-erotonic ester 
 
 \CH 3 
 
 b.p. 16 165, from aniline and aceto-acetic ester at ordinary tempera- 
 tures. It adds HCN, like the alkylidene-anilines, which speaks for 
 the anile formula (B. 35, 2080). By alkalies, and acids, it is split up 
 into its generators. By heating at ordinary pressures it may be con- 
 densed to y-oxy-quinaldin (q.v.) and phenyl-lutidone-carboxylic acid 
 (q.v.) (B. 20, 947, 1398 ; 22, 83). A similar behaviour is shown by the 
 tolyl-amido-compounds. 
 
 ANILINE DERIVATIVES OF CARBONIC ACID. The numerous com- 
 pounds of this class are treated in the same order as the amine and 
 alkylamine derivatives of carbonic acid, with which they can be thus 
 most conveniently compared (see Vol. I.). 
 
 Carbanilic acid, phenyl-carbaminic acid, is unknown in the free state. 
 Its salts are obtained by the action of very dilute alkalies, or alkaline- 
 earth hydroxides, upon phenyl isocyanate. On acidulating, even 
 with carbonic acid, the salts immediately break up into aniline and 
 CO 2 . Their esters, the Phenyl-urethanes, are obtained : (i) from 
 aniline and chloro-carbonic acid esters (B. 18, 978) ; (2) from car- 
 banile and alcohols (B. 3, 654) ; (3) from urea chlorides and alcohols 
 (B. 24, 2108) ; (4) from benzoyl azide with alcohols (cp. Vol. I., and 
 B. 29, R. 181). 
 
 Methyl ester C 6 H 5 NH.CO 2 CH 3 , m.p. 47, with sulphuric acid passes 
 into amido-sulpho-benzoic ester (B. 18, 980). Ethyl ester, m.p. 52. 
 
 Urea chlorides are formed from secondary aromatic bases, and 
 phosgene in benzene solution (B. 23, 424). Phenyl-urea chloride 
 C 6 H 5 NH.COC1, m.p. 59, and bromide, m.p. 67 (B. 28, R. 777). 
 Methyl-phenyl-urea chloride (CH 3 )(C 6 H 5 )N.COC1, m.p. 88, b.p. 280. 
 Diphenyl-urea chloride (C 6 H 5 ) 2 N.COC1, m.p. 85. With benzene and 
 Al chloride they pass into the amides of benzoic acid (B. 20, 2118 ; 
 
 24, 2108) ; cp. the syntheses of aromatic carboxylic acids. Sodium, 
 in ether, converts di-p-tolyl-urea chloride, m.p. 102, into a tetra- 
 substituted oxamide (B. 25, 1819, 1825). 
 
 PHENYLATED UREAS. Phenyl-urea NH 2 CONHC 6 H 5 , m.p. 144 : (i) 
 from cyanic acid and aniline, by evaporation of a solution of aniline 
 chlorohydrate with potassium isocyanate (B. 9, 820) ; (2) from am- 
 monia and carbanile. 
 
 Sym. alkyl-phenyl-ureas are produced by the action of aniline 
 upon isocyanic ester, or of phenyl isocyanate upon alkylamine. 
 Sym. alkyl-phenyl-urea C 2 H 5 NHCONHC 6 H 5 , m.p. 99. 
 
 Asym. alkyl-phenyl-ureas from alkyl-aniline chlorohydrate and 
 potassium isocyanate, as ethyl-phenyl urea, m.p. 62. 
 
 Sym. diphenyl-urea, carbanilide CO(NHC 6 H 5 ) 2 , m.p. 235, b.p. 
 260, formed (i) from phosgene and aniline (B. 16, 2301) ; (2) from 
 phenol isocyanate and aniline (A. 74, 13) ; (3) from s-diphenyl- 
 sulpho-urea, with mercuric oxide, or alcoholic potash (A. 70, 148) ; 
 (4) from aniline, and urea at 170 ; (5) from monophenyl-urea, and 
 aniline at 190 (B. 9, 820) ; (6) from diphenyl carbonate, with aniline, 
 at 170 (B. 18, 516) ; (7) from oxanilide, by heating with HgO (M. 
 
 25, 375) ; (8) from phenyl isocyanate and water, carbanilide forms 
 needles of a silky lustre, easily soluble in alcohol and ether, slightly 
 soluble in water. 
 
TOO ORGANIC CHEMISTRY 
 
 as-Diphenyl-urea C 6 H 5 NH.CO.N(C 6 H 5 ) 2 , m.p. 132, and Tetra- 
 phenyl-urea (C 6 H 5 ) 2 N.CO.N(C 6 H 5 ) 2 , m.p. 183, are also obtained 
 from diphenyl-urea (B. 37, 963). 
 
 CYCLIC ALKYLENE-PHENYL-UREA DERIVATIVES (cp. Vol. I.). 
 Ethylene-phenyl-urea, see B. 24, 2192. Trimethylene-phenyl-urea 
 (B. 23, 1173). 
 
 Ethylene-carbanilide OO^J^S'- m -P- l8 3 ( B - 20 > 784)- Trl- 
 
 \IN(C 6 H. 6 )CJdL 2 
 
 methylene-carbanilide, m.p. 153 (B. 20, 783). 
 
 Ureids of the Phenylated Ureas of Mono-carboxylic Acids. Acetyl- 
 phenyl-urea CH 3 CONH.CO.NHC 6 H 5 , m.p. 183, from phenyl-urea 
 with acetic anhydride or acetyl chloride (B. 8, 1181), and from 
 phenyl isocyanate and aceto-chloramide (C. 1904, I. 241). Acetyl- 
 carbanilide C 6 H 5 NH.CO.N(COCH 3 )C 6 H 5 , m.p. 115 (B. 17, 2882). 
 
 Ureids of Oxy-acids. Glycol-phenyl-urea, phenyl-hydanto'in, m.p. 
 194, from phenyl-glycin and urea at 160 ; also from chloracetyl- 
 urethane with aniline (C. 1899, II. 420 ; /. pr. Ch. 2, 66, 231 ; homo- 
 logues, see C. 1906, I. 461). Diphenyl-hydantom, m.p. 139 (B. 25, 
 2274). 
 
 Phenylated Pseudo-Urea Derivatives are obtained from phenylated 
 cyanamides, with alcohols and HC1, as are the imido-ethers from 
 nitriles. 
 
 Methyl-phenyl-iso-urea C 6 H 5 NHC(OCH 3 ) : NH, see C. 1901, II. 
 919. Ethyl - phenyl -iso- urea C 6 H 5 NH.C(OC 2 H 5 ) : NH, b.p. 19 138. 
 Ethyl-phenyl-methyl-iso-urea C 6 H 5 N(CH 3 ).C(OC 2 H 5 ) : NH, b.p. 21 137 
 (B. 32, 1494; 33, 807). Ethyl-diphenyl-iso-urea, anilido-phenyl- 
 carbaminic ethyl ether C 6 H 5 N : C(OC 2 H 5 )NHC 6 H 5 , an oil, b.p. 2;) 200. 
 Methyl-ditolyl-iso-urea, m.p. 48, b.p. n 199, generated from the car- 
 bodi-phenylimides with alcohol at i8o-i9O, or, better, with Na 
 alcoholates, give with HC1 addition products. By acids they are 
 easily split up, but with alkalies and amines they are stable (C. 1899, 
 
 I. 828). Triphenyl-ehloro-carbamidin CIC \^*H )S > m -P- 92, formed 
 
 by action of PC1 5 upon triphenyl-urea ; gives, with Na ethylate, 
 ethyl-iso-triphenyl-urea C 6 H 5 N : C(OC 2 H 5 )N(C 6 H 5 ) 2 , m.p. 49 (B. 
 37, 964). 
 
 Phenylated Ureids of Carbonic Acid. Phenyl - allophanie ester 
 C 6 H 6 NH.CO.NHCO 2 C 2 H 5 , m.p. 120 (/. pr. Ch. 2, 32, 18). Diphenyl- 
 allophanic acid, see B. 4, 246. Sym. Phenyl-biuret C 6 H 5 .N : (CONH 2 ) 2 , 
 m.p. 192, from phenyl-urea and PC1 3 . as-Phenyl-biuret C 6 H 5 NH. 
 CONH.CO.NH 2 , m.p. 167 (A. 352, 73). Diphenyl-biuret C 6 H 5 NH. 
 CONH.CO.NHC 6 H 5 , m.p. 210 (B. 4, 265), by heating phenyl-urea 
 with excess of phosgene. Triphenyl-biuret, m.p. 147 (B. 4, 250). 
 
 PHENYLATED HYDROXYLAMINE AND HYDRAZIN DERIVATIVES OF 
 UREA. Phenyl-hydroxyl-urea C 6 H 5 NH.CO.NHOH, melts at 140 with 
 decomposition, formed from carbonile and hydroxylamine chloro- 
 hydrate (A. 263, 264). 
 
 Phenyl - semicarbazide, phenyl - carbaminic hydrazide C 6 H 5 NH. 
 CO.NH.NH 2 , m.p. 120, isomeric with carbaminic hydrazide (q.v.), 
 formed (i) from its acetyl derivative, m.p. 169, formed on boiling 
 benzo-acid with aceto-hydrazide in acetone, with liberation of nitrogen : 
 
 C 6 H 5 CON 8 -i-NH 2 NH.COCH 3 =C 6 H 5 NH.CO.NHNH.COCH 3 -fN 2 ; 
 
DERIVATIVES OF THIO-CARBAMINIC ACIDS 101 
 
 (2) by splitting up acetone phenyl-semicarbazone (CH 3 ) 2 C : NNH. 
 CO.NHC 6 H 5 , which is easily obtained by heating aniline with acetone 
 semi-carbazone (B. 38, 831) ; (3) from phenyl-urea with hydrazin 
 hydrate. 
 
 Hydrazi-diearbon-anilide C 6 H 5 NH.CO.NHNH.CONHC 6 H 5 , m.p. 
 245, from phenyl-semicarbazide by heating ; it is oxidised to azo- 
 di-carbon-anilide C 6 H 5 NHCO.N : N.CONHC 6 H 5 , m.p. 183. Phenyl- 
 carbamic azide C 6 H 5 NH.CON 3 , m.p. 104. In contrast with other 
 carboxylic azides it is split by water, or alcohol, into nitrogen hydride, 
 and carbaminic acid, and their esters (/. pr. Ch. 2, 58, 205). 
 
 PHENYLATED DERIVATIVES OF THE THIO-CARBAMINIC ACIDS AND OF 
 THIO-UREA. Phenyl-carbaminic thio-methyl ester C 6 H 5 .NH.COSCH 3 , 
 m.p. 83, and ethyl ester, m.p. 74, fromdiphenyl-amidin-thio-alkylene, 
 heated with dilute sulphuric acid to 180 (B. 15, 339). 
 
 Phenyl-sulphur-ethane, xanthogen-anilide, thio-carbanilic ethyl ester 
 C 6 H 5 NHCS.OC 2 H 5 or C 6 H 5 N : C(SH)OC 2 H 5 , m.p. 71, from phenyl- 
 mustard oil, with alcohol at 120, or with alcoholic potash. With 
 primary and secondary bases it changes into phenyl-sulpho-ureas. 
 On distilling, it decomposes into phenyl-mustard oil and alcohol 
 (B. 15, 1307, 2164). Oxidised with alkaline potassium ferri- 
 cyanide, it passes into ethoxy-mustard oil and ethoxy-benzo-thiazol 
 
 C.H 4 <^; C.OC 2 H 5 . In alkalies it dissolves like the phenol-thio-ureas, 
 and makes metallic compounds with silver, mercury, and lead. 
 
 Phenyl-imido-thio-carboxylic acid C 6 H 5 N : c/^ [ is unknown. Its 
 
 \brl 
 
 ethers are formed by the action of alkyl iodides upon the metallic com- 
 binations of the phenyl-sulphur-ethanes and upon the free phenyl- 
 sulphur-ethanes. A similar behaviour is shown by the thio-acetanilides 
 and the phenyl-sulpho-ureas. Ethyl-methyl ester C 6 H 5 N : 
 
 b.p. 260. Diethyl ester, m.p. 30 (A. 207, 148). 
 
 PHENYL-DITHIO-CARBAMINIC ACID DERIVATIVES. The free acid, 
 precipitated from the potassium salt, decomposes into aniline and 
 SC 2 . Its potassium salt, C 6 H 5 NHCSSNH 4 , is formed from aniline, 
 CS 2 , and aqueous ammonia (/. pr. Ch. 2, 65, 369). For further 
 aryl-dithio-carbaminates, see B. 40, 2970. 
 
 Phenyl-dithio-carbaminie methyl ester, m.p. 87, and phenyl-dithio- 
 urethane, m.p. 60, formed by heating phenyl-mustard oil with mer- 
 captans, which split again at higher temperatures. They dissolve in 
 alkalies. 
 
 Ethyl-phenyl-dithio-urethane (C 2 H 5 )C 6 H 5 NCSSC 2 H 5 , m.p. 68, b.p. 
 310, from diphenyl-pseudo-ethyl-thio-urea, with CS 2 at 160. This 
 compound is very stable, does not dissolve in alkalies, and is not freed 
 from sulphur by HgO, or alkaline lead solutions. On heating with 
 methyl iodide the phenyl-dithio-urethanes, like phenyl-sulphur-ethane, 
 and diphenyl-sulpho-urea, form addition products. 
 
 Phenyl-thiuram-sulphide S(CSNHC 6 H 5 ) 2 , m.p. 137 (B. 24, 3023). 
 
 Methyl-phenyl-thio-carbamine chloride (CH 3 )C 6 H 5 N.CSC1, m.p. 35, 
 from methyl-aniline and thio-phosgene (B. 20, 1631). 
 
 PHENYL - SULPHO - UREAS. Phenyl - sulpho - urea, sulpho-carbanile- 
 amide NH 2 CSNHC 6 H 5 , m.p. 154, from phenyl-mustard oil and ammonia, 
 
102 ORGANIC CHEMISTRY 
 
 or from ammonium phenyl-dithio-carbaminate with Pb carbonate 
 (/. pr. Ch. 2, 65, 369). On boiling with silver nitrate it passes into 
 phenyl-urea ; with HgO into phenyl cyanamide ; with bromine, in 
 chloroform solution, phenyl- thio-urea gives the bromide of a disulphide 
 C 6 H 5 N : C(NH 2 )SSC(NH 2 ) : NC 6 H 5 , m.p. 128 (B. 34, 3130) ; with 
 methyl iodide it combines to form the iodo-hydrate of n-phenyl- 
 methyl-pseudo-thio-urea. With acetic anhydride the unstable as- 
 phenyl-aeetyl-thio-urea, m.p. 145, is formed at first, which, on heating 
 above the m.p., is transformed into the symmetrical variety 
 C 6 H 5 .NH.CSNH.COCH 3 , m.p. 171 (C. 1902, I. 1300; 1908, I. 1541). 
 These reactions are generally applicable to aromatic thio-ureas. 
 
 s-Diphenyl-sulpho-urea, sulpho-carbanilide CS(NHC 6 H 5 ) 2 , m.p. 
 151, brilliant colourless flakes, easily soluble in alcohol (B. 19, 1821). 
 Formed : (i) from phenyl-mustard oil, and aniline, in alcoholic solution ; 
 (2) by boiling aniline with CS 2 , and withdrawing SH 2 . The formation 
 of the urea is greatly favoured by the addition of sulphur or hydrogen 
 peroxide (B. 39, 4369). 
 
 Reactions of sulpho-carbanilide are known in great number : 
 
 (1) Iodine converts it into sulpho-carbanile and a-triphenyl-guanidin. 
 
 (2) Boiling with concentrated HC1 splits it up into phenyl-mustard oil, 
 and aniline (B. 16, 2016). (3) Extraction of sulphur with HgO pro- 
 duces the symmetrical diphenyl-urea. (4) In benzene solution with 
 HgO, carbo-diphenyl-imide is formed. (5) With ammonia, and Pb 2 O, 
 we obtain diphenyl-guanidin ; with aniline, triphenyl-guanidin ; with 
 hydroxylamine, oximido-diphenyl-urea (C 6 H 5 NH) 2 C : NOH ; with 
 hydrazin hydrate, in the presence of alkalies, amido - diphenyl- 
 guanidin, etc. 
 
 Phenyl- and symmetrical diphenyl-sulpho-ureas, dissolved in alkalies, 
 form salts in which the metal adheres to the sulphur (cp. thio- 
 acetanilide). 
 
 As to alkyl-phenyl-sulpho-ureas, see B. 17, 2088 ; 23, 815 ; 26, 1686. 
 as-Diphenyl-sulpho-urea, m.p. 198, from diphenyl-amine-rhodanide 
 (B. 26, R. 607). Triphenyl-thio-urea, m.p. 152 (B. 17, 2092). Tetra- 
 phenyl-thio-urea (C 6 H5) 2 N.CS.N(C 6 H 5 ) 2 , m.p. 195, is generated by 
 heating triphenyl-guanidin with CS 2 (B. 15, 1530). 
 
 Phenyl-sulpho-hydantoins. While the product formerly taken for 
 thio- or sulpho-hydantoin has turned out to be pseudo-hydantoin, 
 aromatic phenyl-sulpho-hydantoins have become known (B. 24, 3278). 
 
 Phenyl-a-methyl-sulpho-hydantoin SC<^ HS) O 
 
 \ .N H CrlCrl 3 
 
 m.p. 184, by melting phenyl-mustard oil 
 
 x-g 
 
 and alanin together. 
 
 PHENYLATED PSEUDO - SULPHO - UREA DERIVATIVES. Such com- 
 pounds are obtained, e.g., from phenyl- and symmetrical diphenyl- 
 sulpho-urea by the action of alkyl iodides and caustic potash, or, 
 better, by heating with alkyl iodides or bromides in alcoholic solution 
 (B. 25, 48). In the latter case we get the iodo-hydrate of a base 
 which is precipitated by sodium-carbonate solution, and may again 
 add halogen alkyl. On heating with alcoholic potash, the imido- 
 phenyl-carbaminic thio-ester splits off mercaptans. 
 
 n-Phenyl-methyl-pseudo-thio-urea, imido-phenyl-carbaminic thio- 
 
PHENYLATED DERIVATIVES OF THIO-UREA 103 
 
 methyl ester C H5 ^^CSCH 3 , m.p. 71. Sym. diphenyl - pseudo - 
 methyl - thio - urea, phenyl-imido-phenyl-carbaminic thio-methyl ester 
 
 ;")C.SCH 3 , m.p. 110. On heating with dilute sulphuric acid, 
 C 6 H 5 N-^ 
 
 both yield phenyl-carbaminic thio-methyl ester, which proves the 
 adhesion of the methyl to sulphur. With alcoholic ammonia at 120, 
 phenyl-guanidin and mercaptan are formed. Heated with CS 2 , the 
 diphenyl-pseudo-methyl-thio-urea passes into phenyl-mustard oil and 
 phenyl-dithio-carbaminic ester (B. 15, 343). Phenyl-pseudo-methyl- 
 thio-urea gives, with acetyl chloride, an as-acetyl derivative, m.p. 86, 
 which, on heating, passes into the symmetrical form (C. 1902, I. 1300). 
 With CH 2 I 2 , CH 2 Br.CH 2 Br, and CH 2 Br.CH 2 .CH 2 Br, diphenyl- 
 thio-urea gives cyclic derivatives of pseudo-sulpho-urea (B. 21, 1872) : 
 
 C.H 6 N:C/ N < C ' H *>>CH 2 C,H 5 N : C/N(C.H 5 ).CH 2 ^^ . c /N(C H S ).CH, 
 \S ' \S - Cri2 ^S CH2~Cri2 
 
 The ethylene derivative contains the so-called thi-azol ring ; the tri- 
 methylene derivative, the next higher penthi-azol ring, which is homo- 
 logous with the thi-azol ring. 
 
 Triphenyl-pseudo-thio-urea (C ^ 2 ^)c.s.c 6 H 5 , m.p. i85-i88, by 
 
 transformation of triphenyl-chloro-carbamidin with sodium-thiophenol 
 (B. 36, 965). 
 
 Pseudo-phenyl-thiohydantoinic acid HN : c/: 5 . m.p. 150 
 
 \SCH 2 CO 2 H 
 
 (C. 1898, II. 296), and Pseudo - diphenyl - thiohydantoinic acid 
 C 6 H 5 N : C <^ ( ^ 6 C ^ ) 5 H > formed from phenyl- and diphenyl-thio-urea with 
 
 chloracetic acid. By rejecting water, these compounds pass into 
 pseudo-hydantoins : unstable Pseudo - phenyl - thiohydantoln 
 HN . c< /N(CeH5).co ^ mp I48 o^ from Rhodan-acetanilide CNS.CH 2 
 
 CONHC 6 H 5 , m.p. 91, by heating to 100, and on further heating it 
 forms a stable isomeric C 6 H 5 N : C/^ H '^ m.p. 178 ; on boiling with 
 
 NO 
 
 HC1, the latter splits up, to form pseudo-phenyl-thiohydantomic acid, 
 and, subsequently, forms a mixture of aceto-iso-thiocyanic acid and 
 phenyl-aceto-iso-thiocyanic acid co/^^^ (C. 1902, II. 792). 
 The latter is also formed by the breaking up of Pseudo-diphenyl- 
 thiohydantoln C 6 H 5 N : c<^ c H s)-<;O , m . p . I7 6. 
 
 \o - v^.H-2 
 
 HYDROXYLAMINE AND HYDRAZIN DERIVATIVES OF THE PHENY- 
 LATED THIO-UREAS. Phenyl - hydroxyl - thio - urea C 6 H 5 NHCSNHOH, 
 
 m.p. 106, from hydroxylamine and phenyl-mustard oil, is easily 
 decomposed into water, sulphur, and phenyl cyanamide (B. 24, 378). 
 
 Phenyl-thio-semiearbazide, phenyl-thiocarbaminic hydrazide C 6 H 5 
 NH.CS.NH.NH 2 , m.p. 140, from phenyl-mustard oil and hydrazin 
 hydrate ; or from diphenyl-sulpho-urea with hydrazin hydrate in 
 alcoholic solution (B. 33, 1058). With aldehydes it is transformed into 
 phenyl-thio-semicarbazones. Its acyl derivatives easily yield thio- 
 bi-azolins (q.v.) with rejection of water. A peculiar behaviour is shown 
 by the benzoyl derivative, which, when deprived of H 2 O by means 
 
104 ORGANIC CHEMISTRY 
 
 of acetyl chloride, yields a phenyl-imido-phenyl-thio-bi-azolin ; or by 
 means of benzoyl chloride, a diphenyl-triazol mercaptan (B. 29, 2914) : 
 
 C 6 H 6 N : c/ NH ~ N ^-C 6 H 5 NH.CS.NHNH.COC 6 H 5 ~>C 6 H 5 N < C ( C 6 H 5) : N . 
 
 X S - C.C 6 H 6 HSC -- N 
 
 Phenylated Guanidin Derivatives. Phenyl-guanidin NH : c 
 
 m.p. 60, from cyanamide and aniline chlorohydrate. By an analogous 
 process we obtain Diphenyl-guanidin, melanilin NH : C(NHC 6 H 5 ) 2 , 
 m.p. 147, from cyananilid (p. 106) and aniline chlorohydrate, and also 
 by the action of C1CN upon dry aniline. Both, like guanidin itself, are 
 mono-acid bases. CS 2 decomposes diphenyl-guanidin into diphenyl- 
 sulpho-urea and KSCN. 
 
 a-Triphenyl-guanidin C 6 H 5 N : C(NHC 6 H 5 ) 2 , m.p. 143, formed on 
 heating diphenyl-urea or diphenyl-sulpho-urea, by itself, or with 
 copper, to 140, also by warming the alcoholic solution of diphenyl- 
 sulpho-urea and aniline with Pb(OH) 2 (C. 1902, II. 795) or HgO, or 
 by boiling it with iodine solution. CS 2 splits it up into diphenyl- 
 sulpho-urea and phenyl-mustard oil. 
 
 j8-Triphenyl-guanidin NH : c/^* 1 ^, m .p. 131, has been obtained 
 
 -^ Jriv^g Jri-c 
 
 by heating cyano-anilide with diphenyl-amine chlorohydrate. CS 2 
 breaks it up into diphenyl-amine, phenyl-mustard oil, and hydrogen 
 sulpho-cyanide. 
 
 Sym. Tetraphenyl-guanidin NH : C[N(C 6 H 5 ) 2 ] 2 , m.p. 130, by action 
 of CNC1 upon diphenyl-amine at 170. 
 
 as-Tetraphenyl-guanidin C 6 H 5 N : c/^ 1 ^? 2 , m.p. 140, and Penta- 
 
 \JNrlC 6 rl 5 
 
 phenyl-guanidin C 6 H 5 N : C[(NC 6 H 5 ) 2 ] 2 , m.p. 179, obtained by trans- 
 formation of aniline and diphenyl-amine, respectively, with triphenyl- 
 chloro-carbamidin (B. 36, 964). 
 
 Amido-diphenyl-guanidin C 6 H 5 N : C(NHC 6 H 5 )NH.NH 2 , m.p. 99, 
 formed from diphenyl-thio-urea with hydrazin hydrate in alcoholic 
 alkaline solution (without alkali, phenyl-thio-semicarbazide is formed) ; 
 it is a strong base. With anilines it gives addition products; with 
 carboxylic acids, and with HNO 2 , it condenses to triazol and tetrazol 
 derivatives respectively (B. 33, 1058 ; 35, 1710, 1716). 
 
 Diphenyl-oxyguanidin, oximido-diphenyl-urea HON : C(NHC 6 Hs) 2 , 
 m.p. 151, from diphenyl-thio-urea with alcoholic hydroxylamine 
 solution and PbO (B. 32, 2238). 
 
 PHENYL-BIGUANIDES. a-Phenyl-biguanide * ")C.NH.C<^ 
 
 JNrl 2 / \JNrlL/ 6 rl 5 
 
 chlorohydrate, m.p. 237, by heating aniline chlorohydrate with 
 dicyano-diamide (C. 1905, I. 730 ; II. 1530). a-Diphenyl-biguanide 
 
 / C - NH - C \NH<^H 5 ' m ' p ' l67 ' from sulpho-carbanilide and 
 guanidin (see A. 310, 335 ; B. 34, 2594). 
 
 G. Phenylated Nitriles and Imides of Carbonic Acid. 
 
 Phenyl isocyanate, carbanile C 6 H 5 N : CO, b.p. 166, a liquid with an 
 acrid odour, formed (i) by distillation of oxanilides ; (2) by distillation 
 of carbanilic esters with P 2 O 5 (B. 25, 2578) ; (3) from diazo-benzol 
 
NITRILES AND IMIDES OF CARBONIC ACID 105 
 
 salts by the action of potassium cyanate and copper (B. 25, 1086) ; 
 (4) from phenyl-mustard oil C (} H 5 .N : CS by heating with HgO to 170 
 (B. 23, 1536) ; (5) by the action of thionyl chloride upon benzo- 
 hydroxamic acid (q.v.) in benzene solution (C. 1907, I. 633) ; (6) by 
 warming benzoyl azide (q.v.) or benzoyl chloride and sodium azide, 
 in neutral solvents (B. 42, 3133, 3359) ; (7) by the action of HNO 2 
 upon monophenyl-urea, with excess of HC1 (C. 1906, II. 510) ; (8) by 
 action of phosgene upon aniline, or its chlorohydrate. By methods 
 6, 7, and 8 a series of substituted carbaniles could also be prepared 
 (C. 1900, I. 30 ; 1902, II. 554). 
 
 Carbanile behaves very similarly to the isocyanic alkyl esters. With 
 water it becomes diphenyl-urea, with alkalies it forms salts of phenyl- 
 carbaminic acid (/. pr. Ch. 2, 73, 177). With alcohols and phenols it 
 combines to form carbanilic esters, a reaction useful for proving the 
 presence of alcoholic hydroxyls (B. 18, 2428, 2606). It reacts similarly 
 with the SH group, and with the hydroxyl group of the aldoximes and 
 ketoximes. With the groups C : O and C : S carbanile does not react 
 (B. 25, 2578) ; but it unites with I, 3-dicarbonyl compounds, like 
 acetyl-acetone, aceto-acetic ester, malonic ester, etc., in the presence 
 of small quantities of alkali, to form C-carbanilide derivatives, e.g. 
 C 6 H 5 NHCOCH(COCH 3 )CO 2 R, which, in contrast with O-carbanilide 
 derivatives, have an acid nature and show the ferric chloride reaction 
 (B. 37, 4627). 
 
 With NH 3 we obtain phenyl-urea. With diazo-amido-compounds 
 C 6 H 5 N 2 NHR' mixed ureas are formed, in which the hydrogen of the 
 NH group is represented by the residue CONHC 6 H 5 (B. 22, 3109). 
 For action upon dicarboxylic acids, see C. 1906, I. 1017 ; upon oxy- 
 acids, C. 1903, I. 564. 
 
 All these phenyl-cyanate reactions, if taking place in the absence 
 of a solvent, usually take place normally without transpositions, and 
 are therefore suitable for determinations of constitution (B. 23, 2179 ; 
 38, 22). By heating of carbanile with benzene and A1 2 C1 6 , we obtain 
 benzoyl anilide (see synthesis of benzoic acid). 
 
 o-, m-, p-Tolyl isocyanate CH 3 C 6 H 4 N : CO, m.p. 186, 183, 187, 
 by method 7. 
 
 Triphenyl isocyanurate C 3 O 3 (NC 6 H 5 ) 3 , m.p. 275, formed (i) by 
 polymerisation of carbanile, on heating with potassium acetate (B. 
 18, 3225) ; (2) by the action of concentrated HC1 at 150 upon triphenyl- 
 iso-melamin. 
 
 Triphenyl cyanurate C 3 N 3 (OC 6 H 5 ) 3 , m.p. 224, by the action of 
 cyanic or cyanuric chloride upon sodium phenol. 
 
 Isocyano-phenyl chloride, phenyl-imido-carbonyl chloride C 6 H 5 N : 
 CC1 2 , b.p. 209, a colourless oil, of acrid odour, formed from phenyl 
 isocyanide and chlorine in chloroform solution ; also from phenyl- 
 mustard oil and chlorine (B. 26, 2870). With aniline it passes into 
 a-triphenyl-guanidin (A. 270, 282). 
 
 Phenyl sulpho-cyanide C 6 H 5 S.CN, b.p. 131, is isomeric with phenyl- 
 mustard oil and methenyl-amido-thio-phenol C 6 H 4 <^ S ^;CH (see Amido- 
 
 thio- phenols). Formed by action (i) of HSCN upon diazo-benzol 
 sulphate, and (2) of cyanogen chloride upon lead thio-phenol. It 
 behaves like the alkyl sulpho-cyanic esters. 
 
106 ORGANIC CHEMISTRY 
 
 Phenyl-mustard oil, sulpho-carbanile, iso-thio-cyanic phenyl ester 
 C 6 H 5 N : CS, b.p. 222, is a colourless liquid smelling of mustard oil. 
 Formed (i) from diphenyl-sulpho-urea by splitting off aniline with 
 hot sulphuric acid or concentrated HC1, or, best, with concentrated 
 phosphoric acid (B. 15, 986) ; (2) besides triphenyl-guanidin, from 
 diphenyl-sulpho-urea with alcoholic iodine solution ; (3) by action of 
 thio-phosgene upon aniline ; (4) by action of HNO 2 upon phenyl- 
 sulpho-urea (C. 1906, II. 510). 
 
 Heating with copper or zinc dust converts it into benzo-nitrile, 
 the phenol-iso-nitrile first formed transposing into benzo-nitrile at the 
 temperature of reaction. Heated with dry alcohols to 120, or in 
 alcoholic potash solution, it becomes phenyl-sulphur-ethane (C. 1900, 
 I. 289) ; with ammonia, aniline, hydrazin, or hydroxylamine it becomes 
 phenyl-sulpho-urea ; with chlorine, iso-cyano-phenyl chloride. With 
 sodium-malonic ester it combines to form thio-carbanilino-malonic 
 ester (C. 1908, I. 1929). Combines with aromatic hydrocarbons, 
 phenol ethers, and thio-phenol ethers under the influence of Al chloride 
 to thio-anilides of carboxylic acids (/. pr. Ch. 2, 59, 572). 
 
 With alkyl-magnesium iodides (Vol. I.), phenyl-mustard oil com- 
 bines to form salts which, on decomposition with acids, yield thio- 
 anilides of fatty acids, e.g. NH.CS.CH 3 (B. 36, 585). By reduction 
 with zinc and HC1, it is decomposed into aniline and thio-formaldehyde, 
 but by Al amalgam into sulpho-carbanilide and methyl mercaptan 
 (B. 34, 2033). 
 
 PHENYLATED CYANAMIDE DERIVATIVES (cp. Cyanamide, Vol. I.)- 
 Phenyl-cyanamide, cyananilide C 6 H 5 NHCN-f-JH 2 O, m.p. 47, loses 
 its water of crystallisation in the drying oven, liquefies, and re-forms 
 the hydrate in air. On standing, or heating, it polymerises to tri- 
 phenyl-iso-melamine. Formed (i) by conducting CNC1 into an ether 
 solution of aniline ; (2) by heating phenyl-sulpho-urea, with HgO or 
 lead acetate and alkali (B. 18, 3220). It is easily soluble in alcohol 
 and ether, and combines again with H 2 S to form phenyl-sulpho-urea. 
 For substituted cyananilides, see C. 1905, I. 441 ; 1907, I. 543. 
 
 Phenyl-methyl cyanamide C 6 H 5 N(CH 3 )CN, m.p. 30, from cyan- 
 anilide, ICH 3 and NaOC 2 H 5 (B. 33, 1383) ; or from mono-, or even 
 dimethyl-aniline, with CNBr. The latter process has yielded a number 
 of homologous phenyl-alkyl cyanamides (B. 33, 2728 ; 35, 1279). 
 
 Diphenyl cyanamide (C 6 H 5 ) 2 NCN, m.p. 73, from as-diphenyl-thio- 
 urea with ammonia, and silver solution (B. 26, R. 607). 
 
 Carbo-diphenyl-imide C 6 H 5 N : C : NC 6 H 5 , a thick liquid, b.p. 30 218. 
 On distillation, at ordinary pressures, carbo-diphenyl-imide transposes 
 into a polymeric modification melting at 161, and having triple 
 molecular weight (B. 28, 1004). 
 
 Carbo-diphenyl-imide is formed (i) by action of HgO upon a 
 solution of symmetrical diphenyl-sulpho-urea in benzene ; (2) by 
 distillation of a-triphenyl-guanidin ; (3) by heating phenyl isocyanate 
 to 180, with rejection of CO 2 (B. 41, 1125). With water it combines 
 to form a symmetrical diphenyl-urea ; with H 2 S, to a symmetrical 
 diphenyl-sulpho-urea ; with aniline, to a-triphenyl-guanidin ; with 
 phenol, to diphenyl-iso-urea phenyl ether (C. 1909, II. 426). On con- 
 ducting HC1 into a benzene solution of carbo-diphenyl-imide we 
 obtain the compounds C 6 H 5 N : CC1.NHC 6 H 5 and C 6 H 5 NH.CC1 2 .NHC 6 H 5 
 
ANILIDES OF DICARBOXYLIC ACIDS 107 
 
 (B. 28, R. 778) ; with malonic ester, and similar bodies, carbo-diphenyl- 
 imide forms substances like C 6 H 5 NH.C(NC 6 H 5 ).CH(CO 2 C 2 H 5 ) 2 (B. 32, 
 3176). It also combines with aliphatic and thio-aliphatic acids to 
 form compounds like acetyl-diphenyl-urea and acetyl-diphenyl-thio-urea 
 (J. pr. Ch. 2, 64, 261). 
 
 Alkyl-magnesium iodides give Mg compounds, which, with acids, 
 decompose into diphenyl-amidines. 
 
 Carbodi-p-tolyl-imide (C 7 H 7 N) 2 C, m.p. 57-59. 
 
 Triphenyl-melamine, triphenyl-cyanuro-triamide 
 
 r H N r /NH.C(NHC.H.K 
 C 6 H 5 N C > 
 
 m.p. 228, by the action of cyanuro-chloride upon aniline, or by heating 
 tri-thia-cyanuric methyl ester with aniline to 25O-30O (B. 18, 3218). 
 
 Hexaphenyl-melamine, C 3 N 3 [N(C 6 H 5 ) 2 ] 3 , m.p. 300, from cyanuric 
 chloride and diphenyl-amine. 
 
 Triphenyl-isomelamine NH 
 
 by polymerisation of phenyl cyanamide ; also by the action of 
 cyanogen bromide upon aniline. On heating with HC1 the NH groups 
 are successively replaced by oxygen, with final formation of isocyanuric 
 triphenyl ester. 
 
 Besides the normal and iso-triphenyl-melamines, unsymmetrical 
 triphenyl-melamines are also known (B. 18, 228). 
 
 ANILIDES OF DICARBOXYLIC ACIDS. Oxalic acid and its homo- 
 logues, as well as the unsaturated dicarboxylic acids, form anilic acids 
 and dianilides, corresponding to the amino-acids and the diamides. 
 Those dicarboxylic acids capable of forming anhydrides yield also 
 aniles or phenyl-imides corresponding to the imides. 
 
 The anilic acids are obtained (i) by partial decomposition of the 
 dianilides ; (2) on mixing the ethereal or chloroform solutions of the 
 anhydrides with aniline (B. 20, 3214) ; (3) by the breaking down of 
 the aniles. The latter are re-formed from the anilides by treatment 
 with PC1 5 (B. 21, 957), or with acetyl chloride. They also appear 
 on heating the acids or anhydrides with aniline. A large number of 
 these compounds have been mentioned in the first volume, in connection 
 with their respective acids. 
 
 PHENYL-AMINE DERIVATIVES OF OXALIC ACID. Oxanilic acid C 6 H 5 
 NH.CO.CO 2 H, m.p. 150 (see A. 270, 295, for an isomeric acid, m.p. 
 210), is formed by heating oxalic acid and aniline to 140 (B. 23, 
 1820), by the action of alcoholic potash upon oxanilide, and when 
 citracon-anilic acid is oxidised with MnO 4 K (B. 23, 747). Methyl 
 ester, m.p. 114 (A. 254, 10) ; ethyl ester, 66 ; chloride, 82 (B. 23, 
 1823). 
 
 Oxanilic acid nitrile, cyano-formanilide C 6 H 5 NHCOCN, m.p. 120, 
 prepared by adding hydrocyanic acid to phenyl isocyanate. On 
 heating above its m.p. it decomposes into its constituents. On careful 
 saponification it passes into phenyl-oxamide C 6 H 5 NHCOCONH 2 , 
 m.p. 224 ; by addition of H 2 S it becomes oxanilic acid thio-amide 
 C 6 H 5 NHCOCSNH 2 , m.p. 176 (B. 38, 2977). 
 
 Oxanilide (CONHC 6 H 5 ) 2 , m.p. 245, is also obtained from the 
 
 isomeric glyoxime-N-phenyl-ether c 6 H 6 Nc >CH CH<- /NC 6 H 5) m.p. 
 
 \CK XX 
 
io8 ORGANIC CHEMISTRY 
 
 183, by transformation with glacial acetic acid and acetic anhydride. 
 The latter is formed (i) from nitroso-benzol with diazo-methane ; 
 (2) from j8-phenyl-hydroxylamine with glyoxal or with formaldehyde 
 (B. 30, 2871 ; 35, 1833). 
 
 A number of sulphuretted derivatives of oxanilic acid are obtained 
 by action of P 2 S 5 upon the corresponding compounds of oxalic acid. 
 They are distinguished by their intense yellow or reddish-yellow 
 colour (B. 37, 3708). 
 
 Thio-oxanilic acid C 6 H 5 NHCSCOOH, m.p. 102. Thio-oxanilide 
 C 6 H 5 NHCS.CONHC 6 H 5 , m.p. 145. Both compounds are easily 
 converted into derivatives of benzo-thiazol (q.v.). 
 
 Thio-oxanilic thio-amide C 6 H 5 NHCS.CSNH 2 , m.p. 98. 
 
 Dithio-oxanilide (CSNHC 6 H 5 ) 2 , m.p. 134, is also generated by the 
 action of H 2 S upon oxanilide chloride (C. 1902, II. 121). 
 
 Tetra-p-tolyl-oxamide [CON[4](C 6 H 4 [i]CH 3 ) 2 ] 2 , m.p. 127, from 
 p-ditolyl-urea chloride. 
 
 Oxanilide dioxime [C : (NOH)(NHC 6 H 5 )] 2 , m.p. 215 with decom- 
 position, from dibromo-glyoxime peroxide. Semi-ortho-oxalic-dianilido- 
 methyl ester CO 2 CH 3 .C(NHC 6 H 5 ] 2 OCH 3 , and Phenyl-imido-oxalie 
 dimethyl ester CO 2 CH 3 C iNCgHgfOCHg), m.p. 111, from dichlor-oxalic 
 ester (B. 28, 60) and aniline. Phenyl-oxaminic diphenyl-amidine 
 
 C 6 H 6 NHCO.C^^?J H5 , m.p. 134, from semi-ortho-oxalic ester and 
 
 vWCxjtlg 
 
 from oxanile dichloride acid ethyl ester (A. 184, 268). 
 
 The corresponding nitrile, carbo - diphenyl - imide - hydrocyanide, 
 NC.C(NHC 6 H 5 ) : NC 6 H 5 , generated from carbo-diphenyl-imide by union 
 with hydrocyanic acid, yields, with yellow Am 2 S, a thiamide NH 2 CS. 
 C(NHC 6 H 5 ) : NC 6 H 5 , which can be easily converted into isatin anilide 
 and indigo. 
 
 o-Nitro-oxanilic acid, m.p. 112. 
 
 o-Dinitro-oxanilide, see A. 209, 369. 
 
 Malon-anilic acid C 6 H 5 NHCOCH 2 CO 2 H melts at 132, with 
 decomposition into CO 2 and acetanilide. It is also formed by a 
 peculiar transposition of sodium acetyl-phenyl-carbaminate from 
 sodium acetanilide with CO 2 , on heating to 140 (B. 18, 1359). 
 With PC1 5 it forms trichloro-quinolin (B. 18, 2975). 
 
 Malon-anilide CH 2 (CONHC 6 H 5 ) 2 , m.p. 223 (B. 17, 135, 235). 
 Malonic methyl-anilide (B. 31, 1826). Dithio-malon-anilide CH 2 
 (CSNHC 6 H 5 ) 2 , m.p. 149, from malon-anilide, with P 2 S 5 (B. 39, 3300). 
 
 Succin-anilic acid, succin-anile, see Vol. I. : Succinimide. 
 
 Fumar-anilic acid, fumar-anilic chloride, fumaric dianilide, malein- 
 anilic acid, malein-anile, dichloro-malein-anile, dichloro-malein-anile 
 dichloride, dichloro-malein - anile - dimethyl ester, dichloro - malein- 
 imidanile, diehloro-malein-dianile, citracon-anilic acid, citracon-anile, 
 itacon-anilic acid, see Vol. I. in connection with the corresponding 
 carboxylic acids. 
 
 ANILIDO - CARBOXYLIC ACIDS. Anilido - malonic acid C 6 H 5 NH. 
 CH(COOH) 2 melts at 119, with rejection of CO 2 , and formation of 
 phenyl-glycin. Its esters (methyl, m.p. 68 ; ethyl, m.p. 45) are 
 formed from the bromo-malonic esters, with aniline, and behave like 
 malonic esters in having their C atom alkylated, and in forming 
 addition products with a, j8-olefin-carboxylic ester, etc. (see Vol. I.). 
 
ANILINE HALOIDS 109 
 
 On heating to 26o-265 they condense to indoxyl-acetic esters, 
 which can easily be converted into indigo (B. 35, 54). For the effect 
 of nitrous acid, see C. 1902, II. 1318. 
 
 For phenyl-asparagin-anilic acid, phenyl-asparagin-anile, 3-anilido- 
 pyro-tartaric acid, and pseudo-itaeon-anilic acid, see Amido-succinic 
 acids, Vol. I. 
 
 PHENYLATED UREIDS OF DICARBOXYLIC ACIDS. Phenyl-parabanic 
 
 acid co<^: 6H5) ~9?, m.p. 208, and diphenyl-parabanic acid, m.p. 
 
 \ JN xd. ...... x>vJ 
 
 204, from the corresponding carbamides with ethoxalic chloride 
 (/. pr. Ch. 2, 32, 20). 
 
 m.p. 238, formed by the action of malonyl chloride upon carbanilide. 
 
 As uric acid is obtained from malonyl-urea (Vol. I.), so from 
 diphenyl-malonyl-urea, through the intermediacy of diphenyl-violuric 
 acid, m.p. 227, we obtain diphenyl-uramile, m.p. 195; diphenyl- 
 j/r-uric acid, m.p. 217 ; and 1, 3-diphenyl-uric acid, m.p. above 300 
 (C. 1907, II. 1065). 
 
 ANILINE SUBSTITUTION PRODUCTS. It is only the aniline derivatives, 
 among the substitution products of the primary phenyl-amines, which 
 deserve particular consideration, for it was with them that the re- 
 gularities of substitution obtaining among the aromatic amido-bodies 
 were observed, and they were the intermediate stages in numerous 
 instances where constitution was to be determined. 
 
 ANILINE HALOIDS. Formation : (i) Aniline, like phenol, is more 
 readily substituted than benzene. When chlorine or bromine acts 
 upon the aqueous solutions of aniline salts, the halogen atoms enter 
 the [2, 4, 6]-position. Concerning the additive intermediate products 
 preceding substitution, see A. 346, 128 ; B. 38, 2159. Starting with 
 acetanilide, chlorine and bromine produce first p- and o-mono-sub- 
 stitution products; these are immediately converted into o-p-di-sub- 
 stitution derivatives. If, however, chlorine or bromine be allowed 
 to act upon aniline, in the presence of concentrated sulphuric or hydro- 
 chloric acid, m-compounds will be produced. By combining with the 
 strong acids the amido-group acquires a negative character. Con- 
 cerning further substitutions in meta-substituted anilines, see B. 15, 
 1328 ; C. 1899, II. 1049. 
 
 Iodine can substitute the anilines directly ; the resulting hydriodic 
 acid combines with the excess of base : 
 
 2C 6 H 6 .NH a +I 2 =C 6 H 4 LNH I +C,H 5 .NH a .HI. 
 
 (2) The mono-halogen anilines can be readily obtained from the 
 mono-halogen-nitro-benzols, which in turn are derived from the 
 nitro-amido-derivatives. The change is effected through the diazo- 
 bodies. 
 
 p-Chloraniline is a stronger base than the o- and m-bodies 
 (B. 10, 974). It has also been obtained by the electrolytic re- 
 duction of nitro-benzol in concentrated hydrochloric acid solution. 
 It is very probable that C 6 H 5 .NHC1 is formed at first, but sub- 
 sequently rearranges itself into p-chloraniline (B. 29, 1895 ; C. 1904, 
 
 n. 95). 
 
no 
 
 ORGANIC CHEMISTRY 
 
 
 [I. 2]-, 0- 
 
 [i. 3]-, m- 
 
 [i, 4l-. P- 
 
 
 
 M.p. 
 
 B.p. 
 
 M.p. | B.p. 
 
 M.p. | B.p. 
 
 
 F1C 6 H 4 NH_ 
 
 
 
 
 
 liquid 
 
 188 
 
 (A. 243, 222) 
 
 C1C 6 H 4 NH 2 
 
 liquid 
 
 207 
 
 liquid 
 
 230 
 
 ?o 
 
 230 
 
 (A. 176, 27) 
 
 BrC 6 H 4 NH 2 
 
 3i 
 
 22 9 
 
 18 
 
 251 
 
 66 
 
 . . 
 
 (B. 8, 364) 
 
 IC 6 H 4 NH 2 
 
 56 
 
 
 27 
 
 
 63 
 
 
 
 (B. 17, 487) 
 
 Of the higher halogen substitution products of aniline we may 
 mention the following : 
 
 From acetanilide : 
 
 a-[i NH 2 , 2, 4]-Dichloraniline, m.p. 63, b.p. 245 (B. 7, 1602). 
 a-[i NH 2 , 2, 4]-Dibromaniline, m.p. 79 (A. 121, 266). 
 
 From the nitro-compounds : 
 
 jS-[i,4,2NH 2 ]-Dichlorannine, m.p. 54, b.p. 250 (A. 196, 215). 
 j3-[i,4,2NH 2 ]-Dibromaniline, m.p. 51 (A. 165, 180). 
 
 [i NH 2 , 2, 6]-Di-iodaniline, m.p. 122 (C. 1904, II. 319). 
 
 [i NH 2 , 2, 4]-Di-iodaniline, m.p. 96 (C. 1904, II. 590). 
 
 From aniline with Cl and Br : 
 
 [iNH 2 ,2, 4, 6]-Trichloraniline, m.p. 77, b.p. 262 (/. pr. Ch. 2, 
 
 16, 449 ; B. 27, 3151). 
 
 [i NH 2 , 2, 4, 6]-Tribromaniline, m.p. 119 (B. 16, 635). 
 [iNH 2 , 3,4, 5]-Tribromaniline, m.p. ii8-ii9 (C. 1898, I. 939). 
 [iNH 2 ,2,4,6]-Tri-iodaniline, m.p. 184 (C. 1910, I. 526). 
 
 The five benzene-hydrogen atoms in aniline can be replaced by 
 chlorine or bromine : 
 
 Penta-ehloraniline, m.p. 232. Penta-bromaniline, m.p. 222. 
 Halogen benzols are produced by eliminating the amido-group by 
 means of the diazo-compounds. 
 
 For di-, tri-, and tetra-iodanilines and their transformation products, 
 see B. 34, 3343. 
 
 For further aniline haloids, see C. 1907, II. 1784 ; A. 346, 160. 
 
 NITRANILINES NO 2 C 6 H 4 NH 2 are isomeric with diazo-benzolic acid 
 C 6 H 5 NHNO 2 . Aniline is strongly attacked by nitric acid, and easily 
 resinified. (i) In order to obtain mono- and di-substitution products, 
 acetanilide is nitrated. The acetyl group protects the amido-group, 
 and p- and o-nitro-acetanilide are first formed, with an excess of nitric 
 acid, chiefly the p-compound ; while with the calculated amount of 
 HNO 3 , in glacial acetic acid with addition of acetic anhydride, we 
 obtain chiefly the o-nitro-acetanilide (B. 39, 3903) But if aniline is 
 nitrogenated in the presence of cold concentrated sulphuric acid, meta- 
 nitraniline is also formed, besides the p- and o- varieties (B. 10, 1716 ; 
 17, 261), and its amount increases with the quantity of sulphuric acid 
 present. There is here the linking of an amido-group and, so to speak, 
 transformation into an acid group, which produces meta-substitution. 
 The three isomers are separated by their basicities. On neutralising 
 their acid solutions, o-nitraniline precipitates, first o-, then p-, and then 
 
NITRANILINES in 
 
 m-nitraniline (B. 28, 1954). In a similar manner the nitroacetanilides 
 can be separated (B. 39, 3903). 
 
 (2) The nitranilines can also be obtained by heating the nitro- 
 benzol haloids to I5o-i8o with alcoholic ammonia ; also by heating 
 the nitre-phenol ethers, like C 6 H 4 (NO 2 ).O.C 2 H 5 , with aqueous am- 
 monia. In both cases it is only the para- and or^o-derivatives which 
 react, but not the w^a-derivatives. 
 
 (3) The direct introduction of an amido-group into the o- or p- 
 position, with respect to the nitro-groups present, may be effected by 
 the action of an alcohol-alkaline hydroxylamine solution. 
 
 (4) By partial reduction of poly-nitro-compounds. 
 
 (5) By heating nitro-amido-benzol-sulphonic acids with HC1 to 
 170 (B. 18, 294 ; C. 1905, I. 416). 
 
 (6) o- and p-nitraniline are produced by transposition of diazo- 
 benzolic acid : 
 
 [i, 2]-, o-Nitraniline, m.p. 71 ; Acet. m.p. 92. o-Nitro- 
 
 dimethyl-aniline, see B. 32, 1066. 
 [i, 3]-, m-Nitraniline, m.p. 114 ; Acet. m.p. 142. 
 [i, 4]-, p-Nitraniline, m.p. 147 ; m.p. 207. 
 
 The nitro-anilmes link the diamido- and dinitro-benzols to the 
 nitro-haloid, amido-haloid, and dihaloid benzols : 
 
 NH. r /NO. r w /NO. p /NO. r /NH. r /Br 
 - ~ 
 
 When ortho- and^ara-nitranilines (not meta-) are boiled with alkalies, 
 they part with NH 3 , and are converted into their corresponding nitro- 
 phenols C 6 H 4 (NO 2 ).OH ; the di- and tri-nitranilines react even more 
 readily. 
 
 The nitranilines approach in character the acid amides as the number 
 of nitro-groups in them increases. 
 
 Ammonia converts the corresponding dinitro-phenols or poly- 
 nitro-haloid-benzols into : 
 
 a-[i NH 2 ,2, 4]-Dinitraniline, m.p. 182. 0-[i NH 2 , 2, 6]-DinitranUine, 
 m.p. 138. 
 
 [i NH 2 ,2, 4, 6]-Trinitraniline C 6 H 2 (NO 2 ) 3 .NH 2 , picramide, is obtained 
 from picric acid through its ether, or by means of picryl chloride. 
 The latter reacts with ammonia, even in the cold. It forms orange-red 
 needles, m.p. 186. It forms picric acid when heated with alkalies : 
 
 C 6 H 2 (N0 2 ) 3 .NH 2 +KOH=C 6 H 2 (N0 2 ) 3 .OK+NH 3 . 
 
 Sym. Trinitro-xylidine, m.p. 206, from trinitro-chloro-xylol and NH 3 
 (B. 28, 2047). 
 
 NITRO-DIPHENYL-AMINES are obtained by the transformation of 
 benzol-nitro-haloids with aniline, or of the nitranilines with bromo- 
 benzols and addition of copper bronze or copper iodide. o-Nitro- 
 bromo-benzol and the polynitro-halogen-benzols react with aniline 
 even without a catalyst. In a similar manner the aryl-sulphonic 
 esters of o-nitro-phenol, and its derivatives, yield nitro-diphenyl- 
 amines with aniline (B. 41, 1870). Numerous nitro-diphenyl-amines 
 have also been obtained by nitrogenating nitroso- or benzoyl-diphenyl- 
 
ii2 ORGANIC CHEMISTRY 
 
 amine, and breaking up the resulting compounds with dilute SO 4 H 2 
 (C. 1906, I. 28). 
 
 The nitro-diphenyl-amines are pale -yellow compounds. They 
 yield dark-red alkali salts, with a stability increasing with the number 
 of nitro-groups they contain. 
 
 Hexanitro-diphenyl-amine dissolves in aqueous alkalies, with a 
 purple colour. Its ammonium salt is a brick-red powder. Before 
 the introduction of the azo-dyes, it was used under the name of 
 " aurantia " for dyeing wool and silk. At present it is only used for 
 making photographic colour-filters. The corresponding salt of penta- 
 nitro-diphenyl-amines possesses no dyeing power. 
 
 These strongly coloured alkali salts probably possess a quinoid 
 structure : 
 
 The nitro-diphenyl-amines probably therefore belong to the class 
 of pseudo-acids (Vol. I.). They form two series of alkyl derivatives : 
 pale-yellow, stable nitrogen ethers corresponding to the free nitro- 
 phenyl-amines ; and dark-violet, unstable oxygen esters corresponding 
 to the dark-coloured alkali salts, and possessing, like the latter, a 
 quinoid structure (aci-nitro-derivatives) : 
 
 I. (N0 2 ) 3 C 6 H 2 .N(CH 3 )C 6 H 2 (N0 2 ) 3 II. (NO 2 ) 3 C 6 H 2 N : C 6 H 2 (NO 2 ) 2 : NOOCH 3 
 
 Pale yellow. Deep violet. 
 
 o-, m-, and p-Nitro-diphenyl-amine NO 2 C 6 H 4 NHC 6 H 5 , m.p. 75, 
 112, 132 (B. 15, 826 ; 22, 903 ; 40, 4545). 
 
 o, o-, p, p-, and o, p-Dinitro-diphenyl-amine N0 2 C 6 H 4 NHC 6 H 4 NO 2 , 
 m.p. 167, 214, 219 (B. 15, 826). 
 
 [2, 4, 6] - Trinitro - phenyl - phenyl - amine, m.p. 175, from picryl 
 chloride (B. 3, 126). Trinitro-xylyl-phenyl-amine, m.p. 175 (B. 28, 
 2047). Similar compounds, see B. 33, 594 ; C. 1898, II. 342. 
 
 Pentanitro-diphenyl-amine, m.p. 194. Hexanitro-diphenyl-amine, 
 m.p. 238. 
 
 N-Methyl-2,4-dinitro-diphenyl-amine C 6 H 5 N(CH 3 )C 6 H 3 (NO 2 ) 2 , m.p. 
 167, from i, 2, 4-chloro-dinitro-benzol and methyl- aniline, gives, on 
 further nitrogenation, N - methyl - hexanitro - diphenyl - amine, m.p. 
 236, yellow flakes. The isomeric o-methyl-aci-hexamtro-diphenyl- 
 amine, in violet-black crystals decomposing at 141, is obtained by 
 the action of ICH 2 upon the silver salt of hexanitro-diphenyl-amine. 
 Traces of alcoholic HC1 rapidly saponify the ester. But acetyl chloride 
 gives, with the silver salt, an N-acetyl-hexanitro-diphenyl-amine, pale- 
 yellow crystals melting at 240 (B. 41, 1745). 
 
 p-Nitro-phenyl-amine NO 2 C 6 H 4 N(C 6 H 5 ) 2 , m.p. 144, from p-nitro- 
 iodo-benzol and diphenyl-amine, in presence of copper bronze (B. 41, 
 35n). 
 
 H. p-NlTROSO-DERIVATIVES OF THE PRIMARY, SECONDARY, 
 AND TERTIARY AROMATIC AMINES. 
 
 Formation. (i) When the nitrosamines of monomethyl-aniline 
 or diphenyl-amine are treated with alcoholic hydrochloric acid, they 
 rearrange themselves into p-nitroso-compounds (B. 19, 2991). (2) 
 The p-nitroso-bodies are also produced when nitrous acid acts upon 
 
p-NITROSO-DERIVATIVES OF AROMATIC AMINES 113 
 
 the tertiary dialkyl-anilines, or sodium nitrite upon their hydro- 
 chlorides (Baeyer and Caro, B. 7, 963). (3) When the nitroso-phenols 
 are fused with ammonium acetate and ammonium chloride, they yield 
 p-nitroso-anilines (B. 21, 729). 
 
 Behaviour. When the p-nitroso-derivatives of the secondary and 
 tertiary aromatic amines are heated with caustic soda, they break 
 down into sodium nitroso-phenate and alkylamines (I. 163). Most 
 chemists consider the nitroso-phenols to be the monoximes of the 
 paraquinones. And in connection with this mode of formulation 
 of the nitroso-phenols, many are disposed to view the p-nitroso- 
 derivatives, of the secondary and tertiary aromatic amines, as quinine 
 derivatives : 
 
 r[i] : O r[i] : N.OH |[i] : N = (CH 3 ) 2 
 
 C M[ 4 ]:0 C 'M[ 4 ]:0 C H *i[ 4 ]:N>0 
 
 p-Quinine. p-Quinone-monoxime p-Nitroso-dimethyl-aniline. 
 
 Nitroso-phenol . 
 
 p-Nitroso-aniline NO[4]C 6 H 4 [i]NH 2 , m.p. 174, crystallises in 
 steel-blue needles (B. 21, 729 ; 28, R. 735). 
 
 p-Nitroso-monomethyl-aniline NO[4]C 6 H 4 [i]NHCH 3 forms blue 
 lustrous flakes, and melts at 118 C. It is soluble in dilute sodium 
 hydroxide, and is again liberated from its solution by carbon dioxide. 
 
 When heated with sodium hydroxide, p-nitroso-methyl-aniline is 
 decomposed into sodium nitroso-phenate and methyl-aniline. 
 
 p-Nitroso-monoethyl-aniline, m.p. 78. 
 
 o-, m-, and p-Nitroso-acetanilide NOC 6 H 4 NHCOCH 3 , m.p. 107, 
 ni, 173, by oxidation of the three mono-acetyl-phenylene-diamines 
 with monopersulphonic acid. The p-nitroso-acetanilide exists in a 
 grey and a colourless modification, m.p. 173 and 181 (C. 1908, 
 I. 2027). 
 
 p-Nitroso-dimethyl-aniline NO[4]C 6 H 4 [i]N(CH 3 ) 2 , m.p. 85, con- 
 sists of large green flakes. Potassium permanganate and ferro- 
 cyanide of potassium oxidise it to p-nitro-dimethyl-aniline. Upon 
 reduction it yields p-amido-dimethyl-aniline, which is so important 
 in the dye manufacture. Sodium hydroxide resolves it into nitroso- 
 phenol and dimethyl-aniline. Its hydrochloride dissolves with diffi- 
 culty in cold water. 
 
 p-Nitroso-diethyl-aniline, m.p. 84. 
 
 p-Nitroso-diphenyl-amine, m.p. 143, consists of green plates, and 
 is produced when hydrochloric acid gas acts upon diphenyl-nitros- 
 amine. Dissolves in concentrated aqueous alkalies with formation 
 of dark-brown alkali salts, derivable from the anile of quinone-mon- 
 oxime C 6 H 5 N : C 6 H 4 : NOH (B. 20, 1252 ; 21, R. 227). 
 
 5#. Diamines. 
 
 Formation. The aromatic diamines, whose amido-groups are 
 attached to the benzene nucleus, are formed (i) by the reduction of 
 the three dinitro-benzols or nitro-anilines with tin and hydrochloric 
 acid ; (2) the monamines can be converted into the diamines by first 
 changing them to amido-azo-compounds, and then decomposing the 
 latter by reduction : 
 
 C G H 5 N^N[ 4 ]C 6 H 4 [i]NH 2 + 4 H=C 6 H 5 NH 2 +NH 2 [ 4 ]C 6 H 4 [i]NH 2 . 
 
 VOL. II. I 
 
ii 4 ORGANIC CHEMISTRY 
 
 (3) They can be obtained, also, from the diamido-benzoic acids, by 
 the loss of carbon dioxide, when they are treated with baryta. This 
 reaction has become of particular importance in ascertaining the con- 
 stitution of the three phenylene-diamines. (4) Phenylated diamido- 
 benzols are formed by the semidin transposition of hydrazo-benzols ; 
 thus, o-amido-ditolyl-amine is formed from hydrazo-toluol. (5) Di- 
 phenylated diamido-benzols C 6 H 4 (NH.C 6 H 5 ) 2 are produced when dioxy- 
 benzols e.g. resorcinol and hydroquinone are treated with aniline 
 and CaCl 2 or ZnCl 2 . 
 
 Properties. The diamines are colourless solids volatilising without 
 decomposition, but on exposure to the air they become coloured. 
 They are di-acid bases, forming well-defined salts. Ferric chloride 
 imparts an intense red colour to their solution. The amide hydrogen 
 atoms can be replaced in the same manner as in the mon amines. 
 
 Diamido-benzols, or phenylene-diamines, C 6 H 4 (NH 2 ) 2 . The o-body 
 is derived from o-nitraniline by reduction with caustic soda and zinc 
 dust (B. 28, 2947). The m-derivative is most easily accessible through 
 m-dinitro-benzol. The p-compound is obtained by the decomposition 
 of amido-azo-benzol, or by heating p-dichloro-benzol with NH 3 in 
 presence of copper sulphate (Z.f. Ch. 1866, 136 ; C. 1908, II. 1221). 
 
 [i, 2]-, o-Phenylene-diamine, m.p. 102, b.p. 252 
 [i, 3]-, m-Phenylene-diamine, ,, 63, ,, 267 
 [i, 4]-, p-Phenylene-diamine, ,, 147, ,, 267. 
 
 o-Phenylene-diamine is coloured red, in hydrochloric acid solution, 
 by ferric chloride, with the production of diamido-phenazine hydro- 
 chloride (B. 27, 2782). Oxidation with PCO 2 or Ag 2 gives o-quinone- 
 di-imine, which immediately polymerises to O 2 -diamido-benzol. In 
 the table (see below), showing the numerous o-condensations of which 
 the o-diamines are capable, it is o-phenylene-diamine which appears 
 most frequently as the example. 
 
 o-Amido-phenyl-urethane melts at 86. 
 
 o-Amido-diphenyl-aniline, b.p. 217 (B. 32, 1903). 4, 6-Dinitro- 
 o-phenylene-diamine, m.p. 215, deep-red needles, by reduction of 
 picramide with alcoholic Am 2 S (B. 41, 3093). 
 
 m-Phenylene-diamine with nitrous acid becomes triamido-diazo- 
 benzol, or Bismarck brown. It imparts an intense yellow colour to 
 a very dilute solution of nitrous acid, and can therefore be used for the 
 colorimetric estimation of the latter in water (B. 14, 1015) ; if the 
 nitrite solution is allowed to flow quickly into the hydrochloric solu- 
 tion of the m-phenylene-diamine, we obtain, besides Bismarck brown, 
 1, 2, 4-Nitroso-m-phenylene-diamine NOC 6 H 3 (NH 2 ) 2 , garnet-red flakes 
 of m.p. 210 (B. 37, 2276). Concerning the action of COC1 2 , CS 2 , and 
 oxalic ester, cp. B. 7, 1263 ; 21, R. 521 ; 24, 2113 ; 36, 411. 
 
 Tetramethyl-m-phenylene-diamine, b.p. 267 (B. 36,3110). Tetra- 
 phenyl-phenylene-diamines C 6 H 4 [N(C 6 H 5 ) 2 ] 2 are produced from the 
 dichloro-benzols by heating with potassium diphenyl-amine (B. 32, 
 1912). m-Phenylene-carbyl-amine C 6 H 4 [i, 3](N : C) 2 is transposed 
 to isophthalic nitrile by heating (C. 1902, I. 463). 
 
 o-Nitro- and o-Amido-phenyl-m-phenylene-diamine NH 2 [2]C 6 H 4 . 
 NH.C 6 H 4 [3]NH 2 , see B. 34, 3089. 4-Nitro-m-phenylene-diamine, see 
 
DIAMINES 115 
 
 C. 1906, I. 517. 2, 4-Dinitro-m-phenylene-diamine, m.p. 254 (B. 39, 
 
 2538). 
 
 p-Phenylene-diamine oxidises in air to the dark garnet-red crystals 
 
 of Tetra-amido-diphenyl-p-azo-phenylene CA 
 
 m.p. 231 with decomposition (B. 27, 480). By Ag 2 O it is turned 
 into quinone di-imine (q.v.), by MnO 2 and sulphuric acid into quinone 
 (q.v.), by chloride of lime into quinone dichlorimine (q.v.). 
 
 p-Amido-dimethyl-aniline NH 2 [4]C 6 H 4 [i]N(CH 3 ) 2 , m.p. 41, b.p. 
 257, is obtained by reduction of p-nitroso- or p-nitro-dimethyl-aniline, 
 or by splitting up helianthin or p-dimethyl-amido-azo-benzol (B. 16, 
 2235) . In acid solution it gives with SH 2 and ferric chloride a dark-blue 
 colour methylene blue (q.v.) and therefore is used as a sensitive reagent 
 for SH 2 . N, N^dimethyl-p-phenylene-diamine CH 3 NH[i]C 6 H 4 [4] 
 NHCH 3 , m.p. 53, b.p. 17 150, is oxidised by Ag 2 O to quinone dimethyl- 
 imine (B. 38, 2248). 
 
 Thionyl- and formyl-p-amido-dimethyl-aniline, see B. 27, 602 ; 
 31, 2179. p-Phenylene-dicarbyl-amine (CJHJfi^JfN : C), yields, on 
 heating, terephthalic acid nitrile (C. 1902, I. 463). Nitro-p-phenylene- 
 diamine, m.p. 135, lustrous green needles, from [i, 2, 4]-dinitraniline 
 (B. 28, 1707 ; 29, 2284). 
 
 DIAMIDO-TOLUOLS, ToLUYLENE-DiAMiNES. All the six isomers 
 predicted by theory are known : 
 
 1. [i CH 3 , 2, 3]-Toluylene-diamine, m.p. 61, b.p. 255 (A. 228,243) 
 
 2. [i CH 3 , 3, 4]-Toluylene-diamine, 88, 265 
 
 3. [i CH 3 , 2, 4]-Toluylene-diamine, 99, 280 
 
 4. [i CH 3 , 2, 6]-Toluylene-diamine, 103, (B. 17, 1959) 
 
 5. [i CH 3 , 3, 5]-Toluylene-diamine, liquid, 284 (A. 217, 200) 
 
 6. [i CH 3 , 2, 5]-Toluylene-diamine, m.p. 64, 273. 
 
 [1, 3, 4]-Toluylene-diamine is the most accessible o-diamine. It is 
 prepared from p-aceto-toluidin : 
 
 , rilCH r[i]CH s r[i]CH 3 f[i]CH 3 
 
 C H < u NH COCH >C * H *\ [3 J NO * >C 6 H 3 | [3JNO, *C,HJ [ 3 ]NH, 
 
 ' Ha l[ 4 ]NHCOCH 3 l[ 4 ]NH, l[ 4 ]NH a 
 
 1, 2, 4-Toluylene-diamine is the fundamental body for the prepara- 
 tion of toluylene red (q.v.). 
 
 Xylylene-diamine. The eleven theoretically possible diamido-xylols 
 have all been obtained, and four of them are derivable from o-phenylene- 
 diamine: (NH 2 ) 2 [i, 2](CH 3 ) 2 [ 3 , 4], m.p. 89; -[4,5]-, m.p. 126; 
 -[3, 5]-, m.p. 78 ; -[3, 6]-, m.p. 75. 
 
 Four derivatives from m-phenylene-diamine : (NH 2 ) 2 [i,3](CH 3 ) 2 
 [4, 5]-, m.p. 67 ; -[2, 4]-, m.p. 66 ; -[4, 6]-, m.p. 105 ; -[2, 5]-, m.p. 
 103; and 
 
 Three derivatives from p-phenylene-diamine : (NH 2 ) 2 [i, 4](CH 3 ) 2 
 [2, 3]-, m.p. 116; -[2, 6]-, m.p. 104; -[2, 5]-, m.p. 150 (B. 35, 636). 
 
 [1, 2, 3, 5, 6]-o-Diamido-pseudo-cumol, m.p. 90 ; p-Diamido-pseudo- 
 cumol, m.p. 78 (B. 24, 1647). Diamido-mesitylene, m.p. 90 (A. 141, 
 134 ; 179, 176, etc.). 
 
 In the phenylene-diamines with a methylated nucleus, the amidyl in 
 para-position to a methyl is more easily acidulated than the o- and 
 m-position amidyls (B. 35, 681). Concerning the influence of nucleus- 
 
n6 ORGANIC CHEMISTRY 
 
 alkylene upon the alkylation of the phenylene-diamines at the 
 nitrogen, see C. 1902, I. 1279. 
 
 p-Amido-diphenyl-amine NH 2 [4]C 6 H 4 [i]NHC 6 H 5 , m.p. 75, by 
 reduction of p-nitroso-diphenyl-amine with (NH 4 ) 2 S. It also forms 
 during the electrolytic reduction of nitro-benzol in hydrofluosilicic acid 
 solution. Ferric chloride oxidises it to emeraldin (q.v.) (B. 40, 289). 
 
 p 2 -Diamido-diphenyl-amine, m.p. 158, by semidin-transposition of 
 p-amido-hydrazo-benzol (C. 1906, I. 232). 
 
 p-Amido-triphenyl-amine NH 2 [4]C 6 H 4 [i]N(C 6 H 5 ) 2 , m.p. i45-i48, 
 by reduction of the corresponding nitro-compound. A p-Chloranilino- 
 triphenyl-amine, m.p. 77-8i, is formed by a complex reaction in the 
 breaking up of tetraphenyl-hydrazin with HC1 (B. 41, 3507). 
 
 THE CONDENSATIONS OF THE O-DIAMINES. 
 
 The o-diamines possess the power in a remarkable degree of forming 
 condensation products. These usually consist of ring-systems con- 
 taining five or six atoms, and will be discussed in connection with the 
 heterocyclic carbon derivatives. The m- and p-diamines do not 
 possess this power. The condensation occurs in that hydrogen atoms 
 of both amido-groups of an o-diamine are replaced by polyvalent 
 atomic groups. Frequently, when this occurs, the nitrogen atoms 
 occupying the o-position unite with one another. 
 
 1. Sulphur dioxide and selenium dioxide convert the o-diamines 
 into piazo-thiols (q.v.) and piazo-selenols (q.v.). 
 
 2. Nitrous acid produces azimides (q.v.). 
 
 3. The cyclic amidines are directly produced from the o-diamines 
 on heating them with acids, their chlorides and anhydrides, as well 
 as with aldehydes. Anhydro-bases or aldehydins (Ladenburg). These 
 are substances nearly related to the glyoxalins or imidazols, and will 
 be treated later in connection with these. Such condensations have 
 been observed also in the reduction of acidylated o-nitro-amido- 
 compounds (Hobrecker). 
 
 4. Cyclic ureas and thio-urea derivatives are formed from COC1 2 and 
 SCC1 2 or CS 2 , also by condensation with urea and thio-urea, as well as 
 with ammonium sulpho-cyanide. 
 
 5. Cyclic guanidin derivatives are obtained by means of carbo- 
 di-imides and phenyl-mustard oils. 
 
 6. A very interesting condensation of the o-diamines is that with 
 glyoxal and other a-dicarbonyl derivatives, as well as with grape- 
 sugar, when quinoxalins result, with rejection of water (Hinsberg) 
 (I- 321). 
 
 Related six-membered rings are produced : 
 
 7. When o-diamines condense with cyanogen ; 
 
 8. By condensation with o-dioxyl-benzol. 
 
 9. Unsym. diamido-phenazin is produced by the oxidation of 
 o-phenylene-diamine. 
 
 10. Dibenzol-sulphone derivatives of o-phenylene-diamine condense 
 with alkylene dihaloids e.g. methylene iodide, ethylene bromide, 
 trimethylene bromide. The products are cj^clic diamines, from which 
 the corresponding phenylene-alkylene-diamines are obtained by the 
 splitting off of the benzol-sulphone groups (B. 28, R. 756). 
 
CONDENSATIONS OF THE o-DIAMINES 
 
 117 
 
 ii. The o-phenylene-diamines condense also with oxalic acid, and 
 the homologous paraffin-dicarboxylic acids, as well as o-phthalic acid, 
 to rings of a higher number of members (A. 327, 9). 
 
 so, 
 
 NO,H 
 
 [2]N/ 
 
 ~C.H< 
 
 HCO H / [i]NH\ rH Benzimidazol; 
 
 -C.H 4 ^ 2 -j N ^ ctl o-Phenylene-formamidin 
 
 COC1, 
 
 C(NC.H.) t 
 
 [i]NH 
 
 [i]NH 
 4 [a]N 
 
 Benzimidazolone 
 o-Phenylene-urea 
 
 -->C.H 4 
 
 CHOCHO 
 
 CN.CN 
 
 >C 4 H 4 J L I J N Ouinoxalin 
 \[2]N=CH V 
 
 OH[i]C.H 4 [2]OH 
 
 /[i]N==CNH, 
 ^ [2]N=CNHj 
 
 C 8 H 4 
 
 BrCH.CHjBr 
 
 ]^!'] \ 
 
 c,H,(NH s ), as-Diamido-phenazin 
 
 C.H 4 
 
 HOCO.COOH 
 
 WNH CH, Tetrahydro-quinoxalin 
 WNH CH, 
 
 /WN= 
 
 \[2]N = 
 
 COH 
 COH 
 
 a, /3-Dioxy-quinoxalin. 
 
 The o-amido-phenols, the o-amido-thio-phenols, and the o-dioxy- 
 benzols show condensations similar to those observed with the o- 
 diamines. 
 
 DIFFERENCES BETWEEN THE o-, m-, AND P-DIAMINES. 
 
 1. The /)aya-diamines are capable of yielding various dyestuffs. 
 Mixed with primary amines (or phenols) and oxidised at the ordinary 
 temperature, they are converted into indoamine and indophenol dye- 
 stuffs ; at higher temperatures the so-called safranins are produced. 
 When oxidised with ferric chloride in the presence of H 2 S, the para- 
 diamines, containing a free NH 2 group, yield sulphurised dyes of thio- 
 diphenyl-amine (Lauth's dyestuffs). Manganese dioxide and sulphuric 
 acid oxidise the p-diamines to quinones, recognisable by their odour. 
 Ferric chloride (B. 17, R. 431) imparts colour to the diamines. See 
 above, o-Phenylene-diamine. 
 
 2. The or^o-diamines, when acted upon by nitrous acid, yield 
 azimido-compounds, e.g. azimido-benzol. The wtfta-diamines, on the 
 contrary, yield yellow-brown azo-dyes, of the type of phenylene brown. 
 Test for nitrous acid (B. 11, 624, 627). In every acid solution, and 
 when there is an excess of acid (nitrous), the meta-diamines form 
 bis-diazo-derivatives. Nitrous acid (or NaNO 2 ) converts the para- 
 diamines (their salts) into bis-diazo-compounds. 
 
 3. When the chlorohydrates of the three isomerides are 
 digested with ammonium sulphocyanide, disulphocyanides, like 
 
 C.H 4 - 
 
 NH 2 .HSCN 
 NH 2 .HSCN 
 
 , are produced. On heating these to 120 we 
 
 discover that the ortho-diamines are changed to cyclic sulpho-ureas 
 
n8 ORGANIC CHEMISTRY 
 
 CS. These are not desulphurised by digestion with an 
 
 alkaline lead solution ; while the derivatives, obtained from the meta- 
 and para-diamines, are immediately blackened by the alkaline lead 
 solution (reaction of Lellmann, B. 18, R. 326). 
 
 4. The diamines unite in a similar manner with the mustard oils. 
 If these products be fused, those from the ortho-diamines decompose 
 into cyclic phenylene-sulpho-urea and dialkyl-sulpho-ureas ; the fused 
 mass soon becomes crystalline. The meta-diamine derivatives melt 
 without decomposition, while those of the para-, after fusion, are 
 completely broken up (B. 18, R. 327 ; 19, 808). 
 
 5. The o-diamines show a series of other condensation reactions, 
 which have been tabulated above; and as the m- and p-diamines 
 behave differently in these transpositions, they will answer for the 
 distinction of the o-derivatives from the other two classes. The 
 behaviour towards phenanthraquinone is used for the detection of the 
 o-diamines. A more delicate test is that with croconic acid (B. 19, 2727). 
 Both tests are based upon the formation of quinoxalin derivatives. 
 
 Triamines. The three triamido-benzols possible theoretically are 
 known, although the symmetrical body only in the form of its salts. 
 
 The adjacent [1,2,3] is obtained from triamido-benzoic acid (from 
 chrysanisic acid), m.p. 103, b.p. 330 (A. 163, 23). The unsymmetrical 
 [1,2,4], m -P- I 3 2 > b.p. 340, is obtained by the decomposition of 
 chrysoidine (B. 10, 659 ; 15, 2196), or diamido-azo-benzol, and from 
 the corresponding nitro-amido-derivatives (B. 19, 1253). When 
 oxidised by air it changes to a eurhodine dyestuff (B. 22, 856). 
 [iCH 3 , 2, 3, 4]-Triamido-toluol (B. 14, 2657). 
 
 Triamido-mesitylene, m.p. 118, see C. 1898, II. 539. Di-, terra-, 
 and hexamethylated triamines, see B. 29, 1053 ; 30, 3110. 
 
 Tetramines. v-, [l,2,3,4]-Tetra-amido-benzol is obtained by the 
 reduction of diquinol tetroxime (B. 22, 1649). The symmetrical 
 (1,2,4,5) variety is formed by the reduction of dinitro-m-phenylene- 
 diamine. It exhibits all the reactions of the ortho- and para-diamines 
 (B. 22, 440). 
 
 Asym. [1,2, 3, 5]-tetramido-benzol, from tetra-nitro-benzol, see 
 B. 34, 57- 
 
 Pentamines. Penta-amido - benzol, from trinitro-m-phenylene- 
 diamine. 
 
 Penta-amido-toluene CH 3 .C 6 (NH 2 ) 5 is formed from trinitro-s- 
 toluylene-diamine (B. 26, 2304). 
 
 As the number of amido-groups increases the polyamines become 
 more unstable. 
 
 In the sym. triamido-benzols the NH 2 groups may be replaced 
 by OH groups, by heating with HC1 ; sym. triamido-benzol becomes 
 phloro-glucin (M. 21, 20 ; 22, 983). 
 
 6. Phenyl-Nitrosamines. 
 
 Nitroso-compounds are obtained when potassium nitrite acts upon 
 the hydrochlorides of secondary aromatic bases. This procedure is 
 similar to that employed with the aliphatic nitrosamines. It is a 
 reaction which can be used to distinguish, and separate, secondary 
 
PHENYL-NITROSAMINES 119 
 
 from primary and tertiary bases, as the nitrosamines are precipitated, 
 as oils, from the acid solution of a mixture of bases. The phenyl- 
 nitrosamines in alcoholic or ethereal solution, when treated with hydro- 
 chloric acid gas, pass into p-nitroso-anilines : 
 
 C ^ 3 NO[ 4 ]C.H 4 [i]NHCH 3 
 
 Methyl-phenyl-nitrosamine p-Nitroso-monomethyl-aniline. 
 
 They change into hydrazins upon reduction, or break down into 
 ammonia, and the original secondary bases. They are volatile with 
 steam (B. 10, 329 ; 22, 1006 ; A. 190, 151), but decompose upon dry 
 distillation. 
 
 The nitrosamines are not only intimately related to the secondary 
 amines and hydrazins, but also to the diazo-compounds. Potassium 
 diazo-benzol may be readily rearranged into potassium iso-diazo- 
 benzol, which yields phenyl-methyl-nitrosamine with methyl iodide. 
 Unsym. phenyl-methyl-hydrazin results from the reduction of phenyl- 
 methyl-nitrosamine. Potassium diazo-benzolate is formed by the 
 oxidation of potassium iso-diazo-benzol. The latter, and methyl 
 iodide, combine to phenyl-methyl-nitramine, which can be reduced 
 to phenyl-methyl-nitrosamine, and unsym. phenyl-methyl-hydrazin. 
 These genetic relations are indicated in the following diagram : 
 
 C H N OK Potassium c H N /NO c H N /NH 2 
 
 8 5 2 ' "Tlso-diazo-benzol T xCH " "* 5 \CH 
 
 Potassium 
 
 diazo-benzol Methyl -phenyl- as-Methyl-phenyl- 
 
 nitrosamine hydrazin 
 
 C 6 H 5 (N 2 S )K 
 
 Potassium Methyl-phenyl- 
 
 diazo-benzolic acid nitro-amine. 
 
 Phenyl-methyl-nitrosamine C 6 H 5 N(CH 3 )NO, m.p. i2-i5 (B. 27, 
 365, footnote), also from nitroso-phenyl-glycin C 6 H 5 N(NO)CH 2 COOH, 
 on boiling with water (B. 32, 247). The methyl group is replaced by 
 potassium when the substance is fused with caustic potash ; potassium 
 iso-diazo-benzol results. In the cold, phenyl-methyl-nitrosamine forms 
 in HC1, in alcohol, a chlorohydrate [C 6 H 5 N(NO)CH 3 ]HC1, which, on 
 boiling or heating, is transposed into the isomeric p-nitroso-methyl- 
 aniline (B. 35, 2975). 
 
 Phenyl-ethyl-nitrosamine C 6 H 5 N(C 2 H 5 )NO is a yellow oil, with 
 an odour like that of bitter almond oil (B. 7, 218). 
 
 Diphenyl-nitrosamine (C 6 H 5 ) 2 NNO, m.p. 66, consists of pale- 
 yellow plates. It dissolves in concentrated sulphuric acid with a 
 dark-blue colour. 
 
 For other aromatic nitrosamines, see B. 33, 100. 
 
 NITROSANILIDES. These bodies are even more closely allied to the 
 diazo-compounds than are the phenyl-alkyl-nitrosamines. They are 
 formed (i) from the anilides in glacial acetic acid solution with nitrous 
 acid ; (2) from the diazo-alkali salts (normal and iso-) with acid 
 chlorides in alkaline solution. Gaseous HC1 breaks them up again 
 into anilides and nitrosile chloride NOC1, and the anilides are always 
 restored by reduction also ; alkalies, on the other hand, split off the 
 
120 ORGANIC CHEMISTRY 
 
 acidyl group even at low temperatures, diazo-alkali salts being formed. 
 With potassium sulphite, nitroso-acetanilide forms benzol-diazo- 
 sulphonic acid and phenyl-hydrazin-disulphonic acid. With benzene, 
 nitrous acetanilide yields diphenyl with evolution of nitrogen (B. 30, 
 366 ; A. 325, 226). 
 
 Nitroso-formanilide C 6 H 5 N(NO)CHO, m.p. 39 ; Nitroso-acetanilide 
 C 6 H 5 N(NO)COCH 3 , m.p. 40 ; p-Bromo-nitroso-acetaniiide, yellow 
 needles, exploding at 88. Nitroso-phenyl-urea C 6 H 5 N(NO)CO.NHC 6 H 5 , 
 m.p. 82 with decomposition, behaves like the nitroso-anilides. 
 
 7. Phenyl-Nitramines. 
 
 Diazo-benzolic acid, nitranilide, phenyl - nitramine C 6 H 5 NH.NO 2 
 or C 6 H 5 N : NOOH, m.p. 46, colourless crystals, formed : (i) by oxida- 
 tion of normal diazo- and iso-diazo-potassium-benzol with potassium 
 ferricyanide or permanganate (B. 28, R. 82), besides the isomeric nitroso- 
 phenyl-hydroxylamine C 6 H 5 N(NO)OH (B. 42, 3568) ; (2) by nitro- 
 genation of aniline by means of nitrogen pentoxide (B. 27, 584 ; cp. 29, 
 1015 ; A. 311, 91) ; (3) by the action of sodium upon an etheric solution 
 of aniline and ethyl nitrate (C. 1905, II. 894) ; (4) by decomposition of 
 diazo-benzol per bromide with alkalies, besides nitroso-benzol (B. 27, 
 1273 ; 28, R. 31) ; (5) from nitrite chloride, and aniline (B. 27, 668) ; 
 (6) from aniline nitrate and acetic oxyhydride, with splitting off, as 
 in the case of acetanilide, from aniline acetate (A. 311, 99). A number 
 of substituted diazo-benzolic acids have been prepared by the above 
 methods. 
 
 Properties and Behaviour. In the light, on heating, and in contact 
 with mineral acids, diazo-benzolic acid is transformed into a mixture 
 of o- and p-nitraniline, with which it is isomeric. It is probable that, 
 during nitrogenation of aniline, diazo-benzolic acid occurs as an inter- 
 mediate product. By reduction with sodium amalgam it passes into 
 sodium-iso-diazo-benzol, and the latter easily into phenyl-hydrazin 
 (B. 27, 1181). With zinc and acetic acid it yields diazo-benzol. It 
 forms salts : a potassium salt C 6 H 5 H 2 O 2 K, and a sodium salt of brilliant 
 white flakes. With ICH 3 the sodium salt gives the a-methyl ester, 
 
 Phenyl-methyl-nitramine C 6 H 5 N<^ 3 , m.p. 39, which, with sulphuric 
 
 ^NC/2 
 
 acid, changes into o- and p-nitro-methyl-aniline, yields methyl-aniline 
 on heating with KHO, and may be reduced to methvl-phenyl-nitros- 
 amine, unsym. methyl- phenyl-hydrazin, and monomethyl- aniline. 
 With methyl iodide the silver salt gives jS-Diazo-benzolic methyl 
 ester C 6 H 5 N : NOOCH 3 , a yellowish-brown oil, smelling of heliotrope 
 (B. 27, 359 J cp. B. 31, 177, 574). 
 
 Homologous Diazo-benzolic Acids. The symmetrical tri-substituted 
 phenyl-nitramines in which the o- and p-positions, with reference to 
 the amido-group, are occupied, do not undergo the transposition into 
 nitraniline. They are stable in the presence of mineral acids, and 
 may therefore be obtained by direct nitrogenation of the corresponding 
 anilines with concentrated NO 3 H. 
 
 o-Diazo-toluolic acid, a colourless oil. p-Diazo-toluolic acid, m.p. 
 52. Diazo-pseudo-cumolic acid, m.p. 87. o-, m-, p - Nitro - diazo- 
 benzolic acid, m.p. 65, 86, m (B. 28, 399). Dinitro-p-tolyl-methyl- 
 
DIAZO-COMPOUNDS 121 
 
 nitramine (NO 2 ) ? C 6 H 2 (CH 3 ).N(CH 8 )NO 2 , m.p. 138, is obtained by 
 the action of nitric acid upon dimethyl-p-toluidin (B. 29, 1015). 
 
 2, 4, 6-Trichloro-phenyl-nitramine, m.p. 135. 2, 4, 6-Tribromo- 
 phenyl-nitramine, m.p. 144 (C. 1905, I. 1231). 2, 4-Dinitro-phenyl- 
 nitramine, m.p. ioiwith decomposition, by the action of concentrated 
 nitric acid upon o- and p-nitraniline or 2, 4-dinitraniline (A. 339, 229). 
 
 2, 4, 6-Trinitro-phenyl-nitramine, extremely explosive, generated as 
 a by-product during nitrogenation of aniline (B. 41, 3094 ; 42, 2959). 
 
 8. Diazo-compounds. 
 
 The aromatic diazo-derivatives, because of their ready conversion 
 into the most varied substitution products of the aromatic hydro- 
 carbons, and as intermediate steps in the formation of azo-dyes, are 
 equally important both from a scientific and technical standpoint. 
 
 The behaviour of the primary aliphatic amines towards nitrous 
 acid was particularly emphasised. As is known, the amido-group can, 
 by this means, be replaced by hydroxyl ; it is a change corresponding 
 to that of ammonia itself by nitrous acid into nitrogen and water : 
 
 NH 3 +NOOH=H 2 O-fN 2 +H 2 O 
 C 2 H 5 NH 2 +NOOH=C 2 H 5 OH+N 2 +H 2 O. 
 
 Among the nitrogen-containing derivatives of the aldehydo-acids 
 we observed a body, in the reaction product resulting from nitrous 
 acid and glycocoll ester, in which the group N=N had joined 
 itself to carbon. This substance has been termed diazo-acetic ester, 
 produced according to the equation : 
 
 CO 2 C 2 H 5 .CH 2 NH 2 +NOOH-CO 2 C 2 H 5 .CH(N 2 )+2H 2 O. 
 
 The moderated action of nitrous acid upon the salts of aromatic 
 primary amines is analogous to its action upon aliphatic a-amido- 
 acid esters. It was, however, observed long before the latter. When 
 nitrous acid acts upon the aqueous solution of salts of primary aromatic 
 amines without cooling the mixture, there follows, as in the case of 
 the aliphatic amines, a replacement of the amido-group by hydroxyl : 
 
 C 6 H 5 NH 2 HCl+NOOH-C 6 H 5 OH4-N 2 +H 2 O-hHCl. 
 
 Upon cooling the solution, however, the three hydrogen atoms will 
 be replaced by a nitrogen atom, thus : 
 
 C 6 H 5 NH 3 C1 + NOOH = C 6 H 6 NC1=N + 2H 2 O 
 
 Diazo-benzol chloride 
 
 C 6 H 5 NH 3 ONO 2 + NOOH = C6H 5 N(O.NO 2 )=N + 2H 2 O 
 
 Diazo-benzol nitrate 
 
 C 3 H 5 NH 3 OSO 3 H + NOOH = C 6 H 5 N(O.SO3H)=N + 2H,O 
 
 Diazo-benzol sulphate. 
 
 These aromatic diazo-bodies differ from the aliphatic, in that 
 the bivalent group N 2 is linked, not with both, but only with one, 
 affinity to the carbon atom. The second affinity is joined to another 
 univalent radicle. Bodies of this class, when boiled with water, 
 yield oxy-compounds : 
 
 C0 2 C 2 H 5 .CHN 2 +H 2 0=C0 2 C 2 H 5 .CH 2 OH+N 2 
 C 6 H B N 2 C1+H 2 0=C 6 H 6 OH+HC1+N 2 . 
 
122 ORGANIC CHEMISTRY 
 
 Formation of Diazo-benzols. (la) Gaseous nitrous acid, made by 
 digesting arsenious acid with nitric acid, is conducted into a paste of 
 the salt to be diazotised. The mixture is cooled all the while with 
 ice. The solution of the diazo-compound is precipitated by a mixture 
 of alcohol and ether, (ib) Add acid to the cooled solution of the 
 salt to be diazotised sufficient (B. 8, 1073 ; 25, 1974, footnote ; 29, 
 R. 1158) to liberate the nitrous acid from sodium or potassium nitrite, 
 the well-cooled solution of which is gradually introduced into the 
 acidified liquid : 
 
 C 6 H 5 NH 2 .HCl+HCl-fNO 2 K-C 6 H 5 N 2 Cl+2H 2 0+KCl. 
 
 (ic) Feebly basic amines, e.g. dinitraniline, which are incapable of 
 forming stable salts in aqueous solution, are dissolved in concentrated 
 nitric acid, and the amount of potassium metabisulphite required for 
 reducing i mol. nitric acid to nitrous acid is introduced (B. 42, 2956) : 
 
 2C 6 H 5 NH 2 .HNO 3 +K 2 S 2 O 6 -f2NO 3 H=2C 6 H 5 N 2 NO 3 4-K 2 S 2 O 7 +4H 2 O. 
 
 (2) As the diazo-benzol salts are more freely soluble in water than 
 in alcohol, in order to obtain solid diazo-salts the diazotising, where 
 practicable, should be made with alkyl nitrites (Vol. I.) dissolved in 
 alcohol or glacial acetic acid (cp. B. 34, 3338 ; C. 1898, I. 295 ; II. 742). 
 
 Sometimes a peculiar migration of the diazo-groups takes place, 
 on mixing the solution of an aniline salt with a diazo-salt solution. 
 Thus, toluol diazo-chlorides and ni tramlines (B. 29, 287) arise from 
 nitro-diazo-benzol chlorides and toluidins : 
 
 N0 2 C 6 H 4 N 2 C1+C 6 H 4 (CH 3 )NH 2 =N0 2 C 6 H 4 NH 2 +C 6 H 4 (CH 3 )N 2 C1. 
 
 (3) Another procedure, occasionally applicable in diazotising, 
 consists in letting zinc dust and hydrochloric acid act upon the nitrate 
 of the diazo-derivative (B. 16, 3080) : 
 
 C 6 H 5 NH 2 .NO 3 H+Zn+3HCl-C 6 H 5 N 2 Cl+ZnCl 2 +3H 2 0. 
 
 (4) By the action of hydroxylamine upon the nitroso-benzols : 
 
 C 6 H 6 NO+H 2 NOH=C 6 H 5 N 1 OH+H 2 0. 
 
 (5) Diazo-benzol nitrate is precipitated upon conducting nitric 
 oxide into a chloroform solution of nitroso-benzol (B. 30, 512). 
 
 (6) By the saponification of nitroso-acetanilide with caustic alkali. 
 
 (7) By the action of mercuric oxide upon the phenyl-hydrazins. 
 
 (8) From phenyl-hydroxylamine, benzol-sulphydroxamic acid, and 
 caustic soda (B. 37, 290) : 
 
 C e H 6 NHOH+C 6 H 6 S0 2 .NHOH+NaOH=C a H 6 N 2 OH+C 8 H 6 S0 2 Na+2H 2 0. 
 
 (9) From phenyl-hydrazin salts with H 2 O, or by the action of 
 chlorine and bromine upon the alcoholic solution of free phenyl-hydra- 
 zins at low temperatures. This last method is very suitable for pre- 
 paring solid diazonium salts. 
 
 (10) From thionyl-phenyl-hydrazone with thionyl chloride, acetyl 
 chloride, and other acid chlorides (A. 270, 116) : 
 
 C e H 5 NH,N ; SO+CH 3 COC1=C 6 H 6 N 2 C1+ S+ CH 3 CO 2 H. 
 
DIAZO-COMPOUNDS 123 
 
 Properties. The acid salts of the diazo-compounds are mostly 
 crystalline, colourless bodies, which speedily brown on exposure to the 
 air. They are readily soluble in water, slightly in alcohol, and are 
 precipitated from the latter solution by ether. Consult B. 28, 1734, 
 2020, for their electric conductivity and cryoscopic behaviour. They 
 are generally very unstable (B. 24, 324), and decompose with a violent 
 explosion when they are heated, or struck by a blow. 
 
 The diazo-derivatives are very reactive, and enter numerous, 
 readily occurring reactions, in which nitrogen is liberated, and the 
 diazo-group in the benzene nucleus directly replaced by halogens, 
 hydrogen, hydroxyl, and other groups. 
 
 History and Constitution. The diazo-compounds were discovered 
 at the close of the '5o's by Peter Griess (A. 137, 39), who regarded 
 their salts as additions of C 6 H 4 N 2 and acids, e.g. HC1. Kekule 
 demonstrated that the azo-group only replaced one hydrogen of benzene, 
 and held on the opposite side the radicle of the acid, e.g. C 6 H 5 N 
 =N.C1 (Z. f. Ch. N.F. (1866) 2, 308 ; Chemie der Benzolderivate, 
 1, 223). Blomstrand, A. Strecker, and E. Erlenmeyer, sen., however, 
 viewed the diazo-salts as ammonium salts, e.g. C 6 H 5 N(C1) = N. 
 
 The proof of the fact that the azo-group N 2 replaces one benzene 
 hydrogen atom is supposed to be found in the existence of such bodies 
 
 /N \ 
 as tetrabromo-benzol-sulphanile-diazide C BI V\ S Q / (B. 10, 1537). 
 
 The relations of the diazo-benzol salts to the hydrazins (E. Fischer, 
 A. 190, 100), and to the mixed azo-compounds, argued in favour of 
 Kekule 's hypothesis. 
 
 In recent years Blomstrand's formula has been accepted for the 
 acid salts of the diazo-bodies (B. 29, R. 93, 783). Comparative studies 
 of the cryoscopic behaviour, and the electric conductivity, of diazo- 
 salt solutions on the one side, and ammonium and alkali salts on the 
 other (B 28, 1734, 2020), have contributed to this assumption. The 
 diazo-salts are compared to the quaternary ammonium salts : 
 
 C 6 H 5 N : N C 8 H 6 N } (CH 3 ) 3 
 
 Cl Cl 
 
 and therefore are termed diazonium salts. From a chemical standpoint 
 this view would indicate, among other things, the power of the 
 diazonium haloids to form additive compounds with the halogens a 
 property which they would hold in common with quaternary ammonium 
 halides as well as with certain alkali metals e.g. caesium, rubidium. 
 This formula also permits of the easy conversion of the aniline salts 
 by means of nitrous acid into diazo-salts, without being compelled to 
 assume, as is necessary in the Kekule formula, the migration of the 
 acid residue from the aniline nitrogen to the nitrogen atom, which has 
 but recently entered : 
 
 The basic hydrates corresponding to the diazonium salts are very 
 unstable (cp. B. 31, 340, 1612 ; 33, 2147), as they probably transform 
 themselves into compounds of Kekule's diazo-type (see above) with 
 atomic displacement, The chemical character of these transposed 
 
124 ORGANIC CHEMISTRY 
 
 hydrates (incapable of isolation) is thereupon changed : they are acids, 
 forming metallic salts such as C 6 H 5 N : NOK, which can be handled. 
 By mineral acids, these metallic salts are changed back into the 
 diazonium salts of the acids. The diazo-alkali salts, or alkaline diazo- 
 tates, are transposed into the more stable iso-diazotates, partly at 
 ordinary temperatures, partly on heating (B. 29, 455). These are 
 distinguished by the difficulty with which they " couple " in alkaline 
 solution, when efforts are made to form azo-dyes, with aromatic amines 
 or phenols (Schraube and Schmidt, B. 27, 514). To these iso-diazo- 
 tates the structure C 6 H 5 NMe.NO was originally ascribed. They were 
 derived from the " nitrosamine " form of the diazo-bodies, since, with 
 methyl iodide, they yielded phenyl-methyl-nitrosamine. But it has 
 been found possible, in several cases, to obtain, from the iso-diazotates, 
 acid hydrates containing hydroxyl, by acidulating them. But these, 
 as a rule, change rapidly into the more stable " nitrosamine" forms 
 ArNH.NO (cp. Vol. I., Pseudo-acids, and B. 35, 2964). 
 
 According to Hantzsch (Die Diazoverbindungen, Stuttgart, 1902), 
 the isomerism of the diazo-metallic salts of identical structure is based 
 upon stereo-isomerism (see Vol. I., Stereo-isomerism of ethylene deriva- 
 tives, and Vol. II., Benzaldoxime), according to the formula : 
 
 C 6 H 5 N C 6 H 5 N 
 
 KOlSr NOK 
 
 Syn-diazo-benzol-potassium Anti-diazo-benzol-potassium. 
 
 The difference in the coupling power (see above), and in other 
 reactions of the normal and the iso-diazotates, respectively, is attributed 
 by Hantzsch to the larger energy content of the former, in comparison 
 with the latter ; the two groups of diazotates might therefore also be 
 distinguished as the " unstable " and " stable " groups respectively 
 (see also Vol. I., Dynamic isomerism). 
 
 There are therefore four classes of diazo-bodies, also more or less 
 convertible into one another : (i) diazonium salts ; (2) normal, 
 " syn-," or "unstable" diazotates; (3) iso-, " anti-," or "stable" 
 diazotates ; (4) primary nitrosamines. Their transitions correspond 
 to the following scheme : 
 
 C 6 H 5 N(OH)N ^ C 6 H 5 N : N(OH) ^ C 6 H 5 NH.NO. 
 
 As of the diazo-metallic salts, so also of the diazo-benzol-sulphonic 
 salts, and especially of the diazo-cyanides (see below), isomeric series 
 have been discovered: ArN 2 CN may be diazonium cyanide as well 
 as unstable, or stable, diazo-cyanide (benzol-azo-cyanide, cp. nomen- 
 clature, B. 33, 2556). 
 
 i. DIAZONIUM SALTS. Diazo-benzol chloride C 6 H 5 NC1 = N, colour- 
 less needles (B. 23, 2996 ; 28, 2053). The platinum salt, [C 6 H 5 N 2 C1] 2 
 PtCl 4 , consists of yellow prisims. The gold salt, C 6 H 5 N 2 Cl.AuCl 3 
 (A. 137, 52). Mercury salt, C 6 H 5 N 2 Cl.HgCl 2 , consists of white needles, 
 decomposing at 122. 
 
 Diazo-benzol bromide C 6 H 5 .N 2 Br separates in white laminae, if 
 bromine be added to the ethereal solution of diazo-amido-benzol. 
 Tribrom-aniline remains in solution. 
 
 Diazo-benzol bromide cuprous bromide C 6 H 5 N 2 Br.Cu 2 Br 2 , con- 
 
DIAZONIUM SALTS 125 
 
 sisting of reddish-yellow needles, is decomposed by water into cuprous 
 bromide, nitrogen, and bromo-benzol (B. 28, 1741). Concerning 
 Benzol-diazonium fluorides like C 6 H 5 N 2 F.HF, and benzol-diazonium- 
 azides like NO 2 C ? H 4 N 2 .N 3 , see B. 36, 2056, 2059. 
 
 Diazo-per-halides. The diazonium halides readily add two halogen 
 atoms, but of the ten possible combinations with the halogens, chlorine, 
 bromine, and iodine, the trichloride is the only one that has not been 
 prepared. It may be remarked that the compound C 6 H 5 N 2 BrICl 
 can be prepared both from the chloride and BrI, and from the bromide 
 and C1I (B. 28, 2754). 
 
 Diazo-benzol perbromide C 6 H 5 .N 2 Br 3 is precipitated from the 
 aqueous solution of diazo-benzol nitrate or sulphate by bromine in 
 HBr acid or NaBr. It is a dark-brown oil, which quickly becomes 
 crystalline. It is insoluble in water and ether, and crystallises from 
 cold alcohol in yellow laminae. Continued washing with ether con- 
 verts it into diazo-benzol bromide. In moist air it decomposes, 
 forming phenol and tribromo-phenol. Chemically, it behaves like a 
 mixture of diazo-benzol bromide and free bromine. Many compounds 
 may thus be brominated with diazo-benzol perbromide, with simul- 
 taneous formation of HB and benzol-diazonium bromide. It is 
 changed by aqueous ammonia to diazo-benzol imide. Alkalies decom- 
 pose it into nitroso-benzol and potassium-diazo-benzol. Boiling 
 alcohol converts it into bromo-benzol. 
 
 Diazo-benzol nitrate C 6 H 5 N 2 O.NO 2 consists of long, colourless 
 needles, which explode with greater violence than fulminating mercury 
 or nitrogen iodide when they are gently heated, struck, or subjected 
 to pressure. 
 
 Diazo-benzol sulphate C 6 H 5 .N 2 .SO 4 H consists of colourless needles 
 or prisms, which dissolve readily in water. It explodes at 100. It 
 is prepared either by diazotising aniline sulphate or by allowing 
 sulphuric acid to act upon diazo-benzol nitrate (B. 28, 2049). 
 
 Diazo-benzol perchlorate C 6 H 5 N 2 O.C1O 4 is distinguished by its 
 difficult solubility, like potassium perchlorate. On adding perchloric 
 acid to an aqueous solution of diazo-benzol chloride, it precipitates 
 in the form of prismatic needles, which explode with extreme violence, 
 even in a moist condition. 
 
 Oxalate (B. 28, 2059). 
 
 Carbonate, nitrite, acetate (B. 28, 1741). 
 
 Diazonium cyanides, corresponding to diazonium haloids, have 
 been obtained in the form of their silver double cyanides, e.g. 
 p-bromo-diazonium silver cyanide BrC 6 H 4 N(CN)N.AgCN (B. 30, 
 2546 ; cp. also anisol-diazonium cyanide, B. 34, 4166) ; the diazonium 
 cyanides are equally isomerised to diazo-cyanides. 
 
 Diazo-benzol sulphoeyanide C 6 H 5 N 2 .SCN is a yellow, very explosive 
 mass, obtained from diazo-benzol chloride and potassium sulpho- 
 cyanide. p-Chloro-diazo-benzol sulphocyanide C1[4]C 6 H 4 N 2 .SCN re- 
 arranges itself with ease into p-Sulphoeyano-diazo-benzol chloride 
 CNS[4]C 6 H 4 N 2 C1 (B. 29, 947). Such a change of place between 
 nucleus-substituting atoms, and the acid residue of the diazonium group, 
 has become known in a number of further cases ; it only occurs in the 
 o- and p-positions of the nucleus substituent ; thus, 2, 4-dibromo- 
 benzol-diazonium chloride yields a chloro-bromo-diazonium bromide ; 
 
126 ORGANIC CHEMISTRY 
 
 and 2, 4, 6-tribromo-diazonium chloride, a dibromo-chloro-diazonium 
 bromide (B. 31, 1253 ; 33, 505 ; 36, 2069). 
 
 p-Phenylene-bis-diazo-chloride C 6 H 4 (N 2 C1) 2 consists of yellow- 
 coloured, very explosive needles (B. 30, 92). 
 
 2. NORMAL DIAZO-HYDRATES are not known in a free state. In 
 attempting to separate them by acids from their potassium salts, 
 yellow-coloured, exceedingly explosive, and unstable precipitates are 
 obtained, under certain conditions. These appear to be not hydrates, 
 but anhydrides, e.g. diazo-benzol anhydride [C 6 H 5 N 2 ] 2 O ; p-ehloro- 
 diazo-benzol anhydride [C1C 6 H 4 N 2 ] 2 O. These bodies redissolve in 
 acids to diazonium salts, in alkalies to diazo-metallic salts, in ammonia 
 to bis-diazo-amido-bodies, in anilines to diazo-amido-compounds 
 (B. 29, 451), in HCN, diazo-cyanides, and with benzol-sulphinic acid, 
 diazo-sulphones (B. 29, 451 ; 31, 637). 
 
 Normal diazo-benzol potassium C 6 H 5 N 2 OK is produced on intro- 
 ducing a saturated aqueous solution of diazo-benzol chloride into an 
 excess of highly concentrated caustic potash (B. 29, 461). It forms 
 white, pearly flakes which can be quantitatively reconverted into 
 diazo-benzol chloride. Normal sodium-diazo-benzol is formed in 
 small quantities by the action of sodium amide upon nitro-benzol 
 (B. 37, 629), or of NH 2 OH upon nitro-benzol in alkaline solution (B. 
 38, 2056). It yields diazo-esters in the cold, with alcohols (B. 29, 
 488) ; see B. 30, 339, for the reduction of potassium diazo-benzol to 
 phenyl-hydrazin. When alkaline diazo-benzol solutions are oxi- 
 dised with potassium ferricyanide or potassium permanganate, the 
 principal product is diazo-benzol acid, together with a little nitroso- 
 benzol, nitro-benzol, azo-benzol, and diphenyl. Benzoyl chloride and 
 sodium hydroxide change normal potassium diazo-benzol into nitroso- 
 benzanilide C 6 H 5 N(NO).CO.C 6 H 5 (B. 30, 214). Salts of the heavy 
 metals with diazo-benzol are obtained by the precipitation of solu- 
 tions of potassium diazo-benzol with metallic salts (B. 23, 3035 ; 
 28, 226). 
 
 Diazo-benzol methyl ether C 6 H 5 N 2 .OCH 3 , isomeric with methyl- 
 phenyl-nitrosamine, is obtained from normal or iso-diazo-benzol silver 
 and methyl iodide, as well as from diazo-benzol potassium and methyl 
 alcohol. It is a yellow, volatile oil, rapidly turning dark in colour, 
 possessing a penetrating, stupefying odour, and decomposing shortly 
 after its liberation. Boiling dilute sulphuric acid decomposes it into 
 nitrogen-methyl alcohol, and phenol (B. 28, 227, 236). o- and p- 
 Nitro-diazo-benzol methyl ether NO 2 .C 6 H 4 N 2 .OCH 3 (B. 28, 236). 
 
 On saponification with alkali in the cold, the diazo-ethers give 
 normal diazo-alkali salts (B. 36, 4361). 
 
 Di-p-nitro-phenyl-diazo-sulphide [NO 2 [4]C 6 H 4 N 2 ] 2 S is precipitated 
 as an egg-yellow, very explosive mass, on adding hydrogen sulphide 
 to a neutral solution of the diazo-chloride. With benzene it forms 
 nitro-diphenyl, nitrogen, and sulphur ; di-p-nitro-diphenyl disulphide 
 is formed simultaneously. In an acid solution with an excess of 
 hydrogen sulphide there is produced, along with the diazo-sulphide, 
 p-Nitro-phenyl-diazo-mercaptan hydrosulphide NO 2 .C 6 H 4 N 2 SH.SH 2 , 
 consisting of red, brilliant, metallic-looking needles, which dissolve 
 with a deep-red colour in the alkalies. They decompose, when fused, 
 with the formation of nitro- phenyl-hydrazin, nitraniline, sulphur, 
 
ISO-DIAZO-HYDRATES 127 
 
 and dinitro-phenyl disulphide. Non-explosive Di - p - nitro - phenyl - 
 diazo-disulphide [NO 2 C 6 H 4 N 2 ] 2 S 2 is finally the third product in the 
 action of hydrogen sulphide. It is insoluble in alkali. It consists of 
 sulphur-yellow needles, soluble in acetone (B. 29, 272). See Thio- 
 phenol for diazo-benzol-thio-phenyl ether. 
 
 3. ISO-DIAZO-HYDRATES are liberated from their potassium salts by 
 acetic acid. They are very easily decomposed. Those of benzene 
 and toluol are colourless oils. These substances are mostly, however, 
 not the real hydrates, but their pseudo-forms : primary aryl-nitros- 
 amines ArNH.NO. In some cases, as in the dibrom-anisol-diazo- 
 hydrate, the hydroxyl forms have been isolated as unstable precipitates 
 easily passing into nitrosamines. In undissociating solvents they 
 react energetically with NH 3 , acetyl chloride, and PC1 5 , whereas the 
 nitrosamine forms remain indifferent (B. 35, 2964). 
 
 Potassium iso-diazo-benzol C 6 H 5 N 2 OK is formed on digesting 
 potassium diazo-benzol for a brief period at I30-I35 with concen- 
 trated caustic potash ; and when fused, caustic potash acts upon phenyl- 
 methyl-nitrosamine, into which it returns upon treatment with methyl 
 iodide (B. 27, 514, 672, 680). Sodium amalgam reduces it with ease 
 to phenyl-hydrazin (B. 29, 473 ; 30, 339). With benzoyl chloride 
 and sodium hydrate, as well as during oxidation, it behaves like the 
 normal diazotate, but differs from the latter qualitatively by the 
 omission of dye-formation, e.g. on mixing with j3-naphthol in alkaline 
 solution (B. 27, 517). Potassium iso-diazo-benzol is also formed direct 
 from aniline and phenyl-hydrazin by the action of alkyl nitrite and 
 alkali alcoholate, liberating nitrous oxide in the latter case (B. 33, 3511 ; 
 41, 2808) ; it has also been obtained from oxy-azoxy-benzol C 6 H 5 
 (N 2 O)C 6 H 4 OH by oxidising decomposition with MnO 4 K (B. 33, 1957). 
 Potassium iso-p-diazo-toluol results when its isomeride is exposed to 
 the air (B. 29, 1385). Sodium iso-p-nitro-diazo-benzol C 6 H 4 (NO 2 ) 
 N 2 ONa+2H 2 O yields nitro-phenyl-methyl-nitrosamine with methyl 
 iodide, whereas the silver salt forms the corresponding diazo-ester 
 (B. 29, 1384). 
 
 4. DIAZO-BENZOL SULPHONIC ACID, benzene azo-sulphonic acid 
 C 6 H 5 N 2 SO 3 H, is very decomposable (B. 30, 75). Its potassium salt 
 is produced upon introducing diazo-benzol nitrate into a cold, neutral, 
 or feebly alkaline solution of di-potassium sulphite ; the liquid solidi- 
 fies to a yellow, crystalline mass. Under other conditions a more 
 easily decomposable, orange-coloured salt is formed (B. 27, 1715, 
 2930). For the sensitivity of the diazo-benzol sulphonates to light, 
 and their application in photography, consult B. 23, 3131. Mono- 
 potassium sulphite reduces diazo-benzol nitrate to potassium phenyl- 
 hydrazin sulphonate, which mercuric oxide oxidises to potassium 
 diazo-benzol sulphonate (B. 27, 1245). 
 
 p-Nitro-diazo-benzol nitrate and one molecule of K 2 SO 3 yield 
 potassium p-nitro-diazo-benzol sulphonate, which also appears to exist 
 in two forms. The acid crystallises, with four molecules of water, in 
 ruby-red prisms (B. 30, 90). On using two molecules of potassium 
 sulphite the product is potassium p- nitro -phenyl-hydrazin disul- 
 phonate C 6 H 4 (NO 2 )N(SO 3 K)NH.SO 3 K (B. 29, 1829). p-Chloro- and 
 p-bromo-benzol-diazo-sulphonic acid (B. 30, 75). 
 
 The diazonium salts and benzene-sulphinic acid combine to Benzene- 
 
128 ORGANIC CHEMISTRY 
 
 diazo-sulphones C 6 H 5 N 2 SO 2 C 6 H 5 , which are resolved by hydro- 
 chloric acid into diazonium chlorides and sulphinic acids (B. 30, 312). 
 
 With substances containing the grouping C 6 H 5 N : NX, e.g. benzol- 
 diazo-cyanides and the azo-compounds, benzol-sulphinic acid forms 
 colourless addition products, mostly stable in water and acids : 
 C 6 H 5 N(SO 2 C 6 H 5 )NHX. These should be regarded as derivatives of 
 hydrazo-benzol, and are split up into their components by alkalies 
 (B. 30, 2548). The action of SO 2 upon p-nitro-diazo-benzol hydrate 
 produces p-Nitro-phenyl-diazo-p-nitro-phenyl sulphone NO 2 C 6 H 4 N : 
 NSO 2 C 6 H 4 N0 2 (B. 35, 661). 
 
 5. DIAZO-BENZOL CYANIDE C 6 H 5 N 2 CN appears as an unstable oil, 
 on adding a potassium cyanide solution to the solution of a diazo- 
 benzol salt. If, however, the reverse be done the diazo-salt be added 
 to the potassium cyanide solution a prussic acid additive product, 
 C 6 H 5 N 2 CN.HCN, will separate as a yellow precipitate, m.p. 70. Ben- 
 zene-diazo-carboxyl-amide, phenyl-azo-carbamide C 6 H 5 N : NCONH 2 , 
 results from the oxidation of phenyl-semicarbazide (/. Ch. Soc., 1895, 
 i, p. 1067 ; B. 28, 1925, 2599). It consists of reddish-yellow needles, 
 m.p. 114. The anilide C 6 H 5 N 2 CONHC 6 H 5 , from i, 4-diphenyl-semi- 
 carbazide (B. 29, 1691), m.p. 122. 
 
 Two isomerides have been obtained from p-chloro- and p-nitro- 
 diazo-benzol cyanide, and in each instance the one body is unstable 
 and the other stable. The unstable, low-melting modifications only 
 form at lower temperatures, decompose easily, especially in contact 
 with copper powder, give up nitrogen with the formation of 
 benzene cyanides, form azo-dyes with aromatic amines or phenols, 
 and change rapidly, particularly in alcoholic solution, or in sun- 
 light, into the stable isomerides (C. 1906, II. 1054). This trans- 
 position is influenced by the nature and position of the nuclear 
 substituents. With a less straightforward course it can also be 
 obtained through the intermediary of benzol-sulphinic addition 
 products (B. 30, 2553). 
 
 Unstable p-chloro- and p-nitro-diazo-benzol cyanide melt at 28 
 and 29 respectively, the stable forms at 106 and 86 respectively. 
 2, 4, 6-Tribromo-benzol-diazo-cyanide, unstable form, m.p. 6p ; stable 
 form, m.p. 147. The stable cyanides approach, in their behaviour, 
 the azo-bodies. With prussic acid they readily combine to form 
 imido-cyanides (see above) ; with water, diazo-carboxyl amides ; with 
 alcohols, amido-ethers, from which, by saponification, the potassium 
 salts of the corresponding diazo-benzol-carboxylic acids are obtained ; 
 the acids are very easily decomposed (B. 28, 670, 2072 ; 30, 2529). 
 Tribromo-benzol-azo-carboxylic acid C 6 H 2 Br 3 .N 2 COOH is obtained 
 from its amide, the oxidation product of tribromo-phenyl-semi- 
 carbazide (B. 28, 1929). 
 
 CHIEF DECOMPOSITIONS OF THE DIAZO-BENZOL SALTS. 
 
 The decompositions of diazo-salts in which atoms of metal- 
 loids or atomic groups take the place of nitrogen and expel the 
 latter, are of the greatest importance for the relations of many 
 different di- and poly-substitution products of benzene, and its 
 homologues. 
 
CHIEF DECOMPOSITIONS OF DIAZO-BENZOL SALTS 129 
 
 1. Replacement of the Diazo-group by Hydrogen. (a) On heating 
 diazonium salts with alcohols, two reactions may take place : 
 
 I. C 6 H 5 N 2 C1+C 2 H 5 OH=C 6 H 5 OC 2 H 5 +HC1+N 2 
 II. C 6 H 5 N 2 C1+C 2 H 5 OH =C 6 H 6 +C 2 H 4 0-fHCl+N 2 . 
 
 Reaction I. yields phenol-ether, and reaction II. benzene-hydro- 
 carbons with aldehyde as a by-product (A. 137, 69 ; 217, 189 ; B. 
 9, 899 ; 17, 1917 ; 18, 65). Often these two reactions are simultane- 
 ous : solid benzol-diazonium chloride or sulphate, with absolute methyl- 
 alcohol, gives anisol ; with ethyl-alcohol, phenetol and a little benzene ; 
 in the negatively substituted benzols, the replacement of the diazo- 
 group by hydrogen steps into the foreground. Multi-valent alcohols, 
 on the other hand, only appear to form phenol-ether (B. 34, 3337 ; 
 35, 998 ; 36, 2061). Sunlight favours reaction I. (C. 1905, II. 129). 
 
 Heating with phenols also converts diazonium salts partly into 
 phenyl-ether, with evolution of nitrogen ; but oxy-diphenyls are mainly 
 generated (C. 1903, I. 705). 
 
 (b) The aryl-hydrazins formed by reduction of the diazo-com- 
 pounds (cp. phenyl-hydrazin) are so oxidised by boiling with copper 
 sulphate, ferric chloride, potassium chromate, or sodium hypochlorite 
 that an H atom takes the place of the hydrazin group, with evolution 
 of nitrogen : 
 
 C 6 H 5 NHNH 2 +0=C 6 H 6 +N 2 +H 2 0. 
 
 The intermediate formation of hydrazins, subsequently oxidised 
 by unchanged diazo-compounds (B. 36, 813), is probably also the 
 cause of the following reactions in which H displaces the diazo-group : 
 
 (c) Boiling of diazonium chlorides with stannous chloride solution 
 (B. 22, R. 741). 
 
 (d) Action of hypo-phosphonic acid upon diazonium salts (B. 35, 
 162 ; A. 320, 143). 
 
 (e) Solution of the diazo-compound in caustic soda, and soda- 
 stannous oxide (B. 36, 813). Iso-diazotates are not reduced by the 
 latter (B. 36, 2065). 
 
 (/) Boiling with formic acid converts diazonium salts, almost ex- 
 clusively, into the corresponding hydrocarbons : 
 
 C 6 H 5 N 2 C1+HCOOH=C 6 H 6 +N 2 +CO 2 +HC1. 
 
 Glacial acetic acid yields nothing but acetyl-phenols (B. 23, 1632 ; 
 C. 1907, I. 1031). 
 
 2. Replacement of the Diazo-group by Halogens. (a) The diazo- 
 benzol salts are treated with haloid acids. Of the four acids of this 
 class, hydriodic acid reacts most readily : 
 
 C 6 H 5 N 2 .OS0 3 H+HI=C 6 H 5 I+N 2 +SO 4 H 2 . 
 
 The haloid acids are frequently applied in glacial acetic acid solution. 
 The hydro-bromides or hydro-iodides of the bases can also be treated 
 with nitric acid. 
 
 (b) Concentrated haloid acids are allowed to act upon the diazo- 
 amido-derivatives. This reaction is especially recommended for the 
 preparation of fluoro- or chloro-derivatives (B. 21, R. 97) : 
 
 C 6 H 5 .N : N-NH.C 6 H 5 +2HF1=C 6 H 5 F1+N 2 +F1H.NH 2 .C 6 H 5 . 
 
 VOL. II. K 
 
130 ORGANIC CHEMISTRY 
 
 (c) Chloro- and bromo-derivatives are formed, if the PtCl 4 - and 
 PtBr 4 - double salts are heated alone ; or, which is better, with dry 
 soda or salt : 
 
 (C 6 H 5 N 2 Cl) 2 PtCl 4 -:2C 6 H 5 Cl+2N 2 +Pt+2Cl 2 . 
 
 (d) When the diazo-perbromides are boiled with alcohol (the latter 
 is oxidised to aldehyde), bromo-benzols are formed : 
 
 C 6 H 5 N 2 Br 3 +CH 3 CH 2 OH=C 6 H 5 Br+N 2 +2HBr+CH 3 CHO. 
 
 The reactions indicated under a, b, c, and d were all observed by 
 P. Griess. Another reaction belongs to this group ; it was discovered 
 by Sandmeyer (B. 17, 2650 ; 23, 1880), and is capable of far greater 
 generalisation. It is based upon the fact that diazo-salts are decom- 
 posed by cuprous salts : 
 
 (e) When cuprous chloride is added to an aqueous solution of diazo- 
 benzol * chloride, an addition product, C 6 H 5 N 2 ClCu 2 Cl 2 , is formed at 
 first, but upon the application of heat this decomposes into C 6 H 5 C1 
 (B. 19, 810 ; 23, 1628 ; 33, 2544) : 
 
 C 6 H 5 N 2 Cl(Cu 2 Cl 2 )-C 6 H 5 Q+N 2 +Cu 2 Cl 2 . 
 
 Cuprous bromide and cuprous iodide act similarly upon the corre- 
 sponding diazo-benzol salts. If cuprous bromide acts upon a diazo- 
 nium salt, the corresponding bromo-benzol is produced under suitable 
 conditions, which proves that the cuprous haloid takes an essential 
 part in the process. 
 
 A modification of the method consists in treating the diazo-deriva- 
 tives in the presence of hydrochloric, hydrobromic, or hydro-iodic acid 
 with copper powder (B. 23, 1218 ; 25, 1091, footnote). The latter 
 seems to act catalytically. 
 
 3. Replacement of the Diazo-group by Hydroxyl. When the salts 
 (sulphates are best) are boiled with water, the diazo-group will be 
 replaced by hydroxyl : 
 
 C 6 H 5 N 2 Br +H 2 0=C 6 H 5 OH+N 2 +HBr 
 C 6 H 5 N 2 N0 3 +H 2 0=C 6 H 5 OH+N 2 +N0 3 H 
 C 6 H 5 N 2 S0 4 H+H 2 0=C 6 H 5 OH+N 2 +S0 4 H 2 . 
 
 This method often fails in negatively substituted diazonium salts. 
 But it also succeeds, in these cases, on replacing the water by a mixture 
 of dilute sulphuric acid and sodium sulphate (C. 1905, II. 617). 
 
 On decomposing diazo -nitrates, nitro-phenols are formed as by- 
 products. On the velocity of phenol splitting, see A. 325, 292 ; B. 
 31, 35I9- 
 
 4. Replacement of the Diazo-group by the Sulphydrate Group. 
 On digesting the diazide of sulphanilic acid (q.v.), a cyclic diazo-salt, 
 with alcoholic potassium sulphide, the potassium salt of p-thio-phenol- 
 sulphonic acid will be produced (B. 20, 350) : 
 
 r[i]N a x r[i]SK 
 
 QH4 1 [ 4 ]S0 3 / K2S : : CfiH4 \ [ 4 ]S0 3 K + 
 In the same manner, when mercaptan acts upon diazo-benzol- 
 
CHIEF DECOMPOSITIONS OF DIAZO-BENZOL SALTS 131 
 
 sulphonic acid, a compound results which, upon standing or warming, 
 decomposes into thio-phenol-ethyl-ether-p-sulphonic acid : 
 
 r H /N 2 \ C,H.SH /N 2 SC,H 5 -N. 
 
 C " H4 \S0 3 / C H *\S0 3 H C 
 
 With xanthogenic salts (Vol. I.) the diazonium salts form aromatic 
 xanthogenic acid esters, like C 6 H 5 S.CSOC 2 H 5 , which, on saponification, 
 yield thio-phenols (/. pr. Ch. 2, 41, 184). 
 
 For the reaction of diazonium salts with thio-glycolic acid, see 
 C. 1908, I. 1221. 
 
 5. Replacement of the Diazo-group by the Sulphinic Acid Residue 
 is brought about by conducting sulphurous acid through solutions of 
 diazonium sulphates, or treating them with alcoholic SO 2 solution, 
 bisulphite, and Cu powder (B. 32, 1136 ; C. 1902, I. 959) : 
 
 C 6 H 5 N 2 (S0 4 H)+S0 2 -hCu=C 6 H 5 S0 2 H+N 2 +S0 4 Cu. 
 
 6. Replacement of the Diazo-group by the Nitro-group. The diazo- 
 benzol nitrite solution is added to freshly precipitated cuprous oxide, 
 or the solutions of diazonium, and mercury nitrites, are decomposed 
 with Cu powder (B. 33, 2551). 
 
 7. In a few cases the diazo-group may be replaced by amine 
 residues, e.g. in the diazide of amido-anthra-quinone-sulphonic acid 
 by treatment with ammonium carbonate or amines (B. 35, 2593). 
 
 8. Replacement of the Diazo-group by the Cyanogen Group. This 
 reaction connects by easy stages the nitro-amido-benzols with the 
 nitro-benzoic acids, and the latter with the phthalic acids. The im- 
 portance of this fact has been mentioned. Add the diazo-benzol 
 chloride solution to a copper sulphate solution mixed with potassium 
 cyanide (B. 20, 1495 ; 23, 1630) : 
 
 C 6 H 5 N 2 CN=C 6 H 5 CN+N 2 . 
 
 9. Sulpho-cyanides (rhodanides) result when the diazo-salts are 
 boiled with potassium, and cuprous sulpho-cyanides (B. 23, 770). 
 
 10. When a solution of diazo-benzol sulphate is mixed with potas- 
 sium cyanate, and reduced copper is then added (B. 25, 1086), phenyl 
 iso-cyanide or carbanile will result. 
 
 11. Formation of Diphenyl Compounds from Diazo-derivatives. 
 Diphenyl derivatives frequently appear as by-products in the treat- 
 ment of diazo-bodies with reducing agents e.g. stannous chloride 
 (B. 18, 965), alcohol, and reduced copper (B. 23, 1226), alcohol alone 
 or sodium ethylate (B. 28, R. 389) as well as in the action of water, 
 of phenol (B. 23, 3705), and of potassium ferricyanide (B. 26, 471). 
 Into aromatic hydrocarbons and heterocyclic compounds e.g. thio- 
 phene, pyridin, and quinolin diazo-benzol chloride introduces the 
 phenyl group. This occurs very easily in the presence of aluminium 
 chloride (B. 26, 1994) : 
 
 C 6 H 5 N 2 C1 + C 6 H 6 > C 6 H 5 C 6 H 5 + N 2 + HCL 
 The diazo-residue in the diazo-oxides, diazo-sulphides, and iso- 
 
132 ORGANIC CHEMISTRY 
 
 diazo-hydrates is readily replaced by cyclic residues (B. 28, 404 ; 29, 
 165, 274, 452) : 
 
 [N0 2 C 6 H 4 N 2 ] 2 S +2C 6 H 8 =2N0 2 C 6 H 4 .C 6 H 6 +N 2 +H 2 S 
 C 6 H 6 N 2 OH+C 6 H 5 N (pyridin) =C e H 6 .C 6 H 4 N+N 2 +H 2 O. 
 
 12. On treating diazonium salts with amm. cuprous oxide solu- 
 tion, they are mostly converted into azo-benzols with evolution of N : 
 
 2C 6 H 5 N 2 Cl+Cu 2 0-C 6 H 5 N : NC 6 H 5 -f N 2 +CuCl 2 +CuO ; 
 
 whereas the diazonium salts, from o- and p-nitraniline, usually give 
 the corresponding diphenyl derivatives (A. 320, 122). 
 
 13. The reactions n and 12 are simultaneous when saturated 
 potassium ferrocyanide solution acts upon diazonium salts, the azo- 
 compounds of the diphenyl series being produced (C. 1907, 1. 1789). 
 
 Other Reactions of Diazo-derivatives, in which nitrogen is not 
 set free : 
 
 1. Phenyl-hydrazins are produced in the reduction of diazo-salts. 
 The action of benzol-diazonium chloride upon zinc-ethyl, in etheric 
 
 solution, produces ethylated phenyl-hydrazins and also diethyl- 
 benzidin (B. 35, 4179 ; C. 1905, I. 79). 
 
 2. When diazo-compounds are oxidised in alkaline solution, they 
 are converted into nitroso-benzol and phenyl-nitro-amine or diazo- 
 benzol acid. 
 
 3. The behaviour of diazo-bodies toward ammonia, alkylamines, 
 aniline, and related bases, when diazo-imido-, diazo-amido-, and 
 mixed azo-derivatives arise, is worthy of special note. These very 
 important reactions will be given in detail, with the individual classes. 
 
 4. Hydrazones result when diazo-benzol, in alkaline solution, acts 
 upon bodies containing the group CH 2 CO. The primarily formed 
 hydrazones often rearrange themselves, with additional quantities of 
 the diazo-benzol salt, into formazyl derivatives, which belong to the 
 class of amidines (B. 27, 147, 320, 1679 ; 29, 1386 ; 31, 3122 ; 32, 2880). 
 
 9. Diazo-amido- compounds. 
 10. Dis-diazo-amido-compounds. 
 
 The diazo-amido-compounds are derived from the unknown hydride 
 NH=N NH 2 , in which the hydrogen of the imide group is replaced 
 by an aromatic residue e.g. phenyl, tolyl, etc. and the hydrogen 
 of the amido-group by aliphatic or aromatic residues : mixed 
 and true aromatic diazo-amido-compounds. The dis-diazo-amido- 
 bodies are also derivatives of an unknown nitrogen hydride, 
 NH=N NH N=NH. 
 
 Formation of Diazo-amido-derivatives. They result from the 
 transposition of primary and secondary amines with diazo-salts : 
 
 la. Primary aromatic amines yield diazo-amido- or dis-diazo- 
 amido-bodies, depending upon the conditions of experiment. Diazo- 
 amido-compounds are formed when equimolecular quantities of diazo- 
 salt and primary amine interact : 
 
 : N.NHC 6 H 5 +HC1. 
 
DIAZO-AMIDO-COMPOUNDS 133 
 
 Substituted anilines containing the substituent in p- or o-position 
 react essentially like aniline itself, but in meta-substituted anilines, 
 like m-toluidin, the formation of amido-azo-compounds becomes pro- 
 minent (/. pr. Ch. 2, 65, 401). 
 
 Diazo-amido-compounds are also produced when an alkali nitrite, 
 in the absence of mineral acids, acts upon the salts of primary amines : 
 
 2C 6 H 5 NH 2 HC1+N0 2 K=C 6 H 5 N : N.NH.C 6 H 5 +KC1+HC1+2H 2 O. 
 
 ib. A dis-diazo-compound results if a molecule of aniline be 
 allowed to act, in alkaline, alcoholic solution, upon two molecules of 
 a diazo-benzol salt. It can also be obtained by transposing diazo- 
 benzol chloride with diazo-amido-benzol (B. 27, 703) : 
 
 2 C a H 5 N 2 Cl+C 6 H 5 NH 2 - 5 NCe H 5 + 2 HC1 
 
 V^jJtlgJN I JN/ 
 
 C 6 H 5 N 2 C1+C.H 5 N : N.NHC,H 5 = * : >NC.H. + HC1. 
 
 Primary aliphatic amides react, with special readiness, with diazo- 
 benzol chloride, forming dis-diazo-amido - compounds, so that the 
 isolation of the simple aliphatic-aromatic diazo-amido-compounds 
 only succeeds under special conditions (B. 38, 2328). 
 
 When a diazo-benzol salt solution is allowed to flow into cold, 
 concentrated ammonia, dis - diazo - benzol - amide C 6 H 5 N : N.NH.N : 
 NC 6 H 5 (B. 28, 171) will be produced. 
 
 The normal diazo-alkali salts also yield diazo-amido-compounds 
 (B. 29, 289). The iso-diazo-salts, due to the transposition, are, how- 
 ever, generally incapable of reactions. 
 
 ic. Secondary aromatic and aliphatic bases yield secondary 
 aromatic, or mixed aliphatic-aromatic, diazo-amido-compounds (B. 
 8, 148, 843 ; C. 1905, I. 1539). 
 
 2. Diazo-amido-compounds are also produced by the action of free 
 nitrous acid upon alcoholic solutions of free primary amines, the free 
 diazo-benzol hydrate or anhydride first formed turning into aniline : 
 
 C 6 H 5 N 2 .OH+NH 2 C 6 H 5 =C 6 H 5 N : N.NHC 6 H 5 +H 2 O. 
 
 If nitrites, such as silver nitrite, act upon free aniline, salts of the 
 diazo-amido-compounds are generated (B. 29, R. 1158). 
 
 3. A method specially useful for preparing mixed fatty-aromatic 
 diazo-amido-compounds is based upon the action of organo-magnesium 
 compounds upon the aryl esters of nitrogen hydride. Addition pro- 
 ducts containing Mg are first formed, and from these water liberates 
 the diazo-amido-compounds (D. 38, 683) : 
 
 /N 
 C 6 H 5 .N<^ i) + CH 3 .Mg.I = C 8 H 5 .N : N.N(MgI)CH 3 
 
 C fl H 5 N : N.N(MgI)CH 3 + H 2 O = C 6 H 5 N : N.NHCH 3 +MgI(OH). 
 
 4. Nitrosamines, and primary amines, also yield diazo-amido- 
 compounds (B. 27, 655). 
 
 Nitroso-acetanilide undergoes transposition with aniline, acetic 
 acid and diazo-amido-benzol being formed. If i mol. aniline is used 
 
134 ORGANIC CHEMISTRY 
 
 for every 2 mols. nitroso-acetanilide in an alkaline solution, an aro- 
 matic dis-diazo-amido-compound is obtained : 
 
 NO+NH a C e H 6 = C,H 6 NH N=NC 6 H 6 +CH 3 COOH 
 
 Course of the Reaction in the Formation of Diazo-amido-deriva- 
 tives. It is an interesting fact that the same diazo-benzol-p-amido- 
 toluol is formed, e.g., from diazo-benzol chloride and p-toluidin, as 
 from diazo-p-toluol chloride and aniline, although different com- 
 pounds might well have been expected : 
 
 C,H 6 N 2 Cl+NH 2 [ 4 ]C e H<[i]CH 3 - > I. C 6 H 5 N=N.NH[ 4 ]C 6 H 4 [i]CH 3 
 CH 3 [i]C a H 4 [ 4 ]N 2 Cl+NH 2 C e H 6 -- * II. CH 3 [i]C 6 H 4 [ 4 ]N==N.NHC 6 H 6 . 
 
 By method 3, the transposition of phenyl-azide with p-tolyl-mag- 
 nesium bromide, and of p-tolyl-azide with phenyl-magnesium bromide, 
 identical products are also obtained. 
 
 The constitution of the substances produced is best determined by 
 transposing them into phenyl iso-cyanate. Thus, diazo-benzol-p- 
 amido-toluol forms a urea with this reagent, and this new compound 
 will have either formula I'., corresponding to I., or II'., corresponding 
 to formula II., depending upon the constitution of the diazo-amido- 
 body : 
 
 NHC 6 H 5 
 
 I'. CO/ /[ 4 ]C 6 H 4 [i]CH 3 -- -CC<(NHCeH 5 +C(5 H 6 OH+N 2 
 
 XJN \ _ N=N.C H \NH[ 4 ]C 6 H 4 [i]CH 3 
 
 NHC 6 H 6 
 
 II'. C0<( /C 6 H 5 - 
 
 \N=N[ 4 ]C 6 H 4 [i]CH 3 
 
 On decomposing the urea with dilute sulphuric acid, the products 
 will be phenyl-p-tolyl-urea, phenol, and nitrogen ; whereas, accord- 
 ing to formula II'., they should be sym. diphenyl-urea, p-cresol, and 
 nitrogen. Therefore, diazo-benzol-amido-p- toluol is constituted ac- 
 cording to formula I. The imide group apparently combines with 
 the more negative radicle (B. 21, 2578 ; 40, 2395). 
 
 DlAZO-AMIDOCOMPOUNDS FROM PRIMARY AROMATIC BASES. 
 
 Diazo - benzol - amide, phenyl - triazene C 6 H 6 N : N.NH 2 , m.p. 50 
 with decomposition. Diazo-benzol-amide is the simplest conceivable 
 diazo-amido-compound. Its formation, by the action of ammonia 
 upon benzol-diazonium chloride, is not practicable, only dis-diazo- 
 benzol-amide being formed. It is obtained by reduction of diazo- 
 benzol-imide with stannous chloride and HC1 in ether at 18 : 
 
 C 6 H 6 N<(j|+2H=C 6 H 5 N : N.NH, 
 
 The cupro-salt forms yellow prismatic crystals. Diazo-benzol- 
 amide is exceedingly unstable. It decomposes spontaneously in a 
 short time, but instantly, in contact with acids, in aniline, and nitrogen. 
 
DIAZO-AMIDO-COMPOUNDS 135 
 
 It combines with phenyl iso-cyanate to form benzol-azo-phenyl-urea 
 C 6 H 5 N : N.NHCO.NHC 6 H 5 . Oxidisers like potassium hypobromite, 
 or ammoniacal silver solution, turn it into diazo-benzol-imide (B. 
 40, 2376). 
 
 Diazo - amido - benzol, benzol - diazo - anilide, diazo - benzol - anilide 
 (B. 14, 2443, footnote) C 6 H 5 .N 2 .NH.C 6 H 5 , melts at 96, and explodes 
 when it is heated to higher temperatures. It is obtained by the action 
 of nitrous acid on the cold alcoholic solution of aniline (Griess, A. 121, 
 2 58) ; by mixing diazo-benzol nitrate with aniline (B. 7, 1619) ; and 
 by pouring a slightly alkaline sodium nitrate solution upon aniline 
 hydro-chloride (B. 8, 1074) or sulphate with cold sodium nitrite (B. 
 17,641 ; 19, 1953; 20, 1581). 
 
 The combination of diazo-benzol-imide with phenyl-magnesium 
 bromide gives a salt of diazo-amido-benzol, of the formula C 6 H 5 N 2 N 
 (MgBr)C 6 H 5 , where it can be liberated by water (B. 36, 910). 
 
 Diazo-amido-benzol consists of golden-yellow, shining laminae or 
 prisms. It is insoluble in water, sparingly soluble in cold, but readily 
 in hot alcohol, ether and benzene. Its transpositions will be dis- 
 cussed later; the most remarkable one is its rearrangement into iso- 
 meric amido-azo-benzol. 
 
 Its salts are very unstable, although it forms a double salt, 
 (C 1 2H 11 N 3 .HCl) 2 .PtCl 4 , with hydrochloric acid and PtCl 4 . It crys- 
 tallises in reddish needles. When the alcoholic solution is mixed 
 with silver nitrate, the compound C 6 H 5 .N 2 NAg.C 6 H 5 separates in 
 reddish needles. 
 
 Sodium, in ethereal solution, converts it into C 6 H 5 NNaN==N.C 6 H 6 , 
 which is decomposed by water (B. 27, 2315). Cuprous salt, C. 1900, 
 
 I. 659. 
 
 Benzene-diazo-acetanilide C 6 H 5 N=N N(COCH 3 )C 6 H 5 melts with 
 decomposition at 130, and is formed when diazo-amidc-benzene 
 stands with acetic anhydride in toluene solution (B. 24, 4156). 
 
 The para-variety of the three diazo - amido - toluenes is alone 
 stable. The ortho- and meta-iorms (from ortho- and meta-toluidine) 
 immediately pass into isomeric amido-azo-derivatives. 
 
 Diazo - amido - compounds containing two different residues : 
 Mixed diazo-amidc-compounds, like Diazo-benzol-p-amido-bromc- 
 benzol, melting at 91 (B. 20, 3012). 
 
 o-, m-, p-Dinitro-diazo-amido-benzol, m.p. 196, 194, 228 (B. 
 27, 2201 ; 28, R. 303), diazo-benzol-p-amido-toluol, can be obtained 
 from the diazo-derivatives of the two components with the free amido- 
 derivatives e.g. Diazo-benzol-p-amido-toluol equally well from the 
 diazo-benzol salt with p-toluidin, as from p-diazo-toluol salt and 
 aniline. 
 
 Dis- diazo -benzol -amide (C 6 H 5 N : N) 2 NH (B. 27, 899) is ex- 
 tremely decomposable. Dis - diazo - benzol - anilide C 6 H 5 N=N N 
 (C 6 H 5 ) N=NC 6 H 5 consists of shining yellow flakes which explode 
 at 8o-8i in a capillary tube (B. 27, 703, 2597 ; C. 1905, 1. 517). 
 
 MIXED FATTY-AROMATIC DIAZO-AMIDC-COMPOUNDS. 
 
 Diazo - benzol - methyl-amide, methyl - phenyl - triazene C 6 H 5 N : N. 
 NHCH 3 , colourless plates, m.p. 37, obtained from diazo-benzol- 
 
136 ORGANIC CHEMISTRY 
 
 imide and methyl-magnesium iodide. With water vapour it volati- 
 lises without decomposition. With acids it is decomposed into ani- 
 line, nitrogen, and the ester of methyl-alcohol. With phenyl iso- 
 cyanate it forms a urea of m.p. 104, which is split, by HC1, into 
 benzol-diazonium chloride, and methyl-phenyl-urea. 
 
 Copper - methyl - phenyl - triazene C 6 H 5 N 3 CuCH 3 , orange - yellow 
 prisms, m.p. 187 with decomposition. 
 
 Acetyl-methyl-phenyl-triazene C 6 H 5 N : N.N(COCH 3 )CH 3 , m.p. 35 
 (B. 38, 678). Diazo-benzol-ethyl-amide, colourless crystals, m.p. 31. 
 p-Tolyl-methyl-triazene CH 3 C 6 H 4 N : N.NHCH 3 , m.p. 81-5 (B. 40,2397). 
 Diazo-benzol-dimethyl-amine C 6 H 5 N==N.N(CH 3 ) 2 , a yellowish oil (B. 
 8, 148). Diazo-benzol-piperidin C 6 H 5 N=N.NC 5 H 10 , m.p. 43. The 
 diazo-piperidins are useful for preparing fluorine compounds. 
 
 Benzol - azo - cyanamide, phenyl-cyano-triazene C 6 H 5 N : N.NHCN 
 or C 6 H 5 NH.N : N.CN, colourless flakes puffing off at 72. The potas- 
 sium salt is formed by heating diazo-benzol-imide with KCN in alcohol. 
 Acids split it up into diazo-benzol and urea : 
 
 C 6 H 5 N : N.NHCN+2H 2 O-C 6 H 5 N 2 OH+CO(NH 2 ) 2 . 
 
 Methylation of the potassium salt yields methyl-phenyl-cyano- 
 triazene C 6 H 5 (CH 3 )N.N : NCN, m.p. 6g-^o, decomposed by acids into 
 methyl-aniline, nitrogen, and cyanic acid (B. 37, 2374). 
 
 Dis- diazo-benzol- methyl -amine (C 6 H 5 N=N) 2 NCH 3 , light-yellow 
 needles, m.p. 112. Dis-diazo-benzol-ethyl-amine, m.p. 70 (B. 22, 
 934). 
 
 THE REARRANGEMENTS OF THE DIAZO-AMIDOCOMPOUNDS. 
 
 1. The most remarkable property of the diazo-amido-compounds, 
 containing a replaceable hydrogen atom in the p-position with refer- 
 ence to the NH group, is their ability to rearrange themselves into 
 isomeric p-amido-azo-derivatives. In the amido-azo-body the amido- 
 group holds the p-position with reference to the point of union : 
 
 C 6 H 5 N=N NHC 6 H 5 > C 6 H 5 N=N[i]C 6 H 4 [4]NH 2 . 
 
 This rearrangement completes itself in the course of a few days, 
 when a small quantity of an aniline salt is present. It may be 
 assumed that in the conversion a quantity of aniline, equal to that actu- 
 ally needed for the change, is produced ; consequently a comparatively 
 small amount of the aniline salt will be sufficient to rearrange a large 
 quantity of diazo-amido-benzol into amido-azo-benzol (Kekule, Z. f. 
 Ch. (1866), 689 ; B. 25, 1376). The rapidity of the conversion is 
 proportional to the strength of the acid whose aniline salt is employed 
 (B. 29, 1899). A strong base, such as amido-azo-benzol, is obtained 
 from a body indifferent to acids e.g. diazo-amido-benzol. Various 
 intramolecular atomic rearrangements, such as the preceding, in which 
 indifferent compounds are rearranged as strong bases or strong acids, 
 are known e.g. the rearrangement of hydrazo-benzol as benzidin, 
 of benzol into benzilic acid, etc. (I. 54 ; II. 116, 118). 
 
 2. The imide hydrogen of the diazo-amido-benzol can be replaced 
 by acid radicles, through the action of acid anhydrides (see Benzene- 
 diazo-acetanilide) . 
 
DIAZO-AMIDO-COMPOUNDS 137 
 
 3. The diazo-amido-compounds and phenyl iso-cyanate combine 
 with urea derivatives. 
 
 In the preceding reactions the diazo-amido-bodies are not decom- 
 posed. This occurs very readily (4) on treating them with con- 
 centrated haloid acids ; the diazo-amido-derivatives, like the diazo- 
 benzol salts, then change to haloid benzols ; the side products are 
 salts of the bases previously in combination with the diazo-residue. 
 Therefore the diazo-amido-compounds, in the presence of acids, are 
 fully converted by nitrous acid into diazo-benzol salts. This method 
 is not suitable for the determination of the constitution of unsym. 
 diazo-amido-compounds, since it is ambiguous. Thus, on treating 
 benzol-diazo-amido-p-toluol with dilute sulphuric acid, p-toluidin, 
 phenol, and p-cresol are formed. The behaviour of the diazo-amido- 
 bodies towards concentrated hydrofluoric acid, with the addition 
 of diazo-piperidins, proved itself particularly well adapted for the 
 preparation of fluoro-benzols (A. 243, 220) : 
 
 C 6 H 5 N=N.NC 5 H 10 +2HF1 = C 6 H 6 F1+N 2 +HF1.HNC 6 H 10 . 
 
 5. Boiling water converts the diazo-amido-compounds into phenols 
 and bases. 
 
 6. The reduction of the diazo-amido-bodies has not led to hydrazo- 
 amido-derivatives e.g. C 6 H 5 NH NH.NH.C 6 H 5 ; a decomposition into 
 phenyl-hydrazin and aniline has been the regular result. 
 
 7. On boiling the alcoholic solution with sulphurous acid, the diazo- 
 group is replaced by the sulpho-group : 
 
 C 6 H 5 N 2 NHC 6 H 5 +2S0 2 +2H 2 = C 6 H 6 SO3H+N,+C 6 H 5 NH 2 .SO 3 H 2 . 
 
 11. Diazo-oxy-amido-compounds. 
 
 These compounds are formed (i) from diazo-compounds with 
 j3-alkyl- and alphyl-hydroxylamines (cp. B. 32, 1546 ; A. 353, 228) ; 
 (2) from phenyl-hydrazins and nitroso-benzols, in the latter case with 
 liberation of hydrogen. If a-alkylated phenyl-hydrazins are used, 
 we get bodies like C 6 H 5 N(CH 3 )N^-^/NC,H 6 or C 8 H 5 N(CH 3 )N : N( : O)C a H 6 , 
 
 i.e. analogous to azoxy-compounds. 
 
 Diazo-oxy-amido-benzol C 6 H 5 N 2 .N(OH)C 6 H 5 , m.p. 127, yellowish 
 needles of silky lustre, from nitroso-benzol with phenyl-hydrazin, or 
 from diazo-benzol with phenyl-hydroxylamine. 
 
 Benzol-diazo-oxy-amido-methane C 6 H 5 N 2 .N(OH)CH 3 , m.p. 70, 
 from /3-methyl - hydroxylamine and diazo-benzol chloride (B. 30, 
 2278). Other compounds, see B. 32, 3554 ; C. 1909, II. 18. 
 
 12. Diazo-imido-compounds. 
 
 The diazo-imido-compounds are ethers of hydro-nitric acid 
 hydrazoic acid. They are produced : 
 
 i. By the action of aqueous ammonia upon diazo-benzol per- 
 bromides : 
 
 C,H 5 N 2 .Br 3 +NH 3 = 
 
138 ORGANIC CHEMISTRY 
 
 2. By the action of hydroxylamine upon diazo-benzol sulphate 
 (B. 25, 372 ; 26, 1271) : 
 
 C 6 H 5 N 2 OSO 3 H+NH 2 OH = C 6 H 5 N 3 +H 2 O+S0 4 H 2 . 
 
 The hydroxylamines can sometimes be replaced by the salts of 
 hydroxylamine-di-sulphonic acid (B. 33, 3408). 
 
 3. By the action of sodium nitrite upon the hydrochloric acid 
 solution of phenyl-hydrazin, when the nitroso-phenyl-hydrazins first 
 produced lose water and form phenyl-diazo-imides : 
 
 C ' H ' N< (NO = c H 
 
 4. From phenyl-hydrazin and diazo-benzol sulphate (B. 20, 1528 ; 
 21, 3415) : 
 
 C 6 H 5 NHNH 2 r H M /NH 2 r w V /N , r M TT 
 
 C^N 2 OS0 3 H ~ ' C H ' N \N : NC 6 H 5 " ' C 8 H 5 N<^ +C 6 H 5 NH 2 . 
 
 5. Hydrazin and diazo-benzol sulphate yield, on the one hand, 
 diazo-benzol-imide and ammonia; upon the other, aniline and azo- 
 imide or hydro-nitric acid, as by-products. These reactions are due 
 to the breaking down of a non-accessible intermediate product, 
 C 6 H 5 N=N NH.NH 2 (B. 26, 88, 1271) (cp. buzylene derivatives) : 
 
 NH 3 +C 6 H 5 N 3 < C 6 H 5 N : N.NH.NH 2 >C 6 H 5 NH 2 +N 3 H. 
 
 6. By the action of sodium hypochlorite upon j3-phenyl-semi- 
 carbazide, the latter being first oxidised to phenyl-azo-carboxyl-amide, 
 then transposed into diazo-benzol-amide, and finally converted into 
 diazo-benzol-imide : 
 
 /N 
 
 C 6 H 5 NH.NH.CONH 2 > C 6 H 5 N : N.CONH 2 > C 6 H 5 N : N.NH 2 > C 6 H 5 .N/ || 
 
 \N 
 
 Analogous reactions are given by a number of substituted phenyl- 
 semicarbazides (B. 40, 3035). 
 
 7. By oxidation of diazo-benzol-amide with potassium hypo- 
 bromite, or ammoniacal silver solution (B. 40, 2388). 
 
 Diazo-benzol-imide, phenyl-hydro-nitric ester C 6 H 5 N 3 , b.p. 59 (12 
 mm.), is a yellow oil with stupefying odour. It explodes at ordinary 
 pressures if heated. 
 
 o-, m-, and p-Nitro-diazo-benzol-imide NO 2 C 6 H 4 N 3 , m.p. 52, 55, 
 and 74. p-Bromo-diazo-benzol-imide, m.p. 20 (B. 33, 3409). 
 p-Amido-diazo-benzol-imide NH 2 C 6 H 4 N 3 , m.p. 62. p-Bis-triazo-benzol, 
 p-phenylene-bis-diazo-imide N 3 C 6 H 4 N 3 , light-yellow plates, m.p. 83, 
 formed from acetyl-p-phenylene-diamine by the reactions (C. 1906, 
 I. 1338) : 
 CH 3 CONHC 6 H 4 NH 2 > CH 3 CONHC 6 H 4 N 3 > NH 2 C tt H 4 N 3 > N 3 C 6 H 4 N 3 . 
 
 Transformations of the Diazo-benzol-imido-compounds. (i) On 
 
 boiling with HC1 they decompose into nitrogen and chloraniline 
 (B. 19, 313). (2) On boiling with H 2 SO 4 they split into nitrogen 
 and amido-phenols (B. 27, 192). (3) On boiling with alcoholic 
 potash the diazo-benzol-imido-compounds are partly split into nitro- 
 
AZOXY-COMPOUNDS 139 
 
 phenols and hydro-nitric acid (B. 25, 3328). (4) Heated by them- 
 selves, the ortho-nitrogenated diazo-imides are broken up into nitro- 
 gen and o-dinitro-benzols. (5) With methyl-magnesium iodide, and 
 phenyl-magnesium bromide, diazo-benzol-imide form salts of diazo- 
 amido- compounds, with splitting of the nitrogen ring. (6) With 
 KCN, diazo-benzol-imide combines to form phenyl-cyano-triazene. 
 
 (7) It combines additively with acetylene-dicarboxylic ester ; with 
 j3-ketone-carboxylic ester, as well as malonic esters, it combines to 
 form five-membered heterocyclic ring-systems, of the triazol group, 
 water or alcohol being set free : 
 
 CH 2 COOR _ N /N - CCOOR H Q 
 + COCH 3 \N(C 6 H 5 ) .CCH 3 
 
 (8) By condensation of diazo-benzol-imide with benzaldehyde-aryl- 
 hydrazones, tetrazones are formed (B. 40, 2402), e.g. : 
 
 C 6 H 6 N<^||+C,H 5 NH.N:CHC 8 H 5 = 
 
 13. Azoxy-compounds. 
 
 Formation. (i) By reduction of nitro- and nitroso-compounds 
 with methyl or ethyl alcoholic potash solutions (B. 26, 269) : 
 
 4 C 6 H 5 N0 2 + 3 HCH 2 ONa == 2(C 6 H 5 N) 2 O+3HCO 2 Na+ 3 H 2 O. 
 
 Sodium amalgam and alcohol, zinc dust in alcoholic ammonia, and 
 arsenious acid in alkaline solution (B. 28, R. 125) reduce nitro-bodies 
 to azoxy-compounds. 
 
 (2) By the oxidation of amido- and azo-derivatives (Z. f. Ch. 1866, 
 309 ; B. 6, 557 ; 18, 1420 ; 36, 3805), as well as by the spontaneous 
 oxidation of jS-phenyl-hydroxylamine in the air. Nitroso-benzol is 
 formed intermediately, and combines with unchanged /?-phenyl- 
 hydroxylamine to form azoxy-benzol (see Steric hindrance) . 
 
 Behaviour. (i) When reduced by heating with iron filings they 
 yield azo-compounds ; with ammonium sulphide, hydrazo-derivatives ; 
 and with acid reducing agents, amido-bodies, resulting from the de- 
 composition and rearrangement of the hydrazo-compounds first pro- 
 duced. (2) Their rearrangement into oxy-azo-compounds, on digest- 
 ing them with concentrated sulphuric acid, is interesting (Wallach and 
 Belli, B. 13, 525). 
 
 XX 
 
 Azoxy-benzol, azoxy-benzide c,H 5 N^- -*N C 8 H 5 , m.p. 36, forms 
 long yellow needles, easily soluble in alcohol and ether, but not in 
 water. It melts at 36, and decomposes into azo-benzol and aniline 
 when distilled. It is converted into p-oxy-azo-benzol by digestion 
 with concentrated sulphuric acid, besides yielding other products 
 (C. 1903, I. 324, 1082). 
 
 Concerning an isomeric azoxy-benzol, m.p. 84, formed as a 
 by-product of the reduction of nitroso-benzol with alcoholic soda solu- 
 tion, see B. 42, 1364. 
 
 Benzene and H 2 C1 6 , acting on azoxy-benzol, give benzene-azo- 
 diphenyl C 6 H 5 N 2 C 6 H 4 .C 6 H 5 and diphenyl-azo-diphenyl (C. 1904, I. 
 1491). 
 
140 ORGANIC CHEMISTRY 
 
 o- and p-Nitro-azoxy-benzol, m.p. 49 and 149. The o-compound 
 on reduction gives phenyl-azo-nitroso- and phenyl-azo-amido-benzol (B. 
 32, 3262). Sym. o 2 -dinitro-azoxy-benzol, m.p. 175 (B. 36, 3813). 
 Sym. p 2 -dinitro-azoxy-benzol, m.p. 192, by oxidation of p 2 -dinitro- 
 azo-benzol. Sym. m-dinitro-azoxy-benzol, m.p. 141, from m-di- 
 nitro-benzol (B. 25, 608 ; 38, 4013). Sym. m-diamido-azoxy-benzol, 
 azoxy-aniline, m.p. 147 (B. 29, R. 137). p-Tetramethyl-diamido- 
 azoxy-benzol, m.p. 243, from nitroso-dimethyl-aniline. Trinitro- 
 azoxy-benzols, from azoxy-benzol (B. 23, R. 104), o-, m-,and p-Azoxy- 
 toluol, m.p. 59, 38, and 70. 
 
 14. Azo-compounds. 
 
 Like the diazo-derivatives, these contain a group consisting of 
 two nitrogen atoms ; in the former the N 2 group is combined with only 
 one benzene nucleus and an inorganic residue ; here it is attached on 
 either side to benzene nuclei, or to a benzene nucleus and an aliphatic 
 radicle : 
 
 C 8 H 5 N = N C e H 5 C 6 H 6 N =N CH 3 
 
 Azo-benzol Benzol azo-methane. 
 
 In consequence, they are far more stable than the former, and do 
 not react with the elimination of nitrogen. 
 
 Intermediate links between diazo- and azo-compounds are re- 
 presented by the diazo-benzol cyanides, the benzol-azo-carboxylic 
 derivatives, etc. 
 
 Classification and Nomenclature. The true aromatic azo-bodies 
 are distinguished as symmetrical, those in which the two residues are 
 the same, and unsymmetrical, those in which the two residues are dis- 
 similar. Mixed azo-bodies are those in which the azo-group joins an 
 aromatic to an aliphatic radicle. 
 
 The names of the unsymmetrical azo-bodies are derived from the 
 names of the two bodies in which the azo-group has replaced an atom 
 of hydrogen each, separated by the word azo, thus : C 6 H 5 N=N 
 C 6 H 4 N(CH 3 ) 2 , benzol-azo-dimethyl-aniline ; C 6 H 6 N=N CH 3 , ben- 
 zol-azo-methane. Should the benzene residues contain substituents, 
 the positions in the one residue are indicated by numbers i to 6, and 
 in the second residue by numbers i' to 6', with the understanding 
 that the azo-group occupies the i, I'-position. Dis-azo- and tris-azo- 
 compounds, containing two or three azo-groups, are known (B. 15, 
 2812). 
 
 Formation. i. By the moderated reduction of nitro-bodies in 
 alkaline solution, because in acid solution the final reduction products 
 of nitro-bodies, the amido-derivatives, are almost invariably produced. 
 Azoxy-compounds are first formed, but by further reduction they 
 pass into azo-derivatives. The reducing agents are : 
 
 (a) Zinc dust in alcoholic potash or soda (B. 21, 3139), or in 
 ammonia. 
 
 (b) Sodium or magnesium amalgam and alcohol (C. 1904, II. 1383). 
 
 (c) Stannous chloride in sodium hydroxide (B. 18, 2912). 
 
 Also (d) the electrolytic reduction of nitro-derivatives to azo-bodies 
 (C. 1898, II. 775 ; 1900, I. 1175 ; 1901, II. 153). 
 
AZO-COMPOUNDS 141 
 
 By more complete reduction hydrazo-bodies are formed, along with 
 the azo-derivatives ; these can eventually be decomposed into amido- 
 compounds. Azo-benzol is the middle member in the series of reduc- 
 tion products obtained from nitro-benzol, if j8-phenyl-hydroxylamine 
 is not taken into consideration : 
 
 Nitro-benzol Azoxy-benzol Azo-benzol Hydrazo -benzol Aniline. 
 
 2. By reduction of azoxy-compounds on heating them with iron 
 filings. 
 
 3. By the oxidation (a) of hydrazo-bodies, and (b) of primary 
 amido-derivatives in alkaline solution. This takes place in air alone 
 (B. 42, 2938), and more easily by means of potassium permanganate 
 (A. 142, 364), potassium ferricyanide or sodium hypobromite (B. 
 39, 744). 
 
 4. By the action of nitroso-benzol upon aniline. 
 
 5. By the rearrangement of certain diazo-amido-bodies into amido- 
 azo-derivatives. 
 
 6. By the transposition of certain diazo-amido-compounds into 
 azo-amido-compounds. 
 
 7. By action of diazo-salts (a) upon tertiary anilines ; (b) upon 
 m-diamines ; and (c) upon phenols. 
 
 The last two methods lead to amido-derivatives of the azo-hydro- 
 carbons, some of which have become very important in the coal-tar 
 colour industry. 
 
 Mixed azo-derivatives are frequently obtained by combining diazo- 
 salts with suitable fatty bodies, i.e. such as contain easily replace- 
 able hydrogen atoms in union with carbon, or with heterocyclic com- 
 pounds like pyrrol, pyrazol, etc. 
 
 Properties. The azo-bodies are more intensely coloured than the 
 pale-yellow azoxy-derivatives. They unite with acids with great 
 difficulty unless they contain an additional basic amido-group. They 
 can be directly chlorinated, nitrated, and sulphonated. Reducing 
 agents convert them into hydrazo-compounds, or decompose them at 
 the point of double union, with the production of amido-compounds. 
 The latter reaction serves to determine the constitution of the amido- 
 azo-derivatives. 
 
 INDIFFERENT, SYMMETRICAL AZO-COMPOUNDS. Azo-benzol, azo- 
 benzide C 6 H 5 N=NC 6 H 5 , m.p. 68 and b.p. 293, was discovered by 
 Mitscherlich in 1834. It forms orange-red, rhombic crystals, readily 
 soluble in alcohol and ether, but sparingly soluble in water. It is 
 produced by the methods outlined above from nitro-benzol, aniline, 
 and hydro-benzol. Azoxy-benzol yields it on distillation with iron 
 filings (B. 207, 329). It has also been obtained from potassium aniline 
 by action of air, and from aniline and sodium (B. 10, 1802). It is 
 converted into benzidin by tin and hydrochloric acid ; this is due to a 
 transposition of the hydrazo-benzol first formed. 
 
 HC1 in methyl-alcohol solution produces a fundamental change in 
 azo-benzol, reduction and chlorination taking place simultaneously 
 (A. 367, 304). With benzol-sulphinic acid it combines to form phenyl- 
 
142 ORGANIC CHEMISTRY 
 
 sulphone-hydrazo-benzol. On heating with CS 2 mercapto-thiazol is 
 produced (B. 24, 1403). 
 
 Nitration of azo-benzol easily produces nitro-azoxy-benzols. o-, 
 m-, and p-Nitro-azo-benzol, m.p. 71, 96, and 135, are obtained by 
 transformation of the three nitro-nitroso-benzols with aniline, or of 
 the three nitranilines with nitroso-benzol (B. 36, 3811, 3818). 2, 4- 
 Dinitro-benzol-azo-benzol, m.p. 117, by oxidation of the hydrazo- 
 benzol. m 2 - and p 2 -Dinitro-azo-benzol, m.p. 153 and 221. Trinitro- 
 azo-benzols (B. 32, 3256). Sym. hexa-nitro-azo-benzol, m.p. 215 
 (B. 41, 1297). 
 
 Reduction of o-nitro-azo-compounds produces phenyl-azimide 
 oxides and phenyl-pseudo-azimides (q.v.) (B. 36, 3822). 
 
 Azo-toluols. o-Azo-toluol melts at 157. m-Azo-toluol melts at 
 55, and p-azo-toluol at 143 (B. 17, 463 ; 18, 2551). Azoxylenes and 
 azo-trimethyl-benzols are known. 
 
 MIXED AZO-COMPOUNDS. Benzol-azo-methane, azo-phenyl-methane 
 C 6 H 5 N=NCH 3 , b.p. about 150, andBenzol-azo-ethaneC 6 H 5 .N=NCH 2 . 
 CH 3 , b.p. about 180, are liquids with a peculiar odour. They are 
 obtained by oxidising the corresponding hydrazins with mercuric 
 oxide. Sulphuric acid transposes benzol-azo-ethane into the isomeric 
 acetaldehyde-phenyl-hydrazone C 6 HsNH.N : CH.CH 3 (B. 29, 794 ; 
 36, 56). With amyl nitrite, and sodium alcoholate, both benzol-azo- 
 ethane and acetaldehyde-phenyl-hydrazone give benzol-azo-acet-ald- 
 oxime C 6 H 5 N : NC(NOH)CH 3 . In compounds of the type : 
 
 ArN : NC(NOH)R or ArNH.N : C(NO)R 
 ArN : NC(NOOH)R or ArNHN : C(NO 2 )R 
 
 the desmotropic relations between azo- and hydrazone forms are closer 
 than in the simple mixed azo-bodies. These classes of bodies, desig- 
 nated as benzol-azo-aldoximes or nitroso-phenyl-hydrazones, and benzol- 
 azo-nitronic acids or nitro-phenyl-hydrazones, respectively, are dealt 
 with below, in connection with the related amidrazones and formazyl 
 compounds. 
 
 Mixed azo-compounds are also produced by combination of diazo- 
 salts and substances with a reactive CH 2 group. Thus we obtain 
 benzol-azo-aceto-acetic ester with desmotropic hydrazone forms of 
 the type C 6 H 5 .NHN : C(COCH 3 )(COOR). Concerning the structure 
 of benzol-azo-amino-crotonic ester, see B. 35, 1862. 
 
 Certain other bodies may also be regarded as mixed azo-com- 
 pounds : Benzol-diazo-carboxylic acids and their derivatives the diazo- 
 cyanides, diphenyl-sulpho-carbazone and carbo-diazone, benzoyl-diazo- 
 benzol (q.v.), and numerous azo-bodies produced by combination of 
 diazo-salts with heterocyclic compounds like pyrrol, pyrazol, etc. 
 
 AMIDO-AZO-COMPOUNDS. The indifferent azo-derivatives are all 
 orange-yellow to orange-red in colour, but they are not dyes. By 
 the introduction of amino- or HO groups in ortho- or para-position to 
 the azo-group the resulting bodies, like o- and p-amido-azo-com- 
 pounds, oxy-azo-compounds, and especially amido-azo-benzol-sul- 
 phonic acids, do become colours applicable in the dyeing of wool and 
 silk (B. 35, 4225). The number of azo-dyes is very great. Some of 
 the simplest will be discussed in the following paragraphs, while the 
 most important representatives of the class, technically speaking, 
 
AZO-COMPOUNDS 143 
 
 will be considered in other portions of this book, particularly in con- 
 nection with the naphthalene group. The sulphonic acids of the amido- 
 azo-bodies are of greater importance than the parent substances. 
 
 Formation. i. From diazo-amido - compounds : p-amido-azo- 
 benzol is obtained from diazo-amido-benzol. In the case of diazo- 
 amido-benzol this transposition occurs on standing with alcohol, but 
 more readily by the action of a slight quantity of aniline chloro- 
 hydrate. 
 
 This reaction only occurs readily if, in the reacting diazo-amido- 
 compound, the position hi the benzol nucleus adjacent to the amido- 
 group in the para place be unoccupied. 
 
 However, compounds, like diazo-amido-p-toluol CH 3 [4]C 6 H 4 [i]N : 
 N [i']NHC 6 H 4 [4']CH3, in which the p-position with reference to the 
 imido-group is occupied by CH 3 , also suffer this transposition. It 
 occurs on heating diazo-amido-p-toluol, dissolved in fused p-toluidin, 
 to 65 with p-toluidin. 
 
 The amido-group of the resulting amido-azo-toluol occupies the 
 o-position with reference to the diazo-group. It is o-amido-azo-toluol 
 or [$-methyl-benzol-azo-[^'}-methyl-[2 r ]-amido-benzol CH 3 [4]C 6 H 4 [i]N : 
 N[i']C 6 H 3 [ 4 ']CH 3 [ 2 ']NH 2 (B. 17, 77). 
 
 2. By the action of the diazo-compounds (a) upon the tertiary 
 aromatic amines, or (b) upon m-diamines in neutral, or feebly acid, 
 solution (B. 10, 389, 654) : 
 
 C 6 H 6 .N S N0 3 +C 6 H 5 N(CH 3 ) 2 = C,H 6 .N : N.[i]C,H 4 [ 4 ]N(CH 3 ) 2 +NO 3 H 
 
 The first products with primary and secondary monamines, especi- 
 ally in neutral or acetic acid solution (B. 24, 2077), are diazo-amido- 
 compounds, which, under the previously mentioned conditions, are 
 capable of rearranging themselves into amido-azo-derivatives. 
 
 But in the formation of diazo-amido-compounds from diazonium 
 salts and nucleus-substituted anilines the isomeric amido-azo-com- 
 pounds usually occur as by-products, and only become chief products 
 in meta-substitutions, e.g. m-toluidin (/. pr. Ch. 2, 65, 401). 
 
 The phenols act like the tertiary amines upon diazo-salts with 
 the formation of oxy-azo-derivatives, which will be discussed later 
 after the amido-phenols. 
 
 Properties and Behaviour. The amido-azo-compounds are usually 
 crystalline, and generally dissolve readily in alcohol. They are yellow, 
 red, or brown in colour. With acids they form two isomeric series of 
 salts : yellow unstable, and violet stable salts. The former are 
 produced by the action of a defective quantity of acid upon amido- 
 compounds, and easily pass into the darker isomeric salts by excess 
 of acid, pressure, heat, etc. The dark salts are probably salts of 
 the quinone-imide-hydrazone C 6 H 5 NHN : C 6 H 4 : NH.HC1, and form 
 the industrial amido-azo-dyes (B. 41, 1171). 
 
 (i) Their decomposition upon reduction, and the great importance 
 of this reaction, have been previously dwelt upon (B. 21, 3471 ; 
 C. 1908, 1. 721). Occasionally decomposition, such as this, takes place 
 on heating the bodies with hydrochloric acid (B. 17, 395). If titanium 
 trichloride is employed, the reduction splitting can be used for the 
 
144 ORGANIC CHEMISTRY 
 
 volumetric estimation of the dyes (B. 36, 1552). (2) Amido-azo- 
 compounds may be changed to diazo-azo-derivatives with nitrous acid. 
 Iso-dihydro-phene-tetrazins may be obtained by reducing the diazo-salts 
 of o-amido-azo-derivatives. (3) Indulins (q.v.) are produced on heat- 
 ing p-amido-azo-compounds with aniline hydrochloride, and eurhodins 
 when o-amido-azo-bodies are employed. (4) When the o-amido-azo- 
 compounds are oxidised they become pseudo-azimido-denva.tives. (5) 
 The o-amido-azo-compounds combine with aldehydes. Condensation 
 products result, which are derived from dihydro-pheno-triazin (q.v.). 
 
 p-Amido-azo-benzol C 6 H 5 .N : N(i]CH 4 i4]NH^ yellow flakes or 
 needles, m.p. 127, b.p. 12 . 225, boils without decomposition even at 
 ordinary pressures. It can be obtained from p-nitro-azo-benzol, and is 
 prepared industrially by transposition of diazo-amido-benzol (B. 19, 
 1953 ; 21, 1633). MnO 2 and sulphuric acid oxidise it to quinone ; 
 reduction splits it into aniline and p-phenylene-diamine. With HC1 
 it forms a bright-yellow and a deep-violet chlorohydrate. The latter 
 was, like the oxalate, formerly used as a yellow dye. In the coal-tar 
 industry it is used on a large scale as a fundamental material for ob- 
 taining diazo-dyes and indulins. While the salts of amido-azo-benzol 
 are unimportant as dyes, the sulpho-acids, " acid yellow " or " real 
 yellow," have valuable properties. 
 
 p-Aeetamido-azo-benzol, m.p. 143. Benzol-azo-phenyl-cyanamide 
 C 6 H 5 N : NC 6 H 4 NHCN, m.p. 163, obtained by the action of diazo- 
 benzol chloride upon sodium cyano - aniline (C. 1906, II. 1054). 
 Benzol-azo-phenyl-glyein C 6 H 5 N : NC 6 H 4 NHCH 2 COOH, m.p. 140, 
 obtained from phenyl - glycin |and benzol - diazonium chloride (B. 
 35, 580). For further acidyl derivatives of p-amido-azo-benzol, 
 see B. 35, 1431 ; C. 1902, II. 360. m-Amido-azo-benzol C 6 H 5 N 2 [i] 
 C 6 H 4 [3]NH 2 , m.p. 57; its aceto-compound, m.p. 131, has been ob- 
 tained from nitroso-benzol and aceto-m-phenylene-diamine (B. 28, 
 R. 982). Benzol-azo-p-dimethyl-aniline C 6 H 5 N : N[i]C 6 H 4 [4]N(CH 3 ) 2 , 
 m.p. 116. p - Azo - benzol - trimethyl - ammonium iodide C 6 H 5 N : 
 NC 6 H 4 N(CH 3 ) 3 I, m.p. 185, obtained from benzol-azo-dimethyl-aniline 
 with methyl iodide. Unlike the corresponding primary and tertiary 
 amine salts, it does not dye wool and silk (A. 345, 303). Benzol-azo- 
 diphenyl-amine, p-anilido-azo-benzol, m.p. 82. o-Amido-azo-toluol 
 CH 3 [2]C 6 H 4 [i]N :N[i']C 6 H 3 [3 / ,4'](CH 3 )NH 2 , m.p. 100, from o-tolui- 
 din. m-Amido-azo-toluol CH 3 [ 3 ]C 6 H 4 [i]N : N[i']C 6 H 3 [2',4'](CH 3 )NH 2 , 
 m.p. 80. m-Nitro-benzol-azo-p-amido-benzol, m.p. 213 (B. 29, 
 R. 661). 
 
 2, 4-Diamido-azo-benzol C 6 H 5 N 2 C 6 H 3 (NH 2 ) 2 , m.p. 117, small 
 yellow needles, obtained from diazo-benzol nitrate and m-phenylene- 
 diamine. Its HC1 salt occurs in commerce under the name chryso'idin, 
 and dyes orange-red. On reduction it splits into aniline and unsym. 
 triamido-benzol C 6 H 3 (NH 2 ) 3 . 
 
 Sym. o 2 -Diamido-azo-benzol H 2 N.C 6 H 4 .N 2 .C 6 H 4 NH 2 , copper-red 
 flakes, m.p. 134, obtained by gentle oxidation of o-phenylene-diamine, 
 with polymerisation of the o-quinone-di-imine first formed (B. 38, 2348). 
 The di-acetyl compound, m.p. 271, is also obtained by reduction of 
 o-nitro-acetanilide (B. 39, 4062). 
 
 The sym. p 2 -Diamido-azo-benzol H 2 N.C 6 H 4 .N 2 .C 6 H 4 .NH 2 has been 
 obtained from nitro-acetanilide N0 2 .C 6 H 4 .NH.C 2 H 3 O by reduction 
 
AZO-COMPOUNDS 145 
 
 with zinc dust and alkali, and from the diazo-compound of mono-ace to- 
 phenylene-diamine, with aniline (B. 18, 1145) ; also by reduction of 
 p 2 -dinitro-azo-benzol (B. 18, R. 628). It crystallises from alcohol in 
 yellow needles, and melts at 241. 
 
 The tetra-alkyl derivatives of p 2 -diamido-azo-benzol form the so- 
 called " azylins," first obtained by the action of nitric oxide upon 
 dialkyl-aniline (B. 16, 2768) : 
 
 2C 6 H 5 .NR 2 .R 2 N.C 6 H 4 .N 2 .C 6 H 4 .NR 2 . 
 
 Also by the action of the diazo-compounds of dimethyl-p-phenylene- 
 diamine upon tertiary anilines (B. 18, 1143). The azylins are red, 
 basic dyes, soluble in HC1 with purple coloration, and in acetic acid 
 with emerald-green coloration. By reduction with stannous chloride, 
 or with tin and HC1, they are split into two molecules of dialkyl-p-pheny- 
 lene-diamine. By heating with alkyl iodides (4 mol.) to 100 they are 
 also split up, forming tetra-alkylised para-phenylene-diamine. 
 
 mnii-Diamido-azo-benzol, m.p. 155, and Tetra-methyl-mnij-di- 
 amido-azo-benzol, m.p. 118, obtained from m-nitraniline and m- 
 nitro-dimethyl-aniline by reduction with zinc dust and alkali. In 
 contrast with the o- and p-amido-azo-bodies, they are very feeble dyes 
 (B. 35, 4225). 
 
 3, 2', 4'-Tri-amido-azo-benzol c 12 H 13 N 5 =H 2 N.C 8 H 4 .N 2 .c,H 3 /^2 2 ' m -P- 
 
 \.N Jcij 
 
 144, is best obtained from m - amido - phenylene - oxaminic acid 
 NH 2 [i]C 6 H 4 [3]NH.CO.COOH by diazotising, combining with m- 
 phenylene-diamine, and saponincation. The action of nitrous acid 
 upon m-phenylene-diamine itself produces a mixture of bases contain- 
 ing, besides tri-amido-azo-benzol, chiefly Phenylene-disazo-m-pheny- 
 lene-diamine C 6 H 4 [N 2 C 6 H 3 (NH 2 )2] 2 , m.p. ii6-ii8. The chlorides 
 of this mixture of bases form the commercial phenylene brown, Bis- 
 marck brown, Vesuvine, or Manchester brown, which serves for dyeing 
 cotton and leather (cp. B. 30, 2203 ; 31, 188). 
 
 15. Hydrazin Compounds. 
 
 The simplest aromatic hydrazin derivatives are : Phenyl-hydrazin 
 CeH 5 .NH.NH 2 ; unsym. diphenyl-hydrazin (C 6 H 5 ) 2 N.NH 2 , and sym. 
 diphenyl-hydrazin C 6 H 5 NH.NH.C 6 H 5 , or hydrazo-benzol. 
 
 Phenyl-hydrazin and unsym. diphenyl-hydrazin both contain an 
 NH 2 group. They show similar reactions in many respects, whereas 
 the symmetrical diphenyl-hydrazin deports itself rather peculiarly. In 
 the following paragraphs sym. diphenyl-hydrazin and its homologues, 
 the hydrazo-compounds, the hydrazin derivatives longest known, will be 
 placed at the head of the aromatic hydrazins. The hydrazo-compounds 
 arrange themselves with the previously discussed azo-bodies, with which 
 they possess genetic connections. Then will follow the mono-phenyl- 
 and the unsym. diphenyl-hydrazin group. 
 
 Hydrazc-compounds. Symmetrical diphenyl-hydrazin was dis- 
 covered in 1863 by A. W. Hofmann upon reducing azo-benzol with care, 
 and, inasmuch as it differed from the last compound in containing two 
 hydrogen atoms more, it was called hydrazo-benzol, a name which has 
 adhered to symmetrical diphenyl-hydrazin. 
 
 VOL. II. L 
 
146 ORGANIC CHEMISTRY 
 
 Formation. Azo-benzol and allied compounds yield hydrazo-benzo, 
 upon reducing them with alcoholic ammonium sulphide, with zinc dust, 
 and with potassium or sodium amalgam. It is not necessary to isolate 
 the azo-body ; the proper nitro- and azoxy-derivatives can be treated 
 with zinc dust and sodium hydroxide. Nitro-compounds can also be 
 converted in alkaline solution into hydrazo-derivatives by electrolytic 
 reduction (Ch. Ztg. 17, 129, 209 ; C. 1898, II. 775). 
 
 Hydrazo-benzol, sym. diphenyl-hydrazin C 6 H 5 NH.NHC 6 H 5 , m.p. 
 131, decomposes at higher temperatures ; also on heating with alcohol 
 to 120 130 in azo-benzol and aniline. It forms colourless flakes or 
 plates, insoluble in water, but easily soluble in alcohol and ether. It 
 smells somewhat like camphor, and oxidises spontaneously in moist 
 air, or in alcoholic solution, to azo-benzol, giving off H 2 O 2 , especially 
 in the presence of alkali (B. 33, 476 ; A. 316, 331). Hydrazo-benzol 
 is an indifferent body, forming no salts with mineral acids, but under- 
 going remarkable intramolecular atomic displacements (see Benzidin 
 and semidin transposition, below). Strong reducing agents split up 
 hydrazo-benzol into 2 mol. aniline. With nitro-benzol it transposes 
 itself to azo-benzol and j8-phenyl-hydroxylamine (B. 33, 3508). 
 
 With phenyl iso-cyanate (B. 23, 490) and phenyl-mustard oil (B. 
 25, 3115) hydro-benzol gives urea derivatives ; with aldehydes it gives 
 various reactions : formaldehyde gives CH 2 (C 6 H 5 N.NHC 6 H 5 ) 2 and 
 
 aldehyde oxidises hydrazo-benzol to azo-benzol (/. pr. Ch. 2, 65, 97). 
 On heating with CS 2 it yields sulpho-carbanilide and sulphur (B. 36, 
 
 3841). 
 
 Mono-acetyl-hydrazo-benzol, m.p. 159, decomposes at higher tem- 
 peratures into azo-benzol and acetanilide. Di-acetyl-hydrazo-benzol, 
 m.p. 105 (B. 17, 379; A. 207, 327). Further acetyl derivatives, see 
 B. 31, 3241 ; C. 1903, II. 359. 
 
 o-, m-, p-Methyl-hydrazo-benzol or sym. o-, m-, p-Tolyl-phenyl- 
 hydrazin melt at 101, 60, and 86. 
 
 Sym. hydrazo-toluols CH 3 C 6 H 4 NH.NHC 6 H 4 CH 3 : o-compound, 
 m.p. 165 ; m-compound, liquid (A. 207, 116) ; p-compound, m.p. 128 
 (B. 9, 829). Hydrazo-xylols (B. 21, 3141). 
 
 Sym. di-halogen-substituted hydrazo-benzols are obtained from 
 the corresponding azo-compounds. p-Diamido-hydrazo-benzol, di- 
 phenin NH 2 [ 4 ]C 6 H 4 [i]NH.NH[i']C 6 H 4 [4']NH 2 , m.p. 145, from p- 
 dinitro-azo-benzol with AmS 2 (B. 18, 1136). 
 
 Unsym. nitro-hydrazo-benzols have been obtained by reduction 
 of nitro-azo- and nitro-azoxy-compounds, and also from chloro-dinitro- 
 and chloro-trinitro-benzol with phenyl-hydrazin (A. 190, 132 ; 253, 2 ; 
 /. pr. Ch. 2, 37, 345 ; 44, 67 ; B. 32, 3280 ; C. 1902, II. 41). Sym. 
 hexanitro-hydrazo-benzol, black crystals of metallic lustre, m.p. 201, 
 from picryl chloride and hydrazin (B. 41, 1295). 
 
 THE BENZIDIN AND SEMIDIN TRANSPOSITION OF THE 
 HYDRAZO-COMPOUNDS. 
 
 Hydrazo-benzol undergoes a very remarkable rearrangement into 
 an isomeric compound when it is treated with acids. When azo-benzol 
 
TRANSPOSITION OF THE HYDRAZO-COMPOUNDS 147 
 
 is reduced in acid solution, the hydrazo-benzol which is produced does 
 not form salts, but even in the cold is changed by mere contact with 
 acids into a diamine, a diacid base : benzidin (q.v.) or p-diamido-di- 
 phenyl. Benzidin, a fundamental substance for the preparation of 
 substantive cotton dyes, is prepared technically in this way. Di- 
 phenylin, an o-, p-diamido-diphenyl, occurs in small quantities besides 
 benzidin (B. 17, 1181) : 
 
 C 8 H 4 [ 4 ]NH, _ C 6 H 6 NH _ C,H 4 [ 4 ]NH t 
 
 C 8 H 4 [ 4 ]NH, CH 5 ttH C fl H 4 [2]NH, 
 
 Benzidin Hydrazo-benzol Diphenylin. 
 
 The chief transposition, in which the two amido-groups take up 
 a para-position with respect to the junction of the two benzene nuclei, 
 is called the benzidin transposition of the hydrazo-compounds. 
 
 The transposition is best effected by means of mineral acids, but 
 benzidin, in the shape of its acidyl compounds, is also obtained from 
 hydro-azo-benzol by boiling with formic, or acetic, acids (B. 35, 1433). 
 
 Sym. o- and m-ditolyl-hydrazin or o- and m-hydrazo- toluol, as well 
 as other hydrazo-compounds in which the p-hydrogen atoms of the 
 imido-groups are free in both aromatic residues, yield with mineral 
 acids the corresponding p-diamido-ditolyls or tolidins, etc. 
 
 If, however, p-hydrazo-toluol be treated with aqueous mineral acids, 
 it changes in part to p-azo-toluol and p-toluidin, and partly to o-amido- 
 ditolyl-amine (B. 27, 2700). The latter body is principally formed by 
 the action of stannous chloride and hydrochloric acid upon hydrazo- 
 toluol : 
 
 CH 3 f HN-NH || CH 3 - -> CH 3 |f NH |gj H. 
 
 p-Hydrazo-toluene o-Amido-[ 4 , s'J-ditolyl-amine. 
 
 This is the semidin transposition ; it is so called because only the 
 one NH group is converted into an NH 2 group, and not both NH 
 groups, as in the benzidin transposition. In simple p-substituted 
 hydrazo-benzols the amido-group can enter the o- or p-position with 
 reference to the imido-group. Hence it is necessary to distinguish 
 between an o- and p-semidin transposition. 
 
 Often these transpositions take place side by side, so that the 
 semidin bases are obtained together with the diphenyl bases. Treated 
 with HC1 gas in benzene, hydrazo-benzol yields also small quantities 
 of o-amido-diphenyl-amine (Ch. Ztg. 18, 1095) : 
 
 With stannous chloride and HC1, p-acetamido-hydrazo-benzol 
 passes into aceto-p-diamido-diphenyl-amine : 
 
 C,H 3 O.NH -2 NH.NH g-g H - > C a H 3 O.NH g-g NH S^ NH a . 
 
 When a substituent occupies the para-position in hydrazo-benzol, 
 the benzidin transposition takes place with separation of this sub- 
 stituent. Thus, benzidin is produced by p-chloro-hydrazo-benzol and 
 p-hydrazo-benzol-carboxylic acid. Concerning the influence of the 
 substituents upon the transposition, see A. 369, i. 
 
148 ORGANIC CHEMISTRY 
 
 We may here make a brief survey of the transposition in which 
 anilines substituted for the nitrogen become nucleus-substituted ani- 
 lines, by a wandering of the substituents ; this generally leads to a 
 stronger basicity. These transpositions are : (i) that of phenyl-nitros- 
 amines into p-nitroso-anilines (see above) ; (2) of phenyl-nitramines 
 (diazo-benzolic acids) into p-nitraniline ; (3) of j3-phenyl-hydroxylamines 
 into p-amido-phenols ; (4) of phenyl-hydrazins into p-phenylene- 
 diamines ; (5) of chloryl-anilines into p-chloranilines ; (6) of diazo- 
 amides into p-amido-azo-bodies ; (7) of hydrazo-benzols into benzidins 
 and amido-diphenyl-amines, the formulae being : 
 
 1. C 6 H 5 N(CH 3 )NO ->ONC 6 H 4 NHCH 3 5. C 6 H 5 NHC1 -- >C1C 6 H 4 NH 2 
 
 2. C 6 H 6 NH.N0 2 - >0 2 NC 6 H 4 NH 2 6. C 6 H 5 NH(N 2 C 6 H 5 ) ->(C 6 H 5 N 2 ).C 6 H 4 NH 2 
 
 3. C 6 H 5 NH(OH) - ^HOC 6 H 4 NH 2 xrTTNHr w |-*NH 2 C 6 H 4 .C 6 H 4 NH 2 
 
 4. C 6 H 5 NH(NH 2 ) - ^NH 2 C 6 H 4 NH 2 7 ' ^^ LC n *- 
 
 To these are added a number of reactions in which carbon groups 
 wander from nitrogen to the nucleus. Thus we have the transposition 
 of phenyl-alkylamines into homologous anilines, of diacetanilide into 
 acetamino-aceto-phenone, etc. ; also the transpositions of phenyl- 
 sulphaminic acid into o- and p-anilino-sulphonic acid, of phenyl-sul- 
 phuric acid, and phenyl-carbonic acid, into phenyl-sulphonic acid, 
 and salicylic acid, respectively, as well as o-azo-compounds into oxy- 
 azo-compounds (q.v.). 
 
 Phenyl-hydrazin Group. Phenyl-hydrazin and unsym. di phenyl- 
 hydrazin are formed in the reduction of diazo-benzol salts and diphenyl- 
 nitrosamine, as well as from the reaction products formed when nitrous 
 acid acts upon primary and secondary anilines : 
 
 I C 6 H 5 NH 2 HC1 -- >C 6 H 5 N : N.C1 -- >C 6 H 5 NHNH 2 HC1 
 i (C 6 H 5 ) 2 NH -- >(C 6 H 5 ) 2 N.NO -- >(C 6 H 5 ) 2 N.NH 2 . 
 
 Formation. i. By the reduction of diazo-salts : (a) By the action 
 of acid alkaline sulphites upon the diazo-derivatives. On allowing 
 acid potassium sulphite to act upon the yellow potassium salt of diazo- 
 benzol-sulphonic acid, colourless potassium phenyl-hydrazin sulphonate 
 is formed : 
 
 C 6 H 5 N=N SO 3 K+SO 3 HK+H 2 O = C 6 H 5 NH.NHSO 3 K + SO 4 KH. 
 
 When the sulphonate is heated with concentrated hydrochloric acid, 
 phenyl-hydrazin chlorohydrate is produced, together with primary 
 potassium sulphate : 
 
 C 6 H 5 .N 2 .H 2 .S0 3 K+HC1+H 2 = = C 6 H 5 .N 2 H 3 .HC1+SO 4 KH. 
 
 The sulphazides e.g. C 6 H 5 .NH.NH.SO 2 .C 6 H 5 , phenyl-benzene sulph- 
 azide, or C 6 H 5 N :NC 6 H 4 N 2 H 2 S0 3 H, azo-benzol-p-hydrazin-sulphonic 
 acid are prepared by the action of free sulphurous acid upon the acid 
 solution of diazo-benzene salts. 
 
 p-Nitro-diazo-benzol nitrate and two molecules of potassium sul- 
 phite yield potassium p-nitro-phenyl-hydrazin disulphonate, C 6 H 4 
 (NO 2 )N(SO 3 K)NH(SO 3 K), which hydrochloric acid decomposes quanti- 
 tatively into p-nitro-phenyl-hydrazin. 
 
 In the same manner dipotassium sulphite changes potassium ben- 
 
PHENYL-HYDRAZIN GROUP 149 
 
 zene-diazo-sulphonate into potassium phenyl-hydrazin disulphonate, 
 C 6 H 5 N(SO 3 K)NH(SO 3 K), which can be more easily obtained from 
 nitroso-acetanilide and dipotassium sulphite. It is resolved by hydro- 
 chloric acid into phenyl-hydrazin and sulphuric acid, and decomposed 
 by alkali into potassium benzene-diazo-sulphonate (B. 30, 374). 
 
 (b) Potassium diazo-benzene sulphonate can be reduced with acetic 
 acid and zinc dust. 
 
 (c) By the action of stannous chloride and hydrochloric acid upon 
 the diazonium chlorides (B. 16, 2976 ; 17, 572) : 
 
 C 6 H 5 .N 2 Cl+2SnCl 2 +4HCl = C 6 H 5 .N 2 H 3 .HCl+2SnCl 4 . 
 
 Diazo- and iso-diazo-benzol-alkali salts, when reduced with sodium 
 amalgam, yield phenyl-hydrazin (B. 30, 339). 
 
 2. Diazo-amido-bodies are reduced by zinc dust and acetic acid in 
 alcoholic solution, and split into anilines and hydrazins : 
 
 C 6 H 5 N 2 .NH.C 6 H 5 + 2 H 2 == C 6 H 5 .N 2 H 3 + NH 2 .C 6 H 5 
 
 Diazo-amido-benzol Phenyl-hydrazin Aniline. 
 
 3. Nitrosamines, reduced by zinc dust and acetic acid, give unsym. 
 alkyl-phenyl- or diphenyl-hydrazins ; aliphatic hydrazins (Vol. I.) 
 have been similarly obtained : 
 
 Diphenyl-nitroso-amine a-Diphenyl-hydrazin . 
 
 Historical. A. Strecker and Romer (1871), on treating diazo-benzol 
 nitrate with acid potassium sulphite, obtained potassium phenyl- 
 hydrazin sulphonate C 6 H 5 NH.NHSO 3 K, and, on subjecting the 
 diazide of sulphanilic acid to the same treatment, a soluble potassium 
 salt, which, on boiling with HC1, yielded crystallising phenyl-hydrazin- 
 
 . , . , r> TT NH 2 ,, f. 
 
 p-sulphonic acid C 6 H 4 ^j : * H 2 , the first pnmary aromatic 
 
 hydrazin compound. In 1875 Emil Fischer showed how to convert 
 this body into phenyl-hydrazin chlorohydrate by boiling with HC1, 
 and how to obtain, by means of alkaline hydroxide, the free phenyl- 
 hydrazin, a body exceedingly capable of transposition (B. 8, 589). 
 
 Properties. The aromatic hydrazins are mono-acid bases, almost 
 insoluble in water, but easily soluble in alcohol and ether. They boil 
 at ordinary pressures with slight decomposition, and under low 
 pressures without decomposition. In air they oxidise easily, assuming 
 a brown coloration (C. 1907, II. 1067). They reduce Fehling's 
 solution. 
 
 PHENYL-HYDRAZIN C 6 H 5 NH NH 2 , flat crystals, m.p. 19-6, 
 b.p. 24i-242, b.p. 12 120. Density at 21, 1-091. Obtained by 
 reduction of benzol-diazonium chloride. Also, in small quantities, on 
 heating hydrazin hydrate with phenol to 220 (B. 31, 2909). Its trans- 
 positions are described below. As one of the generators of antipyrin 
 it has attained importance in industry, and it also serves as a reagent 
 for aldehydes and ketones. This latter use is of special importance in 
 the chemistry of hydrocarbons. 
 
 Phenyl-hydrazin ehlorohydrate C 6 H 5 NH.NH 2 HC1, brilliant white 
 flakes, slightly soluble in concentrated HC1, yields p-phenylene-diamine 
 
150 ORGANIC CHEMISTRY 
 
 on heating to 200 with HC1. Carboxylates, see B. 27, 1521. Sodium 
 phenyl-hydrazin C 6 H 5 NNa.NH 2 , obtained by dissolving sodium in 
 phenyl-hydrazin. It forms a reddish-yellow, amorphous mass, which, 
 with halogen alkyls and haloids, forms the so-called a-phenyl-hydrazin 
 derivatives (B. 19, 2448 ; 22, R. 664). 
 
 POTASSIUM PHENYL-HYDRAZIN (B. 20, 47). 
 
 SUBSTITUTED PHENYL-HYDRAZINS (A. 248, 94 ; B. 22, 2801, 2809).- 
 p-Chloro-phenyl-hydrazin, m.p. 83. p-Bromo-phenyl-hydrazin, m.p. 
 106. p-Iodo-phenyl-hydrazin, m.p. 103. o-Nitro-phenyl-hydrazin, 
 m.p. 90, brick-red needles (B. 27, 2549). o-Nitro-s-formyl-phenyl- 
 hydrazid, m.p. 177 (B. 22, 2804). 
 
 For hetero-ring formation from these o-nitro-compounds, see below. 
 
 p-Nitro-phenyl-hydrazin, m.p. 157, is often useful for separating 
 and characterising aldehydes and ketones (B. 32, 1806). 2, <\-Dinitro- 
 phenyl-hydrazin, yellow prisms, m.p. 197, from dinitro-bromo-benzol 
 and hydrazin hydrate (C. 1908, I. 125). 
 
 HOMOLOGOUS PHENYL-HYDRAZINS.- o-Tolyl-hydrazin, m.p. 59. 
 m-Tolyl-hydrazin, liquid, p - Tolyl - hydrazin, m.p. 61. p-Xylyl- 
 hydrazin, m.p. 78. Pseudo-eumyl-hydrazin (A. 212, 338 ; B. 18, 3175 ; 
 22, 834 ; C. 1905, II. 40). 
 
 Unsym. diphenyl-hydrazin (C 6 H 5 ) 2 N.NH 2 , m.p. 34, b.p. 50 220, 
 obtained by reduction of diphenyl-nitrosamine, forms, with glucose, 
 diphenyl-hydrazones, soluble with difficulty. By oxidation with 
 ferric chloride it passes into tetraphenyl-tetrazone. 
 
 Triphenyl-hydrazin (C 6 H 5 ) 2 N.NHC 6 H 5 , obtained by the action of 
 phenyl - magnesium bromide upon j8 - phenyl - hydroxylamine. By 
 alcoholic HC1 it is transposed into N-phenyl-benzidin C 6 H 5 NH.C 6 H 4 . 
 C 6 H 4 .NH 2 (B. 40, 2099). 
 
 Tetraphenyl-hydrazin (C 6 H 5 ) 2 N.N(C 6 H 5 ) 2 , m.p. 144, by oxidation 
 of diphenyl-amine with MnO 4 K or PbO 2 ; also from sodium diphenyl- 
 amine (C 6 H 5 ) 2 N.Na with iodine (B. 39, 1501). It dissolves in concen- 
 trated H 2 SO 4 with a deep-blue colour, being partly transposed into 
 NN'-diphenyl-benzidin C 6 H 5 NH.C 6 H 4 .C 6 H 4 .NHC 6 H 5 (cp. C. 1907, I. 
 406). HC1 splits it into diphenyl-amine and p-chloraniline-triphenyi- 
 amine, a reaction in which diphenyl-chloramine (C 6 H 5 ) 2 NC1 must be 
 assumed as an intermediate product (B. 41, 3508). 
 
 Tetra-p-tolyl-hydrazin (CH 3 .C 6 H 4 ) 2 N.N(C 6 H 4 CH 3 ) 2 , m.p. 136, by 
 oxidation of p-ditolyl-amine with MnO 4 K, and by heating tetra-p-tolyl- 
 tetrazone. It combines with acids, halogens, metalloid and metallic 
 chlorides like PC1 5 , SbCl 3 , SnCl 4 , etc., to form deep-violet addition 
 products, resembling salts, from which water regenerates the unchanged 
 hydrazin. In neutral solvents these partly very unstable compounds 
 soon decompose to form p-ditolyl-amine, and derivatives of ditolyl- 
 hydroxylamine (CH 3 C 6 H 4 ) 2 NOH, which, however, undergo an imme- 
 diate further change, with formation of derivatives of di-tertiary 
 dihydro-phenazin (B. 41, 3478). 
 
 Behaviour of the Phenyl-hydrazins. (i) While the phenyl-hydrazins 
 are pretty stable towards reducing agents, they may be readily recon- 
 verted into diazo-compounds by moderate oxidation ; this is effected 
 by the action of mercuric oxide upon their sulphates or sulphonates. 
 
 When boiled with copper sulphate, ferric chloride, potassium 
 chromate, Caro's acid, or sodium hypochlorite (C. 1909, II. 596), the 
 
BEHAVIOUR OF THE PHENYL-HYDRAZINS 151 
 
 phenyl-hydrazins throw off nitrogen and become benzols this reaction 
 will also serve for the replacement of the diazo-group by hydrogen and 
 by the halogens if the free phenyl-hydrazin be replaced by chlorine, 
 bromine, or iodine (B. 18, 90, 786 ; 25, 1074 C. 1908, II. 1022). The 
 liberated nitrogen also answers for the quantitative estimation of the 
 hydrazins. 
 
 The phenyl-hydrazins also reduce Fehling's solution (B. 26, R. 234). 
 Consult B. 28, R. 996 ; 29, R. 977, for additional reduction reactions 
 with phenyl-hydrazin. 
 
 (2) Sodium liberates hydrogen, and a-sodium phenyl-hydrazins 
 result. 
 
 (3) Nitrous acid converts the phenyl-hydrazins into nitroso- 
 hydrazins. 
 
 (4) Halogen alkyls replace the imido- and amido-hydrogen of the 
 phenyl-hydrazins, and eventually form phenyl-hydrazonium compounds. 
 
 (5) Acid radicles may also thus be easily introduced into phenyl- 
 hydrazins. 
 
 (6) Chlorine and bromine, at low temperatures, convert the primary 
 phenyl-hydrazins into the corresponding diazonium salts. At higher 
 temperatures, and in the presence of mineral acids, we get halogen 
 phenyl-hydrazins with nuclear substitution (C. 1908, I. 2149 ; 1909, 
 
 II. 595). 
 
 (7) The aldehydes and ketones combine with the phenyl-hydrazins, 
 usually with the immediate separation of water and formation of phenyl- 
 hydrazones. This reaction, like the oxime formation, is characteristic 
 of the aldehydes and ketones. 
 
 (8) When the phenyl-hydrazins are heated to 200 with fuming 
 hydrochloric acid, they are transposed into para-phenylene-diamines 
 (B. 28, 1538). 
 
 PHENYL-ALKYL-HYDRAZINS. The unsymmetrical compounds, with 
 an alkyl residue, are called " a "-compounds, and the symmetrical ones 
 " j3 "-compounds. 
 
 Modes of Formation. (i) Both isomers are generated by the action 
 of alkyl bromides upon phenyl-hydrazin (A. 199, 325 ; B. 17, 2844). 
 The isolation of the ^-compounds is based upon their capacity of passing 
 into azo-compounds by oxidation with HgO. These, owing to their 
 volatility, and their indifference towards acids, can easily be separated 
 from the other products, and can then be converted by reduction back 
 into the original jS-alkyl-phenyl-hydrazins. The a-compounds are 
 formed (2) by the action of alkyl bromides upon sodium-phenyl- 
 hydrazin (B. 19, 2450 ; 22, R. 664) ; (3) by the reduction of the corre- 
 sponding nitrosamines with zinc dust ; (4) by treatment of /?-aceto- 
 phenyl-hydrazin C 6 H 5 NH.NHCOCH 3 with halogen compounds, and 
 saponification with boiling dilute acids (B. 26, 946). 
 
 a-Methyl-phenyl-hydrazin C 6 H 5 N(CH 3 )NH 2 , b.p. 35 131, by trans- 
 position gives methyl-p-phenylene-diamine. a-Ethyl-phenyl-hydrazin 
 C 6 H 5 N(C 2 H 5 )NH 2 , b.p. 237. Both compounds on oxidation give 
 tetrazone (qv.). The ethyl compound combines with ethyl bromide 
 to form Diethyl-phenyl-hydrazonium bromide C 6 H 5 N(C 2 H 5 ) 2 BrNH 2 , 
 which, on reduction, gives diethyl-aniline. 
 
 a-Propyl-, a-Isopropyl-, a-Isobutyl-, a-Isoamyl-phenyl-hydrazin 
 boil at 247, 236, 245, 262 (B. 30, 2809). a-d-Amyl-phenyl-hydrazin 
 
152 ORGANIC CHEMISTRY 
 
 CH3 \CH.CH 2 N(C 8 H 5 ).NH 2 , b.p. 50 I73-I75, has been used for the direct 
 
 C 2 H 5 / 
 
 splitting up of racemic aldehydes and ketones (B. 38, 868). 
 
 Ethylene-phenyl-hydrazin C 6 H 5 N(NH 2 )C 2 H 4 .N(NH 2 )C 6 H 5 , m.p. 90 
 (B. 21, 3203 ; A. 310, 156). Unsym. o-Amido-phenyl-methyl- 
 hydrazin NH 2 [2]C 6 H 4 [i]N(CH 3 )NH 2 , an easily resinified oil, is produced 
 from nitro-nitroso-methyl-aniline by reduction with alcoholic Am 2 S. 
 
 HETERO-RING FORMATIONS OF O-SUBSTITUTED PHENYL-HYDRAZINS. 
 On boiling with an alkaline hydrate, o-nitro-phenyl-hydrazin passes 
 into azimidol (q-v.). The formyl compound of o-nitro-phenyl-hydrazin 
 yields a-pheno-triazin on reduction with sodium amalgam and acetic 
 acid. The unsym. o-amido-phenyl-methyl-hydrazin, when treated 
 with HNO 2 , passes into pheno-methyl-hydro-tetrazin : 
 
 Azimidol 
 [ 2 ]N(OH) 
 
 r /[ijNH.NHCHO H /[i]N=N 
 
 CeH4 \ [2]N0 2 CeH4 \ [2]N=CH a-Pheno-triazm 
 
 c H f[i]N(CH 3 ).NH 2 NOQH c H r[i]N(CH 3 ).N Pheno-methyl- 
 
 4 \[2]NH 2 4 \[2]NH N dihydro-tetrazin. 
 
 )8-Methyl- and j8-ethyl-phenyl-hydrazin are colourless oils, oxidising, 
 in air, to benzol-azo-methane and -ethane, from which they can be 
 recovered by reduction. j3-Methyl-phenyl-hydrazin is also obtained 
 from antipyrin (q.v.) by boiling with alcoholic potash (B. 39, 3265). 
 jS-Alkyl-phenyl-hydrazin, b.p. 110 177 (B. 22, 2233). 
 
 Di- and tri-alkylated phenyl-hydrazins are prepared from the sodium 
 compound of a-methyl-phenyl-formyl-hydrazin C 6 H 5 N(CH 3 )N.NaCHO 
 with alkylene iodide, the formyl group being detached by means of 
 fuming hydrochloric acid. The dialkylated phenyl-hydrazins, under 
 the action of alkylene iodide, give rise to quaternary azonium compounds, 
 e.g. C 6 H 5 N(CH 3 ) 2 I.NH.CH 3 , besides trialkyl-phenyl-hydrazins. a-j8- 
 Dimethyl-phenyl-hydrazin C 6 H 5 N(CH 3 ).NH.CH 3 , b.p. 93; a, j8-Dl- 
 ethyl-phenyl-hydrazin C 6 H 5 N(C 2 H 5 )NHC 2 H 5 , b.p. u in -ii5, are 
 produced by the action of zinc methyl and zinc ethyl upon benzol- 
 diazonium chloride (B. 35, 4179). Phenyl-trimethyl-hydrazin, b.p. 8 93 
 (B. 27, 696). 
 
 PHENYL-HYDRAZONE AND OSAZONE. As the aldehydes and ketones 
 yield oximes with hydroxylamines, so with phenyl-hydrazin they pass 
 into phenyl-hydrazones. The compounds derived from the aldehydes 
 are also called " aldehydrazones " (A. 247, 194, footnote), the ketone 
 derivatives " keto-hydrazones," and the dihydrazones of the a-dicarbonyl 
 compounds " osazones " (B. 21, 984 ; 41, 73) : 
 
 R'.CHO+NH 2 NHC 6 H 5 = R'.CH : N.NHC 6 H 5 +H 2 O 
 (R') 2 CO+NH 2 NHC 6 H 5 = (R') 2 C : N.NHC 6 H 5 +H 2 O. 
 
 The osazones are also formed from the a-oxy-aldehydes and a-oxy- 
 ketones, hydrazones being formed first, in which the alcohol group, 
 adjoining the aldehyde, or keto, group, is oxidised by the excess of 
 phenyl-hydrazin to a CO group : 
 
 RCHOH.CHO+3C 6 H 5 NH.NH 2 = RC( : N.NHC 6 H 6 )CH : N.NHC 6 H 5 
 
 +C 6 H 5 NH 2 +NH 3 . 
 
PHENYL-HYDRAZONE 153 
 
 The formation of osazones has acquired a special importance in 
 the chemistry of sugars (Vol. I.). 
 
 Of the phenyl-hydrazones, of the aldehydes and ketones, numerous 
 isomeric forms have been discovered, and their occurrence is, as in the 
 case of the oximes, attributed to a cis-trans-isomerism. The first 
 isomeric osazones were found in 1895, through the action of phenyl- 
 hydrazin upon dioxo-succinic ester (Vol. I.), three forms being dis- 
 covered (B. 28, 64). But no definite evidence as to configuration 
 resulted. 
 
 The monoximes of a-aldehyde-ketones and a-diketones, treated 
 with phenyl-hydrazin, yield hydrazoximes. Thus, from methyl- 
 glyoxalic oxime we obtain methyl-glyoxal-oxime : Methyl-glyoxal- 
 phenyl-hydrazoxime CH 3 C(: NNHC 6 H 5 )CH : NOH, m.p. 134 (A. 
 262, 278). 
 
 When phenyl-hydrazones are formed, an addition product is prob- 
 ably first generated, corresponding, in its constitution, to ammonia 
 aldehyde. In a few cases, e.g. those of oxalic acid ester and dioxo- 
 succinic ester, addition products have been identified, which easily 
 pass into phenyl-hydrazones with elimination of water : 
 
 C0 2 C 2 H 5 .CO CO,C 2 H 5 C/^J -NHC 6 H 5 
 
 I +NH 2 NHC a H 5 = | X OH 
 
 C0 2 C 2 H 6 .CH 2 C0 2 C 2 H 6 CH 2 
 
 /NH NHC 6 H 5 
 
 C0 2 C 2 H 6 .CO C0 2 C 2 H 6 C< x oH 
 
 C0 2 C 8 H 5 .CO -> IC * H * = cOX,H 5 i/ NH NHC e H 5- 
 
 The fact that dioxo-succinic ester gives an addition compound tells 
 in favour of the ammonia-aldehyde view, and against the ammonium- 
 salt view, suggested by the case of oxalic ester (A. 295, 339). Phenyl- 
 hydrazin-p-sulphonic acid seems only to yield addition products of 
 the formula RCH(OH)NHNHC 6 H 4 SO 3 H with the aldehydes (B. 
 35, 2000). 
 
 Since the phenyl-hydrazones are characteristic of the corresponding 
 compounds containing aldehyde and ketone groups, they had to be 
 repeatedly mentioned, in advance, in dealing with aliphatic compounds, 
 and we shall deal with them again in connection with the aromatic 
 compounds in which aldehyde and ketone groups are present. It 
 seems, however, advisable to refer briefly to the aliphatic phenyl- 
 hydrazone derivatives. The following have received mention in the 
 first volume of this work : Phenyl-hydrazones of the simple aldehydes ; 
 of the simple ketones ; of the diketones ; of glyoxylic acid ; of pyro- 
 racemic acid ; of aceto-acetic ester ; of laevulinic acid ; of mesoxal- 
 aldehyde ; of acetone-oxalic ester ; of mesoxalic acid ; of oxal-acetic 
 ester ; of acetone-dicarboxylic ester ; of acetone-diacetic acid ; of 
 tetroses ; of oxalyl-diacetone ; of dioxo-succinic acid ; of oxalo- 
 succinic ester ; of arabinose ; of rhamnose ; of the glucoses ; of milk 
 sugar ; of maltose and isomaltose. 
 
 Formation of the Phenyl-hydrazones. (i) By the action of phenyl- 
 hydrazin and unsym. alkyl-phenyl- or unsym. diphenyl-hydrazin 
 upon aldehydes and ketones (see above). (2) By the addition of phenyl- 
 hydrazin to trebly linked carbon atoms ; the phenyl-hydrazone of 
 
154 ORGANIC CHEMISTRY 
 
 oxaloacetic ester is also produced by the addition of phenyl-hydrazin 
 to acetylene-dicarboxylic ester : 
 
 C0 2 .C 2 H 5 .C CO a .C 2 H 6 .C=N.NH.C 8 H 5 
 
 |||+NH 2 NHC 6 H 8 = 
 CO 2 .C 2 H 6 .C CO 2 .C 2 H 6 .CH a 
 
 (3) By the interaction of diazo-benzol salts and many aliphatic bodies, 
 containing hydrogen atoms readily replaceable by alkali metals e.g. 
 malonic ester and aceto-acetic ester : 
 
 (C0 2 C 2 H 6 ) 2 CH 2 +C 6 H 5 N 2 OH = (CO 2 C 2 H 6 ) 2 C=N NH.C 8 H 5 +H 2 O 
 
 Phenyl-hydrazone-mesoxalo-ester 
 
 Phenyl-hydrazone-aceto-glyoxylib ester. 
 
 The examination of desmotropic forms, in which the enol- and the 
 keto-forms can be isolated, has shown that only the former reacts 
 with diazonium salts. We must therefore assume that, in all cases, 
 the azo group tackles the enol hydroxyl, forming 0-azo-compounds, 
 which transpose themselves into C-azo-compounds and then into 
 phenyl-hydrazones (B. 41, 4012). In some cases (see Tribenzoyl- 
 methane) the isolation of the various intermediate products has been 
 accomplished. 
 
 The body obtained from malonic ester with diazo-benzol hydrate is 
 identical with that obtained from mesoxalic ester and phenyl-hydrazin. 
 For the compound obtained from acetic acid ester, and diazo-benzol 
 salts, we may have to replace the hydrazone formula C 6 H 5 NHN : 
 C(COCH 3 )CO 2 C 2 H 5 by the desmotropic formula of a benzol-azo-aceto- 
 acetic ester C 6 H 5 N : N.CH(COCH 3 )CO 2 C 2 H 5 , since in dilute sodium 
 hydrate the ester dissolves into a salt from which CO 2 precipitates the 
 ester without change a behaviour which is best explained by the 
 presence of one of the mobile H atoms of the aceto-acetic ester (B. 32, 
 197 ; A. 312, 128). On the other hand, benzol-azo-aceto-acetic ester 
 is converted into the hydrazone of pyro-racemic aldehyde by saponin- 
 cation and liberation of CO 2 . This involves a transposition, for the 
 pyro-racemic aldehydrazone, treated with chloro-acetic ester and 
 sodium ethylate, yields an ester which, on reduction, yields anilido- 
 acetic acid. The latter is only possible if the residue of the chloro- 
 acetic acid was connected with the N atom to which the phenyl group 
 had been attached (A. 247, 190). 
 
 The product of the combination of cyanacetic ester and diazo- 
 benzol salts occurs in two forms the a-form, m.p. 125, and the jS-form, 
 m.p. 85, which are regarded as stereo-isomeric hydrazone forms 
 C 6 H 5 NH.N : C(CN)COOR. Alkali easily converts the -form into the 
 a-form (B. 88, 2266). Glutaconic ester (Vol. I.) reacts with 2 mol. 
 of diazo-benzol salts, with formation of compounds containing the 
 phenyl -hydrazone group as well as the azo -group CO 2 R.C : 
 (N.NHC 6 H 5 ).CH : C.(N : NC 6 H 5 )CO 2 R (B. 40, 4928). Concerning the 
 constitution of the reaction products of diazo-benzol salts upon amino- 
 crotonic ester, etc., see B. 36, 1449. 
 
 The tendency towards the formation of phenyl-hydrazones is so 
 
TRANSFORMATIONS OF THE PHENYL-HYDRAZONES 155 
 
 great that CO 2 is split off from alkyl-aceto-acetic acids by diazo-benzol 
 chloride, with formation of the phenyl-hydrazone of an a-diketone ; 
 and from alkyl aceto-acetic esters, with elimination of the acetyl 
 group, phenyl-hydrazones of a-ketone-carboxylic esters are formed : 
 
 CH 3 .CH.C0 2 H CH 3 .C : N.NHC 6 H 6 
 
 CH 3 .CO -CH 5 N 2 C1 = CH3( , .0 2 + 
 
 Diacetyl-phenyl-hydrazone (Vol. I.) 
 
 CH 3 .CH.CO,C 2 H 5 ri_i_TT n ^ 
 
 CH 3 .CO -C 6 H 5 N,C1 H 2 
 
 Phenyl-hy drazone -pyro-racemic ester. 
 
 From malonic acid and diazo-benzol chloride, also, glyoxylic 
 phenyl-hydrazone is formed and CO 2 split off (C. 1905, I. 1538). On 
 rales of rejection of acidyl groups from di-acidyl-acetic esters by diazo- 
 benzol salts, see B. 35, 915. The latter act like HNO 2 , which produces 
 oximes under similar conditions (Vol. I.). 
 
 Transformations of the Phenyl-hydrazones. On heating the 
 phenyl-hydrazones with dilute mineral acids they break up into their 
 progenitors. By careful reduction many phenyl-hydrazones have been 
 converted into phenyl-hydrazido-compounds (B. 28, 1223 ; 30, 736 ; 
 C. 1899, I- S^o)- The phenyl-hydrazones often unite with HCN even 
 more easily than do aldehydes and ketones to form cyano-hydrins, or 
 nitriles of a-phenyl-hydrazido-carboxylic acids (B. 33, 3550). 
 
 Very few classes of organic compounds are capable of entering into 
 the formation of heterocyclic bodies to the extent manifested by the 
 hydrazin derivatives, whose intramolecular condensation reactions 
 are, therefore, of the utmost importance in the development of the 
 chemistry of ring-systems containing nitrogen. Some of the most 
 important condensations have been met with in connection with the 
 phenyl-hydrazones of the fatty compounds, and will be again given in 
 condensed form, while others will receive mention at the conclusion 
 of the acid hydrazides. 
 
 1. Indols result upon heating the phenyl-hydrazones of aldehydes, 
 ketones, and ketonic acids with zinc chloride, stannous chloride, or 
 mineral acids. 
 
 2. Pyrazolins result from the transposition of the phenyl-hydra- 
 zones of a-olefin aldehydes and ketones. 
 
 3. Oso-tetrazones are produced when the osazones or a-diphenyl- 
 hydrazones of a-dialdhydes, a-aldehyde-ketones, and a-diketones are 
 oxidised. 
 
 4. Boiling acids change the a-osazones and oso-tetrazones to oso- 
 triazoles, 
 
 5. Dehydrating agents convert a-hydrazoximes into oso-triazoles. 
 
 6. Pyrazoles result from the phenyl-hydrazones of the i, 3-oxy- 
 methylene ketones, and j3-diketones, by the exit of water ; they are 
 ring-shaped nitrogen derivatives of the i, 3-olefin ketones. 
 
 7. The phenyl-hydrazones of i, 4-diketones rearrange themselves 
 into n-anilido-pyrrols. 
 
 In preparing ring-shaped condensation products of the hydrazones 
 the latter have frequently not been isolated, but simply worked 
 over. 
 
156 
 
 ORGANIC CHEMISTRY 
 
 The following scheme represents the hetero-ring-formations possible 
 with the phenyl-hydrazones : 
 
 CH 3 .C=N NHC 6 H 6 
 
 CH 3 
 
 CH=N NHC 6 H 5 
 
 CH=N NHC 6 H 6 
 CH 3 .C=N NC 8 H 5 
 
 CH 3 .C=N NC 6 H 5 
 
 CH 3 .C=N NH.C 6 H 5 X CH 3 .( 
 
 .C -I 
 
 CH 3 .C NH V 
 
 II >C 6 H 4 
 
 CH_ 
 CH=N NC C H 5 
 
 CH=N NC 6 H 5 
 
 NC 6 H 5 
 
 o-Methyl-indol, or methyl- 
 ketol 
 
 Glyoxal-osotetrazone 
 
 Diaceto-ostriazone, or 
 n-phenyl-dimethyl- 
 osotriazole 
 
 CH 
 
 -N OH 
 
 CH 3 .C N N, i-Phenyl-3-methyl-pyra- 
 
 CH 3 .CO +NH a NHC,H 8 X I ru / NH 6 C 5 Z ole 
 S L/rl=UJrl 
 
 CH=CHOH \ CH=^N X 
 
 )>N.C 6 H 5 i -Phenyl-5-methyl-pyra- 
 
 CH 3 .CO 
 
 CH 2 CO 
 
 + NH 2 NHC,H 5 
 
 CH 3 
 CH 3 
 
 CH 2 . CO +NH.NHC.H, 
 
 CH 2 . CO 
 
 CH 3 
 
 J H=:C / >N ' C6H5 i-Phenyl-3, 5-dimethyl- 
 x pyrazole 
 
 CH 3 
 CH 3 
 / 
 i \-VT -Mur^ TT n-Anilido-a-dimethyl- 
 
 CH^C/ p> rrro1 - 
 
 CH 5 
 
 PHENYL-HYDRAZIN DERIVATIVES OF INORGANIC ACIDS. Thionyl- 
 phenyl-hydrazone C 6 H 5 NH.N=SO, melting at 105, consists of 
 sulphur-yellow coloured prisms. It is obtained, like the thionyl- 
 alkylamines and thionyl-anilines, by the interaction of thionyl chloride 
 and phenyl-hydrazin. All phenyl-hydrazins having a free amido-group 
 yield thionyl-phenyl-hydrazones when acted upon with thionyl chloride 
 (B. 27, 2549) Thionyl-phenyl-hydrazone is more easily produced when 
 thionyl-aniline acts upon phenyl-hydrazin. Further, it results upon 
 gently digesting phenyl-hydrazin-sulphinic acid C 6 H 5 NH.NH.SOOH, 
 obtained from sulphur dioxide and phenyl-hydrazin (B. 23, 474). 
 Thionyl chloride, acetyl chloride, and other acid chlorides rearrange 
 thionyl-phenyl-hydrazin into diazo-benzol chloride, in that it reacts as if 
 it were diazo-benzol sulphoxide C 6 H 5 N=N.S(OH) (A. 270, 114). 
 
 Phenyl-hydrazin-sulphonic acid C 6 H 5 NH.NH.SO 3 H. The potas- 
 sium salt is formed in the reduction of potassium benzene-diazo-sul- 
 phonate with sulphuric acid or monalkaii sulphites. For the behaviour 
 of the potassium salt towards mineral acids, and the role it plays in the 
 history of the discovery of phenyl-hydrazin, see above. 
 
 p - Nitro - phenyl - hydrazin - disulphonic acid C 6 H 4 (NO 2 )N (SO 3 H) 
 NH(SO 3 H). Its dipotassium salt consists of sulphur-yellow needles, 
 formed on adding an excess of a sulphite solution to nitro-diazo-benzol 
 ester, nitrate, or potassium iso-diazo-benzol. Hydrochloric acid 
 
DERIVATIVES OF PHENYL-HYDRAZIN 157 
 
 resolves it into p-nitro-phenyl-hydrazin, and it dissolves in an excess 
 of potash to a red tripotassium salt C 6 H 4 (NO 2 )N(SO 3 K)NK(SO 3 K) 
 (B. 29, 1830). 
 
 Azo- benzol- phenyl-hydrazin-sulphonic acid C 6 H 5 N : N.C 6 H 4 NH. 
 NHSO 3 H, in purple needles decomposing even below 100, is formed 
 by the action of SO 2 upon a concentrated solution of diazo-benzol 
 sulphate. With aldehydes it condenses to hydrazones, splitting off 
 the sulpho-group (C. 1909, I. 355). 
 
 Phenyi-benzol-sulphazide C 6 H 5 NH.NH.SO 2 C 6 H 5 , m.p. i48-i5o, 
 formed from phenyl-hydrazin and benzol sulpho-chloride in ether, and 
 from a diazo-benzo-salt solution with SO 2 or Na hydrosulphite (B. 20, 
 1238 ; 40, 422). 
 
 For the action of PC1 3 , POC1 3 , PSC1 3 , AsCl 3 , BC1 3 , SiCl 4 upon 
 phenyl-hydrazin, see A. 270, 123. 
 
 CARBOXYLIC ACID DERIVATIVES OF PHENYL-HYDRAZIN. Acid 
 residues of the most varied character can be as readily introduced into 
 phenyl-hydrazin, and generally by the same methods, as into aniline. 
 The domain of the bodies thus won from phenyl-hydrazin is scarcely 
 less extensive than that of the acid derivatives of aniline, and in the 
 multiplicity of phenomena really surpasses it. 
 
 The acid hydrazides and the hydrazido-acids have shown themselves 
 to be as well adapted as the phenyl-hydrazones for the formation 
 of heterocyclic derivatives. Each group of carboxylic derivatives of 
 phenyl-hydrazin will be followed by the most important hetero-ring 
 formations, arranged in tabular form, which will later be discussed 
 in a different connection in the section devoted to " heterocyclic 
 compounds." 
 
 The nitro-hydrazones, amidrazones, and formazyl derivatives will re- 
 ceive attention at the conclusion of the simpler carboxylic derivatives 
 of phenyl-hydrazin. 
 
 Fatty Acid Derivatives. The fatty acid residues enter the amido- 
 group of phenyl-hydrazin very readily with the production of sym. or 
 J3-acidyl compounds. The unsym. or a-acidyl compounds are made 
 (i) by the action of acid chlorides or anhydrides upon sodium phenyl- 
 hydrazin (B. 22, R. 664) ; (2) by action of suitable haloid derivatives 
 upon jS-acetyl-phenyl-hydrazin, and subsequent splitting off of the 
 j8-aceto-group on boiling with dilute sulphuric acid, when the group 
 occupying the a-position will not be attacked (B. 26, 945). 
 
 The sym. phenyl-hydrazides, treated with ferric chloride and con- 
 centrated sulphuric acid, yield reddish to bluish violet colours, whereas 
 the unsym. bodies are not coloured (B. 27, 2965, Billow's reaction). 
 
 Sym. formyl-phenyl-hydrazide C 6 H 5 NH.NH.CHO, from formic acid 
 and phenyl-hydrazin, melts at 145 (B. 27, 1522 ; 28, B. 764). 
 
 Unsym. or a-aeeto-phenyl-hydrazide C 6 N 5 N(COCH 3 )NH 2 , m.p. 
 124, is obtained from ajS-diaceto-phenyi-hydrazin, by heating with 
 dilute sulphuric acid (B. 27, 2964). Sym. or j8-aceto-phenyl-hydra- 
 zide C 6 H 5 NH.NHCOCH 3 , m.p. 128, from phenyl-hydrazin with acetic 
 anhydride, or by boiling with glacial acetic acid (A. 100, 129). aj8-Di- 
 aceto-phenyl-hydrazide C 6 H 5 N(CO.CH 3 )NHCOCH 3 , m.p. 106, from 
 potassium phenyl in ether with acetyl chloride (B. 20, 47). Propionyl- 
 iso-butyryl-phenyl-hydrazide, m.p. 158 and 143, see C. 1898, II. 1051. 
 Hetero-ring Formations of the Fatty Acid Phenyl-hydrazide Deri- 
 
158 ORGANIC CHEMISTRY 
 
 vatives. n-Phenyl-triazole results when formyl-phenyl-hydrazide is 
 heated with formamide (B. 27, R. 801). n-Diphenyl-iso-dihydro- 
 tetrazin is also a formic-acid derivative of phenyl-hydrazin. It re- 
 sults from the action of chloroform and caustic potash upon phenyl- 
 hydrazin (compare action of chloroform and caustic potash upon 
 primary amines : I. 236, and II. 84, isonitriles or carbylamines) . 
 
 The sym. or ^-acidyl-phenyl-hydrazides, treated ' with phosgene, 
 thio-phosgene, and iso-cyan-phenyl chloride, yield heterocyclic com- 
 pounds the oxybiazolin derivatives (B. 26, 2870), which can also be 
 regarded as derivatives of carbonic acid : 
 
 C 6 H 6 NH.NHCHO H : CONH ? _ > C fl H 6 N_N\ CH n . phenyl . triazole 
 
 HCCl, C 8 H 5 N - N=CH n-Diphenyl-iso-dihydro- 
 CH=N ttCH tetrazin 
 
 C 6 H 5 NH.NH.COCH 3 
 
 coci t C 8 H 6 N - N\ n-Phenyl-c-methyl- 
 
 CO O/ 3 oxybiazolone 
 CSC1 L __ > C 6 H 5 N - N\ n-Phenyl-c-methyl- 
 
 CO O/ ' 3 thio-oxybiazolin 
 C 6 H 5 N N\ n-Phenyl-c-methyl- 
 
 / ' 3 phenyl-imido-oxybiazolin. 
 
 ALCOHOLIC ACID DERIVATIVES OF PHENYL-HYDRAZIN. Sym. 
 Phenyl-hydrazido-aeetic acid C 6 H 5 NH.NH.CH 2 CO 2 H, m.p. 158, is 
 obtained by reduction of glyoxylic phenyl-hydrazone, a process which 
 can be reversed by oxidation with ammoniacal copper solution. Its 
 ester is formed, besides the unsym. compound, from chloro-acetic ester 
 and phenyl-hydrazin, whereas chloro-acetic acid, and its amides, 
 yield unsym. Phenyl-hydrazido-aeetic acid C 6 H 5 N(NH 2 )CH 2 COOH, 
 m.p. 167, or its derivatives (B. 36, 3877 ; cp. also the behaviour of 
 chloracetyl ureas and urethanes with phenyl-hydrazin (C. 1899, ^- 4 21 )- 
 
 The ester of the unsym. acid is formed by reduction of nitroso- 
 phenyl-glycin ester C 6 H 5 N(NO)CH 2 CO 2 C 2 H 5 (B. 28, 1223) ; amide, 
 m.p. 150; anilide, m.p. 149. Unsym. Phenyl-hydrazide C 6 H 5 N(NH 2 ) 
 CH 2 CON(NH 2 )C 6 H 5 , m.p. 155 (A. 301, 55) ; sym. Phenyl-hydrazide 
 C 6 H 5 N(NH 2 )CH 2 .CONHNHC 6 H 5 , m.p. 178 (B. 29, 622). 
 
 Unsym. Phenyl-hydrazido-^-propionic ester C 6 H 5 N(NH 2 ).CH 2 .CH 2 . 
 CO 2 C 2 H 5 , b.p. 175, from nitroso-j8-anilido-propionic ester (B. 29, 
 515). 
 
 Unsym. PhenyI-hydrazido--butyrie acid C 6 H5N(NH 2 ).CH(CH 3 ) 
 CH 2 COOH, m.p. in , from j8-chloro-butyric acid with phenyl-hydra- 
 zin (/. pr. Ch. 2, 45, 87). 
 
 Hetero-ring Formation of Phenyl-hydrazido-acids. (i) With form- 
 amide, unsym. phenyl-hydrazido-acetic ester condenses to phenyl- 
 keto-hydro-j8-triazin. 
 
 (2) Similarly, unsym. anilido-acetic-a-phenyl-hydrazide C 6 H 5 N 
 (NH 2 )CO.CH 2 NHC 6 H 5 , with cryst. formic acid, gives n-diphenyl-keto- 
 tetrahydro-a-triazin. 
 
 (3) The i-phenyl-semicarbazide-i-acetic ester C 6 H 5 NH(CH 2 COOR) 
 NHCONH 2 , obtained from unsym. phenyl-hydrazido-acetic ester with 
 potassium cyanate, on saponification, yields n-phenyl-diketo-hexahydro- 
 a-triazin. 
 
 The phenyl-hydrazido-carboxylic acids 4, 5, and 6 (below), corre- 
 
DERIVATIVES OF PHENYL-HYDRAZIN 159 
 
 spending to the j8-oxy-acids, so easily develop anhydrides (pyrazoli- 
 dones and lactames) that they frequently escape isolation. 
 
 C 6 H 5 N.NH 2 HCONH, C 6 H 6 N - N=CH n-Phenyl-keto-tetra- 
 
 CH 2 COOC 2 H 5 ~~ CH 2 CO - &H hydro-a-triazin 
 
 C 6 H 5 N.NH 2 HCOOH C 6 H 5 .N - N = CH n-Diphenyl-keto- 
 
 5 CO.CH 2 .NHC,H 5 - CO- CH 2 _*C 8 H 5 *^ 
 
 C 6 H 5 NH-NH-CO _ ^C fl H 5 NH NH CO n-Phenyl-diketo- 
 CH 2 .CO 2 RtfH 2 " CH 2 CO ftH hexahydro-a-triazin 
 
 4. C 6 H 5 NHNH 2+ C1CH 2 CH 2 C0 2 H_C 6 H 6 .N-_NH >CO 
 
 5. C 6 H 5 NH.NH 2 +CH 3 CH : 
 . 
 
 C 6 H 5 N - NH 2 C 6 H 6 N - NH 2 \ i-Phenyl- 5 -methyl- 
 
 CH 3 CH CH 2 CO a H CH 3 CH CH 3 -pyrazolidone. 
 
 PHENYL-HYDRAZIN DERIVATIVES OF THE MONO-KETONIC ACIDS. 
 The a-, {3-, and y-ketone carboxylic esters react with phenyl-hydrazin, 
 forming phenyl-hydrazones, just as the ketones do. The phenyl-hydra- 
 zones of a- and y-ketone carboxylic acids are known. Zinc chloride 
 or concentrated sulphuric acid rearranges the phenyl-hydrazones of the 
 a-, ft-, and y-ketone carboxylic acids into indol derivatives (compare 
 indol formation of the ketone phenyl-hydrazones). The phenyl-hydra- 
 zones of the ft- and y-ketone carboxylic esters and of the free y-ketone 
 carboxylic esters manifest great tendency to the lactazame formation. 
 Laevulinic phenyl-hydrazone (i) yields i-phenyl-3-methyl-pyridazinone 
 (q.v.), and under other conditions a-methyl-indol- ft- acetic acid. Ace to- 
 acetic ester phenyl-hydrazone C 6 H 5 NH.N=C(CH 3 ).CH 2 .CO 2 C 2 H 5 , melt- 
 ing at 50, is formed on adding aceto-acetic ester to phenyl-hydrazin 
 (B. 27, R. 793), and spontaneously forms i-phenyl-^-methyl-pyrazolone 
 (q.v.) ; whereas with acetyl chloride or excessive hydrochloric acid it 
 yields i-phenyl-^-methyl-^-ethoxy-pyrazole. 
 
 HETERO-RING FORMATIONS OF THE PHENYL-HYDRAZONE 
 KETONE ACIDS. 
 
 i. Indol condensation : p. 155 
 _= IC 6 H 5 _ 3 _ \ 
 
 CH 2 -CH 2 -COOH COOH.CH 2 .C- acetic acid 
 
 = -NHC 6 H 5 CH 3 C-NH X a -Methyl-indol- 
 
 2. Lactazame : 
 
 C 6 H 5 .NH N _ C 6 H 5 N - N i-Phenyl-3-methyl- 
 
 C0 2 C 2 H 5 CH 2 .C.CH 3 CO.CH 2 .C.CH 3 5 -pyrazolone 
 
 C 6 H 5 .NH N _ > C 6 H 5 N - N i-Phenyl-3-methyl- 
 
 CO 2 H.CH 2 .CH 2 .C.CH 3 CO.CH 2 .CH 2 C.CH 3 pyridazinone 
 
 3. Pyrazole : 
 
 C 6 H 5 .NH N _ C 6 H 5 N - N i-Phenyl-3-methyl- 
 
 C 2 H 5 OCO.CH 2 .C.CH 3 * C 2 H 5 OC=CH.C.CH 3 ethoxy-pyrazole. 
 
 PHENYL-HYDRAZIN DERIVATIVES OF CARBONIC ACID. On saturat- 
 ing an aqueous solution of phenyl-hydrazin with CO 2 we obtain Phenyl- 
 hydrazin-phenyl-carbazinate C 6 H 5 NHNHCOONH 3 NHC 6 H 5 , a white 
 
160 ORGANIC CHEMISTRY 
 
 crystalline mass (A. 190, 123 ; C. 1901, II. 1051). Phenyl-earbazinie 
 ethyl ester C 6 H 5 NHNHCOOC 2 H 5 , m.p. 86, is formed when C1.CO 2 C 2 H 5 
 acts upon an etheric solution of phenyl-hydrazin. Heated to 240 it 
 splits off alcohol, and passes into Diphenyl-urazin (A. 263, 278 ; B. 26, 
 R. 20). Unsym. Phenyl-hydrazido-formie ester C 6 H 5 N(NH 2 )COOC 2 H 5 , 
 an oil, is formed from its aceto-compound obtained from aceto-phenyl- 
 hydrazin, and chloro-formic ester (B. 29, 829; 32, 10). On further 
 treatment with chloro-formic ester it gives Phenyl-hydrazido-a,j8-di- 
 carboxylic ester C 6 H 5 N(CO 2 C 2 H 5 )NH.CO 2 C 2 H 5 , m.p. 59, with COC1 2 ; 
 Diphenyl-carbazide-dicarboxylie ester CO[NH.N(C 6 H 6 )CO 2 C 2 H 6 ] 2 , m.p. 
 159. a- and j3-Cyano-phenyl-hydrazin C 6 H 5 (CN)N.NH 2 , two unstable 
 oils, formed together by the action of cyanogen bromide upon phenyl- 
 hydrazin (C. 1907, II. 802). On saponification, the a-compound yields 
 a-Phenyl-semicarbazide, carbaminic a-phenyl-hydrazide NH 2 .N(C 6 H 5 ). 
 CO.NH 2 , m.p. 120. 
 
 j8-Phenyl-semicarbazide, carbaminic f$-phenyl-hydrazide C 6 H 5 NHNH 
 CONH 2 , m.p. 172, from phenyl-hydrazin salts, and potassium 
 cyanate (A. 190, 113), or by heating phenyl-hydrazin with urea or 
 urethane. On heating, it passes into phenyl-urazol, and diphenyl- 
 urazin, with formation of CO, CO 2 , NH 3 , and benzene (B. 21, 1224). 
 With potassium hypochlorite it forms diazo-benzolimide (B. 40, 3033). 
 Phenyl-semicarbazide changes into oxy-biazolone compounds with 
 COC1 2 , CSC1 2 , and C 6 H 5 NCC1 2 (B. 26, 2870), like sym. aceto-phenyl- 
 hydrazin. For homologous aryl semicarbazides, see C. 1898, II. 199. 
 
 m-Tolyl-semicarbazide CH 3 C 6 H 4 NH.NH.CONH 2 , m.p. 184, from 
 m-tolyl-hydrazin and urea. It possesses antipyretic properties (C. 
 1905, I. 196 ; II. 1299). 
 
 2, 4-Diphenyl-semicarbazide, phenyl-carbaminic a-phenyl-hydrazide 
 C ? H5NH.CO.N(C 6 H 5 )NH 2 , m.p. 165, is best obtained from phenyl- 
 dithio-carbazinic ester C 6 H 5 NHNHCSSCH 3 , by combining it with 
 phenyl cyanate to C 6 H 5 NHCON(C 6 H 5 ).NHCSSCH 3 , converting the 
 latter, with methyl iodide and alkali, into the dimethyl ester C 6 H 5 
 NHCON(C 6 H 5 )N :C(SCH 3 ) 2 and then breaking up with dilute sul- 
 phuric acid. The 2, 4-diphenyl-semicarbazide is heated above its m.p. 
 and converted into the isomeric 1, 4-Diphenyl-semicarbazide, phenyl- 
 carbaminic fi-phenyl-hydrazide C 6 H 5 NH.CO.NHNHC 6 Hg, m.p. 176, 
 which is distinguished from its isomers by its reaction with FeCl 3 , and 
 the resulting formation of an azo-body (B. 36, 1362). Triphenyl-semi- 
 carbazide (C 6 H 5 ) 2 NCO.N(C 6 H 5 )NH 2 , m.p. 128, formed as an aceto- 
 compound, from diphenyl-urea chloride and j3-aceto-phenyl-hydrazin 
 (B. 33, 246). 
 
 Diphenyl-carbazide, phenyl-hydrazin-urea (C 6 H 5 NH.NH) 2 CO, m.p. 
 170, obtained by heating urethane or phenyl carbonate with phenyl- 
 hydrazin (B. 20, 3372 ; C. 1900, 1. 290) ; by boiling with alcoholic potash, 
 or bv the action of copper or mercury salts, it loses two H atoms and is 
 transformed into salts of Diphenyl-earbazone C 6 H 5 N : NCONHNHC 6 H 5 , 
 orange-red needles of m.p. 157 with decomposition (A. 263, 274). 
 With metals this diphenyl-carbazone forms red or blue and partly 
 explosive salts of the type C 6 H 5 N 2 CONMeNHC 6 H 5 , and it dyes silk or 
 wool in a neutral bath.. Like the diphenyl-carbazide, it is converted 
 by oxidation, with silver and acetate, into diphenyl-carbo-diazone 
 (C 6 H 6 N : N) 2 CO, colourless needles, decomposing on heating, and re- 
 
PHENYL-HYDRAZIN DERIVATIVES 161 
 
 generating the K salt 'of diphenyl-carbazone on boiling with alcoholic 
 potash (C. 1900, II. n'o8 ; 1901, I. 703 ; II. 682). 
 
 Cyclic Urea and Carbamic Acid Derivatives. Phenyl-urazol is pro- 
 duced on heating phenyl-semicarbazide, or phenyl-hydrazin chloro- 
 hydrate with urea, or biuret with phenyl-hydrazin. Diphenyl-urazin 
 results upon heating ethyl-phenyl-carbazinate and phenyl-semicarbazide 
 (A. 263, 582). 
 
 i-Phenyl-3-methyl-5-triazolone is obtained from acetyl-ur ethane and 
 phenyl-hydrazin (B. 22, R. 737) : 
 
 C 6 H 5 NH.NH 2 +2NH 2 CONH 2 -- C H5N ~"S^NH Phenyl-urazol 
 
 2 C 6 H 5 NH.NHCOOC 2 H 5 - -> C 6 H 5 N --- NH-CO Diphenyl . urazin 
 
 2C 6 H 5 NH.NHCONH 2 - - > CO NH NC 6 H 5 
 
 C 6 H 5 NH.NH 2 +NH 2 5 -_> 6 5 \ NR i-Phenyl- 3 -methyl- 
 
 - H 3 \CH 5-triazolone. 
 
 PHENYL-HYDRAZIN DERIVATIVES OF CARBONIC ACID. On passing 
 CS 2 through an etheric solution of phenyl-hydrazin we obtain Phenyl- 
 dithio-carbazimie phenyl-hydrazin C 6 H 5 NH.NH.CSSNH 3 NHC 6 H 5 , m.p. 
 96 . From solutions of th e salts of phenyl-dithio-earbazimie acid, mineral 
 acids precipitate the free acid in fine shiny flakes, easily oxidised to the 
 corresponding bisulphide (A. 190, 114). The mono- and dialkyl esters 
 obtained from the acid with alkali and halogen alkyls are partly 
 derivable [from the desmotropic form of phenyl-sulpho-carbazinic acid 
 C 6 H 5 NHN : C(SH) 2 , corresponding to the formula 
 
 C 6 H 5 NHN : C(SCH 3 )SH, C 6 H 3 NHN : C(SCH 3 ) 2 , C 6 H 5 NHN : 
 On introducing two different radicles, the resulting compounds 
 
 <"OTQ 
 \ occur in stereo-isomeric forms. Dilute acids break 
 oK. 
 
 up the dialkyl esters of phenyl-dithio-carbazinic acid into phenyl- 
 hydrazin and dithio-carbonic ester (see Vol. I. and B. 34, 1119 ; /. pr. 
 Ch. 2, 65, 473). On treating the potassium salt of phenyl-sulpho- 
 carbonic acid with COC1 2 or CS 2 we obtain n-phenyl-thio-biazolone- 
 sulphohydrate and also the dithio-sulphohydrate. 
 
 a-Phenyl-sulpho-semicarbazide, thio-carbaminic a-phenyl-hydrazide 
 NH 2 .N(C 6 H 5 )CS.NH 2 , m.p. 153, from the action of NH 4 SH upon 
 a-cyano-phenyl-hydrazin. 
 
 jg-Phenyl-sulpho-semicarbazide C 6 H 5 NH.NH.CSNH 2 , m.p. 200, 
 isomeric with phenyl-thio-semicarbazide, is obtained from phenyl- 
 hydrazin sulphocyanate at i6o-i70 ; on heating with HC1 it 
 passes into sulpho-earbizin and benzo-diazo-thin (B. 27, 861). 
 
 2, 4 - Diphenyl - sulpho - semicarbazide, phenyl - thio - carbaminic a- 
 phenyl-hydrazide C 6 H 5 NHCSN(C6H 5 )NH 2 , m.p. 139, is obtained from 
 phenyl-dithio-carbaminic acid with aniline, as well as the combination 
 of phenyl-mustard oil with phenyl-hydrazin. It is transposed like the 
 2, 4-diphenyl-semicarbazide, but much more easily, into 2, 4-Di- 
 phenyl-sulpho-semiearbazide, or phenyl - thio - carbaminic p-phenyl- 
 hydrazide C 6 H 5 NHCSNHNHC 6 H 5 , m.p. 176. Both isomeric com- 
 pounds give, with methyl iodide and alkali, the isomeric methyl 
 ethers C 6 H 5 N : C(SCH 3 )N(C 6 H 5 )NH 2 and C 6 H 5 N.C(SCH 3 ).NHNHC 6 H 5 . 
 
 VOL. II. M 
 
162 ORGANIC CHEMISTRY 
 
 With benzaldehyde, the 2,4- diphenyl - thio - semicarbazide reacts 
 smoothly with formation of a benzylidene derivative, while the 
 i, 4-compound does not react in this manner. For other isomeric 
 transpositions, see B. 34, 320. 
 
 Diphenyl-sulpho-earbazide (C 6 H 5 NH.NH) 2 CS, m.p. 150, is formed 
 by heating phenyl-hydrazin-phenyl-sulpho-carbazinate to ioo-iio. 
 
 Diphenyl - sulpho-carbazone C 6 H 5 N = N.CSNH.NHC 6 H 5 , bluish- 
 black crystals formed by short boiling of diphenyl-sulpho-carbazide 
 with moderately concentrated alcoholic potash. 
 
 Diphenyl-sulpho-earbo-diazone (C 6 H 5 N=N) 2 CS, from diphenyl- 
 sulpho-carbazone by oxidation with manganese peroxide hydrate, 
 forms small red needles (A. 212, 316). 
 
 HETERORING FORMATION OF PHENYL-HYDRAZIN DI-THIO- 
 CARBONIC ACID DERIVATIVES. 
 
 COCl. C 6 H 5 N N\p CTJ n-Phenyl-thio-biazolon- 
 
 CHNHNHCSSK / > CO-S/* sulphohydrate 
 
 C 6 H 5 JNH.JNi.C. c ^ c 6 H 5 N N\ r <m n-Phenyl-dithio-biazolin- 
 
 CS S/ sulphohydrate 
 
 C e H 6 NH.NH.CSNH 2 ~ NH '- C.H 4 /* Phenyl.-sulpho-carbizin 
 
 4 \g H Benzo-diazo-thin. 
 
 PHENYL-HYDRAZIN DERIVATIVES OF GUANIDIN. Anilino-guanidin 
 NH : C(NH 2 ).NHNHC 6 H 5 , and Amido-phenyl-guanidin NH : C(NH 2 ). 
 N(C 6 H5JNH 2 , are produced together from cyanamide and phenyl- 
 hydrazin (B. 29, R. 1109 ; cp. /. pr. Ch. 2, 61, 440 ; C. 1901, II. 591) ; 
 under different conditions a phenyl-hydrazin derivative of biguanide 
 is formed, the unstable Anilo-biguanide C 6 H 5 NH.NH.C : (NH).NH.C : 
 (NH)NH 2 . On heating with cyanamide the anilo-biguanide (I.) passes 
 into n-phenyl-guanazol (II.), which is also formed from diazano- 
 diamide (III.) with phenyl-hydrazin (B. 24, R. 649) : 
 
 I. C 6 H 6 NH.NH.C:NH II. C 6 H 5 N.NH.C : NH III. C 6 H 5 NH.NH 2 +CN 
 NH.\C NH HN:C NH >C ^ 
 
 DianUino-guanidin NH : C(NH.NHC 6 H ? ) 2 , bromo-hydrate, m.p. 
 180, is formed as a by-product in the action of BrCN upon phenyl- 
 hydrazin. 
 
 PHENYL-HYDRAZIN DERIVATIVES OF DICARBOXYLIC ACIDS. 
 Corresponding to oxanilic acid and oxanilide we have Oxal-phenyl- 
 hydrazilie acid C 6 H 5 NH.NH.CO.CO 2 H, m.p. 110 (A. 236, 197), and 
 Oxal-phenyl-hydrazide (C 6 H 5 NH.NH.CO) 2 , m.p. 278. 
 
 From malonic acid we have the following phenyl-hydrazin deriva- 
 tives : Malonic ester phenyl-hydrazide, malono-phenyl-hydrazilic ester 
 C6H 5 .NH.NH.CO.CH 2 .COOC 2 H 5 , m.p. 90, from malonic ester chloride 
 with phenyl-hydrazin. The compound easily dissolves in KHO, and, 
 from the solution, HC1 precipitates Malonyl-phenyl-hydrazide, or 
 i-phenyl-3, ^-pyrazolidone. Malonyl - diphenyl - hydrazide (C 6 H 5 NH. 
 NH.CO) 2 CH 2 , m.p. 187, from malonic acid amide and phenyl-hydrazin 
 at 200 (B. 25, 1550). 
 
 Compounds of ethylene-succinic acid are known corresponding to 
 
PHENYL-HYDRAZIN DERIVATIVES 163 
 
 those of malonic acid : Succinic phenyl-hydrazilic ester, m.p. 107 ; 
 Sueeinyl-phenyl-hydrazin (see below), from phenyl-hydrazin chloro- 
 hydrate and succinyl chloride (B. 26, 2181) ; Succinyl-diphenyl- 
 hydrazide, m.p. 209 (B. 21, 2462), and also Anilo - succimide, 
 (CH 2 CO) 2 NNHC 6 H 5 . 
 
 PHENYL-HYDRAZIN DERIVATIVES OF OLEFIN- AND OXY-DICAR- 
 BOXYLIC ACIDS. Maleinic anhydride yields, with phenyl-hydrazin, 
 Maleino-phenyl-hydrazil. On boiling maleiinic or fumaric acid in 
 water with excess of phenyl-hydrazin, it adds itself as it does to 
 acrylic or crotonic acid, and lactazame is formed subsequently (B. 
 26, 117). l-Phenyl-5-pyrazolidone-3-carboxylie acid is formed. 
 
 HETERO-RING FORMATION OF PHENYL-HYDRAZIN DERIVATIVES 
 OF DlCARBOXYLIC ACIDS. 
 
 CONH.NHC 6 H 5 CH /CO NH Malonyl-phenyl-hydrazin, 
 
 CO ttC 6 H 5 i -Phenyl-3, 5 -pyrazolidone 
 
 CH COOH NH,NHC t H t CO 2 H.CHNH\ NC H i-Phenyl-5-pyrazolidone- 
 CH COOH " CH 2 CO/ 3-carboxylic acid. 
 
 16. Hydrazidins or Amidrazones. Nitrazones. Phenyl-hydrazo-aldoximes. 
 Phenyl-azo-aldoximes (Nitrosazones). Formazyl Compounds. 
 
 In connection with the phenyl-hydrazin derivatives of the carboxylic 
 acids, some classes of compounds must be dealt with which are com- 
 posed according to the amidine type. The hydrazidins are amidins 
 in which the imido-group is replaced by the phenyl-hydrazone group. 
 In the nitrazones there is also a replacement of the amido-group by 
 the nitro-group, and, in the formazyl compounds, by the azo-phenyl 
 group: 
 
 /NH 2 
 
 3H3C \N^HC 6 H 5 
 
 Ethenyl-phenyl- 
 hydrazidin 
 
 3 \NNHC 6 H 5 
 Nitro-acetaldehy- 
 drazone 
 
 HC /N=NC 6 H 5 
 \N NHC 6 H 5 
 Fonnazyl 
 hydride. 
 
 Acetamidin 
 
 To these must be added the phenyl-azo-aldoximes, the stable trans- 
 position products of the very unstable nitroso-phenyl-hydrazones : 
 
 rM r /NO r rr r/ /NOH 
 
 ' HsC \NNHC 6 H 5 HaC \N : NC 6 H 5 
 
 Nitroso-aceto-phenyl-hydrazone Phenyl-azo-acetaldoxime. 
 
 HYDRAZIDINS OR AMIDRAZONES. Ethenyl - phenyl - hydrazin 
 
 CH 3 C^ KNHC6H5 . The chlorohydrate of this base is formed by the 
 \NH 2 
 
 action of phenyl-hydrazin upon hydrochloric acetimido-ether (B. 17, 
 2002) . Cyan-amidrazone or dieyano-phenyl-hydrazinNC c^^ HC H 5 1 
 m.p. 160, with decomposition, and diamidrazone or cyano-phenyl- 
 
164 ORGANIC CHEMISTRY 
 
 hvdrazin f C ^" N 5"?\P^ , m.p. 225, are formed by the action of 
 y V NH 2 / /' 
 
 cyanogen upon phenyl-hydrazin. Dicyano-phenyl-hydrazin is also 
 formed by reduction of the prussic acid addition product of diazo-benzol 
 cyanide, to which, therefore, probably the following formula must be 
 
 ascribed : C C H 5 N : NC^ H (B. 28, 2082 ; A. 287, 300). The constitution 
 of cyan-amidrazone follows from its formation by the action of phenyl- 
 hydrazin upon Flaveanic hydride NC C \^ H > and tne constitution of 
 diamidrazone from its formation by the action of phenyl-hydrazin 
 upon Rubeanie hydride NH S / C - C \N H ' see VoL L ) and upon Oxal " 
 
 diamido-oxime ^H^/C c/* H (B. 26, 2385). Diamidrazone is also 
 
 jSfHjj/ r^ 2 
 
 formed by the reduction splitting of diformazyl. 
 
 Acetyl-amidrazone, pyro-racemic acid phenyl - hydrazidine 
 
 CH 3 CO.C<f N>NHCeH5 , melting at 182, is produced by reducing formazyl 
 \NH 2 
 
 methyl-ketone with ammonium sulphide (B. 26, 2783). 
 
 HETERO-RING FORMATIONS WITH THE AMIDRAZONES. The ami- 
 drazones condense with carboxylic acids, their anhydrides or chlorides, 
 to heterocyclic derivatives of the triazol group (q.v.). Nitrous acid 
 converts the amidrazones into tetrazol derivatives (q.v.). Cyan-ami- 
 drazone is changed by acetic anhydride to n-phenyl-3-cyano-5-methyl- 
 triazol ; by nitrous acid to n-phenyl-3-cyan-tetrazol : 
 
 C 6 H 5 NH.N\ r rM CH 3 COQH C 6 H 5 N N\ r rM n-Phenyl-3-cyan- 
 NH 2 / CH 3 C=N/ 5-methyl-triazol 
 
 C 6 H S NH.N\ C CN N 2 3 C 6 H 5 N N\ CCN n-Phenyl-3-cyan- 
 NH 2 / S=N/ tetrazol. 
 
 NITRO - HYDRAZONES or NiTRAZONES are the nitro - compounds 
 coi responding to the amidrazones ; they are formed from the alkali 
 salts of primary nitro-paraffins (Vol. I.) with diazonium salts, and 
 were formerly regarded as nitro-azo-paraffins ; but the free compounds 
 must probably be regarded as nitrogenated hydrazones, while their 
 metallic salts are derivable from the tautomeric form of Phenyl-azo- 
 
 nitro-aeid RC \NNC H ' They are easily split up by alkalies into 
 nitrites, and jS-Acidyl-phenyl-hydrazides (B. 31, 2626) : 
 
 CH 3 C(NO 2 ) : NNHC 6 H 5 +KOH = CH 3 CONHNHC 6 H 5 +NO 2 K. 
 
 Certain poly-halogenated diazo-compounds also unite with primary 
 nitro-paramns in the molecular ratio 2:1, mixed azo-compounds 
 being obtained (B. 36, 3833)- 
 
 Nitro-formaldehydrazone CH(NO 2 ) : N.NHC 6 H 5 , occurs in two 
 forms : a-form, m.p. 75 ; j8-form, m.p. 85 (B. 34, 2002). With 
 diazo-methane it yields an unstable O-methyl ether HC(: NOOCH 3 )N : 
 NC 6 H 5 , m.p. 54, but with methyl iodide, and sodium methylate, it 
 gives an N-methyl derivative HC(NO 2 ) : NN(CH 3 )C 6 H 5 , m.p. 92, 
 which, on reduction, yields Phenyl-methyl-formhydrazin CH(NH 2 ) : 
 NN(CH 3 )C 6 H 5 , m.p. 101, and then methyl-amine and unsym. phenyl- 
 methyl-hydrazin (B. 34f, 574). 
 
PHENYL-HYDRAZO-ALDOXIMES 165 
 
 Nitro-acetaldehydrazone CH 3 C(NO 2 ) : NNHC 6 H 5 , yellow flakes, m.p. 
 142, gives, with diazo-methane, O-methyl ether CH 3 C(: NOOCH 3 ). 
 N : NC 6 H 5 , m.p. 68. 
 
 PHENYL - HYDRAZO - ALDOXIMES AND PHENYL - AZO - ALDOXIMES 
 (NITROSAZONES). Formation : (i) On reducing nitrazones with Am 2 S 
 we obtain phenyl-hydrazo-aldoximes, which are easily oxidised, by 
 ferric chloride, to phenyl-azo-aldoximes : 
 
 RC(NO 2 ) : NNHC 6 H 5 H > RC( : NOH)NHNHC 6 H 5 _> RC( : NOH)N : NC 6 H 5 . 
 
 (2) The O-methyl ethers of the nitrazones, boiled in water, easily decom- 
 pose into formaldehyde and phenyl-azo-aldoximes : 
 
 (3) Aldehyde-phenyl-hydrazones, treated with amyl nitrite and 
 sodium alcoholate, or pyridin, probably first give the very unstable 
 nitroso-hydrazones (nitrosazones), which easily transpose into azo- 
 aldoximes (B. 35, 54, 108 ; 36, 53, 86, 347) : 
 
 RCH : NNHC 6 H 5 > RC(NO) : NNHC 6 H 5 > RC( : NOH)N : NC 6 H 5 . 
 
 The aryl hydrazones of glyoxylic acid, treated with HNO 2 , split 
 off CO 2 and pass into phenyl-azo-aldoximes (C. 1905, I. 1538). 
 
 Phenyl - hydrazo - formaldoxime HC(: NOH)NH.NHC 6 H 5 , white 
 needles, m.p. 113, from nitro-formaldehydrazone, with alcoholic 
 Am 2 S, gives, by oxidation with ferric chloride, Phenyl-azo-formal- 
 doxime, golden-yellow needles, m.p. 94 with decomposition. 
 
 Phenyl-hydrazo-acetaldoxime CH 3 C(: NOH)NHNHC 6 H 5 , m.p. 128, 
 from nitro-acetaldehydrazone, gives by oxidation Phenyl-azo- 
 acetaldoxime CH 3 C(:NOH)N :NC 6 H 5 , m.p. 118. This is obtained 
 from the O-methyl ether of nitro-acetaldehydrazone on boiling with 
 water, also from acetaldehyde-phenyl-hydrazone, or benzol-azo-ethane 
 with amyl nitrite and sodium ethylate, or pyridin, and also from 
 acetaldehyde-ammonia with nitroso-phenyl-hydrazin (B. 35, 1009). 
 Its Ag salt, with methyl iodide, gives the O-methyl ether CH 3 C 
 (: NOCH 3 )N : NC 6 H 5 , an oil of b.p. 12 134 ; whereas the Na salt 
 gives, with methyl iodide, an N-methyl ether, m.p. 96. This latter, 
 under the influence of sodium alcoholate, easily undergoes cyclic 
 condensations into Phenyl-methyl-triazol : 
 
 H 2 O 
 
 : NC 6 H 5 ' 
 
 HC1 converts the phenyl-azo-aldoximes, with primary addition, 
 and wandering of the chlorine atom into the benzene nucleus, into 
 Chloro-phenyl-hydrazo-aldoximes : 
 
 T-TC1 
 
 RC(: NOH)N : NC H 5 - - RC(: NOH)NH.NC1.C 6 H 5 > RC(: NOH)NH.NHG 6 H 4 C1. 
 
 FORMAZYL COMPOUNDS are strongly coloured, usually red, easily 
 crystallised substances. Their sulpho-acids are dyes (B. 33, 747). 
 They are obtained (i) from phenyl-hydrazones and normal diazo-benzol, 
 usually in alkaline solution ; (2) from phenyl-hydrazin and phenyl- 
 hydrazides ; the hydrazone-hydrazide produced at first oxidises, under 
 the influence of phenyl-hydrazin, with the loss of two hydrogen atoms ; 
 
166 ORGANIC CHEMISTRY 
 
 (3) from the phenyl-hydrazone chlorides, corresponding to the imide 
 chlorides, by action of phenyl-hydrazin (B. 27, 320 ; 29, 1386). 
 
 Formazyl hydride H ^^^. m ' p ' Il6 ( L 233 '' has been 
 obtained from formazyl-carboxylic acid by fusion, or by the action 
 of diazo-benzol acetate upon malonic acid, or from acetyl-formazyl 
 hydride CH(N 2 C 6 H 5 ) : NN(COCH 3 )C 6 H 5 , generated on acetyling form- 
 azyl-carboxylic acid with methylated potash (/. pr. Ch. 2, 65, 131). 
 
 Methyl-formazyl CH 3 C(N 2 C 6 H 5 ) : NNHC 6 H 5 , m.p. 121, see /. pr. 
 Ch. 2, 64, 213 ; B. 36, 87. 
 
 Formazyl-methyl ketone CB - CO - C \N N^H ' m ' p ' I34 ' results 
 from the action of diazo-benzol upon acetone, aceto-acetic ester, pyro- 
 racemic aldehyde hydrazone, and benzol-azo-acetyl acetone (B. 
 25, 3211). 
 
 Formazyl-carboxylic acid CO 2 H.C/^ -**' 1 ** TT , m.p. 162 with de- 
 
 NxN.JNri.C 6 H 5 
 
 composition, is made by saponifying the ethyl-f ormazyl-carboxylic ester, 
 m.p. 117. The latter is produced when diazo-benzol chloride acts 
 upon aceto-acetic ester, oxalo-acetic ester (B. 25, 3456), or upon phenyl- 
 
 hydrazone-mesoxalic-ester acid. Diformazyl c ^ .^^N.NHW 
 greenish-brown, brilliant flakes, m.p. 226. It results from the action 
 of diazo-benzol chloride upon laevulinic acid, hydro-chelidonic acid, or 
 acetone-diacetic acid, and from dioxy-tartrosazone. 
 
 Formazyl-acrylic acid co 2 H.CH : CH.C/^ ; ^3?* , m.p. 129 with 
 
 v-JN ! ^1 JtdLC-'girj.e 
 
 decomposition, formed by the action of diazo-benzol acetate upon 
 glutaconic acid (B. 40, 4927). 
 
 Formazyl-azo-benzol, Phenyl-azo-f ormazyl (C 6 H 5 N = N) 2 C = N . 
 NHC 6 H 5 , m.p. 162, from formazyl-carboxylic acid, glyoxalic phenyl 
 hydrazone or acetaldehyde, with diazo-benzol in alkaline solution 
 (/. pr. Ch. 2, 64, 199). In the action of diazo-benzol alkali upon pyro- 
 racemic acid, the first product is Formazyl-glyoxalic acid, m.p. 166, 
 which, on further action, is decomposed into oxalic acid and phenyl- 
 azo-f ormazyl (/. pr. Ch. 2, 64, 204). 
 
 Nitro-formazyl NO 2 .C(N 2 C 6 H 5 ) : NNHC 6 H 5 , m.p. 153, from sodium 
 nitro-methane, with diazo-benzol nitrate, is both a formazyl and a 
 nitrazone compound (B. 27, 156 ; cp. B. 33, 2043). 
 
 Hetero-ring Formations in Formazyl Compounds. Under the in- 
 fluence of strong mineral acids the formazyl compounds split off 
 aniline and give pheno-triazin derivatives : formazyl-carboxylic ester 
 gives a-pheno-triazin. On oxidation, the formazyl compounds give 
 tetrazolium compounds ; thus, from formazyl hydride n-Diphenyl- 
 tetrazolium hydroxide is obtained : 
 
 C 6 H 5 N=N\ CH O C 6 H 5 N(OH) : N\ rTT n-Diphenyl-tetrazolium- 
 
 C 6 H 5 NH N/ > C 6 H 5 tt N/" hydroxide. 
 
 Phenyl - nitroso - hydrazin C 6 H 5 N or C 6 H 5 NHNHNO, yellowish- 
 
 \NH 2 
 brown crystalline flakes easily passing into diazo-benzol-imide (A. 190, 
 
TETRAZONES 167 
 
 89). Obtained from phenyl-hydrazin and HNO 2 ; an excess of acid 
 oxidises phenyl-hydrazin to diazo-benzol nitrate (C. 1897, I- 3& 1 B. 33, 
 1718). Heating in indifferent solvents decomposes the phenyl-nitroso- 
 hydrazin with nitrous oxide and aniline (B. 41, 2809). By reduction 
 it is split up with recovery of phenyl-hydrazin. A similar behaviour 
 is shown by the nitroso-derivatives of alkylated phenyl-hydrazins. 
 
 Nitroso - a, - diethyl - phenyl - hydrazin C 6 H 5 N(C 2 H 5 )N(C 2 H 5 )NO 
 yields ethyl-aniline and ethyl-hydrazin (B. 36, 202). But in the re- 
 duction of Nitroso-formyl-phenyl-hydrazin C 6 H 5 N(NO)NHCHO, m.p. 
 85, and Nitroso-acetyl-phenyl-hydrazin C 6 H 5 N(NO)NHCOCH 3 , m.p. 
 63 with decomposition, with Na amalgam and alcohol, derivatives 
 of an hypothetical phenyl-triazane C 6 H5N(NH 2 ) 2 are obtained, and 
 these have been isolated in the form of their benzylidene compounds. 
 
 Benzylidene-formyl-phenyl-triazane C 6 H 5 N(N : CHC 6 H 5 )NHCHO, 
 m.p. 183, and Benzylidene-acetyl-phenyl-triazane C 6 H 5 N(N : CHC 6 H 5 ) 
 NHCOCH 3 , m.p. 163 (B. 35, 1900). Nitroso-phenyl-semicarbazide 
 C 6 H 5 N(NO)NHCONH 2 , m.p. 127 with decomposition, from phenyl- 
 semicarbazide \vith NO 2 Na and acetic acid, decomposes gradually even 
 at ordinary temperatures, and more rapidly on heating, with formation 
 of phenyl-azo-carbamide ; boiling with potassium hydroxide yields 
 diazo-benzol-imide (B. 28, 1925). 
 
 Tetrazones, or tetrazenes, derived from the hypothetical nitro- 
 gen hydride NH 2 N=N NH 2 , are formed from the unsym. alkyl- 
 phenyl- or diphenyl-hydrazins by oxidation with HgO in alcoholic or 
 etheric solution, or with dilute ferric chloride solution : 
 
 2C 6 H 5 N(CH 3 ).NH 2 +2O-C 6 H 5 .N(CH 3 ).N : N.N(CH 3 ).C 6 H 5 +2H 2 O. 
 
 They are solid bodies, decomposed on melting or boiling with dilute 
 acids. Dimethyl-diphenyl-tetrazone C 6 H 5 .N(CH 3 )N 2 .N(CH 3 )C 6 H 5 , m.p. 
 133. Diethyl-diphenyl-tetrazone, m.p. 108 (A. 252, 281). Tetra- 
 phenyl-tetrazone (C 6 H 5 ) 2 N.N 2 .N(C 6 H 5 ) 2 , m.p. 123, from as-Diphenyl- 
 hydrazin. p - Tetratolyl - tetrazone (CH 3 C 6 H 4 ) 2 N.N 2 .N(C 6 H 4 CH 3 ) 2 , 
 fiery-yellow needles, m.p. 134 with decomposition, from unsym. 
 p-ditolyl-hydrazin with MnO 4 K in acetone solution. On heating in 
 indifferent solvents the quaternary tetrazones decompose into nitrogen 
 and tetra-aryl- hydrazin. In concentrated acids they dissolve with 
 liberation of N, forming intensely blue solutions, the transformation 
 products being the same as those obtained with the corresponding tetra- 
 aryl-hydrazins (B. 41, 3502). 
 
 Hydro-tetrazones, tetrazanes, derived from the hypothetical nitro- 
 gen hydride NH 2 .NH.NH.NH 2 , have been obtained by the oxida- 
 tion of aldehyde-phenyl-hydrazones with HgO or amyl nitrite (B. 26, 
 R. 55 ; 27, 2920). Thus, from benzal-phenyl-hydrazone the compound 
 
 5 Benzal-diphenyl-dihydro-tetrazone is obtained, m.p. 
 
 g.5. . 
 
 190. Under the influence of other oxidisers, e.g. aerial oxygen in 
 alkaline solution, the aldehydrazones are oxidised to osazones of di- 
 ketones. Thus, benzal-hydrazone is oxidised to benzile-osazone (A. 
 305, 165). Concerning a third type of oxidation, producing the so- 
 
 called dehydro-benzal-phenyl-hydrazone ^S^ : ^S^S*, m.p. 207, see 
 C. 1897, II. 899 ; B. 34, 528, etc. 
 
168 ORGANIC CHEMISTRY 
 
 1 8. Buzylene or Diazo-hydrazo-compounds. In Hippuryl-phenyl- 
 buzylene C 6 H 5 N=N NH NHCO.CH 2 NHCOC 6 H 5 , m.p. 84, we have 
 a hippuric acid derivative of the unknown nitrogen hydride " buzylene " 
 NH=N NH NH 2 (B. 26, 1268). It is formed from hippuryl-hydra- 
 zin and diazo-benzol sulphate. From the same buzylene the Diazo- 
 benzol-phenyl-hydrazide C 6 H 5 N : N.N(C 6 H 5 ).NH 2 , m.p. 71 with decom- 
 position, is derived. It has been prepared (i) from diazo-benzol and 
 phenyl-hydrazin ; (2) from phenyl-hydrazin by oxidation with iodine 
 solution (/. pr. Ch. 2, 66, 336). By the first method a number of 
 nucleus-substituted derivatives have also been prepared. As the 
 unsym. hydrazins are converted into tetrazones, so these diazo-phenyl- 
 hydrazides are converted, by oxidation with MnO 4 K, into bodies con- 
 taining a chain of eight N atoms. 
 
 19. Octazones. Bis-diazo-benzol- diphenyl - tetrazone, tetraphenyl- 
 octazone C 6 H 5 N : N.N(C 6 H 5 )N : N.N(C 6 H 5 )N : NC 6 H 5 , m.p. 51 ; bis- 
 bromo-diazo-benzol-diphenyl-tetrazone, m.p. 60. These substances 
 decompose, and explode very easily (B. 33, 2741). 
 
 4. Aromatic Compounds of Phosphorus, Arsenic, Antimony, 
 Bismuth, Boron, Silicon, and Tin. 
 
 The phenyl derivatives of phosphorus, arsenic, antimony, bismuth, 
 boron, silicon, and tin are correlated to the aromatic nitrogen com- 
 pounds. Their chlorides are most suitable for the preparation of these 
 bodies, (i) They react with benzene at a red heat, hydrochloric acid 
 being eliminated ; (2) with benzene and aluminium chloride ; (3) 
 with mercury-diphenyl ; (4) with phenyl-magnesium bromide (B. 37, 
 4620) ; (5) with sodium and benzene chloride, or benzene bromide. 
 This class of derivatives is produced also (6) from alloys of the elements 
 with alkali metals and benzene haloids. 
 
 Special importance is attached, on account of their destructive 
 action upon trypanosomes, to a series of aromatic compounds of arsenic 
 which, being relatively but slightly poisonous, were found useful as 
 medicines in protozoic diseases. It was found that compounds con- 
 taining trivalent arsenic were much more effective than those con- 
 taining quinquivalent arsenic (like those of cacodylic acid, Vol. I.). 
 The monosodium salt of p-amido-phenyl-arsinic acid, known as "atoxyl," 
 is used therapeutically for fighting " sleeping sickness " and the 
 diamido-dioxy-arseno- benzol, in the form of its bichlorohydrate 
 " salvarsan " (P. Ehrlich-Hata 666) for fighting syphilis. 
 
 PHENYL-PHOSPHORUS COMPOUNDS. Michaelis in 1876 succeeded, 
 by the preparation of phosphenyl chloride, the substance for obtaining 
 phosphenyl derivatives, in overcoming the experimental difficulties 
 which opposed the union of the phenyl residue with phosphorus (A. 181, 
 265 ; 293, 193, 325 ; 294, i). Some phosphenyl compounds in com- 
 position correspond to known aromatic nitrogen-containing substances ; 
 the names of the respective phosphenyl bodies recall these : 
 
 Aniline, C 6 H 5 NH 2 C 6 H 5 PH 2 , Phenyl-phosphine 
 
 Nitro-benzol, C 6 H 5 NO 2 C 6 H 5 PO 2 , Phosphino-benzol 
 
 Azo-benzol, C 6 H 5 N : NC 6 H 5 C 6 H 5 P : PC 6 H 5 , Phospho-benzol. 
 
PHENYL-PHOSPHORUS COMPOUNDS 169 
 
 Phenyl-phosphine C 6 H 5 .PH 2 , phosphaniline, boiling at 160, is ob- 
 tained by the action of hydriodic acid and then alcohol upon phosphenyl 
 chloride C 6 H 5 .PC1 2 . It is a liquid possessing an extremely disagreeable 
 odour. When exposed to the air, it oxidises to phosphenyl oxide 
 C 6 H 5 .PH 2 O, a crystalline mass easily soluble in water. Phenyl- 
 phosphine combines with HI to the iodide C 6 H 5 .PH 3 I, out of which 
 water again separates phenyl-phosphine. 
 
 Phosphenyl chloride C 6 H 5 .PC1 2 , boiling at 225, with sp. gr. 1-319 
 (29) , is a strongly refracting liquid which fumes in the air. It is formed 
 (i) by conducting a mixture of benzene and PC1 3 vapours through tubes 
 heated to redness (A. 181, 280) ; (2) by heating mercury-diphenyl with 
 PC1 3 ; and (3) by the action of A1C1 3 upon benzene and PC1 3 . Aided by 
 this last reaction, the chloro-phosphine residue has also been introduced 
 into dimethyl-aniline (6.21,1497), and into phenol-alkyl ether (B. 27,2559). 
 It forms the tetrachloride C 6 H 5 .PC1 4 with chlorine ; this melts at 73. 
 With oxygen it yields the oxychloride C 6 H 5 .PC1 2 O, boiling at 250, and 
 with sulphur phosphenyl sulpho-chloride, boiling at 205 (130 mm.). 
 When the dichloride is heated with water, we obtain phenyl-hypophos- 
 phorous acid C 6 H 5 .PHO.OH, melting at 70, while the tetrachloride 
 forms phenyl-phosphinic acid C 6 H 5 .PO.(OH) 2 , which melts at 150. 
 
 p-Tolyl-phosphoro-chloride CH 3 [4]C 6 H 4 PC1 2 , forms a tetrachloride, 
 which forms with aniline tolyl-trianilido-phosphonium chloride CH 3 [4] 
 C 6 H 4 P(NHC 6 H 5 ) 3 C1, melting at 245. Sodium hydroxide converts the 
 latter into the hydroxide CH 3 C 6 H 4 P(NHC 6 H 5 ) 3 OH, melting at 240 
 (B. 28, 2214). 
 
 Phosphino-benzene C 6 H 5 PO 2 , melting at 100, is obtained from 
 phosphenyl oxychloride and phenyl-hypophosphorous acid (B. 25, 1747). 
 
 Phosphenyl chloride converts phenyl-phosphine into phospho- 
 benzol C 6 H 5 .P : P.C 6 H 5 , melting at 150 (B. 10, 812). 
 
 Diphenyl-phosphine chloride (C 6 H 5 ) 2 PC1, boiling at 320, is ob- 
 tained from phosphenyl chloride alone at 280, or with mercury-di- 
 phenyl at 220 (B. 21, 1505). W r ith phenol it yields phenoxyl-diphenyl- 
 phosphine (C 6 H 5 ) 2 POC 6 H 5 , boiling at 265-270 (62 mm.) (B. 18, 2118) ; 
 and with dilute sodium hydroxide : diphenyl-phosphine (C 6 H 5 ) 2 PH, 
 boiling at 280, and diphenyl-phosphinic acid (C 6 H 6 ) 2 PO.OH, melting 
 at 190 (B. 15, 801). 
 
 Triphenyl-phosphine (C 6 H 5 ) 3 P, melting at 75 and boiling about 
 360, is produced from C 6 H 5 .PC1 2 , and bromo-benzol, or from 
 PC1 3 and bromo-benzol by the action of sodium (B. 18, R. 562). It 
 combines with halogen alkyls to quaternary phosphonium salts; 
 with a-halogen ketones, such as chloracetone CH 3 COCH 2 C1, compounds 
 are formed, which easily pass into so-called phospho-keto-betai'ns 
 
 (C^kP/^V/O** (B. 32, 1566). It forms, with bromine, the di- 
 
 \L/JH.3 
 
 bromide (C 6 H 5 ) 3 PBr 2 , which is converted by water or alkalies into 
 the dihydroxide (C 6 H 5 ) 3 P(OH) 2 . At 100 this passes into the oxide 
 (C 6 H 5 ) 3 PO. The latter melts at 143 and boils above 360. It is also 
 obtained from C 6 H 5 MgBr and POC1 3 (C. 1904, II. 1638). Triphenyl- 
 phosphine oxide (C 6 H 5 ) 3 PO, is isomeric with phenoxyl-diphenyl-phosphine 
 (C 6 H 5 ) 2 POC 6 H 5 . Both compounds, in vapour density determina- 
 tions made with reduced pressure, yield values according with the 
 simple molecular formulas. Phosphorus, therefore, in the first body 
 
170 ORGANIC CHEMISTRY 
 
 is quinquivalent, and in the second it is trivalent (Michaelis and 
 La Coste, B. 18, 2118). 
 
 PHENYL-ARSENIC COMPOUNDS. Reactions, similar to those used 
 in obtaining the phenyl substitution products of phosphorus chloride, 
 have been used with arsenic, and the following bodies have been ob- 
 tained : Phenyl-arsenious chloride C 6 H 6 AsCl 2 ; Diphenyl-arsenious 
 chloride (C 6 H 5 ) 2 AsCl ; Triphenyl - arsin (C 6 Hg) 3 As ; Phenyl - arsinic 
 acid C 6 H 5 AsO(OH) 2 ; Diphenyl-arsinic acid (C 6 H 5 ) 2 AsOOH. 
 
 Arseno-benzol C 6 H 5 As : AsC 6 H 5 (A. 201, 191 ; 207, 195 ; 270, 139 ; 
 321, 141 ; B. 19, 1031 ; 25, 1521 ; 27, 263). p-Amido-phenyl-arsinic 
 acid, arsanilic acid NH 2 C 6 H 4 AsO(OH) 2 , brilliant white needles, m.p. 
 above 200, is formed besides p 2 -diamido-diphenyl-arsinie acid 
 (NH 2 C 6 H 4 ) 2 AsOOH, m.p. 232, by heating aniline arsenate to 190- 
 200 (B. 41, 2367). By reduction with HI and SO 2 the amido-phenyl- 
 arsinic acid passes into p-amido-phenyl-arsinic oxide NH 2 C 6 H 4 AsO. 
 2H 2 O, whereas with tin, and HC1, it passes into the yellow p 2 -diamido- 
 arseno-benzol NH 2 C 6 H 4 As : AsC 6 H 4 NH 2 , m.p. 140 (C. 1909, 1. 963). 
 
 From arsanilic acid, through the diazo-compound, p-oxyphenyl- 
 arsinie acid HOC 6 H 4 As(OH) 2 , m.p. 174 is formed. This can also be 
 obtained direct by heating phenol with arsenic acid (C. 1909, I, 807). 
 On nitrifying and reducing this to m-amido-p-oxy-phenyl-arsinic acid 
 HO(NH 2 )C 6 H 3 AsO(OH 2 ), the m, m-diamido-p, p-dioxy-arseno-benzol 
 HO(NH 2 )C 6 H 3 As : AsC 6 H 3 (NH 2 )OH is obtained, the dichlorohydrate 
 of which is the before-mentioned salvarsan. For homologous amido- 
 phenyl-arsinic acids and their transformation products, see B. 41, 3859. 
 
 Triphenyl-stibin (C 6 H 5 ) 3 Sb, m.p. 48, is produced on introducing 
 sodium into a solution of chloro-benzol and of antimonious chloride in 
 benzene (A. 233, 43). Also from C 6 H 5 MgBr and SbCl 2 (B. 37, 4621). 
 On heating with antimonious chloride in xylol, it yields phenyl-stibinous 
 chloride, m.p. 58, b.p. 290, starting from which, the oxide, sulphide, 
 tetrachloride, and phenyl-stibinic acid have been prepared (B. 31, 
 2910). Triphenyl-stibin sulphide (C 6 H 5 ) 3 SbS, m.p. 120, from triphenyl- 
 stibin bromide with Am 2 S (B. 41, 2762). 
 
 Bismuth-triphenyl (C 6 H 5 ) 3 Bi, m.p. 78, is prepared by heating 
 bromo-benzol and bismuth sodium (A. 251, 324). Diphenyl-bismuth 
 iodide (C 6 H 5 ) 2 BI, m.p. 133 (B. 30, 2843). 
 
 PHENYL-BORON COMPOUNDS. Phenyl-boron chloride C 6 H 5 BC1 2 , m.p. 
 o, and b.p. 175, and diphenyl-boron chloride (C 6 H 5 ) 2 BC1, b.p. 271, 
 result from the interaction of mercury-diphenyl and boron chloride. 
 Phenyl-boron bromide C 6 H 5 BBr, m.p. 330, b.p. 20 100. Diphenyl- 
 boron bromide (C 6 H 5 ) 2 BBr, m.p. 25 (B. 27, 244 ; A. 315, 29). 
 
 PHENYL-SILICON COMPOUNDS. Phenyl-silico-chloride C 6 H 5 .SiCl 3 
 is prepared by heating mercury-diphenyl and SiCl 4 to 300. It boils 
 at 197 (Ladenburg, A. 173, 151). Water decomposes it into silico- 
 benzoic acid C 6 H 5 .SiO.OH, m.p. 92. Alcohol forms ortho-silico- 
 benzoic acid ester C 6 H 5 .Si(O.C 2 H 5 ) 3 , b.p. 137. Zinc ethyl converts 
 the chloride into triethyl-phenyl silicide C 6 H 5 .Si.(C 2 H 5 ) 3 , b.p. 230. 
 Triphenyl-methyl silicide (C 6 H 5 ) 3 SiCH 3 , m.p. 67, and triphenyl-ethyl 
 silicide (C 6 H 5 ) 3 SiC 2 H 5 , m.p. 76, are obtained from triphenyl-silico- 
 chloride (C 6 H 5 ) 3 SiCl with methyl- and ethyl-magnesium iodide respect- 
 ively (C. 1908, I. 1266). Mixed alkyl-silicon compounds with four 
 different radicles, like phenyl-methyl-ethyl-propyl-silicon C 6 H 5 SiCH 3 
 
PHENYL METAL DERIVATIVES 171 
 
 (C 2 H 5 )(C 3 H 7 ), a liquid of b.p. 231, are formed by treating silicon 
 chloride successively with phenyl, methyl, ethyl, and propyl magnesium 
 bromides (C. 1907/1. 1192). Concerning optically active silicon com- 
 pounds, see C. 1908, 1. 1688 ; 1909, 1. 360 ; 1910, 1. 2083. 
 
 Triphenyl-silicane (C 6 H 5 ) 3 SiH, m.p. 203 (B. 40, 2278). 
 
 Tetraphenyl-silicon Si(C 6 H 5 ) is produced by the action of sodium 
 upon a mixture of SiQ 4 , chloro-benzol, and ether (B. 19, 1012). It 
 melts at 228 and boils above 300. On heating with bromine it yields 
 triphenyl-silicon bromide (C 6 H 5 ) 3 SiBr, m.p. 120, which on boiling 
 with potash solution becomes triphenyl-silicol (C 6 H 5 ) 3 SiOH, m.p. 155 
 (C. 1899, II. 57; 1901, I. 999 ; B. 40, 2275). Diphenyl-silieol (C 6 H 5 ) 2 
 Si(OH) 2 , m.p. 139, on melting, passes into trimolecular diphenyl-silieon 
 [(C 6 H 5 ) 2 SiO] 3 , m.p. 110 (C. 1904, I. 1257). 
 
 PHENYL-TIN COMPOUNDS. Mercury diphenyl and stannic chloride 
 interact to form tin-diphenyl chloride (C 6 H 5 ) 2 SnCl 2 , m.p. 42 (A. 194, 
 145 ; 282, 328). 
 
 Tin-tetraphenyl Sn(C 6 H 5 ) 4 is produced by the action of tin-sodium 
 upon bromo-benzol, m.p. 226 and b.p. above 420 (B. 22, 2917). 
 Also by the action of tin tetrachloride upon phenyl-magnesium bromide. 
 
 5. Phenyl Metal Derivatives. 
 
 The phenyl group has been combined with magnesium, mercury, 
 and lead. 
 
 Magnesium-diphenyl (C 6 H 5 ) 2 Mg, is a light, yellowish-white powder, 
 dissolving readily in a mixture of benzene and ether. It is produced 
 on heating mercury-diphenyl with magnesium powder and some acetic 
 ester to i8o-i85 (A. 282, 320). In air it undergoes spontaneous com- 
 bustion ; water decomposes it violently with formation of Mg(OH) 2 
 and benzene. 
 
 ARYL-MAGNESIUM HALOIDS. Phenyl-magnesium bromide C 6 H 5 
 MgBr, and phenyl-magnesium iodide CgHgMgl, as well as homo- 
 logous aryl-magnesium haloids, are formed in a manner analogous to 
 the alkyl-magnesium haloids, by the action of magnesium upon the 
 etheric solutions of bromine and iodine benzols. They are as suitable 
 for synthetic reactions as are the alkyl-magnesium haloids : 
 
 (i) With CO 2 they unite to form salts of aromatic carboxylic acids, 
 e.g. C 6 H 5 COOH. (2) With 'COS they form thiol-carboxylic acids 
 C 6 H 5 COSH, besides triphenyl-carbinols (C 6 H 5 ) 3 COH. (3) With CS 2 , 
 carbo-thio-acids are formed, e.g. C 6 H 5 CSSH. (4) Triphenyl-carbinol 
 is formed from C 6 H 5 MgBr with phosgene and benzoic ester. (5) With 
 mustard oils, thio-anilides are formed, CH 3 CSNHC 6 H 5 . (6) With iso- 
 nitriles, alkylated aldehydimines C 6 H 5 CH=NCH 3 . (7) With diazo- 
 benzol-imide C 6 H 5 N 3 , diazo-amido-benzol C 6 H 5 N 2 NHC 6 H 5 . (8) The 
 action of nitroxyl chloride upon phenyl-magnesium bromide produces 
 nitroso-benzol. (9) With S and Se, thio-phenols and seleno-phenols 
 are formed, C 6 H 5 SH, and C 6 H 5 SeH. (10) With iodine, iodo-benzol 
 and MgBrl, etc. (C. 1901, I. 1357 ; 1903, I. 568, 1403 ; 1909, II. 1349 '> 
 B. 35, 2692 ; 36, 587, 910, 1007, 1588, 2116 ; 37, 875 ; 39, 3219). 
 
 Mercury-diphenyl (C 6 H 5 ) 2 Hg, m.p. 120, is formed by treating 
 bromo-benzol in benzene solution for some time with liquid sodium 
 amalgam (Otto and Dreher, A. 154, 93) ; the addition of some acetic 
 
172 ORGANIC CHEMISTRY 
 
 ether facilitates the reaction. It is also obtained by the action of 
 HgCl 2 or HgCl upon phenyl-magnesium bromide (B. 37, 1127). It 
 crystallises in colourless, rhombic prisms, and can be sublimed. It 
 assumes a yellow colour in sunlight. It dissolves readily in benzene 
 and carbon disulphide, but with more difficulty in ether and alcohol ; 
 in water it is insoluble. When distilled, it decomposes for the most part 
 into diphenyl, benzene, and mercury. The action of sodium upon 
 mercury-diphenyl in benzene solution, produces sodium amalgam and 
 sodium-phenyl C 6 H 5 Na, a body capable of many reactions (C. 1903, 
 II. 195). Acids decompose it, with formation of benzene and mercury 
 salts. Haloid compounds are produced by the action of the halogens 
 e.g. mereury-phenyl chloride C 6 H 5 HgCl, m.p. 250 ; mercury-phenyl 
 bromide C 6 H 5 HgBr, m.p. 275 ; mercury-phenyl iodide C 6 H 5 HgI, 
 m.p. 265. Mercury-phenyl hydroxide C 6 H 5 HgOH is produced when 
 silver oxide and alcohol act upon the chloride (/. pr. Ch. I. 186). 
 
 Mercury-phenyl acetate C 6 H 5 Hg.O.COCH 3 is also formed direct 
 by heating benzene with mercury acetate to iio-i2O. Similarly, 
 the mercury atom is easily introduced in the place of the nuclear H 
 atom in other aromatic compounds, such as nitro-benzols, anilines, 
 phenols, benzoic acid, etc., so that we may speak, not only of chlorina- 
 tion, nitrogenation, and sulphuration, but also of a " mercuration " 
 of aromatic substances, as a general reaction. In these combinations 
 the mercury is rather firmly attached to the nucleus. When the action 
 is strong, several H atoms are replaced, and we may obtain compounds 
 like C 6 H 4 (Hg.OCOCH 3 ) 2 , C 6 H 3 (HgO.COCH 3 ) 3 , and C 6 H 2 (HgO.COCH 3 ) 4 
 (B. 35, 2032, 2853 ; C. 1899, 1- 734 ; 1900, I. 1097). 
 
 Mercury-dialphyls. See A. 173, 162 ; B. 14, 2112 ; 17, 2374 ; 20, 
 1719 ; 22, 1220, etc. 
 
 Lead-tetraphenyl (C 6 H 5 ) 4 Pb is formed by heating bromo-benzol 
 with lead-sodium and acetic ester. It melts at 224 (B. 20, 3331). 
 Also from lead chloride, and phenyl-magnesium bromide (B. 37, 1126). 
 
 6. Sulphonic Acids. 
 
 The ease with which sulphonic or sulpho-acids are produced dis- 
 tinguishes the aromatic hydrocarbons from the aliphatic compounds 
 in the same manner as does the easy formation of nitro-compounds. 
 The introduction of sulpho-groups, in the place of aromatic H atoms, 
 is called " sulphonation." 
 
 Formation. (i) The sulpho-acids of benzene hydrocarbons, and 
 other benzene derivatives, are easily produced by mixing or heating 
 them with concentrated or fuming sulphuric acid. In this manner it 
 is possible to combine three sulpho-groups with one benzene nucleus : 
 
 C 6 H 6 +HO.S0 3 H *= C 6 H 5 .SO 3 H+H 2 0. 
 
 (2) In the action of an excess of chloro-sulphonic acid C1.SO 2 OH 
 the principal products, with careful cooling, are the chlorides of the 
 sulpho-acids (B. 12, 1848 ; 28, 2172). The reaction then proceeds in 
 the following way (B. 22, R. 739) : 
 
 C 6 H 6 +C1S0 2 OH = HC1 +C 6 H 5 .S0 2 OH 
 C 6 H 5 S0 2 OH+C1S0 2 OH = H 2 SO 4 +C 6 H 6 SO 2 C1. 
 
 Sulphones are secondary products (p. 182). 
 
SULPHONIC ACIDS 173 
 
 (3) Further, sulphonic acids can be obtained from the diazo-amido- 
 derivatives by boiling with sulphurous acid. 
 
 (4) By the oxidation of thio-phenols. This reaction proves that the 
 sulphur atom of the sulpho-group is in union with the aromatic nucleus 
 (compare mercaptans). 
 
 (5) By the oxidation of sulphinic acids. 
 
 Properties and Transformations. Many aromatic sulpho-acids are 
 very soluble in water and crystalhse with difficulty. They can be sepa- 
 rated from aqueous solution in the form of their sodium salts by means 
 of sodium chloride : salting out (B. 28, 91). In a cathode-ray vacuum 
 many sulpho-acids can be distilled without decomposition (B. 33, 
 3207). The ready solubility of the sulpho-acids, in conjunction with 
 their easy production, meets with an important technical application 
 in the conversion of aromatic dyes insoluble in water into their 
 sulpho-acids, which dissolve in water with ease. 
 
 (1) The chlorides of the acids are made by acting upon the alkali 
 salts with POC1 3 and PC1 5 , and from the acids themselves by the action 
 of PC1 5 . The chlorides are converted into amides, esters, etc., as in- 
 dicated under the alkyl-sulphonic acids (Vol. I.). The esters of the 
 sulpho-acids are transposed by alcohol at I40-I50, with the pro- 
 duction of ethers (Vol. I.). Heating with phenols and with amines 
 also makes the benzol-sulphonic esters transfer their alkyl groups to 
 the former, so that they are generally useful as means of alkylation 
 (A. 327, 120). The sulphonamides are stable and crystallise well ; they 
 are frequently prepared for the characterisation of a sulpho-acid. 
 
 (2) Hydrocarbons (together with phenyl sulphones) are formed 
 when the free acids are subjected to distillation : 
 
 C 6 H 5 .S0 3 H = C 6 H 6 +S0 3 . 
 
 This rupture is more easily accomplished by heating the acids with 
 concentrated HC1 to 150, or by distilling the ammonium salt of the 
 sulphonic acid, or a mixture of the lead salt with ammonium chloride 
 (B. 16, 1468). The decomposition results with least difficulty by con- 
 ducting steam into the dry sulpho-acid, or its solution in concentrated 
 sulphuric acid ; superheated steam is most effective (B. 19, 92). 
 
 (3) The SO 2 C1 group in the sulpho-chlorides can be replaced by 
 chlorine through the action of PC1 5 . In some sulphonic acids free 
 chlorine and bromine are capable of eliminating the sulpho-group and 
 introducing the halogens (B. 16, 617). 
 
 (4) The sulpho-group in many sulphonic acids is often replaced by 
 NO 2 upon treating them with concentrated nitric acid. 
 
 (5) The sulphonic acids of the alkyl-benzols, more frequently applied 
 in the form of their sulphamides, yield sulpho-carboxylic acids upon 
 oxidation. The oxidation of o-toluol-sulphamide to the sulphimide 
 of o-sulpho-benzoic acid (q.v.), called saccharin, is technically im- 
 portant. 
 
 (6) The chlorides of the aromatic sulpho-acids become thio-phenols 
 upon reduction (cp. C. 1900, I. 252 ; 107, II. 397) : 
 
 C 6 H 5 S0 2 C1+6H = C 6 H 5 SH+2H 2 0+HC1. 
 This reaction, like that of the oxidation of thio-phenols to sulphonic 
 
174 ORGANIC CHEMISTRY 
 
 acids, demonstrates that in the sulphoacids the sulphur is in immediate 
 union with the benzene nucleus. 
 
 (7) The sulphonic acids are not decomposed upon boiling them with 
 aqueous alkalies. Phenols are formed when they are fused with alkalies. 
 This reaction serves for the technical preparation of resorcin and other 
 phenols : 
 
 C 6 H 6 .S0 3 K+KOH == C 6 H 5 .OH+S0 3 K 2 . 
 
 (8) When distilled with potassium cyanide (or dry yellow prussiate 
 of potash) nitriles result : 
 
 C 6 H 5 .S0 3 K+CNK = C 6 H 5 .CN+S0 3 K 2 , 
 
 and these may be readily saponified to carboxylic acids. 
 
 (9) Carboxylates are also obtained on fusing the alkali -sulphonates 
 with sodium formate. 
 
 (10) Melting sulpho-acids with Na amide yields anilines (B. 19, 903 ; 
 39, 3014) : 
 
 C 6 H 5 S0 3 Na+NaNH 2 - C 6 H 5 NH 2 +SO 3 Na 2 . 
 
 MONOSULPHONIC ACIDS. Benzol-sulphonie acid C 6 H 5 .SO 3 H, m.p. 
 66, b.p. I35-I37, crystallises from water, in which it is exceedingly 
 soluble, in plates containing water of crystallisation. 
 
 The barium salt (C 6 H 5 .SO 3 ) 2 Ba+H 2 O forms pearly flakes, and is 
 sparingly soluble in alcohol. 
 
 The chloride C 6 H 5 .SO 2 C1, m.p. 14-5, b.p. 116 (B. 25, 2257; 
 C. 1900, I. 252), has a specific gravity of 1*378 at 23. It slowly 
 reverts to the acid upon boiling with water. 
 
 Methyl ester, b.p. 20 154 (C. 1903, I. 396). 
 
 The ethyl ester, b.p. 15 156, obtained by the action of ethyl alcohol 
 on the chloride, is decomposed into benzol-sulphonic acid and ethyl 
 ether (Vol. I.) when it is heated to 150 with ethyl alcohol. 
 
 Benzol-sulphamide C 6 H 5 .SO 2 .NH 2 , m.p. 150. 
 
 Benzol-sulphone-anilide C 6 H 5 SO 2 NHC 6 H 5 , m.p. 110. The benzol- 
 sulphamides of the primary bases are mostly soluble in alkali ; their 
 behaviour towards benzol sulpho-chloride may therefore be used for 
 determining whether an amine base is primary or secondary (cp. B. 33, 
 477 ; 38, 906). Concentrated sulphuric acid splits up the benzol- 
 sulphonamides into their components (A. 367, 157). 
 
 Dibenzol-sulphimide (C 6 H 5 SO 2 ) 2 NH, from sodium-benzol-sulphimide 
 with benzol sulpho-chloride (C. 1901, II. 1185). Benzol-sulpho-dichlor- 
 amide C 6 H 5 SO 2 NC1 2 , m.p. 76, is formed by the action of sodium hypo- 
 chlorite upon benzol-sulphamide. The latter is regenerated by HC1 
 and HI, with liberation of chlorine and iodine. With alkalies in the 
 cold, salts of benzol-sulpho-monochloramide are formed in which 
 the alkali is probably linked to oxygen : C 6 H 5 SO(OK) : NCI (C. 1905, 
 I. 1010). 
 
 Benzol-sulpho-nitramide C 6 H 5 SO 2 NHNO 2 consists of colourless 
 plates, readily soluble in water. It decomposes at 100 into benzol- 
 sulphonic acid and nitrous oxide. It is formed when a mixture of 
 nitric and sulphuric acids acts upon benzol-sulphamide. Its potassium 
 salt C6H 5 SO 2 NK.NO 2 , m.p. 275, when reduced by glacial acetic acid 
 and zinc dust becomes benzol-sulphono-hydrazide C 6 H 6 SO 2 NH.NH 2 , 
 
SULPHONIC ACIDS 175 
 
 m.p. 105 with decomposition, which also form benzol sulpho-chloride 
 with hydrazin hydrate. 
 
 Benzol-sulphone-phenyl-hydrazide, phenyl-benzol-sulphazide (see 
 above). Dibenzol - sulphone - hydrazin (C 6 H 5 S0 2 .NH) 2 , m.p. 228. 
 Benzol-sulphone-azode C 6 H 5 SO 2 .N 3 , an oil, is, in contrast with car- 
 boxylic azides, not attacked by hot water or alcohol (/. pr. Ch. 
 2, 58, 160). 
 
 The sulphamide and nitrous acid yield dibenzol-sulphon-hydroxyl- 
 amine (C 6 H 5 SO 2 ) 2 NOH, which can also be made by the interaction of 
 benzol-sulphinic acid and sodium nitrite ; with diazo-benzol chloride 
 the product is benzol-sulpho-diazo-benzol-amide C 6 H 5 SO 2 NH N = 
 N.C 6 H 5 , m.p. 101 (B. 27, 598). 
 
 Benzo - sulpho - hydroxamic acid C 6 H 5 SO 2 .NHOH, m.p. 126, is 
 obtained from benzol-sulpho-chloride and hydroxylamine. Alkalies 
 decompose it into benzol-sulphinic acid and hyponitrous acid (B. 29, 
 1559, 2324) : 
 
 2C 6 H 5 SO 2 NHOH+4KOH = 2C 6 H 5 SO 2 K-f (NOK) 2 +4H 2 O. 
 
 With aldehydes, benzo-sulpho-hydroxamic acid passes into benzol- 
 sulphinic acid and carbo-hydroxamic acids (C. 1901, II. 99). 
 
 Benzol-sulpho-isoeyanate C 6 H 5 SO 2 NCO, b.p. 9 130, from benzol- 
 sulpho-chloride and silver cyanate. An oil of feeble odour, exhibiting 
 all the properties and transformations of the isocyanates (B. 37, 690). 
 
 TOLUOL-SULPHONIC ACIDS. In sulphonating, toluol-o- and p-acids 
 are the chief products. The o-acid can be obtained from p-tolyl- 
 hydrazin-o-sulphonic acid free from the p-acid. The m-acid is obtained 
 from p-toluidin-m-sulphonic acid. o-Toluol-sulpho-chloride is a 
 liquid, formed from o-toluol-sulphinic acid and Cl (C. 1901, II. 961 ; 
 B. 38, 730). o-Toluol-sulphamide melts at 155 (see o-Sulpho-benzoic 
 acid), m- Toluol -sulphonic acid CH 3 [i]C 6 H 4 [3]SO 3 H+H 2 O ; its 
 chloride is a liquid ; its amide melts at 107. p-Toluol-sulphonic acid 
 CH 3 [i]C 6 H 4 [4]SO 3 H+4H 2 O ; melts at 35, b.p. 147 ; its chloride melts 
 at 69, and boils at 145 (15 mm.) ; its bromide melts at 96, its 
 iodide at 84, and its amide at 137. Methyl ester, m.p. 28; ethyl 
 ester, m.p. 33 (A. 327, 121). 
 
 Ditoluol-sulpho-hydroxamic acid (C 7 H 7 .SO 2 ) 2 NOH melts with 
 decomposition at 148. It results from the action of sodium nitrite 
 upon toluol-sulphinic acid. It combines with an additional molecule 
 of the sulphinic acid to tritoluol-sulphonamide (C 7 H 7 .SO 2 ) 3 N, melting at 
 I 9 (/ P r - Ch. 2. 54, 95 ; C. 1901, I. 455). Further derivatives of 
 p-toluol-sulphonic acid, see B. 34, 2996. v 
 
 XYLOL-SULPHONIC ACIDS. 1, 2-Xylol-4-sulphonie acid : its chloride 
 melts at 51, its amide at 144. 1, 3-Xylol-4-sulphonic acid : its chloride 
 melts at 34, and its amide at 137. 1, 3-Xylol-2-sulphonic acid : its 
 amide melts at 95. 1, 4>-Xylol-3-sulphonic acid : its chloride melts at 
 25, and its amide at 247. They result upon sulphonating the various 
 xylols. 
 
 [1, 2, 4]-Pseudo-eumol-5-sulphonie acid (CH 3 ) 3 C 6 H 2 SO 3 H+2H 2 O 
 melts at 111. Its chloride melts at 61, and the amide at 181. Mesity- 
 lene-sulphonic acid C 9 H 12 SO 3 +2H 2 O melts at 77, its chloride at 57, 
 and its amide at 141. 
 
176 ORGANIC CHEMISTRY 
 
 POLY-SULPHONIC ACIDS. Benzol - disulphonic acids C 6 H 4 / S 3H . 
 
 \SO 3 H 
 
 On heating benzene with fuming sulphuric acid to 200 C., we get meta- 
 and ^>flra-benzol-disulphonic acids, with the former in predominating 
 quantity, but by prolonged heating it passes into the para-variety 
 (B. 9, 550). Meta-disulphonic acid is produced from disulphanilic acid 
 by means of the diazo-compound. 
 
 Ortho-benzol-disulphonic acid is formed from meta-amido-benzol- 
 sulphonic acid by further introduction of the sulpho-group, and replace- 
 ment of NH 2 by hydrogen. The melting-points of the sulpho-chlorides 
 and sulphamides of the three isomeric disulphonic acids are : 
 
 Ortho. Meta. Para. 
 
 C a H 4 (S0 2 Cl) 2 105 63 132 
 
 C 6 H 4 (S0 2 NH 2 ) 2 233 228 288. 
 
 The corresponding dicyanides, CeH 4 (CN) 2 , the nitriles of the three 
 phthalic acids, are obtained by distillation with potassium cyanide or 
 potassium ferrocyanide. When fused with potassium hydroxide, both 
 meta and para acids yield resorcin (meta-dioxy-benzol) ; at lower tem- 
 peratures meta-phenol-sulphonic acid C 6 H 4 (OH)SO 3 H results at first 
 from both acids. 
 
 Benzol- trisulphonic acid C 6 H 3 (SO 3 H) 3 (i, 3, 6) is easily made 
 by heating potassium m-benzol disulphonate with common sulphuric 
 acid (B. 21, R. 49). The free acid (from the lead salt) crystallises in 
 long needles with 3H 2 O ; its chloride melts at 184, its amide at 306. 
 Fused with caustic potash, it yields phloroglucin C 6 H 3 (OH) 3 , or i, 3, 5- 
 trioxy-benzol ; and upon heating with potassium cyanide it forms 
 the trinitrile, which upon saponification becomes trimesinic acid 
 C 6 H 3 (C0 2 H) 3 . 
 
 Toluol-disulphonie acids. The six possible isomerides are known 
 (B. 20, 350 ; 29, R. 868). 
 
 Xylol-disulphonie acids (B. 25, R. 700). 
 
 Benzol-seleno-aeid C 6 H 5 SeO 2 OH, hygroscopic needles, m.p. 142, 
 is formed by heating benzene with selenic acid to ioo-no, as well as 
 by oxidation of phenyl-diselenide with chlorine water. It detonates 
 on heating to 180, yielding oxygen, phenyl-selenide, and phenyl- 
 diselenide. Reduction with SH 2 or SO 2 converts it into seleno-phenol. 
 With concentrated HC1 it develops Cl, even in the cold, being reduced 
 to benzol-seleninic acid (C. 1909, II. 20). 
 
 CHLORO-, BROMO-, IODO-, IODOSO-, NITRO, NITROSO- and AMIDO 
 BENZOL-SULPHONIC ACIDS. The chloro-, bromo- and iodo-benzol- 
 sulphonic acids are prepared from the three amido-benzol-sulphonic 
 acids by means of the diazo-reactions (B. 28, 90). p-Compounds are 
 the principal products in the sulphonation of chloro- and bromo- 
 benzols. In nitrating benzol-sulphonic acid and sulphonating nitro- 
 benzol the three isomeric nitro-benzol-sulphonic acids are produced 
 with the m-derivatives in predominating quantity (A. 177, 60). 
 
 o- and p-Nitro-benzol-sulphonic acids are best prepared by oxida- 
 tion of the corresponding nitro-benzol-disulphides (NO 2 C6H 4 S) 2 , 
 obtained from the nitro-chloro-benzols, with fuming sulphuric acid 
 (B. 35, 651 ; C. 1903, I. 508). 
 
SULPHONIC ACIDS 
 
 177 
 
 The following table contains the melting-points of the chlorides and 
 amides of the acids : 
 
 
 ORTHO. 
 
 META. 
 
 PARA. 
 
 Chloride. 
 
 Amide. 
 
 Chloride. 
 
 Amide. 
 
 Chloride. 
 
 Amide. 
 
 Chloro-sulpho- . 
 Bromo-sulpho- . 
 lodo-sulpho- 
 Nitro-sulpho- . 
 
 28 
 
 g 
 
 67 
 
 188 
 186 
 170 
 1 86 
 
 Oil 
 Oil 
 
 23 
 60 
 
 148 
 
 154 
 152 
 161 
 
 53 
 75 
 84 
 Oil 
 
 143 
 166 
 183 
 181 
 
 o-Iodo-chloride-benzol sulpho-chloride ICl 2 [2]C 6 H 4 [i]SO 2 Cl, m.p. 
 60, is converted by sodium hydroxide into iodoso-benzol-sulphonic 
 acid (B. 28, 95). 
 
 m-Nitroso-benzol-sulphonic acid (B. 25, 75). 
 
 Amido-benzol-sulphonie acids. (i) On sulphonating aniline at 
 180 with fuming sulphuric acid (8-10 per cent. SO 3 ), the p-derivative 
 constitutes the chief product. It is sulphanilic acid, important in the 
 technology of dyes, and was discovered in 1845 by Gerhardt. The 
 second sulpho-group enters the o-position with the formation of 
 l-aniline-2, 4-disulphonic acid or disulphanilic acid ; a trisulphonic 
 acid is not produced (B. 23, 2143). 
 
 Amido-benzol-sulphonic acids are also produced (2) by reduction 
 of nitro-benzol-sulphonic acids ; (3) by heating chloro-benzol-sulphonic 
 acids with ammonia in the presence of copper salts (C. 1909, I. 477). 
 (4) The sodium salts of phenyl-sulphaminic acids, on being heated to 
 i7O-i8o, transpose themselves into amido-benzol-sulphonates (C. 
 1907,1.1792). 
 
 The amido-benzol-sulphonic acids, like glycocoll and taurine, can be 
 
 /-SO 2 O 
 regarded as cyclic ammonium salts, C 6 H 4 <' I 
 
 \NH 3 ' 
 
 The three amido-benzol-sulphonic acids dissolve with difficulty in 
 water, alcohol, and ether. The (ortho)-a.cid either crystallises in an- 
 hydrous rhombohedra or in four-sided prisms containing JH 2 O ; these 
 do not effloresce. It is best prepared by the reduction of p-bromo- 
 aniline-o-sulphonic acid (B. 28, R. 751 ; 29, 1075 ; C. 1903, I. 508). 
 
 The (wta)-acid, called metanilic acid, and also important in the 
 technology of dyes, crystallises in delicate needles or in prisms with 
 i|H 2 O, which effloresce. 
 
 p-Sulphanilic acid crystallises from hot water in rhombic plates 
 with i molecule H 2 O ; these effloresce in air. They are soluble in 
 112 parts H 2 O at 15 (B. 14, 1933). It yields a considerable quantity 
 of quinone when oxidised with MnO 2 and H 2 SO 4 or chromic acid. It 
 yields aniline and not amido-phenol when fused with caustic potash ; 
 unlike its isomerides, it is readily converted by bromine water into 
 tribromo-aniline (B. 29, R. 309). 
 
 The sodium-amido-benzol-sulphonates yield acetyl derivatives with 
 acetic anhydride (B. 17, 708 ; 39, 1561), whereas the free acids are 
 
 VOL. II. N 
 
178 ORGANIC CHEMISTRY 
 
 not in condition to do this. This fact argues for the ammonium-salt 
 formula of the free acids. 
 
 In the o- and p-amido-benzol-sulphonic acids the sulpho-group is 
 replaced by the nitro-group under the action of nitric acid, nitranilines 
 being produced (A. 339, 202). 
 
 p-Phenylene-diamido-monosulphonic acid C 6 H 3 (SO 3 H)(NH 2 ) 2 is 
 produced by heating p-dichloro-benzol-sulphonic acid with ammonia 
 in the presence of copper bronze (C. 1908, II. 1307). 
 
 Toluylene-diamido-sulphonic acids, see C. 1904, I. 1410. 
 
 Diazo-benzol-sulphonic-acid anhydrides, cyclic diazides. Nitrous 
 acid transforms the three amido-benzol-sulphonic acids into the an- 
 hydrides of the diazo-benzol-sulphonic acids (cp. C. 1898, I. 293) : 
 
 2 
 2 OH C H4 \N 2 / C 
 
 Diazo-benzol-sulphonic acid Anhydride. 
 
 The hydrated sulpho-acids are not known ; they pass at once into 
 anhydrides. The dipotassium and the disodium salts of the o- and 
 p-diazo-benzol-sulphonic acids, C 6 H 4 (S0 3 Me)(N 2 OMe), exist each in 
 two forms, one of which belongs to the normal and the other to the 
 iso-diazo-series. The iso-salts are produced on digesting the normal 
 salts ; they give up nitrogen less readily, and do not combine, or at 
 least with difficulty, with aromatic amines or phenols, to yield azo- 
 dyes (B. 29, 1059, 1388). Primary potassium-iso-diazo-sulphonate 
 C 6 H 4 (SO 3 K)N 2 OH-|-H 2 O results on treating the corresponding 
 dipotassium salt with acetic acid (B. 28, 1386). 
 
 It is rather remarkable that, while otherwise it is only the ortho- 
 compounds of the benzene di-derivatives which form inner anhydrides, 
 all three of the diazo-benzol-sulpho-acids are capable of anhydride forma- 
 tion. They exhibit all of the reactions- of the diazo-compounds. 
 
 The diazide of sulphanilic acid, p-diazo-benzol-sulphonic acid, con- 
 sists of sparingly soluble white needles ; although relatively stable for 
 a diazo-body, it sometimes explodes spontaneously (B. 34, n). Heated 
 with absolute alcohol, it forms benzol- sulphonic acid ; with water the 
 diazo-acid becomes p-phenol-sulphonic acid ; while with potassium 
 sulphide the dipotassium salt of p-thio-phenol-sulphonic acid results. 
 Concerning the effect of bleaching-lime upon diazo-benzol-sulphonic 
 acids, see A. 330, I. 
 
 Amido-azo-benzol-sulphonic acids. The diazides of sulphanilic 
 acid and metanilic acid are used in the manufacture of sulphurised 
 azo-dyes. The first group of this great class of dyes has received 
 mention ; it comprises the amido-azo-compounds, which are insoluble 
 or dissolve with difficulty in water. Upon introducing the sulpho- 
 group into the amido-azo-derivatives it will be discovered that the 
 solubility in general increases with the number of sulpho-groups. The 
 alkali salts of the amido-azo-benzol-sulphonic acids constitute the 
 dyes soluble in water. We shall meet with other groups of azo-dyes 
 when we study the phenols : oxyazo-compounds. The naphthalin-azo- 
 compounds and the benzidin dyes, containing the diphenyl residue, 
 are especially important. 
 
 Arbitrary names are assigned these dyes, with the addition of the 
 letters Y (yellow), O (orange), and R (red), whose number approxi- 
 
SULPHONIC ACIDS 179 
 
 mately expresses the intensity of the colour. They colour wool and 
 silk directly, cotton after it has been mordanted. 
 
 Formation. (i) The amido-azo-bodies are sulphurised. (2) The 
 diazides of sulphonic acids are combined with bases. 
 
 Upon sulphonating amido-azo-benzol there results a mixture of 
 amido-azo-benzol-mono- and disulphonic acids, known in commerce 
 under the names acid yellow or pure yellow : SO 3 H[4]C 6 H 4 (i)N= 
 N[i']C 6 H 4 [ 4 ']NH 2 and SO 3 H[ 4 ]C 6 H 4 [i]N=:N[i']C 6 H3[4']NH 2 [3']SO3H 
 (B. 22, 847). Being amido-bodies, the sulpho-acids are themselves 
 capable again of diazotising and combination, whereby very valuable 
 dyes have been obtained (compare Biebrich scarlet). Amido-azo- 
 benzol-trisulphonic acid, see B. 33, 1366. 
 
 The following azo-dyes have been made by combining the diazide 
 of sulphanilic acid with dimetnyl-aniline and diphenyl-amine, and the 
 diazide of metanilic acid with diphenyl-amine : 
 
 [4'>Dimethyl-amido-azo-benzol- [4] -sulphonic acid SO 3 H[4]C 6 H 4 
 [i]N=N[i]C 6 H 4 [4']N(CH 3 ) 2 , melting at 115, consists of golden-yellow 
 flakes (B. 10, 528 ; 12, 1490 ; 41, 1187). Its sodium salt, as a dye, 
 bears the names tropceolin O, orange III, and helianthin. It serves as 
 a delicate indicator in alkalimetry ; mineral acids convert the alkaline 
 orange-coloured solution into pink. CO 2 , H 2 S, and acetic acid do not 
 act on it in the cold (Ch. Z., VI. 1249 ' B- 18, 3290). By reduction 
 helianthin yields sulphanilic acid and para-amido-dimethyl-aniline. 
 Fuming nitric acid splits it up into diazo-benzol-sulphonic acid and 
 2, 4-dinitro-dimethyl-aniline (B. 38, 3206 ; 41, 1989). 
 
 [4']-Phenyl-amido-azo-benzol-[4]-sulphonie acid SO 3 H[4]C 6 H 4 [i]N= 
 N[i]C 6 H 4 [4']NHC 6 H 5 . Its sodium salt dyes wool and silk a beautiful 
 orange, and as a dye is known by the names tropceolin OO, orange IV. 
 It is used as an indicator in alkalimetry (B. 16, 1989). By reduction it 
 yields sulphanilic acid and p-amido-diphenyl-amine. 
 
 [4'] -Phenyl-amido-azo-benzol- [3] -sulphonic acid is formed from 
 metanilic acid, and bears the name metanil yellow. 
 
 Phenyl-hydrazin-sulphonie acids are produced upon reducing the 
 diazides of aniline-sulphonic acids with sodium sulphite or stannous 
 chloride (B. 22, R. 216), and by the direct action of concentrated 
 sulphuric acid upon phenyl-hydrazins (B. 18, 3172). 
 
 Phenyl-hydrazin-p-sulphonie acid C 6 H 4 .(NH.NH 2 )SO 3 H is not 
 readily soluble in water. It is used in the preparation of tartrazin 
 (Vol. I.), having the following constitution : 
 
 N NHC 6 H 4 SO 3 Na 
 II 
 COoNaC C CO 
 
 II I 
 
 N NC 6 H 4 SO 3 Na. 
 
 Hydrazo-benzol-m-disulphonic acid SO 3 H[3]C 6 H 4 [i]NH NH[i] 
 C 6 H 4 [3']SO 3 H has been prepared by the reduction of m-nitro-benzol- 
 sulphonic acid, and is converted into benzidin-disulphonic acid by 
 hydrochloric acid (B. 21, R. 323 ; 23, 1053). 
 
 Sulphinic Acids. Formation : (i) By the action of zinc dust upon 
 the ethereal solution of the sulphonic-acid chlorides. (2) From the 
 latter and thio-phenol salts : 
 
 C 6 H 5 S0 2 Cl+2C 6 H 5 SNa^C 6 H 5 S0 2 Na+NaCl+(C 6 H 6 S) 2 . 
 
i8o ORGANIC CHEMISTRY 
 
 (3) By a straightforward reaction, sulphinic acids are produced by the 
 action of Cu powder upon diazonium-salt solutions saturated with SO 2 
 (B. 32, 1136) : 
 
 C 6 H 5 N 2 .SO 4 H+SO 2 +Cu=C 6 H 5 .SO 2 H+N 2 +SO 4 Cu. 
 
 (4) Sulphinic acids are also produced from SO 2 and benzene in the 
 presence of Al chloride, a reaction in which the compound C1SO 2 A1C1 2 
 is formed as an intermediate product. The reaction is an extremely 
 smooth one (B. 41, 3315). In this case the phenol ethers yield also 
 sulphoxides and sulphonium bases (C. 1908, II. 237). (5) By the 
 action of SO 2 , or SO 2 C1 2 , upon phenyl-magnesium bromide (B. 37, 
 2153 ; C. 1905, I. 1145). (6) From sulphones with sodium (B. 26, 
 2813). (7) By the action of KCN or sodium arsenate upon benzol 
 thio-sulphonates (B. 41, 3351). (8) By decomposition of benzol- 
 sulphydroxamic acids. 
 
 Behaviour. The sulphinic acids are not very stable, and when 
 heated with water split up into sulphonic acids and disulphoxides. 
 
 The air and oxidising agents (especially MnO 4 K or BaO 2 ) convert 
 them into sulphonic acids. By reduction, zinc dust, and sulphuric acid, 
 the sulphinic acids are converted into thio-phenols. 
 
 Their salts unite with sulphur, forming thio-sulphonates. When 
 fused with alkalies they decompose into benzenes and alkaline sulphites. 
 By the action of thionyl chloride they yield sulphinic chlorides (B. 41, 
 4114), and with acetic anhydride, sulphinic anhydride (B. 41, 3323). 
 With aldehydes the sulphinic acids combine to form oxy-sulphones 
 CH 3 CH(OH)S0 2 C 6 H 5 ; to ajS-unsaturated aldehydes, ketones, and 
 carboxylic acids they add themselves like sulphurous acid with forma- 
 tion of sulphones, like C 6 H 5 CH(SO 2 C 6 H 5 )CH 2 COOH (C. 1904, I. 874). 
 
 Benzol-sulphinic acid and quinone unite to unsym. p-dioxy-diphenyl- 
 sulphone (H0) 2 [2, 5]C 6 H 3 [i]SO 2 C 6 H 5 (B. 27, 3259) ; this also reacts with 
 a number of other substances containing quinoid linkages (cp. B. 29, 
 2019). Benzol-sulphinic acid also reacts with o- and p-dioxy-benzols, 
 forming dioxy-diphenyl-sulphones, while phenol gives compounds like 
 oxy-diphenyl sulphide HOC 6 H 4 SC 6 H 5 , and aniline chlorohydrate yields 
 amido-diphenyl sulphide H 2 NC 6 H 4 SC 6 H5 (B. 36, 107). 
 
 The alkaline sulphinates form, with iodo-alkylene, mixed sulphones, 
 and with chloro-carbonic esters they form the real sulphinic esters 
 (B. 26, 308, 430) : 
 
 C 6 H 5 SO 2 Na+ClCO 2 C 2 H 5 == C 6 H 5 SOO.C 2 H 5 +NaCl+CO 2 . 
 
 With ferric chloride the sulphinic acids, in acid solution, form 
 slightly soluble ferric salts, well adapted to the isolation of the sulphinic 
 acids (C. 1909, I. 1649). 
 
 Benzol-sulphinic acid C 6 H 5 .SO.OH, m.p. 83. Zinc salt (C 6 H 5 SO 2 ) 2 
 Zn+2H 2 O. Ethyl ester, sp. gr. 1-141 (20), decomposes when it is 
 heated. 
 
 Benzol-sulphinic anhydride (C 6 H 5 SO 2 ) 2 O, m.p. 67, deliquesces 
 rapidly with formation of benzol-sulphonic acid and benzol-thio- 
 sulphonic phenyl ester C 6 H 5 SO 2 SC 6 H 5 . 
 
 Benzol-sulphinic chloride C 6 H 3 SOC1, colourless plates, m.p. 38, 
 fumes in air, and is rapidly decomposed by water, with regeneration 
 of benzol-sulphinic acid. 
 
ESTERS OF THE THIO-SULPHONIC ACIDS 181 
 
 o- and p-Toluol-sulphinie acid C 6 H 4 [i](CH 3 )[2]SOOH, m.p. 80 
 and 85 (/. pr. Ch. 54, 517 ; 56, 213). For further homologues, see 
 B. 32, 1140. Dimethyl- and diethyl-aniline-sulphinic acid R 2 NC 6 H 4 
 SO 2 H is formed by the action of thionyl chloride upon dimethyl- and 
 diethyl-aniline (A. 310, 137). Benzol-disulphinic acid C 6 H 4 (SO 2 H) 2 , 
 see B. 35, 2168 ; 36, 189. 
 
 Benzol-seleninie acid C ? H 5 SeOOH, m.p. 124, by oxidation of 
 phenyl diselenide with nitric acid, and by the action of HC1 upon 
 benzol-seleno-acid. On heating to 130 it passes into benzol-seleninic 
 anhydride (C 6 H 5 SeO) 2 O, m.p. 164 (C. 1909, II. 21). 
 
 Benzol- thio-sulphonic acid. Its salts result from the chloride of 
 benzol-sulphonic acid, and alkali sulphides, as well as from the inter- 
 action of benzol sulphinates and sulphur (B. 25, 1477). With organic 
 bases the thio-sulphonic acids often form easily crystallised salts 
 (C. 1900, I. 611). 
 
 DlSULPHOXIDES OR ESTERS OF THE THIO-SULPHONIC ACIDS. Alkyl 
 
 esters and alkylene esters of benzol-thio-sulphonic acid result from the 
 interaction of the potassium salt with the corresponding bromides 
 (B. 25, 1477). Phenyl-thio-sulphonic aceto-acetic ester C 6 H 5 SO 2 S. 
 CH(COCH 3 )COOC 2 H 5 , m.p. 56, from chloraceto-acetic ester and 
 potassium-benzol thio-sulphonate (C. 1900, II. 178). 
 
 Phenyl esters e.g. C6H 5 .SO 2 .S.CgH 5 are obtained (i) by oxi- 
 dising the thio-phenols with nitric acid ; (2) by heating the sulphinic 
 acids with water to 130 ; (3) by oxidation of disulphides with hydrogen 
 peroxide (B. 41, 2838). 
 
 Benzol disulphoxide C 6 H 5 .SO 2 .S.C 6 H 5 , m.p. 45, is insoluble in 
 water, but dissolves readily in alcohol and ether (B. 20, 2090). 
 
 Sulpho-benzol sulphide (C 6 H 5 SO 2 ) 2 S, m.p. 133, and sulpho-benzol 
 disulphide (C 6 H 5 SO 2 ) 2 S 2 , m.p. 76, trisulphide, m.p. 103, result from 
 the action of iodine and of chlorine upon potassium-benzol thio- 
 sulphonate ; also from benzol sulphinates and benzol thio-sulphinates 
 with sulphur chlorides (B. 24, 1141 ; /. pr. Ch. 2, 60, 113). 
 
 Disulphones, like diphenyl-sulphone C 6 H 5 SO 2 .SO 2 C 6 H 5 , m.p. 194, 
 phenyl-tolyl-disulphone C 6 H 5 SO 2 .SO 2 C 6 H 4 .CH 3 , m.p. 166, Ditolyl-di- 
 sulphone CH 3 C 6 H 4 SO 2 .SO 2 C 6 H 4 CH 3 , m.p. 212 with decomposition, are 
 formed by transposition of sulphinates with sulpho-chlorides (C. 1899, 
 II. 719). Also in small quantities, besides sulpho-acids, during the 
 oxidation of benzol-sulphinic acids with MnO 4 K (C. 1908, II. 1427). 
 On heating with alkalies they decompose into a mixture of sulphinates 
 and sulphonates. 
 
 Sulphoxides. Mixed aromatic-aliphatic sulphoxides are formed from 
 the aryl-alkyl sulphides by oxidation with H 2 O 2 (B. 41, 2836 ; C. 1909, 
 I- 35) > or from their dibromo addition products by the action of water. 
 
 Phenyl-sulphoxy-acetie acid C 6 H 5 SOCH 2 COOH, m.p. 116, is split 
 up by heating with mineral acids into thio-phenol and glycolic acid. 
 
 Diphenyl-sulphoxide, thionyl-benzol (C 6 H 5 ) 2 SO, m.p. 70, is pro- 
 duced (i) by the action of SO 2 or SOC1 2 upon benzenes in the presence 
 of A1 2 C1 3 (B. 20, 195 ; 27, 2547) '> ( 2 ) ^Y oxidation of diphenyl sulphide 
 with H 2 O 2 (B. 43, 289) ; (3) by the action of thionyl chloride or 
 diethyl sulphite upon phenyl-magnesium bromide (B. 43, 1135). 
 Potassium permanganate oxidises it to diphenyl-sulphone. 
 
 Diphenyl-selenium oxide (C 6 H 5 ) 2 SeO has been prepared by oxi- 
 
182 ORGANIC CHEMISTRY 
 
 dising diphenyl selenide (q.v.), or from the dibromide of the latter 
 (B. 29, 424). 
 
 SULPHONES. The alkyl-aryl sulphones are isomeric with the esters 
 of the alkyl-sulphonic acids. They result from the sodium sulphinates 
 and the alkylogens. The purely aromatic sulphones are obtained (i) 
 by the action of SO 3 or chloro-sulphonic acid upon benzenes (together 
 with sulphonic acids), 2C 6 H 6 +SO 3 =(C 6 H5) 2 SO 2 +H 2 O ; (2) by the 
 distillation of sulphonic acids (together with hydrocarbons); (3) by 
 the oxidation of the phenyl sulphide ; (4) on heating benzol-sulphonic 
 acids with benzenes and P 2 O 5 ; (5) by the action of zinc dust, or 
 aluminium chloride, upon a mixture of a sulphonic chloride and a 
 benzene hydrocarbon : 
 
 C 6 H 5 S0 2 C1+C 6 H 6 CH 3 - > S 2 " - C 6 H 6 +CH 3 [i]C e H 4 [ 4 ]SO 2 Cl. 
 
 The same phenyl-p-tolyl-sulphone results from benzol-sulphonic acid 
 and toluol, as from p-toluol-sulphonic acid chloride and benzene, which 
 would prove that both groups are in union with siilphur, and that the latter 
 is sexivalent (B. 11, 2181). (6) Nitro-substituted sulphones are readily 
 formed from o- and p-chloro-nitro-benzols with sulphinates (B. 34, 
 1150). (7) Oxy- and amido-substituted sulphones result from the union 
 of sulphinic acids with quinone- and quinone-imine derivatives. 
 
 Phenyl-ethyl-sulphone C 6 H 5 SO 2 C 2 H 5 , m.p. 42 and b.p. above 300. 
 Phenyl-ethyl-sulphone alcohol C 6 H 5 .SO 2 .CH 2 .CH 2 OH, is a syrup 
 formed from ethylene chloro-hydrin and sodium-benzene sulphinate, 
 as well as by the action of concentrated sodium hydroxide upon 
 ethylene-diphenyl-disulphone C 6 H 5 SO 2 .CH 2 .CH 2 .SO 2 .C 6 H 5 , m.p. 180. 
 Phenyl-sulphone-ethyl alcohol upon oxidation yields phenyl-sulphone- 
 acetic acid C 6 H 5 SO 2 CH 2 .CO 2 H, m.p. 112 ; caustic potash resolves this 
 into CO 2 and phenyl-methyl-sulphone C 6 H 5 .SO 2 .CH 3 , m.p. 88. Phenyl- 
 sulphone acetamide C 6 H 5 SO 2 CH 2 CONH 2 , m.p. 156, from sodium- 
 benzol sulphinate and chloro-acetamide (C. 1905, I. 1134). Phenyl- 
 sulpho-aceto-nitrile C 6 H 5 SO 2 CH 2 CN, m.p. 114. 
 
 The hydrogen of the CH 2 group in the esters of phenyl-sulphone- 
 acetic acid is replaceable by sodium, but not by alkyls (B. 22, 1447 ; 
 23, 1647 ; /. pr. Ch. 2, 60, 96 ; C. 1905, II. 1784). 
 
 Phenyl-allyl-sulphone C 6 H 5 SO 2 .C 3 Hs is an oil (A. 283, 185). 
 
 The a- and j3-phenyl-sulphone-propionic acids, melting at 115 and 
 123 (B. 21, 89), as well as numerous other mixed fatty-aromatic 
 sulphones of the greatest variety, have also been prepared. 
 
 Diphenyl-sulphone (C 6 H 5 ) 2 SO 2 , benzol-sulphone, sulpho-benzide, melt- 
 ing at 128 and boiling at 276, is formed by the distillation of 
 benzol-sulphonic acid, and by the oxidation of the phenyl sulphide 
 (C 6 H 5 ) 2 S and diphenyl sulphoxide (see above) ; further, from benzol- 
 sulphonic chloride C 6 H 5 .SO 2 C1 and mercury-diphenyl, as well as from 
 benzol and benzol-sulphonic chloride or sulphuryl chloride with 
 aluminium chloride (B. 26, 2940). It is also obtained by the action 
 of fuming sulphuric acid or SO 3 upon benzene. It is converted into 
 benzol-sulphonic acid when digested with concentrated sulphuric acid. 
 When heated with PC1 5 , or in a current of chlorine gas, it is decomposed 
 into chloro-benzol and the chloride of benzol-sulphonic acid. 
 
 With sulphur or selenium it forms the diphenyl-sulphone : diphenyl 
 
PHENOLS 183 
 
 sulphide or diphenyl selenide (B. 27, 1761). Sodium converts it into 
 sodium-benzol sulphinate and diphenyl (B. 26, 2813). 0- and p-nitro- 
 diphenyl-sulphone NO 2 C 6 H 4 SO 2 C 6 H 5 m.p. 147 and 143 ; and 2, 4, 6- 
 trinitro-diphenyl-sulphone (NO 2 ) 3 C 6 H 2 SO 2 C 6 H 5 , m.p. 233, are formed 
 from o- and p-nitro-chloro-benzol or picryl chloride with sodium-benzol 
 sulphinate. Diphenyl-selenone (C 6 H 5 ) 2 SeO 2 , melting at 155 and 
 boiling at 271, results on oxidising diphenyl-selenium oxide with 
 potassium permanganate (B. 29, 424). On heating alone it deflagrates, 
 giving off its oxygen and forming a stable diphenyl selenide. 
 
 7. Phenols. 
 
 The phenols are derived from the aromatic hydrocarbons by the 
 replacement of hydrogen of the benzene residue by hydroxyl. The 
 phenols, like the alcohols, are distinguished as mono-, di-, and tri- 
 hydric, according to the number of hydroxyl groups which have entered. 
 All of the six hydrogen atoms in benzene can be replaced by hydroxyl 
 groups. The phenols correspond to the tertiary alcohols, as they yield 
 neither acids nor ketones upon oxidation. Their acid nature, dis- 
 tinguishing them from alcohols, is governed by the more negative 
 nature of the phenyl group, and is enhanced by the entrance of more 
 negative groups (see Picric acid ; C. 1903, 1. 326 ; II. 717). In contrast 
 to the phenols, the aromatic alcohols, which are their isomerides, and 
 have the hydrogen of the side-chains replaced by hydroxyl, approach 
 the aliphatic alcohols in their behaviour. 
 
 Various representatives of the phenols have been found in the 
 vegetable kingdom. 
 
 Some of them occur already formed as phenol-sulphonic acids in 
 the urine of mammalia. In the organism of the latter many organic 
 bodies are oxidised to phenols : benzene to phenol, bromo-benzol to 
 bromo-phenol, aniline to amido-phenol, phenol to hydroquinone. In the 
 decay of albumin the presence of phenols has also been established. 
 
 Phenols are produced in the dry distillation of wood, particularly 
 beech-wood, turf, bituminous coal (B. 26, R. 151), and anthracite coal. 
 To isolate the phenols from coal-tar, shake the latter with caustic alkali, 
 in which they are soluble. Acids liberate them from this solution, and 
 then they can be purified by fractional distillation. 
 
 MONOHYDRIC PHENOLS. In addition to the methods of formation 
 just given, the following are worthy of note : 
 
 (1) The decomposition of the diazo-derivatives, especially their 
 sulphates, with boiling water or copper sulphate solution. 
 
 (2) Fusion of the sulphonic acids with potassium or sodium hydrox- 
 ide. This reaction was discovered in 1867 by Kekule, Wiirtz, and 
 Dusart, independently of each other : 
 
 C 6 H 5 .S0 3 K+KOH ---- C 6 H 5 .OH+S0 3 K 2 . 
 
 In practice this method is used to obtain phenols from sulpho-acids, 
 the operation being carried out in iron vessels. 
 
 The experiment in the laboratory is executed in a silver or nickel 
 dish, the fusion supersaturated with sulphuric acid, and the phenol 
 extracted by shaking with ether. 
 
 In fusing sulphonic acids or phenols containing halogens, the latter 
 
184 ORGANIC CHEMISTRY 
 
 are also replaced with formation of polyhydric phenols. Occasionally 
 the sulpho-group splits off as sulphate and is replaced by hydrogen ; 
 thus, cresol-sulphonic acid yields cresol. 
 
 (3) The halogen benzene substitution products do not react with 
 alkalies ; but if nitro-groups are present at the same time, the halogens 
 are replaced even by digesting with aqueous alkalies this will occur 
 the more readily if the nitro-groups be multiplied. In this respect 
 they approach the acid chlorides : 
 
 C 6 H 2 (N0 2 ) 3 C1+H 2 = C 6 H 2 (N0 2 ) 3 OH+HC1 
 
 Picryl chloride Picric acid. 
 
 (4) The amido-group in the nitro-amido-derivatives can also be 
 replaced by hydroxyl on boiling with aqueous alkalies ; ortho- and 
 para-nitranilines C 6 H 4 (NO 2 ).NH 2 (not meta-), yield their corresponding 
 nitro-phenols. The ortho-dinitro-products react similarly. 
 
 (5) Small quantities of phenol can be obtained from benzene by the 
 action of ozone, hydrogen peroxide (palladium hydride and water), and 
 by shaking with sodium hydroxide and air (B. 14, 1144). By the 
 addition of oxygen to benzene through the instrumentality of alu- 
 minium chloride. 
 
 (6) By the breaking down of phenol-carboxylic acids, when their 
 salts are subjected to dry distillation with lime. 
 
 (7) The synthesis of the higher phenols by introduction of alkyls into 
 the benzene nucleus takes place readily on heating the phenols with 
 alcohols and ZnCl 2 to 200 (B. 14, 1842 ; 17, 669 ; 27, 1614 ; 28, 407) : 
 
 C 6 H 5 .OH+(CH 3 ) 2 CH.CH 2 .OH == (CH 3 ) 3 CH[ 4 ]C 6 H 4 [i]OH. 
 
 Alkyl ethers of the phenols are simultaneously produced ; methyl 
 alcohol yields only phenyl-methyl ether C 6 H 5 .O.CH 3 . Magnesium 
 chloride (B. 16, 792) and primary alkali sulphates (B. 16, 2541) possess 
 the same condensing power as ZnCl 2 . 
 
 (8) Phenols, under the influence of concentrated sulphuric acid, 
 take up unsaturated hydrocarbons e.g. iso-amylene and form alkyl 
 phenols (B. 25, 2649). 
 
 (9) The introduction of alkyl groups into the phenol nucleus by 
 means of the aluminium or ferric chloride reaction is not simple (cp. 
 B. 32, 2424) ; the phenol ethers are more suitable. On ethylation of 
 phenol by means of ether and aluminium chloride, see B. 32, 2391. 
 
 Behaviour : Replacement of the Hydrogen Atoms. (i) The character 
 of the phenols, recalling the acids, expresses itself in the ease with which 
 they form salts, particularly with the alkalies. The hydrogen of the 
 hydroxyl group is also readily replaced (2) by alcohol radicles and 
 (3) by ac id radicles. 
 
 (4) The presence of an hydroxyl group in the place of an aromatic 
 hydrogen atom renders more easy the substitution of other hydrogen 
 atoms by chlorine, bromine, and the nitro-group. 
 
 (5) The phenols unite with the diazo-compounds, forming azo- and 
 diazo-dyes : oxy-azo-derivatives. 
 
 (6) Colour Reactions of the Phenols. On adding phenols (mono- or 
 polyhydric) to a solution of KNO 2 (6 per cent.) in concentrated sulphuric 
 acid, intense colorations arise ; with common phenol we get first a 
 
PHENOLS 185 
 
 brown, then green, and finally a royal-blue colour (reaction of Lieber- 
 mann) (see B. 17, 1875). Dyes are produced in this manner ; their 
 character is as yet unexplained. They have been called dichrolns 
 (B. 21, 249). The phenols afford similar colours in the presence of 
 sulphuric acid, with diazo-compounds and nitroso-derivatives. Ferric 
 chloride imparts colour to the solutions of most phenols. Mercury 
 nitrate, containing nitrous acid, colours nearly all the phenols red 
 (reaction of Plugge) (B. 23, R. 202). 
 
 Replacement of the Hydroxyl Group. (7) When heated with zinc dust 
 the phenols are reduced to hydrocarbons. 
 
 (8) The oxygen of the simple phenols is not very easily replaced 
 by chlorine when phosphorus pentachloride acts upon them. Phenol 
 itself has given the body C 6 H 5 OPC1 4 . The pentachloride acts with 
 greater ease upon the nitro-phenols, forming nitro-chloro-benzols. 
 
 (9) Phosphorus sulphide converts the phenols into thio-phenols. 
 (loa) The anilines result on heating with zinc ammonium chloride. 
 (io&) In the alkyl ethers of the nitro-phenols (as with the acid 
 
 esters) we can replace the OH by NH 2 , on heating with alcoholic 
 ammonia. 
 
 (n) For the oxidation of the alkyl residues of homologous phenols, 
 see below. 
 
 Nuclear Syntheses. (i) Compare methods 7, 8, and 9, upon the 
 replacement of the aromatic hydrogen atoms of the phenols by alkyl 
 groups. 
 
 (2) The alkali salts of the phenols are converted by carbon dioxide, 
 at higher temperatures, into the alkali salts of oxy-acids phenol- 
 carboxylic acids (compare salicylic acid). 
 
 (3) The phenols also yield phenol-carboxylic acids with carbon tetra- 
 chloride and sodium hydroxide. 
 
 (4) Oxy-aldehydes or phenol-aldehydes (see salicyl-aldehyde) are 
 produced from phenols, chloroform, and caustic soda. 
 
 (5) The phenols condense with formaldehyde to phenol alcohols (see 
 Saligenin) . 
 
 (6) Cumarins (q.v.) are formed on heating phenols with malic acid 
 and sulphuric acid. 
 
 (7) Dye-stuffs belonging to the aurin series, and derived from tri- 
 phenyl-methane CH(C 6 H 5 ) 3 (q.v.), are obtained from the phenols by 
 their action upon benzo-trichloride C 6 H 5 .CC1 3 . 
 
 (8) The so-called phthalelns are combinations of phthalic acid 
 and o-sulpho-benzoic anhydride with the phenols. Similar reactions 
 occur with naphthalic anhydride (q.v.), succinic anhydride, and other 
 anhydrides of dibasic carboxylic acids. 
 
 Reduction of the Phenols. On conducting phenyl vapours mixed with 
 excess of hydrogen over finely divided nickel at 2i5-230, the phenols 
 are reduced to hexahydro-phenols (C. 1904, I. 279 ; see also B. 40, 
 1286). 
 
 By reduction of phenol with alternating currents, cyclo-hexanone is 
 produced (/. pr. Ch. 2, 38, 65). 
 
 Breaking down of the Benzene Nucleus of the Phenols. (i) By oxida- 
 tion of phenol (q.v.). (2) By treating the phenols with chlorine, and 
 then decomposing the chlorine addition products with alkalies. 
 
 BENZO-PHENOL, Phenol, carbolic acid, C 6 H 5 .OH, m.p. 43 anol b.p. 
 
i86 ORGANIC CHEMISTRY 
 
 183; its specific gravity is 1-084 ()- It is obtained from amido- 
 benzol, from benzol-sulphonic acid, from the three oxy-benzoic acids, 
 etc., by the methods previously described. It occurs already formed 
 in Castoreum and in the urine of the herbivorae. 
 
 Commercial phenol is a colourless, crystalline mass, which gradually 
 acquires a reddish colour on exposure to the air (B. 27, R. 790 ; C. 
 1909, II. 597). Pure phenol crystallises in long, colourless prisms. It 
 possesses a characteristic odour, burning taste, and poisonous and 
 antiseptic properties. It dissolves in 15 parts at 20, and very readily 
 in alcohol, ether, and glacial acetic acid. It is volatile with steam. 
 Ferric salts impart a violet colour to its neutral solutions. Bromine 
 water precipitates [2, 4, 6]-tribromo-phenol from even very dilute 
 solutions. On introducing phenol into the organism, it occurs in 
 the urine as phenol-glucuronic acid (Vol. I.) and as phenyl-sulphuric 
 acid. 
 
 Diphenols C 12 H 8 (OH) 2 , derivatives of diphenyl (q.v.), are produced 
 on fusing phenol with caustic potash. 
 
 Diphenylene oxide is produced when phenol is distilled over lead 
 oxide. Aurin results when it is heated with oxalic or formic acid and 
 dehydrating agents (q.v.). Potassium permanganate oxidises phenol 
 to inactive or meso-tartaric acid (Vol. I.). Mono-persulphonic acid 
 oxidises it to pyrocatechin and hydroquinone (/. pr. Ch. 2, 68, 486). 
 Chlorine finally changes phenol to keto-chlorides, which are derived 
 from di- and tetrahydro-benzol (B. 27, 537). Chlorine and caustic soda 
 convert phenol into trichloro-R-pentene-dioxy-carboxylic acid. The 
 most important reactions of phenol have been previously described. 
 
 History. -Runge discovered (1834) phenol in coal-tar and called it 
 carbon-oil acid, or carbolic acid. He also observed the physiological 
 properties it possessed in common with creosote. Laurent, in 1841, 
 first obtained it pure and gave it the names hydrate de phenyle or acide 
 phenigue, from (fraivew, to illuminate, probably because it occurs in the 
 tar produced in the manufacture of illuminating gas. Gerhardt, who 
 prepared it from salicylic acid, introduced the name phenol, indicating 
 thereby that it was an alcohol. In 1867 Lister, of Glasgow, showed its 
 great importance in surgery as a disinfectant. 
 
 Phenolates. Phenates, potassium phenate C 6 H 6 OK, and sodium 
 phenate C 6 H 5 ONa, are obtained by dissolving phenol in caustic potash 
 or soda, evaporating the solution, and sharply drying the residue. Both 
 salts dissolve readily in water (B. 26, R. 150). Carbon dioxide sets 
 phenol free from them ; it is, therefore, not soluble in the alkali 
 carbonates. 
 
 Calcium phenate (C 6 H 5 O) 2 Ca, and mercury phenate (C 6 H 5 O) 2 Hg. 
 (See B. 29, R. 178, for the compounds of the phenols with aluminium 
 chloride ; and see Salicylic acid for the action of CO 2 upon dry phenates.) 
 Aluminium phenate (C 6 H 5 O) 3 A1, by heating phenol with Al. It is a 
 glassy mass, melting about 265 (C. 1906, II. 114). On combinations 
 of phenols with Al chloride, see B. 29, R. 178 ; with nitrogen bases, 
 B. 35, 1207). 
 
 HOMOLOGOUS PHENOLS. It is strange that the cresols, as well as 
 other higher phenols, cannot be oxidised by the chromic acid mixture : 
 the OH-group prevents the oxidation of the alkyl groups by chromic 
 acid. If, however, the phenol-hydrogen is replaced by alkyls, or acid 
 
PHENOLS 187 
 
 radicles (in the phenol ethers and esters), then the oxidation of the 
 alkyl does take place with the production of ether acids or ester 
 acids. 
 
 The readily prepared sulphuric, or phosphoric, acid esters of the 
 homologous phenols are best adapted for oxidation with an alkaline 
 permanganate solution (B. 19, 3304), whereas the free phenols are 
 completely destroyed by this reagent (compare oxidation of phenol, 
 above) . 
 
 The oxidation of the alkyls in the sulpho-acids of the homologous 
 phenols is similarly influenced by the sulpho-group. In general, nega- 
 tive atoms, or groups, prevent the oxidation of alkyls in the ortho-position 
 by acid oxidants, whereas alkaline oxidants e.g. KMnO 4 do precisely 
 the reverse, in that they first oxidise the alkyl group holding the ortho- 
 position (A. 220, 16). The methyl groups of the methyl-phenols, such 
 as the cresols and xylenols, are converted by molten alkalies, with 
 the addition of PbO or PbO 2 (B. 39, 794), into carboxyl groups, 
 and there result oxy-benzoic acids, oxy-toluic acids, oxy-phthalic 
 acids, etc. (compare the like behaviour of the homologous pyrrols and 
 indols). 
 
 p-Alkylated halogen phenols are oxidised by nitric acid to so-called 
 quinitrols and quinols, which substances are dealt with in connection 
 with pseudo-phenol bromides and methylene-quinones in the chapter 
 on " Phenol Alcohols." 
 
 Other transposition reactions are given above. The liquid homo- 
 logous phenols are particularly characterised by the melting-points of 
 their benzoyl esters ; therefore these will be given in connection with 
 the various members. 
 
 1. Cresols, oxy-toluols, CH 3 .C 6 H 4 OH. The three isomerides occur 
 in coal-tar and beechwood tar. 
 
 They are obtained from the toluidins by method I., and from the 
 toluol-sulphonic acids by method II. They have a similar odour, but 
 it is more disagreeable than that of phenol. They are less poisonous, 
 and are disinfectants. They are changed to toluol when heated with 
 zinc dust. Sodium and carbon dioxide produce the corresponding 
 cresotinic acids. 
 
 See above for their behaviour towards molten caustic potash and 
 other oxidising agents. o-Cresol is obtained from carvacrol, and the 
 m-body from thymol (see below) . The latter is also prepared from the 
 dibromide of synthetic j8-methyl-keto-R-hexene (q.v.) by the elimina- 
 tion of hydrogen bromide (A. 281, 98). 
 
 o-Cresol, [i, 2\-oxy-toluol, m.p. 31, b.p. 188 
 m-Cresol, [i, 3}-oxy-toluol, ,, 4, 201 
 p-Cresol, [i, ^-oxy-toluol, 36, 198. 
 
 Ferric chloride colours o-cresol blue. The crude cresols are used 
 as disinfectants : creolin is a solution of the crude cresols in alkalies ; 
 cresolin is a solution of the same in resin soaps ; while lysol is a solution 
 of crude cresols in oline soaps. See B. 14, 687, for the behaviour of the 
 cresols in the animal organism. 
 
 2. Phenols C S H 9 OH. Oxy-dimethyl-benzols and oxy-ethyl-benzol. 
 The six possible xylenols C 6 H 3 (CH 3 ) 2 .OH have been prepared. 
 
i88 ORGANIC CHEMISTRY 
 
 Ethyl-phenols C 6 H 4 (C 2 H 5 ).OH. From the ethyl-benzol-sulphonic 
 acids (B. 27, R. 189). 
 
 o-Ethyl-phenol, liquid, b.p. 203 ; benzoyl compound, m.p. 39 
 m-Ethyl-phenol, 214; 52 
 
 p-Ethyl-phenol, m.p. 45, 215 ; 59. 
 
 3. Phenols C 9 H n .OH. Mesitol C 6 H 2 (CH 3 ) 3 .OH, from amido- 
 mesitylene and mesitylene-sulphonic acid, m.p. 68 and b.p. 220. 
 [i]OH[2,4,5]-Pseudo-cumenol C 6 H 2 (CH 3 ) 3 .OH, from pseudo-cumene- 
 sulphonic acid, m.p. 73 and b.p. 232 (B. 17, 2976). On the bromina- 
 tion products of pseudo-cumenol, and the formation of pseudo-phenol 
 bromides, insoluble in alkalies, see " Phenol Alcohols." 
 
 m-n-Propyl-phenol, from iso-safrol, m.p. 26 and b.p. 228 (B. 23, 
 1162). p-n-Propyl-phenol boils at 232. p-Iso-propyl-phenol melts at 
 61, and boils at 229. It is also produced along with hydroquinone 
 on decomposing diphenol-/?-propane (CH 3 ) 2 C(C 6 H 4 OH) 2 (from the 
 action of fuming hydrochloric acid on acetone and phenol), with 
 molten caustic potash (B. 25, R. 334). 
 
 4. Phenols C 10 H 13 .OH. There are twenty possible isomerides. 
 Thymol and carvacrol merit notice. They occur in vegetable oils. 
 Both are derivatives of ordinary p-cymol, and contain the iso-propyl 
 group. 
 
 Thymol, when heated with P 2 O 5 , breaks down into propylene and 
 m-cresol; while carvacrol, under similar treatment, yields propylene 
 and o-cresol. 
 
 Thymol = [3]-Methyl-[6]-iso-propyl-phenol C3H 7 [6]C 6 H 3 f^ 
 
 Carvacrol = [2] -Methyl- [5] -iso-propyl -phenol C3H 7 [5]C 6 H 3 < p 
 
 U[2]CH 3 
 
 Thymol, melting at 44 and boiling at 230, crystallises in large, 
 colourless plates. It exists with cymol C 10 Hj 4 , and thymol C 10 H 1? , 
 in oil of thyme (from Thymus vulgaris), and in the oils of Ptychotis 
 ajowan and Monarda punctata. To obtain the thymol, shake these oils 
 with potassium hydroxide, and from the filtered solution precipitate 
 thymol with hydrochloric acid. It is artificially prepared from nitro- 
 cumin-aldehyde (q.v.), as well as from dibromo-menthone, by the split- 
 ting-off of hydrogen bromide (B. 29, 420). It has a thyme-like odour 
 and answers as an antiseptic. 
 
 Ordinary cymol is obtained by distilling it with P 2 S 5 . Thymo- 
 quinone (q.v.) is produced in its oxidation. 
 
 Iodine and caustic potash convert thymol into di-iodo-di-thymol, 
 a diphenyl derivative which has been substituted for iodoform under 
 the names aristol and annidalin. 
 
 On the processes of iodination and bromination of thymol, see 
 C. 1903, I. 766. 
 
 Carvacrol, cymo-phenol, melting at o and boiling at 236, isomeric 
 with thymol, occurs already formed in the oil of certain varieties of 
 satureja, also in Briganum hirtum, and is obtained from an isomeric 
 carvol, a dihydro-cymol derivative (q.v.) contained in the oil of Carvum 
 carvi, and certain other oils, when it is heated with glacial phosphoric 
 acid (B. 19, 12). It is further prepared by heating camphor with 
 
PHENOLS 189 
 
 iodine (i part), using a return condenser. It is made artificially from 
 cymol-sulphonic acid (B. 11, 1060). 
 
 Distillation with P 2 S 5 converts carvacrol into cymol and thio- 
 carvacrol C 10 H 13 .SH. 
 
 s-Carvaerol (CH 3 )[3](CH 3 ) 2 CH[5]C 6 H 3 [i]OH melts at 54 and boils 
 at 241 (B. 27, 2347). Methyl-p-norm.-propyl-phenol (CH 3 )[2]C 3 H 7 
 [5]C 6 H 3 OH, from the corresponding sulpho-acid, boils at 240 (B. 29, 
 R. 417). 
 
 p-Tertiary butyl-phenol (CH 3 ) 3 C[4]C 6 H 4 [i]OH, melting at 98 and 
 boiling at 237, is obtained from isobutyl alcohol, phenol, and zinc 
 chloride (B. 24, 2974). Oxidised with MnO 4 K, it gives trimethyl-pyro- 
 racemic acid and trimethyl-acetic acid (A. 327, 201). 
 
 p-Tertiary amyl - phenol (CH 3 ) 2 (C 2 H 5 )C[4]C 6 H 4 [i]OH, melting at 
 93 and boiling at 266, results from the action of ZnCl 2 upon iso-amyl 
 alcohol or tertiary amyl alcohol, and from iso-amylene, phenol, acetic 
 acid, and sulphuric acid (B. 28, 407). Oxidised with MnO 4 K, it gives 
 dimethyl-ethyl-pyro-racemic acid and dimethyl-ethyl-acetic acid 
 (A. 327, 201). 
 
 Diethyl-phenols, tetra-ethyl-phenol (B. 22, 317 ; 32, 2392). 
 
 Tetramethyl-phenols (B. 15, 1852 ; 17, 1916 ; 18, 2842 ; 21, 645, 
 907). 
 
 Pentamethyl-phenol, m.p. 125, b.p. 267 (B. 18, 1826). 
 
 DERIVATIVES OF THE MONOHYDRIC PHENOLS. 
 
 The behaviour of the phenols was given under the example selected- 
 ordinary phenol. Because this can be obtained with comparative ease, 
 more derivatives of it, than of its homologues, have been prepared. 
 In the following pages the derivatives of the homologues will only be 
 brought forward and discussed in case they possess theoretical or 
 practical value, and then in connection with the compounds of the 
 corresponding phenol. 
 
 Phenol-alcohol Ethers. (i) Like the ethers of the aliphatic alcohols, 
 they result from the interaction of alkyl iodides and phenates. The 
 phenol is digested with caustic potash, and the alkyl iodide, or methyl 
 chloride, is conducted over sodium phenate heated to 200 (B. 16, 
 
 2513). 
 
 (2) By heating a mixture of the alkali salts of the phenols with an 
 excess of alkyl sulphates, in aqueous or alcoholic solution (B. 19, R. 139). 
 
 (3) Together with hydrocarbons on decomposing benzol-diazo- 
 compounds with alcohols (B. 25, 1973). 
 
 (4) By heating phenyl-carbonic alkyl ester with elimination of CO 2 : 
 
 C 6 H 5 OCOOCH 3 = C 6 H 5 OCH 3 +CO 2 
 (B. 42, 2237). 
 
 (5) The phenols are converted at ordinary temperatures by diazo- 
 methane, with evolution of nitrogen, into their methyl ethers (B. 28, 
 
 857) : 
 
 C 6 H 5 OH+CH 2 N 2 = C 6 H 5 OCH 3 +N 2 . 
 
 Dimethyl sulphate (CH 3 ) 2 SO 4 , p-toluol-sulphonic ester, and other 
 bodies have been recommended as practical alkylators for phenols 
 (A. 327, 120 ; B. 27, R. 955). 
 
igo ORGANIC CHEMISTRY 
 
 (6) By heating the phenol ethers of phenol-carboxylic acids with 
 lime or baryta : 
 
 C0 2 H[i]C 6 H 4 [ 4 ]OCH 3 ^~> C 6 H 6 OCH 3 
 Anisic acid Anisol. 
 
 Boiling with alkalies does not change the phenol ethers. Only 
 after long heating with alcoholic potash to a high temperature does 
 phenol form by disintegration (B. 34, 1812). The ethers of multi- 
 valent phenols are partly saponified ; veratrol produces guajacol (C. 
 1898, I. 456). Heating with HI, HBr, or HC1 breaks up most phenyl- 
 alkyl ethers into their generators : 
 
 C 6 H 5 OCH 3 -fHI = C 6 H 5 OH+CH 3 I. 
 
 This easy detachment of CH 3 I and C 2 H 5 I, on heating phenol ethers 
 with concentrated HI, may be used for the quantitative determination 
 of the number of methoxyl or ethoxyl groups in a compound, the iodine 
 compounds being converted into silver iodide in an alcoholic silver 
 nitrate solution, and weighed (Zeisel, M. 6, 989 ; 7, 406). The phenol 
 ethers are also decomposed by A1 2 C1 6 (B. 25, 3531) ; PC1 5 only chlorinates 
 the nucleus (B. 28, R. 612). With Cl, Br, I, HNO 3 , and H 2 SO 4 the 
 phenol ethers behave like aromatic hydrocarbons. 
 
 Anisol, methyl-phenyl ether C 6 H 5 .O.CH 3 , is produced by distilling 
 anisic or p-methyl-salicylic acid. It boils at 152 ; its specific gravity 
 at 15 is 0-991. It is not reduced by zinc dust (C. 1904, 1. 1005). 
 
 Phenetol, ethyl-phenyl ether (C 6 H 5 ).O.C 2 H 5 , b.p. 172, has the 
 specific gravity 0-9822(0). The iso-amyl ether boils at 225. 
 
 Bromethyl-phenyl ether BrCH 2 .CH 2 .O.C 6 H 5 melts at 39 (/. pr. Ch. 
 2, 24, 242). 
 
 Bromethenyl-pheny* ether BrCH : CHOC 6 H 5 , b.p. 16 166, from 
 acetylene dibromide with potassium phenol ; when treated with alcoholic 
 potash it gives phenoxy-aeetylene C 6 H 5 .OC=CH, b.p. 35 75, an easily 
 decomposed oil, which readily forms normal acetylene salts C 6 H 5 OC ; 
 CAg, (C 6 H 5 OCC) 2 Cu 2 , C 6 H 5 OCCNa. 
 
 Phenol-methylene ether CH 2 (OC 6 H 5 ) 2 , m.p. 81, b.p. 165 (B. 46, 
 2789). Phenol-ethylene ether, glyeol-diphenyl ether C 6 H 5 OCH 2 CH 2 
 OC 6 H 5 , m.p. 95, is isomeric with phenol-acetol (C 6 H 5 O) 2 CHCH 3 , m.p. 
 10, b.p. 175, obtained from potassium phenol, with aldehyde chloride 
 (C. 1900, 1. 813). Glycol-monophenyl ether, b.p. 80 165 (B. 29, R. 289). 
 Glycerine-monophenyl ether C 6 H 5 OCH 2 .CHOH.CH 2 9H, m.p. 70, 
 is formed by heating phenol with glycerine and sodium acetate (M. 
 
 /\ 
 29, 951), or by adding water to phenyl-glyeidie ether C 6 H 5 OCH 2 CH CH 2 , 
 
 b.p. 242, obtained besides glycerine-diphenyl ether, m.p. 82, by trans- 
 formation of sodium phenyl with epichloro-hydrin (C. 1908, I. 2032 ; 
 1910, I. 1134). 
 
 Phenoxalkylamines . ^-Phenoxethylamines NH 2 .CH 2 .CH 2 .O. C 6 H 5 , 
 b.p. 228 (B. 24, 189). y-Phenoxy-propylamine NH 2 .CH 2 .CH 2 . 
 CH 2 .O.C 6 H 5 , b.p. 241 (B. 24, 2637). S-Phenoxy-butylamine NH 2 CH 2 
 CH 2 CH 2 CH 2 OC 6 H 5 , b.p. 255 (B. 24, 3232). 
 
 Phenol ethers of aldehyde alcohols, ketone alcohols, and alcohol 
 acids have been obtained from the corresponding chlorinated alde- 
 hydes, ketones, and carboxylic acids, by the action of sodium phenate : 
 
PHENOLS 191 
 
 Phenoxy-acetaldehyde C 6 H 6 O.CH 2 .CHO, b.p. 119 (30 mm.) (B. 
 28, R. 295). 
 
 Phenoxy-aeetone, phenacetol C 6 H5O.CH 2 .CO.CH 3 , b.p. 230, is con- 
 densed by concentrated sulphuric acid to methyl cumarone (q.v.) (B. 28, 
 1253 ; 35, 3553). 
 
 Phenoxy-aeetie acid C 6 H 5 O.CH 2 .COOH, m.p. 96, is isomeric with 
 almond acid C 6 H 5 CH(OH).COOH. It results from monochloracetic 
 acid and potassium phenate at 150, as well as from the oxidation of 
 phenoxy-acetaldehyde. It is a strong antiseptic (B. 19, 1296 ; 27, 
 2796). 
 
 Phenoxy-acetyl chloride C 6 H 5 OCH 2 COC1, b.p.^ 169 (see B. 35, 
 356o). 
 
 Diphenoxy-aeetic acid (C 6 H 5 O) 2 CHCO 2 H, m.p. 91 (B. 27, 2796). 
 a- and y-Phenoxy-butyrie acid melt at 99 and 60 (B. 29, 1421). For 
 homologous a-phenoxy-aliphatic acids, see B. 33, 924, 1249. 
 
 a-Phenoxy-aceto-acetic ester CH 3 .CO.CH(OC 6 H 5 )CO 2 C 2 H 5 , from 
 sodium phenate and a-chloraceto-acetic ester, is a thick oil. Con- 
 centrated sulphuric acid condenses it to methyl-cumarilic ester. 
 Phenoxy-fumarie ester C 6 H 5 OC(COOR) : CHCO 2 R, from sodium 
 phenol and acetylene-dicarboxylic ester (C. 1900, II. 1210). 
 
 Phenol Ethers. Phenyl ether (C 6 H 5 ) 2 O, diphenyl oxide, melting 
 at 28 and boiling at 252, is produced by distilling copper benzoate 
 (together with benzoic phenyl ether) and digesting diazo-benzol sul- 
 phate with phenol (B. 25, 1973) ; also by heating phenol with zinc 
 chloride to 350, or, better, with aluminium chloride (B. 14, 189). It 
 crystallises in long needles, and possesses an odour resembling that of 
 geraniums. It dissolves readily in'alcohol and ether. It is not reduced 
 on heating with zinc dust or hydriodic acid. 
 
 Nitrated phenyl ethers have been obtained by the interaction of the 
 corresponding nitro-haloid benzols and the potassium salts of phenols : 
 o-Nitro-phenyl ether C 6 H 5 O.C 6 H 4 NO 2 boils at 235 (60 mm.), o, o'-Di- 
 nitro-phenol ether (NO 2 .C 6 H 4 ) 2 O melts at 114 (B. 29, 1880, 2084; 
 C. 1903, I. 634). 
 
 Acid Esters of Phenol. The acid esters are obtained by acting with 
 acid chlorides or anhydrides upon the phenols or their salts ; also by 
 digesting the phenols with acids and POC1 3 . To effect the substitu- 
 tion of all the hydroxyl-hydrogen atoms in the polyhydric phenols by 
 acetyl groups, it is recommended to heat them with acetic anhydride 
 and sodium acetate. On boiling with alkalies, or even with water, they, 
 like all esters, break down into their components. 
 
 Esters of Inorganic Acids. Phenyl-sulphonic ester is not known in 
 a free state. Its sodium salt NaSO 2 OC 6 H 5 results from the action of 
 SO 2 upon sodium phenate. Methyl iodide converts it into methyl-sul- 
 phonic phenyl ester CH 3 SO 2 OC 6 H 5 (cp. B. 25, 1875). Sulphonic aryl 
 ester salts are also formed from phenols with sodium disulphite ; they 
 are distinguished for their reacting power ; in some, the OSO 2 Na 
 group is replaced by NH 2 on heating with ammonia (C. 1901, II. 1136). 
 
 Phenyl-sulphurie acid C 6 H 5 .O.SO 3 H is not known in a free state ; 
 when liberated from its salts by concentrated hydrochloric acid, it im- 
 mediately breaks down into phenol and sulphuric acid. Its potassium 
 salt C 6 H 5 .O.SO 3 K forms flakes, not very soluble in cold water, and 
 occurs in the urine of herbivorous animals, and also in that of man and 
 
I 9 2 ORGANIC CHEMISTRY 
 
 the dog after the ingestion of phenol. It is synthetically prepared, like 
 other phenols, on heating potassium phenoxide with an aqueous solu- 
 tion of potassium pyro-surphate (B. 9, 1715) ; also from phenol and 
 chloro-sulphonic acid by means of pyridin in CS 2 solution, and subse- 
 quent treatment with KOH (C. 1901, I. 313). 
 
 The phenyl-sulphuric acids are very stable in aqueous and alkaline 
 solution ; upon digesting with mineral acids, however, they are very 
 rapidly decomposed. When potassium-phenyl sulphate is heated in 
 a tube, it passes quietly into potassium-p-phenol sulphonate. 
 
 Phenyl Esters of the Phosphoric Acids. These arise in the action 
 of PC1 3 and POC1 3 (A. 239, 310 ; 253, 120 ; B. 30, 2369) : 
 
 Phenyl-phosphorous chloride . . C 6 H 6 O.PC1 2 , boils at 90 (n mm.) 
 
 Diphenyl-phosphorous chloride . . (C 6 H 5 O) 2 PC1, 172 
 
 Triphenyl phosphite .... (C 6 H 5 O) 3 P, 220 
 
 Phenyl-phosphoric chloride . (C C H 5 O)POC1 2 , 121 
 
 Diphenyl-phosphoric chloride . . (C 6 H 5 O) 2 POC1, 195 (14 mm.) 
 
 Triphenyl phosphate, m. p. 45 . . (C 6 H 5 O) 3 PO, 245 (n mm.) 
 
 The last of these is best obtained by shaking up an alkaline phenol 
 solution with phosphorus oxy-chloride. 
 
 The two phenyl-phosphorous chlorides take up chlorine : 
 
 Phenyl-phosphoric tetrachloride . . C 6 H 5 OPC1 4 
 Diphenyl-phosphoric trichloride . . (C 6 H 6 O) 2 PC1 3 
 
 On phenol sulpho-phosphates, e.g. triphenyl sulpho-phosphate 
 (C 6 H 5 O) 3 PS, m.p. 53, see B. 31, 1094. 
 
 Phenyl Silicates (B. 18, 1679). 
 
 Phenyl Esters of Monocarboxylic Acids. Phenyl formate (/. pr. 
 Ch. 2, 31, 467). Phenyl-ortho-formic ester CH(O.C 6 H 5 ) 3 is formed by 
 boiling phenol with sodium hydroxide and chloroform. It melts at 71 
 and distils at 265, under 50 mm. pressure (B. 18, 2656). 
 
 Phenyl acetate CH 3 .COOC 6 H 5 boils at 195 (B. 18, 1716). Ortho- 
 acetic phenyl ester CH 3 C(OC 6 H 5 ) 3 melts at 98 (B. 24, 3678). 
 
 Phenyl Carbonates. The free phenyl-carbonic acid is not known. 
 The opposite is true of sodium-phenyl carbonate C 6 H 5 OCO 2 Na. It 
 is produced when CO 2 acts upon sodium phenoxide (under pressure). 
 It is a white hygroscopic powder, decomposed again by water. When 
 heated under pressure to I2o-i3o, sodium salicylate HOC 6 H 4 CO 2 Na 
 results, just as phenol-sulphonic acid is obtained from phenyl-sulphuric 
 acid (see above). Heated to I2O-I3O under pressure, it transposes 
 to sodium-phenol-o-carboxylie acid NaOC 6 H 4 COOH. When heated 
 to 190 with sodium phenate, sodium-phenyl carbonate yields disodium 
 salicylate and phenol (B. 38, 1375). 
 
 Phenyl Carbonate. The carbonic acid ester CO(O.C 6 H 5 ) 2 is pro- 
 duced on heating phenol and phosgene gas COC1 2 to 150. It is 
 readily obtained by leading phosgene gas into the aqueous solution of 
 sodium phenylate (/. pr. Ch. 17, 139 ; B. 17, 287). It crystallises from 
 alcohol in shining needles, and melts at 78. It yields sodium salicylate 
 when heated to 200 with sodium hydroxide. Urea results if it be 
 heated with ammonia (B. 23, 694). 
 
 Mixed carbonates containing phenol and alkyls e.g. phenyl-ethyl 
 carbonate CO 3 (C 2 H 5 )(C 6 H 5 ) are produced by the action of chloro- 
 
PHENOLS 193 
 
 formic esters upon the sodium salts of the phenols, or of alcohols upon 
 chloro-formic phenyl ester, obtained from phosgene with phenols (C. 
 1899, II. 825) ; they also form on heating phenyl carbonate with the 
 alcohols in the presence of urea (C. 1898, II. 476). On heating, they 
 split off CO 2 and pass into phenol-alkyl ether (B. 42, 2237). 
 
 Diphenyl-thio-carbonic ester C 6 H 5 OCSOC 6 H 5 (B. 27, 3410 ; C. 1906, 
 II. 1760). Phenyl-earbaminate, phenyl-urethane, NH 2 COOC 6 H 5 , melts 
 at 141 (B. 33, 51 ; A. 244, 43). Phenyl-earbamic phenyl ester C 6 H 5 
 NHCO 2 C 6 H 5 , from carbanile and phenol, m.p. 124 (B. 18, 875 ; 27, 
 1370). Diphenyl-thio-earbamic phenyl ester (C 6 H 5 ) 2 NCOOC 6 H 5 , m.p. 
 105, from diphenyl-urea chloride and phenol. Phenyl-carbaminic 
 phenyl ester C 6 H 5 O.CSNHC 6 H 5 , m.p. 148, is produced on heating 
 phenyl-mustard oil with phenol to 280 (B. 29, R. 177). 
 
 Phenyl-imido-carbonic phenyl ester C 6 H 5 N : C(OC 6 H 5 ) 2 , m.p. 136, 
 is obtained from iso-cyano-phenyl chloride and sodium phenate 
 (B. 28, 977). 
 
 Phenyl-allophanic ester co v^2Vr T is produced by conducting 
 
 \JN11. LxUo-^ails 
 
 cyanic acid vapours into anhydrous phenol. A crystalline mass. 
 
 Phenyl Esters of Dicarboxylic Acids. Phenyl - oxalic ester 
 (COOC 6 H 5 ) 2 , m.p. 136, b.p. 15 191 (B. 35, 3437). Malonic diphenyl 
 ester, m.p. 50 (B. 35, 3455). 
 
 Ethyl-phenyl-oxalic ester COOC 2 H 5 .COOC 6 H 5 , b.p. 236, is obtained 
 from ethyl-oxalic chloride (Vol. I.). The succinic ester melts at 118 
 and boils at 330. Phenyl-fumaric ester, m.p. 161, decomposes when 
 distilled slowly into CO 2 , phenyl-cinnamic ester (q.v.), and stilbene (q.v.) 
 (B. 18, 1948). 
 
 PHENOL SUBSTITUTION PRODUCTS. 
 
 Phenol Haloids. Formation: (i) Chlorine and bromine react 
 readily with phenols ; this is exemplified in bromine precipitating phenol 
 quantitatively from its aqueous solutions as [i OH,2, 4, 6]-tribromo- 
 phenol. Chlorine and bromine enter the ortho- and para-positions ; 
 there result at first the [i, 2]- and [i, 4] -mono-, then the [i, 2, 4-] 
 di-, and finally the [i, 2, 4, 6]-tri-substitution products. At I5o-i8o, 
 by action of chlorine or bromine vapours, abundant quantities of 
 o-chloro- and o-bromo-phenol (B. 27, R. 957) are produced. Sulphuryl 
 chloride, which easily chlorinates the free phenols (but not their 
 ethers), yields p-chloro-phenol (C. 1898, I. 1051). 
 
 The iodo-derivatives are formed by adding iodine and iodic acid to 
 a dilute potassium hydroxide solution of phenol (Kekule, A. 137, 161) : 
 
 5 C 6 H 5 OH+2l 2 +I0 3 H ---- 5 C 6 H 4 I.OH+ 3 H 2 0, 
 
 or by the action of iodine and mercuric oxide. Di-iodo-phenol is the 
 chief product in the latter case. 
 
 (2) In the phenol-sulphonic and phenol-carboxylic acids the action 
 of chlorine and bromine leads to the replacement of the sulpho- and 
 carboxyl groups in the o- and p-positions as phenyl hydroxyl by halogens 
 (B. 42, 4361). 
 
 (3) From substituted anilines, by the replacement of NH 2 by OH, 
 which may be brought about by the diazo-compounds ; this reaction 
 leads to pure mono-haloid phenols. (4) From the nitro-phenols by 
 
 VOL. II. O 
 
194 ' ORGANIC CHEMISTRY 
 
 replacing the nitro-group with halogens (effected through the amido- 
 and diazo-derivatives) . (5) By distilling substituted oxy-acids with 
 lime or baryta. 
 
 Behaviour. (i) The introduction of halogen atoms considerably 
 increases the acid character of phenol ; thus, trichloro-phenol readily 
 decomposes the alkaline carbonates. 
 
 (2) When fused with potassium hydroxide, the halogen is replaced 
 by the hydroxyl group. In this reaction it frequently happens, 
 especially at high temperatures, that not the corresponding isomerides, 
 but rather the more stable derivative, results ; for example, all the 
 bromo-phenols yield resorcin. The caustic potash fusion is, therefore, 
 not applicable in determining constitution. 
 
 (3) Sodium amalgam causes the replacement of the halogen atoms 
 by hydrogen. 
 
 (4) By the action of HNO 2 upon bromine-substituted phenols the 
 Br atoms, in o- or p-position to the hydroxyl, are easily replaced by 
 nitroyl (/. pr. Ch. 2, 61, 561 ; A. 333, 346). 
 
 Monohaloid Phenols. The monochloro-phenols in particular are 
 characterised by a disagreeable, very adherent odour. The bromo- 
 and iodo-phenols, being attacked at a lower temperature than the 
 chloro-derivatives, are changed, on fusing with potash, into the corre- 
 sponding dioxy-benzols. The higher the temperature rises in the 
 fusion of the o- and p-compounds, the greater will be the yield of 
 resorcin or m-dioxy-benzol ; the three isomeric monochloro-phenols 
 yield resorcin : 
 
 Ortho- Meta- Para- 
 
 M.p. B.p. M.p. B.p. M.p. B.p. 
 Chloro-phenol 7 176 28 212 41 217 
 
 Bromo-phenol liquid 195 32 236 66 238 
 
 lodo-phenol 43 .. 40 .. 94 .. (6.20,3019). 
 
 See B. 29, 997, 1409, 2595, for the iodo-anisols and phenetols. 
 
 Poly haloid Phenols. In the direct substitution the [2, 4]-di- and 
 [2, 4, 6]-trihaloids are produced quite readily. On prolonged chlorina- 
 tion of the phenols a tetrachloro-phenol is finally obtained (C. 1903, 
 I. 232). As to the iodination of phenol, see C. 1901, I. 1004 ; 1902, I. 
 638, 668. 
 
 [2, 4]-Dichloro-phenol, m.p. 43, b.p. 210 [2, 4, 6]-Trichloro phenol, m.p. 68, b.p. 244 
 
 [2, 5] -Dichloro -phenol, ,, 58, ,, 211 [2 4, 6]-Tribromo-phenol, ,, 92 
 
 [2, 4]-Dibromo-phenol ,, 40, ,, .. [2, 3, 5] -Tribromo -phenol, , 92, (B. 39, 4251) 
 
 [2, 4]-Di-iodo-phenol, ,, 72, ,, .. [2, 4, 6] -Tri-iodo -phenol, 
 
 [3, 5, 6]-Tri-iodo phenol, 
 
 [2, 3, 4, 6]-Tetrachloro-ph., m.p. 70 (B. 37, 4013). Pentachloro-ph., 
 [2, 3, 4, 6]-Tetrabromo-ph., 120 (A. 137, 209). Pentabromo-ph. 
 
 156 
 
 114 (C. 1904, I. 266) 
 
 186 (B. 28, R. 150) 
 
 225. 
 
 The silver salts of tribromo-phenol, as well as of some other poly- 
 brominated phenols, exist in an unstable orange-red, and a stable 
 white, modification. The cause of this allotropy is still unexplained 
 (B. 40, 4875). 
 
 The tri-, tetra-, and pentachloro- and bromo-phenols take up 
 chlorine and bromine, becoming chlorinated and brominated oxodi- 
 and oxotetra-hydra-benzols, from which the halogen phenols are regen- 
 erated by reduction (B. 37, 4010). On further bromination tribromo- 
 phenol gives bromine tribromo-phenol C 6 H 2 Br 4 O, m.p. 148 (A. 302, 
 
NITRO-PHENOLS 195 
 
 133 ; C. 1902, II. 358), which is easily reconverted into tribromo- 
 phenol, but is transposed into tetrabromo-phenol C 6 Br 4 H(OH) by 
 concentrated SO 4 H 2 , and yields dibromo-quinone on digesting with 
 lead acetate ; it must therefore be regarded as p-keto-dihydro-tetra- 
 bromo-benzol (B. 33, 675 ; C. 1902, I. 469) : 
 
 Br H Br H Br H 
 
 B7H Br > BTH Br2 - " BFH a 
 
 HNO 3 oxidises trichloro-phenol into dichloro-quinone (C. 1908, 
 I. 1776). 
 
 NITRO-PHENOLS. 
 
 The phenols, like the anilines, are very readily nitrated. The 
 entrance of the nitro-groups increases their acid character very con- 
 siderably. All nitro-phenols decompose alkaline carbonates (but see 
 C. 1898, II. 596). 
 
 Trinitro-phenol is a perfect acid in its behaviour ; its chloro- 
 anhydride C 6 H 2 (NO 2 ) 3 C1 reacts quite readily with water, re-forming 
 trinitro-phenol. The benzene nucleus of the nitro-phenols is capable 
 of ready substitution with the halogens ; whereas the nitro-hydro- 
 carbons are chlorinated with difficulty. 
 
 The nitro-groups replace the o- and p-hydrogen atoms referred to 
 hydroxyl, and with reference to one another, in the m-position : 
 
 C,H 5 OH 
 
 f[i]OH 
 
 r )[2]N0 2 
 
 2 |[4]N0 2 
 l[6]N0 2 
 
 While the colourless or faint-yellow free nitro-phenols are un- 
 doubtedly true phenols, the intensely red or yellow salts of the nitro- 
 phenols, as in the aliphatic nitro-compounds, are probably derivable 
 from a hypothetical nitrous acid of the structure O=C 6 H 4 =N^ 
 
 which is designated as an aci-nitro-phenol form (B. 39, 1084). Con- 
 siderable support is given to this view by the observation that the 
 ethers of the nitro-phenols exist in two isomeric series (B. 39, 1073). 
 Besides the colourless normal nitro-phenol ethers, the halogen alkyls, 
 acting upon the silver salts of the nitro-phenols, produce very unstable 
 ethers of a deep-red colour. These pass spontaneously into the 
 colourless isomeric ethers, and are quickly saponified with water alone, 
 with regeneration of the nitro-phenols. These unstable ethers corre- 
 spond to the strongly coloured nitro-phenol salts, and probably also 
 
 possess a quinoid structure: O=C 6 H 4 =N^ __ . Of the m-nitro- 
 
 \UCJti 3 
 
 phenols only the normal, colourless ethers have hitherto been obtained, 
 and this corresponds to the absence of m-quinones. 
 
 Mononitro-phenols NO 2 .C 6 H 4 .OH. Dilute nitric acid converts 
 phenol into o- and p- mononitro-phenol (in the cold it is chiefly the 
 p-compound which is formed). At 67, with the use of the electric 
 spark, there is five times as much of the p-body as at 40 (B. 26, 
 R. 362). 
 
196 ORGANIC CHEMISTRY 
 
 The o and p-compounds are separated by distillation with steam, 
 in which the p-compound is not volatile. Phenol in presence of 
 sulphuric acid is also nitrated by nitrogen dioxide (B. 24, R. 722). 
 o-Nitro-phenol is also obtained, together with a little of the para- 
 body, from nitro-benzol on heating with dry potash ; or from the 
 product of metallic sodium and nitro-benzol under a current of air. 
 
 o- and p-Nitro-phenols are also obtained by heating the correspond- 
 ing chloro- and bromo-nitro-benzols with caustic potash to 120, 
 whereas m-bromo-nitro-benzol does not react under similar circum- 
 stances. Ortho- and para-nitro-phenols are likewise produced from 
 the corresponding nitranilines by heating with alkalies. m-Nitro- 
 phenol is formed from m-nitraniline (from ordinary dinitro-benzol) by 
 boiling the diazo-compound with dilute sulphuric acid. p-Nitro-phenol 
 has also been obtained synthetically from nitro-malonic aldehyde with 
 acetone. 
 
 It is obtained from p-nitroso-phenol by oxidation with nitric acid 
 (C. 1903, I. 144). o-Nitro-phenol is formed, besides polynitro-phenols, 
 on the nitrogenation of benzene in the presence of mercury nitrate : 
 
 o-Nitro-phenol, m.p. 45, b.p. 214; methyl ether, m.p.-f 9, b.p. 265 
 m-Nitro-phenol, 96, .'. methyl ether, 38, 254 
 p-Nitro-phenol, ,, 114, . . methyl ether, ,, 48, 260. 
 
 o- and m-Nitro-phenols form yellow crystals ; the latter is rather 
 soluble in water. The o-body has a peculiar odour and sweet taste. 
 Its sodium salt forms dark-red prisms. 
 
 p-Nitro-phenol crystallises from hot water in long, colourless needles. 
 The potassium salt crystallises in yellow needles with two molecules 
 of water. 
 
 With HgO or mercuric nitrate the nitre-phenols yield, in the first 
 instance, the mercury salts of the phenols, (NO 2 C 6 H 4 O) 2 Hg, which 
 pass into mercuri-nitro-phenols, the Hg wandering to the nucleus. 
 These easily form the intensely coloured mercuric anhydrides, probably 
 
 derivable from the formula O : C 6 H 3 ^^>o (B. 39, 1105). By bromi- 
 
 nation, the p-nitro-phenol passes into [i, OH, 2, 6, 4]-dibromo-p-nitro- 
 phenol, m.p. 141 ; [4, 6]-dibromo-2-nitro-phenol, m.p. 117, is formed 
 from 2, 4, 6-tribromo-phenol with ethyl nitrite in alcoholic solution. 
 
 Dinitro-phenols (NO 2 ) 2 C 6 H 3 OH. a- or [i OH, 2, 4]-Dinitro-phenol, 
 melting at 114, and jS- or [i OH, 2, 6]-dinitro-phenol, melting at 64, 
 are produced in the nitration of phenol and of o-nitro-phenol. The 
 a-compound can also be obtained from p-nitro-phenol, as well as 
 from m-dinitro-benzol, by means of alkaline potassium ferricyanide. 
 The a-methyl ether melts at 86. It is transformed into [i NH 2 , 2, 4]- 
 dinitraniline by heating with ammonia. 
 
 The nitration of [i, 3]-nitro-phenol produces three isomeric dinitro- 
 phenols, melting at 104, 134, and 141. Further nitration produces 
 trinitro-phenols and trinitro-resorcin, 
 
 Sym. dinitro-phenelol C 6 H 5 O[i]C 6 H 4 [3, 5](NO 2 ) 2 , m.p. 96, is 
 obtained by the action of sodium ethylate upon trinifro-benzol (C. 1906, 
 I- 833). 
 
 Trinitro-phenols. Picric acid C 6 H 2 (NO 2 ) 3 .OH, melting at 122, 
 is obtained by the nitration of phenol, of [i, 2]- and [i, 4]-nitro-phenol, 
 
NITRO- PHENOLS 197 
 
 and of the two dinitro-phenols ; also, by the oxidation of sym- 
 metrical trinitro-benzol with potassium ferricyanide. It is therefore 
 [i OH, 2, 4, 6]-trinitro-phenol. 
 
 Picric acid is produced in the action of concentrated nitric acid 
 upon various organic substances, like indigo, aniline, resins, silk, 
 leather, and wool. 
 
 History. Woulfe found, in 1711, that nitric acid acting on indigo 
 produced a liquid which coloured silk yellow. Welter, in 1799, first 
 prepared pure picric acid by nitrating silk. It was called Welter's 
 bitter. Liebig called it carbon-nitric acid, carbazotic acid. Dumas 
 analysed it and called it picric acid, from TTIK/OO'S, bitter. Laurent, in 
 1842, discovered it to be a derivative of phenol. 
 
 Properties. Picric acid crystallises from hot water and alcohol, in 
 yellow flakes or prisms which possess a very bitter taste. It dissolves 
 in 160 parts of cold water, and rather readily in hot water. Its solution 
 imparts a beautiful yellow colour to silk and wool. It sublimes un- 
 decomposed when carefully heated. 
 
 Behaviour. With many hydrocarbons, like benzene, naphthalene, 
 and anthracene, picric acid forms beautiful crystalline derivatives, well 
 adapted for the recognition and separation of the higher aromatic 
 hydrocarbons. 
 
 The action of PC1 5 upon picric acid produces picryl chloride. On 
 heating barium picrate in an aqueous solution of bleaching lime, chloro- 
 picrin is formed (Vol. I.). 
 
 Prussic acid is produced on boiling a solution of barium picrate with 
 baryta water. Picric acid is converted by potassium cyanide into the 
 potassium salt of isopurpuric or picro-cyaminic acid C 8 H 4 N 5 O 6 K. It 
 crystallises in brown flakes with green-gold lustre, and formerly appeared 
 in commerce under the name Grenat soluble. It is no longer used. 
 Isopurpuric acid, liberated from its potassium salt by phosphoric acid, 
 and of a deep-violet colour, possesses, according to its decomposition 
 products, the constitution C 6 [2, 6](CN) 2 [i, 3](NO 2 ) 2 [4, 5](OH)(NHOH). 
 A behaviour towards KCN resembling that of picric acid is also shown 
 by o, p- and o, o-dinitro-phenols and other polynitro-phenol derivatives 
 (B. 37, 1843, 4388 ; 38, 3538, 3938)- 
 
 Salts and Ethers. The potassium salt, C 6 H 2 (NO 2 ) 3 .OK, crystallises 
 in yellow needles, soluble in 260 parts of water at 15. The sodium 
 salt is soluble in 10 parts water at 15, and is separated from its solution 
 by sodium carbonate. The ammonium salt consists of beautiful large 
 needles, and is applied in explosive mixtures. All the picrates 
 explode very violently when heated or struck. 
 
 The methyl ether of picric acid is produced in the nitration of anisol. 
 It melts at 65. The ethyl ether melts at 78. 
 
 jS-Trinitro-phenol, melting at 96, and y-trinitro-phenol, m.p. 117, 
 have been obtained from the dinitro-phenols resulting from the nitra- 
 tion of m-nitro-phenol. 
 
 Tetranitro-phenol, m.p. 130, consists of golden-yellow needles. It 
 is produced in the oxidation of diquinoyl-trioxime (q.v.). It is very 
 explosive (B. 30, 184). 
 
 Tetranitro-anisol, m.p. 154 (C. 1904, II. 205). 
 
 Nitro-cresols. o-Nitro-p-eresol NO 2 [2]CH 3 [4]C 6 H 3 OH, m.p. 77, 
 and p-nitro-o-cresol, m.p. 118, are prepared pure from the corre- 
 
ig8 ORGANIC CHEMISTRY 
 
 spending nitro-toluidins. The former is also easily obtained by nitro- 
 genation of p-cresol carbonate, and saponification of the resultant 
 compound (C. 1909, I. 965). By the action of fuming sulphuric acid it 
 is split up with formation of acetyl-acrylic acid (B. 42, 577). By 
 further nitrogenation of the methyl ethers of o-nitro-p-cresol and 
 p-nitro-o-cresol we obtain o-dinitro-compounds (B. 34, 2238). Nitro- 
 genation of o- and p-cresol easily yields dinitro-derivatives (B. 15, 1858). 
 Of these, the [2, 6]-dinitro-p-eresol, m.p. 84, has been used as an orange 
 dye in the form of its sodium salt, called Victoria orange, or saffron 
 substitute. Dinitro-o-cresol is used as an insecticide in the form of 
 salt-solutions, more especially against caterpillars, under the name of 
 Antinonnin (B. 27, R. 316). Nitrogenation of m-cresol yields a 
 trinitro-cresol (NO 2 ) 3 C 6 H(CH 3 )OH, m.p. 106, also formed from nitro- 
 coccus acid, and by nitrating thymol (C. 1901, II. 411). Tetranitro-m- 
 cresol, m.p. 175 (C. 1908, I. 724). Nitro-xylenols, see B. 42, 2917 ; 
 C. 1904, II. 1213. 
 
 Haloid Nitro-phenols. Numerous representatives of this class have 
 been obtained by the action of the halogens upon the nitro-phenols, 
 or by the nitration of the haloid phenols. 
 
 It is interesting to note that p-nitro-o-iodanisol C 6 H 3 [4]NO 2 [2]I 
 [i]OCH 3 has been prepared both in the nitration of o- as well as in 
 that of p-iodanisol. In the latter case, therefore, a migration, or 
 wandering, of the iodine atom in the nucleus has occurred (B. 29, 997) 
 
 NlTROSO-COMPOUNDS OF THE PHENOLS. 
 
 The nitroso-phenols are made : (i) by the action of nitrous acid 
 upon phenols (Baeyer, B. 7, 964), when the monohydric phenols yield 
 only mononitroso-compounds ; whereas dinitroso-derivatives are 
 obtained from the dihydric meta-dioxy-benzols, like resorcin. 
 
 (a) Nitrous acid, from alkali nitrite and dilute sulphuric acid or 
 acetic acid, is allowed to act upon the phenols (B. 7, 967 ; 8, 614) ; 
 (b) by means of the nitrites of heavy metals, which are decomposed 
 by the phenols themselves (B. 16, 3080) ; (c) from nitrosyl-sulphuric 
 acid HO.SO 2 .NO and phenols (A. 188, 353 ; B. 21, 429) ; (d) from 
 amyl nitrite and sodium phenolates (B. 17, 803). 
 
 (2) Upon boiling p-nitroso-alkylamines, like nitroso-dimethyl- 
 aniline (I. 163 ; II. 94) with alkalies : 
 
 NO[ 4 ]C 6 H 4 [i]N(CH 3 ) 2 +NaOH = NO[ 4 ]C 6 H 4 [i]OK+HN(CH 3 ) 2 . 
 
 (3) By the action of HC1 hydroxylamine upon quinones in aqueous 
 or alcoholic solution. Free hydroxylamine reduces the quinones to 
 hydroquinones (B. 17, 2061). This method favours the idea that the 
 nitroso-phenols are quinone-monoximes (Goldschmidt, B. 17, 801). 
 Hence, three constitutional formulas have been brought forward for 
 p-nitroso-phenol or quinone-monoxime (Quinones, q.v .) : 
 
 C 6 H 4 / OH and C 6 H 4 / or C 6 H 4 / 
 
 \NO \N.OH \N.OH 
 
 p-Nitroso-phenol Quinoxime. 
 
 o-Nitroso-phenol HO.C 6 H 4 [2]NO : as aniline is oxidised to nitroso- 
 benzol, so o-anisidin is oxidised by Caro's acid to o-nitroso-anisol 
 
NITROSO-COMPOUNDS OF THE PHENOLS 199 
 
 CH 3 OC 6 H 4 [2]MO, m.p. 103 ; on saponification with bisulphate, 
 this yields the o-nitroso-phenol, the Na salt of which forms deep-red 
 flakes (B. 35, 3036). 
 
 p-Nitroso-phenol, quinone-monoxime, crystallises from hot water in 
 colourless, delicate needles, which readily brown on exposure, and from 
 ether it separates in large greenish-brown flakes ; also by the action of 
 nitroso-benzol and NaHO (B. 33, 1954). It is soluble in water, alcohol, 
 and ether, and imparts to them a bright-green colour. When heated, it 
 melts with decomposition, and deflagrates at no-i2o. The sodium 
 salt crystallises in red needles, containing two molecules of water of 
 crystallisation. 
 
 The methods of producing nitroso-phenol from phenol with nitrous 
 acid, and from nitroso-dialkyl-anilines, argue for the nitroso-formula 
 of the nitroso-phenols ; as does their oxidation to p-nitro-phenol with 
 nitric acid or with an alkaline potassium ferricyanide solution. 
 
 The quinoxime formula is supported by their formation from quinone 
 with hydroxylamine hydrochloride, and the conversion into quino- 
 dioxime, as well as by the formation of hypochlorous esters 
 C 6 H 4 (O).NOC1 when acted upon by bleaching - lime (B. 19, 280). 
 Further, by the behaviour of the related nitroso-naphthols (q.v.), and 
 finally the feeble basic character of the nitroso-phenols (B. 18, 3198 ; 
 19, 280). Methylation of nitroso-phenol yields, not nitroso-anisol, 
 but quinone-methoxime O : C 6 H 4 : NOCH 3 , m.p. 83 ; p-nitroso-anisol 
 CH 3 OC 6 H 4 [4]NO, m.p. 23, from p-anisidin, by oxidation with mono- 
 persulphonic acid (Caro's acid), or from p-anisol-hydroxylamine with 
 ferric chloride (B. 37, 44). By dilute H 2 SO 4 it is easily saponified 
 into p-nitroso-phenol (B. 35, 3034). 
 
 Possibly the free nitroso-phenols have a quinone-oxime formula, 
 while the salts are derivable from the nitroso-phenol formula (cp. 
 B. 32, 3101). 
 
 The nitroso-phenols can be changed to nitroso-anilines. Hydro- 
 chloric acid converts nitroso-phenol into dichloramido-phenol. With 
 nitrous acid and with hydroxylamine it yields p-diazo-phenol : 
 
 HOC 6 H 4 NO ^?2 (HOC 6 H 4 N 2 OH) - -- O : C 6 H 4 : N 2 . 
 
 In a similar manner it forms azo-compounds with the amines. 
 Phenyl-hydrazin reduces it very readily to amido-phenol (B. 29, R. 294). 
 On adding a little concentrated sulphuric acid to a mixture of nitroso- 
 phenol and phenol, we obtain a dark-red coloration, which changes 
 to dark blue upon adding caustic potash. 
 
 Nitroso-m-cresol, m.p. 155 (B. 21, 729 ; C. 1900, I. 120). 
 
 Nitroso-o-eresol, from o-cresol and toluquinone (q.v.) (B. 21, 729), 
 m.p. 134. 
 
 Nitroso-thymol melts at 160 (B. 17, 2061 ; A. 310, 89). 
 
 AMIDO-PHENOLS. 
 
 These result from the reduction of nitro- and nitroso-phenols, or 
 the oxy-azo-compounds (B. 38, 2752). In the case of poly-nitrated 
 phenols, ammonium sulphide occasions but a partial reduction ; tin 
 and hydrochloric acid, however, effect a complete reduction of the 
 
200 ORGANIC CHEMISTRY 
 
 nitro-groups. For special methods of formation, see m- and p-amido- 
 phenol. 
 
 Behaviour. The free amido-phenols decompose quite easily, especi- 
 ally in moist air on exposure to light. 
 
 The amido-group considerably diminishes the acid character of the 
 phenols. This class of derivatives no longer forms salts with alkalies, 
 and only yields such compounds with the acids. 
 
 Like the o-phenylene-diamines, the o-amido-phenols form hetero- 
 cyclic derivatives with ease. These are anhydro-bases ; the benzox- 
 azoles, corresponding to the benzimide-azoles, are similar bodies obtained 
 from the o-amido-thio-phenols. 
 
 o-Amido-phenol NH 2 [2]C 6 H 4 [i]OH, m.p. 170, dissolves with diffi- 
 culty in water. o-Anisidin NH 2 [2]C 6 H 4 [i]OCH 3 , b.p. 218. 
 
 o-Imido-diphenyl oxide, phenoxazin o/^ 4 ^> NH wil1 be de - 
 
 H 
 6H4 6 
 
 scribed together with thio-diphenyl-amine, hydro-phenazin, and phena- 
 zin under the heterocyclic compounds (cp. also pyro-catechol) . 
 
 Methylation of the Amido-group of o-Amido-phenol (B. 23, 246). 
 When o-amido-phenol in methyl alcohol is treated with methyl iodide 
 and caustic potash, and later with hydrogen iodide, there results the 
 iodide of an ammonium base, which moist silver oxide changes to the 
 ammonium hydroxide. The latter loses water at 105, and changes 
 to a cyclic ammonium derivative similar to betai'n : o-trimethyl- 
 ammonium-phenol, which, heated to higher temperatures, rearranges 
 itself into o-dimethyl-anisidine. The hydrochloride of the ammonium 
 base breaks down upon distillation into methyl chloride and o-di- 
 methyl-amido-phenol, m.p. 45 : 
 
 /[i]N(CH 3 ) 3 Cl / [i]N(CH 3 ) 3 OH _ /[i]N(CH 3 ) 3 
 
 4 \[2]OH 4 \[2]OH 6 4 \[2]6 
 
 o-Trimethyl-ammonium- o-Trimethyl-ammonium- | o-Trimethyl-ammo- 
 chlorodi-phenol oxyd-hydrat-phenol | mum-phenol 
 
 [i]N(CH 3 ) 2 
 [2]OCH 3 
 o-Dimethyl-amido-phenol o-Dimethyl-anisidin. 
 
 o-Methyl-amido-phenol CH 3 NH[2]C 6 H 4 [i]OH, from o-methyl-anisi- 
 din C 6 H 4 (NHCH 3 )OCH 3 , with HC1. Its sulphate, mixed with hydro- 
 quinone, is sold as a photographic developer under the name " ortol " 
 (B. 32, 3514) ; see also Metol (C. 1903, I. 1129). 
 
 o-Oxethyl-anisidin HO.CH 2 CH 2 .NH[2]C 6 H 4 [i]OCH 3 , from o-anisi- 
 din and ethylene-chloro-hydrin, b.p. 305. 
 
 o-Formyl-amido-phenol CHO.NHC 6 H 4 OH, m.p. 129, from o-amido- 
 phenol with formic acid. Also, besides anthr anile, from o-amido- 
 benzaldehyde by oxidation with Caro's acid, probably by transposition 
 of o-hydroxylamine-benzaldehyde CHO.C 6 H 4 .NHOH. On heating 
 to i6o-i70 it passes into benzoxazol (B. 36, 2042). For acylated 
 o-amido-phenols, see C. 1907, I. 806. 
 
 o-Oxy-phenyl-urethane COOC 2 H 5 .NH[2]C 6 H 4 [i]OH, m.p. 86, is 
 formed by the reduction of o-nitro-phenyl-ethyl carbonate by trans- 
 position of the first product, viz. o-amido-phenyl-ethyl carbonate 
 NH 2 [2]C 6 H 4 [iJO.COOC 2 H 5 . Chlorohydrate, m.p. 151 (C. 1900, I. 413 ; 
 1904, II. 94, 695). This transformation of the O-acyl compounds of 
 
AMIDO-PHENOLS 201 
 
 the o-amido-phenols into the isomeric N-acyl compounds is quite a 
 general reaction. It is so straightforward that the O-acyl-o-amido- 
 phenols can usually not be obtained (cp. the similar transformations in 
 the o-oxy-benzylamines and o-amido-benzyl alcohols, A. 332, 159 ; 
 364, 147). 
 
 o-Oxy-phenyl-urea NH 2 CONH[2]C 6 H 4 [i]OH, m.p. 154. o-Oxy- 
 phenyl-thiurea NH 2 CSNH[2]C 6 H 4 [i]OH, m.p. 161. 
 
 o-Oxy-diphenyl-amine OH[2]C 6 H 4 [i]NHC 6 H 5 , m.p. 70, produced 
 by the action of acetyl and benzoyl peroxide upon diphenyl-amine 
 (B. 42, 4003). 
 
 The Condensations of the o-Amido-phenols. (i) Benzoxazoles result 
 by the union of o-amido-phenol with carboxylic acids ; thus, with 
 acetic acid the product is ^-methyl-benzoxazole. (2) With phosgene it 
 is p,-oxy-benzoxazole, or carbonyl-amidc-phenol. The latter body is also 
 produced upon heating o-oxy-phenyl-urea (see above). (3) On heating, 
 o-oxy-phenyl-thiurea yields o-oxy-phenyl-mustard oil. (4) o-Oxy-ethyl- 
 anisidine, when heated with hydrochloric acid, becomes pheno-mor- 
 pholine (q.v.). (5) Oxidants convert o-amido-phenol into oxy-phenoxaziri 
 (q.v.). o-Amido-phenol and pyro-catechol condense to phenoxazin 
 (?..). 
 
 CH,CO S H /[i]O\rriT /i-Methyl-benzoxazol or 
 
 f[i]OH _ f ~ H[2]N^ 3 Ethenyl-amido-phenol 
 
 4 \[2]NH 2 COC1 2 /[i]0\ r nM /t-Oxy-benzoxazol- or 
 
 \ [2]N/ Carbonyl-amido-phenol 
 
 r W /W H NF, , ,, f[i]O\ rC TT w-Sulpho-hydro-benzo-thiazol 
 
 4 \[2]NHCSNH 2 * 4 \[2]N/ or Oxy-phenyl-mustard oil 
 
 , pheno . morpholin 
 
 m-Amido-phenol, m.p. 122, is obtained from m-nitro-phenol (B. 11, 
 2101), from theoxamic acid derivative of m-phenylene-diamine (B. 28, 
 R. 30) ; by melting up metalinic acid with caustic soda (B. 32, 2112), 
 and by heating resorcin to 200 with ammonium chloride and aqueous 
 ammonia. 
 
 Monoalkyl-m-amido-phenols (B. 27, R. 953 ; 22, R. 622). Dimethyl- 
 m-amido-phenol melts at 87 ; diethyl-m-amido-phenol boils about 280. 
 m-Amido-phenol and its alkyl derivatives are employed in the prepara- 
 tion of rhodamine dyes. 
 
 Consult B. 29, 501, for the action of phosgene upon the alkyl m- 
 amido-phenols. Trimethyl-m-amido-phenol C 6 H 4 [i]OH[3]N(CH 3 ) 3 OH, 
 see B. 29, 1533. 
 
 p-Amido-pnenol melts at 184 with decomposition, and sublimes. 
 It results (i) from p-nitro-phenol ; (2) from j3-phenyl-hydroxylamine ; 
 (3) by the action of the electric current upon nitro-benzol in strong 
 sulphuric acid solution ; its formation here is due to the rearrangement 
 of the j3-phenyl-hydroxylamine produced at first ; (4) from [5]-amido- 
 salicylic acid by elimination of CO 2 ; (5) by heating p-chloro-phenol 
 with ammonia in the presence of copper (C. 1909, I. 600). By 
 oxidation with silver oxide it yields quinone mono-imine. 
 
 It is oxidised to quinone by chromic acid, or by PbO.j and sulphuric 
 
202 ORGANIC CHEMISTRY 
 
 acid. Bleaching-lime converts it, as well as its substitution products, 
 into quinone chlorimides. p-Amido-phenol acts the same, and just as 
 readily, as phenyl-hydrazin upon aldehydes and ketones in dilute acetic 
 acid (B. 27, 3005). Ethers of p-amido-phenetol are produced by re- 
 duction of p-nitro-phenol ether (B. 34, 1935), as well as by the trans- 
 position of /S-phenyl-hydroxylamine with alcoholic H 2 SO 4 (B. 33, 
 3602). Methyl ether, p-anisidin, m.p. 56, b.p. 246. 
 
 p-Amido-phenetol, p-phenetidine NH 2 [4]C 6 H 4 [i]OC 2 H 5 is the ethyl 
 ether. It boils at 242. Boiling glacial acetic acid converts it into 
 
 p-acetamido-phenetol c.H 4 /NH.co.CH^ phenacetin, melting at 135, 
 
 \{j.(s z t & 
 which has been applied as an antipyretic. 
 
 The splitting up of phenacetin by 80 to 90 per cent, sulphuric acid 
 into acetic ether and p-amido-phenol is worthy of note (A. 309, 233). 
 On prolonged boiling with excess of acetic anhydride (B. 31, 2788), 
 phenacetin is converted into diacetyl-phenetidin (CH 3 CO) 2 NC 6 H 4 OC 2 H 5 , 
 m.p. 54, b.p. 12 182, which has an action similar to phenacetin, as 
 has also p-ethoxy-phenyl-succinimide, pyrantin (CH 2 CO) 2 NC 6 H 4 OC 2 H 5 , 
 melting at 155, which, it is claimed, does not have the unpleasant action 
 or after-effects peculiar to phenacetin (B. 29, 84). p-Phenetol-earba- 
 mide, " dulcin," NH 2 CO.NH[ 4 ]C 6 H 4 [i]OC 2 H 5 (B. 28, R. 78, 83), has a 
 very sweet taste. 
 
 m-Oxy-diphenyl-amine C 6 H 5 NH[3]C 6 H 4 [i]OH, melting at 82 and 
 boiling at 340, and p-oxy-diphenyl-amine, melting at 70 and boiling at 
 330, are formed on heating resorcin and hydroquinone with aniline 
 and zinc chloride (B. 22, 2909). For homologues, see C. 1902, I. 578. 
 p 2 -Dioxy-diphenyl-amine NH(C 6 H 4 [4]OH) 2 , m.p. 174, is obtained from 
 hydroquinone by heating with ammonia or with p-amido-phenol (B. 32, 
 689). The oxy-diphenyl-amines are closely related to the indo-phenol 
 dyes (see Quinones). p 2 -Amido-oxy-diphenyl-amine NH 2 C 6 H 4 NHC 6 H 4 
 OH, m.p. 166, is formed by the reduction of the corresponding nitro- 
 compound (B. 42, 1080) or by oxidation of a mixture of p-phenylene- 
 diamine and phenol with hypochlorite in the presence of copper salts 
 (C. 1909, I. 115). The solution of p-amido-p-oxy-diphenyl-amine in 
 alkalies soon acquires a blue colour with the formation of indamine. 
 p 2 -dimethyl-amido-oxy-diphenyl-amine N(CH 3 ) 2 C 6 H 4 NHC 6 H 4 OH, m.p. 
 161, see B. 35, 3085. 
 
 Diamido-phenols. [2 ,4]-Diamido-phenol (NH 2 ) 2 [2, 4]C 6 H 3 [i]OH 
 is obtained from [2, 4]-dinitro-phenol, and by the electrolytic reduction 
 of m-dinitro-benzol or m-nitro-aniline in sulphuric acid (B. 26, 1848). 
 The free base is very unstable, and its salts have been used as developers 
 in photography under the name amidol. 4, 5- and 2, 5-Diamido-phenols 
 are formed from the nitro-amido-phenols obtained by the action of 
 H 2 SO 4 upon the o- and p-nitro-diazo-imides (B. 30, 2096 ; 31, 2403). 
 
 m-Anilido-p-phenitidin C 6 H 5 NH[ 3 ]C 6 H 3 /W^ H5 ; see Hydrazin phenols 
 
 WL4J-iNi 2 
 
 for its formation. 
 
 Pieramic acid, [2]-amido-[3, 4]-dinitro-phenol C 6 H 2 (NH 2 ).(NO 2 ) 2 . 
 OH, is obtained by the reduction of picric acid with alcoholic Am 4 SH 
 or with sodium hydrosulphite. (For further dinitro-p-amido-phenols, 
 see B. 38, 1593.) It forms red needles, which melt at 165. 
 
 [2, 4, 6]-Triamido-phenol C 6 H 2 (NH 2 ) 3 .OH is obtained from picric 
 
DIAZO-PHENOLS 203 
 
 acid by the action of phosphorus iodide, or by tin and hydrochloric acid 
 (B. 16, 2400). When set free from its salts, it decomposes very quickly. 
 Its salts, with three equivalents of acids, crystallise well. The Hi-salt, 
 C 6 H 3 O(NH 2 ) 3 .3HI, crystallises in colourless needles. These salts colour 
 water which is faintly alkaline, and even spring water, a beautiful blue. 
 If ferric chloride be added to the solution of the hydrochloride, it will 
 become deep blue in colour, and brown-blue needles with metallic 
 lustre will separate ; they are HCl-amido-di-imido-phenol, or diamido- 
 quinone-imine, which dissolves in water with a beautiful blue colour. 
 
 An isomeric triamido-phenol has been prepared by reducing di- 
 quinoyl-trioxime (B. 30, 183). 
 
 [2, 3, 4, 5]-Tetramido-anisol (NH 2 ) 4 C 6 HOCH 3 (B. 25, 282). 
 
 Diazo-phenols. Phenol-diazo-chlorides HO.C 6 H 4 N 2 C1 result from 
 the action of nitrous acid upon the hydrochlorides of the amido-phenols. 
 
 The diazonium polyhaloids, nitrates, and sulphonates, with weak 
 acids, like acetic acid and carbonic acid, form, by the replacement of 
 a halogen atom, a nitroyl or a sulphoxyl in the o- or p-position by 
 hydroxyl-substituted diazo-phenols (B. 36, 2069 ; 39, 79 ; C. 1903, I. 
 393 ; 1907, II. 1785). The free diazo-hydrates of the o- and p-amido- 
 phenols anhydrate themselves, the yellow, so-called quinone diazides 
 being generated, probably by a transposition into the quinoid form 
 (cp. Vol. L, Diazo-methane, and B. 35, 888) : 
 
 p-Diazo-phenol cyanide HO[4]C 6 H 4 N 2 .CN, from the action of 
 potassium cyanide on the chloride, consists of yellow needles. Caustic 
 potash saponifies it to the potassium salt of diazo-phenol-carboxylie 
 acid HO.C 6 H 4 N 2 COOH. 
 
 Dibromo-diazo-phenol Br 2 [4, 6]C 6 H 2 (: O)(: N a )[i, 2], orange prisms, 
 m.p. 130 with decomposition (B. 39, 4248). 
 
 Dibromo-phenol-diazo-sulphonie acid C 6 H 2 Br 2 (OH)N 2 SO 3 H+2H 2 O 
 can be isolated from its potassium salt produced from the interaction 
 of potassium sulphite and dibromo-phenol-diazo-chloride. 
 
 p - Phenol - diazo - mereaptan hydrosulphide C 6 H 4 (OH).N 2 SH.SH 2 , 
 from the action of hydrogen sulphide upon diazo-phenol solutions, con- 
 sists of red needles melting at 75 with decomposition (B. 28, 3250). 
 
 p-Oxy-diazo-benzol-imideOH[i]C 6 H 4 [4]N 3 , m.p. about 20, explodes 
 at 150. From p-amido-phenol with nitrous acid. The potassium com- 
 pound exists in two forms, one colourless, the other blue, easily con- 
 vertible into each other. Both yield the same benzoyl compound, of 
 m.p. 81, which is also obtained from benzoyl-p-amido-phenol with 
 nitrous acid (C. 1907, II. 247). 
 
 Azoxy-phenols. p-Oxy-azoxy-benzol C 6 H 5 (N 2 O)C 6 H 4 [4]OH, m.p. 
 156, is obtained by the combination of p-nitroso-phenol with j8-phenyl- 
 hydroxylamine and elimination of water ; it also forms on the action 
 of sodium hydroxide upon nitroso-benzol at 100, which also produces 
 two isomeric o-oxy-azoxy-benzols, m.p. 76 and 108 respectively. 
 Oxidation with permanganate disintegrates the oxy-azoxy-benzols to 
 potassium iso-diazo-benzol : 
 
 C 6 H 5 (N 2 O)C 6 H 4 OH -- > C 6 H 5 N 2 OK 
 (B. 35, 1614). 
 
204 ORGANIC CHEMISTRY 
 
 Azo-phenols, Oxy-azo-benzols. Formation: (i) From diazo-salts 
 and monohydric phenols, m-dioxy-benzols, m-amido-phenols, and 
 m-phenol-sulphonic acids : 
 
 C 6 H 5 N a .N0 3 +C 6 H 5 OH == C 6 H 5 N : N[i]C 6 H 4 [ 4 ]OH. 
 
 The solution of the diazo-salt is allowed to run into the alkaline 
 phenol solution while cooling and stirring. Phenol-diazo-benzol is 
 produced, together with phenol-azo-benzol. 
 
 As with the amido-azc-compounds, the entering diazo-group ar- 
 ranges itself in the phenols in the p-position, and when this is already 
 occupied it takes the o-position with reference to the hydroxyl group 
 (B. 17, 1876 ; 21, R. 814). 
 
 Intermediate products have been sometimes isolated in this reaction 
 in the form of the so-called o-azo-compounds (diazo-oxy-benzols), 
 corresponding to the diazo-amido-compounds, which, however, trans- 
 pose themselves with even greater ease into the isomeric oxy-azo-com- 
 pounds (B. 41, 4016, 4304) : 
 
 C 6 H 5 O.N : N.C 6 H 5 --- > C 6 H 5 N : N.C 6 H 4 OH. 
 
 (2) By heating the diazo-amido-benzols with monohydric phenols, 
 and also with resorcin (B. 20, 372, 904, 1577) : 
 
 C 6 H B .N 2 .NH.C 6 H B +C 6 H 6 .OH == C 6 H 5 .N 2 .C 6 H 4 .OH+C 6 H 5 .NH 2 . 
 
 (3) By the molecular rearrangement induced by heating azoxy- 
 benzols with sulphuric acid (B. 14, 2617) : 
 
 -- > C 6 H 5 N 2 .C 6 H 4 .OH 
 Azoxy-benzol Oxy-azo-benzol. 
 
 (4) By reduction of the nitro-phenols in alcoholic potassium hydrox- 
 ide solution. 
 
 (5) By the action of anilines upon nitroso-phenols. 
 
 (6) From amido-azo-benzols and from azo-benzol-sulphonic acids. 
 Constitution, The oxy-azo-compounds, containing hydroxyl in the 
 
 ortho-position to the azo-group, are probably quinone-hydrazones : 
 
 r H I OH r TT / : r w <f 
 
 CeJ:l4 \N:NC 6 H 5 CeH4 l :NNHC 6 H 6 l ^^ \ ftNHC 6 H 5 
 
 Oxy-azo-benzol Quinone-phenyl-hydrazone. 
 
 Quinone-phenyl-hydrazone itself is not obtained by condensation 
 of benzo-quinone, since the quinone is reduced by phenyl-hydrazin, 
 but the monophenyl-hydrazins of quinone have been obtained with 
 o-nitro- and o-, p-dinitro-phenyl-hydrazin. The latter have proved 
 themselves to be identical with the nitro-oxy-azo-compounds obtained 
 by coupling diazotated o-nitro- and o-, p-dinitro-aniline with phenol 
 (A. 357, 171 ; see also Naphtho-quinone-hydrazones) : 
 
 f[l]0 H 1 N.NHC S H 4 N0 2 / [l]N : NC 6 H 4 NO, ClN:NC 6 H 4 NO a 
 
 C H * \ [ 4 ]0 ~ C H4 \ [ 4 ]OH C 6 H 5 OH. 
 
 Unsym. acetyl- and benzoyl-phenyl-hydrazin also yield n-acylated 
 quinone-phenyl-hydrazones with quinone, and these, on saponification, 
 pass into p-oxy-azo-benzol. They are isomeric with the o-acyl-oxy- 
 
/ 
 6 4 L 
 
 AZO-PHENOLS 205 
 
 azo-benzols obtained by acetylation or benzoylation of oxy-azo-benzol 
 (C. 1900, I. 30). 
 
 Of special importance for deciding the question of the constitution 
 of the oxy-azo-compounds is the observation that the N-acylated p- 
 quinone-phenyl-hydrazones are transposed with great facility into the 
 isomeric O-acylated oxy-azo-benzols (B. 40, 1432) : 
 
 [i] : N.N(COCH 3 )C 6 H 5 _ /[i]N : NC.H 6 
 
 O ^M [ 4 ]0(COCH 3 )- 
 
 The tendency to pass into true azo-compounds is so great among 
 the o-quinones that the isomeric N-acylated o-quinone-phenyl-hydra- 
 zones have not been obtained at all up to the present time (B. 40, 
 2154 ; A. 359,353 ; but cp. C. 1909, 1. 1093). On account of this easy 
 conversion of derivatives of quinone-phenyl-hydrazone into those of 
 oxy-azo-benzol, we are justified in regarding the free o- and p-oxy-azo- 
 compounds as true azo-compounds. This is in agreement with the 
 fact that the m-oxy-azo-benzol (see below), which, on account of the 
 non-existence of m-quinones, cannot be formulated as a quinone-phenyl- 
 hydrazone, closely corresponds in its behaviour to o- and p-oxy-azo- 
 benzol (B. 36, 4118). With phenyl cyanate, o- and p-oxy-azo-benzol 
 
 combine to O-carbanilido-derivatives, QH^OCON^H ' B ' 38 ' I0 9 8 )' 
 The total or partial insolubility of oxy-azo-compounds in alkalies, 
 which was regarded as a special argument in favour of their 
 quinone structure, finds its analogy in the similar behaviour of the 
 phenyl-hydrazones of the o-phenol-aldehydes and ketones (B. 35, 4100 ; 
 C. 108, II. 306). 
 
 p-Oxy-azo-benzol, benzol-p-azo-phenol C 6 H 5 N=N[i]C 6 H 4 [4]OH, 
 m.p. 148, crystallises in orange-yellow needles. It is produced by the 
 methods mentioned in connection with oxy-azo-derivatives ; treated 
 with phosphorus pentachloride, and then with water, it is converted 
 into the phosphoric ester PO(OC 6 H 4 N 2 C 6 H 5 ) 3 , m.p. 148 (B. 24, 365 ; 
 cp. 35, 1622). Benzol-p-azo-phenetol, m.p. 77 (B. 25, 994). p-Azo- 
 phenol HO[4]C 6 H 4 [i]N 2 [i]C 6 H 4 [4]OH, m.p. 204, consists of light- 
 brown crystals. It is produced : 
 
 (1) By fusing p-nitro- and nitroso-phenol with caustic alkali. 
 
 (2) By the pairing of diazo-benzol nitrate with phenol. 
 
 (3) From p-oxy-azo-benzol-sulphonic acid (B. 15, 3037). 
 o-Oxy-azo-benzol, m.p. 83, is volatile with water vapour, therein 
 
 contrasting with the p-derivative ; it is formed beside the p-oxy-azo- 
 benzol in small quantities from benzol-diazonium salts with phenol 
 (B. 33, 3189) ; also by transposition of azoxy-benzol (C. 1903, I. 324, 
 1082) ; and partly by the action of NaHO upon nitroso-benzol (B. 33, 
 1939). Its methyl ether, benzol-azo-o-anisol, m.p. 41, obtained 
 synthetically from o-anisidin and nitroso-benzol, also yields with 
 A1 2 C1 6 the o-oxy-azo-benzol (B. 33, 3190). 
 
 m-Oxy-azo-benzol, m.p. 114-! 17, canary-yellow crystals, is 
 formed by the coupling of o-amido-phenetol with diazo-benzol chloride, 
 with splitting off of the amido-group, and saponification of the resulting 
 benzol-azo-m-phenetol, m.p. 64, with A1 2 C1 6 (B. 36, 4102) : 
 
 f[i]OC,H 5 
 
 C.I-1 . f [I]OC * H > > C 6 H t [ 2 ]NH 2 _ > c.H, ( OC * U * * C,H< ) OH 
 
 I [a]NH. I [5N . 2 NCHs ' H ' \ [ 5 ]N : NC.H. "' ( [ 5 JN : NC.H S 
 
206 ORGANIC CHEMISTRY 
 
 mm'-Dioxy-azo-benzol, m-azo-phenol, m.p. 205, is formed by 
 fusing m-nitro-phenol with caustic potash (B. 39, 303). It has also 
 been prepared from m-azo-aniline, by means of diazo-compounds, 
 and from m-nitro-phenol by electrol3'tic reduction (C. 1902, II. 1182 ; 
 1903, I. 1221). 
 
 Concerning azo- and diazo-compounds of cresol, see B. 17, 351. 
 
 The sulpho-acids of the oxy-azo-benzols are dyes e.g. p-sulpho- 
 benzol-p-azo-phenol SO 3 H[4]C 6 H 4 [i]N=N[2]C 6 H 4 [4]OH, from p-oxy- 
 azo-benzol and sulphuric acid, and from p-diazo-benzol-sulphonic 
 acid by means of sodium phenate, is the tropaoline yellow of commerce 
 (B. 11, 2192). Also compare resorcin. 
 
 Phenol-2, 4-dis-azo-benzol OH[i]C 6 H 3 [2, 4](N : NC 8 H 5 ) 2 , m.p. 123 
 (C. 1904, II. 96), and phenol-2, 4, 6-tris-azo-benzol OH[iJC 6 H 2 [2, 4, 6] 
 (N : NC 6 H 5 ) 3 , m.p. 215, are formed by coupling phenol with 2, or 3, 
 molecules of diazo-benzol chloride in alkaline solution. Tin and HC1 
 reduce phenol-tris-azo-benzol to 2, 4, 6-tri-amido-phenol (/. pr. Ch. 2, 
 78, 384). 
 
 HYDRAZO-PHENOLS. 
 
 m - Oxy - hydrazo - benzol OH[i]C 6 H 4 [3]NH.NHC 6 H 5 , colourless 
 needles, m.p. 126, is obtained by reduction of m-oxy-azo-benzol 
 with zinc dust and glacial acetic acid (B. 36, 4112). Mineral acids 
 transpose it into m-oxy-benzidin. m-Oxy-hydrazo-benzol is the only 
 known free oxy-hydrazo-compound, since o- and p-oxy-azo-benzol, 
 on reduction, decompose at once into aniline and o- or p-amido- 
 phenol respectively. But the alkyl ethers of the oxy-azo-benzols 
 may be reduced to the benzol-o- and p-hydrazo-phenol ethers. Benzol 
 p-hydrazo-phenol ethers undergo, with stannous chloride and HC1, 
 the semidin transposition. Thus, benzol-p-hydrazo-phenetol passes 
 into m-ethoxy-o-amido-diphenyl-amine (B. 27, 2700 ; 28, R. 753 ; 
 29, 2680) : 
 
 C,H 6 NHNH[i]C 6 H 4 [ 4 ]OC 2 H 5 
 
 The free hydrazin-phenols are very unstable. o-Hydrazin-anisol 
 NH 2 NH[2]C 6 H 4 [i]OCH 3 , m.p. 43, b.p. 240, see A. 221, 314. 
 
 Sulphonic Acids of Phenol. The sulphonation of phenol proceeds 
 with the replacement of the o- and p-hydrogen atoms, just as in the 
 nitration process (the sulpho-groups enter the meta-position with 
 reference to one another) : 
 
 ~TT f[i]OH 
 
 - - c e H 4 l[2]SOH _ , 
 
 C 8 H 5 OH I ( ' ? c H ) 
 
 I 
 
 l[6]S0 3 H 
 
 o- and p-Phenol-sulphonic acids are formed when phenol dissolves 
 in concentrated sulphuric acid ; at medium temperatures the former 
 is the more abundant, but readily passes into the para- on the applica- 
 tion of heat, or even upon boiling with water. This change is due to 
 the fact that o-phenol-sulphonic acid easily sheds its sulpho-group 
 with regeneration of phenol, which then forms p-phenol-sulphonic acid 
 under the influence of sulphuric acid. o-Phenetol-sulphonic acid is 
 
SULPHONIC ACIDS OF PHENOL 207 
 
 just as easily changed to the p-acid by heating it to 100 (B. 27, 
 
 R. 591)- 
 
 The separation of o- and p-phenol-sulphonic acid succeeds through 
 the crystallisation of its mono-barium salts, the barium ortho- 
 salt (C 6 H 4 )OH(SO 3 ) 2 B + H 2 O crystallising first in coarse needles of 
 the rhombic system. The p-acid is best obtained from the mother- 
 liquor, as in the magnesium salt (C 6 H 4 )OH(SO 3 ) 2 Mg+8H 2 O, large 
 rhombic columns (B. 40, 3637). The p-acid is also formed by trans- 
 position of phenyl-sulphuric acid. 
 
 The free acids can be obtained in crystalline form by the slow 
 evaporation of their aqueous solution. The aqueous solution of the 
 ortho-acid is applied as an antiseptic under the name of aseptol (B. 18, 
 R. 506). The para-acid yields quinone if its sodium salts be oxidised 
 with MnO 2 and sulphuric acid. When the ortho-acid is fused with 
 KOH at 310 it yields pyrocatechin or o-dioxy-benzol ; the para-acid 
 does not react at 320, and at higher temperatures yields diphenols 
 (see Diphenyl). 
 
 The action of nitric acid leads easily to the replacement of the 
 sulpho-group by the nitro-group. 
 
 With PC1 5 the phenol-sulphonic acids give, in the first place, the 
 phosphor-oxy-chloride derivative of the phenol-sulphonyl chlorides, 
 which, on heating to 180 with PC1 5 , are converted into those of the 
 chloro-phenols. On further heating of the latter with PC1 5 , we get 
 chloro-benzols : 
 
 r w /M 011 . r M /[i]OPOCl 2 ^ r /[i]OPOQ 2 ~ J[i]Cl 
 
 c M[4]so 3 K - c <M[ 4 ]so 2 ci C6 M[ 4] ci c 'M[ 4 ]cr 
 
 These reactions may be used to determine the location of the 
 sulphoxyl (B. 6, 943 ; A. 358, 92). If phenyl-sulphonyl chlorides are 
 required for reactions, it is best to acetylate the potassium-phenol 
 sulphonates, then to prepare the acetyl-phenol-sulphonyl chlorides, 
 and finally to remove the acetyl (Anschiitz). 
 
 From acetyl-phenol-o-sulphonile chloride we obtain, by the action 
 of ammonia, or, better, of diethyl-amine in etheric solution, and with 
 shedding of the acetyl-chloride constituents, phenylene-sulphonylide 
 
 CeH4 ([2]SO^O[i]} C6H4 ' m ' p - 237 ' corres P ndin S to salicylide, as 
 suggested by the name. 
 
 lodination of para-sulphonic acid yields [2, 6]-di-iodo-p-phenol- 
 sulphonic acid C 6 H 2 I 2 (OH).SO 3 H, which is used as an antiseptic under 
 the name sozo-jodol (B. 21, R. 250). 
 
 Meta-phenol-sulphonic acid [1, 3] is produced when meta-benzol- 
 disulphonic acid is heated to I70-i8o with aqueous potassium 
 hydroxide (B. 9, 969). The free acid contains two molecules of H 2 O. 
 Fusion with potassium hydroxide at 250 converts it into resorcin [i, 3]. 
 When para-benzol-disulphonic acid is heated with caustic alkali, 
 meta-phenol-sulphonic acid is also produced at first, but it yields 
 resorcin later. 
 
 Phenol- [2, 4]-disulphonic acid results from the action of an excess 
 of sulphuric acid upon phenol, also upon [i, 2]- and [i, ^-phenol- 
 sulphonic acid. The solutions of the acid and its salts are coloured a 
 dark red by ferric chloride. 
 
208 ORGANIC CHEMISTRY 
 
 Phenol- [2, 4, 6]-trisulphonie acid is obtained when concentrated 
 sulphuric acid and P 2 O 5 act upon phenol. It crystallises in thick 
 prisms with 3jH 2 O. 
 
 Nitro-phenol-sulphonic acids, see /. pr. Ch. 2, 73, 519. 
 
 p-Amido- phenol -sulphonic acid NH 2 [4]C 6 H 3 (OH)[i]SO 3 H[ 2 ] is 
 formed in small quantity by the action of concentrated H 2 SO 4 upon 
 nitro-benzol. There is probably a reduction to /3-phenyl-hydroxyl- 
 amine, followed by formation of p-amido-phenol and then amido- 
 phenol-sulphuric acid (C. 1908, II. 587). For other amido-phenol- 
 sulphonic acids, see B. 28, R. 378, 399 ; 39, 3345 ; C. 1904, I. 1235). 
 
 THIO-DERIVATIVES OF PHENOL. 
 
 Mercaptans. Thio-phenol, phenyl-mercaptan [pheno-thiol] C 6 H 5 SH, 
 boiling at 168, with specific gravity 1-078 (14), is a mobile, ill-smelling 
 liquid. It is made (i) by letting P 2 S 5 act upon phenol (Z. f. Ch. 1867, 
 193) ; (2) by distilling sodium benzol-sulphonate with potassium 
 sulphydrate (B. 17, 2080) ; (3) by reduction of benzol-sulpho-chloride, 
 or benzol-sulphinic acid, with zinc and sulphuric acid, or stannous 
 chloride (C. 1900, 1. 252 ; B. 32, 1147 ; C. 1904, II. 98) ; (4) from pheriyl- 
 dithio-carbonic ester ; (5) from phenyl-magnesium bromide, with 
 sulphur, the compound C 6 H 5 3MgBr being formed first, and then 
 decomposed by acids with rejection of thio-phenol (C. 1908, II. 1349 ' 
 1909, II. 193). It manifests great tendency to throw off hydrogen and 
 become phenyl disulphide ; hence it often acts as a reducing agent (cp. 
 B. 29, R. 979) . Mercury thio-phenate (C 6 H 5 S) 2 Hg. Thio-phenyl-acetal 
 C 6 H 5 .S.CH 2 .CH(OC 2 H 5 ) 2 , b.p. 273 (B. 24, 160). Thio-phenyl-acetone, 
 m.p. 34, and b.p. 266 (B. 24, 163). Consult B. 24, 234; 28, 1120 ; 
 A. 253, 161, for mercaptal (Vol. I.) and mercaptal derivatives of thio- 
 phenol. Phenyl-ortho-thio-formic ester C 6 H 5 S.CO 2 .C 2 H 5 , m.p. 39 
 (B. 25, 347, 252). Phenyl-dithio-carbonic ester C 6 H 5 S.CSOR is formed 
 from diazo-benzol chloride and potassium xanthogenate ; it represents 
 a common reaction (C. 1900, 1. 252). It yields thio-phenol when saponi- 
 fied. This is the most convenient way of preparing thio-phenols (B. 21, 
 R. 915), next to the reduction of the sulphinic acids. Phenyl-thio- 
 carbonic chloride C 6 H 5 S.COC1, b.p. 13 104, and phenyl-dithio-carbonic 
 chloride C 6 H 5 S.CSC1, b.p. 15 135, are formed by the action of phosgene 
 and thio-phosgene upon sodium thio-phenate. Both compounds, 
 treated with alcohol, phenol, thio-phenol, aniline, etc., have given rise 
 to many thio-phenol derivatives (C. 1907, II. 1159). 
 
 Diazo-benzol- thio-phenyl ether C 6 H 5 N 2 .SC 6 H 5 , an oil, is produced 
 from diazo-benzol chloride and phenyl-mercaptan (B. 28, 3237). 
 
 o-Thio-cresol,m.p. 15 and b.p. 188 ; them-body is a liquid, boiling 
 at I95-202, while the p-compound melts at 43 and boils at 194. 
 Thio-carvacrol (CH 3 )(C 3 H 7 )(C 6 H 3 SH), b.p. 235, see Carvacrol. For 
 further thio-phenols, see B. 32, 1147 ; C. 1908, II. 1349. 
 
 o-Nitro-thio-phenol NO 2 [2]C 6 H 4 SH, m.p. 45, easily obtained from 
 o-nitro-chloro-benzol with sodium sulphide ; it easily oxidises to the 
 disulphide (NO 2 [2]C 6 H 4 ) 2 S 2 , m.p. 198, which is also easily obtained 
 from o 2 -dinitro-benzol with sodium sulphide, and from o-nitro-chloro- 
 benzol with alkaline poly-sulphides ; p-nitro-chloro-benzol is similarly 
 transformed into p - nitro - phenyl - disulphide (NO 2 [4]C 6 H 4 ) 2 S 2 . By 
 
THIO-DERIVATIVES OF PHENOL 209 
 
 oxidation of these disulphides with HNO 3 we obtain the corresponding 
 nitro-benzol-sulphonic acids (/. pr. Ch. 2, 66, 551). 
 
 Of the substitution products of thio-phenol, the o-amido-thio-phenol 
 should be noted on account of its heterocyclic condensation products. 
 
 o-Amido-thio-phenol NH 2 [2]C 6 H 4 [i]SH is obtained from ortho- 
 nitro-benzol-sulphonic chloride by reduction with tin and hydrochloric 
 acid. A better method to pursue is to fuse benzenyl-o-amido-thio- 
 phenol with caustic potash (B. 20, 2259). It melts at 26 and boils 
 at 234. 
 
 m-Amido-thio-phenol (B. 27, 2816). p-Amido-thio-phenol, m.p. 
 46, by reduction of aceto-sulphanilic chloride (B. 42, 3362). 
 
 The Condensations of the o-Amido-thio-phenols (compare o-diamines 
 and o-amido-phenols). (i) Benzo-thiazols are formed on heating 
 o-amido-thio-phenol with carboxylic acids, acid chlorides, or acid 
 anhydrides. (2) o-Amido-thio-phenol, by the action of chloro-carbonic 
 esters, forms ^-oxy-benzo-thiazol or carbonyl-amido-thio-phenol. (3) 
 With chloro- or bromo-acetic acid it yields keto-dihydro-benzo- 
 thiazin (q.v.). (4) Carbon disulphide produces /x-sulphydro-benzo- 
 thiazol (q.v.). (5) Nitrous acid converts o-amido-thio-phenol into 
 o-phenylene-diazo-sulphide (q.v.) ; at 200-22O this becomes dipheny- 
 lene disulphide : 
 
 CHjCOj H f [j]s \^ /i-Methyl-benzo-thiazol 
 
 n *| [ 2 ]N^ Ethenyl-amido-thio-phenol 
 
 C1CO,C,H S fms\ fr T -K fi-Oxy-benzo-thiazolor 
 
 > C.H 4 -[ J IJ ^ \C.OH or C.H, j L J ~>CO Carbonyl-o-amido- 
 
 v. L^j^'y v L^JWrl thio~phcDol 
 
 CH t Cl.COOH f [I]S CH, 
 
 *-"* " f2lNH CO Keto-dihydro-benzo-thiazin 
 
 o-Amido-thio- 
 phenol 
 
 CS 
 
 NOOH 
 > 
 
 C.H 4 [I]S C.SH M-Sulphydro-benzo-thiazol 
 C.H | [I]S \N o-Phenylene-diazo-sulphide. 
 
 See below for the condensation of o-amido-thio-phenol with pyro- 
 catechol to thio-diphenyl-amine. 
 
 Sulphides. Phenyl disulphide (C 6 H 5 ) 2 S 2 , m.p. 61 and b.p. 310, 
 results from the oxidation of thio phenol with a chromic acid mixture, 
 or in ammoniacal solution, by the oxygen of the air ; by the action of 
 iodine upon aqueous potassium thio-phenate ; by heating thio-phenol 
 with benzol-sulphinic acid ; by heating thio-phenol or phenyl sulphide 
 with sulphur, etc. Reducing agents decompose it into two molecules 
 of thio-phenol, and alcoholic potash breaks it down into potassium 
 thio-phenate and potassium-benzol sulphinate (B. 41, 3403). 
 
 p 2 -Diamido-diphenyl disulphide, dithio-aniline S 2 [C 6 H 4 NH 2 ] 2 , m.p. 
 77, is produced besides thio-aniline on melting up sulphur with aniline 
 and aniline chlorohydrate. On reduction, or on boiling with alcoholic 
 KHO, it is converted into p-amido-thio-phenol (B. 39, 2427). The 
 diacetyl compound exists in three isomeric forms of m.p. 215, 182, 
 and 122 respectively. This isomerism is not as yet explained (B. 41, 
 626). Dithio-m-toluylene-diamine, see B. 42, 743. 
 
 Phenyl sulphide (C 6 H 5 ) 2 S, benzol sulphide, a colourless liquid, with 
 
 an odour resembling that of leeks, b.p. 292, has a specific gravity 
 
 of i -12. It is formed (i) by distilling phenol with P 2 S 5 (along with 
 
 thio-phenol) ; (2) from sodium-benzol sulphonate with P 2 S 5 ; (3) by 
 
 VOL. II. P 
 
2io ORGANIC CHEMISTRY 
 
 heating mercury-diphenyl with sulphur (B. 27, 1171) ; (4) on heating 
 sulphur with diphenyl sulphone (method of preparation), into which 
 it is also converted by oxidants (B. 26, 2816) ; (5) by the action of 
 sulphur hypochloride or finely divided sulphur and Al chloride upon 
 benzene (C. 1905, II. 228). The two last methods are specially suitable 
 for preparing phenyl sulphides. (6) Phenyl sulphide and its homologues 
 are also readily prepared by heating aromatic lead mercaptides with 
 haloid benzols (the bromides are the best adapted for this purpose) 
 (B. 28, 2322), or sodium mercaptides with iodo-benzols in the presence 
 of powdered copper (B. 39, 3593). 
 
 Diphenylene sulphide or dibenzo-thio-phene (q.v.) is produced on 
 conducting the vapours of phenyl sulphide through a tube heated to 
 redness. 
 
 Fatty aromatic sulphides, which may also be regarded as alcohol 
 ethers of thio-phenols, are produced (i) by the action of iodo-alkylene 
 or dimethyl sulphate upon the sodium salts of the thio-phenols ; (2) by 
 heating phenyl-dithio-carbonic ester alone : 
 
 C 6 H 5 S.CSOC 2 H 5 = = C,H 5 SC a H 5 +COS ; 
 
 (3) by successive action of sulphur and iodo-alkylene upon phenyl- 
 magnesium bromide (C. 1905, I. 80) : 
 
 C 6 H 5 MgBr -> C 6 H 5 SMgBr '-> C 6 H 5 SCH 3 . 
 
 Phenyl-methyl sulphide C 6 H 5 SCH 3 , b.p. i87-i90 ; phenyl-ethyl 
 sulphide C 6 H 5 SC 2 H 5 , b.p. 200-2o6. The fatty aromatic sulphides 
 easily add two atoms of bromine or iodine, with formation of dibromides 
 or di-iodides, usually crystallising easily, which, under the action of 
 water, exchange the halogen for oxygen, and form mixed sulph-oxides. 
 
 Phenyl-thio-glycolic acid C 6 H 5 SCH 2 COOH, m.p. 43-5, is formed 
 
 (1) from sodium thio-phenate and monochloracetic acid ; (2) by the 
 action of thio-glycolic acid upon diazo-benzol chloride in aqueous 
 solution. In this action the compound C 6 H 5 N 2 S.CH 2 COOH is formed 
 first, and passes, on warming, into phenyl-thio-glycolic acid, with 
 rejection of nitrogen (M. 28, 247 ; C. 1908, I. 1221). 
 
 With dimethyl sulphate the aromatic and fatty aromatic sulphides 
 combine to mixed sulphinic or sulphonium compounds, which change 
 in stability with the number of aromatic radicles. Thus, diphenyl- 
 methyl-sulphonium chloride decomposes on boiling with water, and 
 rapidly on adding alkali, into methyl alcohol and diphenyl sulphide 
 (B. 39, 3559). 
 
 Amido-phenyl Sulphides or Thio-anilines. Formation : (i) These 
 compounds result when nitro-thio-phenyls are reduced (cp. B. 29, 2362) ; 
 
 (2) from anilines by boiling the latter with sulphur and lead oxide 
 (B. 4, 384). Sulphur chloride converts the dialkyl-anilines into sym. 
 p-tetra-alkyl-diamido-phenyl sulphides. Silver nitrate and ammonia 
 desulphurise the tetra-alkyl compounds, with the formation of sym. 
 p - tetra - alkyl - diamido - diphenyl oxides e.g. O[C 6 H 4 [4] .N(CH 3 ) 2 ] 2 
 (B. 21, 2056). Upon heating methyl-thio-anilines e.g. thio-p-toluidin 
 with sulphur to higher temperatures, thiazol derivatives, like 
 dehydro-thio-toluidin (see Benzo-thiazol), are produced. 
 
 p-Diamido-diphenyl sulphide s<, thio-aniline, melts at 105. 
 
THIO-DERIVATIVES OF PHENOL 211 
 
 o-Diamido-diphenyl sulphide melts at 93 (B. 27, 2807). See B. 38, 
 1130 for isomeric thio-anilines, melting at 80 and 86. 
 
 Thio-p-toluidin K^(CI)NH!' diamido-ditolyl sulphide, melts 
 at 103. The sodium salts of thio- and dithio-toluidin-sulphonic acids 
 dye unmordanted cotton a greenish yellow (B. 21, R. 877). They are, 
 therefore, so-called substantive cotton dyes. 
 
 The bis-diazo-salts of thio-p-toluidin, which may be produced in 
 the fibre itself, combine with naphthyl-amine-sulphonic acids, and 
 yield diazo-dyes of a brown-red colour (B. 20, 664). 
 
 Thio-diphenyl - imides. Thio-diphenyl-amine S { ^'^ }NH, j s 
 
 W[IJ^6 i:1 4L 2 J J 
 
 the simplest of these heterocyclic bodies. Methylene blue, a most 
 valuable dye, is derived from it. The thio-phenyl-amine group will be 
 discussed later with the hetero six-ring compounds. 
 
 Thio-anisol S(C 6 H 4 OCH 3 ) 2 , melting at 46, and allied bodies, are 
 formed when thionyl chloride or sulphur chloride with aluminium 
 chloride acts upon the phenol ethers (A. 27, 2540). 
 
 Seleno-phenols. Like sulphur, selenium also attaches itself to 
 phenyl-magnesium bromide, forming C 6 H 5 SeMgBr, from which seleno- 
 phenol is produced with dilute acids. 
 
 Seleno-phenol C 6 H 5 SeH, b.p. 182, is also formed by reduction of 
 benzol-seleninic acid and diphenyl diselenide, into which it easily 
 passes by oxidation in air. p-Seleno-cresol, white flakes, m.p. 47 
 (C. 1906, II. 1119). 
 
 Phenyl selenides and tellurides are quite readily obtained from the 
 mercury-diphenyl compounds by the action of selenium and tellurium. 
 
 Diphenyl selenide (C 6 H 5 ) 2 Se also results upon heating selenium 
 with diphenyl sulphone. Sulphur dioxide escapes at the same time. 
 It boils at 163 (14 mm.). Further action of selenium produces diphenyl 
 diselenide (C 6 H 5 ) 2 Se 2 , melting at 63 and boiling at 203 (n mm.). 
 Reduction changes it to two molecules of phenyl-selenium hydrate 
 C 6 H 5 SeH, melting at 183. Diphenyl telluride (C 6 H 5 ) 2 Te boils at 174 
 (10 mm.) ; see B. 28, 1670 ; 29, 428. Further aromatic Se and Te 
 compounds, see B. 30, 2821. 
 
 DIHYDRIC PHENOLS. 
 
 Several representatives of this family occur in plants, or have been 
 obtained as decomposition products of plant substances. Resorcin or 
 m-dioxy-benzol is especially important from a technical standpoint. 
 
 The general methods of formation are like those of the corresponding 
 monohydric phenols (i) by fusing monohalogen phenols, halogen 
 benzol-sulphonic acids, phenol-sulphonic acids, and benzol-disulphonic 
 acids with potassium hydroxide ; (2) by diazotising the amido-phenols ; 
 and (3) by aromatic dioxy-acids alone or with lime or baryta. 
 
 (4) o- and p-Dioxy-benzols also result from the careful reduction 
 of their corresponding quinones. (5) o- and p-Dioxy-benzols are 
 obtained in a straightforward reaction by the oxidation of o- and p-oxy- 
 benzaldehydes and o- and p-oxy-aceto-phenones with H 2 O 2 in feeble 
 alkaline solution ; m-oxy-benzaldehyde gives no resorcin when treated 
 similarly (C. 1910, I. 634). 
 
 Behaviour. Their behaviour is largely dependent upon the position 
 
212 ORGANIC CHEMISTRY 
 
 of the two hydroxyl groups with reference to one another. The three 
 simplest dioxy-benzols, pyrocatechol [i, 2], resorcin [i, 3], hydroquinone 
 [1,4], are, therefore, typical representatives of the three groups of 
 dihydric phenols. The behaviour of such bodies can be fully illus- 
 trated through them. The dihydric phenols can be changed by 
 chlorine to hydro-aromatic keto-chlorides, whose carbon ring may be 
 readily ruptured. Chloroform and caustic potash convert them into 
 dioxy-aldehydes, while they yield dioxy-carboxylic acids with carbon 
 tetrachloride and caustic potash, as well as alkaline carbonate solutions. 
 
 Pyrocatechin Group. All o-dioxy-benzols are coloured green by 
 ferric chloride. They are further distinguished from the m- and 
 p-compounds by their ability to exchange their hydroxyl hydrogen 
 atoms and thus form cyclic esters readily. 
 
 Pyrocatechin, pyrocatechol, o-dioxy-benzol [i, 2-pheno-diol] C 6 H 4 
 [1,2] (OH) 2 , melting at 104 and boiling at 245, was first (Reinsch, 
 1839) obtained in the distillation of catechine (the juice of Mimosa 
 catechu), and also from Moringa tannic acid. 
 
 It is produced in fusing many resins with caustic potash. It occurs 
 in kino, the dried juice of different kinds of Pterocarpus, Butea, and 
 Eucalyptus, in beechwood tar, and has been obtained as a by-product 
 in the manufacture of paraffin from bituminous shales at the Messel 
 mine, near Darmstadt, etc. Pyrocatechol-sulphuric acid occurs in the 
 urine of the horse and in that of man. It is artificially made (i) by 
 oxidising phenol with hydrogen peroxide or with Caro's acid ; (2) by 
 the distillation of pyrocatechuic acid, or [i CO 2 H, 3, 4]-dioxy-benzoic 
 acid ; (3) by fusing [i, 2]-chloro-phenol, [i, 2]-bromo-phenol (B. 27, 
 R. 957), [i, 2]-benzol-disulphonic acid, and [i, 2]-phenol-sulphonic acid 
 with caustic potash ; (4) by heating guaiacol-pyrocatechol-monomethyl 
 ether to 200 with hydriodic acid. 
 
 On exposure to the air its alkaline solutions assume a green, then 
 brown, and finally a black colour. Lead acetate throws out a white 
 precipitate, PbC 6 H 4 O 2 , from its aqueous solution. Neither resorcin 
 nor hydroquinone shows this reaction. Similarly, the formation of 
 antimonyl compounds is characteristic of o-dioxy-benzols, e.g. C 6 H 4 O 2 . 
 SCOH (C. 1898, II. 598). Pyrocatechin reduces cold silver solutions and 
 alkaline copper solutions. The application of heat is required in the 
 latter case. Silver oxide oxidises it in etheric solution to o-benzo- 
 quinone. Pyrocatechin in glacial acetic acid solution is converted by 
 chlorine into tetrachloro-pyrocatechin, tetrachloro-o-quinone, and hexa- 
 chloro-o-diketo-R-hexene ; in nitrous acid, to dioxy-tartaric acid. Con- 
 sult p. 214 for the heterocyclic formations obtainable from pyrocatechol. 
 Heated with phthalic anhydride and sulphuric acid, it yields alizarine 
 and hystazarine. Compare protocatechuic aldehyde and protocatechuic 
 acid. It is used in photography as a developer. 
 
 Ethers. Some ethers of pyrocatechin, such as the mono- and 
 dimethyl ether, as well as the methylene ether, are of special import- 
 ance, as being closely connected with numerous vegetable substances, 
 such as eugenol, safrol, apiol, vanillin, piperonal, papaverin, etc. 
 
 Pyroeateehin-methyl ether, guaiacol, occurs in the creosote from 
 beechwood tar (B. 28, R. 156). It is produced on heating pyrocatechin 
 with potassium hydroxide and potassium-methyl sulphate to 180, as 
 well as by heating calcium vanillate, and from veratrol (B. 28, R. 362). 
 
PYROCATECHIN GROUP . 213 
 
 Ferric chloride gives its alcoholic solution an emerald-green colour (see 
 Vanillin). 
 
 p-Nitroso-guaiaeol C 6 H 3 [2, i](OCH 3 )(OH)[4]NO, from guaiacol with 
 sodium alcoholate and ethyl nitrite, gives on oxidation nitro-, and 
 on reduction amido-guaiacol C 6 H 3 (OCH 3 )(OH)NH 2 (B. 30, 2444). 
 
 Guaiacol-sulphonic acids, see B. 39, 3685 ; C. 1907, II. 1467. 
 Numerous guaiacol derivatives are extensively employed in the treat- 
 ment of pulmonary tuberculosis. 
 
 Dimethyl ether, veratrol C 6 H 4 [i, 2](OCH 3 ) 2 , melting at 15 and 
 boiling at 205, is prepared by treating the potassium salt of the mono- 
 methyl ether with CH 3 I, and by distilling vetraric acid with lime. 
 
 Pyroeateehin-methylene and ethylene ether, b.p. 173 and 216 
 respectively. 
 
 Glyoxal-dipyrocateehin (C 6 H 4 O 2 )CH.CH(O 2 C 6 H 4 ), m.p. 89, from 
 acetylene tetrabromide and sodium pyrocatechin, on hydrolysis, gives 
 o-oxy-phenoxy-acetie acid OHC 6 H 4 O.CH 2 COOH, m.p. 131, which 
 also forms direct from monosodium pyrocatechin and chloracetic acid 
 (/. pr. Ch. 2, 61, 345 ; C. 1900, II. 327), and easily passes into its 
 
 lactone C 6 H 4 <^ 2 > m.p. 55, b.p. 243 (B. 40, 2779). 
 
 <s~\ /"* TT 
 and propene-pyrocatechin are 
 
 formed from o-oxy-phenoxy-acetaldehyde and o-oxy-phenoxy-acetone 
 with acetyl chloride or P 2 O 5 (C. 1899, II. 620). 
 
 Pyrocatechin-diphenyl ether C 6 H 4 [i, 2](OC 6 H 5 ) 2 , m.p. 93, is formed 
 by heating o-dibromo-benzol with potassium phenate in the presence 
 of copper powder. Similarly, we obtain pyrocatechin-monophenyl ether 
 OH[i]C 6 H 4 [2]OC 6 H 5 ,m.p. 107, and o 2 -dioxy-phenyl ether [C 6 H 4 OH] 2 O, 
 m.p. 121, by melting o-bromanisol \vith potassium-phenol or guaiacol, 
 from the mono- or dimethyl ether formed at first. Heating with con- 
 centrated HBr transforms o 2 -dioxy-phenyl ether into diphenylene 
 
 dioxide c H {^o[2]} C6H4) m ' p - II9 (B ' 39 ' 622) ' 
 
 Mono- and" dibenzoyl ester, m.p. 130 and 84 (B. 26, 1076 ; A. 
 210, 261). 
 
 Pyrocatechin sulphite boils at 2io-2ii (B. 27, 2752) ; pyrocatechin 
 chloro-phosphine melts at 130 ; pyrocatechin oxy-ehloro-phosphine 
 melts at 35 (B. 27, 2569) (see below). 
 
 The carbonic ester C 6 H 4 -[^ \CO results from the action of chloro- 
 
 U. L2jU/ 
 
 carbonic ester upon pyrocatechin, melts at 118 and boils at 227. 
 Also from the action of PC1 5 upon pyrocatechin-methylene ether, and 
 decomposition of the resulting dichloro-pyrocatechin-methylene ether 
 
 C 8 H 4 {\CC1 2 with water (C. 1908, I. 1689). This reaction is of 
 
 importance, inasmuch as by its means the numerous derivatives of 
 pyrocatechin-methylene ether occurring in nature may be transformed 
 into pyrocatechin derivatives otherwise difficult to obtain ; cp. Pyro- 
 catechin-aldehyde. 
 
 By heating with alcohols or amine bases the pyrocatechin carboxy- 
 late is easily broken up into o-oxy-phenol-carbonic esters, or carba- 
 minic o-oxy-phenol esters ; with hydrazin hydrate it yields pyro- 
 cateehin-carbonic hydrazide HOC 6 H 4 OCONHNH 2 , which, in alcoholic 
 
214 
 
 ORGANIC CHEMISTRY 
 
 solution, reacts easily with aldehydes, but not with ketones (B. 13, 
 697 ; A. 226, 84 ; 300, 135 ; 317, 190). Oxalic ester, m.p. 185, from 
 sodium-pyrocatechin and oxal-ethyl-ester chloride (B. 35, 3452). 
 
 HETERO-RING FORMATIONS FROM PYROCATECHOL. By the replace- 
 ment of both hydroxyl hydrogen atoms of pyrocatechol, cyclic esters 
 are formed with SOC1 2 , PC1 3 , POC1 3 , COC1 2 , and ethylene bromide. 
 o-Phenylene-diamine, o-amido-phenol, and o-amido-thio-phenol con- 
 dense with pyrocatechin, forming phenazin, phenoxazin, and thio- 
 diphenyl-amine : 
 
 f[i]OH 
 C M[2]OH~ 
 
 SOC1 2 
 
 \[i O/^ Pyrocatechin sulphite 
 
 r[i]O\PCl Pyrocatechin chloro- 
 \[2]O/ phosphine 
 {[i]O\_._ . Pyrocatechin oxychloro- 
 [2]0/ phosphine 
 
 s r^Q/^ Pyrocatechin carbonate 
 
 {[i]O CH 2 Pyrocatechin-ethylene- 
 [ 2 ]O CH 2 ether 
 
 < ? J~ [ J ) C 6 H 4 Phenoxazin 
 
 \[2] NH [2]J 
 
 < rC 6 H 4 Thio-diphenyl-an 
 U [2] NH [2] ^ 
 
 PCJ 3 >r n 
 
 ->C 6 hL 4 
 
 15008 >c n 
 
 COC1, 
 
 ->^ 6 n 4 
 BrCH s CH 2 Br ^ 
 
 >Lx 6 xl 4 
 C,H 4 [i > 2](NH s ) z _^ c H 
 
 NH,[ 2 ]C,H 4 [i]OH c n 
 
 NH 2 [2]C,H 4 [i]SH ^ H 
 
 6 4 
 
 Homologous Pyrocatechols. Iso-homo-pyrocatechol CH 3 [i] C 6 H 3 [2,3] 
 (OH) 2 , m.p. 47 (B. 24, 4137). Homo-pyrocatechol CH 3 [i]C 6 H 3 [3, 4] 
 (OH) 2 , m.p. 51 and b.p. 251, occurs in the form of its 3-methyl ether 
 as ereosol CH 3 [i]C 6 H 3 [3](OCH 3 )[4]OH, b.p. 221, in beechwood tar, 
 together with phloral (B. 14, 2005). 
 
 Creosol is also formed together with guaiacol (see above) in the dis- 
 tillation of guaiacol resin. Higher homologues of pyrocatechol have 
 been obtained by treating pyrocatechol with aliphatic alcohols and 
 zinc chloride (B. 28, R. 312). 
 
 Ethyl-, propyl- and iso-propyl-pyroeateehin, m.p. 39, 60, and 78, 
 are obtained from the corresponding methylene ethers (C. 1904, I. 797 ; 
 II. 436). 
 
 Mono-thio-pyrocateehol C ? H 4 [i, 2](SH)(OH), m.p. +5 and b.p. 
 217, results from the reduction of diphenol disulphide [C 6 H 4 OH] 2 S 2 , 
 produced on heating sodium phenoxide with sulphur. o 2 -Dioxy- 
 diphenyl sulphide [C 6 H 4 OH] 2 S, m.p. 142, see B. 39, 1350. 
 
 Diphenylene disulphide, or thianthrene c 6 H 4 /f I ^f I Hc 6 H 4 , m.p. 
 
 L|_2jb[2J J 
 
 158 and b.p. 360, should be regarded as a derivative of dithio-pyro- 
 catechol C 6 H 4 (SH) 2 . It is made by boiling phenyl sulphide with 
 sulphur, also from benzene, SC1 2 , and aluminium chloride, as well as 
 by heating phenylene diazo-sulphide (C. 1899, II. 648 ; 1905, II. 228). 
 Also by the action of A1 2 C1 3 upon thio-phenol or phenyl disulphide 
 (C. 1909, I. 1652). HNO 3 oxidises it to thianthrene dioxide C 6 H 4 (SO) 2 
 C 6 H 4 , m.p. 230, which is transposed by heating to 270 into thianthrene 
 
 monosulphone C.HXH* m.p. 279. 
 
RESORCIN GROUP 215 
 
 Oxidation converts thianthrene into a disulphone, C 6 H 4 (SO 2 ) 2 C 6 H 4 . 
 When the latter is heated with selenium, diphenylene diselenide, selen- 
 anthrene C 6 H 4 : (Se 2 ) : C 6 H 4 , m.p. 181 and b.p. 223 (n mm.), results 
 (B. 29, 435, 443). 
 
 RESORCIN GROUP. 
 
 Resorcin, and many of its homologues, combine with phthalic anhy- 
 dride, the products being the fluoresceins (q.v.). The aqueous solutions 
 of the m-dioxy-benzols are coloured dark violet by ferric chloride. 
 
 Resorcin C 6 H 4 [i, 3](OH) 2 , m.p. 118 and b.p. 276, is produced 
 from galbanum, asafcetida, and other resins upon heating them with 
 potash, as well as by distilling the extract of Brazil-wood. It can also 
 be obtained from many m-disubstitution products of benzene, such as 
 [i,3]-chloro-andiodo-phenol, [i, 3]-phenol-sulphonic acid, [i,3]-benzol- 
 disulphonic acid, etc., on fusing them with potash or soda at 23O-28o ; 
 by the same method from umbelliferone. 
 
 Even o- and p-compounds (B. 7, 1175 ; 8, 365), especially when 
 fused at high temperatures with caustic alkali, yield resorcin ; hence 
 the potash fusion is not available in the determination of position. 
 Resorcin is made on a technical scale from m-benzol-disulphonic acid 
 (/. pr. Ch. 2, 20, 319)- 
 
 Properties and Behaviour. Resorcin crystallises in rhombic prisms 
 or plates. It dissolves readily in water, alcohol, and ether, but not in 
 chloroform or carbon disulphide. It possesses a sweet taste. Lead 
 acetate does not precipitate its aqueous solution (distinction from 
 pyrocatechin) . 
 
 Sodium amalgam reduces resorcin to dihydro-resorcin (A. 278, 20), 
 or m-diketo-hexamethylene (B. 27, 2129). Bromine precipitates it from 
 aqueous solution as tribromo-resorcin, m.p. 111, while chlorine con- 
 verts it in glacial acetic acid solution finally into heptachloro-resorcin 
 (B. 26, 498), which can be easily decomposed. Fusion with caustic 
 soda produces phloroglucin, pyrocatechol, and diresorcin (HO) 2 C 6 H 3 
 C 6 H 3 (OH) 2 (B. 26, R. 233). The chlorohydrate of a triresorcin 
 C 18 Hj 4 O 4 (A. 289, 61) is formed when resorcin is heated with hydro- 
 chloric acid. 
 
 Ethers and Esters. The monomethyl ether boils at 243 (B. 16, 151). 
 The dimethyl ether boils at 214 (B. 10, 868). The diacetyl ester boils 
 at 278 (B. 16, 552). The diearbonie ester C 6 H 4 (OCO 2 C 2 H 5 ) 2 boils at 
 300 (B. 13, 697). The dibenzoate melts at 117 (A. 210, 256). Resorcin 
 combines with the various sugars under the influence of hydrochloric 
 acid (B. 27, 1356). 
 
 Fluorescei'n is produced when resorcin is heated with phthalic 
 anhydride. 
 
 If resorcin be heated with sodium nitrite, it forms a deep-blue dye, 
 soluble in water. Acids turn this red (B. 17, 2617). It is used as an 
 indicator under the name of lacmoid (B. 18, R. 126). Nitric acid, 
 containing nitrous acid, converts resorcin into two dyes resorufin and 
 resazurin derivatives of phenoxazin (q.v.) (B. 23, 718). 
 
 When diazo-salts act upon aqueous or alkaline resorcin solutions, 
 azo-dyes and dis-azo-dyes are produced ; thus, with diazo-benzol 
 nitrate or chloride the products are : benzol-azo-resorcin (C 6 H 5 N 2 ) 
 C 6 H 3 (OH) 2 , a- and jS-diazo-benzol-dis-azo-resorcin (C 6 H 5 N 2 ) 2 C H 2 (OH) 2 
 
216 ORGANIC CHEMISTRY 
 
 (B. 15, 2816 ; 16, 2858 ; 17, 880) ; while with the diazo-chloride of 
 amido-azo-benzol there results azo-benzol-azo-resorcin C 6 H 5 N 2 .C 6 H 4 
 N 2 .CeH 3 (OH) 2 (B. 15, 2817). The action of amyl nitrite upon an 
 alkaline solution of resorcin produces 4-nitroso-resorein NO[4]C ? H 3 JX 3] 
 (OH) 2 (B. 35, 4191). On the other hand, dinitroso-resorein, diquinoyl- 
 dioxime C 6 H 2 [i, 3 ](OH) 2 [ 4 ,6](NO) 2 or C 6 H 2 (O) 2 (N.OH) 2 [i, 3, 2, 4] 
 crystallises in yellow-brown flakes, which detonate on heating to 
 115 C. (B. 20, 3133). It occurs in commerce under the names solid 
 green or chlorin (B. 20, 3133). 
 
 Nitroso-resorcin-monomethyl and -ethyl ether NO[4]C 6 H 3 [3]OH[i] 
 OCH 3 and -OC 2 H 5 respectively, exist each in two isomeric modifica- 
 tions, one of them being green and unstable, the other yellowish 
 brown and stable. On heating to 130 the former passes into the 
 latter. Both modifications yield the same alkali salt, from solutions 
 of which the yellowish-brown modification is precipitated by acids. 
 This isomerism is perhaps to be interpreted in the sense of the following 
 formulae : (RO)C 6 H 3 (OH)NO and (RO)C 6 H 3 : O : (NOH), according 
 to which the green form is to be regarded as a true nitroso-phenol, 
 and the yellow as o-quinone-monoxime (/. pr. Ch. 2, 70, 332). 
 
 v-Nitro-resorcin (NO 2 )[2]C 6 H 3 [i, 3](OH) 2 , m.p. 85, orange needles, 
 volatile with water vapour, is produced by nitrating resorcin-disulphonic 
 acid and splitting of the sulpho-groups with superheated steam (B. 
 37, 726). 
 
 v-Dinitro-resorein (NO 2 )[2, 4]C 6 H 2 [i, 3](OH) 2 , m.p. 148, by the 
 action of HNO 3 fumes upon resorcin. Iso-dinitro-resorcin (NO 2 ) 2 
 [4, 6]C 6 H 2 [i, 3 ]OH 2 , m.p. 212. 
 
 When cold nitric acid acts on resorcin and various gum resins 
 (galbanum, etc.), or by nitrating meta-nitro-phenol and various 
 dinitro-phenols, we get trinitro-resorcin (NO 2 ) 3 [2, 4, 6]C 6 H[i, 3](OH) 2 . 
 It melts at 175. Ferrous sulphate and lime water colour it green 
 (picric acid colours it blood-red). The diethyl ester melts at 120 
 (C. 1903, II. 829). It is reduced by tin and HC1 to triamino-resorcin 
 ethers. Stryphinic acid, like picfic acid, gives, with hydrocarbons like 
 naphthalin, phenanthrene, etc., and with amines, readily crystallising 
 molecular combinations (C. 1909, I. 526). 
 
 Tetranitro-resorcin (NO 2 ) 4 C 6 (OH) 2 , m.p. 152, on boiling with water, 
 yields trinitro-phloroglucin (C. 1908, I. 724). 
 
 Thio-resorcin C 6 H 4 [i, 3](SH) 2 , m.p. 27 and b.p. 243. It results 
 from the reduction of benzol-m-disulphonic chloride, and, when 
 heated with phenyl iso-cyanate, becomes bis-phenyl carbamate, C 6 H 4 
 (SCONHC 6 H 5 ) 2 , m.p. 179 (B. 29, R. 177 ; C. 1900, I. 252). 
 
 HOMOLOGOUS RESORCINS. Orcin is by far the most important 
 body among those which follow : 
 
 M.p. B.p. 
 
 Orcin .... CH 3 [i]C 6 H 3 [ 3 , 5 ](OH) 2 107 290 
 
 Cresorcin . . . CH 3 [i]C 6 H 8 [ 2 , 4 ](OH) 2 io 4 269 (6.19,136) 
 2, 6-Dioxy-toluol . . . CH 3 [i]C 6 H 3 [ 2 , 6](OH) 2 64 .. (B. 17, 1963) 
 3, 5-Dioxy-o-xylol . (CH 3 ) 2 [i, 2]C 6 H 2 [ 3 , 5 ](OH) 2 137 .. (A. 329, 305) 
 
 2, 4-Dioxy-m-xylol . (CH 3 ) 2 [i, 3 ]C 6 H 2 [2, 4 ](OH) 2 147 149 (B. 23, 3114) 
 m-Xylorcin . . (CH 3 ) 2 [i, 3]C 6 H 2 [ 4 , 6](OH) 2 125 277\ m 1Q _ T ^ 
 /9-Orcin . . . (CH 3 ) 2 [i, 4 ]C 6 H 2 [ 3 , 5] (OH), 163 279 f ( *' LV > 23 
 
 Mesorcin . .(CH 3 ) 3 [i, 3, 5]C 6 H[ 2 , 4 ](OH) 2 i 49 275 (A.215,ioo) 
 
 Di-tertiary-amyl-resorcin (C 5 H 11 ) 2 C 6 H 2 [i, 3 ](OH 2 89 .. (B. 25,2653). 
 
HOMOLOGOUS RESORCINS 217 
 
 Orcin CH 3 [i]C 6 H 3 [3, 5](OH) 2 ,(B. 15, 2995). It is found in many 
 lichens of the varieties Roccella and Lecanora, partly free and partly as 
 orsellic acid, or partly as erythrine or diorsellic erythric ester. It is 
 obtained from orsellic acid either by dry distillation or by boiling 
 with lime. 
 
 It is obtained by fusing the extract of aloes with caustic potash. 
 It can be prepared synthetically from 3, 5-dinitro-p-toluidin and various 
 other toluol derivatives by the replacement of their side groups by 
 hydroxyl groups (B. 15, 2990). 
 
 Orcin is produced in the distillation of o-dioxy-phenyl acetate of 
 silver (HO) 2 [3, 5]C 6 H 3 [i]CH 2 .CO 2 Ag (B. 19, 1451), and upon heating 
 dehydracetic acid (see Vol. I.) with concentrated caustic potash (B. 26, 
 R. 316). Orcin crystallises in colourless, six-sided prisms containing 
 one molecule of water. It dissolves easily in water, alcohol, and ether, 
 and has a sweet taste. It melts at 56, when it contains water, but 
 gradually loses this, and melts (dried in the desiccator) at 107. It boils 
 at 290. Lead acetate precipitates its aqueous solution ; ferric 
 chloride colours it a blue-violet. Bleaching lime causes a rapidly 
 disappearing dark- violet coloration. It yields azo-colouring sub- 
 stances with diazo-compounds, and therefore has the 2OH-groups in 
 the meta-position. It does not form a fluorescei'n with phthalic 
 anhydride. Chlorine changes it, when dissolved in glacial acetic acid, 
 into trichlororcin, melting at 127. Dissolved in chloroform it is con- 
 verted by the same reagent into pentachlororein, or [1, 3, 5]-diketo- 
 methyl-pentachloro-R-hexene (B. 26, 317). 
 
 Nitroso-orein CH 3 .C 6 H 2 (OH) 2 (NO) consists of two modifications 
 dark-red crystals and bright-yellow needles ; the first change to the 
 second when heated to ioo-no (B. 29, 989). 
 
 On allowing its ammoniacal solution to stand exposed to the air, 
 orcin changes to orcein C 2 ,H 24 N 2 O 7 (B. 23, R. 647), which separates 
 out in the form of a reddish-brown amorphous powder. It dissolves 
 in alcohol and alkalies with a dark-red colour, and is reprecipitated by 
 acids. Orcein forms red lac-dyes with metallic oxides. It is the chief 
 constituent of the colouring matter archil (called also persio, cudbear, 
 and purpur French), which originates from the same lichens as orcin 
 through the action of ammonia and air. Litmus is produced from the 
 lichens Roccella and Lecanora by the action of ammonia and potassium 
 carbonate. The concentrated blue solution of the potassium salt, 
 when mixed with chalk or gypsum, constitutes the commercial 
 litmus. 
 
 Iso-orcin (cresorcin, y-orcin) is obtained by fusing 2, 4-toluol- 
 disulphonic acid with KOH. Also from amido-o-cresol, etc. Also 
 from methylene-bis-resorcin (q.v.), resulting from the action of formalde- 
 hyde upon resorcin, by reduction with zinc dust and NaOH. By 
 repeating the formaldehyde condensation and by reduction of the 
 resulting methylene bis-cresorcin we obtain m-xylorcin (C. 1907, I. 547). 
 Similarly, 3, 5-dioxy-o-xylol and 1, 2, 6-trimethyl-3, 5-dioxy-benzol 
 have been obtained from orcin (A. 329, 305). 
 
 p-Xylorcin, or fi-orcin, from m-dinitro-p-xylol, rapidly acquires a red 
 colour on exposure to air containing ammonia. It has been obtained 
 by distillation from various lichen acids e.g. usnic acid. Mesorcin, or 
 dioxy-mesitylene, is made from dinitro-mesitylene. 
 
2i8 ORGANIC CHEMISTRY 
 
 HYDROQUINONE GROUP. 
 
 The p-dioxy-benzenes are usually called hydroquinones, because 
 they are easily obtained by the reduction of the p-quinones, and 
 just as readily reconverted into the latter by ferric chloride. 
 
 Hydroquinone, p-dioxy-benzene C 6 H 4 [i, 4](OH) 2 , melting at 169, 
 was first obtained by the dry distillation of quinic acid and by digesting 
 its aqueous solution with lead dioxide (Wohler, A. 65, 349) : 
 
 C 6 H 7 (OH) 4 COOH+0 = C 6 H 4 (OH) 2 + C0 2 + 3 H 2 0. 
 
 It results also, together with glucose, on boiling the glucoside 
 arbutin with dilute sulphuric acid, and occurs in Protect mellifera 
 (B. 29, R. 416). 
 
 It is further formed by the electrolytic oxidation of an alcoholic 
 benzene solution acidulated with sulphuric acid (B. 27, 1942), and by 
 fusing [i, 4]-iodo-phenol with potassium hydroxide at 180 ; or from 
 [2, 5]-oxy-salicyclic acid, and from para-amido-phenol ; also in small 
 quantities in the distillation of succinates. The most convenient 
 method of preparing it consists in reducing quinone with sulphurous 
 acid : 
 
 Extract the hydroquinone from the aqueous solution by shaking 
 with ether, and purify the product by recrystallisation from hot water 
 that has passed through animal charcoal (B. 19, 1467) and contains 
 sulphur dioxide. 
 
 Hydroquinone is dimorphous and crystallises in monoclinic flakes 
 and hexagonal prisms. It decomposes when quickly heated. It dis- 
 solves readily in water (in 17 parts at 15), alcohol, and ether. It forms 
 crystalline compounds with H 2 S and SO 2 ; these are decomposed by 
 water. Ammonia colours the aqueous solution reddish brown. It is 
 only in the presence of ammonia that lead acetate produces a precipitate 
 in the solution of hydroquinone. Oxidising agents (like ferric chloride 
 and chromic acid) convert hydroquinone into quinone ; quinhydrone 
 is an intermediate product. 
 
 Hydroquinone, like quinone, forms quinone-dioxime (B. 22, 1283) 
 with hydroxylamine. It does not combine with diazonium salts to 
 form azo-compounds, but it is oxidised by them to quinone (C. 1908, 
 II. 409). 
 
 Hydroquinone is used as a " developer " in photography, and in 
 therapeutics as an antifermentative and antipyretic agent. 
 
 Ethers. Hydroquinone-monomethyl ether CH 3 .O[4]C 6 H 4 [i]OH is 
 formed from methyl-arbutin ; and from hydroquinone by heating it 
 with caustic potash, and methyl iodide or potassium-methyl sulphate 
 (B. 14, 1989). It melts at 53 and boils at 247. The dimethyl ether 
 melts at 56 and boils at 205. The ethyl ether melts at 66 and boils 
 at 246. The diethyl ether melts at 71. Diphenyl ether, m.p. 77 
 (A. 350, 97). 
 
 Hydroquinone bis-chloro-phosphin C 6 H 4 (OPC1 2 ) 2 melts at 65 and 
 boils at 200 (65 mm.), while hydroquinone bis-oxy-chloro-phosphin 
 C 6 H 4 (OPOC1 2 ) 2 melts at 123 and boils at 270 (70 mm.) (B. 27, 
 2568). 
 
 Hydroquinone diacetate C 6 H 4 (O.COCH 3 ) 2 melts at 123, 
 
HYDROQUINONE GROUP 219 
 
 Hydroquinone dibenzoate C 6 H 4 (O.COC 6 H 5 ) 2 melts at 199. 
 
 Homologous hydroquinones are usually prepared by action of sul- 
 phur dioxide upon the homologous quinones. Tolu-hydroquinone re- 
 sults from the action of hot dilute sulphuric acid upon p-tolyl-hydroxyl- 
 amine and other p-alkyl phenyl-hydroxylamines, by atomic displace- 
 ment in the quinols first formed. The intermediate formation of tolu- 
 quinols is also the cause of the peculiar formation of tolu-hydroquinone 
 during the oxidation of p-cresol with potassium persulphate (B. 41, 
 299). 
 
 Hydro-p-xylo-quinone bears the name hydrophlorone. Dimethyl- 
 hydro-thymo-quinone, boiling at 249, occurs in the ethereal oil of Arnica 
 montana, also in " ayapana oil " of Eupatorium ayapana (B. 41, 509 ; 
 A. 170, 363). Ditertiary amyl-hydroqiiinone results from hydroquinone 
 and iso-amylene with glacial acetic acid and sulphuric acid (B. 25, 2650). 
 
 M.p. 
 
 Hydro-tolu-quinone (B. 15, 2981) (CH t )[i]C t U t [2, 5](OH), 124 (A. 215, 159) 
 
 Hydro-o-xylo-quinone . . (CH,),[i, 2]C,H,[3, 6](OH) t 121 (B. 18, 2673) 
 
 Hydro-m-xylo-quinone . . (CH,),[i, 3 ]C,H,[ 2 , s])OH) t 150 (B. 18, 1151) 
 
 Hydro-p-xylo-quinone . . (CH,),[i, 4]C.H,[ 2 , 5](OH) t 212 (A 215, 169) 
 
 Hydro-cumo -quinone . . (CH,),[i, 2, 4JC.H[3, 6](OH), 169 (B. 18, 1152) 
 
 Hydro-thymo-quinone . . (CH,)(C,H,)[i, 4]C.H 1 [2, 5] (OH) , 139, b.p. 290 
 
 Ditert. amylhydro-quinone . (CsH u ),C,Hj[i, 4](OH), 185 
 
 Substituted Hydroquinones. Monochloro- and monobromo-hydro- 
 quinones have been obtained by the action of concentrated hydro- 
 chloric or hydrobromic acid upon p-quinone (B. 12, 1504). Mono- 
 chloro-quinone gave dichloro-quinone, etc. (A. 210, 153). Di-, tri-, and 
 tetrachloro-hydroquinones result from the corresponding chlorinated 
 quinone by the action of SO 2 . 
 
 Monochloro-quinone melts at 104 ; Monobromo-quinone melts at 110 
 [2, 5]-Dichloro-quinone 166 ; [2, 5]-Dibromo-quinone 186 
 [2, 6] -Dichloro-quinone 158; [2, 6]-Dibromo-quinone 163 
 Trichloro-quinone ,, 134 ; Tribromo-quinone ,. 136 
 
 Tetrachloro-quinone ,, 232 ; Tetrabromo-quinone 244 
 
 Nitro-hydroquinone, m.p. 133, is formed in the action of ammonium 
 persulphate upon nitro-phenol (/. pr. Ch. 2, 48, 179). 
 
 [1, 3]-Dinitro- and [2, 6]-dinitro-diethyl-hydroquinone, m.p. 233 
 and 176 (A. 215, 149), result from the nitration of hydroquinone di- 
 ethylate and diacetate. They change into the same trinitro-diethyl- 
 hydroquinone, m.p. 130, and [2, 5]-dinitro-hydroquinone diacetate, 
 m.p. 96. The latter compound exchanges an NO 2 group very readily 
 for NH.C 6 H 5 (B. 24, 3824). 
 
 Dinitro-hydroquinone results from dinitro-arbutin and dinitro-hydro- 
 quinone diacetate. Reduction changes these compounds to amido- 
 hydroquinones (B. 22, 1656 ; 23, 1211). 1, 4-Diamido-hydroquinone 
 is obtained from the dioxime of 2, 5-dioxy-quinone. 
 
 When tetrachloro-quinone is digested with a diluted solution of 
 primary sodium sulphite (A. 114, 324), we get dichloro-hydroquinone- 
 disulphonic acid C 6 C1 8 \ ( u ^ j ts aqueous solution is coloured 
 
 ( (SO 3 H) 2 
 
 indigo-blue by ferric chloride. When its alkaline solution is boiled it 
 oxidises to potassium euthio-chronate. 
 
220 ORGANIC CHEMISTRY 
 
 Monothio-hydroquinone C 6 H 4 [i, 4](OH)(SH), m.p. 30 and b.p. 
 167 (45 mm.), results from p-diazo-phenol chloride and potassium 
 xanthogenate. p-Oxy-diphenyl sulphide C 6 H 5 S[i]C 6 H 4 [4]OH results 
 from heating benzol-sulphinic acid with phenol to 150 (C. 1904, 
 I. 130). 
 
 Dithio-hydroquinone CgH 4 [i, 4](SH) 2 , m.p. 98, is obtained from 
 p-benzol-disulphonic chloride or diazo-phenyl disulphide. In the air 
 it gradually oxidises to p-phenylene disulphide [C 6 H 4 S 2 ]*. Methyla- 
 tion converts it into p-phenylene-dimethyl sulphide C 6 H 4 (SOCH 3 ) 2 , 
 m.p. 188, which, on oxidation with HNO 3 , yields a disulphoxide 
 C 6 H 4 (SOCH 3 ) 2 , m.p. 188, and a disulphone C 6 H 4 (SO 2 CH 3 ) 2 , m.p. 260 
 (B. 42, 2721). 
 
 TRIHYDRIC PHENOLS. 
 
 The three isomeric trioxy-benzols are known in the compounds 
 pyrogallol, phloroglucin, and oxy-hydroquinone. 
 
 Among the methods of forming polyoxy-benzols we must mention 
 the hydrolysis of polyamido-benzols, which is useful for preparing 
 phloroglucins or sym. trioxy-benzols. 
 
 Pyrogallol, pyrogallic acid C 6 H 3 [i,2,3](OH) 3 , 'm.p. 132, is pro- 
 duced by the elimination of CO 2 from gallic acid or pyrogallo-carbo- 
 xylic acid CO 2 H[i]C 6 H 2 [3,4,5](OH) 3 , when heated alone, as was first 
 observed by Scheele (1786), or, better, with water to 210 ; also by 
 fusing the two p-chloro-phenol-disulphonic acids and haematoxylin with 
 potassium hydroxide. It forms white flakes or needles. It dissolves 
 readily in water, with more difficulty in alcohol and ether. Its alka- 
 line solution absorbs oxygen very energetically (B. 14, 2666), turns 
 brown, and decomposes into carbon dioxide, acetic acid, and brown 
 substances. It is used in ' gas analysis for the determination of 
 oxygen. Pyrogallol quickly reduces salts of mercury, silver, and 
 gold, with precipitation of the metals, while it is oxidised to acetic 
 and oxalic acids. 
 
 Ferrous sulphate containing ferric oxide colours its solution blue, 
 ferric chloride red. Lead acetate precipitates white C 6 H 6 O 3 .PbO. 
 An iodine solution imparts a purple-red colour to an aqueous or alco- 
 holic pyrogallol solution. Gallic and tannic acids react similarly. 
 Electrolytic dissociation produces purpuro-gallin (C. 1903, 1. 927 ; 1904, 
 I. 798, 1005). 
 
 1-Monomethyl ether, m.p. 40, b.p. 16 147. 2-Monomethyl ether, 
 m.p. 87, b.p. 24 155. 
 
 1, 3-Dimethyl ether is found in beechwood creosote. It melts at 
 5i-52 and boils at 252 (B. 11, 333 ; M. 19, 557). Also by partial 
 saponification of pyrogallol-trimethyl ether. It is notable that the 
 methoxyl, although occupying the middle position, is most easily 
 saponified (C. 1905, II. 1062). Different oxidising agents convert it 
 into ccerulignone, a diphenyl derivative. 
 
 1, 2-Dimethyl ether, b.p. 235 (C. 1904, II. 1118). 
 
 The trimethyl ether melts at 47 and boils at 235 (B. 21, 607, 
 
 2020). 
 
 The ethyl, diethyl, and triethyl ethers melt at 95, 79, and 39. The 
 syrupy dimethyl acetate yields a quinone, C 6 H 2 (OCH 3 ) 2 O 2 , with 
 chromic acid ; the triacetate crystallises. 
 
TRIHYDRIC PHENOLS 221 
 
 Pyrogallol carbonate OHC 6 H 3 <^>CO, m.p. 133, from pyrogallol 
 
 and phosgene in pyridin solution. Hot water regenerates the pyrogallol 
 (B. 37, 106). 
 
 Trichloro-pyrogallol C 6 C1 3 (OH) 3 melts with decomposition at 177 
 (B. 20, 2035). 
 
 4-Bromo-pyrogallol Br[4]C 6 H 2 [i,2,3](OH) 3 , m.p. 140 with decom- 
 position ; 4, 6-dibromo-pyrogallol Br 2 [4,6]C 6 H[i,2,3](OH) 3 , m.p. 158 
 with decomposition. These are formed by brominating the pyro- 
 gallol carboxylate. 
 
 Tribromo-pyrogallol C 6 Br 3 (OH) 3 , from pyrogallol and bromine, 
 when digested with bromine yields xanthogallol C 18 H 4 Br 14 O 6 , m.p. 
 
 122 (A. 245, 335). 
 
 4-Nitro- and 4, 6-dinitro-pyrogallol, m.p. 162 and 208, by nitro- 
 genation of pyrogallol carboxylate. By reduction we obtain the cor- 
 responding amido-compounds as easily oxidisable substances, which, 
 on boiling with water or dilute acids, become I, 2, 3, 4-tetra-oxy- and 
 penta-oxy-benzol respectively (B. 37, 114). 
 
 Methyl-pyrogallol-dimethyl ether CH 3 .C 6 H 2 (OH)(OCH 3 ) 2 , m.p. 36 
 and b.p. 265, occurs in beechwood creosote (B. 12, 1371). 1-Methyl- 
 [3, 4, 5]-pyrogallol-[4, 5]-dimethyl ether, irodol, m.p. 57 and b.p. 249, 
 is formed on distilling iridic acid CO 2 H.CH 2 .C 6 H 2 (OH)(OCH 3 ) 2 
 (B. 26, 2018). 
 
 Propyl-pyrogallol-dimethyl ether, picamar C 3 H 7 .C 6 H 2 (OH)(OCH 3 ) 2 , 
 b.p. 245, was discovered in beechwood creosote by Reichenbach 
 (B. 11, 329 ; A. 8, 224). 5-Amido-pyrogallol-trimethyl ether (CH 3 O) 
 C 8 H 2 NH 2 , m.p. 114, from trim ethyl-gallic amide (A. 340, 224). 
 
 Phloroglucin C 6 H 3 [i,3, 5](OH) 3 melts at 219 when it is rapidly 
 heated. Hlasiwetz first obtained it (1855) in the decomposition of 
 phloretin (q.v.). It can also be prepared from qiiercetin, hesperidin, and 
 other glucosides (q.v.). It is formed from different resins (catechu, kino, 
 gamboge, dragon's blood, and others), on fusion with caustic potash. 
 It is most easily made by fusing resorcin with caustic soda (B. 14, 954 ; 
 18, 1323) ; by the fusion of orcin and benzol-trisulphonic acid with 
 sodium hydroxide ; also by the saponification and decomposition of 
 synthetically prepared phloroglucin-tricarboxylic ester, which gives 
 up 2 CO 2 (B. 18, 3454). It is best formed from sym. triamido-benzol, 
 which is not isolated, but hydrolysed by boiling the solution of the 
 double tin-salt obtained direct from trinitro-benzol. 
 
 In the same way homologous phloroglucins have been obtained : 
 mono-, di-, and trimethyl-phloroglucm C 6 H 2 (CH 3 )(OH) 3 , C 6 H(CH 3 ) 2 
 (OH) 3 , C 6 (CH 3 ) 3 OH 3 , which melt at 215, 163, and 184 respectively 
 (C. 1898, II. 537 ; 1900, I. 600). 
 
 It crystallises in large, colourless prisms with 2H 2 O ; these 
 effloresce in the air. It loses all its water of crystallisation at 
 110, melts at 218, and sublimes without decomposition. It has 
 a sweetish taste, and dissolves readily in water, alcohol, and ether. 
 Lead acetate precipitates it ; ferric chloride colours its solution a 
 dark violet. 
 
 Chlorine oxidises phloroglucin to dichloracetic acid and tetrachlor- 
 acetone. One of the first intermediate products is hexachloro-triketo- 
 R-hexylene. For the action of bromine, see B. 23, 1706. It is con- 
 
222 ORGANIC CHEMISTRY 
 
 verted by reduction into phloroglucite or sym. trioxy-hexamethylene 
 (B. 27, 357). 
 
 Phloroglucin, in most of its reactions for example, with phenyl 
 cyanate (see B. 23, 269), conducts itself like a trihydric phenol 
 C 6 H 3 (OH) 3 ; on the other hand, it unites with three molecules of hydro- 
 xylamine to form a trioxime (see below), hence it may be considered a 
 triketone [i, 3, 5]-triketo-hexamethylene (B. 19, 159). 
 
 Trioxy benzol Triketo-hexamethylene. 
 
 In order to explain the trioxime formation it might be assumed 
 that the [i, 3, 5]-trioxy-benzo-formula is the unstable pseudo-form of 
 phloroglucin. 
 
 In the keto-form, phloroglucin also reacts in the methylation, with 
 methyl iodide and alkali, which finally leads to hexamethyl-phloro- 
 glucin or hexamethyl-triketo-hexamethylene C 6 (CH 3 ) 6 O 3 , m.p. 80, b.p. 
 248, also formed by methylation of the homologous methyl-phloro- 
 glucins, and split up by fuming HC1 into di-iso-propyl-ketone and iso- 
 butyric acid (B. 23, R. 462 ; C. 1899, II. 760). A peculiar phenomenon 
 is the condensation of phloroglucin and its homologues with salicyl 
 aldehyde tofluorones (q.v.), a reaction in which part of the phloroglucin 
 molecule acts in the keto-form, and another part in the hydroxyl form 
 (M. 21, 62). 
 
 Phloroglucin easily combines with formaldehyde to form methylene- 
 bis-phloroglucin CH 2 [C 6 H 2 (OH) 3 ] 2 , a diphenyl-methane derivative, 
 which, on reduction with zinc dust and NaHO, decomposes into phloro- 
 glucin and methyl-phloroglucin, as well as a little dimethyl- and tri- 
 methyl-phloroglucin (A. 329, 269). This has a close connection with 
 Filix acid from Aspidium filix-mas, which, on reduction with zinc 
 dust and NaHO, yields, besides mono-, di-, and trimethyl-phloroglucin, 
 also butyryl-filicinic acid. On prolonged action the latter is split up 
 into n-butyric acid and filicinic acid, probably represented by gem-di- 
 
 methyl-dioxy-dihydro-keto-benzol CH^ OH R : (A> 307 ' 249 ' 318 ' 
 230). 
 
 Phloroglucin trioxime C 6 H 6 (NOH) 3 , a crystalline powder exploding 
 at 155. Phenyl-hydrazin attaches itself to phloroglucin much as it 
 does to oxalic ester and dioxy-succinic ester. 
 
 Trinitroso-phlorogluein C 6 (NO) 3 (OH) 3 (B. 11, 1375) and trinitro- 
 phloroglucin C 6 (NO 2 ) 3 (OH) 3 yield on reduction triamido-phloroglucin 
 C 6 (NH 2 ) 3 (OH) 3 , which, on boiling with MnO 2 and soda, yields croconic 
 acid (B. 26, 2185). 
 
 Phloroglucin ethers result from treating phloroglucins with alco- 
 hols and HC1, or from methylation with diazo-methane or dimethyl 
 sulphate in etheric solution (C. 1906, II. 1836). Monomethyl ether, 
 m -P- 75-78, b.p. 16 213, gives a mononitroso-derivative, which may 
 be converted into oxy-methoxy-p-quinone (C. 1903, I. 285), and a di- 
 nitroso-derivative, which, on reduction, yields diamido-dioxy-anisol. 
 
 Dimethyl ether, m.p. 37, b.p. 17 i72-i75, forms with N 2 O 3 an o- as 
 well as a p-nitroso-derivative, 3, $-dimethoxy-quinone oxime, red flakes, 
 and 3, 5-dimethoxy-quinone oxime, yellow needles (M. 21, 15). Tri- 
 
TRIHYDRIC PHENOLS 223 
 
 methyl ether, m.p. 52, b.p. 255, also obtained by splitting up methyl- 
 dihydro-cotoi'n with potash. 
 
 Triphenyl ether C 6 H 3 (OC 6 H 5 ) 3 , m.p. 112, by heating sym. tri- 
 bromo-benzol with K phenate in the presence of Cu bronze (A. 350, 
 102). On chlorination products of phloroglucin ether, see C. 1902, 
 II. 739. Phlorogluein triacetate, m.p. 105. Trithio-phloroglucin 
 C 6 H 3 (SH) 3 , m.p. 58. Triacetate, m.p. 74. Trimethyl ether, m.p. 68 
 (B. 42, 3252). 
 
 Oxy-hydroquinones result from the reduction of oxy-quinones. 
 
 Oxy-hydroquinone C 6 H 3 [i, 2, 4](OH) 3 is produced on fusing hydro- 
 quinone with KOH (together with tetra- and hexa-oxy-diphenyl (B. 
 18, R. 24). It is crystalline, very soluble in water and ether, and in 
 aqueous solution soon acquires a dark colour. It melts at 140-5. 
 Ferric chloride colours it a dark greenish brown. Its triethyl ether 
 C 6 H 3 (O.C 2 H 5 ) 3 is obtained from trioxy-ethyl-benzoic acid (from aescule- 
 tin). It can also be prepared by ethylating ethoxy-hydroquinone. 
 It melts at 34 (B. 20, 1133). The trimethyl ether C 6 H 3 (O.CH 3 ) 3 , from 
 methoxy-quinone, boils at 247. A better method of producing oxy- 
 hydroquinone is from its triacetate, m.p. 97 (A. 311, 341 ; C. 1899, I. 
 1094) : 
 
 C 6 H 4 O 2 +2(CH 3 CO) 2 O = C 6 H 3 (OCOCH 3 ) 3 +CH 3 COOH. 
 
 Sodium amalgam reduces it to dihydro-resorcin. 
 
 Nitro- and halogen oxy-hydroquinones, see B. 34, 2837. Hydro- 
 quinone monomercaptan C 6 H 3 (OH) 2 SH, m.p. 120, is obtained by 
 splitting up hydroquinone-thio-sulphonic acid C 6 H 3 (OH) 2 S.SO 3 H and 
 analogous sulphuretted hydroquinone derivatives, prepared by the 
 action of sodium thio-sulphate and other thio-acids upon benzo-quinone. 
 Iodine oxidises it to hydroquinone disulphide [C 6 H 3 (OH) 2 ] 2 S 2 , m.p. 
 183 (C. 1906, II. 1467). 
 
 TETRAHYDRIC PHENOLS. 
 
 There are three possible isomerides : (i) Apionol, v-tetraoxy- 
 benzol [phenetetrot] C 6 H 2 [i, 2,3,4] (OH) 4 , needles, m.p. l6l > by boiling 
 amido-pyrogallol chlorohydrate in water. Dimethyl-apionol C 6 H 2 
 [i, 2, 3, 4](O.CH 3 ) 2 (OH) 2 , by heating apiolic acid with caustic potash. 
 It melts at 106 and boils at 298. Tetramethyl-apionol C 6 H 2 (O.CH 3 ) 4 
 melts at 81. 
 
 [1, 2] - Methylene - 3, 4 - dimethyl - apionol C 6 H 2 (O 2 : CH 2 )(O.CH 3 ) 2 , 
 apione, is formed when apiolic acid is heated with dilute sulphuric 
 acid. It melts at 69 (B. 24, 2608 ; 29, 1806). 
 
 l-n-Propyl-2, 3, 4, 5-tetraoxy-benzol is obtained as methylene- 
 dimethyl ether, dihydro-apiol, melting at 25 and boiling at 292, in the 
 reduction of isapiol. 
 
 (2) Unsym. tetraoxy-benzol C 6 H 2 [i,2,3, 5](OH) 4 is an amorphous, 
 glassy mass obtained from iretol by the action of hydrochloric acid 
 at 150. The 1, 3-dimethyl ether is prepared by reducing i, 3-dimeth- 
 oxy-2, 5-quinone. It melts at 158. The tetramethyl ether melts at - 
 47 and boils at 271 (B. 23, 2291). 
 
 Iretol CH 3 O.C 6 H 2 (OH) 3 melting at 186, is one of its monomethyl 
 ethers. It is formed together with iridic acid on fusing irigenin with 
 potash (B. 26, 2015). 
 
224 ORGANIC CHEMISTRY 
 
 (3) Sym. tetraoxy-benzol C 6 H 2 [i, 2, 4, 5](OH) 4 is obtained by 
 reducing i, 4-dioxy-2, 5-quinone with stannous chloride. It melts 
 at 2I5-220. Its tetra-acetyl ester melts at 217 (B. 21, 3374). 
 
 Dichloro-tetraoxy-benzol, hydro-chloranilic acid C 6 C1 2 (OH) 4 results 
 in the reduction of chloranilic acid with sulphurous acid (A. 146, 32). 
 
 Amido-s-tetraoxy-benzol results from the action of stannous 
 chloride upon nitro-dioxy-quinone, and also Nitro-amido-s-tetraoxy- 
 benzol and diamido-s-tetraoxy-benzol (B. 18, 502), by the reduction 
 of nitranilic acid. Croconic acid and ammonia are produced on boil- 
 ing the diamido-body with potash ; oxidising agents convert it into 
 diamido-dioxy-quinone. 
 
 Hydro-euthiochronic alkali salts, see Euthiochronic acid, below. 
 
 Pentahydric Phenols. Pentaoxy-benzol C 6 (OH) 5 H, colourless crys- 
 tals, from diamido-pyrogallol on boiling in water (B. 37, 122). Penta- 
 acetate, m.p. 165. Its diethyl ether, see C. 1903, II. 829. 
 
 Hexahydric Phenols. In describing the benzene ring formations 
 mention was made of the remarkable isolation of potassium hexaoxy- 
 benzene or potassium-carbon monoxide (discovered by Liebig in 
 1834), which results upon conducting carbon monoxide over 
 heated potassium (confirmed by Nietzki and Benkiser in 1885). 
 Dilute hydrochloric acid, acting upon the fresh mass, yields 
 hexaoxy-benzene. 
 
 Hexaoxy-benzene C 6 (OH) 6 is obtained from triquinoyl by reduction 
 with stannous chloride and hydrochloric acid. It separates in the form 
 of small, grayish-white needles, which acquire a reddish-violet colour 
 on exposure to the air. They are not fusible, but decompose at about 
 200. Concentrated nitric acid oxidises it to triquinoyl. 
 
 It forms the hexacetyl derivative C 6 (O.C 2 H 3 O) 6 when heated with 
 acetic acid and sodium acetate. It is a crystalline mass, melting at 
 203 (B. 18, 506). 
 
 8. Quinones. 
 
 This is the designation ascribed to all derivatives of benzene in which 
 2H-atoms are replaced by 2O-atoms. The replacement is either in the 
 o- or the p-position. We distinguish ortho-quinones and para-quinones. 
 The latter are especially characteristic of the mono-nucleus aromatic 
 hydrocarbons. Metaquinones are not known. 
 
 Constitution. The constitution of the quinones of the aromatic 
 hydrocarbons having one nucleus is not fully established. They are 
 considered either as benzene derivatives, the oxygen atoms being as- 
 sumed to be linked to one another, or as p-dihydro-benzol derivatives, 
 containing two ketone groups. 
 
 The first view compares the quinones to peroxides ; they are indeed 
 powerful oxidising agents. Upon reduction they do not become the 
 p-diglycols of the p-dihydro-benzols, but p-dioxy-benzols, which are 
 true benzene derivatives. The p-quinones yield hydroquinones, and 
 the o-quinones the pyrocatechins. Further, each oxygen atom, by 
 the action of PC1 5 , is replaced by one chlorine atom. In opposition to 
 the peroxide formula of the para-quinones we have the p-diketone 
 formula, in support of which we can bring forward the formation of a 
 monoxime and a dioxime, as well as the absorption of 2Br and 4Br by 
 para-quinone (/. pr. Ch. 2, 42, 61 ; B. 23, 3141). Nitroso-phenol is 
 
QUINONES 225 
 
 considered by most chemists to be quinone monoxime. The various 
 formulas for o- and p-quinone are : 
 
 -O CH CO CH 
 
 HC CH HC CO 
 
 II II II 
 
 HC CH HC CO 
 
 CO CH 
 
 Peroxide formula for p- and o-quinone. Diketone formula for p- 
 
 and o-quinone. 
 
 At the present time the diketone formula is generally preferred. 
 
 Ortho-quinones. The ortho-quinones are much less stable than the 
 para-quinones. The isolation of the simplest o-quinone has only been 
 successfully accomplished quite recently (Willstatter, 1904). Chloro- 
 and bromo-substitution products of o-quinone have been, on the other 
 hand, known for some time (Zincke). 
 
 o-Benzo-quinone C 6 H 4 [i, 2]O 2 is formed by gentle oxidation of pyro- 
 catechin with silver oxide in etheric solution (B. 37, 4744). It exists 
 in two isomeric forms (B. 41, 2580). When freshly prepared, it forms 
 colourless prisms, which shortly change into the more stable form of 
 bright-red plates, which melt with decomposition at 6o-7O. Chemi- 
 cally, both forms are perfectly equal. They are strong oxidisers, and 
 liberate iodine from acidulated KI solution ; on reduction with sul- 
 phurous acid they yield pyrocatechin. The two isomers perhaps cor- 
 respond to the above peroxide and diketone formulae. The o-benzol- 
 quinone, in contrast with p-quinone, is odourless and not volatile ; 
 in this respect it more closely resembles the o-quinones of the hydro- 
 carbons with condensed ring systems ; cp. naphtho-quinone and phen- 
 anthrene-quinone. 
 
 1, 2-Dimethyl-4, 5-benzo-quinone (CH 3 ) 2 [i, 2]C 6 H 2 [4, 5]O 2 , long red 
 needles, m.p. 102, by oxidation of 5-oxy-4-amido-i, 2-dimethyl-benzol 
 with potassium bichromate and sulphuric acid. Tetraehloro-o-benzo- 
 quinone C 6 Cl 4 [i, 2]O 2 , m.p. 131, and tetrabromo-o-benzo-quinone 
 C 6 Br 4 [i, 2]O 2 , m.p. 195, are formed by the action of chlorine 
 and bromine upon pyrocatechin dissolved in glacial acetic acid 
 (Zincke, B. 20, 1776). Tetrachloro-benzo-quinone, with aniline, trans- 
 poses itself into dianilino-dichloro-o-benzo-quinone C 6 C1 2 (NHC 6 H 5 ) 2 O 2 , 
 which on further action of aniline passes into dianilino-monochloro- 
 quinone-anile C 6 HC1(NHC6H 5 ) 2 ( : O)(: NC 6 H 5 ), m.p. 180. This is prob- 
 ably a derivative of p-quinone, since reduction with sulphurous acid 
 changes it to dianilino-p-quinone-anile (B. 38, 4103). The halogen- 
 substituted o-benzo-quinones show a great tendency to form addition 
 products with the most varied classes of bodies. Thus, the tetrabromo- 
 o-benzo-quinone forms with methyl alcohol a very stable combination 
 (C 6 Br 4 O 2 ) 2 CH 3 OH, m.p. 261, which can be acetylated (B. 36, 454). 
 
 Homologous chlorinated ortho-quinones are formed by the action 
 of chlorine upon the corresponding ortho-diamine chlorohydrates. 
 The o-diketo-chlorides first formed may be reduced to chlorinated 
 o-dioxy-benzols, which then give the chlorinated o-quinones by oxida- 
 tion (B. 27, 560). 
 
 Ortho-benzo-quinone, and several of its homologues, have been 
 
 VOL. II. Q 
 
226 ORGANIC CHEMISTRY 
 
 obtained in the form of dioximes by reduction of the corresponding 
 o-dinitroso-benzols ; o-nitroso-phenol should be regarded as a mon- 
 oxime of o-benzo-quinone. 
 
 PARA-QUINONES. 
 
 Benzo-quinone C 6 H 4 O 2 , m.p. 116, was first obtained in 1838 by 
 Woskresensky upon oxidising quinic acid, a hexahydro-tetraoxy- 
 benzoic acid, with manganese peroxide and sulphuric acid. Woskre- 
 sensky named the new body quinoyl, while Berzelius (Berz. Jahresb. 
 19, 407) proposed the name quinone. 
 
 Quinone results from the electrolytic oxidation of benzene (C. 1901, 
 I. 348) or from oxidation with silver peroxide (B. 38, 3964) ; but most 
 easily from hydroquinone or p-dioxy-benzol by the action of ferric 
 chloride, and from many p-di-derivatives of benzene by oxidation, 
 mostly with potassium bichromate and sulphuric acid ; thus, from 
 p-phenylene-diamine, sulphanilic acid, p-amido-azo-benzene, p-amido- 
 phenol, p-phenol-sulphonic acid, p-diamido-diphenyl, or benzidin. 
 It is usually prepared by oxidising aniline with sodium bichromate and 
 sulphuric acid (Nietzki, B. 20, 2283), in which process a black dye, ani- 
 line black, is formed as an intermediate product (B. 42, 2147). It has 
 also been obtained by oxidising quinite (q.v.). 
 
 Quinone crystallises in golden-yellow prisms. It possesses a peculiar, 
 penetrating odour. It is poisonous and attacks the skin. It distils 
 readily with steam, and dissolves easily in hot water, alcohol, and ether. 
 It turns brown on exposure to sunlight. In the presence of the latter 
 it combines to dioxy-benzo-phenones with benzaldehyde, and to dioxy- 
 aceto-phenone with acetaldehyde (B. 31, 1214). 
 
 From acidulated KI solution quinone separates iodine, and this 
 circumstance may be used for the volumetric estimation of quinone 
 solutions (C. 1899, II. 906 ; B. 43, 1171). 
 
 Reducing agents (SO 2 , Zn, and HC1) convert it first into quinhydrone, 
 an addition product of quinone and hydroquinone, which nascent 
 hydrogen changes into hydroquinone. 
 
 Hydrogen, in the presence of finely divided nickel, also reduces 
 quinone to hydroquinone at i8o-i90 ; while at lower temperatures 
 a further set of six H atoms is embodied and I, 4-cyclohexane-diol is 
 formed (C. 1908, I. 1458). 
 
 Concentrated nitric acid dissolves it in the cold, but when the acid 
 is hot it is decomposed, oxalic and prussic acids being formed. Silver 
 peroxide splits it up into maleic acid and CO 2 (B. 39, 3715). Bromine 
 converts quinone into quinone di- and tetrabromides, melting at 80 
 and at I7O-I75. p-Diketo-hexamethylene, the hydride corresponding 
 to quinone tetrabromide, has been obtained by starting with succino- 
 succinic ester. With acetic anhydride and concentrated sulphuric 
 acid it combines to form the triacetate of oxy-hydroquinone. 
 
 Phosphorus pentachloride converts quinone into p-dichloro-benzene ; 
 hydroxylamine chloride changes it to quinone oxime or nitroso-phenol, 
 and quinone dioxime. Phenyl-hydrazin reduces it to hydroquinone ; 
 a-alkyl-phenyl-hydrazins show a similar reducing power, changing 
 simultaneously with tetrazones. Nitro- and a-acidyl-phenyl-hydrazins, 
 on the other hand, yield monohydrazins of the quinones. 
 
 The nuclear H atoms of quinones are relatively easy to replace. 
 
PHENOL ADDITION PRODUCTS OF QUINONE 227 
 
 Substitution takes place with or without reduction to hydroquinone. 
 With HCN dicyano-hydroquinone is formed, C 6 H 2 [i, 4](OH) 2 [2, 3](CN) 2 . 
 With benzol-sulphinic acid quinone combines to form dioxy-diphenyl- 
 sulphone C 6 H 5 SO 2 C 6 H 3 (OH) 2 (a general reaction of quinoid sub- 
 stances). Thio-acids of the general formula RSH (where R denotes 
 an acid radicle), like thio-sulphuric acid, monothio-carboxylic acids, 
 xanthogenic acids, sulpho-cyanic acid, unite with quinone to sul- 
 phuretted derivatives of oxy - hydroquinone : C 6 H 3 (OH) 2 S.SO 3 H, 
 C 6 H 3 (OH) 2 S.COC 6 H 5 , C 6 H 3 (OH) 2 S.CS.OC 2 H 5 , etc. (C. 1906, II. 1466). 
 With benzo-hydrolene (q.v.), water is liberated and compounds like 
 C 6 H 2 O 2 [CH(C 6 H 5 )2] 2 are formed, belonging to the polynuclear aromatic 
 substances (B. 32, 2146). With aniline, quinone gives dianilido-quinone 
 dianile. With pyridin and quinolin salts, quinone gives addition pro- 
 ducts (C. 1903, I. 1408). With some metal haloids, it forms addition 
 products of a dark colour (B. 41, 2568). With halogen hydride, mono- 
 and dihalogen hydroquinone are formed (A. 336, 108). On boiling 
 with primary alcohols and adding zinc chloride, quinone forms dialk- 
 oxy-quinone (B. 34, 3993). 
 
 On the condensation of quinones with aceto-acetic ester to form 
 cumarone derivatives, see the latter. On the addition of diazo- 
 methane to quinone, see B. 32, 2292. 
 
 PHENOL ADDITION PRODUCTS OF QUINONE (A. 215, 134). 
 
 Of the addition products of quinone, those with mono- and dihydric 
 phenols are the most important. In general, quinone unites with two 
 molecules of a monohydric, and with one molecule of a dihydric phenol. 
 But there are exceptions (B. 42, 1149). These phenol addition pro- 
 ducts of quinone are distinguished by their intense coloration, and by 
 the ease with which they break up into their components on solution. 
 
 Pheno-quinone C 6 H 4 O 2 .2C 6 H5OH, m.p. 71, by addition of quinone 
 and phenol. It is easily volatilised, crystallises in red needles, and is 
 coloured blue by potash lye, and green by baryta water. Addition 
 products with homologous phenols, see C. 1898, 1. 887. On heating the 
 phenols with quinone, with or without H 2 SO 4 , colourless compounds 
 are formed without evolving water. They differ from pheno-quinone, 
 and must be regarded as probably hydroxylated diphenyl ethers, e.g. 
 OHC 6 H 4 OC 6 H 3 (OH) 2 from resorcin and quinone (B. 30, 2563 ; C. 1898, 
 
 II. 156). 
 
 Thio-pheno-quinone C 6 H 4 O 2 .2C 6 H 5 SH is formed similarly from 
 quinone and thio-phenol. It forms crystals of a dark-bronze colour, 
 colouring blue with NaHO. Gentle oxidation converts it into 3, 6- 
 diphenyl-thio-quinone (C 6 H 5 S) 2 [3, 6]C 6 H 2 [i, 4]O 2 , m.p. 257, which 
 is easily reduced to 3, 6-diphenyl-hydroquinone. On acetylation of 
 thio-pheno-quinone, hydroquinone diacetate is formed, with splitting 
 of the molecule (A. 336, 85). Compounds resembling thio-pheno- 
 quinone are also formed from quinone with aliphatic mercaptans. 
 
 Quinhydrone C 6 H 4 O 2 .C 6 H 4 (OH) 2 . This is produced by the direct 
 union of quinone with hydroquinone. It appears as an intermediate 
 product in the reduction of quinone or in the oxidation of hydroquinone 
 e.g. in electrolysis (B. 29, R. 1122), and is changed by continued 
 oxidation into quinone, and by reduction into hydroquinone. It con- 
 
228 ORGANIC CHEMISTRY 
 
 sists of green prisms or leaflets with metallic lustre, has a quinone-like 
 odour, melts readily, and dissolves in hot water with a brown, in alcohol 
 and ether with a green, colour. When it is boiled with water it decom- 
 poses into hydroquinone and quinone. The constitution of these com- 
 pounds probably corresponds to the following formulas (B. 28, 1615 ; 
 29, R. 903 ; A. 336, 90), in which the two bodies appear either as hemi- 
 acetal compounds, or as derivatives of dioxy-p-diketo-hexamethylene : 
 
 HO C OC 6 H 5 CO 
 
 TT/~* /~*TJ ^ / 6 5 \/"* y^TT 
 
 -LAV^ k^XT -|--|- /\-s V_>ii2 
 
 Pheno-quinone || || or | | /T T 
 
 HC CH H 2 C C< 
 
 V 'x/XOCeH, 
 
 C 6 H 6 C OH CO 
 
 Quinhydrone C 6 H 4 < 
 
 [i]O C OH 
 
 /\ 
 HC CH 
 
 II II 
 HC CH 
 
 v 
 
 [ 4 ]O C OH 
 
 or C 6 H 4 
 
 H 2 C CO 
 
 i I 
 
 [ 4 ]0-CH 
 
 Neither formula, however, explains the intense colour or the easy 
 dissociation of these products. There is therefore, of late, a tendency 
 to regard the pheno-quinones and quinhydrones as loose molecular 
 compounds, whose structure cannot be numerically expressed by changes 
 of valency (B. 41, 1463 ; /. pr. Ch. 2, 79, 418). On an interpretation 
 of quinhydrones as oxonium compounds, see B. 43, 3603. 
 
 Homologous p-Quinones. They are produced (i) by the oxidation 
 of the corresponding p-dioxy-benzenes or hydroquinones (even with 
 ferric chloride), of the corresponding p-diamines, p-amido-phenols, such 
 as amido-thymol and many other di-substitution products belonging to 
 the p-series, with ferric chloride, chromic acid, and manganese dioxide 
 and sulphuric acid. (2) Even mono-substituted alkyl-benzenes yield 
 p-quinones, especially when they are oxidised with chromic acid. This 
 is particularly true of amido- and oxy-alkyl-benzenes or alkyl-phenols. 
 Thus, o-toluidin yields tolu-quinone, while thymol and carvacrol yield 
 thymo-quinone or thy moil. Frequently an alkyl group will be dis- 
 placed, favouring the p-quinone formation, and be replaced by oxygen 
 e.g. in the oxidation of amido-mesitylene (B. 18, 1150) to m-xylo- 
 quinone, and of pseudo-cumidin to p-xylo-quinone. (3) p-Xylo- 
 quinone and duro-quinone have been synthesised by the action of 
 caustic potash upon the aliphatic a-diketones diacetyl- and acetyl-pro- 
 pionyl. In this reaction quinogens are first produced ; afterwards 
 follow the p-quinones : 
 
 CH 3 .CO.CO.CH 3 CH 3 .C(OH).CO.CH 3 CH 3 .C CO.CH 
 
 CH 3 CO.CO.CH 3 CH 2 CO.CO.CH 3 CH.CO.C.CH 3 
 
 Diacetyl Dimethyl-quinogen p-Xylo-quinone. 
 
 p-Xylo-quinone or phlorone occurs in the tar of beech wood. 
 
 Properties. The homologous p-quinones are very similar to their 
 prototype, benzo-quinone. They are also yellow-coloured, possess an 
 odour similar to that of quinone, sublime readily, and behave chemi- 
 
QUINONE HALOIDS 229 
 
 cally like p-benzo-quinone. They form quinhydrones, are easily 
 reduced by sulphurous acid to p-hydroquinones, and combine to 
 nitroso-phenols and quinone dioximes with hydroxylamine : 
 
 Tolu-quinone 
 o-Xylo-quinone . 
 m-Xylo-quinone . 
 p-Xylo-quinone . 
 o-Ethyl-benzo-quinone . 
 
 Pseudo-cumo-quinon e 
 
 Duro-quinone . 
 
 Thymo-quinone . 
 
 CH,[i]C.H,[2, 5]O, m p. 67 
 55 
 102 
 123 
 
 , 2]C.H,[ 3 , 6]0 2 
 , 3 ]C.H,[2, 5 ]0, 
 i, 4]C.H 1 [2, 5 ]0 2 
 (C.H s )[2]C.H,[i, 4 ]0 2 
 ),[i, 2, 4 ]C.H[ 3 , 6]0 2 
 i, 2, 4, 5]C,[ 3) 6]0, 
 (CH,)(C s H 7 )[i, 4 ]C.H,[2, 5 ]0, 
 
 38 (B. 28, R. 74i) 
 11 (B. 27, 1430) 
 ni (B. 29, 2171 ; 42, 4161) 
 45, b.p. 232. 
 
 When an ethereal solution of thymo-quinone is allowed to stand 
 in sunlight for some time, polythymo-quinone, m.p. 200, separates 
 (B. 18, 3195). See B. 29, 2176, for diduro-quinone. 
 
 QUINONE HALOIDS are obtained by the substitution of quinones 
 or by the oxidation of substituted hydroquinones. 
 
 A mixture of tri- and tetrachloro-quinone, called chlomnile, consists 
 of bright-yellow flakes. It is obtained from many benzene compounds 
 (aniline, phenol, isatin) by the action of chlorine or potassium chlorate 
 and hydrochloric acid (B. 29, R. 236). It oxidises, and serves as an 
 oxidising agent in the manufacture of colouring matters. 
 
 Trichloro- and tetrachloro-quinone are separated from one another 
 by the insolubility of the latter in water. The chloro-quinones are 
 obtained from chloro-hydroquinones by oxidation with nitric acid 
 (A. 146, 9 ; 210, 45 ; 234, 14) : 
 
 Monochloro-quinone m.p. 57' 
 [2, 5]-Dichloro-quinone i59 c 
 [2, 6]-Diehloro-quinone 120 
 
 Trichloro-quinone ,, 166 
 
 Monobromo-quinone m.p. 55' 
 [2, 5]-Dibromo-quinone i88 c 
 [2, 6]-Dibromo-quinone 122* 
 
 Tribromo-quinone 147* 
 
 Tetrachloro-quinone Tetrabromo-quinone 
 
 Dibromo-di-iodo-quinone m.p. 225 (B. 38, 555). 
 
 PC1 5 converts tetrachloro-quinone into phosphorus-containing deri- 
 vatives C 6 C1 5 .OPOC1 2 (?), and then into hexachloro-benzol (B. 24, 927). 
 It absorbs two atoms of chlorine and becomes hexachloro-p-diketo-R- 
 hexene, which caustic soda resolves into dichloro-maleic acid and 
 trichloro-ethylene. Potassium hydroxide converts trichloro-quinone 
 and tetrachloro-quinone into potassium chloranilate, and tribromo- and 
 tetrabromo-quinone into potassium bromanilate (see B. 32, 1005). 
 
 Amido-quinones. Amido-quinone is obtained in the form of its 
 aceto-compound C 6 H 3 O 2 (NHCOCH 3 ), m.p. 142, by oxidation of 
 
 1, 3, 4-diacetamido-phenol, while the I, 4, 5-diacetamido-phenol yields 
 
 2, 5-diamido-quinone C 6 H 2 O 2 [2, 5](NH 2 ) 2 (B. 30, 2096 ; 31, 2399). 
 
 Chloranile-amide C 6 C1 2 (NH 2 ) 2 O 2 is obtained from chloranilic acid. 
 Aniline, acting upon a hot alcoholic solution of quinone, produces not 
 only hydroquinone, but also dianilido-quinone, dianilido-quinone-anile, 
 and -dianile, as well as 2, 5-dioxy-i, 4-quinone (see below). 
 
 Quinone-monosulphonic acid C 6 H 3 O 2 (SO 3 H), in yellow prisms, is 
 formed by the oxidation of hydroquinone-sulphonic acid and of the 
 two p-amido-phenol-sulphonic acids with PbO 2 in sulphuric acid solu- 
 tion. The ammonium salt, golden plates, decomposes at i9O-i95 
 (/. pr. Ch. 2, 69, 334). 
 
230 ORGANIC CHEMISTRY 
 
 OXY-QUINONES AND POLYQUINOYLS. 
 
 Benzene Oxy-quinones. Methoxy-quinone CH 3 O[2]C 6 H 3 : O 2 , melt- 
 ing at 140, is produced by oxidising o-amido-anisol C 6 H 4 (NH 2 ).O.CH 3 
 with chromic acid. 
 
 Chloranilamic acid C 6 C1 2 (NH 2 )(OH)O 2 is obtained from chloranile. 
 
 2, 6-Dimethoxy-quinone (CH 3 O) 2 [2, 6]C 6 H 2 O 2 , melting at 249, 
 results from the oxidation of trimethyl-pyrogallol and trimethyl-phloro- 
 glucin (B. 26, 784). 
 
 2, 5-Dioxy-quinone (HO) 2 [2, 5]C 6 H 2 O 2 is obtained from dioxy- 
 quinone-dicarboxylic acid by boiling with hydrochloric acid, by the 
 oxidation of diamido-resorcin (B. 21, 2374 ; 22, 1285), and by the 
 action of dilute sulphuric acid upon dianilido-quinone (B. 23, 904 ; 
 31, 2402) ; and from its ethers by saponification. 2, 5-dimethoxy-, 
 diethoxy-, dipropoxy-quinone, m.p. 166, 183, and 187 respectively, 
 generated from quinone by boiling with alcohols and zinc chloride 
 (B. 34,3993). Treating with stannous chloride converts the 2, 5-dioxy- 
 quinone into sym. tetraoxy-benzol, while aniline converts it into 
 dianilido-quinone. Substitution products of 2, 5-dioxy-quinone have 
 been obtained from tetrachloro- and tetrabromo-quinone as substances. 
 Two of their halogen atoms are exchanged with extreme ease. 
 
 Chloranilic acid C 6 C1 2 (OH) 2 O 2 , reddish, shining scales, is separated 
 by acids from potassium chlomnilate C 6 C1 2 (OK) 2 O 2 + H 2 O, which 
 crystallises in dark-red needles, dissolving with difficulty in water. 
 Potassium chloranilate is produced as well from tri- as from tetrachloro- 
 quinone by the action of caustic potash. Hypochlorous acid, or chlorine, 
 acting upon chloranilic acid, produces tri- or tetrachloro-tetraketo-hexa- 
 methylene, which change quite readily with the intermediate production 
 of unstable oxy-acids into trichloro- and tetrachloro-triketo-pentamethylene 
 (B. 25, 827, 842). 
 
 Bromanilic acid C 6 Br 2 (OH) 2 O 2 corresponds to chloranilic acid, and 
 with bromine yields similar transposition products to those obtained 
 from it by the action of chlorine. 
 
 Nitranilic acid C 6 (NO 2 ) 2 O 2 (OH) 2 . It crystallises with water in 
 golden-yellow needles or plates, melts in its water of crystallisation, 
 becomes anhydrous at 100, and detonates at 170 without melting. 
 It is obtained from hydroquinone and quinone by nitrous acid ; on 
 conducting nitrous acid into an etheric quinone solution and cooling, 
 nitranilic quinone is produced, C 6 N 2 O 8 H 2 .C 6 H 4 O 2 , a combination 
 resembling a quinhydrone, decomposed by dilute potash into quinone 
 and nitranilic acid (B. 33, 3246). The latter is also generated from 
 chloranile with sodium nitrite, and from terephthalic acid and dioxy- 
 quinone-terephthalic acid by means of fuming nitric acid. When 
 nitro-anilic acid is reduced, it yields diamido-tetraoxy-benzene, which 
 renders possible the transition from chloranile to triquinoyl (see below), 
 and potassium hexaoxy-benzene. 
 
 Amido-anilic acid, diamido-dioxy-quinone C 6 (NH 2 ) 2 (OH 2 )O 2 , reddish- 
 blue needles, formed from diamido-tetraoxy-benzene by oxidation in 
 the air or by nitrous acid. 
 
 Potassium euthio-ehronate C 6 (SO 3 K) 2 (OH) 2 O 2 , see Dichloro-hydro- 
 quinone-disulphonic acid. 
 
 Tetraoxy-quinone C 6 (O 2 )(OH) 4 , formerly called dihydro-carboxylic 
 
OXY-QUINONES AND POLYQUINOYLS 231 
 
 acid, is obtained by oxidising the aqueous solution of hexaoxy-benzene 
 by exposure to the air (B. 18, 507, 1837). It may also be obtained 
 from diamido-dioxy-quinone by boiling with hydrochloric acid, as well 
 as by the action of concentrated nitric acid upon inosite. Metallic 
 black needles, with a green, metallic reflex. It is a strong dibasic acid. 
 
 Nitro-dioxy-quinone-sulphonie acid C 6 NO 2 (OH) 2 O 2 (SO 3 H). Its tri- 
 potassium salt, yellow needles, is produced by the action of K nitrite 
 upon K-dichloro-hydroquinone disulphonate (B. 38, 453). 
 
 Tetrathio-ethyl-quinone C 6 O 2 (SC 2 H 5 ) 4 , colourless prisms, m.p. 59, 
 from chloranil and sodium mercaptan (C. 1905, II. 1427). 
 
 Homologous oxy-quinones result upon treating haloid quinone homo- 
 logues with caustic potash, and on heating amido- or anilido-quinones 
 with alcoholic hydrochloric acid or sulphuric acid. Dianilido-tolu- 
 quinone, melting at 232, yields anilido-oxy-tolu-quinone, decomposing 
 at 250, and dioxy-tolu-quinone CH 3 .C 6 H(OH) 2 O 2 , melting at 177 
 (B. 16, 1559). Dioxy-m-xylo-quinone C 6 (CH 3 ) 2 O 2 (OH) 2 , red flakes, 
 m.p. 167, from amido-dimethyl-phloro-glucin (M. 21, i). Oxy-thymo- 
 quinone (C 3 H 7 )(CH 3 )C 6 H(OH) : O 2 , melting at 166, is obtained from 
 brom- or methyl-amido-thymo-quinone. Dioxy-thymo-quinone melts 
 at 213 (B. 14, 95). 
 
 p-Dialkylated dioxy-quinones, like p 2 -dimethyl-dioxy-benzo-quinone 
 C 6 (CH 3 ) 2 [3, 6](OH) 2 [2, 5]O 2 [i, 4], are formed as by-products during 
 the production of homologous oxal-acetic esters by condensation of 
 oxalic ester with fatty acid esters by means of sodium in etheric solu- 
 tion. They form red or yellowish-red compounds, dissolving in 
 alkalies with a violet colour. By reduction they give homologous 
 tetraoxy-benzols. On boiling with excess of soda lye, they are split 
 up into formations of homologous succinic acids. p 2 -Dimethyl, diethyl-, 
 and di-iso-propyl-dioxy-benzo-quinone melt at 245, 218, and 154 
 respectively (A. 361, 363). 
 
 It is also very probable that pipitzaholc acid C 15 H 19 (OH) : O 2 , found 
 in the root of Trixis pipitzahuac, and melting at 103, belongs to the 
 oxy-quinones, containing but one nucleus. It recalls, by its behaviour, 
 oxy-thymo-quinone. Oxy-pipitzahoic acid C 9 H 18 : C 6 (OH) 2 : O 2 (?), 
 melts at 138 (A. 237, 90). 
 
 Polyquinoyl Compounds. As mentioned under benzo-quinone 
 (p. 226), Woskresensky originally called this compound quinoyl. 
 Nietzki and Benckiser introduced this name in a different sense. They 
 applied it to the quinone group O 2 , when they discovered dioxy- 
 diquinoyl-benzene and triquinoyl-benzene to be bodies containing 
 more than one quinone group O 2 . For simplicity's sake they abridged 
 these names to dioxy-diquinoyl and triquinoyl. 
 
 Dioxy-diquinoyl C 6 (O 2 )(O 2 )(OH) 2 , called rhodizonic acid, is prepared 
 by reducing triquinoyl with aqueous sulphurous acid (B. 18, 513). It 
 consists of colourless leaflets, very readily soluble in water. It decom- 
 poses quite rapidly in aqueous solution. The potassium salt C 6 O 4 (OK) 2 
 may be obtained by treating the acid with potashes, and also by washing 
 potassium-hexaoxy-benzene (potassium-carbon monoxide) with alcohol. 
 It forms dark-blue needles, dissolving in water with an intense yellow 
 colour (B. 18, 1838). 
 
 Consult B. 23, 3140 for the constitution of rhodizonic acid. 
 
 Triquinoyl C 6 O 6 +8H 2 O is probably hexaketo-hexamethylene (B. 20, 
 
232 ORGANIC CHEMISTRY 
 
 322). It results upon oxidising dioxy-diquinoyl and diamido-tetraoxy- 
 benzene with nitric acid. It is a white, micro-crystalline powder (B. 18, 
 504 ; A. 350, 330). It melts about 95, giving up water and CO 2 . It 
 is likewise decomposed by warming it with water to 90. Stannous 
 chloride reduces it to hexaoxy-benzene, which is oxidised in alkaline 
 solution to tetraoxy-quinone C 6 (O 2 )(OH) 4 (see above). 
 
 Nietzki and Benckiser (1885) discovered the relations existing 
 between potassium-carbon monoxide and phenol. Compare the 
 following : 
 
 Phenol I C,H & OH C,(OK), Potassium -carbon 
 
 I monoxide 
 
 Tetrachloro-quinone j'C.CljCl.O, * C(OH 2 )(OH) 2 (OH), A Hexaoxy-benzene 
 
 Nitranilic acid j C,(NO 2 ) 2 (OH) 2 O 2 C,(OH) a (OH) 2 O 2 
 
 /f 
 Diamido-tetraoxy-benzol T C(NH 2 ) 2 (OH) 2 (OH)\/ C,(OH) 2 O 2 O, 
 
 / I 
 
 Diamido-dioxy-quinone * C,(NH 2 ) 2 (OH) 2 O, ' ^C.O 2 O a O a 
 
 Tetraoxy-quinone 
 
 Rhodizonic acid or 
 Dioxy-diquinoyl 
 Triquinoyl. 
 
 Addendum. Pentacarbocyclic compounds are readily formed from 
 triquinoyl and dioxy-diquinoyl, as well as from some hexa-substitution 
 derivatives of benzene, from which these polyquinoyl bodies arise e.g. 
 hexaoxy-benzene, diamido-tetraoxy-benzene, etc. They will accord- 
 ingly be discussed after the polyquinoyls. 
 
 Groconic acid hydride C 5 H 4 O 5 is formed upon treating rhodizonic 
 acid with excessive alkali, or croconic acid with hydriodic acid. It is 
 distinguished by its barium salt C 5 H 2 BaO 5 +2H 2 O. Its formation is 
 probably due to the breaking down of an unstable oxy-acid, produced 
 by the action of the caustic alkali upon two of the combined CO-groups 
 of the rhodizonic acid (see the rearrangement of benzilic acid) : 
 
 HO.C.CO.CO /HOC.OX /CO 2 H \ HOC.CO V /H HOC.CO, 
 
 II I (?)->( || >C< (?) )-> || >C< (?)-> || >CO(?) 
 
 HO.C.CO.CO VHOC.CO/ \>H / HOC.CO/ X OH HOC.CO/ 
 
 Rhodizonic acid Unstable oxy-acid Croconic acid hydride Croconic acid. 
 
 (B. 23, 3140) 
 
 Croconic acid C 5 O 3 (OH) 2 +3H 2 O consists of sulphur-yellow leaflets ; 
 it loses its water of crystallisation at 100. It dissolves very readily 
 in water and alcohol, and is produced by the alkaline oxidation of most 
 of the hexa-substituted benzene derivatives e.g. hexaoxy-benzene, 
 dioxy-diquinoyl, diamido-tetraoxy-benzene, etc. The hydride of 
 croconic acid is an intermediate product, which changes quite readily 
 to the acid. Triquinoyl, when boiled with water, decomposes into 
 carbon dioxide and croconic acid : 
 
 C 6 6 +H 2 = = C 5 H 2 5 +C0 2 . 
 
 Its potassium salt C 5 O 5 K 2 +3H 2 O crystallises in orange-yellow needles ; 
 hence the name, from xpdKos, safran (Gmelin, 1825). When oxidised 
 with nitric acid or chlorine the product is : 
 
 Leuconic acid C 5 O 5 +4tI 2 O, pentaketo-cyclo-pentane, which is recon- 
 verted into croconic acid by sulphur dioxide. This acid bears the same 
 relation to croconic acid that rhodizonic acid bears to triquinoyl. It 
 is very soluble in water, but dissolves with difficulty in alcohol and 
 ether. It crystallises in small colourless needles. The penta-oxime 
 C 5 (: N.OH) 6 , decomposing at 172, is isomeric with fulminic acid, 
 
QUINONE-NITROGEN DERIVATIVES 233 
 
 cyanic acid, cyanuric acid, and by reduction yields penta-amido-pentol 
 C 5 H(NH 2 ) 5 , penta-amido-cyclo-pentadiene (B. 22, 916). 
 
 QUINONE-NITROGEN DERIVATIVES. 
 
 The quinone oxygen atoms can be replaced by N(OH), NCI, NH, 
 NC 6 H 5 , and similar groups. 
 
 Quinone Dioximes. In connection with the p-nitroso-phenols, and 
 in the explanation of Fittig's diketone formula for p-quinone, it was 
 indicated that many chemists regarded the p-nitroso-phenols, resulting 
 from the action of hydroxylamine hydrochloride upon the p-quinones, 
 as monoximes of the latter. Indeed, the p-nitroso-phenols, by action 
 of hydroxylamine hydrochloride, change to p-quinone dioximes. It is 
 true these two classes can be viewed as constituted according to the 
 peroxide formula of the p-quinones. o-Quinone dioximes are formed 
 by the reduction of o-dinitroso-benzols ; by splitting off water they 
 easily pass into anhydrides, the so-called furazane derivatives (A. 
 307, 28). 
 
 Their dioximes unite with acetic anhydride to diacetyl compounds. 
 p-Dinitroso-benzols are produced by the oxidation of their alkaline 
 solutions (also on exposure to the air). Nitric acid oxidises them to 
 p-dinitro-benzols (B. 21, 428). 
 
 p-Quinone dioxime C 6 H 4 (N.OH) 2 consists of colourless or yellow 
 needles, which decompose at 240. 
 
 Tolu-quinone dioxime deflagrates at 220 (B. 21, 679). p-Xylo- 
 quinone dioxime melts at about 272 (B. 20, 978) . Mono- and dibenzoyl- 
 quinone dioxime, see C. 1903, I. 1409. 
 
 o-Quinone dioxime C 6 H 4 [i, 2](NOH) 2 , small yellow needles, dissolves 
 in alkalies with a blood-red colour, and passes into its colourless 
 anhydride C 6 H 4 N 2 O on simply standing, or warming in alkaline solution 
 
 (B. 40,4344). 
 
 Dinitro-resorcin and hydroxylamine yield diquinoyl trioxime 
 C 6 H 2 O(NOH) 3 , and diquinoyl tetroxime C 6 H 2 (NOH) 4 . The latter, 
 oxidised with sodium hypochlorite, yields tetranitroso-benzol (B. 30, 
 181 ; 32, 508). 
 
 Quinone imines are to be regarded as diketones, or as peroxides in 
 which the oxygen is represented by the imino-group (: NH) or the 
 alkyl-imino-group (: NR), corresponding to the formulae 
 
 C '<NH OT C H '<L and C H '\NH OT C ' 
 Quinone-mono-imine Quinone di-imine. 
 
 They are formed from p-amido-phenol or p-phenylene-diamine, by 
 gentle oxidation with silver oxide and lead peroxide in etheric solution. 
 In contrast with the quinones, they are colourless and exceedingly 
 unstable. They are strong oxidisers, smell like quinones, and are 
 volatile. On warming with mineral acids they decompose into ammonia 
 and quinone. By reduction with sulphurous acid or stannous chloride 
 and HC1, they are reconverted into the original substances, p-amido- 
 phenol and p-phenylene-diamine. Owing to the easy decomposition 
 of the o-quinones, the isolation of the o-quinone imines, which are prob- 
 ably even more unstable, has not been accomplished. The o-quinone 
 
234 ORGANIC CHEMISTRY 
 
 di-imine, probably first formed by the oxidation of o-phenylene- 
 diamine, polymerises at once to o-azo-aniline. 
 
 /[i]N=N[i] 
 4 \[2]NH 2 H 2 N[2] 
 
 (B. 38, 2348). 
 
 Quinone mono-imine O[i]C 6 H 4 [4]NH, colourless prismatic crystals, 
 which quickly turn dark in solution, and decompose in a short time 
 when dry (B. 37, 4607). 
 
 Quinone monomethyl-imine O[i]C 6 H 4 [4]NCH 3 , formed by oxida- 
 tion of p-methyl-amido-phenol OHC 6 H 4 NHCH 3 with Ag 2 O or PbO 2 . 
 It is still more unstable than the unmethylated imine, and deflagrates 
 immediately on formation (B. 38, 2251). 
 
 Quinone di-imine NH[i]C ? H 4 [4]NH, m.p. about 129, is also formed 
 by reduction of p-quinone dichlor-imine with HC1 in etheric solution. 
 It forms colourless monoclinic prisms, which are quickly browned 
 in air (B. 37, 4606). With sodium disulphite it unites to form a 
 mixture of p-amido-phenol-sulphonic acid and p-phenylene-diamine- 
 sulphonic acid. 
 
 Quinone monomethyl-di-imine NH[i]C 6 H 4 [4]NCH 3 , m.p. 64-67, 
 and quinone dimethyl-di-imine CH 3 N[i]C 6 H 4 [4]NCH 3 , m.p. 93, result, 
 like the simple quinone di-imines, from the oxidation of monomethyl- 
 or sym. dimethyl-p-phenylene-diamine. They form almost colourless 
 crystals, dissolving with a light-yellow coloration. They are as 
 unstable as the non-methylated quinone di-imine (B. 38, 2249 ; 40, 
 2672). 
 
 Unsym. quinone-dimethyl-di-imonium nitrate NH : [i]C 6 H 4 [4] : 
 N(CH 3 ) 2 NO 3 , HNO 3 is obtained in the form of very unstable light- 
 yellow prisms by the oxidation of unsym. dimethyl-p-phenylene- 
 diamine with nitrous gases. It decomposes rapidly, and deflagrates 
 on heating. With one molecule of its hydro-compound the unsym- 
 metrical dimethyl-p-phenylene-diamine, it unites to form a body, 
 [NO 3 NH 2 :C 6 H 4 :N(CH 3 ) 2 N0 3 +NH 2 C 6 H 4 N(CH 3 ) 2 ], of a structure 
 resembling quinhydrone, green crystals dissolving in water with a 
 red fuchsine coloration. These interesting compounds, called 
 Wurster's red after their discoverer, result from the partial oxidation 
 of salts of unsym. dimethyl-p-phenylene-diamine (B. 12, 1803, 2071). 
 The corresponding bromo-hydrate, m.p. 147 with decomposition, in 
 green crystals, results from the action of one atom bromine upon 
 unsym. dimethyl-p-phenylene-diamine in glacial acetic acid solution. 
 Reducers bleach the deep-red solution, with formation of phenylene- 
 diamine. Oxidisers do the same, and form the entirely quinoid com- 
 pound (B. 41, 1458). 
 
 Analogous blue compounds are obtained by starting from tetra- 
 methyl-p-phenylene-diamine (Wurster's blue, B. 12, 1807 ; 41, 1473). 
 Unstable oxidation products coloured an intense green, or blue, have 
 also been obtained from p-phenylene-diamine and dibromo-p-phenylene- 
 diamine (C. 1904, I. 1073 ; B. 38, 3354). 
 
 Amido-quinone imine NH 2 [2]C 6 H 3 [i]O[4]NH and its homologues 
 are formed by oxidation of 2, 4-diamido-phenols with ferric chloride. 
 The bichromate forms greenish-black, brilliant grains, dissolving in 
 water with a red colour (B. 39, 3437). 
 
QUINONE-NITROGEN DERIVATIVES 235 
 
 Diamido-quinone imine (NH 2 ) 2 C 6 H 2 (O)(NH)(?) is obtained from 
 triamido-phenol (A. 215, 351). 
 
 Quinone Chlorimines. They are produced from p-amido-phenols 
 and p-phenylene-diamines (their HC1 salts) by oxidation with an 
 aqueous solution of bleaching lime. They revert to p-amido-phenols 
 or p-phenylene-diamines upon reduction. The monochlorimines form 
 the indo-phenol dyestuffs with phenols and tertiary anilines. 
 
 Quinone monoehlorimine O[i]C 6 H 4 [4]NCl forms golden-yellow 
 crystals, which melt at 85, volatilise readily with steam, and smell 
 like quinone. It is easily soluble in hot water, alcohol, and ether. 
 When boiled with water it decomposes into NH 4 C1 and quinone (/. 
 pr. Ch. 2,23,435). 
 
 Quinone dichlorimine C 6 H 4 [i, 4](N 2 C1 2 ) crystallises in needles 
 which deflagrate at 124 (B. 12, 47). 
 
 Trichloro-quinone chlorimine, m.p. 118 (/. pr. Ch. 2, 24, 429). 
 
 Dibromo-quinone chlorimine, m.p. 80 (B. 16, 2845). 
 
 Quinone-phenyl-hydrazones. While phenyl-hydrazin and alkylated 
 phenyl-hydrazins are oxidised by quinone, o-nitro- and o, p-dinitro- 
 phenyl-hydrazins give condensation products which may be interpreted 
 as p-oxy-azo-compounds, being identical with the coupling products 
 of diazotised o-nitro- or o, p-dinitraniline and phenol (A. 357, 171). 
 With a-acetyl- and benzoyl-phenyl-hydrazins, on the other hand, true 
 quinone-phenyl-hydrazones are generated. 
 
 Quinone - acetyl- and benzoyl - phenyl - hydrazone O : C 6 H 4 : NN 
 (Ac)C 6 H 5 , m.p. 118 and 171 respectively, which, however, are easily 
 transposed into the acylated p-oxy-azo-compounds AcOC 6 H 4 N 2 C 6 H 5 
 (B. 40, 1432). This reaction has acquired a special importance for 
 determining the constitution of the oxy-azo-compounds. The o- 
 quinone-benzoyl-phenyl-hydrazone (?) yields, by its hydrolytic decom- 
 position, o-oxy-azo-benzol (C. 1909, I. 1093). 
 
 Quinone-oxime-hydrazones result from the action of benzoyl-hydra- 
 zin and benzoyl-phenyl-hydrazin upon nitroso-phenols. Quinone- 
 oxime-benzoyl-hydrazone (HON) : C 6 H 4 : NNH.COC 6 H 5 , m.p. 210 
 with decomposition. Quinone-oxime-benzoyl-phenyl-hydrazone (HON) : 
 C 6 H 4 : NN(COC 6 H 5 )C 6 H 5 , on boiling with HNO 3 , yields p-nitro-azo- 
 benzol (A. 343, 176). 
 
 Quinone semi-carbazone and Amido-guanidone. The quinones 
 react more readily with semi-carbazide and with amido-guanidin than 
 with phenyl-hydrazin. Quinone mono- and bi-semi-carbazone C 6 H 4 O 
 (NNHCONH 2 ) and C 6 H 4 (NNHCONH 2 ) 2 , m.p. 171 and 243 respect- 
 ively, are obtained from quinone and HC1 semi-carbazide. Quinone 
 mono- and bis-amido-guanidone C 6 H 4 O[NNHC(NH)NH2] and C 6 H 4 
 [NNHCtNHJNHJg are obtained from amido-guanidin nitrate and 
 quinone in the presence of nitric acid (A. 302, 311). The quinone 
 mono-semi-carbazone and mono-amido-guanidone are probably oxy- 
 azo-compounds (A. 334, 143). 
 
 Quinone Azines. p-Quinone azine O[4]C 6 H 4 [i]N.N[i]C 6 H 4 [4]O 
 deflagrates at 158. It is formed by oxidation of p-azo-phenol 
 with Ag 2 O and PbO 2 in etheric solution. It is obtained in the 
 form of dark orange prisms or dark yellow rhombohedral flakes. 
 It is stable in air, and is odourless and not volatile. Reduction with 
 sulphurous acid or phenyl-hydrazin reconverts it into p-azo-phenol, 
 
236 ORGANIC CHEMISTRY 
 
 while stannous chloride and HC1 produce p-amido-phenol. With one 
 molecule of p-azo-phenol it combines to form a compound resembling 
 quinhydrone, blue-black needles of m.p. 182, also obtainable by direct 
 oxidation of p-azo-phenol. o- and m-Azo-phenol yield no quinone 
 azines. 
 
 Quinone Dlazides. It has been already pointed out in connection 
 with the diazo-salts of the o- and p-amido-phenols that the correspond- 
 ing diazo-hydrates easily pass into yellow anhydrides related to the 
 quinones, and probably interpretable as o- and p-quinone diazides 
 
 ..^>C 6 H 4 : O. Similar behaviour is shown by the diazonium salts of 
 p-amido-diphenyl-amine NH 2 C 6 H 4 NHC 6 H 5 , which, on treatment with 
 
 N\ 
 
 ammonia, form p-quinone diazide anile II >C 6 H 4 : NC 6 H 5 (B. 35, 888). 
 
 / 
 
 /o 
 Quinone-phenyl mono-imine, quinone monoanil c^/ | or 
 
 \JN v^^iri-^ 
 
 C 6 H 4 ^ , m.p. 97, consists of fiery-red crystals. It is formed 
 
 upon oxidising p-oxy-diphenyl-amine in benzene solution with mercuric 
 oxide, and upon reduction reverts to the same (B. 21, R. 434). 
 
 Indo-phenols and Indo-anilines. These compounds are obtained 
 from quinone monoanile or quinone phenyl-imide by replacing the 
 p-hydrogen atom of the anile group by an OH or an NH 2 group. 
 They are dyes. Like many members of this class, they are de- 
 colorised by the addition of hydrogen. The resulting bodies are 
 leuco-compounds, p-di-substituted diphenyl-amines. (Nomenclature, 
 B. 29, R. 94.) 
 
 Indo-phenols are produced (i) by allowing the quinone chlorimines 
 to act upon phenols ; (2) by oxidising a mixture of a p-amido-phenol 
 and phenol. They dissolve in alcohol with a red colour, and possess 
 a character similar to phenol. Their salts, with the alkalies and am- 
 monia, dissolve in water with a blue colour. 
 
 /N.C 6 H 4 OH 
 
 Quinone phenol-imine C 6 H 4 / | also results upon heating 
 
 phenol blue with soda lye (B. 18, 2916), but, owing to its instability, 
 cannot be obtained in a free condition. By reduction it changes to 
 colourless p-dioxy-diphenyl-amine from which it can be recovered by 
 
 HgO (B. 32, 689). Dibromo-quinone phenol-imine c^Br/ \ ' * 
 
 \o 
 
 from dibromo-quinone chlorimine, is more stable than quinone-phenol- 
 imine. Free dibromo-phenol-imine crystallises in dark-red prisms 
 having a metallic lustre ; they dissolve in alcohol and ether with a 
 fuchsine-red colour. Strong mineral acids decompose it into dibromo- 
 phenol and quinone. 
 
 The Indo-anilines are produced (i) by the action of quinone chlori- 
 mine upon dimethyl-aniline in alcoholic solution ; (2) by the action 
 of nitroso- and nitro-dimethyl-aniline upon phenol in alkaline solution, 
 especially in the presence of reducing agents (Witt, 1879) ; (3) by the 
 oxidation in alkaline solution (with sodium hypochlorite) of a mixture 
 of a p-phenylene-diamine with a phenol, or of a p-amido-phenol with 
 a primary monamine, or by means of lead peroxide or manganese 
 
QUINONE PHENYL-DI-IMINES 237 
 
 peroxide in the presence of di-sodium phosphate (1877, Nietzki ; B. 
 28, R. 470 ; C. 1908, I. 437 ; 1906, II. 477). 
 
 The indo-anilines are feeble bases. They are rather stable towards 
 the alkalies ; acids quickly decompose them into quinones and the 
 p-phenylene-diamines. They are changed to the leuco-compounds ; 
 amido-oxy-diphenyl-amines, by reduction (absorption of two hydrogen 
 atoms) ; these dissolve readily in alkalies, and are readily reconverted 
 (oxidised) into indo-anilines (by exposure of their alkaline solution 
 to the air). The free indo-anilines have a deep-blue colour, and can 
 be applied as dyestuffs. For this purpose they are converted into 
 their alkaline leuco-derivatives, which are soluble, and the material 
 is impregnated or printed with these. Oxidation (by exposure to the 
 air or with K 2 Cr 2 O 7 ) develops the colour. The simplest aniline is 
 
 /N.C 6 H 4 .NH 2 
 quinone anilin-imine C,H 4 ( | , a violet dye, formed by the 
 
 \O 
 
 oxidation of p-phenylene-diamine C 6 H 4 (NH 2 ) 2 with phenol. Quinone 
 
 /N.C 6 H 4 .N(CH 3 ) 2 
 
 dimethyl-anilin-imine (phenol blue) C 8 H 4 ^ | results from 
 
 unsym. dimethyl-p-phenylene-diamine and phenol. It has a greenish- 
 blue colour and dissolves in acids with a blue colour. When boiled 
 with soda lye it splits off dimethyl-amine and becomes quinone-pheno- 
 limine. Sulphuric acid decomposes it into quinone and dimethyl-p- 
 phenylene-diamine. This is a general reaction, hence can be used 
 opportunely for the preparation of quinones (B. 28, R. 471 ; 29, R. 24). 
 
 QUINONE PHENYL-DI-IMINES. 
 
 Quinone mbnophenyl-di-imine C 6 H 5 N : C 6 H 4 : NH, light-yellow 
 prisms, m.p. 89, by oxidation of p-amido-diphenyl-amine with silver 
 oxide or lead peroxide in etheric solution. It is also formed, besides 
 quinone monoanile, during the gentle oxidation of aniline in an aqueous 
 alkaline solution. Water splits it up, even when cold, into ammonia 
 and quinone monoanile. On heating with dilute sulphuric acid it 
 passes into quinone. Mineral acids readily polymerise it to form a 
 green dye, enter aldin. The latter is also formed when p-amido- 
 diphenyl-amine is oxidised in an acid solution with ferric chloride or 
 hydrogen peroxide, also by reduction of nitro-benzol in a hydrofluo- 
 silicic acid solution, the body first formed being p-amido-diphenyl- 
 amine. The free base separated from emeraldin, the so-called azurin, 
 m.p. 165, forms deep-blue prisms, and probably has the con- 
 stitution C 6 H 6 NH.C 6 H 4 NH.C 6 H 4 N : C 6 H 4 : NH. By oxidation with lead 
 peroxide in benzene solution this half-quinoid azurin or emeraldin, 
 respectively, may pass into a doubly quinoid red imine C 6 H 4 N : 
 C 6 H 4 N : C 6 H 4 N : CgH 4 : NH, which, after the manner of quinone 
 monophenyl-di-imine, polymerises, under various conditions, to a 
 black dye called aniline black (B. 40, 2665 ; 42, 4123). 
 
 Aniline black* is one of the oldest known organic dyestuffs, and is 
 distinguished by its permanence. It is formed by the oxidation of 
 aniline salts with potassium bichromate and sulphuric acid, ammonium 
 
 * E. Noelting and R. Lehne, AnilinscJiwarz und seine Anwendung in Farberei 
 und Zeugdruck, 2nd ed., Berlin, 190.}, Springer. 
 
238 ORGANIC CHEMISTRY 
 
 persulphate, or potassium chlorate, in the presence of oxygen carriers 
 such as copper sulphate, potassium ferrocyanide, ammonium vanadate, 
 etc. In its applications to cotton-dyeing aniline black is produced in 
 the fibre, by printing the fabric with a mixture of aniline salt and one 
 of the above-mentioned oxidisers, and then developing the dye by 
 steaming at a low temperature. 
 
 Aniline black has a relation to the red oxidation product of emer- 
 aldin, resembling the relation between emeraldin and quinone mono- 
 phenyl-di-imine. It cannot be looked upon as a unitary compound. 
 It consists of a mixture varying with the degree of oxidation, a triple 
 or quadruple quinoid combination, to which the following constitu- 
 tional formulae are attributed : 
 
 I. C 6 H 6 N : C fl H 4 : NC 6 H 4 NHC 6 H 4 NHC 6 H 4 N : C 6 H 4 : NC 6 H 4 N : C 6 H 4 : NH. 
 II. C 6 H 6 N : C 6 H 4 : NC 6 H 4 N : C 8 H 4 : NC 6 H 4 N : C 6 H 4 : NC 6 H 4 N : C 6 H 4 : NH. 
 
 On heating with dilute H 2 SO 4 , one-eighth of the total nitrogen is 
 split off in the form of ammonia, the imino-group being replaced by 
 oxygen. This is accompanied by an increase in the depth of the colour. 
 These oxygen-bearing substances are contained in aniline black in 
 proportions varying according to the method of preparation. Strong 
 oxidation with chromic acid or lead peroxide and H 2 SO 4 converts it 
 almost quantitatively into quinone (B. 42, 2147, 4118). 
 
 Quinone diphenyl - di - imine, diphenyl-p-azo-phenylene, quinone 
 dianile C 6 H 4 (NC 6 H 5 ) 2 m.p. i76-i8o, is obtained by the oxidation 
 of diphenyl-amine and diphenyl-p-phenylene-diamine (B. 21, R. 656). 
 By reduction, quinone dianile passes into diphenyl-p-phenylene-di- 
 amine, with which it is related as quinone is to hydroquinone. 
 
 Two phenyl-amido-groups may be introduced into the benzene 
 residue of quinone anile and quinone dianile with the same facility as 
 into quinone itself, which, as mentioned before, gives rise to di-anilido- 
 quinone and hydroquinone on boiling its alcoholic solution with aniline. 
 If acetic acid is present (B. 18, 787), dianilido-quinone anile is formed, 
 (C 6 H 5 NH) 2 C 6 H 2 (O)(NC 6 H 5 ), m.p. 202, brownish-red needles. This is 
 also formed on heating quinone mono-anil with aniline besides p-oxy- 
 diphenyl-amine (B. 21, R. 656) and on oxidising aniline with H 2 O 2 in a 
 feebly acid solution (B. 15, 3574). 
 
 Dianilido-quinone dianile, azo-phenin (CeHjNHJ^H^NCjjHg),, m.p. 
 241, garnet-red flakes, results (i) on heating quinone dianile with 
 aniline (B. 21, R. 656) ; (2) on melting quinone with aniline and aniline 
 chlorohydrate (B. 21, 683) ; (3) from amido-azo-benzol, p-nitroso- 
 phenol, p-nitroso-diphenyl-amine by the action of aniline (B. 20, 2480). 
 On heating it is converted into fluorindin (B. 23, 2791 ; 31, 1789). 
 
 The quinone dianiles are important links in the formation of 
 indulin dyes (B. 25, 2731 ; A. 262, 247). 
 
 Indamines. These are derived from the indo-anilines by the re- 
 placement of the quinone-oxygen atom by the imido- or alkyl-imido- 
 group. They are therefore derivatives of the unknown quinone di- 
 imide, and bear an intimate relation to p-diamido-diphenyl-amine, 
 which is formed by the reduction of the simplest indamine and is the 
 leuco-derivative of the latter. 
 
 The indamines arise (i) by oxidation, in neutral solution and in the 
 cold, of a mixture of a p-phenylene-diamine with an aniline (Nietzki), 
 
INDAMINES 239 
 
 or (2) by the action of nitroso-dimethyl-aniline upon anilines or m-di- 
 amines (Witt). They are feeble bases, forming blue- or green-coloured 
 salts with acids ; but with an excess of the latter are very easily split up 
 into quinone and the diamine. Because of their instability they find 
 no application, and are only important as intermediate products in the 
 manufacture of thionin and safranin dyestuffs (into which they can be 
 readily transposed). For the relations of the indo-phenols, indanilines, 
 and indamines to the dyes of the oxazin-, thiazin-, and diazin-series 
 e.g. resorufm, methylene blue the indulins and safranins, see the 
 latter. The simplest indamine is : 
 
 /N.CH 4 NH 2 
 Phenylene blue C 6 H 4 <^ | . This is produced by the oxida- 
 
 tion of p-phenylene-diamine with aniline. Its salts are greenish-blue 
 in colour. It yields diamido-diphenyl-amine by reduction. Its tetra- 
 methyl derivative is : 
 
 Dimethyl-phenylene green N <^ 6 2 4 'SSv, (Bindschedler's green). 
 
 This is obtained by oxidising dimethyl-paraphenylene-diamine with 
 dimethyl-aniline. Its salts dissolve in water with a beautiful green 
 colour. Its reduction yields tetramethyl-diamido-diphenyl-amine. 
 Digestion with dilute acids resolves it into quinone and dimethyl-amine 
 (B. 16, 865 ; 17, 223). On standing with soda lye, dimethyl-amine 
 splits off and phenol blue is produced ; this further separates into 
 quinone phenol-imide (B. 18, 2915). 
 
 Toluylene blue N <fS*S 4 *^^U results from ordinary toluylene- 
 
 diamine by oxidising it mixed with dimethyl-p-phenylene-diamine, 01 
 by the action of HCl-nitroso-dimethyl-aniline. Its salts with one equi- 
 valent of acid are of a beautiful blue colour, and are decolorised by 
 an excess of mineral acids with formation of the diacid salts. It is 
 converted into toluylene red on boiling with water. 
 
 The genetic connection of the indamines with the indo-anilines and 
 indo-phenol is shown in the possibility of converting the simplest ind- 
 amine into quinone-aniline-imine, and the latter into quinone-phenol- 
 imine (Mohlau, B. 16, 2843 ; 18, 2915). 
 
 Representatives of the indo-phenols, indo-anilines, and indamines 
 containing the naphthalin residue are also known in great numbers, 
 and many, likenaphthol blue (q.v.} or " indo-phenol," have been applied 
 technically (B. 18, 2916). 
 
 On quinoid sulphur compounds, see B. 40, 3039 ; 41, 902. 
 
 9. Phenyl-paraffin Alcohols and their Oxidation Products. 
 
 In the preceding sections those classes of aromatic hydrocarbons 
 containing one nucleus were described, which resulted from the sub- 
 stitution of the hydrogen atoms of benzene or the benzene residue of 
 the alkyl-benzenes by atoms of other elements or by atomic groups : 
 the halogen substitution products, the nitrogen-containing derivatives 
 of the benzene hydrocarbons, the aromatic phosphorus, arsenic, anti- 
 mony, bismuth, boron, silicon, and tin derivatives, the phenyl metal 
 
240 ORGANIC CHEMISTRY 
 
 compounds, the sulpho-acids and their relatives, the phenols, and the 
 quinones. 
 
 Attached to these are those classes of bodies formed by the replace- 
 ment of hydrogen atoms in the side groups of the alkyl-benzols. As in 
 the aliphatic series, the oxygen-containing products are considered the 
 most important. Each class of these derivatives is followed by the 
 corresponding halogen, sulphur, and nitrogen compounds, in which all, 
 or at least a part, of the carbon valences, saturated in the principal 
 compounds by oxygen, are taken up with the elements just named. 
 Prominent among these, as with the aliphatic derivatives, are those 
 bodies in which one carbon atom of an alkyl side chain is combined 
 with oxygen : 
 
 (i#) The monohydric phenyl-paraffin alcohols and their oxidation 
 products : aldehydes, ketones, carboxylic acids. 
 
 Naturally these compounds, as far as the reactivity of the aliphatic 
 residue is concerned, manifest great similarity to the monohydric ali- 
 phatic alcohols and their oxidation products (Vol. I.). This is recalled 
 by their nomenclature and the view that they are phenyl-substitution 
 products of aliphatic substances. 
 
 Each of these alkyl-benzene derivatives constitutes a fundamental 
 substance from which, by the replacement of hydrogen atoms of the 
 phenyl residue, as with benzene itself, numerous derivatives can be 
 deduced. In general the benzene substitution products of the phenyl 
 fatty bodies, so far as they are worth mention, will be introduced after 
 the corresponding principal bodies. Only the derivatives of mono- 
 hydric aromatic alcohols, having hydroxyl in their benzene residue, 
 and their oxidation products, which manifest at the same time a phenol 
 character, will be grouped together as : 
 
 (ib) Monohydric oxy -phenyl-paraffin alcohols and their oxidation 
 products. 
 
 Then will follow (2) polyhydric phenyl-paraffin alcohols, in which but 
 one hydroxyl group is joined to a side chain, and their oxidation products. 
 The conclusion of this section will be (3) polyhydric phenyl-paraffin 
 alcohols, in which more than one hydroxyl group is attached to a side chain, 
 and their oxidation products. 
 
 In the subsequent sections the mononuclear derivatives with 
 unsaturated side chains will be summarised. 
 
 (a) MONOHYDRIC PHENYL-PARAFFIN ALCOHOLS AND THEIR 
 OXIDATION PRODUCTS. 
 
 i. Monohydric Phenyl-paraffin Alcohols. The true alcohols of the 
 benzene series are produced by the entrance of an hydroxyl group 
 into the side chain of an alkyl-benzol, primary, secondary, and tertiary. 
 The primary alcohols, upon oxidation, yield aldehydes and acids. The 
 secondary change to ketones : 
 
 I Benzyl alcohol C 6 H 5 CH 2 OH I Phenyl-methyl-carbinol C 6 H 5 CH(OH)CH 3 
 I Benzaldehyde C 6 H B CHO * Acetophenone . . C 6 H 5 COCH 3 . 
 
 i Benzole acid C 6 H 5 COOH. 
 
 Formation. The similarity of benzyl alcohol and its homologues 
 to ethyl alcohol finds expression at the very outset in the methods of 
 
MONOHYDRIC PHENYL-PARAFFIN ALCOHOLS 241 
 
 producing both classes : (i) by saponification of alkyl-benzols con- 
 taining an halogen atom in the side chain the haloid acid esters of 
 the benzyl alcohols e.g. benzyl chloride with water alone (A. 196, 353), 
 with water and lead oxide (A. 143, 81), or with potashes. Benzyl 
 alcohols are also produced by converting the chlorides into acetates 
 and saponifying the latter. 
 
 (2) By the action of nitrous acid upon primary amines, the reduction 
 products of aromatic acid nitriles e.g. cumo- and hemimelli-benzyl 
 alcohol. 
 
 (3) By the action of nascent hydrogen on the corresponding alde- 
 hydes and ketones. 
 
 (4) The phenyl-paraffin alcohols are obtained from the aromatic 
 aldehydes by treating with alcoholic or aqueous potash. This reaction, 
 in which the corresponding carboxylic acids are also formed, occurs 
 only exceptionally in the paraffin aldehydes (B. 14, 2394 ; C. 1902, 
 I. 1212) ; from two molecules benzaldehyde, benzyl alcohol and 
 potassium benzoate are produced, benzoic benzyl ester being probably 
 an intermediate product (C. 1899, II. mi) : 
 
 2C 6 H 5 CHO > C 6 H 5 COOCH 2 C 6 H 5 -> C 6 H 5 COOK-f C 6 H 6 CH 2 OH. 
 
 (5#) From the aromatic carboxylic acids or their esters by electro- 
 lytic reduction in alcoholic sulphuric- acid solution, with great excess 
 of cathode voltage. The reduction of the acid esters leads simul- 
 taneously to the formation of the corresponding ethers ; benzoic 
 methyl ester gives benzyl alcohol and benzyl-methyl ether C 6 H 5 CH 2 
 OCH 3 (B. 38, 1745 ; 39, 2933 ; C. 1908, II. 1863). 
 
 (56) From the esters of the phenyl fatty acids (except benzoic acid) 
 by reduction with sodium and alcohol (German patent 164,294). 
 
 (5c) By reducing amides of aromatic carboxylic acids, containing 
 the carboxylic group attached to the benzene nucleus, with sodium 
 amalgam in acid solution (B. 24, 173). 
 
 (6) By the reduction of unsaturated alcohols. Cinnamyl alcohol 
 C 6 H 6 CH=CH.CH 2 OH becomes hydro-cinnamyl alcohol C 6 H 5 .CH 2 .CH 2 . 
 CH 2 OH (see Allyl Alcohol). 
 
 (7) They are formed in the nuclear synthesis by the action of 
 metallic alkylates upon aldehydes, ketones, acid esters or acid chlorides, 
 and halogen hydrins. Thus (a) phenyl-magnesium bromide and 
 acetone yield phenyl-dimethyl-carbinol C 6 H 6 C(OH) (CH 3 ) 2 ; (b) aromatic 
 aldehydes, ketones, acid esters, or chlorides with zinc alkyls, and 
 especially magnesium-alkyl haloids (Vol. I.), give secondary and 
 tertiary phenyl-paraffin alcohols, the latter easily losing water, and 
 passing into olefin benzols (C. 1901, I. 1357 > H- 623 '> B. 35, 2633) ; 
 (c) phenyl-magnesium bromide and ethylene chlorohydrin yield phenyl- 
 ethyl alcohol C 6 H 5 CH 2 CH 2 OH (C. 1907, I. 1033). 
 
 Benzyl alcohol, phenyl-carbinol [phenyl-methylol] C 6 H 5 CH 2 OH, m.p. 
 206, with specific gravity 1-062 (o), is isomeric with the cresols. It 
 occurs as benzoic ester and benzyl-cinnamic ester in the balsams of 
 Peru and Tolu, and in storax (A. 169, 289) ; as an acetic ester, and 
 sometimes free in certain etheric oils, e.g. the oil of jasmine flowers 
 (B. 32, 567). 
 
 It is produced by the methods (i), (2), (3), (4), (5), and (5c), given 
 VOL. II. E 
 
242 ORGANIC CHEMISTRY 
 
 above, from benzaldehyde, benzyl chloride, benzole acid, and benz- 
 amide. Reactions (i) and (3) are used as methods of preparation. It 
 is a colourless liquid, with a faint aromatic odour. It dissolves with 
 difficulty in water, but readily in alcohol and ether. It yields benz- 
 al^lehyde and benzoic acid when oxidised. On heating with hydro- 
 chloric acid or hydrobromic acid, the OH group is replaced by halogens. 
 Benzoic acid and toluol result on distilling it with concentrated potash. 
 History. As early as 1832 Liebig and Wohler, in the course of 
 their celebrated investigation upon the radical benzoyl, obtained 
 this alcohol as the result of the interaction of alcoholic potash and 
 benzaldehyde (A. 3, 254, 261). Cannizzaro (1853) was the first to 
 discover the alcohol in studying this reaction. 
 
 Homologous Phenyl-paraffin Alcohols. The primary alcohols are 
 chiefly made by methods (i), (2), (3), (4), (50), (56), (5c), and (jc) ; 
 hydro-cinnamyl alcohol by method (6) ; the secondary alcohols by 
 method (i), or by the reduction of the ketones according to method (3), 
 and the tertiary alcohols, like benzyl-dimethyl carbinol, by method (7) . 
 Nucleus homologous benzyl alcohols : 
 
 M.p. B.p. 
 
 o-Tolyl carbinol . CH 3 [2]C 6 H 4 [i]CH 2 OH 34 223 (B. 24, 174) 
 
 m-Tolyl carbinol . CH 3 [3]C 6 H 4 [i]CH 2 OH liquid 217 (B. 18, R. 66) 
 
 p-Tolyl carbinol . CH 3 [ 4 ]C 6 H 4 [i]CH 2 .OH 59 217 (A. 124, 255) 
 
 2, 4-Dimethyl-benzyl 
 
 alcohol . . (CH 3 ) 2 [2, 4 ]C 6 H 3 [i]CH 2 .OH 22 232 (B. 21, 3085) 
 
 3, 5-Mesityl alcohol . (CH 3 ) 2 [ 3 , 5 ]C 6 H 3 [i]CH 2 .OH liquid 220 (B. 16, 157?) 
 
 2, 4, 5-Cumo-benzyl al- \ 
 
 cohol . . (CH 3 ) 3 [2, 4 ,5]C 6 H 2 [i]CH 2 .OH 168 .. I (B . } 
 
 3, 4, 5-Hemimelli-benzyl ( v 
 
 alcohol . . (CH 3 ) 3 [3, 4 , 5 ]C 6 H 2 [i]CH 2 .OH 78 .. J 
 Mellithyl alcohol (CH 3 ) 5 C 6 .CH 2 OH 160 .. (6.22,1217) 
 
 p-Cumin alcohol . (CH 3 ) 2 CH[4]C 6 H 4 [i]CH 2 .OH . . 246. 
 
 Other homologues are the phenyl-ether alcohols : 
 
 Benzyl carbinol C 6 H 5 CH 2 .CH 2 OH, p-phenyl- ethyl alcohol, a main 
 constituent of the etheric oil of roses (B. 34, 2803), boils at 219 
 (B. 9, 373). 
 
 Phenyl-methyl carbinol C 6 H 5 .CH(OH)CH 3 boils at 203, from 
 benzaldehyde and CH 3 MgI (C. 1901, II. 623). 
 
 o-, m-, and p-tolyl-ethyl alcohol CH 3 C 6 H 4 CH 2 CH 2 OH, b.p. 243-5, 
 243, and 245, from the tolyl-magnesium bromides with ethylene 
 chlorohydrin (C. 1907, I. 1033), or by electrolytic reduction of the 
 three isomeric tolyl-acetic acids (C. 1908, II. 1863). 
 
 Phenyl-propyl Alcohols. Hydro-cinnamyl alcohol C6H 5 .CH 2 .CH 2 . 
 CH 2 OH boils at 235. It is obtained from its cinnamic acid ester,' 
 which is present in storax (A. 188, 202). Benzyl-methyl earbinol 
 C 6 H 5 .CH 2 .CH(OH).CH 3 boils at 215. Phenyl-ethyl carbinol C 6 H 5 
 CH(OH)CH 2 CH 3 , b.p. 221, obtained like phenyl-propyl. 
 
 Phenyl-iso-propyl, phenyl-iso-butyl, and phenyl-iso-amyl carbinol, 
 b.p. 10 114, b.p. 15 113, b.p. 9 122 and b.p. 8 132 respectively, from 
 benzaldehyde, with the corresponding alkyl-magnesium iodides 
 (C. 1901, II. 623). 
 
 Phenyl-dimethyl carbinol C 6 H 5 C(OH)(CH 3 ) 2 , m.p. 23, b.p. 10 94, 
 
DERIVATIVES OF PHENYL-PARAFFIN ALCOHOLS 243 
 
 is obtained from phenyl-magnesium bromide with acetones, or from 
 aceto-phenone and benzoic methyl ester with magnesium-methyl 
 iodide. Benzyl-dimethyl carbinol C 6 H 6 .CH 2 .C(OH)(CH 3 ) 2 , m.p. 21, 
 b.p. 225. For further dialkyl-benzyl carbinols, see C. 1904, I. 1496. 
 DERIVATIVES OF THE PHENYL-PARAFFIN ALCOHOLS. Haloid Esters. 
 Benzyl chloride and benzyl bromide are produced when chlorine or 
 bromine acts upon boiling toluol (Beilstein, A. 143, 369). The action 
 is favoured by sunlight (C. 1898, I. 1019). Benzyl chloride, bromide, 
 and iodide are also formed from benzyl alcohol and the haloid acids, 
 and benzyl iodide by the action of potassium iodide upon benzyl 
 chloride (A. 224, 126) : 
 
 Benzyl chloride . . C 6 H 5 .CH 2 C1 liquid b.p. 176 
 
 Benzyl bromide .. . C 6 H 5 .CH 2 Br 210 
 
 Benzyl iodide . . C 6 H 5 .CH 2 I melts at 24 and decomposes. 
 
 Benzyl chloride, isomeric with the three chloro-toluols, is an im- 
 portant reagent, by means of which numerous derivatives of benzyl 
 alcohol have been prepared, as its chlorine atom is readily exchanged. 
 It passes into benzyl alcohol when boiled with water. Heated with 
 water and lead nitrate it yields benzaldehyde, and by oxidation 
 benzoic acid : 
 
 r TJ I-TJ r TI rw ri S > C 6 H 5 .CH,OH 
 
 C 6 H 5 CH S - > C,H 6 .CH 2 U- - J ^ C 8 H 5 .CHO > C 6 H 5 COOH. 
 
 The following ethers have been made by the action of sodium 
 alcoholates upon benzyl chloride, or by electrolytic reduction of benzoic 
 esters (B. 38, 1752). Benzyl-methyl ether boils at 168, obtained from 
 phenyl-magnesium bromide and monochloro-methyl ether (C. 1908, 
 I. 716). The ethyl ether boils at 185. The benzyl ether (A. 241, 374) 
 (C 6 H 5 CH 2 ) 2 O, boiling at 296, results from the action of boron trioxide 
 upon benzyl alcohol. Methylene-dibenzyl ether CH 2 (OCH 2 .C 6 H 6 ) 2 
 (A. 240, 200). Benzyl-arabinoside C 5 H 9 O 5 .CH 2 .C 6 H 5 melts at 172 
 (B. 27, 2482). Benzyl-phenyl ether melts at 39 and boils at 287. 
 
 Homologous Phenyl-alkyl Chlorides. a-Chlorethyl benzol C 6 H 5 CHC1. 
 CH 3 boils at 194 ; cp. B. 39, 2209. (co-) -Chlorethyl benzol C 6 H 6 . 
 CH 2 .CH 2 C1, boils at 93 (17 mm.), o-, m-, p-Methyl-benzyl chloride 
 CH 3 .C 6 H 4 CH 2 C1 boil at 198, 195, and 192 respectively. a-Chloro- 
 propyl benzol C 6 H 5 .CHC1.CH 2 .CH 3 and j3-chloro-propyl benzol C 6 H 5 . 
 CH 2 CHC1CH 3 boil about 203-2O7, with the splitting off of hydro- 
 chloric acid and the production of a-phenyl-propylene C 6 H 5 .CH : 
 CH.CH 3 and allyl benzol C 6 H 6 CH 2 CH=CH 2 ^-Bromo-propyl benzol 
 C 6 H 6 CH 2 .CH 2 .CH 2 Br, b.p. u 109 (B. 43, 178). 
 
 Benzyl phosphates : the mono- melts at 78, the di- is liquid, and 
 the tri- melts at 64 (A. 262, 211). Benzyl-sulphuric acid C 6 H 5 CH 2 . 
 OSO 3 H, formed besides dibenzyl formal CH 2 (OCH 2 C 6 H 5 ) 2 from benzyl 
 alcohol and methylene sulphate SO 4 : CH 2 (C. 1900, I. 101, 249). 
 Benzyl nitrite C 6 H 5 CH 2 ONO, b.p. 35 81, from benzyl alcohol and HNO 2 
 in aqueous solution (B. 34, 755). 
 
 Esters of Carboxylic Acid. Benzyl acetate C 6 H 5 CH 2 .O.CO.CH 3 , b.p. 
 216. The action of sodium upon the benzyl esters of the fatty acids 
 is peculiar, and tends to the formation of benzyl esters of higher phenyl 
 fatty acids (q.v.). Benzyl acetate yields phenyl-propionic benzyl ester. 
 
2 4 4 ORGANIC CHEMISTRY 
 
 Dibenzyl oxalate (C 6 H 5 .CH 2 O.CO) 2 melts at 80. 
 
 SULPHUR DERIVATIVES OF BENZYL ALCOHOL are formed just like 
 the sulphur compounds of the fatty alcohols. 
 
 Benzyl sulphydrate, benzyl mercaptan C 6 H 5 .CH 2 .SH. It is a liquid 
 with a leek-like odour ; boils at 194, and at 20 has a specific gravity 
 -1-058 (A. 140, 86). 
 
 Benzyl disulphide (C 6 H 5 CH 2 ) 2 S 2 , m.p. 71 (B. 20, 15), results from 
 the oxidation of benzyl sulphydrate in the air (A. 136, 86). Also from 
 sodium-benzyl hyposulphite by electrolysis (C. 1908, I. 1173), or by 
 the action of iodine (C. 1909, II. 1739). 
 
 Benzyl sulphide (C 6 H 5 .CH 2 ) 2 S, m.p. 49, when subjected to dry 
 distillation yields stilbene (q.v.), stilbene sulphide, dibenzyl (q.v.), 
 thionessal or tetraphenyl-thiophene (q.v.), and toluol. The sulphone 
 (C 6 H 5 .CH 2 ) 2 SO 2 , m.p. 150. It results when the sulphoxide in glacial 
 acetic acid is acted upon by KMnO 4 (B. 13, 1284 ; 36, 534). 
 
 Benzyl-dimethyl-sulphine iodide C 6 H 5 CH 2 S(CH 3 ) 2 I is an orange-red 
 coloured compound (B. 7, 1274). 
 
 Tribenzyl-sulphinic chloride (C 6 H 5 CH 2 ) 3 SC1. The ferric chloride 
 double salt is obtained in the form of light-green flakes, of m.p. 98, 
 by the action of ferric chloride upon an etheric solution of benzyl 
 chloride and benzyl sulphide. Tribenzyl-sulphinic iodide, m.p. 75 
 (B. 40, 4932). 
 
 Benzyl sulphoxide (C 6 H 5 CH 2 ) 2 SO, m.p. 133, is formed by oxidising 
 benzyl sulphide with nitric acid (B. 13, 1284). Benzyl sulphone 
 (C 6 H 5 CH 2 ) 2 SO 2 , m.p. 150, from benzyl sulphoxide with MnO^K in 
 glacial acetic acid (B. 13, 1284). Benzyl disulphoxide C 6 H 5 CH 2 
 SOSOCH 2 C 6 H 5 , m.p. 108, from benzyl disulphide and H 2 O 2 . 
 
 Methyl- and ethyl-benzyl sulphone, m.p. 127 and 84, from sodium- 
 benzyl sulphinate and CH 3 I and C 2 H 5 I respectively (B. 39, 3315). 
 
 Benzyl-sulphinic acid C 6 H 6 CH 2 SO 2 H, obtained by the reduction 
 of benzyl sulpho-chloride. It easily splits into benzaldehyde and 
 sulphurous acid (B. 39, 3308). 
 
 Benzyl-sul phonic acid C 6 H 6 .CH 2 .SO 3 H is a deliquescent crystalline 
 mass ; it is isomeric with toluol-sulphonic acid. The potassium salt 
 is formed on boiling benzyl chloride with potassium sulphite. The 
 chloride melts at 92 (B. 13, 1287). 
 
 Benzyl-hyposulphurous acid C 6 H 6 CH 2 SSO 3 H, m.p. 74 (B. 23, 
 R. 284). 
 
 NITROGEN DERIVATIVES OF THE PHENYL-PARAFFIN ALCOHOLS. 
 
 PHENYL-NITRO-PARAFFINS. When the homologous benzols are 
 heated in sealed tubes with dilute nitric acid, the nitro-groups usually 
 enter the side chains with the formation of phenyl-nitro-paraffins 
 (Konowaloff, B. 28, 1850, R. 235 ; 29, 2199 ; C. 1899, I. 1237). 
 
 By this treatment toluol yields phenyl-nitro-methane C 6 H 5 .CH 2 .NO 2 . 
 This body has also been prepared from nitro-benzal-phthalide, as well 
 as from benzyl haloids, but best from the iodide (B. 29, 700) by the 
 action of silver nitrite. It is an oil, boiling with decomposition at 
 226. It is most easily obtained from phenyl-nitro-aceto-nitrile 
 C 6 H 5 CH(NO 2 )CN (q.v.) by boiling with NaHO, or by the action of 
 ethyl nitrate and potassium ethylate upon phenyl-acetic ester, a reaction 
 
DERIVATIVES OF PHENYL-PARAFFIN ALCOHOLS 245 
 
 in which the carbox-ethyl group is split off in the form of carbonic 
 acid ester (B. 42, 1930). On heating with NaHO to 160 the phenyl- 
 nitro-methane is further changed, nitrogen oxides being split off and 
 stilbene formed (B. 36, 1194 ; 38, 502). 
 
 Phenyl-nitro-methane dissolves, like the nitre-paraffins (Vol. I.), in 
 sodium hydroxide, forming a sodium salt, from which the oily phenyl- 
 nitro-methane is regained by the action of CO 2 or acetic acid. If, 
 however, the sodium salt be precipitated with mineral acids, a crystal- 
 line substance, m.p. 84, is obtained. This is isomeric with the oily 
 body, and is distinguished from it by the red coloration it yields with 
 ferric chloride, as well as by its electric conductivity. It quickly 
 changes, both in solution and when in a free state, into the oily isomeride. 
 Its constitution certainly corresponds to the formula adopted for the 
 sodium salts of the nitro-paramns, from which, however, the correspond- 
 ing free bodies in the fatty series have not been successfully isolated 
 (Hantzsch and O. W. Schultze, B. 29, 2251) : 
 
 C 8 H 5 CH 2 N< , c 6 H 5 .CH : N^ > C,H 5 CH : 
 
 Similar stable and unstable isomerides have also been obtained from 
 the nucleus homologues and substituted phenyl-nitro-parafBns (B. 29, 
 2193, 2253, R. 40). 
 
 The action of acid chlorides upon the sodium salts of the phenyl- 
 nitro-methanes usually gives acyl derivatives of benzo-hydroxamic 
 acid, in consequence of an intramolecular oxidation process ; sodium 
 phenyl-nitro-methane and acetyl chloride give aceto-benzo-hydroxamic 
 acidC 6 HgC(OCOCH 3 )NOH (C. 1900, I. 177). On ammonium salts of 
 phenyl-nitro-methane, see C. 1900^ I. 1092. 
 
 Tolyl-nitro-methane, see B. 38, 503 ; C. 1905, II. 817. co-Nitro- 
 durol (CH 3 ) 3 [2, 4, 5]C 6 H 2 [i]CH 2 NO 2 , m.p. 52 ; iso-nitro-compound, 
 m.p. I02-io6, is easily obtained by nitrogenation of durol with benzoyl 
 nitrate (B. 42, 4154). 
 
 Phenyl-methyl-nitro-methane C 6 H 5 CH(CH 3 )NO 2 , b.p. 115, from 
 aceto-phenone monoxime (q.v.) by oxidation with Caro's acid ; the 
 corresponding unstable nitronic acid C 6 H 5 C(CH 3 ) : NOOH melts about 
 45 (B. 36, 706). 
 
 Phenyl-paraffin Amines, Benzyl-amines. (i) Alcoholic ammonia 
 converts benzyl chloride into mono-, di-, and tribenzy I- amines (B. 23, 
 2971 : C. 1901, II. 1155). 
 
 Most of the other methods of producing benzyl-amine are reactions 
 which have been fully discussed in connection with the primary 
 alkyl-amines. 
 
 Benzyl-amine is formed (2) by the reduction of phenyl-nitro-methane, 
 benzaldoxime, and benzylidene-phenyl-hydrazone (B. 19, 1928 ; 35, 
 1513 ; 42, 1559) '> (3) an d (4) by heating benzaldehyde with ammonium 
 formate or formamide (B. 19, 2128 ; 20, 104 ; A. 343, 54), together 
 with di- and tribenzyl-amine ; (5) by the reduction of benzo-nitrile 
 (B. 20, 1709) and (6) of benzo-thiamide (B. 21, 51) ; (7) of benzamide 
 (C. 1899, II. 623) ; (8) by saponifying benzyl iso-cyanide or benzyl 
 carbon-imide C 6 H 5 CH 2 NCO (B. 5, 692), and (9) benzyl acetamide 
 C 6 H 5 CH 2 NHCOCH 3 (B. 12, 1297) ; (to) by the distillation of the 
 
246 ORGANIC CHEMISTRY 
 
 phenyl-amido-acetic acid C 6 H 5 CH(NH 2 )CO 2 H (B. 14, 1969) ; and (n) 
 by the action of caustic alkali and bromine upon phenyl-acetic amide. 
 Benzyl-amine is a liquid, dissolving readily in water. It differs from 
 its isomeric toluidin in being a strong base, which attracts CO 2 from 
 the air. 
 
 Caro's acid oxidises benzyl-amine to benzaldoxime, phenyl-nitro- 
 methane, and benzo-hydroxamic acid, besides benzaldehyde and 
 benzoic acid (B. 34, 2262). 
 
 Dibenzyl-amine (C 6 H 5 CH 2 ) 2 NH, b.p. 300, is also obtained from 
 benzalazin C 6 H 5 CH : N.N : CHC 6 H 5 by reduction with zinc dust and 
 acetic acid, and (with benzyl-amine) by reduction of benzo-nitrile. 
 
 Nitroso-dibenzyl-amine (C 6 H 5 CH 2 ) 2 NNO, m.p. 61 (B. 34, 557). 
 
 Tribenzyl-amine (C 6 H 6 CH 2 ) 3 N, m.p. 91. 
 
 Homologous benzyl-amines are isomeric with corresponding alphyl- 
 amines. They are mostly formed by reducing nitriles with alcohol and 
 sodium ; some by the reduction of oximes or nitro-compounds, while 
 others are obtained by the methods indicated under benzyl-amine. 
 
 /3-Phenyl-ethyl-amine . . C 6 H 5 CH 2 CH 2 NH 2 b.p. 197 
 
 a-Phenyl-ethyl-amine . . C 6 H 5 CH(NH 2 )CH 3 187 
 
 y-Phenyl-propyl-amine . . C 8 H 5 .CH 2 .CH 2 CH 2 NH 2 221 
 
 0-Phenyl-propyl-amine . . C 6 H 5 CH(CH 3 ).CH 2 NH 2 210 
 
 a-Phenyl-propyl-amine . . C 6 H 5 CH(NH 2 ).CH 2 .CH 3 205 
 
 0-Phenyl-iso-propyl-amine . C 6 H 5 CH 2 .CH(NH 2 )CH 3 ,, 203 
 
 o-Tolu-benzyl-amine . . CH 3 [2]C 6 H 4 [i]CH 2 NH 2 205 
 
 m-Tolu-benzyl-amine . . CH 3 [ 3 ]C 6 H 4 [i]CH 2 NH 2 201 ' 
 
 p-Tolu-benzyl-amine . . CH 3 [ 4 ]C 6 H 4 [i]CH 2 NH 3 195 
 
 co-Pseudo-cumyl-amine . . (CH 3 ) 2 [2, 4 ]C 6 H 3 [i]CH 2 NH 2 218 
 
 co-Mesityl-amine . . . (CH 3 ) 2 [ 3> 5 ]C 6 H 3 [i]CH 2 NH 2 221" 
 
 co-Duryl-amine . . . (CH 3 ) 3 [2, 4 , 5 ]C 6 H 2 [i]CH 2 NH 2 m.p. 52 " 
 
 Cumyl-amine . (CH 3 ) 2 CH[ 4 ]C 6 H 4 [i]CH 2 NH 2 b.p. 226 
 
 Cumo-benzyl-amine . . ' (CH 3 ) 3 [2, 4 , 5]C 6 H 2 [i]CH 2 NH 2 m.p. 6 4 13 
 
 Hemimelli-benzyl-amine . (CH 3 ) 3 ] 3 , 4 , 5 ]C 6 H 2 [i]CH 2 NH 2 123" 
 
 Literature. 1 B. 26, 1904 ; 2 B. 27, 2306 ; 3 B. 27, 2309 ; * B. 26, 2875 ; 
 
 * B 20, 618 ; 8 B. 23, 1026 ; 33, 1013 ; C. 1899, I. 1238 ; 7 B. 23, 3165 ; 8 B. 20, 
 
 1719; B. 21, 3083; 10 C. 1899, I. 1238; B. 42, 4 i56; 12 B. 20, 2414; 
 13 B. 24, 2 4 o 9 ; " B. 24,2411. 
 
 a-Phenyl-ethyl-amine C 6 H i CH(NH 2 )CH 3 is obtained by electrolytic 
 reduction of aceto-phenone oxime (B. 35, 1515) ; it contains an un- 
 symmetrical C atom, and has been split up into its optically active 
 components by means of its maleic salt (C. 1899, II. 1123 ; 1905 II 
 
 1583). 
 
 The pure benzyl-amines are associated with benzyl-alkyi- and 
 benzyl-aryl-amines, as well as benzyl-alkyl-ammonium compounds. 
 Benzyl-alkyl-amines, like benzyl-ethyl-amine C 6 H 5 .CH 2 NHC 2 H 5 , and 
 cumyl-ethyl-amine C 3 H 7 C 6 H 4 CH 2 NHC 2 H 5 , are obtained from the cor- 
 responding benzylidene-alkyl-amines by reduction with Na and alcohol, 
 or by heating benzaldehyde with organic formates (B. 35, 410 A! 
 343, 54). Dibenzyl-ethylene-diamine (C 6 H 5 CH 2 NH) 2 C 2 H 4 , b.p. 175- 
 182, from dibenzylidene-ethylene-diamine ; it condenses with ethylene 
 bromide to dibenzyl-piperazin (C. 1898, II. 743). Pheno-propyl-methyl- 
 amine C 6 H 5 CH 2 CH 2 CH 2 NHCH 3 , b.p. 18 134, is obtained from cin- 
 
DERIVATIVES OF PHENYL-PARAFFIN ALCOHOLS 247 
 
 namylidene-methyl-amine C 6 H 5 CH : CH.CH : NCH 3 with sodium and 
 alcohol (C. 1902, I. 662). a-Phenyl-ethyl-methyl-amine C 6 H 5 (CH 3 ) 
 CHNHCH 3 , b.p. ls 87, and a-phenyl-propyl-methyl-amine, b.p.^ 96, 
 are obtained by the action of methyl- and ethyl-magnesium iodide 
 respectively upon benzal-methyl-amine (/. pr. Ch. 2, 77, 20). 
 
 Benzyl - phenyl - allyl - methyl - ammonium iodide (C 6 H 5 CH 2 ) (CgHg) 
 (C 3 H 5 )(CH 3 )NI contains an unsymmetrical N atom, and has been split 
 up into optically active components by means of campho-sulphonic 
 acid (B. 32, 3561 ; C. 1901, II. 206). Similarly, the splitting up of many 
 other quaternary benzyl-ammonium compounds, with four different 
 radicles, has been accomplished (see E. Wedekind, Stereo-chemistry 
 of Qiiinquevalent Nitrogen, Leipzig, 1907). 
 
 Benzyl-aniline C 6 H 5 .CH 2 .NH.C 6 H 5 melts at 32, and is formed from 
 aniline and benzyl chloride (A. 138, 225), or by the reduction of 
 benzylidene-aniline with sodium in alcoholic solution (A. 241, 330), or 
 by electrolytic reduction (B. 42, 3460). When heated to 220 with 
 sulphur it yields thio-benzanilide, and benzenyl-amido-thio-phenol at 250 
 (A. 259, 300). For acid derivatives of benzyl -aniline, see B. 32, 2672. 
 
 Dibenzyl-aniline (C ? H 5 .CH 2 ) 2 .N.C 6 H 5 , m.p. 67 (B. 20, 1611). 
 
 C-alkyl-benzyl-anilines like C6H 5 CH(CH 3 )NHC 6 H 5 are produced 
 by the attachment of alkyl-magnesium haloids to benzal-aniline : 
 
 C 6 H 5 CH : NC 6 H 5 5l?_$! C fl H 6 CH(CH 3 ).N(MgI)C,H 5 J^ C a H 5 CH(CH 3 )NHC 8 H 5 . 
 
 The chlorohydrates of these bases, when heated to 220 with aniline 
 chlorohydrate, undergo an atomic displacement analogous to Hof- 
 mann's transposition, with formation of C-alkyl-p-amido-diphenyl- 
 methanes, e.g. 
 
 C 6 H 5 CH(CH 3 )NHC 6 H 5 > NH 2 C 6 H 4 CH(CH 3 )C 6 H 6 . 
 
 C-Methyl-, -ethyl-, -propyl-, and -amyl-benzyl-aniline, b.p. 20 183, 
 192, 200, and 215 (B. 38, 1761). 
 
 Benzyl-oxethyl-amine C 6 H 5 .CH 2 .NH.CH 2 .CH 2 OH, picrate, melt- 
 ing at 136, results from the rupture of the phenyl-oxazolin ring 
 
 C 6 H 5 .C/;^ 2 by sodium and alcohol (B. 29, 2382). 
 
 The following representatives of the numerous benzylated acid 
 amides and benzylated nitrogen derivatives of carbonic acid may be 
 mentioned : 
 
 Benzyl acetamide C 6 H 5 CH 2 NHCOCH 3 , m.p. 60 (B. 19, 1286). Its 
 nitroso-derivative C 6 H 5 CH 2 N(NO)COCH 3 is decomposed by alcohols 
 with elimination of nitrogen, and formation of benzyl-alkyl ethers ; 
 this decomposition, recalling the diazo-bodies, is also shown by other 
 nitrosated acid derivatives of benzyl- amine (B. 31, 2640 ; 32, 78). 
 
 Dibenzyl-urea chloride (C 6 H 5 CH 2 ) 2 NCOC1 is an oil (B. 25, 1819). 
 Benzyl-urethane C 6 H 5 CH 2 NHCO 2 C 2 H 5 , m.p. 44. 
 
 Benzyl-urea C 6 H 5 CH 2 NHCONH 2 , m.p. 147. Sym. and unsym. 
 di-benzyl-urea melt at 167 and 124 (B. 9, 81). Tri- and tetrabenzyl- 
 urea melt at 119 and 85 (B. 25, 1826). 
 
 Benzyl-thio-urea melts at 164 (B. 24, 2727 ; 25, 817). 
 
 Dibenzyl-guanidin (C 6 H 5 CH 2 NH) 2 C : NH, m.p. 100 (B. 5, 695). 
 
 Benzyl iso-eyanate, benzyl carbonimide C 6 H 5 CH 2 N : CO, is a liquid 
 with a penetrating odour. Benzyl cyanurate melts at 157 (B. 5, 692). 
 
248 ORGANIC CHEMISTRY 
 
 Benzyl-mustard oil C 6 H 5 CH 2 N : CS, b.p. 243, forms the chief in- 
 gredient of the ethereal oils of various cresses (B. 32, 2336). 
 
 BENZYL -HYDRAZINS. Benzyl - hydrazin C 6 H 5 CH 2 NH.NH 2 , b.p. 41 
 103, is obtained by decomposition of its benzylidene compound 
 C 6 H 5 CH 2 NH.N : CHC 6 H 5 with acids. This compound is obtained by 
 a partial reduction of benzal-azin with Na amalgam and alcohol. With 
 HNO 2 , benzyl-hydrazin gives a very stable nitroso-compound C 6 H 5 CH 2 N 
 (NO)NH 2 , m.p. 71 (B. 33, 2736). 
 
 Unsym. dibenzyl-hydrazin (C 6 H 5 CH 2 ) 2 N.NH 2 , m.p. 65, from benzyl 
 chloride with hydrazin hydrate ; also from dibenzyl nitrosamine by 
 reduction with zinc dust and acetic acid ; by oxidation with HgO it 
 yields a tetrazone, m.p. 97 ; but under other conditions nitrogen 
 seems to be liberated, with the formation of dibenzyl (B. 33, 2701 ; 
 34,552). 
 
 Sym. benzyl-phenyl-hydrazin C 6 H 5 CH 2 NHNHC 6 H 5 , m.p. 35, b.p. 
 about 290, is obtained by the reduction of benzal-phenyl-hydrazone 
 with Na amalgam in alkaline solution. Oxidation in air readily re- 
 converts it into the phenyl-hydrazone (/. pr. Ch. 2, 78, 49). Unsym. 
 benzyl-phenyl-hydrazin C 6 H 5 CH 2 N(C 6 H 5 )NH 2 , m.p. 26, from phenyl- 
 hydrazin and benzyl chloride, is suitable for separating sugars in the 
 form of hydrazones (B. 32, 3234 ; C. 1904, II. 1293). On oxidation it 
 passes into dibenzyl - diphenyl - tetrazone C 6 H 5 CH 2 (C 6 H 5 )N.N : N.N 
 (C 6 H 5 )CH 2 C 6 H 5 , m.p. 145, which on heating in xylene solution de- 
 composes into Na and sym. dibenzyl-diphenyl-hydrazin, b.p. 22 181 
 (B. 39, 2566). 
 
 BENZYL-DIAZOCOMPOUNDS. BENZYL-TRIAZENES. BENZYL-AZIDES. 
 
 Potassium-benzyl diazotate C 6 H 5 CH 2 N : NOK (?) is obtained by 
 the action of highly concentrated potash lye upon nitroso-benzyl- 
 urethane C 6 H 5 CH 2 N(NO)CO 2 C 2 H 5 . It forms a white crystalline 
 powder, which, on wetting with water, splits up into KOH and phenyl- 
 
 N 
 
 diazo-methane C 6 H-CH/ 1| ; the latter is a reddish-brown oil, which, 
 
 N . 
 on distillation, breaks up into nitrogen and stilbene C 6 H 5 CH : CHC 6 H 5 ; 
 
 on warming with water, into N 2 and benzyl alcohol ; with alcohol, 
 into N 2 and benzyl ether ; and with HC1, into N a and benzyl chloride 
 (B. 35, 903 ; cp. also Diazo-methane, Vol. I.). 
 
 Sodium-benzyl iso-azotate C 6 H 5 CH 2 .N : NONa, colourless needles, 
 is formed by the action of ethyl nitrite and sodium methylate upon 
 unsym. nitroso-phenyl-hydrazin, with simultaneous liberation of nitrous 
 oxide. It differs decidedly from the corresponding K salt. In cold 
 water it dissolves unchanged, but on heating, or with dilute acids, it 
 decomposes into N 2 and benzyl alcohol. On reduction it passes into 
 benzyl-hydrazin ; on oxidation, into benzyl-nitramine C 6 H 5 CH 2 NHNO 2 
 m -P- 39> from which it may be recovered by reduction with aluminium 
 and soda (A. 376, 255). 
 
 Benzyl-methyl-triazene C 6 H 5 CH 2 N : N.NHCH 3 , a colourless oil, 
 resembling in its instability the aliphatic diazo-amido-compounds 
 (Vol. I.), and readily decomposed even by CO 2 . Obtained from ben- 
 zyl azide and CH 3 MgI. The cupro-salt melts at 114, and consists of 
 pale-yellow grains ; silver salt, m.p. 125, colourless needles (B. 38, 684). 
 
BENZYL-HYDROXYLAMINES 249 
 
 Benzyl-phenyl-triazene C 6 H 5 CH 2 NH.N : NC ? H 5 or C 6 H 5 CH 2 N : 
 N.NHC 6 H 5 , m.p. 75, colourless flakes, is obtained by transforming 
 benzyl azide with C 6 H 5 MgBr, or phenyl azide with C 6 H 5 CH 2 MgCl. 
 Dilute HC1 splits it up into benzyl chloride, aniline chlorohydrate, 
 and nitrogen (B. 38, 682). 
 
 Benzyl-azide C 6 H 5 CH 2 N<, b.p. n 74, from C 6 H 5 CH 2 N< 2 , benzyl- 
 
 nitroso-hydrazin, on boiling with dilute H 2 SO 4 , or from benzyl iodide 
 with silver nitride, is a very stable ether of nitro-hydric acid ; it is 
 only decomposed by fairly concentrated H 2 SO 4 , yielding, with liberation 
 of N, (i) benzaldehyde and NH 3 ; (2) formaldehyde and aniline ; (3) 
 benzyl-amine and N 2 O (?) ; or (4) benzyl alcohol (and NH 3 ) (/. pr. Ch. 
 2, 63, 428 ; B. 35, 3229). 
 
 Benzyl-hydroxylamines. a-Benzyl-hydroxylamine, b.p. 5n 123, best 
 obtained by splitting up benzyl acetoxime C 6 H 5 CH 2 ON : C(CH 3 ) 2 
 with HC1 ; in a similar manner a, p-ehloro-benzyl-hydroxylamine, m.p. 
 38, b.p. 17 128, and a, p-bromo-benzyl-hydroxylamine, m.p. 37, b.p. 10 
 133, have been prepared. The a-benzyl-hydroxylamine, on heating 
 in a pressure tube, breaks up, partly into NH 3 , water, and benzal- 
 doxime-benzyl ether. With SOC1 2 it yields thionyl-benzyl-hydroxyl- 
 amine C 6 H 5 CH 2 ON : SO, b.p. 50 154 ; with COC1 2 , dibenzyl-oxy-urea 
 (C 6 H 5 CH 2 ONH) 2 CO, m.p. 88; with formimido-ether chlorohydrate, 
 dibenzyl-formo-hydroxamoxime C 8 H 5 CH 2 ONH.CH : NOCH 2 C 6 H 5 , m.p. 
 42 (B. 26, 2155 ; 33, 1975). Treated with benzyl chloride, the 
 a-benzyl-hydroxylamine passes into aj8-dibenzyl - hydroxylamine 
 C 6 H 5 CH 2 O.NHCH 2 C 6 H 5 , a liquid, and tribenzyl-hydroxylamine C 6 H 5 
 CH 2 ON(CH 2 C 6 H 5 ) 2 , liquid. The former, split up with HC1, gives 
 0-benzyl-hydroxylamine C 6 H 5 CH 2 .NHOH, m.p. 57, which, with benzyl 
 chloride, yields jS-dibenzyl-hydroxylamine (C 6 H 5 CH 2 ) 2 NOH, m.p. 123 
 (A. 275, 133). The jS-benzyl-hydroxylamine combines with aldehydes to 
 form N-benzyl-aldoximes . With oxidisers, like bromine water or chromic 
 acid, it is converted mainly into bis-nitroso-benzyl (C 6 H 5 CH 2 NO) 2 . 
 The latter is converted by HC1 into benzal-benzoyl-hydrazin and its 
 disintegration product : 
 
 (C 6 H 5 CH 2 NO) 2 --- > C 6 H 5 CH : N.NHCOC 6 H 5 +H 2 O. 
 
 Atmospheric oxygen produces mainly benzaldoxime (B. 33, 3193 ; 
 A. 323, 265). Oxidation of the j3-dibenzyl-hydroxylamine produces 
 N-benzyl-benzaldoxime. 
 
 Substituted benzyl alcohols are derived from substituted benzyl 
 chlorides when they are heated with aqueous potash (B. 25, 3290), or 
 by means of acetic esters. Many, like m-nitro-benzyl alcohol, are also 
 obtained by the action of alcoholic potash upon the corresponding 
 aldehydes. They have also been prepared by the electrolytic reduc- 
 tion of substituted benzoic acids. 
 
 Ortho- Meta- Para- 
 
 Chloro-benzyl alcohol . . m.p. 72 liquid 73 
 
 Bromo-benzyl alcohol . . 80 72 
 
 Bromo-benzyl bromide . . ,, 30 41 61 
 
 Nitro-benzyl alcohol . . 74 27 93 
 
 Nitro-benzyl chloride . . 47 46 71 
 
250 ORGANIC CHEMISTRY 
 
 o-Nitro-benzyl alcohol results also from the electrolytic oxidation 
 of o-nitro-toluol (C. 1901, II. 1051) ; and p-nitro-benzyl alcohol by 
 oxidation of p-nitro-toluol with MnO 2 and concentrated SO 4 H 2 
 (German patent 212,949). The o-nitro-benzyl alcohol is reduced 
 by zinc dust and sal-ammoniac solution to o-hydroxylamino-benzyl 
 alcohol HONH[2]C 6 H 4 CH 2 OH, m.p. 104, which is oxidised by 
 chromic acid to azoxy-benzyl alcohol ON 2 (C 6 H 4 CH 2 OH) 2 , m.p. 123 ; 
 and by Caro's acid or ferric chloride to o-nitroso-benzyl alcohol 
 ON[2]C 6 H 4 CH 2 OH, m.p. 101. The latter, on being boiled in water, 
 loses H 2 O and passes into anthranile (B. 36, 836), and forms the link in 
 the transition of o-nitro-toluol into anthranilic acid on heating with 
 alkaline hydroxide. 
 
 Reduction of the nitro-benzyl alcohols, as well as the electrolytic 
 reduction of nitro- and amido-benzoic acids in acid solution, produce 
 amido-benzyl alcohols. p-Amido-benzyl alcohol, m.p. 64 (A. 305, 119), 
 
 * /~T_T 
 
 is converted by acids into an anhydro-lorm ^C e H 4 <^ | ), which is 
 
 also obtained, with other derivatives, by direct action of formaldehyde 
 upon the corresponding anilines in the presence of acids (B. 31, 2037 ; 
 33, 250 ; 35, 739 ; C. 1898, II. 159 ; Ch. Ztg. 24, 284). 
 
 p-Amido-benzyl-amine NH 2 C 6 H 4 CH 2 NH 2 b.p. 269 ; p-Acetyl- 
 amido-N-ehloracetyl-benzyl-amine CH 3 CONHC 6 H 4 CH 2 NHCOCH 2 C1 is 
 produced by nuclear synthesis in the condensation of acetanilide 
 with methylol-chloracetamide CH 2 C1CONH.CH 2 OH under the action 
 of concentrated H 2 SO 4 . On boiling with HC1 the acetyl and chlor- 
 acetyl groups are split off (A. 343, 299). 
 
 p-Amido-benzyl-aniline NH 2 C 6 H 4 CH 2 NHC 6 H5 a viscous oil, from 
 anhydro-formaldehyde-aniline with aniline ; easily transposed to di- 
 amido-diphenyl-methane (B. 29, R. 746 ; C. 1900, I. 1112). p-Nitro- 
 benzyl-amine, see B. 30, 61. 
 
 m-Amido-benzyl alcohol NH 2 [3]C 6 H 4 [i]CH 2 OH, m.p. 92, from 
 m-nitro-benzoic acid by electrolytic reduction (B. 38, 1751). 
 
 o-Amido-benzyl alcohol NH 2 [2]C 6 H 4 CH 2 OH, m.p. 82, b.p. 10 160, 
 is formed from o-nitro-benzyl alcohol or from anthranile by reduction 
 with zinc dust and HC1 (B. 25, 2968 ; 27, 3513) ; from anthranilic 
 ester with Na amalgam in acid solution (B. 38, 2062) ; and by 
 electrolytic reduction of o-nitro-benzoic acid or anthranilic acid 
 (B. 38, 1751). 
 
 0-Acetyl-o-amido-benzyl alcohol NH 2 C 6 H 4 CH 2 OCOCH 3 , an oil 
 smelling of aniline, with a chlorohydrate melting at 116, is formed by 
 the reduction of o-nitro-benzyl acetate. The free base is unstable, 
 and on standing, or (rapidly) on heating, it passes into the crystalline 
 N-acetate CH 3 CONHC 6 H 4 CH 2 OH, m.p. 116. Cold HBr converts the 
 latter into the bromohydrate of /x-methyl-pheno-pentoxazol, which, 
 on standing in water, takes up water and splits up to form O-acetyl- 
 o-amido-benzyl alcohol (B. 37, 2249). 
 
 Formation of Hetero-rings from Derivatives of o-Amido-benzyl 
 Alcohol. Just like the o-diamines, o-amido-phenols, and o-amido- 
 thio-phenols, many o-amido-benzyl alcohol derivatives, and also those 
 of o-nitro-benzyl alcohol, so far as they yield o-amido-benzyl alcohol 
 compounds upon reduction, show ability to form hetero-rings. Some 
 
DERIVATIVES OF O-AMIDO-BENZYL ALCOHOL 251 
 
 of the derivatives of these two alcohols capable of yielding hetero-rings 
 are the following : 
 
 o-Amido-benzyl alcohol combines with nitroso-benzol to o-benzol- 
 azo-benzyl alcohol C 6 H 5 N : NCgH 4 CH 2 OH, m.p. 78, which, on heating 
 with H 2 SO 4 , becomes phenyl-indazol (C. 1903, I. 1416). It becomes 
 thio-cumazone (B. 27, 1866) when it is boiled with alcoholic CS 2 , and 
 thio-cumo-thiazone (B. 27, 2427) when the CS 2 and alcoholic potash are 
 used. The urea derivatives of o-amido-benzyl alcohol lead to similar 
 rings (B. 27, 2413). 
 
 o-Nitro-benzyl sulpho-cyanide NO 2 C 6 H 4 CH 2 S.CN, m.p. 75 (B. 25, 
 3028), yields o-benzylene-0-thio-urea. Sulphuric acid reduces it to 
 o-nitro-benzyl-carbamine-thiolic ester NO 2 .C 6 H 4 CH 2 .SCONH 2 , m.p. 
 116. Hydrochloric acid saponifies this to o-nitro-benzyl mereaptan 
 NO 2 [2]C 6 H 4 [i]CH 2 SH, m.p. 43. Both bodies yield benz-iso-thiazol 
 upon reduction (B. 28, 1027 ; 29, 160). 
 
 o-Amido-benzyl chloride hydrochloride HC1.NH 2 .C 6 H 4 CH 2 C1 is 
 formed by the action of concentrated hydrochloric acid upon o-amido- 
 benzyl alcohol. With caustic potash this yields poly-o-benzylene- 
 imide (C 7 H 7 N) X (B. 19, 1611 ; 28, 918, 1651) ; with acetic anhydride, 
 H-methyl-pheno-pentoxazol ; with thiacetamide, ^-methyl-pheno-penthi- 
 azol (B. 27, 3515) ; and with thio-urea, o-benzylene-ip-thio-urea (B. 28, 
 1039) : 
 
 C.H 4 j 2 - ~ H2 > C,H 4 < - ^>NC 4 H 8 Phenyl-indazol (i) 
 
 ( CH.OH I ~ ^ -* C ' H *{ NH^S Thio-cumazone (a) 
 
 * t NH a [ CS.KOH ^ QH4 1 CH,^ Thio . cumo . thiazone (3) 
 
 f CH 2 SCN H 
 
 9 *1 NO, \ c H ( CH, S ( CH, S 
 
 j CH.C1 -f Thio-carbamide J * * ( NH C : NH C ( N=C.NH, 
 
 1 NH'HCI o-Benzylene-^-thio-urea 
 
 Benz-iso-thiazol (5) 
 JT ,.Me t h yI -phen -pentoxazol( 6 ) 
 
 +Thiacetamide M-Methyl-pheno-penthiazol (7). 
 
 The anhydride of an o-benzyl-alcohol-sulphonic acid, sulpho-benzide 
 
 C 6 H 4{[2]CH 2 2 ) >O ' m - p - II3 ' is obtamed b Y tne reduction of the stable 
 o-sulpho-benzoic acid chloride, much as the phthalide is obtained from 
 phthalyl chloride ; also by reduction of the product of the action of 
 PC1 5 upon o-benzaldehyde-sulphonic acid (B. 31, 1666). 
 
 o-Nitro-benzyl-amine C 6 H 4 (N0 2 ).CH 2 .NH 2 , obtained from o-nitro- 
 benzyl chloride by the saponification of its phthalimide derivative, is 
 a strong, oily base (B. 20, 2227). 
 
 o-Nitro-benzyl-formamide NO 2 .C 6 H 4 .CH 2 .NH.CHO, melting at 89, 
 is reduced to dihydro-quinazolin (B. 25, 3031 ; 36, 806). 
 
 o-Nitro-benzyl-amline NO 2 .C 6 H 4 .CH 2 .NHC 6 H 5 , melts at 44 (B. 
 19, 1607). 
 
 o-Nitro-benzyl-phenyl-nitrosamme NO 2 C 6 H 4 CH 2 N(NO)C 6 H 5 is con- 
 verted by tin and hydrochloric acid into n-phenyl-indazol (B. 27, 2899), 
 
252 
 
 ORGANIC CHEMISTRY 
 
 o-Amido-benzyl-amine, o-benzylene-diamine NH 2 C 6 H 4 CH 2 NH 2 is 
 a radiating crystalline mass, obtained from o-nitro-benzyl-amine. 
 With aldehydes like benzaldehyde it forms phenyl-tetrahydro-keto- 
 quinazolin ; with phosgene, tetrahydro-keto-quinazolin ; with carbon 
 disulphide, tetrahydro-thio-quinazolin (B. 28, R. . 238). o-Amido- 
 benzyl-aniline NH 2 .C 6 H 4 .CH 2 .NH.C 6 H 5 , melting at 86, forms ]8- 
 pheno-phenyl-dihydro-triazin with nitrous acid (B. 25, 448). 
 
 r TT JCH 2 NHCHO 
 L/g.ri.,i -< * 
 4 \N0 2 
 
 CgH /CH 2 N(NO)C 6 H 5 
 
 CH 2 NH 2 
 
 H 
 
 sn 
 
 . fCH 2 NH 
 
 6 I isi ' Dihydro-quinazoli 
 
 T f CH ^ 
 / i*H J j i ^ > NC 6 H 5 n-Phenyl-indazol 
 
 - H fCH 2 NH c-Phenyl-tetrahydi 
 4 \ NH CHC 6 H 5 quinazolin 
 
 go ^^8 A1 4^ i x x>i>L, 6 n 5 n-jrnenyi-maazoi 
 
 \N 
 
 C,H 5 CHO >c H (CH 2 NH c-Phenyl-tetrahydro- 
 
 4 \ NH CHC 6 H 5 quinazolin 
 
 CQC1 2 >c H J'CH 2 NH Tetrahydro-keto-quin- 
 
 4 INH -co azolin 
 
 fCH 2 NH Tetrahydro-thio-quin- 
 [NH CS azolin 
 
 'CH 2 N.C 6 H 5 ^-Pheno-phenyl-dihydro- 
 y jj- triazin. 
 
 NOOH r TT fCH, 
 
 yC ' H HN=N 
 
 (2) AROMATIC MONALDEHYDES. 
 
 The aromatic monaldehydes are the first oxidation products, and 
 correspond to the primary aromatic monohydric alcohols. They are 
 very similar to the fatty aldehydes so far as their rearrangements, de- 
 pendent upon the reactivity of the aldehyde group, are concerned. 
 
 Formation. (i) By the oxidation of the primary monohydric, 
 aromatic alcohols. (2) By the distillation of the calcium salts of the 
 aromatic monocarboxylic acids with calcium formate. (3) From their 
 halogen derivatives C 6 H 5 .CHC1 2 , with water, especially in the presence of 
 sodium carbonate, lime, or lead oxide, or by heating with anhydrous 
 oxalic acid. (4) Technically, by oxidising benzyl chloride with lead 
 nitrate. (5) A very interesting and direct conversion of homologous 
 benzenes into aldehydes is that occurring in the action of chromyl 
 chloride CrO 2 Cl 2 . The first products are pulverulent, brown addition 
 compounds C 6 H 5 CH 3 (CrO 2 Cl 2 ) 2 , which decompose into aldehydes when 
 they are introduced into water (B. 17, 1462; 21, R. 714; 32, 1050). 
 On oxidising methyl-benzols with chromic acid in the presence of acetic 
 anhydride at o, diacetates of ortho-aldehydes are formed, e.g. NO 2 C 6 H 4 
 CH(OCOCH 3 ) 2 , C 6 H 4 [CH(OCOCH 3 ) 2 ] 2 . Manganese peroxide, cerium 
 oxide with sulphuric acid, or manganese persulphate also oxidise alkyl- 
 benzols in the cold to aromatic aldehydes (C. 1901, II. 70, 1154 ; 1906, 
 II. 1297, 1589). By electrolytic oxidation also, aldehydes can be 
 obtained from alkyl-benzols (C. 1905, II. 763). (6) During oxidation 
 of olenn-benzols with ozone, they are split at the ethylene link, with 
 formation of aldehydes (B. 37, 842, 2304 ; 41, 2751 ; A. 343, 311) : 
 
 C 6 H 5 CH 2 CH : CHCH 3 > C 6 H 5 CH 2 CHO. 
 
 (7) From the aromatic primary-secondary and primary-tertiary 
 
AROMATIC MONALDEHYDES 253 
 
 ethylene glycols, and from the corresponding ethylene oxides, by heat- 
 ing with dilute H 2 SO 4 or alone (C. 1905, II. 1628 ; B. 39, 2288) : 
 
 /\ 
 C 8 H 6 (CH 3 )COHCH 2 OH - > C 6 H 5 (CH 3 )CH.CHO < - C 6 H 5 (CH 3 )CH CH,. 
 
 The secondary-tertiary phenyl-ethylene glycols, in which phenyl 
 is held by a secondary link, yield aldehydes on displacement of the 
 phenyl group : 
 
 C,H 6 CH(OH)C(OH)(CH 3 ) 2 
 
 The formation of aldehydes from the iodo-hydrins of some olefm- 
 benzols by treatment with NO 3 Ag or HgO (C. 1907, I. 1577 ; 1909, 
 I- 1335) : 
 
 C,H 5 CH(OH).CHI.CH 3 - > OCH.CH^^ 5 
 
 also leads to the formation of aldehydes. 
 
 (8) From phenyl-nitro-methanes by reduction, and from j8-benzyl- 
 hydroxylamines by oxidation, oximes of the aromatic aldehydes are 
 obtained, and from these the aldehydes may be obtained by hydrolysis 
 (C. 1899, I. 1073). 
 
 (go) Synthetically, the aldehydes are obtained from the aromatic 
 hydrocarbons by the action of carbon monoxide and HC1 in the presence 
 of Cu 2 Cl 2 and Al chloride or bromide (A. 347, 347) : 
 
 C 6 H 6 +CO+HC1 c ^ C 6 H 5 CHO. 
 
 (96) Benzaldoximes C 6 H 5 CH : NOH are similarly produced from 
 benzene, detonating mercury C : NHgO, and Al chloride containing 
 water of crystallisation. Dry Al chloride forms chiefly nitriles (B. 
 36, 322). 
 
 (10) Aromatic aldehydes are also formed by the action of aryl- 
 magnesium haloids on excess of formic ester (B. 36, 4152 ; C. 1905, 
 I. 309 ; cp. also Ch. Ztg. 29, 667) : 
 
 C 6 H 5 CH 2 MgCl+HCOOC 2 H 5 -- > C 6 H 5 CH 2 CHO+ClMgOC 2 H 5 . 
 
 By using ortho-formic ester the corresponding acetals are obtained 
 (C. 1904, I. 509, 1077 ; B. 37, 1 86). 
 
 The formic ester can often be advantageously replaced by ethoxy- 
 methylene-aniline C 6 H 5 N : CHOC 2 H 5 . From the benzylidene-anilines 
 first formed the aldehydes are easily obtained by boiling with dilute 
 acids (C. 1906, I. 1487). 
 
 (n) The condensation products ArCHOH.CQ 3 , obtained from aryl- 
 magnesium haloids and chloral on boiling with potassium carbonate 
 solution, split up into chloroform and aldehydes (C. 1908, 1. 1388) : 
 
 C 6 H 5 MgBr cidHo^ C 6 H 5 CH(OH)CC1 3 -- > C 6 H 5 CHO+CHC1 3 . 
 
 (12) The aryl-glycidic acids obtained from aromatic ketones by 
 condensation with chloracetic ester, and Na ethylate or amide, easily 
 break up into CO 2 and aldehydes (C. 1905, I. 346 ; B. 38, 699) : 
 
 /\ 
 C,H 6 COCH 3 CH CLCO R - C 6 H 6 (CH 3 )C - CH.CO a H ~ co '-> C,H 6 (CH 3 )CH.CHO. 
 
254 ORGANIC CHEMISTRY 
 
 (13) Benzoyl-formic acid C 6 H 5 .CO.COOH and its homologues, 
 easily formed by synthesis, are converted, by heating with aniline, into 
 benzylidene-anilines, which may be readily split up into aldehydes 
 and aniline (C. 1903, I. 832, etc.). 
 
 (14) The acidyl-phenyl-glycolic esters (q.v.) and phenyl-tartronic 
 esters (cj.v.), obtained by the condensation of ajS-diketone-carboxylie 
 esters or mesoxalic esters with benzols, tertiary anilines, or phenols, 
 may be converted into the corresponding aldehydes, (I.) by warming 
 with concentrated H 2 SO 4 , or (II.) by oxidation with copper acetate 
 and decomposition of the resulting benzoyl-formic acids (C. 1910, 
 I- 25) : 
 
 I. C 6 H 5 C(OH)(COCH 8 )C0 2 CH 8 +H,0 = C 6 H 6 CHO+CH,COOH + CH 3 OH + CO. 
 II. C 6 H 6 C(OH)(COCH S )C0 2 CH 8 +0 + H,0 = C 6 H S CO.COOH+CH 3 COOH + CH 3 OH. 
 
 Properties. Benzaldehyde and its homologues are mostly liquid 
 bodies, which possess an aromatic odour, and reduce ammoniacal 
 silver solutions with the production of a metallic mirror, (i) They 
 are readily oxidised to carboxylic acid. (2) They differ from the fatty 
 aldehydes in that they are, as a general rule, readily oxidised to 
 alcohols and acids by alcoholic or aqueous alkalies ; it appears that 
 this reaction is, however, only peculiar to those aldehydes in which 
 the CHO group is in direct union with the benzene nucleus. (3) Nascent 
 hydrogen reduces them to alcohols when they are in part, through the 
 union of two aldehyde residues, converted into hydro-benzo'ins. (4) 
 They combine with acid alkaline sulphites. (5) With hydroxylamine 
 they yield aldoximes, which manifest rather remarkable isomeric 
 relations. (6) They form phenyl-hydrazones with phenyl-hydrazin. 
 (7) With primary amines : aldehyde imines (Schiff's bases). (8) With 
 the salts of nitro-hydroxylaminic acid NaON : NOONa and benzol- 
 sulphydroxamic acid they form hydroxamic acids (C. 1904, I. 1204). 
 (9) Phosphorus pentachloride replaces their aldehyde oxygen by two 
 atoms of chlorine. (10) Chlorine substitutes aldehyde hydrogen. 
 
 They do not polymerise, as do the first members of the group of 
 fatty aldehydes. 
 
 Nuclear Syntheses. (i) In the reduction of aromatic aldehydes 
 e.g. in the electrolytic reduction (B. 29, R. 229 ; C. 1907, I. 339) there 
 occurs, along with alcohol formation, a production of hydro-benzoin 
 analogous to the pinacone formation : 
 
 2C 6 H 5 CHO+2H = C 6 H 5 CH(OH) CH(OH).C 6 H 6 hydro-benzoin. 
 
 (2) A very interesting reaction of the aldehydes is their conversion 
 into benzoins, through the agency of alcoholic potassium cyanide. 
 Two aldehyde molecules combine to a polymeric body : 
 
 2C 6 H 5 CHO = C 6 H 5 CH(OH).CO.C 6 H 5 benzoin. 
 
 See B. 29, 1729 ; 31, 2699, for the condensations of benzylidene- 
 aniline and benzaldehyde by potassium cyanide. 
 
 (3) The aromatic aldehydes combine with the most heterogeneous 
 bodies e.g. aldehydes, ketones, monocarboxylic acids, dicarboxylic 
 acids, etc. water always disappearing. 
 
 These so-called condensation reactions proceed similarly to the aldol- 
 condensation, only there is generally an elimination of water, as in the 
 
BENZALDEHYDE 
 
 255 
 
 conversion of aldol into croton-aldehyde. The condensation agents are 
 HC1 gas, zinc chloride, sulphuric acid, glacial acetic acid, acetic anhy- 
 dride, dilute sodium hydroxide, baryta water, a solution of potassium 
 acetate, and potassium cyanide (primary, secondary, and tertiary bases). 
 In this manner benzaldehyde can undergo the following rearrange- 
 ments without difficulty : 
 
 CH,COOH 
 
 C 8 H 5 CHO 
 
 CH,CHO 
 
 CH.COCH, 
 
 CH,(COOH) 2 
 
 CH,COCH,CO,C,H 5 
 
 C 6 H 5 CH=CH.COOH Cinnamic acid 
 C 6 H 5 CH=CH.CHO Cinnamic aldehyde 
 
 C 6 H 5 CH=CH.CO.CH 3 Benzal-acetone 
 
 C 8 H 6 CH=C(COOH) 2 Benzal-malonic acid 
 
 p jj jj_Q/CO 2 C 2 H 5 Benzal-aceto-acetic 
 
 \COCH 3 ester. 
 
 Pyrones CO[C(CH 3 ) : C(C 6 H 5 )] 2 O (B. 29, 1352) result when two 
 molecules of benzaldehyde condense with ketones like diethyl-ketone. 
 Pyridin derivatives result when benzaldehyde and aceto-acetic ester 
 condense with ammonia and aniline ; whereas benzylidene-diaceto- 
 acetic esters are formed under the influence of aliphatic amines (B. 29, 
 R. 841). 
 
 The benzaldehydes also condense with phenols and anilines, forming 
 derivatives of triphenyl-methane. 
 
 Benzaldehyde, bitter-almond oil, benzyl hydride C 6 H 5 .CHO, b.p. 179, 
 with specific gravity 1-050 (15), is a colourless liquid with high refrac- 
 tive power. Formerly it was prepared exclusively from its glucoside 
 amygdalin (see below) . At present it is only the officinal bitter-almond 
 oil water, aqua amygdalarum amararum, in which hydrocyanic acid is 
 the active ingredient, that is made from the amygdalin. It has the 
 characteristic agreeable " bitter-almond oil " odour. It is soluble in 
 thirty parts water, and is miscible with alcohol and ether. Benzalde- 
 hyde does not occur already formed in the bitter almonds, but is 
 produced, as demonstrated by Wohler and Liebig in 1831, from 
 the glucoside amygdalin contained in the oil. This is easily converted, 
 by boiling with dilute acids or upon standing in contact with the 
 unorganised ferment emulsin, also present in bitter almonds, into benz- 
 aldehyde, glucose, and hydrocyanic acid. 
 
 Amygdalin : C 20 H 27 NO 11 -f2H 2 O=C 6 H 5 CHO+2C 6 H 12 O 6 -fCNH. 
 
 In the general methods common to the formation of all aldehydes, 
 reactions were indicated which would lead to the production of benz- 
 aldehyde. Thus it is formed (i) from benzyl alcohol ; (2) from calcium 
 benzoate and formate ; (3) from benzal chloride ; (4) from benzyl 
 chloride, from which it is prepared technically by oxidation with lead 
 nitrate ; (5) from toluol and chromyl chloride CrO 2 Cl 2 ; (6) from 
 benzene and CO with HC1, Cu 2 Cl 2 , and Al 2 Br 6 ; and (7) from phenyl- 
 magnesium bromide and formic ester or its derivatives. 
 
 In describing the transformations of the aldehydes, benzaldehyde 
 was chosen as the example. It even absorbs oxygen from the air and 
 becomes benzoic acid, and when mixed with acetic anhydride and sand 
 it not only yields benzoic acid but also benzoyl-hydrogen peroxide 
 
256 ORGANIC CHEMISTRY 
 
 (C 6 H 5 COO) 2 (B. 27, 1959). Sodium amalgam reduces it to benzyl 
 alcohol and hydro-benzoin, while PC1 5 changes it to benzal chloride. 
 It shows both oxime and phenyl-hydrazone formation, etc. 
 
 With sulphurous acid it combines to an oxy-sulphonic acid soluble 
 in water, from which the aldehyde can be recovered by simple heating. 
 This process can be utilised for regenerating benzaldehyde (C. 1904, 
 
 1. 1145). 
 
 Homologous Benzaldehydes. o- } m-, and p- Toluic aldehydes boil at 
 200, 199, and 204. The o- and m-bodies smell like benzaldehyde, 
 while the p-compound has an odour like that of pepper. 
 
 a-Toluic aldehyde, phenyl-aeetaldehyde C 6 H.C 5 H 2 .CHO, boiling at 
 206, and isomeric with the three toluic aldehydes, is produced (i) by 
 distillation of a-toluate of calcium and calcium formate ; (2) when 
 chromyl chloride and water act upon ethyl-benzene ; (3) by acting 
 with water on j8-bromo-styrolene ; (4) by heating phenyl-lactic acid or 
 phenyl-glycidic acid with dilute sulphuric acid ; (5) from phenyl-a- 
 chloro-lactic acid C ii H 5 .CH(OH).CHCl.CO 2 H, by the action of alkalies 
 (B. 16, 1286 ; A. 219, 179) ; and (6) from phenyl-glycerie acid or its 
 j8-lactone C 6 H 6 CH(O)CH(OH)CO, by heating alone or in water (C. 
 1900, I. 887). Phenyl-acetaldehyde has a sweetish odour resembling 
 that of hyacinths, and is used in perfumery. It polymerises easily on 
 keeping. On heating with alcoholic potash it forms a mixture of 
 triphenyl - benzol and 1, 3-diphenyl-tetramethylene (B. 38, 1965). 
 a-Phenyl-propyl-aldehyde, hydro-atropa-aldehyde C 6 H 5 (CH 3 )CH.CHO, 
 b.p. 204, is obtained from unsym. phenyl-methyl-glycol by heating with 
 dilute H 2 SO 4 (B. 39, 2297), from phenyl-methyl-glycidic acid or unsym. 
 phenyl-methyl-ethylene oxide on heating alone (B. 38, 704 ; C. 1905, 
 II. 1628). a-Phenyl-butyraldehyde (C 6 H 5 )CH.CHO, b.p. 211, from 
 unsym. phenyl-ethyl-glycol (B. 39, 2300). a-Propyl- and a-iso-butyl- 
 phenyl-acetaldehyde, b.p. 28 122, b.p. 30 153, a-Methyl-phenyl-propyl- 
 aldehyde, b.p. 19 130, from the corresponding glycidic acids by method 
 12 (C. 1905, I. 347). 
 
 Phenyl-propyl-aldehyde, hydro-cinnamic aldehyde C 6 H 6 CH 2 CH 2 CHO, 
 b.p. 13 105 (B. 31, 1992), is best obtained by reduction of cinnamic 
 aldehyde acetal. 3, 5-Dimethyl-benzaldehyde, mesityl-aldehyde (CH 3 ) 2 
 C 6 H 3 CHO, b.p. 221, from mesitylene bromide (/. pr. Ch. 2, 58, 359). 
 
 2, 5-Dimethyl-benzaldehyde, b.p. 10 100, is obtained from p-xylol-gly- 
 oxylic acid by method 13 ; while from p-xylol, CO, and HC1, etc., by 
 method 9, 2, 4-dimethyl-benzaldehyde is formed, with migration of 
 atoms (C. 1903, I. 830). 
 
 Cumic aldehyde, cuminol, p-iso-propyl-benzaldehyde (CH 3 ) 2 CH 
 [4]C 6 H 4 [i]CHO, boiling at 235, with specific gravity 0-973 (13), 
 occurs, together with cymene, in Roman carraway oil, and in oil of 
 Cicuta virosa, or water-hemlock (B. 26, R. 684). Cuminol possesses an 
 aromatic odour. Dilute nitric acid oxidises it to cumic acid ; chromic 
 acid converts it into terephthalic acid. Cumic acid (q.v.) and cumyl 
 alcohol are produced when it is digested with alcoholic potash. When 
 distilled with zinc dust, cymol results. 
 
 DERIVATIVES OF BENZALDEHYDE. 
 
 Haloid Derivatives. The halogen compounds corresponding to 
 benzaldehyde are obtained by the action of PC1 5 or PBr 6 upon it. 
 
DERIVATIVES OF BENZALDEHYDE 257 
 
 Benzol chloride, benzylidene chloride, chloro-benzene, chloride of 
 bitter-almond oil, C 6 H 5 CHC1 2 , boiling at 213, with specific gravity 1-295 
 (16), results from the action of chlorine upon boiling toluene, from 
 toluene (A. 139, 318 ; 146, 322) and PC1 5 at I7O-200, as well as from 
 benzaldehyde and COC1 2 (Z. /. Ch. 2, 7, 79). It changes to benzal- 
 dehyde when it is heated to I4o-i6o with water, or to 6o-70 with 
 anhydrous oxalic acid. Benzal bromide boils at I3O-I4O (20 mm.). 
 Acetals of the aromatic aldehydes are obtained from these with dilute 
 alcoholic HC1, or with orthoformic ester, and from the aldehyde 
 chlorides with sodium alcoholates (B. 31, 1989 ; 40, 3903). 
 
 Benzal dimethyl and diethyl ether, boiling at 208 and 220, benzol 
 diacetyl ester, melting at 44 and boiling at 220 (A. 102, 368 ; 146, 323), 
 are produced when sodium methylate, sodium ethylate, and silver 
 acetate act upon benzal chloride. The diethyl ether is also formed 
 from benzaldehyde and orthoformic ester (B. 29, 247), as well as from 
 benzylidene-imide hydrochloride with alcohol. 
 
 Sulphur Derivatives of Benzaldehyde. Compare the thio-acetalde- 
 hydes : a- and fi-trithio-benzaldehyde melt at 167 and 225 (B. 29, 159). 
 Polymeric thio-benzaldehyde melts at 83 (B. 24, 1428). When heated 
 with finely divided copper they yield stilbene C 6 H 5 .CH=CH.C 6 H 5 . 
 
 On mercaptals and sulphones from benzaldehydes, see B. 35, 2343. 
 
 Benzaldehyde-potassium bisulphite, potassium-oxy-benzyl sulphonate 
 C 6 H 5 CH(OH)SO 3 K+ JH 2 O, see A. 85, 186. 
 
 Sodium-benzaldehyde sulphoxylate C 6 H 5 CH(OH)O.SONa ; on addi- 
 tion of benzaldehyde to a feebly alkaline sodium hydrosulphite solu- 
 tion, it is precipitated in flakes. The secondary salt is more stable than 
 the primary (B. 42, 4634). 
 
 Nitrogenated Benzaldehyde Derivatives. Phenyl-dinitro-methane 
 C 6 H 5 CH(NO 2 ) 2 , m.p. 79, is formed by the action of N 2 O 4 upon benzal- 
 doxime or acetyl-benzoyl oxime C 6 H 5 C(NOH).COCH 3 ; on heating to 
 130 it forms benzaldehyde, and by reduction with Al amalgam benzyl- 
 amine and NH 3 (/. pr. Ch. 2, 65, 197 ; 73, 494 ; C. 1901, II. 1007 ; 
 1906, II. 1003). On the action of diazo-benzol chloride upon phenyl- 
 dinitro-methane, see C. 1909, II. 905. 
 
 When ammonia acts at 20 upon a concentrated alcoholic solution 
 of benzaldehyde, the first product is the very unstable benzaldehyde 
 ammonia (C 6 H 5 CHOH) 2 NH, m.p. 45, which quickly breaks up into 
 benzaldehyde, water, and hydrobenzamide, tribenzal-diamine (C 6 H 5 
 CH) 3 N 2 , melting at 110. When this body is heated it is transposed 
 to amarine or triphenyl - dihydro - glyoxaline (q.v.). When hydro- 
 chloric acid gas is conducted into the alcoholic benzene solution of 
 hydro-benzamide, benzylidene imide C 6 H 5 CH : NH.HC1, melting with 
 decomposition at 180, separates. Water immediately resolves this 
 body into benzaldehyde and ammonium chloride (B. 29, 2144 ; 42, 2216). 
 
 Benzal-ethyl-amine C 6 H 5 .CH : N.C 2 H 5 , b.p. 195. Benzal-aniline, 
 benzylidene-aniline C 6 H 5 .CH : N.C 6 H 5 , m.p. 45, from benzaldehyde 
 and aniline, with elimination of water. In the presence of concen- 
 trated HC1 the aromatic aldehydes combine with anilines to chloro- 
 hydrates of the aldehyde-anilines, like C 6 H 5 CH(OH)NHC 6 H 5 .HC1, 
 which sometimes, especially in the oxy-benzaldehydes, represent fairly 
 stable compounds ; the free hydrates, on the other hand, usually lose 
 H 2 O readily, and pass into the benzylidene compounds (SchifFs bases. 
 VOL. II. S 
 
258 ORGANIC CHEMISTRY 
 
 B. 35, 984). In a few cases Schiff's bases, like the benzaldoximes, 
 occur in two isomeric forms (B. 43, 3359). On the nitrogenation and 
 sulphuration of benzylidene-anilines, see C. 1903, I. 231. With 
 benzaldehyde in alcoholic KCN solution benzaniline does not give the 
 benzoin reaction, but a complex condensation takes place with the help 
 of hydrocyanic acid (see B. 38, 1761). On the condensation of benz- 
 aniline with malonic ester, aceto-acetic ester, and similar bodies, see 
 B. 31, 2596 ; 32, 332 ; 36, 937. 
 
 Benzylidene-p-amido-dimethyl-aniline C 6 H 5 CH : NC 6 H 4 N (CH 3 ) 2 , 
 m.p. 99, yellow needles, forms, with one molecule HC1 a red, and with 
 two molecules HC1 a white, chlorohydrate (C. 1908, I. 1539). 
 
 When the o-phenylene-diamines and benzaldehyde interact, the 
 bodies resulting at first are : benzylidene-o-phenylene-diamine NH 2 . 
 C 6 H 4 N : CH.C 6 H 5 , m.p. 61, and dibenzylidene-o-phenylene-diamine 
 C 6 H 4 [N : CH.C 6 H 5 ] 2 . However, they readily rearrange themselves 
 into isomeric, ring-shaped imidazole derivatives, or aldehydes (B. 29, 
 1497). The amidated benzylidene-anilines and bis-benzylidene-p- 
 phenylene-diamines, like NH 2 C 6 H 4 .CH : N.C 6 H 4 N : CHC 6 H 4 NH 2 have 
 dyeing properties similar to those of the amido-azo-bodies ; the azo- 
 methine group CH : N is a " chromophore," like the azo-group 
 N=N , but to a much smaller extent (B. 31, 2250). In both cases 
 the introduction of " auxo-chromic " groups (NH 2 , OH, etc.) produces 
 a deepening of the colour (C. 1907, I. 106). 
 
 Benzylidene-hydrazin, benzal-hydrazin C 6 H 5 CH : NNH 2 , m.p. 16, 
 b.p. 14 140, is formed from hydrazin hydrate with benzaldehyde and 
 barium oxide, and from benzalazin by boiling with hydrazin hydrate. 
 It easily passes into benzalazin in various ways ; with acetic anhydride 
 it gives benzal-acetyl-hydrazin C 6 H 5 CH : N.NHCOCH 3 , m.p. 134, 
 which is also formed from acetyl-hydrazin and benzaldehyde (B. 35, 
 
 Benzalazin C 6 H 5 CH : N.N : CHC 6 H 5 , m.p. 93, from benzaldehyde 
 and hydrazin, decomposed by heat into nitrogen and stilbene. By 
 reduction with zinc dust and glacial acetic acid it splits off NH 3 and 
 yields dibenzyl-amine. By sodium amalgam it is first converted into 
 benzyl-benzyhdene-hydrazin and further into sym. dibenzyl-hydrazin. 
 With bromine it unites to form a tetrabromide, which readily decom- 
 poses with evolution of nitrogen (cp. /. pr. Ch. 2, 58, 372). "With di- 
 methyl sulphate the benzalazin combines to form an ammonium com- 
 pound C 6 H 5 CH:N(CH 3 )(OS0 3 CH 3 )N :CHC 6 H 5 which, with water, 
 breaks up into benzaldehyde and methyl-hydrazin (A. 376, 244). On 
 the influence of magnesium organic compounds upon benzalazin, see 
 B. 43, 740. 
 
 Benzal-phenyl-hydrazone C 6 H 5 CH : NNHC 6 H 5 , m.p. 152 (A. 190, 
 134), is converted by acetic anhydride and H 2 SO 4 into a stereo-isomeric 
 body of m.p. 136 ; sodium amalgam reduces it to sym. benzyl-phenyl- 
 hydrazin. On oxidation, the benzal-phenyl-hydrazones yield dibenzal- 
 diphenyl-hydro-tetrazone, benzile-osazone, dehydro-benzal-phenyl-hydra- 
 
 zone and tetraphenyl-tetrazolin c 6 2 5 K T= N~?r 6 H 5 ^' ^ 5 2 3)- 
 
 Numerous benzal compounds of hydrazin derivatives have been 
 
 prepared ; they serve to characterise the latter. 
 
 Benzaldoximes. The interaction of hydroxylamine and benzalde- 
 
BENZALDOXIMES 259 
 
 hyde produces a-benzaldoxime, benzantialdoxime, m.p. 35 and b.p. 
 117 (14 mm.). Hydrochloric acid, sulphuric acid, or bromine changes 
 it, with the simultaneous production of unstable salts (B. 27, R. 599), 
 into /3-benzaldoxime, iso-benzaldoxime, benzo-synaldoxime, m.p. 
 125. For another method, see A. 365, 202. When this body is dis- 
 tilled under reduced pressure, it passes into the a-derivative. Each of 
 these isomerides gives rise to two structurally isomeric series of alkyl 
 ethers, in one of which the alkyl is joined to oxygen, in the other to 
 nitrogen, as the first, upon decomposition, yield a-, and the second 
 j8-alkyl-hydroxylamines. Hantzsch and Werner attribute the iso- 
 merism of the a- and /2-aldoximes to the spatial arrangement of the 
 hydroxyl group with reference to nitrogen. The oximes are distin- 
 guished as benzanti- and benzo-synaldoxime (B. 24, 3481). The sym. 
 configuration would fall to the /J-aldoxime, because in a series of re- 
 actions e.g. treatment of the acid ester with alkalies it changes more 
 readily and completely to benzo-nitrile than the a-body : 
 
 P TT PTT O TT CTT 
 
 (a-) Benzantialdoxime UT (/M Benzo-synaldoxime ' 
 
 The following formulae would then correspond to the N- and O- 
 alkyl ethers of these compounds : 
 
 X 6 H 5 CH f > C 6 H 5 CHO ^ C 6 H 6 CH 
 
 Anti- 
 alkyl 
 
 fC 6 H 5 CH > C 6 H 5 CHO , C 
 
 I CH 3 N ^ > CH 3 ONH 2 < * 
 
 N OCH Syn - 
 
 ether. |C 6 H 5 CH. f _> C 6 H 5 CHO 4-, C 6 H 5 CH> 
 
 -. ^6 n 5 ^*\ 
 
 1 I >< 
 
 CH 3 N / ' > CH 3 NH(OH) <> N^l( 
 
 byn 
 alky 
 ether. 
 
 The benzaldoximes and phenyl cyanate combine to isomeric 
 phenyl-urethane derivatives C 6 H 5 CH : NOCONHC 6 H 5 . The N-alkyl 
 ethers also unite with phenyl cyanate, forming azoxazol (iuTO-ab'- 
 diazol) derivatives (B. 27, 1957) : 
 
 C 6 H 5 CH\ c g H 6 NCQ C 6 H 5 CH.N(C 6 H 5 )\ CQ 
 C 7 H 7 ^_/ ( > C 7 H 7 * - O/ 
 
 Benzaldoxime is also produced from benzyl-amine by oxidation 
 with Caro's acid, and is further oxidised by that agent to phenyl-nitro- 
 methane and benzo-hydroxamic acid (B. 34, 2023, 2262). 
 
 Anti-benzaldoxime-o-methyl ether is an oil, b.p. 191. It results 
 from the interaction of a-benzaldoxime with sodium alcoholate and 
 methyl iodide or with diazo-methane (C. 1909, 1. 1754). Hydrochloric 
 acid resolves it into benzaldehyde and a-methyl-hydroxylamine. N- 
 Methyl ether melts at 45-49. Its hydrobromide is formed on heat- 
 ing a-benzaldoxime, methyl, bromide, and methyl alcohol in a sealed 
 tube to 85. On exposure it rearranges itself into the syn-form (B. 29, 
 R. 866 ; A. 365, 215). Syn-benzaldoxime-N-methyl ether, melting at 
 82, is formed, together with the isomeric o-ether, from syn-benzal- 
 doxime, methyl iodide, and sodium ethylate (B. 24, 2812), or by the 
 action of the chloride of j8-methyl-hydroxylamine upon benzaldehyde 
 (A. 365, 205). By the action of PC1 5 in etheric solution it is transposed 
 into the isomeric monomethyl-benzamide : 
 
 C 6 H 5 CH.O.NCH 3 - > C 6 H 5 CO.NHCH 3 . 
 
260 ORGANIC CHEMISTRY 
 
 Benzaldoxime-0-benzyl ether C 6 H 5 CH : NOCH 2 C 6 H 5 is also known 
 in a liquid and a solid modification, m.p. 31. p-Chloro-benzaldoxime- 
 p-chloro-benzylj.ether, m.p. 114, and p-bromo-benzaldoxime-p-bromo- 
 benzyl ether, m.p. 130, see B. 33, 1975. These substances can only 
 be split up with difficulty into aldehydes and hydroxylamines. 
 
 Benzaldoxime-N-benzyl ether C 6 H/H.O.NCH 2 C 6 H 5 , m.p. 82, is 
 obtained from sodium iso-benzaldoxime with benzyl chloride, and 
 from j8-dibenzyl-hydroxylamine by oxidation. Benzaldoxime-N- 
 benzyl ethers with nuclear substitution are transposed in a peculiar 
 manner by sodium ethylate (A. 298, 187) : 
 
 XCeH/H.O.NCHjjCgHg > XC 6 H 4 CH 2 N.O.CHC 6 H 5 . 
 
 / 
 N-Phenyl-benzaldoxime C C H 6 CH^ | , melting at 109, results 
 
 pJOgHg 
 
 from the union of benzaldehyde with ^-phenyl-hydroxylamine (p. 78) 
 (B. 27, 1958 ; C. 1898, II. 80). 
 
 Benzantialdoxime acetate C 6 H 6 CHNO(OC.CH 3 ) melts at 15 
 (B. 27, R. 599). 
 
 .Benzaldoxime peroxide C 6 H 6 CH : N.O.ON : CHC 6 H 5 , m.p. 105 
 with decomposition, results from the oxidation of benzaldoxime with 
 sodium hypochlorite, or amyl nitrite, and also, together with benzo- 
 nitrolic acid, from the action of nitrous acid upon phenyl-iso-nitro- 
 methane. On heating with chloroform it undergoes a peculiar trans- 
 formation into dibenzenyl-azoximeC 6 H 6 C^~^ c H * (B. 39, 2522). 
 
 Benzaldoxime-N-carbonamide C 6 H 5 CH.O.N.CONH 2 , m.p. 125, 
 from benzaldehyde and hydroxyl-urea (Vol. I.). On heating it breaks 
 up into a-benzaldoxime, benzo-nitrile, and cyanic acid (C. 1908, 1. 948). 
 
 Benzaldoxime-0-aeetic acid C 6 H 5 CHN(OCH 2 COOH) melts at 98, 
 
 /N.CH 2 .COOH 
 
 the N -derivative CeHgCH^ | at 183 with decomposition. 
 
 They are formed when chloracetic acid acts upon potassium benzal- 
 doxime. When decomposed, the first yields gly collie acid and the second 
 amidoxyl-acetic acid HO.NH.CH 2 .COOH (I. 350) (B. 29, R. 169). 
 Isomerisms similar to those of the benzaldoximes are shown by many 
 substituted benzaldoximes, ketoximes, the benzile-dioximes, etc. 
 
 Benzal-amido-sulphonie acid C 6 H 6 .CH : NSO 3 H results from benz- 
 aldehyde and amido-sulphonic acid (B. 25, 472). 
 
 Substituted benzaldehydes behave towards oxidising and condensing 
 agents like benzaldehyde itself. The formation of heterocyclic bodies 
 from o-nitro- and o -amido-benzaldehyde is especially worthy of notice. 
 
 Haloid benzaldehydes are formed when oxalic acid or sulphuric 
 acid (A. 272, 148) acts upon the halogen benzal chlorides ; or by oxidis- 
 ing cinnamic acids containing halogens in the nucleus : 
 
 o-Chloro-benzaldehyde melts at -4 ; boils at 213 ; the oxime melts at 75 
 
 m-Chloro-benzaldehyde 17; 213; ,, 70 
 
 p-Chloro-benzaldehyde ,, 47 ; ,, 213 ; ,, ,, 106 
 
 o-Bro mo- benzaldehyde .. 21 ; o-Io do- benzaldehyde ,, 37 
 
 p-Bromo-benzaldehyde ,, 57 ; p-Iodo-benzaldehyde ,, 73. 
 
 See B. 29, 875, for the di- and tetrachloro-benzaldehydes. 
 
NITRO-BENZALDEHYDES 261 
 
 o-, m-, p-Iodoso-benzaldehydes C 6 H 4 (IO)CHO, and o- m-, p- 
 iodo-benzaldehydes C 6 H 4 (IO 2 )(CHO), have been obtained from the cor- 
 responding iodide-chlorides (B. 29, R. 774). 
 
 Nitro-benzaldehydes NO 2 C 6 H 4 CHO. On dissolving benzaldehyde 
 in nitro-sulphuric acid, the chief product is meta-nitro-benzaldehyde. 
 o-Nitro-benzaldehyde is formed simultaneously (B. 14, 2803). o-Nitro- 
 benzaldehyde is obtained by the oxidation of o-nitro-benzyl alcohol 
 (C. 1899, II. 950) or from o-nitro-cinnamic acid or its ester (B. 17, 121). 
 It results also from o-nitro-toluol by oxidation with manganese per- 
 oxide and sulphuric acid (C. 1907, I. 383) or manganese persulphate 
 (SO 4 ) 2 Mn (C. 1906, II. 1590). Also, with its oxime, from the di-mercury 
 compound of o-nitro-toluol by oxidation with HNO 2 (C. 1908, II. 209). 
 
 Para-nitro-benzaldehyde results (i) by the oxidation of p-nitro- 
 cinnamic acid (B. 14, 2577) ; (2) by allowing CrO 2 Cl 2 and water to act 
 upon p-nitro-toluol in carbon disulphide (B. 19, 1061) ; (3) when 
 p-nitro-benzyl chloride is boiled with water and lead nitrate, or when 
 sulphuric acid acts upon p-nitro-benzal chloride. 
 
 The oximes of o- and p-nitro-benzaldehyde are obtained from o- 
 and p-nitro-toluol by the action of amyl nitrite and sodium ethylate 
 (C. 1899, II. 371 ; 1900, I. 886, 1273). In the form of their acetates 
 C 6 H 4 (NO 2 )CH(OCOCH 3 ) 2 they are obtained from o- and p-nitro-benz- 
 aldehyde by the oxidation of a solution of o- and p-nitro-toluol in acetic 
 anhydride sulphuric acid with chromic acid (A. 311, 355) : 
 
 M.p. M.p. M.p. 
 
 o-Nitro-benzaldehyde, 46; oxime, 103 (a), 149 (0) ; hydrazone, 153* 
 
 m-Nitro-benzaldehyde, 58; 117 ( a ), 118 (0) ; 121 
 
 p-Nitro-benzaldehyde, 107; 130 (a), 174 (0) ; 155. 
 
 o- and p-Nitro-a- or anti-benzaldoximes pass, on illumination of 
 their benzene solution, into the more stable 6- or syn-aldoximes (B. 36, 
 4268). 
 
 On the behaviour of the nitro-benzaldehydes in the animal organ- 
 ism, see B. 25, 2457. 
 
 The effect of light on o-nitro-benzaldehyde in indifferent solvents 
 is to transpose it entirely into o-nitroso-benzbie acid (q.v.). In alcoholic 
 solution the corresponding o-nitroso-benzoic esters are produced, with 
 the acetals of o-nitroso-benzaldehyde as intermediate products. The 
 entry of a second substituent in o-position to the aldehyde group, con- 
 nects the acetal formation and the power of transposition (" Steric Hin- 
 drance," A. 371, 319). o-Nitro-benzaldehyde condenses with aldehyde 
 and acetone, through the action of dilute caustic soda, to o-nitro-phenyl- 
 lactic acid aldehyde and o-nitro-phenyl-lactic methyl ketone, which 
 caustic soda converts into indigo : 
 
 CH,.CHO fCH(OH).CH,.CHO_ 
 
 c , [i]CHO ' I NO, i CO . CO c H 
 
 -- 
 
 5-Nitro-2-chloro-benzaldehyde NO 2 .C 6 H 3 C1.CHO, melts at 80 ; its 
 oxime at 147. The latter is readily converted by boiling alkali into 
 nitre-salicylic acid (B. 26, 1253). 3-Nitro-4-bromo-benzaldehyde NO 2 . 
 C 6 H 3 BrCHO melts at 103 ; its oxime at 145 (B. 24, 3775). 2-Nitro- 
 5-chloro- and -bromo-benzaldehyde, m.p. 76 and 74 respectively, by 
 
262 ORGANIC CHEMISTRY 
 
 nitrogenation of m-chloro- and m-bromo-benzaldehyde respectively 
 (B. 38, 2811). 2-Nitro-4-chloro- and -bromo-benzaldehyde, m.p. 67 
 and 98 respectively, are formed by a peculiar reaction from 4-amido- 
 2-nitro-benzaldoxime on treatment with ferric sulphate and concen- 
 trated HC1, and HBr respectively (B. 37, 1861). 
 
 2, 4-Dinitro-benzaldehyde (NO 2 ) 2 [2, 4]C 6 H 3 CHO, m.p. 72, is ob- 
 tained by the oxidation of 2, 4-dinitro-benzyl-aniline or its sulphonic 
 acid (NO 2 ) 2 C 6 H 3 CH 2 NHC 6 H 4 SO 3 H with permanganate or chromic acid, 
 the Schiff bases first formed being split up by the acid ; it is also pro- 
 duced by the breaking up of its dimethyl-amido-anile (NO 2 ) 2 C 6 H 3 CH : 
 NC 6 H 4 N (CH 3 ) 2, obtained by the action of p-nitroso-dimethyl-aniline 
 upon 2, 4-dinitro-toluol. From 2, 4, 6-trinitro-toluol we obtain in 
 this manner the 2, 4, 6-trinitro-benzaldehyde (NO 2 ) 3 [2, 4, 6]C 6 H 2 CHO, 
 m.p. 119. Like the o-nitro-benzaldehyde, the o, p-dinitro- and the 
 sym. trinitro-benzaldehyde are easily transposed by light into p-nitro- 
 o-nitroso- and dinitro-o-nitroso-benzoic acid (B. 35, 2704 ; 36, 959 ; 
 C. 1902, II. 741). 
 
 Hydroxylamino-, Nitroso-, Azoxy-, and Azo-benzaldehydes. By 
 electrolytic reduction in sulphuric acid, and by reduction with zinc dust, 
 we obtain from m- and p-nitro-benzaldehyde in the first place aldehydo- 
 phenyl-hydroxylamines CHO.C 6 H 4 NHOH, which, with unchanged 
 nitro-aldehyde, combine to form aldehydo-phenyl-nitro-n-benzal- 
 doximes NO 2 C 6 H 4 CH<^ C8H * CHa The o-nitro-benzaldehyde may be 
 
 reduced to the very unstable hydroxylamino-benzaldehyde, which is 
 easily condensed to its inner anhydride anthranile. In the form of its 
 nitroso-compound CHO.C 6 H 4 N(NO)OH, m.p. 52-5, we obtain o-hydro- 
 xylamino-benzaldehyde by reducing o-nitro-benzaldehyde with zinc 
 dust in the presence of amyl nitrite (B. 42, 2574). The same nitroso- 
 compound also results from anthranile with HNO 2 . With alkalies it 
 gives stable salts, while with acids it is converted into a mixture of 
 diazotised o-amido-benzaldehyde and o-nitroso-benzaldehyde CHO 
 [i]C 6 H 4 [2]NO, white needles of m.p. 110 (B. 42, 2573). 
 
 o- Hydroxylamino - benzaldoxime HONH[ 2 ]C 6 H 4 CH : NOH, m.p. 
 120, is formed by reduction of o-nitro-benzaldoxime. This oxime is 
 also formed from anthranile with hydroxylamine, and is reconverted 
 into anthranile by acids. By oxidation, in air, it passes into the oxime 
 of 2-azoxy-benzaldehyde ON 2 (C 6 H 4 [2]CHO) 2 , m.p. 211 (B. 36, 3654). 
 The aldehyde melts at 119 ; it is more easily obtained by the reduction 
 of o-nitro-benzaldehyde acetic acid splitting (B. 39, 4265). On a 
 peculiar reduction product of o-nitro-benzaldehyde C 14 H 12 N 2 O 5 , m.p. 99, 
 which reacts like a molecular combination of o-nitro- and o-hydroxyl- 
 amino-benzaldehyde, see B. 39, 4252. By a further reduction of 
 m- and p-nitro-benzaldoxime-n-aldehydo-phenol ether, we obtain 
 the corresponding derivatives of azoxy-benzaldoximes, which are split 
 up by ferric chloride into the azoxy-benzaldehydes ON 2 (C 6 H 4 CHO) 2 , 
 m m.p. 129, p- m.p. 190, and nitroso-benzaldehydes NO.CgH 4 .CHO. 
 p-Azoxy-benzaldehyde is also obtained in the form of its aniline com- 
 pound ON 2 (C 6 H 4 CH :NC 6 H 5 ) 2 from p-nitro-benzyl-aniline NO 2 C 6 H 4 
 CH 2 NHC 6 H 5 by the action of potash (see also B. 36, 3469). p-Nitroso- 
 benzaldehyde combines with aniline to form the anile of p-benzol-azo- 
 benzaldehyde C 6 H 5 N : NC 6 H 4 CHO, m.p. 120, whose acetal is also pro- 
 
AMIDO-BENZALDEHYDES 263 
 
 duced by the reduction of a mixture of nitro-benzol and p-nitro-benz- 
 aldehyde alcohol, beside the acetal of p-azo-benzaldehyde CHO.C 6 H 4 N : 
 NC 6 H 4 CHO, m.p. 238 (B. 35, 2434 ; 36, 793 ; C. 1902, II. 195, 700 ; 
 1903, I. 286). o- and m-azo-benzaldehyde-aeetal, m.p. 144 and 150, 
 are formed by reduction of the nitro-benzaldehyde acetals with zinc 
 dust and sodium hydrate (C. 1904, I. 1498). The o-azo-benzaldehyde- 
 acetal yields on saponification with dilute SO 4 H 2 y-oxy-B-phenyl- 
 
 c^otn 
 indazol C.H 4 <^ >NCiHj| (C. 1907, I. 1575). 
 
 Amido-benzaldehydes NH 2 C 6 H 4 CHO. The o- and p-bodies are 
 obtained in the action of ferric chloride upon their oximes, which are 
 formed by the reduction of o- and p-nitro-benzaldoximes with 
 ammonium sulphide (B. 15, 2004 ; 16, 1998). 
 
 o-Amido-benzaldehyde is also obtained by reducing o-nitro-benz- 
 aldehyde and anthranile (see this) with ferrous sulphate and ammonia 
 (B. 17, 456). m-Amido-benzaldehyde is formed when m-nitro- 
 benzaldehyde is reduced with tin and glacial acetic acid. 
 
 A further process for preparing o- and p-amidated benzaldehydes 
 uses the action of sulphur alkalies upon nitro-benzyl alcohols and their 
 derivatives ; a reduction of the nitro-group and an oxidation of the 
 alcohol group takes place (C. 1900, I. 1084). 
 
 o-Amido-benzaldehyde . . melts at 39 : its oxime at 135 (B. 36, 803) 
 m-Amido-benzaldehyde is yellow and amorphous ; 88 
 
 p-Amido-benzaldehyde . . melts at 70 : 124 (/. pr. Ch. 2, 56, 97). 
 
 For preparing the derivatives of the amido-benzaldehydes, very 
 unstable in themselves, their acetyl derivatives are specially suitable. 
 Their melting-points are : o-, 71 ; m-, 84 ; and p-, 161 (C. 1903, I. 
 
 775, 9 21 )- 
 
 p-Dimethyl- and p-diethyl-amido-benzaldehydes, melting at 73 and 
 81, are obtained when the condensation products from chloral and 
 dialkyl-aniline e.g. p-dimethyl-amido-phenyl-trichlorethyl alcohol 
 (CH 3 ) 2 NC 6 H 4 CH(OH)CC1 3 are acted upon "with alcoholic potash 
 (B. 19, 365). p-Dimethyl-amido-benzaldehyde condenses to hexa- 
 methyl-leucaniline (see Triphenyl-methane dyes) with dimethyl- 
 aniline. 
 
 For further condensation products of p- dimethyl- amido-benz- 
 aldehyde, see B. 35, 3569. 
 
 Tetramethyl-2, 4-diamido-benzaldehyde, m.p. 8, b.p. 14 203, from 
 tetramethyl-m-phenylene-diamine and chloral (B. 41, 91). 
 
 The o-amido-benzaldehyde is easily diazotated with concentrated 
 HC1 ; on treating the diazonium salt with sodium nitride we obtain 
 
 o-azido-benzaldehyde ^>N|>]C 6 H 4 CHO, m.p. 37. This body is also 
 produced by a peculiar transposition of the diazo^benzaldoxime an- 
 hydride, indiazonoxime, N : N[2]C 6 H 4 C : NOH, m.p. 166, formed during 
 the diazotation of o-amido-benzal-dioxime, performed by warming in 
 water, or treating with cold alkali. The same reactions have been 
 carried out with dimethyl-, dichloro-, and dibromo-o-amido-benz- 
 aldehyde. 
 
 o-Azido-benzaldehyde, on heating alone, or with water, loses 
 nitrogen, and passes into anthranile. A similar behaviour is shown 
 
264 ORGANIC CHEMISTRY 
 
 by the o-aziflo-benzaldoxime N 3 [2]C 6 H 4 CH : NOH, m.p. 103, which, 
 on boiling with NaHO, gives n-oxy-indazol (B. 35, 1885) : 
 
 n-Oxy-indazol Anthranile (?). 
 
 The Hetero-ring Formations of o-Amido-benzaldehyde. o-Amido- 
 benzaldehyde combines especially readily with compounds containing 
 a CH 2 -CO group, in the presence of dilute caustic soda. The products 
 resulting at first are of an aldol nature, for they immediately split off 
 water and yield quinolin or its derivatives. o-Amido-benzaldehyde 
 combines with acetaldehyde to quinolin, with acetone to quinaldin, 
 with malonic acid to fi-carbostyrile-carboxylic acid (B. 25, 1752), and 
 with urea to quinazolone (B. 28, 1037). Alcoholic ammonia transposes 
 the acidyl-o-amido-benzaldehydes into quinazolins : 
 
 ru rwn f CH = CH 
 
 CH " CHO > C 6 H J Quinolin 
 
 CH CH 
 
 < CH '>' CQ ->C 6 H 4 4 Quinaldin 
 
 lN-=C-CH 3 
 
 l[ 2 ]NH 
 
 Vsn^vs^A/s ^ /" IT J I f 
 
 lie acid 
 
 CH.(CO,H), r JCH-C COOH _carbostyrile-carboxy- 
 
 -NH,,-H,0 
 
 (CH=N 
 C 4 H 4 J Quinazolone 
 
 NH CO 
 
 rv-\rtir\ NH fCH^N Pheno-5-methyl-meta- 
 
 iMT/^n r w - ^+ C * H * I I diazin -Methyl-quin- 
 
 [ 2 ]NH.CO.CH 3 (N=C.CH 3 azolin. 
 
 On the condensation of o-amido-benzaldehyde by means of zinc 
 chloride to anhydro-o-amido-benzaldehyde (C 7 H 6 N)a., see B. 31, 658. 
 
 Benzaldehyde-m-sulphonic acid SO 3 H.C 6 H 4 CHO, white deliquescent 
 crystals (B. 24, 791). Benzaldehyde-o-sulphonic acid is obtained from 
 o-chloro-benzaldehyde with sodium sulphite, as well as by oxidation of 
 o 2 -stilbene-disulphonic acid. The chloride, m.p. 114, treated with 
 NH 3 and then oxidised in air, yields saccharin (C. 1898, I. 540 ; 1901, 
 I. 806). Benzaldehyde-mono- and -disulphonic acids are also produced 
 by oxidation of toluol-sulphonic acids with MnO 2 and fuming sulphuric 
 acid (C. 1904, II. 1269). 
 
 (3) AROMATIC MONOKETONES. 
 
 The oxidation products of the secondary phenyl-paraffin alcohols 
 are mixed ketones, in which an aromatic and an aliphatic hydrocarbon 
 residue are joined by the CO group. The ketones containing two 
 benzene residues linked by carbonyl, such as benzo-phenone or diphenyl- 
 ketone, will be discussed later in connection with the corresponding 
 hydrocarbons, like diphenyl-methane. 
 
 Formation. Mixed aromatic-aliphatic ketones are usually produced 
 by reactions similar to those employed with the aliphatic ketones : 
 
 (i) By the oxidation of secondary alcohols, like phenyl-methyl 
 carbinol. 
 
 (20) From the di-secondary and secondary-tertiary phenyl-ethylen e 
 
AROMATIC MONOKETONES 265 
 
 glycols and ethylene oxides by heating with dilute acids or alone 
 (C 1905, II. 1628 ; 1907, I. 1577) : 
 
 C 6 H 5 CH(OH).CH(OH)CH 3 > C a H 5 CH 2 .CO.CH 3 < C 6 H 6 iH.O.CH.CH 3 . 
 
 (zb) From the iodo-hydrins of some olenn-benzols on treating with 
 NO 3 Ag or HgO, with migration of the phenyl group : 
 
 C H6 \C(OH).CHI.CH 3 > CH 3 .CO.CH/ C H6 
 
 (3) When sulphuric acid acts upon phenyl-acetylene : 
 C 6 H 5 C:CH --- >C 6 H 5 COCH 3 . 
 
 Nuclear Synthesis. (4) By the distillation of a mixture of calcium 
 salts of an aromatic and a fatty acid (C. 1910, I. 1008). 
 
 (5) By the action of zinc alkyls on acid chlorides (A. 118, 20). 
 
 (6) By the action of alkyl-magnesium iodides upon aromatic 
 nitriles addition products are obtained, which, on decomposition with 
 mineral acids, give aromatic ketones (C. 1902, I. 299) : 
 
 C 6 H 6 C=N+CH,MgI -- > C H * C -- " c H * COCH s- 
 
 Benzo-nitrile oxide CjHg.C with alkyl-magnesium haloids gives 
 
 ketoximes (B. 40, 1672). 
 
 (7) From benzols by the action of aliphatic acid chlorides and Al 
 chloride or ferric chloride. Additive compounds of these chlorides 
 and the acid chlorides are first formed, e.g. (CH 3 COC1)A1C1 3 , and these 
 thereupon react with the hydrocarbons (B. 33, 815 ; C. 1900, II. 188 ; 
 1901, I. 1263). 
 
 (8) By heating aryl-glycidic acids. These are easily obtained 
 synthetically by condensing aromatic aldehydes or ketones with 
 a-chloro-propionic ester and sodium ethylate (C. 1906, I. 669) : 
 
 C 6 H 5 COCH 3 - * C 6 H 5 (CH 3 )do.(!;COOH - * C,H 6 (CH 3 )CHCO.CH 3 . 
 
 (9) From aldehydes with diazo-methane (B. 40, 479). 
 
 (10) In the alkyl-phenyl ketones the H atoms adjoining the car- 
 boxyl group may be replaced by alkyls by the action of sodium amide 
 and halogen alkyls (C. 1909, I. 647 ; II. 600) : 
 
 C 6 H 5 COCH 2 CH, --+ C 6 H 6 CO.C(C 2 H 5 ) 2 CH 3 . 
 
 (n) By decomposing j3-ketone-car boxy lie acids e.g. mono- and 
 dialkyl-benzoyl-acetic acids (B. 16, 2131) with alcoholic potash. 
 
 (12) Acidulated benzols finally result, as a consequence of intra- 
 molecular rearrangement, upon heating the alkyl ethers of phenyl- 
 olefin alcohols, which are prepared by the distillation of ortho-ethers 
 of aceto-phenone. In this way the acidyl benzols can be built up from 
 aceto-phenone (Claisen, B. 29, 2931) : 
 
 C 8 H 5 CO.CH 3 ->C,H 5 C(OCH 3 ) 2 .CH 3 -^C 6 H 5 C(OCH 3 ) : CH 2 ~>C e H 6 COCH,.CH 3 
 
 Aceto-phenone and higher ketones are found in the so-called heavy 
 benzene oil of coal-tar (B. 36, 754). 
 
 Properties and Behaviour. The mixed aromatic-aliphatic ketones 
 are colourless liquids, insoluble in water, and possess an odour which 
 is not disagreeable. 
 
266 ORGANIC CHEMISTRY 
 
 (i) On reduction they pass into secondary alcohols or the corre- 
 sponding alkyl-benzols (C. 1905, I. 29). 
 
 (20) Chromic acid transforms the ketone C 6 H 5 .COR into benzoic 
 acid and the alkyl, which is further oxidised. 
 
 (26) Potassium permanganate converts them into a-ketone-carbo- 
 xylic acids (B. 23, R. 640 ; 24, 3543 ; 26, R. 191). 
 
 (3) Acids and acid amides, with the same number of carbon atoms, 
 strangely enough, are formed when phenyl-alkyl ketones are heated 
 with yellow ammonium sulphide (/. pr. Ch. 2, 81, 74, 382) : 
 
 C 6 H 5 COCH 2 CH 3 - \ /~r>ATTj 
 
 1 - > C 6 ii 5 Crl 2 Crl 2 CxUJN.rl 2 
 
 With increasing number of carbon atoms in the side chain, the 
 yield of carboxylic acids decreases, so that it vanishes in phenyl-heptyl 
 ketone. 
 
 (4) On heating benzene ketones with sulphuric acid, the acetyl 
 group splits off, -and benzol-sulphonic acid results (B. 19, 2623). 
 
 (5) Those ketones in which the CO group is attached to the benzene 
 nucleus do not unite with alkaline bisulphites. 
 
 (6) The phenyl-alkyl ketones apparently form but one acetoxime 
 with hydroxylamine ; the opposite is true of benzaldehyde. 
 
 (7) They form hydrazones with phenyl-hydrazin. 
 
 (8) With phosphoric and arsenic acids the aryl-methyl ketones 
 especially form crystalline compounds, some of which, when heated, 
 regenerate the hydrocarbons with elimination of the keto-group 
 (B. 32, 1549 i 35, 2313). 
 
 (9) On heating with sodium amide in benzene solution, the trialkyl- 
 aceto-phenones break up into benzene and the amides of the corre- 
 sponding trialkyl-acetic acids (C. 1909, I. 912 ; II. 600) : 
 
 C 6 H 5 CO.C(CH 3 ) 3 -> C 6 H 6 +NH 2 CO.C(CH 3 ) 3 . 
 
 Aceto-phenone, phenyl-methyl ketone, acetyl-benzol C 6 H5.CO.CH 3 , 
 m.p. 20, b.p. 202, crystallises in large plates. It is applied as an 
 opiate under the name of hypnone. It is formed (i) from phenyl- 
 methyl carbinol ; (2) from phenyl-acetylene ; (3) by distilling benzoate 
 of calcium with calcium acetate ; (4) by the action of zinc methyl 
 upon benzoyl chloride ; (5) from benzene, acetyl chloride, and A1C1 3 ; 
 (6) from benzaldehyde and diazo-methane ; (7) from benzoyl-aceto- 
 acetic ester C 6 H 5 CO.CH(COCH 3 ).COOC 2 H 5 and benzoyl-acetic ester. 
 The methods 3 and 5 are employed in its preparation. 
 
 Nascent hydrogen converts it readily into phenyl-methyl carbinol. 
 Chromic acid oxidises it to benzoic acid, and potassium permanganate 
 to phenyl-glyoxylic acid. 
 
 Aceto-phenone, like acetone, has been introduced into numerous 
 nuclear-synthetic reactions. Some of the simplest of these will be 
 given. It may be condensed to dypnone (q.v.) and to [i, 3, $\-triphenyl- 
 benzol (cp. C. 1900, II. 255), two bodies bearing the same relation to 
 aceto-phenone that mesityl oxide and mesitylene have to acetone. 
 
 Aceto-phenone also condenses in the most varied proportions with 
 benzaldehyde, forming benzal-aceto-phenone, benzal-diaceto-phenone, 
 and dibenzal-triaceto-phenone (B. 29, 1488). It yields the nitrile of 
 a-phenyl-lactic acid with hydrocyanic acid. At higher temperatures 
 
ACETO-PHENONE 
 
 267 
 
 chlorine enters the methyl group ; PC1 6 substitutes the ketone-oxygen- 
 producing aeeto-phenone chloride (A. 217, 105). Amyl nitrite and 
 sodium ethylate convert aceto-phenone into iso-nitroso-aceto-phenone, 
 which will be described under Phenyl-glyoxal. 
 
 With ammonia, aceto-phenone reacts like the higher aliphatic 
 ketones, with formation of aceto-phenone ammonia (C 6 H 5 (CH 3 )C) 3 N 2 , 
 m.p. 115 (C. 1907, I. 809). 
 
 Ortho-ethers of aceto-phenone, like aceto-phenone ortho-ethyl ether 
 C 6 H 5 C(OC 2 H 5 ) 2 CH 3 , b.p. 107 (17 mm.), are prepared from aceto- 
 phenone and ortho-formic ethers (B. 40, 3908). When heated under 
 ordinary pressure, or by the action of acid chlorides and pyridin (B. 31, 
 1019), they lose alcohol and pass into alkyl ethers of phenyl-olefin 
 alcohols. They yield aniles with aniline. Aceto - phenone - anile 
 C 6 H 6 C : (NC 6 H 5 )CH 3 , m.p. 41, b.p. 310. 
 
 Aceto-phenone-ethyl mercaptol C 6 H 5 C(SC 2 H 5 ) 2 CH 3 is oxidised by 
 permanganate, in the cold, to the disulphone CgH 6 C(SO 2 C 2 H 5 ) 2 CH 3 , 
 m.p. 120 (B. 35, 2343). 
 
 Aceto-phenone oxime C 6 H 5 .C : (N.OH).CH 3 , m.p. 59. It is only 
 known in one modification (B. 24, 3482). By the action of concen- 
 trated sulphuric acid, or of HC1 in glacial acetic acid, it is converted 
 into acetanilide C 6 H 5 .NH.CO.CH 3 . This remarkable intramolecular 
 atomic rearrangement was discovered by Beckmann (" Beckmann's 
 Transposition/' B. 20, 2580 ; 23, 2746). 
 
 Other ketoximes behave in an analogous manner. The reaction 
 has been applied in determining the point of double union in the 
 higher olefin-monocar boxy lie acids, and for the decomposition, or 
 rupture, of ring ketones. 
 
 Aceto-phenone-phenyl-hydrazone melts at 105. 
 
 Aceto-phenone Homologues. These are numerous, and can be 
 arranged in two groups : (A) ketones whose CO group is attached to 
 the benzene ring acidulated benzols ; (B) ketones whose CO group is 
 not in immediate union with the benzene ring phenylated fatty ketones. 
 
 (A) Acidulated benzols have been made, especially by the general 
 methods 4, 6, 7, 10, n, 12. 
 
 Benzoylated paraffins : 
 
 Propio-phenone . 
 Butyro-phenone 
 Valero-phenone . 
 Iso-valero-phenone . 
 Tert. butyl-phenyl ketone . 
 Caprono-phenone 
 Iso-amyl-phenyl ketone 
 Diethyl-aceto-phenone 
 Ethyl-dimethyl-aceto-phenone 
 Hexyl-phenyl ketone . 
 Propyl-dimethyl-aceto-phenone 
 Triethyl-aceto-phenone 
 Lauroyl-benzol . 
 Palmityl-benzol . 
 
 C 6 H 5 COCH 2 CH 3 . 
 C 6 H 5 CO(CH 2 ) 2 CH 3 . 
 C 6 H 5 CO(CH<,) 3 CH 3 
 C 6 H 5 CO.CH 2 CH(CH 3 ) 2 
 C 6 H 5 CO.CH(CH 3 ) 3 
 C 6 H 5 CO(CH 2 ) 4 CH 3 . 
 C 6 H 5 COCH 2 .CH 2 CH(CH 3 ) 2 
 C 6 H 5 COCH(C 2 H 5 ) 2 . 
 C 6 H 5 COC(CH 3 ) 2 C 2 H 5 . 
 C 6 H 5 CO(CH 2 ) 5 CH 3 . 
 C 6 H 5 COC(CH 3 ) 2 C3H 7 . 
 C 6 H 5 COC(C 2 H 5 ) 3 
 C 6 H 5 CO(CH 2 ) 10 CH 3 . 
 C 6 H.CO(CH 2 ) 14 CH 3 . 
 
 b.p. 
 
 210 ! 
 
 M 
 
 222 
 
 ,, 
 
 237 
 
 ,, 
 
 2 3 
 
 '' n 
 
 220 2 
 
 b.p-14 
 
 133 3 
 
 b.p. 
 
 240 
 
 b.p. 10 
 
 II2 4 
 
 b-p-io 
 m.p. 
 
 145 4 
 
 47 
 59 
 
 Literature. x B. 26, 1427 ; 35, 1073. 
 4 C. 1909, I. 647. 5 B. 28, R. 648. 
 
 2 A. 310, 318. 3 B. 40, 1601 
 
268 ORGANIC CHEMISTRY 
 
 /CH 
 Benzoyl-trimethylene C fl H 5 CO.CH<Q , formed on heating trimethy- 
 
 lene-benzoyl-acetic acid to 200, boils at 239. Its oxime melts 
 at 88. 
 
 Benzoyl-tetramethylene C 8 H 6 COCH<^ 2 ^>CH 2 , from the chloride of 
 
 tetramethylene-carboxylic acid, boils at 258 (B. 25, R. 372). 
 
 Nuclear- acidulated A Iky I -benzols, Homobenzoylated Paraffins. 
 p-Acetyl-toluol is produced when concentrated nitric acid acts upon 
 cymene (pp. 58), and acetyl-3, 4~(o)-xylol is formed from camphor by 
 the action of concentrated sulphuric acid (B. 26, R. 415) : 
 
 p-Acetyl-toluol CH 3 CO[4].C,,H 4 [i].CH3 boils at 224 
 l-Acetyl-3, 4-(o)-xylol .... 246 
 
 l-Acetyl-2, 4-(m)-xylol . . 
 
 Acetyl-p-xylol .... 
 
 Acetyl-mesitylol .... 
 l-Acetyl-2, 4, 5, 6-durol melts at 73 and 
 
 247 
 
 224 
 
 235 (B. 24, 3542) 
 
 206 (B. 29, 847). 
 
 (B) Phenylated fatty ketones have been prepared by methods 2, 4, 
 5, 6, 8, and n (p. 264 seq.) : 
 
 Benzyl-propyl ketone C ( ,H 5 CH 2 .CO.CH 2 CH 3 , b.p. 240, from benzyl 
 cyanide with propyl-magnesium iodide, etc. (C. 1902, I. 299). 
 
 Benzyl-methyl-ethyl ketone C 6 H 5 CH 2 CH 2 COCH 2 CH 3 , b.p. 257, 
 from a-benzylidene-methyl-ethyl ketone by reduction, or by distilla- 
 tion of calcium hydro-cinnamate or propionate (B. 35, 971). 
 
 Substituted Aceto - phenones. Haloid A ceto - phenones. Aceto- 
 phenones containing halogens in the methyl group will be discussed 
 after the corresponding ox3^gen derivatives : benzoyl-carbinol (q.v.), 
 phenyl-glyoxal (q.v.), and phenyl-glyoxylic acid (q.v.). p-Haloid 
 aceto-phenones, like C1.C 6 H 4 .CO.CH 3 , have been obtained from 
 haloid benzenes, acetyl chloride, and aluminium chloride (cp. haloid 
 thiophene ketones) (B. 24, 997, 3766) : 
 
 p-Chloraceto-phenone, acetyl-p-chloro-benzene, melts at 20 and 
 
 boils at 230 (B. 18, R. 502). 
 
 p-Bromaceto-phenone, acetyl-p-bromo-benzene, melts at 51. 
 p-Iodaceto-phenone, acetyl-p-iodo-benzene, melts at 83. 
 
 Nitro-aceto-phenones. The meta-body is the chief product (just as 
 in the case of benzaldehyde) when aceto-phenone is dissolved in fuming 
 nitric acid ; at 30-40 o-nitro-aceto-phenone predominates (B. 18, 
 2238). The three isomerides can be prepared from the three nitro- 
 benzoyl-aceto-acetic esters (see these) (A. 221, 323). 
 
 p-Nitro-aceto-phenone is formed when concentrated sulphuric acid 
 acts upon p-nitro-phenyl-propiolic acid (see this), through the rearrange- 
 ment of the nitro-phenyl-acetylene, formed at first, by water (A. 212, 
 160) (see method of formation 3). 
 
 o-Nitro-aceto-phenone, b.p. 16 159; oxime, m.p. 115 (C. 1902, I. 472) 
 m-Nitro-aceto-phenone, m.p. 81 ; ,, 131 (B. 37, 3542) 
 p-Nitro-aceto-phenone, ,, 80. 
 
 o-Nitro-aceto-phenone oxime is also produced from o-nitro-ethyl- 
 benzol NO 2 C 6 H4CH 2 CH 3 with amyl nitrite and sodium ethylate (see 
 Nitro-benzaldoximes, and C. 1900, II. 458). 
 
ACETO-PHENONE 269 
 
 m-Dinitro-aeeto-phenone, m.p. 83, is prepared from dinitro- 
 benzoyl-aceto-acetic ester with H 2 SO 4 (/. pr. Ch. 2, 65, 290). 
 
 o-Nitro-aceto-phenone, on gentle reduction with zinc dust and 
 sal ammoniac or tin and acetic acid, is converted into o-hydroxylamino- 
 
 aceto-phenone anhydride or o-methyl anthranile 
 
 iu, a colourless oil, easily volatilised with steam, which must be 
 regarded as analogous to anthranile ; like the latter, it forms with 
 sublimate a double compound, which, on further reduction, passes 
 into amido-aceto-phenone. On heating at ordinary pressure it is trans- 
 posed into indoxyl or converted into indigo (see Indigo syntheses, and 
 B. 36, 1611). 
 
 m-Hydroxylamino-, azoxy- and azo-aceto-phenones, see B. 36, 
 1618 ; C. 1903, II. 112. 
 
 Amido-aeeto-phenonesC 6 H 4 (NH 2 ).CO.CH 3 . 
 
 o-, m- and p-Amido-aceto-phenone are obtained : by reducing 
 o-nitro-aceto-phenone (A. 221, 326) ; the o-amido-aceto-phenone has 
 also been prepared from o-amido-phenyl-propiolic acid by boiling in 
 water (B. 15, 2153) ; from o-amido-phenyl-acetylene C 6 H 4 (NH 2 )C ; CH 
 by the action of sulphuric acid (B. 17, 964) ; by boiling o-amido-phenyl- 
 propiolic acid with water (B. 15, 2153) ; and a slight quantity on heating 
 aniline with acetic anhydride (B. 18, 2688). o- Amido-aceto-phenone is 
 a thick yellow oil, which boils at 242-252, and possesses a character- 
 istic sweetish odour, m- Amido-aceto-phenone melts at 93. p-Amido- 
 aceto-phenone melts at 106 ; its oxime melts at 147 (B. 20, 512). A 
 pine splinter dipped into the aqueous solution of o-amido-aceto-phenone 
 hydrochloride is coloured an intense orange-red. 
 
 o-, m- and p-Acetyl-amido-aceto-phenones CH 3 CONHC 6 H 4 COCH 3 , 
 m.p. 77, 129, and 167. The p-body is also formed from diacet- 
 anilide by transposition on heating with HC1 or zinc chloride (C. 1903, 
 
 i. 832). 
 
 Hetero-ring Formations of the Aromatic o-Amido-ketones. (i) Di- 
 
 methyl-quinolin is produced (B. 19, 1037) when o-amido-aceto-phenone 
 is digested with acetone and sodium hydroxide. 
 
 (2) o-Acetyl-amido-aceto-phenone is condensed by NaHO to 
 a-methyl-y-oxy- and a-oxy-y-methyl-quinolin (B. 32, 3228). 
 
 (3) and (4) Oily nitro-compounds are formed in the nitration of 
 phenyl-acetone and benzyl-acetone. They yield, by reduction, 
 j8-methyl-dihydro-ketol and tetrahydro-quinaldin (B. 14, 889), as the 
 o-amido-bodies (probably the o-amido-alcohols) produced at first 
 sustain an intramolecular anhydride formation : 
 
 c H ( WCO.CH.CH, NaOH ^ ^ f C(CH,)=CH ^^ 
 
 4 \[2]NH 2 CO.CH, HN C.CH 3 < ^ umoUn 
 
 C.H,,H,,O.CH, ^(C.H.{|; H -) C.H.(<y HCH ' <, 
 
 r H rvr TH ro rw ^ (c H /M CH "-- CH '- cacH A _ JCH 2 CH 2 Tetrahydro- 
 
 (_ 6 H s .t/rl 2 .Crl 2 .LU.L-rl 3 > ICH 4 < I > *-s"4 \ 
 
 \ \[ 2 ]NH 2 \NH-CHCH 3 ***&* 
 
 (4) AROMATIC MONOCARBOXYLIC ACIDS. 
 
 The aromatic carboxylic acids result upon replacing the hydrogen 
 in benzene or its homologues by the carboxyl group. This group in 
 
270 ORGANIC CHEMISTRY 
 
 these new derivatives is directly linked, as in the benzene-carboxylic 
 acids, to the benzene ring, or it replaces the hydrogen of an alkyl 
 side chain : 
 
 C 6 H 5 .C0 2 H 
 Benzole 
 acid 
 
 CH 3 .C 6 H 4 CO 2 H 
 Toluic acids 
 
 C 6 H 4 (C0 2 H) 2 
 Phthalic acids 
 
 (CH 3 ) 2 C 6 H 3 C0 2 H 
 Xylic acids 
 
 C 6 H 3 (C0 2 H) 3 . . 
 Benzene- tricar- 
 boxylic acids 
 
 C 6 H 5 CH 2 C0 2 H 
 Phenyl- acetic acid 
 a- Toluic acid 
 
 , C 6 (C0 2 H) 6 
 Mellitic acid 
 
 C 6 H 6 CH 2 CH 2 C0 2 H 
 Hydro-cinnamic acid 
 /S-Phenyl-propionic 
 acid. 
 
 Only the monocarboxylic acids will be now discussed, after the 
 monohydric aromatic alcohols. 
 
 General Methods of Formation. (i) While the aliphatic mono- 
 carboxylic acids or the paraffin carboxylic acids could not be obtained 
 by the oxidation of the paraffins, the aromatic acids can be readily 
 obtained from the benzene homologues by oxidising the side chains 
 to carboxyl groups. The importance of this reaction in establishing 
 constitution has been previously alluded to (p. 54). The most suitable 
 oxidants are chromic acid, dilute nitric acid, potassium permanganate, 
 and potassium ferricyanide. 
 
 (a) Oxidation with Chromic Acid. Only the para- and meta- 
 derivatives (the former more readily than the latter) of benzenes, carry- 
 ing two side chains, are oxidised to acids by chromic acid, while the 
 ortho- are either not attacked at all, or are completely destroyed. 
 
 In substituted alkyl-benzenes the alkyl group is prevented from 
 being oxidised by chromic acid, if a negative group occupying the o-posi- 
 tion with reference to the alkyl group is present (B. 15, 1021). The 
 oxidations are conducted either with free chromic acid in glacial acetic 
 acid, or with a mixture of potassium bichromate (3 parts) and sulphuric 
 acid (3 parts), diluted with 2-3 volumes of water. 
 
 (b) Oxidation with Nitric Acid. When oxidising with nitric acid, 
 use acid diluted with 3 parts of water and boil for some time, in 
 connection with a return condenser (2-3 days) . Konowaloff contends 
 that phenyl-nitro-paraffins are first produced ; these then are further 
 oxidised to carboxylic acids. To remove the nitro-acids which are 
 invariably formed, the crude product is digested with tin and concen- 
 trated hydrochloric acid ; this converts the nitro- into amido-acids, 
 which dissolve in hydrochloric acid. 
 
 In the derivatives with two different alky Is the higher alkyl is usually 
 attacked first, by nitric acid or chromic acid ; sometimes ketones are 
 present in the intermediate products (see Cymol, p. 58). 
 
 (c) Potassium permanganate often effects the oxidation at ordinary 
 temperatures. Ortho-di-derivatives may also be subjected to oxida- 
 tion, without the complete destruction . of the benzene nucleus follow- 
 ing as a consequence. 
 
 (d) Potassium ferricyanide oxidises methyl to carboxyl, if the nitro- 
 group occupies the ortho-position relatively to the methyl group. This 
 does not occur if the nitro-group holds the meta-position (B. 22, R. 501). 
 
 (2) Oxidation of the corresponding aromatic alcohols and alde- 
 hydes. 
 
 (3) By the addition of hydrogen to the unsaturated monocarboxylic 
 acids. Cinnamic acid becomes hydro-cinnamic acid. 
 
AROMATIC MONOCARBOXYLIC ACIDS 271 
 
 (4) By the reduction of phenylated oxy-fatty acids, haloid aro- 
 matic acids, and ketone-carboxylic acids. 
 
 (5) From the phenyl-alkyl ketones by heating with Am 2 S, acids and 
 acid amides of the same number of C atoms are produced : 
 
 1. C 6 H 5 .CH 3 - -^- C 6 H 5 COOH 
 
 2. C 6 H 6 .CH 2 OH - -+ C 6 H 5 CHO > C 6 H 5 COOH 
 
 3. C 6 H 5 .CH=CH.COOH - * C 6 H 5 CH 2 .CH 2 .COOH 
 
 4. C 6 H 6 .CH(OH).COOH - -> C 6 H 5 CH 2 .COOH 
 C 6 H 5 .CO.CO 2 H - 4HI -* C 6 H 5 CH 2 .COOH 
 C 6 H 5 .CHC1.COOH - --+ C 6 H 5 CH 2 COOH 
 
 5. C 6 H 5 .CO.CH 2 .CH 3 ^^ > C 6 H 5 CH 2 .CH 2 .COOH. 
 
 Nuclear-synthetic Reactions. (6a) Action of CO 2 upon aryl-mag- 
 nesium haloids ; phenyl-magnesium iodide gives rise to benzoic acid, 
 and benzyl-magnesium chloride to phenyl-acetic acid. 
 
 (6b) Action of sodium and CO 2 upon monobromo-benzols (Kekule"). 
 
 (7) A similar reaction is that of sodium and esters of chloro-carbonic 
 acid upon phenols and bromo-hydrocarbons (Wiirtz). 
 
 (8) Fusion of salts of the sulphonic acids with sodium formate. 
 
 (9) Action of carbon oxy-chloride upon benzols in the presence of 
 Al chloride, acid chlorides being obtained. 
 
 (10) Urea chlorides, in the presence of A1C1 3 , act in an analogous 
 manner upon the benzols. Acid amides are the first products. The 
 urea chlorides can be replaced (a) by cyanuric acid, or (b) by nascent 
 cyanic acid and HC1 (B. 32, 1116) ; (c) with phenyl cyanate we obtain 
 anilides ; (d) with phenyl-mustard oil we get thio-anilides ( /. pr. Ch. 
 2, 59, 572). 
 
 (n) By the action of benzene and aluminium chloride upon ali- 
 phatic lactones or olefin-carboxylic acids (C. 1908, II. noo). 
 (12) By the synthesis of the acid nitriles : 
 
 (a) Upon fusing the sulphonates with potassium cyanide ; 
 
 (b) By action of potassium cyanide upon the phenyl-alkyl chlorides ; 
 
 (c) When the bromo-nitro-benzols are heated with potassium 
 cyanide ; 
 
 (d) When diazo-salts are treated with potassium cyanide and 
 copper sulphate ; 
 
 (e) By heating the iso-nitriles alone. 
 
 The nitriles are changed to carboxylic acids when they are heated 
 with mineral acids, or alkalies. 
 Nuclear Syntheses : 
 
 6. C 6 H 5 MgI+CO 2 -- - C 6 H 5 COOMgI 
 
 7. C 6 H 5 Br+ClCO 2 C 2 H 5 +2Na - C 6 H 5 COOC 2 H 6 +NaCl+NaBr 
 
 8. C 6 H 5 SO 3 Na+HCOONa - ~> C 6 H 5 COONa-fHSO 3 Na 
 
 9. C 6 H 6 +COC1 2 - A1 ' cl6 > C 6 H 5 COC1+HC1 
 ioa. C 6 H 6 +C1.CONH 2 ^ L -> C 6 H 5 CONH 2 +HC1 
 
 b. C 6 H 6 +CO : NH 9 > C 6 H 5 CONH 2 
 
272 ORGANIC CHEMISTRY 
 
 loc. C 6 H 6 +CO : NC 6 H 5 - -^ > C 6 H 5 CONHC 6 H 6 
 
 d. C 6 H 6 +CS : NC 6 H 5 ^ > C 6 H 5 CSNHC 6 H 5 
 
 ii. C 6 H 6 +CH 3 CH : CH.COOH -^k+ C 6 H 5 (CH 3 )CH.CH 2 COOH 
 I2fl. C 6 H 5 S0 3 K+CNK - -> C 6 H 5 CN+S0 3 K 2 
 
 b. C 6 H 6 CH 2 C1+CNK- ~> C 6 H 5 CH 2 CN + KC1 
 
 c. C 6 H 4 BrNO 2 -fCNK- > C 6 H 4 (N0 2 )CN + KBr 
 
 d. C 6 H 5 N 2 C1+CNK - -* C 6 H 5 CN+N 2 +KC1 
 
 e. C 6 H 5 .NC - -> C 6 H 5 CN. 
 
 (13) By the oxidation of phenyl-pyro-racemic acids with hydrogen 
 peroxide (A. 370, 368) : 
 
 C 6 H 5 CHO * C 6 H 5 CH 2 .COCOOH > C 6 H 5 CH 2 COOH. 
 
 (14) Action of benzyl chloride upon sodium-aceto-acetic ester, and 
 the decomposition of the ketonic esters e.g. benzyl-aceto-acetic ester 
 by alkalies. * 
 
 (15) The decomposition of phenyl substitution products of the 
 malonic acid series e.g. benzyl-malonic acid by heat. 
 
 (16) Action of metallic sodium upon the acetates, propionates, etc., 
 of the phenyl carbinols : benzyl acetate yields phenyl-propionic benzyl 
 ester, while j3-benzyl-phenyl-butyric ester is obtained from benzyl pro- 
 pionate. This reaction recalls the synthesis of aceto-acetic ester 
 (Vol. I.), inasmuch as, in the latter, alcohol is split off under the in- 
 fluence of sodium, while, in the present reaction, acetic acid is liberated : 
 
 C 2 H 5 OOCCHo|Hj C 6 H 5 CH 2 OOC.CH 2 :H; 
 
 CH 3 CO lOGjHsi C 6 H 5 CH 2 iOOCCH 3 ; 
 
 Aceto-acetic ester /5-Phenyl-propionic benzyl ester. 
 
 Besides these, unsaturated acids are formed by secondary reactions, 
 leading, e.g., to phenyl-acrylic acid and phenyl-crotonic acid (A. 193, 
 321 ; 204, 200) : 
 
 COOCH 2 C 6 H 6 COONa 
 
 CH 2 CH 2 C 6 H 5 H - CH : CHC 6 H 5 + C H CH 3 + 
 
 Occurrence, Properties, and Behaviour. The aromatic acids occur 
 naturally, partly in a free state, partly in many resins and balsams, 
 and in the animal organism (see Benzoic acid). They arise also in the 
 decay of albuminoid bodies (see Hydro-cinnamic acid) (B. 16, 2313). 
 
 The aromatic acids are crystalline solids, which generally sublime 
 undecomposed. Most of them dissolve with difficulty in water ; hence 
 they are precipitated from their salt-solutions by mineral acids. Elec- 
 trolytic reduction (B. 39, 2933 ; 41,4148), or sodium amalgam, or zinc 
 dust will reduce some to aldehydes, while heating with concentrated 
 hydro-iodic acid, or phosphonium iodide, converts them into hydro- 
 carbons. When heated with lime, or soda-lime, their carboxyl groups 
 are eliminated and hydrocarbons result (cp. methane, Vol. I.). 
 
 From the polycarboxylic acids we obtain, as intermediate pro- 
 
BENZOIC ACID 273 
 
 ducts, acids having fewer carboxyl groups e.g. phthalic acid first 
 yields benzoic acid and then benzene. 
 
 The hydrogen of the benzene nucleus in the acids can sustain sub- 
 stitutions similar to those observed with the hydrocarbons and phenols 
 by the halogens, and the groups NO 2 , SO 3 H, NH 2 , OH, etc. In other 
 respects they are very similar to the fatty acids, and afford correspond- 
 ing derivatives by the alterations of the carboxyl group. 
 
 Benzoic acid, phenyl-formic acid C 6 H 5 .COOH, m.p. 120 and b.p. 
 250, occurs free in some resins, especially hi gum benzoin (from Styrax 
 benzoin), in dragon's blood (from Dcemonorops Draco], also in Peru 
 and tolu balsams, where it exists in the form of its benzyl ester. It is 
 found as hippuric acid in the urine of herbivorae. 
 
 It is produced by the general methods I and 2 from toluol (B. 36, 
 1798), benzyl alcohol, and benzaldehyde upon oxidation, as well as 
 from all hydrocarbons, alcohols, aldehydes, ketones, and carboxylic 
 acids, and their derivatives, which are obtainable from benzene by the 
 replacement of one hydrogen atom by a univalent side chain. Benzoic 
 acid can also be prepared by the oxidation of pure benzene ; this is 
 very probably due to the oxidation of diphenyl, which is formed at 
 first (A. 221, 234). Toluol can also be changed to benzyl chloride, and 
 this can then be oxidised (see "Preparation") to benzoic acid ; or benzo- 
 trichloride may be heated with water, concentrated sulphuric acid, or 
 anhydrous oxalic acid, and the product will be benzoic acid. It can 
 also be obtained, by the nuclear-synthetic reactions 6, 7, 8, 9, 10, and 
 12, from benzol, bromo-benzol, sodium-benzol sulphonate, and from 
 aniline through diazo-benzol chloride or phenyl-carbylamine. Finally, 
 CO 2 can be added to benzol by means of aluminium chloride, and 
 benzoic acid will result. 
 
 History. Benzoic acid was obtained from gum benzoin by sub- 
 limation, in the beginning of the seventeenth century. In 1775 Scheele 
 showed how the acid could be extracted from the gum with lime-water, 
 and then be precipitated from the solution of its calcium salt. In 1832 
 Liebig and Wohler, in the course of their classic research upon the 
 radicle benzoyl, determined the elementary composition of the acid 
 and illustrated its connection with benzaldehyde, as well as pointed out 
 the simplest transformation products of the acid. This investigation 
 produced such a profound impression upon the great master, Berzelius, 
 that he proposed as a substitute for the name benzoyl the name of the 
 new radicle containing more than two elements that of prom or 
 orthrin, from the Greek words, irpwi, the beginning of day, or opOpos, 
 morning dawn, because a new day was now breaking for organic chem- 
 istry. In 1834 Mitscherlich distilled benzoic acid with lime and got 
 benzene, which led him to regard the acid as a derivative of this hydro- 
 carbon. From that day, and especially since the establishment of the 
 benzene theory by Aug. Kekule, benzoic acid has been serving in con- 
 stantly increasing amount as the fundamental material for the pre- 
 paration of innumerable products. It is the carbon acid which has 
 been most exhaustively investigated. The study of its derivatives has 
 been greatly facilitated by the fact that the great crystallising power of 
 the acid has been transferred to most of its compounds (Vol. I.). 
 
 Preparation. Gum benzoin is sublimed or the resin is boiled with 
 milk of lime, and the benzoic acid precipitated with hydrochloric acid. 
 
 VOL. II. T 
 
274 ORGANIC CHEMISTRY 
 
 A more advantageous method is the production of the acid from hip- 
 puric acid. To accomplish this, boil the latter with concentrated hydro- 
 chloric acid. It is also produced when benzyl chloride is boiled with 
 dilute nitric acid (B. 10, 1275). Benzoic acid results from phthalic acid 
 by heating its calcium salt to 350 with calcium hydroxide. For its 
 preparation by hydrolysis of benzo-sulphonic acids, see C. 1899, 1. 1173. 
 
 Properties and Behaviour. Benzoic acid crystallises from hot water, 
 in which it is very soluble, in white, shining flakes. It sublimes 
 readily, and is carried over with steam. It dissolves with difficulty in 
 cold water (i part in 600 parts at o). Its vapours possess a peculiar 
 odour, which produces coughing and sneezing. The officinal benzoic 
 acid is obtained by the sublimation of Siam gum benzoin. 
 
 The acid yields benzene and carbon dioxide when heated with lime. 
 Benzoic acid, upon reduction, can yield tetra- and hexahydro-benzoic 
 acids (q.v.). 
 
 Salts. The benzoates are mostly quite readily soluble in water. 
 Ferric chloride throws out a reddish precipitate of ferric benzoate from 
 their neutral solutions. 
 
 The potassium salt 2C 7 H 5 KO 2 +H 2 O crystallises in concentrically 
 grouped needles. The calcium salt (C 7 H 6 O 2 ) 2 Ca-f 3H 2 O consists of 
 shining prisms or needles. The silver salt C 7 H 5 AgO 2 crystallises from 
 hot water in bright flakes. It dissolves in alcohol with great difficulty 
 (B. 35, 1094). 
 
 Homologues of Benzoic Acid. These compounds, like the homo- 
 logues of benzaldehyde and aceto-phenone, can be arranged in two 
 groups : alkyl-benzoic acids, in which the CO 2 H group is attached to the 
 benzene nucleus, as in benzoic acid itself, and phenyl-fatty acids, in 
 which the carboxyl group occurs in an aliphatic side chain of an alkyl- 
 benzene. The first group or class is naturally more nearly related to 
 benzoic acid than the second group. 
 
 Alkyl-benzoic acids. Toluic acids or methyl-benzoic acids CH 3 .C 6 H 4 . 
 CO 2 H are isomeric with a-toluic acid or phenyl-acetic acid. They are 
 produced when the three xylols are boiled for some time with dilute nitric 
 acid, and from bromo- and iodo-toluol by the nuclear-synthetic methods 
 6 and 7, as well as from the three toluidins according to method I2c. 
 
 o-Toluic acid can also be obtained by the reduction of phthalide 
 with hydriodic acid (B. 20, R. 378), as well as by rupturing the ring 
 of i, 3-naphthalene-disulphonic acid, i, 3-naphthalene derivatives, like 
 i, 3-dioxy-naphthalene, i, 3-naphthalene-disulphonic acid, i, 3-naph- 
 thol-sulphonic acid, upon fusing them with caustic alkali (B. 29, 1611). 
 p-Toluic acid is formed on boiling cymol with dilute nitric acid. 
 
 o-Toluic acid, m.p. 102 
 m-Toluic acid, ,, 110, b.p. 263 
 p-Toluic acid, 186, 275. 
 
 For derivatives of the toluic acids, see C. 1901, II. 289. 
 
 Ethyl-benzoic acids C 2 H 5 .C 6 H 4 .CO.OH. The three isomerides are 
 known. The o-acid results in the reduction of o-aceto-phenone-car- 
 boxylic acid, of methyl phthalide (B. 29, 2533), and of phthalic acetic 
 
 acid C r H 4 J\o with hydriodic acid (B. 10, 2206), and in 
 
 -Hj\o 
 ICO 
 
HOMOLOGUES OF BENZOIC ACID 275 
 
 that of the chloro-vinyl-benzoic acids with sodium amalgam (B. 27, 
 2761). o- m-, and p-Ethyl-benzoic acids melt at 68, 47, and 112 
 (B. 21, 2830 ; A. 216, 218) respectively. 
 
 Dimethyl-benzole acids (CH 3 ) 2 C 6 H 3 CO 2 H. Mesitylenic acid is 
 the most important member of this group. It is formed when mesity- 
 lene, symmetrical or [i, 3, 5]-trimethyl-benzol is oxidised with dilute 
 nitric acid. Iso-xylol or m-xylol is obtained when this acid is distilled 
 with lime. These reactions are the basis of the evidence that iso-xylol 
 and its oxidation products, m-toluic acid and iso-phthalic acid, are ni- 
 di-substitution products of benzene. Further oxidation of mesitylene 
 acid leads to uvitinic acid and trimesic acid. 
 
 i, 2 -Dimethyl-3 -benzole acid, a-hemellithic acid, m.p. 144 (B. 19, 2518) 
 
 i, 2-Dimethyl-4-benzoic acid, p-xylylic acid, . 163 (B. 17, 2374) 
 
 i, 3-Dimethyl-2-benzoic acid, . . . 98 (B. 11, 21) 
 
 i, 3-Dimethyl-4-benzoic acid, . . . . 126 (B. 12, 1968) 
 
 i, 3-Dimethyl-5-benzoic acid, mesitylenic acid, . ,, 166 (A. 141, 144) 
 
 i, 4-Dimethyl-2-benzoic acid, iso-xylylic acid, . ,, 132, b.p. 268 (A. 244, 54)- 
 
 Propyl-benzoic acids C 3 H 7 .C 6 H 4 CO 2 H. o- and p-n-Propyl and 
 p-iso-propyl-benzoic acids are known. p-Iso-propyl-benzoic acid, or 
 cumic acid, the oxidation product of the most note. Chromic acid 
 oxidises cumic acid to terephthalic acid, and potassium permanganate 
 converts it into p-oxy-iso-propyl-benzoic acid and p-acetyl-benzoic acid : 
 
 o, n-Propyl-benzoic acid . . m.p. 58 (B. 11, 1014) 
 p, n-Propyl-benzoic acid . . ,, 138 (B. 21, 2231) 
 o-Iso-propyl-benzoic acid . ,, 51 (A. 248, 63) 
 Cuminic acid, p-Iso-propylb. 117 (A. 219, 279 ; B. 20, 860). 
 
 Trimethyl-benzoie acids. Five are known. Durylic acid is ob- 
 tained from durol, and a-, )3-, and y-iso-durylic acids from iso-durol 
 (B. 27, 3446), upon oxidation with dilute nitric acid. j3-Iso-durylic 
 acid or mesitylene-carboxylic acid can also be formed from acetyl- 
 mesitylene (p. 268) (B. 25, 503). 
 
 i, 2, 3-Trimethyl-4-benzoic acid, Prehnitylic acid, melts at 167 
 i, 2, 3-Trimethyl-5-benzoic acid, a-Iso-durylic acid, ,, 215 
 i, 2, 4-Trimethyl-5-benzoic acid, Durylic acid, ,, 150 
 
 i, 2, 4-Trimethyl-6-benzoic acid, y-Iso-durylic acid, ,, 127 
 i, 3, 5-Mesitylene-carboxylic acid, /Mso-durylic acid, 152. 
 
 Tetramethyl-benzoic acids. Several are known : i, 2, 3, 4-tetra- 
 methyl-^-benzoic acid, melting at 165, is the oxidation product of 
 pentamethyl-benzene (B. 20, 3287) ; i, 2, 3, $-tetramethyl-6-benzoic 
 acid, durol-carboxylic acid (B. 29, 2569) ; 2, 3, 5, 6-tetramethyl~ 
 benzoic acid melts at 127 (B. 29, R. 233). 
 
 Pentamethyl-benzoic acid (CH 3 ) 5 .C 6 .CO 2 H, melting at 210, is made 
 according to method 9 (B. 22, 1221). 
 
 Phenyl-fatty acids. The most important representatives of this 
 group are phenyl-acetic acid or a-toluic acid, j8-phenyl-propionic acid 
 or hydro-cinnamic acid, and a-phenyl-propionic acid or hydratropic acid. 
 The synthesis and decomposition of the phenyl-f atty acids can be realised 
 in the same manner as the synthesis and decompositions of the fatty 
 acids (I. 251). The general methods of formation 2, 3, 4, 5, 6, n, 126, 
 
276 ORGANIC CHEMISTRY 
 
 13, 14, 15, and 1 6 are particularly prominent in the formation of the 
 phenyl-fatty acids. 
 
 Phenyl-acetie acid, alpha-toluic acid C 6 H 5 .CH 2 .CO 2 H, melts at 
 76 and boils at 262. This acid is formed from toluol just as acetic 
 acid is obtained from methane. Toluol is converted into benzyl chloride, 
 and this into benzyl cyanide, which is then digested with sulphuric acid 
 (B. 19, 1950 ; 20, 592) ; or the benzyl chloride is converted into benzyl- 
 magnesium chloride by magnesium in ether solution, and CO 2 is con- 
 ducted through (B. 35, 2523, 2694) : 
 
 r TT TTT v r H rn n/ * C H 5CH 2 CN > C 6 H 5 CH 2 CO 2 H 
 
 C 6 H 5 CH 3 - _^ C 6 H 5 CH a MgCl > C 6 H 5 CH 2 C0 2 H ' 
 
 It can also be obtained from phenyl-chloracetic acid C 6 H 5 .CHC1. 
 CO 2 H (B. 14, 240), from phenyl-gly collie acid or almond acid C 6 H 5 CH 
 (OH).CO 2 H, and phenyl-glyoxylic acid C 6 H 5 .CO.CO 2 H, by reduction. 
 
 It is produced when phenyl-malonic acid is heated (see method 15), 
 and it appears in the decay of albuminates (B. 12, 649). It may be 
 prepared, furthermore, from bromo-benzene, chloracetic ester, and 
 copper (B. 2, 738) ; by heating aceto-phenone with yellow ammonium 
 sulphide ; and by oxidising phenyl-pyro-racemic acid with H 2 O 2 . 
 Chromic acid oxidises it to benzoic acid. Chlorine, with heat, con- 
 verts it into phenyl-chloracetic acid, while in the cold the halogens 
 replace the aromatic hydrogen. 
 
 Tolyl-aeetic acids, alpha-xylic acids c.H 4 <^?* . The three 
 
 \L/rlj.L/O 2 ri 
 
 isomeric acids have been obtained from the three xylene bromides. 
 The ortho-acid melts at 89, the meta- at 61, and the para- at 91 (B. 20, 
 2051 ; 24, 3965)- 
 
 p-Xylyl-acetic acid (CH 3 ) 2 [i, 4]C 6 H 3 CH 2 COOH, m.p. 128, from 
 aceto-p-xylol and Am 2 S (C. 1897, II, 411). 
 
 Hydro-einnamie acid, jS-phenyl-propionic acid C 6 H 5 .CH 2 .CH 2 .CO 2 H, 
 m.p. 47 and b.p. 280, is isomeric with a-phenyl-propionic acid, the 
 three alpha-xylic acids, the three ethyl-benzoic acids, and the six 
 dimethyl-benzoic acids. It is obtained : from cinnamic acid C 6 H 5 CH : 
 CHCOOH by reduction, e.g. with electrolytic hydrogen evolved at a 
 Hg cathode (C. 1903, II. 107), or with sodium amalgam or HI (B. 30, 
 1680) ; from phenyl-ethyl-magnesium bromide C 6 H 5 CH 2 .CH 2 .MgBr 
 and CO 2 (C. 1904, I. 1493) ; from propio-phenone with yellow Am 2 S ; 
 from phenyl-ethyl cyanide (A. 156, 249) ; from benzyl-aceto-acetic 
 ester (B. 10, 758) and benzyl-malonic ester (A. 204, 176) ; also from 
 benzyl-acetic ester, with sodium (A. 193, 300) (see, further, methods 
 5, 6, 14, 15, and 16) ; and in the decay of albuminoid substances (B. 12, 
 649). Chromic acid oxidises it to benzoic acid. 
 
 The aliphatic haloid hydro-cinnamic acids, readily obtained by the 
 addition of haloid acids and halogens to cinnamic acid, will be described 
 after phenyl-lactic and phenyl-gly eerie acids. 
 
 Hydratropie acid, a-phenyl-propionic acid C 6 H 5 CH(CH 3 ).CO 2 H, 
 b.p. 265, is an oil, volatile in aqueous vapour. It results from the 
 reduction of atropic acid or a-phenyl-acrylic acid C 6 H 5 C(=CH 2 ).CO 2 H, 
 and in the action of hydriodic acid upon the prussic acid addition 
 product of aceto-phenone the nitrile of atro-lactinic acid (A. 250, 135). 
 
 Higher homologues of these acids are usually made according to 
 
HOMOLOGUES OF BENZOIC ACID 277 
 
 the following reactions : (i) By reduction of homologous cinnamic 
 acids (q.v.), which can be readily prepared by Perkins' reaction from 
 the aromatic aldehydes. (2) By the reduction of homologous almond 
 acids, obtained from homologous phenyl-glyoxylic acids. The latter 
 result upon oxidising homologous acetyl-benzols with potassium 
 permanganate. (3) From the alkyl-phenyl ketones with yellow Am 2 S. 
 (4) From alkylised benzyl cyanides, which are produced by the action 
 of alkylogens upon sodium-benzyl cyanide. (5) By the action of 
 benzene and aluminium chloride upon aliphatic lactones and olefm- 
 carboxvlic acids. 
 
 y-Phenyl-butyric acid C 6 H 5 .CH 2 .CH 2 .CH 2 .COOH, m.p. 517, is 
 formed by the reduction of phenyl-butyro-lactone or of phenyl-crotonic 
 acid (C. 1899, I. 792) from o>-bromo-propyl-benzol, Mg, and CO 2 (B. 43, 
 1233) ; also from phenyl-propyl ketone with Am 2 S (/. pr. Ch. 2, 
 80, 197). 
 
 j3-Phenyl-butyric acid C 6 H 5 (CH 3 )CH.CH 2 .COOH, m.p. 39, is formed 
 (i) by reduction of j8-methyl-cinnamic acid (B. 40, 1595) ; (2) from 
 crotonic acid, benzene, and A1 2 C1 6 (C. 1908, II. 1023) ; (3) from phenyl- 
 iso-propyl ketone with Am 2 S ; (4) by the disintegration of the addition 
 product of CH 3 MgI and benzal-malonic ester (C. 1905, II. 1023). 
 
 a-Phenyl-iso-butyric acid C 6 H 5 C(CH 3 ) 2 COOH, m.p. 78, b.p. 10 150- 
 155, from benzene, Al bromide, and a-bromiso-butyrie acid (C. 1899, 
 11.1047). 
 
 j8-Phenyl-iso-butyric acid, benzyl-methyl-acetic acid C 6 H5CH 2 
 CH(CH 3 )COOH, m.p. 37, b.p. 272, is split up by means of its quinine 
 salt into optically active components (C. 1902, I. 661). 
 
 S-Phenyl-valerianie acid C 6 H 5 (CH 2 ) 4 COOH, m.p. 59, by reduction 
 of phenyl-cumalin with HI (B. 29, 1675, R. 14). 
 
 a-Phenyl-iso-valerianie acid (CH 3 ) 2 CH.CH(C 6 H 5 )COOH, m.p. 59, 
 and a-methyl-jS-phenyl-butyric acid CH 3 CH(C 6 H 5 )CH(CH 3 )COOH, m.p. 
 132, from iso-propylidene-acetic acid and tiglinic acid with benzene 
 and A1 2 C1 6 (C. 1908, II. noo) . a-Methyl-y-phenyl-butyrie acid i C 6 H 5 CH 
 CH 2 CH(CH 2 )COOH, m.p. 67, from phenyl-iso-butyl ketone and 
 Am 2 S (/. pr. Ch. 2, 80, 198). 
 
 (b) DERIVATIVES OF THE AROMATIC MONOCARBOXYLIC ACIDS. 
 
 The derivatives of benzoic acid and its homologues arrange them- 
 selves into two groups. The first group comprises those compounds 
 resulting from the alteration of the carboxylic group (see Acetic acid, 
 Vol. I.), and the second group the aromatic substitution products with 
 the exception of the phenol monocarboxylic acids. The first group 
 divides itself into A, the benzoyl-compounds ; B, the benzenyl com- 
 pounds and the derivatives of ortho-benzoic acid. The chemistry of 
 no single carboxylic acid has been so fully developed as that of 
 benzoic acid. 
 
 BENZOYL COMPOUNDS. 
 
 i. ESTERS OF THE MONOBASIC AROMATIC ACIDS (Vol. I.). The 
 benzoic esters of the alcohols and phenols can be prepared like the acetic 
 esters. Like the latter, they are frequently employed in determining the 
 number of alcoholic hydroxyl groups present in a compound. They are 
 formed (i) by the action of hydrochloric acid upon an alcoholic solution 
 
278 ORGANIC CHEMISTRY 
 
 of benzole acid. In the substituted benzoic acids the following rule is 
 found : Ortho-substituted acids take a longer time to esterify than 
 m- and p-substituted acids (Z. physik. Ch. 24, 221). In the diortho- 
 substituted acids, like mesit3dene-carboxylic acid, 2, 6-dibromo-, 
 2, 4, 6-tribromo-, and 2, 4, 6-trinitro-benzoic acid, the ester formation 
 is usually so slow on boiling with alcohol and HC1 that it is practically 
 non-existent (B. 28, 1468 ; 29, 1399, 2301 ; 33, 2026 ; 42, 317 ; C. 1901, 
 II. 1117). But the ester formation is easily accomplished by heating 
 these acids to i8o-20O with alcohol, even without a catalyser 
 (Z. physik. Ch. 66, 275). The esters of these acids are also obtained 
 readily (2) from the silver salts with halogen alkyls, or the alkali salts 
 with dimethyl sulphate ; (3) by treating with diazo-methane (B. 31, 
 501). Furthermore, the esters of benzoic acid are produced (4) by the 
 action of benzoyl chloride or benzoic anhydride upon alcohols, alco- 
 holates, phenols, and phenolates. In carrying out the second reaction 
 it is advisable gradually to add sodium hydroxide, and shake the 
 alkaline, aqueous solution of the alcohols with benzoyl chloride until 
 there is a permanent alkaline reaction (Baumann, B. 19, 3218). In this 
 manner, also, the benzoyl ethers of the poly-alcohols, the polyoxy- 
 aldehydes e.g. of the glucoses have been obtained, and nearly all 
 have been completely benzoylated (B. 22, R. 668). 
 
 Methyl-benzole ester boils at 199. The ethyl ester boils at 213 ; the 
 n-propyl ester at 229; the n-butyl ester at 247. Glyeol dibenzoate 
 melts at 73 (B. 23, 2498). Glycerol tribenzoate melts at 76 (B. 24, 
 779 ; C. 1902, 1. 1224). Erythrol tetrabenzoate melts at 187. Mannitol 
 hexabenzoate melts at 124. Glucose pentabenzoate melts at 179. 
 
 Methylene dibenzoate CH 2 (OCOC 6 H 5 ), m.p. 96, by heating benzoyl 
 chloride with trioxy-methylene and zinc chloride, an intermediate pro- 
 duct being C1.CH 2 OCOC 6 H 5 (C. 1901, II. 396, 682). 
 
 Benzoyl-glyeollie acid C 6 H 5 CO.OCH 2 .CO 2 H consists of large prisms. 
 It results when nitrous acid acts upon hippuric acid. Phenyl-benzoic 
 ester melts at 71 and boils at 314 (A. 210, 255 ; B. 24, 3685). The 
 benzyl ester melts at 20 and boils at 323 (B. 20, 647). It occurs in 
 Peru balsam (A. 152, 130). For the benzoyl compounds of the homo- 
 logous phenols, see Phenols. 
 
 0-, m- and p-Toluie methyl esters, b.p. 213 and 221, m.p. 34 
 (C. 1901, II. 290). 
 
 Phenyl-acetic ethyl ester C 6 H 5 CH 2 COOC 2 H 5 , b.p. 226, from benzyl 
 cyanide, alcohol, and HC1 (A. 296, 361). Phenyl ester, m.p. 38, b.p. 15 
 1 80. Phenyl-acetic ester adds itself to aj3-unsaturated ketones and 
 acid esters (B. 42, 4496) With ethyl nitrate and potassium ethylate 
 it gives phenyl-nitro-acetic ester C 6 H 5 CH(NO 2 )COOR, which easily 
 eliminates the carbox-ethyl group and forms phenyl-nitro-methane. 
 With ethyl nitrite and K ethylate, iso-nitro-phenyl-acetic ester is 
 formed (B. 42, 1930). jS-Phenyl-propionic ethyl ester, b.p. 248. 
 
 2. AROMATIC ACID HALOIDS OR HALOID ANHYDRIDES OF THE 
 AROMATIC ACIDS. The methods pursued in the preparation of these 
 bodies are similar to those employed for the corresponding fatty 
 derivatives. 
 
 Benzoyl chloride C 6 H 5 .COC1, melting at 1 and boiling at 198, 
 is isomeric with the chlorinated benzaldehydes C1.C 6 H 4 .CHO. It is a 
 liquid with penetrating odour. It is formed from benzoic acid, phos- 
 
BENZOYL COMPOUNDS 279 
 
 phorus pentoxide, and hydrochloric acid (B. 2, 80) ; from benzaldehyde 
 and chlorine ; from sodium benzoate and phosphorus oxy-chloride ; 
 and from benzoic acid and phosphorus pentachloride. The action of 
 phosgene and aluminium chloride or oxalyl chloride (B. 41, 3566) upon 
 benzene hydrocarbons, and of anhydrous oxalic acid upon benzo- 
 trichloride (A. 226, 20), are only applicable in the preparation of the 
 chlorides of benzene-carboxylic acids. 
 
 With antimony chloride, benzoic acid combines to form C 6 H 5 COOH. 
 SbQ 5 , m.p. 71, which, on heating, yields benzoyl chloride (B. 35, 
 1117). 
 
 The history of benzoyl chloride, the first-discovered chloride of a 
 carboxylic acid, was given in connection with the fatty acid chlorides 
 (I. 257). Benzoyl chloride is readily accessible and very reactive ; it 
 is therefore one of the most frequently used compounds in various 
 reactions. 
 
 o-, m-, and p-Toluyl chlorides boil at 212, 220, and 95 (10 mm.) 
 respectively. Phenyl-acetyl chloride C 6 H 5 .CH 2 COC1 boils at 102 
 (17 mm.) (B. 20, 1389). 
 
 Benzoyl bromide C 6 H 5 .COBr, melting about o and boiling at 218, 
 results from the action of phosphorus tribromide upon benzoic acid 
 (B. 14, 2473). Benzoyl iodide, consisting of crystalline flakes, is pro- 
 duced when potassium iodide or magnesium iodide acts upon benzoyl 
 chloride (B. 3, 266 ; C. 1909, II. 1132). Benzoyl fluoride, from benzoyl 
 chloride and AgF, boils at 145 . 
 
 So far as concerns properties, benzoyl azimide or benzoyl nitride, to 
 be treated later in connection with benzoyl-hydrazin, attaches itself to 
 the halogen anhydrides of benzoic acid. 
 
 The acid chlorides and haloid anhydrides connect the mixed 
 anhydrides of aromatic acids with inorganic acids. 
 
 Benzoyl nitrate C 6 H 5 COONO 2 , a light yellow oil, is formed by the 
 transformation of benzoyl chloride with silver nitrate at low tempera- 
 tures. On heating, it decomposes into nitric oxides and benzoic 
 anhydride. Water decomposes it into benzoic and nitric acids. It 
 nitrifies aromatic substances (B. 39, 3798). 
 
 Benzoyl nitrite C 6 H 5 COONO, an unstable oil, from silver benzoate 
 and nit rosy 1-chloride (C. 1904, II. 511). 
 
 Benzoic-boric anhydride (C 6 H 5 COO) 3 B, m.p. 145, by heating 
 benzoic acid with aceto-boric anhydride (B. 36, 2224). 
 
 Benzoic-arsenic anhydride (C 6 H 5 COO) 3 As, m.p. 155, on melting 
 benzoic acid with aceto-arsenic anhydride (C. 1906, I. 21). 
 
 3. ACID ANHYDRIDES (I. 259). Benzoic anhydride (C 6 H 5 .CO) 2 O, 
 melting at 42 and boiling at 360, is obtained from benzoyl chloride 
 and sodium benzoate or silver benzoate ; from benzoyl chloride and 
 benzo-trichloride upon digesting them with anhydrous oxalic acid ; 
 from benzoyl chloride by means of lead nitrate (B. 17, 1282) or sodium 
 nitrite (B. 24, R. 371) ; and by the action of concentrated sulphuric acid 
 upon benzo-trichloride (B. 12, 1495). 
 
 Mixed anhydrides are obtained from benzoic acid treated with 
 anhydrides of acid chlorides, pyridin or quinolin (C. 1901, I. 347 ; 
 B. 42, 3483). Aceto-benzoic anhydride C 6 H 5 .COOCOCH 3 , m.p. 10, 
 b.p. 17 I25-I40, decomposes, on heating, into acetic acid and 
 benzoic acid. 
 
280 ORGANIC CHEMISTRY 
 
 Benzoic-earbonie anhydride (C 6 H 6 COO) 2 CO, an oil, from benzoic 
 acid, COC1 2 , and pyridin, yields CO 2 even at ordinary temperatures. 
 
 o- and p-Toluic anhydride, m.p. 37 and 95. Phenyl-aeetie anhy- 
 dride (C 6 H 5 CH 2 CO) 2 O, m.p. 72 (B. 20, 1391). 
 
 4. ACID PEROXIDES. BenzoyI peroxide (C 6 H 5 CO) 2 O 2 , melts at 103 
 and deflagrates when heated. It is formed from benzoyl chloride and 
 barium peroxide, or from benzoyl chloride, hydrogen peroxide, and 
 sodium hydrate (B. 27, 1511 ; 29, 1727 ; 30, 2003 ; 33, 1043). On 
 treating an ether solution of benzoyl peroxide with sodium alcoholate, 
 benzoic ester is produced, together with benzoyl-sodium-hydrogen 
 peroxide : 
 
 (C 6 H 6 CO) 2 O 2 a '-V C 6 H 6 COOC 2 H 5 +C 6 H 5 COOONa ; 
 
 from the latter, even carbonic acid liberates. 
 
 Benzoyl-hydrogen peroxide C 6 HsCOOOH, m.p. 4i-43. It closely 
 resembles hydrogen peroxide. A mixture of benzoyl-hydrogen peroxide 
 and benzaldehyde gives first two molecules benzoic acid. Probably 
 it is also formed in the first phase during the auto-oxidation of benzalde- 
 hyde in air ; a mixture of benzaldehyde and acetic anhydride forms, 
 under the influence of atmospheric oxygen, benzoyl-aeetyl peroxide 
 C 6 H 5 COOOCOCH 3 , m.p. 38, by acetylation of the benzoyl-hydrogen 
 peroxide first formed (B. 33, 1569 ; C. 1902, I. 930). 
 
 5. Tmo- ACIDS AND BiTHio-AciDS. Thio-benzoic acid C 6 H 5 COSH, 
 m.p. 24, is formed by the interaction of benzoyl chloride and alcoholic 
 potassium sulphide ; also, besides triphenyl carbinol, from phenyl- 
 magnesium bromide with COS (B. 36, 1010). Thio-p-toluie acid 
 CH 3 C 6 H 4 COSH, m.p. 44. 
 
 Benzoyl sulphide, thio-benzoic sulphanhydride (C 6 H 5 CO) 2 S, m.p. 48, 
 from two molecules benzoyl chloride with one molecule sodium sulphide 
 (B. 40, 2862). Benzoyl disulphide (C 6 H 5 CO) 2 S 2 , m.p. 130, from thio- 
 benzoic acid on oxidation in ether solution by atmospheric oxygen 
 (A. 115, 27), or from its salts on oxidation by potassium ferricyanide 
 (B. 40, 2862). Thio-benzamide and thio-anilide, see below. 
 
 Dithio-benzoic acid, phenyl-carto-thio-acid C 6 H 5 CSSH, a heavy 
 purple oil, rather unstable, obtained from benzo-trichloride with 
 alcoholic potassium sulphide (A. 140, 240) ; from phenyl-magnesium 
 bromide and CS 2 (B. 39, 3219) ; as well as by the action of hydrogen 
 persulphide and zinc chloride upon benzaldehyde (C. 1909, II. 1780). 
 Methyl ester, b.p. 155 ; ethyl ester, b.p. 167 ; luminous red oils. 
 The lead salt consists of purple flakes, melting at 204-5. The alkali- 
 salt solution gives, by oxidation with iodine, thio-benzoyl disulphide 
 (C 6 H 5 CS) 2 S 2 , m.p. 117, dark-red needles. Dithio-phenyl-aeetie acid 
 CeH 5 CH 2 CSSH, a reddish-yellow oil, from benzyl-magnesium chloride 
 with CS 2 . Lead salt, m.p. 149, yellow needles. 
 
 Phenyl-thio-acetyl disulphide (C 6 H 5 CH 2 .CS) 2 S 2 , m.p. 78 (B. 39, 
 3227). 
 
 Phenyl-p-tolyl-keto-sulphone C 6 H 5 CO.SO 2 C 6 H 4 CH 3 , from benzoyl 
 chloride and sodium-toluol sulphinate, forms a hydrate of m.p 80 
 (C. 1899, II. 719). 
 
 6. ACID AMIDES. The methods of formation and the behaviour of 
 the acid amides have been sufficiently considered in connection with 
 the fatty acid amides. Attention was also called to the fact that the 
 
BENZOYL COMPOUNDS 281 
 
 amides of the carboxylic acids could have two constitution formulae. 
 Thus, benzamide has two formulae : 
 
 I. C 8 H S C< and II. 
 
 The imido-ethers are derived from the second formula (see Silver 
 benzamide). To the methods mentioned under the amides of the 
 fatty acids must be added, in connection with the amides of the 
 benzol-carboxylic acids, their formation through the action of alumi- 
 nium chloride upon aromatic hydrocarbons and urea chlorides. 
 
 Benzamide C 6 H 5 .CO.NH 2 , melting at 130 and boiling at 288, 
 results (i) when benzoyl chloride is acted upon by gaseous or aqueous 
 ammonia, or by ammonium carbonate (see Tribenzamide) ; (2) from 
 benzoic ester and ammonia ; (3) by heating benzoic acid and ammo- 
 nium thio-cyanate to 170 (A. 244, 50) ; (4) by saponification of benzo- 
 nitrile with an appropriate amount of alcoholic potash (C. 1900, 1. 257) ; 
 (5) from urea chloride, benzene, and A1C1 3 (A. 244, 50). It crystallises 
 in pearly flakes, melts at 130, and boils near 288. It is readily soluble 
 in hot water, alcohol, and ether. 
 
 Sodium benzamide C 6 HsCONHNa or C 6 H 5 C(: NH)ONa results from 
 the action of metallic sodium upon benzamide dissolved in benzene 
 (B. 23, 3038). On heating with acid esters it forms mixed diacyl- 
 imides (B. 23, 3038 ; C. 1900, II. 190 ; 1903, I. 157). 
 
 Silver benzamide C 6 H 5 .CO.NHAg or C 6 H 5 .C(: NH).O.Ag, obtained 
 by precipitating the aqueous solution of benzamide and silver nitrate 
 with a calculated amount of sodium hydroxide, is a white crystalline 
 powder. When digested with ethyl iodide it yields benzimido-ethyl 
 ether (B. 23, 1550). 
 
 Dibenzamide (C 6 H 5 CO) 2 NH, melting at 148, is obtained from benzo- 
 nitrile with fuming sulphuric acid, or from benzoyl chloride and benzo- 
 nitrile with aluminium chloride. When distilled under a pressure of 
 15 mm. dibenzamide breaks down into benzo-nitrile and benzoic acid 
 (B. 21, 2389). Sodium dibenzamide (C 6 H 5 CO) 2 NNa is a shining white 
 powder. It is formed when sodium acts upon dibenzamide dissolved 
 in xylol. 
 
 Tribenzamide (C 6 H 5 CO) 3 N, melting at 202, results in the action of 
 benzoyl chloride in ethereal solution upon sodium dibenzamide, and 
 together with benzamide and dibenzamide when benzoyl chloride acts 
 upon ammonium carbonate (B. 25, 3120). 
 
 Benzoyl-chlorimide C 6 H 5 CONHC1 melts at 113. Benzoyl-bromimide 
 C 6 H 5 .CONHBr melts with decomposition at 170. Dibenzamide 
 chloride (C 6 H 5 CO 2 ) 2 NC1, m.p. 89 (C. 1902, II. 359). Methyl- and 
 dimethyl-benzamide C 6 H 5 CON(CH 3 ) 2 melt at 78 and 41. 
 
 N-methylol-benzamide C 6 H 5 CO.NH.CH 2 OH, m.p. 106, from benz- 
 amide and formaldehyde, under the influence of alkaline condensing 
 agents. On heating alone, or in aqueous solution, it easily dissolves 
 into its components. Chromic acid oxidises it to formyl-benzamide 
 C 6 H 5 CONHCHO, m.p. 120. With phenyl-hydrazin the latter gives 
 2, 5-diphenyl-triazol (q.v) (A. 343, 223). Benzoyl-benzylamine C 6 H 5 CO. 
 NH.CH 2 C 6 H 5 , m.p. 105 (B. 26, 2273). 
 
 We get benzanilide C 6 H 5 .CO.NH.C 6 H 5 , phenyl-benzamide, on mixing 
 aniline and benzoyl chloride. It can also be made by the action of 
 
282 ORGANIC CHEMISTRY 
 
 aluminium chloride upon benzene and carbanile, and upon heating 
 benzo-phenoxime (C 6 H 5 ) 2 C : N.OH with concentrated sulphuric acid, 
 acetyl chloride, or glacial acetic acid containing hydrochloric acid, to 
 100, or with glacial acetic acid alone to 180 (B. 20, 2581). Sodium 
 benzanilide, see C. 1900, II. 190. 
 
 When benzanilide is boiled with sulphur it becomes benzenyl-amido- 
 thio-phenol or ju,-phenyl-benzo-thiazole. o~, m-, and p-Benzoyl-toluides 
 C 6 H 6 CONH.C e H 4 CH 8 melt at 131, 125, and 158. 
 
 Diphenyl-benzamide C 6 H 5 CO.N(C 6 H 5 ) 2 , m.p. 177, results from 
 diphenyl-amine and benzoyl chloride, as well as from diphenyl-urea 
 chloride : (i) by condensation with benzene and aluminium chloride 
 (B. 20, 2119) ; (2) by heating with benzoic acid in pyridin solution 
 (B. 41, 636). 
 
 Methylene-dibenzamide, hipparaffin CH 2 (NH.CO.C 6 H 5 ) 2 , m.p. 221, 
 is obtained in the oxidation of hippuric acid with PbO 2 and dilute 
 sulphuric or dilute nitric acid, and results from formaldehyde, benzo- 
 nitrile, and hydrochloric acid (B. 25, 311) ; or from boiling benzamide 
 with formaldehyde and dilute sulphuric acid (A. 343, 226). 
 
 Ethylidene-dibenzamide CH 3 .CH(NHCOC 6 H 5 ) 2 , m.p. 204 (B. 7, 
 
 159). 
 
 Ethylene - dibenzamide C 6 H 5 CO.NH.CH 2 .CH 2 .NH.CO.C 6 H 5 , m.p. 
 
 249, when heated alone, or with hydrochloric acid, yields ethylene- 
 benzenyl-amidine, benzoic acid splitting off at the same time (B. 
 21, 2334). 
 
 Benzoyl-iso-cyanate, carbonyl-benzamide C 6 H 5 CON : CO, m.p. 26, 
 b.p. 10 88, from silver cyanate and benzoyl chloride, yields dibenzoyl- 
 urea in water, and benzoyl-urethane C 6 H 5 CONH.CO 2 C 2 H 5 , m.p. m, 
 in alcohol (B. 36, 3218). 
 
 Hippuric acid, benzoyl-gfycocoll CHa / NH - cac 6 H 6, m . p . 187, de- 
 
 \CO 2 H 
 
 composes at 240 into benzoic acid, benzo-nitrile, and prussic acid. It 
 occurs in considerable amount in the urine of herbivorous animals, in 
 that of the cow and horse ("TTTTOS, horse, and ovpov, urine), and in 
 minute quantities in that of man. Benzoic acid, cinnamic acid, toluol, 
 and other aromatic substances, when taken internally, are eliminated 
 as hippuric acid. It can be obtained artificially (i) by heating benz- 
 amide with monochloracetic acid ; (2) by the action of benzoyl chloride 
 or silver gly co-collide (B. 15, 2740) ; or (3) by adding sodium hydroxide 
 to glycocoll, and shaking with benzoyl chloride (B. 19, R. 307) ; and 
 (4) by heating benzoic anhydride with glycocoll (B. 17, 1662). 
 
 History. Liebig, in 1829, recognised that hippuric acid was a dif- 
 ferent body from benzoic acid, and, to indicate its origin, named it hip- 
 puric acid. In 1839 he established its constitution. Dessaignes (1846) 
 showed that, upon boiling with strong alkalies or acids, it was resolved 
 into glycocoll and benzoic acid (/. pr. Ch. i, 37, 244). In 1848 
 Strecker converted the acid by means of nitrous acid into benzoyl- 
 glycollic acid (A. 68, 54), and in 1853 Dessaignes synthesised hippuric 
 acid from benzoyl chloride and zinc glyco-collide (A. 87, 325). 
 
 Hippuric acid crystallises in rhombic prisms, and dissolves in 600 
 parts cold, and readily in hot water, and alcohol. Boiling acids, or 
 alkalies, decompose hippuric acid into benzoic acid and glycocoll. 
 
 Compare hipparaffin (above), benzoyl-glycollic acid, for other trans- 
 
BENZOYL COMPOUNDS 283 
 
 formations of hippuric acid. Hippuric acid condenses with benzalde- 
 hyde, sodium acetate, and acetic anhydride to benzoyl-amido-cinnamic 
 
 anhydride C 8 H 5 CH .- ^^^^ (A. 337, 265). 
 
 Silver salt C 9 H s AgNO 3 . The ethyl ester melts at 60 (/. pr. Ch. v, 
 15, 247). It is converted by PC1 5 into hippuro-flavin C 1S H 10 O 4 N 2 , 
 consisting of citron-yellow crystals (B. 21, 3321 ; 26, 2324 ; A. 312, 81). 
 Benzaldehyde and sodium acetate change it to benzoyl-amido-cinnamic 
 ester (A. 275, 12). The phenyl ester melts at 104. When boiled with 
 POC1 3 it passes into anhydro-hippuric phenyl ester, melting at 42 
 (B. 26, 2641). 
 
 With formic acid ester and sodium ethylate, hippuric ethyl ester 
 condenses to formyl-hippuric ester C 6 H 5 CO.NH.CH(CHO)CO 2 C 2 H 5 , 
 which is reduced by sodium amalgam to benzoyl-serinic ester C 6 H 5 CO. 
 NH.CH(CH 2 OH)C0 2 C 2 H 5 , m.p. 80. The latter is split up by H 2 SO 4 
 into benzoic acid and i-serin ; with P 2 S 5 it passes into benzoyl-eystein 
 ester C 6 H 5 CONH.CH(CS 2 SH)C0 2 C 2 H 5 , m.p. 185, from which, by 
 saponification with concentrated HC1, we obtain i-cyste'in, or its oxida- 
 tion product, i-cystin (cp. Vol. I., and A. 337, 236). 
 
 Hippuric acid nitrile C 6 H 5 CONHCH 2 CN, m.p. 144, from amido- 
 aceto-nitrile, benzoyl chloride, and NaHO (B. 36, 1646). Hippuryl- 
 hydrazin C 6 H 5 CO.NHCH 2 CO.NH.NH 2 , m.p. 162, from hippuric ethyl 
 ester and hydrazin ; cp. hippuryl-phenyl-buzylene and hippurazide 
 (B. 29, R. 181). 
 
 Benzoyl-alanin C 6 H 5 CONH.CH(CH 3 )COOH, m.p. 166, and benzoyl- 
 a-amido-iso-butyric acid C 6 H 5 CONHC(CH 3 ) 2 COOH, m.p. 198, on 
 heating with acetic anhydride, readily pass into anhydrides resembling 
 
 /^ TT r* _ TO 
 
 lactone : benzoyl-alanin anhydride 5 oZco/ CH ^ CH3 ^ m - p - 39> and 
 
 benzoyl-a-amido-iso-butyric anhydride ^/^ 01 * 3 ^' m -P- 34 ( C P- 
 
 the similarly constituted acyl-anthranilic acids). Ammonia, aniline, 
 and HC1 burst the lactone ring, with formation of the amides, anilides, 
 and chlorides of the corresponding benzoyl-amido-acids. With a- 
 amido-acids they similarly combine to form benzoylated dipeptides, 
 e.g. benzoyl-alanyl-glycocoll C 6 H 5 CONH.CH(CH 3 )CONHCH 2 COOH, 
 Benzoyl-alanyl-alanin C 6 H 5 CONH.CH(CH 3 )CONH.CH(CH 3 )COOH, 
 etc. (J.pr. Ch. 2,81,49,473) 
 
 Benzoyl-asparaginic acid, see B. 43, 661. 
 
 7. ACID HYDRAZIDES. Benzoyl-hydrazin C 6 H 5 CONHNH 2 , m.p. 
 112, from benzoic ester and hydrazin hydrate, or by heating hydrazin 
 benzoate (B. 35, 3240) ; in alkaline solution benzoyl-hydrazin suffers 
 an auto-reduction, leading to benzai-benzoyl-hydrazin C 6 H 5 CONHN : 
 CHC 6 H 5 , and subsequently benzalazin (B. 33, 2561). With excess of 
 benzoic ester hydrazin forms dibenzoyl-hydrazin (C 6 H 5 CO.NH) 2 , m.p. 
 238, also generated by the action of benzoyl chloride upon alkaline 
 hydrazin solutions (C. 1899, I. 1240). On boiling with alcoholic potash, 
 it yields a potassium salt (C 6 H 5 CO) 2 N 2 HK ; the corresponding silver 
 salt with iodine gives azo-dibenzoyl (C 6 H 5 CO) 2 N 2 , m.p. 118 (B. 33, 
 1769). Tri- and tetrabenzoyl-hydrazin, m.p. 206 and 238, are ob- 
 tained by further benzoylation of dibenzoyl-hydrazin (C. 1904, II. 97). 
 
 Sym/benzoyl-phenyf-hydrazin, m.p. 168 (B. 19, 1203), on oxidation 
 
284 ORGANIC CHEMISTRY 
 
 with mercuric oxide or nitrous acid is converted into benzoyl-azo- 
 benzolC 6 H 5 CON 2 C 6 H 5 , red prisms, melting at 80 (C. 1909, II. 84) ; the 
 latter gives with HC1 an addition product which changes into o-chloro- 
 phenyl-benzoyl-hydrazin (B. 30, 319) : 
 
 C C H 5 CONH.NC1C 6 H 5 --- > C 6 H 5 CONHNH[i]C 6 H 4 [2]Cl. 
 
 Unsym. benzoyl-phenyl-hydrazin, m.p. 70 (B. 26, 945, R. 816). 
 
 Dibenzoyl-phenyl-hydrazinC 6 H 5 .CO.N(C 6 H 5 ).NHCOC 6 H 5 , m.p. 177. 
 
 Benzal-benzoyl-hydrazin C 6 H 5 CO.NHN.CHC 6 H 4 , m.p. 203, from 
 benzoyl-hydrazin and benzaldehyde, or from benzalazin with benzoyl 
 chloride (C. 1900, 1. 334). The corresponding silver salt C 6 H 5 CONAgN : 
 CHC 6 H 5 passes with iodine into diphenyl-furo-diazol 
 
 and with benzoyl chloride into diphenyl-benzoyl-dihydro-furo-diazol 
 
 Phenyl-acetic hydrazide, m.p. 116. 
 
 Hydro-cinnamic hydrazide, m.p. 103. 
 
 8. ACIDYL - AZIDES. Benzoyl - azide, benzoyl nitride, azimide, 
 
 ,N 
 C,H 6 CON< ||, m.p. 20, is formed when sodium nitrite, and acetic 
 
 X N 
 
 acid, act upon benzoyl-hydrazin (B. 23, 3023). Its odour is intensely 
 like that of benzoyl chloride ; it volatilises in part with aqueous vapour 
 without decomposition, and explodes with slight detonation upon the 
 application of heat. It is insoluble in water, very soluble in ether, and 
 rather readily soluble in alcohol. It gives a neutral reaction. It 
 breaks down, on boiling with alkalies, into benzoic acid and potassium 
 azo-imide (B. 23, 3029). On heating in benzene solution it is clearly 
 divided up into N 2 and phenyl iso-cyanate : 
 
 /N 
 C 6 H 5 CON< || - > [C 6 H 5 CON<] - > C 6 H 5 N : C : O 
 
 X N 
 
 (B. 42, 2339). 
 
 Heating with alcohol and water leads to the evolution of N 2 , and 
 the formation of the transformation products of phenyl iso-cyanate : 
 phenyl-urethane C 6 H 5 NH.CO.OC 2 H 5 , and carbanilide CO(NHC 6 H 5 ) 2 . 
 Boiling with acid hydrazides yields acidylated semi- car bazides (B. 29, 
 R. 981) : 
 
 C 6 H 5 CON 3 +C 6 H 5 CONHNH 2 == N 2 +C 6 H 5 NHCONHNHCOC 6 H 5 
 
 and p-bromo-benzazide, m.p. 46 (/. pr. Ch. 2, 58, 190). Phenyl- 
 acetic azide C 6 H 5 CH 2 CON 3 and hydro-einnamic azide C 6 H 5 CH 2 CH 2 
 CON 3 with alcohol yield the urethanes of benzyl-amine and phenyl- 
 ethyl-amine (/. pr. Ch. 2, 64, 297). The azides can also be obtained 
 by the action of salts of diazo-benzol upon the acid hydrazides. 
 
 Hippurazide C 6 H 5 CO.NH.CH 2 .CO.N 3 , m.p. 98, results when sodium 
 nitrite and acetic acid act upon hippuryl-hydrazin. It is decomposed 
 by mineral acids, alkalies, ammonia, and amines, with the elimination 
 of hydr azoic acid. When boiled with alcohols, and with water, N 2 is 
 evolved, and there result hippenyl-urethane C 6 H 5 CONHCH 2 NHCOOR 
 and dihippenyl-urea (C 6 H 6 CONHCH 2 NH) 2 CO (B. 29, R. 183). 
 
BENZOYL COMPOUNDS 285 
 
 The action of hippurazide upon glycocoll, glycyl-glycin, alanin, etc. 
 (Vol. I.), gives the benzoyl derivatives of di- and poly-peptides, like 
 C 6 H 5 CONHCH 2 CONHCH 2 COOH, C 6 H 5 CONHCH 2 CONHCH 2 CO.NH 
 CH 2 COOH, C 8 H 5 CONHCH 2 CONHCH 2 CONHCH 2 CONHCH 2 COOH 
 (/. pr. Ch. 2, 70, 57). 
 
 9. NlTRILES OF THE AROMATIC MONOCARBOXYLIC ACIDS. The 
 
 aromatic nitriles are connected by numerous reactions with the prin- 
 cipal classes of the aromatic derivatives. They are produced, like the 
 nitriles of the fatty acids, (i) from the corresponding ammonium salts ; 
 (2) from the corresponding acid amides, by the withdrawal of water 
 with P 2 Os, PC1 6 , and SOC1 2 (B. 26, R. 401) ; (3) by action of bromine, 
 and caustic alkali, upon the primary phenyl-alkyl-amines ; (4) from the 
 aldoximes by the action of acetyl chloride or acetic anhydride. There 
 is also (5) the method of distilling aromatic monocarboxylic acids, with 
 potassium sulpho-cyanide, or, better, with lead sulpho-cyanide (B. 
 17, 1766) : 
 
 2 C 6 H 5 C0 2 H+(CNS) 2 Pb = 2C 6 H 5 CN+2C0 2 +PbS+H 2 S. 
 
 Nuclear - synthetic Methods. (6) The direct replacement of the 
 halogens in the benzol hydrocarbons by the cyanogen group is of 
 exceptional occurrence e.g. when chloro- and bromo- benzol are 
 conducted over strongly ignited potassium ferrocyanide, or when 
 benzol iodide is heated to 300 with silver cyanide, the product being 
 cyano-benzol. 
 
 However, the phenyl-carbinol chlorides e.g. C 6 H 5 CH 2 C1 are as 
 readily transposed, as the alkylogens, into nitriles of the phenyl-fatty 
 acids by means of potassium cyanide. 
 
 The nitriles are also intimately related to the anilines, sulphonic 
 acids, and phenols. Thus, aniline yields (7) phenyl-carbylamine, 
 which, upon the application of heat, is rearranged into the isomeric 
 nitrile. They are also produced (8) on heating the diphenyl-thio-ureas 
 with zinc dust ; (9) by desulphurising the phenyl-mustard oils with 
 copper ; (10) by distilling the formanilides with concentrated hydro- 
 chloric acid or with zinc dust (B. 17, 73) ; (n) by decomposing diazo- 
 benzene chloride with potassium cyanide and copper sulphate. 
 
 (7) 
 
 (8) 
 
 C 6 H 5 NH, (9) 
 
 10 
 
 (ii) 
 
 C 6 H 6 NC 
 
 (C 6 H 5 NH) 2 CS 
 
 C 6 H 6 N : CS 
 
 C.H.NH, 
 S 
 
 C 6 H 6 NH.CHO 
 
 C 6 H 5 N:NC1 
 
 KCN 
 
 C 6 H 5 .C=N. 
 
 N, 
 
 (12) By distilling the alkali-benzene sulphonates with potassium cya- 
 nide or yellow prussiate of potash ; (13) the distillation of the triphenyl 
 phosphates with potassium cyanide or ferrocyanide ; (14) alkyl benzyl- 
 cyanides are formed by the interaction of sodium-benzyl cyanide and 
 alkylogens, C 6 H 5 .CHNa.CN+C 2 H 5 I = C 6 H 5 CH(C 2 H 5 )CN ; (15) the 
 hydrogen atoms of the benzols are directly replaced by the cyanogen 
 group, (a) if cyanogen gas be conducted into the boiling hydrocarbon 
 
286 ORGANIC CHEMISTRY 
 
 mixed with aluminium chloride (B. 29, R. 185) ; (b) in the action of 
 mercury fulminate C : NOHg upon benzene and anhydrous AC1 3 , benzo- 
 nitrile (80 per cent.) is formed, while hydrated A1C1 3 leads to the for- 
 mation of benzaldoxime (B. 36, 10). On the action of chlorine and 
 bromine cyanide upon benzene hydrocarbons in the presence of Al 
 chloride, see B. 33, 1052. 
 
 Properties and Behaviour. The benzo-nitriles are indifferent, agree- 
 ably smelling liquids, or solids with low melting-points. Their reactions 
 are very numerous, but it may be mentioned that boiling alkalies or 
 acids convert them into the corresponding aromatic acids, while nascent 
 hydrogen, best from alcohol and sodium, changes them to primary 
 amines. They yield amide iodides with hydriodic acid. 
 
 They combine with alcohols and HC1 to form imido-ethers, with 
 anilines to amidines, and with hydroxylamine to amidoximes. 
 
 Benzo-nitrile, cyano-benzol C 6 H 5 .CN, boiling at 191, with sp. gr. 
 1-023 (o) is isomeric with phenyl-carbylamine, and is best obtained 
 from benzene-sulphonic acid by method 12, or from benzoic acid by 
 method 5. It is an oil with an odour resembling that of oil of bitter 
 almonds. 
 
 When it is dissolved in fuming sulphuric acid, or boiled with sodium, 
 or acted upon by other condensing agents, benzo-nitrile polymerises 
 to cyano-phenin C 3 N 3 (C 6 H 5 ) 3 . Upon nitration the product is almost 
 exclusively m-nitro-benzo-nitrile. For other transpositions, see 
 Benzo-imido-ethers and Thio-benzamide. 
 
 Alphyl-cyanides : o-, m-, and p-Tolu-nitriles, cyano-toluols CH 3 . 
 C 6 H 4 CN boil at 203, 213, and 218. The p-body melts at 29. 
 p-Xylo-nitrile boils at 231 (B. 18, 1712). 1, 3-Xylo-4-nitrile melts at 
 24 and boils at 222 (B. 21, 3082). Cumo-nitrile (CH 3 ) 2 .CH[4]C 6 H 4 
 [i]CN boils at 244. 
 
 Nitriles of Phenyl-fatty Acids. Benzyl cyanide, phenyl-aceto-nitrile 
 C 6 H 3 .CH 2 CN, b.p. 232, with specific gravity 1-014 ( I S), is isomeric 
 with the three tolu-nitriles. It occurs in the ethereal oil of several 
 cresses (Trop&olum majus and Lepidium sativum) (B. 7, 1293 ; 32, 2335). 
 It is artificially prepared from benzyl chloride with potassium cyanide. 
 It yields toluic acid by saponification ; by reduction /3-phenyl-ethyl- 
 amine is the product, and upon nitration it is chiefly p-nitro-benzyl 
 cyanide which results. 
 
 As in aceto-acetic ester and malonic ester, the hydrogen of the CH 2 
 group, combined with the negative groups C 6 H 5 and CN, is very readily 
 replaced. Thus, sodium ethylate produces the monosodium deriva- 
 tive, which may be transposed by alkylogens to alkyl-benzyl cyanides 
 (see method 14) (B. 21, 1291, R. 197 ; 22, 1238 ; 23, 2070). Nitrous 
 acid, acting upon a sodium ethylate solution of benzyl cyanide, pro- 
 duces iso-nitroso-benzyl cyanide (see Phenyl-glyoxalic acid). Sodium 
 ethylate, acting upon benzyl cyanide and benzaldehyde, produces 
 a-phenyl-cinnamic nitrile C 6 H 5 .C(CN) : CH.C 6 H 5 (B. 22, R. 199). It 
 adds itself to a, jS-unsaturated esters and ketones like Na-malonic 
 ester. 
 
 Methyl-benzyl cyanides, tolyl-aceto-nitriles CH 3 .C 6 H 4 .CH 2 .CN. The 
 o-body boils at 244, the m-body at 241, while the p-compound 
 melts at 18 and boils at 243 (B. 18, 1281 ; 21, 1331). 
 
 j3-Phenyl-propio-nitrile, hydro-cinnamic nitrile C 6 H 5 CH 2 CH 2 CN, 
 
BENZENYL COMPOUNDS 287 
 
 b.p. 261 (corr.) occurs in the ethereal oil of spring-cress, Nasturtium 
 officinal* (B. 7, 520 ; 26, 1971). 
 
 a-Phenyl-propio-nitrile, hydratropic nitrite C 6 H 5 CH(CH 3 )CN, b.p. 
 231 (A. 250, 123, 137). 
 
 In addition to the benzo-nitriles, the classes of bodies 10 to 31 
 arrange themselves with the benzenyl compounds. 
 
 10. Amido - haloids, n. 1 mido - chlorides. 12. Phenyl - hydrazide 
 Imido-chlorides. 
 
 Benzamide chloride C 6 H 5 CC1 2 NH 2 (?) results when hydrochloric 
 acid gas is conducted into an ether solution of benzo-nitrile (B. 10, 
 1891) ; it is probably the first product resulting from the action of PC1 5 
 upon benzamide, which, however, is partly split into benzo-nitrile and 
 HC1, while another part unites with the POC1 3 formed to form phos- 
 phuretted compounds like C 6 H 5 CC1 2 NHPOC1 2 and C 6 H 5 CC1 : NPOC1 2 
 (C. 1909, II. 814). 
 
 Benzamide bromide C 6 H 5 CBr 2 NH 2 , m.p. 70 (A. 149, 307). Benz- 
 amide iodide C 6 H 5 CI 2 NH 2 melts with decomposition (B. 25, 2536) at 
 140. It is produced when benzo-nitrile is poured into concentrated 
 aqueous hydriodic acid. 
 
 Dimettiyl-benzamide chloride C 6 H 5 .CC1 2 .N(CH 3 ) 2 , m.p. 36, from 
 the amide with phosgene or PC1 5 . On heating, the dialkylated benz- 
 amide chlorides split off one or two molecules of chloralkyl and decom- 
 pose into alkyl-benzimide chlorides and benzo-nitrile, the latter being 
 partly polymerised to cyaphenin (B. 37, 2812) : 
 
 C 6 H 5 CC1 2 N(CH 3 ) 2 J C 6 H 5 CC1 : NCH 3 > > C 6 H 5 CN. 
 
 On the utilisation of this reaction for the breaking up of cyclic 
 secondary bases, see Piperidin. 
 
 Benzanilide chloro-iodide C 6 H 5 CC1I.NNC 6 H 5 , m.p. 106 with 
 decomposition, from benzanilide-imido-chloride and HI (C. 1905, 1. 442). 
 
 Methyl-benzimido-ehloride C 6 H 5 CC1 : NCH 3 , from methyl-benzamide 
 with PC1 5 . 
 
 Benzanilide-imido-chloride C 6 H 5 CC1 : N.C 6 H 5 , m.p. 40 and b.p. 310, 
 is produced when PC1 5 acts upon benzanilide (Wallach, A. 184, 79), or 
 upon benzo-phenone oxime (C 6 H 5 ) 2 C=NC1. Water or alcohol will 
 decompose it into hydrochloric acid and benzanilide. For other 
 transpositions of benzanilide-imido-chloride, compare thio- benz- 
 anilide, etc. 
 
 When benzanilide-imido-chloride acts upon sodium aceto-acetic 
 ester, the products are anil-benzyl compounds, /S-ketonic acid deriva- 
 tives, which change to phenyl-quinolin-carboxylic acids upon the 
 application of heat. 
 
 Benzo-phenyl-hydrazide-imido-ehloride C 6 H 5 CC1 : N.NH.C 6 H , m.p. 
 131, is formed when alcohol acts upon the reaction product of PC1 5 
 and sym. benzoyl-phenyl-hydrazin C 6 H 5 .CC1 : N.N(C 6 H 5 )POC1 2 (B. 27, 
 2122). 
 
 Dibenzo-hydrazide chloride C 6 H 6 CC1 : N.N : C1CC 6 H 5 , m.p. 123, 
 from sym. dibenzoyl-hydrazin and PC1 5 . It can easily be transformed 
 .into heterocyclic compounds : (i) On boiling with water it yields 
 diphenyl-furo-diazol ; (2) with P 2 S 5 , diphenyl-thio-diazol ; (3) with 
 ammonia or primary amines, diphenyl-pyrro-diazols ; (4) with hydroxyl- 
 
288 ORGANIC CHEMISTRY 
 
 amine, N-oxy-diphenyl-pyrro-diazol ; (5) with hydrazin, diphenyl- 
 dihydro-tetrazin (/. pr. Ch. 2, 73, 277) : 
 
 Diphenyl-furo- 
 Diphenyl-thio- 
 
 ^N N\ 
 \C1 Cl/ 
 
 NH, 
 
 __ r ,^N.N\_ oDiphenyl-pyrro- 
 
 6 sC \NH / CC H 5 [bbj-diazol 
 
 / /N.N=\ r N-Oxy-c-diphenyl- 
 
 6 ^\N(OH)/ 8 6 pyrro-CbbJ-diazol 
 NH 2 .NH, r M r /N - N\ r N, y-Dihydro- 
 
 NH / ^^6*15 c-diphenyl-tetrazin. 
 
 13. IMIDO-ETHERS OF THE AROMATIC ACIDS (Vol. I.) Theimido-ethers 
 (their HC1 salts) result from the action of HC1 upon a mixture of a 
 nitrile with an alcohol (Pinner, B. 16, 1654; 21, 2650; 23, 2917). 
 Their methyl sulphates are obtained by addition of dimethyl sulphate 
 to primary and secondary acid amides. 
 
 Water decomposes the HC1 imido-ethers into acid esters and 
 ammonium chloride. Benzalkyl-imido-chlorides, with sodium alcohol- 
 ates, change into benzalkyl-imido-ethers. The latter are transposed 
 into tertiary benzamides by the action of alkyl iodides or by heat 
 (C. 1903, I. 833, 876) : 
 
 C 8 H 5 CON(CH 3 ) 2 . 
 
 Sodium amalgam in acid solution reduces benzimido-ether to benz- 
 aldehyde (B. 35, 3039). With ammonia the benzimido-ethers yield 
 benzamidin (q.v.) ; with hydroxylamine, benzamidoxime ; with 
 hydrazin, benzenyl-hydrazidin (q.v.). The following bodies should be 
 viewed as imido-ethers of aromatic carboxylic acids : 
 
 /o CH, c H c 
 
 C H *- C \N-CH 3 C ' H5 - C \N-CH,/ ( ' H ' C ' 
 
 jU-Phenyl-oxazolin. yti-Phenyl-pentoxazolin. /z-Phenyl-benzoxazol. 
 
 Benzimido-methyl ether C 6 H 5 C(NH)OCH 3 , b.p.^ 96, and benzimido- 
 ethyl ether C 6 H 5 C(NH)OC 2 H 5 , b.p. 16 102, are oils precipitated from 
 their chlorohydrates by soda solution. The ethyl ether is also 
 obtained from silver benzamide with ethyl iodide. Similarly, silver 
 dibenzamide gives, with ethyl iodide, benzol-benzimido-ethyl ether 
 C 6 H 5 C(NCOC 6 H 5 )OC 2 H 6 , m.p. 65 (C. 1898, I. 569). n-Methyl-benz- 
 imido-methyl ether C 6 H 5 C(NCH 3 )OCH 3 , b.p. 12 94. 
 
 14. THI AMIDES OF THE AROMATIC ACIDS. Thio-benzamide C 6 H 5 .CS 
 NH 2 or C 6 H 5 C(SH)NH, melting at 116, results on conducting hydrogen 
 sulphide into an alcoholic solution of benzo-nitrile mixed with ammonia 
 (B. 23, 158), and when benzyl-amine is heated to 280 with sulphur 
 (A. 259, 304). Zinc and hydrochloric acid convert it into benzyl- 
 
 N S 
 amine, iodine into dibenzenyl-azo-sulphime (q.v.) C G H 5 G^ ^>C.C 6 H 6 
 
 N- 
 
 (B. 25, 1588), ethylene bromide into /z-phenyl-thiazolin (see 
 below), trimethylene bromide into /x-phenyl-penthiazolin (see Imido- 
 
BENZENYL COMPOUNDS 289 
 
 ethers), and ethylene-diamine into benzenyl-ethylene-diamine (g.v.) 
 
 /NH CH 2 
 C 6 H 5 C/ | (B. 25,2134). Methyl-thio-benzamideC 6 H 5 CSNHCH 3> 
 
 m.p. 79, from phenyl-magnesium bromide and methyl^mustard oil 
 (B. 37, 877). 
 
 Thio-benzanilide C 6 H 5 .CSNH.C 6 H 5 , melting at 98, consists of 
 yellow plates or prisms. It is formed (i) when H 2 S acts upon benzenyl- 
 phenyl-amidine at 100 ; (2) by the action of CS 2 at 110, hydro- 
 sulpho-cyanic acid being simultaneously produced (A. 192, 29) ; (3) 
 when H 2 S acts upon benzanilide chloride ; (4) when P 2 S 5 acts upon 
 benzamide ; (5) from the interaction of phenyl-mustard oil, benzene, 
 and aluminium chloride (B. 25, 3525) (/. pr. Ch. 2, 59, 572) ; (6) from 
 phenyl-mustard oil and phenyl-magnesium bromide (B. 36, 587). It 
 is changed to benzyl-amido-thio-phenol by heat or oxidation. 
 
 Selenium benzamide C 6 H 5 CSeNH 2 , m.p. 102, golden needles, from 
 benzo-nitrile and SeH 2 . Iodine oxidises it to dibenzenyl-azo-selenime 
 
 C,H 5 C^ (B. 37,2550). 
 
 N JN=U.C 6 H 5 
 
 15. IMIDO-THIO-ETHERS OF THE AROMATIC CARBOXYLIC ACIDS are 
 obtained as chlorohydrates from nitriles, mercaptans, and hydrochloric 
 acid (compare Imido-ethers) . The following compounds must be con- 
 sidered as cyclic imido-thio-ethers of benzoic acid : 
 
 S CH 2 S CH 2X s [i] 
 
 /z-Phenyl-thiazolin ^u-Phenyl-penthiazolin //-Phenyl-benzo-thiazol. 
 
 Benzimido-thio-ethyl ether C 6 H 5 C(NH)S.C 2 H 5 is an oil. It readily 
 resolves itself into benzo-nitrile and mercaptan (A. 197, 348). 
 
 By heating sodium xanthogenates with benzalkyl-imido-chlorides in 
 benzene solution the strongly red-coloured imido-xanthides are obtained: 
 Benzo-phenyl-amido-ethyl xanthide C 6 H 5 C(NC 6 H 5 )SCSOC 2 H 5 , m.p. 98, 
 garnet-red prisms (B. 35, 2470). Benzimido-thio-phenyl ether C 6 H 5 
 C(NH)SC 6 H 5 , m.p. 48 (B. 36, 3465)- 
 
 16. AMIDINES of aromatic monocarboxylic acids are obtained from 
 nitriles, imido-ethers, imido-chlorides and thio-amides by means of 
 ammonia and ammonium bases. The cyclic amidins correspond to 
 the cyclic imido-ethers and imido-thio-ethers : 
 
 /NH CH 2 /NH CH 2 
 
 /i-Phenyl-glyoxalidin m-Phenyl-tetrahydro-pynmidin /j-Phenyl-benzimide-azol. 
 Ethylene-benzamidin Trimethylene-benzamidin 
 
 Benzamidine,* benzenyl-amidine C 8 H 6 .C , melting at 75-8o, 
 
 is formed from its hydrochloride C 7 H 8 N 2 .HC1+2H 2 O, consisting of 
 vitreous crystals, melting at 72, which, being anhydrous, become 
 liquid at 169 (A. 265, 130). 
 
 Silver salt C 6 H 5 .C(=NAg)NH 2 . Benzamidine is a stronger base 
 than ammonia. Hydroxylamine converts it, by an exchange of the 
 NH group for the N(OH) group, into an amidoxime. Benzamidine 
 
 * Die Imidodther und ihre Derivate, Pinner, 1892, p. 152. 
 VOL. II. U 
 
290 
 
 ORGANIC CHEMISTRY 
 
 gives with diazo-benzol : benzamidine-diazo-benzol (see below) ; with 
 benzaldehyde : benzal-benzamidine, melting at 175 ; with phenyl-iso 
 cyanide : benzenyl-diphenyl-diureUe C 6 H 5 C(: N.CONHC 6 H 5 ).NHCO.NH. 
 C 6 H 5 , melting at 172 ; with phenyl-mustard oil : benzamidin-phenyl- 
 thio-urea C 6 H 5 .C(: NH).NH.CS.NH.C 6 H 5 , melting at 125; with chloro- 
 carbonic ether: benzamidine-ur ethane C 6 H 5 .C(: NH).NHCO 2 C 2 H 5 , 
 melting at 58 ; heat converts it into diphenyl-oxy-cyanidin ; with 
 phosgene : dibenzamidin-urea CO(NH.C(: NH.)C 6 H 6 ) 2 , melting at 289, 
 and diphenyl-oxy-cyanidin. 
 
 The action of nitrous acid upon benzamidin is very remarkable. 
 The product is benzenyl-dioxy-tetrazotic acid (see below). 
 
 Benzamidin Hetero-ring Formations. Benzamidin heated alone 
 becomes cyano-phenin ; heated with acetic anhydride the product is 
 diphenyl-methyl-cyanidin ; with trimethylene bromide : trimethylene- 
 benzamidin, or ^-phenyl-tetrahydro-pyrimidin ; with acetyl acetone : 
 phenyl-dimethyl-pyrimidin ; with aceto-acetic ester : phenyl-methyl- 
 oxy-pyrimidin : 
 
 /NH 2 
 
 Heat 
 
 (CH 3 .CO) 2 
 
 Cyano-phenin 
 
 Diphenyl-methyl- 
 cyanidin (B. 
 25, 1624) 
 
 BrCH a .CH,.CH,Br 
 
 /NH CH 2 \ Phenyl-tetra- 
 C 6 H 5 .C4 ;>CH 2 hydro-pyrimidin 
 
 ^ N CH 2/ (B. 26, 2122) 
 
 (CH,CO),CH, 
 
 CtL 
 
 Phenyl-dimethyl- 
 
 CH 2 .CO a .C 2 H 5 
 CO.CH, 
 
 \OH 
 
 Phenyl-methyl- 
 oxy-py rimidin . 
 
 Many other amidins besides benzamidin are known ; also numerous 
 alkyl, phenyl, and benzyl substitution products of the simple 
 amidins. As may be gathered from the description of benzamidin, 
 the amidins are unusually reactive bodies, whose investigation has 
 contributed much to the chemistry of the nitrogen-carbon ring 
 systems. 
 
 Phenyl-benzamidin C 6 H 5 C(NH)NHC 6 H 5 , m.p. 114, by the action 
 of sodium upon a mixture of benzo-nitrile and aniline (/. pr. Ch. 2, 
 67, 445). On the acidulation of phenyl-benzamidin and the accom- 
 panying transpositions, see C. 1903, II. 830. 
 
 Diphenyl-benzamidin C 6 H 5 C(NC 6 H 5 )NHC 6 H 5 , m.p. 144, is a 
 chromogen, yielding yellow dyes by the introduction of amido-groups 
 (C. 1898, II. 1049). Trialkyl-benzamidin, see B. 37, 2678. 
 
 17. DIOXY-TETRAZOTIC ACIDS. Free benzenyl-dioxy-tetrazotic acid 
 
 *? H (?) is not known. Its benzamidin salt, melting 
 
 at 178, is produced when nitrous acid acts upon benzamidin. Sodium 
 amalgam reduces the potassium salt to benzenyl-oxy-tetr azotic acid 
 C 7 H 6 N 4 O+H 2 O, melting in anhydrous form at 175 with explosion, 
 
BENZENYL COMPOUNDS 291 
 
 and benzenyl-tetrazotic acid (Lessen, A. 263, 73 ; 265, 129). These 
 bodies belong to the class of heterocyclic tetrazols or pyrro-triazols. 
 
 1 8. HYDRAZIDINS OR AMIDRAZONES of aromatic monocarboxylic 
 acids. Several representatives of the aliphatic phenyl-hydrazidins were 
 discussed in connection with phenyl-hydrazin. The simple aromatic 
 hydrazidins result from the action of hydrazin upon the imido-ethers. 
 The most thoroughly investigated is : 
 
 Benzenyl-hydrazidin C 6 H 6 .C<^ NH * or C 8 H 6 .c<^ H * - This com- 
 
 pound cannot be obtained from its salts in a pure condition. Its 
 benzoyl derivative C 6 H 5 C(: NH)NH.NH.CO.C 6 H 5 melts at 188. It 
 slowly parts with water, even at 120, changing into c-diphenyl-triazol, 
 whereas nitrous acid converts it into dibenzenyl-isaoxime or diphenyl- 
 furo- (bbj-diazol. 
 
 In addition to benzenyl-hydrazidin, produced in the interaction of 
 hydrazin and benzimido-ether, there also result : 
 
 Dibenzenyl-hydrazidin C 6 H 5 .C(: NH).NH.NH(NH :)C.C 6 H 5 or C 6 H 5 
 C(NH 2 ) : N N : (NH 2 )C : C 6 H 5 , melting at 202, and diphenyl-dihydro- 
 tetrazin (q.v.). Nitrous acid changes benzenyl-hydrazidin into phenyl- 
 tetrazotic acid (q.v.) : 
 
 r /NH.NH 2 Benzenyl- 
 
 (~ * CeM5 - C \NH hydrazidin 
 
 r TT r/ OC 2 H s NH,NH, r H r /NH 2 NH 2 \ c c H Dibenzenyl- 
 
 \ - > C H '- C \N _ N/^ 6 ' hydrazidin 
 
 /NHNH-x Diphenyl-dihydro- 
 
 > ^'"s' __ /?" * $ tetrazin 
 
 ~/N.NH 2 NOOH r r /"N NH c-Phenyl-tetrazotic 
 
 CeH5 ' C \NH 2 CeH6 - C \N=]fT acid 
 
 -Diphenyl-triazol 
 
 N-NH _ f ~ - . 
 
 NH 2 COC 6 H 6 \NOQH r /N N Dibenzenyl-isazoxime 
 
 6 5 \O _ C.C 6 H 5 Diphenyl-furo^bb^-diazol. 
 
 Diphenyl-dihydro-tetrazin is readity rearranged by acids into 
 iso-diphenyl-dihydro-tetrazin. It oxidises on exposure to the air to 
 diphenyl- tetrazin (Pinner, B. 27, 3273 ; 28, 465 ; A. 297, 221 ; 298, i) : 
 
 /NH N\ /NH-NH\ O /N=N\ 
 
 19. NlTRAZONES, NlTROSAZONES OR PHENYL - AZOXIMES. These 
 
 derivatives of the benzoic acids are obtained by the same methods as 
 are the corresponding aliphatic derivatives. 
 
 Benzenyl - nitrazone, phenyl - nitro - formaldehydrazone, 
 
 C6H5C \NNHC 8 H 5 and C ' HfiC \NNC 8 H 5 ' m ' P ' IO2 ' 1S fOmied fr m P 116 ^ 1 ' 
 nitro-methane, or from nitro-methane itself, by the action of diazo- 
 benzol. It is best obtained from benzaldehyde-phenyl-hydrazone with 
 amyl nitrite or N 2 O 4 (C. 1908, II. 945) ; an intermediate product is 
 benzenyl-nitrosazone C 6 H 5 C(NO) : NNHC 6 H 5 , with its more stable 
 
 transposition product, phenyl-azo-benzaldoxime C H 5 C \NNC H ' m ' p> 
 135. This is obtained from benzaldehyde-phenyl-hydrazone with 
 amyl nitrite and pyridin. Reduction with Am 2 S converts phenyl- 
 
292 ORGANIC CHEMISTRY 
 
 mtro-formaldehydrazone first into phenyl - hydrazo - benzaldoxime 
 C 6 H g C(NOH)NHNHC 6 H 5 , and this is oxidised by ferric chloride to 
 phenyl-azo-benzaldoxime. The methyl ester of phenyl-nitro-formalde- 
 hydrazone C 6 H 6 C(NOOCH 3 ) : NNHC 6 H 5 , m.p. 92, breaks up, on boiling 
 with alcohol, into formaldehyde and phenyl-azo-benzaldoxime (B. 34, 
 2019 ; 35, 1091 ; 36, 62, 90). m-Nitro-benzenyl-nitrosazone NO 2 C 6 H 4 
 C(NO) : NNHC 6 H 5 , m.p. 98 with decomposition, is transposed by 
 sodium ethylate, or pyridin, into phenyl-azo-m-nitro-benzaldoxime 
 NO 2 C 6 H 4 C(NOH).N : NC^, m.p. 183 with decomposition. The 
 nitrosazones easily lose nitric oxide, even when boiled with ether, and 
 the residues undergo various condensations (B. 36, 92). 
 
 20. FORMAZYL DERIVATIVES OF THE AROMATIC MONOCARBOXYLIC 
 
 ACIDS. Formazyl-benzol C 6 H 5 C = -* m.p. 173, consists of 
 
 x'JN - JN XT.v^giric* 
 
 red flakes with a greenish metallic reflex. It is produced (i) when diazo- 
 benzolin alkaline solution (B. 27, 1690) acts upon benzaldehyde-phenyl- 
 hydrazone ; (2) from benzenyl-amidoxime and phenyl-hydrazin (B. 27, 
 I 6o) ; (3) when phenyl-hydrazin and benzo-phenyl-hydrazide-imide 
 chloride interact. The hetero-ring formations of the formazyl com- 
 pounds have been described. A glacial acetic acid solution of sulphuric 
 acid converts formazyl-benzol into pheno-phenyl-triazin (q.v.). It 
 yields triphenyl-tetrazolium hydroxide upon oxidation : 
 
 C,H 6 NH 2 r /N=N [i]\~ TJ Phene-phenyl- 
 
 H < triazin 
 
 ^N NC 6 H 6 hydroxide. 
 
 Guanazyl- benzol C 6 H 5 C2 NH , orange-yellow prisms, 
 
 \.N . -NUjJtlg 
 
 melting at 199. It is formed when diazo-benzol chloride acts 
 upon benzal-amido-guanidin, the condensation product derived from 
 benzaldehyde and amido-guanidin. Nitric acid oxidises guanazyl- 
 benzol to diphenyl-tetrazol (B. 30, 444). 
 
 21. HYDROXAMIC ACIDS, THEIR ETHERS AND ESTERS. Under benz- 
 amide mention was made of the two structural formulae which were 
 theoretically possible for benzamide : the benzamide formula and the 
 benzimido-acid formula. If we suppose, in these formulae, a hydrogen 
 atom in union with nitrogen to be replaced by the hydroxyl group, 
 we arrive at the two formulae theoretically possible for a hydroxamic 
 acid : 
 
 r TT r/ NH 2 r w r-/ NH . r TT r/NHOH . r 
 
 C H '- C \0 CeH ' C \OH' C ' H6C \0 C6 
 
 Benzamide Benzo-hydroxamic acid. 
 
 The amido-formula is preferred for the amides of the carboxylic 
 acids ; the imido-ethers are derived from the imido-acid formula. The 
 oximido-acid formula is, however, more probable for the benzo-hydrox- 
 amic acids. Hydro xime-acid chlorides correspond to the imide 
 chlorides, and amidoximes to the amidines. Although hydroxamic 
 acid, and its homologues, are known in but one form each, many ethereal 
 derivatives of the hydroxamic acids occur in several similarly consti- 
 tuted modifications, whose observed difference can in no satisfactory 
 
BENZENYL COMPOUNDS 293 
 
 way be attributed to structural difference (W. Lessen, A. 281, 169). 
 Just as in the case of the oximes, so here the isomeric phenomena of 
 benzo-hydroxamic acid ethers are referred to the stereo-chemistry of 
 nitrogen. 
 
 a- and /2-Ethyl-benzo-hydroxamic acids differ from each other by 
 the following space-formulas (Werner, B. 25, 33) : 
 
 C 6 H 5 .C OC 2 H 5 Ethyl-syn-benzo- C 6 H 6 .C OC 2 H 5 Ethyl-anti-benzo- 
 
 hydroxamic acid (a-) N.OH hydroxamic acid (ft-). 
 
 Crystallographic studies have shown that many classes of amide-like 
 derivatives of hydroxylamine appear in polymorphous modifications. 
 
 Benzo-hydroxamie aeid C 6 H 5 .C(: NOH).OH, m.p. 124, and dibenzo- 
 hydroxamie acid or benzoyl-benzo-hydroxamic ester C 6 H 5 C(: NO. 
 COC 6 H 5 )OH, m.p. 161, are produced by the interaction of benzoyl 
 chloride and hydroxylamine. Benzo-hydroxamic acid is also formed 
 by oxidation of benzaldoxime with Caro's acid ; from phenyl-nitro- 
 methane C 6 H 5 CH 2 NO 2 ; by isomerisation by means of alkali ; from 
 benzaldehyde by transposition with benzol-sulphydroxamic acid, or 
 with mtro-hydroxylaminic acid (B. 34, 2023 ; 35, 51 ; C. 1901, II. 99, 
 770 ; 1904, I. 24). If silver benzoate is made to act upon benzo- 
 hydroximic chloride, an isomer of dibenzo-hydroxamic acid is first 
 formed, melting at 95, and this easily transposes into an isomer of 
 higher m.p., incidentally splitting off benzoic acid, and forming a 
 certain quantity of diphenyl - furoxane. A few substituted benzo- 
 hydroximic chlorides only yield the corresponding diphenyl-furoxanes 
 (B. 32, 1654). On heating benzo-hydroxamic acid with thionyl chloride 
 in benzene solution, we get phenyl iso-cyanate, with intramolecular 
 atomic displacement (C. 1907, I. 633) : 
 
 C 6 H 5 C(: NOH)OH+SOC1 2 = C 6 H 5 N : C : O-j-SO 2 +2HCl. 
 
 The potassium salt of the dibenzo-hydroxamic acid is decomposed 
 by water, especially on heating, into potassium benzoate, s-diphenyl- 
 urea, and CO 2 : 
 
 2 C 6 H 5 C( : NOCOC 6 H 5 ).OK+H 2 = 2C 6 H 5 COOK+CO(NHC 6 H 5 ) 2 +CO 2 . 
 
 Other acidyl derivatives of benzo-hydroxamic acid behave similarly ; 
 on heating with ammonia they yield monophenyl-urea ; with alcohol, 
 phenyl-ure thane, i.e. transformation products of phenyl iso-cyanate 
 (A. 309, 189). 
 
 The rearrangement occurring here recalls that of ketoximes (Beck- 
 mann, p. 189) to alky Used acid amides. As s-diphenyl-urea can be 
 resolved by hydrochloric acid into aniline and CO 2 , it is possible, aided 
 by these reactions, which are capable of greater generalisation, to 
 change benzoic acid to aniline that is, to replace the CO 2 H group by 
 the NH 2 group (A. 175, 313 ; compare benzoyl azide). The alkyl 
 ethers of dihydroxamic acid are known in two modifications : 
 a-(syn)-methyf ether, m.p. 53; -(anti) -methyl ether, m.p. 55; 
 a-(syn)-ethyl ether, m.p. 58 ; jS-(anti) -ethyl ether, m.p. 63 (A. 205, 
 281 ; 281, 235). The a-bodies result from the action of alkyl iodides 
 upon the silver salts ; the jS-compounds through the action of benzoyl 
 chloride and caustic potash upon the alkyl-hydroximic acids. 
 
 Benzo-hydroximie acid alkyl ethers or alkyl-benzo-hydroximie 
 
294 ORGANIC CHEMISTRY 
 
 acids C 6 H 5 C(: NOH)OR' are obtained from benzimido-ethers and 
 hydroxylamine hydro-chloride, and from dibenzo-hydroxamic acid 
 alkyl ethers (A. 252, 211). They occur in two modifications, which 
 can be distinguished by the fact that the a- or syn-modifications 
 yield on treatment with PC1 5 (by Beckmann's transposition) phenyl- 
 carbamic acid ethers, or their transposition products : 
 
 C 6 H 5 COCH 3 OCOCH 3 
 
 HO tf * C 6 H 5 ttH 
 
 whereas the j8- or anti-forms become phosphoric ethers of the alkyl- 
 benzo-hydroximic acids (B. 29, 1146). a- (syn) -Methyl ether, m.p. 64, 
 readily changes to a physical isomeride, also belonging to the syn- 
 modification, m.p. 101 (B. 29, 1150). jS-(anti) -Methyl ether, m.p. 
 44 ; a-(syn)-ethyl ether, m.p. 53 ; and jS-(anti) -ethyl ether, m.p. 68. 
 
 The alkyl-benzo-hydroximic acids also form alkyl and acidyl ethers. 
 Tribenzoyl-hydroxylamine C 6 H 5 .C(: NOCOC 6 H 5 )O.COC 6 H 5 is produced 
 in three forms when benzoyl chloride acts upon hydroxylamine chloro- 
 hydrate : a-modification, m.p. 100 ; /^-modification, m.p. 141 ; and 
 the y-modification, m.p. 112. Hydrochloric acid changes the a- and 
 /-modifications into the j8-form (A. 281, 276). 
 
 Thio-benzo-hydroxamic acid C 6 H 5 C^ , an unstable oil, is formed 
 
 by the action of hydroxylamine upon dithio-benzoic acid. The di- 
 benzoyl compound melts at 92 (C. 1909, II. 1552). 
 
 22. HALOIDS OF BENZO-HYDROXAMIC ACID. The free chlorides, as 
 well as the ethers of the fluorides, chlorides, and bromides, are known. 
 The free chlorides result from the corresponding benzaldoximes upon 
 treatment with chlorine in chloroform solution. The ethers are pro- 
 duced when the amidoxime ethers are treated with haloid acids and 
 an alkaline nitrite ; also when PC1 5 acts upon the alkyl ethers of 
 hydroxamic acid (A. 252, 217). The hydroximic chlorides with 
 ammonia yield atnidoximes ; with hydroxylamine, hydroxam-oximes ; 
 on standing, or, rapidly, on heating, they are decomposed to form 
 azoximes (q.v.) and nitriles ; with sodium carbonate they split off HC1 
 and yield nitrile oxides. For transposition with silver salts; see B. 32, 
 
 1975. 
 
 Benzo-hydroximic acid chloride C 6 H 5 C( : NOH)C1, melting at 48, 
 from benzaldoxime, is converted by ammonia into benzenyl-amidoxime 
 (B. 27, 2193, 2846). Benzenyl-methoxime chloride C 6 H 5 .C( : NOCH 3 )C1, 
 boils at 225. Benzenyl-ethoxime bromide C 6 H 5 .C( : NOC 2 H 5 )Br boils 
 
 at 239 (B. 24,3454)- 
 
 Benzenyl-hydroxylamine-acetic acid C 6 H 5 .C( : NOCH 2 .CO 2 H).OH, 
 melting at I35-I38, is formed when caustic potash acts upon ben- 
 zenyl-nitroxime-acetic acid C 6 H 5 .C( : NO.CH 2 CO 2 H)ONO, melting at 
 95. The latter is produced through the action of sulphuric acid and 
 potassium nitrite upon benzenyl-amidoxime-acetic acid (see below). 
 Benzenyl-fluor-, chlor-, and bromoxime-acetic acids all melt at 135. 
 They are obtained when haloid acids and an alkaline nitrite are allowed 
 to act upon benzenyl-amidoxime-acetic acid (B. 26, 1570). 
 
 23. BENZO-NITROLIC ACID C 6 H 5 C \^Q H ' tight-y el l w needles, of very 
 bitter taste, m.p. 58, is formed, besides benzaldoxime peroxide, by 
 the action of HNO 2 upon phenyl-iso-nitro-methane, and, in small 
 
BENZENYL COMPOUNDS 295 
 
 quantity, by oxidation of benzo-nitrosolic acid with KMnO 4 (B. 39, 
 2522). It is much more unstable than the paraffin-nitrolic acids, and 
 easily decomposes on standing, doing so instantly on heating with HNO 2 
 and diphenyl-furoxane (q.v.), with intermediate formation of benzo- 
 nitrile oxide. In alkalies it dissolves with an orange coloration. The 
 solutions of the alkali salts decompose spontaneously into alkali nitrite 
 and tribenzo-nitrile oxide. 
 
 24. BENZO-NITROSOLIC ACID C 6 H s\Q is obtained in the form of 
 
 its dark-blue salts, by the action of aqueous alkalies, or ammonia, 
 upon benzo-hydroxame oxime, with intermediate formation of the very 
 
 unstable red azo-compound C 6 H 5 C^^ ^/CC 6 H 5 , which is split up, 
 
 by hydrolysis, into benzenyl-amidoxime and benzo-nitrosolic acid. 
 The free acid is not stable ; liberated from its salts, it decomposes 
 into HNO 2 and benzo-nitrile. The action of iodine upon the silver 
 salt (pink needles, decomposing at 94) produces diphenyl-furoxane 
 (B. 39, 1480). 
 
 25. NITRILE OXIDES. The nitrile oxides contain the atomic group 
 .N 
 
 C^ i and may therefore be regarded as anhydrides of the hydrox- 
 
 amic acids, with which they are in close genetic connection. 
 
 ^N 
 Benzo-nitrile oxide C 6 H 5 C^ | forms a mobile oil, of a penetrat- 
 
 ing odour, resembling nitrile. At a low temperature it solidifies in 
 a crystalline mass, melting at 15. It is obtained by withdrawing 
 HC1 from benzo-hydroximic chloride by means of sodium carbonate 
 (B. 40, 1667). On keeping, it quickly polymerises to diphenyl-furoxane 
 
 C6H5 N^\0 6H5 ' On heatin & in x y lcl solution it partly isomerises 
 to phenyl iso-cyanate (B. 42, 4207). Concentrated HC1 splits it up into 
 benzoic acid and hydroxylamine,while zinc dust and glacial acetic acid 
 reduce it to benzo-nitrile. With methyl-magnesium iodide it combines 
 to form aceto-phenone oxime : 
 
 C 6 H 5 C^ .EM?i. C 6 H 5 C( : NOMgI)CH 3 *-> C 6 H 5 C( : NOH)CH 3 . 
 
 A trimeric body of benzo-nitrile oxide is formed by the spontaneous 
 decomposition of an aqueous solution of sodium benzo-nitrolate, with 
 splitting off of sodium nitrite. 
 
 / /N\ 
 
 Tribenzo-nitrile oxide C 6 H 5 C< | is decomposed at 130, with 
 
 \ X 0/3 
 
 explosion when rapidly heated. In its transformations it resembles 
 the monomeric compound. Heating in toluol solution depolymerises 
 it, with formation of phenyl iso-cyanate ; with aniline , it yields 
 diphenyl-urea, by reduction, benzo-nitrile. Alcoholic HC1 splits it, 
 partly into benzoic acid and hydroxylamine, and partly transforms it 
 
 intodibenzenyl-azoxime^ tt ?''\~ -H5 (B. 42, 806). 
 
 C'g.H.gC/ IN O 
 
 26. THE AMIDOXIMES are produced by the action of hydroxylamine 
 upon thio-amides, nitriles, imido-ethers, and amidines. Ferric chloride 
 imparts a deep-red colour to the alcoholic solution of the amidoximes. 
 
296 ORGANIC CHEMISTRY 
 
 Benzenyl - amidoxime, amide of benzo - hydroxamic acid 
 C 6 H 6 .C^[^ H ), melts at 79. It gives the iso-nitrile reaction with 
 
 chloroform and potassium hydroxide. Nitrous acid changes it to 
 benzamide. With acids and caustic alkalies it yields salts -e.g. 
 C 6 H 5 .C( : N.OH)NH 2 .HC1 and C 6 H 5 .C(NH 2 ) : N.OK. Alkyl iodides 
 convert the latter into amidoxime ethers. 
 
 Methyl ether C 6 H 5 (.NH 2 ) : NOCH 3 melts at 57 ; the ethyl ether 
 melts at 67 (A. 281,28o). 
 
 Acetyl-benzenyl-amidoxime C 6 H 5 .C( : NOCOCH 3 ).NH 2 melts at 
 16 (B. 18, 1082). Benzenyl-oximido-carbonic ester C 6 H 4 C(.NH 2 ) : 
 NOCO 2 C 2 H 5 melts at 127. Benzenyl-oximido-glyeollic acid C 6 H 5 . 
 C(.NH 2 ) : NO.CH 2 .CO 2 H melts at 123. Benzenyl-amidoxime-butyric 
 acid C 6 H 5 C(NH 2 ) : NOCH(C 2 H 5 )COOH melts at 82 (B. 29, 2655). 
 
 Hetero-ring Formations of the Amidoximes. (i) The amidoximes 
 condense with the aldehydes of the fatty series to hydrazoximes. The 
 amidoxime acid derivatives, alluded to above, throw off, on heating 
 above their melting-points, water or alcohol, and become azoximes : 
 
 /NH 2 +CH,CHO r TT r /NH_ . Benzenyl hydraz- 
 
 ~ -CH.C ,H.CH 3 oxime _ ethidene 
 
 -H 2 O r TT ~/N=^\ Ethenyl-benzenyl- 
 
 . C 6 H 5 .C^ N _ X C .CH 3 azoxime 
 
 r IT r/ NH 2 -C 2 H 5 OH r TT /NH_. Carbonyl-ben- 
 
 CeH5 - C \N.O.CH 2 .C0 2 H~ ' CeH5 ' C \N >( zenyl-azoxime 
 
 p TT r /NH 2 H 2 O r TT r /NH CO^^ Benzenyl-amidoxime- 
 
 U6ll5 - C \N.O.CH 2 .C0 2 H ~ ' UeH5 - C \N - O - ' H2 glycollic acid. 
 
 There is a distinction between the amidoximes and the oxy-amidins, 
 which have the same tautomeric fundamental form : 
 
 _ C /-NOH d /NHOH 
 
 '\NH - 
 
 Oxy-amidins are produced from imido-chloride with j8-aryl-hydro- 
 xylamines (B. 34, 2620 ; 36, 18). Benzenyl-phenyl-p-tolyl-oxy-amidin 
 C 6 H 5 C(NC 6 H 5 )N(C 7 H 7 )OH, m.p. 175, and benzenyl-p-tolyl-phenyl-oxy- 
 amidin C 6 H 5 C(NC 7 H 7 )N(C 6 H 5 )OH, m.p. 191, on reduction with H 2 SO 3 , 
 form the same phenyl-tolyl-benzamidin. 
 
 27. HYDRAZIDOXIMES result from benzo-hydroximic chloride, and 
 hydrazin hydrate, in alcoholic solution. Like the amidoximes, they 
 possess an amphoteric character, and dissolve in acids as well as in 
 alkalies. The latter readily decompose them, with liberation of nitrogen. 
 
 Benzenyl-hydrazidoxime c e H 4C^^ H , rn.p. 110 with decom- 
 
 position, yields N-oxy-c-phenyl-tetrazol with nitrous acid. With 
 benzaldehyde it condenses to benzal-benzenyl-hydrazidoxime C 6 H 5 C 
 ( : NOH)NH.N : CHC 6 H 5 , m.p. 120, which, with acids, is easily 
 anhydrated into ccj-diphenyl-triazol (B. 42, 4199) : 
 
 /NOH NOOH TT r ,/N(OH).N 
 
 ' N-Oxy-c-phenyl-tetrazol 
 
 c fCl -Diphenyl-triazol. 
 
DERIVATIVES OF ORTHOBENZOIC ACID 297 
 
 28. HYDROXAMOXIMES. Benzo-hydroxamoxime, benzenyl-oxy-ami- 
 doxime C 6 H 5 C(NOH)NHOH, m.p. 115 with decomposition, is formed 
 from benzo-hydroximic chloride with hydroxylamine ; it yields a 
 reddish-brown copper salt (C 7 H^ 2 O 2 ) 2 Cu (B. 31, 2126). Alkalies 
 convert it into a red azo-body, which is further hydrolysed to benzenyl- 
 amidoxime and the salts of benzo-nitrosolic acid (B. 39, 1480). 
 
 DERIVATIVES OF ORTHOBENZOIC ACID. 
 
 29. Ethyl - orthobenzoie ester, ethyl ortho-benzoate, benzenyl - ethyl 
 Ether C 6 H 5 C(O.C 2 H 5 ) 3 , from phenyl-chloroform and sodium ethylate, 
 boils at 220-225, or from phenyl-magnesium bromide and ortho-car- 
 bonic ester (B. 38, 564). 
 
 30. Benzo-triehloride, phenyl-chloroform, benzoic acid trichloride, 
 benzenyl trichloride C 6 H 5 CC1 3 , melting at 22-5 (B. 26, 1053), boiling 
 at 213, with sp. gravity 1-38 (i4), is isomeric with the chloro- 
 benzal chlorides, dichloro-benzyl chlorides, and the trichloro-toluenes. 
 Phenyl-chloroform bears the same relation to benzoic acid or phenyl- 
 formic acid that methyl-chloroform bears to acetic acid or methyl 
 formic acid (I. 256). It results (i) upon conducting chlorine into 
 boiling toluol, until there is no further increase in weight (A. 146, 
 330) ; (2) by the action of phosphorus pentachloride upon benzyl 
 chloride (A. 139, 326). It changes to benzoic acid when heated to 
 100 with water. It yields benzoyl chloride and benzoic anhydride on 
 being digested with anhydrous oxalic acid (A. 226, 20). It readily 
 condenses to triphenyl-methane derivatives, with the anilines and 
 phenols (B. 15, 232 ; A. 217, 223). 
 
 Benzo-trifluoride C 6 H 5 CF 3 , b.p. 103, is formed besides difluoro- 
 chloro-toluol C 6 H 5 CC1F 2 , b.p. 143, from benzo-trichloride and antimony 
 trifluoride (C. 1898, II. 26). 
 
 31. Ortho-benzoie acid piperidide C 6 H 5 C(N.C 5 H 10 ) 3 , m.p. 80, is 
 produced on warming benzo-trichloride and piperidin. 
 
 The benzamide haloids also belong to the derivatives of ortho- 
 benzoie acid. 
 
 (c) SUBSTITUTED AROMATIC MONOCARBOXYLIC ACIDS. 
 
 Only those will be given in connection with the monocarboxylic 
 acids in which the substitution has occurred with the hydrogen atoms of 
 the benzene nucleus. Certain ortho-products show the power, by water 
 elimination, of yielding inner anhydrides or heterocyclic compounds. 
 
 See above for the behaviour of 2, 6-substituted car boxy lie acids in 
 their esterincation with alcohol and hydrochloric acid. 
 
 i. Halogen Benzoic Acids are formed : 
 
 (1) By the substitution of benzoic acids or nitriles ; the halogen 
 atom entering first prefers the meta-position with reference to car- 
 boxyl. 
 
 (2) By oxidising p- and m-halogen toluols and higher homologues 
 with chromic acid, and o-haloid hydrocarbons with dilute nitric acid 
 or potassium permanganate. In the animal organism the halogen 
 toluols are transformed with the corresponding halogen-substituted 
 hippuric acids (C. 1903, I. 411). 
 
298 ORGANIC CHEMISTRY 
 
 (3) From the amido-acids by means of (a) the diazo-sulphates, or 
 (b) the diazo-amido-acids ; both classes, when boiled with haloid acids, 
 have been obtained from the diazo-amido-benzoic acids (B. 15, 1197). 
 
 (4) By the action of phosphorus pentachloride upon the oxy-acids 
 (compare salicylic acid). 
 
 (5) Nuclear synthesis : heating the halogen nitro-benzols to 200- 
 230 with potassium cyanide and alcohol, In (his reaction the cyano- 
 gen group replaces the nitro-group ; it does not, however, take the same 
 position in the benzene residue (B. 8, 1418). At the temperature of 
 the reaction the nitrile changes to the acid. m-Chloro-nitro-benzol 
 yields o-chloro-benzoic acid ; and p-chloro-nitro-benzol, m-chloro- 
 benzoic acid. 
 
 (6) From the haloid anilines through the diazo-compounds, etc. 
 Properties and Behaviour. In the following tabulation of the melt- 
 
 ing-points of the monohaloid benzoic acids it will be observed that the 
 ortho-bodies melt at the lowest temperatures, and the para-compounds 
 at the highest. The melting-point rises with the atomic mass of the 
 substituting halogen. The ortho-derivatives are fairly readily soluble 
 in water, and easily yield soluble barium salts, whereby they can 
 usually be quite readily separated from the meta- and para-derivatives. 
 When they are fused" with caustic potash, oxy-benzoic acids result. 
 With NH 3 , or amines and copper, o-chloro-benzoic acid is transposed 
 into anthranilic acid and n-alkyl-anthranilic acids (A. 355, 312). 
 
 Fluoro-benzoie acid : o-, m.p. 120 : m-, m.p. 124 ; p-, m.p. 182 
 
 Chloro-benzoie acid : o-, 137 ; m-, 153 ; p-, ,, 240 
 
 Bromo-benzoie acid : o-, 147 : m-, 155 ; p-, ,, 251 
 
 lodo-benzoie acid : o-, ,, 162 ; m-, 187 ; p-, 265. 
 
 Numerous poly-chloro- and poly-bromo-benzoic acids are known. 
 The five hydrogen atoms of the phenyl of benzoic acid can be replaced 
 by chlorine or bromine. 
 
 2. lodoso- and lodo-benzoic Acids. Upon chlorinating the three 
 iodo-benzoic acids in chloroform, three iodo-chloro-benzoic acids are 
 produced. Sodium hydroxide changes these to the iodoso-benzoic acids 
 (B. 27, 2326). o-Iodoso-benzoic acid C 6 H 4 (IO)CO 2 H consists of bril- 
 liant flakes, which explode at 244. This acid is also produced in the 
 oxidation of o-iodo-benzoic acid with fuming nitric acid (B. 28, 83), and 
 together with o-iodo-benzoic acid C 6 H 4 (IO 2 )CO 2 H, exploding at 230 
 with violence, when o-iodo-benzoic acid is oxidised with potassium per- 
 
 mangate. The formula C 6 H 4 { _^>O has also been suggested for 
 
 the o-iodoso-benzoic acid, as it yields, like laevulinic acid, when heated 
 with acetic anhydride, an acetyl derivative : acetiodoso-benzoic acid 
 
 , melting at 166 (B. 26, 1364). 
 
 3. Nitro-monoearboxylic Acids. Not more than three nitro-groups 
 have been introduced into the benzene residue of an aromatic carboxylic 
 acid. 
 
 Nitro-benzoic Acids. (i) Meta-nitro-benzoic acid is the principal 
 product in the nitration of benzoic acid. The quantity of the ortho- (20 
 per cent.) and para- (1-8 per cent.) acids is less (A. 193, 202). (2) By 
 oxidising the three nitro-toluols ; the ortho- with potassium permangan- 
 
NITRO-MONOCARBOXYLIC ACIDS 299 
 
 ate (B. 12, 443), and the meta- and para- with a chromic acid mixture 
 (A. 155, 25). o- and p-Nitro-benzoic acids are also produced by oxidis- 
 ing o- and p-nitro-benzyl chloride with potassium permanganate (B. 17, 
 385), as well as by oxidising o- and p-nitro-cinnamic acids. (3) By 
 converting the three isomeric nitranilines into the three nitro-benzo- 
 nitriles (B. 28, 150). The nitration of o-benzo-nitrile yields m-nitro- 
 benzo - nitrile almost exclusively. o-Nitro-benzo-nitrile has been 
 obtained from o-nitraniline (B. 28, 151). Nitro-acids result upon 
 saponifying the nitro-nitriles with caustic soda : 
 
 o-Nitro-benzoic acid melts at 147 ; o-Nitro-benzo-nitrile melts at 109 
 m-Nitro-benzoic acid ,, 141 ; m-Nitro-benzo-nitrile 116 
 p-Nitro-benzoic acid ,, 238 ; p-Nitr o-benzo-nitrile 147. 
 
 o-Nitro-benzoic acid possesses a sweet taste, and dissolves in 164 
 parts of water at 16. Its nitration produces 2, 6-, 2, 5-, 2, 4-dinitro- 
 benzoic acids, and styphnic acid. o-Nitro-benzoyi chloride, m.p. 25, 
 see C. 1901, I. 1227. m-Nitro-benzoic acid dissolves in 425 parts of 
 water (16). Its barium salt dissolves with difficulty. Upon nitration 
 it yields 2, 5-dinitro-benzoic acid. p-Nitro-benzoic acid (chloride, 
 m.p. 75 ; anhydride, m.p. 190 ; see A. 314, 305), called also nitro-dra- 
 crylic acid, because it is formed in the action of nitric acid upon dragon's 
 blood (A. 48, 344), is very sparingly soluble in water. Nitration con- 
 verts it into 2, 4- and 3, 4-dinitro-benzoic acids. The electrolysis of 
 its warm sulphuric acid solution produces p-amido-phenol-sulphonic 
 acid (B. 28, R. 378 ; compare also B. 28, R. 126). 2, 4-, 3, 4-Dinitro- 
 and 2, 4, 6-trinitro-benzoic acids are obtained by the oxidation of the 
 corresponding nitro-toluols. The dinitro-toluols are oxidised by a 
 chromic acid mixture (B. 27, 2209), or by potassium permanganate. 
 Trinitro-toluol is oxidised by a nitric-sulphuric acid mixture at 
 
 I50-220. 
 
 2, 4-Dinitro-benzoic acid melts at 179 ; the 2, 5-acid melts at 177 ; 
 2, 6-acid at 202 ; the 3, 4-acid at 165 ; the 3, 5- or ordinary dinitro- 
 benzoic acid melts at 204. 2, 4, 6-Trinitro-benzoic acid (NO 2 ) 3 
 C 6 H 2 CO 2 H melts at 210 with the elimination of CO 2 (B. 27, 3154 ; 
 28, 2564, 3065, R. 125 ; C. 1899, H- 9 8 )- Chlorimido-m-nitro-benzoic 
 methyl ester NO 2 [3]C 6 H 4 C is formed from benzoyl chloramide 
 
 and diazo-methane ; it occurs in two stereo-isomeric forms, m.p. 
 88 and 84 ; gaseous HC1 reduces both to the same m-nitro-benz- 
 imido-methyl ester NO 2 C 6 H 4 C( : NH)OCH 3 , from which sodium hypo- 
 chlorite restores a mixture of the two isomers (C. 1908, II. 1174). 
 
 Nitro-haloid benzoic acids (C. 1901, II. 287 ; 1902, II. 581). 
 o, o-Fluo-nitro-benzoic acid C 6 H 3 F(NO 2 )COOH, melting at 127, has 
 been prepared by oxidising fluo-nitro-toluol. In contrast with the 
 other o, o-di-substituted benzoic acids, it can be quite readily esterified 
 (B. 29, 842). 1, 4, 6-Mononitro-chloro-benzoie acid, m.p. 165, and 
 two dinitro-chloro-benzoie acids, m.p. 238 and 200, are formed by 
 nitrifying o-chloro-benzoic acid (C. 1900, I. 742). The nitration of 
 m-bromo-benzoic acid yields two o-nitro-acids, both of which yield 
 anthranilic acid upon reduction : 3-bromo-2-nitro-benzoic acid, melting 
 at 250, and 3-bromo-6-nitro-benzoic acid, melting at 139 (compare 
 equivalence of the six hydrogen atoms of benzene). The halogen atom 
 
300 ORGANIC CHEMISTRY 
 
 in the nitro-haloid benzole acids is reactive, like that in the nitro- 
 haloid benzols (B. 22, 3282). 
 
 Nitro-phenyl-aeetie acids NO 2 .C 6 H 4 .CH 2 .CO 2 H are produced by 
 saponifying the nitro-benzyl-cyanides with caustic alkali. The latter 
 bodies constitute the product resulting from the action of potassium 
 cyanide upon the nitro-benzyl chlorides (B. 16, 2064 ; 19, 2635). 
 The nitration of phenyl-acetic acid produces chiefly the p-nitro- 
 body, with little of the o-nitro-acid and o, p-dinitro-phenyl-acetic acid, 
 melting at 166. The latter is also obtainable from 2, 4-dinitro- 
 phenyl-aceto-acetic ester, by saponification with dilute H 2 SO 4 (B. 
 42, 601). 
 
 o-, m-, p-Nitro-phenyl-acetie acid, m.p. 141, 120, 152 
 o-, m-, p-Nitro-benzyl cyanide 84, 61, 116. 
 
 Nitro-hydro-einnamie acids NO 2 C 6 H 4 CH 2 .CH 2 .CO 2 H. p-Nitro- and 
 o-nitro-hydro-cinnamic acids result from the nitration of hydro- 
 cinnamic acid. Both, in turn, yield the o, p-dinitro-acid. The o-nitro- 
 acid is also prepared from o-nitro-p-amido-hydro-cinnamic acid, the 
 first reduction product of the o, p-dinitro-acid, as well as from o-nitro- 
 benzyl-malonic ester (q.v.). The m-nitro-acid is obtained from p-acet- 
 amido-m-nitro-hydro-cinnamic acid (B. 15, 846 ; 29, 635 ; compare 
 also m-nitro-toluol). 
 
 o-, m-, p-Nitro-hydro-einnamie acid, m.p. 115, 118, 163 
 o, p-Dinitro-hydro-einnamie acid, 123 (B. 13, 1680). 
 
 o- and p-Nitro-hydratropic acids NO 2 .C 6 H 4 .CH(CH 3 ).CO 2 H, m.p. 
 no and 87, are produced upon introducing hydratropic acid into 
 strongly cooled fuming nitric acid (A. 227, 262). 
 
 4. Nitroso-monoearboxylie Acids. o-Nitroso-benzoie acid C 6 H 4 [i] 
 NO[2]CO.OH, melting with decomposition at 210. It consists of 
 colourless crystals, green in solution, and is formed from anthranilic 
 acid by oxidation with Caro's acid (B. 36, 3651), and from o-nitro- 
 benzaldehyde by transposition under illumination in indifferent 
 solvents. In alcoholic solutions we obtain the esters : methyl ester, 
 m.p. 153 ; ethyl ester, m.p. 121 (A. 371, 319). o-Nitro-benzylidene- 
 aniline C 6 H 4 [i]NO 2 [2]CH : NC 6 H 5 , in light gives o-nitroso-benz- 
 anfflde C 6 H 4 (NO)CONHC 6 H 5 (B. 35, 2715 ; 36, 4373). In connection 
 with these modes of formation, we have the formation of o-nitroso- 
 benzoic acid by the action of alcoholic ammonia on o-nitro-mandelic 
 nitrile NO 2 [i]C 6 H 4 [2]CH(OH)CN, with elimination of HCN (B. 39, 
 2335). o-Nitroso-benzoic acid is also produced by the oxidation of 
 phenyl-oxy-indol. 4-Nitro- and 2, 4-dinitro-o-nitroso-benzoie acid are 
 transformation products of 2, 4-dinitro- and 2, 4, 6-trinitro-benz- 
 aldehyde in light. 0-, m-, and p-nitroso-benzoic acid, and their esters, 
 are also obtained by the oxidation of the corresponding hydroxyl- 
 amino-benzoic acids, which result from nitro-benzoic acids by reduc- 
 tion (B. 37, 333). 
 
 5. Hydroxylamino - carboxylie Acids. o - Hydroxylamino - benzoic 
 acid C 6 H 4 [2]NHOH[i]COOH, brilliant needles, m.p. 142 with decom- 
 position, obtained by reducing o-nitro-benzoic acid with zinc dust and 
 sal ammoniac. It has the general properties of hydroxylamino-com- 
 pounds : oxidising agents convert it into o-nitroso-benzoic acid, with 
 
AROMATIC AMIDO-MONOCARBOXYLIC ACIDS 301 
 
 which it condenses in alkaline solutions to oo'-azoxy-benzoic acid. On 
 warming with dilute H 2 SO 4 it is partly transposed into 5-oxy-anthra- 
 nilic acid OH[5]C 6 H 3 [2]NH 2 [i]CO 2 H, while the major part passes into 
 its anhydride. 
 
 Benzisoxazolone, oxy-anthr anile 
 
 f[i]CO\ |[i]C(OH) 
 
 ' C H * X 2 NH/ ( U C H 42ft _ 
 
 [ 2 ]N 
 
 m.p. 112 with decomposition. It has an acid character. While 
 the alkali salts, on account of their very difficult breaking up 
 into o-hydroxylamino-benzoic salts, must be regarded as probably 
 derivatives of oxy-anthranile (formula II.), the alkyl- and acyl-benziso- 
 oxazolones obtained from them are reducible to formula I., since, on 
 reduction, they easily form N-alkyl- and acyl-anthranilic acids. 
 
 N-Aeetyl-benzisoxazolone c e H 4{^? COCH x/* . m -P- 118, is also 
 
 formed by condensation of o-nitroso-benzoic acid with paraldehyde 
 under the influence of light (B. 42, 2297). 
 
 6. Aromatic Amido-monoearboxylie Acids. These are obtained by 
 reducing the corresponding nitro-benzoic acids. Like glycocoll, the 
 amido-benzoic acids yield crystalline salts both with acids and bases. 
 They do not combine with acetic acid, hence are precipitated by it 
 from their alkali salts. 
 
 Like glycocoll, these acids can be considered as cyclic ammonium 
 salts (Vol. I.). The hydrogen atoms of the amido-group are replace- 
 able by alkyl and acidyl residues. Dimethylated amido-acids are 
 produced by the action of phosgene and aluminium chloride upon the 
 dimethyl-anilines. Acetamido-benzoic acids are formed by the oxida- 
 tion of the acetyl-toluidins. 
 
 The o-amido-acids (of which o-amido-benzoic acid and o-amido- 
 phenyl-acetic acid are closely related to indigo, and o-amido-hydro- 
 cinnamic acid to quinolin) form hetero-rings, and yield rather remark- 
 able ortho-condensation products. 
 
 Anthranilie acid, o-amido-benzoic acid C,H 4 {^ H or C 6 H 4 \ ' 
 
 ' U2]NH 2 ([2]NH 3 
 
 m.p. 145, sublimates at low pressures without decomposition (C. 
 1903, 1. 922), but breaks down, upon heating, into aniline and carbonic 
 acid. Its aqueous solution has a sweet taste; many of its organic 
 solutions have a blue fluorescence (B. 31, 1693) It was first 
 obtained from indigo (q.v.) by the action of caustic potash (Fritzsche, 
 1841). 
 
 The oxidation can be accelerated by the addition of manganese 
 dioxide (A. 234, 146). The acid results from the reduction of o-nitro- 
 benzoic acid and the two m-bromo-o-nitro-benzoic acids with tin and 
 hydrochloric acid ; from o-nitro-toluol by heating with concentrated 
 potash (C. 1900, I. 1098), and from anthranile, acet-anthranilic acid, 
 and isatoic anhydride by splitting. Cp. o-chloro-benzoic acid. 
 
 Industrially, it is obtained from phthalimide by treatment with 
 bromine and caustic potash (B. 24, R. 966 ; 36, 218 ; /. pr. Ch. 2, 
 80, i) : 
 
 C 6 H 4 (CO) 2 NK+BrOK+2KOH = C 6 H 4 (NH 2 )COOK+BrK-f CO 3 K 2 . 
 
302 ORGANIC CHEMISTRY 
 
 It is also obtained from phthalic hydroxylamine with alkali (C. 1902, 
 II. 1439). 
 
 Nitrous acid converts anthranilic acid, in aqueous solution, into 
 salicylic acid, and sodium, in amyl-alcohol solution, into hexahydro- 
 anthranilic acid, hexahydro-benzoic acid (q.v.), and n-pimelic acid 
 (Vol. I.) (B. 27, 2466). 
 
 With PC1 5 anthranilic acid forms chlorides : COC1.C 6 H 4 NHPOC1 2 , 
 m.p. 62, and (COC1.C 6 H 4 NH) 2 POC1, m.p. I48-I53 (B. 36, 1824). 
 
 The methyl ester, m.p. 25-5, b.p. 125, is a characteristic con- 
 stituent of orange-blossom oil and neroli oil (B. 32, 1512), and is also 
 found in the oil of flowers of Tuber osa (B. 36, 1465). The ethyl ether 
 boils at 260. These esters are also obtained direct from phthalimide, 
 in alcoholic alkaline solution, with alkali hypochlorite (C. 1903, I. 745). 
 Also from isatoic anhydride, with sodium alcoholate and water 
 (B. 33, 28). Its amide, from isatoic acid and ammonia, melts at 108 
 
 (B.18,R.2 73 ). 
 
 Unsym. phenyl-hydrazide, m.p. 134 (A. 301, 89). 
 
 Anthranilic nitrile, o-amido-benzo-nitrile, o-cyananiline NH 2 [2]C 6 H 4 
 CN, m.p. 49, b.p. 267, from nitro-benzo-nitrile, with SnCl 2 and 
 HC1 (B. 42, 3711), or from o-amido-benzaldoxime by splitting 
 off H 2 O (B. 36, 804) ; on heating with Am 2 S it yields the 
 thiamide NH 2 C 6 H 4 CSNH 2 , m.p. 122; with HNO 2 , y-amido-indazol 
 
 C 6 H 4 {^ H ^)N (C. 1903, I. 1270 ; B. 42, 3716). 
 
 Formyl-anthranilic aeid CHO.NH[2]C 6 H 4 [i]CO 2 H, melting at 169, 
 is produced in boiling isatoic acid with formic acid. It condenses on 
 
 heating to keto-dihydro-quinazolone-benzoic acid c.H 4 {^J^ eH4CC 
 
 (B. 35, 3475). 
 
 Aeetyl-anthranilie acid CH 3 CO.NH[2]C 6 H 4 [i]CO 2 H results from 
 anthranilic acid treated with acetic anhydride ; from o.-aceto- 
 toluidin, by oxidation with KMnO 4 , in the presence of magnesium 
 sulphate (B. 36, 1801), and from the oxidation of methyl-ketol and of 
 quinaldin (q.v.). The methyl ester, m.p. 61, and the amide, m.p. 170, 
 have been obtained from anthranilic acid ester and amide. Heating 
 of acetanthranilic acid, or its ester, with POC1 3 produces the so-called 
 dianhydro-diacetanthranilic acid C 18 H 14 N 2 4 , m.p. 250. By heating 
 with acetic anhydride to 150, or, by itself, to 2OO-2io, acetanthra- 
 nilic acid is partly anhydrated to acetanthranile, and partly condensed 
 
 to methyl-dihydro-quinazolone-benzoic acid C 6 H 4 {^^** COOH (B. 
 
 35, 3470). Benzoyl-anthranilie acid C f HCONHC 6 H 4 COOH, m.p. 183, 
 see B. 26, 1304 ; A. 324, 134. Benzo-sulphone-anthranilic aeid, 
 C 6 H 5 SO 2 NHC 6 H 4 COOH, m.p. 214 ; chloride, m.p. 155 (A. 367, 104). 
 
 rCH. 
 Anthranile c 6 H 4 j | No, b.p. 18 99 (B. 42, 1647), an oil of a 
 
 peculiar odour, volatile in water vapour. It is dealt with in this place 
 because it behaves, in many reactions, like an anhydride of anthranilic 
 
 (CO 
 acid, C 6 H 4 s I fi-lactame, being transformed by alkalies into 
 
 INK 
 
 anthranilic acid, and by acetic anhydride into acetanthranile. These 
 reactions, however, probably take place with an intramolecular atomic 
 
AROMATIC AMIDO-MONOCARBOXYLIC ACIDS 303 
 
 displacement. A direct conversion of anthranilic acid into anthranile 
 has not been hitherto accomplished. The modes of formation of 
 anthranile are as follows : (i) from nitro-benzaldehyde by reduction 
 with tin and acetic acid, or with ferrous sulphate and ammonia ; (2) 
 from acido-benzaldehyde ; (3) from o-nitroso-benzyl alcohol, on boiling 
 with water ; (4) from amido-benzaldehyde by oxidation with Caro's acid. 
 These reactions lead to the conclusion that anthranile is an anhydride 
 or inner ether of the unstable o-hydroxylamino-benzaldehyde 
 
 C 6 H 4 <( (see B. 36, 3653), whose oxime is obtained by treating 
 
 v. JN rKJjj 
 
 it with hydroxylamine, and whose nitroso-compound results from the 
 action of HNO 2 . This view is supported by the easy reduction of 
 anthranile to o-amido-benzaldehyde, and the close relation to anthrox- 
 
 i C COOH 
 anic acid C a H 4 - | ^ Q (<?*>) > apparent from the analogous forma- 
 
 tion and especially from the fact of its passing into anthranile on 
 heating with water to 150 (/. pr. Ch. 2, 81, 254). The improbability 
 of the /Mactame formula is also seen by a comparison with dianthra- 
 nilide, which must be taken as a true molecular anhydride of anthranilic 
 acid. Anthranile is easily obtained from the dimercury compound of 
 o-nitro-toluol by the action of concentrated HC1. With corrosive 
 sublimate, anthranile forms a characteristic double compound C 7 H 5 NO. 
 HgCl 2 , m.p. 178. With chlorine, it combines to form a dichloride 
 
 C 6 H 4 { | \o m.p. 77, which, on heating with water, passes into 
 
 (NCI/ 
 
 B 2 -monochlor-anthranile, m.p. 79, with migration of a chlorine atom 
 B. 42, 1701). 
 
 Methyl-anthranile C 6 H 4 CH ^>O, from o-nitro-aceto-phenone, 
 
 and phenyl-anthranile C 6 H 4 C6H5 O, from o-nitro- or o-amido- 
 
 benzo-phenone, must be regarded as true homologues of anthranile 
 (B. 36, 819, 2042). Anthranile derivatives are probably traceable 
 in the compounds produced by the condensation of o-nitro-benzalde- 
 hyde with phenols and tertiary amines in the presence of concentrated 
 HC1 (B. 42, 1714). 
 
 Acetyl-anthranile C 6 H 4 {^1 CH3 or c 6 H 4 {^ OCHg , m.p. 8i,b.p. 14 
 
 147, from anthranile or acetanthranilic acid, as well as carbox-ethyl- 
 anthranilic acid, with acetic anhydride. It must therefore be regarded 
 as a true anhydride of acetanthranilic acid. With NH 3 it yields 
 o-acetamido-benzamide ; with aniline and other amine bases it gives 
 
 derivatives of methyl - dihydro - quinazolone C 6 H 4 j A 
 
 ' 
 
 similar behaviour is shown by benzoyl-anthranile CJi< or 
 
 WJN =L/L>j-rijj 
 
 C 6 H 4 -[ < ?? r , r , , m.p. 122, formed from benzoyl-anthranilic acid by 
 
 Vi .W Ov_/V-xg JuLc 
 
 splitting off H 2 O ; from anthranilic acid, benzoyl chloride, and pyridin 
 in the cold ; and from anthranile after several hours' heating with 
 benzoyl chloride (B. 35, 3480 ; 36, 2766). The very smooth formation 
 of acidyl-anthraniles from the acidyl-anthranilic acids, as well as the 
 
304 ORGANIC CHEMISTRY 
 
 close relations to the quinazolones, indicate the first formula rather 
 than the second. This is corroborated by the anhydride formation 
 of those acyl-anthranilic acids, like benzol-sulphone-anthranilic acid 
 and picryl-anthranilic acid, in which the formation of compounds of 
 
 (CO.O 
 the formula C 6 H 4 1 I * s difficult, or is impossible, dimolecular 
 
 anhydrides being formed (see Dianthranilides, and A. 367, 124). The 
 acyl-anthraniles must therefore be regarded as j3, y-benzo-metoxazins, 
 and are closely related to the anhydrides obtained from benzoyl-a- 
 amido-acids ; cp. hippuric acid, benzoyl-alalin, etc. 
 
 DIMOLECULAR ANHYDRIDES OF ANTHRANILIC ACID (A. 367, 101). 
 While, therefore, anthranile cannot be regarded as a simple anhy- 
 dride of anthranilic acid, dimolecular true anhydrides of anthranilic 
 acid are known : anthranoyl-anthranilic acid, anthranoyl-anthranilic 
 anhydride (anthranoyl-anthranile), and dianthranilide, which can all 
 be broken up to obtain anthranilic acid. 
 
 Anthranoyl-anthranilic aeid NH 2 [2]C 6 H 4 [i]COHN[2]C 6 H 4 [i]COOH, 
 m.p. 203, is formed (i) by reduction of o-nitro-benzoyl-anthranilic 
 acid ; (2) by condensation of anthranilic acid with isatoic anhydride ; 
 and hence (3) as an intermediate product in the industrial preparation 
 of anthranilic acid from phthalimide, sodium hypochlorite, and sodium 
 hydrate (/. pr. Ch. 2, 80, i). On heating above the melting-point, 
 or, more easily, by the action of thionyl chloride, it liberates water and 
 passes into anthranoyl-anthranilic-acid-0-anhydride, anthranoyl-anthra- 
 
 nile C 6 H 4 {^ C H NH , ni.p. 162, yellow needles, easily polymerised 
 on heating. Its benzol-sulphone compound C 6 H 4 /^ T ' 
 
 tJN =U.Ugil 4 JNxl.olJ2v>e-cl5, 
 
 m.p. 223, is formed by the action of benzol-sulpho-chloride upon 
 anthranile (B. 40, 997). By repeatedly treating anthranoyl-anthranilic 
 acid with nitro-benzoyl chloride, and then reducing, anhydrides of 
 anthranilic acid are obtained, which have a polypeptide character, e.g. 
 NH 2 C 6 H 4 CO.NHC 6 H 4 CO.NHC 6 H 4 COOH, etc. (A. 351, 267). 
 
 Dianthranilide c 6 H 4 {^ ] ] ^^^}c 6 H 4 , m.p. about 330, colourless 
 
 needles, is obtained from its monoacetyl compound, the product of 
 the action of concentrated H 2 S0 4 and glacial acetic acid upon dibenzol- 
 sulphone-dianthranilide, on boiling with NaHO. It has the character 
 of a weak dibasic acid, and yields a disodium salt, which, on methylation 
 with dimethyl sulphate, passes into N, N-dimethyl-dianthranilide 
 
 N(CH 3 ).CO 
 
 Boiling with concentrated alkali breaks up the dianthranilide into 
 two molecules of anthranilic acid. 
 
 Dibenzol-sulphone- dianthranilide c 6 H 4 c 6 H 4 , m.p. 
 
 264, is formed by heating benzol-sulpho-anthranilic chloride with 
 pyridin. 
 
 Carboxyl-anthranilie dimethyl ester and diethyl ester, isatoic dialkyl 
 ester C 6 H 4 (NHCOOCH 3 )COOCH 3 , m.p. 61, b.p. 12 166, and m.p. 44, 
 b.p. 10 174, are obtained from phthalimide chloride, or bromide, 
 C 6 H 4 (CO) 2 BrN, by the action of sodium alcoholates ; further action 
 converts them into the acid isatoic esters : earboxy-methyl and carboxy- 
 
AROMATIC AMIDO-MONOCARBOXYLIC ACIDS 305 
 
 ethyl-anthranilic acid C 6 H 4 (NHCO 2 C 2 H 5 )COOH, m.p. 181 and 126, 
 also obtained from anthranilic acid with chloroformic esters, and from 
 isatoic anhydride by heating with alcohols. Treatment with acetyl 
 
 fCO.O 
 chloride converts them into isatoic anhydride C 6 Hj I , m.p. 
 
 HNH.CO 
 
 233-240. It was first obtained by oxidising a glacial acetic acid 
 solution of indigo with chromic acid (H. Kolbe, 1885), and, later, from 
 anthranile and anthranilic acid by the action of chloro-carbonic esters 
 (B. 22, 1672). Also by conducting phosgene into sodium-anthranilate 
 solution. 
 
 It is very sparingly soluble in water. Digested with alkalies or 
 
 alkaline earths, it forms unstable salts of the formula Ct 
 
 from which CO 2 regenerates isatoic anhydride. With excess of alkali, 
 salts of isatoic acid are first formed, and these, digested with alkalies, 
 or, instantly, on adding acids and CO 2 , are broken up into CO 2 and 
 anthranilic acid ; free isatoic acid can therefore not be obtained (B. 32, 
 2159 ; 33, 21 ; /. pr. Ch. 2, 79, 281). Ammonia, hydrazin, phenyl- 
 hydrazin, and hydroxylamine change it into the corresponding amide 
 derivatives of anthranilic acid (B. 19, R. 65 ; 26, R. 585). 
 
 Isatoic anhydride forms an important intermediate product in the 
 industrial preparation of anthranilic acid from phthalimide, sodium 
 hypochlorite, and NaHO, and can be isolated if an excess of NaHO is 
 avoided. The processes involved are represented by the following 
 system of formulae (/. pr. Ch. 2, 80, i) : 
 
 r /COONa ClONa r w f /% -NaCl 
 
 C *McONH 2 l 
 
 r fCO. 
 C H *\N= 
 
 CO.O NaOH f COONa _.co t> r COONa 
 
 CONa " C H *\NHCOONa~ 
 
 Kynuric acid, oxalyl-anthranilic acid, carbostyrilic acid CO 2 H. 
 CONH[2]C 6 H 4 [i]CO 2 H-j-H 2 O, becomes anhydrous at 100, and melts 
 at 180 with decomposition. It is formed from the quinolin deriva- 
 tives kynurin (q.v.), kynurenic acid (q.v.), a-phenyl-quinolin (q.v.), 
 carbostyrile (q.v.), aceto-tetrahydro-quinolin, and indoxylic acid (q.v.) 
 by oxidation. It is prepared synthetically by heating anthranilic acid 
 with oxalic acid to 130 (B. 17, 401 ; R. no). Its monoethyl ester CO 2 . 
 C 2 H 5 CO.NH[2]C 6 H 4 [i]CO 2 H is formed in the oxidation of the ester of 
 indoxylic acid (B. 15, 778). It melts at 180. 
 
 Oxalyl-anthranilic acid nitrile, o-cyano-anilic acid CO 2 H.CONH 
 [2]C 6 H 4 [i]CN, m.p. 126. The methyl" ester, m.p. 139, has been ob- 
 tained by condensing o-amido-benzo-nitrile with oxalic ester. Dilute 
 acids transpose the nitrile into the isomeric 4-keto-dihydro-quinazolin- 
 
 /CO.NH 
 
 2-carboxylic acid C 6 H 4 < I (B. 42, 3710). 
 
 X N=CCOOH v 
 
 Dicyanamino - benzoyl C 6 H 4 {^ I]CO> ^ (Anschiitz) melts with 
 
 U [2jN =C.CN 
 
 decomposition. It results from cyanogen and o - amido - benzoic 
 acid in aqueous solution (B. 11, 1086). Ethoxy-cyanamino-benzoyl 
 
 f[i]CO.N 
 
 C 6 H 4 -! melting at 173, is formed from cyanogen and 
 
 i[2]NH.C.OC 2 H 6 
 
 VOL. II. X 
 
306 ORGANIC CHEMISTRY 
 
 anthranilic acid in alcoholic solution (B. 11, 1986). Ammonia changes 
 
 ( [i]CO.N 
 it to o-benzo-glyco-eyamidin, benzoylene-guanidin C 6 HJ y 
 
 [ [2JNH.C : NH 2 
 which CH 3 I, in strong alkaline solution, converts into a-o-benzo- 
 
 r[i]co N 
 
 creatinin C 6 HJ || (B. 13, 977). 
 
 1[2]N(CH 3 ) C:NH 2 V 
 
 Methyl-anthranilic acid CH 3 NH[2]C 6 H 4 [i]COOH, m.p. 182, from 
 anthranilic acid with soda and methyl iodide or dimethyl sulphate in 
 methyl alcoholic, or aqueous, solution ; also from o-chloro-benzoic acid 
 with methyl-amine and copper (C. 1903, II. 1099). Methyl ester CH 3 
 NHC 6 H 4 COOCH 3 , b.p. 13 129 (C. 1902, II. 1257). The aci d is converted 
 into indoxyl (and indigo) by heating with NH 2 Na, alkali, or amalgams 
 of alkaline earth metals ; this conversion is even more direct in the 
 case of the acyl-methyl-anthranilic acids : formyl-methyl-anthranilie 
 acid CHON(CH 3 )C 6 H 4 COOH, m.p. 169, and formyl-ethyl-anthra- 
 nilic acid, m.p. 119, obtained from methyl- and ethyl-quinolinium salts 
 by oxidation with permanganates (B. 36, 1806 ; C. 1903, I. 745). 
 
 Nitroso-methyl-anthranilic acid NO.N(CH 3 )C 6 H 4 COOH, m.p. 127, 
 from methyl-anthranilic acid with HNO 2 or oxidation of nitroso- 
 methyl-o-toluidin with MnO 4 K (B. 34, 1644). Hydrochloric acid 
 transposes it into 5-nitroso-methyl-anthranilic acid NO[5]C 6 H 3 [2] 
 NHCH 3 [i]COOH, which, on boiling with soda solution, splits off methyl- 
 amine, and passes into 5-nitroso-salicylic acid (B. 42, 2745). On fur- 
 ther methylation, methyl-anthranilic acid passes into dimethyl-anthra- 
 nilic acid (CH 3 ) 2 N[2]C 6 H 4 [i]COOH, m.p. 70, from which anthranilic 
 
 betain, o-benzo-beta'in C 6 H 4 /^ CH 3)3\O, m.p. 227, is generated. The 
 
 t UL) / 
 
 latter, on heating to 240, transposes into dimethyl-anthranilic methyl 
 ester, b.p. 1]L 131 (B. 37, 411 ; cp. m- and p-amido-benzoic acid, and 
 anilido-acetic acid ; also Betain, Vol. I.). 
 
 Ethyl-anthranilic acid, m.p. 153, see B. 39, 3236. Diethyl-an- 
 thranilic acid, m.p. 121, M. 25, 487. 
 
 Aryl-anthranilic acids are formed by heating o-chloro-benzoic acid 
 with aromatic amines, in the presence of copper (A. 355, 312). On 
 heating alone, they split off CO 2 , and pass into diphenyl-amines ; and 
 on heating with concentrated SO 4 H 2 , into acridone. Phenyl-anthranilic 
 acid C 6 H 5 NHC 6 H 4 COOH, m.p. 181, is also obtained by de-amidating 
 amido-phenyl-anthranilic acid. Diphenyl-anthranilic acid (C 6 H 5 ) 2 
 NC 6 H 4 COOH, m.p. 208, from phenyl-anthranilic acid, iodo-benzol, 
 and copper. On heating, it decomposes into CO 2 and triphenyl-amine 
 (B. 40, 2448). Picryl-anthranilic acid (NO 3 ) 3 C 6 H 2 NHC 6 H 4 COOH, 
 m.p. 272 (A. 367, 118). Diphenyl-amine-o, o'-, -o, m'- and o, p'-diearb- 
 oxylic acid CO 2 HC 6 H 4 NHC 6 H 4 CO 2 H, m.p. 295, 296, and 290 with 
 decomposition, from o-chloro-benzoic acid with o-, m-, and p-amido- 
 benzoic acid (A. 355, 352). Sym. diphenyl-p-phenylene-diamine-o, o'- 
 dicarboxylic acid CO 2 H[i]C 6 H 4 [ 2 ]NH[i]C 6 H 4 [4]NH[2]C 6 H 4 [i]CO 2 H, 
 m.p. 288 with decomposition, from p-dibromo-benzol, anthranilic acid, 
 and copper (C. 1906, II. 932). 
 
 Formaldehyde condenses with anthranilic acid in various molecular 
 ratios, according to the conditions. 
 
 Methylene-dianthranilie acid, formaldehyde-dianthranilic acid CH 2 
 
AROMATIC AMIDO-MONOCARBOXYLIC ACIDS 307 
 
 (NH[2]C 6 H 4 COOH) 2 , m.p. 158 with decomposition, from 2 molecules 
 anthranilic acid and I molecule formaldehyde solution, is transposed by 
 methyl-alcoholic HC1 into p 2 -diamido-diphenyl-methane-diearboxylie 
 acid CH 2 [C 6 H 3 (NH 2 )COOH] 2 ; by acetylation with acetic anhydride 
 and sodium acetate, we obtain methylehe-diaeeto-anthranilie acid CH 2 
 [N(COCH 3 )C 6 H 4 COOH] 2 . Potassium cyanide splits up formaldehyde- 
 dianthranilic acid into anthranilic acid and anthranilido-aceto-nitrile 
 (A. 324, 1 1 8). By the condensation of equimolecular quantities of for- 
 maldehyde and anthranilic acid, and its N-mono-substitution products 
 (CO 2 HC 6 H 4 NHR), we obtain compounds insoluble in alkalies, the so- 
 called formalities, which may be used for characterising, and isolating, 
 substituted anthranilic acids, since they are easily dissolved into their 
 components on heating with acids or alkalies. Anthranilic formalide 
 
 , m.p. i45-i48 with decomposition ; phenyl-anthranilic 
 
 By treating with KCN or alkaline bisulphite, the formalides 
 are split up, with formation of salts of cu-cyano-methyl-anthranilic 
 
 acids c H 4< l2CN ' and w " sul P ho " m ethyl - anthranilic acids 
 
 With excess Qf formaldehyde> anthranilic acid 
 
 combines, on heating, to form anthranilic diformalide ; it forms a 
 heavy yellow oil insoluble in alkali, combining with I molecule KCN 
 to a mononitrile C 8 H 4 <f NjjCH,.CN) .CH 2 ^ m ^ and with 2 mo i ecu i es 
 
 \O(_) - O 
 
 KCN to anthranilido-diaceto-nitrile C 6 H 4<(^^ CN)2 , m.p. i68-i7i 
 
 with decomposition (B. 42, 3534; C. 1910, 1. 309). Methylene-anthra- 
 nilic acid CO 2 HC 6 H 4 N : CH 2 , m.p. about 210 (B. 41, 1565). 
 
 Anthranilido-acetic acid, phenyl-glycin-o-carboxylic acid COOH[2] 
 C 6 H 4 NHCH 2 COOH, m.p. 215 with decomposition, has acquired great 
 technical importance on account of its transformation into indoxyl 
 and indigo. It is formed : (i) from chloracetic acid and anthra- 
 nilic acid, in neutral solution ; with excess of chloracetic acid we obtain 
 anthranilido-diacetic acid COOHC 6 H 4 N(CH 2 COOH) 2 , m.p. 212 with 
 decomposition (B. 33, 3182) ; (2) from anthranilic acid on heating 
 with multivalent alcohols, like glycerine, mannite, etc. (C. 1900, II. 
 549) ; (3) by saponification of anthranilido-aceto-nitrile COOH[2]C 6 H 4 
 NHCH 2 CN, m.p. 181 with decomposition, which is obtained from 
 anthranilic acid, formaldehyde, and KCN, or by splitting up formalde- 
 hyde-dianthranilic acid, or anthranilic formalide with KCN (A. 324, 
 118 ; /. pr. Ch. 2, 63, 392 ; B. 39, 989) ; (4) from o-chloro-benzoic 
 acid, by heating with glycocoll in the presence of alkaline carbonate 
 and copper (C. 1903, II. 81, 610). On heating with caustic alkalies, or 
 acetic anhydride and sodium acetate, the acid passes into indoxyl and 
 its derivatives, which are easily converted into indigo : 
 
 /NHCH,CO,H _ /NH 
 
 \ COOH -* 2C ' H M 
 
 The esters : dimethyl ester, m.p. 97 ; diethyl ester, m.p. 75, are 
 condensed by means of sodium ethylate to indoxylic acid esters. The 
 
5 o8 ORGANIC CHEMISTRY 
 
 condensation of anthranilido-acetic acid, and its esters, is facilitated by 
 introducing acyl, or alkyl, groups into N-position. 
 
 Aeetanthranilido-aeetic acid COOHC 6 H 4 N(COCH 3 )CH 2 COOH, m.p. 
 214 with decomposition ; diethyl ester, m.p. 64. Methyl-anthranilido- 
 acetie acid COOHC 6 H 4 N(CH 3 )CH 2 COOH, m.p. 189 with decomposi- 
 tion (B. 35, 1683 ; C. 1903, I. 305). Phenyl-anthranilido-acetic acid 
 COOHC 6 H 4 N(C6H 5 )CH 2 COOH, m.p. 166 ; its nitrile is formed from 
 phenyl-anthranilic formalide with KCN (C. 1910, I. 309). 
 
 p-Sulpho-anthranilic acid SO 8 H[4]NH 2 [2]C e H 8 COOH is formed 
 from o-nitro-toluol-sulphonic acid with NaHO, in a manner analogous 
 to the formation of anthranilic acid from o-nitro-toluol (C. 1903, 1. 371). 
 
 3, 5-Dibromo-anthranilic acid from o-nitro-toluol with bromine (M. 
 28, 987) . Of the six possible isomeric diehloro-anthranilie acids, five are 
 known ( B. 42, 3533 ; C. 1910, 1. 310). Tetraehloro-anthranilic acid C1 4 C 6 
 [2]NH 2 [i]CO 2 H, m.p. 182, from tetrachloro-phthalic anhydride (B. 42, 
 3549). 5-Nitro-anthranilic acid NO 2 [5]NH 2 [2]C 6 H 3 CO 2 H, m.p. 269, is 
 obtained from its aceto-compound, m.p. 221, which results from the 
 oxidation of nitro-aceto-toluide with (MnO 4 )Ca (B. 36, 1801) ; besides 
 the isomeric acid NO 2 [4]NH 2 [2]C 6 H 3 CO 2 H, it is formed from 4-nitro- 
 phthalimide with KOBr (C. 1902, II. 359). In the same way, 3- and 
 6-nitro-anthranilic acids, m.p. 203 and 180 with decomposition, are 
 formed from 3-hitro-phthalimide with KOBr. Dinitro-anthranilic 
 acid (NO 2 ) 2 [3, 5]NH 2 [2]C 6 H 2 COOH, m.p. 265, from dinitro-chloro- 
 benzoic acid with NH 3 (C. 1901, II. 545). 
 
 Hetero-ring Formations of Anthranilic Acid and its Derivatives. 
 It is evident from the formation of acidyl anthraniles, isatoic anhydride, 
 indoxyl, and other substances mentioned above, that anthranilic acid 
 and its derivatives are very prone to the formation of heterocyclic 
 ring systems, and " ortho-condensation." (Compare o-amido-benzyl 
 alcohol, o-amido-benzaldehyde, and o-amido-aceto-phenone.) 
 
 Acetyl-anthranilic acid and phenol condense, on heating, to acri- 
 done, which also results in digesting phenyl-anthranilic acid with con- 
 centrated sulphuric acid (B. 25, 2740). Anthranilic acid condenses 
 with aceto-phenone and aceto-acetic ester to quinolin derivatives 
 (B. 27, 1396) : 
 
 H 2 
 
 ]COOH ' CH 2 .C0 2 C 2 H 5 
 
 + 
 
 Co.CH 3 
 
 [i]COOH CH 3 -2H 2 /C(OH) =CH a-Phenyl-y-oxy- 
 
 O]NH 2 + CO.C 6 H 6 4 \N=C.C 6 H 5 quinolin. 
 
 o-Benzoylene-urea is formed on heating anthranilic acid and anthra- 
 nil-amide with urea. It also results upon heating carboxethyl-o- 
 amido-benzamide (B. 2, 416 ; 22, R. 196), as well as by the action of 
 mineral acids upon uramido-benzoic acid (B. 27, 976). Keto-dihydro- 
 quinazolins are produced on heating formyl-, acetyl-, and benzoyl-o- 
 amido-benzamide. The jS-methyl compound is formed in the action 
 of acetamide upon anthranilic acid, and ammonia upon ethyl-acet- 
 amido-benzoic ester (B. 20, R. 630 ; 22, R. 196 ; 27, R. 516 ; C. 1903, 
 I. 174, 1270). a-Phenyl-j3-keto-dihydro-quinazolin results from heat- 
 ing anthranilic-acid ester with benzimido-ethyl ester (C. 1906, II. 1124). 
 
AROMATIC AMIDO-MONOCARBOXYLIC ACIDS 309 
 
 The condensation products of o-amido-benzoic acid and cyanogen gas 
 have been described and formulated : 
 
 C a H 4 { 
 
 [i]COOH 
 
 _[2]NH.CO.NH 2 \ c H /CO NHo-Benzoylene-urea 
 
 H f[i]CONH 2 0,11.0)"*' 6 4 \NH CODiketo-tetrahydro-quinazolin 
 
 6 4 1[2]NH.COOC 2 H S ~ 
 
 TT /[i]C0 2 C 2 H 5 NH\ r r - 2 c,Ho r /CO.N a-Phenyl-tf-keto- 
 
 C6l H[2]NH 2 +C 2 H 5 0/ 6 4 lNH.CC 8 H 6 dihydro-quinazolin. 
 
 Nitrous acid converts anthranil-amide directly into benzazimide, 
 whereas the o-diazo-benzoic ester first resulting from anthranilic ester 
 must be treated with ammonia to effect this change. Similarly, an- 
 thranilic thio-amide gives rise to thio-benzazimide (B. 42, 3719). 
 
 o-Diazo-amido-benzol-carboxylie ester, m.p. 76, on boiling with 
 alcohol, gives a-phenyl-pheno-J3-triazone or benzazanile (B. 21, 1538, 
 R. 57i ; / pr- Ch. 2, 64, 70) : 
 
 m- and p-Amido-benzoic acid melt at 173 and 186 respectively. 
 Their aceto-compounds, melting at 250 and 256, result when m- and 
 p-aceto-toluide are oxidised by permanganates (B. 36, 1801) ; p-amino- 
 benzo-nitrile, m.p. 86 (see C. 1903, II. 113). m-Amino-benzo-nitrile, 
 m.p. 53 (see C. 1904, II. 100). m- and p-Methyl-amido-benzoie acid 
 CH 3 NHC 6 H 4 CO 2 H, m.p. 127 and 161, are produced by methylating 
 the amido-acids with dimethyl sulphate (B. 43, 210 ; 42, 3744)'. The 
 p-methyl-amido-benzoic acid is obtained, by nuclear synthesis, from 
 the magnesium-iodide compound of methyl-aniline C 6 H 5 N(CH 3 )MgI, 
 by the action of CO 2 and transposition of the first product, a carbamin- 
 ate C 6 H 5 N(CH 3 )COOMgI, by heating, in a process akin to the synthesis 
 of salicylic acid. From N-methyl- and ethyl-o-toluidin, in a similar 
 manner, p-methyl-amido- and p-ethyl-amido-m-methyl-benzoie acids 
 are generated, melting at 201 and 170 respectively. Dimethyl- 
 aniline and diethyl-aniline react similarly with CH 3 MgI and CO 2 , 
 forming p-dimethyl- and p-diethyl-amido-benzoic acid, m.p. 236 and 
 193 (B. 42, 4488, 4815). 
 
 By methylation with ICH 3 and KOH, m- and p-amido-benzoic 
 acids, like anthranilic acid, yield compounds resembling betain 
 
 C 6 H 4 /^^ :H3 ^ 3 No, which, on heating, isomerise to m- and p-dimethyl- 
 
 amido-benzoic ester (B. 37, 414). p-Amido-benzoic-diethyl-amino- 
 ethyl ester NH 2 [4]C 6 H 4 [i]COOCH 2 CH 2 N(C 2 H 5 ) 2 -f-2H 2 O, m.p. 51, 
 melting at 61 when anhydrous, results from the interaction of 
 p - nitro-benzoyl chloride and ethylene chloro-hydrin, followed by 
 reduction and transformation with diethyl-amine. Its monochloro- 
 hydrate, m.p. 156, is used as a local anaesthetic under the name of 
 Novocain (A. 371, 125). 
 
 Chrysanisic acid, 3, 5-dinitro-4-amido-benzoie acid 
 
3io ORGANIC CHEMISTRY 
 
 C 6 H 2 CO 2 H, melting at 259, consists of golden-yellow flakes, and is 
 produced when 3, 5-dinitro-4-methoxy-benzoic acid is heated with 
 aqueous ammonia. 
 
 Diamido-benzoic acids (NH 2 ) 2 C 6 H 3 CO 2 H are prepared by reducing 
 the dinitro- and the nitro-amido-benzoic acids. 2, 4-Diamido-benzoie 
 acid (NH 2 ) 2 [2, 4]C 6 H 3 COOH is obtained from its diaceto-compound 
 (B. 36, 1803). The acids break down in dry distillation into carbon 
 dioxide and phenylene-diamines. Like the o-phenylene-diamines, the 
 diamido-benzoic acids, containing two amido-groups in the ortho- 
 position with reference to each other, readily yield heterocyclic deriva- 
 tives e.g. nitrous acid converts 3, 4-diamido-benzoic acid into 3, 4- 
 azimido-benzoic acid (B. 15, 1880). Them, p- and the p, m-amido-ur- 
 amido-benzoic acids yield two different uramido-azimido-benzoic acids, 
 which afford the same azimido-benzoic acid by saponification (B. 29, 
 R. 586). The 2, 3-diamido-benzoic acid forms characteristic com- 
 pounds, with many varieties of sugar. 
 
 3, 4, 5-Triamido-benzoie acid (NH 2 ) 3 .C 6 H 2 .CO 2 H, from chrysanisic 
 acid by reduction, breaks down, when heated, into CO 2 and i, 2, 3-tri- 
 amido-benzol (A. 163, 12). 2, 3, 5-Triamido-benzoic acid (B. 15, 2199), 
 from dinitro-anthranilic acid (C. 1902, II. 1293). 
 
 Many amido-acids, derived from alkyl-benzoic acids, are known ; 
 also haloid amido-acids, nitro-amido-acids, etc. 
 
 Amido-phenyl-fatty acids are obtained from the nitro-phenyl-fatty 
 acids. Certain o-amido-phenyl-fatty acids are particularly note- 
 worthy because of their tendency to form inner anhydrides : y- or 8- 
 lactames (I. 359), which is so great that the corresponding free o-amido- 
 acids are not capable of existing e.g. o-amido-phenyl-acetic acid and 
 o-amido-phenyl-hydro-cinnamic acid. 
 
 m- and p-Amido-phenyl-acetic acids melt at 149 and 200. 
 
 m- and p-Amido-hydro-cinnamic acids ,, 84 ,, 131. 
 
 4- Amido-^-nitro-hydro-cinnamic acid, from p-acetamido-hydro- 
 cinnamic acid, melts at 145. 
 
 p- Amido-hydratropic acid, melting at 128. 
 
 y- and S-Lactames of the o-Amido-phenyl-fatty Acids. Oxindol, 
 
 the lactame of o-amido-phenyl-acetic acid, c H 4/r ' ' me lting at 
 
 120, is obtained by the reduction of o-nitro-phenyl-acetic acid with 
 tin and hydrochloric acid, and from dioxindol with sodium amalgam. 
 If heated to 150 with baryta water it is converted into the 
 barium salt of o-amido-phenyl-acetic acid, from which oxindol is 
 separated by acids (B. 16, 1704). Nitrous acid converts it into isat- 
 oxime (q.v.). 
 
 Oxindol boiled with acetic anhydride yields aceto-oxindol, 
 
 - 00 ' melting at 126. It dissolves to aceto-o-amido- 
 
 phenyl-acetie acid 3 CH 3 .CO.NH.C 6 H 4 .CH 2 .CO 2 H, melting at 142. 
 Heated with alkalies or acids it breaks down into oxindol and acetic acid. 
 p-Amido-oxindol NH 2 .C 8 H 6 NO, melting about 200, is formed by 
 the reduction of 2, 4-dinitro-phenyl-acetic acid with tin and hydro- 
 chloric acid. If ammonium sulphide be used as the reducing agent, 
 the product will be ^-amido-2-nitro-phenyl-acetic acid, melting at 185 
 (B. 14, 824) ; compare o-nitro-phenyl-iso-nitroso-acetic acid. 
 
 6 H 4 / 
 
DIAZO-BENZOIC ACIDS 311 
 
 Atroxindol, lactame of o-amido-hydratropic acid, 
 
 melts at 119. 
 
 Hydrocarbo-styrile, lactame of amido-hydro-cinnamic acid, melting at 
 163, is formed by the reduction of o-nitro-hydro-cinnamic acid with tin 
 and hydrochloric acid (Glaser and Buchanan, 1869) (B. 15, 2103) ; by 
 heating hydrocarbo-styrile-carboxylic acid, resulting from the reduction 
 of o-nitro-benzyl-malonic acid (B. 29, 667) ; and from hydrindone 
 oxime by Beckmann's transposition (B. 29, 667). 
 
 Hydrocarbo-styrile has the same relation to quinolin that oxindol 
 bears to indol : 
 
 o a Hydrocarbo-styrile C.H 4 Quinolin. 
 
 p-Amido-hydroearbo-styrile NH 2 C 9 H 8 NO, m.p. 211, is formed, 
 together with 4-amido-2-nitro-hydro-cinnamic acid, melting at 139, 
 from 2, 4-dinitro-hydro-cinnamic acid. 
 
 7. Diazo-benzoic Acids are produced from the mineral acid salts of 
 the amido-benzoic acids with nitrous acid, just as the ordinary diazo- 
 bodies are obtained from the aniline salts. Nitrous acid converts the 
 amide of o-amido-benzoic acid into benzazimide. The free diazo- 
 benzoic acids are very unstable. The diazide of anthranilic acid 
 
 C 6 H 4/^^ DS )>O consists of white, glistening needles. It is obtained 
 
 L[2]N 2 / 
 
 when the chloride is acted upon with silver oxide (B. 29, 1535). 
 
 8. Diazo-amido-benzoic Acids are formed when nitrous acid is 
 conducted into the alcoholic solution of the amido-benzoic acids. 
 Diazo-m-amido-benzoic acid CO 2 H[i]C 6 H 4 [3]N=N-NH[3']C6H 4 [i'] 
 CO 2 H is an orange-red powder. Hydrofluoric acid converts it into 
 m-fluoro-benzoic acid. 
 
 N \ 
 
 9. Diazo - imido - benzoie Acids || )>N.c 6 H 4 co 2 H result when 
 
 w 
 
 ammonia acts upon the perbromides of diazo-benzoic acids, or when 
 hydrazin-benzoic acids are treated with nitrous acid. The o-body 
 melts at about 70 ; the meta- at 160 ; and the p-compound at 185 
 (B. 9, 1658). 
 
 /N.C 6 H 4 CO 2 H 
 
 10. Azoxy-benzoic Acids o< | are formed in the reduction 
 
 X N.C 6 H 4 CO 2 H 
 
 of the nitro-benzoic acids with alcoholic potash. The o-derivative is 
 also produced when n-oxy-indol-carboxylic acid (q.v.) is oxidised with 
 alkaline potassium permanganate (B. 17, 1904 ; 24, R. 666; 29, 656). 
 
 N.C 6 H 4 .CO 2 H 
 
 11. Azo-benzoic Acids | ' . These result from the action 
 
 N.C 6 H 4 .CO 2 H 
 
 of sodium amalgam upon the nitro-benzoic acids ; or from the action 
 of zinc dust and NaHO in alcoholic solution upon the same ; or from 
 the action of highly concentrated NaHO upon nitro-benzaldehydes 
 (B. 34, 4132 ; C. 1904, 1. 722). o-, m-, and p-Azo-benzoic acid decom- 
 pose on melting. By the distillation of the calcium salts, azo-phenylene, 
 or phenazin, is formed. 
 
 Azo-benzol-o-monocarboxylic acid C 6 H 5 N 2 [i]C 6 H 4 [2]COOH, m.p. 
 92, and its homologues, result from the condensation of o-nitro- 
 benzoic acid with primary anilines (C. 1909, I. 69). PC1 5 converts 
 
312 ORGANIC CHEMISTRY 
 
 them into y-oxy-fi-phenyl-indazols (q.v.) (C. 1907, I. 469). Azo-benzol- 
 m-monoearboxylic acid, m.p. 171. Azo-benzol-p-monocarboxylic acid 
 C 6 H 5 N 2 C 6 H 4 [4]COOH, m.p. 238, is obtained from p-amido-azo-benzol, 
 by way of the cyanide, and from benzol-azo-p-toluol by oxidation with 
 chromic acid (A. 303, 385). 
 
 o-Tolyl-azo-benzoic acid CH 3 [2]C 6 H 4 N : NC 6 H 4 [2]COOH, m.p. 148, 
 from o-nitro-toluol by the action of finely divided metals and alkaline 
 hydrate (C. 1903, II. 973). m- and p-Benzaldehyde-azo-m- and 
 -p-benzoie acid CHOC 6 H 4 N 2 CgH 4 COOH is formed from m- and p-azoxy- 
 benzaldehyde by transposition with concentrated H 2 SO 4 (B. 36, 
 3469, 3801). 
 
 12. Hydrazin-benzoie Acids. The symmetrical hydrazo-benzoic 
 acids result when the azo-benzoic acids are reduced with sodium 
 amalgam, or with ferrous sulphate and sodium hydroxide. o-Hydrazo- 
 benzoic acid melts at 205. m-Hydrazo-benzoic acid CO 2 H[3]C 6 H 4 
 [i]NH.NH[i']C 6 H 4 [3']CO 2 H. These two acids, . when boiled with 
 hydrochloric acid, rearrange themselves to diamido-diphenyl-dicar- 
 boxylic acids (q.v.). The rearrangement of the m-acid into p-diamido- 
 diphenic acid is of importance for the proof of the constitution of 
 diphenic acid (q.v.), and consequently that of phenanthrene. 
 p-Hydrazo-benzol-carboxylie acid C 6 H 5 NHNHC 6 H 4 [4]COOH, m.p. 193, 
 on transposition gives benzidin, with liberation of CO 2 (A. 303, 384). 
 
 o-, m- and p-Hydrazin-benzoie acids NH 2 .NH.C 6 H 4 .CO 2 H result 
 when the hydrochlorides or nitrates of diazo-benzoic acids are reduced. 
 
 o-Cyano-phenyl-hydrazin NH 2 NH[2]C 6 H 4 CN, m.p. 153, from 
 o-diazo-benzo-nitrile by reduction, seems also to be formed by the 
 
 reduction of the pheno-j8-triazone oxime C 6 H 4 |^ (NOH) -^ H (B. 36, 805). 
 
 o-, m-, p-Benzoie-thionyl-hydrazone SO : NNHC 6 H 4 COOH, m.p. 
 155, 231, 258 (B. 27, 2555). Benzylidene-o-hydrazin-benzoic acid 
 C 6 H 5 CH : NNH.C 6 H 4 COOH, m.p. 224, is reduced by sodium amalgam 
 to o-benzyl-hydrazin-benzoic acid C 6 H 5 CH 2 NHNHC 6 H 4 COOH, m.p. 
 134 with decomposition. On heating alone, or, better, with POC1 3 in 
 an open vessel, o-hydrazin-benzoic acid yields an inner anhydride, 
 
 o-hydrazin-benzoie lactazame C 6 H 4 ^ NH /NH, m.p. 242 with decom- 
 position; while, on heating with POCL under pressure, chlorindazol 
 CCK 
 
 >NH is formed (B. 35, 2315). 
 
 (CC 
 6 H 4 j I 
 
 13. Phosphine - benzoic Acids. Trimethyl-phospho-p-benzo-beta'in 
 
 r [i]CO \ 
 
 C 6 H 4 c r 4 -ip/cH ) / * s obtained from p-tolyl-trimethyl-phosphonium 
 chloride by oxidation with alkaline permanganate ; similarly, the 
 trimethyl - phospho - tolu - betain is formed from trimethyl - xylyl - 
 phosphonium chloride (B. 31, 2919). 
 
 14. Sulpho-benzoie Acids. On conducting the vapours of SO 3 into 
 benzoic acid, we obtain as chief product m-sulpho-benzoic acid, and in 
 smaller amount p-sulpho-benzoic acid (A. 178, 279). 
 
 The three isomerides can be obtained by oxidising the three toluol- 
 sulphonic acids with an alkaline solution of potassium permanganate. 
 
 If the toluol sulphamides, instead of the free acids, be subjected to 
 similar oxidation, the m- and p-toluol sulphamides yield m- and p- sulph- 
 
SULPHO-BENZOIC ACIDS 313 
 
 amine-benzoic acids ; whereas the o-toluol sulphamide changes to 
 benzole sulphinide, or anhydro-sulphamine-benzoic acid, called 
 saccharin (B. 12, 469), from which, by saponification with HC1, the 
 o-sulpho-benzoic acid is obtained (B. 33, 3485). o- and p-sulpho- 
 benzoic acid are formed together on boiling potassium-m-nitro-benzol 
 sulphonate with an aqueous solution of KI ; as in the formation of 
 chloro-benzoic acids from halogen nitro-benzols with KCN, the entering 
 cyanogen group does not take the place of the expelled nitro-group 
 (C. 1905, II. 230). 
 
 o-Sulpho-benzoic acid SO 3 H[2]C 6 H 4 CO 2 H+3H 2 O, m.p. 141 (anhy- 
 drous) behaves somewhat like phthalic acid (q.v.). It forms, for 
 instance, phthale'ins (q.v.) (C. 1898, II. 717, 1105), an anhydride, and 
 an imide. By the action of PC1 5 two dichlorides are obtained, m.p. 
 40 and 79, the more stable one with the higher melting-point being 
 
 probably represented by the formula C 6 H 4 < ri , and the other 
 
 V. v3v-/2^-'-l 
 
 by the formula C 6 H 4 / 2 \D. On boiling with alcohols they 
 
 yield ester-sulphonic acids SO 3 HC 6 H 4 COOR ; with sodium ethylate, 
 o-sulpho-benzoic-diethyl ester, b.p. 22 212 ; with ammonia, the sym. 
 chloride (m.p. 79) gives benzoyl sulphinide, while the unsym. 
 unstable chloride gives chiefly o-eyano-benzol-sulphonic acid CN[i] 
 C 6 H 4 [2]SO 3 H, m.p. 279 (chloride, m.p. 67-5), which has also been 
 obtained from o-aniline-sulphonic acid by way of the diazo-compound 
 (B. 28, R. 751). With aniline the chlorides form o-sulpho-benzoic 
 
 anile C 6 H 4 <^ 2 )>NC 6 H 5 , m.p. 190, sym. dianilide C 6 H 4 (CONHC 6 H 5 ) 
 S0 2 NHC 6 H 5 , m.p. 195, and unsym. dianilide C 6 H/^ NHC H6)8 
 
 - 
 
 m.p. 270-28o with decomposition ; while, with POC1 3 , the two last give 
 the dianile c 6 H/^ : NC6H5 ^NC 6 H 5 , m.p. 189. 
 
 \oCj2 - r- 
 
 On reduction the unstable chloride gives sulpho-benzide, and the 
 stable chloride gives thio-salicylic acid SH.C 6 H 4 COOH. Condensation 
 with benzene and A1 2 C1 6 gives mainly the sym. product C 6 H 5 COC 6 
 H 4 SO 2 C 6 H 5 . The unsym. triphenyl-methane derivative is also obtained, 
 
 (C 6 H 5 ) 2 C.C 6 H 4 SO 2 6 (B. 31, 1648 ; C. 1906, II. 329). p-Nitro- and 
 p-bromo-o-sulpho-benzoic acids, with PC1 5 , also give two isomeric 
 dichlorides each, which are transformed in a similar manner (C. 1904, 
 I. 274, 369). 
 
 o-Sulpho-benzoic anhydride, m.p. 118, from the acid with acetyl 
 chloride. With benzene and Al chloride it yields benzo-phenone-o- 
 sulphonic acid C 6 H 5 CO.C 6 H 4 SO 3 H (B. 33, 3486) ; the isomeric phenyl- 
 sulphone-o-benzoic acid C 6 H 5 .SO 2 .C 6 H 4 COOH, m.p. 268, is formed 
 from phenyl-o-tolyl sulphone by oxidation (C. 1901, I. 692). 
 
 o-Sulpho-chloride-benzoie methyl ester SO 2 C1.C 6 H 4 COOCH 3 , m.p. 
 65, from o-benzo-sulphinic-acid ester SO 2 H.C 6 H 4 COOCH 3 , m.p. 99, 
 treated with chlorine. This ester is prepared from anthranilic acid 
 ester by diazotating, and replacing the diazo-group by the sulphinic 
 residue (C. 1901, II. 961). 
 
 o - Sulphamido - benzoic acid NH 2 SO 2 [2]C 6 H 4 [i]COOH melts at 
 I53-I55, with transition into the sulphinide, Methyl and ethyl 
 
3 i4 ORGANIC CHEMISTRY 
 
 ester, m.p. 119 and 84 respectively (C. 1899, I. 1093). The acid is 
 formed by the oxidation of o-toluol-sulphamide with red prussiate of 
 potash (B. 19, R. 689), and from its inner anhydride with warm alkaline 
 hydrate. On fusing sulpho-benzoic acid with ammonium sulpho- 
 cyanide the isomeric o-benzamido-sulphonic acid is formed, C 6 H 4 
 (CONH 2 )SO 3 H, m.p. 194, which, with potassium hypobromite, yields 
 o-sulphanilic acid (B. 29, R. 102). 
 
 o - Anhydro - sulphamine - benzole aeid, benzoic sulphinide 
 
 Je > / NH > called saccharin, melts at 220. It was discovered 
 
 in 1879 by Ira Remsen and C. Fahlberg. Its preparation is given 
 above. This compound is now made technically in very large quanti- 
 ties. It is used for sweetening purposes. It is 500 times sweeter than 
 cane sugar. It dissolves with difficulty in cold water, and, like succin- 
 imide and phthalimide, behaves like a strong acid, forming imide salts. 
 
 The sodium salt c e H 4^Hso / NNa is ver y rea dily soluble in water, and 
 is 400 times sweeter than cane sugar. It is readily transposed by such 
 haloid derivatives as benzyl chloride and acetyl chloride to N-deriva- 
 tives of saccharin (B. 25, 1737 ; 29, 1048). 
 
 o- Sulpho-benzoic anile C 6 H 4 ^^ 2 ^>N.C 6 H 5 , melting at 190, results 
 
 from the action of aniline upon the chlorides of sulpho-benzoic acid 
 (B. 29, R. 353). Phosphorus pentachloride converts saccharin into 
 
 pseudo-saccharin chloride W^j^J^N, melting at 149 (B. 29, 2995). 
 At 7o-75 o-cyano-benzol-sulpho-chloride is formed (B. 29, 2295 ; 
 C. 1906, I. 1609). With phenols and amido-phenols saccharin con- 
 denses to dyes of the phthalein type, called sacchareins (C. 1897, II. 847 ; 
 1899, I. 718). 
 
 All sulpho-acids containing the sulpho-group in the o-position with 
 reference to the carboxyl group of an alkyl-benzoic acid are capable 
 of forming sulphinides or sulpho-carbonimides (B. 25, 1737). 
 
 On esters and ester acids from o- and p-sulpho-benzoic acid, see 
 M. 23, 1093. 
 
 3, 5-Disulpho-benzoic acid is formed by heating benzoic acid with 
 fuming sulphuric acid containing 70 per cent. SO 3 to 250 in a pressure 
 tube (B. 35, 2305). 2, 4-Disulpho-benzoie acid, from 2, 4-toluol- 
 disulphonic acid (B. 14, 1205). 
 
 Diphenyl-sulphone-o-monoearboxylic acid C 6 H 5 SO 2 [2]C 6 H 4 [i]COOH, 
 m.p. 144, is formed by oxidation of phenyl-o-tolyl-sulphone and 
 phenyl-thio-salicylic acid with KMnO 4 , or by heating the potassium 
 salts of o-chloro-benzoic acid and benzol-sulphinic acid in aqueous or 
 amyl-alcoholic solution, in the presence of copper. On heating with 
 concentrated H 2 SO 4 the acid passes into benzo-phenone-sulphone 
 
 (B. 38, 729 ; C. 1905, I. 1394)- 
 
 (d) MONOHYDRIC OXY-PHENYL-PARAFFIN ALCOHOLS AND THEIR 
 
 OXIDATION PRODUCTS. 
 
 i. Monohydrie Oxy-phenyl-paraffin Alcohols, or Phenol Alcohols. 
 
 These alcohols contain, in addition to the alcoholic hydroxyl, other 
 hydroxyl groups joined to the benzene nucleus, which impart to them 
 
MONOHYDRIC OXY-PHENYL-PARAFFIN ALCOHOLS 315 
 
 the character of phenols. Some of the alcohols of this group are 
 simple transposition products of long-known plant-substances. Special 
 interest attaches to a number of mono- and dioxy-phenyl-ethyl-amines 
 on account of their strong physiological action, and their occurrence 
 in animals and plants ; cp. p-oxy-phenyl-ethyl-amine and hordenin. 
 
 Formation. Some of the methods described under the benzyl 
 alcohols also lead to phenol alcohols : 
 
 (1) The reduction of corresponding aldehydes and ketones. 
 
 (2) The treatment of aldehydes with caustic alkali. 
 
 (3) The action of sodium amalgam upon amides (B. 24, 175). 
 
 (4) They are linked to the benzyl alcohols through the amido- 
 phenyl-paraffin alcohols, which nitrous acid converts into oxy-phenyl- 
 paraffin alcohols. 
 
 (5) Nuclear Synthesis. Methylene chlorides (B. 13, 435) or form- 
 aldehyde and sodium hydroxide (B. 27, 2411 ; 35, 3844 ; 40, 2524 ; 
 J. pr. Ch. 2, 50, 225) change phenols into phenyl alcohols. Phenols 
 with so-called " negative " substituents (NO 2 , Cl, CHO, COOH) con- 
 dense with formaldehyde and HC1 to oxy-benzyl chlorides, in which the 
 chlorine atom is very easily replaced by OH or OR (B. 34, 2455 ; C. 
 1902, II. 894) ; (6) by the action of alkyl-magnesium haloids upon 
 phenol-carboxylic ester. Closely related to formation (5) of the phenyl 
 alcohols is the nuclear-synthetic formation of acylated oxy-benzyl- 
 amines by the condensation of phenols with N-methylol-acyl-amides 
 RCONHCH 2 OH (A. 343, 215). 
 
 Monoxy-benzyl Alcohols HOC 6 H 4 .CH 2 OH. The three theoretically 
 possible isomerides have been prepared. They result when the corre- 
 sponding aldehydes are reduced with sodium amalgam. Saligenin, or 
 o-oxy-benzyl alcohol, is the best-known member of the group : 
 
 o-Oxy-benzyl alcohol . . . m.p. 82 
 m-Oxy-benzyl alcohol . . 67 
 
 p-Oxy-benzyl alcohol 110. 
 
 Saligenin, or o-oxy-benzyl alcohol, was first obtained in the decom- 
 position of the glucoside salicin (q.v.) by means of emulsin, ptyalin, or 
 dilute acids (Piria, 1845 ; A. 56, 37) : 
 
 C 6 H u O 5 .O.C 6 H 4 .CH a OH+H a O - HO.C 6 H 4 CH 2 OH+C 6 H 12 O 6 . 
 
 Saligenin has also been prepared by the usual methods, from salicyl- 
 aldehyde, salicyl-amide, o-amido-benzyl alcohol, and phenol. It is 
 soluble in hot water, alcohol, and ether. Ferric chloride produces 
 a deep-blue colour in its solutions. Acids resinify it, forming salinetin 
 (farivr), resin). Ethers and substitution products of saligenin are 
 known. These have been made in part from the corresponding 
 salicyl derivatives. 
 
 o-Oxy-benzyl-amine, salicyl-amine, melts at 121 (B. 23, 2744). 
 o-Oxy-benzyl-aniline, m.p. 108, is also obtained by combining anhydro- 
 formaldehy de-aniline with phenol (C. 1900, II. 457 ; A. 315, 138). The 
 O-acetyl compounds of o-oxy-benzyl-amines and -anilines are unstable, 
 and transpose spontaneously into the isomeric N-acetyl compounds 
 (A. 332, 159). Steric resistances are encountered in the acetylation 
 pf substituted o-oxy-benzyl-anilines (B. 32, 2057). 
 
3 i6 ORGANIC CHEMISTRY 
 
 Anisyl alcohol, p-methoxy-benzyl alcohol CH 3 O[4]C 6 H 4 [i].CH 2 .OH, 
 is obtained from anisic aldehyde by alcoholic potassium hydroxide. 
 It melts at 45, and boils at 259. It forms anisic aldehyde when 
 oxidised. 
 
 p-Homo-saligenin CH 3 [5]C 6 H 3 [2](OH)CH 2 .OH melts at 105, from 
 p-cresol by method 5 (B. 42, 2539). 
 
 p-Thymotin alcohol CH 3 [2]C 3 H 7 [5]C 6 H 2 [4]OH[i]CH 2 OH, m.p. 120 
 (B. 27, 2412). 
 
 o-Oxy-phenyl-ethyl alcohol HO[2]C 6 H 4 [i]CH 2 CH 2 OH, b.p. 169, is 
 
 ( [i]CH : CH 
 formed by the splitting up of cumarone C 6 H 4 < I (q*v.) with 
 
 l[ 2 ]0 
 
 alcoholic potash, besides oxy-phenyl-acetic acid; the bromide of the 
 alcohol, on treatment with NaHO, gives the cyclic phenol-alcohol ether, 
 
 the so-called hydro-cumarone C 6 HJ ' I 2 , m.p. 188, also formed 
 
 l[2]0 ! 
 
 from cumarone by reduction with Na and alcohol, and from bromo- 
 methyl-o-bromo-phenyl ether BrC 6 H 4 OCH 2 .CH 2 Br by condensation 
 with sodium. o-Oxy-phenyl-ethyl-amine HO[2]C 6 H 4 [i]CH 2 CH 2 NH 2 , 
 with a chlorohydrate of m.p. 153, is formed from the hydrazide of 
 melilotic acid by disintegration. The quaternary iodo-methylate of 
 the base, obtainable by the action of ICH 3 , melts at 218. On heating 
 with NaHO it splits off trimethyl-amine and yields hydro-cumarone 
 (B. 38, 2067). p-Oxy-phenyl-ethyl-amine HQ[4]C 8 H 4 [i]CH 2 CH 1 NH f , 
 m.p. 162, increases the blood-pressure, like the closely related adrena- 
 lin (q.v.). It is formed from tyrosin (q.v.), an important product of 
 the decomposition of albumin, by further decomposition, or by heating 
 with rejection of CO 2 . Synthetically, the p-oxy-phenyl-ethyl-amine 
 is obtained by reduction of oxy -benzyl cyanide, or from the anisylidene- 
 nitro-methane CH 3 O[4]C 6 H 4 [i]CH : CHNO 2 by reduction and saponifi- 
 cation with HI (B. 42, 4778). By methylation of p-methoxy-phenyl- 
 ethyl-amine and saponification of the methoxyl group with HI, we 
 obtain p-oxy-phenyl-dimethyl-ethyl-amine, hordenin HO[4]C 6 H 4 [i]CH 2 
 CH 2 N(CH 3 ) 2 , m.p. 117, an alkaloid forming the effective ingredient of 
 barley seeds (B. 43, 306). 
 
 p-Oxy-phenyl-iso-propyl-amine HOC6H 4 CH 2 .CH(NH 2 )CH 3 , m.p. 
 126, by reduction of p-oxy-phenyl-acetoxime (B. 43, 192). 
 
 o-Oxy-phenyl-ethyl-carbinol HO[2]C 6 H 4 CH(OH)C 2 H 5 , b.p. . 25 125- 
 130* by reduction of o-oxy-phenyl-ethyl ketone, and synthetically 
 from tetra-acetyl-helicin with zinc ethyl (C. 1902, II. 214 ; B. 36, 
 
 2575). 
 
 o-Oxy-phenyl-diethyl-carbinol HO[2]C 6 H 4 C(OH)(C 2 H 5 ) 2 , m.p. 57, 
 from salicylic ester, with C 2 H 5 MgI. It easily splits off water, and 
 passes into olefm-phenol (C. 1903, I. 1222). 
 
 o-Chloro-p-oxy-benzyl alcohol and p-chloro-o-oxy-benzyl alcohol 
 C1C 6 H 3 (OH)CH 2 OH ; also o-nitro-p-oxy- and p-nitro-o-oxy-benzyl 
 alcohol, are produced in the form of their easily saponified haloid esters 
 (see Pseudo-phenol haloids) from chloro- and nitro-phenols with form- 
 aldehyde and halogen hydride. The p-amido-saligenin NH 2 [4]C 6 H 3 
 [2]OH[i]CH 2 OH, formed by reduction of p-nitro-o-oxy-benzyl alcohol, 
 is used as a photographic developer, under the name " edinol " (B. 34, 
 2455 ; C. 1902, II. 394, 1439). 
 
PSEUDO-PHENOL ALCOHOL HALOIDS 317 
 
 PSEUDO-PHENOL HALOIDS, METHYLENE-QUINONES, QUINOLS. 
 
 Pseudo-phenol Alcohol Haloids. A peculiar behaviour is shown by 
 certain halogen-hydrogen esters of phenol alcohols, especially those 
 o- and p-oxy-benzyl bromides and chlorides in which nuclear H atoms 
 are replaced by chlorine or bromine. Such products are obtained (i) 
 by the action of HBr upon the corresponding phenol alcohols ; (2) from 
 vinyl phenols by adding HBr or Br 2 ; (3) by suitable bromination of 
 o- and p-alkyl phenols, e.g. : 
 
 o-Oxy-mesityl chloride C 6 H 2 [3, 5](CH 3 ) 2 [ 2 , i](OH)CH 2 Cl, m.p. 58. 
 o-Oxy-iso-duryl chloride C 6 H[3, 5, 6](CH 3 ) 3 [2, i](OH)CH 2 Cl, m.p. 100. 
 m-Bromo-o-oxy-benzyl bromide C 6 H 3 [3]Br[2,i](OH)CH 2 Br, m.p. 98. 
 m,m-Dibromo - o - oxy - benzyl bromide C 6 H 2 [3, 5]Br 2 [2, i](OH)CH 2 Br, 
 m.p. 117. Tribromo-o-oxy-benzyl bromide C 6 HBr 3 [2, i](OH)CH 2 Br, 
 m.p. 134. Tetrabromo-o-oxy-benzyl bromide C 6 Br 4 [2, i](OH)CH 2 Br, 
 m.p. 156. Dibromo-o-oxy-mesityl bromide C 6 Br 2 (CH 3 ) 2 [2, i](OH) 
 CH 2 Br, m.p. 150. Bromo-o-oxy-iso-duryl bromide C 6 Br(CH 3 ) 3 [2, i] 
 (OH)CH 2 Br, m.p. 112. m, m-Dibromo-p-oxy-benzyl bromide C 6 H 2 Br 2 
 [4, i](OH)CH 2 Br, m.p. 150. Dibromo-p-oxy-pseudo-cumyl bromide 
 C 6 Br 2 (CH 3 ) 2 [4, i](OH)CH 2 Br, m.p. 126. Dibromo-p-oxy-mesityl 
 bromide, m.p. 147. Tetrachloro-p-oxy-benzyl bromide C 6 C1 4 [4, i] 
 (OH)CH 2 Br, m.p. 160, and chloride, m.p. 146. Penta-, hexa,- and 
 heptabromo-p-ethyl-phenol C 6 HBr 3 [4, i](OH)CHBr*CH 2 Br, C 6 HBr 3 
 [4, i](OH)CHBr*CHBr 2 and C 6 Br 4 [4, i](OH)CHBr*CHBr 2 , Tetra- 
 bromo-iso-eugenol C 6 HBr 2 [3]OCH 3 [4, i](OH)CHBr*CHBrCH 3 . Hepta- 
 bromo-p-iso-propyl-phenol C 6 Br 4 [2, i](OH)CBr*(CHBr 2 )CH 3 ,m.p. 183, 
 etc. 
 
 These substances are insoluble in alkalies, and show an abnormal 
 mobility of one aliphatically linked Br atom. This Br atom, on treat- 
 ing with water, alcohol, glacial acetic acid, amines, potassium cyanide, 
 or sulpho-hydrate, is easily exchanged for the residues OH, OA1K, 
 OCOCH 3 , NHR, CN, SH ; with phenols, and tertiary amines of the 
 dimethyl-aniline type, they transpose very easily, without condensing 
 agents, into diphenyl-methane derivatives. A reactivity similar to 
 that of the pseudo-phenol alcohols is possessed by the corresponding 
 sulpho-cyanides, acetates, and nitro-bodies, such as C 6 Br 2 (CH 3 ) 2 [4, i] 
 (OH)CH 2 NO 2 (B. 34, 4264 ; cp. also the analogous behaviour of pro- 
 penyl-phenyl dibromides). To explain the behaviour of these sub- 
 stances, called " pseudo-phenols " on account of their insolubility in 
 alkalies, it is assumed that, in consequence of hitherto unexplained 
 influences, the CH 2 Br (or CHBr) group so closely approaches the 
 para- or ortho-hydroxyl that, in most reactions, there is a splitting 
 off of HBr in the first instance, leading to the formation of highly 
 reactive "methylene-quinones" or " quinone-methanes " (B. 36, 2336), 
 which react further with addition of the agents ; or the pseudo- 
 phenol bromides are regarded as quinone-like substances, corre- 
 sponding to the scheme : 
 
 BrCH 2 <_ . 
 
 CH 2 . 
 
 H' 
 
 Pseudo-phenol bromides Methylene-quinones Phenol alcohols. 
 
3i8 ORGANIC CHEMISTRY 
 
 In their other chemical properties the pseudo-phenols correspond 
 exactly to the phenols, being easily converted into O-acetyl compounds 
 and urethanes. 
 
 Methylene-quinones. The methylene-quinones, assumed above as 
 intermediate products, may be obtained from the o- and p-pseudo- 
 phenol bromides by treatment with sodium acetate solution, or dilute 
 alkaline hydroxide. The o-methylene-quinones are formed much 
 more easily than the para-bodies, the latter easily passing into poly- 
 merised products, and, partly, into condensation products soluble in 
 alkalies, e.g. derivatives of p 2 -dioxy-diphenyl-methane. 
 
 From the pseudo-bromides of p-ethyl-phenol, iso-eugenol, and 
 p-iso-propyl-phenol, on the other hand, derivatives of p-ethylidene- 
 p-propylidene and p-iso-propylidene-quinone can be isolated. The 
 methylene-quinones are yellow substances, easily polymerised and 
 bleached, by light or by acids. The chemical behaviour of the o- and 
 p-methylene-quinones shows a remarkable difference. The para-bodies 
 are highly reactive, easily combining with water, alcohols, acetic acid, 
 and H haloids to form the corresponding phenol-alcohol derivatives ; 
 whereas the o-methylene-quinones are quite indifferent, so that they 
 can hardly be regarded as intermediate products in the transformations 
 of the o-pseudo-phenol haloids. 
 
 o-Iso-durylene-quinone CH 2 : [i]C 6 H(CH 3 ) 3 [2] : O, m.p. 129. Tetra- 
 bromo-o-methylene-quinone CH 2 : [i]C 6 Br [2] : O, m.p. ca. 130. Bromo- 
 o-iso-durylene-quinone CH 2 : [i]C 6 Br(CH 3 ) 3 [2] : O, m.p. 155. Dibromo- 
 dimethyl-o-methylene-quinone CH 2 : [i]C 6 Br 2 (CH 3 ) 3 |>] : O, m.p. 168. 
 Hexabromo-p-ethylidene-quinone CHBr 2 CH : [i]C 6 Br [4] : O. Tribromo- 
 methoxy-p-propylidene-quinone CH 3 CHBrCH : [i]C 6 HBr 2 (OCH 3 )[4] :O. 
 Heptabromo-p-iso-propylidene-quinone CH 3 (CHBr 2 )C : [i]C 6 Br 4 [4] : O, 
 m.p. 185. Cp. also the much more stable methylene-quinones of the 
 di- and triphenyl-methane series, e.g. diphenyl-methylene-quinone and 
 quino-diphenyl-m ethane, the dyestuffs of the benzo-phenone and tri- 
 phenyl-carbinol group, such as auramin, rosaniline, rosolic acid, etc., 
 must be regarded as derivatives of methylene-quinone. 
 
 Literature. See Auwers, A. 301, 203 ; 334, 264 ; 344, 93 ; B. 32, 
 2978 ; 34, 4256 ; 36, 1878 ; 38, 3302 ; 39, 3160 ; Zincke, A. 320, 145 ; 
 322, 174 ; 329, i ; 349, 67 ; 350, 269 ; 353, 357. 
 
 Quinols. Related to the pseudo-phenols and methylene-quinones 
 is the species of compounds known as quinols, which are also related to 
 the quinones proper. 
 
 (1) Quinols were first obtained from para-alkylated bromine- or 
 chlorine-substituted phenols, by oxidation with nitric acid or nitrogen 
 oxides, the so-called nitro-ketones, or quinitrols, being intermediate 
 products : 
 
 NOaH CH 3 \H Cl Acetate CH 8 \H Cl . n 
 
 ~ NO/ir-cT : ( HO/-R cT 
 
 Dichloro-p-cresol Dichloro-tolu-quinitrol Dichloro-tolu-quinol. 
 
 Caro's acid also oxidises the non-substituted p-alkyl-phenols, like 
 p-cresol, 2, 4-xylenol, in small quantities, to quinol (B. 36, 2028). 
 
 (2) The simplest representatives of this series were obtained from 
 p-alkyl-phenyl-hydroxylamines by transposition with H 2 SO 4 ; the 
 
QUINOLS 319 
 
 imine-quinols, obtained as intermediate products, become quinols, by 
 splitting off NH 3 : 
 
 NHOH * /~ " : NH 
 
 HOH H 
 
 p-Tolyl-hydroxylamine Imino-tolu-quinol Tolu-quinol. 
 
 Similarly, the p-alkyl-phenyl-hydroxylamines, heated with alcoholic 
 H 2 SO 4 , give imino-quinol ether and quinol ether : 
 
 : NH _* : O 
 
 m-Xylyl-/3-hydroxylamine Imino-xylo-quinol-ethyl Xylo- quinol- ethyl ether. 
 
 ether 
 
 (3) Small amounts of quinols are also obtained from quinones, by 
 the action of magnesium-methyl iodide. 
 
 The quinols are colourless substances, soluble in alkalies, and subject 
 to acidulation ; they are easily reduced to p-alkyl-phenols, from which 
 they may be partly recovered by oxidation. 
 
 On the plan of the a, j8-olefin-ketones, the simplest quinols combine 
 with two molecules of hydroxylamine to form j3-hydroxylamine-oximes 
 (cp. Vol. I.). With phenyl-hydrazin, various substances are formed 
 according to the conditions, phenyl-hydrazino-compounds, diphenyl- 
 hydrazones of diketo-oxy-tetrahydro-benzols, or azo-compounds with 
 rejection of H 2 O. 
 
 With alkyl-magnesium haloids the quinols yield diquinols by method 
 3 (above) : 
 
 CH 3 \ Br Br c.H,Mgl CH 3 \ Br Br /C 2 H 5 
 
 OH/ Br Br : * OH/ Br Br \OH 
 
 Tetrabromo-tolu-quinol Tetrabromo-methyl-ethyl-diquinol. 
 
 The quinols have a characteristic tendency towards intramolecular 
 atomic displacements. We may mention the migration of the para- 
 alkyl group brought about by sulphuric acid, with formation of hydro- 
 quinones : 
 
 CH 3 \ H CH 3 H CH 3 
 
 HO>H-Hr : - HQ CH 3 H QH 
 
 2., 4-Dimethyl-quinol p-Xylo-hydroquirione. 
 
 In the quinol ethers this transposition takes two directions, resorcin 
 ethers being formed with migration of the alkoxyl group, besides hydro- 
 quinone ethers, on heating with alcoholic H 2 SO 4 . 
 
 On heating with concentrated H 2 SO 4 , the halogen-substituted 
 methyl-quinols split off formaldehyde, and pass into p 2 -dioxy-diphenyl- 
 methanes. An analogous behaviour is shown by the isomeric p-oxy- 
 benzyl alcohols and their derivatives, the pseudo-phenol bromides, 
 intermediate products being probably the methylene-quinones (A. 356, 
 124). Tetrabromo-ethyl-quinol, on being treated with concentrated 
 H 2 SO 4 , gives tribromo-ethyl-quinone (A. 341, 262). 
 
 In the halogen-substituted quinols the halogen atom, occupying 
 the o-position with reference to the quinol group, may be replaced by 
 OH, NHC 6 H 5 , etc. (cp. chloranile). 
 
 Instead of the expected quinol, nitro-chloro-p-cresol yields nitro- 
 chloro-tolu-quinone on heating with HNO 3 , the quinol undergoing trans- 
 
320 ORGANIC CHEMISTRY 
 
 position to hydroquinone, and oxidation. Nitro-bromo- and nitro- 
 dibromo-p-cresol behave similarly (A. 341, 310). The atomic dis- 
 placement may also take other directions, according to the structure 
 of the quinols (cp. B. 35, 443). 
 
 p-Tolu-quinol CH 3 (OH)[4]C 6 H 4 : O, m.p. 75, from p-tolyl-hydro- 
 xylamine with dilute sulphuric acid, and, in small quantities, from 
 p-cresol with Caro's acid. 
 
 2, 4-Dimethyl-qmnol CH 3 (OH)[4]C 6 H 3 [2](CH 3 ) : O, m.p. 73, from 
 m-xylyl-j8-hydroxylamine, with cold dilute H 2 SO 4 , yields, on heating 
 with acids or alkalies, or on illumination, p-xylo-hydroquinone. 2, 4-Di- 
 methyl-quinol-ethyl ether CH 3 (OC 2 H 5 )L4JC 6 H 3 |2](CH 3 ) : O, b.p. 12 94. 
 Imino-2,4-dimethyl-quinol-ethyl ether CH 3 (OC 2 H 5 )[4]C 6 H 3 [2](CH 3 ) : 
 NH, b.p. n 98, from m-xylyl-jS-hydroxylamine with alcoholic H 2 SO 4 . 
 Mesityl-quinol CH 3 (OH)[4]C 6 H 2 [2, 6](CH 3 ) 2 : O, m.p. 46, from mesityl- 
 hydroxylamine, is transposed into cumo-hydroquinone. 2, 4, 5-Tri- 
 methyl-quinol, m.p. 116, from pseudo-cumenol with Caro's acid, and- 
 from p-xylo-quinone with CH 3 MgI (B. 36, 2038). Di-, tri-, and tetra- 
 chloro-tolu-quinols, m.p. 123, 90, and 166, from di-, tri-, and tetra- 
 chloro-p-cresol, with HNO 3 , either direct, or by way of the quiriitrols 
 (method i). 
 
 Di-, tri-, and tetrabromo-tolu-quinol, m.p. 134, 128, and 205. On 
 treating with alcoholic HC1, two bromine atoms are replaced by chlorine 
 in the tetrabromo-tolu-quinol, and one Br atom in the tribromo-tolu- 
 quinol, forming respectively : dibromo-dichloro-tolu-quinol, m.p. 162, 
 and dibromo-ehloro-tolu-quinol, m.p. 135. Tetrabromo-ethyl-quinol 
 C 2 H 5 (OH)[4]C 6 Br 4 : O, m.p. 140. Tetrabromo-methyl-ethyl-diquinol 
 CH 3 (OH)[i]C 6 Br 4 [4](OH)C 2 H 5 , m.p. 191, and tetrabromo-diethyl- 
 quinol C 2 H 5 (OH)[i]C 6 Br 4 [4](OH)C 2 H 5 , m.p. 180, are formed from 
 tetrabromo-ethyl-quinol with methyl- and ethyl-magnesium iodide re- 
 spectively. 
 
 The pseudo-phenol bromides also are oxidised by HNO 3 to quinols, 
 which, on treatment with alkalies or silver oxide, yield oxides with 
 rejection of HBr. 
 
 Br Br CH 2 Br\ Br Br CH 2 \ Br Br 
 
 Pentabromo-p-cresol Pentabromo-tolu-quinol Pentabromo-tolu-quinol 
 
 oxide. 
 
 These oxides add HBr and acetyl bromide, with formation of hydro- 
 quinone derivatives : 
 
 HBr R rH ^ Br Br ^ 
 
 CH 2 \ Br Br Q f 2 ^~ fiT 
 
 V+' K^ ?, \ CH 8 COBr ? p 
 
 Tetrabromo-tolu- iir 
 
 quinol oxide. 
 
 Literature. Cp. Auwers, B. 35, 425, 443 ; Bamberger, B. 33, 3600 ; 
 35, 1424, 3886 ; 36, 1625 ; 40, 1890, 2236 ; Zincke, B. 34, 253 ; A. 328, 
 261 ; 343, 100 ; 341, 309. 
 
 Dioxy-benzyl alcohols are not known in a free condition, but deriva- 
 tives of 2, 5-dioxy- and of 3, 4-dioxy-benzyl alcohol have been obtained 
 in the reduction of certain aldehyde ethers with sodium amalgam. 
 Di-methyl-gentisin alcohol (CH 3 O) 2 [2, 5]C 6 H 3 [i]CH 2 .OH boils at 278. 
 
PHENOL-ALDEHYDES 321 
 
 Vanillyl alcohol CH 3 O[3]HO[4]C 6 H 3 [i]CH 2 .OH, from vanillin, 
 melts at 115. 
 
 Piperonyl alcohol CH 8 /^\ c 6 H 3 [i]CH 2 .OH, from piperonal, melts 
 
 \O[4J J 
 
 at 51. Homo-piperonyl alcohol CH a / O[3 ^\c 8 H 3 CH 2 CH a OH, b.p. 10 156, 
 see B. 41, 2752. o-Dioxy-benzyl-amine melts at 168 (B. 27, 1799). 
 
 (2) AROMATIC OXY-MONO-ALDEHYDES, PHENOL-ALDEHYDES. 
 
 The phenol-aldehydes are obtained (i) by oxidising the phenol alco- 
 hols with chromic acid ; (2) by an important nuclear-synthetic method, 
 consisting in letting chloroform and an alkaline hydroxide act upon 
 phenols (reaction of Reimer) , when the chloroform enters the o- and p- 
 position with reference to the phenol-hydroxyl, and is then converted 
 into the aldehyde group (B. 9, 1268) : 
 
 C,H 5 .OH+CHC1 3 +4KOH = C,H 4 /^ O +3KC1 + 3H a O. 
 
 On treating o- and p-alkylated phenols with chloroform and alkali, 
 some chlorinated products of a ketone type, insoluble in alkalies, are 
 produced besides the phenol-aldehydes, e.g. 
 
 rw H H CH 3 \H H , 
 
 ' Ha ~ IT * CHC1 2 /"H H" 
 
 These substances should be regarded as derivatives of keto-dihydro- 
 benzol, and are dealt with in that connection. 
 
 (3) A nuclear synthesis of phenol-aldehydes is also brought about 
 by the action of prussic acid and gaseous HC1 upon the phenols, or their 
 ethers, with or without Al chloride ; aldimines are first formed, and 
 these are easily converted into aldehydes (Gattermann, A. 357, 313) : 
 
 C 6 H 5 OH HNC(HC1 U HN : CH.C 6 H 4 OH - > OCH.C 6 H 4 OH. 
 
 By similar reactions, oximes of phenol-aldehydes are produced (30) 
 from multivalent phenols, mercury fulminate, and HC1 ; and phenyl- 
 imines of aldehydes (36) from multivalent phenols, formanilide, and 
 POC1 8 : 
 
 C H fOID / C 6 H 3 (OH) 2 CH : NOH 
 
 ^s^MvU^iJz \ rwM-rHri 
 
 -> C 6 H 3 (OH) 2 CH : NC 6 H 6 
 
 Behaviour. All the phenol-aldehydes show the same reactions of 
 the aldehyde group as the benzaldehydes. Oxidising agents convert 
 them with difficulty into phenol-carboxylic acids ; this is most easily 
 accomplished by fusion with caustic alkalies. They reduce an am- 
 moniacal silver solution, but not the Fehling solution. On oxidation 
 with dilute alkaline H 2 O 2 solution the o- and p-phenol-aldehydes split 
 off the aldehyde group and easily pass into pyro-catechin and hydro- 
 quinone (C. 1910, I. 634). They dissolve in alkalies, forming salts 
 e.g. C 6 H 4 (CHO).ONa ; the alkyl iodides convert the latter into alkyl 
 ethers. 
 
 (a) Monoxy-benzaldehydes HO.C 6 H 4 .CHO. Three are possible 
 according to theory ; all of them are known. Anisic aldehyde, the 
 VOL. II. Y 
 
322 ORGANIC CHEMISTRY 
 
 methyl ether of p-oxy-benzaldehyde, has been known for the longest 
 period. 
 
 Salicylic aldehyde, o-oxy-benzaldehyde, formerly called salicylous 
 or spiroylous acid, boils at 196. Its sp. gravity equals 1-172 (15). 
 It occurs in the volatile oils of the different varieties of Spircea- e.g. 
 Spircea ulmaria. It is obtained by the oxidation of saligenin and salicin 
 (Piria, 1839) and by the decomposition of helicin, an oxidation product 
 of salicin (q.v.). Also by reduction of sodium salicylate with sodium 
 amalgam in the presence of free boric acid (B. 41, 4147, 4148). It is 
 most readily prepared (together with p-oxy-benzaldehyde) by the 
 action of chloroform and caustic potash upon phenol. It is separated 
 from the p-body by distillation in steam, in which salicylic aldehyde 
 is very volatile. It is rather easily soluble in water ; the solution is 
 coloured a deep violet by ferric chloride (compare saligenin and sali- 
 cylic acid). In alkalies it dissolves with an intense yellow coloration, 
 in contrast with p-oxy-benzaldehyde (B. 39, 3087)). Like all ortho- 
 oxy-aldehydes, it colours the skin an intense yellow. Sodium amalgam 
 transforms it into saligenin ; oxidising agents change it to salicylic 
 acid. 
 
 Potassium - salicylic aldehyde C 6 H 4 (OK)CHO-fH 2 O consists of 
 yellow plates. The methyl ether C 6 H 4 (O.CH 3 ).CHO melts at 35 and 
 boils at 238 ; the ethyl ether boils at 248. The aceto-derivative CH 3 . 
 CO.O.C 6 H 4 .CHO melts at 37 and boils at 253. Glucose derivative, 
 see Helicin. o-Aldehydo-phenoxy-acetic acid CO 2 H.CH 2 O[2]C 6 H 4 [i] 
 CHO, melting at 132, splits off water and becomes cumarilic acid 
 (q.v.). Salicyl-aldoxime melts at 57 ; cp. B. 22, 3320. o-Anisaldoxime 
 CH 3 O.[2]C 6 H 4 [i]CH : N(OH), m.p. 92 (B. 23, 2741) ; alsoobtained from 
 anisol, mercury fulminate, and hydrated A1C1 3 besides p-anisaldoxime 
 (B. 23, 2741 ; 36, 648). Salieyl-hydramide (C 7 H 6 O) 3 N 2 , m.p. 167 
 (C. 1899, II. 827 ; 1900, 1. 123). Salicyl-hydrazone HO.C 6 H 4 CH : NNH 2 , 
 m.p. 96. o-Oxy-benzalazin HOC 6 H 4 CH : N.N : CHC 6 H 4 OH, m.p. 213 
 (B. 31, 2806). Phenyl-hydrazone, m.p. 142, b.p. 28 234, decomposes 
 on distillation partly into aniline and salicylic acid nitrile C 6 H 4 (OH) 
 CN (B. 36, 580). Nitro-salicyl-aldehyde, see B. 22, 2339. 
 
 m-Oxy-benzaldehyde, m.p. 104, b.p. 240, results from the reduction 
 of m-oxy-benzoic acid with sodium amalgam (B. 14, 969) and from 
 m-nitro-benzaldehyde (B. 15, 2045). Its oxime melts at 87. Its 
 phenyl-hydrazone melts at 130 (B. 24, 826). See B. 18, 2572, for the 
 nitro-m-methoxy-benzaldehydes. 
 
 p-Oxy-benzaldehyde is formed from phenol, chloroform, and caustic 
 alkali, together with salicylic aldehyde. It melts at 116, and sub- 
 limes. Its aldoxime melts at 65 ; its hydrazone at 178. Consult 
 B. 29, 2302, 2355, for the haloid p-oxy-benzaldehydes. Its methyl 
 ether, readily accessible, is the so-called : 
 
 Anisic aldehyde, p-methoxy-benzaldehyde CH 3 O[4]C 6 H 4 [i]CHO, b.p. 
 248, with sp. gr. 1-128 (15). It results in oxidising anethol (q.v.), 
 present in various essential oils (anise, fennel, tarragon, etc.), with dilute 
 nitric acid or a chromic acid mixture (C. 1900, I. 255). 
 
 p-Anisaldoxime, m.p. 61, from anisol, mercury fulminate, and 
 hydrated A1C1 3 , besides o-anisaldoxime and p-anisic nitrile. p-Ethoxy- 
 benzaldoxime (C 2 H 5 O)[4]C 6 H 4 CH : NOH, obtained in two forms, melt- 
 ing at 118 and 157 respectively, from phenetol, mercury fulminate, 
 
MONOXY-BENZALDEHYDES 323 
 
 and A1C1 3 (B. 36, 648, 650). Anisal chloride CH 3 O.C 6 H 4 .CHC1 2 , m.p. 
 20 (B. 41, 2331). 
 
 Homologous monoxy-benzaldehydes have been prepared from 
 various phenols by Reimer's method, and also by Gattermann's 
 method : 
 
 M.p. B.p. 
 
 o-Homo-salicyl-aldehyde . CH 3 [3]C e H 3 [2]OH[i]CHO . . 17 208 * 
 a-m-Homo-salicyl-aldehyde . CH 3 [ 4 ]C 6 H 3 [2]OH[i]CHO . . 59 220 2 
 /3-m-Homo-salicyl-aldehyde . CH 3 [6]C 6 H 3 [2]OH[i]CHO . . 31 229 2 
 p-Homo-salicyl-aldehyde . CH 3 [ 5 ]C 6 H 3 [2]OH[i]CHO . . 56 217 
 o-Homo-p-oxy-benzaldehyde . CH 3 [ 5 ]C 6 H 3 [ 4 ]OH[i]CHO . . 115 3 
 p-Homo-p-oxy-benzaldehyde . CH 3 [2]C 6 H 3 [ 4 ]OH[i]CHO . . 110 
 Trimethyl-salicyl-aldehyde . (CH 3 ) 3 [ 3 , 5, 6]C 6 H[ 2 ]OH[i]CHO. 105 
 p-Thymotin-aldehyde . . CH[2]C3H 7 [ 5 ]C 6 H 2 [ 4 ]OH[i]CHO 133 5 
 p-Carvacrotin-aldehyde . CH[ 5 ]C3H 7 [2]C 6 H 2 [ 4 ]OH[i]CHO liquid 
 P-Iso-butyl-salicyl-aldehyde . C 5 H u [ 4 ]C 6 H 3 [2]OH[i]CHO . 252.' 
 
 Literature. * B. 4,3667; 2 C. 1906, I. 1012; 5 B. 24,3667; 4 B. 18,2656; 
 32, 3598 ; 5 B. 16, 2097 ; 31, 1767 ; B. 19, 14 ; 7 B. 28, R. 4 68. 
 
 p-Oxy-mesitylene-aldehyde (CH 3 ) 2 [3,5](OH)[4]C 6 H 2 CHO,m.p. 114, 
 from mesitol by oxidation with ethyl nitrite; oxime, m.p. 169 (A. 311, 
 
 363). 
 
 The o-oxy-benzaldehydes are more readily soluble in water and 
 more sparingly soluble in chloroform than the p-oxy-benzaldehydes. 
 The o-bodies are volatile in steam, form sparingly soluble sodium 
 bisulphite derivatives, and are coloured yellow by ammonia (B. 11, 770). 
 
 The phenyl-hydrazones of homo-salicyl-aldehydes and other salicyl- 
 aldehydes with alkylated nucleus are, strangely enough, insoluble in 
 alkalies (B. 35, 4099). 
 
 p - Methoxy - phenyl - acetaldehyde CH 3 O[4]C 6 H 4 CH 2 CHO. The 
 oxime of this aldehyde is obtained by the reduction of anisylidene- 
 nitro-methane CH 3 OC 6 H 4 CH : CHNO 2 (C. 1902, II. 449). 
 
 p-Methoxy-hydratropa-aldehyde CH 3 O[4]C 6 H 4 CH(CH 3 )CHO, b.p. 
 256, from anethol CH 3 OC 6 H 4 CH : CHCH 3 by oxidation with HgO and 
 iodine, with migration of the aromatic residue (C. 1902, I. 1056). 
 
 (b) Dioxy-benzaldehydes. Some of the dioxy-benzaldehydes which 
 have been prepared by the chloroform-potash reaction are ethereal 
 derivatives of proto-catechuic aldehyde, and are characterised by an 
 agreeable odour. This is especially true of vanillin and piperonal, or 
 heliotropine. Both substances are prepared on a technical scale : 
 
 r[i]CHO /-[ijCHO r[i]CHO 
 
 C.H.] [ 3 ]OH C 9 H 3 ] [ 3 ]OCH 3 C 8 H 3 ] [3]O\ CH 
 
 ' [ 4 ]OH U4]OH U4]O/ 
 
 Proto-catechuic aldehyde Vanillin Piperonal. 
 
 Proto-catechuic aldehyde, [3, 4]-dioxy-benzaldehyde, m.p. 153 
 (B. 26, R. 701), was first obtained from piperonal (Fittig and Remsen, 
 1871) ; also from vanillin, iso-vanillin, and opianic acid by heating with 
 hydrochloric acid, and by the action of H 2 O 2 upon m- and p-oxy-benz- 
 aldehyde (C. 1904, II. 1631). It is prepared in the nuclear-synthetic 
 way from pyro-catechin by the chloroform reaction. It dissolves 
 readily in water. Ferric chloride colours its aqueous solution a deep 
 iqreen. It reduces ammoniacal silver solutions. Molten caustic potash 
 
324 ORGANIC CHEMISTRY 
 
 converts proto-catechuic aldehyde into proto-catechuic acid. Its 
 phenyl-hydrazone exists in two modifications : a- (stable), melting at 
 176, and )3- (unstable), melting at I2i-i28. Its oxime melts at 150 
 (B. 29, R. 670). Proto-catechuic-aldehyde-carboxylate (CO)O 2 : C 6 H 3 
 CHO, m.p. 124, b.p. 13 162. 
 
 Vanillin, m-methoxy-p-oxy-benzaldehyde, m.p. 80, sublimes readily, 
 and is the active constituent of the vanilla bean pod ( Vanilla plani- 
 folia), which contains about 2 per cent, of it (B. 9, 1287). Vanillin 
 also occurs in the orchid Nigritella suaveolens (B. 27, 3049). It was 
 first prepared artificially from the glucoside coniferine by its oxidation 
 with chromic acid (Tiemann and Haarmann, 1874 ; B. 7, 613). Gly co- 
 vanillin was obtained as an intermediate product in the oxidation 
 of coniferine ; acids or emulsin split it up into glucoses and vanillin 
 (B. 18, 1595, 1657). Vanillin is also produced by oxidising eugenol (q.v.) 
 (B. 9, 273). In the nuclear-synthetic way it has also been formed, 
 together with m-methoxyl-salicylic aldehyde, boiling at 266, from 
 guaiacol, chloroform, and caustic potash (B. 14, 2023 ; C. 1910, 1. 1881). 
 Industrially, it is obtained on a large scale by the oxidation of iso- 
 eugenol, obtained by the transposition of eugenol, contained in abund- 
 ance in carnation oil. It is advantageous to protect the free hydroxyl 
 from oxidation by the temporary introduction of an acid residue 
 (CH 3 CO, C 6 H 5 SO 2 , etc.) : 
 
 f [i]CH a .CH : CH 2 t [i]CH : CH.CH 3 t [ijCHO 
 
 C 6 H 3 | [ 3 ]OCH 3 > C 6 H 3 | [ 3 ]OCH 3 > C.EU [ 3 ]OCH 3 
 
 l[ 4 ]OH U4JOH U4JOH 
 
 Eugenol Iso-eugenol Vanillin. 
 
 Heated with HC1, vanillin splits up into proto-catechu-aldehyde 
 and CH 3 C. It behaves as a p-oxy-benzaldehyde and, when fused with 
 KHO, it passes into proto-catechuic acid two facts which determine 
 its constitution. By sodium amalgam, vanillin is converted into 
 vanillyl alcohol, and into hydra-vanilloiin, which corresponds to hydro- 
 benzoin. 
 
 Vanillin-oxime melts at 117 (B. 24, 3654). 
 
 Trithio-vanillin [C 6 H 3 (OH)(OCH 3 )CSH] 3 melts at 236 (B. 29, 143). 
 
 Iso-vanillin, p-methoxy-m-oxy-benzaldehyde, melting at 116, smells, 
 when heated, like vanilla and anise oil. It is obtained by oxidising 
 hesperitinic acid, or by heating opianic acid with hydrochloric acid. 
 
 Methyl-vanillin (CH 3 O) 2 C 6 H 3 CHO, m.p. 42, b.p. 283 (B. 11, 662). 
 
 Piperonal, proto-catechuic aldehyde-methylene ether, heliotr opine 
 (CH 2 O 2 )C 6 H 3 CHO, melting at 37 and boiling at 263, was obtained by 
 the oxidation of piperic acid (q.v.). It is also formed by treating 
 proto-catechuic aldehyde with alkali and methylene iodide. Industri- 
 ally, it is obtained from safrol (q.v.) as vanillin is obtained from eugenol. 
 Its odour is pleasant, like that of heliotrope. Piperonylic acid results 
 from its oxidation, and piperonyl alcohol from its reduction. On heat- 
 ing with dilute mineral acids to 190, under pressure, it breaks up into 
 proto-catechuic aldehyde and formaldehyde or methyl alcohol (C. 1905, 
 II. 1060). Its oxime melts at 110. Its phenyl-hydrazone melts at 100. 
 PC1 5 converts it into piperonal chloride (CH 2 O 2 )C 6 H 3 CHC1 2 , and di- 
 chloro-piperonal chloride (CC1 2 O 2 ).C C H 3 CHC1 2 , which is changed by cold 
 water into the carboxylate of proto-catechuic aldehyde chloride (CO)O 2 : 
 
DIOXY-BENZALDEHYDES 325 
 
 CeH 3 CHCl 2 , m.p. 97, b.p. 15 178, also obtained direct from piperonal 
 with thionyl chloride at 220, or by heating with chloride of sulphur 
 (B. 42, 417). Bromo-piperonal (CH 2 O 2 ).C 6 H 2 Br.CHO (B. 24, 2592). 
 o-Nitro-piperonal yields bidioxy-methylene indigo (B. 24, 617). 
 
 Homo-piperonal (CH 2 )O 2 : C 6 H 3 CH 2 CHO, m.p. 69, b.p. 10 144, 
 is formed by the oxidation of safrol (q.v.) with ozone (B. 41, 2751). Its 
 oxime, m.p. 120, is formed from piperonylidene-nitro-methane by 
 reduction with Al amalgam (C. 1902, II. 449). 
 
 Concerning nitro-proto-catechuic aldehyde, nitro-vanillin, ammo- 
 vanillin, and derivatives, see C. 1902, II. 31 ; B. 36, 2930. 
 
 The following bodies have been prepared from resorcin and hydro- 
 quinone by the action of chloroform and caustic alkali, just as proto- 
 catechuic aldehyde was made from pyro-catechin : 
 
 -Resorcyl-aldehyde (HO) 2 [2, 4]C 6 H 3 [i]CHO melts at 135. 
 Orcyl-aldehyde (HO) 2 [2 ,4]C 6 H 2 [5, i](CH 3 )CHO, m.p. 180, 
 
 from hydroquinone with chloroform and alkali. 
 Gentisin-aldehyde (HO) 2 [2, 5]C 6 H 3 [i]CHO melts at 99. 
 
 Dioxy-aldehydes are also produced in dilute solutions when much 
 chloroform and caustic potash are used. The monomethyl ethers of 
 resorcin and hydroquinone, like guaiacol, each yield, upon treatment 
 with chloroform and potash, two aldehydes : one, comparable in 
 deportment with salicyl-aldehyde, contains the aldehyde group in the 
 o-position with reference to phenol-hydroxyl ; while the other contains 
 the aldehyde group in the p-position, referred to the free phenol-hydro- 
 xyl (B. 14, 2024). 
 
 Gentisin-aldehyde is also produced by oxidation of salicyl-aldehyde 
 with potassium persulphate in alkaline solution (C. 1907, II. 901). The 
 anile of resorcyl-aldehyde C 6 H 2 [2, 4](OH) 2 CH : NC 6 H 5 , m.p. 126, is 
 also obtained from resorcin with formanilide and POC1 3 , and the oxime 
 C 6 H 3 (OH) 2 CH : NOH with mercury fulminate and HC1. 
 
 (c) Tri- and Tetra-oxy-benzaldehydes. From pyrogallol, phloro- 
 glucin, and oxy-hydroquinone the corresponding aldehydes have been 
 obtained with HCN and HC1 : Pyrogallol-aldehyde, gallic aldehyde 
 (HO) 3 [2, 3, 4]C 6 H 2 CHO, m.p. 161. Phloro-glucin-aldehyde (HO) 3 
 [2, 4, 6]C 6 H 2 .CHO, decomposed on melting. Oxy-hydroquinone-alde- 
 hyde (HO) 3 [2, 4, 5]C 6 H 2 .CHO, m.p. 223 (B. 32, 278). The oximes 
 and aniles of these aldehydes have also been obtained synthetically 
 by methods 3# and 36. Alky! ethers of these bodies have been formed 
 by oxidising aromatic plant derivatives, containing unsaturated ali- 
 phatic side chains (B. 16, 2112 ; 17, 1086 ; 24, 3818 ; 41, 1918). 
 
 Glyco-syringa-aldehyde, an oxidation product of syringine (q.v.), 
 when treated with emulsin yields 4-oxy-3, 5-dimethoxy-benzaldehyde, 
 syringa-aldehyde (B. 22, R. 107). 
 
 2, 4, 5-Trimethoxy-benzaldehyde, asaryl-aldehyde, m.p. 114, is 
 obtained by oxidising asarone (propenyl-trimethoxy-benzol) , and from 
 oxy-hydroquinone-trimethyl ether, with HCN, HC1, and A1C1 3 (B. 32, 
 289 ; 39, 1211). 
 
 (3) PHENOL KETONES. 
 
 They have been obtained (i) from amido-ketones (B. 18, 2691) ; 
 (2) from aromatic jS-ketone-carboxylic acids (B. 25, 1308) ; (3) by the 
 
326 ORGANIC CHEMISTRY 
 
 breaking up of C-alkylated benzo-tetronic acids with concentrated 
 alkalies (A. 379, 333) ; (4) from the dibromides of the propenyl-phenols 
 and their ethers : (a) by transforming into bromo-hydrins and ethylene 
 oxides, and transposing the latter with acids or by heating alone 
 (B. 38, 3464) : _ 
 
 CHBr.CHBrCHg _H,p CH(OH).CHBrCH 3 jcp_H in.O.tH.CHg _ CH 2 .CO.CH 3 
 C 6 H 4 OCH 3 ^C^OCHg ""'"C^OCHa " > C fl H 4 OCH 3 
 
 (b) by transforming into ethyl bromo-hydrins and a-ethoxy-propenyl- 
 phenols by sodium ethylate, and saponifying the latter : 
 
 CHBr.CHBrCH 3 C 2 H 8 ONa CH(OC 2 H 6 ).CHBr.CH 3 c a H t ONa 
 
 C 6 H 4 OCH 3 > C 6 H 4 OCH 3 
 
 C(OC 2 H 5 ) : CHCH 3 _ CO.CH 2 .CH 8 
 C e H 4 OCH 3 C 6 H 4 OCH 3 ' 
 
 To these must be added the methods of nuclear synthesis consist- 
 ing in the introduction of acid radicles into phenols, and phenol-alkyl 
 ethers ; (5) condensation of phenols with glacial acetic acid, and other 
 aliphatic acids, with the aid of zinc chloride or tin tetrachloride (B. 14, 
 1566 ; 23, R. 43 ; 24, R. 770), or, better, by phosphorus oxy-chloride 
 (B. 27, 1983) ; (6) from phenols with acid chlorides and, preferably, the 
 addition of zinc chloride (B. 22, R. 746 ; C. 1904, I. 1597) ; (7) from 
 phenol-alkyl ethers or phenols and acid chlorides in the presence of 
 A1C1 3 (B. 36, 3890 ; C. 1898, I. 1223) ; excess of A1C1 3 saponifies the 
 resulting phenol ethers to oxy-ketones. Starting from the thio-phenol 
 ethers, thio-phenol mono-ketones are obtained by this method (C. 1908, 
 
 II. 1659) 
 
 o-Oxy-aceto-phenone, b.p. 213, is formed by method 2. p-Oxy- 
 aceto-phenone, m.p. 107, is produced by method i. p-Aeetyl-anisol, 
 p-methoxy-aceto-phenone, m.p. 38 and b.p. 258, is formed by method 
 3. Propionyl-phenol HOC 6 H 4 COC 2 H 5 , m.p. 148, is produced by 
 method 4. 
 
 Aceto-pyro-eatechol (HO) 2 [3, 4]C 6 H 3 [i]CO.CH 3 , melts at 116 (B. 
 27, 1989). Aceto-vanillonHO[4](CH 3 O)[3]C 6 H 3 [i]COCH 3 , m.p. 115, 
 is produced in the oxidation of aceto-eugenol, and, synthetically, 
 from guaiacol by method 7, or by condensation of benzoyl-vanillin 
 with CH 3 MgI, oxidation, and rejection of the benzoyl group (B. 
 24, 2855, 2869). Aeeto-veratron (CH 3 O) 2 C 6 H 3 .CO.CH 3 , m.p. 48 
 (B. 27, 1989). Aeeto-piperone (CH 2 O 2 )[3, 4]C 6 H 3 [i]CO.CH 3 , m.p. 87, 
 results on oxidising proto-cotoin with potassium permanganate (B. 24, 
 2989 ; 25, 1127 ; 26, 2348). 
 
 Resaceto-phenone (HO) 2 [2, 4]C 6 H 3 [i]CO.CH 3 , m.p. 142, is pro- 
 duced by method 5, and from jS-methyl-umbelliferone upon fusion 
 with caustic potash (B. 16, 2123). Its p-methyl ether, paeonol CH 3 O[4] 
 (HO)[2]C 6 H 3 .CO.CH 3 , m.p. 45, occurs in the root-bark of Pceonia 
 Moutan, a ranunculus from Japan (B. 25, 1292). When resorcin- 
 diethyl ether is acetylated with the aid of aluminium chloride the 
 products are 1, 2, 4-resaeeto-phenone-diethyl ether, m.p. 69, and an 
 isomeric resaceto-phenone with the melting-point 178 (B. 29, R. 386). 
 Consult B. 29, R. 674, for haloid resaceto-phenones. 
 
 Orc-aeeto - phenone - dimethyl ether CH 3 [i]C 6 H 2 [3, 5](OCH 3 ) 2 [4] 
 
PHENOL-MONOCARBOXYLIC ACIDS 327 
 
 COCH 3 , m.p. 89, and isorc-aceto-phenone-dimethyl ether CH 3 [i]C 6 H 2 
 [3 5](OCH 3 ) 2 [2]COCH 3 , m.p. 48, from orcin-dimethyl ether by method 
 7 (B. 41, 793). 
 
 Quina-aceto-phenone (HO) 2 [2, 5]C 6 H 3 [i]CO.CH 3 , m.p. 202, is 
 produced by method 2. Valero-hydroquinone (HO) 2 [2, 5]C 6 H 3 .CO. 
 C 4 H 9 , m.p. 115. Its quin-hydrone results when sunlight acts upon 
 benzo-quinone and valeric aldehyde (B. 24, 1344). 
 
 Gall-aceto-phenone (HO) 3 [2, 3, 4]C 6 H 2 [i]CO.CH 3 , m.p. 168, is 
 formed by method 3 (B. 27, 2737 ; 43, 1016). 
 
 Anis-acetone, p-methoxy-phenyl-acetone CH 3 0[4]C 6 H 4 CH 2 COCH 3 , 
 b.p. 26i-265, is found in aniseed oil (?) (C. 1902, II. 1256). 
 
 o-Acetyl-thio-phenol HS[2]C 6 H 4 [i]COCH 3 , b.p. about 124, from 
 o-amido-aceto-phenone by way of the diazo-compound ; yields thio- 
 indigo during oxidation in alkaline solution, as well as the dithio- 
 compound. 
 
 (4) PHENOL-MONOCARBOXYLIC ACIDS. 
 
 The aromatic oxy-acids, containing hydroxyl united to the benzene 
 nucleus, combine the character of acids and phenols, hence are desig- 
 nated phenol acids. Should the hydroxyl groups enter the aliphatic 
 side chains, we would obtain aromatic alcohol acids, showing in their 
 behaviour very great similarity to the oxy-fatty acids. 
 
 Formation. A. From substituted carboxylic acids, as in the case of 
 the phenols : (i) Through the conversion of the amido-acids, by means 
 of nitrous acid, into diazo-compounds, and then boiling the latter with 
 water. (2) By fusing the sulpho-benzoic acids and halogen-benzoic 
 acids with alkalies. (3) By oxidation of the benzoic acids, in the form 
 of Am salts, with H 2 O 2 , o-, m-, and p-oxy-benzoic acids being formed 
 together (C. 1907, II. 2046). 
 
 B. From compounds in which the phenol-hydro xyl is already present : 
 (4) By fusing homologous phenols with alkalies, when the methyl group, 
 linked to the nucleus, will be oxidised to the carboxyl group. (5) By 
 oxidising the sulphuric or phosphoric acid esters of homologous phenols, 
 and then saponifying the resulting phenol-carboxylic esters. (6) By 
 fusing the phenol-aldehydes, difficult to oxidise, with alkalies. (7) By 
 converting the phenol-aldoximes into oxy-acid nitriles, and then 
 saponifying the latter. 
 
 C. Nuclear Synthesis. (8) By the action of carbon dioxide upon 
 the dry sodium salts of the phenols, at elevated temperatures, when 
 the carbonic acid generally enters the ortho-position with reference 
 to the hydroxyl group. This reaction will be more exhaustively dis- 
 cussed in connection with salicylic acid. 
 
 (9) By boiling the phenols with carbon tetrachloride and caustic 
 potash (B. 10, 2185) : 
 
 C 6 H 5 .OH+CC1 4 + 5 KOH = C 6 H 4 </** + 4 KC1+ 3 H 2 0. 
 
 Nl^L> 2 *- 
 
 The carboxyl usually occupies the p-position to the phenol-hydroxyl. 
 
 This reaction is perfectly analogous to that of the formation of 
 oxaldehydes by means of chloroform and caustic alkali. The action 
 of carbon tetrachloride upon p-alkylated phenols in the presence 
 of A1C1 3 yields derivatives in both cases of keto-dihydro-benzol 
 
328 ORGANIC CHEMISTRY 
 
 \ H H . o f rom w hi cn the phenols are regenerated on reduction 
 CC1 3 / H H 
 
 (B. 41, 897). 
 
 (10) When urea chloride, phenyl iso-cyanate, and phenyl-mustard 
 oil, together with aluminium chloride, act upon phenol ethers (or thio- 
 phenol ethers) in carbon disulphide solution (A. 244, 61 ; B. 27, 1733), 
 the products are amides, anilides, and thio-anilides of alkyl-oxy-acids. 
 
 Behaviour. They are monobasic acids. The hydrogen of the 
 carboxyl group is alone replaced by metals when they are acted upon 
 with alkaline carbonates. 
 
 Their hydroxyl hydrogen can also be replaced by alkalies, forming 
 
 basic salts e.g. C 8 H 4 < \r O ^ r Carbon dioxide, however, will convert 
 
 the latter into neutral salts. The ether esters manifest a like deport- 
 ment, inasmuch as it is only the alkyl ester which is eliminated, with 
 the production of a salt of an alkyl-ether acid : 
 
 /O.CH 3 /O.CHjj 
 
 C 6 H 4 < +KOH = C 6 H 4 < +CH 3 .OH. 
 
 X C0 2 .CH 3 X C0 2 K 
 
 The o-oxy-acids, unlike the m- and p-derivatives, volatilise in 
 aqueous vapour, are coloured violet by ferric chloride, and dissolve 
 in chloroform. The m-oxy-acids are coloured reddish brown when 
 heated with concentrated sulphuric acid, with the formation of oxy- 
 anthraquinones (B. 18, 2142). They are usually more stable than 
 the o- and p-acids. Boiling concentrated hydrochloric acid decom- 
 poses the p-acids into carbon dioxide and phenols. All the oxy-acids 
 decompose into carbon dioxide and phenols when distilled with lime. 
 
 A. Monoxy-monoearboxylie Acids. Salicylic acid or o-oxy-benzoic 
 acid is by far the most important representative of this class. It is 
 extensively applied both in therapeutics and in the colour industry. 
 
 Monoxy-benzoic Acids. The three isomerides theoretically possible 
 are known. 
 
 Salicylic acid, o-oxy-benzoic acid HO[2]C 6 H 4 [i]CO 2 H, melting at 
 155, occurs in a free condition in the buds of Spircza ulmaria, as the 
 methyl ester in oil of Gaultheria procumbens (oil of evergreen), a 
 species of Ericaceae. It is produced, by the general methods of forma- 
 tion, (i) from anthranilic acid; (2) from o-sulpho-,o-chloro-,and o-bromo- 
 benzoic acids ; (3) from o-cresol ; (4) from saligenin and salicyl-alde- 
 hyde ; (5) from phenolates with CO 2 ; and (6) with carbon tetrachloride. 
 
 It is also formed upon fusing cumarin (q.v.) and indigo (q.v.) with 
 caustic potash, and in the distillation of copper benzoate. 
 
 Technical Preparation. Two methods of bringing sodium phenolate 
 and CO 2 in reaction are applicable for this purpose : 
 
 (a) Sodium phenoxide is heated in a current of carbon dioxide at 
 i8o-220, when the latter is absorbed. Half of the phenol distils 
 over, and the residue consists of disodium salicylate (H. Kolbe) : 
 
 CO Na 
 2C 6 H 5 ONa+CO a = C 6 H 4 +C 6 H 5 OH. 
 
 The behaviour of potassium phenolate in this reaction is remark- 
 able. At 150 dipotassium salicylate is produced. At a more elevated 
 temperature, however, there is formed with the dipotassium salicylate 
 
MONOXY-MQNOCARBOXYLIC ACIDS 329 
 
 its isomeride, dipotassium para-oxy-benzoate. The latter is more 
 abundant in proportion to the increased temperature, until at 220 
 it is the sole product. The primary alkali salicylates, when heated, 
 show the following behaviour. 
 
 Monosodium salicylate at 220 yields disodium salicylate, phenol, 
 
 Primary potassium salicylate at 220 yields phenol, dipotassium 
 para-oxy-benzoate, and CO 2 . 
 
 Primary sodium para-oxy-benzoate at 280 yields phenol, CO 2 , 
 and disodium salicylate (/. pr. Ch. 2, 16, 425). 
 
 (b) Sodium phenoxide is saturated under pressure, in closed vessels, 
 with carbon dioxide, when it is converted into sodium pheno-carbonate 
 C 6 H 5 .O.CO 2 Na. This is transformed, under pressure, at a temperature of 
 I20-i3o, into phenol-sodium-o-carboxylic acid NaO[2]C 6 H 4 [i]COOH 
 (R.'.Schmitt, German patent 29,939) . This can be combined in one process 
 by letting CO 2 act, under pressure, upon sodium phenate at 120- 
 140 (German patent 38,742). The second method gives a complete 
 transformation of the phenol employed. This difference is probably 
 due to the fact that, in Kolbe's method, the phenol-sodium-o-carboxylic 
 acid first formed at the high temperature forms disodium salicylate 
 and free phenol with the sodium phenate (B. 38, 1375 ; 39, 14 ; 
 
 A. 351, 313). 
 
 History. Piria first obtained salicylic acid in 1838, when he 
 oxidised its aldehyde with molten caustic potash (A. 30, 165). In 
 1843 Cahours proved that evergreen oil consisted almost entirely of 
 methyl-salicylic ester (A. 53, 332). Gerland, in 1853, showed that 
 anthranilic acid, as suspected by A. W. Hofmann, could be converted 
 by nitrous acid into salicylic acid (A. 86, 147). In 1860 H. Kolbe 
 and Lautemann prepared it synthetically from phenol, sodium, and 
 carbonic acid (A. 115, 201). It was Kolbe who first correctly inter- 
 preted salicylic acid to be a monobasic oxy-acid, and, in 1874, dis- 
 covered' that the acid could readily be formed upon conducting carbon 
 dioxide over dry heated sodium phenate. It was in this way that he 
 ascertained the conditions necessary for the production of the acid 
 upon a commercial scale. 
 
 Properties and Behaviour. Salicylic 'acid crystallises from alcohol 
 in colourless prisms ; from hot water in long needles. It has a sweet 
 acid taste. It dissolves in 400 parts of water at 15, and in 12 parts at 
 100 ; it is very soluble in chloroform. When it is heated alone, salol, 
 or. phenyl-salicylic ester, and xanthone (q.v.) are produced (A. 269, 323). 
 Sodium in amyl-alcohol solution reduces it to normal pimelic acid. 
 In this reaction the ring is ruptured, and cyclo-hexanone-carboxylic 
 acid appears as an intermediate product (B. 27, 331)- 
 
 Its aqueous solution acquires a violet coloration upon the addition 
 of ferric chloride (C. 1908, II. 1511). It is a powerful antiseptic, arrests 
 decay and fermentation (Kolbe, /. pr. Ch. 2, 10, 9), and is applied 
 therapeutically both as the free acid and in the form of its sodium salt 
 (in rheumatoid arthritis). 
 
 Salicylates. Sodium salicylate HO.C 6 H 4 CO 2 Na is a crystalline 
 powder, with an unpleasant sweet taste. Basic calcium salicylate 
 
330 ORGANIC CHEMISTRY 
 
 (OC 6 H 4 CO 2 )Ca+H 2 O dissolves with great difficulty, and is precipi- 
 tated upon boiling salicylic acid with lime water. It serves for the 
 separation of salicylic acid from m- and p-oxy-benzoic acids. 
 
 Esters, Ethers, and Ether Esters. Methyl ester HO.C 6 H 4 .CO 2 CH 3 , 
 boiling at 224, with sp. gr. 1-197 (o), is the chief ingredient of ever- 
 green oil (from Gaultheria procumbens). It occurs in many different 
 plants in the form of a glucoside (B. 29, R. 511 ; C. 1899, II. 881). 
 
 When the methyl ester is digested with an alcoholic solution of 
 potassium hydroxide and methyl iodide, we get the dimethyl ester 
 
 C 8 H 4 .<^ co H , boiling at 245. Boiled with potassium hydroxide, 
 it is saponified, yielding methyl alcohol and methyl-salicylic acid 
 C 6 H 4 / 3 , melting at 98. It decomposes into carbon dioxide and 
 
 \\s\JnJLJi 
 
 anisol when heated to 200. 
 
 The chloride CH 3 O[2]C 6 H 4 COC1, b.p. 17 145, is obtained from the 
 acid with thionyl chloride (C. 1902, II. 216). 
 
 Phenol-salicylic ester, salol HO.C 6 H 4 .CO 2 .C 6 H 5 , melting at 43 and 
 boiling at 172 (12 mm.), results on heating salicylic acid alone to 200- 
 220, with the elimination of water and carbon dioxide ; from salicylic 
 acid, phenol, and POC1 3 ; from poly-salicylide on heating with phenol, 
 or when phosgene acts upon the sodium salts of salicylic acid and 
 phenol. It is applied as an antiseptic. It changes to xanthone, or 
 diphenylene-ketone oxide, when it is heated. When sodium salol 
 C 6 H 4 (ONa).CO 2 .CH 2 H 5 (from salol and sodium) is heated to 28o-3OO, 
 it changes to the isomeric sodium salt of phenyl-salicylie acid C 6 H 4 
 (O.C 6 H 5 ).CO 2 H, which melts at 113, and is not coloured by ferric 
 chloride. This acid is also obtained by heating o-chloro-benzoic acid 
 with alkaline phenolates, in the presence of copper (B. 38, 2111). 
 Phenyl-salicylic-aeid-phenyl ester C 6 H 5 O[2]C 6 H 4 [i]COOC 6 H 5 , m.p. 100, 
 is formed by heating phenyl-carboxylate (C 6 H 5 0) 2 CO with sodium car- 
 boxylate, CO 2 , and phenol (C. 1903, I. 1362). 
 
 Aeetyl-salieylic acid CH 3 CO.O.C 6 H 4 COOH, m.p. 135, is used as an 
 anti-neuralgic, under the name aspirin. The anhydride, m.p. 85, is 
 formed from the acid with SOC1 2 or COC1 2 in pyridin solution (C. 1908, 
 II. 996). 
 
 Carbo-methoxy-salicylie acid CH 3 OCO.O[2]C 6 H 4 [i]COOH, m.p. 
 135 with decomposition, from salicylic acid, chloro-carbonic ester, and 
 dimethyl-aniline (B. 42, 218). 
 
 Salieyi-acetie acid C 6 H 4 (OCH 2 COOH)COOH, m.p. 190, is prepared by 
 oxidising aldehydo-phenoxy-acetic acid, and from the sodium salts of 
 several acid derivatives of salicylic acid with chloracetic ester and sub- 
 sequent saponincation. The esters of the acids are condensed by sodium 
 to keto-cumarane-carboxylic esters (B. 33, 1398 ; C. 1900, II. 461). 
 
 Salicyl chloride HO.C 6 H 4 COC1 is not known. It is true that PC1 5 
 acts very energetically upon salicylic acid, but the resulting phosphor- 
 oxy-chloride is transposed by the phenol-hydroxyl, with evolution of 
 hydrochloric acid : 
 
 C.H.{ g 
 and there results : 
 
MONOXY-MONOCARBOXYLIC ACIDS 331 
 
 o- Chloro-earbonyl-phenyl-ortho-phosphorie-acid dichloride, melting 
 at 1 68 (n mm.). If the PC1 5 continues to act, this compound will 
 exchange an oxygen atom for two chlorine atoms, and o-triehloro- 
 methyl-phenyl-ortho-phosphorie-acid dichloride (Cl 2 PO)O[2]C 6 H 4 [i] 
 CC1 3 , boiling at 178 (n mm.), will be formed. When this is heated 
 with PC1 5 in a sealed tube to 180, there results : 
 
 o-Chloro-benzo- trichloride Cl[2]C 6 H 4 [i]CCl 3 , melting at 30 and 
 boiling at 130 (n mm.) (A. 239, 314). m- and p-Oxy-benzoic acids, 
 as well as m- and p-cresotinic acids, behave similarly. 
 
 If, however, the hydrogen atom of the phenol-hydroxyl is replaced by 
 the carbo-methoxyl or acetyl group, then PC1 5 produces the chlorides : 
 
 Methyl-salicyl chloride CH 3 O[2]C 6 H 4 [i]COCl, boiling at 254; 
 acetyl-salieyl chloride CH 3 CO 2 [2]C 6 H 4 [i]COCl, melting at 43 and 
 boiling at 135 (12 mm.) ; also earbo-methoxy-salicylie chloride CH 3 
 OCOO[2]C 6 H 4 [i]COCl, b.p. io7-iio. 
 
 When halogen atoms, nitro-groups, or methyl groups are introduced 
 into salicylic acid, and then occupy the o-position with reference to 
 the phenol-hydroxyl, the latter will be protected by them from the 
 attack of the phosphorus oxy-chloride. Consequently, in the action 
 of PC1 5 free oxy-chlorides will be produced : 
 
 o-Cresotinic chloride HO[2]C (J H 3 [3]CH 3 [i]COCl, melting at 28; 
 3-ehloro-salicyl chloride, melting at 63 ; [3, 5]-dichloro-salicyl 
 chloride, melting at 79 ; and [3, 5]-dichloro-nitro-salieyl chloride, 
 melting at 70 (B. 30, 221) ; also the 3, 5-dibromo- and 3, 5-di-iodo- 
 chlorides (A. 346, 300). 
 
 The influence of substituents in the vicinity of the phenol-hydroxyl 
 group is manifested in other ways, as in that of the esterification of 
 [2, 6]-substituted benzoic acids with alcohol and hydrochloric acid. 
 
 Salicylo-phosphoric chloride c 6 H 4 ^^ o _>pci, melting at 30 and 
 
 boiling at 167 (i i mm.), is readily formed when PC1 3 acts upon salicylic 
 acid at 70 (A. 239, 301). All substituted salicylic acids react similarly 
 (B. 30, 221). 
 
 Salicylo-salieylie acid HO[2]C 6 H 4 [i]COO[2]C ? H 4 [i]COOH, m.p. 
 148, is formed by careful treatment of salicylic acid and its salts with 
 SOC1 2 , PC1 3 , COC1 2 , etc. It is used in medicine under the name 
 diplosal (C. 1909, II. 1285). 
 
 Salicylides. An intramolecular anhydride of salicylic acid of the 
 
 /CO 
 
 formula C 6 H 4 / | is unknown, but several polymers of this hypo- 
 thetical simplest salicylide have been prepared : 
 
 Di-salicylide C 6 H 4 <(^^)> C 6 H 4 , needles, m.p. 201, produced by con- 
 ducting phosgene into a pyridin solution of salicylic acid (B. 34, 2951). 
 O . C fi H, COO C fi H, CO 
 
 Tetra-salicylide | i , m.p. 260, and poly-salicylide 
 
 CO.C 6 H 4 O.CO.C 6 H 4 
 
 (CjJE^OjJj., m.p. 322-325, are produced when POC1 3 acts upon 
 salicylic acid in xylol solution. The two compounds are separated 
 by means of boiling chloroform, with which the tetra-salicylide forms 
 a compound, salicylide chloroform (C 7 H 4 O 2 ) 4 .2CHC1 3 , crystallising in 
 beautiful quadratic octahedra, which contain 33 per cent, of chloroform, 
 
332 ORGANIC CHEMISTRY 
 
 loosely combined as chloroform of crystallisation. This body has been 
 used technically in the preparation of pure chloroform (Anschiitz, 
 A. 273, 94). o-Cresotinic acid and the o-haloid-salicylic acids behave 
 similarly (B. 35, 3644). Concerning later molecular-weight determina- 
 tions of tetra-salicylide, see A. 367, 164. 
 
 Salicyl-amide HO.C 6 H 4 .CONH 2 melts at 138 (B. 24, 138). If 
 phosgene is allowed to act upon a pyridin solution of salicyl-amide, 
 we obtain salicylic nitrile (see below) and earbonyl-salicyl-amide 
 
 C 6 H 4 / | m.p. 227, which is more easily obtained from chloro- 
 
 carbonic ester with salicyl-amide in pyridin (B. 35, 3647). The O-acyl- 
 salicylic amides are unstable, and, on fusing, or heating with pyridin, 
 they easily pass into the isomeric N-acyl compounds : 
 
 AcOC 6 H 4 CONH 2 > HOC 6 H 4 CONHAc. 
 
 Under certain conditions this migration of the acyl residue is 
 reversible (B. 40, 3506). Bromine and alkali transpose salicyl-amide 
 into carbonyl-amido-phenol, which is further brominated to dibromo- 
 carbonyl-amido-phenol (C. 1900, I. 255). 
 
 Salicyl-anilide C 6 H 4 (OH)CONHC 6 H 5 changes, when heated in dry 
 
 condition, to acridone C.H 4 <^^>C 6 H 4 . It is very probable that 
 
 it is at first rearranged into phenyl-anthranilic acid (B. 29, 1189). 
 Salicylo-nitrile HO.C 6 H 4 .CN, m.p. 98, is obtained from salicyl-aldoxime 
 and acetic anhydride (B. 26, 2621 ; 27, R. 134 ; 31, 3087). 
 
 Salicylic-acid hydrazide HO.C 6 H 4 CONH.NH 2 , m.p. 147, gives with 
 HNO 2 salicylic-acid azide HO.C 6 H 4 .CON 3 , m.p. 27, crystals of a pene- 
 trating odour. Salieyl-uric acid HO.C 6 H 4 CO.NHCH 2 COOH, m.p. 170, 
 occurs in urine after taking salicylic acid (A. 97, 250) ; synthetically, 
 it is prepared from salicylic-acid azide or carbo-methyoxy-salicylic-acid 
 chloride and glycocoll (B. 42, 219). 
 
 Thio-salicylic acid, and its derivatives, have lately acquired great 
 industrial importance on account of their easy conversion into indigoid 
 sulphur dyes ; see Thio-indigo, and A. 351, 390. 
 
 Thio-salicylie acid HS[2]C 6 H 4 [i]COOH, m.p. 164 (?), is formed 
 (i) from diazotised anthranilic acid by transposition with potassium 
 xanthogenate or sulpho-cyanate, or alkali polysulphides, and reduction 
 of the resulting compounds : CO 2 HC 6 H 4 S.C.SOC 2 H 5 , CO 2 HC 6 H 4 SCN, 
 (C0 2 HC 6 H 4 ) 2 S 2 ; (2) from chloro-benzoic acid by heating with alkaline 
 sulpho-hydrates or alkaline sulphides with addition of powdered copper 
 (German patent 189,200) ; (3) by reduction from the unstable o-sulpho- 
 benzoic dichloride. By oxidation, it is easily converted into dithio- 
 salicylic acid S 2 (C 6 H 4 COOH) 2 , m.p. 289 (B. 31, 1665). 
 
 Methyl-thio-salicylic acid CH 3 SC 6 H 4 COOH, m.p. 169, is formed 
 by the action of dimethyl sulphate or methyl iodide upon alkaline 
 solutions of thio-salicylic acid, di-thio-salicylic acid, o-rhodano-benzoic 
 acid, etc. On melting with alkalies, with addition of a condensing agent 
 like disodium cyanamide, sodium-lead, etc., it passes into thio-indoxyl 
 (German patent 200,200). 
 
 Aeetylene-bis-thio-salicylie acid CO 2 HC 6 H 4 S.CH : CH.SC 6 H 4 COOH, 
 formed by the action of acetylene dichloride upon the alkali salts of 
 thio-salicylic acid. With an acid condenser it gives thio-indigo. 
 
MONOXY-MONOCARBOXYLIC ACIDS 333 
 
 Phenyl-thio-glyeol-o-carboxylic acid HOCO[i]C 6 H 4 [2]S.CH 2 COOH, 
 m.p. 213, is obtained (i) from thio-salicylic acid and monochloracetic 
 acid ; (2) by the action of thio-glycollic acid upon o-diazo-benzoic acid. 
 Its nitrile, m.p. 140, is formed from o-amido-thio-phenol by transposi- 
 tion with monochloracetic acid, and replacement of the amido-group 
 by the cyanogen group, through the diazo-compound (A. 351, 412). 
 On heating with alkali, the phenyl-thio-glycol-o-carboxylic acid and 
 its nitrile pass into thio-indoxyl-carboxylic acid, which is easily con- 
 verted into thio-indigo by splitting off CO 2 and oxidation : 
 
 C0\_ CO \ 
 
 JCOOH (C(OH)^ 
 
 C ' H MS.CH,COOH " C H * IS - ^ C ' C 
 
 Phenyl - thio - salicylic acid C 6 H 5 SC 6 H 4 COOH, m.p. 167, from 
 o- chloro-benzoic acid, sodium thio-phenol, and copper. Gives thiox- 
 anthone on warming with concentrated H 2 SO 4 and acetic anhydride 
 (A. 263, 2 ; B. 37, 4526 ; C. 1905, I. 1394). Thio-salicylie-phenyl 
 ester HSC 6 H 4 CO 2 C 6 H 5 , m.p. 91, from thio-salicylic acid, phenol, and 
 POC1 3 (B. 42, 1134). 
 
 Diphenyl - sulphide - o, o - diearboxylic acid S(C 6 H 4 COOH) 2 , m.p. 
 230, by heating thio-salicylic acid with o-chloro-benzoic acid and 
 copper (B. 43, 588). 
 
 Substituted Salicylic Acids. The 5-derivatives of the mono-sub- 
 stitution products are the most readily prepared. 3-Derivatives are 
 formed simultaneously. Of the di-substituted salicylic acids, the 3, 5- 
 derivatives are most easily made. In them the substituents enter the 
 o p-position, referred to phenol-hydroxyl. 5-Chloro-, 5-bromo-, 5-iodo-, 
 and 5-nitro-salieylie acids melt at 172, 164, 196, and 228 respectively. 
 
 5-Nitroso-salieylic acid, m.p. 156 with decomposition, blue-green 
 crystals, from 5-nitroso-methyl-anthranilic acid on boiling with NaHO. 
 It may be regarded as possible quinone-oxime-carboxylic acid (B. 42, 
 2757). 
 
 3-Chloro-, 3-bromo-, 3-iodo-, and 3-nitro-salicylic acids melt at 
 178, 220, 193, and 144 respectively (B. 33, 3240). 
 
 3-Nitro-salicylic acid is prepared synthetically from nitro-malone- 
 aldehyde and aceto-acetic ester (C. 1900, II. 560). 
 
 3, 5-Diehloro-, 3, 5-dibromo-, 3, 5-di-iodo-, and 3, 5-dinitroso- 
 salicylic acids melt at 214, 223, 220-23O with decomposition, and 
 at 173 respectively. An anhydride, melting at 187 (B. 30, 223), has 
 been prepared by the action of the chloride of 3, 5-dichloro-salicylic 
 acid upon the silver salt (B. 30, 223 ; A. 346, 307). For other halogen- 
 substituted salicylic acids, see B. 38, 3294. 
 
 3-Amido-salieylic acid NH 2 [3]C 6 H 3 [2](OH)COOH, see /. pr. Ch. 2, 
 61, 532. 5-Amido-salicylie acid NH 2 [5]C 6 H 3 [ 2 ](OH)COOH is formed 
 by reduction of benzol-azo-salicylic acid C 6 H 5 N 2 C 6 H 3 (OH)COOH (C. 
 1906, II. 1058). 
 
 By diazotising, and successive combination with a-naphthyl-amine 
 and with a-naphthol-sulphonic acid, diamond black is obtained ; by 
 reduction of the diazo-compound, hydrazin-salieylic acid NH 2 NHC 6 H 3 
 (OH)COOH, m.p. 148 (B. 32, 81 ; C. 1900, I. 205). 5-Diethyl-glyeo- 
 coll - amido - salicylic methyl ester (C 2 H 5 ) 2 NCH 2 CO.NH.C 6 H 3 (OH) 
 COOCH 3 is recommended as a local anaesthetic, and called nirvanin. 
 Sulpho-salieylic acid (SO 3 H)C 6 H 3 (OH)COOH, and nitro-sulpho-salicylic 
 
334 ORGANIC CHEMISTRY 
 
 aeid, see B. 33, 3238 ; /. pr. Ch. 2, 61, 545. Amido-sulpho-salieylie acid 
 
 is formed from nitro-salicylic acid with Na bisulphite (C. 1901, II. 716). 
 
 m-Oxy-benzoic acid HO[i]C 6 H 4 [i]CO 2 H, m.p. 200, sublimes with- 
 out decomposition. p-Oxy-benzoie acid HO[4]C 6 H 4 [i]CO 2 H melts, 
 when anhydrous, at 210 with partial decomposition into carbon dioxide 
 and phenol. Its methyl ester melts at 131 and boils at 270-28o 
 (B. 27, R. 570). The two acids are obtained from their corresponding 
 amido- and haloid benzoic acids by methods I and 2. See above for 
 the production of p-oxy-benzoic acid, together with salicylic acid, by 
 methods 8 and 9. p-Oxy-benzoic acid is also obtained from many 
 resins by fusing them with caustic potash. For the behaviour of m- 
 and p-oxy-benzoic acids with PC1 5 , consult above. Compare A. 261, 
 236, for the action of chlorine upon the three oxy-benzoic acids. 
 
 m-Oxy-p-amido- and m-amido-p-oxy-benzoic methyl ester, m.p. 
 121 and in , are known as local anaesthetics, under the names 
 orthoform and new orthoform (A. 311, 26). 
 
 Anisic acid, p-methoxy-benzoic acid CH 3 O[4]C 6 H 4 [i]CO 2 H, m.p. 
 185 and b.p. 280, is, like benzoic and salicylic acids, one of the acids 
 which has been long known. It is isomeric with methyl-salicylic ester 
 and the other monomethyl derivatives of the oxy-benzoic acids in 
 general, as well as with the oxy-phenyl-acetic acids. Anisic acid is 
 easily obtained, hence numerous transposition products of it are known. 
 It is prepared by oxidising anethol, the chief ingredient of anise oil, and 
 other ethereal oils containing anethol (q.v.), with dilute nitric acid, or 
 with a chromic acid mixture. Synthetically, it is obtained from 
 p-bromo-anisol, Mg, and CO 2 (C. 1903, I. 636). 
 
 Nitrile, m.p. 60, b.p. 257, from p-nitro-benzo-nitrile with sodium 
 methylate. Also from anisamide with PC1 5 , and from anisol, BrCN, 
 and A1C1 3 (B. 33, 1056 ; 36, 648 ; C. 1900, 1. 130). 
 
 History. Cahours (1839) discovered anisic acid when he oxidised 
 anise oil (A. 41, 66). Kolbe at first considered it methoxy-benzoic acid, 
 because when it was distilled with caustic baryta it broke down into 
 CO 2 and anisol. Saytzew (1863) found that when anisic acid was 
 heated with hydriodic acid it yielded an acid different from salicylic 
 acid, yet isomeric with the latter (A. 127, 129). This was subsequently 
 found to be p-oxy-benzoic acid. In 1867 Ladenburg showed that 
 anisic acid could be prepared by saponifying the dimethyl ether ester 
 of p-oxy-benzoic acid (A. 141, 241). 
 
 Oxy-toluic Acids or Cresotinic Acids CH 3 .C 6 H 3 (OH).CO 2 H. The 
 ten possible isomerides are known (B. 16, 1966). They are isomeric 
 with the three oxy-methyl-benzoic acids, or benzyl-alcohol-carboxylic 
 acids, and phenyl-glycollic acid, or almond acid. They have been pre- 
 pared from the toluic acids by methods i and 2, from the oxy-aldehydes 
 by method 6, and from the cresols by methods 8 and 9. 
 
 Homo-salicylic acids : Methyl- m-oxy-benzoic acids : 
 
 CH 3 [3]C 6 H 3 [2, i](OH)COOH, m.p. 163. CH 3 [2]C 6 H 3 [3, i](OH)COOH, m.p. 183. 
 
 CH 3 [ 4 ]C 6 H 3 [2, i](OH)COOH, 177. CH 3 [ 4 ]C 6 H 3 [ 3 , i](OH)COOH, 206.' 
 
 CH 3 [ 5 ]C 6 H 3 [2, i](OH)COOH, 151. CH 3 [ 5 ]C 6 H 3 [ 3 , i](OH)COOH, 208. 
 
 CH 3 [6]C 6 H 3 [2, i](OH)COOH, 168. CH 3 [6]C 6 H 3 [3, i](OH)COOH, 184. 
 
 Methyl-p-oxy-benzoic acids : 
 CH 3 [2]C 6 H 3 [ 4 , i](OH)COOH, m.p. 177. CH 3 [3]C a H 3 [ 4 , i](OH)COOH, m.p. 172. 
 
MONOXY-MONOCARBOXYLIC ACIDS 335 
 
 Those isomerides, containing the hydroxyl group in the ortho-posi- 
 tion with reference to carboxyl, are coloured violet by ferric chloride, 
 just like salicylic acid. They dissolve easily in cold chloroform and are 
 volatile with steam. See above for their behaviour towards PC1 5 , PC1 3 , 
 POC1 3 , etc. 3-Methyl-homo-salicylic acid yields an o-homo-salicylic 
 or o-cresotide* chloroform (A. 273, 88) similar to salicylide chloroform. 
 5-Methyl-m-oxy-benzoic acid, prepared synthetically by the action of 
 baryta water upon acetone-oxalic ester (B. 22, 3271), yields by nitration 
 nitrococcic acid or 2, 4, 6-trinitro-m-oxy-m-toluic acid, melting at 180, 
 which is also formed when carminic acid, the dye of red cochineal, is 
 oxidised (B. 26, 2648). The 6-methyl-m-oxy-benzoic acid is best ob- 
 tained by heating /3-naphthol-6, 8-disulphonic acid with 50 per cent. 
 NaHO to 26o-28o (A. 350, 253). When the three isomeric creso- 
 tinic acids, or, better, their dibromo-substitution products, are reduced 
 with sodium and amyl alcohol, the ring is ruptured and a-, j8-, and 
 y-methyl-pimelic acids are produced (A. 295, 173). 
 
 o- and p-Oxy-mesitylenic acids HO.C 6 H 2 (CH 3 ) 2 CO 2 H melt at 179 
 and 223 (A. 206, 197; 311, 372). The former is obtained by nuclear 
 synthesis, through condensation of a-methyl-jS-ethyl-acrolein with 
 malonic ester, and treatment of the product with sodium alcoholate 
 (A. 358, 71) : 
 
 CH 3 CH 3 
 
 CH CH 2 . ROCO -H,0 CH C=COH 
 
 Similarly, we obtain from citral (q.v.) and malonic ester 3-iso- 
 amenyl-4-methyl-salicylic acid, m.p. 167. 
 
 The trimethyl-oxy-benzoic acids (B. 21, 884), as well as ethyl- 
 methyl-oxy-benzoie acids (A. 195, 284), are also known. The correspond- 
 ing iso-propyl-oxy-benzoic acids thymo- and iso-oxy-eumic acids, 
 melting at 142 and 94 (B. 19, 3307) result upon fusing carvacrol and 
 thymol with caustic potash. 
 
 Different isomeric p-methyl-iso-propyl-oxy-benzoic acids (CH 3 ) 
 (C 3 H 7 )C 6 H 2 (OH)COOH : thymotic and earva-erotinic acids have been 
 made by introducing the CO 2 group into thymol and carvacrol. See 
 B. 28, 2795, for the derivatives of thymotic acid. 
 
 The oxy-phenyl-fatty acids attach themselves to the alkyl-substituted 
 oxy-benzoic acids. They are produced (i) by diazotising the corre- 
 sponding amido-phenyl-fatty acids, and then decomposing the diazo- 
 derivatives with boiling water ; (2) by saponifying the oxy-benzyl 
 cyanides. 
 
 The o-oxy-acids, in which the phenol-hydroxyl group occupies the 
 y- or 8-position with reference to the carboxyl group, are, in contrast to 
 the corresponding o-amido-fatty acids, capable of existing, but when 
 heated they part with water and yield y- and S-lactones (Vol. I.). 
 
 The oxy-phenyl-aeetie acids HO.C ? H 4 .CH 2 .CO 2 H are isomeric with 
 the ten oxy-toluic acids (see these) , with the three oxy-methyl-benzoic 
 acids, and with the mandelic acids. o-Oxy-phenyl-acetic acid, bearing 
 close relationship to oxindol and isatin (q.v.), is also obtained from 
 o-oxy-mandelic acid by reduction with hydriodic acid. Ferric chloride 
 colours it violet. It passes into its lactone (see below) when it is 
 heated. p-Oxy-phcnyl-acetic acid occurs in urine, and arises from the 
 
33 6 ORGANIC CHEMISTRY 
 
 decomposition of albuminous bodies as well as in that of sinalbin, 
 occurring in the seeds of white mustard (B. 22, 2137). 
 
 o-, m-, and p-Oxy-phenyl-acetic acids melt at 137, 129, and 148. 
 m- and p-Oxy-phenyl-aeeto-nitrile melt at 52 and 69 (B. 22, 2139). 
 
 5, 2-Nitro-oxy-phenyl-acetic acid, m.p. 149, is obtained, syntheti- 
 cally, by condensation of nitro-malonic aldehyde and levulinic acid 
 (C. 1900, II. 560). 
 
 Oxy-phenyl-propionic acids. Four of the six theoretically possible 
 acids are known. 
 
 Phloretic acid, p - oxy - hydratropic acid HO[ 4 ]C.H 4 [i]CH<^; H . 
 
 melting at 129, is formed, together with phloro-glucin, when phloretin 
 (the phloro-glucin ester of phloretic acid) is digested with potassium 
 hydroxide. It has been prepared synthetically from p-amido-hydro- 
 cinnamic acid. Ferric chloride colours its solution green. Baryta 
 decomposes it into ethyl-phenol ; fusion with potassium hydroxide 
 produces para-oxy-benzoic acid. 
 
 Phloretin, monophloretic phloro-glucin ester (HO) 2 C 6 H 3 O.CO. 
 CH(CH 3 ).C 6 H 4 OH, melts at 254 (B. 27, 1631, 2686). See Phlorizin. 
 
 Hydro-cumarie acids or j3-phenol-propionie acids HO.C 6 H 4 .CH 2 . 
 CH 2 .CO 2 H result when the corresponding cumaric acids, the oxy- 
 cinnamic acids, or j3-oxy-phenyl-acrylic acids are reduced with sodium 
 amalgam. 
 
 o-Hydro-eumaric acid or melilotic acid, melting at 81, occurs free 
 and in combination with cumarin, the lactone of o-oxy-cinnamic acid, 
 in the yellow melilot (Melilotus officinalis). It is produced by the 
 action of sodium amalgam upon cumarin. Ferric chloride imparts a 
 bluish colour to the solution. When distilled, it passes into its lactone 
 hydro-cumarin. It yields salicylic acid when it is fused with caustic 
 potash. 
 
 m- and p-Hydro-eumaric acids melt at 111 and 128. p-Hydro- 
 cumaric acid is also produced in the decomposition of tyrosine. 
 
 y- and S-Lactones of o-oxy-phenyl-fatty acids are produced when 
 these acids are distilled. They correspond to the y- and 8-lactames 
 described above. 
 
 o-Oxy-phenyl-acetie acid lactone c 6 H 4 / [l]CH2tC T O melts at 49 
 
 l[2]0 1 
 
 and boils at 236 (B. 17, 975). 
 
 Hydro-cumarin, j3 - o - Oxy - phenyl - propionic acid lactone 
 
 C 6 H 4 { Cl]CH2 ' CH2( f , melts at 25 and boils at 272. When boiled with 
 
 water it regenerates the acid from which it was produced by 
 distillation. 
 
 B. Dioxy-monocarboxylic Acids are obtained by the same methods 
 which were used in the preparation of the aromatic monocarboxylic 
 acids. The car boxy 1 group is more readily introduced into the dioxy- 
 benzols than into the monoxy-benzols. This occurs upon heating the 
 bodies with a solution of ammonium or sodium carbonate to 100 or 
 130 (B. 18, 3202; 19, 2318; A. 351, 313). The dioxy-benzoic acids 
 break down, when heated, into carbon dioxide and dioxy-benzols. 
 
 Dioxy-benzoic Acids. The six possible isomerides are known. The 
 most important member of this class is : 
 
DIOXY-MONOCARBOXYLIC ACIDS 337 
 
 Proto - catechuic acid, 3, 4-dioxy-benzoic acid (HO) 2 [3, 4]C 6 H 3 
 [i]CO 2 H-j-H 2 O, in yellow needles, melts, when anhydrous, at 190, and 
 decomposes into pyro-catechin and carbonic acid. It occurs in the fruit 
 of Illicinm religiosum. It has been obtained from many tri-deriva- 
 tives of benzene, containing substituents in the 3, 4-position with 
 reference to a side chain, by fusing them with caustic potash e.g. from 
 the corresponding bromo- and iodo-p-oxy-benzoic acids, bromanisic 
 acid, p- and m-cresol-sulphonic acid, sulpho-p- and sulpho-m-oxy- 
 benzoic acids, from eugenol, piperic acid (compare also piperonylic 
 acid), etc., as well as from various resins (benzoin, asafcetida, myrrh, 
 and, particularly, kino) on fusion with potassium or sodium hydroxide. 
 The latter resin readily yields large quantities of the acid (A. 177, 188). 
 Compare further phloro-glucin ethers of pyro-catechuic acid. It is also 
 produced by the action of bromine upon quinic acid in aqueous solution. 
 
 The two possible pyro-catechuic monocarboxylic acids are produced 
 when pyro-catechin is heated to 140 with a solution of ammonium 
 carbonate. 
 
 Ferric chloride colours the solution green ; after the addition of a 
 very dilute soda solution it becomes blue, later red (all derivatives con- 
 taining the proto-catechuic residue (OH) 2 C 6 H 3 .C (B. 14, 958) react 
 similarly). Ferrous salts colour its salt-solutions violet. It reduces 
 an ammoniacal silver solution, but not an alkaline copper solution. 
 Diproto-eatechuie acid C 14 H 10 O 7 , is a tannic acid which results on boil- 
 ing proto-catechuic acid with aqueous arsenic acid. It is very similar 
 to common tannic acid, but is coloured green by ferric oxide. It forms 
 a compound with p-oxy-benzoic acid by the union of equimolecular 
 quantities (A. 134, 276 ;" 280, 18). 
 
 See Naphthalene ring formations for the conversion of substituted 
 proto-catechuic acids, by oxidation with nitric acid, into derivatives 
 of /?-naphtha-quinone. 
 
 The phenol ethers of proto-catechuic acid are : 
 
 f[i]C0 2 H f[i]C0 2 H f[i]CO,H f[i]C0 2 H 
 
 C 6 HJ[ 3 ]OCH 3 C 6 H 3 ][ 3 ]OH C 6 HJ [ 3 ]OCH 3 C 6 H 3 J [ 3 ]O\ QH 
 
 [ 4 ]OH lC4]OCH 3 l[ 4 ]OCH 3 l[ 4 ]0/ 
 
 Vanillic acid Iso-vanillic acid Veratric acid Piperonylic acid. 
 
 These alkyl-and alkylene-ether acids are formed when proto-catechuic 
 acid is treated with CH 3 I, CH 2 I 2 , and CH 2 Br.CH 2 Br and caustic potash, 
 as well as by oxidising the corresponding ethers of proto-catechuic 
 aldehyde. The proto-catechuic acid can be regained from them upon 
 heating with hydrochloric acid to 150, when the dimethyl-ether acid 
 will yield at first the two monomethyl-ether acids; whereas the 
 methylene ether, piperonylic acid, separates carbon in addition to 
 proto-catechuic acid : 
 
 C0 2 H.C 6 H 3 <()>CH 2 
 
 The alkyl-ether acids break down into carbon dioxide and alkyl- 
 pyro-catechuic ethers when they are heated with lime or baryta. 
 
 Vanillic acid, m-methyl-proto-cateckuic acid, melting at 211, sublimes. 
 It is obtained by the energetic oxidation of its aldehyde, vanillin, also 
 from coniferin, as well as by the decomposition of aceto-vanillic acid, 
 VOL. II. Z 
 
338 ORGANIC CHEMISTRY 
 
 melting at 142, the oxidation product of aceto-eugenol, aceto-ferulic 
 acid, and aceto-homo-vanillic acid, when they are treated with potassium 
 permanganate. Its nitrite melts at 87 (B. 24, 3654). 
 
 Iso-vanillie acid, p-methyl-proto-catechuic acid, melts at 250, and was 
 first obtained from hemi-pinic acid (see this), or 4, 5-dimethoxy-o- 
 phthalic acid upon heating with hydrochloric acid. 
 
 Veratric acid, 3, ^-dimethoxy-benzoic acid, melting at 179-5, occurs, 
 together with veratrin (see the alkaloids), in the sabadilla seeds (from 
 Veratrum Sabadilla). 
 
 Diethyl-proto-catechuic acid melts at 149. 
 
 Piperonylie acid, methylene-proto-catechuic acid, melting at 228, is 
 also formed by oxidising a-homo-piperonylic acid, obtained from safrol, 
 as well as from piperonal and proto-catechuic acid (see this) . It breaks 
 down when heated with hydrochloric acid (see above). By the action 
 of PC1 5 , and subsequent treatment with cold water, it can be 
 converted into the carboxylate of proto-catechuic acid, and into the 
 latter itself by saponification (C. 1908, I. 1689). Its nitrite melts at 
 95 (B. 24, 3656). 
 
 Ethytene-proto-catechuic acid melts at 133. 
 
 The phtoro-gtucin ethers of proto-catechuic acid are probably certain 
 vegetable substances which, upon fusion with caustic potash, break 
 down into phloro-glucin and proto-catechuic acid. They are also 
 related to theflavones (q.v.) , belonging to the pyrone group. They are : 
 
 Luteolin C 15 H 10 O 6 (B. 29, R. 647, 848), occurs in Reseda tuteola and 
 crystallises in yellow needles. Ferric chloride colours it green. 
 
 Catechin, from catechu, and Maclurin or moringa tannic acid 
 C 13 H 10 O 6 -f H 2 O, from yellow wood, Morus tinctoria, are generally 
 included among the tannic acids. Proteaic acid C 9 H 10 4 appears to 
 be a homologue of proto-catechuic acid. It is present in Protea mellifera 
 (B. 29, R. 415). 
 
 Pyro - catechin - o - earboxylie acid, 2, 3-dioxy-benzoic acid (HO) 2 
 C 6 H 3 CO 2 H+2H 2 O, melts at 199 when anhydrous. It readily breaks 
 down into CO 2 and pyro-catechin, from which it is formed, together 
 with proto-catechuic acid, by the action of ammonium carbonate (A. 220, 
 116). It also results when 3-iodo-salicylic acid is fused with caustic 
 potash. 
 
 Resoreinol-monocarboxylie Acids. There are three. Sym. dioxy- 
 benzoic acid results on heating sym. disulpho-benzoic acid with caustic 
 potash, and the other two acids are produced when resorcinol is treated 
 with ammonium dicarbonate or potassium dicarbonate solution (B. 18, 
 1985; 13,2379). 
 
 The a-compound is not coloured by ferric chloride ; whereas the 
 /3-body is coloured a dark red, and the y-modification blue- violet, by 
 the same reagent. 
 
 a-Resorcylie acid, 3, $-dioxy-benzoic acid (HO) 2 C 6 H 3 CO 2 H-f 
 iJH 2 0, melts at 233. It yields anthrachrysone (q.v.) when it is 
 heated with sulphuric acid. 
 
 j8-Resorcylic acid, 2, 4-dioxy-benzoic acid-\-^H. 2 O, melts in the 
 anhydrous state at 213. See B. 28, R. 1051 ; 29, R. 30, for the ethers 
 and esters of the acid. 
 
 It is converted in glacial acetic acid solution by chlorine into 
 hexachloro-m-diketo-hexene (B. 25, 2687). The nitrite melts at 175. 
 
DIOXY-MONOCARBOXYLIC ACIDS 339 
 
 y-Resorcylie acid, 2, 6-dioxy-benzoic acid, melts at i48-i67, and 
 breaks down into CO 2 and resorcinol. 
 
 Gentisinic acid, hydroquinone-earboxylic acid, 2, 5-dioxy-benzoic 
 acid, melts at 200, and at 215 breaks down into carbon dioxide and 
 hydroquinone. It was first prepared from gentisin, a xanthone deriva- 
 tive, together with phloro-glucin, on fusing it with caustic potash. It 
 is obtained from 5-bromo-, 5-iodo- and 5-amido-salicylic acids ; also 
 from hydroquinone and from gentisinic aldehyde (B. 14, 1988). It is 
 most easily obtained by oxidation of salicylic acid with potassium 
 persulphate in alkaline solution (A. 340, 213). Ferric chloride colours 
 it a deep blue and is decomposed into CO 2 and quinone (B. 18, 3499). 
 
 The Dioxy-toluic Acids (HO) 2 C 6 H 2 (CH 3 )CO 2 H are isomeric with 
 the dioxy-phenyl-acetic acids. The most important of the known 
 acids of this class is orsellinic acid, 2, 6-dioxy-p-toluic acid, which 
 melts at 176 and breaks down into CO 2 and orcin. It is obtained 
 from orsellic acid upon boiling the latter with water, or from erythrin 
 with baryta water. It is coloured violet by ferric chloride. 
 
 Orsellic acid, diorsellinic acid or lecanoric acid C 16 H 14 O 7 , melting 
 at 153, is an ether-like anhydride of orsellinic acid (HO) 2 .C 6 H 2 (CH) 3 . 
 CO.OC 6 H 2 (OH)(CH 3 )CO 2 H (?). It is found in different mosses of the 
 varieties Roccella and Lecanora. Boiling water converts it into 
 orsellinic acid. 
 
 Erythrin C 20 H 22 O 10 +iJH 2 O, erythrinic acid, is an ether derivative 
 of diorsellinic acid and erythrite. It occurs in the lichen Roccella 
 fuciformis, which is applied in the manufacture of archil, and is extracted 
 from it by means of milk of lime. When it is boiled with water it 
 breaks up into orsellinic acid and 
 
 Piero-erythrin C 12 H 16 O 7 -f-H 2 O, which, boiled with baryta water, 
 yields erythrite, orcin, and carbon dioxide : 
 
 Erythrin C 20 H 22 10 +H 2 = (HO) 2 C 6 H 2 (CH 3 )CO 2 H+C ia H 16 O 7 
 
 C 12 H 16 7 +H 2 = (HO) 2 C,H 3 CH 3 +C0 2 +C 4 H 6 (OH) 4 Erythrite. 
 
 Everninie acid C 9 H 10 O 4 =(HO) 2 C6H(CH 3 ) 2 CO 2 H (?) is produced, 
 together with orsellinic acid, on boiling evernic acid (from Evernia 
 prunastris) with baryta. It melts at 157, and is coloured violet by 
 ferric chloride. 
 
 Dioxy-durylic acid, pseudo-cumene-hydroquinone-carboxylic acid 
 (HO) 2 [2, 5]C 6 [3, 4, 6](CH 3 ) 3 CO 2 H, melts at 210 when rapidly heated, 
 and results from the reduction of durylic acid quinone, pseudo-cumene* 
 quinone-carboxylic acid O 2 [2, 5]C 6 [3, 4, 6](CH 3 ) 3 CO 2 H, which decom- 
 poses at 130, and is obtained by the action of ferric chloride upon a 
 hydrochloric acid solution of diamido-phenylic acid (A. 237, n). 
 
 Dioxy-phenyl-fatty Acids. Certain dioxy-phenyl-acetic acids and 
 dioxy-phenyl-propionic acids in this group are interesting. 
 
 a-Homo-proto-eateehuic acid and its ether acids have their side 
 groups occupying the same positions as those of proto-catechuic acid 
 and its ether acids : 
 
 CH 2 .C0 2 H (i) CH 2 .C0 2 H (i) [i]CH a .CO,H 
 
 C 6 H 3 OH (3) C 8 H 3 o.CH 3 (3) C 8 H 3 [ 3 ]O\ rH 
 
 OH ( 4 ) [OH ( 4 ) l[4]o/ ' 
 
 a-Homo -proto-catechuic a-Homo-vanillic acid, a-Homo-piperonylic 
 
 acid, m.p. 127 m.p. 142 acid, m.p. 127. 
 
340 ORGANIC CHEMISTRY 
 
 The aceto-a-homo-vanillic acid and a-homopiperonylic acid result in 
 the moderated oxidation of aceto-eugenol (q.v.) and safrol (q.v.) with 
 KMnO 4 . The former melts at 140, and is converted by caustic soda 
 into a-homo-vanillic acid, which hydrochloric acid, at 180, changes to 
 a-homo-proto-catechuic acid (B. 10, 207 ; 24, 2882). 
 
 a-Homo-vanillic acid and a-homo-piperonylic acid have also been 
 obtained from the condensation products of vanillin and piperonal 
 with hippuric acid, by transformation into the corresponding pyro- 
 racemic acids and oxidation with H 2 O 2 (A. 370, 372). a-Homo-proto- 
 catechuic acid is best prepared from the cyano-hydrin of methyl- 
 vanillin by boiling with HI (B. 42, 2949). 
 
 Homo-veratric acid (CH 3 O) 2 [3, 4]C 6 H 3 [i]CH 2 COOH, m.p. 99. 
 
 2, 5-Dioxy-phenyl-aeetie acid, homo gentisinic acid, m.p. 147, is 
 found in human urine during alcaptonuria. It crystallises with 
 one molecule H 2 O, and has been synthesised from the corresponding 
 dimethoxy-phenyl-aceto-nitrile, and from 2, 5-dioxy-mandelic acid by 
 boiling with HI (C. 1907, II. 901). 
 
 Sym. dioxy-phenyl-acetie acid (H0) 2 [3, 5]C 6 H 3 [i]CH 2 .CO 2 H+H 2 O 
 melts at 54. 
 
 The tri ethyl ester, obtained from the dicarboxylic acid derived 
 from this acid, is produced by the condensation of acetone-dicarboxylic 
 ester with sodium. It melts at 98, and yields dioxy-phenyl-acetic acid 
 upon saponification. It yields orcin when its silver salt is heated. 
 
 Hydro-caffeie acid, or J3-3,4-dioxy-phenyl-propionic acid, corresponds, 
 like a-homo-proto-catechuic acid, in the same arrangement of the substi- 
 tuting groups, to proto-catechuic acid : 
 
 [i]CH s CHj,CO,H C [i]CH 2 CH a CO,H ( [i]CH,CH 2 CO 2 H 
 
 ,-i [ 3 ]OCH 8 C.HJ [ 3 ]OH 
 
 l[4]OCH, l[ 4 ]OH U4JOCH, U 4 ]O' 
 
 C,H,^[ 3 ]OCH, QH 8 U 3 ]OCH 3 C,H,^ [ 3 ]OH QH 3 
 
 Hydro-caffeic dimethyl- Hydro -ferulic acid, Hydro -iso-ferulic acid, Hydro-caffeic methylene- 
 
 ether acid, m.p. 96 m.p. 89 m.p. 164 ether acid, m.p. 81. 
 
 Hydro-caffeic acid itself, and its ether acids, are formed from the 
 corresponding [3, 4]-dioxy-cinnamic or caffeic acid, and their deriva- 
 tives ferulic and iso-ferulic acids by reduction with sodium amalgam 
 (B. 11, 650 ; 13, 758). The methylene-ether acid is also produced by 
 oxidising jS-hydro-piperic acid (q.v.) (B. 20, 421). Ferric chloride 
 colours hydro-caff eic acid the same as it does proto-catechuic acid. 
 
 Hydro-umbellie acid, /3-2, ^-dioxy-phenyl-propionic acid (HO) 2 
 [2, 4]C 6 H 3 .CH 2 .CH 2 .CO 2 H, decomposes at 110. It is obtained from 
 umbelliferone, the 8-lactone of [2, 4]-dioxy-cinnamic acid, by the action 
 of sodium amalgam. Ferric chloride colours it green. 
 
 Hydroquinone-propionic acid (HO) 2 [2, 5]C 6 H 3 CH 2 CH 2 CO 2 H ; its 
 lactone melts at 163 ; obtained by oxidation of o-hydro-cumaric 
 acid with potassium persulphate in alkaline solution (C. 1907, II. 
 901). 
 
 Trioxy-benzoie acids (HO) 3 C 6 H 2 CO 2 H. Three of the six possible 
 isomerides are known. The most important is 
 
 Gallic acid (HO) 3 [3,4,5]C 6 H 2 CO 2 H+H 2 O. It melts and decom- 
 poses about 220 into CO 2 and pyrogallol. It occurs, free, in tea, in 
 the fruit of Ccesalpina coriaria (Divi-divi), in mangoes, and in various 
 other plants. It is obtained from the ordinary tannic acid (tannin) 
 by boiling it with dilute acids. It is prepared artificially from bromo- 
 
DIOXY-MONOCARBOXYLIC ACIDS 341 
 
 o-m-dioxy-benzoic acid and bromo-proto-catechuic acid when fused 
 with potassium hydroxide. 
 
 Gallic acid crystallises in fine, silky needles. It dissolves with 
 difficulty in cold water, but readily in hot water, alcohol, and ether. 
 It has a faintly acid, astringent taste. It reduces both gold and silver 
 salts (hence its application in photography). Ferric chloride throws 
 down a blackish-blue precipitate in its solutions. 
 
 The solutions of its alkali salts absorb oxygen when exposed to the 
 air, and, in consequence, become brown in colour. 
 
 Rufigallic acid, a derivative of anthracene (q.v.), is obtained by 
 heating gallic acid with sulphuric acid. 
 
 Oxidising agents, such as arsenic acid and iodine, convert gallic 
 into ellagic acid, probably a dilactone of a hexaoxy-diphenyl-dicar- 
 
 boxylic acid '^2*' (M. 29, 263). It is easily obtained in the 
 
 \_) C/gXi( v_/ Jij 2'^-'^"' 
 
 oxidation of tannin with H 2 O 2 besides the so-called luteic acid, the 
 monolactone^'^*^^*, __, corresponding to ellagic acid. On dis- 
 
 O C 6 rl (vJ-tl) z (^(J 2 ti 
 
 tillation with zinc dust, ellagic acid yields fluorene (q.v.). 
 
 In alkaline solution gallic acid is converted into gallo flavin (q.v.), a 
 yellow dye of the xanthone group. Hydrochloric acid and potassium 
 chlorate decompose the acid into iso-trichloro-glyceric acid or trichloro- 
 pyro-racemic acid (Vol. I.). 
 
 Basic bismuth gallate (HO) 3 C 6 H 2 CO 2 Bi(OH) 2 , under the name 
 dermatol, is applied as an odourless drying antiseptic. 
 
 Basic bismuth oxy-iodide gallate (HO) 3 C 6 H 2 CO 2 Bi(OH)I is used as 
 a substitute for iodoform under the name of Airol. 
 
 Ethyl-gallic ester (HO) 3 C 6 H 2 CO 2 C 2 H 5 melts at 141 when anhydrous. 
 Trimethyl- and triethyl-gallie-ether acids (R'O) 3 C 6 H 2 CO 2 H melt at 
 168 and 112. The trimethyl-ether acid, heated with HC1, yields 
 3, 5-dimethyl-gallo-etheric acid HO[4](CH 3 O) 2 [3, 5]C 6 H 2 COOH, m.p. 
 202, identical with syringa acid and also obtained from sinapinic acid 
 or oxy-dimethoxy-cinnamic acid by oxidation. 4-Methyl-gallo-etheric 
 acid, m.p. 240, from gallic acid with dimethyl sulphate (B. 36, 
 215, 660). 
 
 Methylene-methyl-gallie-ether acid, myristicinic acid (CH 3 O)(CH 2 O 2 ). 
 C 6 H 2 C0 2 H melts at I30-I35 (B. 24, 3821) when it is anhydrous. 
 Triacetyl-gallie acid melts with decomposition at 170. Gallic-acid 
 anilide, gallanol, has been used in medicine. This is true also of 
 dibromo-gallic acid, or gallo-bromol, melting at 140. 
 
 Pyrogallol-earboxylic acid (HO) 3 [2, 3, 4] -C 6 H 2 CO 2 H-f-JH 2 O is 
 prepared by heating pyrogallol with potassium bicarbonate (B. 18, 
 3205). It decomposes at I95-20O, but sublimes without decom- 
 position in a current of carbon dioxide. Ferric chloride colours it 
 violet. Triethyl-pyrogallol-carboxylie acid C 6 H 2 (O.C 2 H5) 3 .CO 2 H melts 
 at 105. It results in the oxidation of triethyl-daphnetic acid (q.v.). 
 
 Phloro-glucin-earboxylie acid (HO) 3 [2, 4, 6]C 6 H 2 CO 2 H+H 2 O decom- 
 poses even at 100, also when boiled with water, into carbon dioxide 
 and phloro-glucin, from which it is obtained by boiling with a potassium 
 carbonate solution (B. 18, 1323) . For ethers of phloro-glucin-carboxylic 
 acid, see C. 1903, I. 966. 
 
 An oxy-hydroquinone-earboxylie acid (OH) 8 [i, 2, 4]C 6 H 2 COOH, m.p. 
 
342 ORGANIC CHEMISTRY 
 
 2i7-2i8 with decomposition, is formed from oxy-hydroquinone 
 on boiling with bicarbonate solution and passing CO 2 (B. 34, 2840). 
 
 Triethyl-oxy-hydroquinone-ether acid (C 2 H 5 O) 3 [2, 4, 5]C 6 H 2 CO 2 H, 
 m.p. 134, results upon treating a- or /3-aesculetine-triethyl-ether acid 
 with potassium permanganate (B. 16, 2113). Trimethyl-oxy-hydro- 
 quinone-ether acid, asaronic acid, m.p. 144, is formed by the oxidation 
 of the synthetic asaryl-aldehyde (B. 12, 290). 
 
 Iridic acid, a-homo-dimethyl-gallic-ether acid (CH 3 O) 2 (HO)[3, 4, 5] 
 C 6 H 2 CH 2 CO 2 H, m.p. 118, is produced, along with formic acid and 
 iretol, when irigenin is decomposed with baryta water (B. 26, 2015). 
 
 Trimethyl-homogallie acid, methyl-iridic acid (CH 3 O) 3 [3, 4, 5]C 6 H 2 . 
 CH 2 COOH, m.p. 120, is formed by the oxidation of elemicin (q.v.), 
 and, synthetically, from trimethyl-gallic aldehyde (B. 41, 3662). 
 
 Addendum : Tannic Acids. The tannins, or tannic acids, are sub- 
 stances widely disseminated in the vegetable kingdom. They are 
 soluble in water, possess an acid, astringent taste, are coloured dark 
 blue or green (ink) by ferrous salts, precipitate gelatine, and enter 
 into combination (leather) with animal hides. Hence they are 
 employed in the manufacture of leather, and for the preparation of 
 ink. They are precipitated from their aqueous solutions by neutral 
 acetate of lead. 
 
 Some tannic acids appear to be glucosides of gallic acid i.e. ethereal 
 compounds of the same with various sugars or of their dehydration 
 products. They decompose into gallic acid and grape sugar upon 
 boiling with dilute acids. Others contain phloro-glucin instead of 
 grape sugar. On fusing with KHO the tannic acids mostly form proto- 
 catechuic acid and phloro-glucin. For the constitution of the tannic 
 acids, still somewhat obscure, see C. 1899, I. 559. 
 
 Gallo-tannic acid, tannin, occurs in large quantity (upward of 50 
 per cent.), in gall-nuts (pathological concretions upon different oak 
 species, Quercus infectoria, produced by the sting of insects) ; it also 
 occurs in sumach (Rhus coriaria), in tea, and in other plants. 
 
 Tannin is best obtained from gall-nuts. The latter are finely 
 divided, and extracted with ether and alcohol. The solution separates 
 into two layers, the lower of which is aqueous, and contains tannin 
 chiefly, and this is obtained by evaporation. For further purification 
 the solution, in amyl alcohol and ether, is fractionally precipitated with 
 benzine (B. 31, 3169). 
 
 Pure tannic acid is a colourless, shining, amorphous mass, very 
 soluble in water, slightly in alcohol, and almost insoluble in ether. 
 Many salts e.g. sodium chloride precipitate it from its aqueous 
 solutions, and it can also be removed from the latter by shaking with 
 acetic ether. It reacts acid, and is coloured dark blue by ferric chloride 
 (ink) ; gelatine precipitates it. Quantitative methods of estimating 
 tannin are based on this behaviour. Ordinary tannin is optically 
 active, its coefficient of rotation being about +60, but it is not uniform, 
 since a more strongly marked constituent can be separated out, with a 
 coefficient of about 76. Tannin appears to consist of a mixture of 
 inactive digallic acid (HO) 3 C 6 H 2 CO.OC 6 H 2 (OH) 2 COOH and its reduc- 
 tion product, the optically active leuco-tannin (HO) 3 C 6 H 2 CH(OH). 
 OC 6 H 2 (OH) 2 COOH, but this is contradicted by the very slight electric 
 conductivity of tannin, and its apparently very high molecular weight 
 
TANNIC ACIDS 343 
 
 (B. 43, 628). Dilute acids and alkalies split it up neatly into gallic 
 acid, which is oxidised to ellagic acid and luteic acid by boiling in 
 H 2 O 2 . Distillation with zinc dust produces diphenyl-methane. 
 
 Digallic acid (see above) crystallises with 2H 2 O, melts anhydrous 
 at 268 to 270 with decomposition, and can be obtained from tannin 
 by way of the carbethoxy-derivative. The acid behaves like tannin 
 towards glue, FeQ 3 , hydrolysis, and oxidation with H 2 O 2 . Its penta- 
 acetate, m.p. 211 to 214, yields, on reduction with zinc dust and 
 glacial acetic acid, hexa-aeetyl-leueo-tannin, m.p. 154, which has also 
 been isolated from the acetylation products of tannin. 
 
 We must distinguish the digallic acid obtained from tannin from the 
 digallic acids C 14 H 10 O 9 obtained artificially from gallic acid with POC1 3 , 
 or arsenic acid. These were formerly believed to be identical with 
 tannin, but they are distinguished from the latter by their much 
 greater electrical conductivity and by their inability to become 
 coagulated with arsenic acid (B. 31, 3167). 
 
 The penta-acetate C 14 O 5 (C 2 H 3 O) 5 O 9 , heated to 210, decomposes 
 with formation of pyrogallol. 
 
 Gallyl-gallic acid C 14 H 10 O 9 , a keto-tannic acid, forms an oxime and 
 phenyl-hydrazone. See B. 22, R. 754 ; 23, R. 24. 
 
 The other tannic acids found in plants have been but little investi- 
 gated ; but we may mention 
 
 Kino-tannin, which constitutes the chief ingredient of kino, the 
 dried juice of Pterocarpus erinaceus and Coccoloba uvifera. Its solu- 
 tion is coloured green by ferric salts. It yields phloro-glucin on fusion 
 with potassium hydroxide. 
 
 Catechu-tannin occurs in catechin, the extract of Mimosa catechu. 
 Ferric salts colour it a dirty green. Catechin or catechinic acid C 21 H 20 O 9 
 +5H 2 O is also present in catechu. It crystallises in shining needles. 
 
 Moringa-tannin C 13 H 10 O 6 -(-H 2 O, Maclurin, is found in yellow wood 
 (Morus tinctoria), from which it may be extracted (along with morin) 
 with hot water. When the solution cools morin separates out ; 
 maclurin is precipitated from the concentrated liquid by hydrochloric 
 acid, in the form of a yellow crystalline powder, soluble in water and 
 alcohol. Ferric salts impart a greenish-black colour to its solutions. 
 When fused with caustic potash it yields proto-catechuic acid and 
 phloro-glucin. It forms pentacidyl derivatives (C. 1897, 466). 
 
 Morin C 13 H 8 O 6 -f 2H 2 O decomposes into phloro-glucin and resorcin. 
 Nitric acid oxidises it to jS-resorcylic acid. Consult B. 29, R. 646, for 
 its constitution. 
 
 The tannin of coffee C 30 H 18 O 16 occurs in coffee beans and Paraguay 
 tea. Gelatine does not precipitate its solutions. Ferric chloride gives 
 them a green colour. It decomposes into caffeiic acid and sugar when 
 boiled with potassium hydroxide. Proto-catechuic acid is produced 
 when it is fused with potassium hydroxide. 
 
 The tannin of oak is found in the bark (together with gallic acid, 
 ellagic acid, quercite). It has the formula C 19 H 16 O 10 , and is a red 
 powder, not very soluble in cold water, but more readily in acetic ether. 
 Ferric chloride colours its solution dark blue. Boiling, dilute sulphuric 
 acid converts it into the so-called oak-red (phlobaphene), C 38 H 26 O 17 (?). 
 
 The tannin found in the quinine barks is combined with the quinia- 
 alkaloids. It closely resembles ordinary tannic acid, but is coloured 
 
344 ORGANIC CHEMISTRY 
 
 green by ferric salts. When boiled with dilute acids it breaks up into 
 sugar and quina-red, an amorphous brown substance, yielding proto- 
 catechuic acid and acetic acid on fusion with potassium hydroxide. 
 
 (e) Polyhydric Aromatic Alcohols, in which only one Hydroxyl is 
 present in each Side Chain, and their Oxidation Products. 
 
 (i) Di- AND TRIHYDRIC AROMATIC ALCOHOLS. 
 
 Xylylene Alcohols C 6 H 4 (CH 2 OH) 2 . The three isomerides are 
 obtained from the three corresponding xylylene chlorides or bromides 
 by boiling with a soda solution. The ortho- (i, 2), called phthalyl 
 alcohol, is obtained also from phthalic acid chloride by reduction in 
 glacial acetic acid with a large excess of sodium amalgam (B. 12, 646). 
 
 M.p. M.p. M.p. 
 
 1, 2-Phthalyl alcohol, 62 ; dichloride, 55 ; dibromide, 95. 
 
 1, 3-Xylylene alcohol, 46 ; dichloride, 34 ; dibromide, 77. 
 
 1, 4-Xylylene alcohol, 112 ; dichloride, 100 ; dibromide, 143. 
 
 The three chlorides are formed when the xylols are heated to 150 
 with PC1 5 (B. 19, R. 24). The bromides are produced when bromine 
 acts upon boiling xylols (B. 18, 1281), or upon the latter in sunlight 
 (B. 18, 1278). 
 
 o-Xylylene oxide, phthalane C 6 H 4 (CH 2 ) 2 O, b.p. 192, a colourless 
 oil, smelling intensely of oil of bitter almonds, is formed by heating 
 o-xylylene bromide with caustic alkali (B. 40, 965). 
 
 Tetrachloro-xylylene oxide C 6 C1 4 (CH 2 ) 2 O, m.p. 218 (A. 238, 331). 
 
 Xylylene sulpho-hydrates C 6 H 4 (CH 2 .SH) 2 , i, 2-, m.p. 46; i, 3-, oil, 
 boiling at 157 ; 1,4-, m.p. 47, from the xylylene bromides with alcoholic 
 KSH. The i, 2-xylylene sulpho-hydrate unites with aldehydes and 
 ketones with elimination of water to cyclic mercapfals and mercaptols 
 
 C 6 H 4 <^ c /C<( , from which cyclic sulphones are formed by oxidation 
 
 \ O / NXV 
 
 (B. 33, 729 ; 34, 1772 ; 35, 1388). 
 
 o-Xylylene sulphide C 6 H 4 (CH 2 ) 2 S, an oil smelling like mercaptan, 
 from o-xylylene bromide with concentrated K 2 S solution besides di- 
 xylylene disulphide [C 6 H 4 (CH 2 ) 2 S] 2 , m.p. 234, which is more easily 
 obtained from o-xylylene bromide and C 6 H 4 (CH 2 .SNa) 2 . Xylylene 
 sulphide gives by oxidation o-xylylene sulphone C 6 H 4 (CH 2 ) 2 SO 2 , m.p. 
 152, and its polymeride a disulphone [C 6 H 4 '(CH 2 ) 2 SO 2 ] 2 . Dixylylene 
 disulphide forms with Br a stable dibromide (C 6 H 4 (CH 2 ) 2 SBr) 2 , m.p. 
 in (B. 36, 18). 
 
 o-Xylylene-diamine CgH 4 [i, 2](CH 2 NH 2 ) 2 is a liquid. It results 
 when potassium phthalimide acts upon o-xylylene bromide (B. 21, 578), 
 as well as by the reduction of phthalazin. Upon heating, its chloride 
 yields : 
 
 o-Xylylenimine, dihydro-iso-indol C 6 H 4 (CH 2 ) 2 NH, boiling at 213, 
 
 also obtained by the reduction of chloro-phthalazin c.H 4 <f 9?? ; S, which 
 
 has given rise to a large number of derivatives (B. 33, 2808). 
 
 Xylylene bromide, treated with ammonia, gives bis-xylylene-am- 
 monium bromide C 6 H 4 (CH 2 ) 2 C 6 H 4 , which on further treatment with 
 ammonium passes into bis-xylylene-diamine [C 6 H 4 (CH 2 ) 2 NH] 2 , m.p. 80, 
 
DI- AND TRIHYDRIC AROMATIC ALCOHOLS 345 
 
 b.p. 12 I3O-I35. Xylylene bromide also reacts easily with primary, 
 secondary, and tertiary amines. Primary aliphatic or aromatic amines 
 mostly yield n-alkyl- or n-aryl-xylylene-imines ; but in aromatic amines, 
 containing substituents in ortho-position towards the NH 2 group, the 
 closing of the ring encounters steric hindrance, and di-aryl-xylylene-di- 
 amines are formed. Secondary amines mostly form cyclic xylylene- 
 ammonium bromides C 6 H 4 (CH 2 ) 2 N(RR 1 )Br, and tertiary amines form 
 xylylene-di-ammonium bromides ; their behaviour towards xylylene 
 bromide may be advantageously employed in testing alkaloids (B. 40, 
 852 ; C. 1899, 1.1246). 
 
 Like the tertiary amines, tri-ethyl phosphine combines with o-xyly- 
 lene bromide to form o-xylylene-di-triethyl-phosphonium bromide (B. 
 33, 606). m- and p-Xylylene bromide never yield cyclic derivatives 
 with amines, but derivatives of the corresponding diamines C 6 H 4 
 (CH 2 NH 2 ) 2 (B. 36, 1672). 
 
 Pseudo-cumenyl-glycol, CH 3 [i]C 6 H 3 [2, 4 ](CH 2 OH) 8 , melts at 77 (B. 19, 867). 
 Mesitylene-glycol, CH 3 [i]C 6 H 3 [3, 5](CH 2 OH) 2 , boils at 190 (20 mm.). 
 co 2 -Diamiao-mesitylene, CH 3 .C 8 H 3 (CH 2 NH 2 ) 2 , boils at 268 (B. 25, 3017). 
 
 Mesitylene-glycerin, mesicerine C 6 H 3 [i, 3, 5](CH 2 OH) 3 is a thick 
 liquid (B. 16, 2509). 
 
 o-Di-a-oxy-ethyl-benzol C 6 H 4 [i, 2][CH(OH)CH 3 ] 2 a yellow oil, from 
 o-phthalic aldehyde with CH 3 MgI ; on boiling with dilute HC1 it 
 passes into the corresponding oxide, 1, 3-dimethyl-phthalane C 6 H 4 
 [CH(CH 3 )] 2 0, b.p. 50 122 (B. 41, 986). 
 
 p-Di-a-ox-ethyl-benzol C 6 H 4 [CH(OH)CH 3 ] 2 , liquid, from p-diacetyl- 
 benzol (B. 27, 2527). 
 
 a, a-Dimethyl-, di-ethyl, and di-iso-propyl-o-xylyiene alcohol 
 HOCH 2 .C 8 H 4 CR 2 OH, m.p. 64, 82, and 108 respectively, are formed 
 by the action of alkyl-magnesium compounds upon phthalide. They 
 easily pass, by splitting off water, into the corresponding oxides, called 
 phthalanes (B. 40, 3060). 
 
 Oxy-m-xylenols are often formed, besides the univalent phenol 
 alcohols, by the action of formaldehyde and NaHO upon phenols 
 (B. 40, 2530) , e.g. 2, 6-dimethylol - p - eresol, oxy - mesitylene - glycol 
 HO[i]C 6 H 2 [ 4 ]CH 3 [2, 6](CH 2 OH) 2 , m.p. i30-5, from p-cresol (B. 42, 
 
 2539)- 
 
 As might have been expected, nine classes of oxidation products are 
 derivable from the bivalent aromatic alcohols with hydroxyls in two 
 side chains, as in the case of the aliphatic glycols. 
 
 (2) ALDEHYDE ALCOHOLS. 
 
 In this connection mention may be made of hydro-phthalide 
 C 6 H 4 <^ CH 2 / OH > t* 16 reduction product of phthalide. It is a syrup, 
 
 soluble in water. Dimethyl-hydro-phthalide CeH./^^^No, the 
 
 _ 
 
 reduction product of dimethyl-phthalide, melts at 89 (A. 248, 61). 
 
 Phenol-aldehyde alcohols are formed synthetically from phenol- 
 aldehydes, with formaldehyde and HC1. o-Oxy-aldehydo-p-benzyl 
 alcohol HO[i]CHO[2]C 6 H 3 [4]CH 2 OH, m.p. 108, from salicyl-aldehyde 
 (B. 34, 2455). 
 
346 ORGANIC CHEMISTRY 
 
 (3) AROMATIC DI-ALDEHYDES. 
 
 Phthalie Acid Aldehydes C 6 H 4 (CHO) 2 corresponding to the three 
 phthalic acids are obtained, like benzaldehyde from benzal chloride, 
 by heating the xylylol tetrachlorides with water or potassium oxalate. 
 They are also obtained in the form of their tetra-acetates C 6 H 4 [CH 
 (OCOCH 3 ) 2 ] 2 by the oxidation of the three xylols, dissolved in a mix- 
 ture of acetic anhydride and concentrated H 2 SO 4 , by means of chromic 
 acid. The o-phthalic aldehyde, treated with ammonia, and then 
 acidulated, gives a dark-violet coloration (A. 311, 353). 
 
 o-Xylylol tetrachloride, or, better, o-xylylol tetrabromide and 
 
 hydrazin, yield phthalazin C 6 H 4 /^ \ S ( B - 28 > l8 3)- 
 
 WUlrl '. JM 
 
 o-Phthalic aldehyde, m.p. 56 ; dioxime (see below). 
 Iso-phthalic aldehyde, ,, 89 ; dioxime, m.p. 180 (A. 347, 109). 
 Terephthalie aldehyde, 116 ; dioxime, ,, 200 (B. 16, 2995). 
 
 The o-, m-, and p-xylylol tetraehlorides C 6 H 4 (CHC1 2 ) 2 , corresponding 
 to the aldehydes, are prepared by heating the three xylols with PC1 5 to 
 I5o-i90. " 
 
 The o-body melts at 89 and boils at 273. The m-body boils at 
 273, and the p-compound melts at 93. 
 
 o-, m-, and p-Xylylene tetrabromide C 6 H 4 (CHBr 2 ) 2 , m.p. 116, 107, 
 and 169, from the three xylols by the action of bromine with heat 
 (A. 347, 107). 
 
 Hetero-ring formations of o-phthalic aldehyde : (i) With concen- 
 trated alkalies it forms phthalide; (2) with acetone and benzo-phenone 
 it condenses to fi-acetyl- and fi-benzoyl-hydrindone ; (3) with phenyl- 
 hydrazin chloride it forms phenyl-phthalazonium chloride ; (4) with 
 hydroxylamine it forms phthalimidoxime : 
 
 r f [i]CHO 
 
 CsH 4MCH - 
 
 CH,COCH, r ^j f v^j..L 2 \/~TJ mm / 2 ) 
 
 C,H S NHNH 
 
 i~> C 6 H 
 
 rCH=N 
 
 2NH,OH 
 
 Mesitylene-trialdehyde C 6 H 3 (CHO) 3 , m.p. 98 ; its hexa-acetate is 
 obtained from mesitylene with chromic acid and acetic anhydride 
 (C. 1908, I. 1623). 
 
 Oxy-dialdehydes are produced together with, and from, the oxy- 
 monaldehydes by means of Reimer's reaction. 
 
 Thymo-dialdehyde HO.C 6 H(CH 3 )(C 3 H 7 )(CHO) 2 melts at 79 (B. 16, 
 2104). 
 
 Resorcin-dialdehyde (HO) 2 .C 6 H 2 (CHO) 2 melts at 127 (B. 10, 2212). 
 
 a- and j3-0rcin-dialdehydes (HO) 2 C 6 H(CH 3 )(CHO) 2 melt at 118 
 and 168 (B. 12, 1003). 
 
 a- and -Oxy-iso-phthal-aldehyde (HO)[4]C 6 H 3 (CHO) 2 and HO[2] 
 C 6 H 3 (CHO) 2 melt at 108 and 88 (B. 15, 2022). 
 
ALCOHOL-CARBOXYL1C ACIDS 347 
 
 Oxy-uvitinic aldehyde HO(CH 3 )[i, 4]C 6 H 2 [2, 6](CHO) 2 , m.p. 133, 
 colourless needles, by oxidation of oxy-mesitylene-glycol (B. 42, 2545). 
 
 (4) Di- and Triketones. Only one acidyl group can be introduced 
 into benzene, even by means of the aluminium chloride synthesis. 
 
 p-Diaeetyl-benzol C 6 H 4 [i, 4](COCH 3 ) 2 , m.p. 114, is formed by the 
 action of dilute sulphuric acid upon terephthalyl-dimalonic ester 
 (B. 27, 2527). Diethyl-terephthalyl C 6 H 4 (COC 2 H5) 2 (B. 19, 1850). Tri- 
 acetyl-benzol C 6 H 3 [i, 3, 5](COCH 3 ) 3 , m.p. 163, is formed by the ben- 
 zene ring formation from formyl acetone. In the benzene homologues 
 containing methyl groups in the meta-positions it is an easy matter, 
 aided by A1 2 C1 6 , to introduce acetyl residues between every two such 
 methyl groups. Thus, mesitylene, durol, andiso-durol have given : 
 
 Diaeetyl-mesitylene C 6 H(CH 3 ) 3 (COCH 3 ) 2 , m.p. 46 and b.p. 310; 
 diacetyl-durol, m.p. 178 and b.p. 323-326, and diacetyl-iso-durol, 
 m.p. 121 and b.p 3i2-3i7 (B. 28, 3213 ; 29, 1413). 
 
 Diaeeto-resorcin (CH 3 CO) 2 [i, 5]C 6 H 2 [2, 4](OH) 2 , m.p. 183, from 
 resorcin, acetyl chloride, and ZnCl 2 (C. 1905, I. 814). 
 
 Triaeeto-phloro-gluein (CH 3 CO) 3 C 6 (OH) 3 , m.p. 156, is more prob- 
 ably to be regarded as a derivative of triketo-hexamethylene (B. 42, 
 2736). 
 
 (5) ALCOHOL-CARBOXYLIC ACIDS. 
 
 Oxy-methyl-benzoie Acids, Carbinol-benzoic Acids. There are three 
 possible isomerides, and all of them have been prepared. They are 
 isomeric with almond acid and the oxy-toluic acids. o-Oxy-methyl- 
 benzoic acid passes quite readily into the corresponding y-lactone, 
 phthalide. 
 
 Phthalide and meconin are the first lactones with which organic 
 chemistry was enriched. 
 
 o - Oxy - methyl - benzoic acid, benzyl - alcohol - o- carboxylic acid 
 
 C 6 H 4 /[ J ' * , melts at 120, loses water and becomes phthalide, from 
 
 v (_2jUri2Oxi 
 
 which it is obtained by dissolving in caustic alkali and then precipitat- 
 ing with mineral acids ; also from o-chloro-methyl-benzoic acid with 
 moist silver oxide. 
 
 Phthalide, o-oxy-methyl-benzoic acid lactone C 6 H 4 /|^ No, melt- 
 
 U [2jCH 2 / 
 
 ing at 83 and boiling at 290, was first made from o-phthalic acid. It 
 is formed (i) by heating o-oxy-methyl-benzoic acid or by allowing it to 
 stand in contact with water (B. 25, 524) ; (2) by the reduction of phtha- 
 lide chloride with zinc and hydrochloric acid (B. 10, 1445) ; (3) by the 
 reduction of phthalic anhydride in acetic acid solution with zinc dust 
 (B. 17, 2178) ; (4) by the action of bromine vapour upon ortho-toluic 
 acid at 130-! 40 ; (5) from xylylene dichloride upon boiling with 
 water and lead nitrate ; (6) by decomposing nitroso-phthalimidin ob- 
 tained from phthalimide with caustic potash (A. 247, 291) ; (7) by 
 treating o-cyano-benzyl chloride in glacial acetic acid with hydro- 
 chloric acid at 100 (B. 25, 3021) ; or (8) from phthalide-carboxylic 
 acid by heating (B. 31, 374). 
 
 It is reduced to ortho-toluic acid on boiling with hydriodic acid. 
 Potassium permanganate oxidises it to phthalic acid. See also Phthal- 
 aldehydic acid, Phthalic acid, and co-Cyan-o-toluic acid. Phenyl- 
 hydrazin adds itself to phthalide (B. 26, 1273 ; 33, 766). 
 
348 ORGANIC CHEMISTRY 
 
 Numerous derivatives have been obtained from o-oxy-methyl-ben- 
 zoic acid, some of which, like the acid itself, change over to heterocyclic 
 compounds. 
 
 o-Chloro-methyl-benzoic acid Cl.CH 2 [2]C 6 H 4 [i]COOH, m.p. 131, 
 form phthalide chloride with water, HC1 being liberated ; its ethyl 
 ester, b.p. 12 141, from phthalide chloride and alcohol (Anschiitz). 
 
 It boils at 141 (12 mm.), and also, without decomposition, at 245 
 (760 mm.). 
 
 o-Chloro-methyl-benzoyl chloride, phthalide chloride C1CH 2 [2]C 6 H 4 . 
 COO, boiling at 135 (12 mm.), results when PC1 5 acts upon phthalide 
 at 55-6o ; gives anthranol with benzene and A1C1 3 ( Anschiitz). 
 
 o-Chloro-methyl-benzamide C1CH 2 [2]C 6 H 4 .CONH 2 melts with de- 
 composition at 190 (see Pseudo-phthalimidine) . It is produced on 
 conducting dry ammonia into an ethereal solution of phthalide chloride, 
 and by the action of sulphuric acid upon its nitrile. 
 
 o-Chloro-methyl-benzanilide C1.CH 2 [2]C 6 H 4 CONHC 6 H 5 melts at 
 
 o-Chloro-methyl-benzo-nitrile, o-cyano-benzyl chloride C1.CH 2 [2] 
 C 6 H 4 CN, melting at 252, is formed upon conducting chlorine into boil- 
 ing o-tolu-nitrile (p. 286) (B. 20, 2222). The corresponding o-cyano- 
 benzyl alcohol is known only in its ethers (B. 25, 3018). 
 
 Phthalide yields the base phthalimidin C 6 H 4 /W \NH, when it 
 
 is heated in an atmosphere of ammonia. It can also be very readily 
 obtained by reducing phthalimide with tin and hydrochloric acid 
 (A. 247, 291) ; from o-cyano-benzyl-amine with HC1, and from phthalide 
 chloride by heating in a current of ammonia. It melts at 150 and 
 boils at 337. 
 
 Nitroso-phthalimidin C 8 H 6 ON.NO melts at 156. Pseudo-phthal- 
 
 is an oil. In contact with water it is 
 
 6 H 3 / f I . 
 
 L [2] 
 
 j]CH 2 >0 
 
 resolved into phthalide and ammonia. Its hydrochloride is formed 
 when o-chloro-methyl-benzamide is heated to i3o-i4O, also from 
 phthalide chloride with alcoholic ammonia. 
 
 Phthalide anile, phenyl-phthalimidin C 6 H 4 { W ^>NC 6 H 5) melting 
 
 at 160, results on heating phthalide and aniline to 2OO-22O, upon 
 reducing phthalanile with tin and hydrochloric acid, and by distilling 
 o-chloro-methyl-benzanilide under diminished pressure (Anschiitz). 
 o-Cyano-benzyl-amine NH 2 .CH 2 [2]C 6 H 4 CN is a colourless oil, which 
 becomes crystalline. It is formed when o-cyano-benzyl chloride acts 
 upon potassium phthalimide (B. 20, 2233 ', 31, 2738). 
 
 o-Diethyl-benzyl-amine-carboxylic acid (C 2 H 5 ) 2 NCH 2 C 6 H 4 COOH, 
 m.p. 105 (A. 300, 163). o-Cyano-benzyl-methylamine CNC 6 H 4 CH 2 . 
 NHCH 3 , m.p. 105; o-cyano-benzyl-aniline CNC 6 H 4 CH 2 .NHC 6 H 5 , 
 m.p. 125 (/. pr. Ch. 2, 80, 102). 
 
 Thio-phthalide C 6 H 4 /W^ / s melts at 60 (A. 257, 298), and 
 
 LljZJU-rlg 
 
 Seleno-phthalide ^^{r^cn X* 86 melts at 58 ( B - 24 2 59 6 ; 
 A 247, 299). 
 
 Thio - phthalimidin C t H^^!__ > Ss or o-cyano-benzyl-mercaptan 
 
ALCOHOL-CARBOXYLIC ACIDS 349 
 
 C 6 H 4 (CN)CH 2 SH, m.p. 62, from o-eyano-benzyl-rhodanide C 6 H 4 (CN) 
 CH 2 SCN, m.p. 86, with sulphuric acid, and from o-cyano-benzyl 
 chloride with potassium sulpho-hydrate. With excess of the latter we 
 
 obtain a dithio-phthalide C 6 H 4 /*\ S , m.p. 68, which easily 
 
 \Oo / 
 
 splits off SH 2 , and passes into a stilbene derivative (B. 31, 2646). 
 Phthalides, substituted in the benzene nucleus, are also known ; they 
 have been mostly obtained from substituted o-phthalic acids. Mention 
 may be made of : 
 
 p-Kitro-phthalide NO a C 8 H 3 (W<^ \o, m.p. 135. It is pro- 
 
 U[2jCH 2 / 
 
 duced when chromic acid and glacial acetic acid act upon o-nitro- 
 naphthalene (A. 202, 219). 
 
 p-Oxy-phthalide HO.C 6 H 3 /W^ a \o, m.p. 222 (A. 233, 235), 
 
 \i [ijGHg' 
 
 is obtained from p-oxy-o-phthalic acid. 
 
 Meconin, 5, 6-dimethoxy-phthalide (CH 3 O) 2 [5,6]C 8 H a ^W^ ^>O, m.p. 
 
 102, is the lactone of meconinic acid, which is only stable in the 
 form of its salts. Its name is derived from the Greek word /XTJKWV, 
 signifying poppy. 
 
 Meconin occurs already formed in opium, in which Couerbe dis- 
 covered it in 1832, and is obtained on boiling narcotin with water 
 (Wohler, and Liebig, 1832). It may be formed from opianic acid, 
 the corresponding aldehyde acid, just tike phthalide from phthal- 
 aldehydic acid, by reduction with sodium amalgam and precipitation 
 with acids. It was the first lactone known to chemistry : 
 
 Phthalide Phthalic aldehyde acid Meconin Opianic acid. 
 
 Synthetically, meconin has been prepared from the condensation 
 product of chloral with 2, 3-dimethoxy-benzoic ester, of dimethoxy- 
 
 trichloro-methyl-phthalide (CH 3 O) a c 8 H 3 <^~ "No. This yields, 
 
 \CH(CCl3)/ 
 
 with alkali, an acid which, on heating, yields meconin (A. 301, 
 359)- 
 
 i/r-Meconin, 3, 4-dimethoxy-phthalide (CH 3 O) a [ 3 , 
 
 m.p. 132. It is made from hemi-pinimide, just as phthalide is formed 
 from phthalimide (B. 20, 884). 
 
 o - a - Oxy - ethyl - benzoic acid lactone, a - methyl - phthalide 
 
 C 6 H 4 /y| CH /O> boils at 275. It is formed. in the reduction of aceto- 
 
 phenone-o-carboxylic acid with sodium amalgam, and by the action of 
 CH 3 MgI upon o-phthalic aldehyde acid (B. 38, 3981). Hydro-iodic acid 
 and phosphorus reduce it to o-ethyl-benzoic acid (B. 29, 2533). 
 
 a-Ethyl-phthalide, m.p. 12, b.p. 291, is obtained in a similar manner 
 (B. 32, 960). 
 
 Dimethyl-phthalide, o - j8 - oxy - iso - propyl - benzoie acid lactone 
 
 , m .p. 67 and b.p. 270, was made by the action of 
 
 zinc dust and methyl iodide upon phthalic anhydride (A. 248, 57). 
 
350 ORGANIC CHEMISTRY 
 
 Similarly, diethyl-, dipropyl-, and di-iso-propyl-phthalides have been 
 obtained, melting at 54, 76, and 84 respectively (C. 1909, II. 525). 
 
 o-j3-0xy-ethyl-proto-catechuic acid lactone C 6 H 2 (OH) 2 ( f '/, is 
 
 lL2jCl 2 .Crlj 
 
 closely related to several alkaloids such as corydalin, berberin, etc. 
 
 m-Oxy-methyl-benzoic acid is only known in the form of its alcohol 
 anhydride O[CH 2 [3]C 6 H 4 COOH] 2 , m.p. 180, which is formed from 
 m-cyano-benzyl chloride C1.CH 2 [3]C 6 H 4 CN, m.p. 67 and b.p. 259, 
 the reaction product of chlorine upon m-tolu-nitrile. co-Chloro-m- 
 toluic acid melts at 135, and m-benzyl-amine-carboxylic acid NH 2 CH 2 
 [3]C 6 H 4 CO 2 H melts at 216. m-Cyano-benzyl-amine NH 2 CH 2 [3] 
 C 6 H 4 CN, see B. 34, 3367. 
 
 p-Oxy-methyl-benzoie acid HO.CH 2 [4]C 6 H 4 CO 2 H, m.p. 181, is 
 obtained (i) from p-carbinol-bromide-benzoic acid Br CH 2 [4]C 6 H 4 . 
 CO 2 H (A. 162, 342) ; (2) by the action of concentrated sodium hydroxide 
 upon tereph thai-aldehyde (A. 231, 372). 
 
 p-Cyano-benzyl alcohol HOCH 2 [4]C 6 H 4 CN, m.p. 133, is prepared 
 from p-cyano-benzyl chloride, m.p. 79 and b.p. 263, by the action 
 of potassium carbonate. p-Chloro-methyl-benzamide CH 2 C1[4]C 6 H 4 
 CONH 2 , m.p. 173. p-Chloro-methyl-benzoic acid CH 2 C1[4]C 6 H 4 CO 2 H, 
 m.p. 199 (B. 24, 2416). 
 
 Benzyl-amine-p-carboxylic acid, yellow scales, and diethyl-benzyl- 
 amine-p-carboxylic acid, m.p. 150, see B. 23, 1060 ; A. 310, 207 ; 
 p-cyano-benzyl-amine, see B. 34, 3368. 
 
 p-Chloro-methyl-salieylie acid ClCH 2 [4]C 6 H 3 [i]OH[2]COOH, m.p. 
 163, from salicylic acid with formaldehyde and HC1 (C. 1901, I. 1394). 
 
 m- and p - Oxy - iso - propyl - benzoic acids (CH 3 ) 2 C(OH) .C 6 H 4 .CO 2 H, 
 melting at 123 and 155, result when m-cymol (A. 275, 159) and 
 p-cymol, from cumic acid, are oxidised with potassium permanganate. 
 The 3-amido-4-oxy-iso-propyl-benzoic acid, derived from the p-acid, 
 changes under the influence of carboxylic anhydrides into cumazonic 
 acids (q.v.). 
 
 (6) ALDEHYDE ACIDS. 
 
 o-Phthal-aldehydic acid and 5, 6-dimethoxy-o-phthal-aldehydic 
 acid, or opianic acid, are the most important representatives of this 
 class. In the ph thai-aldehyde acids the aldehyde group occupies the 
 y-position with reference to the carboxyl group. Like the aliphatic 
 y-ketonic acids (the laevulinic acids, Vol. I.), the ph thai-aldehyde acids 
 form monoacetyl derivatives, whose existence and deportment argue 
 more strongly for the y-oxy-lactone formula (Liebermann, B. 19, 765, 
 2288) than the carboxylic acid formula of such acids : 
 
 CH,C0 2 H or CH 2 .CO >0 ^wo^ M CtH ,( W C0 
 
 IMCHOH 
 
 Laevulinic acid o-Phthal-aldehydic acid. 
 
 Opianic acid forms two series of esters. Their difference is due to 
 the fact that the one series represents carboxylic esters, while the 
 other series consists of y-oxy-lactone esters. 
 
 The behaviour of the oxime anhydrides of phthal-aldehydic acid 
 and opianic acid is worthy of note. They change to the corresponding 
 
ALDEHYDE ACIDS 351 
 
 phthalimides with an appreciable evolution of heat, when they are 
 gently heated. The phthal-aldehydoxime-anhydridic acid first changes 
 to o-cyano-benzoic acid, which yields phthalimide upon fusion. The 
 determination of the heat of combustion of opian-oximic acid anhydride 
 and hemi-pinimide has shown that in the conversion of the former into 
 the latter the quantity of heat set free (52-6 Cal. for the gram-molecule) 
 was tenfold greater than the molecular rearrangement-energy of allo- 
 cinnamic into cinnamic acid, and eight times that observed in the 
 conversion of malei'c into fumaric acid (B. 25, 89). 
 
 o-Phthal-aldehydic acid (formulae above), melting at 97, is formed 
 (i) upon heating bromo-phthalide (see below) with water ; (2) by heat- 
 ing co-pentachlor-o-xylol, and (3) o-cyano-benzal chloride with hydro- 
 chloric acid (B. 30, 3197). Hydrazin converts the acid into phthal- 
 
 azone (q.v.) C 6 H 4 / [l]C ~ 1 j fH , melting at 183; phenyl-hydrazin 
 
 U[2]CH=N 
 
 changes it to phenyl-phthalazone, melting at 105 (B. 26, 531), and 
 hydroxylamine, in aqueous solution, into benzaldoxime-o-carboxylic 
 acid, melting at 120 ; while in alcoholic solution the product is benzal- 
 doxime-o-carbonic anhydride, benzo-ortho-oxazinone, melting at 145. 
 The latter at 145 rearranges itself with evolution of much heat into 
 o-cyano-benzoic acid, which at more elevated temperatures becomes 
 phthalimide (B. 26, 3264) : 
 
 C H r _*c H [I]CO H ->C H / [I]C \NH 
 
 C8H4 ^ C H -" C6H4 - >C8H41 
 
 Benzaldoxime-o-car- Benzaldoxime-o- o-Cyano-benzoic o-Phthalimide. 
 boxylic acid carboxylic acid acid 
 
 anhydride 
 
 With benzoyl-hydrazin and j3-phenyl-hydroxylamine also phthal- 
 aldehydic acid and opianic acid first form aldehyde derivatives (B. 
 34, 1017). 
 
 Methoxy-phthalide, phthal-aldehydic methyl ether, melting at 44 ; 
 ethoxy-phthalide, melting at 66 ; and amido-phthalide, amide of phthal- 
 aldehydic acid, are produced by the action of methyl and ethyl alcohol, 
 and of ammonia upon bromo-phthalide, or the bromide of phthal- 
 aldehydic acid, melting at 85, produced when bromine vapour acts 
 upon phthalide at 140. Aceto-phthal-aldehydic acid, acetoxy-phthalide, 
 is formed by the interaction of acetic anhydride and phthal-aldehydic 
 acid. 
 
 Diphthalide ether c 6 H 4 >o o q<c 6 H 4l melting at 221, 
 
 is formed from o-phthal-aldehydic acid and bromo-phthalide. In 
 accordance with the double formulation of phthal-aldehydic acid (see 
 above) two views may be held in regard to its various derivatives : 
 
 J [i]COOCH 3 f [i]CONH, / [i]COBr / [i]COOCOCH 3 
 
 ' H4 l[2]CHO L ' H4 t[ 2 ]CHO C ' H H[2]CHO C ' H H[ 2 ]CHO 
 
 Hi]co> i[i]co> r[i]co> |[i]co> 
 
 M[2]CH OCH, H *tt2]CH NH, C ' H4 \[ 2 ]CHBr Cf M [ 2 ] C H OCOCH, 
 
 Methoxy-phthalide Amido-phthalide Bromo-phthalide Acetoxy-phthalide. 
 
 The theory that acetoxy-phthalide and the diphthalide ethers are 
 anhydrides of carboxylic acids is very improbable. Phthal-aldehydic 
 acid and opianic acid react especially readily, even in the cold, with 
 
352 ORGANIC CHEMISTRY 
 
 amines. Water is eliminated. The resulting bodies dissolve in part 
 very easily in soda, and in part with difficulty, hence are in part derived 
 from the amido-phthalide and partly from the imido-aldehydic acid 
 formula (B. 29, 174, 2030). 
 
 ci]co>o rciicooH 
 
 [2JCH-NHR C H < \ [ 2 ]CH =NR. 
 
 r 
 
 \ 
 
 Phthal-aldehyde Chlorides. Pentaehloride of o-phthal-aldehydic acid, 
 
 n-pentachlor-o-xylol CHC1 2 [2]C 6 H CC1 3 , melting at 53, results when PC1 B 
 acts upon o-xylol at 140. o-Cyano-benzal chloride, nitrile of o-phthal- 
 aldehyde chloride acid, CHC1 2 [2]C 6 H 4 CN, boiling at 260, is formed 
 by the action of chlorine upon boiling o-cyano-toluol (B. 20, 3197). 
 
 Nor-opianic acid, 5, 6-dioxy-phthal-aldehydic acid (HO) 2 C 6 H 4 (CHO) 
 COOH, melting at 171, is obtained from opianic acid, together with 
 iso-vanillin and carbon dioxide, upon heating with hydriodic acid. It 
 is coloured bluish-green by ferric chloride. 
 
 Opianic acid, 5, 6-dimethoxy-phthal-aldehydic acid (CH 3 O) 2 [5, 6] 
 CgH 2 [2]CHO.CO 2 H, melting at 150, is produced on oxidising narcotin 
 with dilute sulphuric acid and MnQ 2 (1842, Wohler and Liebig, A. 44, 
 126). Meconin is formed in its reduction. When it is evaporated 
 with caustic potash it changes in part to meconin and partly to hemi- 
 pinic acid, just as benzaldehyde yields benzyl alcohol and benzoic 
 acid. It is oxidised to hemi-pinic acid. Upon heating with hydro- 
 chloric acid there results at first : 5-Methoxy-6-oxy-phthal-aldehydie 
 acid, methyl-nor-opianic acid (CH 3 O)[5](HO)[6]C 6 H 2 (CHO)CO 2 H, melt- 
 ing at 154 (B. 30, 691), while under more intense heat iso-vanillin 
 and CO 2 are the products. Concentrated sulphuric acid converts 
 opianic acid into rufiopin (q.v.), a tetra-oxy-anthraquinone derivative. 
 
 Opianic acid behaves toward hydrazin, phenyl-hydrazin, and 
 hydroxylamine just like phthal-aldehydic acid. Dimethoxy-phthal- 
 azone, opiazone, melts at 162, when it is anhydrous (B. 27, 1418). 
 Phenyl-opiazone melts at 175 (B. 19, 2518). Opianoximic acid, melt- 
 ing at 82, becomes, on boiling its aqueous solution, the anhydride of 
 opianoximic acid, melting at 114. When this is heated alone, or 
 when its alcoholic solution is boiled, hemi-pinimide results as a conse- 
 quence of rearrangement (B. 24, 3264). 
 
 Esters. Opianic acid forms two series of alkyl esters, corresponding 
 to the carboxylic and to the y-oxy-lactone formulas of the acid. The 
 one series, the true carboxylic esters, are stable in the presence of water. 
 They are formed by the action of alkyl iodides upon the silver salt or of 
 alcohols upon the chloride of opianic acid, and by esterifying opianic 
 acid with diazo-methane. 
 
 They manifest the typical aldehyde reactions (B. 29, R. 507). The 
 second series, the y-oxy-lactones or ^-esters, are formed on boiling 
 opianic acid with alcohols : Methyl- opianic ester (CH 3 O) 2 C 6 H 2 (CHO) 
 CO 2 CH 3 , melts at 82 and boils at 233 (51 mm.). The ethyl ester melts 
 
 at 64. i/r-Methyl-opianie ester (C^O)iC^\S^>9 m.p. 103, 
 
 and b.p. 238 (52 mm.). The 0-ethyl ester melts at 92 (B. 25, R. 907 ; 
 26, R. 700). 
 
 Acetyl-opianic acid melts at 120 (B. 19, 2288). [3]-Nitro-opianic 
 acid, m.p. 166, has an abnormally low affinity constant in aqueous 
 
KETONE-CARBOXYLIC ACIDS 353 
 
 solution, and therefore probably corresponds to the oxy-lactone from 
 (B. 36, 1541) ; methyl ester, m.p. 78 ; j/f-methyl ester, m.p. 182 (C. 1904, 
 
 I. 163). 
 
 It yields by reduction dimethoxy-anthranilo-carboxylic acid, azo- 
 
 opianie acid (CH 3 O) 2 C 6 H(COOH)/^~\o, which upon treatment with 
 acetone and sodium hydroxide condenses to acetonil-nitro-meeonin 
 (CH 3 0) 2 C 6 H(N0 2 ){( CH 2 CC CH 3)^>o, m.p. 175, and opian-indigo (B. 36, 
 
 2208). 
 
 Pseudo-opianie acid (CH 3 O) 2 [3, 4]C 6 H 2 [2](CHO)C0 2 H, m.p. 121, is 
 formed from berberal, an oxidation product of the alkaloid berberin 
 (q.v.), when it is boiled with dilute sulphuric acid. Amido-ethyl- 
 piperonyl-carboxylic anhydride (B. 24, R. 158) is formed simultaneously. 
 The oxime, melting at 124, is rearranged upon heating into hemipin- 
 imide (B. 24, 3266). 
 
 m-Aldehydo-benzoie acid, iso-phthal-aldehydic acid CHO[3]C 6 H^ 
 CO 2 H, melts at 165. m-Cyano-benzaldehyde melts at 80. m-Cyano- 
 benzal chloride boils at 274 (B. 24, 2416). p-Aldehydo-benzoic acid, 
 terephthal-aldehydie acid CHO[4]C 6 H 4 CO 2 H melts at 285. p-Cyano- 
 benzaldehyde melts at 97. p-Cyano-benzal chloride boils at 275 
 (B. 24, 2422). 
 
 Mono- and dioxy-aldehydo-acids have been obtained from mono- 
 and dioxy-carboxylic acids by means of chloroform and caustic alkali 
 (B. 12, 1334 ; 16, 2182). Similarly, anthranilic acid, with chloroform 
 and alkali, yields an aldehydo-o-amido-benzoic acid (C. 1900, I. 812). 
 
 (7) KETONE-CARBOXYLIC ACIDS. 
 
 o-Aceto-phenone-carboxylic acid is the most important of the 
 aromatic monocarboxylic acids with keto- and carboxyl-groups in 
 different side chains. In it the y-position imparts to the keto- 
 and carboxyl-groups reactions similar to those manifested by o-phthal- 
 aldehydic acid. Hence, in addition to the carboxylic acid formula 
 we must also consider the y-oxy-lactone formula for o-aceto-phenone- 
 carboxylic acid. Its acetyl compound must be viewed as acetyl- 
 y-oxy-lactone : 
 
 CH r[i]COOH CH /[i]CO>0 CH f[2]CO>0 
 
 4 \ [2]COCH 3 4 \ [ 2 ]C(OH)CH 3 4 \ [2]C(OCOCH 3 )CH 3 . 
 
 o-Aeeto-phenone-carboxylie acid, o-aceto-benzoic acid, m.p. 115, is 
 isomeric with benzoyl-acetic acid (q.v.) and tolyl-glyoxylic acid (q.v.). 
 It has a sweet taste, and is formed on boiling benzoyl-aceto-o-carboxylic 
 acid with water (B. 26, 705 ; 29, 2533). The acetyl compound melts 
 at 70 (B. 14, 921). Hydrazin converts it into methyl-phthalazone, 
 m.p. 220 and b.p. 247 (B. 26, 705). With phenyl-hydrazin it yields 
 methyl-n-phenyl-phthalazone, melting at 102 (B. 18, 803). Its ethyl 
 ester and hydroxylamine form an oxime anhydride, m.p. 158 (B. 
 16, 1995). 
 
 Various homologous o-acidyl-benzoic acids have been obtained by 
 
 digesting their anhydrides, the alkylidene-phthalides, with potassium 
 
 hydroxide. These anhydrides are produced in the condensation of 
 
 phthalic anhydride and fatty acids, when water and carbon dioxide 
 
 VOL. II. 2 A 
 
354 ORGANIC CHEMISTRY 
 
 are eliminated. o-Butyro-phenone-carboxylic acid and o-iso-valero- 
 phenone-carboxylie acid melt at 89 and 88 (B. 29, 1437 ; 32, 959). 
 
 p-Aceto-phenone-carboxylic acid melts at 200. It results from the 
 oxidation of p-j8-oxy-iso-propyl-benzoic acid (A. 219, 260). p-Cyan- 
 aceto-phenone, m.p. 60, is made from p-amido-aceto - phenone 
 (B. 20, 2955). 
 
 Methyl-benzyl-ketone-o-carboxylic acid COOH[2]C 6 H 4 CH 2 COCH 3 , 
 m.p. 119, is formed from methyl-iso-cumarin (q.v.) by boiling with 
 alkalies (B. 32, 965). 
 
 Benzyl-acetone-o-carboxylie acid COOH[2]C 6 H 4 [i]CH 2 .CH 2 .COCH 3 , 
 m.p. 114, see B. 40, 189. 
 
 Polycarboxylie Acids. Three varieties are to be distinguished in 
 each group of these acids : those in which all the carboxyl groups are 
 directly joined to the benzene nucleus ; those in which these groups 
 are in part joined to the nucleus and are in part present in the side 
 chains ; and, lastly, those in which all of the carboxyl groups are 
 contained in the side chains, e.g. : 
 
 c w /COOH r rcH 2 co 2 H r w /cH 2 co 2 H 
 
 Phthalic acids Homo-phthalic acids Phenylene-diacetic acids. 
 
 (8) DlCARBOXYLIC AdDS 
 
 (a) Phthalic acids are the final oxidation products of all benzene 
 derivatives in which two hydrogen atoms of the benzene nucleus have 
 been replaced by side chains. Hence they are of importance in deter- 
 mining the position of these two side groups in the benzene nucleus. 
 Their hydrogen addition products, the hydro-phthalic acids, are also 
 very important compounds from a theoretical standpoint. Again, 
 o-phthalic acid is distinguished from the m- and p-bodies by its ability 
 to form an anhydride and other cyclic derivatives. In addition to 
 the dicarboxyl formula, the y-dioxy-lactone formula has been taken 
 into consideration for this acid. It is applied technically in the manu- 
 facture of phthalein-dye substances, which are of great value. The 
 phthalic acids bear the same relation to the phthalyl alcohols, the 
 phthal-aldehydes, oxy-methyl-benzoic acids, and phthal-aldehydic 
 acids, that oxalic acid bears to ethylene-glycol, glyoxal, glycollic acid, 
 and glyoxalic acid : 
 
 CH 2 OH CHO COOH COOH COOH 
 
 CH 2 OH CHO CH 2 OH CHO COOH 
 
 Glycol Glyoxal Glycollic acid Glyoxalic acid Oxalic acid. 
 
 r TT /CH 2 OH r TT /CHO r M /COOH r w /COOH r /COOH 
 C MCHOH C6 C6l C ^ 
 
 Phthalyl- Phthal- Oxy-methyl- Phthal-aldehyde Phthalic 
 
 alcohols aldehydes benzoic acids acids. acids. 
 
 Phthalic acid, benzene - o - dicarboxylic acid C 6 H 4 /]^ 
 
 it 1 2jOvJ \~) xi 
 
 ( A - 269 I55 )' melts ' when ra P idl y heated, at 213, 
 
 decomposing at the same time into the anhydride and water. It is 
 obtained by oxidising naphthalene and tetrachloro-naphthalene with 
 nitric-acid permanganates (B. 36, 1805), or best with concentrated 
 
DICARBOXYLIC ACIDS 355 
 
 H 2 SO 4 and mercuric sulphate (German patent 91,202). It is manu- 
 factured on a large scale. It is formed from the naphthalene together 
 with benzoic acid on heating with NaHO and copper oxide to 240- 
 260 (C. 1903, I. 857). 
 
 It also results on oxidising o-xylol and o-toluic acid with potassium 
 permanganate, alizarin and purpurin with nitric acid, or with manganese 
 dioxide and sulphuric acid ; and, in slight amount, in the oxidation of 
 benzene and benzoic acid. It cannot be prepared by using chromic 
 acid as an oxidising agent, since the latter burns it at once to carbon 
 dioxide. It can be synthetically obtained from o-nitro-benzoic acid 
 by converting the latter into o-cyano-benzoic acid, and then boiling 
 this with alkalies. 
 
 History. Laurent first obtained the acid, in 1836, by oxidising 
 naphthalene tetrachloride. He considered it a naphthalene deriva- 
 tive, and named it naphthalinic acid (A. 19, 38). After Marignac had 
 deduced the correct formula, C 8 H 6 O 4 (A. 38, 13), and demonstrated 
 that the acid was not a derivative of naphthalene, Laurent gave it the 
 name phthalic acid (A. 41, 107). 
 
 When heated with excess of calcium hydroxide it yields benzene 
 and 2CO 2 . Only iCO 2 is split off, and calcium benzoate produced, if 
 its lime salt be heated to 33O-35o with one molecule of Ca(OH) 2 . 
 
 Sodium amalgam converts phthalic acid into di-, tetra-, and hexa- 
 hydrophthalic acids. 
 
 Esters. As the investigation of phthalyl chloride seemed to assign 
 a lactone formula to this body, in which the two chlorine atoms were 
 attached to the same carbon atom, search was made for two series of 
 esters. However, the action of alkyl iodides upon the silver salt, and 
 that of alcohols upon the chloride, produced the same esters (A. 238, 
 318). The methyl ester boils at 280 and the ethyl ester at 288 (B. 16, 
 860). These esters condense with acetic ester, acetone, and similar 
 bodies in the presence of sodium ethylate, forming diketo-hydrindene 
 derivatives. The phenyl ester melts at 70 (B. 7, 705 ; 28, 108). The 
 ethyl ester acid is a heavy oil. 
 
 Chlorides. The chloride of the ethyl-ester acid is a decomposable 
 oil, produced when PC1 3 acts upon the ethyl-ester acid (B. 20, ion). 
 
 Phthalyl chloride C^a Qr c.H 4 Wo. solidifies at <> 
 
 and boils at 275. It results upon heating the anhydride for several 
 hours with an equi-molecular quantity of PC1 5 at 200 (A. 238, 329). 
 The conversion of phthalyl chloride with glacial acetic acid and sodium 
 amalgam into o-phthalyl alcohol is an argument favouring the 
 sym. formula. The unsym. formula is evident from conversion of 
 the chloride by zinc and acetic acid into phthalide, diphthalyl 
 CH 4 ^>0 0<C\c 6 H 4 and hydro-diphthalyl, and with benzene 
 
 and aluminium chloride into phthalo-phenone or diphenyl-phthalide. 
 With lead thio-phenate, phthalyl chloride is converted into bi-thio- 
 
 phenyl-phthalide C 6 H 4 / c ( SC6H5)i ^>O, m.p. 85. This is oxidised by 
 
 permanganate to diphenyl-sulphone-phthalide, m.p. 194, which is 
 also formed direct from phthalyl chloride with sodium benzol 
 sulphonate (/. pr. Ch. 2, 66, 345). 
 
356 ORGANIC CHEMISTRY 
 
 Phthalylene Tetrachlorides. PC1 5 converts phthalyl chloride into 
 two phthalylene tetrachlorides, melting at 88 and 47. These cannot 
 be changed into one another. Their crystals have been measured. 
 Both yield phthalic acid, and have been assigned the formulas 
 
 C 6 H 4 |^ Q 3 andC 6 H 4 /CCl 2 \ The formation of the two chlorides is 
 
 UCOCl UC/O1.2/ 
 
 only comprehensible from the unsymmetrical phthalyl-chloride formula 
 (B. 19, 1188). The chloride, melting at 88, is also obtained in the 
 action of PC1 5 upon phthalide chloride. This reaction argues for the 
 unsymmetrical formula, just as well as the conversion into diphenyl- 
 an throne (see this) by condensation with benzene by means of A1 2 C1 6 
 or concentrated sulphuric acid (B. 28, R. 772). 
 
 Phthalic anhydride C 6 H 4 /WCO\ , melting at 128 and boiling at 
 ^L2jcu/ 
 
 284, sublimes readily in long needles. It results upon fusing phthalic 
 acid or digesting it with acetyl chloride (B. 10, 326). Phthalic anhy- 
 dride yields condensation products as readily as benzaldehyde. 
 
 Thus phthalyl-acetic acid is formed on boiling the anhydride ( with 
 acetic anhydride. It reacts in like manner with malonic ester and 
 aceto-acetic ester. At more elevated temperatures it combines with 
 homologous fatty acids, with the elimination of CO 2 and the formation 
 of alkylidene-phthalides. It condenses with phthalide to diphthalyl 
 (see this). With the phenols it yields the important phthalei'n dyes 
 (see these), a group of triphenyl-methane dyes, comprising certain 
 beautifully fluorescent compounds. Thio-phthalie anhydride C 6 H 4 
 (CO) 2 S melts at 114 and boils at 284 (B. 17, 1176). 
 
 Phthalo-mono-super acid (?) C 6 H 4 (COOH)COOOH, m.p. 110, with 
 conversion into phthalic acid, and peroxide-phthalie acid (COOH. 
 C 6 H 4 .CO) 2 O 2 , m.p. 156 with decomposition, are formed by shaking 
 up phthalyl anhydride with alkaline H 2 O 2 solution ; the former dis- 
 solves in water easily, the latter with difficulty. 
 
 Peroxide-phthalie acid diethyl ester O 2 (CO.C 6 H 4 COOC 2 H 5 ) 2 , m.p. 
 59, from ph thai-ethyl ester chloride with alkaline H 2 O 2 . 
 
 Phthalyl peroxide C 6 H 4 (CO 2 ) 2 melts at 133, giving gas evolution. 
 When heated rapidry to 136 it explodes. It is formed when phthalyl 
 chloride is acted upon with a sodium peroxide solution (B. 27, 1511). 
 
 Phthalamic acid or C 
 
 at 148, is formed from the anhydride and ammonia, or when baryta 
 water acts upon phthalimide (B. 19, 1402). Anilic acid melts at 192. 
 
 Phthalic diamide ^{gggj or C. Hl {M>o melts at 
 
 i4O-i6o, changing at the same time to phthalimide. It is pro- 
 duced when ammonia acts upon the ester (B. 19, 1399 ; 21, R. 612 ; 24, 
 R. 320 ; 25, R. 911). 
 
 Phthalimide c.H 4 {2>NH or C 6 H 4 {W^>o, melting at 
 
 238, is obtained : 
 
 By heating phthalic anhydride or chloride in ammonia gas ; 
 
 By heating phthalic acid with ammonium sulpho-cyanide (B. 19, 
 2283) ; from phthalamide, and 
 
 By the molecular rearrangement of the isomeric o-cyano-benzoic 
 acid. 
 
DICARBOXYLIC ACIDS 357 
 
 It forms potassium phthalimide C 6 H 4 (CO) 2 NK by the action of 
 alcoholic potash. 
 
 Salts of the heavy metals can be obtained from it by double decom- 
 position. Potassium phthalimide is readily rearranged, or transposed, 
 with organic halogen derivatives ; consequently it is frequently em- 
 ployed in the preparation of numerous amines. While by this means 
 alkylogens yield symmetrical alkylimides of the formula C 6 H 4 (CO)NR 
 e.g. sym. methyl- and benzyl-phthalimide, melting at 132 and 115, 
 
 unsymmetrical alkylimides of the formula C 6 H 4 / '( ^No are ob- 
 tained from the interaction of phthal-alkylamic acids and acetyl 
 chloride : unsym. methyl- and benzyl-phthalimide melt at 78 and 81 
 (B. 27, R. 737). 
 
 On brominating sym. methyl-phthalimide we obtain bromo-methyl- 
 phthalimide C 6 H 4 (CO) 2 NCH 2 Br, m.p. 150 ; on heating with water this 
 becomes oxy-methyl-phthalimide C 6 H 4 (CO) 2 N.CH 2 OH, m.p. 142, also 
 obtained from phthalimide with formaldehyde, at 100, and easily dis- 
 solved again into these constituents ; by condensation with benzols 
 by means of concentrated sulphuric acid, oxy-methyl-phthalimide is 
 converted into benzyl-phthalimides (C. 1902, II. 1164). From ethyl- 
 phthalimide with alkyl-magnesium haloids we get products of the 
 
 formula c eH 4 {[^^NC 2 H 5 (B. 37, 385). 
 
 On reduction, phthalimide becomes phthalimidin ; with bromine 
 and alkaline hydrate it becomes anthranilic acid. The bromyl-phthal- 
 imide C 6 H 4 (CO) 2 NBr occurring as an intermediate product in the latter 
 reaction, and melting at 206 or 207, is also obtained from sodium 
 phthalimide with one molecule bromine in aqueous solution at o ; 
 chloryl-phthalimide C 6 H 4 (CO) 2 NC1, m.p. i83-i85, is obtained by the 
 action of chlorine upon phthalimide shaken up with water (C. 1903, 
 I. 744). With sodium alcoholates these compounds give, in the first 
 instance, carbox-alkyl-anthranilic acid ester (B. 33, 21). 
 
 From phthalic acid and aniline we obtain sym. phthalanile C 6 H 4 (CO) 2 
 
 NC e H 5 , m.p. 208. Unsym. phthalanile C 6 H 4 {^ C H5) )>O, m.p. 116, 
 
 is obtained from phthalanilic acid with acetyl chloride (B. 32, 1991 ; 
 36, 996 ; C. 1903, II. 432). 
 
 Phthalyl-phenyl-hydrazide C 6 H 5 (CO) 2 (NHNHC 6 H 5 ) 2 melts at 161. 
 Phthalyl-hydrazin C 6 H 4 (CO) 2 (NH) 2 , from phthalic anhydride and 
 hydrazin hydrate, sublimes at 200. Phthalimide and hydrazin yield 
 an isomeric phthal-hydrazin (B. 28, R. 429 ; 29, R. 987). 
 
 a-Phthalyl-phenyl-hydrazin C 6 H 4 (CO) 2 N.NHC 6 H 5 melts at 178. 
 
 jS-Phthalyl-phenyl-hydrazin C 6 H 4 {^ *? melts at 210 (B. 19, 
 
 L CxOpJC/gHg 
 
 R. 303 ; 20, R. 255). 
 
 Phthalyl-hydroxylaminie acid C 6 H 4 (COOH)C(OH)NHOH, m.p. 220 
 with decomposition, from cold phthalic anhydride and hydroxylamine. 
 On heating the solution it becomes phthalyl-hydroxylamine C 6 H 4 (CO 2 ) 
 NOH, m.p. 230 ; both bodies are transformed into anthranilic acid 
 by treatment with alkali (C. 1902, I. 1083 ; II. 1286, 1439). 
 
 Phthalyl-glycocoll C 6 H 4 (CO) 2 NCH 2 COOH, m.p. 192, formed by 
 introducing glycocoll into molten phthalic anhydride ; sodium ethylate 
 transposes the ester into the iosmeric oxy-iso-carbo-styrile-carboxylic 
 
358 ORGANIC CHEMISTRY 
 
 ester (q.v.) (B. 33, 981 ; 40, 4409) ; the chloride, m.p. 85, decomposes 
 on distillation, at ordinaty pressure, into CO and chloro-methyl-phthal- 
 imide C 6 H 4 (CO) 2 N.CH 2 C1. Phthalyl-alanin C 6 H 4 (CO) 2 N.CH (CH 3 )CO 2 H, 
 m.p. 162 ; chloride, m.p. 73. j3-Phthalimido-propionie acid C 6 H 4 
 (CO) 2 N.CH 2 .CH 2 CO 2 H, m.p. 151; chloride, m.p. 108 (B. 38, 633; 
 41, 242). 
 
 Nitrites of Phthalic Acid. o-Cyano-benzoic acid is produced when 
 anthranilic acid is treated with nitrous acid and cuprous cyanide. It 
 rearranges itself, upon the application of heat, into phthalimide (B. 18, 
 1496; 19, 2283; 25, R. 910). o-Cyano-benzoic acid ester melts 
 at 70 (B. 19, 1491). o-Cyano-benzo-triehloride CN[2]C 6 H 4 CC1 3 , 
 m.p. 94 and b.p. 280, is obtained from o-tolu-nitrile (B. 20, 3199). 
 o-Cyano-benzamide, o-phthalo-nitrilamide, is formed, besides other pro- 
 ducts, on brief heating of phthalimide with acetic anhydride, and in 
 the transformation of o-cyano-benzol chloride with hydroxylamine. 
 On heating above the m.p. (173), it passes into the isomeric imido- 
 phthalimide ; and, on boiling with excess of acetic anhydride, into 
 o-phthalo-nitrile (B. 40, 2709). 
 
 o-Phthalo-nitrile C 6 H 4 [i, 2](CN) 2 , m.p. 141, is also obtained from 
 o-amido-benzo-nitrile through the diazo-compound (B. 29, 630). 
 
 Substituted o- Phthalic Acids are obtained, partly by direct substitu- 
 tion of the phthalic acid, and partly by the oxidation of substituted 
 naphthalins and toluic acids. 
 
 All the mono- and dichloro-phthalic acids are known : 
 
 4-Chloro-phthalic anhydride . m.p. 98 b.p. 297 
 
 3-Chloro-phthalic anhydride . 122 313 
 
 4, 5-Dichloro-phthalic anhydride . 186 313^ 
 
 3, 4-Dichloro-phthalic anhydride . 121 329 I (B. 42, 3532) 
 
 3, 6-Dichloro-phthalic anhydride . 191 339 ) 
 3, 5-Dichloro-phthalic anhydride 89 . . . (C. 1903, I. 140) 
 
 3, 4, 6-Trichloro-phthalic anhydride . 148 . . . (B. 34, 2107) 
 
 Tetrachloro-phthalic anhydride ,, 250. . . (A. 149, 18). 
 
 The mono-, tri-, and tetrachloro-phthalic acids have been obtained 
 by oxidation of the corresponding chlorinated o-toluic acids or naph- 
 thalins. 4, 5-, 3, 4-, and 3, 6-dichloro-phthalic acids are formed to- 
 gether, on conducting chlorine into a solution of phthalic anhydride 
 in fuming sulphuric acid ; and the 3, 5-acid in small quantity by the 
 action of PC1 5 upon dimethyl-dihydro-resorcin (q.v.). 
 
 4, 5-Dibromo-phthalic acid, m.p. 135, and anhydride, m.p. 214, 
 from phthalic anhydride with bromine in concentrated sulphuric acid, 
 or by oxidation of dibromo-naphthalin with nitric acid. On boiling 
 with KHO it gives dioxy-phthalic acid (B. 34, 2741 ; C. 1907, I. 
 1119). 
 
 3- and 4-Iodo-o-phthalic acids melt at 206 and at 182 (B. 29, 1575. 
 R. 792). Tetra-iodo-o-phthalie acid melts at 324-327 (B. 29, 1634), 
 3- and 4-Nitro-o-phthalie acids, melting at 219 and 161 respectively, 
 are formed together on nitrifying phthalic acid ; the anhydrides melt 
 at 164 and 114, the imides at 216 and 202. 3-Nitro-phthalyl 
 chloride, m.p. 77 (B. 34, 3735, 4351 ; C. 1902, II. 359; 1903, II. 430). 
 Concerning the formation of 3-nitro-phthalie ester acids, a-, m.p. 144, 
 and j8-, m.p. 157, and their relation to V, Meyer's esterification .rule, 
 
DICARBOXYLIC ACIDS 359 
 
 see B. 35, 3857. On reduction of nitro-phthalic acids, 3- and 4-amido- 
 phthalic acids are formed (B. 36, 2494). 
 
 Sulpho-o-phthalie acid is obtained by heating naphthols, naphthyl- 
 amines, and naphthalene-sulphonic acids with concentrated sulphonic 
 acid and mercury to 22O-3OO (B. 29, 2806). 
 
 Oxy-o-phthalie acids. They are recognised by the melting-points 
 of their anhydrides, into which they change upon the application of 
 heat. 
 
 3-Oxy-o-phthalic acid anhydride melts at 147 (B. 16, 1965). Di- 
 nitro-3-oxy-o-phthalic acid is juglonic acid, which can also be obtained 
 by the action of nitric acid upon juglone, a naphthalene derivative 
 (B. 19, 168 ; C. 1907, 1. 1120). 4-Oxy-o-phthalie acid anhydride melts at 
 165 (A. 233, 232). p-Dioxy-o-phthalo-nitrile, o-dicyano-hydroquinone 
 (HO) 2 [3, 6]C 6 H 2 [i, 2](CN) 2 +2H 2 O, is formed from quinone with 
 nascent prussic acid ; on heating with concentrated sulpkuric acid it 
 becomes dioxy-phthalimide C 6 H 2 (OH) 2 (CO) 2 NH, which, on boiling with 
 HC1, splits off CO 2 and becomes p-dioxy-benzoic acid (B. 33, 675 ; 
 A. 349, 45). 
 
 Nor-hemi-pinie acid, 3, 4-dioxy-phthalie acid anhydride, melting 
 at 238, is produced when 3, 4-diehloro-methoxy-phthalie acid anhy- 
 dride (C1CH 2 O)/; 6 H 2 (CO) 2 O, m.p. 156 the reaction product of PC1 5 
 and hemi-pinic acid at 180 is digested with water. Hemi-pinic 
 anhydride, 3, 4-dimethoxy-phthalic anhydride, melts at 167. The acid 
 is formed, together with opianic acid and meconin, in the oxidation of 
 narcotin ; also with meconin on fusing opianic acid with caustic 
 potash : 
 
 Hemi-pinic acid Opianic acid Meconin. 
 
 Consult B. 29, R. 96, for the hemi-pinamido-acids, the hemi-pinic 
 esters, and the hemi-pinimides. 
 
 6-Amido-hemi-pinic acid is produced on boiling its anhydride with 
 baryta water. The anhydride is azo-opianic acid or 2, 3-dimethoxy- 
 5, 6-anthranile-carboxylic acid. 
 
 Nor-meta-hemi-pinic anhydride melts at 247. Meta-hemi-pinic 
 anhydride melts at 175. Meta-hemi-pinic acid or 4, 5-dimethoxy-o- 
 phthalic acid was obtained in the decomposition of papaverin (B. 24, 
 R. 902). Methylene-meta-hemi-pinic ether acid (CH 2 O 2 )C 6 H 2 (COOH) 2 
 is hydrastie acid, formed in the oxidation of hydrastinine. The oxida- 
 tion of cotarnine yields cotarnic acid or methylene-methyl ether 3, 4, 5- 
 trio%y-o-phthalic acid (CH 2 O 2 )(CH 3 O)C 6 H(COOH) 2 . 
 
 Iso-phthalie acid, benzene-m-dicarboxylic acid c 6 H 4 
 
 melts above 300 and sublimes. It is formed by oxidising m-xylol and 
 m-toluic acid with a chromic acid mixture or permanganate (B. 36, 
 1798) ; by the further oxidation of m-phthalyl alcohol ethyl ether, ob- 
 tained from m-xylylene bromide and alcoholic potash (B. 21, 47), and 
 from m-dicyano-benzol and m-cyano-benzoic acid. The last two 
 methods permit of nuclear syntheses from the corresponding amido- 
 compounds, m-phenylene-diamine and m-amido-benzoic acid. 
 
 The acid is also formed when potassium m-sulpho-benzoate, 
 
360 ORGANIC CHEMISTRY 
 
 m-bromo-benzoate, and benzoate are fused with potassium formate 
 (terephthalic acid is also formed in the last two cases) ; by the action 
 of the ester of chloro-carbonic acid and sodium amalgam upon 
 m-dibromo- benzene ; also by heating hydro-pyro-mellitic and hydro- 
 prehnitic acids. 
 
 Iso-phthalic acid is soluble in 460 parts boiling and 7800 parts cold 
 water. It does not yield an anhydride. Reduction changes it to 
 tetrahydro-iso-phthalic acid. The barium salt C 6 H 4 (CO 2 ) 2 Ba+6H 2 O 
 (A. 260, 30) is very soluble in water (distinction between phthalic and 
 terephthalic acids). 
 
 The dimethyl ester melts at 64. 
 
 The dichloride melts at 41 and boils at 276. The dihydrazide melts 
 at 220. Nitrous acid converts it into iso-phthalazide C 6 H 4 (CON 3 ) 2 , 
 melting at 56. Boiling alcohol converts it into m-phenylene-urethane 
 C 6 H 4 (NHC0 2 C 2 H 5 ) 2 (B. 29, R. 987). 
 
 m-Cyano-benzoic acid melts at 217 (B. 20, 524). 
 
 m-Dicyano-benzol melts at 158 (B. 17, 1430). 
 
 Substituted Iso-phthalic Acids. The 5-chloro-, 5-iodo-, and 5- 
 amido-phthalic acids can be prepared from 5-nitro-iso-phthalic acid. 
 The nitration and sulphonation of iso-phthalic acid produce 5-nitro-iso- 
 phthalic acid and 5-sulpho-iso-phthalic acid (see Benzoic acid). The 
 4-bromo-, 4-iodo-, 4-amido-, and 4-sulpho-iso-phthalic acids are obtained 
 by the oxidation of the corresponding toluic acids (B. 24, 3778 ; 28, 
 84 ; 25, 2795 ; 14, 2278). 2-Nitro- and 2-amido-iso-phthalic acids are 
 formed from 2-nitro-m-xylol (B. 39, 73). 4-Chloro-iso-phthalic acid, 
 m.p. 294 ; 4-acetamido-iso-phthalic acid, m.p. 289 ; and 4, 6-diamido- 
 iso-phthalic acid are obtained from chloro-, acetamido-, and diacet- 
 amido-m-xylol, by oxidation with permanganates (B. 36, 1799, 1803 ; 
 C. 1909, II. 1234). 
 
 Tetraehloro-, tetrabromo-, and tetraiodo-phthalic acids melt at 181, 
 290, and 310 (B. 29, 1632). Tetra-amido-iso-phthalic acid C 6 (NH 2 ) 4 
 (COOH) 2 has been obtained by way of the iso-purpuric acid, which is 
 probably the dinitrile of a dinitro-hydroxylamino-oxy-iso-phthalic 
 acid. 
 
 Homologous Iso-phthalic Acids. There are four theoretically 
 possible methyl-iso-phthalic acids, of which uvitinic acid may be 
 mentioned. 
 
 Uvitinic acid, mesidic acid, ^-methyl-iso-phthalic acid CH 3 [5]C 6 H 3 
 [i, 3](CO 2 H) 2 , melting at 287, is obtained by oxidising mesitylene 
 with dilute nitric acid. Synthetically, it has been prepared from 
 pyro-racemic acid. In this reaction a condensation product resembling 
 an aldol is first formed from two molecules pyro-racemic acid by boiling 
 with baryta water or, better, with NaHO. This product is para-pyro- 
 racemic acid ; two molecules of this condense, with elimination of 
 oxalic acid and water, to form methyl-dihydro-trimesinic acid, which 
 on prolonged boiling with baryta water, or with concentrated H 2 SO 4 , 
 splits off CO 2 and 2H atoms and passes into uvitinic acid (Latin uva, a 
 grape) (Wolff, 305, 125) : 
 
 CO.CO 2 H 
 CH 3 v OHCH 2 .C(OH)^-CO 2 H CH 3 v /CH=C CO 2 H ,<Z 
 
 \/** i \ /"*TT \^' ^\/~*"LT /~*TT r* / 
 
 VV\. ^^3 ~ / \ // ^-tl 3 v-/v\ 
 
 CO 2 H X CH 2 CO CO 2 H CO 2 H X N CH 2 (%-CO 2 H 
 
DICARBOXYLIC ACIDS 361 
 
 If a mixture of pyro-racemic acid and propyl- or iso-butyl-aldehyde 
 is used, we obtain 5-ethyl and 5-iso-propyl-iso-phthalie acid (Dobner, 
 B. 23, 377 ; 24, 1746). Chromic acid oxidises these to trimesinic acid. 
 
 Distilled with lime, uvitinic acid at first yields meta-toluic acid, 
 then toluol. 
 
 Xylidic acid, ^-methyl-iso-phthalic acid CH 3 [4]C 6 H 3 [i, 3](CO 2 H) 2 , 
 melting at 282, is obtained by oxidising pseudo-cumol, xylic acid, 
 and iso-xylic acid with dilute nitric acid. Potassium permanganate 
 oxidises it to trimellitic acid. 
 
 2-Mesityl-iso-phthalic acid, m.p. 235, results from the reduction 
 of 2, 6-dicarbon-phenyl-glyoxylic acid with phosphorus and HI (B. 29, 
 R. 283). 
 
 Oxy-iso-phthalie acids are obtained by the same methods from oxy- 
 benzoic acids and aldehyde-oxy-benzoic acids as the latter are got from 
 phenols and phenol-aldehydes. Amido- and sulpho-carboxylic acids 
 also serve as foundation material (B. 16, 1966 ; 25, R. 9). 
 
 2-Oxy-, 4-oxy-, and 5-oxy-iso-phthalic acids melt at 243, 305, and 
 288 respectively. The 4-oxy-iso-phthalic ethyl ester, m.p. 57, is 
 formed in small quantity in a peculiar condensation process during the 
 action of sodium etlvylate free from alcohol upon glutaconic acid ester 
 (B. 37, 2117). 
 
 5, 2-Nitro-oxy-iso-phthalie acid, m.p. 214, from nitro-malonic 
 aldehyde and acetone-dicarboxylic acid (C. 1900, II. 561). 
 
 Dioxy-iso-phthalic acid, reso-dicarboxylic acid, m.p. 305, see B. 
 32, 2796. 
 
 Oxy-uvitinic Acids. Mention may be made of 4-oxy-uvitinie acid 
 (CH 3 )[5](HO)[4]C 6 H 2 [i,3](CO 2 H) 2 , produced by the action of chloro- 
 form, chloral, or trichloro-acetic ester upon sodium aceto-acetic ester 
 (A. 222, 249). Methenyl-bis-acetic acid ester (Vol. I.) is an intermediate 
 link (A. 297, n). 
 
 Terephthalic acid, benzol-p-dicarbo xylic acid C 6 H 4 [i, 4](CO 2 H) 2 , 
 sublimes without melting. Iso-phthalic acid was obtained from m- 
 derivatives of benzene ; in a similar manner terephthalic acid is 
 formed from p-di-derivatives : p-xylol, p-toluic acid, p-dicyano-benzol, 
 p-cyano-benzoic acid, p-dibromo-benzol, etc. It is obtained in small 
 quantities by the action of Mg and CO 2 upon p-dibromo-benzol (B. 
 38, 3796). 
 
 The best course to pursue in forming terephthalic acid is to oxidise 
 carraway oil (a mixture of cymol and cuminol) with chromic acid ; or 
 it may be prepared from p-toluidin (B. 22, 2178). 
 
 Terephthalic acid is almost perfectly insoluble in water, alcohol, 
 and ether. When reduced it yields di-, tetra-, and hexahydro-tere- 
 phthalic acids. It forms no anhydride. 
 
 The barium salt C b H 4 O 4 Ba+4H 2 O is very slightly soluble in water. 
 The methyl ester melts at 140. 
 
 The chloride melts at 78 and boils at 259. The amie acid melts 
 at 214. The dihydrazide melts above 300. The diazide C 6 H 4 [i, 4] 
 (CON 3 ) 2 melts at 110 (B. 29, R. 987). 
 
 Terephthalic di-super-aeid (?) C 6 H 4 [i, 4](COOOH) 2 , in rather in- 
 soluble explosive needles, from terephthalyl chloride with alkaline 
 H 2 O 2 , is precipitated by CO 2 from the alkaline solution as a mono- 
 sodium salt; its ethyl ester C 6 H 4 (CO 2 .OC 2 H 6 ) 2 , m.p. 37, from tere- 
 
362 ORGANIC CHEMISTRY 
 
 phthalyl chloride with barium ethyl peroxide Ba(O.OC 2 H 5 ) 2 (B. 34, 
 766). ' 
 
 p-Cyano-benzoie acid CN[4]C 6 H 4 CO 2 H, from p-amido-benzoic acid, 
 melts at 214. 
 
 p-Dieyano-benzol C 6 H 4 [i, 4](CN) 2 melts at 215. 
 
 Mononitro-terephthalic acid melts at 259. 
 
 It, and sulpho-terephthalie acid, are produced in the nitration and 
 sulphonation of terephthalic acid. 2, 3-, 2, 6-, and 2, 5-Dinitro-phthalic 
 acids are also known (B. 28, 81). 2, 5-Diamido-terephthalic acid 
 (NH 2 ) 2 [2, 5]C 6 H 2 [i, 4](COOH) 2 is infusible; its diethyl ester is pro- 
 duced by the oxidation of di-imino-succinyl-succinic ester with 
 bromine. Like anthranilic acid, this acid, which contains the same 
 grouping doubled, is capable of forming numerous o-condensation 
 products (C. 1907, II. 542). Consult B. 29, 1625, 2833, for tetra- 
 chloro-, tetrabromo- and tetraiodo-terephthalic acids. 
 
 Alkyl-terephthalic Acids. The oxidation of pseudo-cumol and 
 durol gives rise to 4-methyl-terephthalie acid, a-xylidic acid, melting at 
 282, and to 2, 5-dimethyl-terephthalie acid, j8-eumidic acid (B. 19, 2510). 
 
 Oxy-terephthalie Acids. Oxy-terephthalie acid has been obtained 
 from nitro-terephthalic acid. It sublimes without melting. 3, 5-Di- 
 oxy-terephthalic acid is the most interesting of the three possible dioxy- 
 terephthalic acids. Mention is made of it because of its connection 
 with succinyl-succinic ester. Its diethyl ester may be prepared by 
 withdrawing two hydrogen atoms from succinyl-succinic ester by 
 means of bromine or PC1 5 (B. 22, 2107), or by the action of sodium 
 ethylate upon dibromo-aceto-acetic ester (A. 219, 78). 
 
 2, 5-Dioxy-terephthalie acid (HO) 2 C 6 H 2 (CO 2 H) 2 +2H 2 O crystallises 
 from alcohol in yellow flakes. Ferric chloride imparts a deep-blue 
 coloration to its solution. When rapidly distilled it decomposes into 
 two molecules of carbon dioxide and hydroquinone. 
 
 2, 5-Dioxy-terephthalic ethyl ester crystallises in two distinct forms 
 at the ordinary temperature in yellowish-green prisms or plates ; at 
 higher temperatures in colourless flakes. It also sublimes in the latter 
 form. It melts at 133. In most of its reactions the ester conducts 
 itself like an hydroxyl derivative. It does not combine with hydroxyl- 
 amine or phenyl-hydrazin, and with sodium and alkyl iodides yields 
 dialkyl ether. It, however, does not react with phenyl cyanate 
 (B. 23, 259), and shows some analogies with succino-succinic ester. 
 Hence, it is considered a quinone- or diketo-derivative : 
 
 C0 2 C 2 H 5 or 
 
 Dioxy-terephthalic ester, by reduction (boiling with zinc and hydro- 
 chloric acid in alcoholic solution), is again changed to succinyl-succinic 
 ester (B. 19, 432 ; 22, 2169). A dihydroxamic acid is formed with 
 hydroxylamine hydrochloride ; tetrahydro-dioxy-terephthalie acid is 
 produced at the same time (B. 22, 1280). The different physical 
 modifications of the ester and analogous compounds, according to 
 Hantzsch, correspond to two desmotropic conditions the coloured 
 variety agreeing with the quinone formula, while the colourless corre- 
 sponds to the hydroxyl formula (B. 22, 1294). However, the colour 
 cannot be regarded as a certain criterion for the distinction of the 
 
DICAIJBOXYLIC ACIDS 363 
 
 ketone from the hydroxyl form. Even chemical reactions do not 
 prove that desmotropic forms can be accepted (Nef, B. 23, R. 585 ; 
 Goldschmidt, B. 23, R. 260). 
 
 Succinyl-succinic acid, whose ester, by the removal of hydrogen, 
 yields 2, 5-dioxy-terephthalic ester, will be discussed in connection 
 with the hydro-aromatic compounds. 
 
 Trioxy-dicarboxylic Acids. Phloro-glucin-dicarboxylie ester, whose 
 formation by the condensation of three molecules sodium-malonic ester 
 was mentioned in the discussion of benzene ring formations, is dealt 
 with as a derivative of triketo-cyclo-hexane among the hydro-aromatic 
 compounds. 
 
 Gallo-earboxylie acid, trioxy-o-phthalic acid (HO) 3 [3, 4, 5]C 6 H 
 (CO 2 H) 2 , melts at 270 with decomposition. It may be prepared from 
 pyrogallol by heating it to 130 with ammonium carbonate. Pyro- 
 gallo-carboxylic acid is formed at the same time (B. 13, 1876). 
 
 (b) Aromatic Dicarboxylic Acids containing iCO 2 H in the nucleus 
 and iCO 2 H in the side chain. The three a-homo-phthalic acids, or 
 phenyl-acetic-carboxylic acids, are known. The o-acid readily forms 
 heterocyclic derivatives. 
 
 Phenyl-aceto-o-carboxylic acid, o-a-homo-phthalic acid CO 2 H[2] 
 C 6 H 4 CH 2 .CO 2 H, melting at 175, with the elimination of water, may 
 be obtained by fusing gamboge with caustic potash (B. 19, 1654) ; by 
 oxidising indene with KMnO 4 (B. 32, 29) ; by reducing phthalonic 
 acid with HI (B. 31, 375) ; and by saponification of its nitriles. Its 
 anhydride melts at 141. On heating, it splits off CO and becomes 
 hydro-diphthal-lactonic acid (B. 31, 376). 
 
 o-Homo-phthalimide, melting at 233, is produced when the 
 ammonium salt is heated, and when acids act upon the dinitrile. In 
 the latter case o-cyano-phenyl-acetic acid, produced at first, rearranges 
 itself into homo-phthalimide, just as o-cyano-benzoic acid yields 
 phthalimide (B. 23, 2478). It is rather remarkable that o-homo- 
 phthalimide, when heated with phosphorus oxy-chloride, yields 
 dichloro-iso-quinolin, which becomes iso-quinolin when further heated 
 with hydriodic acid (B. 27, 2232, 2492) : 
 
 / ( [i]CH 2 CN /CH 2 .CO POCI, /CH : CC1 ,CH : CH 
 
 CeH/J ^C 6 H 4 < | >C fl H 4 <( | *C 6 H 4 < 
 
 x ( [2]CN X CO . NH X CC1 : N X CH : N 
 
 o-Cyano-benzyl Homo-phthali- Dichloro-iso-quino- Iso-quinolin. 
 
 cyanide mide lin 
 
 Homo-phthalimide is directly converted into iso-quinolin when it 
 is heated with zinc dust. 
 
 The hydrogen atoms of the CH 2 groups are replaced by two alkyls 
 when homo-phthalimide is heated with caustic potash and alkyl 
 iodides. Afowo-alkyl-o-benzyl cyanides yield mono-alkyl-homo-phthal- 
 imides, which rearrange themselves in the same manner as homo-phthal- 
 imide into alkyl-iso-quinolins (B. 20, 2499). 
 
 w-Cyan-o-toluic acid CO 2 H[2]C 6 H 4 CH 2 CN melts with decom- 
 position at 116. Its potassium salt is obtained from phthalide and 
 potassium cyanide (A. 233, 102). 
 
 o-Cyano-benzyl cyanide, o-fi-homo-phthalo-nitrile CN[2]C 6 H 4 CH 2 CN, 
 melting at 81, is obtained from o-cyano-benzyl chloride. Caustic potash 
 and alkylogens effect the replacement of an hydrogen atom in the 
 
364 ORGANIC CHEMISTRY 
 
 methylene group by an alcohol radicle (see Homo-phthalimide) . Acetyl 
 chloride converts it into 0-diaeetyl-o-eyano-benzyl cyanide CN.C 6 H 4 C 
 (CN) : C(CH 3 )OCOCH 3 , which may be rearranged into 3-methyl-iso- 
 quinolin (B. 27, 2232). 
 
 Homo-iso-phthalic acid and homo-terephthalie acid melt at 185 
 (B. 36, 3611). Both sublime, m- and p-Cyano-benzyl cyanides melt 
 at 88 and 100 (B. 24, 2416). The dinitrile, and the two nitrite- and 
 amine-acids, the two possible amido-nitriles, and the diamide of homo- 
 terephthalic acid have been prepared (B. 22, 3207 ; 26, R. 89, 602). 
 
 o-Hydro-cinnamic-carboxylic acid CO 2 H[2]C 6 H 4 CH 2 CH 2 CO 2 H melts 
 at 165. It is formed by oxidising tetrahydro-/3-naphthyl-amine with 
 potassium permanganate, and by the reduction of dihydro-iso-cumarin 
 carboxylic acid (B. 26, 1841), as well as from o-carbo-phenyl-glyceric- 
 acid-S-lactone (B. 25, 888). It yields a-hydrindone (B. 26, 708) upon 
 dry distillation. 
 
 o-Cyano-benzyl-acetie ester, eyano-hydro-cinnamic ester CN[2]C 6 H 4 
 [i]CH 2 .CH 2 .CO 2 C 2 H 5 , melting at 98, is produced by the rearrange- 
 ment of the product resulting from the action of aceto-acetic ester, or 
 malonic ester, and sodium ethylate upon cyano-benzyl chloride (B. 22, 
 2017). Concentrated hydrochloric acid converts it into a-hydrindone 
 
 (q.v.) : C 6 H 4 <^>CH 2 . 
 
 Phenyl-butyric-o-carboxylic acid CO 2 H[2]C 6 H 4 CH 2 .CH 2 .CH 2 .CO 2 H 
 melts at 138 (B. 18, 3118). 
 
 (c) Aromatic Diearboxylic Acids, having both carboxyls in different 
 side-groups. 
 
 o-, m-, and p-Phenylene-diaeetie acids C 6 H 4 (CH 2 CO 2 H) 2 , melting at 
 150, 170, and 244, have been obtained from the xylylene cyanides 
 (B. 26, R. 941). o-Phenylene-diacetic acid has also been prepared by 
 oxidising dihydro-naphthalene (q.v.). Its calcium salt yields /3-hydrin- 
 done upon distillation (q.v.) (B. 26, 1833). 
 
 o-Phenylene-aeeto-propionic acid C 6 H 4 (CH 2 .COOH)[2](CH 2 .CH 2 
 COOH), m.p. 139, is obtained from J3-oxy-a-naphthoic acid, by 
 rupture of the ring, effected by sodium and amyl alcohol, just as pimelic 
 acid is formed from salicylic acid. It reverts to j8-keto-tetrahydro- 
 naphthalene when its calcium salt is distilled (B. 28, R. 745). 
 
 o-, m-, and p-Phenylene-dipropionic acids C 6 H 4 (CH 2 .CH 2 .CO 2 H) 2 , 
 m.p. 161, 146, and 223, are formed from xylylene-dimalonic acids 
 (B. 19, 436 ; 21, 37). Also p-phenylene-di-iso-butyric acid C 6 H 4 [CH 2 
 CH(CH 3 )COOH] 2 , m.p. 169, from p-xylylene-dimethyl-malonic acid 
 (B. 34, 2789). 
 
 (9) ALDEHYDO-DICARBOXYLIC ACIDS. 
 
 2-Aldehydo-iso-phthalic acid, m.p. 176, results from heating 
 2, 6-dicarbo-phenyl-glyoxylic acid (B. 26, 1767 ; 30, 695). 
 
 5-Aldehydo-4-oxy- and 5-aldehydo-2-oxy-iso-phthalie acids are 
 formed from the corresponding oxy-iso-phthalic acids by means of 
 chloroform and caustic potash (B. 11, 793). 
 
 (10) TRICARBOXYLIC ACIDS. 
 
 The three isomeric benzene-tricarboxylic acids C 6 H 3 (CO 2 H) 3 are 
 known. Trimesic acid, (1, 3, 5) -benzol- tricarboxylic acid, melts about 
 
TRICARBOXYLIC ACIDS 365 
 
 300, and sublimes near 300. It is formed (i) when mesitylenic and 
 uvitinic acids are oxidised with a chromic acid mixture ; (2) by heating 
 mellitic acid with glycerol, or hydro- and iso-hydro-mellitic acid with 
 sulphuric acid. A synthetic method for its production consists in 
 (3) heating benzol-i, 3, 5-trisulphonic acid with potassium cyanide, and 
 saponifying the resulting tricyano-benzol. By the condensation of 
 certain aliphatic substances the acid and its esters have been obtained 
 (i) by polymerising propiolic acid ; (2) by the production of its mono- 
 methyl ester through the action of caustic potash upon coumalic acid 
 (B. 24, R. 750) ; (3) its triethyl ester from formyl-acetic ester. 
 
 The intermediate formation of the latter may also explain (4) the 
 synthesis of trimesinic acid ester from formic and halogen-acetic esters 
 with zinc (C. 1898, II. 472). 
 
 Its trimethyl ester melts at 143. Its triethyl ester melts at 133. 
 
 Trimellitic acid, (r, 2, 4)-benzol-tricarboxylic acid. This is obtained 
 (together with iso-phthalic acid) by heating hydro-pyro-mellitic acid 
 with sulphuric acid, or upon oxidising xylidic acid with potassium 
 permanganate, also from amido-terephthalic acid (B. 19, 1635). It 
 is prepared most readily (along with iso-phthalic acid) by oxidising 
 colophonium with nitric acid (A. 172, 97). It melts at 216, decompos- 
 ing into water and the anhydride C 6 H 2 (CO 2 H)(CO) 2 O. The latter 
 melts at 158. 
 
 Hemi - mellitic acid, (i, 2, 3)-benzol-tricarboxylic acid. This is 
 formed on heating hydro-mellophanic acid (below) with sulphuric 
 acid, as well as in the oxidation of phenyl-glyoxyl-dicarboxylic acid, 
 formed from naphthalic acid by action of KMnO 4 (B. 29, 283). It 
 melts at 185 and decomposes into phthalic anhydride. Triethyl ester, 
 m.p. 39 (B. 29, R. 283 ; 31, 2084). 
 
 Oxy-tricarboxylic acids have been obtained from the sulpho-tri- 
 carboxylic acids : oxy-trimesie acid (A. 206, 204) ; oxy-trimellitic acid 
 see B. 16, 192. 
 
 The condensation of sodium-acetone-dicarboxylic ester into dioxy- 
 phenyl-aceto-dicarboxylic ester is dealt with in connection with hydro- 
 aromatic compounds. 
 
 (n) AROMATIC TETRACARBOXYLIC ACIDS. 
 
 The three isomerides are known. Reduction converts them into 
 tetrahydro-benzol-tetracarboxylic acids (see these). 
 
 Pyro-mellitic acid, i, 2, 4, $-benzene-tetracarboxylic #aWC 6 H 2 (CO 2 H) 4 
 -f-2H 2 O, melts when anhydrous at 264, and decomposes into water 
 and its anhydride, which is produced when mellitic acid is distilled, 
 or, better, when the sodium salt is subjected to the same treatment 
 with sulphuric acid. The acid is also produced by oxidising durol 
 and durylic acid with potassium permanganate. 
 
 The di-anhydride C 6 H 2 (^o) 2 melts at 286. The ethyl ester 
 
 C 6 H 2 (C0 2 .C 2 H 5 ) 4 melts at 53. 
 
 Dinitro- and diamido-hydro-mellitie tetra-ethyl esters melt at 130 
 and 134. Nitric acid oxidises the diamido-ether to 
 
 Quinone-tetracarboxylic ester C 6 (O 2 )(CO 2 .C 2 H 5 ) 4 , crystallising in 
 quinone-yellow needles, melting at 149. It is odourless, but sublimes 
 quite readily. Zinc reduces it in glacial acetic acid solution to 
 
366 ORGANIC CHEMISTRY 
 
 Hydroquinone-tetracarboxylic ester C 6 (OH) 2 (CO 2 .C 2 H 5 ) 4 , crystallis- 
 ing in bright yellow needles, melting at 127. It may be obtained 
 from sodium-acetone-dicarboxylic ester with iodine (B. 30, 2570). In 
 alcoholic solution it is reduced by zinc dust and hydrochloric acid to 
 p-diketo-hexamethylene-tetracarboxylic ester (A. 237, 25). 
 
 Prehnitic acid, (i, 2, 3, 4)-benzene-tetracarboxylic acid C 6 H 2 (CO 2 H) 4 
 -f2H 2 O melts when anhydrous at 237, with the formation of an an- 
 hydride. It results (together with mellophanic acid and trimesic acid) 
 upon heating hydro- and iso-hydro-mellitic acid with sulphuric acid, 
 also by oxidising prehnitol with potassium permanganate (B. 21, 907). 
 The salts of this acid form crystals resembling the mineral prehnite. 
 
 Mellophanic acid, (i, 2, 3, $)-benzene-tetracarboxylic acid, melts at 
 238, with anhydride formation. It is formed by the oxidation of 
 iso-durol with KMnO 4 ; see Prehnitic acid. 
 
 (12) AROMATIC PENTACARBOXYLIC ACID. 
 
 Benzene-pentacarboxylic acid C 6 H(CO 2 )H 5 +6H 2 O decomposes 
 when it is melted. It is produced by oxidising pentamethyl-benzene 
 with permanganate (B. 17, R. 376). Also from charcoal with concen- 
 trated sulphuric acid (C. 1901, II. 108). 
 
 (13) AROMATIC HEXACARBOXYLIC ACID. 
 
 Mellitic acid C 6 (CO 2 H) 6 . When heated it melts and decomposes 
 into water, carbon dioxide, and pyro-mellitic anhydride. 
 
 Honey-stone, found in some lignite beds, is an aluminium salt of 
 mellitic acid, crystallising in large quadratic pyramids of bright yellow 
 colour (B. 10, 566). 
 
 An interesting formation of mellitic acid is that whereby pure 
 carbon (graphite, charcoal, etc.) is oxidised with an alkaline solution 
 of potassium permanganate. Another is when the carbon is applied 
 as positive electrode in electrolysis (B. 16, 1209), and also the oxida- 
 tion of hexamethyl-benzol with KMnO 4 . 
 
 As hexamethyl-benzol can be synthesised, this latter method of 
 formation would be a synthesis of mellitic acid. 
 
 Mellitic acid crystallises in fine silky needles, readily soluble in 
 water and alcohol. It is very stable, and is not decomposed by acids, 
 by chlorine or by bromine, even upon boiling. It yields benzene when 
 distilled with lime. 
 
 History. Klaproth (1799) discovered mellitic acid by boiling 
 honey-stone for a long period with water, and named it honey-stone 
 acid. In 1870 Baeyer proved that mellitic acid was nothing more than 
 benzol-hexacarboxylic acid, in that, by heating with lime, he obtained 
 benzene, and by reduction found hexahydro-mellitic acid (A. suppl., 7, i). 
 
 Salts and Esters. The barium salt C 12 Ba 3 O 12 +3H 2 O is insoluble 
 in water. The methyl ester melts at 187 ; the ethyl ester melts at 73. 
 
 The chloride C 6 (COC1) 6 melts at 190. 
 
 Mellimide, paramide C 6 (^\Nn) is formed in the dry distilla- 
 
 \C^vJ/ /3> 
 
 tion of the ammonium salt. It is a white, amorphous powder, insoluble 
 in water and alcohol. Heated to 200 with water, it is converted into 
 
PHENYL-GLYCOLS 367 
 
 the tri-ammonium salt of mellitic acid. The alkalies convert paramide 
 into euchroic acid. 
 
 Euchroie acid C 6 [(CO) 2 NH] 2 {'^ crystallises in colourless 
 
 prisms. Heated with water to 200, it yields mellitic acid. Nascent 
 hydrogen changes euchroic acid to euchrone, a dark-blue precipitate, 
 which reverts to colourless euchroic acid upon exposure. Euchrone 
 dissolves with a dark-red colour in alkalies. 
 
 3. Aromatic Polyalcohols, containing more than one Hydroxyl Group 
 in the same Side Chain, and their Oxidation Products. 
 
 Of the aromatic polyalcohols, having the hydroxyl groups attached 
 to different carbon atoms of the same side chain, it is only the glycols, 
 and their oxidation products, which have been studied in any sense 
 completely. A more detailed classification of the polyhydric alcohols 
 and their oxidation products is therefore unnecessary ; the compounds 
 belonging here will, for practical considerations, be included with the 
 glycols and their oxidation products. 
 
 (i) PHENYL-GLYCOLS AND PHENYL-GLYCERIN. 
 
 Phenyl-glycols are produced (i) from the dibromides or bromo- 
 hydrins of the olefin-benzols with potassium carbonate or baryta 
 water ; (2) by gentle oxidation of the olefin-benzols with potassium 
 permanganate ; (3) by nuclear synthesis in the action of alkyl- 
 magnesium haloids upon aromatic oxy-acid esters and oxy-ketones, e.g. 
 C6H 5 CH(OH)C0 2 R .JEM5U C 6 H 5 CH(OH).C(OH)(CH 3 ) 2 . On heating 
 with dilute sulphuric acid the i, 2-phenyl-glycols split off water and 
 form aldehydes and ketones, the primary-secondary and primary- 
 tertiary glycols becoming aldehydes without transposition, and the 
 di-secondary and secondary-tertiary glycols becoming ketones, or alde- 
 hydes, with migration of the phenyl group (Tiffeneau, C. 1907, I. 1577). 
 
 Styrolene alcohol C 6 H 5 .CH(OH).CH 2 .OH, phenyl-glycol, melts at 
 67, boils at 273, and is obtained from styrol dibromide by the action 
 of a potash solution. Dilute nitric acid oxidises it to benzoyl-carbinol 
 and benzoyl-formic acid (A. 216, 293). 
 
 Heated with dilute sulphuric acid, it becomes phenyl-acetaldehyde. 
 By the action of 65 per cent, sulphuric acid two molecules are condensed 
 to j8-phenyl-naphthalin (g.v.). Methylene ether, b.p. 218, from 
 phenyl-glycol and formaldehyde (B. 32, 568). 
 
 Sym. phenyl-methyl-glycol C 6 H 5 CH(OH).CH(OH).CH 3 , a-modifi- 
 cation, m.p. 57, /^-modification, m.p. 93. This glycol occurs, like 
 hydro-benzoin, in two modifications, generated from the corresponding 
 dibromide (from n-propyl-benzol) . Both modifications, on boiling 
 with dilute H 2 SO 4 , yield phenyl-acetone, and, on oxidation with HNO 3 , 
 phenyl-methyl-glyoxal (B. 43, 849). 
 
 Unsym. phenyl-methyl-glycol C 6 H 5 (CH 3 )COH.CH 2 OH, m.p. 41, 
 b.p. 26 161, by methods i and 3; yields on heating with dilute 
 H 2 SO 4 hydratropic aldehyde (C. 1907, I. 1578). 
 
 l-Phenyl-2, 3-propylene-glycol C 6 H 5 CH 2 .CH(OH).CH 2 (OH), b.p. 12 
 i63,andl-phenyl-3,4-butylene-glycolC 6 H 5 CH 2 .CH 2 .CH(OH).CH 2 (OH), 
 
3 68 ORGANIC CHEMISTRY 
 
 b.p-14 I 7S, are formed by the action of phenyl- and benzyl-magnesium 
 bromide respectively, upon glycerin-a-monochloro-hydrin (C. 1905, 
 II. 1752 ; 1907, I. 1033). 
 
 Sym. dimethyl- and diethyl-phenyl-glyeol C ? H 5 CH(OH).C(OH)R 2 , 
 m.p. 63 and 78, by method 3. On heating with dilute H 2 SO 4 they 
 pass into dimethyl- and diethyl-phenyl-acetaldehyde respectively, with 
 " phenyl migration " (C. 1909, I. 1335). 
 
 Phenyl-butylene-glycol C 6 H 5 CH(OH)CH 2 .CH 2 .CH 2 (OH), melting at 
 75, is obtained by reduction from benzoyl-propionic aldehyde and 
 benzovl-propyl alcohol. 
 
 Phenyl-iso-propyl-ethylene-glyeol C 6 H 5 CH(OH)CH(OH)CH(CH 3 ) 2 , 
 melting at 81 and boiling at 286, results from the reduction of benz- 
 aldehyde and iso-butyl-aldehyde. 
 
 Methylene-m, p-dioxy-benzyl-glycol [CH 2 2 ][ ? , 4]C 6 H 3 CH 2 CH(OH) 
 CHo(OH) melting at 82, and methylene-m, p-dioxy-phenyl-ethylene- 
 methyl-glyeol (CH 2 O 2 )[ 3 , 4]C 6 H 3 .CH(OH).CH(OH).CH 3 , melting at 
 101, result from the action of KMnO 4 (B. 24, 3488) upon safrol and 
 iso-safrol. The corresponding glycols, melting at 68 and 88, are 
 obtained from anethol, eugenol, and iso-eugenol. 
 
 Stycerine C 6 H 5 .CH(OH).CH(OH).CH 2 .OH, a rubber-like mass, is 
 obtained from styrone bromide and cinnamic alcohol, C 6 H 5 .CHBr. 
 CHBr.CH 2 .OH, with potassium permanganate (B. 24, 3491). 
 
 Phenyl-alkylene oxides are obtained from the halogen hydrins of 
 the phenyl-glycols by treatment with alkali. On heating by themselves, 
 or by warming with dilute sulphuric acid, they are converted into 
 aldehydes or ketones (C. 1905, II. 1628). _ 
 
 Styrol oxide, phenyl-zthylene oxide C 6 H 5 CH O.CH 2 , b.p. 191, from 
 phenyl-glycol-iodo-hydrin and caustic potash ; gives phenyl-acetalde- 
 hyde and diphenyl-diethylene oxide with dilute acids (C. 1908, 1. 1776). 
 
 Unsym. phenyl-methyl-ethylene oxide C 6 H 6 (CH 3 )C.O.CH 2 , b.p. 17 
 85-88, converted into hydratropic aldehyde with dilute acids or on 
 heating'alone (B. 38, 1969). _ 
 
 Sym. phenyl-methyl-ethylene oxide C 6 H 5 CH.O.CH.CH 3 , b.p. 15 93, 
 y-Phenyl-propylene oxide C 6 H 5 CH 2 CH.O.CH 2 , b.p. 15 94-9 8 ( c - T 95, 
 
 II- 237). 
 
 Haloid Esters of the Phenyl-glycols. (a) Halogen Hydrins. Of 
 
 particular interest is the behaviour of the halogen hydrins of phenyl- 
 glycols in the presence of silver nitrate and mercuric oxide respec- 
 tively. While caustic alkalies transform them, as above mentioned, 
 into the corresponding alkylene oxides with elimination of hydrogen 
 haloids, the action of silver nitrate, or mercuric oxides, with the same 
 elimination, produces aldehydes and ketones respectively, with migra- 
 tion of the phenyl group (Tiffeneau, C. 1907, I. 1577) : 
 
 C.H 6 CH(OH).CHLCH 3 -=^U OCH.CH/ 
 
 ^ 
 
 C H 6\C(OH).CH 2 I -=^-> CH 3 CO.CH 2 .C 6 H 6 . 
 CH/ 
 
 That in these transpositions the splitting off of HI probably takes 
 place at the same carbon atom, is indicated by the fact that the iodo- 
 
PHENYL-GLYCOLS 369 
 
 hydrin ethers, treated with mercuric oxide, also pass into phenyl- 
 vinyl ethers with migration of the phenyl (C. 1908, 1. 828) : 
 
 TTT 
 
 CH 3 OC 6 H 4 CH(OC 2 H 6 ).CHI.CH 3 > C 2 H 5 OCH : 
 
 a-Phenyl-ethylene-j3-iodo-hydrin C 6 H 5 CH(OH).CH 2 I, b.p. 18 148- 
 152, with decomposition into HI and aceto-phenone ; formed from 
 styrol (q.v.) with iodine, and yellow HgO, in aqueous etheric solution. 
 The isomeric a-phenyl-ethylene-a-iodo-hydrin C 6 H 5 CHI.CH 2 (OH), 
 m.p. 79, is obtained by the attachment of HI to styrol oxide (C. 1908, 
 I. 42, 1777). 
 
 j3-Phenyl-propylene-glyeol-a-ehloro-hydrm C 6 H 5 (CH 3 )C(OH) .CH 2 C1, 
 b.p. 17 124, is formed by the action of C 6 H 5 MgBr upon chloro-acetone 
 and of CH 3 MgI upon co-chloro-aceto-phenone, or by the attachment 
 of hypo-chlorous acid to iso-propenyl-benzol. 
 
 Bromo-hydrin, b.p. 19 141. lodo-hydrin, b.p. 12 145 (C. 1907, I. 
 1200). 
 
 Benzyl-glycol-chloro-hydrin C 6 H 5 CH 2 CH(OH).CH 2 C1, b.p. 27 153, 
 by the action of C 6 H 5 MgBr upon epi-chloro-hydrih (C. 1908, I. 830). 
 
 (b) Dihaloids. These are formed by the attachment of halogens 
 to olenn-benzols. In the dibromides of the olenn-phenols, and their 
 ethers, as in the oxy-phenyl (or pseudo-phenol) haloids, the bromine 
 atom occupying the a-position towards the phenyl group is very mobile, 
 and by treatment with aqueous acetone, sodium alcoholate, potassium 
 acetate, aniline, etc., it can be easily replaced by the groups OH, OC 2 H 5 , 
 OCOCH 3 , or NHC 6 H 5 . The action of concentrated nitric acid upon 
 these dibromides is peculiar, the a-bromine atom migrating to the 
 nucleus, and a-ketones being formed. Thus anethol dibromide yields 
 (CH 3 O)BrC 6 H 3 CO.CHBr.CH 3 (B. 38, 3458). 
 
 Styrol dichloride, a, p-dichloro-ethyl-benzol C 6 H 5 CHC1CH 2 C1, liquid. 
 Styrol dibromide, m.p. 60. Anethol dibromide CH 3 OC 6 H 4 CHBr. 
 CHBrCH 3 ,m.p. 65. Iso-safrol dibromide CH 2 (O) 2 C 6 H 3 CHBr.CHBrCH 3 , 
 liquid (B. 28, 2719). 
 
 Phenyl-oxalkyl-amines. These compounds have attained great 
 importance since it has been found that adrenalin, a body of great 
 physiological significance, belongs to this class of compounds. These 
 substances are obtained (i) from phenyl-glycol halogen hydrins by 
 transformation with amines ; (2) by reduction of the aromatic amido- 
 ketones ; and (3) of the oxy-acid nitriles. 
 
 Phenyl-oxethyl-amine C 6 H 5 CH(OH).CH 2 NH 2 . The chlorohydrate 
 melts at 177, the picrate at 154. By reduction of mandelic acid 
 nitrile with sodium amalgam (C. 1908, I. 430). 
 
 l-Methyl-amido-2-phenyl-2-propanol C 6 H 5 (CH 3 )C(OH) .CH 2 NHCH 3 , 
 b -P-33 I 37 J an d l-methyl-amido-3-phenyl-2-propanol C 6 H 5 CH 2 .CH 
 (OH).CH V NHCH 3 , b.p. 20 148, by method i (C. 1905, I. 232). 
 
 Ephedrin C 6 H 5 CH (OH) .CH (NHCH 8 ) .CH 3 (?) ,m.p. 39; chlorohydrate, 
 m.p. 210, has been isolated from Ephedra vulgaris besides the stereo- 
 isomeric (?) pseudo-ephedrin (B. 22, 1823). By heating with HC1, or 
 acetic anhydride, they can be converted into each other (C. 1910, II. 
 1480) . Both chlorohydrates decompose in dry heat into methyl-amine 
 chloride and propio-phenone (C. 1909, I. 1705). 
 
 3, 4-Dioxy-phenyl-oxethyl-amine (OH) a [s, 4]C 6 H 3 [i]CH(OH).CH 2 
 
 VOL. II. 2 B 
 
370 ORGANIC CHEMISTRY 
 
 NH 2 , white crystalline meal, melting at 191 with decomposition, is 
 formed by the reduction of amido-aceto-pyro-catechin or of proto- 
 catechin - aldehyde - cyano - Irydrin with sodium amalgam (C. 1908, 
 I. 430). 
 
 Adrenalin, suprarenin (HO) 2 [3, 4]C 6 H 3 [i]CH(OH).CH 2 NHCH 3 , 
 m.p. about 216 with decomposition, was isolated in 1901 by J. Taka- 
 mine (C. 1901, II. 1354) from the extract of suprarenal capsules, whence 
 the name (Latin renes, kidneys). It is of great physiological and phar- 
 maceutical importance, since even in very small quantities it produces 
 a great increase of the blood-pressure and a contraction of the peri- 
 pheral blood-vessels. 
 
 Adrenalin is optically active, its specific rotatory power for D being 
 53 '5- It dissolves with difficulty in water and the organic solvents, 
 but easily in acids and alkalies. On heating with NaHO, it decom- 
 poses with elimination of methyl-amine. Methylation, and subsequent 
 oxidation, produce veratric acid. This settles its constitution, which 
 is confirmed by synthesis. The latter starts from chloraceto-pyro- 
 catechin (obtained from pyro-catechin and chloracetyl chloride) , which 
 yields inactive adrenalin by transformation with methyl-amine and 
 reduction with Al amalgam (F. Stolz, B. 37, 4149 ; C. 1905, 1. 315) : 
 
 /MCO.CH.Cl r CO.CH 2 NHCH, ,CH(OH).CH a NHCH, 
 
 C,H { " -> C 6 H 3 { [ 3 ]OH > C,H, { OH > C,H, { OH 
 
 l[ 4 ]OH \OH I OH 
 
 The racemic adrenalin so obtained can be decomposed into its 
 optically active components by means of its tartrates. The laevo- 
 modification agrees in all its properties with the natural product (Z. 
 physiol. Ch. 58, 189). It is remarkable that the physiological effects 
 of lasvo-rotatory adrenalin are about fifteen times as great as those of 
 the dextro-rotatory modification. 
 
 A number of derivatives of adrenalin have been obtained syntheti- 
 cally, and some of them show similar physiological effects. 
 
 Adrenalin-dimethyl ether (CH 3 O) 2 C 6 H 3 CH(OH).CH 2 NHCH 3 , m.p. 
 104, and adrenalin-methylene ether CH 2 (O) 2 C ? H 3 CH(OH).CH 2 NHCH 3 , 
 m.p. 96, are obtained from the bromo-hydrins of the corresponding 
 olefin-phenol ethers, by transformation with methyl-amine (C. 1910, 
 I. 2115). 
 
 (2) PHENYL-ALCOHOL ALDEHYDES. 
 
 Just as two molecules of acetaldehyde condense to aldol, so the 
 nitro-benzaldehydes combine with acetaldehyde, under the influence 
 of very dilute sodium hydroxide (2 per cent.) to the corresponding 
 aldols, the nitro-phenyl-lactic acid aldehydes NO 2 C 6 H 4 CH(OH)CH 2 CHO, 
 which unite with an additional molecule of acetaldehyde. Dehydrating 
 agents, like acetic anhydride, convert them into the corresponding 
 nitro-cinnamic aldehydes (B. 18, 719). 
 
 o-Oxy-mandelie aldehyde, o-oxy-phenyl-glyeol aldehyde HO[2]C 6 H 4 
 CH(OH)CHO, m.p. 64, has been obtained from cumarone dichloride 
 by splitting up with sodium acetate (A. 313, 96). 
 
 Phenyl-glyeerin aldehyde C 6 H 5 CH(OH)CH)OH(CHO ; its dimethyl- 
 acetal, m.p. 80, is formed by oxidation of cinnamic aldehyde-acetal 
 with permanganate ; phenyl-hydrazone, m.p. 170 (B. 31, 1995). 
 
PHENYL KETOLS 371 
 
 Phenyl-tetrose C 6 H 5 .CH(OH)CH.OH.CH(OH).COH is a colourless 
 syrup resulting from the reduction of phenyl-trioxy-butyric acid lactone 
 (q.v.). Its phenyl-hydrazone melts at 154. 
 
 (3) PHENYL KETOLS. 
 
 Aceto-phenone alcohol, benzoyl-carbinol CgHg.CO.CHg.OH, cry- 
 stallises from water and dilute alcohol in large, brilliant flakes, which 
 contain water of crystallisation, and melt at 73. It crystallises from 
 ether in shining anhydrous plates, and melts at 85. It is produced 
 in the oxidation of phenyl-glycol, and from its chloride, o>-chloraceto- 
 phenone, by its conversion into acetate and saponification with potas- 
 sium carbonate (B. 16, 1290 ; 39, 2294). Also from co-diazo-aceto- 
 phenone by means of dilute H 2 SO 4 ; and by the action of benzene and 
 A1C1 3 upon acetyl-gly colic acid chloride (A. 368, 89). 
 
 When distilled it decomposes, with formation of bitter-almond oil. 
 Being a ketone, it forms crystalline compounds with primary alkaline 
 sulphites. With hydroxylamine it forms an oxime, melting at 70; 
 with phenyl-hydrazin, a phenyl-hydrazone, m.p. 112 ; and further, the 
 osazone of phenyl-glyoxal. Like acetyl-carbinol, it reduces a cold 
 ammoniacal silver or copper solution (forming benzaldehyde and ben- 
 zoic acid), and is oxidised to mandelic acid (B. 14, 2100). Nitric 
 acid oxidises it to phenyl-glyoxylic acid. It yields cyano-hydrin 
 with CNH, which then forms a-phenyl-glyceric acid, or atro-glyceric 
 acid (q.v.). 
 
 C 6 H 5 C(O.CH 3 ) O CH 2 
 
 Bis-methyl-benzoyl-earbinol , melt- 
 
 CH 2 - 0-C(OCH 3 )C 6 H 5 (?) 
 
 ing at 192, is formed from benzoyl-carbinol with methyl alcohol and 
 hydrochloric acid (B. 28, 1161). 
 
 Benzoyl-carbinol acetate C 6 H 5 CO.CH 2 .O.COCH 3 melts at 49 and 
 boils at 270. The benzoate melts at 117. The phenyl ether melts 
 at 72. 
 
 co-Chloro-aceto-phenone, phenacyl chloride, benzoyl-carbinol chloride 
 C 6 H 5 COCH 2 C1, melting at 59 and boiling at 245, results from the 
 chlorination of boiling aceto-phenone (B. 10, 1830), as well as from 
 benzene, chloracetyl chloride, and aluminium chloride. 
 
 o)-Bromo-aceto-phenone, phenacyl bromide C 6 H 5 .CO.CH 2 Br, melting 
 at 50, attacks the mucous membrane quite powerfully. It is obtained 
 from aceto-phenone and bromine, also by heating dibromatro-lactinic 
 acid with water (B. 14, 1238). An excess of alcoholic ammonia changes 
 it to iso-indol a hydrazin derivative. With methyl-ethyl sulphide 
 it combines to phenacyl-methyl-ethyl-sulphinium bromide C 6 H 5 COCH 2 S 
 (CH 3 )(C 2 H 5 )Br, which may be split up into optically active components 
 by means of bromo-camphor-sulphonic acid (see unsym. sulphur 
 atom, C. 1900, II. 960). The acid amides and thiamides change the 
 co-haloid aceto-phenones into oxazole and thiazole derivatives (q.v.). 
 With excess of alcoholic ammonia, 'phenacyl bromide passes into 
 diphenyl-dihydro-pyrazin. 
 
 Gallo-chloro-aeeto-phenone C 6 H 2 (OH) 3 COCH 2 C1, and co-bromo- 
 resaeeto-phenone, containing the hydroxyl group in the ortho-position, 
 part with halogen hydrides, and become cumarone derivatives (B. 
 30, 299). 
 
372 ORGANIC CHEMISTRY 
 
 o)-Iodo-aeeto-phenone, phenacyl iodide C 6 H 5 COCH 2 I, m.p. 30, 
 from o>-chloro- or bromo-aceto-phenone with potassium iodide (C. 1899, 
 1.559; B. 32, 532). It forms with Ag nitrite : 
 
 co-Nitro-aeeto-phenone C 6 H 5 COCH 2 .NO 2 , m.p. 108. This is also 
 obtained from its dimethyl-acetal C 6 H 5 C(OCH 3 ) 2 CH 2 .NO 2 , m.p. 56 
 (B. 36, 2558). In potash it dissolves to form the salt C 6 H 5 COCH : 
 NOOK. Stannous chloride reduces it to 
 
 co-Amido-aeeto-phenone C 6 H 5 .CO.CH 2 .NH 2 which is unknown 
 in a free condition. The chlorohydrate C 6 H 5 .CO.CH 2 .NH 2 HC1, 
 melting at 183, is formed when the iso - nitroso - aceto - phenone 
 is reduced with tin and hydrochloric acid (B. 28, 254), or by the 
 breaking up of phthalimino-aceto-phenone C 6 H 4 (CO) 2 NHCH 2 COC 6 H 5 
 with concentrated HC1. The free o> - amido - aceto - phenone is 
 unstable, like the a-amido-ketones of the aliphatic series. Liber- 
 ated from its chlorohydrate with NaHO, or ammonia, it immedi- 
 ately splits off water and passes into diphenyl - dihydro - pyrazin 
 
 C 6 H 6 C^^r^^CC 6 H 5 which is also obtained, with small quantities 
 
 of diphenaeyl-amine (C 6 H 5 COCH 2 ) 2 NH, m.p. 75, by the action of 
 ammonia upon co-bromo-aceto-phenone. Heating with HC1 regenerates 
 the chlorohydrate. With excess of NaHO it loses water, and easily 
 passes into a base isomeric with diphenyl-dehydro-pyrazin, probably 
 3, 5-diphenyl-4-amido-pyrrol NH<(CH==C.NH 2 (R ^ ^ With 
 
 \C(C 6 rl 5 ) : U.L/ 6 H 5 
 
 sodium nitrite the w-amido-aceto-phenone chloride yields o>-diazo- 
 aeeto-phenone, benzoyl-diazo-methane c 6 H 6 COCH<^v, m.p. 50, which 
 
 also results from benzoyl-acetone-diazo-anhydride by splitting up 
 with ammonia. Diazo-aceto-phenone, on boiling with dilute H 2 SO 4 , 
 is decomposed into N 2 and benzoyl-carbinol. With iodine it yields 
 a>-di-iodo-aceto-phenone C 6 H 5 COCHI 2 ; with KCN it forms a potas- 
 sium salt of phenacyl-azo-eyanide C 6 H 6 COCH 2 N : NCN, colourless 
 crystals, m.p. 72 with decomposition, which, with H 2 SO 4 , yields 
 phenaeyl-azo-earbonamide C 6 H 5 .COCH 2 N : NCONH 2 , m.p. 217 with 
 decomposition (A. 325, 141). 
 
 co-Methyl-amido-, dimethyl-amido-aceto-phenone, and co-trimethyl- 
 amido-aceto-phenone bromide C 6 H 5 COCH 2 N(CH 3 )Br are generated 
 from phenacyl bromide with mono-, di-, and trimethyl-amine (C. 1899, 
 I. 1284). 
 
 co-Aceto-phenone-anilide, phenacyl-anilide C 6 H 5 .CO.CH 2 NHC 6 H 5 , 
 m.p. 93, from eo-bromo-aceto-phenone and aniline (B. 15, 2467), may 
 be condensed to a-phenyl-indol (B. 21, 1071, 2196, 2595). 
 
 p-Amido-benzoyl-carbinol NH 2 [4]C 6 H 4 COCH 2 OH, m.p. 165, is 
 obtained by transforming a body obtained synthetically from acet- 
 anilide and chloracetyl chloride by means of A1C1 3 , viz. p-acetamido- 
 phenacyl chloride CH 3 CONHC 6 H 4 COCH 2 C1, m.p. 212 (B. 33, 2644). 
 
 a-Amido-propio-phenone C 6 H 5 .CO.CH(NH 2 )CH 3 , chlorohydrate, 
 m.p. 183, by reduction of iso-nitroso-propio-phenone, or from phthalyl- 
 alanyl chloride, benzol, and A1C1 3 . Like co-amido-aceto-phenone, the 
 free base liberates water and passes spontaneously into 2, $-dimethyl- 
 
 3, 6-diphenyl-dihydro-pyrazin C 6 H 6 C<^~ ( ^^)cc 6 H 6 , from which 
 HC1 generates, besides some of the original amido-ketone, the isomeric 
 
PHENYL KETOLS 373 
 
 a-amido-a-phenyl-acetone C 6 H 5 CH(NH 2 )COCH 3 , which may be ob- 
 tained by reduction of the iso-nitroso-phenyl-acetone (B. 41, 1146). 
 
 Phenyl-aeetyl-carbinol C 6 H 5 CH(OH)COCH 3 , b.p. tt 135, from a- 
 bromo-benzyl-methyl-ketone C 6 H 5 CHBrCOCH 3 by way of the acetate 
 (C. 1904, I. 24). 
 
 a-Benzyl-amido-acetone C 6 H 5 CH 2 CH(NH 2 )COCH 3 whose chloro- 
 hydrate melts at 127, is formed by reduction of iso-nitroso-benzyl- 
 acetone (B. 40, 4666). 
 
 Corresponding to the nitro-phenyl-lactic aldehydes we have o- and 
 p-nitro-phenyl-laetie ketones, m.p. 69 and 58, the condensation pro- 
 ducts of o- and p-nitro-benzaldehyde and acetone, in the presence of 
 very dilute NaHO. By boiling with water or by excess of NaHO the 
 o-nitro-ketone is converted into indigo (q.v.) with rejection of acetic 
 acid and water (B. 16, 1968). See also Nitro-benzylidene-acetones. 
 
 a>-Chloraceto-pyro-cateehin (OH) 2 [3, 4]C 6 H 3 COCH 2 C1, m.p. 173, 
 from pyro-catechin and chloracetyl chloride, yields with methyl-amine 
 co-methyl-amido-aceto-pyro-catechin (OH) 2 C 6 H 3 COCH 2 NHCH 3 , chloro- 
 hydrate, m.p. 240 (B. 37, 4152). 
 
 BenzoyMwtyl-carbinol C 6 H 5 .CO.[CH 2 ] 3 .CH 2 OH, m.p. 40 (B. 23, 
 R. 500). 
 
 j3-Amido-propio-phenone C 6 H 5 COCH 2 .CH 2 NH 2 , chlorohydrate, m.p. 
 128, is formed from a-phthalyl-anyl chloride, benzene, and A1C1 3 . 
 NaHO liberates the free base as an oil (B. 41, 244). 
 
 y-Amido-butyro-phenone C 6 H 5 CO.CH 2 .CH 2 .CH 2 NH 2 is unstable ; 
 
 it passes spontaneously into 2-phenyl-pyrrolin c e H 5 C ^^~ ^ a (B. 
 
 41, 513) with liberation of water. A similar dehydration occurs in 
 S-amido-valero-phenone C 6 H 5 COCH 2 .CH 2 .CH 2 .CH 2 NH 2 , from phthal- 
 imido-valerianic acid, which is easily reduced to 2-phenyl-tetra-hydro- 
 pyridin. On the other hand, -amido-capro-phenone C 6 H 5 CO[CH 2 ] 4 
 CH 2 NH 2 , whose chlorohydrate melts at 154, shows no tendency to 
 split off water. The free base is an oil volatile in steam, and has a 
 peculiar odour (B. 41, 2014). 
 
 Triphenyl-acyl-methyl-amine [C 6 H 5 COCH 2 CH 2 ] 3 N, chlorohydrate, 
 m.p. 201, is formed on heating aceto-phenone, AmCl, and formaldehyde 
 solution ; on distilling with steam, it decomposes, forming phenyl- 
 vinyl-ketone (B. 39, 2181). 
 
 (4) PHENYL-ALDEHYDE KETONES. 
 
 a-Ketone-aldehydes. Phenyl-glyoxal, benzoyl-formaldehyde C 6 H 5 - 
 CO.CH(OH) 2 , melts at 73. The anhydrous aldehyde boils at 142 
 (125 mm.). It has a penetrating odour. It is obtained from its 
 aldoxime, iso-nitroso-aceto-phenone, upon boiling the sodium sulphite 
 derivative with dilute sulphuric acid (B. 22, 2557). Alkalies convert 
 it into almond acid ; potassium cyanide condenses it to benzoyl- 
 formoin, just as it changes benzaldehyde to benzoin. It yields quin- 
 oxalins with o-diamines. 
 
 w-Diehloro-aceto-phenone C 6 H 5 .CO.CHC1 2 boils at 253 (B. 10, 
 531). a;-Dibromo-aeeto-phenone C 6 H 5 .CO.CHBr 2 ., m.p. 36 (B. 10, 
 2010 ; A. 195, 161). co-Dibromo-p-iodo-aceto-phenone (B. 24, 997). 
 co-Dichloro-o-nitro-aceto-phenone melts at 73 (A. 221, 328). o>-Di- 
 
374 ORGANIC CHEMISTRY 
 
 bromo-o-, m-, and p-nitro-aceto-phenone melt at 85, 59, and 98 
 (B. 20, 2203 ; 18, 2240 ; 22, 204). 
 
 Iso-nitroso-aceto-phenone, benzoyl-formoxime C 6 H 5 CO.CH(N.OH), 
 m.p. 127, is obtained from aceto-phenone (B. 24, 1382 ; 25, 3459 ; 
 
 A. 358, 56). It forms diphenyl-pyrazin (q.v.) by reduction. Phenyl- 
 glyoxime C 6 H 5 C(NOH).CH(NOH) is known in two modifications 
 (compare benzile dioximes) : 
 
 C 6 H 5 .C C.H ? C 6 H 5 .C C.H . ? . 
 
 N.OHN.OH M HO.N N.OH U 
 
 Phenyl-amphi-glyoxime, m.p. 168 Phenyl-anti-glyoxime, m.p. 180. 
 
 Phenyl-amphi-gryoxime is produced when hydroxylamine acts 
 upon oj-dibromo-aceto-phenone and iso-nitroso-aceto-phenone. When 
 treated in absolute ether with hydrochloric acid gas, it changes to the 
 anti-modification, which reverts to the amphi-modification by recrystal- 
 lisation from indifferent solvents (B. 24, 3497). See also Phenyl- 
 furoxane. 
 
 a-Phenyl-glyoxal-phenyl-hydrazone C 6 H 5 C(NNHC 6 H 5 )CHO (?),m.p. 
 142, from phenyl-glyoxal with phenyl-hydrazin, and the /Miydrazone 
 C 6 H 5 COCH : NNHC 6 H 5 , two modifications easily converted into each 
 other, m.p. 138 and 114, from benzoyl-acetic acid with diazo-benzol 
 (B. 22, 2557 ; 34, 2001). 
 
 Phenyl - glyoxal - phenyl - osazone C 6 H 5 . C : (N . NH . C 6 H 5 ) . CH : 
 (N.NHC 6 H 5 ) melts at 152. (See Benzoyl-carbinol-phenyl-hydrazone, 
 
 B. 22, 2258). Phenyl-glyoxal-methyl-phenyl-osazone melts at 152 
 (B. 21, 2597). 
 
 p-Toluic formaldehyde CH 3 C 6 H 4 CO.CH(OH) 2 melts at 101 (B. 
 22, 2560). 
 
 ( [i]C CHO 
 
 Anthroxan-aldehyde C 6 Hj | \ o , melting at 72, is formed 
 
 I [2] 
 
 from o-nitro-phenyl-glycidic acid (B. 16, 2222) (compare anthranile). 
 
 jS-Ketone-aldehydes. Formyl-aceto-phenone, or benzoyl-acetaldehyde, 
 was formerly regarded as j8-ket one-aldehyde, in which, as in formyl- 
 acetone, an unsaturated ketol, oxy-methylene-aceto-phenone, is present. 
 This will, therefore, be discussed later in connection with the com- 
 pounds containing an unsaturated side chain. The sodium salt of 
 oxy-methylene-aceto-phenone and hydroxylamine hydrochloride yield 
 benzoyl-aeetaldoxime C 6 H 5 .CO.CH 2 .CH : N.OH, melting at 86, which 
 acetic anhydride converts into cyanaceto-phenone and acetyl chloride 
 into the isomeric phenyl-isoxazole. 
 
 y-Ketone-aldehydes. Benzoyl-propio-aldehyde C 6 H 5 CO.CH 2 .CH 2 . 
 CHO boils at 245. 
 
 (5) PHENYL-PARAFFIN DIKETONES. 
 
 a-Diketones, or ortho-diketones, are produced from their monoximes, 
 the phenyl-iso-nitroso-ketones (compare phenyl-glyoxal) by distillation 
 with dilute acids, or by digesting with amyl nitrite (B. 21, 2177). 
 Benzoyl-acetyl C 6 H 5 .CO.CO.CH 3 , boiling at 214, is a yellow oil with a 
 peculiar odour (B. 21, 2119, 2176). It is formed by the oxidation of 
 the two stereo-isomeric phenyl-methyl-glycols with NO 3 H (B. 43, 855). 
 Acetyl-benzoyl-aeeto-hydrazone CH 3 CO.C(NNHCOCH 3 )C 6 H 5 , m.p. 154, 
 is dissolved in NaHO to the sodium salt of a pseudo-form (B. 36, 3187). 
 
PHENYL-PARAFFIN DIKETONES 375 
 
 a-Oximido-propio-phenone C 6 H 5 .CO.C : (NOH).CH 3 , melting at 113, 
 results from the action of nitrous acid upon methyl-benzoyl-acetic ester, 
 or by the action of diazo-benzol chloride upon an alkaline solution of 
 iso-nitroso-acetone, probably with intermediate formation of a phenyl- 
 azo-aldoxime (B. 40, 737) : 
 
 CH 3 COCH : NOH > [CH 3 COC( : NOH).N : NC 6 H 5 ] > CH 3 COC( : NOH)C 6 H 5 . 
 
 jS-Oximido-propio-phenone, iso-nitroso-phenyl-acetone C 6 H 5 C : (NOH) 
 COCH 3 , from phenyl-acetone, with amyl nitrite and sodium alcoholate. 
 
 Phenyl-methyl-glyoxime C 6 H 5 C : (NOH)C : (NOH)CH 3 , m.p. 118 
 (A. 291, 280). p-Methoxy-phenyl-methyl-glyoxime CH 3 O[4]C 6 H 4 C 
 (NOH).C(NOH)CH 3 , m.p. 206 with decomposition, is formed, beside 
 the corresponding peroxide, m.p. 97, from anethol with nitrous acid 
 (A. 329, 262). 
 
 The p- or meta-diketones result, together with aceto-phenone, (i) 
 from the decomposition of the benzoyl-aceto-acetic esters (B. 16, 2239) ; 
 further, by (2) a remarkable condensation induced by sodium alcoholate 
 (Claisen, B. 20, 2178). 
 
 The jS-diketones behave like the j3-diketones of the fatty series. 
 They dissolve in alkalies. This distinguishes them from the other 
 diketones. They are coloured an intense red by ferric chloride. They 
 condense to isoxazols with hydroxylamine (B. 21, 1150). They form 
 pyrazol compounds with phenyl-hydrazin, just like the oxy-methylene- 
 j8-ketones. 
 
 Benzoyl-acetone, acetyl-aceto-phenone C 6 H 5 .CO.CH 2 .CO.CH 3 , melts 
 at 6i-6o, boils at 26o-262, and readily volatilises with steam. It 
 is formed from benzoyl-aceto-acetic ester, from ethyl benzoate and 
 acetone, or ethyl acetate and aceto-phenone with sodium ethylate, free 
 from alcohol. See B. 27, 1571, for the addition of CNH to benzoyl- 
 acetone. See /. pr. Ch. 2, 48, 489, for the action of urea and guanidin. 
 
 The Cu-compound of benzoyl-acetone gives, with SC1 2 : thio- 
 benzoyl-acetoneS[CH(COCH 3 )COC 6 H 5 ] 2 ,m.p. 95; with S 2 C1 2 : dithio- 
 benzoyl acetone S 2 [CH(COCH 3 )COC 6 H 5 ] 2 , m.p. 118 (C. 1903, II. 243). 
 o-Nitro-benzoyl-aeetone, m.p. 55 (A. 221, 332). Benzoyl-nitro-acetone, 
 in the form of its oxime C 6 H 5 C(NOH).CH(NO 2 )COCH 3 , results from 
 benzylidene-acetone when treated with N 2 O 3 (B. 36, 3021). 
 
 Propionyl-, butyryl-, iso-butyryl-, and valeryl-aeeto-phenones boil at 
 172 (30 mm.), 174 (24 mm.), 170 (26 mm.), and 183 (30 mm.) 
 (B. 20, 2181). 
 
 Phenyl-acetyl-acetone CnHj2O2-C6H5.CH2.CO.CH2.CO.CH3, boiling 
 at 266, results from the decomposition of phenyl-acetyl-aceto-acetic 
 ester (B. 18, 2137). 
 
 The following is a y-diketone : 
 
 Aceto - phenone - acetone, phenacyl-acetone C 6 H 5 .CO.CH 2 .CH 2 .CO. 
 CH 3 , is obtained from aceto-phenone-aceto-acetic ester. It is a 
 yellow oil, boiling with decomposition (B. 17, 2756). 
 
 Being a y-diketone, it can split off water and yield phenyl-methyl- 
 furfurane, phenyl-methyl-thio-phene, and phenyl-methyl-pyrrol. 
 
 Triketones. Phenyl-methyl-triketone, phenyl-triketo-butane, b.p. 24 
 138, is a reddish-yellow oil, combining easily with water to a colourless 
 hydrate melting at 54-58. With acetyl-acetone and similar bodies 
 it forms addition products. It reduces copper salts. Phenyl-triketo- 
 
376 ORGANIC CHEMISTRY 
 
 butane was obtained by the disintegration of its dimethyl-amido-anile 
 C 6 H 5 COC[NC 6 H-N(CH 3 ) 2 ]COCH 3 , m.p. 99, formed from benzoyl- 
 acetone with nitroso-dimethyl-aniline. With diazo-benzol, benzoyl- 
 acetone forms phenyl-azo-benzoyl-aeetone C 6 H 5 COC(HN 2 C 6 H 5 )COCH 3 , 
 m.p. 99. With HNO 2 it gives iso-nitroso-benzoyl-acetone C^COC 
 (NOH)COCH 3 , m.p. 125. This gives, by reduction with zinc and 
 sulphuric acid, benzoyl-amido-acetone, and this again, treated with 
 
 HNO 2 , gives benzoyl-aeetone-diazo-anhydride N ^N CCQC H ' m>p ' 66 ' 
 'This diazo-anhydride is split up by ammonia into acetic acid and 
 diaceto-phenone, and by boiling with water and transposition into 
 nitrogen, CO 2 and benzyl-methyl-ketone C 6 H 5 CH 2 COCH 3 ; for further 
 transformations, see Heterocyclic compounds : furo-[a b]-diazols (A. 
 325, 136). 
 
 Phenacyl-diacetyl-methane C 6 H 5 COCH 2 CH(COCH 3 ) 2 , m.p. 58, from 
 phenacyl bromide and sodium-acetyl-acetone, is both a i, 3- and a i, 4- 
 diketone, and therefore yields both isoxazols and pyrazols, as well as 
 furfuranes and pyrrols (C. 1902, I. 1164). 
 
 Tetraketones. Benzal-bis-aeetyl-acetone C 6 H 5 CH[CH(COCH 3 ) 2 ] 2 
 results from the condensation of benzaldehyde with acetyl-acetone in 
 the presence of piperidin, and has been obtained in the six possible 
 allotropic modifications of the keto- and enol forms with the corre- 
 sponding as- and trans-iorms (C. 1900, I. 1099). 
 
 (6) PHENYL-PARAFFIN ALCOHOL ACIDS. 
 
 A. Monoxy-alcohol Acids. Phenyl-alcohol-carboxylic acids, like 
 the aliphatic-alcohol acids, are produced (i) by the reduction of the 
 corresponding ketonic acids ; (2) from aldehydes and ketones (B. 12, 
 815) by the addition of hydrocyanic acid and the saponification of the 
 a-oxy-acid nitrile ; (3) from the corresponding monohalogen acids ; 
 (4) from unsaturated monocarboxylic acids, etc. 
 
 a- and j3-0xy-acids. Almond acid, phenyl-glyeollie acid C 6 H 5 . 
 *CHOH.CO 2 H, is isomeric with the cresotinic acids, and the oxy-methyl- 
 benzoic acids, or carbinol-benzoic acids. It contains an asymmetric 
 carbon atom, and therefore, like the lactic acid of fermentation, 
 appears in one inactive, decomposable, and two optically active 
 modifications. 
 
 Para-mandelic acid, inactive mandelic acid, melting at 118, is formed 
 (i) from benzaldehyde, prussic acid, and hydrochloric acid (B. 14, 239, 
 1965) ; (2) from benzoyl-formic acid, by reduction with sodium 
 amalgam ; and (3) from phenyl-chloracetic acid by boiling it with 
 alkalies (B. 14, 239), (4) as well as from w-dibromo-aceto-phenone or 
 phenyl-glyoxal by the action of alkalies : 
 
 C 6 H 5 .CO.CHO > C 6 H 5 .CHOH.C0 2 H. 
 
 The production of alcohol and carboxylic acid, which completes 
 itself extra-molecularly in the action of caustic alkali upon benzaldehyde, 
 in the case of the conversion of phenyl-glyoxal into mandelic acid 
 proceeds intra-molecularly. See below for the formation of para- 
 mandelic acid from laevo- and dextro-mandelic acids. 
 
 One hundred parts water at 20 dissolve 15-9 parts of para-mandelic 
 
PHENYL-PARAFFIN ALCOHOL ACIDS 377 
 
 acid. Dilute nitric acid converts it, first, into benzoyl-formic acid, 
 then into benzoic acid. When heated with hydriodic acid it forms 
 phenyl-acetic acid ; with hydrobromic and hydrochloric acids chloro- 
 phenyl or bromo-phenyl-acetic acids are formed. On the decomposi- 
 tion of mandelic acid by sulphuric acid, see C. 1903, II. 284. 
 
 L<zvo- and dextro-mandelic acids melt at 133. They have equal, 
 but opposite, molecular rotatory power. Towards reagents they behave 
 like para-mandelic acid. Laevo-mandelic acid, natural mandelic acid, 
 results upon digesting amygdalin (q.v.) with fuming hydrochloric acid 
 (1848 : Wohler, A. 66, 240). Fermentation of ammonium-para-mande- 
 late with Penicillium glaucum destroys the laevo-acid, and there remains 
 the dextro-acid. Schizomyceten first destroys the dextro-mandelic acid 
 in para-mandelic acid ; the laevo-acid remains (Lewkowitsch, B. 17, 
 2723). The direct splitting up of para-mandelic acid into the dextro- 
 and laevo-acids can be brought about by the crystallisation of the 
 cinchonine salt. The mixing together of the dextro- and laevo-acids 
 (molecular quantities) results in the formation of inactive para-mandelic 
 acid. When the dextro- or laevo-acid is heated in a tube to 160 it is 
 converted into the inactive mandelic acid. 
 
 A direct transformation of the two active forms into each other is 
 accomplished as follows : With PC1 5 , d-mandelic acid gives 1-phenyl- 
 chloracetic acid, and this, with NH 3 , gives d-phenyl-alanin, which is 
 converted into 1-mandelic acid by means of HNO 2 (Walden's reversal, 
 Vol. I.). The transformation of 1-mandelic acid into the dextro-form 
 is done in a similar manner (C. 1909, II. 23). 
 
 Derivatives of Para-mandelic Acid. The methyl and ethyl esters 
 melt at 52 and 34 (B. 28, 259). Amide, m.p. 131 (B. 25, 2212). 
 Hydrazide, m.p. 132, gives, with HNO 2 , the very unstable azide, which, 
 in contrast with other carboxylic azides, decomposes with alcohol into 
 benzaldehyde, N 2 , and allophanic acid ester (B. 34, 2794). Methyl- 
 ether acid, m.p. 71. Dimethyl-ether ester, m.p. 246 (A. 220, 40). 
 Diethyl-ether ester, see C. 1899, II. 622. Aeetyl-mandelie acid, m.p. 
 80. Acetyl-mandelic chloride, b.p. 12 132 ; amide, m.p. 112 ; anilide, 
 m.p. 117-5; ethyl ester, m.p. 74 (A. 368, 57). 
 
 Mandelic chloralide, m.p. 82 (A. 193, 40). Diphenyl-glycolide 
 C 6 H 5 CH<^^^CHC 6 H 5 , m.p. 240, from mandelic acid in pyridin with 
 
 phosgene (B. 35, 3642). 
 
 Mandelic acid nitrile C 6 H 5 .CHOH.CN is a colourless oil, solidifying 
 at 10. At 170 it breaks down into prussic acid and benzaldehyde. 
 Like mandelic acid, the nitrile is also obtained in a laevo- and a dextro- 
 form, from which, by saponification and reversal, active mandelic 
 acids can be prepared. 
 
 On standing with fuming hydrochloric acid it passes into the 
 amide ; and, when heated, into phenyl-chloracetic acid (B. 14, 1967). 
 It condenses with benzaldehyde in different ways : by the action of 
 alcoholic dilute HC1 to C 6 H 5 CH[OCH(CN)C 6 H 5 ]2, and by the action of 
 etheric HC1 to diphenyl-oxazol and benzylidene-mandelic amide 
 C 6 H 5 CH : NCOCH(OH)C 6 H 5 (B. 29, 207, R. 791 ; 35, 1590). 
 
 Derivatives of mandelic acid are trichloro-methyl- and tribromo- 
 methyl-phenyl-carbinol CC1 3 CH(OH)C 6 H 5 , b.p. 25 155, and CBr 3 CH 
 (OH)C 6 H 5 , m.p. 78 ; these compounds are prepared, in a manner 
 
378 ORGANIC CHEMISTRY 
 
 analogous to acetone-chloroform, by combination of benzaldehyde 
 with CC1 3 H and CBr 3 H, by means of caustic potash, or by the action 
 of C 6 H 5 MgBr upon chloral ; they are convertible into mahdelic acid, 
 or, by reduction with zinc dust, into styrol and halogen styrols (C. 1900, 
 II. 326) ; on boiling with potassium carbonate they decompose into 
 CHC1 3 (or CHBr 3 ) and benzaldehyde (C. 1908, I. 1388). 
 
 p-Dimethyl-amido-phenyl-trichlor-ethyl alcohol (CH 3 ) 2 NC 6 H 4 CH 
 (OH)CC1 3 , from dimethyl-aniline and chloral (B. 19, 365) ; p-dimethyl- 
 amido-mandelie nitrile (CH 3 ) 2 N[ 4 ]C 6 H 4 CH(OH)CN, m.p. 114, from 
 p-dimethyl-amido-benzaldehyde (B. 35, 3571). 
 
 p-Bromo- and p-iodo-mandelic acids melt at 117 and 133 (B. 24, 
 997 ; 23, 3467). o-, m-, and p-Nitro-mandelic acids melt at 140, 119, 
 and 126 (B. 20, 2203 ; 22, 208). For a peculiar reduction product 
 of the latter, see B. 41, 373. 
 
 o-Amido-mandelic acid, hydrindic acid NH 2 [2]C 6 H 4 CH(OH)CO 2 H, 
 is not stable in a free condition. Its sodium salt C 8 H 8 NO 3 Na-fH 2 O is 
 formed in the reduction of isatin with sodium amalgam. From con- 
 centrated solutions of the sodium salt, acids separate. 
 
 Dioxindol, o-amido-mandelic acid lactame C 6 H 4 / [l ^^ (OH)( ] :O . This 
 
 L [2J.NH. 
 
 is also produced when isatin and zinc dust, water, and some hydro- 
 chloric acid are boiled. 
 
 Acetyl-dioxindol, melting at 127, is converted by baryta water into 
 o-acetamido-mandelie acid CH 3 CONH[2]C 6 H 4 CH(OH)CO 2 H, melting 
 at 142, which also results from the reduction of acetyl-isatinic acid. 
 Hydriodic acid or sodium amalgam change it to oxindol (p. 310). 
 
 o-Oxy-mandelic acid, obtained from salicyl-aldehyde, prussic acid, 
 and also from o-oxy-phenyl-glyoxylic acid, is a syrupy mass. An 
 optically active oxy-mandelic acid is formed from helicin tetra-acetate 
 with HCN and saponification (C. 1902, II. 214). Its lactone melts at 
 49 and boils at 237 (B. 14, 1317 ; 17, 974). p-Methoxy-mandelic 
 acid, from anisaldehyde, melts at 93 (B. 14, 1976). 2, 5-Dioxy- 
 mandelic acid, m.p. 143 with decomposition, by reduction of hydro- 
 quinone-glyoxylic acid. 
 
 Phenyl-chloracetie acid C 6 H 5 .CHC1.CO 2 H, melting at 78, is produced 
 when mandelic acid is heated with concentrated hydrochloric acid to 
 140 ; from trichloro-methyl-phenyl-carbinol with KHO (C. 1897, I. 
 1014) ; and by action of water upon its chloride. Its chloride C 6 H 5 . 
 CHC1.COC1, formed by the action of PC1 5 upon mandelic acid, boils at 
 125 (45 mm.) (A. 279, 122). 
 
 Phenyl-bromacetie acid C 6 H 5 .CHBrCO 2 H melts at 83. Its ethyl 
 ester, boiling at 145 (10 mm.) (B. 24, 1877), when heated with potassium 
 cyanide becomes diphenyl-succinic ester. Chloride, b.p. 18 118. Its 
 nitrile, from benzyl cyanide and bromine, when heated alone becomes 
 stilbene ; when heated with potassium cyanide it yields stilbene or 
 dicyano-dibenzyl (q.v.) ; while with alcoholic potash stilbene-dicar- 
 boxylic acid or diphenyl-maleic acid is produced. 
 
 Phenyl-nitro-aeetic ester and phenyl-nitro-aceto-nitrile are formed 
 as sodium salts C 6 H 5 C(NOONa)CO 2 C 2 H 5 and C 6 H 5 C(NOONa)CN from 
 phenyl-acetic ester and benzyl cyanide, with ethyl nitrate and sodium 
 alcoholate ; the free acids are very unstable ; saponification with NaHO 
 yields sodium-phenyl-nitro-methane and reduction of sodium-phenyl- 
 
PHENYL-PARAFFIN ALCOHOL ACIDS 379 
 
 nitro-acetonitrile, with zinc dust, yields iso-nitroso-benzyl cyanide 
 C 6 H 5 C(NOH)CN (B. 35, 1755 ; 42, 1930). 
 
 Phenyl-amido-acetic acid C 6 H 5 .CH(NH 2 ).CO 2 H melts at 256. It 
 yields CO 2 and benzyl-amine when it is distilled. It results (i) on 
 treating phenyl-bromo-acetic acid with aqueous ammonia (B. 11, 2002) ; 
 
 (2) on boiling its nitrile with dilute sulphuric acid (B. 13, 383) ; and 
 
 (3) by the reduction of its oxime or the phenyl-hydrazone of benzoyl- 
 formic acid (A. 227, 344). 
 
 By means of d-camphor-sulphonic acid, or by decomposition of the 
 formyl compound, m.p. 180, with cinchonin or quinine, phenyl- 
 amido-acetic acid has been split up into its optically active components 
 with coefficient 157-8. The 1-acid is also formed on partial fermenta- 
 tion of the racemic acid with yeast (B. 41, 1286, 2071). Its methyl ester 
 melts at 32. Cyclic double-acid amide C 6 H 5 .CH<^~^^)>CH.C 6 H 5 
 
 melts with decomposition at 274 (B. 24, 4149). Its nitrile is a yellow 
 oil, which gradually solidifies to a crystalline mass. It is very decom- 
 posable. It results from the action of ammonia upon mandelic nitrile. 
 
 Alkylic and phenylated phenyl-amido-acetic acids are obtained as 
 the result of the action of methyl-amine, aniline, and similar bases 
 upon phenyl-bromo-acetic acid (B. 15, 2031). Starting from phenyl- 
 bromo-acetic chloride, a number of di- and poly-peptides, like phenyl- 
 glycyl-glycin, phenyl-glycyl-alanin, etc., have been prepared (A. 
 340, 190). 
 
 a-Anffido-phenyl-acetic nitrite C 6 H 5 CH(NHC 6 H 5 )CN, m.p. 85, is 
 easily obtained from benzylidene-aniline and prussic acid, as well as 
 from mandelic acid nitrile with aniline ; on boiling with alcoholic 
 potash, it combines with benzaldehyde to form the benzylidene compound 
 of the corresponding acid amide : 
 
 C 6 H 5 CH(NHC 6 H 5 )CN+C 6 H 5 CHO=C 6 H 5 CH(NHC 6 H 5 )CON : CHC 6 H 5 . 
 
 The latter substance is very stable, and is also formed by the action 
 of KCN upon a mixture of benzylidene-aniline and benzaldehyde 
 (B. 31, 2699). p-Dimethyl-amido-phenyl-anilido-aceto-nitrile (CH 3 ) 2 
 NC 6 H 4 CH(NHC 6 H 5 )CN, m.p. 114 (B. 35, 3572)- 
 
 Urethano-phenyl-aceto-nitrile C 6 H 5 CH(NHCO 2 C 2 H 5 )CN, m.p. 83, 
 from mandelic acid nitrile with urethane and zinc chloride (B. 34, 370). 
 
 Of the alphyl-glycollic acids, mention may yet be made of p-iso- 
 propyl-mandelie acid, prepared from cumic aldehyde, prussic acid, and 
 hydrochloric acid. It, too, has been resolved by means of quinine into 
 its active isomerides (B. 26, R. 89). 
 
 Phenyl-oxy-propionic Acids, Phenyl-lactic Acids. There are four 
 possible structural isomerides. All are known, and contain an asym- 
 metric carbon atom : 
 
 C0 2 H C0 2 H C0 2 H C0 2 H 
 
 C 6 H 5 .COH CHOH C,H 5 .CH CH 2 
 
 CH 3 C 6 H 5 .CH 2 CH 2 .OH C 6 H 5 .CHOH 
 
 a- Phenyl-lactic acid, jS-Phenyl-lactic a-Phenyl-hydracrylic acid, jS-Phenyl-hydra- 
 atro-lactinic acid acid tropaic acid crylic acid. 
 
 i. Atro-lactinie acid, a-phenyl-lactic acid C 9 H 10 O 3 +iJH 2 O, melts 
 when in the hydrous state at 90, and when anhydrous at 94. It is 
 
380 ORGANIC CHEMISTRY 
 
 obtained from a-bromo-hydro-atropic acid when the latter is boiled with 
 a soda solution, from hydratropic acid with KMnO 4 , from its nitrile, 
 the addition product of prussic acid on aceto-phenone, by boiling 
 with dilute HC1 (B. 14, 1980) ; its ethyl ester, b.p. 259, is also formed 
 from phenyl-glyoxylic ester with methyl-magnesium iodide. When 
 boiled with concentrated hydrochloric acid it decomposes into water 
 and atropic acid. 
 
 Corresponding to atro-lactinic acid are a-chloro- and a-bromo-hydra- 
 tropic acids, melting at 73 and 93, which are produced when it stands 
 in contact with concentrated haloid acids (A. 209, 3). a-Amido-hydra- 
 tropic acid sublimes, without melting, at 260 (B. 14, 1981). 
 
 2. Tropic acid, a-phenyl-hydr aery lie acid, is known in an inactive, 
 decomposable, and two optically active modifications. 
 
 Inactive tropic acid, melting at 117, is obtained, together with 
 tropine (q.v.) (A. 138, 233 ; B. 13, 254), on digesting (60) the alkaloids 
 atropine and hyoscyamine with baryta water. It was made syntheti- 
 cally from atropic acid, the decomposition product of atro-lactinic acid, 
 by changing it with concentrated hydrochloric acid into jS-chloro- 
 hydratropic acid, which boiling potassium carbonate converts into 
 inactive tropic acid : 
 
 CO 2 H CO 2 H CO 2 H CO 2 H 
 
 C 6 H 5 .COH > C 6 H 5 .C --* C 6 H 5 .CH -^~-> C 6 H 5 .CH 
 
 CH 3 CH 2 CH 2 C1 CH 2 OH 
 
 Atro-lactinic acid Atropic acid /?-Chl6ro-hydra tropic acid Tropic acid. 
 
 Lsevo- and dextro-tropic acids, melting at 128 and 123, can be 
 separated by the fractional crystallisation of their quinine salts, and 
 are thus prepared from r-tropic acid. The dextro-quinine salt, more 
 sparingly soluble in dilute alcohol, melts at 186, and the laevo-salt at 
 178 (B. 22, 2591). 
 
 j8-Chloro- and jS-bromo-hydratropie acids melt at 87 and 93. 
 
 j8-Amido-hydratropic acid melts at 119 (A. 209, 3). 
 
 3. j3-Phenyl-lactic acid, benzyl-glycollic acid C 6 H 5 .CH 2 .CH.(OH). 
 CO 2 H, melting at 97, is derived from phenyl-acetaldehyde, with 
 prussic acid and hydrochloric acid, and from benzyl-tartronic acid upon 
 heating it to 180. Heated with dilute sulphuric acid, it decomposes 
 into phenyl-acetaldehyde and formic acid. 
 
 a-Bromo-hydro-cinnamie acid C 6 H 5 CH 2 .CHBr.COOH, m.p. 49, 
 is formed from benzyl-malonic acid by bromi nation and CO 2 elimina- 
 tion. Chloride, b.p. 12 133 (B. 39, 3999). 
 
 Phenyl-alanin, J3-phenyl-a-amido-propionic acid C 6 H 5 . CH 2 . CH 
 (NH 2 ).CO 2 H sublimes without decomposition when it is slowly heated. 
 Upon rapid heating it yields phenyl-ethyl-amine and a cyclic double- 
 acid amide C 6 H 5 .CH 2 .CH./^9;^\CH.CH 2 .C 6 H 5 , m.p. 290 (A. 219, 
 
 \.N J~l.V_xV_// 
 
 188 ; 271, 169). It is found along with asparagin in the sprouts 
 of Lupinus luteus, and is formed in the decay, or by the chemical de- 
 composition, of albumen, casein, or gelatin, and can be separated out 
 from mixtures by means of its sparsely soluble phospho-tungstate 
 compound (C. 1902, II. 272). Synthetically, the optically inactive form 
 is prepared from its nitrile, the product of the action of ammonia upon 
 the nitrile of jS-phenyl-lactic acid, with hydrochloric acid ; further, 
 
PHENYL-PARAFFIN ALCOHOL ACIDS 381 
 
 by the reduction of a-amido-cinnamic acid (B. 17, 1623), and of a-iso- 
 nitroso-/3-phenyl-propionic acid (A. 271, 169). Also from phthal- 
 imido-benzyl-malonic ester C 6 H 4 (CO) 2 NC(CH 2 C 6 H 5 )(COOR) 2 by split- 
 ting (C. 1903, II. 33) and by the action of NH 3 upon a-bromo-hydro- 
 cinnamic acid. From the inactive phenyl-alanin thus obtained, the 
 d- and 1-bodies of rotation coefficient 35 are obtained by partial fer- 
 mentation with yeast, or by breaking up the formyl compound with 
 brucin (A. 357, 2 ; C. 1908, I. 1632). 
 
 Benzoyl-phenyl-alanin, from benzoyl-amido-cinnamic acid by re- 
 duction, melts at 182 (A. 275, 15). 
 
 Phenaeetyl-phenyl-alanin C 6 H 5 CH 2 CH(NHCOCH 2 C 6 H 5 )COOH, m.p. 
 126, is obtained in the same way ; and also by a peculiar reaction 
 of ammonia with phenyl-pyro-racemic acid (A. 307, 146). Phenyl- 
 alanin-ethyl ester, b.p. 10 143 (C. 1901, 1. 679). 
 
 A considerable number of di- and polypeptides containing the phenyl- 
 alanin complex, like phenyl-alanyl-glycin, phenyl-alanyl-phenyl-alanin, 
 and leucyl-glycyl-phenyl-alanin, have been obtained by the methods 
 described in Vol. 1., starting from active and inactive phenyl-alanin 
 or from a-bromo-hydro-cinnamic chloride (A. 354, I ; 357, i). 
 
 o- and p-Nitro-phenyl-laetie acids are produced in the nitration 
 of phenyl-lactic acid. When reduced the o-acid yields oxy-hydro- 
 
 r[i]CH 2 CH.OH 
 
 carbo-styril C 6 H 4 { , m.p. 197, and the p-acid, p-amido- 
 
 H2JNH CO 
 
 jS-phenyl-lactie acid NH 2 [ 4 ]C 6 H 4 .CH 2 .CH(OH)CO 2 H, melting with 
 decomposition at 188. 
 
 o-Oxy-plienyl-lactic acid, salicyl-lactic acid HO[2]C 6 H 4 CH 2 CH 
 (OH)CO 2 H, is a syrup -like mass. It results from the action of 
 sodium amalgam upon o-oxy-phenyl-pyro-racemic acid (B. 18, 1188). 
 Its inner phenol - alcohol anhydride is hydro - eumarilic acid 
 
 /-[i]CH 2 .CH.CO 2 H 
 C 6 HJ ' , melting at 118. This is the reduction pro- 
 
 \[2]o ! 
 
 duct of eumarilic acid (A. 216, 166). p-Oxy-phenyl-lactic acid 
 melts at 144 in the anhydrous condition. It is formed when an excess 
 of nitrous acid acts upon p-amido-phenyl-alanin (A. 219, 226). 
 
 2, 4-Dioxy-phenyl-laetie acid, hydroquinone lactic acid, m.p. 87, see 
 C. 1907, II. 901. p-Iodo-phenyl-alanin, m.p. 270 with decomposition 
 (see C. 1909, I. 70 ; B. 42, 3411). 
 
 p-Nitro- phenyl-alanin NO 2 [4]C 6 H 4 CH 2 .CH(NH 2 )CO 2 H decom- 
 poses at 240. It is formed in the nitration of phenyl-alanin. 
 
 p-Amido-phenyl-alanin NH 2 [4]C 6 H 4 .CH 2 .CH(NH 2 ).CO 2 H is pro- 
 duced in the reduction of p-nitro-phenyl-alanin and p-nitro-phenyl- 
 a-nitro-acrylic acid. 
 
 Tyrosin, p-oxy- phenyl - alanin HO[4]C 6 H 4 .CH 2 CH(NH 2 )CO 2 H, 
 melts at 235. It occurs in the liver when its functions are disturbed, 
 the spleen, the pancreas, and in stale cheese (rvpos), and is formed 
 from animal substances (urea, horn, hair, albumen) on boiling them 
 with hydrochloric or sulphuric acid ; by fusion with alkalies or by 
 putrefaction (together with leucine, aspartic acid, etc.). It may be 
 prepared synthetically from p-amido-phenyl-alanin by the action of 
 one molecule of potassium nitrite upon the hydrochloric acid salt, or 
 by splitting up synthetic benzoyl-tyrosin. 
 
382 ORGANIC CHEMISTRY 
 
 History. Liebig discovered tyrosin upon fusing freshly prepared 
 cheese with caustic potash (1846) (A. 57, 127 ; 62, 269). E. Erlen- 
 meyer, sen., and Lipp (A. 219, 161) succeeded in synthesising tyrosin, 
 beginning with phenyl-acetaldehyde. 
 
 Synthesis of Tyrosin. Phenyl-acetaldehyde and prussic acid yield 
 the nitrile of phenyl-lactic acid. Ammonia changes the latter to the 
 nitrile of phenyl-alanin, which hydrochloric acid converts into phenyl- 
 alanin. The latter by nitration yields p-nitro-phenyl-alanin, whose 
 reduction product, p-amido-phenyl-alanin hydrochloride, is changed 
 by an equimolecular quantity of nitrous acid into tyrosin : 
 
 CN CN CO 2 H CO 2 H CO 2 H CO 2 H 
 
 CHO CHOH CHNH 2 CHNH 2 CHNH 2 CHNH 2 CH.NH 2 
 CH 2 CH 2 CH 2 CH 2 CH 2 "*" CH 2 CH 2 
 
 C 6 H 5 C 6 H 5 C 6 H 5 C 6 H 5 C 6 H 4 [ 4 ]N0 2 i 6 H 4 [ 4 ]NH 2 C 6 H 4 [ 4 ]OH 
 
 Phenyl- Nitrile Amido- Phenyl- p-Nitro- p-Amido- Tyrosin. 
 
 acetalde- of phenyl-lac- alanin phenyl- phenyl- 
 
 hyde phenyl- tic acid alanin alanin 
 lactic acid nitrile 
 
 A more convenient method has recently been found by E. Erlen- 
 meyer, jun. (see A. 307, 138 ; B. 32, 3638). 
 
 Properties and Behaviour.- It dissolves in 150 parts of boiling water, 
 and crystallises in delicate, silky needles. It dissolves in alcohol with 
 difficulty, and is insoluble in ether. 
 
 Mercuric nitrate produces a yellow precipitate, which becomes dark 
 red in colour if it be boiled with fuming nitric acid to which consider- 
 able water has been added (delicate reaction). Being an amido-acid, 
 tyrosin unites with acids and bases, forming salts. If it be heated to 
 270 it decomposes into carbon dioxide and oxy-phenyl-ethyl-amine 
 C 6 H 4 (OH).CH 2 .CH 2 .NH 2 . When fused with caustic potash it yields 
 para-oxy-benzoic acid, ammonia, and acetic acid. Putrefaction causes 
 the formation of hydro-para-cumaric acid, and nitrous acid converts the 
 tyrosin into para-oxy-phenyl-lactic acid (A. 219, 226). Many di- and 
 polypeptides have been formed by the combination of active and in- 
 active tyrosin with other amido-acids (B. 41, 2840, 2860). By analyti- 
 cal methods also, such as the hydrolysis of silk fibroin with HC1, a 
 dipeptide containing the tyrosin complex, glycyl-ty rosin, as well as a 
 tetrapeptide, have been isolated (B. 40, 3544). 
 
 Very noteworthy is the natural occurrence of inactive 3, 5-di-iodo- 
 tyrosin OH[4]I 2 [3, 5]C 6 H 2 CH 2 .CH(NH 2 ).CO 2 H, m.p. 213, first ex- 
 tracted from the coral Gorgonia Carolinii (C. 1896, I. 864), and hence 
 called iodogorgic acid. Synthetically, it has been prepared by iodina- 
 tion of tyrosin in alkaline solution (C. 1905, I. 1388). On polypeptides 
 with 3, 5-di-iodo-l-tyrosin, see B. 41, 1237. 
 
 4. j8-Phenyl-hydraerylic acid C 6 H5.CH(OH).CH 2 .CO 2 H, commonly 
 called phenyl-lactic acid, results on boiling jS-bromo-hydro-cinnamic acid 
 with water (A. 195, 138), and in the reduction of benzoyl-acetic ester, 
 as well as by the addition of hypochlorous acid to cinnamic acid, and 
 then reducing the resulting chloro-acid with sodium amalgam. The 
 acid melts at 93. When heated with dilute sulphuric acid it decom- 
 poses (like the aliphatic j8-oxy-acids) at 190 into water and cinnamic 
 
PHENYL-PARAFFIN ALCOHOL ACIDS 383 
 
 acid (together with a little styrol) (B. 13, 304). When digested with 
 concentrated haloid acids it forms j8-halogen-hydro-cinnamic acids (q.v.). 
 a- and /3-Alkylated jS-phenyl-hydracrylic acids have been obtained by 
 the action of a-bromo-aliphatic acid esters, and zinc, upon benzaldehyde 
 and aromatic a-ketones. 
 
 a-Methyl-^-phenyl-ethylene - lactic acid C 6 H 5 CH(OH)CH(CH 3 ) 
 COOH, m.p. 95. a-Dimethyl-/?, p-tolyl-ethylene-laetie acid, m.p. 112. 
 a-Iso-propyl-phenyl-ethylene-lactic acid, m.p. 107 (C. 1898, I. 668, 
 884; 1900, II. 533; 1902, I. 1293; 1903, II. 566 ; B. 40, 1589 ; 41, 5). 
 
 o-, m-, and p-Nitro-phenyl-laetic acids, or -hydr acrylic acids NO 2 . 
 C 6 H 4 CH(OH).CH 2 .C0 2 H, melt at 126, 105, and 132. The three iso- 
 merides result upon treating the three nitro-jS-bromo-hydro-cinnamic 
 acids with sodium carbonate, when (in the cold) the 0-, m-, and p-nitro- 
 
 O CO 
 phenyl-lactic acid lactones, I , melting at 124, 98, and 
 
 N0 2 C 6 H 4 CH.CH 2 
 
 92, are also produced. These are the only fi-lactones known (B. 17, 
 595, 1659). 
 
 The ortho-nitro-acid results, further, by oxidising the aldehyde first 
 produced with silver oxide (B. 16, 2206). When heated to 190 with 
 dilute sulphuric acid it yields o-nitro-cinnamic acid. Its lac tone de- 
 composes on boiling with water into carbon dioxide and o-nitro-styrol ; 
 it yields /?-oxy-hydro-carbo-styrol when reduced. 
 
 /2-Chloro-, bromo-, and iodo-hydro-cinnamie acids C 6 H 5 .CHX.CH 2 . 
 CO 2 H melt at 126, 137, and 120. They are obtained from cinnamic 
 acid or /3-phenyl-acrylic acid by the addition of halogen hydrides in 
 aqueous or glacial acetic acid solution (B. 11, 1211) and from j8-phenyl- 
 hydracrylic acid (q.v.). When heated or boiled with water the free 
 acids decompose, with previous formation of j8-oxy-acids, into halogen 
 hydride and cinnamic acid. When neutralised, even in the cold, with 
 alkali carbonates they break down into haloid acid, carbon dioxide, 
 and styrol C 6 H 5 .CH : CH 2 . 
 
 o-, m-, and p-Nitro-j8-bromo-hydro-einnamie acids NO 2 C 6 H 4 CHBr. 
 CH 2 .CO 2 H are produced by the addition of hydrogen bromide, in 
 glacial acetic acid, to the three nitro-cinnamic acids (B. 17, 596, 1494) 
 (see also Nitro-phenyl-lactic acid lactone) . 
 
 jS-Hydroxylamin6-hydro-cinnamicacidC 6 H 5 CH(NHOH).CH 2 COOH, 
 m.p. 166 with decomposition, is formed by the attachment of free 
 hydroxylamine to cinnamic acid. By oxidation with ammoniacal 
 silver solution it becomes y-phenyl-isoxazolone (q.v.), and with HNO 2 
 it becomes N-oxy-y-phenyl-isoxazolidone (B. 39, 3115). On reduction 
 it forms : 
 
 j3-Amido-hydro-einnamie acid C 6 H 5 .CH(NH 2 )CH 2 .CO 2 H melts at 
 131, which with HNO 2 yields j8-phenyl-hydracrylic acid (B. 38, 2316). 
 
 y-Phenyl-a-amido-butyrie acid C 6 H 5 CH 2 .CH 2 CH(NH 2 )COOH, m.p. 
 295, by reduction of benzyl-pyro-racemic acid oxime (B. 39, 1478). 
 
 y- and 8-Oxy-acids. y-Oxy-acids, beginning with the phenyl- 
 oxy-butyric acids, are known. They pass readily into their lactones. 
 y-Phenyi-y-oxy-butyrie acid C 6 H 5 CH(OH).CH 2 .CH 2 .CO 2 H melts at 
 75, and slowly decomposes, even at 65-7O, into water and its 
 lactone, phenyl-butyro-Iaetone C 10 H 10 O 2 . The latter melts at 37 and 
 boils at 306. 
 
 It is obtained from jS-benzoyl-propionic acid (B. 15, 889) and from 
 
384 ORGANIC CHEMISTRY 
 
 phenyl-bromo-butyric acid. Its lactone is formed on boiling phenyl- 
 iso-crotonic acid and phenyl-paraconic acid with dilute sulphuric acid 
 (A. 228, 178 ; B. 29, R. 14 ; 33, 3519). 
 
 On the relations of m-tolyl-butyro-lactoneCH 3 C 6 H 4 CHCH 2 CH 2 Co6 
 towards cannabinol, the poisonous resin of Indian hemp, Cannabis 
 indica, see C. 1899, I. 118. 
 
 a-Phenyl-y-oxy-valeric acid, only stable in the form of liquid 
 lactone (B. 17, 73). 
 
 y-Phenyl-y-valero-lactone, b.p. 16 169 (C. 1902, II. 1359). 
 
 8-Benzyl-y-oxy-valeric acid melts at 101, and its lactone at 33 
 (A. 268, 94). 
 
 j3-Benzyl-y-oxy-valeric acid melts at 75, and its lactone at 86 
 (A. 254, 215). It is obtained from benzal-laevulinic acid. 
 
 a-Benzyl-S-oxy- valeric acid (B. 24, 2447). 
 
 B. Dioxy-aleohol Acids are chiefly obtained by oxidising the phenyl- 
 olefin-carboxylic acids with potassium permanganate (A. 268, 44 ; 
 283, 338). The two possible phenyl-gly eerie acids are known. 
 
 Atro-glyceric acid, a-phenyl-glyceric acid CH 2 OH.C(C 6 H 3 )OH. 
 CO 2 H, melting at 146, results on boiling a, j3-dibromo-hydratropic 
 acid with excess of alkalies, and, from benzoyl-carbinol, by means of 
 prussic acid and hydrochloric acid (B. 16, 1292). It breaks down into 
 CO 2 and phenyl-acetaldehyde upon heating. 
 
 Dibromo-hydratropie acid CH 2 Br.C(C 6 H 5 )Br.CO 2 H, melting at 
 115, is produced when bromine acts upon atropic acid. It decom- 
 poses on boiling with water into aceto-phenone, CO 2 , and HBr. 
 
 Styceric acid, j3-phenyl-glyceric acid C 6 H 5 .CHOH.CHOH.COOH, 
 contains two unsym. carbon atoms, and therefore occurs in different 
 modifications. An acid of m.p. 121 is obtained by saponification with 
 alcoholic potash from its dibenzoyl-ethyl ester C 6 H 5 CH(OCOC 6 H 5 )CH 
 (OCOC 6 H 5 )COOC 2 H 5 , m.p. 109, the result of the action of silver benzo- 
 ate upon cinnamic ester dibromide ; on saponifying the dibenzoyl ester 
 with aqueous alkaline hydroxide an acid is formed, melting at 141 
 with decomposition, which is also obtained by the oxidation of 
 cinnamic acid with KMnO 4 . It dissolves in ether with difficulty, and 
 yields on the gradual benzoylation of its ethyl ester a dibenzoyl ester 
 of m.p. 85, while benzoylation at a higher temperature produces 
 transposition into an ester of m.p. 109. The m.p. 121 acid is 
 racemic, and may be split up into two optical antipodes by means 
 of the stycerin salt, a- and 1-styceric acid, m.p. 167, a D =+3i-o8 
 and 30-23 respectively, while the m.p. 141 acid has not hitherto 
 been so split up (B. 30, 1600). It is significant that oxidation of 
 the ordinary fumaroid cinnamic acid with KMnO 4 yields the m.p. 
 141 acid, while the maleiinoid allo-cinnamic acid yields the m.p. 121 
 acid (B. 41, 2411). On heating above their melting-points, the acids 
 break up into CO 2 and phenyl-acetaldehyde. On warming with H 2 SO 4 , 
 concentrated HC1, or acetic anhydride water, is split off and phenyl- 
 pyro-racemic acid formed (B. 43, 1032). With HBr the m.p. 121 acid 
 gives a phenyl-jS-bromo-a-oxy-propionic acid of m.p. 157, while the 
 other gives a bromoxy-acid of m.p. 165. 
 
 Benzal-phenyl-glyceric ester c H H ____CH co c H is P r duced 
 
PHENYL-PARAFFIN ALCOHOL ACIDS 3^5 
 
 In two stereo-isomeric forms, melting at 104 and 61 respectively, 
 by the action of diazo-acetic ester upon benzaldehyde. The benzal- 
 phenyl-glyceric acids, m.p. 132 and 156 respectively, are split up by 
 acetic acid into benzaldehyde and the phenyl-glyceric acids, m.p. 
 121 and 141. The latter, on shaking up with benzaldehyde and 
 50 per cent. H 2 SO 4 , regenerates the benzal-phenyl-gly eerie acid; m.p. 
 156 (B. 43, 1024). 
 
 p-Nitro-phenyl-glyceric acid, melting at 167, is obtained from 
 p-nitro-phenyl-glycidic acid. 
 
 o-Amido-phenyl-glycerie acid, m.p. 218. 
 
 Phenyl-a-chloro--laetie acid C 6 H 5 .CH(OH)CH.C1.CO 2 H+H 2 
 melts at 56, and, when anhydrous, at 86. It results from the action 
 of hypochlorous acid upon cinnamic acid. Sodium amalgam reduces 
 it to phenyl-lactic acid, alkalies change it to phenyl-glycidic acid and 
 phenyl-glyceric acid, while, with fuming hydrochloric acid, it yields 
 phenyl-dichloro-propionic acid (B. 22, 3140). 
 
 Phenyl-a-bromo-jS-lactie acid C 6 H 5 .CH(OH).CHBr.CO 2 H+H 2 O 
 melts at 125 when anhydrous. It is formed on boiling phenyl-dibromo- 
 propionic acid with water (B. 13, 310). It has been separated, by means 
 of cinchonin, into two optically active components (B. 24, 2831 ; 
 32, 2375). 
 
 Phenyl-a-iodo--laetie acid C 6 H 5 .CH(OH).CHI.CO 2 H melts at 137 
 with decomposition. It results from the action of an aqueous chloro- 
 iodine solution upon cinnamic acid (B. 19, 2464). o- and p-Nitro- 
 phenyl-a-chloro-lactic acids melt at 119 and 165. The o- body is 
 converted by sodium amalgam into indol (B. 13, 2261 ; 19, 2646). 
 
 -Phenyl-a-amido-hydracrylic acid, phenyl-serin C 6 H 5 .CH.(OH). 
 CH(NH 2 ).CO 2 H+H 2 O, decomposing at 194, is formed from its 
 benzylidene compound, the condensation product of benzaldehyde 
 and glycocoll, obtained with NaHO and acids, besides a more 
 soluble stereo-isomeric acid (A. 307, 84). 
 
 The isomeric j8-phenyl-j8-amido-laetie acid, phenyl-iso-serin C 6 H 5 
 CH(NH 2 ).CH(OH).CO 2 H, m.p. 241 with decomposition, is obtained 
 by the attachment of NH 3 to sodium in the cold (B. 39, 791). 
 
 j8-Phenyl-jS-ehloro-a-oxy-propiomc acid C 6 H 5 .CHC1.CH(OH).CO 2 H, 
 m.p. 141, and phenyl-jS-bromo-a-oxy-propionic acid are obtained from 
 phenyl-glyceric acid with fuming halogen hydrates (B. 16, 1290). 
 
 o- and p-Nitro-phenyl-/?-ehloro-laetic acids, melting at 125 and 167, 
 are obtained by the action of fuming hydrochloric acid upon the corre- 
 sponding glycidic acids (B. 19, 2646). 
 
 o-Nitro-phenyl-j8-bromo-lactie acid melts at 135 (B. 17, 221). 
 
 Cinnamic acid diehloride, a, f$-dichloro-hydro-cinnamic acid C 6 H 5 . 
 CHC1.CHC1.CO 2 H, melting at 163, results when chlorine acts upon 
 cinnamic acid in carbon disulphide solution and on treating phenyl-a- 
 chloro-lactic acid with fuming hydrochloric acid (B. 14, 1867). 
 
 Allo-cinnamic acid diehloride is an oil decomposable by strychnine 
 into two optically active components (B. 27, 2041). 
 
 Ginnamic acid dibromide, a, fi-dibromo-hydro-cinnamic acid, melting 
 at 195, yields CO 2 , phenyl-acetaldehyde, cinnamic acid, and phenyl-a- 
 bromo-lactic acid on boiling with water. Strychnine resolves it into 
 two optically active components (B. 26, 1664). The methyl ester melts 
 at 117. The ethyl ester melts at 69 (B. 22, 1181 ; C. 1903, II. 115). 
 
 VOL. II. 2 C 
 
386 ORGANIC CHEMISTRY 
 
 Allo-cinnamie aeid dibromide melts^at 9i-93. It is separated into 
 two optically active components by cinch onin (B. 27, 2039). The 
 methyl ester melts at 52-53. 
 
 o- and p-Nitro-a, jS-dibromo-hydro-cinnamic aeids melt at 180 and 
 227. The o- and p-ethyl esters melt at 71 and 110 (A. 212, 151). 
 
 o-Methoxy-einnamie aeid dibromide, m.p. 170 ; piper onyl aeid 
 dibromide, m.p. 156. In these dibromides the Br atom adjoining the 
 phenyl nucleus is very reactive (B. 39, 27 ; 40, 2174). 
 
 Phenyl-glyeidic aeid c H ^jJ^ H co H , separated from the sodium 
 
 salt, is an oil solidifying at o. It results from the action of alkalies 
 upon a- and jS-chloro-phenyl-lactic acids, as well as by the condensa- 
 tion of benzaldehyde with chloracetic ester (A. 271, 137). Phenyl- 
 glyeidic acid is very unstable. It readily decomposes into CO 2 and 
 phenyl-acetaldehyde. On boiling with water phenyl-glyceric acid is 
 also produced. Hot concentrated HC1 partly converts phenyl-glycidic 
 acid into the isomeric phenyl-pyro-racemic acid (B. 33, 3001). From 
 the optically active phenyl-a-bromo-lactic acids the optically active 
 phenyl-glycidic acids are obtained in the form of their sodium salts. 
 
 Numerous homologous phenyl-glycidic esters have been obtained 
 by condensation of aromatic aldehydes and ketones with chloracetic 
 ester, or chloro-propionic ester, by means of Na ethylate or amide 
 (C. 1905, I. 346 ; 1906, I. 669 ; B. 38, 699). The free acids obtained 
 by saponification, like the phenyl-glycidic acid itself, easily splits up 
 into CO 2 and aldehydes or ketones. /2-Methyl- and ethyl-phenyl- 
 glyeidie ethyl ester, b.p. 148 and 149. a-Methyl-phenyl-glycidie 
 ethyl ester, b.p. 18 153. 
 
 o-Nitro-phenyl-glycidie acid NO 2 [2]C 6 H 4 CH/^\CH.CO 2 H+H 2 O melts 
 at 94, and at 125 when anhydrous. It is produced when alcoholic 
 potash acts upon o-nitro-phenyl-lactic acid, or by the action of sodium 
 hypochlorite upon o-nitro-phenyl-lactic acid ketone (A. 284, 135). It 
 breaks down, on heating, into CO 2 and indigo. It yields anthranile 
 and anthroxan-aldehyde on boiling with water (B. 19, 2649). 
 
 Phenyl-a-oxy-butyro-lactone C 6 H 5 CH.CH 2 .CH(OH)COO, m.p. 125, 
 from benzoyl-pyro-racemic acid by reduction with Na amalgam, is 
 transformed into j8-benzoyl-propionic acid by boiling with dilute 
 HC1 (B. 35, 3767). 
 
 C. Trioxy-alcohol Aeids. y -Phenyl- trio xy- butyric acid C 6 H 5 
 [CH.OH] 3 CO 2 H passes readily into the lactone, melting at Ii5-ii7 ; 
 by reduction this yields phenyl-tetrose. y-Phenyl-trioxy-butyric acid 
 is prepared by starting with the dibromide of cinnamic aldehyde 
 cyanhydrin (B. 25, 2556 ; A. 319, 206). 
 
 (7) PHENYL-PARAFFIN-ALDEHYDE-CARBOXYLIC ACIDS. 
 
 As explained under the aliphatic unsaturated ketols, oxy-olefin- 
 carboxylic acids and oxy-ketone-carboxylic acids, the oxy-methylene 
 derivatives are produced by the condensation of acetone, acetic ester, 
 aceto-acetic ester, and other bodies with formic ester in the presence 
 of sodium ethylate. As these compounds conduct themselves in many 
 respects like aldehydes, it was originally supposed that they contained 
 
PHENYL-PARAFFIN-KETONE-CARBOXYLIC ACIDS 387 
 
 the aldehyde group, and it was only their very pronounced acid char- 
 acter which led to considering them as oxy-methylene compounds. It 
 is rather remarkable that two isomeric esters are formed in the con- 
 densation of phenyl-acetic ester and formic ester by means of sodium 
 ethylate. Both bodies yield the same derivatives with phenyl-hydrazin. 
 The one is a liquid and the other a solid. 
 
 Both forms, especially when dissolved, can quite easily be converted 
 into each other. The liquid form is that of the metallic compounds, 
 and is distinguished from the solid form by the strong blue-violet 
 colour produced by ferric chloride. It also reacts more easily with 
 phenyl cyanate. It is assumed that the liquid form corresponds to 
 the enol form of formyl-phenyl-acetic ester, and the solid form to the 
 aldo form of the same (W. Wislicenus, A. 312, 34 ; also B. 39, 203). 
 
 Oxy-methylene-phenyl-acetie ethyl ester CH(OH) : C(C 6 H 5 )CO 2 C 2 H 5 
 is a liquid boiling at 144 (16 mm.). Ferric chloride imparts a violet 
 colour to it. Its sodium compound gives, with benzoyl chloride, 
 a liquid, unstable a-benzoate CH(OCOC 6 H 5 ) : CH(C 6 H 5 )CO 2 C 2 H 5 , which 
 is converted, on distillation, into a geometrically isomeric stable 
 jS-benzoate, m.p. 88. Methyl ester, m.p. 41. 
 
 Phenyl-formyl-aeetie ethyl ester CHO.CH(C 6 H 5 )CO 2 C 2 H 5 melts at 
 70, passing at the same time into the liquid isomeric ester. Methyl 
 ester, m.p. 73 (C. 1900, I. 122). 
 
 (8) PHENYL-PARAFFIN-KETONE-CARBOXYLIC ACIDS. 
 
 The acids belonging to this group can be arranged, like the aliphatic 
 ketone-carboxylic acids, as a-, /?-, and y-ketone-carboxylic acids, and 
 in each of these groups we can have sub-groups, depending upon whether 
 the ketone group is in direct union with the benzene nucleus or not. 
 
 A. a-Ketone-carboxylie Acids result from the oxidation (i) of 
 ketones ; (2) of glycols ; (3) of ketone alcohols ; (4) of alcohol-car- 
 boxylic acids ; (5) (nuclear synthetic) from cyanides of the acid 
 radicles by saponification with cold concentrated hydrochloric acid ; 
 (6) from benzenes by the action of chloroxalic esters in the presence of 
 aluminium chloride (B. 20, 2045 ; C. 1898, I. 26, 42). 
 
 Phenyl-glyoxylic acid, benzoyl-formic acid C 6 H 5 .CO.CO 2 H, melting 
 at 65, and isomeric with the phthal-aldehydic acids, is obtained by 
 oxidising aceto-phenone with potassium ferricyanide (B. 20, 389), as 
 well as by oxidising phenyl-glycol, benzoyl-carbinol, and mandelic acid 
 with nitric acid : 
 
 C 6 H 5 CO.CH 3 -x C-H.COCOOH / C 6 H 5 CO.CH 2 OH 
 
 C 6 H 5 CH(OH).CH 2 OH -/ \ C 6 H 5 CH(OH)CO 2 H 
 
 The acid was first prepared (by nuclear synthesis) by saponifying 
 benzoyl cyanide, its nitrile, obtained from benzoyl chloride and 
 mercury, or silver cyanide (Claisen). Its ethyl ester is formed when 
 ethyl-chloroxalic ester acts upon mercury diphenyl or upon benzene 
 in the presence of A1C1 3 . 
 
 The acid is very soluble in water, and, when distilled, decomposes 
 into CO and benzoic acid, with a small division into CO 2 and benz- 
 aldehyde. Heating with aniline splits it up into CO 2 and benzylidene- 
 aniline, a reaction useful for forming aldehydes. When mixed with 
 benzene containing thio-phene and sulphuric acid it is coloured deep 
 
388 ORGANIC CHEMISTRY 
 
 red, afterwards blue-violet ; all its derivatives, and also isatin, react 
 
 similarly. 
 
 ?j Being a ketonic acid, it unites with sodium bisulphite and with 
 
 CNH (see Phenyl-tartronic acid). Sodium amalgam converts it into 
 
 mandelic acid, and hydriodic acid into phenyl-acetic acid. H 2 S and 
 
 the alkali produce thio-phenyl-acetic acid (C. 1903, II. 1271). 
 
 Its methyl ester boils at 247. Its ethyl ester boils at 257. The 
 a-amide melts at 90. The j8-amide hydrate C 6 H 5 .CO.CONH 2 -fH 2 O 
 melts at 64. The y-amide melts at 134 (B. 12, 633 ; 20, 397). The 
 anilide, from y-benzil-monoxime (q.v.) and PC1 5 , melts at 63. 
 
 Benzoyl cyanide C 6 H 5 .CO.CN, melting at 32 and boiling at 207, is 
 obtained in the distillation of benzoyl chloride with mercuric cyanide, 
 and by the action of acetyl chloride (B. 20, 2196) upon iso-nitroso- 
 aceto-phenone. Sodium, in absolute alcohol, converts it into poly- 
 benzoyl cyanide (C S H 5 NO 2 )#, melting at 95 (/. pr. Ch. 2, 39, 260). 
 Alkalies change benzoyl cyanide to benzoic acid and potassium cyanide, 
 while concentrated hydrochloric acid converts it into benzoyl- 
 formic acid. 
 
 Concerning a trimolecular benzoyl cyanide (C 8 H 5 NO) 3 , yellow 
 needles, m.p. 194, obtained by transforming benzoyl bromide with 
 silver cyanide, see B. 40, 1655. 
 
 Chloro-iso-nitroso-aceto-phenone, benzoyl-formoximic acid chloride 
 C 6 H 5 .CO.C(: NOH)C1, melting at 131, is produced in the chlorination 
 of iso-nitroso-aceto-phenone (B. 26, R. 313). 
 
 Formazyl-phenyl-ketone C 6 H 5 COC(N : NC 6 H 5 ) : NNHC 6 H 5 , m.p. 
 142, from benzoyl-acetic acid or benzoyl-acetone with diazo-benzol, is 
 split by reduction into aniline and benzoyl-amidrazone C 6 H 5 CO(NH 2 ) : 
 NNHC 6 H 5 , m.p. 152 (/. pr. Ch. 2, 65, 139). 
 
 Benzoyl cyanide anile CeH 5 C(: NC 6 H 5 )CN, m.p. 72, from phenyl- 
 anilido-aceto-nitrile by oxidation with permanganate in acetone. 
 Similarly we obtain p-dimethyl-amido-benzoyl cyanide anile, m.p. 
 
 121 (B. 35, 3569)- 
 
 //NH\ 
 
 Phenyl-hydrazi-methylene-carboxylie acid c 6 H 5 .c( <^ | J.co 2 H. The 
 hydrazin salt melts at 119. Diphenyl-glyoxylic acid hydrazone 
 
 C 6 H 5 .C( : N)CO 2 H 
 
 I ' . Its diethyl ester melts at 138 (/. pr. Ch. 2, 44, 567). 
 C 6 H 5 .C( : N)C0 2 H 
 
 Phenyl-glyoxylie acid phenyl-hydrazone melts at 153 (A. 227, 341). 
 
 (jS-), Syn-phenyl-glyoxylie acid oxime melts at 147. (a-), Anti- 
 phenyl-glyoxylic acid oxime, iso-nitroso-phenyl-acetic acid C 6 H 5 .C 
 ( : NOH)CO 2 H melts at 128 (B. 24, 42) . The methyl ester melts at 138. 
 The dimethyl ester melts at 56 (B. 16, 519). Benzoyl cyanide oxime 
 C 6 H 5 .C(: NOH)CN, melting at 129 (B. 24, 3504), is obtained from 
 benzyl cyanide by means of amyl nitrite and sodium or nitrous acid 
 and sodium ethylate. Also from phenyl-glyoxime by boiling with 
 NaHO, or, direct, from co-dibromo-aceto-phenone with hydroxyl- 
 amine and alkali (B. 24, 3504 ; /. pr. Ch. 2, 66, 353). 
 
 Substituted Benzoyl- formic Acids. o- and p-Bromo-benzoyl-formie 
 acids melt at 93-io3 and 108 (B. 25, 3298, and 28, 259). 
 
 o-Nitro-benzoyl-formic acid NO 2 .C 6 H 4 CO.CO 2 H+H 2 O melts at 
 47, and, when anhydrous, at 122. The amide melts at 199. The 
 
PHENYL-PARAFFIN-KETONE-CARBOXYLIC ACIDS 389 
 
 nitrite melts at 54 (B. 23, 1577). The oxime, when acted upon with 
 water, yields CO 2 and o-nitro-benzo-nitrile. Salicylic acid is produced 
 when it is boiled with alkalies (B. 26, 1252). It forms two isomeric 
 phenyl-hydrazones (B. 23, 2080). 
 
 m-Nitro-benzoyl-formic acid melts at 77. The amide melts at 151. 
 The nitrite melts at 230 (145 mm.) (B. 14, 1186). 
 
 p-Nitro-benzoyl cyanide, m.p. 116, from iso-nitroso-p-nitro-benzyl 
 cyanide by splitting (/. pr. Ch. 2, 66, 353). 
 
 o-Amido-benzoyl-formie acid, isatinic acid, is produced on reduc- 
 ing o-nitro-benzoyl-formic acid with ferrous sulphate and sodium 
 hydrate, and in the action of alkalies on isatin. If it be separated 
 from its lead salt by means of hydrogen sulphide, and evaporated under 
 greatly reduced pressure at low temperature, it is obtained as a white 
 powder. Digestion of its solution converts it at once into its lactame 
 or lactime 
 
 Isatin, lactame of isatinic acid C 6 H 4 /^ ' , or lactime of isatinic 
 
 acid c e H 4 /^\C.OH (?), melting at 201. It was first obtained by 
 
 oxidising indigo. It consists of orange-red prisms. It dissolves in 
 the caustic alkalies with the formation of salts. The solution, violet 
 at first, soon becomes yellow, owing to the production of isatinates. 
 Isatin acts at the same time like a ketone. 
 
 Its other methods of formation and its derivatives will be discussed 
 later in connection with the hydro-indol derivatives. The isatin deri- 
 vatives referable to the lactame formula are designated pseudo- or 
 ^-derivatives, or n-derivatives i.e. those in which the recently entered 
 group is attached to nitrogen, whereas the true isatin derivatives are 
 referred to the lactime formula, because the latter appears to belong 
 to free isatin. 
 
 Aceto-isatinic acid CHg.CO.NHMCeH^CO.COaH, melting at 160, 
 results upon treating acetyl-^-isatin (see this) with alkalies, and then 
 with acids. Benzoyl-isatinie acid, melting at 188, is produced when 
 benzoyl-tetrahydro-quinolin is oxidised with KMnO 4 (B. 24, 772). 
 
 Acetyl-isatin C 6 H 4 /^^ ^ melts at 141. Benzoyl-isatin 
 
 melts at 206. 
 
 Anthroxanie acid C 6 H 4 J | > >0 , m .p. 190, is formed, with 
 
 other products, during the oxidation of isatinic acid with Caro's acid, 
 and by reduction of o-nitro-phenyl-glyoxalic acid with tin and glacial 
 acetic acid ; also by heating the o-nitroso-mandelic nitrile with con- 
 centrated HC1 (B. 39, 2344), an d by oxidation of anthroxane-aldehyde 
 with KMnO 4 (B. 16, 2222 ; /. pr. Ch. 2, 81, 254). 
 
 p-Dimethyl-amido-phenyl-glyoxylie ester (CH 3 ) 2 N.C 6 H 4 CO.CO 2 C 2 H 5 , 
 m.p. 187, is obtained from dimethyl-aniline ethyl-oxalic acid chloride, 
 or oxalic ester with A1C1 3 (B. 10, 2081 ; C. 1907, II. 310) ; the corre- 
 sponding chloride results from dimethyl-aniline and oxalyl chloride. 
 On heating, it decomposes into CO and p-dimethyl-amido-benzoyl 
 chloride (B. 42, 3486). p-Amino-phenyl-glyoxalic acid and its n-alky- 
 lated derivatives are also formed from the related amino-phenyl- 
 tartronic acids by oxidation (C. 1901, I. 237, 239). 
 
390 ORGANIC CHEMISTRY 
 
 o-Oxy-phenyl-glyoxylic acid HO[2]C 6 H 4 COCOOH, m.p. 57, from 
 isatinic acid through its diazo-sulphate ; the acid condenses with 
 phenylene-diamine to o-oxy-phenyl-oxy-quinoxalin, which may be 
 transformed into a lactone, the so-called cumaro-phenazin, and obtained 
 from that (B. 34, 2294) : 
 
 HO[2]C 6 H 4 C=N\ -- C 6 H 4 C=N 
 
 4 --- > 6 C= 
 
 o-Acetoxy-phenyl-glyoxylie acid, m.p. ioi-io6, with one molecule 
 H 2 O, is produced from its nitrile, m.p. 111, the result of the action of 
 silver cyanide upon acetyl-salicylic chloride (A. 368, 80). The lactone 
 corresponding to isatin 
 
 Cumarandione c^H^j^co, in yellow needles, m.p. 178, is ob- 
 
 tained by the oxidation of the so-called oxindigo with Cr0 3 in glacial 
 acetic acid (B. 42, 199). From it is derived iso-nitroso-cumaranone 
 
 : NOH, melting at 172 with decomposition (B. 35, 1640, 
 
 4346). The p-dimethyl-amido-anile of cumarandione C 6 H 4 ^ ^>C : NC 6 
 
 H 4 N(CH 3 ) 2) m.p. 185, is produced by the condensation of cumaranone 
 with p-nitroso-dimethyl-aniline (B. 44, 124). 
 
 Thio-isatin, thio-naphthene-quinone C 6 H 4 <^ g ^>CO, yellow prisms from 
 alcohol, m.p. 121, b.p. 247, from its anile, the transformation product 
 of dibromo-thio-indoxyl C 6 H 4 <^ /CBr 2 , and from iso-nitroso-thio- 
 
 \o _ / 
 
 indoxyl C 6 H 4 \ c ^>C : NOH, m.p. 172, and by splitting up with dilute 
 
 \o _ _/ 
 
 H 2 SO 4 . Dissolves in alkalies with formation of salts of thio-phenol- 
 o-glyoxylic acid, which, in the free state, easily fall back into the 
 anhydrides (B. 41, 227). 
 
 p-Methoxy-phenyl-glyoxylie acid melts at 89. 
 
 Veratroyl-carboxylie acid (CH 3 O) 2 [3, 4]C 6 H 3 .CO.C0 2 H, m.p. 138, 
 and piperonoyl-carboxylie acid (CH 2 O 2 )[3, 4]C 6 H 3 CO.CO 2 H, m.p. 148, 
 have been produced by the oxidation of anethol, of iso-eugenol-methyl 
 ether, and of iso-safrol (B. 24, 3488). The nitriles of the first two 
 acids, m.p. 64 and 117, are prepared from anisic acid chloride and 
 veratroyl chloride and HCN respectively in the presence of pyridin 
 (B. 42, 188). 2, 5-dioxy-phenyl-glyoxylic acid, m.p. 141, results from 
 oxidation of o-oxy-phenyl-glyoxylic acid with K persulphate in 
 alkaline solution (C. 1907, II. 901). 
 
 Homologous Phenyl-glyoxylic Acids. m-Tolyl-glyoxylie acid yields 
 
 so-called methyl-isatin CH 3 [5]C 6 H 3 { [ ' ] ^^ , m.p. 184. This is 
 
 obtained by boiling p-methyl-isatin-p-tolyl-imide, m.p. 259, the pro- 
 duct of the action of dichloro-acetic acid upon p-toluidin, with hydro- 
 chloric acid (B. 16, 2262 ; 18, 198). 
 
 p-Tolyl-glyoxylic acid . . . m.p. 96 (6.14,1750; 20,2049). 
 
 (p-)[2, 5]-Xylyl-glyoxylic acid . . . 75 (.1898,1.42). 
 
 (m-)[2, 4]-Xylyl-glyoxylic acid . 85 (/. pr. Ch. 2, 41, 485). 
 
 (o-)[2,3]-Xylyl-glyoxylicacid. . 92 (6.30,1766). 
 
 Mesityl-glyoxylic acid . . ii2 -ii6\ m 24 R . 
 
 [2, 4, 5]-Pseudo-cumyl-glyoxylic acid . 75 / 
 
PHENYL-PARAFFIN-KETONE-CARBOXYLIC ACIDS 391 
 
 2, 3, 4, 6- and 2, 3, 5, 6-Tetramethyl-phenyl-glyoxylic acid (B. 19, 
 
 233 ; 20, 3099). Cymyl-glyoxylic acid (C. 1898, I. 42). 
 
 Phenyi-pyro-raeemie acid C 6 H 5 .CH 2 .CO.CO 2 H melts at 154 with 
 evolution of carbon dioxide. It is formed when a-benzoyl-amido- 
 cinnamic acid (A. 275, 8) is boiled with caustic alkali or hydrochloric 
 acid, as well as by boiling phenyl-oxal-acetic ester with dilute sulphuric 
 acid (A. 271, 163). Ammonia converts it into a-phenacetyl-amido- 
 hydro-cinnamic acid, or phenacetyl-phenyl-alanin. Oxidised with 
 H 2 O 2 , in alkaline solution, it decomposes cleanly into CO 2 and phenyl- 
 acetic acid (C. 1904, I. 194). With benzaldehyde and concentrated 
 HC1 it unites to form /?, y-diphenyl-a-keto-butyrol-acetone (A. 333, 
 160). 
 
 o-Oxy-phenyl-pyro-raeemie acid HO.C 6 H 4 CH 2 .CO.CO 2 H is pro- 
 duced, like phenyl-pyro-racemic acid, from a-benzoyl-amido-o-oxy- 
 cinnamic acid and sodium hydroxide. Its lactone, a-oxo-hydro- 
 
 ( [i]CH 2 . CO 
 eumarin C 6 nJ I (?), m.p. 152, is produced when it is boiled 
 
 v C 2 ]O - CO 
 with acids (B. 18, 1187). 
 
 Nitro-substituted phenyl-pyro-racemic acids are obtained syntheti- 
 cally by condensation of oxalic ester, and o- or p-nitro-toluols with 
 sodium ethylate : 
 
 o-Nitro-phenyl-pyrc-raeemic acid NO 2 [2]C 6 H 4 CH 2 COCOOH, m.p. 
 121, gives, on reduction, n-oxy-indol and, further, a-indol-carboxylic 
 
 acid CJEi^CCOOH. p-Nitro-phenyl-pyro-racemic acid, m.p. 194 ; 
 
 o, p- and o, m-methyl-nitro-phetiyl-pyro-raeemie acid, m.p. 145 and 
 193 (B. 30, 1030 ; 31, 387). 
 
 Benzyl-pyro-racemic acid C 6 H 5 CH 2 CH 2 COCOOH+iJH 2 O, m.p. 
 47, results from the transposition of a-oxy-phenyl-crotonic acid by 
 means of NaHO, while HC1 forms the isomeric benzoyl-propionic acid ; 
 further, benzyl-pyro-racemic acid is also obtained by splitting up 
 benzoyl-oxal-acetic ester (A. 299, 28 ; B. 31, 3134). 
 
 B. Phenyl-paraffin-jS-ketone-carboxylie Acids are produced (i) by 
 a condensation, similar to the aceto-acetic ester formation, from ben- 
 zoic and fatty acid esters, aceto-phenone, and carbonic acid esters, 
 with alcohol elimination, in the presence of sodium alcoholate (see 
 Benzoyl-acetic ester) ; (2) by the introduction of alphyl residues, by 
 means of chlorides e.g. benzyl chloride, into aceto-acetic ester 
 (see Benzyl-aceto-acetic ester) ; (3) by action of benzaldehydes upon 
 diazo-acetic ester (see Benzoyl-acetic ester). ; (4) from malonic ester 
 acid chlorides and benzene, in presence of A1C1 3 (C. 1905, II. 30) ; (5) by 
 transposition of benzoyl chloride or bromide with Mg-a-halogen ali- 
 phatic acid esters (A. 347, 71) ; (6) by hydration of phenyl-propiolic 
 acid ester. 
 
 With hydroxylamine they yield oxime anhydrides, lactoximes, or 
 iso-azolones ; and with hydrazin and phenyl-hydrazin, hydrazin an- 
 hydrides, lactazames, or pyrazolones. ^ 
 
 Benzoyl-acetic acid C 6 H 5 .CO.CH 2 .CO 2 H, m.p. 103 with decom- 
 position into CO 2 and aceto-phenone. It breaks down, in the same 
 manner, when it is boiled with dilute acids. It is obtained by saponi- 
 fying its ethyl ester with caustic potash at the ordinary temperature. 
 Ferric chloride imparts a violet-red coloration to its solution. 
 
392 ORGANIC CHEMISTRY 
 
 Benzoyl-acetic ester C 6 H 5 .CO.CH 2 .CO 2 C 2 H 5 boils at 148 (n mm.). 
 (i) It was first prepared by dissolving phenyl-propionic ester in sul- 
 phuric acid and then diluting with water (B. 17, 66). (2) By the action 
 of sulphuric acid and water upon a-bromo-cinnamic ester (B. 19, 1392). 
 
 (3) It is most conveniently made by the action of dry sodium ethylate 
 or sodium upon ethyl benzoate and acetic ester (B. 20, 653, 2179). 
 
 (4) By splitting up benzoyl-acetic ester with ammonia (A. 291, 70). 
 
 (5) Small quantities of the ester are produced when esters of carbonic 
 acid act upon aceto-phenone together with sodium ethylate. (6) It 
 is also formed when benzaldehyde is heated with diazo-acetic ester. 
 (7) From malonic ester acid chloride, benzene, and A1C1 3 . (8) From 
 benzyl bromide and magnesium-bromacetic ester : 
 
 C 6 H 4 .C=C.C0 2 C 2 H 5 
 
 2. C 6 H 5 .CH=CBr.CO 2 C 2 H 5 
 
 3. C 6 H 5 .C0 2 C a H 5 +CH 3 C0 2 C 2 H 5 - 
 
 4. C 6 H 5 COCH(COCH 3 )CO 2 C 2 H 5 NH - H2 
 
 5. C 6 H 5 .CO.CH 3 +C 2 H 5 O.C0 2 C 2 H 5 
 
 6. C 6 H 5 .CHO+N 2 .CH.C0 2 C 2 H 5 - 
 
 7. C 6 H 6 +C1CO.CH 2 .C0 2 C 2 H 5 - - _ HQ 
 
 8. C 6 H 6 COBr+BrCH 2 C0 2 C 2 H 5 *- 
 
 C 6 H 5 .CO.CH 2 C0 2 C 2 H 5 
 Benzoyl-acetic ester. 
 
 Benzoyl-acetic ester volatilises with steam without decomposition 
 (A. 282, 155). Its odour resembles that of aceto-acetic ester. 
 
 It forms (i) with ammonia an addition product like that of aldehyde- 
 ammonia ; with amines it splits off water and yields imides e.g. j8- 
 methyl-imido-hydro-einnamic ester C 6 H 5 C(NCH 3 )CH 2 .CO 2 .C 2 H 5 (B. 29, 
 105) ; (2) with hydrazin it yields 3-phenyl-pyrazolone ; (3) with phenyl- 
 hydrazin, diphenyl-pyrazolone ; (4) with hydroxylamine, phenyl-is- 
 oxazolone; (5) with urea, phenyl-uracile ; (6) with guanidin, imido- 
 phenyl-uracile ; (7) with nitrous acid, the oxime ; (8) with diazo-ben- 
 zene chloride, the phenyl-hydrazone of benzoyl-glyoxylic ester ; (9) 
 with PC1 5 , j8-chloro-cinnamic chloride. Iodine converts its sodium 
 compound into dibenzyl-succinic ester, while with the alkylogens 
 horriologous benzoyl-acetic esters result. The hydrogen atoms of the 
 CH 2 group are also replaceable, step by step, by acid radicles. It 
 yields j8-ethoxy-cinnamic esters when acted upon with orthoformic 
 esters. The amide melts at 112 (A. 266, 332), and the anilide at 107 
 (A. 245, 374). 
 
 The dimethyl-acetal C 6 H 5 C(OCH 3 ) 2 CH 2 CO 2 CH 3 , b.p. 16 147, is 
 formed from phenyl-propiolic acid methyl ester with alcoholic Na 
 methylate solution at 125 (C. 1903, II. 664) ; diethyl-acetal, b.p. 13 
 
 153 (C. 1904, I. 659). 
 
 Benzoyl-aceto-nitrile, R-cyanaceto-phenone C 6 H 5 .CO.CH 2 .CN, melt- 
 ing at 80, is produced on boiling benzoyl-cyanacetic ester with water, 
 on acting upon sodium oxy-methylene-aceto-phenone with hydroxyl- 
 amine hydrochloride and sodium hydroxide (B. 24, 133), and upon 
 treating imido-benzoyl-aceto-nitrile or imido-benzoyl-methyl cyanide 
 with hydrochloric acid. 
 
 Imido-benzoyl-cyano-methane C 6 H 5 .C(: NH)CH 2 CN, melting at 
 86, results when sodium acts upon a dry ethereal solution of benzo- 
 
PHENYL-PARAFFIN-KETONE-CARBOXYLIC ACIDS 393 
 
 nitrile and methyl cyanide or aceto-nitrile (B. 22, R. 327). When 
 treated with hydroxylamine hydrochloride, the imido-group is replaced 
 by the oximido-group, and the latter adds itself to cyanogen with the 
 
 production of phenyl-isoxazolonimide II | melting at 
 
 C 6 H 5 C.CH 2 .C : NH 
 in (B. 26, R. 272). 
 
 p-Nitro-benzoyl-acetie acid C 6 H 4 (NO 2 ).CO.CH 2 .CO 2 H melts at 135, 
 and is produced by heating p-nitro-phenyl-propiolic ester with sulphuric 
 acid. It breaks down, on melting, into CO 2 and p-nitro-aceto-phenone. 
 o-Nitro-phenyl-propiolic ester is readily transposed into the isomeric 
 isatogenic ester (B. 17, 326). 
 
 o-, m-, and p-Nitro-benzoyl-acetic esters (liquid, m.p. 79 and 75 
 respectively) are best prepared by splitting up the corresponding nitro- 
 benzoyl-aceto-acetic esters (B. 35, 931, 933 ; C. 1904, I. 724). 
 
 Methyl-benzoyl-aeetic ester, boiling at 226 (225 mm.), when treated 
 with nitrous acid forms a-iso-nitroso-propio-phenone (B. 21, 2119). 
 a-Ethyl- and diethyl-benzoyl-acetie ester boil at 210 (90 mm.) and 223 
 (150 mm.). 
 
 Allyl-benzoyl-acetie ester boils at 220 (100 mm.). Benzoyl-tri- 
 methylene-carboxylie acid, melting at 148, decomposes at higher tem- 
 peratures into CO 2 and benzoyl-trimethylene (pp. 268 seq.) (B. 16, 2128, 
 2136). 
 
 a-Pheny!-aeeto-aeetie ester C 6 H 5 CH(COCH 3 )COOC 2 H 5 , b.p. u 146, 
 is obtained by saponifying its nitrile, m.p. 90, a condensation product 
 of benzyl cyanide and acetic ester, by means of sodium ethyiate (B. 31, 
 3160) ; similarly, we obtain propionyl-phenyl-aeetie ester C 6 H 5 CH 
 (COCH 2 CH 3 )CO 2 C 2 H 5 , b.p. 18 155, and propionyl-benzyl cyanide, m.p. 
 70 (B. 36, 2242). 
 
 2, 5-Dinitro-phenyl- and 2, 4, 6-trinitro-phenyl-aeeto-aeetic ester, 
 melting at 94 and 98, result from the action of 2, 5-dinitro-bromo- 
 benzene and 2, 4, 6-trinitro-chloro-benzene upon sodium aceto-acetic 
 ester (A. 220, 131 ; B. 22, 990 ; 23, 2720). 
 
 /CC\ C TT 
 
 Benzyl-aeeto-aeetic ester C 6 H 5 .CH 2 .CH< ^^ is derived from 
 
 \(^(j 2 f^ti 3 
 
 sodium aceto-acetic ester and benzyl chloride (A. 204, 179). It boils 
 at 276, and by the ketone decomposition yields benzyl-acetone (B. 15, 
 1875) ; by the acid decomposition it forms phenyl-propionic acid. 
 
 C. y- and 8-Ketone-earboxylic Acids C 6 H 5 .CO.CH 2 .CH 2 .CO 2 H, m.p. 
 1 1 6, are obtained (i) by the condensation of benzene and succinic an- 
 hydride by means of A1C1 3 (B. 20, 1376) ; (2) by condensation of benz- 
 aldehyde with maleic acid, or fumaric acid, by means of piperidin at 
 I50-i6o (C. 1903, I. 769) ; (3) by reducing j8-benzoyl-acrylic acid ; 
 (4) by the elimination of carbon dioxide from benzoyl-iso-succinic acid, 
 and (5) from phenacyl-benzoyl-acetic ester by the acid decomposition ; 
 (6) by boiling the HCN addition product of cinnamic aldehyde with 
 dilute hydrochloric acid, and carefully saponifying the phenyl-oxy- 
 crotonic acid produced at first when cold, which with heat rearranges 
 itself (B. 29, 2582 ; A. 299, 23) : 
 
 C.H 5 CH :CH.CH(OH)CN > C 6 H 5 CH : CH.CH(OH)COOH > C,H S CO.CH,.CH 1 COOH. 
 
 (7) Benzoyl-propionic acid is also formed by transposition of y- 
 phenyl-a-oxy-butyro-lactone (B. 36, 2529). 
 
394 ORGANIC CHEMISTRY 
 
 By splitting off H 2 O it yields phenyl-A 2 -eroto-laetone C 6 H 5 
 
 C : CH.CH 2 COO, m.p. 91. From the dibromide of cinnamic aldehyde 
 cyano-hydrin the isomeric oily phenyl-A 1 -croto-lactone is obtained, 
 
 C 6 H 5 .CH.CH : CH.COO, which easily transposes into the A 2 -lactone 
 (A. 319, 196). 
 
 Reduction transforms /?-benzoyl-propionic acid into y-phenyl- 
 butyro-lactone. 
 
 Phosphorus pentasulphide converts the acid into phenyl-oxy-thio- 
 phene (B. 19, 553). It yields two isomeric oximes, melting at 129 and 
 92 (B. 25, 1932). 
 
 a- Methyl - - benzoyl - propionic acid C 6 H 5 COCH 2 CH(CH 3 )COOH, 
 m.p. 136, by condensation of benzene and pyro-tartaric anhydride 
 with A1C1 3 (C. 1900, II. 172). 
 
 y-Benzoyl-butyrie acid C 6 H 5 COCH 2 CH 2 CH 2 COOH, m.p. 126, from 
 glutaric acid chloride with benzene and A1C1 3 , as well as a-benzoyl- 
 glutaric ester by ketone-fission (B. 31, 2001). 
 
 a-Phenyl-laevulinic acid C 6 H 5 .CH ^' m.p. 126, is 
 
 \Urj.2 . UL/ . L/ rig 
 
 derived from phenyl-aceto-succinic ester (B. 17, 72 ; 18, 790). /?- 
 Benzyl-laBVUlinic acid C^.CIi^CH^^ 2 ^ 11 ' from fi-benzal-lsevulinic 
 
 \ v> V-J . O-H.O 
 
 acid (A. 254, 202), m.p. 98. See Benzal-angelica-lactone. j8-Phenyl- 
 
 PTT C'O T-T 
 
 ^S*'I^>tT ' m.p. 83. It is obtained 
 
 from phenyl-dihydro-resorcin by the action of alkalies or acids (B. 26, 
 2057 ' A. 294, 322). Phenyl-dihydro-resorcin is again formed when 
 its esters are condensed with sodium alcoholate. 
 
 (9) PHENYL-ALCOHOL-KETONE-CARBOXYLIC ACIDS. 
 
 Benzoyl-glycollic acid C 6 H 5 .CO.CH(OH)CO 2 H, m.p. 125 (B. 16, 
 2133)- 
 
 a-Acidyl-phenyl-glycollic esters like p-toly-acetyl-glycol-methyl 
 ester CH 3 C 6 H 4 C(OH)(COCH 3 ).CO 2 CH 3 , b.p. 15 190, and p-dimethyl- 
 amido-phenyl-ace o tyl-glycollic-methyl ester (CH 3 ) 2 NC 6 H 4 C(OH) (COCH 3 ) 
 CO 2 CH 3 , m.p. 81, etc., are formed by condensation of aromatic hydro- 
 carbons and anilines with a, j8-diketo-butyric ester (C. 1909, I. 1795). 
 They are easily reduced to the corresponding aldehydes. 
 
 Acetoxy-phenyl-pyro-raeemic nitrile C 6 H 5 CH(O.COCH 3 ).CO.CN, 
 m.p. 52-5, b.p. 10 150, by heating acetyl-mandelic chloride with silver 
 cyanide (A. 368, 77). Derived from phenyl-oxy-pyro-racemic acid is 
 
 /OH 
 the acid C 6 H 6 CH(NHC 6 H 5 )C^ - COOH , m .p. 194, whose nitrile is 
 
 \N : CHC 6 H 5 
 
 obtained by condensation of phenyl-anilido-acetic nitrile with benz- 
 aldehyde and KCN (B. 29, 1732 ; 31, 2701). 
 
 y-Phenyl-y-keto-a-oxy-butyric acid C 6 H 5 .CO.CH 2 .CH(OH)CO 2 H, 
 m.p. 125, is obtained from its trichloride, chloral-aceto-phenone C 6 H 5 . 
 CO.CH 2 .CH(OH)CC1 3 , m.p. 76 (B. 26, 557). 
 
 From the geometrically isomeric phenyl-keto-oxy-butyric acids 
 are derived the bromination products of phenyl-aceto-acetic ester, and 
 a-propionyl-phenyl-acetic ester : a-bromo-phenyl-aeetie ester CH 3 CO 
 
DIKETONE-CARBOXYLIC ACIDS 395 
 
 CBr(C 6 H 5 )CO 2 C 2 H 5 and a-propionyl-phenyl-bromo-aeetie ester CH 3 CH 2 
 COCBr(C 6 H 5 )CO 2 C 2 H 5 ; also y-bromo-phenyl-aeetie ester CH 2 BrCOCH 
 (C 6 H 5 )CO 3 C 2 H 5 and y-bromo-propionyl-phenyl-acetie ester CH 3 CHBr 
 COCH(C 6 H 5 )CO 2 C 2 H 5 . The first two, distilled with steam, disintegrate 
 into CO, HBr, and atropic acid ester or j3-methyl-atropic acid ester ; the 
 last two, on heating with water, yield lactones, viz., a-phenyl-tetronie 
 
 acid CH 2 .C(OH) : C(C 6 H 5 )COO, m.p. 254, and a-Phenyl-y-methyl- 
 tetronic aeid CH 3 CH.C(OH) : C(C 6 H 5 )COO, m.p. 178 (B. 39, 3929). 
 
 y-Phenyl-tetronic acid C 6 H 5 CH.C(OH) : CH.C()6, m.p. 128, is formed 
 from the transformation product of acetyl-mandelic chloride with 
 sodium-malonic ester, by saponification and elimination of CO 2 (A. 
 368, 65). 
 
 (10) DIKETONE-CARBOXYLIC ACIDS. 
 
 Benzoyl-glyoxylie acid C 6 H 5 .CO.CO.CO 2 H. The ethyl ester, an 
 orange-coloured oil, boiling at I50-I53 (13 mm.), is formed by con- 
 ducting N 2 O 3 into a mixture of benzoyl-acetic ester and acetic an- 
 hydride. With water and alcohols it forms colourless hydrates and 
 alcoholates (C. 1907, II. 233). 
 
 The a-oxime and a-phenyl-hydrazone, of the ethyl ester of this 
 acid, have been prepared by the action of nitrous acid and diazo-benzol 
 chloride (B. 21, 2120) upon benzoyl-acetic ester. 
 
 Benzoyl-iso-nitroso-aeetic ester C 6 H 5 .CO.C(: NOH)CO 2 C 2 H 5 , m.p. 
 121. Benzoyl - a - phenyl - hydrazone - glyoxylic ester C 6 H 5 .CO.C 
 (: NNHC 6 H 5 )CO 2 C 2 H 5 , m.p. 65. The benzoyl-amido-acetic ester 
 obtained by reduction of benzoyl-iso-nitro-acetic ester yields on diazo- 
 
 tising benzoyl-acetic ester diazo-anhydride c ^c N/ N ' B ' 36 ' 3612 )' 
 Quinisatinic acid, o-amido-benzoyl-glyoxylic aeid NH 2 [2]C 6 H4CO. 
 
 CO.CO 2 H at 120 breaks down into water and its lactame or lactime. 
 
 It is obtained by oxidising )3, y-dioxy-carbo-styrile with ferric chloride. 
 
 Its lactame or lactime is 
 
 f[i]CO.CO f[i]CO.CO 
 
 Quinisatin C 6 HJ I or C 8 HJ I , m.p. 255-26o (B. 
 
 1[2]NH.CO U 2 ]N=(I:OH 
 
 17, 985)- 
 
 Benzoyl-pyro-racemic acid C 6 H 5 .CO.CH 2 .CO.CO 2 H, m.p. 157, is 
 prepared from its ethyl ester (melting at 43), produced in the condensa- 
 tion of aceto-phenone and oxalic acid (B. 21, 1131). Ferric chloride 
 imparts a blood-red colour to the alcoholic solution of the ester. Ben- 
 zoyl-pyro-racemic chloralide, see B. 31, 1306. Nucleus-substituted 
 benzoyl-pyro-racemic esters, see B. 34, 2477 ; 36, 2695. 
 
 \Yhen benzoyl chloride acts upon aceto-acetic ester, it produces 
 benzoyl-aceto-acetic ester C 6 H 5 .CO.CH.(CO.CH 3 ).CO 2 C 2 H 5 . This de- 
 composes into aceto-phenone and benzoyl-acetone (B. 18, 2131). 
 
 o-, m-, and p-Nitro-benzoyl-aceto-acetie ester (A. 221, 323 ; B. 35, 
 
 /COH 
 Aceto - phenone - aceto - acetic ester C 6 H 6 .CO.CH 2 .CH.<^ CO 2 CH melts 
 
 at I30-i40, with decomposition into CO 2 and aceto-phenone- 
 acetone. Its ethyl ester is produced by the action of co-bromo-aceto- 
 
396 ORGANIC CHEMISTRY 
 
 phenone upon sodium aceto-acetic ester (B. 16, 2866). Like aceto- 
 phenone - acetone, the ester readily forms a furfurane derivative. 
 On treatment with alcoholic potash it passes into y-phenyl-a-acetyl- 
 crotonic lactone. 
 
 0-Phenaeyl-laevulinic acid, see B. 34, 1263. 
 
 (n) PHENYL-PARAFFIN-DICARBOXYLIC ACIDS. 
 
 The phenyl-paramn-dicarboxylic acids, like the aliphatic, saturated 
 dicarboxylic acids, can be arranged into malonic acids, ethylene-succinic 
 acids, etc. 
 
 Phenyl-malonic Acids. Phenyl-malonie acid C 6 H 5 .CH(CO 2 H) 2 
 melts at 152, splitting off CO 2 and forming phenyl-acetic acid. Its ester, 
 boiling at 171 (14 mm.), is formed from phenyl-oxalacetic ester by the 
 elimination of carbon monoxide (B. 27, 1091). Dinitro-phenyl-malonic 
 ester (NO 2 ) 2 .C 6 H 3 .CH(CO 2 C 2 H 5 ) 2 , melting at 51, is obtained by the 
 action of bromo-dinitro-benzene upon sodium malonic ester (B. 21, 2472 ; 
 22, 1232 ; 23, R. 460 ; 26, R. 10). 
 
 2, 4, 6-Trinitro-phenyl-malonic ester, picryl-malonic ester (NO 2 ) 3 
 C 6 H 2 CH(CO 2 C 2 H 5 ) 2 , exists in two modifications, melting at 58 and 
 64 (B. 28, 3066; 29, R. 997; C. 1899, H- 2 5)- Bromo-thymo- 
 quinone-malonie ester [C 6 O 2 Br(C 3 H 7 )]CH(CO 2 C 2 H 5 ) 2 , m.p. 78, gives 
 blue salts with metals (B. 34, 1558). 
 
 Phenyl-eyano-acetie acid C 6 H 5 CH(CN).COOH, m.p. 92. Its ethyl 
 ester, b.p. 275, is formed by the action of Na and carbonic acid ester 
 upon benzyl cyanide. The amide, m.p. 147, gives, on treatment with 
 PC1 5 , phenyl-malonic nitrile C 6 H 5 CH(CN) 2 , m.p. 69, b.p. 21 153 
 (C. 1904, II. 953). 
 
 Benzyl - malonic acid, ft - phenyl - iso - succinic acid C 6 H 5 .CH 2 .CH 
 (CO 2 H) 2 , melting at 117, is obtained from its ester, produced in the 
 action of benzyl chloride upon sodium-malonic ester, as well as by the 
 reduction of benzal-malonic acid (A. 218, 139). 
 
 o- and p-Nitro-benzyl-malonic ester (B. 20, 434). The o-acid is 
 condensed by sodium hydroxide to n-oxy-a-indol-carboxylic acid 
 (B. 29, 639). Methyl-benzyl-malonie acid (A. 204, 177). j8-Phenyl- 
 ethyl-malonic-aeid ester C 6 H 5 (CH 3 )CH.CH(COOC 2 H 5 ) 2 , b.p. 15 230, by 
 attachment of CH 3 MgI to benzal-malonic ester. The acid melts at 
 144 with decomposition into CO 2 and /3-phenyl-butyric acid (C. 1905, 
 II. 1023). 
 
 C 6 H 5 .CH.CO 2 H 
 
 Phenyl-succinic Acids. Phenyl-succinie acid , melt- 
 
 CH 2 .C0 2 H 
 
 ing at 167, results from a>-chloro-styrol C 6 H 5 .CH : CHC1, as well as from 
 benzal-malonic ester, by means of potassium cyanide (A. 293, 338) ; by 
 the decomposition of phenyl-aceto-succinic ester, by means of very con- 
 centrated caustic potash ; from phenyl-ethane-tricarboxylic acid, and 
 from the so-called hydro-cornicularic acid Ci 7 H 16 O 8 . Its anhydride 
 melts at 54 (B. 23, R. 573), and another modification at 150 (M. 24, 
 413 ; C. 1907, 1. 720). Chloride, b.p. 12 151. Dimethyl ester, m.p. 58, 
 b.p. 12 161. 
 
 Ester Acids. By semi-esterification of phenyl-succinic acid, or 
 attachment of methyl alcohol to the anhydride, we get about 75 per 
 cent, phenyl-succinic ^-methyl-ester a-acid C 6 H 5 CH(CO 2 H).CH 2 CO 2 
 
PHENYL-PARAFFIN-DICARBOXYLIC ACIDS 397 
 
 CH 3 , m.p. 92, and about 25 per cent, phenyl-succinie a-methyl-ester 
 C 6 H 5 CH(CO 2 CH 3 ).CH 2 CO ? H, m.p. 103. 
 
 Pure a-methyl ester /?-acid is obtained by semi-saponification of 
 the neutral ester, and the j3-methyl ester a-acid from j8-phenyl-- 
 cyano-propionic methyl ester C 6 H 5 .CH(CN).CH 2 CO 2 CH 3 , m.p. 55, by 
 saponification of the cyanogen group. The constitution of the two 
 isomeric ester acids follows from the transformation of the ester acid 
 chlorides with benzene and ACC1 3 , whereby the j3-methyl ester a-acid 
 passes into desyl-acetic ester and the a-methyl j8-acid into phenyl- 
 phenacyl-acetic ester (A. 354, 117). 
 
 Phenyl-succinie -amido-a-acid C 6 H 5 CH(COOH).CH 2 CONH 2 , m.p. 
 145, formed by attachment of NH 3 to the anhydride, the isomeric 
 phenyl-a-amido-^-acid C 6 H 5 CH(CONH 2 ).CH 2 COOH, m.p. 159, from 
 -phenyl-/?-cyano-propionie acid (q.v.). 
 
 o-Oxy-phenyl-succinic acid melts with decomposition at 150. It 
 is obtained from cumarin and potassium cyanide (A. 293, 366). 
 
 C 6 H 5 .CH.CO 2 H 
 
 Phenyl-methyl-suceinie acids have been obtained in 
 
 CH 3 .CHCO 2 H 
 
 two modifications, melting at 170 and 192 (B. 24, 1876). 
 C 6 H 5 .CH 2 .CH.CO 2 H 
 
 Benzyl-succinic acid melts at 161, and results 
 
 CH 2 .C0 2 H 
 
 from sodium ethan-tricarboxylic ester, or sodium ethan-tetra-carboxylic 
 ester by the action of benzyl chloride, etc. (B. 17, 449), as well as by 
 the reduction of phenyl-itaconic acid (B. 23, R. 237). It forms an 
 anhydride, melting at 102. 
 
 Phenethyl-succinic acid C 6 H 5 CH 2 CH 2 CH(COOH)CH 2 COOH, m.p. 
 136, by reduction of styryl-succinic acid, and from hydro-cinnamyl- 
 idene-malonic acid, with KCN. 
 
 Phenyl-ghitaric Acid. a-Phenyl-glutarie acid C 6 H 5 CH(COOH)CH 2 
 CH 2 COOH, m.p. 83, from C 6 H 5 CH(COOR)CH 2 CH(COCH 3 )COOR or 
 C 6 H 5 C(COOR) 2 CH 2 CH 2 COOR by splitting; easily passes into the 
 anhydride, m.p. 95 (B. 34, 4175). 
 
 /3-Phenyl-glutaric acid C6H 5 CH(CH 2 COOH) 2 , m.p. 142, by splitting 
 up j8-phenyl-propane-aa 1 -tri- or tetracarboxylic ester, the condensation 
 products of cinnamic ester, or benzol-malonic ester, with malonic 
 ester by means of sodium ethylate. By nitration it is transformed 
 into a mixture of o-, m-, and p-nitro-phenyl-glutarie acids, m.p. 205, 
 204, and 240. The o-nitro-acid gives, on reduction with SnCl 2 
 
 and HC1, hydro-carbo-styrile-y-acetie acid c 6 H 4 / r [l n ] (CH2COOH) - a 
 
 UL2jrlrl U(_) ' 
 
 m.p. 183 (B. 40, 1586). Homologous and substituted jS-phenyl-glutaric 
 acids, see A. 360, 344. /3-Phenyl-a-methyl-glutarie acid, m.p. 125, from 
 the result of attaching methyl-malonic ester to benzal-malonic ester. 
 
 (12) PHENYL-ALCOHOL-DICARBOXYLIC ACIDS. 
 
 A general method for preparing these substances consists in the 
 condensation of aromatic hydrocarbons, anilines, and phenols, and 
 mesoxalic acid ester or alloxane (all in one), under the influence of 
 concentrated sulphuric acid (C. 1909, I. 1560). They are easily 
 oxidised to the corresponding phenyl-glyoxylic acids and aromatic 
 aldehydes (see C. 1910, I. 25). 
 
398 ORGANIC CHEMISTRY 
 
 Phenyl-tartronie methyl ester C 6 H 5 C(OH)(CO 2 CH 3 ) 2 , m.p. 67, b.p. }1 
 165 ; p-tolyl-tartronie methyl ester, m.p. 72 ; p-methoxy- and p-di- 
 methyl-amido-phenyl-tartronic methyl ester melt at 118 and 115. 
 
 Trinitro-phenyl-tartronie ester (NO 2 ) 3 C 6 H 2 C(OH)(CO 2 C 2 H 5 ) 2 , m.p. 
 117, by oxidation of trinitro-phenyl-malonic ester with HNO 3 (C. 
 1899, II. 25). 
 
 Benzyl-tartronie acid C 6 H 5 .CH 2 .C(OH)(CO 2 H) 2 melts at 143, with 
 decomposition into CO 2 and /3-phenyl-lactic acid. It results from the 
 action of caustic potash on benzyl-chloro-malonic ester, the product 
 obtained from the interaction of benzyl chloride and sodium chloro- 
 malonic ester (A. 209, 243). a Anilido-, phenyl-hydrazido-benzyl- 
 malonic ester, etc., are produced by the addition of the respective bases 
 to benzal-malonic ester (B. 28, 1451 ; 29, 813). 
 
 j8-Methoxy-benzyl-malonic acid C 6 H 5 .CH(OCH 3 ).CH(CO 2 H) 2 melts 
 at 115 with decomposition into methyl alcohol and benzal-malonic 
 acid, from whose ester the j3-methoxy-benzyl-malonic ester is pro- 
 duced by addition of sodium methylate (B. 27, 289). 
 
 C 6 H 5 .C(OH)C0 2 H 
 
 Phenyl-malic Acids. a-Phenyl-a-oxy-succinie acid 
 
 in 2 . co 2 H 
 
 m.p. 187, is produced by the action of bromine, phosphorus, and water 
 upon phenyl-succinic acid. 
 
 C 8 H 5 .CH.C0 2 H 
 
 a-Phenyl-S-oxy-suceinie acid , m.p. I5o-i6o, 
 
 CH(OH).C0 2 H 
 
 results from the interaction of phenyl-formyl-acetic ester, prussic acid, 
 and hydrochloric acid (B. 23, R. 573). 
 
 Benzyl-malic acid ^^^H^^CO,^ m ' p> I55 ' from the con " 
 densation product of chloral with benzyl-malonic acid by saponification 
 with KOH (B. 38, 2737). 
 
 Phenyl-itamalic acid may be obtained in the form of its lactone acid, 
 
 es..^-a 
 
 phenyl-paraconic acid I ")CH 2 , m.p. 109, by heating 
 
 benzaldehyde with sodium succinate and acetic anhydride (A. 256, 63). 
 For other methods, see B. 33, 1294 ; A. 321, 127 ; 330, 292. 
 
 Phenyl-paraconic acid, upon distillation, breaks down into carbon 
 dioxide, phenyl-butyro-lactone, and phenyl-iso-crotonic acid. A further 
 product is a-naphthol (q.v.). 
 
 Phenyl-itaconic acid is produced when metallic sodium, or sodium 
 ethylate, acts upon phenyl-paraconic esters. Hydriodic acid reduces 
 it to benzyl-succinic acid and phenyl-butyric acid (B. 29, 15). 
 
 o-, m-, and p-Chloro-phenyl-paraeonie acids result from the con- 
 densation of monochloro-benzaldehydes with sodium succinate, and 
 yield three chlorinated naphthols (B. 21, R. 733). 1, 3, 4-Diehloro- 
 phenyl-paraconic acid, m.p. 138, forms two dichloro-naphthols (B. 28, 
 R. 244). 
 
 a- and j8-Methyl-phenyl-paraeonic acids are produced in the con- 
 densation of benzaldehyde with pyro-tartaric acid, and yield methyl-a- 
 naphthols (A. 255, 257). 
 
 a-Phenyl-y-valero-lactone-earboxylie acid c 6H 5 .CH.co\ o ^ m p 
 
 C0 2 H.CH.CH^CH 3 
 167, is produced in the reduction of phenyl-aceto-succinic ester 
 
PHENYL-KETONE-DICARBOXYLIC ACIDS 399 
 
 (B. 18, 791). S-Phenyl-S-valero-lactone-y-earboxylic acid, m.p. 161, 
 by reduction of a-benzoyl-glutaric acid, on distillation, gives A 3 -dihydro- 
 cinnamenyl-acrylic acid. 
 
 (13) PHENYL-KETONE-DICARBOXYLIC ACIDS. 
 
 Benzoyl-malonic ester C 6 H 5 .CO.CH(CO 2 .C 2 H 5 ) 2 and o-nitro-benzoyl- 
 malonic ester are produced by the action of benzoyl chloride and o-nitro- 
 benzoyl chloride upon sodium-malonic ester (B. 20, R. 381). The 
 latter yields quinolin derivatives upon reduction (B. 22, 386). 
 
 Benzoyl-cyano-acetic methyl ester c 8 H 5 .co.CH<^^ 2 ' CH3 , m.p. 74, 
 
 is formed from cyano-acetic methyl ester and benzoyl chloride. Its 
 ethyl ester, m.p. 41, from benzoyl-acetic ester and cyanogen chloride, 
 yields cyano-aceto-phenone on boiling with water. 
 
 Phenyl-aeetyl-malonie ester C 6 H 5 CH 2 .CO.CH(COOC 2 H 5 ) 2 , from 
 phen-acetyl chloride and Na-malonic ester, is condensed by concentrated 
 H 2 SO 4 to naphtho-resorcin-carboxylic ester (A. 298, 374). 
 
 Benzoyl-iso-succinie ester C 6 H 5 .CO.CH 2 .CH(CO 2 C 2 H 5 ) 2 is obtained 
 from oj-bromaceto-phenone and sodium-malonic ester (B. 18, 3324). 
 
 a-Benzoyl-glutarie ester C 6 H 5 COCH(CO 2 C 2 H 5 )CH 2 CH 2 CO 2 C 2 H 5 , 
 b.p. 12 200-2io, from Na-benzoyl-acetic ester with /?-iodo-propionic 
 ester. 
 
 jS-Benzoyl-glutaric acid C6H 5 COCH(CH 2 COOH) 2 , m.p. 122, on 
 stronger heating, gradually splits off H 2 O and passes into the dilactone 
 
 m.p. 137. The latter is formed synthetically 
 
 _ 
 
 from benzoic anhydride and sodium tricarbalkylate at i35-i4o 
 with rejection of CO 2 and H 2 O ; it can easily be broken up into 
 j8-benzoyl-glutaric acid, and is reduced by sodium amalgam to phenyl- 
 
 butyro-lactone-acetic acid C 6 H 5 CH.CH(CH 2 COOH)CH 2 COO, m.p. 114 
 (A. 314, 58). 
 
 C 6 H 5 .CH.CO.C0 2 .C 2 H 5 
 
 Phenyl-oxalaeetic ester is formed from oxalic 
 
 C0 2 .C 2 H 5 
 
 ester, phenyl-acetic ester, and sodium (B. 20, 592). See Phenyl- 
 malonic acid. 
 
 C 6 H 5 .CH.CO.C0 2 C 2 H 6 
 Phenyl-eyano-pyro-raeemic ester is obtained 
 
 CN 
 
 from oxalic ester, benzyl cyanide, and sodium (A. 271, 172) . See Phenyl- 
 pyro-racemic acid. 
 
 C,H 5 .CH.C0 2 H 
 Phenyl-aceto-suecinie ester is formed from sodium 
 
 CH 3 .CO.CH.C0 2 H 
 
 aceto-acetic ester and phenyl-bromacetic ester (B. 17, 71). 
 
 C 6 H 5 .CH 2 .CH.C0 2 H 
 
 Benzyl-aceto-succinic ester results from the 
 
 CH 3 .CO.CH.C0 2 H 
 
 interaction of sodium aceto-succinic ester and benzyl chloride (B. 
 11, 1058). 
 
 Benzyl-oxalacetie ester 'oul' an U ' from oxalic ester ' 
 
 with hydro-cinnamic ester and Na alcoholate (B. 31, 554). 
 
400 ORGANIC CHEMISTRY 
 
 (14) PHENYL-OXY-KETONE-DICARBOXYLIC ACIDS. 
 
 C 6 H 6 .CH.CH CO 2 C 2 H 5 
 
 Keto-phenyl-paraeonic ester I ^ co (B. 26, 2144). 
 
 O CO/ 
 
 CO O 
 
 a-Benzoyl-8-ehloro-y-valero-laetone , m.p. 
 
 C 6 H 5 COCHCH 2 .CH.CH 2 C1 
 
 106, from Na-benzoyl-acetic ester with epichloro-hydrin, is split up 
 by alkali into benzoic acid and y, S-dioxy-valerianic acid, or into CO 2 
 and benzoyl-butane-diol C 6 H 5 .CO.CH 2 .CH 2 .CH(OH).CH 2 OH, m.p. 91 
 (C. 1901, II. 237). 
 
 (15) PHENYL-PARAFFIN-TRICARBOXYLIC ACIDS. 
 
 Phenyl-earboxyl-sueeinie acid, phenyl-ethane-triearboxylic acid. 
 
 Its ester is formed when phenyl-chloracetic ester acts upon sodium- 
 malonic ester (A. 219, 31). The acid breaks down, on heating, into CO 2 
 and phenyl-succinic acid (B. 23, R. 573). 
 
 a, j3-Dieyano--phenyl-propionie ethyl ester C 6 H 5 CH(CN).CH(CN). 
 CO 2 C 2 H 5 , m.p. 68, by condensation of mandelic acid nitrile with 
 sodium-cyano-acetic ester (C. 1906, II. 1563). 
 
 a-Phenyl-triearballylie acid C 6 H 5 CH(COOH).CH(COOH)CH 2 COOH, 
 m.p. 110, by saponification of the reaction products of KCN and 
 phenyl-itaconic acid ester (C. 1903, II. 496). 
 
 Phenyl-butane-triearboxylie acid CeH5 CH'(CO H?CH co tr trans - form 
 (+JH 2 O), m.p. 195; cis-form, m.p. 179, by saponification, and CO 2 , 
 elimination from the condensation product of cinnamic ester with 
 Na-cyano-acetic ester and bromo-acetic ester ; both acids yield the 
 same anhydride acid, m.p. 135 (C. 1899, II. 833). The same structure 
 is ascribed to the tricarboxylic acid obtained by attaching cinnamic 
 acid to succinic acid ester, m.p. 200 with decomposition, which, how- 
 ever, has quite different properties (A. 315, 219). 
 
 jS-Phenyl-pimelin- 1 -aearie acid ^'^^^L , m.p. 142, 
 
 Url 2 .Cl(L'rl2^U 2 rl)2 
 
 obtained from the condensation product of cinnamic aldehyde with 
 three molecules sodium-malonic ester, by saponification with con- 
 centrated HBr (A. 360, 337). 
 
 (16) PHENYL-KETO-TRICARBOXYLIC ACIDS. 
 
 a- and jS-Benzoyl-tricarballylie acids C 6 H 5 .CO.CH(COOH)CH(COOH) 
 CH 2 COOH and C 6 H 5 COC(COOH)(CH 2 COOH) 2 . Their esters are 
 formed from chloro-succinic ester and benzoyl-acetic ester, or from 
 benzoyl-acetic ester with bromo-acetic ester and sodium ethylate (B. 29, 
 R. 788). 
 
 (17) POLYKETO-POLYCARBOXYLIC ACIDS. 
 
 (17) By condensation of benzaldehydes, and substitution benz- 
 aldehydes with aceto-acetic esters, and similar substances, in the 
 presence of aliphatic amines, several polyketo-polycarboxylic acids 
 of the aromatic series have been obtained, which are interesting 
 partly by their isomeric forms, and partly on account of their capacity 
 for further condensations. It is, however, doubtful whether these 
 compounds still contain the open aliphatic chain, or whether they 
 
PHENYLENE-OXY-DICARBOXYLIC ACIDS 401 
 
 ought to be regarded as cyclic-ketone-alcohol-carboxylic acids of the 
 hydro-aromatic series (A. 323, 83 ; 332, 22). Benzylidene-bis-aceto- 
 acetic ester C 6 H 5 CH[CH(COCH 3 )CO 2 C 2 H 5 ] 2 (?) is obtained from benz- 
 aldehyde with two molecules aceto-acetic ester in three stereo-isomeric 
 keto-forms p, m.p. 150 ; 2 , m.p. 154 ; and j3 3 , m.p. 108, which, 
 through their sodium salts, can be converted into the keto-enol forms 
 a, m.p. 61 ; a 2 , liquid ; a 3 , m.p. 6$-6j . The benzylidene-bis-aceto- 
 acetic ester is easily condensed with elimination of H 2 O to a cyclo- 
 hexanone derivative (A. 313, 129). 
 
 Addendum. A number of compounds attach themselves to the 
 phenyl-poly-alcohols and their oxidation products. They may be 
 regarded as derived from the various classes of bodies which have just 
 been described, by assuming, in addition to the one aliphatic side 
 chain, a second or more groups (mostly carboxyl groups) attached to 
 the benzene ring. Most of the bodies belonging here are o-di-deriva- 
 tives of benzene, o-phenylene derivatives, obtained in part from 
 o-phthalic acid, and in part by the oxidation of derivatives of ortho- 
 condensed hydrocarbons e.g. indene and naphthalene. Mention may 
 be made of the subjoined compounds. Some of them are intimately 
 related to the dicarboxylic acids, which have been discussed, carrying 
 the one carboxyl group in the nucleus and the other in the side chain. 
 
 (18) PHENYLENE-OXY-DICARBOXYLIC ACIDS. 
 
 o-Carbo-mandelic acid CO 2 H[2]C 6 H4.CH(OH)CO 2 H decomposes 
 readily into water and a lactone-carboxylic acid : 
 
 Phthalide-carboxylic acid c H <{co>o zH ' meltin g at X 49> and 
 beyond 180 decomposing into carbon dioxide and phthalide. It is 
 formed by the reduction of o-carbo-phenyl-glyoxylic acid (B. 18, 381 ; 
 31, 373), or by boiling the eo-dibromo-aceto-phenone-o-carboxylic acid 
 HO 2 CC 6 H 4 COCHBr 2 , m.p. 132, with water (B. 40, 71), as well as by the 
 action of alkali upon tetrachloro-hydrindone (A. 334, 341). Substituted 
 phthalide-carboxylic acids, see A. 296, 344. 
 
 Acetonyl-phthalide c H *{co>o H2COCH3 > m -P- 68 ' from acetone 
 with phthal-aldehydic acid (C. 1898, II. 980). 
 
 Phthalide-acetic acid C 6 H 4 ^^^ 2 - C 2H , melting at 150, is derived 
 from phthalyl-acetic acid by reduction (B. 10, 1558, 2200). 
 
 Meconin-acetic acid (HO) 2 [ 5> 6]C 6 H 2 | [ *^~Q Ha - CO8H , melting at 
 228, results from the action of hydriodic acid upon meconin-acetic 
 acid (CH 3 0) 2 [ 5 ,6]C 6 H 2 ^^ ] ^ 2 - C 2H . The latter is formed in the 
 
 condensation of opianic acid with malonic acid, glacial acetic acid, 
 and sodium acetate (B. 19, 2295). 
 
 ( [i]CH 2 .CH.CO 2 H 
 
 Dihydro-iso-cumarin-carboxylie acid C 6 HJ ' , melting 
 
 ( [2]CO O 
 
 at 153, is isomeric with phthalide-acetic acid. It is produced in the 
 oxidation of dihydro-naphthol (see this) with potassium permanganate 
 (B. 26, 1841). 
 
 VOL. II. 2 D 
 
402 ORGANIC CHEMISTRY 
 
 Phthalide-propionic acid ^, melting at 140, 
 
 results from the reduction of phthalyl-propionic acid (B. 11, 1681). 
 
 ( [i]CH(C0 2 H)0 
 o-Phenylene-aeeto-glyeol-laetone acid C 6 HJ +iiH 2 o, 
 
 1 [2]CH 2 --- 60 
 m.p. 85, is obtained from phenylene - diacetic acid, bromine, 
 
 phosphorus, and water (B. 26, 223). 
 
 f[i]CH(OH).CH.C0 2 H 
 o - Carbo - phenyl - glyceric acid lactone C 6 H 4 -{ 
 
 l[2]CO - O 
 
 m.p. 202, is produced when jS-naphtho-quinone is oxidised with a 
 bleaching-lime solution. When the lactone acid is heated with hydro- 
 chloric acid it loses water and becomes o-carbon-a-oxy-cinnamic acid 
 lactone (B. 27, 198). 
 
 (19) PHENYLENE-KETONE-DICARBOXYLIC ACIDS. 
 o-Carbo-phenyl-glyoxylic acid, phthalonic acid 
 
 m.p. I38-I40, is formed in the oxidation of o-hydrindene-carboxylic 
 acid (q.v.), naphthalene, a-naphthol, jS-naphthol, and the oxy-quinone 
 of jS-phenyl-naphthalene with potassium permanganate (A. 240, 142 ; 
 
 B. 31, 369). It yields o-carbo-mandelic acid upon reduction, and also 
 homo-phthalic acid. Heating the acid alone gives phthalic anhydride, 
 phthal-aldehydic acid, and biphthalyl. Ester and ester acids, see 
 
 C. 1904, I. 514. 
 
 Trichloro-aceto-benzoic acid c 6 H 4 /W^>.cci 3 ^ ^ 0> and 
 
 UL2JCO 2 H 
 
 tribromo-aeeto-benzoie acid, m.p. 160, result when chlorine or bromine, 
 in glacial acetic acid, acts upon phthalyl-acetic acid (B. 10, 1556). 
 
 o-Carbo-benzoyl-aeetic acid CA/?^^ **, m.p. 90 with 
 
 U [2 ]CO 2 H 
 
 decomposition into carbon dioxide and aceto-phenone-o-carboxylic 
 acid, is formed when phthalyl-acetic acid is dissolved in an excess 
 of caustic soda and precipitated with acids (B. 10, 1553). 
 
 co-Cyano-aceto-phenone-o-earboxylie acid melts at 136 (B. 26, 
 
 Benzoyl-eyano-aeeto-ester-o-earboxylic acid 
 
 C0 2 H[2]C 6 H 4 .CO.CH/CA H 5) m.p. I2i, is produced by the action of 
 
 \CN 
 soda upon phthalyl-cyano- acetic ester (B. 26, R. 370). 
 
 o- Carbo - benzoyl - propionic acid CJBi-*, m.p. 
 
 I, [2JCO 2 H 
 
 137. The double lactone C 9 H 4 /^ H 2- CH 2- CO , corresponding to this 
 
 acid, is produced on heating succinic anhydride and phthalic anhydride 
 with sodium acetate (B. 11, 1680 ; 18, 3119). 
 
 (20) TRI- AND TETRACARBOXYLIC ACIDS. 
 
 Benzyl - malonic - o - earboxylie acid, o-carbo- benzyl -malonic acid 
 )^ breaks down at I9Q o into hydro-cinnamic-o- 
 
OXY-TRI-, TETRA-, AND PENTACARBOXYLIC ACIDS 403 
 
 carboxylic acid and CO 2 . Its diethyl ester results from the reduc- 
 tion of phthalyl-malonic ester (A. 242, 37). 
 
 o-, m-, and p-Xylylene-dimalonic tetra-ethyl esters C 6 H 4 [CH 2 .CH 
 (CO 2 C 2 H 5 ) 2 ] 2 are produced in the reduction of the three corresponding 
 xylylene-diehloro-dimalonie esters CeH^CHaCCltCOgC^sJJ^ which 
 are the products of the action of sodium chloro-malonic ester upon the 
 co-xylylene dibromides (B. 21, 31). The xylylene-dimalonic acids 
 break down, on heating, into phenylene-dipropionic acids and 2CO 2 . 
 
 m-Xylylene-diaceto-acetic ester C 6 H 4 [i, 3][CH 2 .CH(COCH 3 )CO 2 R] 2 
 from m-xylylene bromide and Na-aceto-acetic ester (B. 34, 2790). 
 
 (21) OXY-TRI-, TETRA-, AND PENTACARBOXYLIC ACIDS. 
 
 (C[CH 2 .CO 2 H] 2 
 
 Phthalyl-diacetic acid c^nJ , m.p. 158, is obtained 
 
 (coo 
 
 from phthalyl-dimalonic acid C 6 H 4 {^ '* H )^ (A 242> go) 
 
 (coo 
 Phthalide-triearboxylicacid (COOH) 2 C 6 H 2 / CH ^ OOH , by condensa- 
 
 tion of pyro-racemic acid and diacetyl-glyoxylic acid (CH 3 COO) 2 CH. 
 COOH with alkalies. On boiling with water the acid loses CO 2 , and 
 
 passes into phthalide-dicarboxylic acid (CO 2 H) 2 C 6 H 2 / 2 \o, which, on 
 
 \O(J r 
 
 oxidation, yields prehnitic acid (A. 311, 132). 
 
 (22) KETONE-TRICARBOXYLIC ACIDS. 
 
 2, 6 - Diearbo - phenyl - glyoxylie acid (CO 2 H) 2 [2, 6]C 6 H 3 CO.CO 2 H, 
 melting at 238, is formed when naphthalic acid is oxidised with KMnO 4 
 (B. 26, 1798). Hydriodic acid and phosphorus reduce it to 2-methyl- 
 iso-phthalic acid, and when heated it becomes 2-aldehydo-iso-phthalic 
 acid, while more complete oxidation converts it into hemi-mellitic acid 
 (B. 29, R. 282). 
 
 Iregenone-di- and tri-earboxylic acids CH 2 [ 4 ]C 6 H 3 /W^^) 2 co 2 H 
 
 U [2jCO.CO 2 H 
 and 
 
 Mono-nuclear, Aromatic Substances, with Unsaturated Side Chains. 
 
 The benzene derivatives thus far considered contain saturated 
 side chains having carbon present in them. To these are attached the 
 compounds having unsaturated side chains e.g. : 
 
 Phenyl-ethylene, Styrol . C,H 6 .CH : CH t Phenyl Acetylene . . C.H S C : CH 
 
 Cinnamyl Alcohol, Styrone . C 8 H S .CH : CH.CH,OH Phenyl Acetylene Alcohol . C 8 H S C : C.CH.OH 
 
 Cinnamyl Aldehyde . . C.H S .CH : CH.CHO Phenyl Acetylene Aldehyde C.H 8 C C.CHO 
 
 Cinnamic Acid . . . C,H 5 .CH : CH.CO.H Phenyl Propiolic Acid . C.H 5 C ; C.CO,H. 
 
 They can, like the unsaturated aliphatic bodies, be converted 
 by numerous additive reactions into saturated compounds, as has 
 frequently been shown in the preceding sections. 
 
 la. OLEFIN-BENZENES. 
 
 For the preparation of the olenn-benzols containing the olefin 
 linkage in the neighbourhood of the benzene nucleus, the secondary 
 
404 ORGANIC CHEMISTRY 
 
 and tertiary phenyl-alkyl-carbinols are particularly suited, and can 
 be easily prepared from the synthetic acidyl-benzols by reduction or 
 by the action of magnesium alkyl-iodides. 
 
 These carbinols are (i) made into chlorides by treatment with HC1 
 at o, and HC1 is split off from the latter by heating with pyridin : 
 
 C 6 H 5 COCH 3 > C 6 H 6 CH(OH)CH 3 > C 6 H 5 CHC1CH 3 > C 6 H 5 CH : CH 2 . 
 
 (2) The addition products obtained from acidyl-benzols or benzol- 
 carboxylic esters split up on heating with excess of AlkMgl (B, 35, 
 2633, 3506) : 
 
 C 6 H 6 COCH 3 
 
 According to the position of the ethylene double linking to the ben- 
 zene nucleus we distinguish A 1 , A 2 , and A 3 olenn-benzols or styrols, 
 differing in density, boiling-point, molecular refraction, and heat of 
 combustion (B. 36, 1628, 3584 ; 37, 2301 ; A. 373, 288). 
 
 On heating with alcoholic potash, the A 2 -styrols are converted into 
 the isomeric A^styrols. This is reversible to some extent (C. 1905, II. 
 1017). 
 
 Styrol, phenyl-ethylene, vinyl-benzol C 6 H 5 .CH : CH 2 , boiling at 
 144, occurs in storax (1-5 per cent.), from which it is obtained upon 
 distillation with water. It also accompanies crude xylene in coal-tar 
 (B. 23, 3169, 3269). It is prepared (i) from chlorethyl-benzol by heat- 
 ing with pyridin to 130 (B. 36, 1632) ; (2) from j3-bromo-hydro- 
 cinnamic acid, heated in NaHO, when it splits up cleanly into CO 2 , 
 BrH, and styrol ; (3) by heating cinnamic acid with lime (B. 23, 3269) 
 or water to 200 ; (4) from phenyl-acetylene by partial reduction with 
 zinc and glacial acetic acid or Na and methyl alcohol ; (5) by the con- 
 densation of acetylene, C 2 H 2 , upon application of heat. (6) From 
 vinyl bromide, benzene, and aluminium chloride (A. 235, 331). (7) It 
 is best obtained from jS-bromo-hydro-cinnamic acid, which is immediately 
 decomposed by a soda solution into styrol, carbon dioxide, and hydro- 
 bromic acid. It is a mobile, strongly refracting liquid, with an agree- 
 able odour. Pure styrolene is optically inactive ; its sp. gr. = 0-925 
 at o. 
 
 Hydriodic acid converts styrolene into ethyl-benzene C 6 H 5 C 2 H 5 ; 
 hydrochloric and hydrobromic acids change it to a-haloid ethyl- 
 benzenes (B. 26, 1709), while with chlorine and bromine it yields 
 a,jS-di-haloid ethyl-benzenes ; chromic acid or nitric acid oxidises it to 
 benzoic acid. 
 
 With xylene and sulphuric acid, styrol forms /?-phenyl-a-tolyl-pro- 
 pane ; and with phenol, oxy-diphenyl-ethane (B. 24, 3889). Nitrous 
 acid converts it into styrol-pseudo-nitrosites C 6 H 5 .C 2 H 3 .(N 2 O 3 ) (B. 29, 
 356). It is polymerised to meta-styrol (C 8 H 8 ) on standing, or in 
 sunlight, whence styrol is regenerated by distillation (C. 1899, II, 
 1117; A. 371,259). 
 
 A. Styrols substituted in the Side Chains. Two series of mono- 
 substituted styrols result from the replacement of vinyl-hydrogen. 
 They are known as a- and co-substituted products : 
 
 a-Bromo-styrol C 6 H 5 Br : CH 2 . 
 co-Bromo-styrol C 6 H 5 .CH.CHBr. 
 
OLEFIN-BENZENES 405 
 
 The a-products result on heating styrol chloride (bromide) alone, 
 with lime, or with alcoholic potash. They possess a penetrating odour, 
 causing tears. They yield aceto-phenone (B. 14, 323) when they are 
 heated with water (to 180) or with sulphuric acid. a-Chloro-styro 
 also results from aceto-phenone chloride when it is digested with alco- 
 holic potash. 
 
 a-Chloro-styrol boils at 190. 
 
 a-Bromo-styrol I5o-i6o (75 mm.). 
 
 to-Chloro-styrol 199. 
 
 a>-Bromo-styrol 108 (20 mm.). 
 
 The CD-products are derived (along with phenyl-acetaldehyde) from 
 the jS-phenyl-a-chloro- (bromo-) lactic acids, upon heating with water. 
 co-Chloro-styrol is obtained also from a>-dichloro-ethyl-benzol with alco- 
 holic potash. o>-Bromo-styrol is formed from dibromo-hydro-cinnamic 
 acid by boiling with water. When they are heated with water, phenyl- 
 acetaldehyde results. They are oils having a hyacinth-like odour. 
 
 See, further, Phenyl-acetylene and Phenyl-propiolic acid. 
 
 Sym. dichloro-styrol C 6 H 5 .CC1 : CHC1 boils at 221 (B. 10, 533), 
 from phenyl-acyl chloride with PC1 5 ; gives diphenyl-pyrazin on heating 
 with ammonia (B. 33, 2654 ; 35, 2294). 
 
 Dibromo-styrol boils at 253 (B. 17, R. 22). 
 
 Di-iodo-styrol, phenyl-acetylene di-iodide, m.p. 76, is obtained from 
 phenyl-acetylene and iodine (B. 26, R. 18). Tri-iodo-styrol, phenyl- 
 tri-iodo-ethylene C 6 H 5 .CI : CI 2 , m.p. 108, is obtained from phenyl- 
 iodo-acetylene and iodine dissolved in CS 2 (B. 26, R. 19). 
 
 Unsym. dichloro-styrol C 6 H 5 CH : CC1 2 , b.p. 225, is found among 
 the products of the reaction of chloral upon benzene in presence of AC1 3 
 (A. 296, 263 ; C. 1900, II. 326). Triehloro-styrol C 6 H 5 CC1 : CC1 2 , b.p. 
 
 235. 
 
 o-Nitro-styrols generally result from the condensation of benzalde- 
 hydes and nitro-methane by means of sodium ethylate or aliphatic 
 amines (B. 37, 4502) ; in the former case there are intermediate pro- 
 ducts in the shape of sodium salts of nitro-alcohols C 6 H 5 CH(OH)CH : 
 NOONa, which easily split off H 2 O and become co-nitro-styrols. On 
 reduction with Al amalgam or zinc dust and acetic acid the nitro-styrols 
 form aryl-acetaldoximes C 6 H 5 CH 2 .CH : NOH (C. 1902, II. 449). 
 
 a>-Nitro-styrol, phenyl-nitro-ethylene C 6 H 5 .CH : CH(NO 2 ), m.p. 58, 
 is obtained by boiling styrol with fuming nitric acid, by condensation 
 of benzaldehyde with nitro-methane CH 3 (NO 2 ) (B. 31, 656 ; 32, 1293 ; 
 A. 325, 7), as well as by the action of fuming nitric acid upon phenyl- 
 iso-crotonic acid (B. 17, 413), or by the action of NO 2 upon cinnamic 
 acid, when the dinitro-compound C 6 H 5 .C 2 H 2 (NO 2 ) 2 .CO 2 H, formed at 
 first, decomposes (B. 18, 2438 ; 29. 357). It possesses a peculiar odour, 
 provoking tears, is readily volatilised in aqueous vapour, and forms 
 yellow needles. Dilute sulphuric acid decomposes it into benzaldehyde, 
 carbon monoxide, and hydroxylamine. It combines with sodium 
 methylate, or ethylate, to form sodium salts C 6 H 5 CH(OR).CH : NOONa, 
 from which CO 2 separates out phenyl-methoxy- and ethoxy-nitro- 
 ethane in the form of yellowish oils, boiling at 136 and 137 (12 mm.) 
 (B. 38, 466). p-Phenylene-bis-nitro-ethylene C 6 H 4 (CH 2 CH.NO 2 ) 2 is 
 obtained from terephthalic aldehyde with nitro-methane (B. 32, 1295). 
 
406 ORGANIC CHEMISTRY 
 
 Phenyl-vinyl-amine, co-amido-styrol C 6 H 5 .CH : CHNH 2 , is very 
 unstable. It is obtained by heating a-amido-cinnamic acid (B. 17, 
 1622), and from oj-nitro-styrol (B. 26, R. 677). 
 
 B. Styrols substituted in the Benzene Nucleus. The three nitro- 
 styrols are produced by the action of a cold soda solution upon the 
 nitro-phenyl-bromo-lactic acids, or by boiling the j3-lactones of the 
 phenyl-bromo-lactic acids with water (B. 16, 2213 ; 17, 595). 
 
 0-, m-, and p-Nitro-styrols NO 2 C 6 H 4 CH : CH 2 melt at +13, -5, 
 and +29. o-Amido-styrol is a very unstable, oily body. m-Amido- 
 styrol, b.p. Ii2-ii5 (12 mm.), is an oil which polymerises with ease. 
 m-Azo-styrol melts at 38 (B. 26, R. 677). p-Amido-styrol, m.p. 81, 
 is formed on heating p-amido-cinnamic acid, and, together with 
 p-amido-cinnamic acid, in the reduction of p-nitro-cinnamic ester 
 (B. 15, 1984). 
 
 C. Styrols substituted both in the benzene nucleus and in the side 
 chain PC1 5 convert o- and p-nitro-aceto-phenones into liquid ortho- 
 and p-nitro-a-chloro-styrol NO 2 .C 6 H 4 .CC1 : CH 2 , melting at 63 (A. 221, 
 
 329). 
 
 o-Nitro-w-ehloro-styrol NO 2 .C 6 H 4 .CH : CHC1, melting at 58, is 
 obtained from o-nitro-cinnamic acid and hypochlorous acid (B. 17, 
 1070). 
 
 o-Amido-ehloro-styrol, melting at 56, yields indol when it is heated 
 to 170 with sodium alcoholate ; see also o-oxy-o>-chloro-styrol. o-, 
 m-, and p, co-Dinitro-styrol melt at 107, 125, and 199 respectively, 
 with decomposition ; see B. 31, 657, 1294 ; C. 1902, II. 449. 
 
 D. Homologous Olefin-benzols. m- and p-Methyl-styrol, vinyl- 
 toluols CH 3 C 6 H 4 CH : CH 2 , b.p. 164 and b.p. 60 ; 4-ethyl-styrol, b.p. 20 
 86 ; 2, 4, 5- and 2, 4, 6-trimethyl-styrol, m.p. 118, b.p. 213 and b.p. 14 
 92 have been prepared mostly by method i (B. 24, 1332 ; 31, 1007 ; 
 35, 2245). For other olefins of the mesitylene series, dimethyl-styrols, 
 see B. 37, 924. 
 
 Propenyl-benzol, iso-allyl-benzol C 6 H 5 .CH : CHCH 3 , b.p. 13 74, from 
 a-chloro-propyl-benzol with pyridin, from cinnamic alcohol by reduc- 
 tion with HI, from o>-bromo-styrol with CH 3 MgI, and from a, /3-ehloro- 
 bromo-propenyl-benzol C 6 H 5 CC1 : CBrCH 3 , a transformation product 
 of bromo-propionyl-benzol C 6 H 5 .COCHBrCH 3 , by reduction with 
 sodium in ether (B. 36, 3033). 
 
 Allyl-benzol C 6 H 5 .CH 2 .CH 2 .CH : CH 2 , b.p. 155, from benzene-allyl 
 iodide and zinc dust (A. 172, 132) or from C 6 H 5 MgBr and allyl bromide 
 (C. 1904, II, 1038). 
 
 Iso-propenyl-benzol, metho-vinyl-benzol C 6 H 5 C(CH 3 ) : CH 2 , b.p. 162, 
 from aceto-phenone or benzoic acid ester with excess of magnesium- 
 methyl iodide, or from C 6 H 5 C(CH 3 ) 2 OMgI with NH 3 ; similarly, metho- 
 propenyl-, metho-butenyl-, and metho-hexenyl-benzols have been pre- 
 pared, boiling at 192, 199, and 210 (20 mm.) respectively. On the 
 elimination of formaldehyde from metho-vinyl-benzol by atmospheric 
 oxidation, see C. 1902, II. 1505. Optically active metho-pentenyl- 
 benzol, b.p. 9 ioo-io3, [a] D 50-3 (B. 37, 653). to-Bromiso-propenyl- 
 benzol C 6 H 5 C(CH 3 ) : CHBr, b.p. 9 106, from dibromo--methyl- 
 cinnamic acid with NaHO. With alcoholic potash and migration of 
 the phenyl group it yields phenyl-alkylene (C. 1907, I. 1201). 
 
 A 2 -Butenyl-benzol C 6 H 5 CH 2 CH : CHCH 3 , b.p. 176, D 15 0-8857, 
 
ACETYLENE BENZENES 407 
 
 n D 1-5109, from benzyl-acetone by reduction and dehydration, or by 
 reduction of phenyl-butadiene with sodium and alcohol. On heating 
 to 180 with alcoholic potash it passes into the isomeric A 1 -butenyl- 
 benzol C 6 H 5 CH : CH.CH 2 .CH 3 , b.p. 189, D 16 0-9124, n D 1-5414, which 
 also results from benzaldehyde treated with propyl-magnesium iodide, 
 and which is reduced by nitrogen and alcohol to n-butyl-benzol, in 
 contrast with A 2 -butenyl-benzol (B. 37, 2310). 
 
 AMso-amenyl-benzol C 6 H 5 CH : CH.CH(CH 3 ) 2 , b.p. 207. AMso- 
 amenyl-benzol C 6 H 5 CH 2 .CH : C(CH 3 ) 2 , b.p. 205 (B. 37, 2314). 
 
 Ib. ACETYLENE BENZENES. 
 
 Phenyl-acetylene, acetenyl-benzene, C 6 H 5 .C ' CH, boiling at 139, is 
 produced (i) when a-bromo-styrolene and (2) aceto-phenone chloride 
 are heated to 130 with alcoholic potash ; (3) also from phenyl- 
 propiolic acid, on heating it with water to 120, or upon distilling the 
 barium or aniline salt (B. 29, R. 797), or the copper salt with steam 
 (A. 342, 222). Phenyl-acetylene is a liquid with an agreeable odour. 
 Like acetylene, it forms a compound with ammoniacal silver solution 
 and with a solution of cuprous chloride, phenyl - acetylene - silver 
 C 6 H 5 .CCAg, white (B. 25, 1096), and phenyl - acetylene - copper 
 C 6 H 5 .C ' C.Cu, light yellow, which dissolves in glacial acetic acid with 
 an orange coloration and formation of the very oxidisable double 
 salt C 6 H 5 C : C.Cu, CH 3 COOCu, and of diphenyl-butenin (A. 342, 
 193). Phenyl-acetylene-sodium C 6 H 5 C ' CNa is formed by the action 
 of sodium upon an ether solution of phenyl-acetylene ; it condenses 
 with aldehydes and ketones to phenyl-acetylene alcohols, with formic 
 ester to phenyl-acetylene-aldehyde, with homologous acid esters or 
 chlorides to phenyl-acetylene-ketones, with chloro-carbonic ester 
 to phenyl-propiolic ester, and with CO 2 to phenyl-propiolic acid. 
 Treated with hydrated sulphuric acid, phenyl-acetylene becomes aceto- 
 phenone, and by boiling with acetic acid or alcohol, and zinc dust, it 
 becomes styrol, with small quantities of diphenyl-butadiene (B. 
 22, 1184). 
 
 Phenyl-chloro-acetylene C 6 H 5 C;CC1, b.p. 14 74. Phenyl-bromo- 
 acetylene C 6 H 5 C = CBr, b.p. 15 96. Phenyl-iodo-acetylene C 6 H 5 C ; CI, 
 b.p. 22 136, are converted by sulphuric acid into the corresponding 
 phenacyl haloids (B. 26, R. 20 ; A. 308, 292). Various aryl-chloro- 
 acetylenes are formed from the corresponding a, jS-dichloro-styrols with 
 alcoholic potash, while metallic sodium forms aryl-acetylenes (B. 33, 
 2654, 3261). 
 
 o-Nitro-phenyl-aeetylene and p-nitro-phenyl-acetylene C 6 H 4 <^ H , 
 
 vNC/2 
 
 melting at 8i-82 and 152, are produced on boiling o- and p-nitro- 
 phenyl-propiolic acid with water. 
 
 o-Amido-phenyl-acetylene C 6 H 4 (NH 2 )C : CH is an oil with an odour 
 resembling that of the indigo vat. It is produced in the reduction of 
 o-nitro-phenyl-acetylene with zinc dust and ammonia, or with ferrous 
 sulphate and potassium hydroxide, and in the decomposition of o-amido- 
 phenyl-propiolic acid. 
 
 Phenyl - methyl - acetylene, phenyl-allylene C 6 H 5 .C ; C.CH 3 , boiling 
 at 185, is produced on boiling phenyl-bromo-propylene with alcoholic 
 potash (B. 21, 276). Phenyl-ethyl-acetylene, boiling at 201, is 
 
4 o8 ORGANIC CHEMISTRY 
 
 obtained from sodium phenyl-acetylide and ethyl iodide, as well as 
 from phenyl-iodo-acetylene and zinc ethide. 
 
 Ic. DlOLEFIN-BENZOLS. 
 
 A. p-Divinyl-benzol C 6 H 4 (CH : CH 2 ) 2 is a liquid with an odour like 
 that of petroleum. It is produced when p-di-a-bromo-ethyl-benzol is 
 heated with quinolin (B. 27, 2528). 
 
 B. Phenyl-butadiene CgHgCH : CH.CH : CH 2 , m.p. -3-5, b.p. 18 
 95, is formed by the action of excess of methyl-magnesium iodide 
 upon cinnamic aldehyde (B. 37, 2310), from cinnamylidene malonic or 
 acetic acid by splitting off CO 2 ; also from the chloride of styryl-methyl- 
 carbinol C 6 H 5 CH : CH.CHC1.CH 3 by boiling with pyridin. It poly- 
 merises on standing, and does so rapidly on heating to 150, forming 
 bimolecular bis-diphenyl-butadiene (C 10 H 10 ) 2 , b.p. 17 221 (B. 37, 2272). 
 Sodium and alcohol reduce phenyl-butadiene to A 2 -butenyl-benzol. 
 With bromine it forms a 1, 4-dibromide C 6 H 5 CHBrCH : CH.CH 2 Br, m.p. 
 94, and with 2Br 2 a tetrabromide C 6 H 5 CHBrCHBr.CHBrCH 2 Br. The 
 dibromide changes with zinc methyl and ethyl into dimethyl and 
 diethyl-butenyl-benzol CgHgCHfAlkJCH : CHCH 2 (Alk). With diazo- 
 acetic ester, phenyl-butadiene combines to form styryl-trimethylene- 
 
 carboxylic ester C 6 H 6 CH : CH.CH</' C 2R (B. 37, 2101). 
 
 An isomeric (P)-phenyl-butadiene and its polymerisation product 
 are formed from cinnamenyl-acrylic acid (cinnamylidene-acetic acid) by 
 heating with barium hydroxide (B. 35, 2649, 2696 ; 36, 1404). 
 
 Phenyl-methyl-butadiene C 6 H 5 CH : CH.C(CH 3 ) : CH 2 , b.p. 32 124, 
 and phenyl-methyl-pentadiene C 6 H 5 CH,: CH.C(CH 3 ) : CHCH 3 , b.p. 21 
 133, from benzal-acetone, with magnesium methyl and ethyl iodide 
 by method 2 (B. 35, 2651). Phenyl-pentadiene C 6 H 5 CH : CH.CH : 
 CH.CH 3 , b.p. 16 116. Phenyl-hexadiene C 6 H 5 CH : CH.CH : CH.CH 2 CH 3 , 
 b.p. 16 128, from cinnamic aldehyde and ethyl- or propyl-magnesium 
 iodide respectively (B. 40, 1768). 
 
 Trimethyl-phenyl-allene C 6 H 5 (CH 3 )C : C : C(CH 3 ) 2 , b.p. 20 108, a 
 strongly refractive liquid with an odour resembling lemon, is formed 
 by the action of C 6 H 5 MgBr upon mesityl oxide. On oxidation with 
 KMnO it yields aceto-phenone, and on reduction with Na and alcohol 
 A 2 -hexenyl-benzol (B. 37, 2305). 
 
 Id. OLEFIN- ACETYLENE-BENZOLS, like iso-propenyl-phenyl-aeetylene 
 C 6 H 5 C C.C(CH 3 ) : CH 2 , b.p. 7 88, and iso-butenyl-phenyl-acetylene 
 C 6 H 5 C i C.C(CH 3 ) : CH.CH 3 , b.p. 9 103, have been prepared from phenyl- 
 acetylene alcohols, by splitting off water with sulphuric acid or potas- 
 sium bisulphate (C. 1905, II. 1018). 
 
 Ha. OLEFIN-PHENOLS. 
 
 Various representatives of this class occur in the vegetable kingdom : 
 chavicol, chavibetol, estragol, anethol, eugenol, safrol, asarone, apiol, 
 etc. All are phenol-like derivatives of allyl- and iso-allyl- or propenyl- 
 benzene. The allyl fatty derivatives occurring in the vegetable kingdom 
 were mustard oil (I. 423) and oil of garlic (I. 150). 
 
OLEFIN-PHENOLS 409 
 
 A. Olefin -monoxy- benzols. o- Vinyl -phenol CH 2 : CH.C 6 H 4 OH, 
 
 m.p. 29, b.p. 15 108, smells like phenol, and is formed by slow distillation 
 of o-cumaric acid in a vacuum (B. 41, 367). 
 
 m-Vinyl-phenol CH 2 : CH.C 6 H 4 .OH, b.p. 115 (16 mm.), is obtained 
 from m-amido-styrol. o-, m-, and p-vinyl-anisols CH 2 : CH.C 6 H 4 .O.CH 3 
 boiling at 83 (n mm.), 90 (14 mm.), and 91 (13 mm.) respectively, 
 are easily polymerised oils, obtained from the corresponding methoxy- 
 aceto-phenones by method I ; the o- and p-derivatives have also been 
 obtained from the methoxy-cinnamic acids (B. 11, 515 ; 36, 3587). 
 
 o-Oxy-co-chloro-styrol HO[2]C 6 H 4 .CH : CHC1, m.p. 54, is obtained 
 from o-amido-oj-chloro-styrol. Caustic potash converts it into cuma- 
 rone (q.v.). o-Thio-cu-ehloro-styrol HS.C 6 H 4 .CH : CHC1, see Benzo- 
 thiophene. 
 
 Allyl- and Propenyl-phenols. A very common property of the 
 allyl-phenols is their rearrangement, induced by hot alcoholic potash, 
 into isomeric-propenyl compounds : 
 
 CH 3 O.C 6 H 4 .CH 2 .CH : CH 2 -- > CH 3 O.C 6 H 4 .CH : CH.CH 3 Anethol. 
 
 (CH 3 0) 2 C 6 H 3 .CH 2 .CH:CH 2 -^(CH 3 0) 2 C 6 H 3 .CH:CH.CH 3 M ^^ 
 Safrol (CH 2 2 )C 6 H 3 .CH 2 .CH : CH 2 - > (CH 2 O 2 )C 6 H 3 .CH : CH.CH 3 Iso-safrol. 
 
 The propenyl derivatives are distinguished from their allyl deriva- 
 tives by higher specific gravities, higher melting-points, and greater 
 refractive power (B. 22, 2747 ; 23, 862). When the propenyl com- 
 pounds are acted upon by nitrous acid, in glacial acetic acid, they yield 
 di-iso-nitroso-peroxides, derivatives of a-diketones (see Anethol). The 
 allyl- and propenyl-phenols, when carefully oxidised with potassium 
 permanganate, yield phenol-glycols and phenol-glyoxylic acids ; and, on 
 oxidation with ozone, oxy-benzaldehydes and oxy-phenyl-acet- 
 aldehydes (B. 41, 2751). Mercuric acetate oxidises the propenyl com- 
 pounds to glycols, with elimination of mercuric acetate. The allyl 
 bodies form only addition products, from which the allyl-phenols can 
 be regenerated by decomposition with acids or by reduction (B. 36, 
 3577 ; C. 1906, II. 119 ; B. 42, 1502). By boiling with concentrated 
 formic acid the propenyl compounds are resinified, while the allyl 
 compounds remain unchanged (B. 41, 2185). The iodo-hydrins of 
 the propenyl compounds, on treatment with AgNO 3 or HgO, form 
 aldehydes, with migration of the aromatic residue. Thus anethol 
 forms p-methoxy-hydratropic aldehyde CH 3 OC 6 H 4 CH(CH 3 )CHO. In 
 the dibromides of the propenyl compounds the bromine atom adjoining 
 the phenyl group is easily movable ; they can therefore be converted 
 into ketones by treatment with two molecules sodium methylate, e.g. 
 anethol dibromide into anisoyl-ethyl-ketone. This cannot be done in 
 the case of the allyl dibromides. 
 
 Chavicol, p-allyl-phenol CH 2 : CH.CH 2 [4]C 6 H 4 OH, b.p. 237, 
 occurs in the oil obtained from the leaves of Chavica Betle. Also in betel 
 oil and ethereal bay oil. It is a colourless oil, with peculiar odour, and 
 its aqueous solution is coloured blue by a drop of ferric chloride. 
 Methyl-chavicol boils at 226, and ethyl-chavicol boils at 232 (B. 23, 862). 
 
 Estragol, methyl-chavicol, occurs in tarragon oil and other ethereal 
 
410 ORGANIC CHEMISTRY 
 
 oils (B. 27, R. 46). It boils at 215 (compare B. 27, R. 46 ; 29, 544 ; 
 C. 1899, I- 1196). Synthetically it is formed by the action of allyl 
 bromide upon p-methoxy-phenyl-magnesium bromide (C. 1904, II. 
 1038). It changes into anethol when heated with alcoholic potash. 
 
 p-Anol, p-propenyl-phenol CH 3 .CH : CH[4]C 6 H 4 OH, m.p. 92, is 
 prepared by heating anethol with caustic alkali (A. Suppl. 8, 88) ; or, 
 synthetically, from p-oxy-benzaldehyde and excess of ethyl-magnesium 
 bromide (C. 1908, I. 1624). 
 
 Anethol, p-propenyl-anisol CH 3 .CH : CH[4]C 6 H 4 .O.CH 3 , m.p. 21, 
 and b.p. 232, occurs in anise oil, from the seed of Pimpinella anisum, 
 in that from the seed of Illicium anisatum, in the fruit of Anethum 
 faniculum, and in fennel and tarragon oils. It is also formed from 
 methyl-chavicol (see above). It has been obtained synthetically from 
 ethyl Mg iodide and anisaldehyde (B. 37, 4188) and from /?-p-methoxy- 
 phenyl-methacrylic acid by heating ; this would prove that its con- 
 stitution is that of p-propenyl-anisol (B. 10, 1604). Chromic acid 
 oxidises it to anisic and acetic acids, while dilute nitric acid changes it 
 to anisic aldehyde. Methoxy-phenyl-glyoxylic acid is produced on 
 treating it with potassium permanganate ; anisyl-propenyl-glycol on 
 treating it with mercuric acetate ; and methoxy-hydratropic aldehyde 
 by treatment with iodine and mercuric oxide. With HNO 2 it unites 
 according to the conditions either to form anethol-pseudo-nitrosite, 
 anethol nitrite CH 3 OC 6 H 4 CH(NO).CH(NO 2 )CH 3 , m.p. 121, or p-meth- 
 oxy-phenyl-methyl-glyoxime CH 3 OC 6 H 4 C(NOH)C(NOH)CH 3 , or its 
 peroxide. The anethol nitrite splits off hyponitrous acid on treatment 
 with acetyl chloride or sodium methylate, and becomes jS-nitro- 
 anethol CH 3 OC 6 H 4 CH : CH[NO 2 ].CH 3 , m.p. 47, yellow needles. 
 
 Anethol-nitroso-ehloride CH 3 OC 6 H 4 CHC1.CH(NO).CH 3 , m.p. 128 
 (A. 332, 318). o- and m-Propenyl-anisol, b.p. 220 and 227 (B. 29, 
 R. 644 ; 36, 1188). 
 
 o-, m-, and p-iso-propenyl-anisols boil at 199, 215, and 222 respec- 
 tively. They are formed from the anisol-carboxylic esters with 
 CH 3 MgI (C. 1904, II. 593 ; 1908, I. 1624 H. 595). Like the propenyl 
 compounds, the iso-propenyl compounds are easily reduced with Na 
 and alcohol. On oxidation with KMnO 4 oxy-aceto-phenones are 
 generated. Treated with AgNO 3 their iodo-hydrins yield ketones, with 
 migration of the aromatic residue. 
 
 B. Olefin-dioxy-benzols. Of this group it is the olefin-3, 4-dioxy- 
 benzols which are almost exclusively known. They usually occur, as 
 ethers, in plants, or are obtained by the breaking down of plant acids. 
 
 Free vinyl-pyro-cateehin (HO) 2 [3, 4]C 6 H 2 CH : CH 2 seems to be 
 unstable and easily polymerised. Its carbonate CO(O 2 )C 6 H 3 CH : CH 2 , 
 m.p. 66, is formed by the dry distillation of 3, 4-dioxy-benzal-malonic 
 carbonate (B. 41, 4153). 
 
 Hesperetol, vinyl-^ ^-guaiacol c ^o[4]} C6H3 ' CH : CH2 ' m - p - 57 ' is 
 produced in the dry distillation of calcium iso-ferulate (B. 14, 967). 
 Vinyl-3,4-pyro-catechin-methylene ether CH 2 <^? \c 6 H 3 CH : CH 2 ,b.p. 15 
 
 108, from piperonal and magnesium-methyl iodide (B. 36, 3595). 
 
 Allyl-3, 4-pyro-cateehin (HO) ,[3, 4]C 6 H 3 CH 2 .CH : CH 2 , m.p. 49, 
 b.p. 4 139, has been found in the oil of Java betel leaves. It possesses 
 
OLEFIN-PHENOLS 411 
 
 a feeble odour, recalling creosote ; its alcoholic solution is coloured 
 deep green by ferric chloride (C. 1907, II. 1741). More frequently the 
 ethers of allyl-pyro-catechin are found among the ethereal oils. Of 
 these substances, special mention should be made of eugenol and safrol, 
 the foundation materials for the artificial production of the perfumes 
 vanillin and heliotropin. 
 
 Eugenol, allyl - 4, 3 - guaiacol, eugenic acid, carnation acid 
 
 3 M\C 6 H 3 .CH 2 .CH:CH 2 , is an aromatic oil, boiling at 247. 
 CH 3 O[3J J 
 
 It is coloured blue by ferric chloride. It occurs in the oil from Eugenia 
 caryophyllata, in that from Eugenia pimenta, etc. Sodium amalgam 
 reduces coniferyl alcohol to eugenol (B. 9, 418). Potassium perman- 
 ganate oxidises it to vanillin and vanillinic acid. Heated with excess 
 of alcoholic potash, it is transposed into the isomeric iso-eugenol. See 
 B. 27, 2455 ; 28, 2082, for the derivatives of eugenol. 
 
 Chavibetol, betel-phenol, allyl-^^-guaiacol J* j^ }c 6 H 3 .CH 8 .CH : CH 2J 
 
 ^-ti 3 UL4j J_ 
 
 boiling at 254, occurs in the ethereal oil obtained 'from the leaves of 
 Piper Betle (J. pr. Ch. 2, 39, 349 ; B. 23, 862). 
 
 Eugenol-methyl ether, allyl-^, ^-veratrol (CH 3 O) 2 [3, 4]C 6 H 3 .CH 2 . 
 CH : CH 2 , boiling at 244, is present in paracoto oil (A. 271, 304), in 
 the ethereal oil from Asarum europceum (B. 21, 1060), and in bay oil. 
 It has been synthetically prepared from pyro-catechol-dimethyl ether, 
 allyl iodide, and zinc dust (B. 28, R. 1055). Chromic acid oxidises it 
 to dimethyl-proto-catechuic acid or vetraric acid. It forms iso-eugenol- 
 methyl ether when heated with alcoholic potash. It also results when 
 sodium eugenol or potassium chavibetol is treated with methyl iodide 
 (J.pr. Ch. 2,39,353). 
 
 Safrol, shikimol, allyl - 3, 4 - pyro - catechol - methylene ether 
 
 CH 2 /^ 3 Hc 6 H 3 .CH 2 .CH : CH 2 , melting at 8 and boiling at 232, is 
 ^-'i/j.j J 
 
 present in the oil of Sassafras officinalis and in that of Illicium religiosum 
 or Shikimino-ki. Potassium permanganate oxidises it to methylene- 
 p, m-dioxy-benzyl-glycol, homo-piper onylic acid and piperonoyl-car- 
 boxylic acid, which are further oxidised to piperonal and piperonylic 
 acid (B. 24, 3488 ; 28, 2088). Nitrosites (see B. 28, R. 1004). 
 
 Propenyl-3, 4-pyro-eateehin, isomeric with allyl-3, 4-pyro-catechin, is 
 formed in small quantities by transformation of proto-catechin alde- 
 hyde with excess of ethyl-magnesium bromide (C. 1908, I. 1624). The 
 propenyl-pyro-catechol ethers : iso-eugenol, iso-eugenol-methyl ether and 
 iso-safrol, isomeric with the previously described allyl-pyro-catechol 
 ethers, are derived from it. 
 
 Iso-eugenol **j: 4 Hc 6 H 3 CH : CH.CH 3 , boiling at 260, is formed 
 
 J 
 
 when homo-ferulic acid is distilled with lime, and upon heating eugenol 
 with caustic potash or sodium alcoholate in amyl alcohol (B. 27, 2580 ; 
 C. 1897, I. 384). Synthetically, from vanillin and ethyl-magnesium 
 bromide (C. 1908, I. 1625). On oxidation it yields vanillin, a reaction 
 which is used industrially on a large scale. 
 
 Iso-eugenol-methyl ether, propenyl-%, ^-veratrol, boiling at 263, 
 has been found in the oil of Asarum arifolium, and results upon heating 
 eugenol-methyl ether with alcoholic potash (B. 23, 1165). Also from 
 methyl-vanillin and C 2 H 5 MgBr (C. 1908, I. 1625). Potassium perman- 
 
4 i2 ORGANIC CHEMISTRY 
 
 ganate oxidises it to veratroyl-carboxylic acid and veratric acid (B. 24, 
 2877). It yields a glycol, melting at 88, when it is carefully oxidised. 
 
 Iso-safrol CH 2 <^ 3 ^C 6 H 3 .CH : CH.CH 3 , boiling at 249, is obtained 
 
 from safrol by heating it with alcoholic potash, or with dry sodium 
 ethylate. Synthetically, from piperonal and C 2 H 5 MgI (C. 1904, 
 II. 1566). Potassium permanganate oxidises it to a glycol (B. 36, 
 3580), melting at 101, and piperonoyl-carboxylic acid. Chromic acid 
 changes it to piperonal, artificial heliotropine, from which it can be 
 again re-formed by condensation with propionic acid, and the splitting 
 off of CO o from the methylene-homo-caffeiic acid which is first pro- 
 duced (B. 29, R. 382). Sodium and alcohol reduce it to dihydro-safrol 
 and m-propyl-phenol (B. 23, 1160) . Pseudo-nitrosite, m.p. 128 (A. 332, 
 
 331). 
 
 C. Olefln - trioxy - benzols. Asarone, propenyl - 2, 4, 5 - trimethoxy- 
 benzene (CH 3 O) 3 [2, 4, 5]C 6 H 2 .CH : CH.CH 3 , melting at 67 and boiling 
 at 296, separates from the ethereal oil of the root of Asarum europceum, 
 in which it is present together with terpenes -and eugenol. Also from 
 calmus oil (B. 35, 3190), and synthetically from asaryl-aldehyde, pro- 
 pionic anhydride, and sodium propionate (B. 32, 289). 
 
 Potassium permanganate oxidises it to trimethoxy-benzaldehyde 
 and a trimethoxy-benzoic acid, which breaks down into CO 2 and oxy- 
 hydroquinone-methyl ether when it is distilled with lime (B. 23, 2294). 
 
 Elemicin, ally 1-3, 4, $-trimethoxy-benzol (CH 3 O) 3 [3, 4, 5]C 6 H 2 CH 2 . 
 CH : CH 2 , b.p. 10 I44-I47, is the chief constituent of Manila elemi oil 
 (B. 41, 1768). On oxidation with ozone, it yields trimethyl-homo- 
 gallic aldehyde and trimethyl-homo-gallic acid ; with KMnO 4 , in acetone 
 solution, it forms trimethyl-gallic acid. On heating with alcoholic 
 potash it is converted into the corresponding propenyl compound, iso- 
 elemicin, b.p. 10 I53-I56, which is geometrically isomeric with asarone. 
 Iso-elemicin is oxidised by ozone to trimethyl-gallic aldehyde or acid 
 (B. 41, 1918, 2183). 
 
 Myristicin, butenyl - 3, 4, 5 - trioxy - benzol - methyl - methylene ether 
 
 c eH 2 C 4 H 7 , melting at 30, results upon treating the high-boil- 
 . 
 ing portions of nutmeg oil and mad oil with metallic sodium. It is also 
 
 obtained with apiol from the seed of French parsley (B. 36, 3451). 
 Alcoholic potash transposes it into the propenyl compound iso- 
 myristicin, m.p. 45, which, on oxidation with permanganate, gives a 
 methylene-methyl-pyrogallic aldehyde and methylene-methyl -gallic 
 acid (B. 36, 3446). Nitrosites, see C. 1905, II. 482. 
 
 D. Olefln - tetraoxy - benzols. Apiol, allyl-apionol-dimethyl-methyl- 
 ene ester (CH 3 O) 2 (CH 2 O 2 ).C 6 H.CH 2 .CH : CH 2 , melting at 30 and boil- 
 ing at 294, occurs in parsley seeds and in Petroselinum sativum. 
 Potassium permanganate oxidises it to ethers of a tetraoxy-benzal- 
 dehyde and a tetraoxy-benzoic acid. See also ApinoL Boiling alco- 
 holic potash changes it to the isomeride isapiol, m.p. 56, b.p. 304 (B. 
 25, R. 908). An apiol, b.p. 162 (n mm.), differing from the preced- 
 ing only in the relative position of the methylene and methyl groups, 
 occurs in the oil from Anethum graveolens (B. 29, 1800), in sea-fennel 
 oil (C. 1909, II. 1334), and m matico oil together with, parsley apiol. By 
 alcoholic potash it is converted into the isomeric dilliso-apiol, m.p. 44, 
 
PHENYL-OLEFIN ALCOHOLS 413 
 
 (C. 1904, II. 525) l-Allyl-2, 3, 4, 5-tetramethoxy-benzol (CH 3 O) 4 
 [2, 3, 4, 5]C 6 HCH 2 CH : CH 2 , m.p. 25, has been isolated from French 
 parsley seed. On oxidation with KMnO 4 it yields tetramethoxy-ben- 
 zoic acid (B. 4-1, 2761). 
 
 lib. Aeelylene-anisol CH ; CC 6 H 4 OCH 3 , b.p. u 85-88, from a, ft- 
 dichloro-p-methoxy-styrol with sodium (B. 36, 915). 
 
 Acetylene-phenetol CH ; C.C 6 H 4 O.C 2 H 5 (A. 269, 13). 
 
 Ilia. PHENYL-OLEFIN ALCOHOLS WITH THEIR OXIDATION PRODUCTS. 
 
 The chemistry of the phenyl-olefin alcohols, aldehydes, and ketones 
 has not been fully developed. Their phenol-like derivatives will be 
 discussed in immediate connection with the most important repre- 
 sentatives of the class. The division in detail of the material into poly- 
 alcohols and their oxidation products, as was carried out with uni- 
 nuclear benzene derivatives having oxygen-containing side chains, is 
 not feasible with uni-nuclear benzene derivatives having unsaturated 
 oxygen-containing side chains, because, at present, no representatives 
 have been prepared of many classes of compounds which can be de- 
 duced theoretically. The bodies belonging here will, therefore, be 
 introduced at the proper places in connection with the simple phenyl- 
 olefin alcohols, and their oxidation products. 
 
 10. Phenyl-olefin Alcohols. The two phenyl-vinyl alcohols, 
 possible theoretically, are not known, and apparently are incapable 
 of existence. The a-haloid styrols become aceto-phenone upon re- 
 placing their halogen atom by hydroxyl, while the j3-haloid styrols yield 
 phenyl-acetaldehyde : 
 
 a-Chloro-styrol C 6 H 6 .CC1 : CH 8 ^-- C 8 H 6 .CO.CH 3 Aceto-phenone. 
 w-Bromo-styrol C 6 H 5 .CH : CHBr > C 6 H 6 .CH 2 CHO Phenyl-acetaldehyde. 
 
 However, the corresponding ethyl ethers have been prepared : 
 
 jS-Phenyl-vinyl-methyl ether, b.p. 2io-2i3, and jS-phenyl-vinyl- 
 ethyl ether C 6 H 5 .CH : CH.O.C 2 H 5 , b.p. 24 115, are formed from co- 
 chloro-styrol and from phenyl-acetylene by heating with sodium alcohol- 
 ate (A. 308, 270 ; C. 1904, I. 720). 
 
 a-Phenyl-vinyl-methyl ether C 6 H 5 C(O.CH 3 ) : CH 2 , b.p. 197, from 
 /2-methoxy-cinnamic acid. 
 
 a-Phenyl-vinyl-ethyl ether C 6 H 5 C(OC 2 H 5 ) : CH 2 , ,b.p. 209, is ob- 
 tained by splitting off alcohol from aceto-phenone-acetal, with heat, 
 and is rearranged, by heating under pressure, into isomeric phenyl 
 ethyl ketone (B. 29, 2931). By saponification these ethers are con- 
 verted into phenyl-acetaldehyde and aceto-phenone (C. 1904, I. 719). 
 
 /3-Phenyl-vinyl-phenyl ether C 6 H 5 CH : CH.O.C 6 H 5 , b.p. 7 158, by 
 distillation of a-phenoxy-cinnamic acid. On heating with alcoholic 
 potash to about 200, the phenol residue is displaced, and, among other 
 products, jS-phenyl- vinyl-ethyl ether is formed (B. 38, 1962). 
 
 Cinnamyl alcohol, styrone, y-phenyl-allyl alcohol C 6 H 5 .CH : CH 
 CH 2 OH, m.p. 33 and b.p. 250, occurs as cinnamic ester in liquid 
 storax, the sap of the Liquidambar orientalis tree, found in the south- 
 western portion of Asia Minor. It is prepared artificially by reduction 
 of cinnamic aldehyde diacetate (C. 1905, II. 672). When oxidised it 
 becomes cinnamic aldehyde, cinnamic acid, and benzoic acid ; see 
 also Stycerine. Styryl-amine C 6 H 5 .CH : CH.CH 2 NH 2 , b.p. 236 (B. 26, 
 
414 ORGANIC CHEMISTRY 
 
 1858 ; C. 1906, II. 1420). Styryl-iso-cyanate C 6 H 5 CH : CH.NCO, b.p. 12 
 107, see C. 1909, I. 1655. a-Phenyl-allyl alcohol C 6 H 5 CH(OH).CH : 
 CH 2 , b.p. 25 114, from phenyl-magnesium bromide and acrolein (B. 
 39, 2554). 
 
 Styryl-methyl-earbinol, y-phenyl-a-methyl-allyl alcohol C 6 H 5 .CH : 
 CHCH(CH 3 )OH, b.p. 21 144, from cinnamic aldehyde, with magnesium- 
 methyl iodide (B. 35, 2649, 3186). 
 
 ib. Oxy-phenyl-olefin Alcohols. j8-Anisyl-/?-methyl-vinyl alcohol 
 CH 3 OC 6 H 4 C(CH 3 ) : CHOH, m.p. 79, b.p. 14 175, is formed from 
 estragol dibromide by successive treatment with potassium acetate 
 and alcoholic potash, with simultaneous molecular transposition (C. 
 1907, II. 1910) : 
 
 j CH 3 OC 6 H 4 CH 2 CHBr.CH 2 Br ^ CH 3 OC 6 H 4 C(CH 3 ) : CHOH 
 
 1 CH 3 OC 6 H 4 CH 2 CH(OCOCH 3 ).CH 2 Br 4- CH 3 OC 6 H 4 CH(CH 3 ).CHO. 
 
 On distillation at ordinary pressures, and under the influence of 
 acids, the alcohol transposes into p-methoxy-hydratropic aldehyde. 
 With sodium methylate, and dimethyl sulphate, the corresponding 
 methyl ethyl is formed, b.p. 262, which is also obtained from anethol- 
 methyl-iodo-hydrin by treatment with HgO, with migration of the 
 aromatic residue (C. 1907, II. 1789) : 
 
 CH 3 OC 6 H 4 CH(OCH 3 ).CHI.CH 3 -- > CH 3 OC 6 H 4 (CH 3 ) : CHOCH 3 . 
 
 Cumarone CeH^r^X _ _| is the inner anhydride of o-oxy- 
 
 phenyl-vinyl alcohol. It will be described later under the heterocyclic 
 compounds. 
 
 Glyco-o-eumaro-aleohol C 6 H n O 5 .O.C 6 H 4 .CH : CH.CH 2 OH, m.p. 
 115, has been formed from glyco-o-cumaraldehyde (see below). 
 
 Sec. methyl- o-eumaro- alcohol HO.C 6 H 4 .CH : CH.CH(OH)CH 3 , 
 m.p. 47. See Methyl-o-cumaro-ketone. 
 
 Tertiary dimethyl- and diethyl - o - eumaro - alcohol anhydride 
 
 fCH:CH 
 C 6 Hj , b.p. u 93 and b.p. 15 127, from cumarin with 
 
 \O - C(Alk) 2 
 magnesium-methyl, and ethyl, iodides (B. 37, 494). 
 
 Coniferyl alcohol, m-methoxy-p-oxy-styrone c ^^ 4 Hc 6 H 3 .CH : CH. 
 
 CH 2 OH, melting at 73, is formed from coniferin (q.v.), which emulsin 
 decomposes into glucoses and coniferyl alcohol. Vanillin results from 
 its oxidation, and eugenol from its reduction. 
 
 Cubebin CH 2 ^^\C 6 H 3 .CH : CH.CH 2 OH, melting at 125, is found 
 
 in cubebs, the fruits of Piper cubeba. 
 
 ic. Phenyl-aeetylene alcohols are formed by the condensation of 
 sodium-phenyl-acetylene, in ethereal suspension, with trioxy-methylene, 
 and the homologous aldehydes, or by the action of caustic alkali upon 
 a mixture of ketones, with phenyl-acetylene. Also from phenyl-pro- 
 pargyl-aldehyde, and phenyl-acetylene ketones, with alkyl-magnesium 
 haloids: phenyl-acetylene alcohol C 6 H 5 C i CCH 2 OH, b.p. 16 139; 
 phenyl-aeetylene-methyl-earbinol C 6 H 5 C ; C.CH(OH)CH 3 , b.p. 29 149; 
 phenyl-acetylene-dimethyl-carbinol C 6 H 5 C ' C(OH)(CH 3 ) 2 , m.p. 53; 
 omanthylidene-phenyl-earbinol CH 3 [CH 2 ] 4 C ; CCH(OH)C 6 H 5 , b.p. 16 
 
PHENYL-OLEFIN ALDEHYDES 415 
 
 181, from sodium-oenanthylidene with benzaldehyde (B. 39, 2594 ; 
 .1901,11.25; 1902,1.619,1319; 1905,11.1018; 1907,1.561). 
 
 2a. Phenyl-olefln Aldehydes. Cinnamic aldehyde, f$-phenyl-acroleln 
 C 6 H 5 .CH : CH.CHO, boiling at 247, forms the chief constituent of 
 cinnamon oil from Cinnamomum ceylanicum, and the oil from Persea 
 Cassia, from which it can be extracted with acid sodium sulphite. The 
 first product is the double derivative C 6 H 5 .CH : CH.CH(OH)SO 3 K, 
 which combines with a second molecule of mono-potassium sulphite 
 to yield C 6 H 5 .CHSO 3 K.CH 2 .CH(OH).SO 3 K+2H 2 O, which dissolves 
 with difficulty (B. 24, 1805 ; 31, 3301). 
 
 The aldehyde results from the oxidation of cinnamyl alcohol, in the 
 dry distillation of a mixture of the lime salts of cinnamic and formic 
 acids, and by the action of hydrochloric acid gas or sodium hydrate 
 (B. 17, 2117), or sodium ethylate (B. 20, 657) upon a mixture of benz- 
 aldehyde and ace t aldehyde. 
 
 Cinnamic aldehyde is a colourless, aromatic oil, which distils readily 
 in aqueous vapour. When exposed to the air it oxidises to cinnamic 
 acid. It adds chlorine and bromine very readily. The dihaloid ad- 
 dition products change with ease into a-monochloro- and a-mono- 
 bromo-cinnamie aldehydes C 6 H 5 .CH : CX.CHO, melting at 35 and 72 
 (B. 24, 246). 
 
 Cinnamic aldehyde chloride C 6 H 6 CH : CH.CHC1 2 , m.p. 54, b.p. 30 
 143, behaves like an acid chloride, but combines with chlorine to the 
 phenyl-tetrachloro-propane C 6 H 5 CHC1.CHC1.CHC1 2 , which is stable in 
 water (C. 1903, I. 457, 1344). 
 
 a and jS-Trithio-cinnamie aldehyde melt at 167 and 213 (B. 24, 
 
 Hydro-einnamide (C 9 H 8 ) 3 N 2 melts at 106, or at 131 when anhydrous 
 (C. 1898, I. 181). 
 
 Cinnamic aldehyde-phenyl-hydrazone C 6 H 5 .CH : CH.CH(N 2 H.C 6 H 5 ) 
 melts at 168. The syn-oxime melts at 138-5. 
 
 Iso-quinolin is produced when the latter is heated with P 2 O 5 (B. 27, 
 2795) . By the action of nitrous gases upon cinnamic aldehyde the chief 
 
 product obtained is phenyl-nitro-isoxazol O.N : C(C 6 H 5 .)C(NO 2 ) : Ctl 
 (A. 328, 196). 
 
 Nitro-cinnamic aldehydes are obtained from the aldehydes of the 
 nitro-phenyl-lactic acids. o-, m-, and p-Nitro-cinnamic aldehydes 
 melt at 127, 116, and 141 (B. 18, 2335). 
 
 a-Methyl-cinnamic aldehyde C 6 H 5 .CH : C(CH 3 )CHO (B. 19, 526, 
 1248). 
 
 y-Benzyl-crotonic aldehyde (pheno - pentenal) C6H 5 CH 2 CH 2 CH : 
 CHCHO, b.p. 13 139, from hydro-cinnamic aldehyde with acetaldehyde 
 (B. 31, 1993). 
 
 2b. Oxy-phenyl-olefin Aldehydes. o-Cumaric aldehyde, o-oxy 
 cinnamic aldehyde HO[2]C 6 H 4 .CH : CH.CHO, melting at 133, is pro- 
 duced by the action of emulsin upon glyco-o-cumaric aldehyde C 6 H 11 O 5 . 
 O.C 6 H 4 .CH : CH.CHO, melting at 199, the condensation product of 
 helicin (q.v.) and acetaldehyde (B. 20, 1931). It occurs as methyl ether 
 in the oil of cassia (B. 28, R. 386). 
 
 p-Methoxy-einnamic aldehyde, b.p. 14 170, has been found in tarra- 
 gon oil (C. 1908, I. 1057). 
 
416 ORGANIC CHEMISTRY 
 
 m- and p-Oxy-cinnamic-aldehyde-o-acetic acid COOH.CH 2 O.C 6 H 4 . 
 CH : CH.CHO (B. 19, 3049). 
 
 Piperonyl-aeroleln (CH 2 O 2 ) [3, 4]C 6 H 3 CH : CH.CHO, melting at 
 70, is obtained from piperonal, acetaldehyde, and sodium hydroxide 
 (B. 27, 2958) ; see Piperic acid. 
 
 3. Phenyl-diolefln Aldehydes. o-Nitro-cinnamylidene-acetaldehyde 
 NO 2 C 6 H 4 .CH : CH.CH : CH.CHO melts at 153 (B. 17, 2026). 
 
 40. Phenyl-olefln Ketones. The phenyl-olefm ketones are readily 
 obtained by the condensation of aromatic aldehydes with aliphatic 
 ketones, which, besides carbonyl, contain CH 3 or CH 2 R groups ; from 
 mixed ketones, phenyl-olefin ketones, with normal C-chains, are 
 usually obtained on using NaHO as means of condensation, whereas 
 HC1 gives a branched chain (cp. B. 35, 3088, 3549). Excess of benz- 
 aldehyde yields dibenzylidene ketones : 
 
 C,H 6 CH : CHCOCH 3 < CH 3 COCH 3 > C 6 H 5 CH : CHCOCH : CHC 6 H 6 . 
 
 Benzal-acetone, benzylidene - acetone, styryl - methyl - ketone C 6 H 5 . 
 CH : CH.CO.CHg, melting at 41 and boiling at 262, is produced in 
 the distillation of calcium cinnamate and acetate, as well as in the 
 condensation of benzaldehyde and acetone with dilute sodium 
 hydroxide (A. 223, 139). Also in small quantities by the action of 
 CH 3 MgI upon cinnamic acid nitrite (C. 1906, II. 48). 
 
 It dissolves with an orange-red colour in sulphuric aid. With 
 mercaptans, it combines to form mercaptols, which add a third molecule 
 of mercaptan to the olefin linkage C 6 H 5 CH(SR)CH 2 C(SR) 2 CH 3 (B. 35, 
 804). 
 
 With alcoholic S 2 Am it gives a dimeric benzal-thio-acetone (C 10 H 10 S) 2 , 
 m.p. 132, which, with water, acids, and salts, gives well-crystallised 
 addition compounds (B. 40, 2982). 
 
 Benzal-aeetone-phenyl-hydrazone, m.p. 156, easily transposes into 
 i, 6-diphenyl-3-methyl-pyrazolin (B. 20, 1099). Oxime, m.p. 115 
 (B. 20, 923). On boiling with sodium hypochlorite, benzal-acetone is 
 broken up into chloroform and cinnamic acid. On reduction, we get 
 benzyl-acetone and, by the junction of two molecules of the olefin 
 ketone, diphenyl - octadiones. Similar behaviour is shown by the 
 homologues of benzal-acetone, on its reduction (B. 35, 968, 3089). 
 Benzal-acetoxime is reduced by Na and alcohol to l-phenyl-3-amino- 
 butane C 6 H 5 CH 2 CH 2 CH(NH 2 )CH 3 , by zinc dust and glacial acetic acid, 
 only, to i-phenyl-3-amino-butene C 6 H 5 CH : CHCH(NH 2 )CH 3 (B. 36, 
 2997) ; the latter is split up by ozone into benzaldehyde and a-amido- 
 propionic aldehyde (B. 37, 615). 
 
 o- and p-Nitro-benzal-aeetone, formed by nitrifying benzal-acetone, 
 melt at 60 and 110 respectively. The o-body passes readily into 
 indigo. a-Methyl-quinaldin results from it by reduction. Water is 
 simultaneously liberated. 
 
 p-Amido-benzal-aeetone, m.p. 81, p-dimethyl-amido-benzal-acetone, 
 m.p. 132, by condensation of amido- and dimethyl-amido-benzalde- 
 hyde respectively with acetone. Its red and yellow chloride solutions 
 colour wool, silk, and tanned cotton an orange yellow (C. 1906, II. 1324). 
 
 a- and y-Benzylidene-methyl-ethyl-ketone C 6 H 5 CH : CHCOC 2 H 5 , 
 m.p. 39, b.p. 12 142, and C 6 H 5 CH : C(CH 3 )COCH 3 , m.p. 38, b.p. 12 
 i27-i3o, and a- and y-benzylidene-methyl-propyl-ketone C 6 H 5 CH : 
 
PHENYL-OLEFIN KETONES 417 
 
 CHCOC 3 H 7 , b.p. 20 155, and C 6 H 5 CH : C(C 2 H 5 )COCH 3 , b.p. 18 120- 
 130, with benzaldehyde and methyl-ethyl- and methyl-propyl-ketone 
 respectively, by means of NaHO and HC1 respectively. From benz- 
 aldehyde and phenoxy-acetone both NaHO and HC1 give : 
 
 a-Benzylidene-phenoxy-aeetone C 6 H 5 CH : C(OC 6 H 5 )COCH 3 , m.p. 
 102, which is reduced by alkaline hypochlorite to a-phenoxy-cinnamie 
 acid (B. 35, 3549). 
 
 Cuminal-acetone (A. 223, 147). Benzal-pinacolin C 6 H 5 CH : CH. 
 COC(CH 3 ) 3 , m.p. 41, b.p. 25 154, from benzaldehyde and pinacolin ; 
 it adds malonic acid ester with formation of 8, y-ketonic acid (B. 
 30, 2268). 
 
 Phenyl-vinyl-ketone C 6 H 5 COCH : CH 2 , b.p. 18 115, a colourless oil 
 of penetrating odour, formed by the action of alcoholic KI solution 
 upon a, jS-dibromo-propio-phenone, and by distillation of triphenacyl- 
 methyl-amino-chlorohydrate with steam (B. 39, 2187). It easily 
 polymerises in sunlight or on heating. A1C1 3 converts it into the iso- 
 meric a-hydrindone. With HC1, alcohol, and sodium bisulphite it 
 easily combines, with dissolution of the double linkage ; with phenyl- 
 hydrazin it forms i, 3-diphenyl-pyrazolin (C. 1910, I. 434). 
 
 Phenyl-propenyl-ketone C 6 H 5 COCH : CH.CH 3 , b.p. 20 135, is also 
 formed from crotonyl chloride, benzene, and A1C1 3 . 
 
 Allyl - aceto - phenone C 6 H 5 .CO.CH 2 .CH 2 .CH : CH 2 , from allyl- 
 benzoyl-acetic acid (B. 16, 2132), boils at 236. 
 
 46. Oxy-phenyl-olefin Ketones. o-Oxy-benzal-aeetone, methyl-o- 
 cumaro-ketone HO.C 6 H 4 .CH : CH.CO.CH 3 , m.p. 139, is obtained from 
 salicyl-aldehyde, and also by the action of emulsin upon gluco-methyl-o- 
 cumaro-ketone C 6 H n O 5 .O.C 6 H 4 .CH 4 : CH.COCH 3 , melting at 192. The 
 latter compound is a condensation product of helicin (q.v.) and acetone 
 (B. 24, 3180). p-Oxy-benzal-aeetone, m.p. 103, from p-oxy-benz- 
 aldehyde, acetone, and HC1, besides the p 2 -dioxy-dibenzal-acetone 
 occurring as a chief product (B. 36, 134) ; o-, m- and p-oxy-benzal- 
 acetone-o-acetic acid, m.p. 108, 122, and 177 (B. 19, 3056). Piper- 
 onylidene acetone CH 2 O 2 C 6 H 3 CH : CHCOCH 3 , m.p. 96 (B. 28, 
 R. 1009). 
 
 5. Phenyl-acetylene Aldehydes. Phenyl-propargyl aldehyde C 6 H 5 C 
 C.CHO, b.p. 2g 128, from sodium-phenyl-acetylide with formic acid in 
 ether (C. 1903, II. 569), or, better, from its acetal, easily obtained from 
 a-bromo-cinnamic-aldehyde-acetal, by treating it with dilute mineral 
 acids, is split up by aqueous alkalies, in the cold, into phenyl-acetylene 
 and formic acid. Its -oxime C 6 H 5 CC.CH : NOH, m.p. 108, is iso- 
 merised by aqueous alkali to phenyl-isoxazol, and by sodium ethylate 
 further to oj-cyanaceto-phenone C 6 H 5 CH 2 .CO.CN (B. 36, 3670). 
 
 6. Phenyl-acetylene Ketones are obtained synthetically from sodium- 
 phenyl-acetylide, with acid esters, chlorides, and anhydrides (C. 1900, 
 I. 1290; II. 1231; 1902, I. 404). Acetyl-phenyl-acetylene C 6 H 5 C 
 CCOCH 3 , b.p. 22 130, gives, with H 2 SO 4 , benzoyl-acetone, and is split 
 up by KHO into phenyl-acetylene and acetic acid. Butyryl-phenyl- 
 acetylene C 3 H 7 COC CC 6 H 5 , b.p. 9 136. Benzoyl-amyl-aeetylene C 6 H 5 
 COC : CC 5 H n , b.p. 19 178, from sodium-oenanthylidene with benzoyl 
 chloride, gives, with dilute sulphuric acid, benzoyl-caproyl-methane. 
 
 7. Phenyl - diolefin Ketones. Cinnamyl - acetone C 6 H 5 .CH : CH. 
 CH : CH.CO.CH 3 , m.p. 68, results from the condensation of cinnamic 
 
 VOL. II. 2 E 
 
4 i8 ORGANIC CHEMISTRY 
 
 aldehyde and acetone. Its oxime yields a pyridine derivative upon 
 dry distillation (B. 29, 613). Piperonylene-aeetone (CH 2 O 2 )C 6 H 3 .CH : 
 CH.CH : CH.CO.CHg, m.p. 89 (B. 28, 1193). Benzal-mesityl oxide 
 C G H 6 .CH : CH.CO.CH : C(CH 3 ) 2 , b.p. 178 (14 mm.) (B. 14, 351). 
 Piperonylene-aeetone (CH 2 O 2 )C 6 H 3 .CH : CH.CH : CH.CO.CH 3 melts at 
 89 (B. 28, 1193). 
 
 8. Phenyl-olefin-carboxylie Acids. These acids arrange themselves 
 in two distinct classes. The one class is derived from a saturated acid, 
 by substituting an unsaturated side chain for hydrogen attached to 
 the benzene nucleus e.g. vinyl-benzoic acid. The second class com- 
 prises the phenylated olefin-monocarboxylic acids. 
 
 A. Phenyl-olefin-carboxylie acids (having their CO 2 H group attached 
 to the nucleus). 
 
 o- Vinyl-benzoic acid CH 2 : CH[2[C 6 H 4 .CO 2 H. o- Vinyl-benzoic acids, 
 chlorinated in the vinyl residue, and also in the benzene residue, have 
 been obtained by the decomposition of chlorinated hydrindene and 
 naphtho-quinone derivatives (B. 27, 2761 ; A. 275, 347). 
 
 m- Vinyl-benzoic acid, m.p. 95, is formed from m-amido-styrol 
 (B. 26, R. 677). o-, m-, and p-Propenyl-benzoic acids CH 2 : C(CH 3 ). 
 C 6 H 4 .CO 2 H, m.p. 60, 99, and 161 (A. 219, 270 ; 248, 64 ; 275, 160). 
 
 o-Vinyl-phenyl-acetic acid CH 2 : CH.C 6 H 4 .CH 2 .CO 2 H. Derivatives 
 of this acid, chlorinated in the vinyl residue, have also been obtained 
 by the breaking down of chlorinated keto-hydro-naphthalenes (B. 
 
 21, 3555). 
 
 B. Phenyl-olefin-carboxylie acids (with the carboxyl group in the 
 unsaturated aliphatic side chain). 
 
 The true phenyl-olefm-monocarboxylic acids may be obtained by 
 the oxidation of corresponding alcohols and aldehydes, as well as, by 
 similar methods, from the phenyl-paramn-monocarboxylic acids or 
 fatty acids. The nuclear-synthetic method, however, is far more 
 important. It consists in the action of the sodium salt, and the 
 anhydride of a fatty acid, upon an aromatic aldehyde (Perkin's reaction). 
 
 History. As early as the year 1856 Bertagnini found that cinnamic 
 acid was formed upon heating benzaldehyde with acetyl chloride. 
 In 1865 W. H. Perkin, sen., synthesised cumarin, the lactone of 
 o-oxy-cinnamic acid, by heating sodium salicyl-aldehyde with acetic 
 anhydride. In 1875 Perkin gave this reaction an entirely different 
 aspect by allowing sodium acetate and acetic anhydride to act upon 
 salicyl-aldehyde. In this modified form the reaction acquired more 
 general application. 
 
 Many chemists have assisted in the amplification of the Perkin 
 reaction, which in consequence has become one of the most fruitful 
 synthetic methods. 
 
 The course of the reaction has been made clear by the researches 
 of v. Baeyer and O. R. Jackson, Conrad and Bischoff, Oglialoro, and 
 especially by those of Fittig and his students, Jayne and Slocum 
 (A. 215, 97, 116 ; 227, 48) : 
 
 (1) In the condensation of aromatic aldehydes and fatty acids the 
 carbon atom, combined with the carboxyl group, unites with the carbon 
 of the aldehyde group. 
 
 (2) It is doubtful whether the reaction takes place between the 
 aldehyde and the Na salt, or the anhydride of the fatty acid, since, 
 
PHENYL-OLEFIN-CARBOXYLIC ACIDS 419 
 
 on using a mixture of anhydride and Na salt of two different acids, 
 we obtain various mixtures of the two possible phenyl-olefin-carboxylic 
 acids, according to circumstances ; cp. B. 34, 918. 
 
 (3) The condensation proceeds in two stages : (a) the union of the 
 aldehyde and the sodium salt, as in the formation of aldol, with the 
 production of the /?-oxy-acid ; (b) the exit of water from the j3-oxy- 
 acid, resulting in the formation of the olefin-carboxylic acid. In 
 many instances the reaction was arrested in the first stage : 
 
 (a) C 6 H 5 .CHO+CH 3 .C0 2 H - -> C 6 H 5 .CH(OH).CH 2 .CO 2 H. 
 
 (b) C 6 H 5 .CH(OH)CH 2 .CO 2 H- ::5 ^-> C 6 H 5 .CH : CH.CO 2 H. 
 
 A second nucleus-synthetic method for the preparation of phenyl- 
 olefin-carboxylic acids consists in the condensation of benzaldehydes 
 with fatty-acid esters by means of sodium ethylate or metallic sodium 
 (Claisen, B. 23, 976) : 
 
 C 6 H 5 .CHO+CH 3 .CO.O.C 2 H 5 -^^ > C 6 H 5 .CH : CH.CO 2 .C 2 H 5 . 
 
 Phenyl-acrylic Acids. According to the structural theory there 
 are two possible isomerides, the a- and j8-acids, which are also known 
 in cinnamic and atropic acids : 
 
 /5-Phenyl-acrylic acid, r ru rw rn w a- Phenyl-acrylic acid, r r 
 
 cinnamic acid, C.H..CH : CH.CO,H atropic acid, * s \ C H 
 
 Cinnamic acid, f$-phenyl-acrylic acid, acidum cinnamylicum C 6 H 5 . 
 CH : CH.CO 2 H, melting at 133 and boiling at 300, occurs in Peru 
 and tolu balsams, in storax, and in some benzoin resins ; also, together 
 with a- and jS-truxillic acids, the natural iso-cinnamic and allo-cinnamic 
 acids, in the decomposition products of the associated alkaloids of 
 cocain. 
 
 Formation. It is produced (i) by the oxidation of its alcohol and 
 its aldehyde ; (2) by the reduction of phenyl-propiolic acid with zinc 
 dust and glacial acetic acid (B. 22, 1181) ; (3) nuclear synthesis from 
 benzaldehyde : (a) with sodium acetate and acetic anhydride, (b) with 
 acetic ester and sodium ethylate (see above) ; (4) upon heating benzyl 
 chloride with sodium acetate. The latter reaction serves for the 
 commercial preparation of cinnamic acid (B. 15, 969) ; (5) by heating 
 benzal-malonic acid ; (6) its phenyl ester is produced when phenyl- 
 fumaric ester is heated ; (7) by splitting off water from synthetic 
 j8-phenyl-hydracrylic acid. 
 
 Properties and Behaviour. Cinnamic acid crystallises from hot 
 water in fine needles, from alcohol in thick prisms. It is soluble in 
 3500 parts of water at 17, and readily in hot water. It may be purified 
 by distillation under greatly reduced pressure, or by crystallisation 
 from petroleum benzin (A. 188, 194). 
 
 Ferric chloride produces a yellow precipitate in solutions of the 
 cinnamates. 
 
 Nitric acid and chromic acid oxidise it to benzaldehyde and benzoic 
 acid. It is converted into phenyl-glyceric acid by potassium perman- 
 ganate. Fusion with caustic potash decomposes it into benzoic and 
 acetic acids. 
 
 Being an unsaturated acid, cinnamic acid can readily take up 
 hydrogen, hydrogen bromide, hydrogen iodide, bromine, chlorine, and 
 
420 ORGANIC CHEMISTRY 
 
 hypochlorous acid, with the .production of hydro-cinnamic acid, 
 jS-bromo-, /?-iodo-hydro-cinnamic acid, phenyl-a, j3-dichloro-, a, jS-di- 
 bromo-propionic acid, or cinnamic acid dichloride, cinnamic acid 
 dibromide, and j3-phenyl-a-chloro-lactic acid. 
 
 Cinnamic Acid Derivatives. Methyl ester melts at 33 and boils at 
 263. It is contained in some Alpinia varieties. Ethyl ester boils at 
 271. Phenyl ester melts at 72 and boils at 206 (15 mm.) ; see Cin- 
 namic acid. Pyro-cateehol ester melts at 129 (B. 11, 1220 ; 18, 1945 ; 
 25, 3533). Benzyl ester, m.p. 30, also found in the oil of Peruvian 
 balsam (B. 2, 180). 
 
 Styryl ester, stymcin, melts at 14. The chloride melts at 35 and 
 boils at 154 (25 mm.). The anhydride melts at 130 (B. 27, 284). 
 The amide melts at 141. The anilide melts at 151. The nitrile melts 
 at 11 and boils at 254 (B. 15, 2544 ; 27, R. 262). 
 
 Unstable and Polymeric Modifications of Cinnamic A cid. As in the 
 jS-alkyl-acrylic acids (Vol. I.), so also in the j3-phenyl-acrylic acids, 
 besides the ordinary stable forms, the corresponding unstable stereo- 
 isomeric forms have been discovered, and have been termed " allo- 
 cinnamic " acids. Allo-cinnamic acid itself has the noteworthy pro- 
 perty of being able to occur in three crystalline forms which are chemi- 
 cally identical but structurally different. These can be converted 
 into one another by the simple process of melting or crystallisation 
 (Biilmann, B. 42, 182, 1443). 
 
 The modification, m.p. 42, formerly called Erlenmeyer's iso-cin- 
 namic acid, is the most unstable, much more so than the modification 
 melting at 58 (formerly Liebermann's iso-cinnamic acid), and the modi- 
 fication melting at 168 (formerly Liebermann's allo-cinnamic acid). 
 
 But it is the acid which, with certain precautions, can always be 
 obtained from the mixture of the three liquid acids, or of the three 
 acids, in solution, on precipitation with acid (B. 42, 4659 ; 43, 411). 
 In all reactions which give rise to allo-cinnamic acid it is the primary 
 product, but it is extremely easily transformed into the other acids, 
 especially the stable acid melting at 68, on contact with the slightest 
 traces of crystals of the other acids. Allo-cinnamic acid is obtained 
 in one or other of its three forms (i) by semi-reduction of phenyl- 
 propiolic acid with hydrogen and colloidal palladium (B. 42, 3930) ; 
 (2) by reduction of allo-a- and allo-jS-bromo-cinnamic acid with zinc 
 dust in an alcoholic solution ; (3) by the action of ultra-violet light 
 upon an alcoholic solution of ordinary cinnamic acid (B. 42, 4869) ; (4) 
 by heating benzal-malonic acid, whereby also much ordinary cinnamic 
 acid is formed. 
 
 The acid melting at 58 was first discovered in the acids resulting 
 from the breaking up of the secondary cocai'n alkaloids, together with 
 ordinary cinnamic acid. 
 
 Allo-cinnamic acid, m.p. 68, forms an aniline salt, m.p. 83, 
 sparsely soluble in ligroin. With chlorine and bromine it yields 
 addition products differing from cinnamic dichloride and allo-cinnamic 
 acid dibromide. 
 
 On distillation at ordinary pressure by concentrated sulphuric acid 
 and by illumination in benzene solution with the addition of a little 
 iodine, allo-cinnamic acid is converted into ordinary cinnamic acid 
 (B. 28, 1446). On oxidation with potassium permanganate it forms 
 
PHENYL-OLEFIN-CARBOXYLIC ACIDS 421 
 
 phenyl-glycerine acid melting at 21. On treating with fuming 
 sulphuric acid it splits off water and easily polymerises into tmxone, 
 in contrast with ordinary cinnamic acid (B. 31, 2095). On account of 
 this behaviour, but especially of their generation from phenyl-propiolic 
 acid and jS-bromallo-cinnamic acid respectively, allo-cinnamic acid is 
 regarded as the maleinoid or cis-form, and ordinary cinnamic acid as 
 the fumaroid or trans-iorm, of j8-phenyl-acrylic acid : 
 
 H C C 6 H 5 H C CH 5 
 
 HOoC C H H C CO 2 H 
 
 Ordinary cinnamic acid Allo-cinnamic acid. 
 
 This view agrees with the behaviour of the oxy-cinnamic acids, 
 in which the spatial configuration can be deduced from the more or 
 less marked tendency towards splitting off H 2 O. It is also confirmed 
 by the power of allo-cinnamic acid, in contrast with cinnamic acid, 
 to form with mercuric salts an additive compound of the formula 
 
 C<}H 5 CH(OH)CHHg.COO, a power which, according to observations 
 with other cis-trans-isomeric olefin-dicarboxylic acids, can only be 
 ascribed to the maleinoid forms (B. 43, 568). 
 
 By the action of light, in the solid condition cinnamic acid is poly- 
 merised into the so-called a-truxillie acid (C 6 H5C 2 H 2 COOH) 2 (B. 35, 
 2908, 4128), also found in the secondary alkaloids of cocai'n together 
 with jS, y, and 8-truxillic acid. On distillation these acids are split up 
 into ordinary cinnamic acids. They are, perhaps, diphenyl-tetra- 
 methylene-dicarboxylic acids. As the heat of combustion is unchanged, 
 the transformation of cinnamic into truxillic acid involves no change 
 of energy, which is noteworthy (Z. physik. Ch. 48, 345). 
 
 Haloid Cinnamic Acids substituted in the Side Chain. (a) Phenyl- 
 monohaloid-aerylic Acids. The structural theory provides for two 
 isomeric monochloro-acrylic acids, but there are really two modifica- 
 tions for each of these structural isomerides. It is customary to dis- 
 tinguish them as a- and j8-chloro-cinnamic acid and allo-a- and allo- 
 j3-chloro-cinnamic acid (B. 22, R. 741 ; A. 287, i). 
 
 a-ChlcTO-eiimamie acid C 6 H 5 .CH : CC1.CO 2 H, m.p. 137, is formed 
 (i) by the action of alcoholic potash or phenyl-a-, j3-dichloro-propionic 
 acid ; (2) from benzaldehyde, sodium monochloro-acetate, and acetic 
 anhydride ; (3) from phenyl-a-chloro-lactic acid, by means of acetic 
 anhydride, and sodium acetate ; (4) by the action of CrO 3 upon aldehyde 
 (B. 24, 249). 
 
 Allo-a-chloro-cinnamic acid, m.p. 111, is produced, together with 
 a-chloro-cinnamic acid, according to method i. 
 
 /3-Chloro-cinnamie acid C 6 H 5 .CC1 : CH.CO 2 H, m.p. 132-5, and 
 allo-^-ehloro-cinnamic acid, m.p. 142, are formed by the addition of 
 hydrochloric acid to phenyl-propionic acid. 
 
 a-Bromo-einnamie acid, C 6 H 5 .CH : CBr.CO 2 H, m.p. 130, and 
 allo-a-bromo-ciimamic acid, m.p. 120 (Glaser's jS-bromo-cinnamic 
 acid), result when phenyl-a, /3-dibromo-propionic acid is acted upon 
 with alcoholic potash. The latter, when heated, changes to the higher- 
 melting a-bromo-cinnamic acid. When it is treated with zinc dust 
 in alcoholic solution it yields allo-cinnamic acid. Both yield benz- 
 aldehyde upon oxidation. 
 
422 ORGANIC CHEMISTRY 
 
 j8-Bromo-cinnamic acid C 6 H 5 .CBr : CH.CO 2 H, m.p. 133, and allo- 
 j8-bromo-cmnamie acid, m.p. 158-5, are formed simultaneously upon 
 the addition of hydrogen bromide to phenyl-propiolic acid. The 
 second acid, upon heating, changes to the lower-melting j8-bromo- 
 cinnamic acid, and upon reduction yields not only cinnamic acid, 
 but also allo-cinnamic acid. 
 
 jS-Iodo-cinnamic acid CeH 6 CI : CHCOOH is obtained by iodina- 
 tion of cinnamic acid in pyridin solution (C. 1899, II. 527). 
 
 (b) Phenyl-dihaloid-acrylic acids result from the addition of halogens 
 to phenyl-propiolic acid. Dichloro-einnamic acid C 6 H 5 .CC1 : CC1.CO 2 H, 
 m.p. 120 (B. 25, 2665). a- and /3-Dibromo-cinnamie acids melt at 
 139 and 100 (B. 25, 2665). Di-iodo-cinnamie acid melts at 121 
 (B. 24, 4113). 
 
 a-Amido-cinnamic acid C 6 H 5 .CH : C(NH 2 ).CO 2 H decomposes, when 
 rapidly heated, at 24O-25o, with the production of phenyl-vinyl- 
 amine. Its hydrochloride is produced upon heating its benzoyl-amido- 
 cinnamic anhydride with hydrochloric acid to 120. The acid itself 
 may be liberated from the hydrochloride by means of sodium acetate 
 or soda. The amide of an isomeric (?) a-amido-cinnamic acid, m.p. 160, 
 is formed by the action of ammonia upon phenyl-dibromo-propionic 
 ester or a-bromo-cinnamic ester (B. 29, R. 795). 
 
 a-Acetamido-cinnamic acid C 6 H 5 .CH : C(NHCO.CH 3 ).CO 2 H+2H 2 O 
 melts, when anhydrous, at 190 with decomposition. It is formed 
 when sodium hydroxide acts upon the anhydride. 
 
 CO O 
 
 a-Aeetamido-einnamic anhydride , melting at 
 
 C 6 H 5 CH : C.N : CCH 3 
 
 146, results from the action of acetic anhydride upon a-amido- 
 phenyl-lactic acid, and from glycocoll, benzaldehyde, sodium acetate, 
 and acetic anhydride. 
 
 a-Benzoyl-amido-cinnamic anhydride melts at 165. It is produced 
 in the condensation of hippuric acid and benzaldehyde with acetic 
 anhydride and sodium acetate. When heated with dilute alkalies 
 the lactimide changes to a-benzoyl-amido-cinnamic acid C 6 H 5 CH : 
 C(NHCOC 6 H 5 )COOH, which decomposes at 275 with the formation of 
 phenyl-acetaldehyde and is split up by excess of alkali into benzamide 
 and phenyl-racemic acid (B. 33, 2036). p-Oxy-benzoyl-amido-cinnamie 
 acid anhydride, m.p. 173, from p-oxy-benzaldehyde, hippuric acid ; 
 the corresponding acid is reduced by sodium amalgam to benzoyl- 
 ty rosin. 
 
 Cinnamic acids substituted in the benzene nucleus are isomeric with 
 the corresponding mono-cinnamic acid derivatives, having side-chain 
 substitutions. 
 
 1. Mono-haloid Cinnamic Acids have been made from the three 
 nitro-cinnamic acids as bases (B. 16, 2040 ; 18, 961 ; 25, 2109). 
 
 o-, m-, and p-Chloro-cinnamic acids melt at 200, 176, and 241. 
 
 o- and m-Bromo-cinnamic acids melt at 212 and 178. 
 
 o-, m-, and p-Iodo-cinnamic acids melt at 213, 181, and 255. 
 
 2. Nitro-cinnamic Acids. The introduction of cinnamic acid into 
 nitric acid of specific gravity 1-5 leads to the formation of the ortho- 
 (60 per cent.) and para-nitro-acids. To separate them, cover the acid 
 mixture with 8-10 parts of absolute alcohol, and conduct hydrochloric 
 
PHENYL-OLEFIN-CARBOXYLIC ACIDS 423 
 
 acid gas rapidly into the liquid, until complete solution ensues. On 
 cooling, the para-ester separates. The pure esters are saponified with 
 sodium carbonate or with dilute sulphuric acid, when the pure acids 
 result (A. 212, 122, 150 ; 221, 265). 
 
 The three isomeric acids can be prepared from the corresponding 
 nitro-benzaldehydes by means of Per kin's reaction : 
 
 o-, m-, and p-Nitro-cinnamic acids, m.p. 240, 197, 286. 
 o-, m-, and p-Nitro-cinnamic ethyl esters, m.p. 44, 78, 138. 
 
 Oxidation converts the three nitro-cinnamic acids into the three 
 nitro-benzaldehydes and nitro-benzoic acids. 
 
 Further nitration of o-, m-, and p-nitro-cinnamic acids produces 
 dinitro-cinnamic acids, containing an NO 2 group in the side chain ; 
 o, p-dinitro-cinnamic acid (NO 2 )[2, 4]C 6 H 3 CH : CHCOOH, m.p. 179, 
 is obtained from o, p-dinitro-benzaldehyde by means of Perkin's 
 reaction (M. 23, 534). m- and p-nitro-cinnamic acids are decomposed 
 at 230 and 220 respectively (C. 1904, II. 1498). 
 
 Cinnamic Acids substituted, both in the Benzene Residue and the Side 
 Chain, a, m-Dinitro-einnamie acid NO 2 [3]C 6 H 4 .CH : C(NO 2 )COOH, 
 from m-nitro-cinnamic acid ester, with nitro-sulphuric acid (A. 229, 
 224). a, p-dinitro-cinnamic acid, p-nitro-phenyl-a-nitro-acrylic acid, 
 from p-nitro-cinnamic acid (A. 229, 224). See also a), p-Dinitro-phenyl- 
 ethylene and p-Amido-phenyl-alanin. a- and /J-Nitro-o-amido-cin- 
 namic acid, m.p. 240 and 254, from o-amido-cinnamic acid. 
 
 3. Amido-cinnamic Acids can be prepared by reducing the three 
 mononitro-cinnamic acids with tin and hydrochloric acid. The re- 
 duction is better effected with ferrous sulphate in an alkaline solution 
 (B. 15,2294; A. 221,266). 
 
 o-, m-, and p-Amido-cinnamic acids melt at 158, 181, and 176. 
 When the diazo-bodies are boiled with haloid acids, the haloid cinnamic 
 acids, described above, are produced ; but when they are acted upon 
 with boiling water, the products are o-, m-, and p-cumaric acids. 
 
 Carbostyril Formation. Free o-amido-cinnamic acid differs from 
 o-amido-hydro-cinnamic acid in behaviour, in that, when heated alone, 
 it does not give rise to an inner anhydride formation ; it behaves like 
 o-cumaric acid. The anhydride formation occurs, however, when 
 o-amido-cinnamic acid is heated with hydrochloric acid (B. 13, 2070), 
 or with 50 per cent, sulphuric acid (B. 18, 2395). The resulting an- 
 hydride is carbostyril, discovered in 1852 by Chiozza, when he reduced 
 o-nitro-cinnamic acid with ammonium sulphide. It can be viewed 
 both as a lactime and a lactame : 
 
 Lactame formula. C.H.{gJ : Lactime formula, C.H 4 {W^H : 
 
 According to the second formula, carbostyril is nothing more than 
 a-oxy-quinolin ; hence it will be discussed later, in conjunction with 
 quinolin. This will also be done with the alkyl compounds derived 
 from both formulae. 
 
 o-Ethyl-amido-cinnamic acid, m.p. 125 (B. 15, 1423). Its nitros- 
 amine melts at 150 with decomposition, and, on reduction, is con- 
 densed to ethyl-isindazol-acetic acid. 
 
 4. o-Hydrazin-cinnamic acid NH 2 .NH.C 6 H 4 .CH : CH.CO 2 H, m.p. 
 
424 ORGANIC CHEMISTRY 
 
 /CH.NH 
 171 with decomposition into indazol C 6 H 4 <J (q.v.), and acetic 
 
 .w 
 acid. 
 
 o - Sulpho - hydrazin - cinnamic acid SO 3 H.NH.NH.C 6 H 4 CH : 
 CH.CO 2 H is formed when sodium sulphite acts upon the hydro- 
 chloride of o-diazo-cinnamic acid. Hot hydrochloric acid breaks 
 it down into o-hydrazin-cinnamie acid and the lactame of this acid 
 
 ^{SSS^ 00 ' m ' p - 127 (A " 221 ' 274) ' 
 
 5. Sulpho-cinnamic Acids are produced when fuming sulphuric acid 
 acts upon cinnamic acid (A. 173, 8). The m-derivative has been ob- 
 tained by a nuclear synthesis from m-benzaldehyde-sulphonic acid. 
 p-Sulpho-cinnami'c acid, on reduction, splits off the sulpho-groups, 
 and produces hydro-cinnamic acid (B. 33, 2014 ; C. 1903, II. 438). 
 
 Homologous Cinnamic Acids. Cinnamic acids containing alkyl 
 groups in the benzene residue are produced when alkylated benzalde- 
 hydes are condensed with sodium acetate and acetic anhydride. The 
 three tolyl-aldehydes yield o-, m-, and p-methyl-cinnamic acids, j8, o-, 
 m-, and p-tolyl-acrylic acids, melting at 169, 115, and 196. Cuminol 
 yields p-cumenyl-acrylic acid (CH 3 ) 2 CH[4]C 6 H 4 .CH : CH.CO 2 H, melting 
 at 158. When the latter is nitrated it yields not only the p-nitro-acid, 
 but also o-nitro-cumenyl-acrylic acid, which manifests the same re- 
 action transpositions as o-nitro-cinnamie acid (B. 19, 255). 
 
 a- Alky I substituted cinnamic acids are produced in the condensation 
 of benzaldehyde with sodium propionate, capronate, or butyrate and 
 acetic anhydride (A. 227, 57 ; B. 34, 918). 
 
 a-Methyl - cinnamic acid, a-benzal-propionic acid, p-phenyl- 
 methacrylic acid C 6 H 5 .CH : C(CH 3 )CO 2 H, melting at 78 and boiling 
 at 288, is also formed from benzyl-propionic ester and metallic sodium 
 (B. 20, 617). Also from a-methyl-jS-phenyl-ethylene-lactic acid by 
 splitting off water (C. 1898, I. 674 ; B. 20, 617). 
 
 Phenyl-angelica acid, a-ethyl-cinnamic acid, a-benzal-n-bntyric acid 
 C 6 H 5 .CH : C(C 2 H 5 )CO 2 H melts at 104 (B. 23, 978). 
 
 j8-Alkyl-substituted cinnamic acids are obtained by detaching H 2 O 
 from )3-aryl-alkyl-hydracrylic acids, the condensation products of aro- 
 matic ketones with bromacetic ester,, and zinc, or iodo-acetic ester, 
 and magnesium, respectively (B. 40, 1589 ; 41, 5). 
 
 j8-Methyl-cinnamie acid, j3-phenyl-erotonic acid C 6 H 5 C(CH 3 ) : 
 CHCOOH, m.p. 98, b.p. 167 ; anilide, from dypnone oxime by Beck- 
 mann's transformation (B. 37, 733). j8-Ethyl-, j8-n-propyl-, and /Mso- 
 butyl-einnamic acids melt at 95, 94, and 86 respectively. 
 
 Higher cD-phenyl-n-olejin-carboxylic acids are produced by heating 
 the lactone-carboxylic acids, when carbon dioxide is expelled, and 
 in the reduction of phenyl-diolefin-dicarboxylic acids. 
 
 Phenyl-iso-crotonic acid, p-benzal-propionic acid C 6 H 5 .CH : CH. 
 CH 2 .CO 2 H melts at 86 and boils at 302 with partial decomposition 
 into water and a-naphthol. It is formed also by expelling CO 2 and 
 rearranging phenyl-paraconic acid, as well as from phenyl-trimethylene- 
 
 / P M f** O O "H" 
 
 tricarboxylic acid C 6 H 5 C(COOH)Q^* (B. 25, 1155), by heat- 
 ing*; also by heating phenyl-acetaldehyde, malonic acid, and pyridin 
 from the benzal-malonic acid first formed by detaching CO 2 , and dis- 
 
PHENYL-OLEFIN-CARBOXYLIC ACIDS 425 
 
 placing the double linking (A. 345, 244). With HBr it combines to 
 y-phenyl-y-bromo-butyric acid, which, with soda solution, forms 
 phenyl-butyro-lactone, into which phenyl-iso-crotonic acid can also 
 be partly converted, by means of dilute sulphuric acid or HC1 ; 
 concentrated HC1 condenses phenyl-iso-crotonic acid to a polymeric 
 unibasic lactonic acid, melting at 179 (B. 23, 3520). 
 
 a- and /?-Methyl-phenyl-iso-crotonic acids melt at 110 and 112 
 (A. 255, 262). A 2 -Dihydro-cinnamenyl-acrylic acid C 6 H 5 .CH 2 .CH : 
 CH.CH 2 .CO 2 H, melting at 31, is formed when sodium amalgam acts 
 upon cinnamenyl-acrylic acid, and also by heating A 2 - and A a -cinna- 
 mylidene-malonic acid. a-Benzyl-erotonie acid C 6 H 5 CH 2 C( : CH.CH 3 ) 
 COOH, m.p. 99, by detaching water from a-benzyl-/?-oxy-butyric acid. 
 
 The behaviour of these phenyl-olefin-carboxylic acids towards 
 alkalies is worthy of note. While the aliphatic /?, y-unsaturated acids 
 are transposed by alkalies into the isomeric a, jS-unsaturated acids 
 (Vol. I.), the aromatic olefin-car boxy lie acids show, at the same time, 
 a tendency to place the double linking in the neighbourhood of the 
 phenyl group (cp. A 2 - and A 1 -styrols). Thus, the A 2 -dihydro-cinna- 
 menyl-acrylic acid, with caustic soda, gives a mixture of the A 1 - and 
 A 3 -acids (B. 38, 2742). Phenyl-crotonic acid, on mere heating with 
 pyridin, passes, almost completely, into the phenyl-iso-crotonic acid, 
 a reaction which can be partly reversed by boiling with caustic soda 
 (A. 283, 309). a-Benzyl-crotbnic acid gives, on fusing with KHO, 
 phenyl-angelica acid (/. pr. Ch. 2, 74, 334 ; cp. also A. 319, 144). 
 
 C 6 H 5 CH : CH.CH 2 .CH 2 .CO 2 H - C,H 5 CH 2 .CH : CH.CH 2 CO 2 H v 
 
 A 3 -acid, m.p. 90 A 2 -Dihydro-cinnamenyl-acrylic acid 
 
 C G H 5 CH 2 .CH 2 CH : CHCO 2 H 
 A 1 -acid, m.p. 104. 
 
 C 8 H 5 CH : CH.CH 2 .COOH < x C 6 H 5 CH 2 CH : CH.COOH 
 
 Phenyl-iso-crotonic acid, m.p. 86 Phenyl-crotonic acid, m.p. 65. 
 
 C 6 H 5 CH 2 C( : CHCH 3 )COOH - -^ C 6 H 5 CH : C(CH 2 .CH 3 )COOH 
 a-Benzyl-crotonic acid, m.p. 99 Phenyl-angelica acid, m.p. 105. 
 
 The A 3 -dihydro-cinnamenyl-acrylic acid has also been obtained by 
 distillation of 8~phenyl-S-valero-lactone-y-carboxylic acid. 
 
 Atropie acid, a-phenyl-acrylic acid c 6 H 5 .c^ 2H melts at 106. 
 
 This acid, structurally isomeric with ordinary cinnamic acid, results 
 from tropic acid and atro-lactinic acid when they are heated with 
 concentrated hydrochloric acid or with baryta water. It is sparingly 
 soluble in cold water, easily in ether, carbon disulphide, and benzene, 
 and distils with aqueous vapour. Chromic acid oxidises it to benzoic 
 acid ; when fused with caustic alkali it yields formic and a-toluic acids ; 
 sodium amalgam converts it into hydrb-atropic acid, and hydrochloric 
 and hydrobromic acids change it to a- and /Mialogen hydro-atropic 
 acids. 
 
 Protracted fusion, or heating with water or hydrochloric acid, con- 
 verts atropic acid into two polymeric isatropic acids, diatropic acids 
 (C 9 H 8 O 2 ) 2 (melting at 237 and 206), which bear the same relation to 
 atropic acid that the truxillic acids sustain to cinnamic acid (B. 28, 137). 
 
426 ORGANIC CHEMISTRY 
 
 Methyl-atropie acid C 6 H 5 .C\ 3 , m.p. 135, is obtained from 
 
 phenyl-acetic acid and paraldehyde by the action of acetic an- 
 hydride (B. 19, R. 251). 
 
 Phenyl-allyl-acetic acid C 6 H 5 .CH(CH a .CH : CH 2 )COOH, b.p. 200, 
 has been obtained from phenyl-allyl-malonic acid, and its nitrite from 
 benzyl cyanide, allyl iodide, and caustic soda (B. 29, 2601). 
 
 Illb. OXY-PHENYL-OLEFIN-CARBOXYLIC ACIDS. 
 
 A. Monoxy-phenyl-olefln-carboxylie Acids. Formation : They are 
 obtained (i) from the corresponding amido-phenyl-olenn-carboxylic 
 acids upon boiling the diazo-compounds with water (B. 14, 479) ; 
 (2) by a nuclear synthesis, when the phenol-aldehydes are heated 
 with the sodium salts, and anhydrides, of the fatty acids (Perkin's 
 reaction) . 
 
 The following nuclear syntheses (von Pechmann) lead to the inner 
 anhydrides or S-lactones of the o-oxy-cinnamic acids, the so-called 
 cumarins : (3) The action of sulphuric acid upon phenol and malic acid, 
 when it is very probable that the first product is the semi-aldehyde of 
 malonic acid, which condenses with the phenol. 
 
 (4) When sulphuric acid is allowed to act upon phenol, and aceto- 
 acetic ester, or monoalkyl-aceto-acetic esters. 
 
 Phenol itself, with aceto-acetic ester, gives but a small yield of 
 methyl-cumarin. Polyvalent phenols give cleaner reactions in this 
 respect than simple phenols, and the best are those containing two OH- 
 groups : 
 
 , r K /H+C0 2 H.CH(OH).CH, PM /[i]CH:CH r 
 
 C * H * \OH ' ' ' HOCO"" ' * o Co 
 
 H+CH 3 .CO.CH 2 _ r /[i]C(CH 3 ) : CH tf-Methyl- 
 C 2 H 6 0:CO C6H4 l[2]0 __ CO cumarin. 
 
 The first members of this series are the monoxy-cinnamic acids 
 obtained by method I from the three amido-cirmamic acids. o-Oxy- 
 cinnamic acids are especially important. They, like the cinnamic 
 acids, occur in two stereo-isomeric forms : o-cumaric acids, correspond- 
 ing to the stable trans-ioTm ; and cumarinic acids, corresponding to 
 the unstable a's-form. The cumarinic acids are in general unstable 
 in the free state, spontaneously detaching water, and passing into the 
 corresponding 8-lactones, the so-called " cumarins." But salts and 
 ethers, both mono- and dialkyl ethers, of the cumarinic acids, are 
 known, which are isomeric with the corresponding compounds of the 
 o-cumaric acids. 
 
 The salts and ethers of cumarin are also designated as a-cumarates, 
 and those of o-cumaric acid as the j8-cumarates salts and ethers. 
 
 When the hydrogen atom in cumarin, occupying the o-position 
 with reference to phenol-oxygen, is replaced by the nitro-group, free 
 nitro-cumarinic acid may be liberated from the salts. 
 
 This acid is distinguished from free 3-nitro-cumaric acid in that 
 by the exit of water it reverts to 3-nitro-cumarin. In order to 
 account for the different removability of water in o-cumaric acid and 
 
MONOXY-PHENYL-OLEFIN-CARBOXYLIC ACIDS 427 
 
 cumarinic acid respectively, the following space formulae have been 
 
 proposed : 
 
 HC.COOH THC.COOH 1 ^ HC CO 
 
 HOC 6 H 4 .CH LHC.C 6 H 4 OHJ * HC.C a H 4 6 
 
 o-Cumaric acid Cumarinic acid Cumariii. 
 
 As in the case of cinnamic acid, the stable o-cumaric acids 
 and their derivatives may easily be transformed into the unstable 
 cumarinic acids by means of ultra-violet light, i.e. by supplying 
 energy in a suitable form. In this action o-cumaric acid yields 
 cumarin direct (B. 44, 637). By boiling with dilute mineral acids, 
 or by the action of iodine in CS 2 solution, the o-alkyl-cumarinic acids 
 can be transposed into the more infusible o-alkyl-cumaric acids 
 C. (1907, I. 636). 
 
 By the action of light in the solid state the o-cumaric acids are 
 transformed into bimolecular bis-cumaric acids, corresponding to the 
 truxillic acids (B. 37, 1383). 
 
 o-Oxy-cinnamic acid, o-cumaric acid HO[2]C 6 H4<:H : CH.CO 2 H, 
 melting at 208, and isomeric with hydro-cumarilic acid, phenyl-pyro- 
 racemic acid, etc., occurs in Melilotusofficinalis, together with o-hydro- 
 cumaric acid, and in the leaves of Angrcecum fragrans. Nitrous acid 
 converts o-amido-cinnamic acid into cumaric acid. It is most readily 
 prepared by boiling cumarin for some time with concentrated potassium 
 hydroxide, or, better, with sodium ethylate (B. 18, R. 28 ; 22, 1714). 
 Its acetyl derivative is obtained from salicylic aldehyde and sodium 
 acetate. 
 
 Ortho-cumaric acid is very easily soluble in hot water and in alcohol. 
 It does not volatilise with steam. The free cumaric acid heated alone 
 does not yield cumarin, but only when treated with acetic chloride or 
 anhydride. Sodium amalgam converts it into melilotic acid, and fusion 
 with potassium hydroxide into salicylic and acetic acids. 
 
 2 -Methoxy- cinnamic acid (0) CH 3 O[2]C 6 H 4 [i]CH : CH.CO 2 H, 
 melting at 182, is produced by the action of sodium acetate and acetic 
 anhydride upon salicyl-aldehyde-methyl ether, and by the rearrange- 
 ment of methyl-cumarinic acid. Sodium amalgam reduces it to 
 melilotic acid methyl ether, while bromine changes it to methyl-ether- 
 dibromo-melilotic acid. o-Cumaric dimethyl ether (jB) CH 3 O[2]C 6 H 4 
 [i]CH : CH.CO 2 CH 3 , boiling at 293, is obtained from the previously 
 described acid chloride by means of methyl alcohol. Aeeto-o-eumaric 
 acid CH 3 .CO.O[2]C 6 H 4 .CH : CH.CO 2 H, m.p. 149, is obtained from 
 salicyl-aldehyde, acetic anhydride, and sodium acetate (B. 20, 284). 
 See Cumarin. 
 
 3-Nitro-cumaric acid (j8) NO 2 [3]C 6 H 3 [2](OH)CH : CH.CO 2 H is 
 formed by the protracted heating of the dimethyl ether with sodium 
 hydroxide. It suffers no change when heated with water, alcohol, or 
 hydrogen bromide (distinction from 3-nitro-cumarinic acid). The 
 methyl-ether acid, m.p. 193, is formed from 3-nitro-salicyl-aldehyde- 
 methyl ether, and from the dimethyl ether, m.p. 88, by the action of 
 soda (see above). This latter ether is produced when methyl iodide 
 acts upon the silver salt of the methyl-ether acid (B. 22, 1710). 
 
 f r "1/^TT . f^TT 
 
 Cumarin C 6 H 4 | , m.p. 70 and b.p. 290, occurs in 
 
 ( [ 2 ]0 CO 
 
428 ORGANIC CHEMISTRY 
 
 Asperula odorata, in the Tonka beans (from Dipterioc odor at a), and 
 in Melilotus officinalis. It is artificially prepared (i) by heating aceto- 
 o-cumaric acid (B. 10, 287), the reaction product resulting from acetic 
 anhydride and sodium salicyl-aldehyde (A. 147, 230), or from the 
 action of acetic anhydride and sodium acetate upon salicyl-aldehyde 
 (Perkin, sen., B. 8, 1599) ; (2) from phenol with malic acid and sul- 
 phuric acid ; (3) by reduction of /2-chloro- or /?-bromo-cumarin. 
 
 It has the agreeable odour of Asperula, and is applied in perfumery 
 for the preparation of the Asperula essence. 
 
 Cumarin dissolves rather easily in hot water, and very readily in 
 alcohol or in ether. It dissolves in caustic potash with a yellow colour, 
 the first product being potassium cumarinate, from which carbon 
 dioxide separates cumarin. Boiling concentrated caustic potash 
 changes it to potassium cumarate. In aqueous solution it is reduced 
 by sodium amalgam to melilotic acid, while sodium and alcohol reduce 
 it to oxy-hydro-cinnamic alcohol (B. 39, 2856). 
 
 When it is digested with an aqueous alcoholic solution of 
 potassium cyanide, hydrocyanic acid is added, and, upon subsequent 
 saponification, o-oxy-phenyl-succinic acid is formed (A. 293, 366). 
 Concerning the action of alkyl-magnesium haloids upon cumarin, 
 see B. 37, 489. 
 
 Cumarin-monomethyl-ester acid, m.p. 88, and cumarinic dimethyl 
 ester, b.p. 275, result when sodium cumarin is heated to 150 with 
 methyl iodide. When heated, both compounds change to the corre- 
 sponding o-cumaric acid derivatives, from which they can be recovered 
 by means of ultra-violet light. 
 
 Cumaroxime, m.p. 131 (B. 19, 1662), is produced when hydroxyl- 
 amine acts upon thio-cumarin. 
 
 Cumarin bromide C 9 H 6 O 2 Br 2 , m.p. 105, is produced when bromine 
 acts upon cumarin in carbon-disulphide solution. Alcoholic potash 
 
 ( [i]CH:CBr 
 
 converts it into a-bromo-cumarin C 6 HJ I . Boiling alcoholic 
 
 I [2jo do 
 
 potash changes both of these bodies into cumarilic acid (q.v.). 
 ( [i]CH : CH 
 
 Thio-cumarin C 6 H 4 4 | , m.p. 101, consists of golden-yellow 
 
 I [2]0 CS 
 
 needles. It is obtained from cumarin or o-cumaric acid by the action 
 of P 2 S 5 (B. 19, 1661). 
 
 3-Nitro-cumarinic acid NO 2 [ 3 ]C 6 H 3 /W^ :CH - COOH melts when 
 
 L [2JOH 
 
 rapidly heated, with the exit of water, at 150, and passes, on 
 gentle warming with water or alcohol, into the anhydride, 3-nitro- 
 cumarin, from which it is obtained, upon boiling with soda. It forms 
 long yellow prisms. The silver salt and methyl iodide yield 3-nitro- 
 cumarinic dimethyl ether. 
 
 Cumarin Homologues. Following method 2 (p. 426), and using 
 propionic, butyric, and iso-valerianic anhydrides, with their sodium 
 salts, the products are a-alkyl-cumarins. The fi-alkyl-ciimarins are 
 produced from phenols, aceto-acetic ester, and sulphuric acid (B. 17, 
 2188) by method 4. P 2 S 5 converts the a-alkyl-cumarins into a-alkyl- 
 thio-cumarins, which hydroxylamine changes to a-alkyl-cumarin 
 oximes (B. 24, 3459). 
 
DIOXY-PHENYL-OLEFIN-CARBOXYLIC ACIDS 429 
 a-Methyl-cumarin ^H 1 3 ^ m -P- 9. jS-Methyl-cumarin 
 
 For other homologous cumarins, see B. 39, 871 ; 41, 830 ; A. 367, 
 232 ; C. 1906, I. 933 ; 1908, II. 790 ; 1909, I. 373. 
 
 p-Amido-jS-methyl-cumarin, mono- and dimethyl-amido-j3-methyl- 
 cumarin, m.p. 230, 123, and 143, from amido-, monomethyl-, and 
 dimethyl-amido-phenol with aceto-acetic ester (B. 30, 277 ; 32, 3690). 
 
 m-Cumaric acid HO[3]C 6 H 4 .CH : CH.CO 2 H, melting at 191, has 
 been formed from m-amido-cinnamic acid and from m-oxy-benz- 
 aldehyde (B. 15, 2049, 22 97)- 
 
 Nitro-m-cumaric acids, see B. 22, 292. 
 
 o-Amido-m-cumaric acid has been obtained electrolytically from 
 o-nitro-cinnamic acid (B. 27, 1936). 
 
 p-Cumarie acid HO[4]C 6 H .CH : CH.CXXH, melting at 206, is 
 obtained from p-amido-cinnamic acid and from p-oxy-benzaldehyde ; 
 also on boiling the extract of aloes with sulphuric acid (preparation, 
 B. 20, 2528), and by the decomposition of the glucoside naringin (q.v.). 
 
 Methyl-p-eumarie acid, from anisic aldehyde, melts at 154. The 
 phenol-alkyi ethers of the cumaric acids yield ethers of unsaturated 
 phenols (see o- and p-vinyl-anisol), just as styrol is obtained from /?- 
 bromo-hydro-cinnamic acid by the action of hydrogen bromide, and then 
 a soda solution, when carbon dioxide is eliminated. 
 
 jS-p-Methoxy-phenyl-methacrylic acid CH 3 O[4]C 6 H 4 .CH : C(CH 3 ). 
 COOH, melting at 154, is obtained from anisic aldehyde and propionic 
 acid. It breaks down, when heated, into carbon dioxide and anethol. 
 
 B. Dioxy-phenyl-olefin-earboxylic Acids. Caffeic acid, or 3, 4~di- 
 oxy-cinnamic acid, corresponding to proto-catechuic acid and umbellic 
 acid, or 2, 4-dioxy-cinnamic acid, are the most important of the known 
 dioxy-cinnamic acids, because they themselves, or their simple deriva- 
 tives, occur in plants or appear as decomposition products of vegetable 
 substances, and 3-methyl-caffeic acid, or ferulic acid, can be changed 
 to the valuable vanillin. 
 
 Caffeic acid, jS-3, ^-dioxy-phenyl-acrylic acid, 3, ^-dioxy-cinnamic 
 acid, and its methyl- and methylene-ester acids, when reduced, become 
 hydro-caffeic acid and its ether acids. Oxidation yields proto-catechuic 
 acid and its ethers. When the aceto-derivatives of the two methyl- 
 caffeic acids are oxidised with potassium permanganate, the first 
 products are the aceto-derivatives of the two methyl-ether-proto-cate- 
 chuic aldehydes. The caffeic acids and their ether acids can be 
 synthesised from proto-catechuic aldehyde and its ethers with the aid 
 of the Perkin reaction. When fused with caustic potash, caffeic acid 
 and its ether acids yield proto-catechuic acid and acetic acid : 
 
 f [i]CO : CH.CO 2 H / [i]CH : CH.CO 2 H f [i]CH : CH.CO,H 
 
 C 6 H 3 [ 3 ]OH C 6 H 3 \ [ 3 ]OCH 3 C 6 H 3 -| [ 3 ]OH 
 
 l[ 4 ]OH l[ 4 ]OH l[ 4 ]OCH 3 
 
 Cafifei'c acid, m.p. 213 Ferulic acid, m.p. 169 Iso- ferulic acid, m.p. 228 
 
 (yields vanillin) (yields iso vanillin) . 
 
 Caffeic acid is produced when coffee tannic acid is boiled with 
 potassium hydroxide. It occurs in Cicutavirosa (B. 17, 1922). Ferric 
 
430 ORGANIC CHEMISTRY 
 
 chloride produces a green coloration in its solutions, which sodium 
 carbonate changes to a dark-red colour. 
 
 Ferulic acid, m-methoxy-p-oxy-cinnamic acid, occurs in the resin of 
 asafcetida, and has been obtained from vanillin as well as from m- 
 methoxy-p-nitro-cinnamic acid, the product resulting from the action 
 of nitric acid upon m-methoxy-cinnamic acid ether (B. 18, R. 682). 
 Its aceto-compound melts at 196. 
 
 Iso-ferulic acid, m-oxy-methoxy-cinnamic acid, hesperitinic acid, was 
 first obtained from the glucoside hesperidin (q.v.). Both methyl 
 ethers can also be prepared by a partial methylation of caffeic acid, 
 when the chief product will be iso-ferulic acid. Its aceto-derivative melts 
 at 199. 
 
 Dimethyl-eaffeie acid (CH 3 O) 2 [3, 4]C 6 H 3 .CH : CH.CO 2 H, melts at 
 181 (B. 14, 959). 
 
 Piperonyl-aerylic acid (CH 2 O 2 )[3, 4]C 6 H 3 .CH : CH.CO 2 H melts at 
 232 (B. 13, 757). 
 
 Diaceto-caffeic acid (CH 3 CO 2 ) 2 [3, 4]C 6 H 3 .CH : CH.CO 2 H melts at 
 190 (B. 11, 686). 
 
 a-Homo-caffeic acid, 3, 4-dioxy-a-methyl-cinnamic acid, melts at 
 193. Its monomethyl-ether acid, homo-ferulic acid (CH 3 O)(OH)[3, 4] 
 C 6 H 3 .CH : C(CH 3 ).COOH, melting at 168, yields iso-eugenol when it 
 is heated with lime (B. 15, 2063). 
 
 a-Hydro-piperie acid (CH 2 2 )[3, 4]C 6 H 3 CH 2 .CH : CH.CH 2 .CO 2 H, 
 melting at 78, is formed when sodium amalgam acts upon piperic acid. 
 When boiled with caustic soda it changes to jS-hydro-piperic acid 
 (CH 2 2 )[3, 4]C 6 H 3 .CH 2 .CH 2 .CH : CH.CO 2 H, melting at 131. Sodium 
 amalgam converts the j3-acid into piper-hydronic acid (CH 2 O 2 )[3, 4] 
 C 6 H 3 [CH 2 ] 4 CO 2 H, melting at 98. 
 
 Umbellic acid, 2, 4-dioxy-cinnamic acid (HO) 2 [2, 4]C 6 H 3 .CH : CH. 
 CO 2 H, decomposes about 240. It is produced on boiling umbelliferone 
 with KHO ; the 2, 4-dimethoxy-cinnamic acid, m.p. 184, is formed 
 from dimethyl-resorcyl-aldehyde by Perkin's synthesis (C. 1903, I. 580 ; 
 1904, I. 724). 
 
 ( rTld-T CTT 
 
 Umbelliferone, 4-oxy-cumarin HO[4]C 6 H 3 4 I , melting at 
 
 ([ 2 ]0 CO 
 
 240, is found in the bark of Daphne mezereum, and is obtained by dis- 
 tilling different resins, such as galbanum and asafcetida. It is obtained 
 synthetically from j8-resorcyl-aldehyde by method 2 ; and also by the 
 condensation of resorcin with malic acid according to method 3. It 
 has an odour resembling that of cumarin, and behaves similarly 
 with caustic potash. Its alkyl ethers show isomeric phenomena 
 analogous to those developed under o-cumaric acid and cumarin 
 (B. 19, 1778). 
 
 j8 - Methyl-umbelliferone, 4 - oxy - B - methyl-cumarin, resocyanin, 
 
 r[i]C(CH 3 ):CH 
 
 si 
 
 H O[4]C 6 H 3 -] I , melting at 185, is formed when sulphuric acid 
 
 ( [2]0 CO 
 
 acts upon resorcin and aceto-acetic ester or acetyl-cyanacetic ester 
 (B. 26, R. 314). Also from p-amido-methyl-cumarin (B. 26, R. 314) ; 
 on melting with potash it gives resaceto-phenone. Nitro- and amido- 
 methyl-umbelliferone, see B. 34, 660. 
 
 a, 0-Dimethyl-umbelliferone melts at 256 (B. 16, 2127). 
 
TRIOXY-CINNAMIC ACIDS 431 
 
 The corresponding bodies have been prepared from orcin according 
 to methods 3 and 4 (B. 17, 1649, 2188) 
 
 2, 5-Dioxy-cinnamie acid, m.p. 207, from o-cumaric acid by oxida- 
 tion with KMnO 4 in alkaline solution (C. 1907, II. 901). 
 
 3-Oxy-cumarin, melting at 28o-285 with decomposition, and 
 5-oxy-cumarin, melting at 249, are produced when pyro-catechol and 
 hydroquinone are treated with malic acid and sulphuric acid (B. 18, 
 
 R. 333). 
 
 5-Oxy-/3-methyl-cumarin, m.p. 243, from hydroquinone, aceto- 
 acetic ester, and sulphuric acid (B. 40, 2731). 
 
 C. Trioxy-cinnamic Acids. Inner anhydrides, 8-lactones of trioxy- 
 cinnamic acids, are daphnetin, 3, 4-dioxy-cumarin, melting at 255, 
 and aesculetin, 4, $-dioxy-cumarin, the aromatic decomposition pro- 
 ducts of the isomeric glucosides daphnin and aesculin. Synthetically 
 they have been obtained from pyrogallic aldehyde, or oxy-hydro- 
 quinone-aldehyde, acetic anhydride, and sodium acetate (B. 32, 287). 
 
 /Esculetinic and daphnetic acids are the trioxy-cinnamic acids corre- 
 sponding to these dioxy-cumarins. They are only known as ether 
 acids and ether esters. Potassium permanganate oxidises the triethyl 
 ethers to triethoxy-benzoic acids, which become triethoxy-benzols 
 through the loss of carbon dioxide (B. 15, 2082 ; 17, 1086 ; 20, 1119). 
 
 Methyl-aesculetin, ^-oxy-^-methoxy-cumarin, m.p. 203, is identical 
 with gelseminic acid from Gelsenium sempervivens, and also with 
 chrysatropic acid from Atropa belladonna (C. 1898, II. 635 ; B. 
 31/1189). 
 
 jS-Methyl-aesculetin, 4, 5-dioxy-j8-methyl-cumarin, m.p. 270, from 
 oxy-hydroquinone triacetate with aceto-acetic ester, and sulphuric 
 acid (B. 34, 423). 
 
 Sinapinic acid, oxy-dimethoxy-cinnamic acid (CH 3 O) 2 [3, 5] (OH) [4] 
 C 6 H 2 CH : CHCOOH, m.p. 192, has been obtained from white mustard 
 seeds, and, synthetically, from syringa aldehyde by Perkin's reaction 
 (B. 36, 1031). Methyl-sinapinic acid, 3, 4, ^-trimethoxy-cinnamic acid, 
 m.p. 124, from trimethyl-gallic aldehyde (B. 41, 2536). 4, 6-Dioxy- 
 cumarin, m.p. 273, from phloro-glucin-aldehyde by Perkin's reaction. 
 On methylation it yields eitroptene, limettin, 4, 6-dimethoxy-cumarin, 
 m.p. 147, from the ethereal oils of certain species of Citrus (C. 1904, 
 
 ii. 105). 
 
 D. Tetraoxy-cinnamic Acids. Fraxetin, melting at 227, the 
 aromatic decomposition product of the glucoside of fraxin (q.v.), con- 
 tains the monomethyl ether of a trioxy-cumarin. Isomerides of fraxetin 
 have been prepared synthetically (B. 27, R. 130 ; 29, R. 293). 
 
 E. Phenyl - acetylene - earboxylic Acids. Phenyl - propiolie acid 
 C 6 H 5 .C ; C.CO 2 H, m.p. 136, is obtained by boiling a- and -bromo- 
 cinnamic acids with alcoholic potash, by acting upon sodium phenyl- 
 acetylene with carbon dioxide (1870, Glaser, A. 154, 140), and when 
 the latter, and sodium, act upon cu-bromo-styrol. It is prepared by 
 boiling the dibromide of cinnamic acid, or its ethyl ester, with alcoholic 
 potash (B. 34, 3647 ; 36, 902). Heated in water to 120, it decomposes 
 into phenyl-acetylene and CO 2 . On heating with acetic anhydride, 
 or by the action of POC1 3 , phenyl-propiolic acid passes into the anhy- 
 dride of i-phenyl-naphthalin-2, 3-dicarboxylic acid (B. 40, 3372 ; 
 C. 1908, II. 1357). Similarly, phenyl-propiolic ester polymerises, on 
 
432 ORGANIC CHEMISTRY 
 
 heating to 200, to form phenyl-naphthalin-dicarboxylic ester (B. 40, 
 3839 ; see the formation of trimesinic acid from propiolic acid). 
 
 On adding hydrogen, by means of sodium amalgam, it becomes 
 hydro-cinnamic acid ; treated with zinc dust and glacial acetic acid, or 
 sodium and alcohol, it becomes cinnamic acid (B. 22, 1181) ; with 
 hydrogen in the presence of colloidal palladium, allo-cinnamic acid ; 
 and, by addition of HC1 and HBr, it yields j3-halogen and allo-j8- 
 halogen-cinnamic acid. It unites with halogens to form phenyl- 
 dihalogen-acrylic acids; with hydrazin hydrate and phenyl-hydrazin 
 it forms 3-phenyl-pyrazolone and i, 3-diphenyl-pyrazolone (B. 27, 
 783). Similarly, phenyl-propiolic acid unites with other amine bases 
 (C. 1900, I. 547 ; 1908, I. 233), as well as the sodium compound of 
 j8-diketones, aceto-acetic ester, and malonic ester. In the last- 
 mentioned reaction a tricarboxylic acid is obtained which, on dis- 
 carding CO 2 , becomes phenyl-glutaconic acid (B. 27, R. 163 ; C. 1899, 
 II. 608). On digesting with sodium alcoholates one or two molecules 
 of alcohol are attached, and jS-alkoxy-cinnamic ester is formed, or 
 dialkyl acetals of benzoyl-acetic ester (C. 1904, I. 659 ; 1906, I. 1551). 
 Phenyl-propiolic-acid nitrile unites with one molecule of a primary or 
 secondary amine to form j8-alkyl-amido-cinnamic-acid nitriles, such as 
 C 6 H 5 C(NHCH 3 ) : CH.CN, which, with acids, regenerate the amine and 
 form benzoyl-aceto-nitrile (C. 1906, II. 1842). 
 
 Phenyl-propiolic ethyl ester C 6 H 5 C ; C.CO 2 C 2 H 5 , b.p. 22 153, is also 
 formed from sodium-phenyl-acetylide, with chloro-carbonic ester. It 
 easily transforms into benzoyl-acetic ester by hydration (A. 308, 280). 
 Phenyl-propiolic acid nitrile C 6 H 5 C : CCN, m.p. 39, is formed from the 
 amide with P 2 O 5 ; from sodium-phenyl-acetylide with gaseous HCN ; 
 and from phenyl-propargyl-aldoxime with acetic anhydride (B. 36, 
 3671). Chloride, b.p. 25 131; amide, m.p. 102 (B. 25, 3537; 29, 
 R. 795 ; C. 1906, I. 651). 
 
 o-Nitro-phenyl-propiolic acid decomposes at 156. It is obtained 
 when alcoholic potash acts upon the dibromide of o-nitro-cinnamic 
 acid (Baeyer, A. 212, 140). When boiled with water it decomposes 
 into carbon dioxide and o-nitro-phenyl-acetylene. When boiled with 
 alkalies it yields isatin. 
 
 It dissolves in concentrated sulphuric acid, with conversion into 
 the isomeric isatogenic acid, which, at once, forms carbon dioxide and 
 isatin. Its silver salt explodes with great violence when it is heated. 
 
 If digested with alkaline reducing agents (grape-sugar and potassium 
 hydroxide, ferrous sulphate, hydrogen sulphide, potassium xanthate), 
 it readily changes to indigo blue (Baeyer, 1880 ; B. 13, 2259). 
 
 The ethyl ester of the acid is obtained by conducting hydrochloric 
 acid gas into a mixture of the acid and alcohol. It melts at 6o-6i. 
 When it is dissolved in sulphuric acid it changes to the isomeric isato- 
 genic ester. Ammonium sulphide reduces it to the indoxylic ester 
 (B. 14, 1741) : 
 
 Isatogenic ester o-Nitro-phenyl-propiolic ester Indoxylic ester. 
 
 p-Nitro-phenyl-propiolic acid, m.p. 198, is formed from the p-nitro- 
 cinnamic ester after the same manner as the ortho-acid. When boiled 
 with water it breaks up into carbon dioxide and p-nitro-phenyl-acety- 
 
PHENYL-DIOLEFIN-CARBOXYLIC ACIDS 433 
 
 lene. It yields p-nitro-aceto-phenone if digested at 100 with sul- 
 phuric acid. 
 
 The ethyl ester, m.p. 126, when digested with sulphuric acid at 
 35, forms p-nitro-benzoyl-acetic acid. 
 
 c-Amido-phenyl-propiolic acid melts at 129 with decomposition 
 into CO 2 and o-amido-phenyl-acetylene. It is obtained by reducing 
 o-nitro-phenyl-propiolic acid with ferrous sulphate and ammonia 
 (B. 16, 679). It separates as a yellow crystalline powder. When 
 boiled with water it yields o-amido-aceto-phenone. 
 
 y-Chloro-carbo-styril results when the acid is boiled with hydro- 
 chloric acid, and y-oxy-carbo-styril upon heating it with sulphuric 
 acid (B. 15, 2147) : 
 
 fCCl:CH\ +HCI ;[i]CEEC.C0 2 H fC(OH) : CH\ 
 C ' H \N / C01 *Ili^- C H H[2]NH 2 C H \N- ^ C 
 
 Sodium nitrite converts the hydrochloride into the diazo-chloride, 
 which at 70 yields cinnolin-oxy-carboxylic acid. 
 
 m-Methyl-phenyl-propiolic acid CH 3 [3]C 6 H 4 C : C. CO 2 H melts at 
 109 (B. 20, 1215). 
 
 F. Phenyl-diolefln-carboxylic acids have been prepared from cin- 
 namic aldehyde by means of the Perkin reaction. Cinnamylidene- 
 acetic acid, cinnamenyl-acrylic acid CgHg.CH : CH.CH : CH.CO 6 H 
 melts at 165, from cinnamic aldehyde, pyridin, and malonic acid with 
 heat, by decomposition of the cinnamylidene-malonic acid first formed 
 together with the stereo-isomeric allo-cinnamylidene-acetic acid, m.p. 
 138 ; on overheating it discards CO 2 and passes into phenyl-butadiene 
 (B. 35, 2696). 
 
 The nitrile, boiling at 285, is obtained from cinnamenyl-cyano- 
 acrylic acid. The o- and p-nitro-acids, melting at 217 and 271, were 
 obtained from o- and p-nitro-cinnamenyl-acetone by the action of 
 NaQO (A. 253, 356). The o-amido-acid melts with decomposition at 
 176 (B. 18, 2332). Cinnamenyl-crotonic acid and cinnamenyl-angelica 
 acid melt at 157 and 126 (C. 1906, I. 349). 
 
 Piperic acid, 3, ^-methylene-dioxy-cinnamenyl-acrylic acid (CH 2 O 2 ) 
 [3, 4]C 6 H 3 .CH : CH.CH : CH.CO 2 H, melting at 217, is produced, 
 together with piperidin, when piperin is boiled with alcoholic potassium 
 hydroxide. It can be synthesised by aid of the Perkin reaction, 
 from piperonyl-acrolein, and from piper onylene-malonic acid (B. 28, 
 1190). Sodium amalgam converts it into two isomeric hydro-piperic 
 acids, a and /?. It combines with four atoms of bromine. It is oxidised, 
 in dilute solution by potassium permanganate at o, to piperonal and 
 racemic acid (B. 23, 2372). When fused with potassium hydroxide it 
 breaks down into acetic, oxalic, and proto-catechuic acids. Its chloride 
 and piperidin form piperin (q.v.). 
 
 History. Fittig and Mielck (1874) determined the constitution of 
 piperic acid. Ladenburg and Scholtz (1894) effected its synthesis 
 (B. 27, 2958). 
 
 a-Methyl- and a-ethyl-piperic acids, melting at 208 and 179, were 
 synthesised just like piperic acid (B. 28, 1187). 
 
 j8-Cinnamylidene-propionic acid C,H 6 CH : CH.CH : CH.CH 2 COOH, 
 m.p. 112, is formed, in small quantities, on condensation of cinnamic 
 aldehyde and sodium succinate with acetic anhydride (A. 331, 162). 
 VOL. II. 2 F 
 
434 ORGANIC CHEMISTRY 
 
 IV. COMPOUNDS WHICH MAY BE VIEWED AS OXIDATION PRODUCTS OF 
 
 MONONUCLEAR-AROMATIC POLYALCOHOLS WITH UNSATURATED 
 
 SIDE CHAINS. 
 
 The domain of the aromatic poly alcohols having unsaturated side- 
 chains has been even less completely, and even more irregularly, 
 developed than that of the polyhydric aromatic paraffin alcohols and 
 their oxidation products. At present the alcohols and aldehydes are 
 wholly lacking ; from them the carboxylic acids and their derivatives 
 belonging here can be theoretically deduced. Consequently the 
 material in this section will not be sharply differentiated, although, 
 in the main, the classification is the same as that observed with the 
 oxidation products of the aromatic polyparamn alcohols. 
 
 i. Phenylene-oxy-olefin-carboxylic Acids. Methylene-phthalide and 
 iso-cumarin are inner anhydrides, or lactones, of the possible o-vinyl- 
 alcohol-benzoic acids. They are not known in a free state. Cumarin 
 is isomeric with them. 
 
 Methylene-phthalide C 6 H 4 ( 2 , m.p. 59, is formed in the 
 
 l[2]COO 
 distillation of phthalyl-acetic acid. Its dibromide melts at 98. Mono- 
 
 ,[i]C=CHBr 
 
 bromo-methylene-phthalide C 6 H 4 { \ is produced by the action 
 
 l[2]CO.O 
 
 of bromine upon o-aceto-phenone-carboxylic acid. Diehloro-methylene- 
 
 phthalide C 6 H 4 { * \~ 2 melts at 128. It is formed, together with 
 l[2]COO 
 
 ,CC1.CC1 3 
 tetraehloro-methyl-phthalide C 6 H 4 { \ , melting at 93, upon con- 
 
 VCOO 
 
 ducting chlorine into a mixture of glacial acetic acid and phthalyl- 
 chloracetic acid (A. 255, 383 ; 268, 294). 
 
 Bromo-methylene-phthalide, m.p. 140, from aceto-phenone-o-car- 
 boxylic acid, with bromine. Dibromo-methylene-phthalide, m.p. 140, 
 from a-dibromaceto-phenone-o-carboxylic acid on heating with con- 
 centrated sulphuric acid (B. 40, 83). 
 
 r [i]C=CH 2 
 Derivatives of methylene-phthalimidin C 6 HJ ~--^ have been 
 
 l[2]CO.NR 
 
 prepared by the action of amines and amino-acids upon o-aceto- 
 phenone-carboxylic acid (B. 29, 2518). 
 
 fC=CHNO 2 
 Nitro-methylene-phthalide C 6 H 4 { \ , m.p. 207 with de- 
 
 vco.o 
 
 composition, from phthalic anhydride and nitro-methane, is split up 
 by alkali to nitro-phenaeyl-o-carboxylie acid NO 2 CH 2 COC 6 H 4 COOH, 
 m.p. 121 (B. 36, 570). 
 
 {Ti~lC=CH CH 
 
 Ethylidene-phthalide C 6 H 4 < 3 melts at 64 (B. 19, 838). 
 
 ( [2]COO 
 
 Propylidene- and iso-butylidene-phthalides, boiling at 170 (12 mm.) 
 and melting at 97, are obtained by condensing phthalic anhydride 
 with the sodium salts and anhydrides of propionic, butyric, and iso- 
 valeric acids. Water and carbon dioxide are eliminated (B. 29, 1436). 
 
 These alkylidene phthalides are transposed by sodium ethylate 
 into the isomeric diketo-hydrindenes. B}' alkaline hydrates, they are 
 
PHENYLENE-OXY-OLEFIN-CARBOXYLIC ACIDS 435 
 
 split up into o-ketone-carboxylic acids. Ethylene-phthalide gives rise 
 to propio-phenone-o-carboxylic acid. 
 
 r -IpfT__QTT 
 
 Iso-cumarin C 8 H 4 | L J ~ i , melting at 47 and boiling at 
 
 285, is formed in the distillation of silver iso-cumarin-car boxy late. It 
 readily volatilises with steam. When digested with soda it becomes : 
 Anhydro-o-oxy-vinyl-benzoic acid O(CH : CH[2]C 6 H 4 .CO 2 H) 2 , 
 melting at 183. When this body is heated with hydrochloric acid to 
 160 the anhydride O(CH : CH[2]C 6 H .CO) 2 O, melting at 234, results. 
 The imide O(CH : CH[2]C 6 H 4 CO) 2 NH, melting at 285, is produced 
 when alcoholic ammonia acts upon the anhydride at 170 (B. 27, 207). 
 
 _ r T ~i(~ > ~H[ CH 
 
 Iso-carbo-styril C 6 H 4 / L J ^\ , melting at 208, is isomeric 
 
 with carbo-styril, the lactame corresponding to iso-cumarin. It is 
 formed when iso-cumarin is heated to 130 with alcoholic ammonia, and 
 upon heating iso-carbo-styril-carboxylic acid or its silver salt. It yields 
 iso-quinolin when distilled with zinc dust (B. 27, 208). 
 
 3-Methyl-iso-cumarin C ^^^ = _^ C ^> melting at 118, is 
 
 /[i]C=C(0 2 CCH 3 )CH 3 
 formed when \L-diacetyl-cyano-benzyl-cyanide C 6 HJ \ 
 
 l[2]CNCN 
 
 melting at 135, is heated to 180 with hydrochloric acid. This latter 
 body results from the action of sodium acetate and acetic anhydride 
 upon o-cyano-benzyl cyanide (B. 27, 831). Similarly, o-cyano-benzyl 
 cyanide furnishes an additional series of homologues of iso-cumarin, 
 all of which are characterised by their ready transposition into iso- 
 carbo-styrils (see B. 29, 2543, etc.). 
 
 Ammonia converts 3-methyl-iso-cumarin into the corresponding 
 3-methyl-iso-carbo-styril, melting at 211 (B. 25, 3563). 
 
 By boiling in KHO methyl-iso-cumarin is transformed into methyl- 
 benzyl-ketone-o-carboxylic acid. 
 
 CH=CH^ CCH=CH 
 
 Bergaptene Lc 6 H(OCH 3 H I (?), melting at 188, 
 
 1 o J [O CO 
 
 appears to be a derivative of oxy-vinyl-cumarin. It separates, on 
 standing, from raw bergamot oil, which is obtained by pressing out the 
 fresh rinds of Citrus Bergamia, Risso (B. 26, R. 234). 
 
 2 . Phenylene - aldehydo - carboxylic A cids. p - Aldehyde - cinnamic 
 acid CHO[4]C 6 H 4 .CH : CH.C0 2 H, melting at 247, is obtained from 
 terephthal-aldehyde by the Perkin reaction (A. 231, 375 ; B. 34, 2784). 
 
 3. Phenylene -dicarboxylic Acids. o - Cinnamyl - carboxylic acid 
 CO 2 H[2]C 6 H 4 .CH.CH.CO 2 H, m.p. 174, reverts again to phthalidacetic 
 acid. It is produced when phthalidacetic acid is digested with alkalies, 
 and by carefully oxidising j3-naphthol with potassium permanganate 
 (B. 21, R. 654). More energetic oxidation produces carbo-phenyl- 
 glyoxylic acid. 
 
 o-Cyano-cinnamie acid CN[2]C 6 H 4 CH : CH.CO 2 H, m.p. 252, is 
 produced when sodium acetate and acetic anhydride act upon a-cyano- 
 benzal chloride, and also from o-amido-cinnamic acid (B. 24, 2574 ; 
 27, R. 262). Its formation from the Na salt of jS-nitroso-naphthol 
 
 fC(NO) :C(OH) 
 C 8 H 4 -j I by heating to 250 is worthy of note (C. 1901, 1. 69). 
 
 1 CH - CH 
 
436 ORGANIC CHEMISTRY 
 
 p-Cinnamyl-carboxylic acid is obtained from terephthal-aldehydic 
 acid and sodium acetate. It is an insoluble, infusible powder (A. 231, 
 
 369). 
 
 o - Phenylene - diaerylie acid C 6 H 4 [i, 2](CH : CH.CO 2 H) 2 melts 
 above 300. It is produced when alcoholic potash acts upon 
 o-xylylene-dichloro-dimalonic ester, or from o-phthal-aldehyde by 
 Perkin's reaction (B. 19, 435 ; A. 347, 117). 
 
 p-Phenylene-diaerylic acid is obtained from p-aldehydo-cinnamic 
 ester with sodium acetate and acetic anhydride (A. 231, 377), and from 
 p-xylylene-dibromo-dimalonic ester (B. 34, 2784). 
 
 4. Phenyl-olefin-ketols. Oxy - methylene - aceto - phenone C 6 H 5 .CO. 
 CH : CH.OH, when separated from its sodium compound, is a very 
 unstable oil. Its sodium derivative is formed when sodium ethylate 
 acts upon formic ester and aceto-phenone. Formerly, oxy-methylene- 
 aceto-phenone was considered to be benzoyl-acetaldehyde. As to the 
 constitution of the oxy-methylene compounds, see Vol. I. With 
 phenyl-iso-cyanate it yields an O-carbanilido-derivative, m.p. 125, 
 which, by the action of potassium carbonate, is easily transposed to 
 the isomeric C-carbanilide, m.p. 94 (B. 37, 4631). Phenyl-hydrazin 
 converts it into diphenyl-pyrazol (q.v.) ; hydroxylamine unites with 
 it to form benzoyl-acetaldoxime. See also Benzylidene phenoxy- 
 acetone. 
 
 5, 6. Phenyl - oxy - olefin - and diolefin - carboxylic Acids. Oxy- 
 methylene-phenyl-acetic ester C 6 H 5 C(CO 2 C 2 H 5 ) : CHOH see Fonnyl- 
 phenyl-acetic ester. 
 
 j8-Methoxy-einnamic ester C 6 H 5 C(OCH 3 ) : CHCO 2 C 2 H 5 , b.p. 14 155, 
 and j8-ethoxy-einnamic ester, b.p. 16 168, are formed from phenyl- 
 propiolic acid ester with sodium alcoholate, and from benzoyl-acetic 
 ester with ortho-formic acid ether. The corresponding acids melt at 
 180 and 162 respectively, discarding CO 2 and forming j8-phenyl- 
 vinyl-methyl and ethyl ethers (B. 29, 1005 ; C. 1904, I. 659, 719). 
 j3-Phenoxy-cinnamic ester C 6 H 5 C(OC 6 H 5 ) : CHCOOC 2 H 5 , m.p. 76, 
 b.p. 10 265, is obtained by attaching sodium phenolate to phenyl-pro- 
 piolic acid ester ; the acid, m.p. 143, yields on heating CO 2 and j8-phen- 
 .oxy-styrol C 6 H 5 C(OC 6 H 5 ) : CH 2 (C. 1900, II. 247 ; 1901, II. 410, 1052 ; 
 1906, I. 1551). a-Phenoxy-einnamic acid C 6 H 5 CH : C(OC 6 H 6 )COOH, 
 m.p. 181, is obtained from benzaldehyde, sodium phenoxy-acetate, 
 and acetic anhydride by synthesis ; also from benzylidene-phenoxy- 
 acetone with alkali hypochlorite by disintegration (B. 35, 3555). On 
 heating it partly decomposes into CO 2 and a>-phenoxy-styrol, partly 
 into CO and phenyl-acetic phenyl ester (B. 38, 1958). 
 
 y-Phenyl-a-oxy-crotonie acid, styrol-a-oxy-acetic acid C 6 HgCH : 
 CH.CH(OH)COOH, m.p. 137, is prepared by saponifying its nitrile, 
 cinnamyl-aldehyde cyano-hydrin, m.p. 74, with cold concentrated 
 hydrochloric acid ; or by reduction of cinnamyl-formic acid with Na 
 amalgam. On boiling with hydrochloric acid the acid is readily re- 
 arranged to benzoyl-propionic acid (B. 37, 3124), whereas by boiling 
 with NaHO benzyl-pyro-racemic acid is formed. Heated alone or 
 with acetic anhydride, benzoyl-propionic acid yields y-phenyl-A 2 - 
 
 croto-lactone C p H 5 t : CH.CH 2 COO, m.p. 91, from which benzoyl- 
 propionic acid is easily regenerated. Another derivative of phenyl- 
 
PHENYL-OXY-OLEFIN-CARBOXYLIC ACIDS 437 
 
 a-oxy-crotonic acid is probably trichloro - methyl - styrol - carbinol 
 CC1 3 CH(OH)CH : CHC 6 H 5 , m.p. 67, obtained from cinnamic aldehyde 
 with chloroform, which, on heating with water, or alkalies, also yields 
 benzoyl-propionic acid (A. 299, i ; C. 1900, II. 238). 
 
 /CH 2 CO 
 jS-Benzyl-angelica-lactone C 6 H 5 .CH 2 C/ \ is obtained- in the 
 
 distillation of benzyl-lsevulinic acid. 
 
 j3-0xy-eumarin C 6 H 4 {[* ( ^_^, m.p. 206, is formed from its 
 
 carboxylic ester by saponification and detachment of CO 2 . In its 
 properties, solubility in alkaline carbonate, formation of an oximido- 
 compound with sodium nitrite, capacity of condensation with aldehydes, 
 etc., it resembles the aliphatic tetronic acids, and it has therefore also 
 been called benzo-tetronic acid. On heating with concentrated alkalies, 
 oxy-aceto-phenone is formed (A. 379, 333). j3-Ethoxy-eumarin, m.p. 
 174, is formed, from the silver salt, with IC 2 H 5 . With PC1 5 and PBr 5 , 
 j8-oxy-cumarin gives j3-chloro- and jS-bromo-cumarin, m.p. 92 and 91 
 respectively, which are reduced with zinc dust and alcohol to cumarin. 
 Methylene-bis-benzo-tetronic acid (c 6 H 4 {^ |j_ o ) CH 2 , m.p. 
 
 about 206, and ethylidene-bis-benzo-tetronic acid, m.p. 165, from 
 benzo-tetronic acid with formaldehyde and acetaldehyde respectively 
 (A. 367, 169). Homologous and substituted /2-oxy-cumarins have been 
 prepared by starting from the corresponding substituted salicylic 
 chlorides (A. 367, 219 ; 368, 23). 
 
 S-Oxy-einnamylidene-aeetie Acid. Its lactone is phenyl-cumalin 
 C 8 H 5 .C : CH.CH : CH.CO 
 
 I I , melting at 68, and found in coto bark (B. 29, 
 
 2659 ; R. 1116). 
 
 From a phenyl-oxy-triolefin-carboxylic acid we derive cinnamyli- 
 
 dene - dimethyl - eroto - lactone c 6 H 6 CH : CH.CH : C.C(CH 3 ) : C(CH 3 )> m -P- 
 153, obtained by condensation of phenyl-iso-crotonic acid and pyro- 
 cinchonic anhydride (A. 306, 242). 
 
 7. Phenyl-dioxy-olefin-carboxylic Acids. Oxy-methylene-phthalide 
 
 ( [i]C=CHOH 
 C 6 H 4 4 f m.p. 148, from o-bromo-aceto-phenone-o-carboxylic 
 
 l[ 2 ]CO.O 
 
 acid on boiling with water ; with hydroxylamine and phenyl-hydrazin, 
 it reacts in the desmotropic form as formyl-phthalide, with the forma- 
 tion of an oxime, m.p. 152, and a phenyl-hydrazone, m.p. 180 with 
 decomposition (B. 40. 74). 
 
 8, 9. Phenyl-olefin- and diolefin-a-keto-carboxylic Acids result from 
 the condensation of aromatic aldehydes with pyro-racemic acid. 
 
 Cinnamyl-formie acid C 6 H 5 .CH : CH.CO.CO 2 H, a light yellow 
 rubber-like mass, from benzaldehyde, pyro-racemic acid, and HC1. 
 With XaHO we obtain the acid in bright flakes -f H 2 O, melting at 
 57 when anhydrous ; on reduction with a sodium amalgam it gives 
 y-phenyl-a-oxy-crotonic acid (B. 36, 2527). The syrupy acid is also 
 formed from its nitrile, cinnamyi cyanide C 6 H 5 .CH : CH.CO. CN, m.p. 
 114 (B. 14, 2472). 
 
 o-Nitro-einnamyMormic acid NO 2 [2]C 6 H 4 .CH : CH.CO.COOH, m.p. 
 
438 ORGANIC CHEMISTRY 
 
 135, from o-nitro-benzaldehyde with pyroracemic acid. It is con- 
 verted into indigo by alkalies in the cold, discarding oxalic acid. 
 
 3,4- Methylene - dioxy - cinnamyl - formic acid (CH 2 O 2 ) [3 , 4] C 6 H 3 . 
 CH : CH.CO.CO 2 H, m.p. 149, and piperonylene-pyro-racemic acid 
 (CH 2 O 2 )[3, 4]C 6 H 3 CH :CH.CH.CH.CO.CO 2 H, m.p. 166, are formed 
 from piperonal and piperonyl-acrolein. 
 
 Cinnamylidene-pyro-raeemic acid C 6 H 5 CH : CH.CH : CH.COCOOH, 
 m.p. 107, from cinnamic aldehyde and pyro-racemic acid, is reduced by 
 sodium amalgam to the corresponding a-oxy-acid, which is trans- 
 formed, by boiling with HC1, into S-benzal-lsevulinic acid (B. 37, 1318). 
 
 10. Phenyl-olefin-fi-ketone-carboxylic Acids result from the con- 
 densation of aceto-acetic ester, and aromatic aldehydes, with hydro- 
 chloric acid gas, or, better, with primary or secondary amines in the 
 
 cold (B. 29, 172). Benzal-aceto-acetic ester C 6 H 5 .CH : c<(^^ H5 , m.p. 
 
 59, b.p. 181 (17 mm.) (A. 281, 63). The m-mVro-ester melts!at 112 
 (B. 26, R. 448). y-Benzal-diethyl-aeeto-acetic ester C 6 H 5 .CH : CH.COC 
 
 (C,H 5 ) 2 .C0 2 C 2 H 5 , m.p. 101. Acetyl-cumarin C 6 H 4 {[^^ O CO :H , 
 
 m.p. 124, from aceto-acetic ester, salicyl-aldehyde, and acetic anhy- 
 dride. It has feebly acid qualities; see Cumarin and nitro-cumarin 
 (B. 35, 1153 ; 37, 4497). See also Acetyl-oxy-cumarin. 
 
 Allyl-benzoyl- acetic ester C 6 H 5 .CO.CH/ 2C *** 5 melts at 
 
 \L/rl 2 .Url : Ul<> 
 
 122 (B. 16, 2132). 
 
 y-Phenyl-a-acetyl-erotonie lactone C 6 H 5 C : CH.CH(COCH 3 )COO, 
 m.p. 113, from aceto-phenone-aceto-acetic ester on boiling with 
 alcoholic KOH (B. 39, 1809). 
 
 IT. Phenyl-olefin- and diolefm-y-ketone-carboxylic Acids result by 
 the condensation (i) of aldehydes and ketone-carboxylic acids with 
 acids or alkalies ; (2) of olefm-dicarboxylic anhydrides e.g. male'ic- 
 acid anhydride, citraconic anhydride, and benzols with aluminium 
 chloride. 
 
 j8-Benzoyl-aerylic acid C 6 H 5 .CO.CH : CH.CO 2 H melts at 96 when 
 anhydrous. It results from the action of sulphuric acid upon maleic 
 anhydride (see above), as well as from phenyl-y-keto-a-oxy-butyric 
 acid. Also from bromo-benzoyl-propionic acid with potassium acetate, 
 and from phenyl-iso-crotonic acid with sodium hypo-iodide (C. 1908, I. 
 1175 ; 1909, I. 530). 
 
 Trichloro-ethylidene-aceto-phenone C 6 H 5 .CO.CH : CH.CC1 3 , melting 
 at 102, is produced when sulphuric acid acts upon chloral-aceto- 
 phenone. jS-Benzoyl-crotonicacidC 6 H 5 .CO.C(CH 3 ) : CH.CO 2 H, melting 
 at 113, is obtained from citraconic anhydride (B. 15, 891). 
 
 /r"O PT-T 
 
 jS-Benzal-laevulinic acid C 6 H 5 .CH : <\jj^ R , melting at 125, 
 
 is produced by the condensation of benzaldehyde and laevulinic acid in 
 acid solution. It parts with water upon distillation and forms 3-aceto- 
 i-naphthol. Phenyl-itaconic acid is formed by its oxidation, and 
 j8-benzyl-laevulinic acid by its reduction. Hydroxylamine produces 
 
 the neutral lactoxime, benzal-lcevoxime C 6 H 5 .CH : c<^ HzC<: melting 
 
 CH 3 / C : K0 
 at 94. 
 
PHENYL-OLEFIN- AND DIOLEFIN-CARBOXYLIC ACIDS 439 
 
 When benzaldehyde and laevulinic acid condense in alkaline solution 
 the product is : 
 
 S-Benzal-laevulmie acid C 6 H 5 CH : CH.CO.C 2 H 4 .CO 2 H, melting at 
 120. It yields benzal-angelic lactone, melting at 90 (B. 24, 3202), upon 
 distillation. 
 
 8-Cinnamal- laevulinic acid C 6 H 5 CH : CH.CH : CH.CO.CH 2 .CH 2 . 
 CO 2 H, m.p. 161, sulphur-yellow crystals, from cinnamic aldehyde, 
 laevulinic acid, and pyridin (B. 38, 1113). 
 
 12, 13. Phenyl-olefin- and diolefin-dicarboxylic Acids. Benzal- 
 malonie acid C 6 H 5 .CH : C(CO 2 H) 2 , melts with production of cinnamic 
 acid and allo-cinnamic acid. It is formed in the condensation of benzal- 
 dehyde, malonic acid, and glacial acetic acid. By heating a mixture 
 of benzylidene-aniline, and similar bodies, with malonic acid, cinnamic 
 acid is obtained at once (B. 31, 2596). Its ethyl ester, boiling at 198 
 (13 mm.), is obtained from benzaldehyde, malonic ester, and hydro- 
 chloric acid. It adds to itself more readily than the free acid. Aniline 
 as well as phenyl-hydrazin converts the methyl ester into j3-anilido- 
 and /2-phenyl-hydrazido-benzyl-malonie methyl ester, melting at 117 
 and 94 (B. 29, 813). When substituted benzaldehydes are used, sub- 
 stituted benzal-malonic acids result e.g. nitro-benzal-malonie acid, 
 which is reduced by ferrous sulphate and ammonia to j8-carbo-styril- 
 carboxylic acid (B. 21, R. 253). 
 
 a - Cyano - cinnamic acid, semi - nitrile of benzal - malonic acid 
 
 C 6 H 5 .CH : <X^ 2H , melting at 180, is obtained by the action of 
 
 cyano-acetic acid in the heat upon benzaldehyde, or when it is boiled 
 with cyano-acetyl chloride. When heated it passes into the nitrile of 
 cinnamic acid. The methyl and ethyl esters melt at 70 and 50. A 
 large number of semi-nitriles of unsaturated, aromatic malonic acids 
 of related constitution have been obtained by the union of readily ac- 
 cessible, aromatic aldehydes with cyano-acetic acid (B. 27, R. 262). 
 Nitrile~acid amide, dinitrile, and diamide of benzal-malonic acid, melt- 
 ing at 123, 87, and 190, have also been synthesised by the conden- 
 sation of benzaldehyde with cyano-acetamide, malonitrile, and malon- 
 amide (B. 28, 2251 ; 35, 1320). 
 
 Benzal-barbituric acid C 6 H 5 .CH : c^coNH/" 00 is easil > T formed 
 from benzaldehyde and malonyl-urea (B. 34, 1340). 
 
 f[i]CH:C.CO 2 H 
 j8-Carbo-styrii-a-carboxylic acid C 6 HJ is formed 
 
 ( [2]NH . CO 
 
 from o-amido-benzaldehyde upon heating it with malonic acid to 120, 
 and also from o-nitro-benzal-malonic acid (B. 21, R. 353). Its silver 
 salt, when heated, yields carbo-styril. 
 
 f[i]CH:C.C0 2 H 
 Cumarin-a-earboxylic acid C 6 HJ , melting at 187, 
 
 l[2]O CO 
 
 breaks down at 290 into carbon dioxide and cumarin. It is obtained 
 from salicyl-aldehyde, malonic acid, and glacial acetic acid or amine 
 bases (B. 31, 2593, 2597), as well as from 
 
 f[i]CH:C.CN 
 a-Cyano-eumarin C 6 H 4 4 melting at 182. This latter 
 
 ([2]O CO 
 
 body may be prepared by the action of dilute sulphuric acid upon 
 
440 ORGANIC CHEMISTRY 
 
 o-oxy-benzal-dicyano-aeetic ester HO[2]C 6 H 4 CH[CH(CN)CO 2 C 2 H 5 ] 2 + 
 JH 2 O, melting at 140. This is a condensation product of salicyl- 
 aldehyde and cyano-acetic ester (B. 27, R. 576). 
 
 a-Cumarin-carboxylie amide, m.p. 269. Anilide, m.p. 250 (C. 1906, 
 II. 724). Cp. also j8-0xy-eumarin-a-carboxylic ester. 
 
 Cinnamylidene - malonic acid, phenyl-butadiene-dicarboxylic acid 
 C 6 H 5 .CH : CH.CH : C(COOH) 2 , m.p. 208, has a yellow colour, but, on 
 illumination, it passes into a colourless, dimeric modification which 
 on oxidation yields a-truxillic acid, and therefore probably also 
 contains the tetramethylene ring. Concentrated sulphuric acid restores 
 the yellow, monomolecular form (B. 35, 2411 ; C. 1902, II. 1047). On 
 heating, cinnamylidene-malonic acid splits off CO 2 and gives a mixture 
 of linkage-isomeric forms of cinnamylidene-acetic acid. Methyl and 
 ethyl ester, m.p. 67 and 36. Reduced with Na amalgam, the acid gives 
 i, 4-hydro-cinnamylidene-malonic acid C 6 H 5 CH 2 CH : CH.CH (COOH) 2 , 
 m.p. 107 with decomposition, which, on heating with NaHO, passes 
 into the isomeric 3, 4-hydro-cinnamylidene-malonic acid C 6 H 5 CH 2 CH 2 
 CH:C(COOH) 2 , m.p. 116 with decomposition (A. 306, 259). Cin- 
 namylidene-cyano-aceticacidC 6 H 5 .CH : CH.CH : C(CN)CO 2 H,m.p.2i2. 
 
 Piperonylene - malonic acid (CH 2 O 2 ) [3, 4]C 6 H 3 .CH : CH.CH : 
 C(CO 2 H) 2 melts at 205 with decomposition into CO 2 and piperic acid 
 (B. 28, 1190). Phenyl-allyl-malonie acid C 6 H 5 C(CH 2 .CH : CH 2 ) (COOH) 2 
 melts with decomposition at 145. Its ester is formed when allyl 
 iodide acts upon phenyl-malonic ester (B. 29, 2600). 
 
 CH.CO 2 H 
 
 Phenyl - maleic acid || ^changes below 100 into its 
 
 C 8 H 6 .C.CO 2 H 
 
 anhydride, melting at 119, which is produced when bromine and PBr 3 
 act upon phenyl-succinic acid, and the reaction product is treated with 
 water. Phenyl-malic acid is formed simultaneously (B. 23, R. 573). 
 
 Cumarin-jS-earboxylic acid c a H 4 {^ (COOH) : ^g, m.p. 180, is de- 
 composed into CO 2 and cumarin, during the dry distillation of its 
 silver salt ; its ethyl ester, m.p. 78, is formed from phenol, oxalic-acid 
 ester, and sulphuric acid (B. 34, 422) ; from resorcin, oxalic-acid ester, 
 and sodium alcoholate we obtain umbelliferone-jS-carboxylic acid, 
 
 resorcyl-male'inic lactone HO[ 4 ]C,H 3 <[^ J_, m.p. 248 (B. 34, 
 
 38i). 
 
 C,H 5 .CH : C.CO 2 H 
 Phenyl-itaconic acid , m.p. 172, is formed (i) 
 
 CH a .C0 2 H 
 
 from succinic ester, benzaldehyde, and sodium ethylate ; (2) from 
 phenyl-paraconic ester and sodium ethylate. When fused, particularly 
 under reduced pressure, it separates into water and its anhydride, melt- 
 ing at i63-i66, which, in every fusion, changes in a slight degree to 
 isomeric phenyl-citraconic anhydride, melting at 60. Water changes the 
 latter to phenyl-citraconic acid, melting at iO3-io6. If phenyl-citra- 
 conic acid in chloroform solution, to which a little bromine is added, be 
 exposed to sunlight, it becomes phenyl-mesaconic acid, melting at 212. 
 On boiling with NaHO these isomeric acids are partly transformed 
 
 C 6 H 5 CH 
 into a fourth isomeric acid, phenyl-aticonic acid || 
 
 HO 2 C.C.CH 2 COOH 
 
PHENYL-OLEFIN- AND DIOLEFIN-CARBOXYLIC ACIDS 441 
 
 m.p. i49-i5i, which is stereo-isomeric with phenyl-itaconic acid. 
 By the action of concentrated sulphuric acid it easily discards water 
 
 and passes into indone-acetic acid c 6 H 4 |^)c.CH 2 CO 2 H, the phenyl- 
 itaconic acid only furnishing the corresponding anhydride. From this 
 the a's-position of the phenyl and carboxyl in phenyl-aticonic acid 
 has been deduced (cp. Vol. I. and A. 304, 130 ; 305, 35 ; 330, 292 ; B. 
 41, 3983). 
 
 Cumarin-propionic acid CH 4 {^ H :H3)C 2H , m.p. 171, is 
 
 formed, together with o-oxy-phenyl-methyl-iso-crotonic acid, from 
 salicyl-aldehyde, sodium pyro-racemate, and acetic anhydride. It 
 passes into a-ethyl-cumarin when it is distilled (A. 255, 285). 
 
 Methyl-phenyl-itaeonie acid C 6 H 5 C(CHj)=C(CO ? H)CH 8 .CO 2 H melts 
 with decomposition at i6i-i63. It is obtained from succinic 
 ethyl ester, aceto-phenone, and sodium ethylate in ether. Its anhy- 
 dride melts at 114. This acid may, like phenyl-itaconic acid, be trans- 
 formed into several isomerides (B. 37, 1619). 
 
 Styril-succinie acid, cinnamenyl succinic acid C 6 H 5 CH : CH.CH 
 (COOH).CH 2 COOH, m.p. 173, is obtained by saponifying the 
 resultant product of the action of alcoholic potassium cyanide 
 upon cinnamylidene malonic ester (cp. phenyl-succinic acid, and 
 A. 306, 254). 
 
 Cinnamylidene-succinic acid, styril-itaconic acid, cinnamenyl-itaconic 
 acid C 6 H 5 CH : CH.CH : C(COOH)CH 2 COOH, m.p. 2i5-2i8 with 
 decomposition, from cinnamic aldehyde, succinic ester, and sodium 
 ethylate, is reduced by sodium amalgam to phenyl-ethylidene-pyro- 
 tartaric acid C 6 H 5 CH 2 CH : CHCH(COOH)CH 2 COOH, m.p. 112. This 
 latter acid transposes, on boiling with NaHO, to phenyl-ethyl-itaconic 
 acid C 6 H 5 CH 2 CH 2 CH : C(COOH).CH 2 COOH, m.p. 153 (B. 34, 2188 ; 
 cp. A. 331, 151). 
 
 Phenyl-glutaconic acid C 6 H 5 .C(CH 2 .COOH) : CH.COOH, m.p. 154, 
 has been obtained from the condensation product formed in the union 
 of phenyl-propiolic ester with sodium-malonic ester. Its ester, b.p. n 
 187, is converted by ammonia into y-phenyl-a, c^-dioxy-pyridin 
 (C. 1899, I. 1081 ; B. 27, R. 163 ; A. 370, 72). 
 
 Benzal-glutaric acid C 6 H 5 .CH : C(CO 2 H)CH 2 .CH 2 .COOH (A. 282, 
 338) melts at 177 (B. 31, 2004). 
 
 Benzyl-glutaconic ester C 6 H 5 .CH 2 .CH(COOH)CH : CH.COOH melts 
 at 145 (A. 222, 261). Its ethyl ester, boiling at 203 (10 mm.), when 
 treated with aqueous ammonia at 100, forms benzyl-dioxy-pyridin 
 (B. 26, R. 318). 
 
 Cinnamenyl-glutarie acid C 6 H 5 CH : CH.CH(CH 2 CO 2 H) 2 , m.p. 135, 
 is obtained from the condensation product of cinnamenyl-acrylic 
 ester and sodium-malonic ester, or by oxidation of cinnamenyl-dihydro- 
 resorcin with sodium hypochlorite (A. 345, 206). 
 
 14. Phenyl-olefin-tricarboxylic Acids. Phenyl-carboxy-aconitic ester 
 C 6 H 5 C(C0 2 C 2 H 5 ) 2 C(C0 2 C 2 H 5 ) : CHCO 2 C 2 H 5 and benzyl - earboxy - 
 aconitic ester from phenyl- and benzyl-malonic esters, with chloro- 
 fumaric ester (C. 1902, II. 888). 
 
 15. Phenyl -oxy- olefin - dicarboxylic A cids. Cinnamenyl-paraconic 
 
 acid C C H 5 CH : CH.dH.CH(CO 2 H)CH 2 .COO, m.p. 145, from cinnamic 
 
442 ORGANIC CHEMISTRY 
 
 aldehyde and succinic acid. On boiling with water it yields cinna- 
 menyl-crotonic acid (C. 1906, II. 515). 
 
 jS-Oxy-eumarin-a-earboxylie ethyl ester C 8 H 4 |C(QH) : CH.co a c,H^ 
 
 m.p. 101, is formed by the condensation of acetyl-salicylic-acid 
 chloride with sodium-malonic ester, and detachment of NaCl and 
 acetic ester. In a similar manner we obtain /?-oxy-a-eyano-cumarin, 
 m.p. 242, and jS-oxy-a-acetyl-cumarin, m.p. 134, from acetyl- 
 salicylic chloride and sodium cyano-acetic ester or aceto-acetic ester 
 (A. 367, 169). 
 
 16. Phenylene-oxy-olefin-dicarboxylic Acids. Phthalyl-acetic acid 
 and iso-cumarin-carboxylic acid have the same relation to each other 
 that methylene-phthalide sustains to iso-cumarin. Phthalyl-acetic 
 acid and its homologues have been obtained by applying the Perkin 
 reaction to phthalic anhydride : 
 
 J/~* _ C^T-T f~*(~\ TT 
 ------- ------------ 6 _ 5k melts with decomposition 
 
 (coo 
 
 above 260. When distilled under greatly diminished pressure it 
 breaks down into carbon dioxide and methylene-phthalide. Salts of 
 benzoyl-aceto-carboxylic acid are obtained by dissolving it in alkalies. 
 When it is heated with water to 200 it breaks down into carbon 
 dioxide and o-acetyl-benzoic acid. When heated with ammonia it 
 forms phthalimide-acetic acid. The alkylamines react analogously. 
 
 Sodium ethylate converts phthalyl-acetic acid into the sodium salt 
 of diketo-hydrindene-carboxylic acid (q.v.) (B. 26, 953). 
 
 f[i]CH=C CO 2 H 
 Iso-cumarin-carboxylic acid C 6 H 4 J , melting at 237, 
 
 ( [2]CO C 
 
 is formed when o-carbo-phenyl-glyceric-acid lactone is heated to 160 
 with hydrochloric acid ; see Iso-cumarin. Ammonia converts it quite 
 
 {[i]CH=CCO,H 
 ' , melt- 
 [2]CO NH 
 
 ing at 320 (B. 25, 1138). Boiling caustic potash decomposes it into 
 o-toluic acid and oxalic acid (B. 28, R. 770). 
 
 On the formation of y-oxy-iso-carbo-styril-carboxylic ester from 
 phthalyl-glycocollic ester, see the latter. 
 
 Oxy-methylene-homophthalic ethyl ester C 6 H 4 / C < : CHOH).co 2 c 2 H 6 a 
 
 UCO 2 C 2 H 5 
 
 colourless oil of strong acid reaction, obtained by the condensation of 
 homophthalic ester with formic ester. On heating to 100 it passes 
 into iso-eumarin-4-carboxylie ethyl ester c 6 H 4 / c ^ c 2C2H ^ :CH ) m .p. 
 
 V. C^U'" ' ------ ' " '" ---- '\J 
 
 68, which is split up again into formic acid and homophthalic acid by 
 alkalies. Ammonia converts the ester into iso-carbo-styril-4-ear- 
 boxylic ethyl ester C 6 H 4 {C(CQ 2 C 2 H 5 ) : CH^ m p ^ (R ^ ^^ 
 
 17. Phenylene - oxy - olefin - tricarboxylic A cids. Phthalyl-malonic 
 
 f[i]C=C(C0 2 C 2 H 5 ) 2 
 ester C H 4 J \ , melting at 74, is formed, together with 
 
 I [2] COO 
 phthalyl-dimalonic ester, from phthalyl chloride and sodium-malonic 
 
 f[i]C=C 
 ester (A. 242, 46). Phthalyl-cyano-acetic ester c e HJ 
 
 I [2]COO 
 
HYDRO-AROMATIC HYDROCARBONS 443 
 
 melting at 175, is made from phthalyl chloride and sodium-cyano-acetic 
 ester (B. 26, R. 370). 
 
 B. Hydro-aromatic Substances with Single-nucleus, Hydro-benzol 
 
 Derivatives. 
 
 It was shown in the introduction to the carbocyclic compounds that 
 the treatment of the hydro-aromatic derivatives presupposed a know- 
 ledge of the aromatic bodies. Indeed, numerous reactions which led 
 to the hydro-aromatic compounds, especially the additions, were 
 described in connection with the aromatic substances. Many bodies 
 discussed under the aromatic derivatives e.g. the quinones are 
 rather to be viewed as derived from the hydro-aromatic hydrocarbons. 
 And synthetic reactions were also studied in the discussion of the fatty 
 bodies which will again be encountered. 
 
 The methods of ring formation in cyclo-paraffins, discussed at the 
 commencement of this volume, are also used to some extent in the 
 building up of hydro-aromatic substances. The terpenes and camphor 
 will be included in the hydro-aromatic derivatives, as they are closely 
 related to the hydrated m- and p-cymols. 
 
 (i) HYDRO-AROMATIC HYDROCARBONS. 
 
 Hexahydro-benzol is the parent hydrocarbon of the hydro-aromatic 
 substances. Tetra- and dihydro-benzol bear the same relation to it 
 that an olefin and a diolefin show to the paraffin, having the same 
 number of carbon atoms. 
 
 The hexahydro-benzols, which are isomerides of olefins with a like 
 number of carbon atoms, resemble the paraffins in chemical behaviour ; 
 they belong to the cyclo-paraffins, while the tetrahydro-benzols belong 
 to the cyclo-olefins, the dihydro-benzols to the cyclo-diolefins, and 
 benzene is the simplest imaginable cyclo-triolefin, if we accept the 
 formula proposed for it by Aug. Kekule. 
 
 The aromatic compounds in general oppose a great resistance to 
 the attachment of hydrogen. This was only overcome in 1897 by an 
 excellent method discovered by Sabatier and Senderens, which con- 
 sists in conducting the vapours of aromatic substances, with excess of 
 hydrogen, over finely divided hot nickel. By this means it is easy to 
 convert aromatic hydrocarbons, phenols, and anilines into the corre- 
 sponding hydro-aromatic compounds. 
 
 Berthelot (1867) first effected the reduction of benzene to hexa- 
 hydro-benzol. It was obtained pure by Baeyer (1894) in the course of 
 an investigation in which he demonstrated how the simplest repre- 
 sentatives of the hydro-aromatic bodies hexahydro-benzol, tetrahydro- 
 benzol, and dihydro-benzol could be prepared from p-diketo-hexa- 
 methylene, a decomposition product of succino-succinic ester. Before 
 beginning a detailed description of the hydro-aromatic hydrocarbons, 
 it may be well briefly to present the steps of this research in a 
 diagram. The enclosed numbers following the names refer to the 
 formulae of the diagram. 
 
 p-Diketo-hexamethylene (i) yields quinite (2) by reduction, which 
 hydrogen bromide changes to p-dibromo-hexamethylene, and hydrogen 
 iodide into the mono-iodo-hydrin (4) of quinite, along with p-di-iodo- 
 
444 ORGANIC CHEMISTRY 
 
 hexamethylene. Quinite mono-iodo-hydrin, when reduced, yields oxy- 
 hexamethylene (5), obtained more easily from pimelin-ketone and 
 cyclo-hexanone. Hydrogen bromide and iodide convert oxy-hexa- 
 methylene (6) into bromo- and iodo-hexamethylene (6, 7). When p-di- 
 bromo-hexamethylene and monobromo-hexamethylene are heated with 
 quinolin, the latter yields tetrahydro-benzol (8) and the former dihydro- 
 benzol (9) ; whereas mono-iodo-hexamethylene is reduced by zinc dust 
 and glacial acetic acid to hexahydro-benzol (10) : 
 
 \CH..CH 
 
 (7) 
 
 CH /CH 2 .CH 2 \ 
 
 CHs XCH..CH, /C 
 
 The following values (V) and differences (D) were observed by 
 Stohmann in determining the heats of combustion and the boiling- 
 points of benzene, the three hydro-benzols, and hexane : 
 
 Approximately. 
 
 QH. (V) =779-8 | D=68 . 2Cal b.p.8o. 4 l D = + 5 
 
 C.H 8 =848-0 1 =44 . Q 8 4 -86* 
 
 C S H 10 =8 92 .o{ . 8 2 -8 4 J = _ 
 
 C 6 H 12 -993-2 {' 79 -79-5{ 
 
 C.H M =991 -2}" =58-c- M 69 o } = 
 
 The differences calculated from these numbers would have to be 
 equal if the changes were of like character. The magnitude of these 
 differences expresses, therefore, the magnitude of the changes involved 
 in the reduction (A. 278, 115). 
 
 (10) CYCLO-HEXANES, HEXAHYDRO- BENZOLS (NAPHTHENES). 
 
 Hydro-aromatic hydrocarbons constitute the chief portion of 
 Caucasian petroleum (I. 88) (Beilstein and Kurbatow, B. 13, 1818). 
 Markownikow has, therefore, designated them naphthenes. 
 
 The simplest naphthene, hexahydro-benzol, is also called hexa- 
 naphthene, and its homologues are called heptanaphthene, octo- 
 naphthene, nononaphthene, etc. Besides these hexahydra-benzols, we 
 also find in Caucasian petroleum the isomeric alkyl pentamethylenes 
 (cp. B. 31, 1803 ; Ch. Zeitung, 22, 900 ; A. 324, i). Hexahydro- 
 benzols have also been discovered in the tar from bituminous coal and 
 in that from certain shales, as well as in the resin oils obtained from the 
 distillation of colophonium. 
 
 Finally, a nononaphthene, hexahydro-pseudo-cumol, has been found 
 in coal-tar (C. 1908, II. 402). Artificially, the hexahydro-benzols are 
 prepared from their halogen substitution products by reduction, or 
 by transposition with alkyl-magnesium haloids. They are obtained 
 most easily by reduction of the benzene hydrocarbons, on passing the 
 latter, in the gaseous state, mixed with hydrogen, over finely divided 
 
CYCLO-HEXANES, HEXAHYDRO-BENZOLS 445 
 
 nickel at temperatures of 180 to 250. In the benzol homologues, 
 with lengthy side chains, this is accompanied by a partial breaking up 
 of the latter. Thus, from propyl-benzol we obtain, besides propyl- 
 cyclo-hexane, a small quantity of ethyl- and methyl-cyclo-hexane. At 
 temperatures above 300 the cyclo-hexanes are broken up by the 
 nickel, particularly in the hydrogen and the corresponding benzene 
 hydrocarbons (C. 1901, I. 502, 817 ; II. 201). They have been made 
 artificially by reducing aromatic hydrocarbons with hydriodic acid 
 at high temperatures. Hexahydro-benzol resists decomposition by 
 means of hydrogen very strongly (A. 278, 88). The hexahydro-benzols 
 are more easily obtained by reducing their halogen substitution 
 products. 
 
 When hydro-iodic acid is used as a reducing agent, under certain 
 circumstances alkyl-pentamethylenes appear to form by a process of 
 isomerisation ; these are isomeric with the hexamethylenes. Thus 
 methyl-pentamethylene is formed together with hexamethylene (B. 30, 
 1214; A. 324,6). 
 
 The hexahydro-benzols are distinguished from the olefins isomeric 
 with them by their higher specific gravity, and their inability to take 
 up bromine. Like the paraffins, they are first changed by chlorine or 
 bromine into monohalogen substitution products. 
 
 Heating with dilute nitric acid produces nitro-substitution products ; 
 tertiary H atoms are replaced by the NO 2 group with particular ease 
 (A. 30i, 154 ; 302, i ; C. 1899, I. 176 ; 1910, II. 1376). With nitro- 
 sulphuric acid small quantities of nitrified benzol hydrocarbons are 
 produced. The action of bromine and aluminium bromide converts 
 the hexahydro-benzols into substitution products of aromatic hydro- 
 carbons : 
 
 Cyclo-hexane, hexahydro-benzol . . m.p. 6-4 
 Methyl-cyclo-hexane, hexahydro-toluol 
 1, 1-Dimethyl-cyclo-hexane .... 
 1, 2-Dimethyl-cyclo-hexane, hexahydro-o-xylol . 
 1, 3-Dimethyl-cyclo-hexane, hexahydro-m-xylol . 
 1, 4-Dimethyl-cyclo-hexane, hexahydro-p-xylol . 
 Ethyl-cyclo-hexane .... 
 
 1, 2-Methyl-ethyl-cyclo-hexane 
 
 n-Propyl-cyclo-hexane .... 
 1, 3, 5-Trimethyl-cyclo-hexane, hexahydro-mesitylene 
 1, 3, 4-Trimethyl-cyclo-hexane, hexahydro-pseudo-cumol 
 1, 3, 5-Dimethyl-ethyl-cyclo-hexane 
 
 b.p. 81 D 20 0-7788 
 
 100 ,, 0-7697 
 
 120 D 15 0-7864 
 
 126 D 20 0-7733 
 
 ,, 121 0-7736 
 
 ,, I2O ,, 0-7690 
 
 I30 0-7772 
 
 I 5 I 0.784 5 
 
 156 0-7865 
 
 138 0-7867 
 
 143 0-7807 
 
 ,, 169 0-7929 
 
 1, 4-Methyl-iso-propyl-cyclo-hexane, hexahydro-cymol 167 seeTerpene. 
 
 Literature. x B. 34, 2799. 2 A. 341, 129. 3 C. 1905, II. 1673. 4 C. 1901, 
 II. 201. 5 C. 1909, I. 851. B. 34, 2035. '0.1899,1.176. 
 
 Of these hydrocarbons, cyclo-hexane (B. 28, 1234 > A. 302, 2), 
 methyl-, i, 3-dimethyl-, I, 3, 4-trimethyl-, and I, 3, 5-dimethyl-ethyl- 
 cyclo-hexane have been found in the naphtha of Caucasian petroleum, 
 while methyl-, propyl-, i, 3-dimethyl-, and i, 4-methyl-iso-propyl- 
 cyclo-hexane have been found in resin oil. Most of these have also 
 been prepared by reduction of the corresponding benzene derivatives 
 by the methods above named. 
 
 Cyclo - hexane, hexahydro - benzol, naphthene, hexamethylene 
 
446 ORGANIC CHEMISTRY 
 
 H 2 , results from the reduction of benzene or of 
 
 iodo-cyclo-hexane (see above) ; or by the action of sodium upon 
 synthetic hexamethylene bromide. Pure hexamethylene is a liquid 
 smelling like benzine. Heated with bromine to 150, it yields sym. 
 tetrabromo-benzol ; digesting with nitric acid oxidises it to adipinic 
 acid (A. 324, 3). 
 
 Methyl-cyclo-hexane, hexahydro-toluol, heptanaphthene, has also 
 been made from suberyl alcohol by the action of HI at 140 (B. 25, 
 R. 858), as well as from synthetic methyl-hexamethylene-ketone by 
 means of the corresponding alcohol (B. 29, 731). Bromine and alumi- 
 nium bromide convert it into pentabromo-toluol, melting at 282. 
 
 1, 3-Dimethyl-cyelo-hexane, hexahydro-m-xylol, octonaphthene, is 
 obtained from camphoric acid, from heptanaphthene-carboxylic acid 
 by means of HI (A. 225, no ; B. 24, 2718 ; 25, 920 ; C. 1905, I. 1392), 
 and from 2, 6-dimethyl-cyclo-hexanol ; this substance has been 
 obtained from optically active I, 3-dimethyl-cyclo-hexanol, in a feebly 
 dextro-rotatory form, [a] D =o-8 (B. 35, 2680). 1, 4-Dimethyl-eyclo- 
 hexane has been obtained synthetically from dimethyl-succinylo- 
 succinic ester (B. 31, 3206). 
 
 1, 3, 4-Trimethyl-cyclo-hexane, hexahydro - pseudo - cumol, nono- 
 naphthene, from 2, 3, 6-trimethyl-cyclo-hexanol (B. 29, 215) ; when 
 acted upon with bromine and aluminium bromide, it yields tribromo- 
 pseudo-cumol. 
 
 n-Propyl-eyclo-hexane has also been formed from chloro-cyclo- 
 hexane, propyl iodide, and zinc. 
 
 1, 3-Methyl-iso-propyl-cyclo-hexane, sym. menthane, b.p. 167, is 
 formed by the reduction of its iodine substitution product. 
 
 [1, 3]-Diethyl-cyelo-hexane, b.p. 170, sp. gr. 07957 (22), from 
 2, 6-diethyl-cyclo-hexanol. 
 
 Halogen Substitution Products of the Hexahydro-benzols. Forma- 
 tion : (i) From the hexahydro-benzols by the introduction of chlorine. 
 (2) By the addition of halogens and halogen hydrides to di- and tetra- 
 hydro-benzols. (3) By the addition of halogens to benzols and halogen 
 benzols. (4) From cyclo-hexanols through the exchange of hydroxyl 
 groups for halogens, by means of H haloids or P haloids. 
 
 The third method has brought to light some peculiar isomeric 
 phenomena. Two isomeric benzene hexachlorides, and two isomeric 
 chloro-benzol hexachlorides, have been found. The disposition on the 
 part of chemists is to ascribe the cause of this isomerism to the different 
 positions of the attached chlorine atoms with reference to the plane 
 of the carbon ring, as in the case of the isomeric trithio-aldehydes and 
 the isomeric tri-, tetra-, and pehtamethylene-dicarboxylic acids. 
 
 Of the dihalogen cyclo-hexanes and the monohalogen alkyl-cyclo- 
 hexanes, cis-trans- isomeric forms have also been discovered : 
 
 Chloro-cyclo-hexane . . b.p. 143 
 
 Bromo-cyclo-hexane . . 163 
 
 Iodo-cyclo-hexane . . b.p." 69 
 
 1, 1-Methyl-chloro-cyclo-hexane b.p. 40 54 
 
 1, 2-Methyl-chloro-cyclo-hexane b.p. 156 
 
 1, 3-Methyl-chloro-cyclo-hexane ,, 160 
 
 1, 4-Methyl-chloro-cyclo-hexane 158 
 
 Literature. 1 C. 1898, I. 1294. 2 C. 1905, II. 1429. 3 A. 302, xx ; B. 34, 2801. 4 C. 1905, I. 1242 ; 
 B. 40,2062. * A. 278, 94- 6 B. 40, 2067. ' B. 40, 4865. 
 
 1, 2-Dichloro-cyclo-hexane . b.p. 190 
 
 1, 2-Dibromo-cyclo-hexane . b.p. 100 146 
 
 1, 4-Dibromo-cyclo-hexane . m.p. 113 
 
 1, 4-Di-iodo-cyclo-hexane . 145 
 
 Hexahydro-benzyl chloride b.p. 100 98 
 
 Hexahydro-benzyl iodide b.p. 29 103 
 
CYCLO-HEXANES, HEXAHYDRO-BENZOLS 447 
 
 Various di-, tri-, and tetrachloro-cyclo-hexanes have been obtained, 
 besides monochloro-cyclo-hexane, by the chlorination of cyclo-hexane 
 at o. With KHO they yield cyclo-hexane, chloro-cyclo-hexane, 
 chloro-hexadiene, benzene, and chloro-benzol (C. 1903, II. 664). 
 
 The halogen derivatives of the cyclo-hexanes cannot, like the ali- 
 phatic halogen alkyls, be converted into the corresponding alcohols, 
 cyanides, mercaptans, etc., by transformation with alkali salts, and 
 other substances of basic reaction like KCN, KSH, Ag 2 O, NH 3 , 
 sodium-malonic ester, etc. Instead, they split off halogen hydride 
 and form tetra- or dihydro-benzols. On the other hand, the cyclo- 
 hexyl magnesium haloids are easily formed, and from these we may 
 obtain, with oxygen, cyclo-hexanols ; with CO 2 , the cyclo-hexane- 
 carboxylic acids ; with aldehydes and ketones, extra-cyclic alcohols. 
 
 a- or trans-Benzene hexachloride C 6 H 6 C1 6 , melting at 157 and boil- 
 ing at 218 (345 mm.), decomposes into 3HC1 and unsym. trichJoro- 
 benzol. - or cis-Benzene hexachloride melts and sublimes near 310. 
 a-Benzene hexachloride was made by the action of chlorine upon 
 benzene in sunlight (1825, Faraday ; 1835, Mitscherlich, Pogg. A. 35, 
 370). a- and ft- Benzene hexachloride s are produced when chlorine is 
 conducted into boiling benzene (1884, Meunier ; B. 18, R. 149 ; 19, R. 
 348), or, better, into a mixture of benzene and I per cent, sodium 
 hydroxide. The a-body is separated by distillation in steam from the 
 less volatile jS-derivative (B. 24, R. 632), or by means of chloroform 
 from the more sparingly soluble /2-compound. The latter is the more 
 resistant of the two modifications. When heated with alcoholic 
 potash it is converted with greater difficulty than the a-body into 
 unsym. trichloro-benzol. It is not affected by alcoholic potassium 
 cyanide, but, when boiled with this reagent, the a-variety is converted 
 into unsym. trichloro-benzol. Zinc in alcoholic solution changes the 
 a-modification into benzene (Z. f. Ch. 1871, N.F. 7, 284, 293). 
 
 a- and j8- Chloro-benzol hexachloride C 6 H 5 C1 7 , melting at 146 and 
 260, yield I, 2, 3, 5-tetrachloro-benzol with alcoholic potash (A. 141, 
 101 ; B. 25, 373). 1, 2, 4-Trichloro-benzol hexachloride C 6 H 3 C1 9 melts 
 at 95. 
 
 o-Xylol hexachloride C 6 H 4 (CH 3 ) 2 C1 6 , m.p. 194, b.p. 26o-265 
 (C. 1898, I. 1019). 
 
 a-Benzene hexabromide C 6 H 6 Br 6 , melting at 212, results from the 
 action of bromine upon benzene in sunlight, and when bromine acts 
 upon boiling benzene. When it splits off HBr, i, 2, 4-tribromo-benzol 
 is formed (Pogg, A. 35, 374). It is isomorphic with a-benzene hexa- 
 chloride (B. 18, R. 553). 
 
 (ib) CYCLO-HEXENES, TETRAHYDRO-BENZOLS, NAPHTHYLENES. 
 
 Tetrahydro-toluol has been found together with hexahydro-toluols 
 and allied hydrocarbons in the essence of resin. 
 
 Cyclo-hexenes are produced artificially (i) from the halogen cyclo- 
 hexanes by withdrawing the hydrogen haloid by means of alkali or 
 tertiary amines, especially quinolin. (2) From amido-cyclo-hexanes, 
 by dry distillation of their chlorohydrates or phosphates. (3) From 
 the cyclo-hexanols by extracting water by means of SO 4 HK, P 2 O 5 , 
 ZnQ 2 , A1C1 3 , or by heating with aqueous oxalic acid (B. 34, 3249), 
 
448 ORGANIC CHEMISTRY 
 
 or phthalic anhydride. In order to avoid possible transpositions 
 during the extraction of water from cyclo-hexanols, these are trans- 
 formed by the action of CS 2 upon their sodium or potassium salts, and 
 by methylation of the resulting xanthogenates into the corresponding 
 xanthogenic methyl esters, which, on distillation at ordinary pressure, 
 decompose into COS, mercaptan, and the corresponding cyclo-hexene : 
 
 - C w H aw _ 2 +COS+CH 8 SH. 
 
 This method is particularly suitable for the higher molecular 
 alcohols, and has been very serviceable for preparing terpenes. Those 
 alkylidene-cyclo-hexanes which contain a semi-cyclic linkage are iso- 
 meric with alkyl-cyclo-hexenes (compare ethylidene-cyclo-hexane, etc.). 
 These hydrocarbons, which are of special importance in the chemistry 
 of terpenes, are generated by discarding CO 2 from the cyclo-hexene 
 and cyclo-hexylidene fatty acids obtained by condensation of cyclo- 
 hexanones with bromo-aliphatic esters and zinc, with dehydration. 
 They differ from the isomeric cyclo-hexenes, with unsaturated rings, 
 by their higher specific gravities, higher boiling-points, and abnormal 
 molecular refraction (A. 360, 36). On heating with alcoholic sulphuric 
 acid, they easily shift the double linkage and become true tetrahydro- 
 benzols. A similar capacity for transposing into hydrocarbons of the 
 same linkage, especially under the influence of acids, is shown, to some 
 extent, by all alkyl-cyclo-hexenes, so that the preparation of a perfectly 
 uniform hydrocarbon, apart from cyclo-hexene itself, has probably 
 not yet been accomplished. Characteristic of the cyclo-hexenes are 
 their addition products with NOC1, N 2 O 3 and N 2 O 4 , the so-called 
 nitroso-chlorides, nitrosites, and nitrosates (compare terpenes). 
 
 Cyclo-hexene, tetrahydro-benzol CH 2 / 2 OF VH, boiling at 82- 
 
 \Uxj.2 - txttj/ 
 
 84, is produced on distilling monobromo- and monochloro-cyclo- 
 hexane with quinolin or alcoholic potash (A. 302, 27), and from cyclo- 
 hexanol by heating with oxalic acid (B. 34, 3252) or HKSO 4 (C. 1905, 
 I. 1014). It is a colourless liquid, resembling petroleum. It has less 
 of the leek odour than dihydro-benzol. It is coloured yellow by con- 
 centrated sulphuric acid. 
 
 With ozone it yields a very stable ozonide C 6 H 10 O 3 , which can be 
 recrystallised from alcohol, m.p. 75. Water decomposes this, with 
 formation of adipin-dialdehyde and adipinic acid (B. 42, 694). The 
 nitroso-chloride melts at 152. The nitrosate NO.C 6 H 10 .O.NO 2 melts at 
 150 with decomposition (A. 343, 49). 
 
 Methyl-cyelo-hexenes, tetrahydro-toluols C 6 H 9 .CH 3 . Three methyl- 
 cyclo-hexenes are possible, isomeric by the position of the double 
 linkage. The most stable of these is 
 
 AMHethyl-cyelo-hexene * CH z c(^^\cu 2 , b.p. io6-io8, 
 
 D 17 0-799. The isomeric hydrocarbons easily pass into this substance. 
 with displacement of the double linkage. It is formed, nearly pure, 
 
 * A 1 , A 2 , A 3 , etc. indicates the situation of a double linkage of the C-atom 
 i, 2, 3, etc. reckoned with reference to the next higher number. It is sometimes 
 preferable to affix the number indicating the double linkage to the name, e.g. 
 " methyl-cyclo-hexene-i." The same notation is sometimes used to indicate the 
 position of the hydroxyl or keto-group in the alcohols and ketones, e.g. " i-methyl- 
 cyclo-hexanone-3 . ' ' 
 
CYCLO-HEXENES, TETRAHYDRO-BENZOLS 449 
 
 from i, I- and I, 2-methyl-cyclo-hexanol. It is formed, practically 
 pure, from i, i- and i, 2-methyl-cyclo-hexanol by elimination of water 
 (see also A. 359, 287). An apparently fairly uniform A 3 -methyl-eyclo- 
 hexene, b.p. 103, D 15 0-841, [a] D +no, has been obtained by heating 
 acid phthalic ester, or the methyl-xanthogenate of the optically active 
 i, 3-methyl-cyclo-hexanol . On oxidation with KMnO 4 , it yields j3- 
 methyl-adipinic acid (C. 1904, 1. 1346, 1213). A 2 -Methyl-cyelo-hexene, 
 b.p. 103, D 27 07937, [a] D -f 81-47, from i, 3-methyl-iodo-cyclo-hexane 
 (B. 34, 3252 ; 35, 2493). 
 
 Synthetically, a methyl-cyclo-hexene has been obtained from 
 perseite (Vol. I.) by heating with HI (B. 25, R. 503). 
 
 Isomeric with the tetrahydro-toluols is methene-cyclo-hexane 
 CH 2 :C<^ 2 ^ 2 ^>CH 2 , b.p. 106, D 20 0-8020, n D =i-45i6, from cyclo- 
 
 hexene-actic acid, and from hexahydro-benzyl iodide, with alcoholic 
 potash (A. 359, 291 ; B. 40, 4863). It yields, on oxidation with 
 KMnO 4 , besides cyclo-hexanone, a glycol C 7 H 12 (OH) 2 , m.p. 77, which, 
 on heating with dilute H 2 SO 4 , passes into hexahydro-benzaldehyde. 
 On boiling with alcoholic sulphuric acid, it is transposed into A^methyl- 
 cyclo-hexene. Nitrole-piperidide, m.p. 127. 
 
 Several homologous tetrahydro-benzols have been obtained, mostly 
 by elimination of water from the corresponding cyclo-hexanols. As 
 regards their uniformity the above remarks apply. 
 
 1, 2-Dimethyl-cyelo-hexerie, b.p. 132, is formed from the 2, 2-di- 
 methyl-cyclo-hexanol, by dehydration and migration of a methyl 
 group (reversal of the pinacolin transposition, see Vol. I.) ; it easily 
 yields crystalline dibromide melting at about 138 (private communi- 
 cation of H. Meerwein). 1, 3-Dimethyl-cyclo-hexene, b.p. 124. 1,4- 
 Dimethyl-cyclo-hexene-l (B. 41, 2632). 1, 1-Dimethyl-cyelo-hexene, 
 b.p. 117, from dimethyl-dihydro-resorcin, yields, on oxidation by 
 KMnO 4 , a mixture of a, a- and j8, j3-dimethyl-adipinic acid (C. 1907, 
 I. 239). A^ethyl-, propyl-, and iso-propyl-cyclo-hexenes boil at 135, 
 155, and 156 respectively ; they are formed by linkage displacements 
 from ethylidene-, propylidene-, and iso-propylidene-eyclo-hexane, b.p. 
 138, 158, and 161 (A. 360, 44). Allyl-eycio-hexane C 6 H U .CH 2 .CH : 
 CH 2 , b.p. 149, from cyclo-hexyl-magnesium bromide and allyl bromide 
 (C. 1910, II. 387). a-Cyelo-geraniolene, i, 3, $-trimethyl-cydo-hexene-s 
 
 ^CHCH^CH 02 ' b ' p ' I 39- I 4i J is formed, besides the isomeric 
 j3-cyclo-geraniolene, from the olefinic terpene geraniolene by treating 
 with sulphuric acid. It is also formed from the synthetic dimethyl- 
 heptinol (CH 3 ) 2 C(OH).CH 2 .CH 2 .CH : C(CH 3 ) 2 by boiling with phosphoric 
 acid (B. 37, 848), and by the action of zinc chloride upon dihydro- 
 iso-aceto-phorol or 3, 5, 5-trimethyl-cyclo-hexanols, it yields a sparsely 
 soluble nitroso-chloride and nitrosate (A. 324, 97, 112). 
 
 Special interest attaches to A 1 - and A 3 -i, 4-methyl-iso-propyl-cyclo- 
 hexene, the so-called carro-menthene and menthene, which are closely re- 
 lated to the terpenes, and are therefore treated among hydro-terpenes. 
 
 (ic) DlHYDRO-BENZOLS [CYCLO-HEXADIENES], 
 
 Very probably some of the naturally occurring terpenes belong to the 
 dihydro-benzols. The artificially prepared representatives of the di- 
 VOL. II. 2 G 
 
450 ORGANIC CHEMISTRY 
 
 hydro-benzols are very similar in behaviour to them. The method of 
 preparing the simplest of the hydrocarbons in this class dihydro- 
 benzol from succino-succinic ester has already been discussed. Mono- 
 alkyl and di-p-alkyl-dihydro-benzols were made in like manner from 
 mono- and di-alkyl-succino-succinic esters (B. 26, 232). 
 
 The other methods of preparing dihydro-benzols are quite analogous 
 to this for cyclo-hexenes. They are formed (i) from the cyclo-hexane 
 diols which are obtained mostly by reduction of the easily synthesised 
 dihydro-resorcins as well as from cyclo-hexenols by dehydration ; (2) 
 from the dibromides of the cyclo-hexenes by heating with quinolin 
 (compare B. 42, 693) ; (3) by distillation of the phosphates of diamido- 
 cyclo-hexanes in a stream of CO 2 , if necessary under diminished 
 pressure (A. 328, 88 ; C. 1909, II. 356). 
 
 The dihydro-benzols mostly have a penetrating odour like that of 
 leeks. They are easily polymerised and resinified. With alcoholic 
 sulphuric acid and aceto-anhydride and sulphuric acid, they give char- 
 acteristic red or purple colours. By oxidising agents they can usually 
 be easily transformed into benzene derivatives. 
 
 The situation of the double linkages, and especially their uniformity, 
 is in most cases more doubtful in the dihydro-benzols than it is even 
 in the tetrahydro-benzols. The physical data communicated there- 
 fore only apply to a mixture of hydrocarbons which, according to its 
 transformations, consists mostly of the cyclo-hexadiene in question. 
 On the utilisation of molecular refraction for determining the con- 
 stitution of dihydro-benzols, see B. 43, 3076. 
 
 A 1 ' 3 - Cyclo-hexadiene, dihydro-benzol CH \H~CH / CH - b -P- 8l '5> 
 from i, 3-diamido-hexamethylene phosphate by distillation, from 
 i, 3-dichloro- and i, 2-dibromo-cyclo-hexane by heating with quinolin 
 besides some cyclo-hexene and small quantities of the isomeric A 1 ' 4 - 
 
 dihydro-benzol CH \cH~ZcH 2 !) CH ' b ' p> 8l ' 5 ' which is the chief P roduct 
 formed from i, 4-diamido-cyclo-hexane. The i, 4-cyclo-hexadiene 
 easily yields a tetrabromide, m.p. 188, whereas the i, 3-cyclo-hexadiene 
 yields chiefly a dibromide, m.p. 109, probably i, 4-dibromo-A 2 -cyclo- 
 hexene, which, on heating with quinolin, becomes benzene. The 
 dihydro-benzol formed from i, 4-dibromo-hexamethylene is a mixture 
 of both isomers (A. 328, 105 ; B. 41, 2479 ; 42, 693 ; C. 1904, II. 1736). 
 
 A^-Dihydro-toluol C ? H 7 .CH 3 , b.p. 111, from m-diamido-hexahydro- 
 toluol phosphate, on oxidation with KMnO 4 gives methyl-dioxy-hexa- 
 methylene-ketone or methyl-cyclo-hexanone-diol, and then succinic 
 and oxalic acids, which determine its constitution. But this hydro- 
 carbon also lacks uniformity (B. 41, 1698). A a ' 4 -Dihydro-toluol, b.p. 
 106, D 20 0-8274 (B. 41, 2484). A 2 > 6 -Dihydro-toluol, b.p. 109, D 20 
 0-8292 (B. 41, 2630). 
 
 1, 1-Dimethyl-cyclo-hexadiene (see B. 36, 2692 ; C. 1909, II. 356). 
 
 Dihydro-o-xylol, cantharene, b.p. 135, is produced when cantharic 
 acid C 10 H 12 O4, a rearrangement product of cantharidin, is distilled 
 with caustic lime. Its odour is like that of a terpene, and it resinifies 
 on exposure to the air (Piccard, 1878 ; B. 25, 2453 ; A. 328, 115). 
 
 A 3 ' 5 -Dihydro-m-xylol, b.p. 129, D 18 0-8203, from 3, 5-diamido- 
 1, 3-dimethyl-cyclo-hexane and from 1, 3-dimethyl-5-chloro-eyelo- 
 
RING-ALCOHOLS OF HYDRO-AROMATIC CARBONS 451 
 
 hexadiene-3, 5, the product of the action of PC1 5 upon i, 3-dimethyl- 
 cyclo-hexenone, by reduction (B. 43, 3111). 
 
 A 2 , 4 -Dihydro-m-xylol, b.p. 129, D 20 0-8225 (see B. 41, 2631). A 
 mixture of hydrocarbons containing a dihydro-m-xylol, besides m- 
 xylol and tetrahydro-m-xylol, has been obtained from methyl- 
 heptenone (CH 3 ) 2 C : CH.CH 2 .CH 2 COCH 3 by condensation with ZnCl 2 
 (C. 1909, II. 357)- 
 
 A 1 3 -Dihydro-p-xylol, b.p. I35-I38, D 19 0-8314, has been obtained 
 by a peculiar reaction on boiling dichloro-a, j3-pulenenone with alcoholic 
 potash ; it polymerises easily. Oxidation with KMnO 4 produces 
 acetyl-acetone, which proves its constitution (B. 41, 1816 ; 42, 2404). 
 A 2 ' 4 -Dihydro-p-xylol, b.p. 133 (B. 41, 2633). Dihydro-p-diethyl- 
 benzol, b.p. i8o-i85. 
 
 Addendum : Cyclo-hexyl-acetylenes. While steric conditions mili- 
 tate against the possibility, or at least the stability, of combinations of 
 cyclo-hexane with an acetylene binding in the nucleus, as well as of 
 combinations with two double linkages in the allene position, cyclo- 
 hexyl-acetylenes with the acetylene binding in the side chain have 
 been obtained by the methods usual in aliphatic series. 
 
 Cyelo-hexyl-acetylene C 6 H n C ; CH, b.p. 131, from cyclo-hexyl- 
 chlor-ethylene with KHO ; it gives a Na salt, which with CO 2 forms 
 hexahydro-phenyl-propiolic acid (C. 1909, II. 2081). Cyclo-hexyl- 
 allylene C 6 H n CH 2 .C CH, b.p. i65-i7o (see C. 1910, II. 387). 
 
 (20) RING-ALCOHOLS OF THE HYDRO-AROMATIC CARBONS. 
 
 In this group are included quercite and inosite, formerly classed 
 with the sugars, as well as the ring-alcohols of the terpane or men thane 
 group among the terpenes, while other members have been obtained 
 by the reduction of aromatic or hydro-aromatic compounds, but chiefly 
 from the corresponding ketones, which yield, by reduction, secondary 
 ring-alcohols, and, by transformation with magnesium-alky 1-iodides 
 (Vol. I.), tertiary ring-alcohols (B. 34, 2877 ; Ann. Chim. Phys., 8, 10, 
 527). Cyclo-hexanols have also been obtained by the action of oxygen 
 upon cyclo-hexyl-magnesium haloids, from the ring amines with HNO 2 , 
 by the attachment of water to cyclo-hexenes, by heating with glacial 
 acetic acid and concentrated H 2 SO 4 . Many alkyl-cyclo-hexanols 
 occur in stereo-isomeric forms. 
 
 Name. 
 
 M. P . 
 
 B.p. 
 
 D. 
 
 
 Cyclo-hexanol 
 
 15 
 
 160 
 
 0-9471 (22) 
 
 
 1-Methyl-cyclo-hexanol 
 
 13 
 
 157 
 
 0-9387 (12) 
 
 ( B. 34, 2880 
 \C. 1904, II. 219 
 
 2-Methyl-cyclo-hexanol 
 
 
 165 
 
 0-936 (14) 
 
 C. 1909, I. 850 
 
 3-Methyl-cyclo-hexanol 
 4-Methyl-cyclo-hexanol 
 
 
 
 172* 
 174 
 
 0-926 (12) 
 0-924 (14) 
 
 |c. 1905, I. 742 
 
 1-Ethyl-cyclo-hexanol 
 1, 2-Dimethyl-cyclo-hexanol 
 
 33 
 
 z66 
 166 
 
 0-926 (14) 
 
 C. 1904, II. 219 
 C. 1905, II. 483 
 
 1, 3-Dimethyl-cycl>hexanol 
 1, 4-Dimethyl-cyclo-hexanol 
 
 50' 
 
 169 
 170 
 
 0-9II (14) 
 
 C. 1907, I. 1606 
 C. 1906, I. 1096 
 
 2, 2-Dimethyl-cyclo-hexanol 
 2, 4-Dimethyl-cyclo-hexanol 
 2, 5-Dimethyl-cyclo-hexanol 
 
 6-5 
 
 63 (18 mm.) 
 179 
 
 0-9073 (16) 
 0-9073 (16) 
 
 j-C. 1906, I. 1248 
 
 2, 6-Dimethyl-cyclo-hexanol 
 3, 3-Dimethyl-cyclo-hexanol 
 3, 4-Dimethyl-cyclo-hexanol 
 3, 5-Dimethyl-cyclo-hexanol 
 
 12 
 
 174-5 
 78 (15 mm.) 
 189 
 187 
 
 0-9129 '15) 
 0-9119 (16) 
 0-9019 (16) 
 
 B. 28, 78i 
 C. 1907, I. 964 
 C. 1906, I. 1248 
 A. 297, 160 
 
452 ORGANIC CHEMISTRY 
 
 Cyelo-hexanol, hexahydro-phenol CH, 2 ~ ; 2 :HOH is formed 
 
 \v_/iri 2 v-/ x" 1 2 
 
 (i) from cyclo-hexanone by reduction with sodium and aqueous ether 
 (B. 34, 2800) ; (2) from p-iodo-hexahydro-phenol, the product of the 
 action of HI upon quinite, by reduction with zinc dust and glacial acetic 
 acid ; (3) from amido-hexamethylene and from pentamethylene- 
 methyl-amine with nitrous acid (A. 302, 20) ; (4) by passing gaseous 
 phenol and hydrogen over reduced nickel at about 170 (C. 1904, I. 454, 
 727 ; 1905, I. 1243) ; (5) by the action of oxygen upon cyclo-hexyl- 
 magnesium chloride (C. 1907, I. 1695). It smells like fusel-oil, and is 
 more soluble in water than the aliphatic alcohols with 6 C atoms (B. 
 26, 229). Its acetyl compound melts at 104. With HBr it forms a 
 bromo-cyclo-hexane. On oxidation with nitric acid (density 1-2), or 
 KMnO 4 , it gives a good yield of adipinic acid (for method of preparing 
 this acid, see B. 41, 575 ; C. 1908, 1. 1835). Cyclo-hexanol-methyl ether 
 C 6 H U OCH 3 , b.p. I35'5i from sodium-cyclo-hexanol and ICH 3 , or by 
 reduction of anisol with Irydrogen and nickel. For the ester of cyclo- 
 hexanol, see C. 1905, I. 1014. Cyclo-hexyl ether C 6 H n .O.C 6 H u , b.p. 
 276, from diphenyl ether with hydrogen and nickel (B. 41, 1001). 
 
 3-Methyl-eyelo-hexanol has also been obtained in its laevo-rotatory 
 form [a] D =-3 40' by reduction of the optically active 3-methyl-cyclo- 
 hexanone (B. 30, 1534). 
 
 1-Methyl-eyclo-hexanol is produced by nuclear synthesis in the 
 action of I, 5-magnesium-dibromo-pentane upon acetic ester (C. 1907, 
 II. 681). 
 
 3-Methyl-6-propyl, 3-methyl-6-iso-butyl-, and 3-methyl-6-iso-amyI- 
 cyclo-hexanol, b.p. 22 112, m.p. 69, and b.p. 23 137 respectively, are 
 obtained synthetically by heating 3-methyl-cyclo-hexanone with 
 sodium and propyl-iso-butyl- and iso-amyl-alcohol to about 220 (C. 
 1905, I. 872, noo). 3, 6, 6-Trimethyl-eyclo-hexanol, " pulenol," b.p. 
 188 (see A. 329, 87). 
 
 Hexahydro-thymol and hexahydro-earvaerol (see Menthol and Carvo- 
 menthol). 
 
 Polyvalent Ring-alcohols are produced (i) by reduction of poly- 
 keto-cyclo-hexanes ; (2) from polyvalent phenols, by reduction with 
 hydrogen and nickel (C. 1908, II. 240) ; (3) from cyclo-hexenes by 
 gentle oxidation with KMnO 4 , or by transformation of the correspond- 
 ing halogen hydrins. 
 
 trans- Cyclo-hexane-1, 2-diol, o-dioxy-hexahydro-benzol C 6 H 10 [i, 2] 
 (OH) 2 , m.p. 100, b.p. 225, is obtained from tetrahydro-benzol with 
 KMnO 4 (A. 302, 21) or by reduction of pyro-catechin. The isomeric 
 cis-i, 2-cyclo-hexane-diol, m.p. 104, b.p. 236, is produced from the 
 iodo-hydrin, o-iodo-cyclo-hexanol C 6 H 10 I(OH), m.p. 42, obtained from 
 cyclo-hexene with iodine and mercury, and yielding, with silver oxide 
 and KHO, at first a cyclo-hexene oxide C 6 H 10 > O, b.p. 131, resem- 
 bling ethylene oxide. This combines with water to form cis-cyclo- 
 hexane-diol, with bisulphite to cyclo-hexanol-sulphonic acid C 6 H 10 
 (OH)SO 3 H, with ammonia to o-amino-cyclo-hexanol C 6 H 10 [i, 2](NH 2 ) 
 (OH), m.p. 66, b.p. 219 (C. 1905, II. 1337). 
 
 i-Methyl-cyclo-hexane-i, 2-diol, m.p. 67, from A^methyl-cyclo- 
 hexene ; on heating with oxalic acid it yields i, 2-methyl-cyclo- 
 hexanone. 
 
RING-ALCOHOLS OF HYDRO-AROMATIC CARBONS 453 
 
 4-Methyl-eyclo-hexene-l, 2-oxide, b.p. 146, from the chloro hydrin 
 of A 3 -methyl-cyclo-hexene with KOH (A. 336, 310). 
 
 Gyclo-hexane-1, 3-diol, m.p. 65, by reduction of resorcin with H 
 and Ni at 130 (C. 1908, II. 240). 
 
 Quinite [Cyclo-hexane-i, 4-*diot] HOCH/^ 2 ~ ;2 a \:HOH, m.p. 
 
 NL-Hg Ori2/ 
 
 144, is formed from p-diketo-hexamethylene, when treated with 
 sodium amalgam, in the presence of carbon dioxide, or by reducing 
 hydroquinone with H and Ni. This was demonstrated by A. v. 
 Baeyer in 1892. It tastes sweet at first, then bitter, and is readily 
 soluble in water and in alcohol. Chromic acid oxidises it to quinone 
 (B. 25, 1038 ; 34, 506). Quinite serves for the preparation of the 
 simple hydride derivatives of benzene (B. 26, 229). Hydriodic acid 
 converts it into p-iodo-eyelo-hexanol and p-di-iodo-cyclo-hexane. By 
 reduction the first yields hexahydro-phenol, the second cyclo-hexane. 
 p-Dibromo-cye!o-hexane passes readily into dihydro-benzol (B. 26, 
 230). 2, 5-Dimethyl-quinite is formed from the corresponding di- 
 ketone (B. 25, 2122). 
 
 Phloro-glucite, s-trioxy-hexamethylene, cyelo-hexane-1, 3, 5-trioI 
 
 HOCH<^;** 2 ~" ;!?{J5\:H a +2H a O, me lts when anhydrous at 184. It 
 
 \Cri 2 CM (OH)/ 
 
 is formed when phloro-glucin is reduced in an approximately neutral 
 solution with sodium amalgam (B. 27, 357). 
 
 Cyelo-hexane-1, 2, 3-triol, a-form, m.p. 108 ; j8-forai, m.p. 124, 
 from A 2 -ethoxy-cyclo-hexene with KMnO 4 , and saponification of the 
 resulting ethoxy-cyclo-hexane-diol with concentrated HBr (C. 1910, 
 1. 2017). 
 
 Quercite, cyclo-hexane-pentol CH 2 <^|^|-|^j)cH(OH), m.p. 
 
 235, [a] D -f 24-16, occurs in acorns. The aqueous extract of 
 the latter can be freed of glucoses by fermentation with beer-yeast. 
 Also from the leaves of Chamfer ops humilis (C. 1908, 1. 267). Quercite 
 does not ferment with yeast. Hydriodic acid converts it into benzene, 
 hexane, phenol, quinone, and hydroquinone (Prunier). Nitric acid 
 oxidises it to mucic acid and trioxy-glutaric acid (see Vol. I.). A 
 solution of potassium permanganate converts it chiefly into malonic 
 acid, although oxalic acid and carbonic acid are formed simultaneously 
 (B. 29, 1762). A laevo-rotatory quercite, m.p. (anhydrous) 174, 
 [a] D = 73-9, has been discovered in the leaves of Gym-nemo, silvestre. 
 Penta-acetyl compound, m.p. 125 (C. 1904, II. 329). 
 
 Inosite, hexahydro-hexaoxy-benzol, cyclo-hexane-hexene C 6 H 6 (OH) 6 , 
 has seven possible optically inactive, and two optically active, modifi- 
 cations, as well as a racemic form (cp. Vol. I.). The only modifica- 
 tions known with certainty are one inactive and two active forms, and 
 the racemic form. 
 
 i-Inosite, phaseomannite, dambose C 6 H 6 (OH) 6 +2H 2 O, melts at 225 
 when anhydrous. It occurs in the muscles of the heart and in the urine 
 when there has been an excessive consumption of water ; also in 
 unripe beans (Phaseolus vulgaris) and peas. If heated to 170 with 
 hydriodic acid, it yields phenol, di-iodo-phenol, and traces of benzene 
 (Maquenne). Concentrated nitric acid oxidises it to di- and tetra- 
 oxy-quinones, and to rhodizonic acid (B. 20, R. 478 ; 23, R. 26 ; C. 
 1908, 1. 269). It yields furfurol on heating with P 2 O 5 (C. 1908, 1. 2152). 
 
454 ORGANIC CHEMISTRY 
 
 Dambonite C 6 H 6 (OH) 4 (OCH 8 ) 2 +3H 2 O is the dimethyl ether of 
 i-inosite. It occurs in the rubber from Gabon. i-Inosite hexa-acetate 
 melts at 211. 
 
 d-Inosite, melting at 247, [a] D =-f-65, from pinite by the action 
 of hydriodic acid, behaves like i-inosite with nitric acid. Pinite, mate- 
 zite CeH 6 (OH) 5 (OCH 3 ), melting at 186, [a] D =+65-5i, is present in 
 the juice of Pimts Lambertiana, also m the rubber from Mateza roritina 
 of Madagascar. 
 
 1-Inosite, melting at 238, [a] D = 55, from quebrachite by means 
 of hydriodic acid, behaves towards nitric acid just like i-inosite. 
 Quebrachite C 6 H 6 (OH) 5 OCH 3 , melting at 186, [a] D = 80, occurs in 
 the quebracho bark. Racemic inosite melts at 253. 
 
 Scyllite C 6 H 12 O 6 , m.p. about 340, probably a second inactive 
 inosite, was discovered by Staedeler in 1856. It is found in the organs 
 of various plagiostomes, e.g. Scyllium canicula, but most plentifully in 
 the kidneys of roach and pike (?), from which it is separated by means 
 of its slightly soluble lead salt (B. 40, 1821). 
 
 Gocosate C 6 H 12 O 6 , m.p. 345-350, from the leaves of Cocos nucifera 
 and Cocos plumosa, is very similar to inosite in its behaviour, and is 
 oxidised, like the latter, to rhodizonic acid by H 2 O 2 . The hexa-acetyl 
 compound melts about 300 (C. 1908, I. 267). 
 
 Phenose C 6 H 6 (OH 6 ) (?) is an amorphous, readily soluble substance, 
 deliquescing in the air. It has a sweet taste and reduces Fehling's 
 solution, but is not capable of fermentation. It has been obtained by 
 the action of a soda solution (A. 136, 323) upon the addition product 
 
 of benzene with three molecules of hypochlorous acid C 6 H 6 / / 2 
 (2b) RING ALCOHOLS OF TETRAHYDRO-BENZOL. 
 
 A 3 -Cyelo-hexanol, tetrahydro-phenol CH \^ ZCH^ H H ' b ' p< l63 ' 
 is formed when p-iodo-cyclo-hexanol is distilled with quinolin. 
 
 A 2 -Cyclo-hexanol-methyl and ethyl ether C 6 H 9 OAlk, b.p. 139 and 
 154 respectively, from the methyl and ethyl iodo-hydrins of cyclo- 
 hexane, the results of the action of iodine and HgO upon an alcoholic 
 solution of cyclo-hexene, by boiling with alcoholic potash. From the 
 corresponding dibromides we obtain, by saponification and reduction 
 
 with zinc dust and alcohol, A 2 -cyelo-hexenol CH 2 <^ X?\CHOH, 
 
 \utij C/HJ/ 
 
 b.p. 165 with decomposition. The urethane melts at 108 (C. 1905, 
 II. 1339) ; the A^cyclo-hexenol acetate, b.p. i8o-i82, is formed 
 by heating cyclo-hexanone with acetic anhydride and sodium acetate 
 (B. 41, 564). 
 
 Numerous A 2 -cyclo-hexenols have been obtained by reduction of 
 the 3-alkyl-A 2 -cyclo-hexenones, e.g. 3-methyl-A 2 -eyelo-hexenol, b.p. 
 176 (A. 289, i 3 f). 
 
 Dihydro-eumin alcohol C 9 H 13 .CH 2 OH, b.p. 5 93, has been found in 
 ginger grass and peppermint (?) oil (B. 44, 466). It is also produced 
 from a-phellandrene-glycol, on heating with dilute H 2 SO 4 . 
 
 (20) EXTRA-CYCLIC HYDRO-AROMATIC ALCOHOLS. 
 These have been obtained (i) by transformation of cyclo-hexyl- 
 magnesium haloids with aldehydes and ketones ; (2) from cyclo- 
 
RING-AMINES OF HYDRO-AROMATIC HYDROCARBONS 455 
 
 hexane-carbocyclic esters, and extra-cyclic hydro-aromatic ketones by 
 reduction, or by the action of alkyl-magnesium haloids ; (3) by oxida- 
 tion of alkylidene-cyclo-hexanes with dilute permanganate : 
 
 Cyclo-hexyl-carbinol . . . C,H U .CH,OH b.p. 181 D 0-944 ,C. 1904, II. 704. 
 
 Cyclo-hexyl-methyl-carbinol . . C.H n .CH(OH)CH, ,, 189 D 0-946 { C. 1907, 1. 1695- 
 
 Cyclo-hexyl-dimethyl-carbinol . . C.H n C(OH)(CH,) t b.p.,. 96 D 0-938 IB. 40, 4165. 
 
 /3-Cyclo-hexyl-ethyl-alcohol . . C,H U CH,.CH,OH b.p. 206 B. 41, 2628. 
 
 1-Methyl-cyclo-hexane-l, 7-diol C 6 H 10 (OH).CH 2 OH, m.p. 77, by 
 oxidation of methylene-cyclo-hexane with KMnO 4 ; with acids it 
 yields hexahydro-benzaldehydes (A. 347, 331). 
 
 1-Iso-propyl-cyclo-hexane-l, 7-diol C 6 H 10 (OH).C(OH)(CH 3 ) 2 , m.p. 
 83, from i, i-cyclo-hexanol-carboxylic ester and CH 3 MgI ; on heating 
 with dilute H 2 SO 4 it undergoes pinacolin transposition and yields 
 i-methyl-i-acetyl-cyclo-hexane (C. 1910, II. 466). 
 
 (zd) SULPHUR DERIVATIVES OF HYDRO-AROMATIC ALCOHOLS. 
 
 Cyclo-hexyl mercaptan, hexahydro-thio-phenol C 6 H n SH, b.p. 158- 
 1 60, a colourless, highly refractive oil of penetrating odour of mercap- 
 tan, is obtained in small quantities by transformation of halogen-cyclo- 
 hexanes with KSH ; and, more easily, by splitting up cyclo-hexyl- 
 xanthogenic ester C 6 H n S.CSOC 2 H 5 , b.p. ]6 152, with ammonia. It is 
 also prepared by the action of sulphur upon cyclo-hexyl-magnesium 
 chloride (C. 1910, I. 1830), or by reduction of cyclo-hexane-sulphonic 
 acid chloride, b.p. 15 127, with tin and HC1. It yields a sparingly 
 soluble mercury salt. Cyclo-hexyl-methyl sulphide C 6 H n S.CH 3 , b.p. 
 180, from the Na salt with ICH 3 . Dicyclo-hexyl disulphide (C 6 H n ) 2 S 2 , 
 b.p. 288, from the Na salt with iodine (B. 39, 392 ; 40, 2220). 
 
 (30) RING-AMINES OF HYDRO-AROMATIC HYDROCARBONS. 
 
 These are formed (i) by reduction of nitro-hexahydro-benzols with 
 zinc or tin and HC1, or of the oximes of the corresponding ketones 
 with sodium in alcoholic solution ; m-diamines, especially, have been 
 obtained by reducing the hydroxylamine oximes, the addition products 
 of hydroxylamine with cyclo-hexenone oximes ; (2) by reduction of 
 anilines with Ni and H (C. 1904, I. 884 ; B. 41, 991) ; (3) by heating 
 cyclo-hexanones with ammonium formate, or the formates of organic 
 bases (A. 343, 54) ; (4) from the cyclo-hexane-carboxylic amides by 
 decomposition with bromine and alkali (B. 40, 2061). 
 
 Amido-cyclo-hexane, cy do-he xylamine C 6 H U NH 2 , a strong base, 
 boiling at 134, smells of coniin ; but slightly soluble in water. It is 
 prepared from cyclo-hexanone oxime, or from the nitro-hexamethylene 
 C 6 H n NO 2 , b.p. 206. On conducting aniline vapour with hydrogen 
 over reduced nickel at 190, we obtain besides cyclo-hexyl-amine 
 cyclo-hexyl-aniline C 6 H U NHC 6 H 5 , b.p. 30 71, and dicyclo-hexyl- 
 amine (C 6 H n ) 2 NH, b.p. 30 145 (C. 1904, I. 884). Acetamido-eyelo- 
 hexane, m.p. 104. Its benzol compound melts at 147, and is also 
 obtained by transposition of a-hexahydro-benzo-phenone oxime (q.v.) 
 (B. 30, 2863). Phenyl-urea derivative, m.p. 180 ; phenyl-thio-urea 
 derivative, m.p. 147 (A. 302, 22). Cyclo-hexyl-methyl-, -ethyl-, and 
 -dimethyl-amine, b.p. 145, 164, and 165, are formed by hydrogenating 
 the alkyl-anilines with H and Ni (C. 1904, II. 105). 
 
456 ORGANIC CHEMISTRY . 
 
 1, 1-Amido-methyl-cyelo-hexane C 6 H 10 (CH 3 )NH 2 , b.p. 143, from 
 
 I, i-nitro-methyl-cyclo-hexane, b.p. 40 110, and by method 4 (C. 1910, 
 
 II. 1377). Benzoyl compound, m.p. 101. 
 
 1, 2-Amido-methyl-cyclo-hexane, b.p. 150 ; benzoyl compound, 
 m.p. 147. 
 
 1, 3-Amido-methyl-cyclo-hexane, b.p. 152 ; benzoyl compound, 
 m.p. 163, from methyl-cyclo-hexanone oxime, and from i, 3-nitro- 
 methyl-cyclo-hexane, b.p. ^ 120, by reduction, is converted into 
 methyl-cyelo-hexyl-hydrazin C 6 H 10 (CH 3 )NHNH 2 by treating its bromyl 
 compound with Ag 2 O (C. 1900, I. 653). 
 
 1, 4-Amido-methyl-cyclo-hexane, b.p. 151; benzoyl compound, 
 m.p. 181. 
 
 o-Diamido-cyelo-hexane C 6 H 10 [i, 2](NH 2 ) 2 is an oil, boiling at 183- 
 185. It results when the amide of hexahydro-anthranilic acid is 
 treated with sodium hypobromite and then with hydrochloric acid. 
 Like the aromatic o-diamines, it unites with benzaldehydes, forming 
 aldehy dines (A. 295, 187). 
 
 m-Diamido-cyclo-hexane, boiling at 193, smells like ethylene- 
 diamine. It is soluble in water. Nitrous acid decomposes it into 
 nitrogen and dihydro-benzol (A. 228,39). The diaceto-compound melts 
 at 256. 
 
 p-Diamido-cyclo-hexane C 6 H 10 [i, 4](NH 2 ) 2 is a liquid (B. 27, 1449). 
 
 m-Diamido-hexahydro-toluol C 6 H 9 [i, 3, 3](CH 3 )(NH 2 ) 2 , b.p. 17 85- 
 89, m-diamido-hexahydro-xylol, b.p. 27 io3-io5, m-diamido-hexa- 
 hydro-m-cymol, b.p. 10 I03-I05, from the corresponding hydroxyl- 
 amine oximes, gem-dimethyl-3, 5-diamido-cyelo-hexane, b.p. 10 103- 
 105 (A. 328, 105). Cp. also the ring amines of the terpane and 
 menthane groups, discussed among the terpenes. 
 
 EXTRA-CYCLIC HYDRO-AROMATIC AMINES. 
 
 Cyclo-hexyl-methyl-amine, hexahydro-benzyl-amine C C H 11 .CH 2 NH 2 , 
 b.p. 163, benzoyl compound, m.p. 108, from cyclo-hexyl-acetamide 
 with sodium hypo-bromite, and by reduction of hexahydro-benzo- 
 nitrile (A. 353, 298). With HNO 2 it is partly transformed into suberyl- 
 alcohol with ring expansion (A. 353, 326). 
 
 jS-Cyelo-hexyl-ethyl-amine C 6 H n .CH 2 .CH 2 NH 2 , b.p. 188, by reduc- 
 tion of cyclo-hexyl-aceto-nitrile (A. 353, 297). 
 
 (4) RlNG-KETONES OF THE HYDRO-AROMATIC HYDROCARBONS. 
 
 (a) Ring-ketones of Hexahydro-benzols. These belong to the most 
 easily accessible hydro-aromatic substances, starting from which 
 numerous other compounds can be prepared, and which have, there- 
 fore, been studied in detail. 
 
 Methods of Formation. (i) By oxidation of the corresponding 
 cyclo-hexanols with chromic acid, or by conducting their vapours 
 over finely divided metallic copper at 300 (C. 1903, 1. 1212). (2) From 
 cyclo-hexene-glycols with dilute acids. (3) By nuclear synthesis from 
 pimelinic acid and its alkyl substitution products by distillation of 
 their calcium salts or anhydrides (C. 1907, II. 685). (4) From the 
 synthetic cyclo-hexanone-carboxylic esters and their alkylation pro- 
 ducts by saponification and elimination of CO 2 . (5) By the action of 
 
KETONES OF HYDRO-AROMATIC HYDROCARBONS 457 
 
 NaNH 2 and halogen alkyl upon I, 3-methyl-cyclo-hexanone ; an H 
 atom in the neighbourhood of CO can be replaced by alkyl (C. 1905, 
 I. 605). (6) Several i, 2-alkyl-cyclo-hexanones have been obtained 
 from the Mg-compound of i, 2-chloro-cyclo-hexanone by transposition 
 with halogen alkylene (C. 1906, II. 126). 
 
 Behaviour. (i) Like the aliphatic ketones, cyclo-hexanones combine 
 with hydroxylamine, phenyl-hydrazin, semi-car bazide, prussic acid, 
 etc., some also with sodium bisulphite. (2) Reduction with N a and 
 moist ether produces cyclo-hexanols. (3) Sodium ethylate or gaseous 
 HC1 they, like acetone, undergo self-condensation with combination 
 of two or three molecules and elimination of water. (4) Cyclo-hexa- 
 nones condense with benzaldehyde, forming characteristic mono- or 
 di benzyl compounds by joining up two methylenes adjoining the CO 
 group (C. 1908, I. 638). (5) With acetic ester, and sodium, they form 
 i, 2-acetyl-cyclo-hexanones, with oxalic ester and sodium ethylate 
 i, 2-cyclo-hexanone-oxalic esters (A. 348, 91), with NaNH 2 and CO 2 
 i, 2-cyclo-hexanone-carboxylic acids (C. 1910, II. 1378). (6) With 
 PC1 5 unstable dichlorides are first formed, which decompose into HC1 
 and chloro-cyclo-hexenes. (7) KMnO 4 and NHO 3 oxidise them 
 clearly to adipinic acids with the grouping CO.CH 2 . (8) By 
 means of Caro's acid some have been split up into lactones (B. 33, 858). 
 (9) Cyclo-hexanone-oximes are converted into -lactames of concen- 
 trated H 2 SO 4 or PClg, and into the nitriles of unsaturated aliphatic 
 acids by P 2 O 5 with ring opening (A. 312, 173 ; 346, 266). (10) Sun- 
 light and water partly convert cyclo-hexanones into saturated fatty 
 acids, and the corresponding unsaturated aldehydes (B. 41, 1071). 
 
 
 B.p. 
 
 D. 
 
 
 
 Cyclo-hexanone 
 
 155-4 
 
 0-9471 
 
 (22) 
 
 
 2-Methyl-cyclo-hexanone . 
 
 163 
 
 0-9246 
 
 1 8) 
 
 ( 
 
 3-Methyl-eyclo-hexanone . 
 
 168 
 
 0-9111 
 
 18) 
 
 1 C. 1905, I. 742 
 
 4-Methyl-cyclo-hexanone . 
 
 169 
 
 0-9332 
 
 0) 
 
 1 
 
 2, 2-Dimethyl-cyclo-hexanone 
 
 170 
 
 0-9141 
 
 20) 
 
 A. 376, 159 
 
 3, 3-Dimethyl-cyclo-hexanone 
 
 174 
 
 . . 
 
 
 C. 1907, I. 964 
 
 3, 4-Dimethyl-cyclo-hexanone 
 
 187 
 
 . . 
 
 
 C. 1906, I. 1248 
 
 2, 6-Dimethyl-cyclo-hexanone 
 2, 4-Dimethyl-cyclo-hexanone 
 
 175 
 176-5 
 
 0-9124 
 
 (16) 
 
 B. 27, 594 
 
 C. 1906, I. 1248 
 
 3, 5-Dimethyl-cyclo-hexanone 
 
 182 
 
 0-8994 
 
 (17) 
 
 W. 297, 163 
 
 2, 5-Dimethyl-cyclo-hexanone 
 
 176 
 
 0-9083 
 
 13) 
 
 /C. 1906, I. 1248 
 \A. 357, 202 
 
 Cyclo-hexanone-pimelin-ketone, keto - hexameihylene 
 2 ~~ ** 2 \CO is an oil with an odour like peppermint. It 
 
 / 
 
 results (i) by the oxidation of cyclo-hexanol ; (2) in the reduction of 
 phenol with alternating currents ; (3) in the distillation of calcium 
 n-pimelinate or pimelinic anhydride (Vol. I.) ; (4) by the action of CO 2 
 upon i, 5-dibromo-pentane magnesium (C. 1907, II. 681) ; (5) from 
 nitro-hexamethylene by treatment with glacial acetic acid and zinc 
 dust (A. 302, 18). 
 
 Upon reduction it yields cyclo-hexanol, while nitric acid oxidises 
 it to adipinic acid (B. 39, 2202 ; C. 1905, I. 1243). By sodium ethylate 
 or HC1 two or three molecules of cyclo-hexanone are condensed, with 
 
458 ORGANIC CHEMISTRY 
 
 formation of cyclo-hexylidene-cyclo-hexanone (C 6 H 8 O) : (C 6 H 10 ), di- 
 cyclo-hexylidene-cyclo-hexanone (C 6 H 10 ) : (C 6 H 6 O) : (C 6 H 10 ), b.p. 214- 
 217, and dodeka-hydro-triphenylene (B. 40, 153). 
 
 Illumination of an aqueous-alcoholic solution of cyclo-hexanone pro- 
 duces capronic acid and A 5 -hexene-aldehyde. Cyclo-hexanone-oxime 
 is transposed by concentrated H 2 SO 4 in e-capro-lactame (see Vol. I.). 
 
 Its phenyl-hydrazone, melting at 74-77, when acted upon by 
 mineral acids loses ammonia and passes into tetrahydro-carbazol 
 (A. 278, 100). 
 
 With benzaldehyde, cyclo-hexanone condenses to a mono- and a 
 dibenzylidene compound C 6 H 5 CH : (C 6 H 8 O), m.p. 53 (B. 40, 71), and 
 C 6 H 5 CH : (C 6 H 6 O) : CHC 6 H 5 , m.p. 117. Under special conditions, it 
 was found possible to isolate the intermediately formed mono acid 
 di-aldols, m.p. 102 and 162 (C. 1908, I. 638). With nitrous acid we 
 obtain di-iso-nitro-cyclo-hexanone HON : (C H 6 O) : NOH, m.p. 200 
 with decomposition (C. 1909, II. 1549). Chlorine and bromine easily 
 produce substitution, with formation of I, 2-chloro- and i, 2-bromo- 
 cyclo-hexanone respectively, b.p. 10 82 and b.p. 14 89. With excess of 
 Br a tetrabromide is formed, m.p. 120, which, on heating, splits off 
 HBr and forms 2, 6-dibromo-phenol (A. 343, 40 ; /. pr. Ch. 2, 80, 487). 
 
 3 - Methyl - cyclo - hexanone CO/^ 2 CH(( ;!^ ) \CH 2 has been ob- 
 
 M_/rl 2 Url 2 / 
 
 tained in an optically active dextro-form of [a] D = 4-12-5 by splitting 
 up the natural pulegone (B. 30, 23; /. pr. Ch. 2, 61, 477). It is the 
 most accessible hydro-aromatic ketone. On oxidation with HNO 3 we 
 obtain simultaneously a- and j8-methyl-adipinic acid (A. 336, 299). 
 Its oxime, m.p. 44 (A. 332, 337), is transposed by concentrated H 2 SO 4 
 into a mixture of j8- and S-methyl-e-capro-lactame (A. 346, 253) . On its 
 conversion into m-cresol, see B. 32, 3338. From 3-methyl-cyclo- 
 hexanone the action of NaNH 2 and alkyl iodide produces 1-methyl- 
 4-ethyl- and l-methyl-4-propyl-cyclo-hexanone, b.p. 18 84 and 98 
 respectively, as well as numerous homologous cyclo-hexanones (see 
 synthesis of menthone, below). 
 
 2, 2-Dimethyl-cyclo-hexanone is formed from i-iso-propyl-cyclo- 
 pentane-i, 6-diol by pinacolin transformation and simultaneous ring 
 extension. 
 
 3, 5, 5-Trimethyl-cyclo-hexanone, dihydro-iso-aceto-phorone, b.p. 
 189, has been obtained from dihydro-iso-aceto-phorol, the reduction 
 product of iso-aceto-phorone, by oxidation with chromic acid mixture. 
 For transposition of the oximes, see A. 346, 256. 2, 4, 4-Trimethyl- 
 cyclo-hexanone, b.p. 191, from 2, 4, 4-trimethyl-cyclo-hexenone (A. 
 324, 97). 3, 6, 6-Trimethyl-cyclo-hexanone, see Pulenone. 
 
 Ring-ketols. 1,2-Cyelo-hexanolone co<^ (OH) - 2 \CH 2 , m.p. 
 
 \Uri2 (_/rl2/ 
 
 113, sublimes very easily, and is formed from i, 2-chloro-cyclo-hexa- 
 none with alkalies. It yields on oxidation with KMnO 4 adipinic acid 
 (C. 1906, II. 125 ; /. pr. Ch. 2, 80, 488). Methyl-1, 2-cyelo-hexanolone 
 CH 3 C 6 H,O(OH), b.p. 12 86, from methyl-bromo-cyclo-hexanone (B. 35, 
 2695). 3-Methyl-l, 2, 3-cyelo-hexanone-diol CH 3 C 6 H 7 O(OH) 2 , m.p. 65, 
 is formed from the synthetic methyl-cyclo-hexenone and from A 1 - 3 - 
 dihydro-toluol, by oxidation with KMnO 4 ; on boiling with dilute sul- 
 phuric acid it yields methyl-cyclo-hexane-dione (B. 35, 1176). i, 3- 
 
KETONES OF HYDRO-AROMATIC HYDROCARBONS 459 
 
 Cyclo-hexanolones must be assumed as intermediate products in the 
 formation of cyclo-hexenones from i, 5-diketones of the formula 
 
 < some of which ma ^ be C <^(O^>CH; < A ' 323 ' 8 3 ' B - 
 36, 2118). 
 
 Diketo-hexamethylenes, Cydo-hexane-diones. Theory indicates three 
 isomeric diketo-hexamethylenes, two of which, the I, 3- and the i, 4- 
 diketo-hexamethylene, are known, while of the o-diketo-hexamethylene, 
 up to now only a methyl derivative, l-methyl-2, 3-diketo-hexa- 
 methylene CH 3 .C 6 H 7 O 2 , m.p. 65, has been prepared ; it is formed from 
 methyl-cyclo-hexanone-diol by discarding water, and smells strongly 
 of quinone (B. 35, 1178). 
 
 Dihydro-resorcin, i, 3-cy do-he xane-dione, m-diketo-hexamethylene 
 CH/CH..CO \ co or CO/^^C^/ 011 * melts wit* 1 decomposition 
 
 \Crl 2 -^Al 2 / \UH 2 -Cxi^/ 
 
 at I04-io6. It is a feeble acid, and probably therefore an un- 
 saturated ketone alcohol of ring formation. It is produced upon 
 introducing pure sodium amalgam into a boiling aqueous resorcin 
 solution while carbon dioxide is being conducted into it. It may be 
 synthesised by the condensation of y-acetyl-butyric ester with sodium 
 ethylate. Dihydro-resorcin dissolves readily in water, alcohol, and 
 chloroform, but with difficulty in ether. It reacts acid, and decom- 
 poses the alkali and alkaline earth carbonates. It can be directly 
 esterified with alcohol and HC1. 
 
 It also forms a dioxime C 6 H 8 (NOH) 2 -f 2H 2 O. This melts at 154- 
 157 when it is anhydrous ; when reduced it becomes m-diamido- 
 hexamethylene. m-Dioxy-hexahydro-iso-phthalo-nitrile (A. 278, 20) 
 is formed by adding prussic acid to dihydro-resorcin (A. 308, 184). 
 PC1 3 produces chloro-keto-tetrahydro-benzol C 6 H 7 OC1, b.p. 24 104, 
 whereas PC1 5 produces diehloro-dihydro-benzol C 6 H 6 C1 2 , b.p. 29 89 
 (C. 1903, I. 1352) ; bromine gives 2-bromo-hydro-resorein C 6 H 7 O 2 Br. 
 NaOBr and bleaching-lime decompose hydro-resorcin into glutaric acid 
 and chloroform (A. 322, 245) ; by heating with baryta water to 150- 
 160 it is broken up into acetyl-butyric acid (A. 294, 269). 
 
 Homologues of dihydro-resorcin are similarly formed in the con- 
 densation of like S-ketone-carboxylic esters, as, for example, in the 
 addition of malonic esters to alkylidene-aceto-acetic ester. When 
 the latter is condensed with malonic ester, through the agency of sodium 
 ethylate, and the product then saponified, carbon dioxide is eliminated, 
 and there results methyl-dihydro-resorcin, m.p. 126 (A. 289, 137 ; 294, 
 253) : 
 
 CH 3 CH 3 CH S 
 
 C0 2 RCH.CH.CHC0 2 R y CO 2 RCH.CH. CHCO 2 R v CH 2 .CH.CH, 
 
 CO.CH 3 C0 2 R CO.CH 2 .CO CO.CH 2 .CO 
 
 Iso-propyl-dihydro-resorcin (CH 3 ) 2 CH.C 6 H 7 O 2 , m.p. 82 (C. 1902, II. 
 115). Phenyl-dihydro-resorcin (C 6 H 5 )C 6 H 7 O 2 , m.p. 184. 1, 2-Di- 
 phenyl-dihydro-resorcin, m.p. 160, from phenyl-acetic ester, benzal- 
 acetone, and sodium ethylate (B. 42, 4498). 
 
 Cinnamenyl-dihydro-resorem (C 6 H 5 CH : CH)C 6 H 7 O 2 , from cinna- 
 mylidene-acetone and Na-malonic ester, is changed, by bleaching-lime, 
 into cinnamenyl-glutaric acid (A. 345, 206). 
 
460 ORGANIC CHEMISTRY 
 
 Dimethyl-hydro-resorcin (CH 3 ) 2 C : [CH 2 CO] : CH 2 , m.p. 150, from 
 mesityl oxide, and sodium-malonic ester, gives, with NaOBr and 
 bleaching-lime, jSjjS-dimethyl-glutaric acid (A. 368, 135). For halogen 
 derivatives of dimethyl-hydro-resorcin, see A. 322, 239. For the trans- 
 formation of dimethyl-dihydro-resorcin into dimethyl-di- and tetra- 
 hydro-benzol, see C. 1908, I. 1779. Trimethyl-dihydro-resorcin, m.p. 
 100 (C. 1-900, I. 1069 ; 1901, I. 567). 
 
 The homologous dihydro-resorcins react like simple dihydro-resorcin, 
 both as diketones and as unsaturated oxy-ketones. 
 
 1, 4-Cyclo-hexane-dione, tetrahydroquinone, p-diketo-hexamethylene 
 
 </""*TT f^T-T \ 
 
 ^TT 2 ^TT 2 / co > m -P- 78, results upon saponifying succino-succinic 
 .C/xig (--.rig/ 
 
 ester with concentrated sulphuric acid, when it loses carbon dioxide 
 (Baeyer), or when the same body is boiled with aqueous alcoholic 
 hydrochloric acid. On heating succinyl-succinic ester with methyl 
 or ethyl alcohol to 200, acetals of p-diketo-hexamethylene are formed, 
 methyl acetal, m.p. 81, ethyl acetal, m.p. 89 (B. 34, 1344). In small 
 quantities, p-diketo-hexamethylene is also produced by distillation of 
 calcium succinate. 
 
 It unites with sodium bisulphite to form a dioxime, melting at 192 ; 
 the latter is changed by chlorine into p-dichloro-dinitroso-hexa- 
 methylene (ON)CC1(CH 2 .CH 2 ) 2 CC1(NO), deep-blue crystals, m.p. 108, 
 changed by glacial acetic-hydrochloric acid into a colourless form 
 melting at I28-I3O with decomposition (B. 35, 3101). With benz- 
 aldehyde and HC1 p-diketo-hexamethylene forms benzyl-hydroquinone 
 (B. 37, 3486). It forms quinite upon reduction ; see also a-Dioxy-hexa- 
 hydro-terephthalic acid. 
 
 p-Dimethyl-p-diketo-hexamethylene, 2, 5-dimethyl-i, ^-cyclo-hexane- 
 dione, m.p. 93, is obtained from p-dimethyl-succino-succinic ester 
 
 (B. 25,2122). 
 
 Cyclo-hexane-triones. Phloro-glucin yields derivatives which can be 
 deduced from the formula of I, 3, 5-trioxy-benzol, and others which 
 can be obtained from the formula of i, 3, 5-triketo-hexamethylene. 
 It was discussed at the conclusion of pyrogallol and oxy-hydroquinone, 
 as were the hexa-alkyl derivatives of phloro-glucin. 
 
 Triquinoyl C 6 O 6 -[-8H 2 O, described with the quinones, is probably 
 hexaketo-hexamethylene. 
 
 Halogen Substitution Products of the Ring-ketones of Hexahydro- 
 benzol are formed in the continuous action of chlorine and bromine 
 upon phenols, quinones, and oxy-quinones. Several of the keto- 
 chlorides can be readily rearranged into halogen keto-pentene deriva- 
 tives, and be decomposed into highly chlorinated fatty bodies : ketones, 
 ketonic acids, and fatty acids. 
 
 Heptachloro-resorcin, heptachloro - 1, 3-cyclo-hexane-dione 
 
 C0 ^CH 2 ^a) >CH2 ' m ' p ' 5 ' b>p>25 I7 ' from resorcin and C1 in 
 chloroform (B. 24, 912). 
 
 Quinone tetrabromide, 2,3,5,6- tetrabromo - cyclo - hexane - dione 
 
 Hexachloro-triketo-R-hexylene, hexachloro- 
 
 , 3, S-cyclo-hexane-trione CO/^J 2 ~ Ncci 2 , m .p. 48, b.p. 268, from 
 
 
 
 phloro-glucin with Cl in chloroform (B. 22, 1473). 
 
KETONES OF HYDRO-AROMATIC HYDROCARBONS 461 
 
 Pentabromo-diketo-oxy-cyclo-hexenol co^co / CBr +H!!O ' 
 m.p. 119 with decomposition. It is produced when bromine in water 
 acts upon phloro-glucin. It forms amber-yellow-coloured crystals. It 
 is a strong acid. 
 
 Hexabromo-triketo-cyclo-hexane C 6 Br 6 O 3 melts at 147 (B. 23, 
 
 I 7 2 9) 
 
 Tri- and tetrachloro - tetraketo - cyclo - hexanes co 
 
 They are obtained from chloranilic acid and chlorine. The correspond- 
 ing bromine derivatives are made from bromanilic acid (B. 25, 845). 
 
 (b) Ring-ketones from the Tetrahydro-benzenes can be synthesised 
 by condensing aceto-acetic ester, acetone-dicarboxylic ester, and ana- 
 logous compounds with aldehyde iodides, like methylene iodide, or with 
 aldehydes in the presence of small quantities of bases, such as diethyl- 
 amine or piperidin, to i, 5-diketone-carboxylic esters e.g. methylene-, 
 ethylidene-, iso-butylidene-diaceto-acetic ester and methylene bis- 
 acetone-dicarboxylic ester. When the latter are treated with hydro- 
 chloric acid in ether, they first form a ring and become carboxylic esters 
 of A 2 -keto-R-hexenes, and then, when acted upon with alkalies or 
 dilute acids, are saponified, split off C0 2 , and change to the ketones 
 themselves (A. 289, 131) : 
 
 C0 2 .C 2 H 5 .CH.CO.CH 3 C0 2 .C 2 H 5 .CH.C.CH 3 CH 2 .C.CH 3 
 
 CH 2 - '-+ CH 2 CH - > CH 2 CH 
 
 CO 2 .C 2 H 5 .CH.CO.CH 3 CO 2 .C 2 H 5 .CH.CO CH 2 .CO 
 
 From acetyl-acetone with aldehydes we obtain 8 2 -tetraketone 
 (CH 3 COCH) 2 CHR(CHCOCH 3 ) 2 , which, on twofold ring condensation, 
 yields dicyclic systems whose structure has still to be determined 
 (B. 30, 2136). 
 
 From the nitroso-chlorides of some cyclo-hexenes A 2 -cyclo-hexe- 
 nones have been prepared by splitting oft HC1 by means of sodium 
 ethylate or sodium acetate and glacial acetic acid, and breaking up the 
 resulting oxides with oxalic acid or phthalic anhydrides. 
 
 By reduction with sodium and alcohol we obtain from A 2 -cyclo- 
 hexenones the saturated cyclo-hexanols. But if we reduce with sodium 
 amalgam in acid solution, two molecules are combined and we obtain 
 derivatives of diketo-perhydro-diphenyl. 3-Methyl-A 2 -cyclo-hexenone 
 CH 2 <(^ 2 -CHa\ C(CH3) . q ^^ By the action of two 
 
 molecules of hydroxylamine, oximes are formed. Thus, from 3- 
 methyl-A 2 -cyclo-hexenone we get 3-methyl-3-hydroxylamino-cyclo- 
 hexanone-oxime (B. 32, 1315). 
 
 A 2 -Cyelo-hexenone co/ c 3HN )CH 2 , b.p. 14 63, bromo-cyclo- 
 
 \CH 2 CH 2 / 
 
 hexanone, on boiling with aniline, or from I, 2-cyclo-hexanolone with 
 anhydrous oxalic acid. Its unstable dibromide easily passes into phenol 
 by splitting off HBr. The oxime melts at 75 and yields aniline on 
 boiling with acetic anhydride. Oxamine oxime, m.p. 50 (/. pr. Ch. 
 2, 80, 487). 
 
 3-Methyl-A 2 -eyclo-hexenone co^ =c(C r I 5 ) \CH 2 , b.p. 200, forms 
 
462 ORGANIC CHEMISTRY 
 
 a mobile liquid of pleasant odour. Its bromine addition-product de- 
 composes spontaneously into BrH and m-cresol. It seems to exist in 
 two isomeric forms, one of which can be mixed with water, while the 
 other is difficult to dissolve. They are of identical chemical behaviour, 
 and both are oxidised by permanganate to y-acetyl-butyric acid (B. 
 40, 2482). The oxime, m.p. 89, gives, on boiling with acetic anhydride, 
 m-toluidin (A. 322, 382). The hydroxylamino-oxime, m.p. 84, gives, 
 by oxidation with mercuric oxide, a nitroso-oxime. By heating with 
 concentrated potash, the 3-methyl-A 2 -cyclo-hexenone is changed into 
 a polymerisation product resembling an aldol, melting at 113 (B. 32, 
 423 ; A. 297, 142). With sodium-aceto-acetic ester it combines to 
 form 5-diketone-carboxylic ester, which by ring-condensation passes 
 into a bicyclic ketone-alcohol (B. 37, 1671). 
 
 2-Methyl-A 2 -cyclo-hexenone co?^ H3) = ^ >CH 2 , b.p. 179, from 
 
 \(_,H 2 U.H.2/ 
 
 the nitroso-chloride of A^methyl-cyclo-hexene (A. 359, 303). 
 
 4-Iso-propyl-A 2 -cyclo-hexenone co/^ =c?\:H.CsH 7f b.p. la 94, 
 
 \Cri 2 C.H.2/ 
 
 semi-carbazone, m.p. 185, is formed by heating sabina-ketone and 
 nopinone with dilute sulphuric acid and by the self-oxidation of j3- 
 phellandrene. It polymerises very easily, especially in the presence of 
 alkali. With methyl-magnesium iodide water is split off and a-phel- 
 landrene is formed (A. 359, 270). 
 
 4-Iso-propyl-A 3 -eyclo-hexenone co<f^ 3 ~~ c T f V.QH,, b.p. 12 95, 
 
 \CH 2 C H 2 / 
 
 semi-carbazone, m.p. 170, is formed from the HC1 addition product of 
 sabina-ketone by heating with dimethyl-aniline. Mineral acids trans- 
 pose it into the A 2 -ketone. With methyl-magnesium iodide it yields 
 terpinenol-i (A. 362, 280). 
 
 1, 4-Iso-propylidene-eylo-hexanone co^ CH * cu *\c : c/ 01 ^ b.p. 
 
 NCH 2 CH 2 / \CH 3 
 
 220, semi-carbazone, m.p. 200, from the corresponding carboxylic 
 ester (C. 1907, II. 1975). 1, 4 - Iso - propenyl - cyclo - hexanone 
 
 C <CHlIcH2> CH ' C \CH^ b - P ' 300 I85 (C I9 4 ' IL 33I) ' 
 
 3, 5-Dimethyl-A 2 -eyelo-hexenone, b.p. 211. Its dibromide easily 
 passes into sym. xylenol (A. 281, 121) ; its oxime, m.p. 68-74, is 
 transposed, by heating with HC1, into sym. xylidene (A. 322, 381). 
 
 5, 5-Dimethyl-A 2 -cyclo-hexenone, b.p. 32 85-5, from dimethyl- 
 chloro-cyclo-hexanone, the product of the action of PC1 3 upon dimethyl- 
 dihydro-resorcin, by reduction with zinc dust. With permanganate 
 it gives a-oxy-jSjjS-dimethyl-glutaric acid and unsym. dimethyl- 
 succinic acid (C. 1907, I. 1039). 
 
 3, 5, 5-Trimethyl-A 2 -cyclo-hexenone, iso-aceto-phorone, iso-phorone 
 C 9 H 14 0=CO<^ =C \ ^>CH 2 , boiling at 89 (10 mm.), is produced 
 
 \Ura 2 M^^S/2' 
 
 in the condensation of mesityl oxide with aceto-acetic ester, saponifica- 
 tion, and elimination of carbon dioxide from the carboxylic ester 
 formed at first. It also results from the condensation of acetone 
 by means of lime or sodium ethylate. It is isomeric with phorone, 
 camphor-phorone, iso - camphorone, nopinone, camphenilone, and 
 fencho-camphorone. Upon reduction with sodium and alcohol it 
 forms dihydro-iso-phorol C 9 H 17 (OH), which by loss of water becomes 
 
KETONES OF HYDRO-AROMATIC HYDROCARBONS 463 
 
 trimethyl-cyclo-hexene, and by the reduction of its iodide yields 
 trimethyl-cyclo-hexane. When oxidised with potassium permangan- 
 ate the ring is ruptured and various acids result : yy-dimethyl- 
 a, 2-diketo-heptylic acid C S H 14 O 4 , y-acetyl-j3j3-dimethyl-butyric acid 
 C S H 14 O 3 , and unsym. dimethyl-succinic acid (C. 1909, I. 853). 
 
 The iso-phorone gives two isomeric oximes melting at 75 and 100 
 respectively (A. 297, 187 ; 299, 165, 193), which are transposed, by 
 heating with HC1 to 170, into i-amido-3, 4, 5-trimethyl-benzol (A. 
 322, 379). Besides iso-phorone, we find among the condensation pro- 
 ducts of acetone more highly condensed ketones, the so-called xyli- 
 tones C 12 H 18 O, probably formed by condensation of a further molecule 
 of acetone with iso-phorone ; the xylitones produced by different con- 
 densation agents, such as lime, sodium ethylate, and HC1, seem all to 
 differ from one another. An identically situated xylitone, which, how- 
 ever, is not identical with any of the others, and melts at 133 (12 mm.), 
 has been obtained by the addition of sodium-aceto-acetic ester and 
 phorone. By boiling with formic acid it is split up into acetone and 
 iso-phorone (B. 39, 3441). 
 
 2, 4, 4-Trimethyl-A 2 -eyclo-hexenone, b.p. 196, by transformation 
 of a-cyclo-geraniolene nitroso-chloride (A. 324, 97). 
 
 3-Methyl-5-iso-propyl-A 2 -cyclo-hexenone 
 
 boils at 244. Its dibromide passes readily into sym. carvacrol (B. 26, 
 1089 ; 27, 2347 ; A. 288, 357). 
 
 3-Methyl-5-iso-butyl- and 3-methyl-5-hexyl-A 2 -eyclo-hexenones 
 
 boil at 147 and at 167 (22 mm.) (B. 288, 336, 344). 
 
 Those chemists who consider the quinones to be ketones regard 
 rhodizonic acid as a tetraketo-tetrahydro-benzol derivative. 
 
 4-Methyl- and 2, 4-dimethyl-A 2 -eyclo-hexenones, b.p. 192 and 194, 
 are found among the ketones of wood-tar (C. 1901, I. 611). 
 
 Halogen Substitution Products of Ring-ketones of Tetrahydro-benzols 
 result when chlorine acts upon phenols, anilines, oxy-benzoic acids, etc. 
 They can be very readily broken up. 
 
 Heptachloro - keto - tetrahydro - benzols cci/^f. \x> and 
 
 \OHC1 CCi2/ 
 
 CC1 \CHci^CCl 2 ^ C0 ' the a ' bod y meltin g a t 98 and the ^-modification 
 at 80, result from the action of chlorine upon m-chloraniline 
 (B. 27, 547)- 
 
 Octo - chloro - keto - tetrahydro - benzol cci,/ c ' Nco, or 
 
 \V-/ v/1 2 - V^x-'l 2 * 
 
 CC1 \CC1~^CC1^X' melting at 103, result from the action of chlorine 
 
 upon pentachloro-phenol in glacial acetic acid, and from perchloro-m- 
 oxy-benzoic acid. Reducing agents change it into pentachloro-phenol 
 (B. 27,550). 
 
 Hexachloro - o - diketo-tetrahydro-benzol cci^ 001 *^ 00 ^>co + 2 H a o 
 
 melts at 93 with decomposition. It is formed when chlorine acts 
 upon pyro-catechol and o-amido-phenol chlorohydrate dissolved in 
 acetic acid. Stannous chloride reduces it to cyclo-benzo-quinone. 
 Homologous o-diketo-chlorides have been obtained from o-diamido- 
 methyl-benzols (B. 27, 560). 
 
464 ORGANIC CHEMISTRY 
 
 Pentaehloro - m - diketo-tetrahydro-benzol c ocQ^H/^ ccl2 ' m ' p ' 
 92 and b.p. 160 (25 mm.), results when chlorine acts upon resorcin 
 in chloroform (B. 23, 3777). 
 
 Hexachloro - m - diketo-tetrahydro-benzol co<^~ ;^ 2 \:ci 2 , m.p. 
 
 \OG1 GC1 / 
 
 115 and b.p. 159 (14 mm.), is produced when chlorine acts upon 
 3, 5-dioxy-benzoic acid dissolved in glacial acetic acid (B. 25, 2688). 
 
 Hexachloro - p - diketo-tetrahydro-benzol co<^ ccl ^7 ccl2 ^>co, m.p. 
 
 89 and b.p. 184 (45 mm.), is formed when chlorine acts upon p-amido- 
 phenol hydrochloride in glacial acetic acid (A. 267, 16). 
 
 (c) Ring-ketones of the Di hydro-benzols. There are two possible 
 dihydro-benzols, and from each one monoketone can be obtained. Both 
 bodies are not yet known, but in tetrachloro-keto-dihydro-benzol 
 
 m< - I06 ' WC have chlorine 
 
 derivatives of one or of both keto-dihydro-benzols. The first body 
 is formed from trichloro-phenol and chlorine, and the second, most 
 conveniently, by heating (B. 27, 546) the heptachloro-keto-tetra- 
 hydro-benzol, melting at 98, and by treating phenol, anisol, and penta- 
 chloraniline with chlorine (B. 28, R. 63). 
 
 Among the ring-ketones of the dihydro-benzols we must also include 
 a series of substances obtained as by-products in the action of chloro- 
 form and alkali, or of carbon tetrachloride and aluminium chloride 
 upon o- and p-alkylated phenols, e.g. : 
 
 /CH=CH\ /R /CH=CH\ /R /CH-COX /R 
 
 \CH=CH/ \CHC1 2 ' \CH=CH/ \CC1 3 ' \CH=CH/ \CHC1 2 
 
 Thus, compounds which are reconverted into the original phenols 
 by reduction with zinc dust and glacial acetic acid, and reduction of 
 CH 2 C1 2 or CHC1 3 , react with phenyl-hydrazin, hydroxylamine, and semi- 
 carbozide like ketones (B. 36, 1861). Special interest attaches to the 
 further transformations of these ketones with alkyl-magnesium com- 
 pounds. The ketones (i) derived from the p-alkyl-phenols yield 
 normal tertiary alcohols (2) which easily split off water and become 
 unstable alkylidene-dihydro-benzols (3), and change into true benzol 
 derivatives (4) on heating at ordinary temperatures with migration of 
 the CHC1 2 group or the CC1 3 group (A. 352, 219). 
 
 (i) 
 
 CH 3 \ /CH=CH\ CH,Mgl CH 3 \ /CH=CH\ /OH 
 
 C1 2 CH/ \CH=CH/ / C1 2 CH/ \CH=CH/ \CH 3 
 
 (3) 
 
 CH 3 \ /CH=CH\ 
 C1 2 CH/ C \CH=CH/ 
 
 Different behaviour is shown by the ketones derived from the 
 o-alkyl-phenols. These (5) attach the alkyl-magnesium compounds to 
 the carbon double link and form higher homologous j8, y-unsaturated 
 ketones (6), which, by the action of concentrated sulphuric acid, dis- 
 place the double link and pass into the isomeric a, j3-unsaturated 
 ketones (7). The latter, on heating with alcoholic potash, yield 
 
KETONES OF HYDRO-AROMATIC HYDROCARBONS 465 
 
 I, 4-dialkyl-cyclo-hexadienes (8), by a curious reaction with inter- 
 mediate formation of p-dialkyl-dihydro-benzoic acids (B. 42, 2404) : 
 
 (5) (6) 
 
 CH 3 \^ /CO CH\ CH.Mgi CH 3\ r /CO CH. 
 C1 2 CH/^\CH-CH/ / C1 2 CH/ \CH=CH 
 
 (7) / (8) 
 
 CH 3 \ /CO CH\ 
 C1 2 CH/ C< \CH-CH 2 / CCH3 
 
 By using iso-propyl-magnesium iodide we get a synthesis of a- 
 terpinene (Auwers). 
 
 l-Methyl-4-dicnloro-methyl-keto-dihydro-benzol, m.p. 55, changes, 
 under the action of PC1 5 , with intermediate formation of an unstable 
 tetrachloride and migration of the methyl group, into trichloro-o-xylol 
 Cl[5]C 6 H 3 [i]CH 3 [2]CHCl 2 . With CH 3 MgI it forms 1, 4-dimethyl-4- 
 dichloro-methyl-oxy-dihydro-benzol (2), m.p. 96, which easily decom- 
 poses into water and l-methylene-4-methyl-4-dichloro-methyl-dihydro- 
 benzol (3), a yellowish oil. On heating, the latter transposes into 
 l-methyl-4-(j8)-dichlorethyl-benzol (4), which, with concentrated 
 H 2 SO 4 , passes into m-xylol-aldehyde, with migration of the methyl 
 group. 
 
 4-M ethyl - 4- trichloro- methyl -keto-dihydro-benzol 
 
 ca'X^cH-cH^ 00 ' m ' p ' I05 ' oxime ' m ' p - I34 ' from P- cresol > CQ 2> 
 and A1C1 3 , behaves like the corresponding dichloro-compound (B. 41, 
 897). 
 
 2-Methyl-2-dichloro-methyl-keto-dihydro-benzol (5), m.p. 33, b.p. 9 
 113, gives, with CH 3 MgI, 3, 6-dimethyl-6-dichloro-methyl-A 4 -cyclo- 
 hexenone, dichloro-f$, y-pulenone (6), b.p. 124 (15 mm.), which is con- 
 verted by H 2 SO 4 into the isomeric 3, 6-dimethyl-6-dichloro-methyl-A 2 
 cyclo-hexenone, dichloro-afi-pulenone (7), m.p. 41, b.p. 15 151 ; the 
 latter, with alcoholic potash, gives A 1 ' 3 -dihydro-p-xylol (8), and by 
 reduction with Na and alcohol 3, 6, 6-trimethyl-cyelo-hexanol or 
 pulenol. 
 
 The methylene-quinones and qitinols, discussed in connection with 
 phenol alcohols, are probably also monoketones, derivable from 
 A^-dihydro-benzol : 
 
 /CH=CH\ /CH=CH\ /R 
 
 \CH=CH/ \CH=CH/ \OH' 
 
 Each of the possible dihydro-benzols also yields a diketone : 
 CH \CH-CH 2 ) >CH2 AU - Dih y dr - benzo1 CH 2<(.cH-CH/ >CH2 AM - Dihydr - benzo1 
 
 o-Benzo-quinone, rO< /= TO p-Benzo-quinone. 
 H CH/ o-diketo-dihydro-benzol \CH CH/ p-diketo-dihydro-benzol 
 
 If the diketone formula is preferred for the benzo-quinones, pre- 
 viously discussed with the phenols, then p-benzo-quinone is p-diketo- 
 dihydro-benzol, and its numerous derivatives are also deducible from 
 the latter compound. o-Benzo-quinone would be o-diketo-dihydro- 
 benzol. 
 
 VOL. II. 2 H 
 
466 ORGANIC CHEMISTRY 
 
 (5) HYDRO-AROMATIC ALDEHYDES. 
 
 Concerning the production of hydro-aromatic aldehydes, which is 
 connected in general with well-known reactions, we must remark 
 that their production from the calcium salts of the hydro-aromatic 
 carboxylic acids, by distillation with calcium formate, is not a straight- 
 forward reaction, and is often accompanied by transpositions. On 
 the other hand, the conversion of the hydro-aromatic carboxylic acids 
 into the corresponding aldehydes, by the transformation of the acid 
 anilides into the anilide chlorides (i), and diphenyl-amidines (2), the 
 reduction of the latter with sodium and alcohol (3), and the splitting 
 up of the resulting alkylidene-dianilines with dilute sulphuric acid (4), 
 can be successfully carried out (B. 41, 2064). 
 
 RCONHC 6 H 6 - -> RCC1 2 NHC 6 H 5 Q- 
 
 (3)/ 
 
 NHC 6 H 5 (4) 
 
 Hexahydro-benzaldehyde C 6 H n .CHO, b.p. 162, is formed (i) by 
 oxidising cyclo-hexyl-carbinol with chromic acid ; (2) from the 
 glycol of methene-cyclo-hexane with dilute H 2 SO 4 (A. 347, 331) ; (3) 
 from the synthetic cyclo-hexyl-glycidic ester by saponification and 
 CO 2 rejection (C. 1906, I. 1423). It smells of oil of bitter almonds 
 and valeraldehyde, and polymerises readily to meta-hexahydro-benz- 
 aldehyde (C 7 H 12 O) 2 , m.p. 202 (B. 40, 3050). Oxime, m.p. 91 ; semi- 
 carbazone, m.p. 174. By methods 2 and 3 numerous homologous 
 aldehydes have been obtained : o-, m-, and p-hexahydro-tolyl-alde- 
 hydes CH 3 .C 6 H 10 CHO, b.p. 15 61, 60, and 63. 2, 6, 6-Trimethyl-hexa- 
 hydro-benzaldehyde, b.p. 10 59, by reduction of j8-cyclo-citral with H 
 and colloidal palladium (B. 42, 1635). 
 
 A 1 -Tetrahydro-benzaldehyde C 6 H 9 .CHO, an oil smelling strongly of 
 benzaldehyde, formed by HC1 rejection from the nitroso-chloride of 
 methene-cyclo-hexane, by means of sodium acetate and glacial acetic 
 acid. Oxime, m.p. 58. Semi-carbazone, m.p. 212. In a similar 
 manner the tetrahydro-tolyl-aldehydes are formed (A. 359, 292). 
 A 3 -Tetrahydro-benzaldehyde, b.p. 17 58, from A 3 -bromo-cyclo-hexene- 
 magnesium and orthoformic ester (B. 43, 1040). 
 
 2, 6, 6-Trimethyl - tetrahydro - 2 - benzaldehydes, cyclo - citrals. Of 
 these aldehydes, important for the synthesis of violet perfumes, all 
 four linkage isomers are known : 
 
 CH 3 CH 3 
 
 V V Y Y 
 
 H 2 C CCHO H 2 C CH.CHO H 2 C CH.CHO ttC CH.CHO 
 
 H a C CCH 3 H 2 C CCH 3 HC CH.CH 3 HC CH.CH 3 
 
 CH a CH CH CH 2 
 
 A 1 - or A 2 - or A 3 -cyclo-citral A 4 -cyclo-citral. 
 
 /3-cyclo-citral a-cyclo-citral 
 
HYDRO-AROMATIC ALDEHYDES 467 
 
 a-Cyclo-citral, b.p. 20 90-95, D 0-925, semi-carbazone, m.p. 204, 
 and -eyclo-citral, b.p. 10 88-9i, D 20 0-957, semi-carbazone, m.p. 
 167, are obtained together from the a-cyclic terpene-alcohol citral by 
 changing the latter into aniline, and then condensing to a ring by means 
 of sulphuric and phosphoric acids (C. 1901, II. 716). See also B. 33, 
 3720. They are also produced by the oxidation of cyclo-geraniol. 
 a- and -Cyclo-citral oxidise in air to the corresponding cyclo-geranic 
 acids. With acetone and sodium alcoholate a-cyclo-citral condenses 
 to a-ionone, and /2-cyclo-citral to j8-ionone. 
 
 For the synthesis of A 3 - and A 4 -cyclo-citrals we start from iso- 
 phorone-carboxylic ester (i), which, by reduction with Na, yields a 
 mixture of cis-trans-isomeric oxy-acids (2), which, on discarding water, 
 pass into A 3 -cyclo-geranium acids (3) . PC1 5 changes the iso-phorone- 
 carboxylic ester into S-chloro-cyclo-geraniol-adiene-car boxy lie acid (4), 
 from which, by reduction, together with the A 2 - and A 3 -acids, A 4 -cyclo- 
 geranium acid (5) is obtained : 
 
 CH, CH, CH, CH. CH, CH, CH, CH, CH, CH, 
 
 V V V V V 
 
 (5) C (4) C (i) C (2) C (3) C 
 
 /\ 
 HC CH.CO,H< HC CH.CO 2 H H,C CH.CO,R > H,C CH.CO,H >-H,C CH.CO a H 
 
 HC CH.CH 3 C1C CCH, OC C.CH, HOHC CH.CH, HC CH.CH, 
 
 \y \s \/- \s \/ 
 
 CH, CH CH CH, CH 
 
 The A 3 - and A 4 -cyclo-geranium acids so obtained are changed by 
 the method given above into A 3 -cyelo-eitral, b.p. 12 76, and A 4 -cyclo- 
 citral. With acetone the A 3 -cyclo-citral condenses to a-irone, and 
 the A 4 -cyclo-citral to j3-irone, which is identical with the irone ex- 
 tracted from violet roots (Merling and Welde, A. 366, 119). Isomeric 
 trimethyl-tetrahydro-benzaldehydes, see C. 1903, II. 78. 
 
 Dihydro-benzaldehyde C 6 H 7 .CHO, b.p. 120 122, is formed from 
 anhydro-ecgonin dibromide (q.v.) with sodium carbonate. By gentle 
 oxidation with Ag 2 O it gives A^-dihydro-benzoic acid (B. 26, 454 ; 
 
 31, 1545). 
 
 Dihydro-cumin-aldehyde C 3 H 7 .C 6 H 6 .CHO, semi-carbazone, m.p. 
 202 ; oxime, m.p. 43 ; by reduction of nitro-fi-phellandrene (A. 
 340,3). 
 
 (6) EXTRA-CYCLIC HYDRO-AROMATIC KETONES. 
 
 Among these compounds we have the important violet perfumes, 
 irone and the ionones. 
 
 Preparation. (i) Oxidation of extra-cyclic secondary alcohols ; (2) 
 from a-alkyl-cyclo-hexyl-glycidic esters by saponification and rejection 
 of CO 2 ; (3) by condensation of cyclo-hexanone with acetic ester and 
 sodium ; (4) ring-unsaturated ketones are obtained from the nitroso- 
 chlorides of alkylidene-cyclo-hexanes by deprivation of HC1 and split- 
 ting up the resulting oximes (A. 360, 39). 
 
 Hexahydro-aceto-phenone C 6 H n .COCH 3 , b.p. 12 68, by methods 
 i and 2, and from the synthetic a-acetyl-cyclo-hexane-car boxy lie ester. 
 2-, 3- and 4-Methyl-hexahydro-aceto-phenone CH 3 .C 6 H 10 .COCH 3 , b.p. ]8 
 78, b.p. 38 99, and b.p. 14 75, by method 2 (C. 1907, II. 332). 
 
 1, 1-Methyl-acetyl-eyelo-hexane CH 2 c H3 , b.p. 18 
 
468 ORGANIC CHEMISTRY 
 
 83, from iso-propyl-cyclo-hexane-i, 7-diol with dilute SO 4 H 2 (C. 1910, 
 II. 466). 
 
 Hexahydro-propio-phenone C 6 H n .CO.CH 2 .CH 3 , b.p. 196, by oxida- 
 tion of cyclo-hexyl-ethyl-carbinol, or by action of zinc ethyl upon 
 hexahydro-benzoyl-chloride (B. 42, 2230). 
 
 Cyclo-hexyl-aeetone C 6 H 11 .CH 2 .CO.CH 3 , b.p. 196, from cyclo- 
 hexyl-aceto-acetic ester (B. 42, 2236). 
 
 2-Acetyl-cyclo-hexanone C 6 H 9 O.COCH 3 , b.p. 18 m, by method 3. 
 Alkalies break it up into acetyl-capronic acid. It can be alkylated 
 by means of sodium and alkyl iodide (C. 1906, I. 252). 
 
 3, 6-Methyl-acetyl-cyclo-hexanone C 6 H 8 O[3, 6](CH 3 )(COCH 3 ), b.p. J4 
 
 122 (C. 1901, I. 683). 2-Propionyl-eyclo-hexanone C 6 H 9 O.COC 2 H 5 , 
 
 'b.p. 21 123, is formed by nuclear synthesis from z-ketononylic ester 
 
 and Na ethylate (C. 1909, II. 119). 
 
 A^Tetrahydro-aeeto-phenone CH.*~c.COCa J b.p. 201, 
 
 M_,ri 2 Cri 2 
 
 from the nitroso-chloride of ethylidene-cyclo-hexane, and by the action 
 of acetyl chloride and A1C1 3 upon cyclo-hexene. Oxime, m.p. 99 
 (C. 1910, I. 1785). 
 
 4-Methyl-A 1 -tetrahydro-aceto-phenone, b.p. 213. An isomeric 
 4-methyl-A 3 -tetrahydro-aceto-phenone, b.p. 206, has been obtained 
 by the oxidation of j8-terpineol (A. 324, 89). 
 
 Irone (formula below), b.p. 144, D 20 0-939, [a] D =+44, was 
 obtained by Tiemann and Kriiger (B. 26, 2675) from the etheric 
 oil of so-called violet root of Iris florentina, Iris germanica, and 
 Iris pallida. When diluted, it possesses an intense smell of violets. 
 On boiling with HI and P, irone splits off water and forms irene, 
 a hydrated naphthalene hydrocarbon, which can be broken up by 
 a series of oxidations into dehydro-irene, iregenone-di- and tri- 
 carboxylic acid, ion-iregene-tricarboxylic acid, and dimethyl-homo- 
 phthalic acid : 
 
 CH 3 CH 3 
 
 C CH 
 
 /\/\ 
 HC CH CH > HCO 2 C CH 
 
 II II II I 
 
 HC CH CO.CH 3 HC CH C.CH 3 HCO 2 C CCO 2 H 
 
 CH 2 CH 3 CH 2 CH CO CH HCO 2 CH 
 
 Irone Irene Iregenone- Dimethyl- 
 
 tricarboxylic acid homo-phthalic 
 acid. 
 
 a-Ionone, b.p. 12 127, D 20 0-9301, and /Monone, b.p. 10 127, D 20 
 0-9442 (Tiemann, B. 26, 2691 ; 31, 808), possess an intense odour 
 of violets closely approaching that of irone, and they are therefore 
 made on a large scale. Their occurrence in the vegetable kingdom 
 has not yet been established with certainty. They are formed by 
 condensation of a- and j3-cyclo-citral with acetone and sodium ethylate, 
 or by inversion of pseudo-ionone by means of concentrated sulphuric 
 acid, phosphoric acid, or by heating with aqueous salt solutions to 
 190 under pressure (C. 1905, I. 783). 
 
 In the latter case we obtain a mixture of various quantities of 
 
HYDRO-AROMATIC CARBOXYLIC ACIDS 469 
 
 a- and jS-ionone, the formation of which can be explained by the 
 successive attachment and rejection of water : 
 
 CH, CH, 
 
 H,C N C.CH : CH.COCH, 
 CH, CH 3 CH, CH, 
 
 
 HC CH.CH : CH.COCH, H S C CH,.CH : CHCOCH, 
 
 H,C C.CH, 
 
 CH, 
 
 /3-Ionone 
 
 CH, CH, 
 
 V 
 
 I,C CH.( 
 
 H,C CH.CH : CHCOCH, 
 
 -> I ! 
 
 H.C C.CH, 
 
 H C C.CH, H,C C(OH).CH, 
 
 CH, CH, 
 
 Pseudo-ionone Pseudo-ionone hydrate 
 
 CH 
 
 a-Ionone. 
 
 The pseudo-ionone hydrate, assumed as an intermediate product, 
 has been isolated (C. 1906, II. 723). The constitution of the two 
 ionones follows from their decomposition products : a-ionone gives, 
 on oxidation, j8j3-dimethyl-adipinic acid ; j8-ionone gives aa-dimethyl- 
 adipinic acid. 
 
 (7) HYDRO-AROMATIC CARBOXYLIC ACIDS. 
 
 Attached to the hydro-aromatic hydrocarbons, alcohols, amines, 
 aldehydes, and ketones are numerous hydro-aromatic carboxylic acids. 
 In addition to the simple carboxylic acids, oxy- and keto-carboxylic 
 acids are also known. S/M&IWIC and quinic acids belong to the first 
 class, while in the second class we find succino-succinic ester and other 
 important ketone-carboxylic esters, which are of great value in the 
 synthesis of the simple hydro-aromatic derivatives. 
 
 i. HYDRO- AROMATIC MONOCARBOXYLIC ACIDS. 
 
 A direct introduction of the carboxyl group into the nucleus of 
 hydro-aromatic substances can be brought about by the action of 
 CO 2 upon the cyclo-hexyl-magnesium haloids : 
 
 C.H U I -^-> C e H n C0 2 MgI -J*U C 6 H H C0 2 H. 
 
 But the transposition of halogen-cyclo-hexanes with KCN or Na 
 malonic ester either does not succeed at all, or is uneconomic, since 
 cyclo-hexenes are mostly formed and H haloids split off : 
 
 1-Methyl-cyclo-hexane-l-carboxylicacid m.p. 39, b.p. 234 (B. 40, 2069) 
 
 trans-Hexahydro-o-toluylic acid . . m.p. 51. b.p. 2 4 l0 lm 41 2679) 
 
 cis-Hexahydro-o-toluylic acid . . liquid, b.p. 236 / 
 
 Hexahydro-m-toluylic acid . . liquid, b.p. 240 
 
 a-Hexahydro-p-toluylic acid . . m.p. no , b.p. 246 
 
 /'-Hexahydro-p-tomylic acid . . liquid 
 
 2, 4-Hexahydroxylylic acid . . m.p. 77, b.p. 40 156 
 
 3, 4-Hexahydroxylylic acid . . liquid, b.p. 251 
 
 2, 6-Hexahydroxylylic acid . . m.p. 72. b.p. 251 
 
 3, 5-Hexahydroxylylic acid . liquid, b.p. 139 
 
 Hexahydro-cuminic acid m.p. 96. 
 
470 ORGANIC CHEMISTRY 
 
 Hexahydro - benzole Acids, hexamethylene - carboxylic acids, 
 
 naphthenic acids, have been obtained by the reduction of boiling amyl 
 or capryl solutions of benzoic acid and its homologues with metallic 
 sodium, or by reducing the solution of sodium benzoate with sodium 
 in an atmosphere of CO 2 (B. 24, 1865 ; 25, 3355). So far as present 
 experience warrants, they are isomeric and not identical (B. 27, R. 195, 
 197) with the " natural naphthenic acids " occurring in the oil which 
 issues from the earth in and about Baku. Just as fatty acids have been 
 prepared from malonic acids, so hexamethylene-monocarboxylic acids 
 have been obtained by heating hexamethylene- 1, i-dicarboxylic acids. 
 The latter bodies have been prepared synthetically. 
 
 The hexamethylene-carboxylic acids are weak acids. They are 
 reduced, when heated with hydriodic acid, to hexahydro-aromatic 
 hydrocarbons naphthenes, containing a like number of C-atoms in 
 the molecule. Hence they are also designated as naphthenic acids. 
 
 Hexahydro-benzoic acid, naphthenic acid CeH^.COaH, melting at 
 28 and boiling at 232, results from the reduction of benzoic acid, 
 A 2 -tetrahydro-benzoic acid (A. 271, 261), p-dimethyl-amido-benzoic 
 acid (B. 27, 2829), and cyclo-hexanol-i -carboxylic acid (B. 27, 1231) ; 
 also by heating hexamethylene- 1, i-dicarboxylic acid, and from chloro-, 
 bromo-, and iodo-cyclo-hexane with Mg and CO 2 (B. 35, 2688). The 
 calcium salt (C 7 H 11 O 2 ) 2 Ca+5H 2 O. The methyl ester boils at 182. 
 The ethyl ester boils at 194, and the amide melts at 185. The chloride 
 boils at 179 (B. 30, 1941). 
 
 The acids are prepared partly by the reduction of the corresponding 
 benzol-carboxylic acids, and partly by the action of Mg and CO 2 upon 
 the halogen-cyclo-hexanes. Hexahydro-o-toluic acid is formed from 
 2-methyl-cyclo-hexane-i, i-acetyl-carboxylic ester and I, i-dicar- 
 boxylic ester. The liquid cis-acid has been obtained by reduction of 
 its bromine substitution product. The liquid p-hexahydro-toluic 
 acid has been obtained from tropilidene-carboxylic acid (/. pr. Ch. 2, 
 57, 102 ; B. 32, 1167 ; C. 1899, n - 3 8 7)- 
 
 a-Monobromo-hexahydro-benzoic acid, melting at 63, and a-Mono- 
 bromo-hexahydro-p-toluic acid, melting at 71, are produced by acting 
 with bromine upon the chlorides of the corresponding hexahydro-acids. 
 From hexahydro-m-toluic acid two isomeric monobromo-derivatives 
 are obtained, melting at 118 and 142 respectively (B. 32, 1167). 
 
 a-Amido-hexahydro-benzoic acids have been obtained by action 
 of ammonium cyanide upon cyclo-hexanones and saponification of the 
 resulting a-amido-acid nitriles (B. 41, 2925). 
 
 a-Amido-hexahydro-benzoie acid C 5 H 10 > C(NH 2 )COOH, m.p. 335. 
 
 Hexahydro - anthranilic acid, o - amido - hexahydro - benzoic acid 
 NH 2 [2]C 6 H 10 .CO 2 H melts with decomposition at 274. It is formed 
 along with pimelic and hexahydro-benzoic acids in the reduction of 
 anthranilic acid with Na and amyl-alcohol (B. 27, 2470 ; A. 295, 187). 
 Hexahydro-m-amido-benzoic acid, m.p. 269, ethyl ester, b.p. u 123, 
 from m-amido-benzoic acid by reduction with Na and ethyl- or amyl- 
 alcohol, together with other bodies (A. 319, 324). Hexahydro-p- 
 dimethyl-amido-benzoic acid (B. 27, 2831). 
 
 Derivatives of o-amido-hexahydro-phenyl-acetic acid and propionic 
 acid result on oxidising dekahydro-quinolin compounds with potassium 
 permanganate. 
 
HYDRO-AROMATIC MONOCARBOXYLIC ACIDS 471 
 
 (CH 2 .CH 2 
 Octohydro-carbostyril c a H 10 j I melting at 151, is poisonous 
 
 (B. 27, 1472). Numerous further amido-cyclo-hexane-carboxylic acids 
 have been obtained from the oximes of the cyclo-hexanone- and cyclo- 
 hexenone-carboxylic ester by reduction with Na and alcohol (B. 40, 4167). 
 trans-Die thy 1-hexahydro-benzyl-amine-o-carboxylic acid (C 2 H 5 ) 2 N 
 CH 2 [2]C 6 H 10 COOH, m.p. 101, from o-diethyl-benzyl-amine-carboxylic 
 acid, by reduction with sodium and amyl-alcohol. By heating with 
 alkalies it is transposed into the more strongly basic, betain-like, oily 
 cis-acid, which is easily decomposed into diethyl-amine and o-methylol- 
 hexahydro-benzoie acid HOCH 2 .C 6 H 10 COOH, m.p. 112. This latter 
 
 <f*T_T V 
 CO/ ( A ' 3 ' 
 
 161). 
 
 For hexahydro-p-benzyl-amine- and p-diethyl-benzyl-amine-car- 
 boxylic acids, see A. 310, 189. 
 
 Tetrahydro-benzoic Acids can be obtained from the monoxy- 
 and monobromo-cyclo-hexane-carboxylic acids by splitting off H 2 O 
 or HBr, and also by the reduction of the benzoic acids and dihydro- 
 benzoic acids (B. 26, 457). 
 
 A^Tetrahydro-benzoie acid CH 2 <^2 2 2 !/ c - co 2 H . m -P- 2 9> b -P- 
 
 \V^/ il 2 V^ -H- 2 
 
 240, is formed from a-bromo-hexahydro-benzoic acid and from A 4 6 -di- 
 hydro-benzoic acid. Also from A 2 -tetrahydro benzoic acid by boil- 
 ing with alcoholic potash (B. 33, 3455). 
 
 A 2 -Tetrahydro-benzoic acid, benzolelnic acid C 
 
 CO 2 H, is a liquid boiling at 234 (A. 271, 234 ; B. 27, 2471). It is 
 formed from benzoic acid. 
 
 A 3 -Tetrahydro-benzoic acid CH^?? "^ ^NaiCOOH, m.p. about 
 
 \CH 2 C/H.J/ 
 
 13, b.p. 237, from 3- and 4-bromo-cyclo-hexane-carboxylic acid, 
 and by the action of CO 2 and Mg upon A 3 -bromo-cyclo-hexene (C. 
 1907, I. 1408 ; B. 43, 1039). 
 
 Of the tetrahydro-toluic acids, the following seven are known, which 
 are all obtained from the various bromo-methyl-cyclo-hexane-car- 
 boxylic acids by HBr, regenerative by means of quinolin, pyridin, etc. : 
 
 Ai-Tetrahydro-o-toluic acid CH 2 -CH 2 - C CO 2 H m ' p> 87V 
 A^Tetrahydro-m-toluic acid CH'-^CH^C CO H liquid b - p '" I5 ' 2 
 
 A^etrahydro-m-toluicacid , b. P . 
 
 . 20 
 
 /^TT . 
 
 A 3 -Tetrahydro-m-toluic acid H _ H _^ H 2 CO H b.p. 100 185.* 
 
 A-Tetrahydro-m-toluioacid C^. 
 
 k , _, CH,CH CH 2 -- CH 
 
 A^Tetrahydro-p-toluic acid CH 2 CH 2 __ C.CO 2 H m> P- I33 
 
 1 C. 1905, II. 766. a C. 1905, II. 767. 3 C. 1907, I. 1409. * C. 1909, I. 172 ; 
 6 C. 1905, II. 767. 6 A. 880, 159 ; C. 1906, II. 342. 7 C. 1909, I. 170. 
 
472 ORGANIC CHEMISTRY 
 
 The A 1 - and A 2 -tetrahydro-p-toluic acids and the A 2 -tetrahydro- 
 m-toluic acid have been split up into their optically active constituents 
 by means of their brucin and strychnin salts. Starting from A 2 -tetra- 
 hydro-m-toluic acid, sylvestrene and carvestrene (q.v.) have been built 
 up, and, starting from A 3 -tetrahydro-toluic acid, a-terpineol and di- 
 pentene (see below) (Per kin, jun.). A 1 -Tetrahydro-2, 6-xylylic acid, 
 m.p. 90 (C. 1899, II. 387). 
 
 a - Cyclo - geranic acid, 2, 6, 6-trimethyl-k?-tetrahydro-benzoic acid 
 
 CH2< \CH^C(CH 3 3J 2 / CHC 2H ' m ' p - Io6 ' k'P'i 1 I38 > is formed > together 
 with the isomeric j3-cyelo-geranic acid, m.p. 94, from geranic acid with 
 concentrated sulphuric acid ; its constitution is proved by its disintegra- 
 tion into a-acetyl-dimethyl-adipinic ester acid, and j3/2-dimethyl-adi- 
 pinic acid (B. 31, 828, 881 ; 33, 3713). A 3 -Cyclo-geranie acid, 2, 6, 6- 
 trimethyl-k?-tetrahydro-benzoic acid, m.p. (a) 76, (j8) 84, from oxy- 
 dihydro-cyclo-geranic acid, used for preparing A 3 -cyclo-citral (B. 41, 
 2066). From the cyano-hydrin of dihydro-iso-aceto-phorone we obtain 
 by saponification and elimination of H 2 O, a 3, 3, 5-trimethyl-tetra- 
 hydro-benzoic acid, m.p. 140, b.p. 16 154 (C. 1903, 1. 1245). 
 
 Dihydro-benzoic Acid s. A 1 - 3 - Dihydro-benzoie acid 
 CH^ - ^C.C0 2 H, m.p. 94, is produced in the oxidation of 
 
 dihydro-benzaldehyde, boiling at I2i-i22, with silver oxide. A 
 different dihydro-benzoic acid, melting at 73, is obtained from A 2 - 
 tetrahydro-benzoic acid dibromide (B. 24, 2622). Dihydro-cumie acid, 
 p-iso-propyl-dihydro-benzoic acid C 6 H 6 (C 3 H 7 )COOH, m.p. I3O-I33, 
 is formed when nopic acid, an oxidation product of j3-pinene, is boiled 
 with sulphuric acid (B. 29, 1926). 
 
 Hexa-, Tetra-, and Dihydro-phenyl Aliphatic Acids. Hexa- 
 hydro-phenyl-acetic acid C 6 H U .CH 2 .COOH, m.p. 33, b.p. 244, from 
 cyclo-hexyl-malonic acid or from hexahydro-benzyl chloride and iodide 
 with Mg and CO 2 (B. 40, 2067). Hexahydro-phenyl-propionie acid 
 C 6 H n .CH 2 .CH 2 COOH, b.p. n 143, from hexahydro-benzyl-malonic acid. 
 Amide, m.p. 120 (B. 41, 2676). 
 
 Tetrahydro-phenyl fatty acids are formed by detaching water from 
 the corresponding i, i-cyclo-hexanol fatty acids, or their esters, ob- 
 tained by the action of bromo-aliphatic esters and zinc upon cyclo- 
 hexanones. According to the dehydrating agents used, whether P 2 O 5 
 and HKSO 4 or acetic anhydride, we obtain either the ring-unsaturated 
 cyclo-hexene fatty acids or the isomeric cyclo-hexylidene fatty acids, 
 with semi-cyclic double-binding : 
 
 /CH 2 CH 2 \ (CH,.co) 2 o /CH 2 CH 2 \ /OH 
 
 CH2 \CH 2 -CH 2 / C ' CH - CO * H - CH2 \CH 2 -CH 2 / C \CH 2 C0 2 H 
 
 S0 4 HK | rw /CH 2 CH \ 
 
 On heating, both series of acids split off CO 2 , and change into alkyli- 
 dene-cyclo-hexanes (A. 365, 255). 
 
 From the easily synthesised cyclo-hexenones we immediately obtain 
 with zinc and bromo-acetic ester, instead of oxy-acids, cyclo-hexadiene- 
 carboxylic acids, which probably contain both double linkings in the 
 ring, and which, on heating, split off CO 2 and yield dihydro-benzol 
 derivatives (A. 323, 136). 
 
HYDRO-AROMATIC MONOCARBOXYLIC ACIDS 473 
 
 A^Cyelo-hexene-acetic acid, m.p. 38, on oxidation with KMnO 4 , 
 probably forms first an aldehyde-ketonic acid A^acetyl-cyclo-pentene 
 (B. 42, 145), and then A 2 -eyelo-hexene-aeetic acid, m.p. 12 ; see C. 1909, 
 II. 2146. 4-Methyl-A 1 -cyclo-hexene-acetic acid, m.p. 42 (C. 1909, I. 
 286). A^Cyelo-hexene-iso-butyric acid, m.p. 72. 
 
 Cyclo-hexylidene-acetic acid (CH 2 ) 5 : C : CH.CO 2 H, m.p. 92. The 
 4-methyl-eyclo-hexylidene-aeetic acid, m.p. 66 (inactive), has a special 
 theoretical interest, since, without containing an unsym. carbon atom, 
 it can be split up, by means of its brucin salts, into two optically active, 
 mirror-isomeric acids, m.p. 52, [a] D =+8i. The acids owe their 
 optical activity to the existence of an enantiotropic molecular structure. 
 In fact, the molecule of 4-methyl-cyclo-hexylidene-acetic acid, 
 
 CH 3 \ /CH 2 CH 2 \ C C /H CH 3\r C /CH 2 CH 2 \ ,-CH 3 
 
 HX \CH 2 CH,/ \CO 2 H HCO 2 / \CH 2 CH 2 / H ' 
 
 in which the links in the plane of the paper are indicated by solid lines, 
 and the links at right angles to the paper by dotted lines, contains no 
 plane of symmetry ; in other words, object and mirror image can be 
 brought to coincide (A. 371, 180 ; cp. also Vol. I.). 
 
 1, 3-Methyl-cyclo-hexadiene-acetie acid CH 3 C 6 H 6 CH 2 CO 2 H, m.p. 
 171, from 3-methyl-cyclo-hexenone. 
 
 1, 3, 5-Dimethyl-cyclo-hexadiene-acetic acid (CH 3 ) 2 C 6 H 5 CH 2 CO 2 H, 
 m.p. 151, b.p. 15 170, from 3, 5-dimethyl-cyclo-hexenone. 
 
 Addendum. Hexahydro-phenyl-acetylene-carboxylic acids : 
 
 Hexahydro-phenyl-propiolie acid C 6 H n C ; C.CO 2 H, b.p. 16 139, from 
 hexahydro-phenyl-acetylene sodium and CO 2 (C. 1909, II. 208). Hexa- 
 hydro-phenyl-tetrolie acid C 6 H n .CH 2 .C ; CO 2 H, m.p. 75, from cyclo- 
 hexyl-allylene (C. 1910, II. 387). 
 
 Hexahydro - oxy-benzoic A cids. a - Oxy - cyclo - hexane - carboxylic 
 acid, a-oxy-hexahydro-benzoic acid, cy do-he xanol-i-carboxylic acid 
 CH 2 <^ 2 2 Nc<^ 2 , melting at 106, is formed when cyclo- 
 
 hexanone, in ether, is treated with prussic and hydrochloric acids 
 (C. 1909, II. 1869). a-Oxy-3-methyl-cyclo-hexane-carboxylic acid, 
 b.p. 12 164 ; see C. 1907, I. 1407. 2-, 3-, and 4-Oxy-cyclo-hexane-car- 
 boxylic acids are formed by reduction of the oxy-benzoic acids or the 
 cyclo-hexane-carboxylic acids with sodium and alcohol. They usually 
 occur in cis-trans-isomeric forms, out of which the cis-forms of 3- and 
 4-oxy-cyclo-hexane-carboxylic acids pass easily into lactones with 
 elimination of water. 
 
 Hexahydro - salicylic acid, (j5-) hexahydro -o- oxy-benzoic acid 
 CH 2 /CH 2 .CH(OH)\ CR COaH) m.p. in , results when nitrous acid acts 
 
 upon hexahydro-anthranilic acid and by reducing jS-keto-hexamethylene- 
 carboxylic ester (B. 27, 2472, 2476). 
 
 Hexahydro-m-oxy-benzoic acid, m.p. cis- 132, trans- 120, is ob- 
 tained by the reduction of m-oxy-benzoic acid with sodium in ethyl 
 alcohol (B. 29, R. 549 ; C. 1907, I. 1408). 
 
 Hexahydro-p-oxy-benzoie acid, m.p. 121, from i, 4-cyclo-hexanone- 
 carboxylic acid (C. 1904, I. 1082). 
 
 2-, 4-, 5-, and 6-Methyl-3-oxy-eyclo-hexanone-carboxylie acids have 
 been obtained from the corresponding oxy-toluic acids (C. 1910, 1. 270). 
 
474 ORGANIC CHEMISTRY 
 
 3-Methyl-oxy-eyclo-hexane-carboxylic acids, cis- m.p. 140, trans- 
 m.p. 116, from the corresponding ketonic acids (C. 1909, I. 172). 
 
 4-Methyl-4-oxy-cyclo-hexane-carboxylic acids, m.p. 153, lactone 
 m.p. 70, from i, 4-cyclo-hexanone-carboxylic ester and CH 3 MgI (C. 
 1904, I. 1604). 
 
 Oxy-dihydro-cyclo-geranic acid, S-oxy-cyclo-geraniolane-carboxylic 
 acid CH(OH)/CH^H(CH3)\ C H .co 2 H, cis- (a) m.p. 145, trans- (a) 
 
 \U1 2 U(Uil 3 ) 2 / 
 
 m.p. 155, lactone m.p. 58, cis- (j3) m.p. 158, trans- (]8) m.p. 38, is 
 formed in two stereo-isomeric pairs each by reduction of iso-phorone- 
 carboxylic ester with Na and alcohol. By the action of dehydrating 
 agents, all of these pass, more or less easily, into A 3 -cyclo-geranic acid 
 (A. 366, 151). 
 
 3, 5, 5-Trimethyl-hexahydro-salieylic acid, m.p. 180, b.p. 10 204, 
 from trimethyl-j8-keto-hexamethylene-carboxylic acid (C. 1903, II. 78). 
 
 Hexahydro-dioxy-benzoic acid is obtained from AMetrahydro- 
 benzoic dibromide (A. 271, 280). 
 
 Dihydro-shikimic acid, hexahydro-trioxy-benzoic acid (HO) 3 C 6 H 8 . 
 CO 2 H, m.p. 175, results when shikimic acid is reduced with sodium 
 amalgam. 
 
 Quinic acid, hexahydro-tetraoxy-benzoic acid (HO) 4 .C 6 H 7 .CO 2 H, 
 m.p. 162, optically active, is present in cinchona bark, in coffee beans, 
 in bilberry, and, in small quantities, in hay and sugar-beet. It is ob- 
 tained as a secondary product in the preparation of quinine, by ex- 
 tracting the quinia bark. When its calcium salt has been purified by 
 recrystallisation, the acid is liberated by oxalic acid. Upon distilla- 
 tion, the acid breaks down into phenol, hydroquinone, benzoic acid, 
 and salicyl-aldehyde. When boiled with water and lead peroxide it 
 changes to hydroquinone, while manganese peroxide and sulphuric 
 acid convert it into quinone. Proto-catechuic acid is formed when it 
 is melted with caustic potash or soda. Ferments decompose calcium 
 quinate into proto-catechuic acid. If air is excluded while the fermen- 
 tation takes place, the products are formic acid, acetic acid, and pro- 
 pionic acid. Quinic acid is reduced by hydriodic acid to benzoic acid. 
 The calcium salt has the formula (C 7 H n 6 ) 2 Ca+ioH 2 O. The methyl 
 ester, m.p. 120. Amide, m.p. 132. Tetracetyl-ethyl ester C 6 H 7 
 (O.COCH 3 ) 4 .CO 2 C 2 H 5 melts at 135 (B. 22, 1462). 
 
 Inactive quinic acid is produced when its lactone, quinide, is boiled 
 with milk of lime. Calcium salt (C 7 H 11 O6) 2 Ca+4H 2 O. 
 
 Quinide C 7 H 10 O 5 , m.p. 198, optically inactive, results upon heating 
 ordinary optically active quinic acid to 22O-240 (B. 24, 1296). 
 
 Dioxy-dihydro-shikimic acid, hexahydro-pentaoxy-benzoic acid 
 (HO) 5 C 6 H 6 .CO 2 H, melts at 156 with the elimination of water. It is 
 optically inactive, and is obtained from the bromo-lactone, melting at 
 235, which is formed in the action of baryta water (B. 24, 1294) upon 
 dibromo-shikimic acid. 
 
 Shikimic acid, trioxy-tetrahydro-benzoic acid (HO) 3 C 6 H 6 .CO 2 H, 
 m.p. 184, occurs in the fruit of Illicium religiosum. Its transposition 
 products, dihydro- and dioxy-dihydro-shikimic acids, have been 
 previously described. 
 
 Hexahydro-oxy-phenyl Fatty Acids. 1, 1-Cyclo-hexanol-aeetic acid 
 C $ H lo : C(OH).CH 2 CO 2 H, m.p. 63. 1, 4-Methyl-cyclo-hexanol-acetic 
 
HYDRO-AROMATIC MONOCARBOXYLIC ACIDS 475 
 
 acid CH 3 .C 5 H 9 : C(OH).CH 2 .CO 2 H, a-acid, m.p. 141, 0-acid, m.p. 90. 
 1, 4-Methyl-cyclo-hexanol-propionic acid CH 3 .C 5 H 9 : C(OH).CH(CH 3 ). 
 CO 2 H, m.p. 110. These esters are produced by condensation of 
 cyclo-hexanones with bromo-aliphatic esters and zinc (A. 360, 26 ; 365, 
 261). 
 
 Hexahydro-mandelic acid C 6 H n .CH(OH).COOH, m.p. 166, from 
 hexahydro-phenyl-acetaldehyde-cyano-hydrin (B. 41, 2677). 
 
 Cyelo-hexyl-glycidic esters like [CH 2 ] 5 : C.O.CH.CO 2 C 2 H 5 , b.p. 17 128, 
 
 and [CH 2 ] 5 : C.O.(':(CH3)CO 2 C 2 H 5 , b.p.^ 155, are formed by condensa- 
 tion on cyclo-hexanones and chloracetic esters or chloro-propionic ester 
 with sodium ethylate. 
 
 The glycidic acids produced by saponification easily break up into 
 CO 2 and aldehydes or ketones (C. 1906, I. 1423 ; 1907, II. 332). 
 
 Keto-hydro-monocarboxylic Acids, I, 2-cyclo-hexanone-carboxylic 
 acids and their esters are produced (i) by cyclic aceto-acetic-ester 
 condensation of pimelinic ester and its alkyl-substitution products by 
 means of sodium (A. 317, 27) ; (2) from cyclo-hexanone oxalic esters, 
 the condensation products of the cyclo-hexanones with oxalic ester, 
 on heating with rejection of carbon monoxide (A. 350, 211) ; (3) by 
 the action of sodium amide and CO 2 upon cyclo-hexanones in ether 
 solution (C. 1910, II. 1378). 
 
 1, 2-Cyelo-hexanone-earboxylic acid CH 2 <^*^^>cH.CO 2 H, m.p. 
 
 80, with rejection of CO 2 . The ethyl ester boils at 107 (n mm.), 
 and is formed by the above methods. Like the j3-keto-pentamethylene- 
 carboxylic ester, it is a cyclic analogue of aceto-acetic ester. It is 
 broken up by dilute sulphuric acid into cyclo-hexanone, and by boiling 
 with alcoholic potash into pimelinic acid. With sodium alcoholate 
 and methyl iodide it gives 1-methyl-l, 2-cyclo-hexanone-carboxylic 
 ester, b.p. 108. It is split up by alcoholic potash to a-methyl-pime- 
 linic acid ; with ammonia the I, 2-cyclo-hexanone-carboxylic ester 
 produces tetrahydro-anthranilic ester C 6 H 8 (NH 2 )CO 2 R, m.p. 74 (A. 
 317, 93). Special interest attaches to the 4-methyl-l, 2-cyclo-hexa- 
 none-carboxylic ester CH 3 .CH<^ 2 ~^ 2 V HCO * C 2 H 5> b.p. 13 123, from 
 
 NL/xlj L/U / 
 
 j3-methyl-pimelinic ester or I, 3-methyl-cyclo-hexanone-oxalic ester ; 
 with sodium and iso-propyl iodide it gives 4-methyl-l-iso^propyl-l, 2- 
 cyclo-hexanone-carboxylic ester CH 3 CH<(^^^ 2 )>c<(^ R , b.p. 14 
 
 146, from which, by saponification with dilute sulphuric acid, methone 
 is formed (A. 342, 198). 
 
 3, 5, 5-Trimethyl-l, 2-cyclo-hexanone-carboxylic acid, m.p. 111 
 with decomposition, is formed from dihydro-iso-aceto-phorone by 
 treatment with CO 2 and Na in ether (C. 1902, II. 1372). 
 
 1, 3-Cyclo-hexanone-carboxylic acid CH 2 <(^-*\CH.co z tt, m.p. 
 
 XL-rlj.Urlj/ 
 
 74, from tetrahydroxy-terephthalic acid by heating to 115 or by 
 boiling with water, or by oxidation of m-oxy-hexahydro-benzoic acid 
 in the form of its ester "with sodium bichromate (B. 29, R. 550 ; C. 
 1910, I. 533). 
 
 1, 4-Cyclo-hexanone-carboxylic acid 
 
476 ORGANIC CHEMISTRY 
 
 m.p. 68, is formed synthetically by the action of acetic anhydride 
 upon a, y, -pentane-tricarboxylic acid and subsequent distillation. 
 The acid is useful as a starting-point for the synthesis of a-terpineol 
 and dipentene (C. 1904, I. 1082). 3-Methyl-l, 4-cyclo-hexanone- 
 carboxylic acid, m.p. 94 ; see C. 1909, I. 172. 
 
 Numerous y-keto-carboxylic acids have been obtained by reducing 
 the corresponding i, 4-cyclo-hexanone-carboxylic esters with hydrogen 
 and colloidal palladium (B. 42, 1627). 2-Methy 1-1, 4-cyclo-hexanone- 
 carboxylic ethyl ester, b.p. 15 128, dihydro-iso-phorone-carboxylic ester, 
 occurs in two cis-trans-isomeric forms : a-form, m.p. 44, b.p. 9 125 ; 
 /J-form, liquid, b.p. 12 137 ; and the free acids, a-form, m.p. 127, 
 j8-form, m.p. 119, are produced by oxidation of the oxy-dihydro- 
 cyclo-geranic acids, passing into the trans-forms of these acids, by 
 reduction with sodium and alcohol. 
 
 1-Acetyl-cyclo-hexane-carboxylic ester ci 
 
 b.p. 24i-245, is formed from i, 5-dibromo-pentane and sodium aceto- 
 acetic ester ; on boiling with alcoholic potash it yields hexahydro- 
 aceto-phenone (B. 40, 3945). Similarly, we obtain 2-methyl-l-acetyl- 
 cyclo-hexane-carboxylic ester from i, 5-dibromo-hexane and sodium 
 aceto-acetic ester (B. 21, 737). 
 
 Hexahydro-benzoyl-acetic ester CpHij.CO.CH^COaCgHg, b.p. 18 136, 
 from hexahydro-benzoic ester, acetic este** and sodium (C. 1908, II. 
 1687). 
 
 Cyclo-hexyl-aceto-acetic ester C 6 H n CH(COCH 3 )CO 2 C 2 H 5 , b.p. 14 
 126, obtained in small quantities from iodo-cyclo-hexane and sodium- 
 aceto-acetic ester (B. 42, 2232). 
 
 A 6 - 1, 2 - Cyclo - hexenone - carboxylic acid, dihydro - salicylic acid 
 CH/^2 C0\ c C02H) m.p. 128, its ethyl ester, b.p. 12 103 
 
 \(_/.H.o OAT.-/ 
 
 cyclo-hexanone-carboxylic ester by bromination and rejection of HBr 
 from a-bromo-i, 2-cyclo-hexanone-carboxylic ester, b.p. 13 144, by 
 boiling with aniline. On heating with soda-lime the acid breaks up 
 into CO 2 and A 2 -cyclo-hexanone (/. pr. Ch. 2, 80, 495). 
 AM, 4-Cyclo-hexenone-carboxylic esters like 
 
 are obtained by the action of sodium ethylate upon alkylidene-bis- 
 aceto-acetic ester with rejection of one carboxyl group. They contain 
 the group of glutaconic ester (Vol. I.), and can therefore, like the latter, 
 be alkylated with sodium alcoholate and alkyl iodide. The esters occur 
 in a neutral form insoluble in alkali, and an acid form soluble in alkali. 
 By means of sodium ethylate, the former may be transformed into the 
 latter. Reduction with hydrogen and colloidal palladium produces 
 i, 4-cyclo-hexanone-carboxylic esters. The cyclo-hexenone-carboxylic 
 acids easily break up into CO 2 and A 2 -cyclo-hexenones. 
 
 2-Methyl-A 2 -l,4-cyclo-hexenone-carboxylie ester 
 
 C <CH^>CH 3 C0 2 .C 2 H 6 ' b 'P' '55. from methylene iodide, and 
 sodium-aceto-acetic ester, or by the action of sodium ethylate upon 
 methylene-bis-aceto-acetic ester (B. 30, 639 ; 41, 2943) ; by addition 
 of bromine and rejection of 2HBr it yields o-methyl-p-oxy-benzoic 
 acid (B. 38, 969). 
 
 2, 6-Dimethyl-A 2 -l, 4-cyclo-hexenone-carboxylic ester, b.p. 140, 
 
HYDRO-AROMATIC DICARBOXYLIC ACIDS 477 
 
 from ethylidene-bis-aceto-acetic ester (A. 342, 344). Iso-phorone-car- 
 boxylic ester co <(C^CO t C t H tl b.p. 10 i36-i40, is formed 
 
 by attaching sodium-aceto-acetic ester to iso-propylidene-aceto-acetic 
 ester. On saponification, iso-phorone is produced ; and, on reduction 
 with sodium and alcohol, a mixture of various isomeric oxy-dihydro- 
 cyclo-geranic acids. 
 
 4-Iso-propylidene-l, 2-cyelo-hexanone - carboxylie ester 
 
 * 2 ~ nas been obtained, by cyclic aceto-acetic 
 
 ester condensation, from y-iso-propylidene-pimelinic ester (C. 1907, II. 
 1976). 
 
 5, 5-Dimethy 1-A 1 -!, 3-cyclo-hexenone-acetic ester 
 
 b . p . 22 I7I .. see C . I909 , I. 8 53 . 
 
 2. HYDRO-AROMATIC DICARBOXYLIC ACIDS. 
 
 Hexahydro-dicarboxylic Acids. These acids, depending upon the 
 position of the carboxyl groups with reference to one another, show the 
 behaviour of dialkyl-malonic acids, sym. dialkyl-succinic acids, sym. 
 a-dialkyl-glutaric acids, and sym. a-dialkyl-adipic acids. 
 
 1, 1-Dicarboxylic ester and 2-methyl-cyclo-hexane-l, 1-dicarboxylic 
 ester have been made by the action of sodium-malonic ester upon 
 pentamethylene bromide and methyl-pentamethylene bromide. The 
 free acids, when heated, split off CO 2 and become hexahydro-benzoic 
 acid and hexahydro-o-toluic acid. 2-Methyl-eyclo-hexane-l, 1-dicar- 
 
 boxylic acid CH,<^^^^^>C(CO t H) t meltsati4^ e . Cyclo-hexane- 
 
 dicarboxylic acid and its esters appear not to have been isolated as yet 
 (B. 21, 735 ; 26, 2246). 
 
 Cyclo-hexane-malonic acid ethyl ester C 6 H n .CH(CO 2 C 2 H 5 ) 2 , b.p. 20 
 164, and cyclo-hexyl-cyanic acid ester, b.p. 23 158, are obtained in 
 small quantity from bromo- and iodo-cyclo-hexane with sodium-malonic 
 ester and cyan-acetic ester respectively. 
 
 Cyclo-hexyl-malonic acid, m.p. 177, breaks up, on heating, into 
 CO 2 and hexahydro-phenyl-acetic acid (C. 1905, II. 1430). Hexahydro- 
 benzyl-malonic ester C 6 H n .CH 2 .CH(CO 2 C 2 H 6 ) 2 , b.p. 12 i45-i55. 
 
 Hexahydro-phthalic Acids. A. Baeyer's theory (B. 23, R. 577), 
 based upon the spatial representations of van Hoff as to the union of 
 the C atoms, predicts the possibility of geometrically isomeric hexa- 
 hydro-phthalic acids. The latter isomerism is due to the different 
 positions occupied by the carboxyls relatively to the plane of the 
 hexamethylene ring ; hence the isomerides are termed cis- and trans- 
 forms. 
 
 eis-Hexahydro-o-phthalic acid, i, z-hexamethylene-dicarboxylic acid 
 C 6 H 10 (CO 2 H 2 ) melts at 192, and its anhydride melts at 32 and boils 
 at 145 (18 mm.) ; the trans-hexahydro-o-phthalie acid melts at 215, 
 and its anhydride at 140. They are produced together when A 1 -tetra- 
 hydro-o-phthalic acid is reduced. The trans-acid is also obtained by 
 the oxidation of o-methylol-hexahydro-benzoic acid. The cis-acid is 
 more soluble in water than the trans-acid. The anhydride of the latter 
 is converted by continuous heating at 2io-220 into the anhydride of 
 
478 ORGANIC CHEMISTRY 
 
 the cis-acid (A. 258, 214). The trans-acid has been broken up by 
 means of its quinine salt into optically active components, d- and 
 1-trans-hexahydro-phthalic acid [a] D2 -hi8-2 and 18-5, m.p. 179- 
 183. Anhydride, m.p. 164 (B. 32, 3046). 
 
 Hexahydro-iso-phthalie acids are produced in the reduction of iso- 
 phthalic acid and when I, I ,3, 3-hexamethylene-tetracarboxylic acid 
 is heated to 200-22O. The calcium salt of the cis-acid is more 
 sparingly soluble. The cis-acid, melting at 162, when heated to 180 
 with hydrochloric acid, changes in part to the trans-acid, melting at 
 1 88. Both acids, with acetyl chloride, yield the acid anhydride, 
 melting at 119 (B. 26, R. 721). 
 
 Hexahydro-terephthalic acids result on reducing the hydro-bromides 
 of the tetrahydro-terephthalic acids in glacial acetic acid with zinc 
 dust, as well as upon heating hexamethylene-i, i, 4, 4-tetracar boxy lie 
 acid to 200-220. In the latter case the trans-acid, melting at 200, 
 predominates. The cis-acid, melting at 161, is also converted into 
 it when heated with hydrochloric acid to 180. As regards solubility, 
 these three pairs of hexahydro-phthalic acids reduce fumaric and 
 maleic acids. They are also convertible one into the other in like 
 manner. They have also been distinguished, one from the other, as 
 malelnold and fumaroid modifications. 
 
 a-Bromo-substitution products of these acids have also been 
 prepared from the acid chlorides, by treatment with bromine. Bromo- 
 substituted hexahydro-carboxylic acids have also been obtained by the 
 addition of hydrogen bromide and bromine to the corresponding tetra- 
 and dihydro-carboxylic acids. 
 
 Hexahydro-homo-iso-phthalie acid C 6 H iq [i, 3](COOH)(CH 2 COOH), 
 m.p. 158, by reduction of homo-iso-phthalic acid, gives, on distilling 
 
 its calcium salt, a dicyclic ketone CH 22 .^^- ^. cp 
 
 Nv^Jtio'^-tjL - V-/-H.O 
 
 camphor (B. 36, 3610). 
 
 Tetrahydro - diearboxylic Acids, Tetrahydro-o-phthalic Acids 
 Depending upon the point of double union there are, theoretically 
 speaking, four structurally isomeric bodies. The two modifications in 
 which neither of the two CO 2 H-groups is attached to a doubly com- 
 bined C atom permit of a stereo-isomeric modification of each. 
 
 CH 2 .CH 2 .C.CO 2 H 
 
 A^Tetrahydro-o-phthalic acid I , melting at 120, 
 
 CH 2 .CH 2 .C.C0 2 H 
 
 and its anhydride at 74, is formed when hydro-pyro-mellitic acid is 
 distilled. Potassium permanganate decomposes it into adipic acid 
 (A. 166, 346; 258, 203). 
 
 /-TT /~>TT _ -p PO TT 
 
 A 2 -Tetrahydro-o-phthalic acid \ *' ~ \' * , melting at 21 5, 
 
 CH 2 -CH 2 CH.C0 2 H 
 
 and its anhydride at 78, has been obtained by the decomposition of 
 sedanonic acid, an o-valeryl-tetrahydro-benzoic acid obtained from 
 celery oil (B. 30, 503). It is also formed on boiling the A*-acid with 
 caustic potash, when the double union is shifted, and by the reduction 
 of phthalic acid or A 2 ' 6 -dihydro-phthalic acid together with trans-A 4 - 
 
 ^ CH CH 2 CH.C0 2 H 
 tetrahydro-o-phthalie acid || | ' , melting at 216, and 
 
 CH . CH 2 . CH.C0 2 H 
 its anhydride at 140. Acetyl chloride separates it from A 2 -acid. 
 
HYDRO-AROMATIC DICARBOXYLIC ACIDS 479 
 
 This reagent converts it alone into its corresponding anhydride 
 (A. 258, 211). 
 
 cis-A 4 -Tetrahydro-o-phthalic acid melts at 174. It is produced 
 when the A 2 ' 4 -dihydro-acid is reduced, as well as from its anhydride, 
 melting at 58. The latter anhydride is formed when the anhydride 
 of the trans- A 4 -acid is heated (A. 269, 202). 
 
 Tetrahydro-iso-phthalie Acids. The three theoretically possible 
 structure-isomeric acids are all known, one of them even occurring in 
 a stereo-isomeric modification (C. 1905, I. 1320 ; II. 474). 
 
 A^A^Tetrahydro-iso-phthalic acid 2 ^ZH~Cii 2 ' m ' p - 
 1 68, is obtained by the reduction of iso-phthalic acid with sodium 
 amalgam at 45. Its anhydride, m.p. 78, is also formed from the 
 A 3 - and A 4 -acid by heating with acetic anhydride. 
 
 A 3 -Tetrahydro-iso-phthalic acid H 2C '^^ z ~ ^ C 2 ' H > m -P- 244, 
 from the A 2 - and A 4 -acid on boiling with concentrated potash. 
 
 cis-A 4 -Tetrahydro-iso-phthalic acid H aC '^3^ CH C 2H ' m ' p ' 
 165, is formed together with the A 2 -acid by reducing iso-phthalic acid 
 with sodium amalgam. On heating with HC1 to 170, it is converted 
 into trans-AMetrahydro-iso-phthalic acid, m.p. 226. 
 
 Tetrahydro-terephthalic Acids are theoretically possible in two 
 structurally isomeric forms, depending upon the position of the double 
 union ; one of these can occur in two stereo-isomeric modifications. 
 
 A 2 -Tetrahydro-terephthalic acid CO.H.CH/^ \CH.co 2 .H is 
 
 produced in two isomeric modifications by the reduction of A 1 ' 3 - 
 and A 1 ' 5 -dihydro-terephthalic acids. The trans-acid melts at about 
 300. The cis-acid melts at 150. The latter is much more readily 
 soluble in water than the former. Potassium permanganate oxidises 
 them to succinic acid. Boiling sodium hydrate changes the two acids, 
 like /?y-hydro-muconic acid, into ajS-hydro-muconic acid. 
 
 A^Tetrahydro-terephthalic acid co 2 H.CH/ 2 CE V.CO 2 H melts 
 
 \CH 2 CH 2 / 
 
 above 300 and sublimes (A. 258, 7). 
 
 Dihydro-dicarboxylic Acids. Dihydro-o-phthalic acids are possible, 
 according to the position of the double union, in six structurally isomeric 
 forms, one of which can occur in two stereo-isomeric modifications. 
 
 CH.CH 2 .C.CO 2 H 
 
 A 1 ' 4 -Dihydro-o-phthalic acid || , melting at 153 (its 
 
 CH.CH 2 .C.CO 2 H 
 
 anhydride at 134), is produced on boiling A 2 4 -dihydro-phthalic 
 acid with acetic anhydride (A. 269, 204). 
 
 CH.CH 2 .CH.CO 2 H 
 
 A 2 - 4 -Dihydro-o - phthalic acid \\ , melting at 179 (its 
 
 CH.CH.C . C0 2 H 
 
 anhydride at 103), is produced when the acid is acted upon in 
 the cold with acetic anhydride. 
 
 The acid is produced, further, on boiling A 2j6 -dihydro-o-phthalic 
 acid dihydro-bromide with methyl-alcoholic potash. 
 
 C"T~f fT-f C CO TT 
 
 A 2 ' 6 -Dihydro-o-phthalic acid I melts at 215, and 
 
 CH 2 .CH : C.C0 2 H 
 its anhydride at 83. The acid results by reducing phthalic anhydride 
 
480 ORGANIC CHEMISTRY 
 
 with sodium amalgam in alkaline solution, and by boiling the A 2 - 4 - and 
 A 3 5 -acid with sodium hydrate (see also B. 27, 3185). 
 
 CH : CH.CH.CO 2 H 
 
 trans-A 3 ' 5 -Dihydro-phthalic acid I , melting at 210. 
 
 CH : CH.CH.C0 2 H 
 
 is produced by reducing phthalic anhydride with sodium amalgam in 
 acetic acid solution. The acid has been split up into its optically 
 active components by means of its strychnin salt. On passing into 
 the A 2)6 -acid by boiling with sodium hydrate, or into the cis-A 3 > 5 -acid 
 by heating with acetic anhydride, the optical activity disappears, the 
 resulting acids containing no unsym. carbon atom (C. 1907, I. 565). 
 
 cis-A 3 > 5 -Dihydro-phthalie acid melts at 174. Its anhydride, melt- 
 ing at 99, is formed when the trans-A 3 5 -acid is acted upon with acetic 
 anhydride. 
 
 Dihydro-terephthalic Acids. Depending upon the points of double 
 union, there are four possible structural isomerides. One of these, the 
 A 2 5 -acid, appears in two stereo-isomeric forms. All the modifications 
 are known. 
 
 A^-Dihydro-terephthalie acid CO Z H.C<^H -C^: \ c . C o 2 H is pro- 
 
 \L/rl 2 .Orl 2 / 
 
 duced on digesting a, c^-dibromo-hexahydro-terephthalic acid and 
 A 2 -tetrahydro-terephthalic acid dibromide with alcoholic potash 
 (A. 258, 23). The dimethyl ester melts at 85. 
 
 A^-Dihydro-terephthalic acid CO 2 H.c<^H.c^\ c CO2H is formed 
 
 by reducing terephthalic acid with sodium amalgam, by boiling the 
 isomeric dihydro-terephthalic acids with sodium hydrate (A. 251, 272), 
 and by reducing p-dichloro-A 1>4 -dihydro-terephthalic acid, the result 
 of the action of PC1 6 upon succinyl-succinic ester, with sodium amalgam 
 (B. 22, 2122). 
 
 The dimethyl ester melts at 130. It condenses by means of its 
 CH 2 groups with oxalic ester and with benzaldehydes in the presence 
 of sodium alcoholate to terephthalic acid derivatives : phthalide-dicar- 
 boxylic acid, the lactone of the acid (HOOC) 2 C 6 H 3 CH(OH)COOH, and 
 benzyl-terephthalic acid (HOOC) 2 C 6 H 3 CH 2 C 6 H 3 (B. 36, 842). 
 
 A 1 ' 5 -Dihydro-terephthalie acid results on boiling trans-A 2 ' 5 -dihydro- 
 terephthalic acid with sodium hydroxide ; the dimethyl ester resinifies 
 on exposure to the air (A. 258, 18). 
 
 A 2 ' 5 -Dihydro-terephthalie acids co 2 H.CH/ : ^\CH.CO,H, cis- 
 
 acid and trans-acid, are formed in the reduction of terephthalic acid. 
 See also A 1 5 -dihydro-terephthalic acid. The trans-diphenyl ester melts 
 at 146. The cis-dimethyl ester melts at 77 (A. 258, 17). This ester 
 breaks up into terephthalic and hexahydro-terephthalic esters, on 
 heating in a CO 2 atmosphere in the presence of palladium black 
 (B. 36, 2857). 
 
 Oxy- and k e t o - h y d r o - benzol - dicarboxylic Acids. a-Oxy- 
 
 hexahydro-iso- phthalic acid c ^^^)^<^ is obtained 
 from m-keto-hexahydro-benzoic acid by the action of prussic acid 
 and hydrochloric acid (B. 22, 2186 ; C. 1904, I. 1082). 
 m-Dioxy-hexahydro-iso-phthalie acid CH 2 / 
 
 \v 
 
HYDRO-AROMATIC DICARBOXYLIC ACIDS 481 
 
 melts with decomposition at 217. Its anhydride melts at 175. The 
 acid is obtained from its nitrile, the product of the addition of prussic 
 acid to dihydro-resorcinol (A. 278, 49). 
 
 a, a^Dioxy-hexahydro-terephthalic acid 
 
 is formed when its dinitrile, melting with decomposition at 180, is 
 boiled. This dinitrile results on adding prussic acid to p-diketo-hexa- 
 methylene with hydrochloric acid (B. 22, 2176). 
 
 Hexahydro-2,5-dioxy-terephthalie acid C 6 H 8 (OH) 2 (COOH) 2 , ethyl 
 ester, m.p. 136, formed besides tetrahydro-p-dioxy-terephthalie acid, 
 ester, b.p. 14 219, by reduction of succinyl-succinic ester with sodium 
 amalgam. The dioxy-hexahydro-terephthalic ester, on distillation, 
 partly splits off H 2 O and passes into A 1 ' 4 -dihydro-terephthalic acid 
 ester (B. 33, 390). 
 
 A 1 -Tetrahydro-2-oxy-terephthalic acid, or 2-keto-hexamethylene-i, 4- 
 dicarboxylic acid 
 
 .CO.H, or C 
 
 results from the reduction of oxy-terephthalic acid. When heated to 
 60 with water, it splits off carbon dioxide and becomes m-keto-hexa- 
 hydro-benzoic acid, the oxime of which is obtained from tetrahydro- 
 oxy-terephthalic acid by means of hydroxylamine hydrochloride 
 (B. 22, 2187). 
 
 Keto-tetrahydro-benzol-polycarboxylic esters and m-diketo-hexahydro- 
 benzol-carboxylic esters, or hydro-resorcylic esters, have been prepared 
 synthetically in great numbers from I, 5-diketone- and S-ketone- 
 carboxylic esters, respectively, by the elimination of water or of alcohol. 
 A series of keto-R-hexenes, dihydro-resorcins, tetrahydro-benzols, 
 dihydro-benzols, etc., has been built up from these bodies as the 
 foundation substances. 
 
 Several alkylidene-bis-aceto-acetic esters are to be regarded as 
 cyclo-hexanolone-dicarboxylic esters. 
 
 Cyelo-hexanone-2, 4-dicarboxylic ethyl ester 
 
 , ,-tricar- 
 
 boxylic ester by cyclic aceto-acetic ester condensation (C. 1907, I. 344). 
 Cyelo-hexanone-2, 6-dicarboxylic methyl ester 
 
 CH 2 /^; H 2 CH >cc 2 3 , keto-form melting at 125, enol-form liquid 
 
 \CH 2 CH - CO 2 Cri3 
 
 from pentane-cu-tetracarboxylic ester, with sodium ethylate and elimi 
 nation of carbonic acid ester (H. Meerwein). 2-Methyl-cyclo-hexa- 
 none-2, 6-dicarboxylic ethyl ester, b.p. 10 160, see A. 350, 214. 
 
 Succino-succinic acid co 2 H.CH/^.CH 2 \ CH COaH results upon 
 
 \UH 2 .CU/ 
 
 saponifying its diethyl ester with a calculated amount of normal 
 sodium hydroxide, and by treating 2, 5-dioxy-terephthalic ester with 
 sodium amalgam. The dry acid breaks down into two molecules of 
 carbon dioxide and p-diketo-hexamethylene when heated to 200 
 (B. 22, 2168). 
 
 Succino-succinic diethyl ester, m.p. 126, is produced by the con- 
 densation of two molecules of succinic ester through the action of 
 potassium, sodium, or sodium ethylate upon succinic ester (A. 211, 
 VOL. II. 2 I 
 
482 ORGANIC CHEMISTRY 
 
 306) or bromaceto-acetic ester (A. 245, 74), as well as by the interaction 
 of silver cyanide and iodo-aceto-acetic ester (A. 253, 182), and by the 
 reduction of 2, 5-dioxy-terephthalic ester with zinc and hydrochloric 
 acid (B. 19, 432). 
 
 Succino-succinic ester behaves like phloro-glucin. It also mani- 
 fests many reactions of a ketone, corresponding to formula I. of 2, 5- 
 diketo-hexamethylene-carboxylic ester ; whereas it also conducts 
 itself like a phenol, corresponding then to formula II. of 2, 5-dioxy- 
 dihydro-terephthalic acid (B. 24, 2692) : 
 
 I. C0 2 .C 2 
 
 IL CO - C 
 
 The ester crystallises in bright-green triclinic prisms, or colourless 
 needles. It is insoluble in water, dissolves with difficulty in ether, 
 very readily in alcohol ; its solution shows a bright-blue fluorescence. 
 Ferric chloride imparts a cherry-red colour to it. It dissolves in 
 alkalies with a yellow colour, yielding metallic derivatives by the 
 replacement of two hydrogen atoms. It does not unite with phenyl 
 iso-cyanate, whereas the structurally similar jS-keto-hexamethylene- 
 
 carboxylic ester combines with it to form CH. 
 
 (A. 317, 104). 
 
 With hydroxylamine (in alkaline or acid solution) succino-succinic 
 ester splits off CO 2 and yields quinone-dioxime-carboxylie ester 
 C 6 H 3 (N.OH) 2 .CO 2 R, melting at 174 (B. 22, 1283). 
 
 With phenyl-hydrazin it forms a phenyl-hydrazin derivative of 
 dihydro-terephthalic acid (B. 24, 2687 ; 26, R. 590), while with hydrazin 
 it yields hexahydro-benzo-3, ^-dipyrazolone (q.v.) (B. 27, 472) ; with 
 Am acetate, di-imino-succino-succinic ester, m.p. 178, which is oxidised 
 by Br to p-diamido-terephthalic ester (C. 1905, II. 1240). 
 
 If sodium-succino-succinic diethyl ester be treated with alkylene 
 iodide, it yields the following compounds : 
 
 Diethyl-succino-suecinic ester : m-body is liquid ; trans-body melts 
 
 at 65. 
 Di-n-propyl-suecino-succinie ester : cis-body is liquid ; trans-body 
 
 melts at 86. 
 Di-iso-propyl-sueeino-suceinie ester : cis-body is liquid ; trans- 
 
 body melts at 116. 
 Methyl-n- and methyl-iso-propyl-suceino-suceinic ester boil at 195- 
 
 200 (25 mm.). 
 
 p-Dichloro-hydroquinone-dicarboxylie ester C 6 C1 2 O 2 (CO 2 C 2 H 5 ) 2 , 
 melting at 195, consists of yellowish-green crystals (B. 21, 1761). 
 When reduced with zinc dust and glacial acetic acid, it becomes p-di- 
 ehloro-hydroquinone-dicarboxylie ester C 6 C1 2 H 2 O 2 (C0 2 C 2 H 5 ) 2 , crystal- 
 lising in two different forms colourless needles and yellow-green 
 plates (B. 20, 2796 ; 21, 1759 ; 23, 260). Similar behaviour is shown 
 by dibromo- and di-iodo-hydroquinone-dicarboxylic esters (B. 32, 1742). 
 Compare the two forms of 2, 5-dioxy-terephthalic ester. 
 
 p-Dioxy-quinone-dlcarboxylic ester C 6 2 (OH) 2 (CO 2 C 2 H 5 ) 2 , melting 
 
HYDRO-BENZOL-TRICARBOXYLIC ACIDS 483 
 
 at 151, may be prepared by shaking dichloro-hydroquinone-dicarboxylic 
 ester with sodium hydroxide, and by the action of nitrous acid upon 
 dioxy-terephthalic ester (B. 19, 2385). It crystallises in pale-yellow 
 flakes and intense greenish-yellow prisms (B. 20, 1307). It reacts acid, 
 and forms salts with two equivalents of the metals. It does not form 
 a dioxime with hydroxylamine, but an oxy-ammonium salt, and with 
 phenyl-hydrazin a phenyl-hydrazin salt (B. 22, 1290). Further- 
 more, it does not react with phenyl iso-cyanate (B. 23, 265). Boiling 
 hydrochloric acid decomposes the ester into carbon dioxide and dioxy- 
 quinone. By the absorption of two atoms of hydrogen (by reduction 
 with sulphurous acid) the ester becomes : 
 
 Tetroxy-terephthalie ester C 6 (OH) 4 (CO 2 R 2 ), or dioxy-quinone-di- 
 hydro-carboxylie ester C 6 H 2 (O 2 )(OH) 2 (CO 2 R) 2 . It crystallises in 
 golden-yellow flakes, and melts at 178 (B. 20, 2798). Its alkaline 
 solution oxidises on exposure to the air (giving up two hydrogen atoms) 
 to dioxy-quinone-dicarboxylic ester ; hence it yields the same products 
 with hydroxylamine and phenyl-hydrazin (B. 22, 1291). It forms a 
 tetracarbanilido-derivative (B. 23, 267) with four molecules of phenyl 
 iso-cyanate. 
 
 Phloro - gluein - diearboxylie ester ^Z 5 CO ' m ' p ' 
 
 104, is formed by the condensation of three molecules sodium-malonic 
 acid ester on heating to I2O-I45, with rejection of carbonic acid ester, 
 with acetone-tricarboxylic ester as an intermediate product ; also by 
 the condensation of acetone-dicarboxylic ester and malonic ester with 
 sodium ethylate (B. 29, R. 1117 ; 41, 4171). It behaves like succino- 
 succinic ester, dissolves without change in alkalies, and is coloured a 
 cherry-red by ferric chloride. With acetic anhydride it forms a tri- 
 acetyl derivative with hydroxylamine or trioxime (B. 21, 176), with 
 phenyl iso-cyanate or tricarbanilido-derivative (B. 37, 4637). Fused 
 with caustic potash, it forms phloro-glucin. 
 
 3. HYDRO-BENZOL-TRICARBOXYLIC ACIDS. 
 
 Among these we have the dioxy-phenyl-aeetic-dicarboxylie esters 
 C0 2 RCH/<; C(C0 2 R)V C H 2 C0 2 R, condensation products of acetone- 
 
 \Lx(J. \^t 2 - / 
 
 diearboxylie ester (C. 1900, II. 963), and the analogous 
 
 Dihydro-oxy-phenyl-aeetic-diearboxylie ester 
 
 .H.. m.p. 82, obtained by 
 
 condensing glutaconic ester by means of sodium ethylate free from 
 alcohol (B. 37, 2113). 
 
 Dlhydro-methyl-trimesime acid CH/WHHCH fa 
 
 formed from pyro-racemic acid by heating with sodium hydroxide. 
 The acid is the intermediate product of the synthesis of uvitinic acid 
 with pyro-racemic acid. On heating with concentrated sulphuric acid 
 it splits off CO 2 and 2H, and passes completely into uvitinic acid ; on 
 fusing it yields uvitinic acid besides dihydro-uvitinie acid C 6 H 5 (CH 3 ) 
 (COOH) 2 , m.p. 236, and several tetrahydro-uvitinic acids. On reduc- 
 tion with Na amalgam we obtain tetrahydro-methyl-trimesinic acid 
 C 6 H 6 (CH 3 )(COOH) 3 , m.p. 221 -with decomposition (A. 305 125). 
 
484 ORGANIC CHEMISTRY 
 
 4. HYDRO-BENZOL-TETRACARBOXYLIC ACIDS. 
 
 Acids having two carboxyl groups attached to the same carbon 
 atom have been obtained synthetically in the action of trimethylene 
 bromide upon the disodium compound of methylene-dimalonic ester, 
 as well as from the interaction of methylene iodide and disodium- 
 trimethylene-dimalonic ester : hexamethylene-i, i, 3, 3-tetracarboxylic 
 ester, and from n-butane-tetracarboxylic ester with ethylene bromide : 
 hexamethylene-i, i, 4, 4-tetracarboxylic ester (Perkin, jun.) : 
 (C0 2 C 2 H 5 ) 2 (C0 2 C 2 H 5 ) 2 
 
 (C0 2 .C 2 H 5 ) 2 (C0 2 .C 2 H 5 ) 2 . 
 
 1, 1, 3, 3-Hexamethylene-tetraearboxylic acid decomposes at 220 
 with the elimination of 2CO 2 into hexahydro-iso-phthalic acid (B. 25, 
 R. 159, 274). 
 
 Terpenes. 
 
 The volatile or ethereal oils, obtained mostly by the distillation of 
 various plants (chiefly Coniferae and Citrus species) with steam, more 
 rarely by pressing them, or by extraction with volatile solvents or 
 fats, contain, along with different compounds, certain hydrocarbons 
 having the formula C 10 H 16 , which are called terpenes. 
 
 Terpenes C 10 H 16 , being the important, and often the chief, compo- 
 nents of many ethereal oils of great value in perfumery, demand 
 particular attention. They are more or less closely related to p-cymol 
 or p-iso-propyl-methyl benzol, and a few to m-cymol. 
 
 Their classification, and the possibility of distinguishing the indi- 
 vidual true terpenes, are mainly due to the painstaking researches of 
 O. Wallach,* who has brought order and system out of this chaotic 
 mass of hydrocarbons of the most varying origin. 
 
 The terpenes can be divided into two groups according to their 
 behaviour. The first group contains the doubly unsaturated mono- 
 cyclic terpenes, which can add four quadrivalent atoms, or atomic 
 groups, and which can be regarded as true dihydro-p-cymols. To 
 these belong limonene, dipentene, terpinolene, terpinene, and phellan- 
 drene. To these must be added sylvestrene and carvestrene, which 
 also contain two double bindings, but are derived from m-cymol. 
 
 Terpenes of the second group are chiefly distinguished from these 
 dihydro-cymols by adding only two univalent atoms or atomic groups, 
 which indicates that they must contain a double carbon ring. The 
 most important representatives of these bicyclic terpenes are camphene, 
 pinene, fenchene, and sabinene. Some members of both groups are 
 related to each other by transitional reactions. Completely saturated 
 tricyclic terpenes have not been found up to the present among the 
 ethereal oils. Quite recently terpenes of the formula C 10 H 16 have 
 become known, which contain no closed carbon chain, and are 
 therefore distinguished from the real cyclic terpenes by calling them 
 acyclic or olefinic terpenes (B. 24, 682). 
 
 Beside the terpenes proper, we often find, among ethereal oils, hydro- 
 
 " O. Wallach, Terpene und Campher, Leipzig, 1909. 
 
TERPENES 485 
 
 carbons of higher boiling-points, having the same percentage composi- 
 tion but a higher molecular weight. Among these we have the so- 
 called sesqui-terpenes C 15 H 24 , the di-terpenes C 20 H 32 , and poly-terpenes 
 (C 5 Hj.) x . The same percentage composition is also shown by isoprene 
 C 5 H 8 , generated by distillation of rubber and closely related to the 
 terperies, easily polymerised, e.g. into dipentene. Isoprene has there- 
 fore also been called hemi-terpene. 
 
 From the terpenes a large number of alcohols and ketones of the 
 general composition C 10 H 16 O, C 10 H 18 O, and C 10 H 20 O are derived. These 
 are usually found besides the terpenes in the ethereal oils, and are com- 
 prised under the name " camphors," since the commercially important 
 common, or Japanese, camphor is among them. Corresponding to the 
 olefinic terpenes we have the olennic camphors, and corresponding to 
 sesqui-terpenes we have the sesqui-terpane camphors. We must 
 therefore discuss the terpene alcohols and terpene ketones with their 
 transformation products in connection with the terpenes and their 
 addition products. 
 
 In the isolation of the terpenes the same difficulties are encountered 
 as are met with in the preparation of dihydro-benzols. We nearly 
 always obtain a mixture of closely related link-isomeric hydrocarbons, 
 and it seems doubtful whether a perfectly uniform terpene has, as yet, 
 been prepared. The elucidation of the constitution of the terpenes 
 has, therefore, been a matter of special difficulty, but since the works 
 of Baeyer, Perkin jun., Sellner, Wagner, and especially Wallach, have 
 appeared, the structure of the majority of terpenes, and their relations 
 to each other, appear to be settled. In many cases, as in dipentene, 
 terpinene, sylvestrene, and carvestrene, a complete synthesis has been 
 carried out, while in other cases, as in pinene, phellandrene, camphene, 
 and fenchene, at least a partial synthesis has been effected. The isola- 
 tion and the purification of the camphors are much easier. Many of 
 them are distinguished by their ready crystallisation, while others may 
 be easily regenerated in a pure state from characteristic derivatives. 
 Here also the elucidation of the constitution has been followed by 
 numerous total syntheses, e.g. camphor, menthone, a-terpineol, etc. 
 The synthesis has here taken a step further, as also in some of the 
 terpenes, by preparing new compounds, not yet found among ethereal 
 oils, but closely related in their constitution and behaviour to the 
 natural products, and thus creating new types of terpenes and 
 camphors. 
 
 The question of the constitution of the sesqui-terpenes and poly- 
 terpenes, as well as the oxygen-containing derivatives, is almost com- 
 pletely unsolved up to the present. 
 
 Properties. The true terpenes, when pure, are colourless, strongly 
 refracting liquids. Camphene alone is a solid. They boil, without 
 decomposition, at i55-i8o. They are very volatile with steam, and 
 have a pleasant odour. Many are optically active. Some, indeed, 
 exist in two optically active forms with equal but opposite rotatory 
 power. Dipentene is a racemic terpene. 
 
 Behaviour. (i) Terpenes polymerise very readily. (2) Acids trans- 
 pose many terpenes very easily into linkage-isomeric terpenes. (3) 
 Many are oxidised by the oxygen of the air (compare a-pinene and 
 j3-phellandrene). They then manifest a tendency to resinify (see B. 29, 
 
486 ORGANIC CHEMISTRY 
 
 R. 658). The formation of benzene derivatives by oxidising terpenes 
 is very important. Thus, turpentine oil with iodine yields p-cymol ; 
 with nitric acid, p-toluic acid and terephthalic acid. (4) The signifi- 
 cance of the addition reactions for the classification of the terpenes has 
 already been pointed out above : (a) By addition of hydrogen the ter- 
 penes form hydro-terpenes (B. 36, 1033). (b) The addition of chlorine 
 and bromine, as well as of hydrogen haloids, in glacial acetic acid at 
 low temperatures, gives rise to haloid hydro-terpenes. Some of these 
 are well-crystallised compounds, which can be used for differentiating 
 the terpenes. (c) Nitrosyl chloride NOC1 (Tilden), or an alkyl nitrite, 
 glacial acetic acid, and hydrochloric acid acting upon terpenes give 
 rise to well-defined terpene nitroso-chlorides. With primary and 
 secondary bases, these, usually unstable, nitroso-chlorides form stable 
 terpene-nitrol-amines, or, with rejection of HC1, nitroso-terpenes, 
 which are useful for characterisation. The latter make a transition 
 from the terpenes to the terpene ketones (see Limonene nitroso-chloride) . 
 (d) Several terpenes unite with N 2 O 4 , forming nitrosates C 10 H 16 (NO). 
 O.NO 2> and with N 2 O 3 , yielding nitrosites C 10 H 16 (NO).O.NO, or pseudo- 
 nitrosites (nitrites) C 10 H 1 (NO).NO 2 (A. 332, 313). The nitroso- 
 chlorides, nitrosates, and nitrosites are bimolecular in the solid state, 
 and should, therefore, be regarded as bis-nitroso-chlorides, bis-nitro- 
 sates and bis-nitrosites. In their transformations they behave as 
 monomolecular compounds (B. 28, 648 ; 29, 10). (e) By the action 
 of ozone the terpenes are converted into ozonides, while, with dilute 
 KMnO 4 solution, they become glycols by attaching 2HO. Both 
 reactions are important for determining the constitution of the terpenes. 
 
 Concerning the addition of trichloro-acetic acid and formaldehyde 
 to terpenes, see B. 29, 695 ; 32, 57. 
 
 Nomenclature. In most cases camphor and the terpenes are 
 designated by names derived from the plants in which they were 
 first observed, and which contain them most abundantly in their 
 ethereal oils. Since many terpenes, formerly considered uniform, 
 have lately been found to be mixtures, the terpenes isolated from 
 them have been distinguished from each other by prefixing Greek 
 letters, e.g. a-, jS-, and y-terpinene. 
 
 Baeyer, observing the " Geneva nomenclature," suggested that the 
 cyclic terpenes containing the same carbon skeleton as p-cymol, the 
 dihydro-p-cymols, be called terpadienes ; then the tetrahydro-cymols 
 would be terpenes, and hexahydro-cymol terpane. To obtain names 
 for the terpenes which would be designated, according to this sugges- 
 tion, as terpadienes, Wagner calls hexahydro-cymol menthane, the 
 tetrahydro-cymols menthenes, and the dihydro-cymols or terpenes 
 menthadienes (B. 27, 1636, footnote). 
 
 The latter terminology has become most usual. In order to 
 indicate the constitution of the dihydro-cymoles, the carbon atoms 
 are designated by numbers : 
 
 65 io 
 
 The dihydro - cymol of the formula CH 3 .C^ ; H 2\c=C(CH 3 ) 2 
 
 \CHjj- 
 
OLEFINIC TERPENE OR TERPENOGEN GROUP 487 
 
 would be called A 1 ' 4 '( 8) -menthadiene, the dihydro - cymol 
 CH 3 .C^ CI **\C.CH(CH 3 ) 2 , A^-menthadiene. The terpenes wiU 
 
 N CH-2 CtL'y 
 
 be discussed in the following groups : 
 
 A. Olefinic terpene or terpenogen group. 
 
 B. Monocyclic terpene or menthane group. 
 
 C. Bicyclic terpene groups. 
 
 I. Sabinane or tanacetane group. 
 II. Carane group. 
 
 III. Pinane group. 
 
 IV. Camphane group. 
 
 D. Sesqui-terpene and poly-terpene groups. 
 
 To the hydrocarbons of each group must be added the alcohols and 
 ketones, the so-called camphors. 
 
 A. OLEFINIC TERPENE OR TERPENOGEN GROUP. 
 
 Many olefin hydrocarbons, alcohols, aldehydes, and acids with 
 open carbon chain are included under this designation. They occur 
 in ethereal oils, or in the transposition products obtained from the 
 latter. They are distinguished chiefly by the fact that they, as 
 a rule, are easily converted into hydro-aromatic, terpene-like, or 
 aromatic substances. 
 
 i. Olefinic Terpenes. Myrcene, b.p. 67 (20 mm.), sp. gr. 0-8025 
 (15), W D =1-4673, occurs with 1-phellandrene and the aromatic phenols 
 of the cinnamic series in bay oil. Its formula is C 10 H 16 =(CH 3 ) 2 
 C : CH.CH 2 .CH 2 C( : CH 2 ).CH : CH 2 or CH 2 : C(CH 3 ).CH 2 .CH 2 .CH 2 .C 
 ( : CH 2 ).CH : CH 2 , b.p. 20 67, D 15 0-8025. It is also found in the 
 ethereal oil of Lippia citriodora. The terpene isolated from hop oil is 
 also probably identical with myrcene (C. 1903, I. 1028). 
 
 Artificially, it is prepared by eliminating water from linalool (see 
 below) by heating with KHSO 4 . It adds 4 Br atoms. By reduction 
 with sodium and alcohol we obtain dihydro-myreene C 10 H 18 , b.p. 172, 
 tetrabromide, m.p. 88, which is converted by glacial acetic-sulphuric 
 acid into the isomeric cyclo-dihydro-myrcene (B. 34, 3126). By 
 heating under pressure to 300, myrcene is polymerised to dimyrcene, 
 b.p. 13 i6o-2OO, and to undistillable poly-myrcenes ; with N 2 O 3 
 dimyrcene gives a nitrosite (Ci H 15 N 3 O 7 ) 2 , apparently identical with the 
 nitrosite of the same composition obtained from rubber (B. 35, 3264). 
 
 Ocimene C 10 H 16 =(CH 3 ) 2 C : CH.CH 2 .CH : C(CH 3 )CH : CH 2 (?), 
 b.p. 30 81, Dj 5 0-8031, has been obtained from the ethereal oil of 
 Ocimum basilicum. It differs from myrcene only by the position of a 
 double link, since sodium and alcohol reduce it to dihydro-myreene 
 with addition of two H atoms. On oxidation with ozone, we obtain, 
 among other products, acetone, methyl-glyoxal, and malonic dialdehyde 
 (C. 1907, II. 679 ; 1909, I. 373). 
 
 Anhydro-geraniol C 10 H 16 , b.p. ij2-iy6, sp. gr. 0-8232 (20), 
 n D = 1-4835, is obtained by heating geraniol with potassium bisulphate 
 to 170. It can also take up six bromine atoms (B. 24, 682). Linalao- 
 lene C 10 H 18 boils at i65-i68. Its specific gravity is 0-7882 (20), 
 n D = 1-455. It is formed in the reduction of linalool (B. 27, 2520). 
 
 Isoprene C 5 H 8 , b.p. 37, must be considered under the olefinic 
 
4 88 ORGANIC CHEMISTRY 
 
 terpenes or terpenogens. It is a distillation product from rubber. 
 It may be obtained by conducting vapours of turpentine oil through 
 tubes at a dull-red heat (A. 228). On its synthesis by disintegration of 
 jS-methyl-pyrrolidin, see this. 
 
 Isoprene very probably consists in the main of methyl-divinyl, 
 
 ; H 3^C C=CH 2 . It can take up two molecules of hydrogen 
 CH 2 ^ 
 
 bromide, forming dimethyl - trimethylene bromide. It polymerises 
 very readily to dipentene (/. pr. Ch. 2, 55, i ; C. 1900, II. 331) : 
 
 Under different conditions isoprene is polymerised to para-rubber. 
 
 2. Olefinic Terpene Alcohols. d-Citronellol C 10 H 2a O=CH 2 : C(CH 3 ) 
 CH 2 .CH 2 .CH 2 CH(CH 3 )CH 2 .CH 2 OH (?), b.p. 15 ii3-ii4, was first 
 obtained by the reduction of d-citronellal ; it is found native in Java 
 citronel. It is a colourless oil, smelling agreeably of roses. Its con- 
 stitution follows from its connection with d-citronellol. An alcohol 
 very similar to d-citronellol, but kevo-rotatory, l-citronellol, 1-rhodinol, 
 is found, besides geraniol, in several species of rose, geranium, and 
 pelargonium oils. It is probably link-isomeric with d-citronellol in the 
 sense of the formula (CH 3 ) 2 C : CH.CH 2 .CH 2 CH(CH 3 )CH 2 CH 2 OH, 
 since, on oxidation, it passes into an aldehyde isomeric with d-citron- 
 ellal, viz. rhodinal. But the question of the constitution of the 
 citronellols cannot be regarded as finally decided. An i-citronellol, 
 i-rhodinol, b.p. 10 110, is formed by the reduction of the synthetic 
 geranic acid (B. 29, 923 ; 30, 33 ; C. 1904, II. 440 ; vgl. B. 29, R. 785). 
 
 Geraniol C 10 H 18 O=(CH 3 ) 2 C CH.CH 2 .CH 2 .C(CH 3 ) : CH.CH 2 OH, 
 b.p. 17 I2O-I22, forms the chief alcoholic constituent of geranium oil, 
 rose oil, pelargonium oil, palma rose oil, etc., and is the most frequently 
 occurring aliphatic terpene alcohol (B. 29, R. 785) ; it yields a character- 
 istic crystallised compound with calcium chloride, which can be em- 
 ployed for separating geraniol from ethereal oils. It is optically 
 inactive, and has the same relation to citral as citronellol has to citron- 
 ellal. The synthesis of geraniol is accomplished with that of citral. 
 An alcohol probably stereo-isomeric with geraniol 
 
 Nerol, b.p. 225, D 15 0-880, has been found in the oils of neroli, 
 petit grain, bergamot, and linaloe, partly in a free condition, partly 
 esterified. It is distinguished from the otherwise very similar geraniol 
 by its inability to form a solid calcium chloride compound, and by the 
 formation of a crystalline tetrabromide, m.p. 119. Geraniol and 
 nerol probably stand to each other in the same relation as citral-a and 
 citral-b, geraniol corresponding to the former, and nerol to the latter 
 (B. 39, 1780.) 
 
 1-Linalool, licareol C 10 H 18 O=(CH 3 ) 2 C : CH.CH 2 .CH 2 .C(CH 3 )(OH). 
 CH : CH 2 , b.p. I97-I99, D 20 0-8702, n D = 1-4695, is found in linaloe 
 oil from Licari Kanali, as well as lavender, bergamot, limette and 
 origanum oil. 
 
 d-Linalool, coriandrol, is found in coriander oil and oil of pome- 
 granates and orange blossoms. By reduction with Ni and hydrogen, 
 geraniol and linalool, as well as ocimene, pass into 2, 6-dimethyl- 
 octane, which proves that the same carbon frame forms the basis of 
 
OLEFINIC TERPENE OR TERPENOGEN GROUP 489 
 
 all these compounds. Dilute sulphuric acid converts the linalool with 
 ease into inactive terpin hydrate ; this conversion is made with greater 
 difficulty with geraniol (B. 28, 2137). Formic and glacial acetic-sul- 
 phuric acids convert geraniol with some difficulty, and the linalools with 
 greater ease, into solid a-terpineol, m.p. 35. In this process linalool is 
 partly isomerised to geraniol, and, on the other hand, geraniol can be 
 converted into inactive linalool (/. pr. Ch. 2, 60, 244). Besides, or 
 instead of, terpin hydrate and terpineol, terpenes, like terpinene, and 
 terpinolene, are formed by stronger action of these agents. By the 
 action of geraniol esters with concentrated acids cyclo-geraniol is 
 formed, the alcohol corresponding to cyclo-citral (C. 1903, I. 266). 
 
 The constitution of these bodies, as well as that of the correspond- 
 ing aldehydes and acids, has been mainly deduced from their conver- 
 sion into methyl-heptenone (CH 3 ) 2 C : CH.CH 2 .CH 2 .CO.CH 3 , which has 
 been previously described. Again, this methyl-heptenone has been 
 employed in the synthesis of certain bodies belonging to this group. 
 Thus by condensation with zinc and allyl iodide it yields homo-linalool 
 (CH 3 ) 2 C : CH.CH 2 .CH 2 C(CH 3 )OH.CH 2 .CH : CH 2 , boiling at io2-iO4 
 (14 mm.) (B. 29, 693 ; cp. C. 1899, 1. 24). a-Alkyl-geraniols are obtained 
 from citral and alkyl-magnesium compounds (C. 1904, II. 624). 
 
 3. Olefinic Terpene-aldehydesCitionellal C 10 H 18 O=CH 2 : C(CH 3 ). 
 CH 2 .CH 2 .CH 2 .CH(CH 3 ).CH 2 .CHO (I.) and (CH 3 ) 2 C : CH.CH 2 .CH 2 .CH 
 (CH 3 ).CH 2 CHO (II.), boiling at 205, is optically dextro-rotatory. It is 
 found in citronella oil, in the oil from Eucalyptus maculata, var. 
 citriodora, etc. (B. 29, 904). 1-Citronellal has hitherto only been found 
 in Java lemon oil. Acetic anhydride condenses it to iso-pulegol, a 
 terpene alcohol very similar to, yet not identical with, pulegol, a 
 reduction product obtained from pulegon (B. 30, 22). It changes to 
 d-citronellol upon reduction. 
 
 By oxidation with KMnO 4 the acetal of citronellal in aqueous 
 solution is split up into acetone and the half-aldehyde of ^3-methyl- 
 adipinic acid, whereas in acetone solution it is converted to the extent 
 of 80 per cent, into a dioxy-aldehyde, which, on further oxidation with 
 CrO 3 , yields an oxy-dialdehyde and finally a keto-aldehyde CH 3 COCH 2 . 
 CH 2 .CH 2 CH(CH 3 ).CH 2 CHO (B. 34, 2981). Upon oxidation of the 
 citronellal with ozone, acetone and j8-methyl-adipinic acid are obtained, 
 but not quantitatively. Natural citronellal, therefore, appears to be 
 a mixture of two very similar aldehydes, which are link-isomeric in 
 the sense of the above formula (B. 41, 2187). 
 
 A laevo-rotatory aldehyde, rhodinal, closely related to citronellal, is 
 formed by oxidation of citronellal. The formula (II.) above is ascribed 
 to it. It differs from citronellal in that acetic anhydride does not 
 change it into iso-pulegol, but into a cyclic ketone, menthone. The 
 process may be represented by the following formulae : 
 
 H 2 C=C CH 3 H 2 C=C CH 3 H 3 C C CH 3 H 3 C CH CH 3 
 
 Cn a CH CH CH 
 
 CHO > H 2 C CHOH H 2 C CHO > H 2 C CO 
 
 II II II II 
 
 H 2 C CH 2 H 2 C CH 2 H 2 C CH 2 H 2 C CH 2 
 
 H 2 C 
 
 CH.CH 3 CH.( 
 
 :H.CH 3 CH.CH 3 CH.CH 3 CHCH 3 
 
 Citronellal Iso-pulegol Rhodinal Menthone. 
 
490 ORGANIC CHEMISTRY 
 
 The reverse of this process takes place on illuminating an aqueous- 
 alcoholic solution of menthone. The ring is opened, and an unsaturated 
 aldehyde similar to citronellal, but of lower b.p., 195, is formed (B. 
 40, 2421). It may be identical with the aldehyde designated as 
 mentho-citronellal, obtained by splitting up menthone-oxime (A. 296, 
 
 Citral, geranial C^^QHCH^C : CH.CH 2 .CH 2 .C(CH 3 ) : CH. 
 CHO, b.p. 228-229, is a faint-yellow oil smelling of lemon. It is 
 found in lemon oil, verbena oil, and particularly in lemon-grass oil (?), 
 from which it is prepared industrially ; also in many other ethereal 
 oils ; it is also formed by the oxidation of geraniol (C. 1908, I. 1375) J 
 synthetically, it can be prepared by the distillation of geranium acid 
 and calcium formate (B. 31, 827). The natural citral consists of two 
 structurally identical stereo-isomeric forms, citral a and b, which can 
 be separated by their different ease of condensation with cyano-acetic 
 acid to eitralidene-cyano-aeetie acids, m.p. 122 and 95 (B. 33, 877). 
 With jS-naphthylamine and pyro-racemic acid citral combines to form 
 the characteristic citryl-naphtho-cinchonic acid (q.v.), m.p. 197 (B. 
 31, 3195). Like cinnamic aldehyde, citral combines with sulphites not 
 only to form the normal bisulphite compound with attachment of 
 2SO 3 HNa to the olefin links, but also salts of eitral-dihydro-disulphonic 
 acid (B. 31, 3278). By boiling with soda solution, citral is split up into 
 methyl-heptenone and acetaldehyde (C. 1897, 1. 495). It is oxidised by 
 ozone to acetone, Isevulinic aldehyde, or laevulinic acid and glyoxal (?) 
 (B. 40, 2823). By treatment with potassium bisulphate, HI, acetic 
 acid, etc., it is converted into cymol with elimination of H 2 O. But 
 if citral derivatives, unconvertible into cymol, like citralidene-aniline 
 (C. 1901, II. 716), citralidene-acetic acid, -cyano-acetic acid, -aceto- 
 acetic ester, etc., are treated with concentrated H 2 SO 4 or H 3 PO 4 , we 
 obtain derivatives of cyclo-citral, a trimethyl-tetra.hydro-benzaldehyde. 
 Similarly, the so-called pseudo-ionone (CH 3 ) 2 C : CH.CH 2 .CH 2 .C(CH 3 ) : 
 CHCH : CHCOCH 3 , b.p. 12 I43-I45, obtained by the condensation of 
 citral with acetone, forms a hydro-aromatic ketone called ionone, under 
 the influence of concentrated H 2 SO 4 ; cp. also cyclo-dihydro-myrcene 
 (above), cyclo-geraniol, cyclo-geranic acid, and cyclo-geraniolene 
 (above). 
 
 4. Olefinic Terpene Acids. Citronellic acid (rhodinic acid, B. 29, R. 
 352) CH 2 : C(CH 3 ).CH 2 .CH 2 .CH 2 CH(CH 3 )CH 2 COOH and (CH 3 ) 2 C : 
 CH.CH 2 .CH 2 CH(CH 3 )CH 2 COOH, b.p. 10 I43-I45, obtained from 
 its nitrile formed by withdrawing water from citronell-aldoxime, 
 or by oxidation of citronellal, to which it can be restored by 
 distilling its calcium salt with calcium formate. From geranic 
 acid it is obtained by reduction with sodium and amyl alcohol (B. 
 31, 2899). 
 
 Reduction of its ester with sodium and alcohol produces i-citronellol 
 (see above), which proves the relation between the geraniol and citron- 
 ellol series. 
 
 Geranic acid (CH 3 ) 2 C : CH.CH 2 .CH 2 C(CH 3 ) : CHCOOH, b.p. 13 153, 
 is also formed from citral. It has been prepared synthetically from 
 methyl-heptenone with iodo-acetic ester and bromo-acetic ester and zinc 
 (B. 29, R. 222 ; 31, 825). Sulphuric acid converts it into isomeric 
 hydro-aromatic cyclo-geranic acid. By heating at ordinary pressures 
 
MONOCYCLIC TERPENE OR MENTHANE GROUP 491 
 
 geranic acid produces geraniolene C 9 H 16 , which is isomerised by 
 sulphuric acid into cyclo-geraniolene (A. 324, 101). 
 
 B. MONOCYCLIC TERPENE OR MENTHANE GROUP. 
 
 To this group belong the terpenes limonene, dipentene, terpinolene, 
 a-, J3-, and y-terpinene, a- and J8-phellandrene, and the synthetic A 2 4 - 
 menthadiene, which must all be regarded as dihydro-p-cymols, also 
 sylvestrene and carvestrene, which must be regarded as dihydro- 
 m-cymols. These terpenes are partly optically active, and partly 
 inactive, or racemic. Numerous transitions and transformations 
 connect the various terpenes, and several of them have been made 
 by molecular synthesis. 
 
 i. Limonene and Dipentene Group. 
 
 Limonene C 10 H 16 =CH 3 C^ CH 2 \ CHC /-CH 2 j s known in three 
 
 \CH 2 CH 2 / NCH/j 
 
 modifications d-limonene,l-limonene, and [d+1] -limonene or dipentene. 
 
 d-Limonene, citrene, hesperidene, carvene, together with pinene, is 
 among the most widely distributed terpenes. It is present in the oil 
 obtained from the shell of Citrus aurantium, in lemon oil, in the oil of 
 bergamot, in oil of dill, in oil of celery, etc. It boils at 175 ; [a] D = 
 + 106-8. 1-Limonene occurs in the oil of pine-needles, in oil of fir, 
 and in oil of peppermint. It boils at 175 ; [a] D = 105. On the 
 preparation of 1-limonene from d-carvone, see B. 33, 735. 
 
 Both limonenes are liquids, with an agreeable lemon-like odour. 
 Their specific gravity equals 0-846 (20). They differ from each other, 
 as do their derivatives, almost entirely by their opposite rotatory 
 power (A. 252, 144). The two active limonenes combine with dry 
 bromine to tetrabromides melting at 104, and having equally large but 
 opposite rotatory power of about [a] D =73. The moist haloid acids 
 change the optically active limonenes to addition products of [d+1]- 
 limonene or dipentene. 
 
 On conducting dry HC1 through a CS 2 solution of limonene, a mono- 
 chlorohydrate is obtained which, on reduction with sodium and cold 
 alcohol, gives carvo-menthene, and, on treating with dilute alkali and 
 sodium acetate, optically active a-terpineol (B. 36, 1036 ; A. 350, 154). 
 
 By gentle oxidation with KMnO 4 limonene is converted into the 
 quadrivalent alcohol C 10 H 10 (OH) 4 . When the optically active 
 limonenes are exposed to elevated temperatures they become 
 dipentenes. 
 
 The nitroso-chlorides of the limonenes deserve particular atten- 
 tion (B. 28, 1308 ; cp. also B. 29, 10). d-Limonene forms two 
 chemically identical nitroso-chlorides, with, however, different physical 
 properties : 
 
 a, d- and 1-Limonene-nitroso-chioride, m.p. 103, [a] D =3i3. 
 j3, d- and 1-Limonene-nitroso-chloride, m.p. 105, [a] D 
 
 All the four nitroso-chlorides give, on heating with sodium 
 methylate, carvoxime, m.p. 72, 1-limonene nitroso-chlorides giving 
 d-carvoxime, and d-limonene-nitroso-chlorides 1-carvoxime (cp. also 
 B. 43, 519). 
 
 [d +1] -Limonene, dipentene, cinene, sp. gr. 0-853 (B. 28, 2145 ; 
 
4Q2 ORGANIC CHEMISTRY 
 
 29, 4), boils at 175. It is associated with cineol in Oleum cince. 
 It is produced by heating d-limonene, 1-limonene, pinene, and camphene 
 to 25O-300 ; it is, therefore, present in the Russian and Swedish 
 turpentine oil, obtained by application of great heat. It is derived 
 also from the distillation of rubber, and the polymerisation of the 
 isoprene C 5 H 8 , formed simultaneously (A. 227, 295). It is also produced 
 on mixing equally large quantities of d- and 1-limonenes, as well as 
 when pinene is boiled with alcoholic sulphuric acid. It forms, too, on 
 withdrawing water from linalool, terpine hydrate, terpineol, and cineol. 
 By nuclear synthesis, dipentene is obtained from the synthetic 
 a-terpineol by heating with potassium bisulphate (C. 1904, I. 1604). 
 
 It may be prepared pure by heating its hydrochloride with aniline 
 or sodium acetate in glacial acetic acid solution. 
 
 Pure dipentene is a liquid with an agreeable odour of lemon. 
 
 Although more stable than most of the other terpenes, it can 
 yet be changed into the isomeric terpinene by alcoholic sulphuric 
 acid or hydrochloric acid. It is oxidised to p-cymol by concentrated 
 sulphuric acid or phosphorus pentasulphide. p-Cymol is also 
 obtained by treating its dihydro-bromide with bromine and reducing 
 (B. 31, 1402). 
 
 The derivatives of dipentene can be obtained not only from the 
 dipentenes, but also by mixing the corresponding derivatives of dextro- 
 and laevo-limonene. 
 
 trans-Dipentene-dihydro-chloride C 10 H 16 .2HC1 boils at 119 (10 mm.) 
 and melts at 50. eis-Dipentene-dihydro-ehloride, m.p. about 22. 
 
 The trans-dipentene-dihydro-bromide C ]0 H 16 .2HBr, from d-limonene, 
 dipentene, terpine, and cineol with hydro-bromic acid, melts at 64. 
 
 cis-Dipentene-dihydro-bromide C 10 H 16 .2HBr, melting at 37, 
 results from the action of HBr upon a well-cooled solution of cineol in 
 glacial acetic acid ; see also cis-Terpine (B. 26, 2864). 
 
 Tetrahydro-dipentene tribromide, tribromo-terpane C ]0 H 17 Br 3 , is de- 
 rived from trans-dipentene dihydro-bromide by the action of bromine 
 upon the glacial acetic acid solution (A. 264, 25). 
 
 Dipentene tetrabromide C 10 H 16 .Br 4 melts at 124 (A. 281, 140). 
 
 Dipentene dihydro-iodide C 10 H 16 .2HI melts at 77-79 (A. 239, 13). 
 
 Dipentene nitroso-ehloride C 10 H ]6 (NO)C1 melts at 102 ; see Carv- 
 oxime, p. 510 (A. 270, 175). 
 
 Terpinolene cu ^ c \^~^^> c = c <^' meltin S at 75 (14 mm.), 
 has not yet been observed in ethereal oils. It is produced when terpine 
 hydrate, terpineol, and cineol are boiled with dilute sulphuric acid, 
 and by heating pinene with the concentrated acid. Boiling oxalic 
 acid or anhydrous formic acid also liberate it from the terpineol melting 
 at 35 (A. 275, 106 ; 368, n) ; or anhydrous formic acid (A. 368, n) 
 with bromine terpinolene forms a dibromide C 10 H 16 Br 2 , m.p. 70 
 (B. 27, 447), and a tetrabromide C 10 H 16 Br 4 , m.p. 116, from which 
 it can be regenerated, in great purity, by reduction with zinc dust 
 and alcohol (B. 42, 4644). Halogen hydride is added to it with 
 formation of dipentene dihalogenides. Terpinolene belongs to the 
 most unstable terpenes, and is changed with especial ease by acids 
 displacing the semicyclic double link into the nucleus and thus 
 forming terpinene. 
 
MONOCYCLIC TERPENE OR MENTHANE GROUP 493 
 
 The Terpinene Group. The name terpinene is used for designating 
 the three following dihydro-cymols : 
 
 CH 3 .CH.CH 3 CH 3 .CH.CH 3 CH 3 .CH.CH 3 
 
 C C C 
 
 /\ /\ 
 
 H 2 C CH H 2 C CH H 2 C CH 
 
 H 2 C CH HC CH 2 HC CH 2 
 
 C C C 
 
 CH 3 CH 2 CH 3 
 
 a-Terpinene jS-Terpinene y-Terpinene. 
 
 Of these, the a- and y-terpinenes have been found in ethereal oils, 
 while the j3- terpinene has hitherto only been prepared synthetically. 
 Both the natural terpinene and the terpinene artificially prepared from 
 other terpenes or terpene alcohols represent a mixture of various 
 amounts of a- and y-terpinenes, in which a-terpinene usually pre- 
 dominates. The isolation of a perfectly pure a- or y-terpinene has 
 hitherto not been accomplished. 
 
 Terpinene (a+y), b.p. i79-i8i, D 0-846 (20) (B. 42, 2425), when 
 pure, has an odour resembling lemons and is optically inactive. It 
 has been found in cardamom oil, elemi oil, coriander oil, ajowan oil, 
 etc., of which the latter is particularly rich in y-terpinene. It results 
 on boiling dipentene, terpine, phellandrene, cineol, or dihydro-carveol 
 with dilute alcoholic sulphuric acid, and when pinene is shaken with 
 a little concentrated sulphuric acid. A partly pure y-terpinene is 
 obtained (i) from chloro-carvenene, the result of the action of PC1 5 
 upon carvenone, or by reduction of sodium and alcohol (B. 40, 2471) ; 
 
 (2) from carvenylamine by rejection of ammonia (B. 40, 1256) ; 
 
 (3) from methyl-dichloro-methyl-keto-dihydro-benzol, with iso-propyl- 
 magnesium iodide, and heating the resulting compound with alcoholic 
 potash (B. 42, 2404, 4427). The last method of formation represents 
 a complete nuclear synthesis of terpinene. 
 
 j3-Terpinene, b.p. i73-i74, specific gravity 0-838, has been 
 obtained from the condensation product of sabina-ketone with brom- 
 acetic ester and zinc by rejection of water and distillation of the 
 resulting unsaturated acid, C 9 H 14 : CHCO 2 H, m.p. 68. It unites with 
 bromine to form a crystallised tetrabromide, m.p. 155, while a- and 
 y-terpinenes only yield liquid bromine addition products (A. 362, 285). 
 
 All three terpinenes unite with two molecules of halogen hydride to 
 form well-defined terpinene dihalogenides, from which, on heating 
 with aniline or alcoholic potash, a mixture of a- and y-terpinene is 
 regenerated. On shaking up with dilute alkali, dihalogen hydrates 
 are converted into terpinene-terpin and terpinenol (q.v.), compounds 
 which are isomeric with the analogous conversion products of the 
 dipentene halogenides, terpin and terpineol. 
 
 Especially characteristic of a-terpinene is the formation of terpinene 
 nitrosite C 10 H 16 (NO).O.NO or C 10 H 15 (N.OH)O.NO, m.p. 155, 
 formed by the action of potassium nitrite upon terpinene dissolved in 
 
 flacial acetic acid, and used for discovering terpinene in ethereal oils. 
 t is insoluble in alkali, but gives, with bases, nitrolamines soluble in 
 alkali. With ammonia it thus gives terpinene-nitrolamine C 10 H 16 
 
494 ORGANIC CHEMISTRY 
 
 (N.OH).NH 2 , m.p. 118 (A. 241, 320). With zinc dust the terpinene 
 nitrosite and the nitrolamines are reduced to carvenone, while sodium 
 and alcohol reduce them to tetrahydro-carvone and tetrahydro-carvyl- 
 amine (B. 40, 579). 
 
 On oxidation with potassium permanganate, a-terpinene yields 
 a, ai-dioxy-a-methyl-aj-iso-propyl-adipinic acid, m.p. 189, which 
 can be further broken down to co-dimethyl- acetonyl-acetone (A. 362, 
 293): 
 
 CH 2 C(CH 3 )=CH _ CH 2 C(CH 3 )OH C0 2 H CH 2 CO.CH 3 
 
 CH 2 C(C3H 7 ) =CH "*" CH 2 C(C3H 7 )OH C0 2 H CH 2 CO.CH(CH 3 ) a 
 
 The isomeric y-terpinene, similarly oxidised, yields an erythrite 
 C 10 H 16 (OH) 4 , m.p. 237, which, under the action of dilute sulphuric 
 acid, gives a mixture of thymol and carvacrol (C. 1909, II. 2159). 
 
 Terpinene Dihydro-halogenides. These, like the corresponding 
 dipentene compounds, occur in two stereo-isomeric forms, of which 
 only the trans-form is solid at ordinary temperatures. They are 
 formed from the terpinenes, but with greater ease, by the action of 
 halogen hydride upon the bicyclic sabinene and thujene. Also 
 from terpinene-terpin, and the terpineols, with glacial acetic halogen 
 hydride. trans-Terpinene diehloro-hydrate, dibromo-hydrate, and 
 di-iodo-hydrate melt at 52, 59, and 76. A terpinene monochloro- 
 hydrate C 10 H 16 HC1, bp. 12 87-92, results from terpinene and sabinene 
 with dry HC1 in carbon bisulphide solution. It corresponds to ter- 
 pineol-4, since sodium and alcohol reduce it to carvo-methene (B. 40, 
 
 Phellandrene Group. By a- and j8-phellandrene we denote two 
 isomeric dihydro-cymols, both marked by the ease with which they 
 combine with nitrous acid to form well-marked pseudo-nitrosites. 
 The phellandrenes belong to the most unstable terpenes, converted 
 by acids into other terpenes, like dipentene and terpinene. With 
 halogen hydride and bromine they only form liquid addition pro- 
 ducts, and, since they cannot be regenerated from the crystallised 
 nitrites, they have not been hitherto obtained pure. 
 
 j3-Phellandrene c 10 H 16 =CH 3 .c^-^^CH.CH<(^3 > bp . i 73 _i 75 . 
 
 is optically active and is pretty frequently found in ethereal oils, both 
 with right-hand and left-hand rotation. d-a-Phellandrene has been 
 found in water of fennel oil, elemi oil (A. 246, 233), ginger-grass oil, 
 while 1-a-phellandrene has been found in Australian eucalyptus oil of 
 Eucalyptus amygdalina and in aniseed oil (?). 1-a-Phellandrene has 
 been synthesised from the product of A 2 -iso-propyl-cyclo-hexenone 
 and CH 3 MgI by rejection of water (A. 359, 285), and also from chloro- 
 phellandrene, the product of the action of PC1 5 upon carvotane-acetone, 
 by reduction with sodium and alcohol (B. 38, 1832). 
 
 On oxidation with potassium permanganate, a-phellandrene 
 produces a-oxy-/Mso-propyl-glutaric acid and iso-propyl-succinic acid. 
 Sodium and alcohol reduce it to carvo-menthene (B. 36, 1749). 
 
 The bimolecular a-phellandrene nitrite, obtained with nitrous acid, 
 occurs in two stereo-isomeric (?) forms, m.p. 105 and 113, and on 
 reducing with zinc and glacial acetic acid it yields a-phellandrene- 
 diamine C 10 H 16 (NH 2 ) 2 , b.p. 133 (17 mm.), which shows that both 
 
MONOCYCLIC TEREENE OR MENTHANE GROUP 495 
 
 nitrogen atoms are linked with carbon. With bases, it does not yield 
 nitrolamines like the formal nitrosites. With sodium alcoholate it 
 splits off hypo-nitrous acid and forms nitro-a-phellandrene, b.p. 
 I25-I29 (9 mm.), which can be reduced, with zinc and glacial acetic 
 acid, to active carvotane-acetone, and, with sodium and alcohol, to 
 tetrahydro-carvone (A. 336, 9). 
 
 C.CH 3 C.CH 3 C.CH 3 CH.CH 3 
 
 //\ ./\ /\ x\ 
 
 HC CHNO 2 HC CNO 2 HC CO H 2 C CO 
 
 H 2 C CHNO " ^ H 2 C CH "* H 2 C CH 2 "* H 2 C CH 2 
 
 v \y \/ \/ 
 
 CH.CgH 7 CH.CgH, CH.CaH 7 CH.QH, 
 
 a-Phellandrene Nitro-a-phellan- Carvotane-acetone Tetrahydro- 
 
 nitrite drene carvone. 
 
 >p>u occurs 
 
 in a dextro-rotatory form in the oil of Phellandrium aquaticum. In 
 the air it oxidises very readily, splits off the hemi-cyclic CH 2 group, 
 and passes into A 2 -iso-propyl-cyclo-hexenone (A. 343, 29). By 
 oxidation with a very dilute permanganate solution, we obtain a 
 glycol C 10 H 16 (OH) 2 , b.p. 150 (10 mm.), which, on treatment with 
 dilute sulphuric acid, yields tetrahydro-cumin-aldehyde besides 
 dihydro-cumin-alcohol. Stronger action by potassium permanganate 
 produces a-oxy-/?-iso-propyl-adipinic acid : 
 
 CH 2 CH 2 CO 2 H CH 2 CH 2 C : CH 2 CH 2 CH 2 CO 
 
 QH 7 .CH CH(OH).CO 2 HTc3ll 7 CH CH=CH "^CgH 7 .CH CH CH 
 
 a-Oxy-/Mso-propyl- /9-Phellandrene A 2 -Iso-propyl-cyclo- 
 
 adipinic acid | hexenone 
 
 CH 2 CH 2 C(OH)CH 2 OH CH 2 CH 2 CH.CHO 
 
 CgH 7 CH-^cH CH " > c 3 H 7 .CH CH=CH 
 
 jS-Phellandrene-glycol Tetrahydro-cumin-aldeliyde. 
 
 The j3-phellandrene nitrite C 9 H 14 (NC).CH 2 .NO 2 , m.p. 98 and 102, 
 produced by nitrous acid, is reduced by zinc and glacial acetic acid to 
 jS-phellandrene-diamine, b.p. 134 (n mm.), while sodium and alcohol 
 reduce it to cumin-aldehyde. Sodium alcoholate converts it into 
 nitro-jS-phellandrene C 10 H 15 NO 2 , which, on reduction with zinc and 
 acetic acid, passes into dihydro-cumin-aldehyde (A. 340, i). 
 
 A 2 > 4 -Menthadiene CH 3 .CH<^=^CH.CH(CH 3 ) 2 , b.p. 174, usually 
 
 obtained synthetically by V. Baeyer from succinylo-succinic ester by 
 conversion into i-methyl-4-iso-propyl-cyclo-hexandione-2,5, reduction, 
 and rejection of 2H 2 O. It yields no crystalline bromide or nitrosite, 
 and does not seem to be identical with any of the known terpenes 
 (B. 26, 232 ; 27, 453). 
 
 A 3 8 ( 9 )-p-Menthadiene C 10 H 16 , b.p. 184, tetrahydro-p-toluylic acid 
 ester with MgICH 3 (C. 1910, II. 80 ; see B. 39, 2585). 
 
 Sylvestrene C 10 H 16 = CH 3-C=CH CH.C(CH 3 ) : CH 2> bp ^^ has 
 
 been found in the Indian, Swedish, and Russian turpentine oil, and oil 
 of pine-needles. It is dextro-rotatory, [a] D = +66-32 (A. 252, 149), 
 and possesses a pleasant odour resembling lemons. Synthetically, it 
 has been prepared from d-A 2 -tetrahydro-m-toluic ester by trans- 
 
496 ORGANIC CHEMISTRY 
 
 position with CH 3 MgI and elimination of water (Perkin) . Its solution 
 in acetic anhydride is coloured a deep blue by the addition of con- 
 centrated sulphuric acid. Similar behaviour is shown by carvestrene 
 and dihydro-benzol, while other terpenes, under the same conditions, 
 show a red or reddish-yellow colour. It is one of the most stable of 
 terpenes, and cannot be transformed into isomeric terpenes by means 
 of either heat or acids (A. 239, 28). On bromination of its dihydro- 
 bromide and subsequent reduction with zinc dust and HC1, m-cymol is 
 obtained, while limonene, treated similarly, gives p-cymol. Sylves- 
 trene is probably, therefore, the limonene of the m-cymol series (B. 31, 
 2067) . Like limonene, it forms, by addition of two molecules halogen 
 hydride, dihalogenides, which, however, in contrast with the corre- 
 sponding limonene compounds, are optically active, and from which, by 
 boiling with aniline and sodium acetate, optically active sylvestrene is 
 regenerated. By treatment with dilute potash the dihydro-halogenides 
 are converted into the alcohols corresponding to terpin and terpineol, 
 viz. sylveterpineC 10 H 18 (OH) 2 , m.p. 136, and sylveterpineole C 10 H 17 OH, 
 b.p. 210 (A. 357, 72) ; dihydro-chloride C 10 H 18 C1 2 , m.p. 72 ; dihydro- 
 bromide, m.p. 72 ; dihydro-iodide, m.p. 67 ; tetrabromide C 10 H 16 Br 4 , 
 m.p. 135; nitroso-chloride C 10 H 16 (NO)C1, m.p. 107 (A. 252, 150). 
 
 Carvestrene C 10 H 16 , boiling at 178, results from the distillation of 
 carylamine chlorohydrate. It is probably the optically inactive 
 isomeride corresponding to sylvestrene (B. 27, 3485). Since, like the 
 latter, it passes into m-cymol, it is probably the dipentene of the m-cymol 
 series (B. 31, 1405). Blue coloration, see Sylvestrene. By nuclear 
 synthesis it has been obtained from the racemic A 2 -tetrahydro-m- 
 toluic ester (C. 1907, I. 1408). 
 
 The dihydro-chloride melts at 52, and the dihydro-bromide at 48-5o. 
 On the synthesis of a terpene linkage isomeric with carvestrene, viz. 
 A 6 8 ( 9 )-m-menthadiene, b.p. 177, see C. 1909, I. 171. 
 
 Hydro-terpenes. Hydrocarbons derived from menthol and 
 tetrahydro-carveol as foundation substances, and containing two to 
 four atoms more of hydrogen than the preceding bodies, bear close 
 kinship to the latter. The two alcohols just mentioned are derived in 
 such a manner from hexahydro-p-cymol that in both of them there 
 are present secondary ring-alcohols of this hydrocarbon. When they 
 lose water, menthene and carvo-menthene are produced. The produc- 
 tion of the latter compounds from limonene and terpinene monochloro- 
 hydrate, as well as from a-phellandrene, by reduction with sodium and 
 alcohol, has been mentioned above. 
 
 Carvo-menthene C 10 H 18 , b.p. 175 (cp. /. pr. Ch. 2, 66, 274 ; B. 40, 
 2959). Its nitroso-chloride melts at 87, and its nitrol-benzyl-amine at 
 1007. 
 
 Menthene, mentho-menthene C 10 H 18 , b.p. 167, with specific gravity 
 0-806 or 0-814 (20). It is best made by acting with potassium 
 phenolate upon menthyl chloride (B. 29, 1843) ; or by the dry distilla- 
 tion of menthyl- xanthogenic methyl ester Ci H 10 OCSSCH 3 (B. 32, 3332) ; 
 it is obtained direct from menthol by heating with dilute sulphuric acid 
 or oxalic acid (C. 1900, I. noi ; 1901, II. 1158; B. 37, 1374). i-Men- 
 thene has been obtained from the condensation product of I, 4-methyl- 
 cyclo-hexanone with iso-propyl-magnesium iodide by splitting off water 
 (C. 1906, I. 341). Nitroso-chlorides, see B. 29, 4. 
 
MONOCYCLIC TERPENE OR MENTHANE GROUP 497 
 
 The constitution of the two hydrocarbons follows from their re- 
 lation to carvacrol and menthol. Carvacrol readily results from a 
 rearrangement of carvone, which, upon reduction, yields tetrahydro- 
 carveol, with which menthol is isomeric. The constitution of menthol, 
 on the other hand, is proved by conversion of the corresponding ketone, 
 menthone, into 3-chloro-cymol and thymol. By removing water from 
 these alcohols, or hydrogen chloride from their chlorides, two different 
 tetrahydro-cymols are formed : 
 
 2 ^ rH 3 2 
 
 [ [ 
 
 CH 2 -CH 2 CH 3 
 
 Menthol Menthene 
 
 /CH(OH) CH 2 \ rH /CH 3 rH r ^CH CH 2 \ rH 
 
 [ \CH 2 -- CH 2 / ( [ \CH 3 ~ ' H3 - C \CH 2 -CH 2 / ( [ \CH 
 
 Tetrahydro-carveol Carvo-menthene. 
 
 When oxidised with potassium permanganate, menthene yields (i) 
 menthene glycol, (2) a keto-alcohol boiling at 105 (13-5 mm.), and 
 (3) the fatty acids arising from menthone (B. 27, 1636) ; while carvo- 
 menthene yields (i) a ketone aldehyde C 10 H 18 O 2 , b.p. about 120, (2) a 
 ketonic acid C 10 H 18 O 3 , b.p. 9 about 175, and (3) j3-iso-propyl-glutaric 
 acid (B. 40, 2959). 
 
 A A 4 ( 8 )-menthene, dihydro-terpinolene CH 3 CH/ 2 ~^2 2 ^> C : c <^2 3 > 
 
 \CH 2 Cri 2 / XClri/j 
 
 b.p. 173, D 0-831, has been obtained from the condensation product 
 of i, 4-methyl-cyclo-hexanone with bromiso-butyric ester and zinc 
 by rejection of water, and distillation of the resulting unsaturated acid. 
 Nitroso-chloride, m.p. 102. On boiling with dilute H 2 SO 4 it trans- 
 poses into i-mentho-menthene (A. 360, 70). In the same manner the 
 corresponding menthenes of the o- and m-series have been obtained 
 (A. 360, 75). 
 
 A80-Menthene CH 3 CH<^^^CH.C<^, b.p. 14 54, is formed 
 
 by reduction of iso-pulegol chloride with sodium and alcohol. On 
 oxidation, it yields hexahydro-p-acetyl-toluol and hexahydro-p- 
 toluic acid (B. 39, 2582). 
 
 By reducing menthol with HI, or menthyl chloride with sodium 
 and alcohol (B. 29, 317 ; /. pr. Ch. 2, 60, 158) a hydrocarbon has been 
 obtained which is probably hexahydro-cymol. 
 
 Hexahydro-eymol, menthane, mentho-naphthene 
 
 b.p. 169, D 0-8066. The same hydrocarbon is probably represented 
 by the hexahydro-cymol obtained by the reduction of terpin hydrate 
 (B. 23, R. 433), terpineol (C. 1905, II 135), and d-limonene (C. 1910, 1. 
 349), as well as resin oil. 
 
 2. ALCOHOLS OF THE MONOCYCLIC TERPENE OR MENTHANE GROUP. 
 
 Monacid Menthane Alcohols. Hexahydro-p-cymol yields the 
 isomeric menthols. 
 
 Secondary Menthols. 1-Menthol, mentha-camphor, 5-methyl-2- 
 
 VOL. II. 2 K 
 
4 g8 ORGANIC CHEMISTRY 
 
 iso-propyl-hexahydro-phenol CH3.CH< 2< >CH.CH(CH3) 2 (see 
 
 \UJH. 2 .L/.tl 2 - * 
 
 above), m.p. 44 and b.p. 212. It is the chief constituent of 
 peppermint oil (from Mentha piperita and Mentha arvensis, var. piper- 
 ascens). It is formed in the reduction of menthone (/. pr. Ch. 2, 55, 
 14), and is oxidised by chromic acid to 1-menthone. By the exit of 
 water it yields menthene (see above), and by reduction hexahydro- 
 cymol results (above). Potassium permanganate converts it into oxo- 
 
 menthylic acidCH 3 .CH<^^ 2 '^ 2l 5co.CH.(CH 3 ) 2 , boiling at 174 (15 mm.) 
 
 (A. 289, 362), and j3-methyl-adipic acid 
 
 melting at 89 (B. 27, 1818). 
 
 A mixture of two racemic menthols, m.p. 25 and 49, is obtained 
 by the reduction of thymol with hydrogen and nickel. From the 
 first of these, by splitting up the corresponding phthalic ester acid 
 with cinchonin or brucin, we obtain the natural 1-menthol (C. 1909, 
 I. 1872). 
 
 Menthyl chloride C 10 H 19 C1 boils at 204. The ethyl ether boils at 
 212, and the benzoyl ester melts at 54. Menthyl-xanthogenie methyl 
 ester, m.p. 39, gives menthene on dry distillation (B. 35, 2473). Iso- 
 valerianic ester, b.p. 10 126, is recommended under the name of 
 " validol " as a remedy for sea-sickness. The chloro-methyl-men- 
 thyl ether, formed by the action of HC1 upon a mixture of menthol and 
 formaldehyde, is used under the name "formane" as an antiseptic. 
 Its composition is C 10 H 19 OCH 2 C1, b.p. 16 161. 
 
 CJtl 2 - (_/Jbl2/ 
 
 isomeric with menthol, is a thick oil, volatile without decomposition. 
 It is formed when tetrahydro-carvone and carvenone are reduced in 
 moist ethereal solution with metallic sodium. A mixture of racemic 
 carvo-menthols is obtained by the reduction of carvacrol with Ni and 
 H (C. 1908, I. 733). 
 
 Its genetic connection with carvacrol (see above) would indicate its 
 constitution. 
 
 Tertiary menthols are produced when their hydro-iodic acid esters, 
 addition products of HI and menthene by means of carvo-menthene, 
 are treated with moist silver oxide (see also B. 29, 1844 ; /. pr, Ch. 2, 
 60, 259). It is noteworthy that the addition of the halogen hydrides 
 to the menthenes produces the same tertiary menthyl halogenides as 
 are obtained from menthol and tetrahydro-carveol, with the phos- 
 phorous halogenides and halogen hydrides. 
 
 Tertiary menthol-4 CH 3 .CH/ CH 2~ CH 2\c(OH).CH(CH 3 ) 2 , b.p. 100 
 
 \CH 2 CHij/ 
 
 (20 mm.), has a faint peppermint-like odour. It is formed by the 
 action of iso-propyl - magnesium iodide upon I, 4 - methyl - cyclo - 
 hexanone (C. 1906, II. 342). On heating with KHSO it yields A 4 ^- 
 menthene. 
 
 Tertiary carvo-menthol CH 3 C(OH)/CH 2 CH 2 \ CH CH(CH3 ) 2 boils at 
 
 \CH 2 CH 2 / 
 
 96-ioo (17 mm.). 
 
 Tertiary menthanol-8 CH 3 CH/^ 2 ~ :^ 2 V^H.C(OH)(CH 3 ) 2 , m.p. 36, 
 
 \CxH 2 CH 2 / 
 
MONOCYCLIC TERPENE OR MENTHANE GROUP 499 
 
 b.p. 207, from hexahydro-p-toluic ester and methyl-magnesium iodide 
 (C. 1905, II. 239). 
 
 Diacid Alcohols. In this group are the two terpins, cis-terpin 
 and trans-terpin, corresponding to the cis- and trans - dipentene - 
 dihydro-halogenides, with which they are intimately related. At 
 present the following formulas are assigned them (see B. 29, 5 ; 
 C. 1897, II. 420) : 
 
 CH 3 \ /CH 2 CH 2 \ /H H0\ XCH 2 -H 2 \ /H 
 
 HO/ \CH 2 CH 2 /^\C(CH 3 ) 2 OH CHs/ \CH 2 CH 2 / \C(CH 3 ) 2 OH 
 
 cis-Terpin trans-Terpin. 
 
 These are in harmony with the oxidation of terpin hydrate to terebic 
 acid, as well as with its formation from linalool. Cineol is to be 
 regarded as the oxide corresponding to the cis-terpin. 
 
 Terpin, cis-terpin C 10 H 18 (OH) 2 , melting at 104 and boiling at 
 258, readily attracts water and passes into a body distinguished by 
 its great power of crystallisation, viz. : 
 
 Terpin hydrate C 10 H 18 (OH) 2 +H 2 O, m.p. 117, from which it is 
 prepared by protracted heating to 100. Terpin corresponds to cis- 
 dipentene-dihydro-bromide, from which it can be obtained by treat- 
 ment with silver acetate in glacial acetic acid, and saponifying the re- 
 sulting diacetyl derivative with alcoholic potash. Terpin hydrate is also 
 produced if turpentine oil is allowed to stand with dilute nitric acid and 
 alcohol (A. 227, 284), as well as from pinene, dipentene, and d-limonene 
 with dilute acids. It forms, furthermore, on bringing dipentene and 
 d-limonene dihydro-chloride into contact with water, and when ter- 
 pineol and cineol are acted upon by dilute acids. Synthetically, it has 
 been obtained by the action of methyl-magnesium iodide upon I, 4- 
 cyclo-hexanone-carboxylic ester (C. 1907, I. 1412). 
 
 The haloid acids convert terpin hydrate into the cis- and trans- 
 dihydro-halides of dipentene. When boiled with dilute acids it passes 
 into terpineols (B. 27, 443, 815), cineol, dipentene, terpins, and ter- 
 pinolenes. 
 
 trans-Terpin C 10 H ;8 (OH) 2 , m.p. i56-i58 and b.p. 26^-26^ , is 
 formed from trans-dipentene-dihydro-bromide (see cis-Terpin), into 
 which it finally reverts upon treatment with hydrogen bromide. It does 
 not combine with water of crystallisation. 
 
 Cineol, eucalyptol C 1( )H 18 O, b.p. 176, with specific gravity 0-923 
 (16), n D =i-4559, is a liquid with a camphor-like odour, and repre- 
 sents the glycol anhydride corresponding to cis-terpin. 
 
 It occurs in many ethereal oils, in oleum cince, the worm-seed oil 
 of Artemisia cina, cajeput oil, eucalyptus oil, rosemary oil, sage oil, etc. 
 Hydrochloric acid gas conducted into a petroleum ether solution of 
 cineol precipitates an unstable addition product C 10 H 18 O.HC1 (?), 
 which water resolves into its components, and which serves for the 
 separation of cineol. With phosphoric acid, resorcin, hydrogen ferro- 
 and ferri-cyanide, etc., cineol forms compounds resembling salts 
 (B. 34, 2689 ; C. 1907, II. 240). 
 
 In glacial acetic acid solution the haloid acids change cineol i n to 
 dipentene dihydro-halides. At low temperatures hydrogen bro m ide 
 produces cis-dipentene-dihydro-bromide. P 2 S 5 converts cineol i n to 
 cymol. Potassium permanganate oxidises cineol (i) into cineoli c 
 
500 ORGANIC CHEMISTRY 
 
 (2), the anhydride (3) of which yields, upon distillation, methyl-hexylene 
 ketone or methyl-heptenone (4), while the latter may be arranged to 
 m-dihydro-isoxylene (5). This series of reactions is shown in the 
 following diagram : 
 
 CH 2 CH- CH 2 CH 2 CHCO 2 H CH a CH 2 CH 2 CH 
 
 C(CH 3 ) 2 
 
 6 
 
 C(CH 3 ) 
 
 6 
 
 C(CH 3 ) 2 C(CH 3 ) 2 
 
 6 
 
 CH 2 C(CH 3 ) CH 2 CH 2 C(CH 3 )CO 2 H CH 2 C(CH 3 )CO 2 H CH 2 COCH 3 . 
 
 Cineolic acid melts at ig6-igy with decomposition ; its anhydride 
 melts at 78 and boils at 157 (13 mm.). On heating with concentrated 
 H 2 SO 4 it yields i, 3-dimethyl-benzoic acid (B. 39, 4083). Cinenic 
 acid C 9 H 16 O 3 , m.p. 84, is formed synthetically from the hydrate of 
 methyl-heptenone by addition of prussic acid and saponification. By 
 the action of concentrated H 2 SO 4 it passes into S-acetyl-aa-dimethyl- 
 valerianic acid with migration of a methyl group (B. 33, 1129 ; 34, 
 2191 ; 41, 1278). 
 
 As terpin corresponds to the dipentene-dihalogenides, so we 
 have, corresponding to the terpinene dihalogenides, terpinene-terpin 
 CH 3 (OH)C/ 2 ;H 2 \ C(OH) .CH(CH 3 ) 2 , m .p. 138, b.p. 250, which 
 
 \Url 2 Url 2 / 
 
 sublimes on heating. It is formed by the action of dilute potash 
 upon terpinene dichlorohydrate, to which it reverts on treating with 
 glacial acetic-hydrochloric acid. It is also obtained from sabinene, 
 thujene, and terpinenols with dilute sulphuric acid (A. 356, 200). 
 On heating with oxalic acid it splits off water and passes into ter- 
 
 /CH 2 CH 2 \ 
 
 pinenol-4 and 1, 4-cineol, terpinene-cineol CH 3 Cr O- -^C.CH(CH 3 ) 2 , 
 
 \CH 2 CH 2 / 
 
 b.p. 173. This, with HBr, yields terpinene dibromo-hydrate (A. 356, 
 204). 
 
 On the meta-series compound corresponding to terpin, sylveterpin, 
 see above, and C. 1907, I. 1408. 
 
 Menthene-glyeol C 10 H 18 (OH) 2 , melting at 77 and boiling at 130 
 (13 mm.), results when menthene is oxidised with potassium perman- 
 ganate (B. 27, 1636). An isomeric 3, 8-menthene-glycol C 1 qH 18 (OH) 2 , 
 m.p. 81, b.p. 10 145, is obtained besides iso-pulegol by treating citron- 
 ellal with dilute H 2 SO 4 ; on withdrawing water it passes into iso- 
 pulegol (C. 1897, II. 304). 
 
 2, 8-Dioxy-hexahydro-cymol C 10 H 18 [2, 8](OH) 2 , a-form m.p. 113, 
 j8-form m.p. 103, is formed by reduction of oxy-dihydro-carvone, or 
 by shaking up dihydro-carveol with dilute H^SO^. On boiling with 
 25 per cent. H 2 SO 4 , it yields an oxide isomeric with cineol, dihydro- 
 pinol C 10 H 18 O, b.p. 9 58, which unites with potassium ferricyanide to 
 a crystalline compound (B. 38, 1719). 
 
 (c) Triacid menthane alcohols have been obtained by oxidising 
 menthene alcohols with potassium permanganate. 
 
 i. 2, 8, 9-Trioxy-hexahydro-cymol C 10 H 17 [2, 8, 9](OH) 3 (i), from 
 dihydro-carveol (see below), is a syrup, and with dilute sulphuric acid 
 yields an indifferent oxide C 10 H 16 O, boiling at I96-I99 (A. 277, 152) ; 
 while upon oxidation with chromic acid it forms a ketone-alcohol, 
 5-aeetyl-hexahydro-o-cresol, melting at 58 (2), which, upon further 
 
MONOCYCLIC TERPENE OR MENTHANE GROUP 501 
 
 oxidation, changes to hexahydro-m-oxy-p-toluic acid, melting at 153 
 (3). The constitution of this last acid is evident from its conversion 
 by bromine into m-oxy-p-toluie acid, melting at 203 (4). These 
 experiments give rise to the constitution formulae (B. 28, 2141) : 
 
 CH 3 CH 2 
 
 CH 3 CH 2 
 
 CH 3 CH 2 
 
 CH 3 CH 2 OH 
 
 CH 3 
 
 v 
 
 C 
 
 Y 
 
 v 
 
 C 
 
 \/ 
 
 COH 
 
 CO 
 
 *CH 
 
 4 
 
 *CH 
 
 *CH 
 
 *CH 
 
 /\^ 
 
 /\ 
 
 y\ 
 
 x\ 
 
 /\ 
 
 H 2 C CH 2 
 
 H 2 C CH 2 
 
 H 2 C CH 2 
 
 H 2 C CH 2 
 
 H 2 C CH 2 
 
 1 1 > 
 
 1 1 
 
 > | | 
 
 -> 1 1 ' 
 
 -> 1 1 
 
 H 2 C CH 
 
 HC CO 
 
 H 2 C CHOH 
 
 H 2 C CHOH 
 
 H 2 C CHOH 
 
 v 
 
 C 
 
 Y 
 
 "cH 
 
 Y 
 
 Yc 
 
 CH 3 
 
 U 
 
 CH 3 
 
 CH 3 
 
 CH 3 
 
 Limonene 
 
 Carvone 
 
 Dihydro-carveol 
 
 (i) 
 
 (2) 
 
 
 
 C0 2 H 
 
 CO 2 H 
 
 
 /\ /\ 
 
 H 2 C CH 2 HC CH 
 
 H 2 C CHOH 
 
 :H S 
 
 (3) (4)- 
 
 2. 1, 2, 8-Trioxy-hexahydro-cymol, dioxy-terpineol C 10 H 17 (OH) 3 , 
 melting at 122, formed from the terpineol melting at 35, passes into 
 carvenone when it is acted upon with dilute sulphuric acid (A. 277, 122). 
 
 3. 1, 8, 9-Trioxy-hexahydro-eymol C 10 H 17 [i, 8, 9](OH) 3 , m.p. 118, 
 from /3-terpineol. 
 
 4. 1, 4, 8 - Trioxy - hexahydro - cymol C 10 H 17 [i, 4, 8] (OH) 3 + 3 H 2 O, 
 melts in the anhydrous state at iio-ii2 and boils at 200 (20 mm.). 
 It is formed from A 4>8 -terpineol (B. 28, 2296). 
 
 5. 1, 2, 4-Trioxy-hexahydro-cymol (i) C 10 H 17 [i, 2, 4](OH) 3 +H 2 O, 
 m.p. 117, anhydrous, m.p. 129, and 
 
 6. 1, 3, 4-Trioxy-hexahydro-eymol (2) C 10 H 17 [i, 3, 4](OH) 3 , m.p. 
 121, are formed by the oxidation of terpinenol-4 and terpinenol-i. On 
 heating with HC1 the former passes into carvenone (3) and the latter 
 into A 1 -menthenone (4). KMnO 4 oxidises both to aaj-dioxy-a- 
 methyl-ai-iso-propyl-adipinic acid (5). These transformations, im- 
 portant for the constitution of terpinenols and terpinene-terpin, are 
 shown in the following scheme (A. 356, 207 ; 362, 261) : 
 
 (3) CH 3 (i)CH 3 OH ( 5 )CH 3 OH (2) CH 3 OH (4) CH 3 
 
 CH C C V C 
 
 H 2 C CO 
 
 H 2 C CHOH 
 
 H 2 C COOH 
 
 H 2 C CH 2 
 
 H 2 C CH 
 
 1 1 - 
 
 -II > 
 
 1 1 <- 
 
 II' 
 
 -> 1 1 
 
 HC CH 2 
 
 H 2 C CH 2 
 
 H 2 C COOH 
 
 H 2 C CHOH 
 
 H 2 C CO 
 
 Y 
 
 Y 
 
 v 
 
 C 
 
 Y 
 
 ""CH 
 
 ^H 
 
 L^rt, 
 
 S\ 
 
 HO CgH, 
 
 s\ 
 
 HO CsH, 
 
 H 7 Cg OH 
 
 CsH, 
 
502 ORGANIC CHEMISTRY 
 
 Tetra-acid-methane alcohols are formed by the oxidation of 
 some terpenes with potassium permanganate : (i) Limonetrite C 10 H 16 
 (OH) 4 , m.p. 192, from d-limonene (B. 23, 2315 ; 28, 2149) ; (2) erythrite 
 of terpinolene, m.p. 150 (anhydrous) (A. 368, 10) ; (3) erythrite from 
 y-terpinene, m.p. 237, gives a mixture of carvacrol and thymol on 
 heating with dilute H 2 SO 4 (A. 362, 298 ; C. 1909, II. 2159). 
 
 II. Menthene Alcohols C 10 H 17 . On oxidation with potassium per- 
 manganate these give three-acid alcohols (see above). 
 
 Terpineols. The " liquid terpineol " used in perfumery, obtained 
 from terpin hydrate by elimination of 2H 2 O with dilute H 2 SO 4 , consists 
 chiefly of the two isomeric a- and /?-terpineols, m.p. 35 and 32. 
 
 a-Terpineol, fr-menthenol-S CH 3 .C^ CH " ~ CH2 ^>CH.C(OH)(CH 3 ) 2 , m.p. 
 
 (optically inactive form) 35, (active forms) 37-38, b.p. 219, D 15 
 0-939, can also be obtained from linalool and geraniol. By nuclear 
 synthesis it is obtained through the action of methyl-magnesium iodide 
 upon A 1 -tetrahydro-p-toluic ester (C. 1909, I. 170). Terpineols, of 
 various origins, may be either active or inactive optically (B. 28, 2180). 
 A specially strongly laevo-rotatory a-terpineol, a D = 106, is obtained 
 by the action of dilute H 2 SO 4 upon methyl-nopinol (A. 360, 88). On 
 a laevo-rotatory terpineol from oil of turpentine, see C. 1889, I. 1241. 
 Terpineol combines very readily with nitrosyl chloride. When 
 hydrogen chloride is withdrawn from this body, an oxy-oxime, melting 
 at 134, is produced. Boiling dilute acids change it to carvacrol and 
 carvone (B. 29, R. 587). Hence it follows that in terpineol and carvone 
 the carbon atoms are similarly grouped. Terpineol nitroso-chloride 
 and limonene nitroso-chloride are correspondingly constituted (B. 29, 
 9). Potassium permanganate oxidises terpineol (i) into trioxy-hexa- 
 hydro-cymene, melting at 121 (2), while with chromic acid it yields a 
 ketone-lactone, homo-terpenylic acid methyl-ketone C 10 H 16 O 3 (3), 
 which, under the influence of potassium permanganate, breaks down 
 into acetic acid and terpenylic acid (4). Therefore, in terpineol melting 
 at 35, the OH group probably is in union with carbon atom 8 (B. 28, 
 1773, 1779) : 
 
 (CH 3 ) 2 (CH 3 ) 2 
 
 (i) C(OH) (2) C(OH) 
 CH CH 
 
 /\ /\ 
 
 H 2 C CH 2 H 2 C CH 2 
 
 H 2 C CH " * H 2 C CH(OH) 
 
 C COH 
 
 CH 3 CH 3 
 
 When terpineol is heated with potassium bisulphate it changes to 
 dipentene, and when boiled with oxalic acid to terpinolene (A. 275, 
 104; 368,io). 
 
 j3-Terpineol, & s W-menthenol-i CH 3 C(OH)<(^ CH2 ' H2 \CH.c^ /CH " 2 ( 
 
 \CH 2 CH 2 / \CH 3 ' 
 
 m.p. 32, b.p. 210, D 15 0-923; nitroso-chloride, m.p. 103 (A. 345, 
 127), yields with permanganate i, 8, g-trioxy-hexahydro-cymol, which 
 on further oxidation with chromic acid yields 4-acetyl-i, i-methyl- 
 cyclo-hexanol ; the latter may be converted into tetrahydro-p-acetyl- 
 
MONOCYCLIC TERPENE OR MENTHANE GROUP 503 
 
 toluol, p-acetyl-toluol, and p-toluic acid (B. 35, 2147 ; A. 324, 79). 
 For synthesis of /?-terpineol, see C. 1904, II. 330. 
 
 y-Terpineol, AW-menthenol-i CH 3 .C(OH)/ CH2 ~ ; H 2\c=c/ CH3 , 
 
 \CH 2 CH 2 / \CH 3 ' 
 
 melts at 69. Its acetate results on treating tribromo-terpane or tetra- 
 hydro-dipentene tribromide with glacial acetic acid and zinc dust. 
 Glacial acetic acid and HC1 convert it into a mixture of dipentene and 
 terpinene dichlorohydrate (A. 350, 160). With NOC1 it forms a blue 
 nitroso-chloride, just as tetramethyl-ethylene does. Consequently it 
 probably also contains a tertiary-tertiary double union. In addition, 
 its OH group must be in such a position that dipentene dihydro- 
 bromide can be produced with hydrogen bromide. 
 
 Terpinenols. As from terpin, so also from terpinene-terpin, un- 
 saturated alcohols may be obtained, by splitting off one molecule of 
 water. These are termed terpinenols (A. 356, 206 ; 362, 261). 
 
 Terpinenol-4, AJ-menthenol-4 CH S C/ C ; H2 \C(OH).CH/ CH 3, b.p. 
 
 \CH 2 CH 2 / \CH 3 
 
 212, found in dextro-form in cardamomene and majoran oil 
 (A. 356, 168). d-Terpineol-4 is formed by shaking up sabinene and 
 thujene in dilute H 2 SO 4 , sabinene hydrate being formed intermediately, 
 and easily passing into terpinenol-4. i-Terpinenol-4 is produced by 
 the action of dilute potash upon terpinene dihydro-chloride, and from 
 terpinene-terpin with aqueous oxalic acid. With glacial acetic hydro- 
 gen haloids it yields terpinene dihaloids, with dilute H 2 SO 4 terpinene- 
 terpin. By oxidation with MnO 4 K we obtain the I, 2, 4-trioxy-hexa- 
 hydro-cymol. 
 
 Terpinenol-1, &>-menthenol-i CH 3 .C(OH) 2 c.CHa, b.p. 
 
 \CH 
 
 209, is found in the first samples of industrial terpineol. It is 
 synthesised from A 3 -iso-propyl-cyclo-hexanone with methyl-mag- 
 nesium iodide. On oxidation it yields I, 3, 4- trioxy-hexahydro- 
 cymol. 
 
 Dihydro-carveol, ^-menthenol-2 
 
 b.p. 224, D 15 0-937, n D = 1-482, optically active, with a pleasant odour 
 recalling terpineols, was found in carraway oil (C. 1905, I. 1470) ; it is 
 formed by the reduction of carvone ; dihydro-carveol-xanthogenic 
 methyl ester on dry distillation yields d-limonene (C. 1908, I. 1180). 
 
 Iso - pulegol, W>-menthenol - 3 
 
 b.p. 13 91, from the isomerisation of citronellal with acids. On oxida- 
 tion it passes into the ketone, iso-pulegone. 
 
 A 3 -Menthenol-8 CH 3 CH/^ 2 - V qoH)/^ m p> ^ } b . p 
 
 Nv^rl 2 L/xl 2 / \Uxl 3 
 
 97, by the action of CH 3 MgI upon A 3 -tetrahydro-p-toluic ester or 
 A 3 -tetrahydro-p-acetyl-toluol (C. 1910, II. 80). 
 
 A 2 -Menthenol-l CH 3 (OH)C/^ =CH \ CH .cH/3 j b>p . io ^^ by 
 
 \Uxl 2 L/xl 2 / X ^*1 3 
 
 transposition of A 2 -iso-propyl-cyclo-hexenone-4 with CH 3 MgI. Easily 
 loses water and forms a-phellandrene (A. 359, 283). 
 
 Menthadiene Alcohols. Carveol-methyl ether C 10 H 15 OCH 3 , boiling 
 at 2o8-2i2, with sp. gr. 0-9065, n D = 1-47586 (18), represents the 
 methyl ether of such an alcohol. It is formed in the action of 
 
504 ORGANIC CHEMISTRY 
 
 sodium upon the alcoholic solution of limonene tetrabromide. Chromic 
 acid oxidises it to inactive carvone (A. 281, 140). 
 
 3. BASES OF THE MONOCYCLIC TERPENE OR MENTHANE GROUP. 
 
 Menthane bases have been obtained by the reduction of the oximes 
 of the methane-ketones with sodium and alcohol, or upon heating the 
 ketones with ammonium formate. 
 
 d-Menthylamine and 1-menthylamine CH 3 .CH/ CH2 ~ C \CH.CH(CH 3 ) 2 , 
 
 \CH 2 CH 2 / 
 
 boiling at 205, have an unpleasant odour, and attract CO 2 from 
 the air. The bases have opposite, but unequal, rotatory power ; 
 the same is true of their derivatives (A. 276, 299). They can be 
 separated by means of their formyl compounds, both of which are 
 formed on heating menthene with ammonium formate. d-Formyl- 
 menthylamine, melting at 117, dissolves with more difficulty. 
 1-Formyl-menthylamine melts at 102. 1-Menthylamine can also be 
 obtained from 1-menthoxime. With HNO 2 , 1-menthylamine passes 
 straight into 1-menthol, while d-menthylamine mostly forms menthene 
 (conclusions as to configuration, see A. 300, 278 ; 353, 323). On 
 treating the bromyl compounds of menthylamines with Ag 2 O, 
 1-menthylamine yields 1-menthyl-hydrazin C 10 H 19 NHNH 2 , b.p. 241, 
 while d-menthylamine forms menthazin C 10 H 18 : N.N : C 10 H 18 , m.p. 51 
 (C. 1900, I. 654). l-Menthyl-hydrazin is useful for splitting up racemic 
 aldehydes and ketones (B. 36, 1192). 1-Menthyl-carbimide C 10 H 19 .N : 
 CO, b.p. 12 110, from 1-menthylamine, chloro-carbonic ester, and 
 distillation of the resulting menthyl-carbaminic ester with P 2 O 5 . May 
 be used for splitting up racemic alcohols (C. 1904, II. 332). 
 Tetrahydro-carvylamine, carvo-menthylamine 
 
 CH 2 -- CH 2 
 boils at 212 (A. 277, 137 ; C. 1908, I. 733). 
 
 Tert. menthylamine CH 3 .CH/^ ^ 2 \C(NH 2 )CH(CH 3 ) 2 and tert. 
 
 \CH 2 CH 2 / 
 
 carvo-menthylamine CH 3 (NH 2 )C/ 2 2 \CH.CH(CH 3 ) 2 have been 
 
 \CM 2 CJrl 2 / 
 
 obtained by the interaction of menthene hydrobromide, carvo-rrtenthene 
 hydrobromide, and silver cyanate, with subsequent saponification 
 (B. 26, 2270, 2562). 
 
 2, 4-Diamido-menthane C 10 H 18 (NH 2 ) 2 , b.p. 12 121, from carvenone- 
 oxamine oxime (B. 41, 2528). 
 
 Menthene bases have been prepared by the reduction of the oximes 
 of menthene-ketones. Carvenylamine C 10 H 17 NH 2 , b.p. 10 86-89, from 
 carvenone oxime with Al amalgam. Its chlorohydrate yields a-ter- 
 pinene on distillation (B. 41, 2524). 
 
 Dihydro-earvylamine C 10 H 17 NH 2 , b.p. 219, with sp. gr. 0-889 (20), 
 n D =1-48294, is optically active, and is obtained from carvonoxime 
 C 10 H 14 : NOH. Its chlorohydrate breaks down completely at 200 into 
 cymol and terpinene, with migration of linkage (A. 368, 13). 
 
 Pulegonamine (A. 262, 13 ; B. 29, R. 173). 
 
 Nitrolamines have been obtained from nitroso-chlorides e.g. 
 limonene by transposition with primary and secondary bases. 
 
MONOCYCLIC TERPENE OR MENTHANE GROUP 505 
 
 4. THE RlNG-KETONES OF THE MONOCYCLIC TERPENE 
 
 OR MENTHANE GROUP. 
 
 Ketones like these are found in the vegetable kingdom. They are 
 produced by the oxidation of the corresponding secondary alcohols, 
 and by continued oxidation they change to cyclic and aliphatic car- 
 boxylic acids decomposition products, the constitution of which 
 furnishes insight into the constitution of the ring-ketones and their 
 derivatives. The ring-ketones of the terpane group, like other ketones, 
 are characterised by their oximes and the sparing solubility of their 
 semi-carbazones. 
 
 (a) Keto-menthanes, keto-hexahydro-p-cymols C 10 H 18 O. 
 
 Menthone CHg.CH/* CO\ CH .CH(CH 3 ) 2 , boiling at 208, sus- 
 
 XCH^.Crij/ 
 
 tains the same relation to menthol that camphor bears to borneol. 
 It occurs in Japanese, American, and Russian peppermint oils, together 
 with menthol, esters of menthol, menthene, and limonene. Menthone 
 is known in two optically active modifications. 1-Menthone is obtained 
 upon oxidising menthol with potassium bichromate and sulphuric acid 
 at a temperature not exceeding 50 (A. 250, 322). Its specific gravity 
 equals 0-896 (20), [a] D = 28. Concentrated sulphuric acid, in the 
 cold, rearranges 1-menthone to d-menthone, [a] D =+93-2 (B. 42, 846). 
 
 A d-menthone, [a] D =+43 66', is found in the American polei oil 
 from Hedeoma pulegioides (C. 1907, II. 242). Synthetically, i-menthone 
 has been formed from jS-methyl-pimelinic ester by cyclic aceto-acetic 
 ester condensation, introduction of the iso-propyl group, and saponi- 
 fication (B. 34, 3793). 
 
 An optically active men th one is formed from the active I, 3-methyl- 
 cyclo-hexanone obtained by breaking up pulegone, by treating with 
 sodium amide and iso-propyl iodide (C. 1905, I. 605) ; for other syn- 
 theses of menthone, see A. 342, 306 ; 357, 209 ; also Rhodinal. 
 
 The constitution of menthone is demonstrated (i) by its conversion 
 into 3-chloro-cymol ; PC1 5 changes menthone to dichloro-hexahydro- 
 cymol, which splits off hydrogen chloride and becomes tetrahydro-chloro- 
 cymol ; this in turn, by the action of bromine and quinolin, loses 
 hydrogen, and 3-chloro-cymol results (B. 29, 314). (2) By the formation 
 of thymol through the elimination of 2HBr from dibromo-menthone 
 C 10 H 16 Br 2 O, melting at 80, which is produced in the bromination of 
 menthone in chloroform solution (B. 29, 418). 
 
 When 1-menthone is reduced by sodium it forms I -menthol, 
 while with ammonium formate the product is L - menthylamine. 
 Potassium permanganate oxidises it to oxo-menthylic acid 
 
 CH 3 .CH/ 2 -^ 2H / co - CH ( CH 3) 2 > and &-methyl-adipic acid (B. 27, 1820). 
 
 >vx-H.2.CxAjL2. * 
 
 Caro's acid produces the e-lactone of dimethyl-octanolic acid 
 
 CH ' CH <CH;=H~?H.CH(CH 3 ) 2 < B - 27 > I82 ; 32 ' 3621; 33, 860); 
 dilute nitric acid produces nitro-menthone, which can be reduced to 
 amido-menthone (C. 1898, II. 301). 
 
 Amyl nitrite and hydrochloric acid convert menthone into nitroso- 
 menthone and menthoximie acid, melting at 98. This is the oxime 
 of oxo-menthylic acid (B. 29, 27). 
 
 Illumination of an aqueous alcoholic solution of menthone leads 
 
506 ORGANIC CHEMISTRY 
 
 to the splitting of the ring and produces decylic acid (CH 3 ) 2 CH.(CH 2 ) 3 
 CH(CH 3 )CH 2 COOH, and an aldehyde C 10 H 18 O, possibly identical with 
 a mentho-citronellal obtained by a transformation of menthone-oxime 
 (B. 40, 2419) 
 
 Sodium and amyl formate change menthone to oxy-methylene- 
 menthone, boiling at 121 (12 mm.). 
 
 Benzylidene-menthone, m.p. 51, b.p. 12 189, gives, on reduction 
 benzyl-menthone, b.p. 10 i75-i78 (B. 37, 232) . With sodium and CO 2 , 
 in ether solution, menthone gives menthone-mono- and dicarboxylie 
 acids (C. 1897, 11.759). 
 
 1-Menthone-oxime, m.p. 61, b.p. 250, [a] D = 42, is transposed 
 into 1-menthone-isoxime by PC1 5 in chloroform, or by acetic anhydride, 
 or by concentrated H 2 SO 4 . The substance formed is the e-lactame of 
 an e-amido-methyl-iso-propyl-capronic acid, m.p. 119, b.p. 295, [a] D 
 === _ 5 2-25 . With.P 2 O 5 both bodies yield mentho-nitrile C 9 H 17 CN, 
 b.p. 225, which, on saponification, passes into the liquid menthonenic 
 acid C 9 H 17 COOH ; the latter is constituted somewhat like citronellic 
 acid, but is not identical. The menthonylamine produced by the 
 reduction of mentKb-nitrile yields with HNO 2 a mentho-citronellol 
 closely related to citronellol (A. 296, 120). 
 
 Tetrahydro-carvone CH 3 .CH./^-^ 2 \CH.CH(CH 3 ) 2 , with sp. gr. 
 
 NL/.H.2. 1^X1-2' 
 
 0-904 (20), n D =i-45539, is produced in the oxidation of tetra- 
 hydro-carveol and by reduction of carone with Na in moist ether. 
 Benzylidene compound, m.p. 175 (A. 305, 266). The oxime melts at 
 104, the a-isoxime at 51. f$-Isoxime melts at 104. The semi-car- 
 bazone melts at 174 (A. 277, 133 ; 286, 107 ; B. 26, 822). When oxid- 
 ised with potassium permanganate or treated with amyl nitrite and 
 hydrochloric acid, tetrahydro-carvone is decomposed like menthone 
 
 with the production of an acid, CHg.CO^^ "^^CH.CgH^ j8-tso- 
 
 propyl-^-acetyl-valeric acid, isomeric with oxo-menthylic acid. Ener- 
 getic oxidation produces iso-propyl-succinic acid (B. 29, 27). 
 
 With Caro's acid we obtain the e-lactone of iso-propyl-heptanolic 
 
 (b) Keto-menthenes C 10 H 16 O occur to a certain extent in nature, 
 others are produced by the oxidation of the corresponding alcohols. 
 They contain one double union. 
 
 A 3 -Methene-5-ketone CH 3 CH<^* ^Vc,*^ b.p. 213, D 20 0-918, 
 
 n D =*i-472O ; its oxime, nitroso-menthene, is obtained from menthene 
 nitroso-chloride by splitting off HC1 (A. 305, 272 ; 362, 275). 
 
 A^Menthene-S-ketone CHgC^^^j^CHC^H,, b.p. 236, semi- 
 
 carbazone, m.p. 225, has been found in Japanese peppermint oil ; it 
 is formed besides cymol on heating 1,3, 4-trioxy-hexahydro-cymol 
 with HC1 (A. 362,271). 
 
 Dihydro-carvone, b?W-menthene-2-on CH 3 CH/CH 2 CH 2 \ CH 
 
 \CO CH 2 / 
 
 b.p. 221, D 19 0-928, n D =i-47i74, was found in carraway oil (C. 1905, 
 I. 1470) ; the d- and 1-forms are produced from the corresponding di- 
 hydro-carveols by oxidation, or direct by the reduction of the carvones 
 
MONOCYCLIC TERPENE OR MENTHANE GROUP 507 
 
 with zinc dust and alcoholic potash (A. 279, 377). Benzylidene com- 
 pound, b.p. 10 i87-i90 (A. 305, 268). 
 
 The oximes melt at 88, and unite to the inactive [d-\-l\-oxime, melt- 
 ing at 115. Boiling ferric chloride converts dihydro-carvone into 
 carvacrol ; cp. carvenone and carone. Oxidation with potassium 
 permanganate and afterwards with chromic acid changes it to 2, 5- 
 methyl-acetyl-cyclo-hexanone (B. 28, 2147, 2704). On the decom- 
 position of dihydro-carvone by light, see B. 41, 1928. 
 
 Carvenone, carveol, &?-menthene-2-on CH 3 
 
 b.p. 232, D 0-927, ^'=1-4822, results from I, 2, 8- and I, 2, 4-trioxy- 
 hexahydro-cymol on heating with dilute sulphuric acid besides cymol ; 
 by isomerising dihydro-carvone and carone with mineral or formic acids ; 
 by treating camphor, or rather dichloro-camphane, with HgSO^; and 
 by reduction of a-terpinene nitrosite with zinc and glacial acetic acid 
 (/. pr. Ch. 2, 60, 261 ; A. 314, 369). Oxime, m.p. 91. Hydroxyl- 
 amino-oxime, m.p. 163 (B. 31, 2896). Semi-carbazone, m.p. 202. It 
 is closely related to carvo tan-acetone. Boiling ferric chloride oxidises 
 carvenone to carvacrol, while heating with P anhydride produces 
 cymol, and permanganate a-methyl-glutaric acid (A. 314, 380). 
 With PC1 5 it produces monochloro - carvenene C 10 H 15 C1, b.p. 10 
 95-98, which on reduction with Na and alcohol yields a-terpinene 
 (B. 41, 4477). 
 
 Carvotan-acetone, ^-menthene-6-on 
 
 b.p. 228, D 21 0-938, n D =1-47926, results in an inactive form from the 
 heating of thujone (tanacetone) to 280. Its oxime melts at 92, and 
 its semi-carbazone at 177 (B. 28, 1959). Optically active dextro- 
 and laevo-rotatory carvotan-acetone, [a] D +i9-2, is obtained by 
 careful reduction of a-phellandrene nitrite (A. 336, 39). Its oxime 
 melts at 72, its semi-carbazone at 173. A dextro-rotatory carvotan- 
 acetone has also been obtained from carvone hydrobromide by reduc- 
 tion with zinc dust and methyl alcohol (B. 34, 1924). With H 2 S it 
 combines like carvone to form the compound (C 10 H 16 O) 2 H 2 S, m.p. 220. 
 On oxidation with MnO 4 K it yields pyro-racemic acid and iso-propyl- 
 succinic acid (B. 33, 2457). With PC1 5 it gives monochloro-phellan- 
 drene C 10 Hi 6 Cl, b.p. 15 108, which, with zinc dust and methyl alcohol, 
 is reduced to a-phellandrene (B. 38, 1832). 
 
 Pulegon, b^^-menthene-^-ketone CH 3 .CH<^;2 2 ~~? N X=C(CH 3 ) 2 , b.p. 
 
 \Crl 2 L/ri 2 / 
 
 221, D 0-936, n D =1-4846, is contained in the ethereal oil of Meniha 
 pulegium and Hedeoma pulegioides, which are sold under the name 
 polei oil. By the addition of hydrogen, pulegone is converted into 
 menthone ; by oxidation, into jS-methyl-adipinic acid and acetone ; and 
 by heating with formic acid or with water under pressure, into acetone 
 and 3-methyl-cyclo-hexanone, which on oxidation also yields jS-methyl- 
 adipinic acid : 
 
 If, on the other hand, methyl-cyclo-hexanone and acetone are 
 
508 ORGANIC CHEMISTRY 
 
 condensed, by means of alkalies, we obtain a geometrically isomeric 
 pulegone boiling at 215 (A. 300, 267). 
 
 If pulegone dibromide (i) is boiled with sodium methylate solution, 
 we get pulegenic acid (2) C 10 H 16 O 2 , in which case the six-membered 
 ring system is probably converted into a five-membered system. Oxi- 
 dation with potassium permanganate converts the pulegenic acid into 
 an oxy-lactone (3), which on heating with half-saturated sulphuric acid 
 is converted into pulenone (4) or 3, 6, 6-trimethyl-cyclo-hexanone, 
 with elimination of CO 2 and ring expansion, and an atomic dis- 
 placement quite analogous to the pinacolin transposition (A. 329, 82 ; 
 cp. also A. 376, 154) : 
 
 CH 3 CH 3 
 CH 3 CH 3 
 
 , V (2) C (3) C -- O (4) CH 3 CH 3 
 
 (i) CBr 
 
 CBr C 
 
 /\ 
 
 H 2 C CO _ H 2 C CHCOOH _ _ H 2 C CH.CO H 2 C CO 
 
 H 2 C CH 2 > H 2 C CHCH 3 > H 2 C CHCH 3 > H 2 C CH 2 
 
 v \/ 
 
 CH CH 
 
 CH 3 
 
 From pulegenic acid the hydrocarbon pulegen C 9 H 16 , b.p. 139, 
 D 0-791, is formed by rejection of CO 2 . Its nitroso-chloride can be 
 converted into pulegenone C 9 H 14 O, b.p. 190, a ketone closely related 
 to camphor-phorone (A. 327, 125). 
 
 Pulegone combines, like other a/?-unsaturated ketones, with sodium- 
 malonic ester (A. 345, 158, 188) and potassium cyanide (C. 1907, 1. 721). 
 
 Benzylidene-pulegone, b.p. 203 (A. 305, 267) : by the action of 
 hydroxylamine upon pulegone in the presence of alkali, we obtain iso- 
 pulegone-oxime with displacement of linkage. Under other conditions 
 we obtain the hydroxylamine addition product, pulegone-hydroxyl- 
 amine C 10 H 17 O(NHOH), m.p. 157, which yields on oxidation nitroso- 
 menthone, m.p. 35, and by reduction amido-menthone (B. 31, 1809 J 
 32, 3365), as well as pulegone-hydroxylamine-oxime C 10 H 17 (NHOH) 
 ( : NOH), m.p. 118, which is reduced with sodium and alcohol to 
 3, 8-diamido-menthane (B. 38, 146). 
 
 Iso-pulegone, ^(^-menthene-^-ketone CH 3 CH<^ 2 ~^ NcHC^^ 2 , 
 
 \CH 2 CH 2 / \CH 2 
 
 b.p. 14 103, is obtained from its oxime, m.p. 120, on heating with 
 oxalic acid (A. 365, 24), from pulegone hydrobromide with basic lead 
 nitrate, or by oxidising its alcohol, iso-pulegol, the isomeric product 
 of citronellal. It contains two unsym. C atoms, and therefore occurs 
 in several geometrically isomeric optically active modifications. By 
 treatment with baryta water it is converted back into pulegone (B. 32, 
 3357)- 
 
 2-Oxy-A 1 -menthene-3-ketone CH^^-^VH.CH/^ m.p. 
 
 \CH 2 - CH 2 / \CH 3 
 
 84, b.p. 10 110, is probably represented by the bucco-camphor or dios- 
 phenol obtained from bucco leaves (Barosma). In its behaviour it 
 shows both ketone and phenol character. With ferric chloride it gives 
 a green coloration, it has an acetate and a benzoate, forms with 
 phenyl-iso-cyanate a phenyl-urethane, m.p. 41, and with hydro xyl- 
 
MONOCYCLIC TERPENE OR MENTHANE GROUP 509 
 
 amine a monoxime, m.p. 125. On heating with concentrated HC1 it 
 is converted into thymol, and a little carvacrol.' On oxidation with 
 ozone we obtain a-iso-propyl-y-acetyl-butyric acid ; and on reduction 
 with sodium and alcohol, 2, 3-dioxy-hexahydro-cymol, which is oxidised 
 by permanganate to a-methyl-a-iso-propyl-adipinic acid. Syntheti- 
 cally, bucco-camphor is formed by oxidation of oxy-methylene- 
 menthone with ozone (B. 39, 1158). 
 
 (c) Menthadiene-ketones, keto-dihydro-p-cymols C 10 H 14 O. The most 
 important member of this group is carvone, formerly called carvol. 
 Its importance is due to its intimate relationship to carvacrol and 
 limonene, which are isomeric with it. Carvone is known in three 
 modifications, the d-, 1-, and [d+1]-. 
 
 d-Carvone CH 3 .c^;^C.CH(CH 3 ) 2 (3. 28, 31), or 
 
 (B. 28, 2145), [a] D =-f-62 , boiling at 225, occurs in carraway oil and 
 in dill oil. When heated with potassium hydroxide or phosphoric 
 acid it changes to isomeric carvacrol or 2-methyl-5-iso-propyl-oxy- 
 benzol ; hence it is assumed that in carvone the CO group, like the 
 OH group in carvacrol, is in the ortho-position with reference to the 
 methyl group. With PC1 5 carvone forms a dichloride C 10 H 14 C1 2 , which 
 on distillation with quinolin yields 2-chloro-cymol (B. 32, 2555). 
 Reduction changes it to dihydro-carveol, while ammonium formate 
 converts it into dihydro-carvylamine. Potassium permanganate 
 oxidises carvone to oxy-terpenylic acid C 8 H 12 O 5 , which easily changes 
 to a dilactone C 8 Hi O 4 , melting at 129 (B. 27, 3333 ; 28, 2148). 
 The carvones combine with hydrogen sulphide, hydrogen chloride, 
 hydrogen bromide, and bromine (B. 28, R. 548 ; A. 305, 235 ; 
 C. 1907, I. 568). *t)n the splitting up of carvone tribromide to car- 
 venolidene C 10 H 14 O 2 , see A. 305, 245. With sodium bisulphite we 
 obtain the sodium salt of carvone dihydro-sulphonic acid (C. 1900, I. 
 1155) . On shaking up with dilute H 2 SO 4 , carvone takes up one molecule 
 H 2 O and forms oxy-dihydro-carvone (carvone hydrate, B. 38, 1719 ; 
 39, 677). 
 
 With aceto-acetic ester carvone combines in the presence of sodium 
 alcoholate to a dicyclic condensation product (B. 36, 225). 
 
 1-Carvone, [a] D = 60, boiling at 230, occurs in mint oil and curo- 
 moji oil (B. 24, 81). It is obtained pure by distilling its hydrogen 
 sulphide compound, melting at 187, with caustic potash (A. 305, 224). 
 
 [d+1] -Carvone, boiling at 230, is formed on mixing d- and 1-carvone, 
 as well as by oxidising carveol-methyl ether. Formation from terpineol, 
 B. 29, R. 587. 
 
 The three carvones are linked through the three carvoximes to the 
 three corresponding limonenes. The carvoximes are prepared not only 
 by the action of hydroxylamine upon the carvones, but also upon boil- 
 ing the limonene nitroso-chlorides with alcoholic potash. d-Carvone 
 and 1-limonene correspond on the one side to each other, while on the 
 other 1-carvone and d-limonene correspond, inasmuch as 1-limonene 
 nitroso-chloride yields d-carvoxime, and d-limonene nitroso-chloride 
 1-carvoxime. 
 
510 ORGANIC CHEMISTRY 
 
 d-Carvoxime, [ a ] D = +39-71, and 1-carvoxime, [a] D = 39-34, 
 melt at 72. [d+l]-Carvoxime melts at 33, and is obtained from 
 dipentene nitroso-chloride. Concentrated sulphuric acid rearranges 
 carvoxime to p-amido-thymol (compare rearrangement of j8-phenyl- 
 hydroxylamine to p-amido-phenol, A. 279, 366). Hydroxylamino- 
 carvoxime C 10 H 15 (NOH).NHOH, a syrup, oxidises to form the di- 
 oxime of a diketone C 10 H 14 O 2 , m.p. i85-i87, which is also formed direct 
 from carvone by atmospheric oxidation in the presence of baryta, and 
 is probably I, ^-methyl-iso-propenyl-dihydro-resorcin (B. 34, 2105). 
 
 C. DICYCLIC TERPENE GROUP. 
 
 The terpenes of this group are distinguished from the monocyclic 
 terpenes by the fact that they can only add two univalent atoms or 
 atomic groups. They therefore contain two carbon rings. These di- 
 cyclic terpenes, and their derivatives containing oxygen, are joined 
 up with the monocyclic terpene compounds by numerous transitions. 
 Like the latter, they are closely related to p-cymol, and can usually be 
 converted into this with facility. 
 
 Their dihydro-compounds are derived from hexahydro-cymol either 
 by joining two carbon atoms in the m-position towards one another, 
 by a diagonal link, thus forming a compound of the trimethylene and 
 pentamethylene group. This gives the sabinane or tanacetane group. 
 Or, the tertiary carbon atom of the iso-propyl group is joined with a 
 second carbon atom of the hexamethylene ring. According as to 
 whether this link occurs in the o-, m-, or p-position, we get the funda- 
 mental hydrocarbons of the carane, pinane, and camphane groups : 
 
 CH 3 CH 3 CH 3 
 
 CH CH CH 2 CH 2 CH CH 2 CH 2 CH CH 
 
 (CH 3 ) 2 C 
 
 (CH 3 ) 2 C- 
 
 CH 2 CH CH 2 
 Sabinane Carane Pinane Camphane. 
 
 While these nuclear and bridge-linkages are stable as regards the 
 usual addition-reactions, and are thus clearly distinguished from 
 double linking, they are broken up with extraordinary facility by the 
 action of higher temperatures, but especially by hydrating agents, 
 giving rise to derivatives of the monocyclic terpenes. 
 
 I. SABINANE OR TANACETANE GROUP. 
 
 The closely related compounds of this group, the most important 
 representative of which is thujone or tanacetone, contain a compound 
 trimethylene and pentamethylene ring, and can be broken down by 
 oxidation into trimethylene-carboxylic acids. 
 
 i. Hydrocarbons. Sabinene and the two thujenes belong to these. 
 All three contain the same carbon skeleton, and only differ by the 
 position of the double linkage, since by gentle reaction they can be 
 transformed into the equally saturated dicyclic hydrocarbon C 10 H 18 , 
 i.e. sabinane or thujane (C. 1911, I. 313). 
 
 Sabinene (i) C 10 H 16 , b.p. i63-i65, D 20 0-842, n D 1-468, has been 
 
SABINANE OR TANACETANE GROUP 511 
 
 found in its dextro-rotatory form in Ceylon cardamom oil, majoran 
 oil, and pilea oil (A. 357, 77 ; B. 40, 2963). With quite dry HC1 in 
 CS 2 solution it yields terpinene monochlorohydrate, with glacial 
 acetic halogen hydride the corresponding terpinene-dihydro-haloids. 
 By dilute H 2 SO 4 it is converted, in the cold, into optically active 
 terpinenol-4 and terpinene-terpin, and with heat into a-terpinene. On 
 oxidation with KMnO 4 , sabinene behaves like most other terpenes 
 with semi-cyclically linked methylene group (cp. j8-pinene and cam- 
 phene). Sabinene-glycol (2) is first formed, m.p. 54, which is then 
 oxidised to an a-oxy-acid marked by its sparingly soluble sodium salt, 
 viz. sabineric acid (3), m.p. 57, and further to sabina-ketone (4), b.p. 
 212, containing one C atom less. The latter, on heating with aqueous 
 or alcoholic H 2 SO 4 , easily splits the trimethylene ring, and forms 
 A 2 -iso-propyl-cyclo-hexenone (6), and on further disintegration 
 a-tanacetone-dicarboxylic acid (5) (A. 359, 266 ; B. 35, 2045) : 
 
 CH 2 CH 2 OH COOH __ > 
 
 (i) C (2) COH (3) COH (4) CO (5) COOH (6)*CH 
 
 /\ /\ /\ /\ / /\ 
 
 HC CH 2 HC CH 2 HC CH 2 HC CH 2 HC COOH HC CH 2 
 
 H 2 C CHo^HaCl CH 2 "* H 2 C\ CH 2 ^H 2 C\ CH 2 ^H 2 C\ CH 2 HC CH 2 
 
 ^/ \/ N\/ \X 
 
 C C C CH 
 
 3^7 
 
 As already mentioned, sabina-ketone may be used for building up 
 jS-terpinene. 
 
 x/->TT _ PfT \ 
 
 a-Thujene CH.C-CC.H,, b.p. 152, D 20 0-8275, n D 1-4504, 
 
 and jS-thujene CH S CH<^ _ ~. -^C.GjH, (?), solid, b.p. 150, D 20 
 
 \CH CH 2 / 
 
 0-8248, n D 1-4484, have been obtained by distillation from the methyl- 
 xanthogenate of thujyl alcohol, and from thujylamine by thorough 
 methylation and by heating the resulting quaternary ammonium base 
 (B. 34, 2276 ; 37, 1481). On oxidation with KMnO 4 a-thujene yields 
 a-thuja-keto-acid (see below), and combines, with two molecules 
 halogen hydride, to form the corresponding terpinene-dihalogen 
 hydrates. On shaking up with dilute sulphuric acid it becomes, like 
 sabinene, active terpinenol-4 and terpinene-terpin (A. 350, 166 ; 356, 
 201). Isomeric with these two hydrocarbons is iso-thujene, b.p. 172- 
 175, D 0-840, n D 1-476, formed by the dry distillation of thujylamine- 
 chlorohydrate (A. 286, 99). 
 
 Sabinane, thujane, C 10 H 18 , b.p. 157, is formed by the reduction of 
 sabinene, a- and jS-thujene, with hydrogen in the presence of platinum 
 black (C. 1911, I. 313). 
 
 2. Alcohols. Sabinene hydrate, methyl-sabina-ketol 
 
 CH 3 \ /CH 2 CH.\ 
 
 m -P- 39> b.p. i95-20i, is formed besides 
 
 , 
 
 a-terpinene by the action of methyl-magnesium iodide upon sabina- 
 ketone. With glacial acetic hydrogen bromide it forms terpinene- 
 dibromo-hydrate, and, on shaking up with dilute sulphuric acid, an 
 optically active terpinenol-4 and terpinene-terpin (A. 357, 64). 
 
 " ~ 
 
 Thujyl-alcohol, tanacetyl-alcohol CH 3 CH 
 
512 ORGANIC CHEMISTRY 
 
 92-5, D 0-9249, n D 1-4635, is formed by reduction of thujone or tan- 
 acetone, into which it reverts on oxidation. It is found, partly free 
 and partly in the form of aliphatic esters, in wormwood oil (A. 272, 109). 
 
 Sabinol CH 2 =c/ C ^^C.CjH,, b.p. 211, D 20 0-9432, an 
 
 \CH CH 2 / 
 
 unsaturated secondary alcohol, found in the form of its ester in oleum 
 sabince. It is converted into cymol by dehydrating agents, into 
 tanacetone by short heating with zinc dust, and into tanacetyl-alcohol 
 by reduction with sodium and alcohol. Careful oxidation with 
 KMnO 4 converts it into sabinyl-glycerin C 10 H 15 (OH) 3 , m.p. 153, which 
 easily passes into cumin-alcohol by splitting off water ; strong oxida- 
 tion produces a-tanacetone-dicarboxylic acid (B. 33, 1191, 1459 ; cp. also 
 A. 360, 98). 
 
 3. Amines. Thujylamine C 10 H 17 NH 2 , b.p. 195, by reduction of 
 thujone oxime. On heating its chlorohydrate it yields iso-thujene. 
 
 4. Ketones. Thujone, tanacetone (i) C 1? H 16 O, b.p. 200, D 0-917, 
 n D = 1*4511, is found in two physically isomeric forms the laevo-rotatory 
 a-thujone, [a] D = 10-23, semi-carbazone, m.p. 186, oxime liquid, 
 chiefly in thuja oil; the dextro-rotatory j3-thujone, [a] D = +76-16, 
 semi-carbazone, m.p. 171 and 175, oxime, m.p. 55 chiefly in the 
 oil of Tanacetum vulgar e. Mixtures of both forms have been traced in 
 wormwood oil, sage oil, absinth oil, and the oil of Artemisia Barrelieri 
 (A. 336, 247). On oxidation with KMnO 4 both forms give the chemi- 
 cally isomeric a- and jS-thuja or tanaeeto-ketone-carboxylic acids 
 CH 3 CO.C 7 H 12 .COOH, m.p. 75 and 78, the a-acid being saturated and 
 the j8-acid unsaturated. On heating, the a-acid turns into the jS-acid, 
 the latter (2) being oxidised into a diketone (3), and then converted 
 into S-dimethyl-laevulinic acid (4). The a-tanaceto-ketonic acid (5) 
 is broken down, by bromine and alkali, to a-tanacetone-dicarboxylie 
 acid (6) C 9 H 14 O 4 , m.p. 142, a saturated dibasic acid, which easily 
 turns into anhydride, and is also formed by the oxidation of sabinol, 
 sabinene, and a-thujene : 
 
 CH 3 CH 3 CH 3 CH 3 
 
 (4) C0 2 H (3) CO (2) CO (i) C (5) CO (6) C0 2 H 
 
 H 2 C H 2 C H 2 C CO 2 H HC CO HC, CO 2 H HC CO 2 H 
 
 H 2 C *~H 2 C *~H 2 C CH ^H-jCl CHa^HsjCy CH 2 ~^H 2 C\CH 2 
 
 \ \ \S \/ \/ ' \1/ 
 
 CO CO C C C C 
 
 C 3 H 7 
 
 Condensation with benzaldehyde converts thujone into benzylidene- 
 thujone, b.p. 9 178, which is split up by potassium permanganate into 
 benzoic acid and homo-tanacetone-diearboxylic acid C 10 H 16 O 4 , m.p. 
 148. This acid, like a-tanacetone-dicarboxylic acid, and tanacetone 
 itself, probably contains the trimethylene ring (B. 36, 4367 ; but see 
 B. 33, 1192). 
 
 Thujone, treated with alcoholic sulphuric acid, turns into iso- 
 thujone. On heating to 280, it turns into carvo-tanacetone. These 
 two ketones are unsaturated, in contrast with thujone (B. 28, 1959). 
 Thujone-oxime, m.p. 54, with alcoholic sulphuric acid, turns into 
 carvacryl-amine (B. 30, 325) ; treatment with PC1 5 converts it into 
 the lactame-like thujone-isoxime, m.p. 90 (A. 336, 270). 
 
SABINANE OR TANACETANE GROUP 513 
 
 Iso-thujonecH,c< c ^ CH(CH)i (?), b.p. 231, D 0-927, n D = 
 
 1-4822, m.p. 119. a- and j8-Semi-carbazone, m.p. 208 and 148. 
 Oxime, m.p. 120. Benzylidene-isothujone (C 10 H 14 O) : CHC 6 H 5 , m.p. 
 83. When oxidised, iso-thujone yields a keto-lactone C 10 H 16 O 3 , and, 
 further, /S-iso-propyl-laevulinic acid CH 3 COCH(C 3 H 7 ).CH 2 COOH ; by 
 reduction a saturated alcohol is obtained, thuja-menthol, dihydro-iso- 
 thujol C 10 H 19 OH, b.p. 212, D 0-9015, n D = 1-4636, which, on oxidation 
 with chromic acid, forms thuja-menthone C 10 H 18 O, b.p. 208, D 0-891, 
 n D 1*447. Oxime, m.p. 95 ; isoxime, m.p. 117. All these compounds 
 are probably derivatives of cyclo-pentane (A. 323, 348 ; 336, 276 ; 
 B. 28, 1958). 
 
 ^CH - CO\ 
 
 Umbellulone CH 3 .c^ VfrH,, b.p. 10 93, [a] D -37. which 
 
 x Crl CJbij/ 
 
 occurs in profusion in the leaves of Californian laurel, Umbellularia 
 calif ornica. Semi-carbazone, m.p. 242. On heating to 280, it trans- 
 poses into thymol. Bromination and subsequent distillation produce 
 p-cymol and other brominated bodies. Sodium and alcohol reduce it 
 to the saturated alcohol C 10 H 17 .OH, b.p. 10 90, which, on oxidation 
 with chromic acid, turns into dihydro-umbellulone C 10 H 16 O, b.p. 10 85. 
 The benzylidene compound of the latter, on oxidation with KMnO 4 , 
 yields, like benzylidene- thuj one (see above), 1-homo-tanacetone-dicar- 
 boxylic acid (B. 40, 5017 ; 41, 3988). 
 
 CARANE, PINANE, AND CAMPHANE GROUP. 
 
 The derivatives of this group contain, as already stated, a hexa- 
 methylene ring, in which two carbon atoms in the o-, m-, or p-position 
 are joined together by means of a carbon bridge. In nature such 
 compounds have only been found with an m- or p-bridge. Among 
 the former we have pinene, extremely frequent in natural substances ; 
 and among the latter we have camphor, the most important derivative 
 in this group, and the closely related fenchone, as well as the derived 
 terpenes, camphene and fenchene. Characteristic of the compounds 
 of this group is the remarkable facility with which they undergo intra- 
 molecular transpositions under the influence of acid reagents. These 
 transpositions are sometimes accompanied by a complete change in the 
 ring system, which makes a recognition of the connection between the 
 products and the elucidation of their constitution extremely difficult. 
 
 Nomenclature. The names are mostly derived from botany, and 
 associated with the extraction of some of the more important sub- 
 stances. Only in a few cases does a systematic nomenclature appear 
 possible. Thus, the hitherto unknown demethylated hydrocarbon 
 corresponds to the three chief types of these groups, and designated by 
 nor-camphane, nor-pinane, and nor-carane, which are used as bases, 
 and their carbon atoms are given numbers as follows : 
 
 345 345 345 
 
 CH 2 CH CH 2 CH 2 CH 2 CH CH 2 CH 2 CH 2 
 
 7 CH 2 
 
 H 2 C 
 
 7 CH/ 
 
 H CH 2 CH 2 CH CH 2 CH 2 CH CH 
 
 216 216 216 
 Norcamphane Norpinane Norcarane. 
 
 VOL. II. 2 L 
 
5 i4 ORGANIC CHEMISTRY 
 
 II. CARANE GROUP. 
 
 The compounds of this group are ranged with the sabinane group, 
 since they also contain a trimethylene ring, which, however, is com- 
 bined with a hexamethylene ring. Hydrocarbons of this group, which 
 has only been investigated by synthesis, are unknown. 
 
 Garone (formula below), b.p. 15 100, is formed from dihydro-carvone 
 hydrobromide with alcoholic potash. It is comparatively stable 
 towards potassium permanganate, which only attacks it at water- 
 bath temperature, and oxidises it to caronic acid, or i, i-dimethyl-2, 3- 
 trimethylene-dicarboxylic acid (i). On the other hand, the trimethy- 
 lene ring of carone can be split up in three different places : (i) 
 Splitting between C 6 and C 7 ; on heating to about 210 carone trans- 
 poses into carvenone (2) (B. 32, 1222) ; HBr turns it into dihydro- 
 carvone hydro-bromide, and sulphuric acid into oxy-tetrahydro-carvone. 
 (2) Splitting between C x and C 7 ; the carylamine C 10 H 17 NH 2 , stable in 
 the presence of KMnO 4 , obtained from carone-oxime, m.p. 78, by 
 reduction transposes, in the presence of HC1, into the isomeric un- 
 saturated vestrylamine (3), whose chlorohydrate, on heating, yields 
 carvestrene (B. 27, 3486). (3) Splitting between C t and C 6 ; the 
 cyano-carone C 10 H 15 (CN)O, m.p. 55, obtained from cyano-dihydro- 
 carvone hydro-bromide with alcoholic potash, which can also be 
 disintegrated to caronic acid, yields, on heating with alcoholic potash, 
 eucarvone (C. 1910, I. 924). 
 
 An oxy-earone C 10 H 1? O 2 , b.p. 19 135, has been obtained by starting 
 from dihydro-carvone dibromide ; the latter, with soda, yields oxy- 
 bromo-tetrahydro-carvone, which, on treatment with methyl-alco- 
 holic potash, turns into oxy-carone ; on digesting the latter with 
 dilute sulphuric acid it is turned into a ketone derivative of terpin 
 (B. 31, 3208). 
 
 A constitution and transformations similar to those of carone are 
 shown by pseudo-phenyl-acetic acid, or nor-caradiene-carboxylic acid, 
 obtained from benzol and diazo-acetic ester. 
 
 Eucarvone (formula 4 above), b.p. 12 86, D 20 =o*952, 110=1-5048 
 (A. 339, 94), probably belongs to the heptacarbocyclic compounds, but 
 is treated here on account of its relation to carone. It is formed from 
 carvone hydro-bromide with alcoholic potash, evidently with inter- 
 mediate formation of the unstable a/S-unsaturated carone (cp. the 
 transition of cyano-carone into eucarvone). It is optically inactive. 
 On boiling down with methyl-alcoholic potash, it gives a deep-blue 
 unstable coloration. Semi-carbazone, m.p. 184 ; oxime, m.p. 106 ; 
 oxamino-oxime, m.p. 142 (A. 330, 275). It unites with benzaldehyde 
 to form benzylidene-eucarvone, m.p. 113. On oxidation it yields 
 acetic acid and unsym. dimethyl-succinic acid. On reduction with 
 Na and alcohol we get, simultaneously, dihydro-eucarveol C 10 H 17 OH, 
 b.p. 21 109, and tetrahydro-eucarveol C 10 H 19 OH, b.p. 220, which, on 
 oxidation, turn into the corresponding ketones. 
 
 Dihydro-eucarvone C 10 H 16 O, b.p. 14 87 (B. 28, 646), and tetra- 
 hydro-eucarvone C 1(? H 18 O, b.p. 13 9i-93 (B. 31, 2071). The latter, 
 with chromic acid, gives a ketonic acid C 10 H 18 O 3 , from which potassium 
 hypobromite forms a j3/3-dimethyl-pimelinic acid, indicating the exist- 
 ence of a chain of seven members. 
 
PINANE GROUP 515 
 
 On prolonged heating eucarvone turns into carvacrol ; PC1 5 pro- 
 duces 2-chloro-cymol. The unsaturated diamine, obtained from the 
 oxamino-oxime of eucarvone by reduction, yields p-cymol by the 
 distillation of its phosphate. In this case, we must assume the inter- 
 mediate formation of a cyclo-heptatriene derivative, which transposes 
 into the more stable benzene derivative. 
 
 Dihydro-eucarvylamine C 10 H 17 NH 2 , b.p. 4 p 117, from eucarvoxime ; 
 its chlorohydrate yields euterpene on heating (A. 305, 239). Tetra- 
 hydro-eucarvylamine C 10 H 19 NH 2 , b.p. 210 (A. 339, 115). 
 
 III. PINANE GROUP. 
 
 Hydrocarbons. Pinene. Pinene is extremely frequent among the 
 ethereal oils and is the chief ingredient of the turpentine oils obtained 
 from the different varieties of pine. It also occurs in many other 
 ethereal oils eucalyptus, juniper-berry, sage, etc. 
 
 Turpentine Oil. Turpentine, the resinous juice exuding from 
 various Coniferae, consists of a solution of resins in turpentine oil 
 which distils with steam, while the resin (colophony) remains behind. 
 Turpentine oil is a colourless liquid, boiling at i58-i6o, with specific 
 gravity of o*856-o-87. Its peculiar odour is due to the aldehyde- 
 like oxidation products (B. 29, R. 871) produced by the action of 
 sunlight. 
 
 It is almost insoluble in water, but is miscible with absolute alcohol 
 and ether. It dissolves phosphorus and rubber, and serves for the 
 preparation of varnishes and oil-colours. 
 
 The turpentine oils, according to their origin, are distinguished by 
 different rotatory powers. 
 
 The American, Algerian, and Greek turpentine oils contain chiefly 
 d-pinene, the French and Spanish oils 1-pinene. Besides these, dextro- 
 and laevo-rotatory pinenes are found in various ethereal oils, such as 
 eucalyptus oil, hawthorn (?) oil, sage oil, etc. 
 
 In most cases pinene is accompanied by small quantities of a closely 
 related terpene of higher boiling-point, which, with HC1, gives the same 
 chlorohydrate, but is distinctly different from it in its oxidation pro- 
 ducts. This is especially the case in the oils of turpentine, and the 
 related body is distinguished as j3-pinene from the ordinary or 
 a-pinene. 
 
 CH=C(CH 3 ) CH 
 
 [d+1]- a- Pinene (CHg^c , b.p. 155, Doo 0-858, n D = 
 
 CH 2 -- CH CH, 
 1.46553 (21). 
 
 d-a-Pinene is obtained by fractional distillation of American tur- 
 pentine oil, while 1-a-pinene is obtained from French turpentine oil, 
 but not chemically pure. For obtaining pure a-pinene it is converted 
 into the easily purified nitroso-chloride (/J-pinene gives no addition 
 product with nitroso-chloride), and is thus liberated with the help of 
 aniline, or by boiling with sodium acetate and glacial acetic acid. It 
 is thus obtained pure, but always inactive. Artificially, 1-a-pinene has 
 been obtained by heating nopinol-acetic acid, and d-a-pinene by the 
 
516 ORGANIC CHEMISTRY 
 
 dry distillation of methyl-xanthogenate from pino-campheol (A. 368, 
 i ; C. 1908, I. 1179). 
 
 Pinene has one double link. It combines with 2C1 or 2Br to form 
 compounds which on heating disintegrate into hydrogen haloid and 
 p-cymol. By the action of moist hydrogen haloids, pinene is con- 
 verted into dipentene dihydro-haloids, while with perfectly dry 
 hydrogen haloids in the cold, monohalogen hydrates are obtained. 
 These, however, like the halogen addition products, no longer contain 
 the pinene ring, the hydrogen haloid having produced a complete 
 change in the ring system, giving rise to borneol derivatives. Thus 
 the pinenic hydro-haloids are identical with the bornyl haloids. In the 
 same way the treatment of pinene with organic acids, such as oxalic 
 acid, salicylic acid, trichloracetic acid, etc., produces esters of borneol, 
 or of the stereo-isomeric iso-borneol. This easy transition of pinene 
 into borneol, and iso-borneol, has been industrially utilised for the 
 artificial production of camphor from oil of turpentine. The action 
 of dilute nitric or sulphuric acid upon pinene produces terpine 
 hydrate, while, with sulphuric acid and glacial acetic acid, or benzol- 
 sulphonic acid (C. 1909, II. 25), the primary hydration product 
 a-terpineol can be isolated. On heating to 25O-270 pinene is con- 
 verted into dipentene. 
 
 The oxidation products of pinene have been examined in some 
 detail. In air, oil of turpentine gradually absorbs oxygen with the 
 formation of peroxides (B. 31, 3046), and resinifies with formation of 
 certain quantities of formic acid, acetic acid, and cymol. On the 
 formation of pinol hydrate from pinene in air and sunlight, see below. 
 Strong oxidising agents, such as nitric acid, produce terebinic acid, 
 p-toluic acid, terephthalic acid, etc. Chromic acid mixture produces 
 terpenylic acid as a main product. 
 
 Oxidation with mercuric acetate produces a racemic sobrerol, which 
 is further oxidised to oxy-dih}/dro-carvone or carvone hydrate. From 
 the latter, on heating with oxalic acid, water is eliminated, with forma- 
 tion of carvone and carvacrol, and, on further oxidation with potassium 
 permanganate, terpenylic acid (C. 1909, I. 1561). 
 
 By careful oxidation of pinene with potassium permanganate, we 
 first obtain a-pinene-glycol C 10 H 16 (OH) 21 , b.p. 14 146 (B. 27, 2270), and 
 then a keto-monocarboxylic acid called pinonic acid C 10 H 16 O 3 , m.p. 
 70 (active) and m.p. 104 (inactive), b.p. 15 187 (C. 1909, II. 2158). 
 There are also small quantities of a ketone-dicarboxylic acid, pinoyl- 
 formic acid C 10 H 14 O 5 , m.p. 79. The pinene ozonide, obtained by the 
 action of ozone upon pinene, also yields pinonic acid in the decom- 
 position with water (B. 40, 138). 
 
 On oxidising the very unstable pinonic acid with bromine, or 
 alkali, or with dilute nitrous acid, we obtain the stable pinic acid 
 C 9 H 14 O 4 , m.p. 102, and from this, through a-bromo- and a-oxy-pinic 
 acid, and oxidation of the latter, we obtain nor-pinic acid C 8 H 12 O 4 , 
 m.p. 174. The two latter very stable acids probably contain a tetra- 
 methylene ring. 
 
 Baeyer, therefore, in agreement with Wagner, assumes for pinonic 
 acid and pinene the presence of a 4-member so-called piceane ring 
 (B. 29, 2776) . The course of the oxidation is illustrated in the following 
 scheme : 
 
PINANE GROUP 517 
 
 CO 2 H CH 3 CH 3 
 
 OC C OC HO a C H0 2 C 
 
 \ S'\ \ \ \ 
 
 H0 2 C H,C /CH HC H.C/CH HO 2 C Hj g CH HO 2 C HsC CH H ,c CH 
 
 - ' / / 
 
 c- ' c 
 
 [CH; ICH, " ICH, 
 
 H 2 C CH 2 H 2 C CH 2 H 2 C 
 
 \ / \ / \ 
 
 c I __ 
 
 |CH 
 
 CH 2 H 2 C CH 2 HO 8 C 
 
 CH, 
 
 CH 2 
 
 CH CH CH CH CH 
 
 Pinoyl-formic acid a-Pinene Pinonic acid Pinic acid Nor-pinic acid. 
 
 The decomposition of pinonic acid and pinoyl-formic acid has also 
 been accomplished in other ways. 
 
 (i) By means of chromic acid, keto-iso-eamphoric acid has been 
 obtained from pinonic acid, and also by oxidation of campholinic acid. 
 The keto-iso-camphoric acid can be disintegrated into iso-camphoronic 
 acid CO 2 HC(CH 3 ) 2 CH(CH 2 CO 2 H) 2 (synthesis, C. 1901, I. 221), and 
 further to dimethyl-triearballylie acid CpOHC(CH 3 ) 2 CH(COOH)CH 2 
 COOH. The constitution of the latter acid is proved by the splitting 
 up of the corresponding oxy-acid (B. 30, 1959) on fusing with potash in 
 dimethyl-succinic acid and oxalic acid. The peculiar formation of 
 keto-iso-camphoric acid from pinonic acid can, according to modern 
 ideas (cp. B. 32, 2080), be interpreted in a sense that the 4-member 
 piceane ring of pinonic acid takes up water and is converted into the 
 5-member camphoceane ring : 
 
 ;HCH,CO,H rnH 
 
 CH.COCH.CtCH.), '\C(CH,)(OH).C(CH,) 2 C * H \CH,CO.C(CH,), 
 
 Pinonic acid a-Dioxy-dihydro-campholenic acid Keto-iso-camphoric acid. 
 
 (2) On heating with acids, pinonic acid undergoes an intermediate 
 hydrolytic splitting, and then a transposition into homo-terpenylic- 
 
 f 
 
 methyl-ketone [metho-ethyl-heptanonolide] * z ''; , which 
 
 CH 2 .u/H 2 .CO.Cri3 
 
 we have learnt to regard as a disintegration product of terpineol. 
 Similarly, pinoyl-formic acid is transposed into homc-terpinoyl-formie 
 
 acid (CH3)aC CH ^^CC^COOH' These trans P si tion products on further 
 oxidation yield : 
 
 Terebinicacid (Cl/caCH,.COO 
 
 COUri 
 
 Terebinic acid C 7 H 10 O4, melting at 175, was first obtained by 
 oxidising turpentine oil with nitric acid ; it is also produced in the 
 oxidation of terpenylic acid with potassium permanganate, or of iso- 
 propyl-succinic acid with chromic acid. Synthetically, it is prepared by 
 the condensation of acetone and bromo-succinic ester with zinc-copper, 
 or by the action of CH 3 MgI upon aceto-succinic ester (C. 1907, 1. 1202). 
 See also Teraconic acid (B. 29, 933 ; C. 1898, I. 558 ; 1899, I. 1158) 
 It behaves analogously to the paraconic acids. When heated it loses 
 
5i8 ORGANIC CHEMISTRY 
 
 carbon dioxide and becomes pyro-terebinic acid (CH 3 ) 2 C : CHCH 2 COOH, 
 together with iso-capro-lactone and teraconic acid (CH 3 ) 2 C : C(COOH) 
 CH 2 .COOH, from which it can be re-formed by digestion with mineral 
 acids. Baryta water converts terebinic acid into the crystallising 
 barium salt of diaterebinic acid or oxy-iso-propyl-succinic acid. 
 
 By oxidation with HNO 3 , terebinic acid is turned into diearboxy- 
 
 valero-lactonic acid COOH.C(CH 3 )CH(COOH)CH 2 Co6 (B. 32, 3662). 
 See the formation of terebinic acid from caronic acid. 
 
 Terpenylic acid C 8 H 12 O 4 melts at 90 when anhydrous. It is 
 obtained by oxidising turpentine oil with a chromic acid mixture, and 
 homo-terpenylic acid with nitric acid (B. 29, 2789). 
 
 Synthetically it has been obtained by the action of CH 3 MgI upon 
 jS-acetyl-glutaric ester (C. 1907, I. 1202). 
 
 Upon distillation it yields teraerylic acid (CH 3 ) 2 C : CH(CH 3 )CH 2 . 
 COOH. Terpenylic acid, by reduction, becomes fi-iso-propyl-glutaric 
 acid (see B. 29, 920, 2621). 
 
 Homo-terpenylic acid C 9 H 14 O 4 , melting at 102, results when homo- 
 terpenyl-formic acid is oxidised with nitric acid or with lead oxide 
 (B. 29, 1916). It is synthesised by means of CH 3 MgI and j9-acetyl- 
 adipinic ester (C. 1907, I. 1202). 
 
 The oxidation of pinene to pinonic acid and the hydrolytic re- 
 arrangement of the latter to homo-terpenylic methyl-ketone is certainly 
 to be regarded as the reverse of the processes which take place in the 
 hydrolytic rearrangement of pinene into terpin hydrate, terpineol, and 
 the oxidising decomposition of the latter into homo-terpenylic methyl- 
 ketone (above). 
 
 d-Pinene hydrochloride, smelling of camphor, and therefore formerly 
 called artificial camphor, C 10 H 17 C1, melting at 125 and boiling at 208, 
 is formed on conducting dry hydrochloric acid gas into well-cooled 
 pinene. It is a white crystalline mass, with an odour like that of 
 camphor. The hydrochloride from d-pinene is optically inactive, while 
 the 1-pinene hydrochloride is laevo-rotatory, [a] = 30. Pinene 
 hydrobromide melts at 40 (A. 227, 282). 
 
 Pinene hydro-iodide C 10 H 17 I, b.p. 15 119. The pinene hydro- 
 haloids are identical with the bornyl haloids. This follows from the 
 fact that the Mg compound C 10 H 17 MgCl, obtained by the action of 
 Mg upon pinene chlorohydrate in ether solution, turns into camphane 
 by decomposition with water, and into borneol by the action of 
 oxygen (B. 39, 1127). During the action of the halogen hydrides upon 
 pinene there is, therefore, a " sliding " of the dimethyl-methylene 
 bridge, from the m-position into the p-position. By a quite analogous 
 displacement of the methylene group of the piceane ring, we obtain 
 the derivatives of fenchyl alcohol. This explains the secondary 
 formation of fenchyl chloride in the action of HC1 upon pinene. The 
 elimination of HC1 from pinene chlorohydrate, which is attended by 
 much difficulty, produces camphene. This transition also is the result 
 of a far-reaching transposition. Hypochlorous acid attaches itself to 
 pinene with dissolution of the double linking, and of the four-membered 
 piceane ring. The action of alkalies upon the resulting dichloro- 
 hydrins C 10 H 18 O 2 C1 2 has been made to produce pinol oxide, sobrery- 
 thrite, pinol-chlorohydrin, and other bodies (B. 32, 2064). 
 
PINANE GROUP 519 
 
 Pinene dibromide C 10 H 16 Br 2 , m.p. 170, by the action of bromine 
 upon pinene, in carbon tetrachloride (A. 264, i). Like pinene chloro- 
 hydrate, it probably also belongs to the camphor type, being reduced 
 to camphane by Na and alcohol (B. 33, 3423). On treatment with 
 zinc dust it yields a terpene, isomeric with pinene and camphene, 
 m.p. 67, b.p. 153, containing apparently no double link, a so-called 
 tricyclene. 
 
 Pinene nitroso-chloride, melting at 115, is obtained by means of 
 nitrosyl chloride, or amyl nitrite, glacial acetic acid, and hydrochloric 
 acid. Hydrogen chloride in ether, when allowed to stand in contact 
 with it, produces, just like limonene nitroso-chloride, hydrochloro- 
 carvoxime (B. 29, 12). With KCN it turns into nitroso-cyanide, m.p. 
 171 (C. 1902, II. 363). Pinene nitroso-bromide, m.p. 92. While 
 aromatic bases, like aniline and methyl-aniline, reject NOC1, and re- 
 generate pinene, it turns into nitrolamines with aliphatic bases : 
 pinene-nitrolamine, m.p. 137 (C. 1907, I. 1040) ; pinene-nitrol- 
 piperidide, m.p. 119. By the action of sodium alcoholate, it splits 
 off HC1 and forms nitroso-pinene C 10 H 14 : NOH, m.p. 131, which is 
 regarded as the oxime of an unsaturated ketone, carvo-pinone, into 
 which it turns, on heating with aqueous oxalic acid. By reduction 
 with zinc dust and glacial acetic acid, it forms pinylamine C ]0 H 15 NH 2 ; 
 a ketone isomeric with camphor, pino-camphone, is also formed. 
 
 j8-Pinene, nopinene (formula below), b.p. i62-i63, D 22 0-866, 
 n D =1-4724, is found in small quantities beside a-pinene in turpentine 
 oils, especially American, in a laevo-rotatory form. It has also been 
 traced in lemon oil, coriander oil, hyssop oil, and the oil of Siberian 
 pine needles (C. 1909, II. 2158). It has been synthesised from nopinol- 
 acetic acid by heating with acetic anhydride (A. 363, 9). It unites 
 with HC1 to form a mixture of bornyl chloride and dipentene dichloro- 
 hydrate ; with nitrosyl chloride it does not, like a-pinene, form an 
 addition product. But it unites with nitrous acid to a very unstable 
 pseudo-nitrosite, which, on treatment with ammonia, or by distilla- 
 tion with steam (A. 346, 243), turns into nitro-terebentene, nitro-j3- 
 pinene C 10 H 15 NO 2 , with rejection of hyponitrous acid. The latter, on 
 reduction with Sn and HC1, yields amido-terebentene C 1? H 15 NH 2 , b.p. 12 
 95, from which, with nitrous acid, an alcohol is obtained, which, on 
 oxidation with chromic acid, turns into tetrahydro-cumin-aldehyde, or 
 cuminic acid (A. 346, 246; cp. Phellandrene) . 
 
 On oxidation with KMnO 4 , we obtain from the j3-pinene-glyeol 
 C 10 H 16 (OH) 2 , m.p. 76, which is first formed, nopinic acid CjoH^Og, 
 m.p. 126, an a-oxy-acid characterised by its sparingly soluble sodium 
 salt, and a ketone, nopinone C 9 H 14 O (A. 356, 227 ; 368, 9). 
 
 CH 2 CH 2 OH COOH 
 
 COH CO 
 
 H 2 C HsC/ CH 
 
 H 2 C CH 2 H 2 C CH, 
 
 CH CH 
 
 /?-Pinene-glycol Nopinic acid Nopinone. 
 
520 ORGANIC CHEMISTRY 
 
 Alcohols. Univalent Alcohols. Pino - carveol C 10 H 15 OH, b.p. 
 2i5-2i8 > probably contained in the oil of Eucalyptus globulus 
 (A. 346, 277). It is made artificially by the action of nitrous acid upon 
 pinylamine (A. 346, 221). On oxidation with chromic acid it yields 
 pino-carvone, and on heating with potassium bisulphate, or dilute 
 sulphuric acid, p-cymol. 
 
 CH=C(CH 2 OH).CH 
 
 Myrtenol 
 
 (CH 3 ) 2 C 
 
 , b.p. 223, D 20 0-9763, [a] D +45 45', 
 
 CH ? CH CH 2 
 
 in the form of its acetate, the chief constituent of myrtle oil. The 
 myrtenyl chloride C 10 H 15 C1, formed by the action of PC1 5 , yields, on 
 reduction with Na and alcohol, d-a-pinene. On oxidation with 
 chromic acid the corresponding aldehyde is obtained, myrtenal 
 C 10 H 14 O, b.p. 1( ) 87-90. By means of KMnO 4 myrtenol can be re- 
 duced to d-pinic acid (B. 40, 1363). 
 
 Methyl-nopinol, pinene hydrate C 9 H 14 /*? , m.p. 59, b.p. 205, 
 
 XL/WS 
 
 smells of camphor, and is obtained from nopinone and CH 3 MgI. By 
 the action of dilute sulphuric acid, it passes into optically active 
 a-terpineol (A. 360, 88) and terpin hydrate. With glacial acetic acid 
 and HC1, it turns into dipentene-dihalogenide. With PC1 5 it gives a 
 chloride, b.p. 12 97-io5, which must be regarded as the true chloro- 
 hydrate of pinene (A. 356, 239). Ethyl- and propyl-nopinol, see A. 
 360, 91. 
 
 Pino-campheol C 10 H 17 OH, b.p. 218, by reduction of pino-camphone. 
 Its methyl-xanthogenate, m.p. 61, yields, on heating, a-pinene (C. 
 1908, I. 1179). 
 
 Polyvalent Alcohols. These no longer contain the carbon skeleton 
 of pinene. 
 
 Pinol hydrate, sobrerol C 10 H 16 (OH) 2 , is known in three modifications. 
 d-Pinol hydrate, melting at 150, [a] D = + 150, and 1-pinol hydrate, 
 melting at 150, [a] D = 150, are produced when dextro- and laevo- 
 turpentine oil are oxidised in the air on exposure to sunlight, [d-fl]- 
 Pinol hydrate results on treating pinol with hydrobromic acid and 
 alkali, as well as upon mixing equimolecular quantities of d- and 1-pinol 
 hydrates. Pinol hydrate is an unsaturated compound. Bromine 
 converts it into a dibromide, melting at 131. Potassium perman- 
 ganate changes it to a tetra-acid alcohol, sobrerythrite C 10 H 16 (OH) 4 , 
 melting at 156 (B. 29, 1195, R. 587). 
 
 An isomeric sobrerythrite, m.p. 194, is obtained from the result 
 of the action of C1OH upon pinene (B. 32, 2069). 
 
 Pinol, [d+l]-sobrerone C 10 H 16 O, boiling at 183, with sp. gr. 0-953 
 (20), n D =i'46949, is optically inactive. It is formed when the three 
 pinol hydrates are treated with dilute sulphuric acid, and from the 
 dibromide of terpineol by the splitting off of 2HBr. It is as indifferent 
 as cineol towards hydroxylamine, phenyl-hydrazin, and acid chlorides. 
 This, as well as its formation from terpineol dibromide, is represented 
 in the following formula : 
 
 CH 3 .CBr^HBr.CH,\ CH C(OH)(CH3)2 > CU 3 C(^^pcil 
 
 Terpineol dibromide Pinol. 
 
PINANE GROUP 521 
 
 Pinol hydrate is a hydrate corresponding to this oxide, an oxy- 
 terpineol, which results from pinene by the rupture of the pinene 
 ring. 
 
 Pinol dibromide C 10 H 16 Br 2 O, melting at 94 and boiling at 143 
 (u mm.), is converted by sodium or alcoholic potash into pinol. 
 
 With HBr it gives pinol tribromide C 10 H 17 Br 3 O. The latter splits 
 oft HBr, and forms an isomeric iso-pinol dibromide which, with 
 potash, easily forms i-carvone and, on reduction, a new ketone, 
 pinolone C 10 H 16 O (A. 306, 267). 
 
 Formic acid reduces it to cymene (A. 268, 225). Pinol nitroso- 
 chloride C 10 H 16 O.NOC1, melting at 103, forms nitrolamines with bases. 
 Pinol-glyeol C 10 H 16 O(OH) 2 , melting at 125, is obtained from pinol 
 dibromide with silver oxide or lead hydroxide, or from its diacetate, 
 melting at 97 (A. 268, 223). It is also formed from pinol oxide 
 C 10 H 1? O 2 , b.p. 207, with dilute acids. The latter is obtained from 
 the pinene-dichloro-hydrins with alkalies, and should be regarded as 
 the dianhydride of sobrerythrite. A stereo-isomeric pinol-glycol is 
 formed by the oxidation of pinol with KMnO 4 (B. 28, 2710 ; C. 1898, 
 
 II- 543)- 
 
 Pinol-chloro-hydrins C 10 H 16 OC1 (OH), m.p. 131, are also obtained 
 from the pinene-dichloro-hydrins, the dextro-form resulting from 
 1-pinene and the laevo-form from d-pinene (B. 32, 2070). 
 
 Bases. Pinylamine C 10 H 15 NH 2 , b.p. 207, D 0-943, by reduction 
 of nitroso-pinene (A. 268, 197). By the action of nitrous acid it 
 turns into pino-carveol. Amido-terebentene (see above). 
 
 Dihydrp-pinylamine, pino-camphylamine C 10 H 17 NH 2 , b.p. 199, 
 by reduction of nitroso-pinene with Na and amyl alcohol (C. 1907, 
 I. 252). 
 
 CO C(CH 3 )=C 
 
 Ketones. Carvo-pinone (CH 3 ) 8 c x (?), b.p. 12 95 (A. 346, 
 
 CH 2 CH CH 2 
 
 231), is formed by heating nitroso-pinene, which may be regarded 
 as carvo-pinone-oxime, with aqueous oxalic acid. Hydroxylamine 
 regenerates nitroso-pinenes. Acids easily isomerise it to carvone. It 
 is isomeric with 
 
 Pino-carvone C 10 H 16 0, b.p. 12 95, the oxidation product of pino- 
 carveol. KMn0 4 decomposes it to form pinic acid (A. 346, 222). 
 CO CH(CH 3 )-CH 
 
 Pino-camphone (CH^c/ , b.p. 12 87, D 0-959, is formed 
 
 CH a CH-CH 2 
 
 beside pinylamine in the reduction of nitroso-pinene with zinc and 
 glacial acetic acid. 1-Pino-camphone has been found in the oil of 
 Hyssopus officinalis (C. 1909, II. 2158). By oxidation with KMnO 4 
 it forms pinonic acid and a dicarboxylic acid isomeric with camphoric 
 acid, C^A, m.p. 186 (A. 346, 235). 
 
 Nopinone (constitution, see above), b.p. 209, D 20 0-981, an oxidation 
 product of ^-pinene. On heating with dilute H 2 SO 4 , it is isomerised 
 into A 2 -iso-propyl-cyclo-hexenone (A. 356, 227). The nopinol-acetic 
 acid C 9 H 14 (OH)CH 2 COOH, m.p. 84, obtained by condensation with 
 bromo-acetic ester and zinc (A. 363, 7), forms the fundamental 
 
522 ORGANIC CHEMISTRY 
 
 material for the partial synthesis of a- and j8-pinene as well as 
 fenchene (q.v.). 
 
 IV. CAMPHANE GROUP. 
 
 'CH a 
 
 CH 2 CH < 
 
 i. Hydrocarbons. Camphene 
 
 CH, 
 
 1 3 
 
 , m.p. 
 
 o V^.H.2 v-' v^-JT.2 
 
 b.p. i59-i6i, D 54 0-842, n D = 1-45514 (54), is the only known natural 
 solid terpene. It is known in a d-, 1-, and an optically inactive modi- 
 fication ; these are similar in chemical deportment. Camphene has 
 been found, by a rearrangement, in iso-borneol, in the oil from Andro- 
 pogon nardus, and in camphor oil (B. 27, R. 163). It is obtained (i) 
 from borneol by the action of potassium bisulphate at 200 ; (2) by the 
 action of ZnCl 2 or dilute sulphuric acid upon iso-borneol ; (3) when 
 sodium acetate and glacial acetic acid at 200 act upon pinene hydro- 
 chloride ; and (4) on digesting bornyl chloride with aniline, pyridin, 
 alkaline phenolates, etc. The so-called camphene hydrate, and 
 synthetic methyl-camphenilol, turn into camphene with special ease, 
 eliminating water. 
 
 Camphene only contains one double linking. Camphene and bromine 
 in ether produce : 
 
 Camphene dibromide C 10 H 16 Br 2 , melting at 89, together with 
 liquid bromo-camphene C 10 H 15 Br (B. 29, 544, 697, 900). 
 
 Camphene hydrochloride C 10 H 17 C1, melting at i49-i5i, is produced 
 when HC1 is conducted into an alcoholic camphene solution. It is 
 identical with the iso-bornyl chloride obtained from iso-borneol, and 
 probably stereo-isomeric with pinene chlorohydrate, since both 
 chlorides turn into the same camphene, on reduction with Na and 
 alcohol, or by decomposition of their Mg compound with water. From 
 pinene chlorohydrate, camphene chlorohydrate is specially dis- 
 tinguished by the greater ease with which it passes into camphene, 
 under the influence of dehydrating agents. Camphene, treated with 
 glacial acetic acid and concentrated sulphuric acid, yields iso-borneol 
 acetate. The action of fuming nitric acid upon a chloroform solution 
 of camphene leads to an additive product C 10 H 16 (HNO 3 ), b.p. 10 
 110, which regenerates camphene with alcoholic potash (C. 1900, 
 II. 261). 
 
 Camphenile nitrite, nitro-camphene C 8 H 14 > C : CHNO 2 , m.p. 66, 
 b.p. 12 147, is found among the oxidation products of camphene 
 volatilising in steam under the action of dilute nitric acid. It is also 
 produced by the action of nitrous acid upon camphene (B. 32, 1498), 
 probably by splitting off hypo-nitrous acid from the very unstable 
 pseudo-nitrosite formed at first. This, on reduction, yields cam- 
 phenilane-aldehyde, and, by oxidation with KMnO 4 or the action 
 of alcoholic potash, camphenilone ; while, with concentrated H 2 SO 4 , 
 it yields the completely saturated tricyelene-carboxylic acid C 10 H 14 O 2 , 
 m.p. 148, which is indifferent to KMnO 4 (B. 41, 2747; Ch. Ztg. 
 34, 65). 
 
 On oxidising camphene with KMnO 4 (A. 340, 17), camphene-glycol 
 C 10 H 16 (OH) 2 , m.p. 200, is first formed, m.p. 200 ; and this, treated 
 
CAMPHANE GROUP 523 
 
 with dilute H 2 SO 4 , splits off water and turns into camphenilane-alde- 
 hyde C 10 H 16 O, melting at 70 and boiling at 96 (14 mm.). The 
 oxidation of this aldehyde gives rise to two isomeric camphenilanic 
 acids C 10 H 16 O 2 , melting at 65 and 118, which can be changed 
 through the corresponding a-bromo-acid into oxy-camphenilanic acid, 
 camphenilol acid, C 10 H 16 O 3 , melting at 171. This latter acid is 
 also formed when camphene is oxidised with potassium perman- 
 ganate. Its further oxidation causes the elimination of carbon dioxide 
 and the formation of a ketone, camphenilone C 10 H 14 O, melting at 
 43 and boiling at 81 (12 mm.). This is the lower ring-homologue 
 of camphor ; it resembles the latter in odour and in chemical 
 behaviour. By the oxidation of sodium amide, camphenilone is 
 broken up to the amide of 2-iso-propyl-cyclo-pentane-carboxylic 
 acid (B. 39, 2580), which has been disintegrated into 2-iso-propyl- 
 cyclo-pentanone (C. 1908, I. 1271), and has, on the other hand, 
 been obtained synthetically from j8-iso-propyl-adipinic acid (C. 1909, 
 
 I. 443). 
 
 The ozonide produced on treating camphene with ozone, on de- 
 composition with water, or glacial acetic acid, yields camphenilone and 
 the lactone of S-oxy-camphenilonic acid (B. 43, 1432) with splitting of 
 the camphene ring. This has also been obtained synthetically by 
 the action of methyl-magnesium iodide upon the anhydride of cyclo- 
 pentane-i, 3-dicarboxylic acid (B. 42, 898). These various trans- 
 formations are easily understood on the basis of G. Wagner's camphene 
 formula : 
 
 CH CH CH CH 
 
 H^fX 3 
 
 _^ I rw i xc1 3 
 
 | CH 2 N ' n a -> | CH 2 ! -> CH 2 | '-"-* I CH 2 
 
 H 2 C | C=CH 2 H 2 C i C(OH)CH 2 OH H,C I C(OH)CO 2 H H 2 C CO 
 
 *| CH 3 ^ CH ' 
 
 CH CH CH CH 
 
 Camphene Camphene-glycol a-Oxy-camphenilanic acid Camphenilone. 
 
 CH i | i 
 
 v //-TT CH CH Cri 
 
 H,C C<5 
 
 i \v_/rl' 
 
 " n 2 v-, \_/\ ^TT Jn^ I v^\ ^TT n.tf^ \ 
 
 I p-tr i ^^A^-3 i ptr i ^*^ i r*ij 
 
 I ^n 2 1 | *^n t i '^ ri _ 
 
 CO 2 H 
 CO 
 
 CH CH CH 
 
 :H 
 
 ^-Oxy-camphenilone Camphenilane- Camphenilanic acid Iso-propyl-cyclo- 
 
 acid lactone aldehyde pentane-carboxylic 
 
 acid. 
 
 On oxidising the artificial and natural camphenes with KMnO 4 
 (but not with ozone) we obtain, besides the compound already men- 
 tioned, considerable quantities of a dicarboxylic acid, isomeric with 
 camphene-camphoric acid C 10 H 16 O 4 , m.p. 136 (inactive), 144 (active) 
 (A. 375, 336). Its genesis from the above camphene formula can 
 hardly be imagined to take place without the supposition of considerable 
 atomic displacement. It yields no anhydride, and no cyclic-ketone, 
 in the distillation of its calcium salt. Its constitution, and its connec- 
 
524 ORGANIC CHEMISTRY 
 
 tion with the oxidation products of camphene, are not yet clear (A. 375, 
 336). It is possible that it owes its origin to a hydrocarbon isomeric 
 with the above camphene, which would indicate that camphene is a 
 mixture of two isomeric terpenes (see also Tricyclene, below). But 
 this can hardly be made to agree with the almost quantitative 
 conversion of camphene into iso-borneol (see also A. 382, 265 ; 
 383, i). 
 
 A primary transposition is, no doubt, the cause of the production 
 of the tribasic carboxyl-apo-camphoric acid, camphoric acid C 7 H n 
 (COOH) 3 , m.p. 196, in the oxidation of camphene with dilute 
 nitric acid. With chromyl chloride in CS 2 solution, camphene yields 
 an additive compound, C 10 H 16 .2CrO 2 Cl 2 , which is decomposed by 
 water with formation of a camphenilane-aldehyde. In the animal 
 body camphene is oxidised to camphenilane-aldehyde (C. 1903, 
 I. 594). Oxidation with chromic acid converts camphene into 
 camphor. 
 
 The above camphene formula therefore indicates that the pre- 
 paration of camphene from the chlorohydrate of pinene or camphene, 
 or from borneol and iso-borneol, is accompanied by a peculiar atomic 
 displacement, which is reversed by the attachment of halogen hydride 
 and other acids. This transposition involves the conversion of a 
 five-membered ring into a six-membered ring, as shown in the following 
 diagram : 
 
 CH 2 CH CH 2 
 
 ! 8 I I 
 
 | CH 3 CCH 3 1 I CH 3 .C.CH 3 | or 
 
 I 
 
 CH 2 C CHC1 CH 2 CH CH 2 CH C=CH 2 
 
 2 I | 6 2 iQ """ 6 2 6l7 
 
 7CH 3 
 
 7CH 2 
 
 It is closely related to the atomic displacement occurring in the con- 
 version of pinacolin alcohol or its chloride into tetramethyl-ethylene 
 (Vol. I.). 
 
 Under special conditions it is possible to avoid the atomic dis- 
 placement occurring during the elimination of water from borneol, 
 or the elimination of halogen hydride from bornyl haloids, and 
 thus to attain the hydrocarbon forming the foundation of these 
 compounds : 
 
 CH 2 CH CH 
 
 Bornylene 
 
 CH 3 CCH 3 
 
 , m.p. 113, b.p. 146, [a] D 21-69. It is 
 
 CH 2 C CH 
 
 CH 3 
 
 remarkable on account of its great volatility. It is formed from 
 bornyl iodide with concentrated alcoholic potash (C. 1910, I. 2089), or 
 by the dry distillation of bornyl-xanthogenic methyl ester (C. 1905, I. 
 94), besides camphene, which can be separated by conversion into 
 iso-bornyl acetate. It is obtained in a pure state from bornylene- 
 carboxylic acid, by elimination of CO 2 . Bornylene is oxidised by 
 KMnO 4 to camphoric acid. 
 
CAMPHANE GROUP 525 
 
 Camphane, i, 7, 7 - trimethyl - nor - camphane, dihydro - bornylene 
 CH 2 CH CH 2 
 
 /->TT ppTJ' 
 
 , m.p. 153, b.p. 159, sublimes easily. It is formed by 
 CH 2 C CH 2 
 
 CH 3 
 
 the reduction of camphene and pinene hydrochloride or hydro-iodide 
 with sodium and alcohol, or by the decomposition of their magnesium 
 compounds with water, besides small quantities of hydro-dicamphene 
 (C 10 H 17 ) 2 , m.p. 85. As indicated by its symmetrical structure, it is 
 always inactive, whether we start with active or inactive material 
 (B. 39, 1127). On heating with dilute nitric acid, it gives nitro- 
 camphane, m.p. i25-i29. 
 
 Iso - camphane, 5, 5, 6-trimethyl- nor -camphane, dihydro - camphene 
 C 10 H 18 , m.p. 63, is formed by the reduction of camphene with 
 molecular hydrogen in the presence of platinum black (A. 382, 
 265), and by heating iso-borneol with zinc dust to 220 (B. 33, 
 774), in the latter case, no doubt, with intermediate formation of 
 camphene. 
 
 Tricyclene C 10 H 16 , m.p. 68, b.p. 153, is completely saturated. It 
 is contained in small quantities (about 0*4 per cent.) in crude camphene, 
 and remains unchanged during its oxidation with KMnO 4 (A. 340, 17). 
 It is probably identical with the tricyclic hydrocarbon obtained by 
 reduction with zinc dust and alcohol. 
 
 Fenchene C 10 H 16 has not hitherto been traced with certainty in 
 nature. It is formed from the fenchyl chlorides by heating with 
 aniline, quinolin, or alcoholic potash, from iso-fenchyl alcohol by 
 heating with zinc chloride, or by the action of nitrous acid upon 
 fenchylamine. According to the nature of the foundation material, 
 we can obtain dextro- or laevo-rotatory or inactive fenchenes, with 
 boiling-points ranging from 154 to 158, D about 0-87, and n D = 1-4724. 
 Synthetically, a fenchene, either dextro- or laevo-rotatory according to 
 the conditions, has been obtained from nopinol-acetic ester by splitting 
 off water, and by the distillation of the resulting unsaturated acid 
 (A. 363, i). Fenchene combines with bromine to form a crystalline 
 dibromide, m.p. 62 (inactive), 88 (active). With halogen hydride it 
 forms liquid monohalogen hydrates, apparently identical with fenchyl 
 haloids. In the oxidation with permanganate, fenchene behaves very 
 much like camphene. An a-oxy-acid, oxy-fenchene acid C 10 H 16 O 3 , is 
 produced first, and D-l- and L-d-fenchene * yield the two optical 
 antipodes of this acid, m.p. 153, [a] D =63, while the less stable 
 D-d-fenchene yields a feebly dextro-rotatory oxy-fenchenic acid, m.p. 
 138. By oxidation of these acids we obtain ketones C 9 H 14 O, fencho- 
 camphorones, m.p. 110 and 63, lower homologues of camphor closely 
 resembling it and yielding on further oxidation apo-camphoric acid, 
 which is also easily obtained from fenchene with nitric acid (A. 302, 
 371; 315, 273 ; C. 1898, I. 575 ; 1899, II. 1052). 
 
 The gradual disintegration of fenchene is represented by the 
 following series of formulae : 
 
 * The capital letters D- and L- indicate the optical rotation of the d- or 1- 
 fenchones used in the preparation. 
 
526 ORGANIC CHEMISTRY 
 
 C : CH 2 /C(OH)COOH /CO /COOH 
 
 CH 2 C7Hl2 \CH 2 C ' Hl2 \CH 2 C7Hl2 \COOH 
 
 D-1-Fenchene Oxy-fenchenic acid Fencho-camphorone Ape-camphoric 
 
 acid. 
 
 Since the formula of fenchone may be taken as clearly established, 
 we must assume an atomic displacement in its conversion into fenchene 
 corresponding to what happens in the conversion of camphor into 
 camphene. 
 
 Tetrahydro - fenchene C 10 H 20 , b.p. i6o-i65, D 22 = 07945, 
 n D = 1-4370, from fenchone and fenchyl alcohol by heating with HI. 
 
 Dihydro-fencholene C 9 H 18 , see Fencholenic acid. 
 
 In connection with camphene and fenchene, we may mention a 
 hydrocarbon which, from its composition, C 9 H 14 , may be regarded as a 
 lower homologue of terpene. It is found in Indian sandal-wood, in 
 Siberian pine-needle oil, and other pine-needle oils (B. 40, 4918), and 
 
 CH 2 CH C.CH 3 
 
 b.p. 140, D 20 0-863, 
 
 has been termed santene C 9 H 14 = CHj 
 
 CH 2 CH C.CH 3 
 
 n u = i -46658. It is optically inactive. The nitroso-chloride crystallises 
 in blue needles to m.p. 109, which, after a short time, become colourless. 
 Nitrosite, m.p. 125. Monochlorohydrate, m.p. 80. Tribromide 
 C 9 H 13 Br 3 , m.p. 63. During the oxidation with KMnO 4 we obtain, 
 with intermediate formation of santene-glycol C 9 H 14 (OH) 2 , m.p. 197, 
 a diketone C 5 H 8 (COCH 3 ) 2 , b.p. 9 I24-I27, which, on treating with 
 alkaline bromine solution, turns into trans-cyclo-pentane-i, 3-di- 
 carboxylic acid (B. 41, 385). 
 
 A hydrocarbon, probably identical with santene, is formed by boil- 
 ing the teresantaric acid C 1 pH 14 O 2 , m.p. 157, also occurring in sandal- 
 wood, with dilute sulphuric acid. By heating with formic acid, the 
 teresantaric acid turns into an alcohol, the so-called 7r-nor-borneol, 
 santenol, m.p. 98, b.p. 9 88, which is also obtained from santene by 
 hydration with formic acid or glacial acetic acid and sulphuric acid, 
 and whose chloride, m.p. 60, b.p. 10 73, on treatment with alcoholic 
 potash, reverts into santene (B. 40, 4465 ; 41, 125). 
 
 2. Alcohols. A. Monacid Alcohols. Borneo camphor, borneol, 
 
 CH 2 CH CH 2 
 
 icT~T C CTT 
 8 i' , melting at 203 and boiling at 212, occurs 
 
 H 2 C CHOH 
 
 CH 3 
 
 in three modifications in nature. d-Borneol is found in Dryobalanops 
 camphor a, a tree growing in Borneo and Sumatra, also in rosemary oil. 
 I- Borneol and inactive borneol are present in the so-called baldrianic 
 camphor. Many wood-spines contain it in the form of a fatty acid 
 ester, more especially the acetic ester. 
 
 Borneol is very similar to Japan camphor, but has an odour 
 at the same time resembling that of pepper. It sublimes very 
 readily. 
 
 Artificially, it is formed, besides iso-borneol, by the reduction of 
 camphor with sodium and alcohol (A. 230, 225), and by the action of 
 oxygen upon the magnesium compound of pinene chlorohydrate, which 
 
CAMPHANE GROUP 527 
 
 must therefore be regarded as bornyl chloride (B. 39, 1127). In the 
 form of its ester, borneol is obtained by heating pinene with organic acids 
 such as oxalic, benzoic, salicylic, chloro- and nitro-benzoic acids, etc. 
 (C. 1906, II. 1589 ; 1909, 1. 1025). On oxidation, it turns into camphor 
 without change in the direction of optical rotation. On heating with 
 potassium bisulphate or zinc chloride it splits up, though with some 
 difficulty, into water and camphene. 
 
 Methyl ether, b.p. 194. Ethyl ether, b.p. 204 (B. 24, 3713). Acetyl 
 ester, m.p. 29, rhombic hemihedral, b.p. 10 98, n D = 1*46635, [a] D = 
 +38 20', also found in oil from Siberian fir (C. 1903, I. 515). 
 
 The bornyl haloids are identical with the so-called pinene hydro- 
 haloids. Bornyl iodide, on treating with alcoholic potash, yields borny- 
 lene. Bornyl-iso-valerianate, b.p. 255-26o, occurs in baldrian oil, and 
 is used in pharmacy under the name " bornyval." Bornyl salicylate 
 (" salite ") is used as an anti-neuralgic. 
 
 d- and 1-Bornyl-xanthogenie methyl esters C 10 H 16 OCS.SCH 3 yield 
 d- and 1-bornylene on distillation at ordinary pressures. 
 
 Iso-borneol C 10 H 17 OH, m.p. 212, is probably the stereo-isomeric 
 alcohol corresponding to borneol. It is more volatile than borneol, 
 and is formed together with the latter in the reduction of camphor, 
 into which it passes by oxidation with KMnO 4 , ozone, etc., with reversal 
 of its optical rotation (B. 39, 1131). By the action of sodium in xylol 
 or benzine solution, iso-borneol is transformed into borneol (C. 1909, II. 
 25). Iso-bornyl acetate, b.p. 13 107, is formed by heating camphene 
 with glacial acetic acid and 50 per cent. H 2 SO 4 to 5o-6o (German 
 patent 67,255 ; B. 27, R. 102), or by transformation of pinene chloro- 
 hydrate with Zn acetate and glacial acetic acid, in which case the zinc 
 chloride acts catalytically (C. 1907, II. 434). Both reactions are of 
 industrial importance as regards the artificial production of camphor 
 from pinene. Both borneol and iso-borneol are formed by the action 
 of oxygen upon magnesium-camphene chlorohydrate (B. 39, 1135). 
 With dehydrating agents it passes into camphene much more easily 
 than borneol. 
 
 Camphene hydrate C 10 H n O s , m.p. 150, b.p. 205, is formed on 
 digesting camphene chlorohydrate with milk of lime. It smells both 
 of fungus and menthol, and passes easily into camphene, on shaking 
 up with dilute mineral acids, and sometimes on mere distillation 
 (B. 41, 1092 ; A. 383, i). 
 
 Methyl-camphenilol C 10 H 17 OH, m.p. 118, b.p. 205, has been ob- 
 tained by the action of CH 3 MgI upon camphenilone. On heating with 
 glacial acetic acid and H 2 SO 4 it splits off water and easily passes into 
 camphene (A. 340, 58). 
 
 Camphol alcohol C 10 H 18 OH, m.p. 60, b.p. 213, is formed by the 
 reduction of campholic ester with sodium and alcohol (C. 1904, II. 303). 
 It differs from the tertiary alcohol of the same name, b.p. 203, pro- 
 duced by the action of silver nitrite upon campholamine chlorohydrate 
 (B. 27, R. 126). This indicates that, in this case, a change in the ring 
 system has taken place (cp. A. 379, 202). 
 
 Camphel alcohol C 9 H 17 OH, melting at 25 and boiling at 179, re- 
 sults from the interaction of camphelamine hydrochloride and silver 
 nitrite. It is a tertiary alcohol. It readily decomposes into water and 
 the hydrocarbon C 9 H 16 (B. 27, R. 126). 
 
528 ORGANIC CHEMISTRY 
 
 Gamphenilol C 9 H 15 OH, m.p. 84, by reduction of camphenilone 
 with sodium and alcohol (A. 366, 72). 
 
 Fenchyl alcohol C 10 H 17 .OH, melting at 45 and boiling at 201, with 
 specific gravity 0-933, is produced in two modifications : by the re- 
 duction of d- and 1-fenchone. It has a penetrating and very disagree- 
 able odour. L-d-fenchyl alcohol, [a] D =-j-io 36', is obtained from 
 1-fenchone and 1-fenchyl alcohol, [a] D = 10 35', from d-fenchone 
 (A. 284, 331). 
 
 i-Fenchyl alcohol has been found in the yellow pine oil of Pinus 
 palustris. It is also formed, besides other alcohols, in the hydration of 
 /3-pinene (C. 1909, II. 25). On oxidation it yields fenchone besides 
 oxy-dihydro-fencholenic acid (B. 42, 2698), and, on splitting off water, 
 fenchene. 
 
 Fenchyl chlorides C 10 H 17 C1, b.p. 14 84-86, are formed from fenchyl 
 alcohol with PC1 5 or HC1, and from fenchene with chlorine hydride. 
 Fenchyl chlorides, of various origins, show different optical rotatory 
 powers, and are probably mixtures of isomeric (secondary and tertiary ?) 
 chlorides. 1-Fenchyl bromide C 10 H 17 Br, b.p. 14 9o-ioo (/. pr. Ch. 2, 
 62, i). D-1-Fenchyl acetate, b.p. 10 88. 
 
 Iso-fenchyl alcohol, m.p. 62, b.p. 13 98. Like iso-borneol, its 
 acetate is formed from fenchene with acetic-sulphuric acid. While 
 fenchyl alcohol yields fenchone upon oxidation, iso-fenchyl alcohol pro- 
 duces an isomeric ketone, iso-fenchone. 
 
 Iso-fencholene alcohol C 10 H 17 OH, b.p. 218, with specific gravity 
 0-927 (20), n D = 1*476, is produced when alcohol and sodium act upon 
 fencholene amide (A. 284, 337). It is readily attacked by potassium 
 permanganate. When heated with dilute sulphuric acid it changes 
 to fenchenol C 10 H 18 O, b.p. 183, with specific gravity 0-925 (20), 
 n D = 1-46108. This compound, with the exception of the boiling- 
 point, cannot be distinguished from cineol. 
 
 Thio-borneol C 10 H 17 SH, m.p. 63, b.p. 12 95, by the action of sulphur 
 upon bornyl-magnesium chloride, and through transposition of hydro- 
 pinene-sulphinic acid, camphane-sulphinic acid C 10 H 17 SO 2 H, m.p. 64, 
 obtained from bornyl-magnesium chloride and SO 2 . Chromic acid 
 oxidises thio-borneol into bornyl disulphide (C 10 H 17 ) 2 S 2 , m.p. 178, 
 which, on distillation at ordinary pressure, decomposes into thio-borneol 
 and thio-camphor (B. 39, 3503). 
 
 3. Amines have been obtained by the reduction of nitroso-pinenes, 
 oximes, and nitriles, as well as ketones with ammonium formate. 
 
 Bornylamine C 10 H 17 .NH 2 melts at 159 and boils at 199. The 
 formyl compound is produced when camphor is heated with ammonium 
 formate, and the base itself by the reduction of camphor-oxime with 
 alcohol and sodium. 
 
 In the latter reaction two geometrically isomeric optically active 
 bases are obtained : bornyiamine, m.p. 173, [a] D =+45'5; and neo- 
 bornylamine, m.p. 180, [a] D = 31-3 (C. 1898, II. 300). 
 
 Bornylamine possesses an odour like that of camphor and piperidin 
 (A. 269, 347). Heated with acetic anhydride, it splits up at 2oo-2io, 
 forming camphene (A. 269, 347). 
 
 Gamphylamine C 9 H 15 .CH 2 .NH 2 , boiling at i94-i96, is produced 
 when the nitrile of campholenic acid is reduced. The benzoyl com- 
 pound melts at 77 (B. 20, 485 ; 21, 1128). 
 
CAMPHANE GROUP 52$ 
 
 Campholamine C 10 H 19 .NH 2 , and camphelamine C 9 H 17 NH 2 , see 
 Campholic acid. 
 
 Camphenamine C 8 H 14 <(^ H2 , b.p. 200 161, D 20 0-9399, formed from 
 
 chloro - camphenamine with soda, which is obtained from amido- 
 borneol C 10 H 16 (OH)(NH 2 ), the reduction product of amido-camphor 
 (B. 33, 481). With HNO 2 , camphenamine gives a tertiary unsaturated 
 alcohol C 10 H 15 (OH), m.p. 102, the so-called jS-iso-camphor, isomeric 
 with camphor and closely resembling it (A. 313, 59). 
 
 Campnenylamine C ? H 15 .NH 2 , m.p. 91, b.p. 185, by reduction of 
 camphenilone-oxime with Na and alcohol (A. 366, 75). 
 
 Camphane - diamine C 10 H 16 (NH 2 ) 2 , a wax-like mass, b.p. 246, 
 formed by reduction of camphor-dioxime or amido-camphor-oxime 
 (C. 1905, II. 178). 
 
 Fenchylamine and fencholenamine sustain the same relation to each 
 other that we observed in bornylamine and camphylamine. 
 
 Fenchylamine C 10 H ;7 NH 2 , boiling at 195, with specific gravity 
 0-9095 (22), is known in three modifications, produced from the cor- 
 responding fenchones on heating them with ammonium carbonate, or 
 by reducing the fenchone-oximes. D-1-Fenchylamine, [a] D = 24-89, 
 obtained from d-fenchone, yields D-1-fenchene and d-limonene on 
 the action of HN0 2 . The optical rotatory power of a series of deriva- 
 tives has been studied : 
 
 Formyl-, acetyl-, propionyl-, butyryl-fenchylamines, [a] D = 36-56, 
 -46-62, -53-16, 53-11 (A. 276, 317)- 
 
 Fencholenamine CgHjs.CHg.NHjj, boiling at iio-ii5 (21-24 mm.), 
 results from the reduction of the nitrile of fencholenic acid nitrile 
 (A. 263, 138). 
 
 Fenchelylamine CgH 17 NH 2 , b.p. 173, is formed from fenchelyl iso- 
 cyanate C 9 H 17 N : CO, the result of the action of potassium hypo- 
 bromite upon fencholic acid amide. On dry distillation its chloro- 
 hydrate yields apo-fenchene CgH 16 , b.p. 143, D 21 07945 (A. 369, 79 ; 
 C. 1910, II. 875). 
 
 4. Ketones. Various transformation products of the ketones 
 C 10 H 16 O, camphor and fenchene, have been treated in the preceding 
 sections. By reduction they yield borneol and fenchyl alcohol, from 
 which they are conversely again obtained by oxidation. 
 
 Camphor is known in two optically active modifications and one 
 optically inactive modification, while fenchone is known in two opti- 
 cally active forms. 
 
 d-Camphor, common camphor, Japan camphor C 10 H 16 O 2 , melting 
 at 175 and boiling at 204, with [a] D = +44-22 in alcohol (A. 250, 352), 
 is found in the camphor tree (Cinnamomum camphor a}. It is obtained 
 by distillation with steam and sublimation. Artificially, it is made 
 on an industrial scale by changing oil of turpentine (pinene) into borneol 
 or iso-borneol, and oxidising with KMnO 4 , ozone, nitric acid, etc., but 
 the result is mostly inactive. Camphor is also formed by oxidation 
 of camphene with chromic acid. It is a colourless, transparent mass, 
 crystallises from alcohol, and sublimes in shining prisms of specific 
 gravity 0-985. It is very volatile, and is applied therapeutically as 
 well as in the manufacture of celluloid and smokeless powder. Its 
 alcoholic solution is dextro-rotatory. Camphor yields pure cymol if 
 
 VOL. II. 2 M 
 
530 ORGANIC CHEMISTRY 
 
 distilled with P 2 O 5 , and on boiling with iodine forms carvacrol C 10 H 14 O. 
 When boiled with nitric acid it yields different acids, chiefly camphonic 
 and camphoronic acids. Upon reduction it passes into borneol and 
 iso-borneol. 
 
 1- Camphor, matricaria camphor, is contained in the oil of Matri- 
 caria Parthenium. It resembles d-camphor even to the rotatory 
 power [a] D = 44*22. It yields 1-camphoric acid upon oxidation. 
 
 (d-f-1)- Camphor, melting at 178-6, is produced on mixing d- and 
 1-camphors, and by the oxidation of i-borneol and i-camphene with 
 chromic acid (B. 12, 1756). Also by racemising ordinary camphor with 
 A1C1 3 (C. 1899, I. 1243). 
 
 Constitution of Camphor. The camphor formula (i) proposed by 
 Kekule (1873) satisfactorily accounted for the change of camphor into 
 p-cymol and carvacrol. However, the ready anhydride formation of 
 camphoric acid, which had led to a seven-membered ring, could not 
 be brought by it into accord with the known experiences relating to 
 the anhydride formation of aliphatic dicarboxylic acids. The lack of 
 additive power also remained unexplained. The formulae of Kanonni- 
 koff and Bredt explained these relations much better. In them the 
 p-carbon atoms of the hexagon of camphor were brought in direct 
 union. The anhydride formation of camphoric acid, thus made 
 parallel with ethylene-succinic acid, could be understood on the basis 
 of this formula. Baeyer (1893) showed that, as camphoric anhydride 
 melted higher than its hydrate, it probably contained an n-glutaric 
 acid anhydride ring (A. 276, 265). 
 
 Camphoric acid is not the only oxidation product of camphor, for 
 when it is further oxidised camphanic acid and camphoronic acid are 
 produced. In the latter acid J. Bredt recognised a, a, /Mrimethyl- 
 tricarballylic acid, inasmuch as it decomposed, upon the application 
 of heat, into trimethyl-succinic anhydride, iso-butyric acid, carbonic 
 acid, water, and carbon ; whereas, when camphoronic acid, the lactone 
 of oxy-camphoronic acid, obtained from it, is fused with caustic potash, 
 trimethyl-succinic acid and oxalic acid are produced very readily. 
 Bredt concludes from this behaviour that the carbon grouping of cam- 
 phoronic acid, as well as that of trimethyl-succinic acid, must be present 
 in camphanic acid, camphoric acid, and camphor. The formula of 
 Bredt (1893) may be imagined (B. 26, 3047) to have been evolved from 
 that of Kekule by rotating the iso-propyl group about 180, until it lies 
 within the hexagon, and then its middle carbon atom is allowed to 
 unite the two p-carbon atoms of the hexagon by the migration of an 
 H atom and the dissolution of the double union : 
 
 CH,.CHCH 3 CH 3 CHCH 3 CH 3 CHCH 3 
 
 CH C C CH 
 
 H 2 C C 
 Hci I 
 Y 
 
 O H 2 C 
 
 H,C 
 
 H 2 C N CH 2 
 
 !CH 3 .C.CH 3 | 
 CO H 2 C I CO 
 
 Ho H 2 C 
 
 MX \/ 
 
 _ r C C 'C' 
 
 CH 3 CH 3 CH 3 CH 3 
 
 (Kekul6, 1873) (Kanonnikoff, 1883) (Bredt, 1884) (Bredt, 1893). 
 
 The position of the CO group is proved by the conversion of 
 camphor into carvacrol (see above). 
 
CAMPHANE GROUP 531 
 
 The oxidation of camphor (i) to camphoric acid (2), camphanic 
 acid (3), and camphoronic acid (4), as well as the decomposition of the 
 latter into trimethyl-succinic acid (5), also found among the oxidation 
 products of camphor (B. 26, 2337), is represented in the following 
 diagram : 
 
 CH 2 CH CH 2 
 
 (CH 3 ) 2 C 
 CH 2 C CO 
 
 (i) CH 3 (2) CH 3 
 
 C0 2 H C0 2 H C0 2 H 
 
 (CH 3 ) 2 C - _> (CH 3 ) 2 C 
 
 CH 2 C CO 2 H CH CO 2 H 
 
 (4) CH 3 (5) CH 3 
 
 This interpretation is corroborated by the synthesis of camphor, 
 which can be carried out as follows (Komppa, A. 370, 209). 
 
 Oxalic ester and j3-dimethyl-glutaric acid ester are condensed by 
 sodium ethylate to diketo-apo-camphoric acid ester (i) ; by means of 
 methylation with methyl iodide and sodium, in alcoholic solution, 
 this is turned into diketo-camphoric acid ester (2). By means of the 
 intermediate products dioxy-, dehydro-, and bromo-camphoric acid 
 the diketo-camphoric acid may be reduced to a mixture of cis- and 
 trans- [d+1] -camphoric acid (3), which are separated by utilising their 
 different behaviour in forming anhydrides. cis-Camphoric anhydride 
 is reduced to the lactone campholide (4) by means of Na amalgam, 
 and this combines with potassium cyanide to the nitrile of homo- 
 camphoric acid (5). The latter, which can also be prepared from 
 cyano-camphor by saponifkation and splitting, 3/ields camphor (6) on 
 distillation of its calcium salt : 
 
 :OOR CH Z co 2 R 
 
 + C(CH 3 ) 2 --> 
 
 :OOR CH 2 co 2 R 
 :O.CH co 2 H 
 
 C(CH 3 ) 2 > 
 :O.C(CH 3 ).C0 2 H 
 
 (I) ( 
 
 C 
 
 (3) ( 
 
 C 
 
 :O.CH C0 2 R (2) 
 C(CH 3 ) 2 > 
 
 ;O.CH co 2 R 
 :H Z .CH co 2 H ( 4 ) 
 
 C(CH 3 ) 2 -* 
 :H 2 .C(CH 3 ).C0 2 H 
 
 CO 2 CH CO 2 R 
 | C(CH 3 ) 2 
 CO.C(CH 3 ).CO 2 R 
 CH 2 .CH CH 2 
 
 | C(CH 3 ) 2 ;>o 
 
 CH 2 .C(CH 3 ) CO 
 
 :H 2 .CH.CH 2 CN 
 | C(CH 3 ) 2 > 
 :H 2 .C(CH 3 ).COOH 
 
 (5) CH 2 .CH.CH 2 C0 2 (6) 
 | C(CH 3 ) 2 \ Ca __ > 
 CH 2 .C(CH 3 ).CO/ 
 
 CH 2 .CH CH 2 
 C(CH 3 ) 2 i 
 CH 2 .C(CH 3 ).CO. 
 
 Since racemic camphoric acid can be split up into d- and 1-camphoric 
 acids by means of its cinchonidin salt, the above process is also useful 
 for the preparation of optically active camphor. 
 
 On a second method of synthesising camphor, see Perkin and 
 Thorpe, C. 1906, II. 241. 
 
 On the stereo-isomerism of the camphor molecule, see A. 316, 196 
 (also J. Bredt, Uber die racemliche Configuration des Camphers, 
 Leipzig, 1905). 
 
532 ORGANIC CHEMISTRY 
 
 The camphor formula leads to the formulae for borneol, camphene, 
 and numerous other compounds in genetic connection with camphor. 
 The recognition of the connection between camphor and its transforma- 
 tion products is frequently impeded by far-reaching molecular re- 
 arrangements undergone by these bodies, especially with acid reagents 
 (cp. j3-campholenic acid, j3-campholytic acid, etc.). 
 
 Transformation Products of Camphor. Chlorine and bromine 
 convert camphor into mono- and di-substitution products, a- and j3, d- 
 . chloro-camphor melt at 92 and 100. a- and j3-Dichloro-camphor 
 melt at 93 and 77, while a- and jS-bromo-eamphor melt at 76 and 61. 
 On the action of sodium upon bromo-camphor, dicamphor (C 10 H 15 O) 2 , 
 and dicamphene-dione (C 10 H 14 O) 2 , see C. 1898, 1. 295, and B. 37, 1569. 
 With magnesium in ether the a-bromo-camphor yields bromo- 
 magnesium-camphor, which is found to be very suitable for syntheses 
 (B. 36, 2608 ; 37, 749). a- and j3-Dibromo-camphor, m.p. 61 and 
 115 (cp. C. 1897, II. 76) ; on the decomposition of a-dibromo-camphor, 
 see C. 1900, I. 198. a-Iodo-eamphor, m.p. 43, is formed by the 
 saponification of iodo-formyl-camphor, or by the action of iodine upon 
 sodium-camphor. a-Di-iodo-eamphor, m.p. 109, is formed by the 
 action of iodine upon alkaline alcoholic solution of formyl-camphor 
 (B. 37, 2156). 
 
 With PCL camphor gives several camphor dichlorides, dichloro- 
 
 fCH 2 
 camphanes C 8 H 14 | | which, on shaking up with concentrated 
 
 [CClg 
 sulphuric acid, split the bridge linkage, and pass easily into carvenone, 
 
 By heating camphor with alcoholic ammonium sulphide, a mixture 
 of sulphides is obtained which, on distillation, yields thio-eamphor 
 C 10 H 16 S, red crystals, m.p. 119, b.p. ]5 104, and thio-borneol (B. 
 36, 863). 
 
 By heating chloro-camphor and bromo-camphor with nitric acid, 
 or by chlorinating or brominating nitro-camphor, we obtain chloro- 
 and bromo-nitro-camphor, which, on reduction with copper zinc, or 
 on treatment with sodium methylate, give nitro-camphor (B. 22, 
 R. 266 ; 23, R. 115 ; 29, R. 270 ; 37, 2077 ; C. 1899, I. 1078). By 
 reduction, nitro-camphor yields amido-camphor. An isomeric nitro- 
 
 camphor C 8 H i4\/Q|Jv (?), m.p. 70, is formed from iso-nitroso-camphor 
 
 by oxidation with nitric acid (C. 1902, II. 897). 
 
 Camphor-sulphonic acids and their transformation products, see 
 B. 28, R. 643 ; 29, R. 512 ; C. 1898, I. 619 ; 1902, II. 1464 ; 1903, 
 I. 923. The d-camphor-sulphonic acid, and especially the d-bromo- 
 sulpho-camphoric acid, are often useful for splitting up racemic bases. 
 
 Camphor-oxime C 10 H 16 : NOH, m.p. 118, b.p. 249 (A. 259, 331), 
 gives, on reduction, bornylamine. Potassium hypobromite converts 
 
 it into bromo-nitro-eamphane c 8 H i4\CBr(NO) m -P- 220 > wmcn > on 
 reduction, gives nitro-eamphane C 10 H 17 N0 2 , m.p. 148 (C. 1900, 1. 544). 
 By the action of nitrous acid upon camphor-oxime we obtain the 
 
 nitrate of a-camphorimine C 8 H 14 . ^ H (?), m.p. about 95 
 
 with j3-camphorimine and camphenamine, besides a substance C 16 H 16 
 N 2 O 2 , m.p. 43, which is termed pernitroso-camphor or camphenile 
 
CAMPHANE GROUP 533 
 
 nitramine, isomeric with camphor dioximes, and converted by sulphuric 
 acid into a ketone isomeric with camphor (B. 29, 2807 ; C. 1905, II. 
 623). Camphor-oxime and camphor-phenyl-hydrazone, b.p. 210, 
 can also be easily prepared from thio-camphor (B. 36, 868). 
 
 j3-Camphor, bornylone C 8 H 14 <^ , m.p. 185, b.p. 214, structurally 
 isomeric with camphor, is formed by the action of acids upon j3-cam- 
 phorimine C 8 H 14 <^^ NH , obtained from the azide of bornylene-car- 
 
 boxylic acid by Curtius' transposition. In small quantities it is also 
 obtained from ct-oxy-camphane-5-carboxylic acid by oxidation with 
 Cr0 3 (Ch. Ztg. 35, 765). 
 
 Camphor-quinone C 8 H 14 <^, m.p. 198, is formed from iso-nitroso- 
 
 camphor by boiling with dilute sulphuric acid, upon the action of 
 nitrous acid or sodium bisulphite, or by the action of campho-carboxylic 
 acid (B. 27, 1447). It resembles the quinone of the a-diketones, has 
 a peculiar sweet odour, is volatile with steam, and sublimes at 50-6o 
 in golden-yellow needles (A. 274, 71). Camphor-quinone easily passes 
 into camphoric acid derivatives, under the influence of various reagents 
 (cp. B. 30, 657, 659). Concentrated sulphuric acid converts it into a 
 ketonic acid C^HjgOg ; fuming sulphuric acid produces a transposition 
 of camphor-quinone even at 0, with splitting up of the CH 3 .C.CH 3 
 bridge, and enolisation of a keto-group (B. 35, 3829). 
 
 Iso-nitroso-camphor C 8 HX^ ! Q { H exists in two forms, melting at 
 
 153 and 114 respectively (C. 1908, I. 1270) ; it is formed by the 
 action of amyl nitrite and sodium ethylate upon camphor. Concen- 
 trated sulphuric acid converts it into camphoric acid imide (B. 26, 
 241). Acetyl chloride, PC1 3 , or soda and acetic anhydride produce 
 camphoric acid mononitrile (B. 29, R. 651). Zinc and dilute acids 
 produce amido-camphor (A. 274, 71). Camphor - quinone - phenyl- 
 hydrazone C,H M ^^ N IC 6 H 5j m p I ^ > - 1S produced, besides its desmo- 
 
 tropicform C 8 H 14 <^Q ' NC HS , m.p. 180, by the action of diazo-benzol 
 
 chloride upon campho-carboxylic acid (B. 32, 1995 ; cp. C. 1902, 
 II. 210). 
 
 bis-Camphanonazine, azo-camphenone C 8 H 14 <^^ N ' N ^T>C 8 H 14 , m.p. 
 
 222, is obtained from camphor-quinone with hydrazin, and from azo- 
 camphor by heating, together with camphenone (B. 27, R. 892 ; C. 
 1897, II. 761). 
 
 Camphor-dioxime, a-dioxime, m.p. 201, j3-dioxime, m.p. 248, are 
 formed from iso-nitroso-camphor with acetic hydroxylamine. y-Di- 
 oxime, m.p. 135, from iso-nitroso-camphor with free hydroxylamine, 
 on melting, passes into S-dioxime, m.p. 199. The dioximes are dis- 
 tinguished by their optical rotatory power (C. 1903, I. 1352). By 
 reduction they yield the peroxide C 10 H 16 N 2 O 2 , m.p. 144. They are 
 also produced from bromo-pernitroso-camphor, a bromination product 
 of pernitroso-camphor with hydroxylamine (C. 1900, II. 574)- 
 
 a-Oxy-camphor C 8 H 14 <^ HOH , m.p. 203-205, is formed from 
 camphor-quinone by reduction with glacial acetic acid and zinc dust. 
 
534 ORGANIC CHEMISTRY 
 
 It is easily alkylated and acylated. Sodium amalgam reduces it to 
 camphor. Sodium and alcohol, to eamphor-glycol C 8H U <(^Q^> -P- 
 231. This eamphor-glycol is isomeric with the camphene-glycol 
 obtained from camphene with KMn0 4 , and must be regarded as 
 the glycol of bornylene. By oxidation of oxy-camphor, camphor- 
 quinone is regenerated (B. 35, 3811). 
 
 Campherol C 10 H 16 O 2 , m.p. I97-I98, is apparently isomeric with 
 a-oxy-camphor. It occurs in the form of a glucuronic acid compound 
 in the urine of dogs fed with camphor (B. 30, 660). 
 
 /CH.NH 2 
 
 Amido-eamphor C 8 H 14 < | , b.p. 244, from mtro-camphor, or, 
 
 X CO 
 
 better, from iso-nitroso-camphor, by reduction. It is a mass resembling 
 paraffin, and smelling of fish. It condenses on standing to dihydro- 
 camphene-pyrazin C 8 H 14 <^=^ H >C 8 H 14 , m.p. 116, and, as an 
 
 a-amido-ketone, it is suitable for hetero-ring formations (cp. A. 313, 25). 
 Amido-camphor-chlorohydrate, m.p. 224, acts like curare, but much 
 more feebly. Acetyl compound, m.p. 122. Camphoryl-glycoeoll ester 
 C 10 H 15 O.NHCH 2 CO 2 C 2 H 5 is poisonous (A. 307, 207 ; B. 31, 3260 ; 32, 
 
 1538 ; 35, 3657) . Camphoryl-earbamide C 6 H 4 <^' NHCONH2 , m.p. 169, 
 
 from amido-camphor and potassium cyanate, yields, with nitrous acid, 
 camphoryl-iso-cyanate C 10 H 15 O.N : C : O, m.p. 77, a substance very 
 prone to reaction, from which numerous counter-derivatives have been 
 obtained. 
 
 Camphoryl-mustard oil C 10 H 15 O.N : C : S, m.p. 106-5 (C. 1908, 
 
 I- 257)- 
 
 Azo-camphor, monoketazo-camphor-qmnonec^/^^, m.p. 74, 
 
 yellow crystals, is obtained by the action of nitrous acid upon amido- 
 camphor-chlorohydrate (B. 26, 1718) ; with potassium sulphite it 
 gives hydrazin sulphonate, which is split up by concentrated HC1 into 
 hydrazin and camphor-quinone (B. 29, R. 1115). 
 
 Camphenone c 8 H 13 ^?*r(?), m.p. i68-i70, is formed besides azo- 
 
 camphenone by heating azo-camphor. It smells of camphor. Oxime, 
 m.p. 132 (B. 27, R. 590). For the action of bromine and HBr upon 
 camphenone, see B. 29, R. 1108. 
 
 If we wish to attach carbon groups to the camphor amalgam, 
 sodium camphor (C 10 H 15 O)Na, obtained from camphor with sodium 
 and sodium amide, is particularly suitable, and so is camphor-magnesium 
 bromide (C 10 H 15 O)MgBr, obtained from a-bromo-camphor with mag- 
 nesium in ether, in benzene, toluol, etc. By the action of halogen 
 alkyl CO 2 , cyanogen, car boxy lie esters, chlorides or anhydrides, of 
 aldehydes and ketones upon these bodies, the radicles -CH 3 , -CO 2 H, 
 -CN, -COR, -CH(OH)R', -C(OH)RR', =CHR are introduced instead 
 of the hydrogens of the -CH 2 -CO group in camphor. The resulting 
 products are capable of many transformations. 
 
 d-Campho-carboxylic acid C 8 H 14 <^ C 2H , m.p. 128, with evolution 
 of CO 2 . It is formed from camphor with .sodium, or, better, from 
 
CAMPHANE GROUP 535 
 
 sodium amide and CO 2 in benzene, or from bromo-camphor Mg and 
 CO 2 in ether (B. 36, 668, 1305). The acid and its esters : methyl 
 ester, b.p. 15 i55-i6o ; ethyl ester, b.p. 21 167, give green and blue 
 colorations respectively, with ferric chloride. With sodium and 
 alkyline iodide the esters yield alkyl-campho-carboxylic ester : methyl- 
 
 campho-earboxylic methyl ester C 8 H 14 </^ H3)C 2CH3 , m.p. 87 (acid : 
 
 m.p. 104), ethyl-campho-carboxylic ethyl ester, b.p. 15 165. Some of 
 these esters are difficult to saponify. With carboxylic haloids the 
 sodium campho-carboxylic esters change into O-acylated products 
 
 XCO 2 R 
 C 8 H 14 <( II ; but with benzol-sulpho-chloride besides benzol-sul- 
 
 x COAc 
 phinic acid, a-chloro-campho-carboxylic ester is formed. a-Bromo- 
 
 and a-iodo-eampho-carboxylic esters C 8 H 14 <^^ C 2R are easily obtained 
 
 (B. 36, 1732). With phenyl-hydrazin and campho-carboxylic ester, 
 two isomeric campho-phenyl-pyrazalones are obtained (B. 32, 1987). 
 By electrolytic reduction of campho-carboxylic acid in alkaline 
 
 /fTTPOOTT 
 
 solution we obtain cis- and trans-borneol-carboxylic acid C 8 H 14 < XwXSa 
 
 ' XCxiOrl 
 
 m.p. 101 and 171 respectively. KMnO 4 oxidises only the cis-acid 
 of camphoric acid, whereas nitric acid oxidises both. With acetyl 
 chloride both give rise to the aceto-compounds of the trans-acid, m.p. 
 123. By elimination of water both acids, but the cis-acid more 
 
 readily, turn into bornylene-earboxylie acid C 8 H 14 <(^; OOH , m -P- IZ 3 
 
 b.p. 13 158. The latter unites with HC1 or HBr in glacial acetic acid 
 to form j3-chloro- and jS-bromo-hydro-bornylene-carboxylic acid, m.p. 
 85 and 91, the alkaline salts of which, on boiling in aqueous solution, 
 yield bornylene besides other products, and yield it in a particularly 
 pure form. By reduction of j3-bromo-hydro-bornylene-carboxylic acid 
 with potassium amalgam, or of bornylene-earboxylie acid with hydrogen 
 and palladium, we obtain : 
 
 Camphane-5-carboxylic acid C 8 H 14 <^P* C 2H , m.p. 91, which is 
 
 XCHg 
 
 geometrically isomeric with the acid obtained by the action of CO 2 
 upon bornyl-magnesium chloride. 
 
 Camphane - 6 - carboxylic acid, hydro - pinene - carboxylic acid 
 
 //^TT 
 
 C H \CHCOOH' m 'P- 73 ( A - 366, i ; B. 38, 3799)- 
 
 /CHCN 
 
 The nitrile of campho-carboxylic acid, cyano-camphor C 8 H 14 ^ Q , 
 
 m.p. 127, is formed from sodium camphor with gaseous cyanogen, 
 and also from oxy-methylene camphor, by heating with hydroxyl- 
 amine chlorohydrate, which also produces its oxime (A. 281, 349). 
 From sodium cyano-camphor, with alkylene iodide, we simultaneously 
 
 obtain 0- and C-alkyl-cyano-camphor C 8 H 14 <(^ k and c 8 H 14 <^ lk)CN 
 (C. 1903, I. 1085) ; from the latter, by saponification and elimination 
 of CO 2 , we obtain the alkyl camphor methyl-camphor C 8 H 14 <^^' CHs , 
 
 m.p. 38, [a] D -f-27, which, with bromine, produces methyl-bromo- 
 camphor, which, in turn, on treatment with alcoholic potash, yields 
 methylene-camphor C 10 H U O : CH 2 , m.p. 30-35, b.p. 218, [a 
 
536 ORGANIC CHEMISTRY 
 
 (C. 1903, I. 971). Ethyl-camphor, b.p. 226-229, [a] D +40, yields 
 after the same treatment ethylidene-camphor (C 10 H 14 O) : CHCH 3> b.p. 10 
 IIO-II5, [a] D + H3 (C. 1904, I- 948). 
 
 Dimethyl-camphor C S H U <(^ H ^*, b.p. n 106, a mobile liquid 
 
 smelling at the same time of camphor and menthone. It is formed by 
 the action of sodium amide and methyl iodide upon camphor in ether 
 or benzene solution ; by heating with NaNH 2 it is split up to form 
 the amide of dimethyl-campholic acid, m.p. 74 (C. 1909, II. 442 ; 
 cp. Fenchone). 
 
 /P . ftTOT-T 
 
 Oxy-methylene-eamphor, formyl-camphor C 8 H 14 <^ . ' , m.p. 80, 
 
 b.p. 28 138, is formed from sodium-camphor or camphor-magnesium 
 bromide and formic ester, as well as by the action of sodium 
 methylate free from alcohol upon a-monohalogen and dihalogen 
 camphor (B. 37, 2069) ; the oxy-methylene-camphor is a strong 
 acid: methyl ether (C 10 H 14 O) : CHOCH 3 , m.p. 40, b.p. 262; acetate 
 (C 10 H ]4 O) : CHOCOCH 3 , m.p. 63, b.p. 29O-293 ; with PC1 3 , chloro- 
 methylene-camphor (C 10 H 14 O) : CHC1, b.p. 16 119 is generated ; with 
 bromine and iodine in neutral solution we obtain bromo- and iodo- 
 formyl-camphor, m.p. 41 and 68 respectively. With nascent prussic 
 
 X^vTT 
 
 acid we obtain the cyano-hydrin (C 10 H 15 O)CH<_ , m.p. 122, which, 
 
 on boiling with acetic anhydride, yields cyano-methylene-camphor 
 (C 10 H 14 O) : CHCN, m.p. 46, b.p. 280, the nitrile of camphor- 
 methylene-carboxylic acid (C 10 H 34 O) : CHCO ? H, m.p. 101 (A. 281, 306). 
 By reduction of the formyl-camphors with sodium and alcohol we 
 obtain two stereo-isomeric camphyl-glycols C 8 H 14 / H - CH2 H , cis-glycol, 
 
 \CHOH 
 
 m.p. 87, trans-glyeol, m.p. 118. KMnO 4 oxidises the trans-glycol 
 into trans-borneol-carboxylic acid, while the cis-glycol probably with 
 intermediate formation of the cis-borneol-carboxylic acid, which is 
 attacked by KMnO 4 , yields camphoric acid (A. 366, 62). 
 
 The homologous acyl-camphors C 8 H 14 </9i C ( OH)R (desmotropic 
 
 ^\s\J 
 
 forms : C 8 H 14 ^H.C( R and ^^OCOR^ ig obtained from camphor- 
 magnesium bromide with fatty-acid esters, chlorides, and anhydrides, 
 in which case dicamphonyl-alkyl-carbinols (C 10 H 15 O) 2 C(OH)Alk occur 
 as intermediate products (B. 36, 2663 ; 37, 762) ; or by the action of 
 alkyl-magnesium compounds upon cyano-camphor (C. 1906, I. 1468). 
 Acetyl-, propionyl-, butyryl-, i-valeryl-camphor, b.p. n 118, 129, 132, 
 I4i-i48. Benzoyl-camphor, two forms, m.p. 87-88, m.p. 89 
 respectively, is also formed from sodium camphor with benzoyl chloride 
 in toluol (C. 1903, I. 233, 458). 
 
 By the condensation of camphor-magnesium bromide, with alde- 
 hydes and ketones in ether, we obtain secondary and tertiary alcohols, 
 some of which split off water : camphoryl-methyl-carbinol (C 10 H 15 O)CH 
 (OH)CH 3 , b.p. 223-226, is formed from camphor-magnesium bromide 
 with acetaldehyde in small quantities, together with acetyl-camphor. 
 From benzaldehyde and camphor-magnesium bromide we only obtain 
 benzoyl-camphor. From sodium-camphor and benzaldehyde we obtain 
 benzylidene-camphor (C 10 H 14 O)CHC 6 H 5 , m.p. 96, which is also formed 
 
CAMPHANE GROUP 537 
 
 by reduction of benzoyl-camphor, and which, on further reduction, 
 yields benzyl-camphor (C 10 H 15 O)CH 2 C 6 H 5 , m.p. 128, and is split up 
 by heating with HBr to benzylidene-campholic acid c ' H "<(cooH HC ' H5 ' 
 their aromatic aldehydes condense, like benzaldehydes, with sodium- 
 camphor (C. 1901, II. 418). From (C 10 H 15 O)MgBr with acetone we 
 obtain camphoryl-dimethyl-carbinol (C 10 Hi 6 O)C(OH)(CH 8 ) 2 , m.p. 88, 
 b.p. 2io-2i5, which, on boiling with dilute sulphuric acid, yields 
 iso-propylidene-camphor (C 10 H 14 O) : C(CH 3 ) 2 , b.p. 200-204 ; cam- 
 phoryl-diphenyl-carbinol (C 10 H 15 O).C(OH)(C 6 H 5 ) 2 , m.p. 122, from 
 (C 10 H 15 O)MgBr with benzo-phenone (B. 36, 2627). 
 
 With oxalic ester and sodium ethylate, camphor condenses to 
 
 camphor-oxalic acid C 8 H 14 <(- COC )OH , m.p. 88, from which a number 
 
 of derivatives have been prepared (C. 1900, I. 905 ; 1901, II. 544 ; 
 1908, I. 1182). 
 
 Broken Ring-products of Camphor. The splitting up of the camphor- 
 ring system can take place in two ways in its first phase. In one way 
 the bridge group CH 3 CCH 3 of camphor, which is always in a strong 
 state of strain, " rises up." On the other hand, the splitting may take 
 place at the keto-group of camphor, in which case derivatives of the 
 5-membered camphoceane-ring contained in camphor are formed 
 (A. 299, 162). Examples of the former kind are shown by the 
 transformations of camphor into cymol, carvacrol, and carvenone : 
 
 CH 2 -CH CH 2 CH 3 CHCH 3 
 
 Camphor CH 3 CCH 3 | > CH a C= =&* Qaxveaxme. 
 
 CH 2 C(CH 3 ).CO CH 2 CH(CH 3 ).CO 
 
 An analogous reaction is the transformation of camphor-quinone 
 by fuming sulphuric acid (cp. the splitting up of carone and pinene, 
 above.) 
 
 The second group of disintegrations comprises the transformations 
 of camphor into campholic acid, campholenic acid, and camphoric 
 acid. 
 
 f*T-T 
 
 (a) Campholic acid C 8 H 14 JJJ* , m.p. 107 (active), m.p. 109 (in- 
 
 L/OOrl 
 
 active), is formed by heating camphor-borneol or iso-borneol with caustic 
 potash to 250-28o (B. 28, R. 376 ; C. 1909, I. 1562). By boiling 
 with nitric acid it is oxidised to camphor-camphoric acid and cam- 
 phoronic acid (B. 27, R. 752) ; on the other hand, campholic acid can 
 be recovered from camphoric acid by reducing camphoric anhydride 
 to a-campholide, converting the latter with HBr into bromo-campholic 
 acid and heating this with zinc dust to 50-6o (C. 1900, I. 603). 
 Anhydride, m.p. 58 (inactive), m.p. 66 (inactive). Chloride, b.p. 222, 
 decomposes on heating with P 2 O 5 into HC1, CO, and campholene. 
 The amide melts at 79 (active) and 90 (inactive). 
 
 The nitrile melts at 72 and boils at 218. It yields campholamine, 
 C 10 Hi 9 NH 2 , melting at 210, upon reduction. Bromine and caustic 
 alkali change the amide to camphelyl-iso-cyanate, boiling at 201, from 
 which camphelamine CgN^NHa, melting at 43 and boiling at 175, is 
 obtained (B. 26, R. 21 ; 27, R. 126). Iso-campholic acid, B. 29, R. 
 356. The camphor-ring in camphor-oxime can be very easily ruptured 
 
53 8 ORGANIC CHEMISTRY 
 
 by mineral acids, the products being a- and j8-campholene-nitrile, 
 iso-amino-camphor, and dihydro-campholene-lactone. 
 
 CH 2 CH CH 2 
 
 a-Campholenie acid | >C(CH 3 ) 2 | boils at 256. Its 
 
 CH^C CH 3 COOH 
 
 specific gravity equals 0-992 (19). It is optically active, n D = 1-47125. 
 The nitrite, b.p. 226, of this acid is produced with water exit when 
 dilute sulphuric acid or acetyl chloride acts upon camphor-oxime. 
 The reduction of the nitrile produces a-camphylamine C 10 H 17 NH 2 , 
 boiling at 195. Alcoholic potash saponifies it to a-campholamide, 
 melting at 130, which with alkali hypobromite gives the lower homo- 
 logue of camphylamine, a-amido-campholene C 9 H 15 NH 2 , b.p. 185 
 (C. 1899, II. 385), and on further saponification campholenic acid. 
 The latter is oxidised by potassium permanganate to : 
 
 a-Dioxy-hydro-eampholenic acid C 9 H 15 (OH) 2 CO 2 H, melting at 
 144, and a ketonic acid, 1-pinonic acid, which affords decomposition 
 products similar to those of the like-named oxidation product of 
 pinene. Chromic acid oxidises a-campholene- or dihydro-dioxy- 
 campholenic acid to iso-keto-camphoric acid C 10 H 16 O 5 =CH 3 .CO. 
 C(CH 3 ) 2 CH(CH 2 COOH)o, and, eventually, to iso-eamphoronic acid 
 C0 2 H.C(CH 3 ) 2 CH(CH 2 COOH) 2 (A. 289, 19; C. 1899, II. 833), m.p. 
 167. Concentrated sulphuric acid, when warmed with the latter 
 body, sets free CO, and terpenylic acid results (B. 29, 3006). 
 
 Campholenic acid is stable in the presence of alkalies, but acids 
 transpose it in a peculiar manner (Ch. Ztg. 1900, 858) into 
 
 CHo 
 
 >CH 3 I . 
 
 H 2 C.(CH 3 ) 2 COOH 
 
 ^ 
 
 I 
 
 j8-eampholenie acid, melting at 52 and boiling at 245, which is 
 optically inactive. Its nitrile, boiling at 22O-23O, is produced in the 
 action of stronger acids (concentrated HI) upon camphor-oxime. It is 
 reduced to j3-eamphylamine, melting at 197, which may be saponified 
 to an amide, melting at 86. Potassium permanganate oxidises 
 jS-campholenic acid to a dihydroxy-acid, melting at 146, and with it 
 an oily acid which readily changes to iso-camphorone C 9 H 14 O, boiling 
 at 217. Chromic acid oxidises the j3-acid to y-acetyl-iso-eapronic acid 
 CH 3 .CO.C(CH 3 ) 2 CH 2 CH 2 COOH, melting at 48. Further oxidation 
 leads to a decomposition into a-dimethyl-glutaric acid and a-dimethyl- 
 succinic acid. The same decomposition products are obtained from 
 iso-camphorone (B. 30, 242). The conversion of j3-campholenic acid, 
 when heated with bromine, into I, 3, 4-xylyl- acetic acid (B. 29, R. 
 643) is peculiar. 
 
 j8-Dihydro-eampholene-lactone, melting at 30 and boiling at 
 256, appears as the principal or the by-product in the decomposi- 
 tions of camphor-oxime by strong acids, and may be obtained by 
 acids from the two campholenic acids, as well as from iso-amino- 
 camphor. 
 
 Synthetically, it is prepared by the action of CH 3 MgI upon 3, 3- 
 
 CH 2 .CH CH 2 .CO 2 R 
 
 dimethyl-cyclo-pentanone-acetic ester >CO (C. 1908, 1. 1056). 
 
 CH 2 .C(CH 3 ) 2 
 
CAMPHANE GROUP 539 
 
 Chromic acid oxidises it to oxy-dihydro-campholene-lactone, melting 
 at 144 (B. 30, 404). 
 
 Iso-amino-camphor C 10 H 17 ON, boiling at 254, is formed along with 
 the preceding bodies when stronger acids act upon camphor-oxime, 
 campholene-amides, and nitriles. It apparently contains a primary 
 amine group, and is very similar to the isomeric amido-camphor. It 
 changes quite readily to dihydro-campholeno-lactone (B. 30, 324). 
 
 a-Dihydro-campholenic acid C 10 H 18 O 2 , b.p. 22 160 ; the nitrile, b.p. 
 225-228, of this acid is obtained by heating the isomeric camphor- 
 imine with access of air (B. 33, 1929). By bromination, and elimina- 
 tion of HBr, we obtain the isomeric acid (C 8 H U ) : CHCOOH, m.p. 70, 
 isomeric with campholenic acid, and this becomes 2, 3, 3-trimethyl- 
 
 cyclo-pentanone, m.p. 165, on oxidation with KMnO 4 (C. 1902, 1. 585). 
 ftr rvpTT ^ 
 
 Campholene I ^CCH 3 (?), boiling at 134, is produced 
 
 tH 2 C(CH 3 )/ 
 
 when a- or, better, j3-campholenic acid has been heated. Carbon 
 dioxide is eliminated. It is, further, formed from campholic acid or 
 campholic acid chloride, when acted upon with P 2 O 5 . Synthetically, 
 it has been obtained by the action of CH 3 MgI upon i, i, 4-trimethyl- 
 cyclo-pentanone-5, and elimination of water from the resulting tetra- 
 methyl-cyclo-pentanol (C. 1907, II. 2050). It is optically inactive, 
 and yields on oxidation jS/J-dimethyl-lsevulinie acid CH 3 COC(CH 3 ) 2 
 CH 2 COOH, and unsym. dimethyl-succinic acid. 
 
 Campholene dibromide melts at 97. Campholene, heated with 
 HI acid to 280, becomes hexahydro-pseudo-cumol, just as jS-campho- 
 lenic acid changes to xylyl-acetic acid (B. 30, 594), and camphoric acid 
 to tetrahydro-iso-xylol (B. 26, 3053). 
 
 An apparently isomeric Campholene C 9 H 16 , boiling at 137, has been 
 obtained together with carvacrol from chloro-camphor by the action of 
 zinc chloride (B. 26, R. 492). 
 
 Camphoric Acid. There are four optically active, and two optically 
 inactive, camphoric acids. 
 
 CH, CH COOH 
 
 d-Camphoric acid, ordinary camphoric acid C(CH 3 ) 8 
 
 CH 2 C(CH 3 ) COOH 
 
 m.p. 187, [a] D = +497 in alcohol, is obtained by heating d-camphor, 
 or campholic acid, with nitric acid (A. 163, 323), and, because it can be 
 made without great trouble, has been exhaustively studied. When it 
 is heated above the melting-point, or when it is treated with acetyl 
 chloride (A. 226, i), it changes to its anhydride, melting at 221 and 
 boiling at 270. Synthesis of camphor, see above. 
 
 By fusion with caustic potash, camphoric acid changes to iso-propyl- 
 succinic acid and 1-iso-camphoric acid ; by oxidation with nitric 
 
 (CH 3 ) 2 C.C0 2 H 
 acid, camphoronic acid and dinitro-capronic acid are 
 
 CH 3 .(!:(N0 2 ) 2 
 
 produced, while with chromic acid the products are camphoronic 
 and trimethyl-succinic acids. Water and bromine change it to cam- 
 phanic acid (B. 28, 2151). On oxidising camphoric acid with perman- 
 ganate, we obtain, besides oxalic acid as a characteristic product, a 
 dibasic acid C 8 H 12 O 5 , m.p. 121, which can be divided into optical 
 antipodes. On reduction with HI, it yields ajSjS-trimethyl-glutaric 
 
540 ORGANIC CHEMISTRY 
 
 acid, and the anhydride of aj8j8-trimethyl-glutaric acid, resembling 
 ethylene oxide. Its formula and formation may be represented as 
 follows : 
 
 CH 2 CH COOH CH COOH 
 
 C(CH 3 ) 2 --> gg *+0<C(CH 3 ) 2 
 
 CH 2 C(CH 3 ) COOH X C(CH 3 ) COOH. 
 
 The distillation of calcium camphorate yields camphorone 
 
 CHlII^CH(CH 3 ] )^ C0 ' b ' P ' 10 83 (R 26 ' 3 53) ' In this reaction there 
 is not only a cyclic ketone formation, but an " erection " of the 
 camphor bridge CH 3 .C.CH 3 . The constitution of camphorone, first 
 deduced from the oxidation products, is confirmed by its synthesis 
 from 2-methyl-cyclo-pentanone and acetone, with sodium ethylate 
 (C. 1900, I. 604), and its breaking up into these components, on heating 
 with caustic potash (A. 331, 322), as well as its behaviour towards 
 hydroxylamine, with which it gives an addition product, camphorone- 
 hydroxylamine C 9 H 15 O(NHOH), m.p. 120 (B. 32, 1343). By reduc- 
 tion with sodium and alcohol we obtain a secondary alcohol, dihydro- 
 camphorol C 9 H 17 .OH, and from this, with CrO 3 , we obtain dihydro- 
 eamphorone C 9 H 16 O, b.p. i84-i85 (B. 37, 236), identical with 
 dihydro-pulegenone, and obtained synthetically from a-methyl-a!- 
 iso-propyl-adipinic acid (C. 1908, I. 1056). 
 
 Tetrahydro- and hexahydro-isoxylol are produced when camphoric 
 acid is heated with hydriodic acid. 
 
 The d-camphoric acid forms two series of acid esters : the a-esters, 
 produced by the partial saponification of the neutral esters, and the 
 j8-esters, resulting from the partial esterification of the acids (B. 26, 
 289). For derivatives of ester acids, see C. 1906, I. 35. 
 
 The dichloride C 8 H 14 /^ l2 \O boils at 140 (15 mm.) (B. 23, 
 
 \V-*vJ / 
 
 R. 229). 
 
 The diamide C 8 Hi 4 C 2 O 2 (NH 2 ) 2 , melting at 197, is converted by- 
 potassium hypobromite into C 10 H 16 N 2 O 2 , melting at 235. This is 
 probably the ureide of an oxy-acid (B. 27, R. 894), corresponding to 
 campho-lactone. Two isomeric camphor-amido-aeids, a-, m.p. 177, 
 and j8-, 180, have been obtained from the anhydride with ammonia, 
 and from iso-nitroso-camphor with HC1 (B. 29, R. 96). The j8-acid 
 has been obtained from camphor-imide, with sodium hydroxide (B. 
 29, R. 96 ; C. 1904, II. 1222). See below for decomposition products 
 of these acids. 
 
 The imide C 8 H 14 C 2 O 2 NH, melting at 248 and boiling at 300, is 
 also formed from iso-nitroso-camphor (B. 26, 58, 242 ; A. 257, 308 ; 
 328, 342), and from camphoric anhydride by distillation in a current 
 of NH 3 . In sulphuric acid solution, camphoric acid imide is reduced at 
 
 //"*T T \ 
 
 lead electrodes to two isomeric lactames, camphidonene C 8 H 14 <^~* 2 \NH, 
 
 \V>-V-/ w 
 
 a-form, m.p. 231, b.p. 295, j8-form, m.p. 228, b.p. 308, and 
 further to the base camphidin C 8 H 14 (CH 2 ) 2 NH, m.p. 186, b.p. 209 
 (B. 34, 3274). a- and j5-Camphidone are also formed by heating the 
 chlorohydrates of a- and j8-amido-campholic acids (see below), the 
 lactames of which are probably the camphidones (B. 40, 4311). 
 Nitroso-a-camphidone, on heating with alkali, passes into a- 
 
CAMPHANE GROUP 541 
 
 campholide (B. 38, 3806). Thio-camphoric acid imide C 8 H 14 (CS) 2 NH, 
 m.p. 135 (C. 1910, I. 1253). 
 
 The methyl imide C 8 H U /^\NCH 3 , m.p. 40-42, is obtained 
 
 . \UvJ/ 
 
 from silver camphoron-imide and methyl iodide, as well as by heating 
 methyl iso-imide above its melting-point (B. 29, R. 96). 
 
 Methyl iso-imide c 8 H i<' CH8 , melting at 134, results when 
 
 camphor-methyl-amino-acid is treated with acetyl chloride or PC1 3 
 (B. 26, R. 688). 
 
 Camphoryl-hydroxylamine C 8 H 14 <^>N.OH melts at 225 (B. 27, 
 
 R. 893). It seems to be identical with so-called camphor nitro-phenol, 
 obtained by boiling nitro-camphor in HC1 (C. 1899, I. in). 
 
 a-Camphor-nitrilic acid, cyano-lauronic acid C 8 H 14 (CN)COOH, 
 melting at 152, is formed when camphor-amino-acid is treated with 
 acetyl chloride and subsequently with ammonia, or by the interaction 
 of acetic anhydride or PC1 5 and iso-nitroso-camphor (B. 29, R. 651, 
 
 779)- 
 
 j8-Camphor-nitrilic acid, m.p. iio-ii3, from p-camphor-amido- 
 acid. On distillation of their calcium salts both isomeric acids break 
 the ring, and yield the nitrile of dimethyl-heptenic acid (CH 3 ) 2 C : CH. 
 CH 2 .CH 2 .CH(CH 3 )CN, b.p. 14 89-90, which is also produced by 
 the distillation of camphoric acid imide, and camphor-amido-acids 
 with lime, and represents the lower homologue of citronellic acid 
 nitrile (A. 328, 338). By reduction with sodium and alcohol, a- and 
 j3-camphor-nitrilic acid are reduced to a- and j8-amido-campholic 
 acid C 8 H 14 (CH 2 NH 2 )COOH. Their chlorohydrates, a-, m.p. 248, 
 j8-, m.p. 2i5-222, on heating turn into a- and j8-camphidone 
 (B. 40, 4311). 
 
 1- Camphoric acid results from the oxidation of matricaria camphor. 
 It resembles the d-variety in every particular, except the rotatory 
 power. 
 
 [d-f-1]- Camphoric acid, paracamphoric acid, melting at 204, is 
 formed upon mixing alcoholic solutions of equimolecular quantities 
 of d- and 1-camphoric acids (B. 23, R. 229). 
 
 d-Iso-camphoric acid, d-cis-trans-camphoric acid, melting at 171, 
 with [a] D =+48, may be prepared by heating 1-camphoric acid with 
 water, or, better, with a mixture of glacial acetic acid and hydro- 
 chloric acid, which produces some dextro " iso-camphoric " acid. It 
 does not form a real anhydride, hence can be easily separated by means 
 of acetyl chloride from the 1-camphoric acid. 
 
 1-Iso-camphoric acid, [a] D = 48, is obtained from both d- 
 camphoric acid and its chloride. 
 
 [d-f 1] -Iso-camphoric acid, melting at 191, results from the union 
 of d- and 1-iso-camphoric acids. When they are heated the corre- 
 sponding camphoric anhydrides are produced (B. 27, 2001). Cp. B. 29, 
 1700, for the crystal forms of the camphoric acids. 
 CH 2 C(CO 2 H).O 
 
 Camphanic acid | CH 3 CCH 3 | , melting at 201, is obtained 
 
 CH 2 C(CH 3 ) CO 
 
 on boiling bromo-camphoric anhydride with water. Nitric and 
 chromic acids oxidise it to camphororiic acid. By distillation cam- 
 
542 ORGANIC CHEMISTRY 
 
 phanic acid loses carbon dioxide, and becomes campho-lactone and 
 lauronolic acid (A. 227, i). Cp. B. 29, R. 772, 861, for additional 
 bromo- and oxy-camphoric acids. 
 
 On the breaking up of camphanic acid nitrile to camphononic acid, 
 a 2, 2, 3-trimethyl-cyclo-pentanone-3-carboxylic acid, see C. 1901, 
 
 II. 1308. 
 
 CH=C.C0 2 H 
 
 Dehydro-camphorie acid | CH 3 CCH 3 , m.p. 202-203, is 
 
 CH 8 C(CH 3 )C0 2 H 
 
 obtained by heating chloro- and bromo-camphoric acid ester with 
 quinolin or diethyl-aniline, and subsequent saponification. It does 
 not itself form an anhydride, but, on distillation, it shifts the 
 double link, and passes into the anhydride of iso-dehydro- camphoric 
 acid (acid, m.p. I78-I79 ; anhydride, m.p. i82-i83). Lauronolic 
 acid (see below) is also produced, with elimination of CO 2 (B. 
 35, 1286). 
 
 On treating the two camphor-amido -acids with bromine and alkali, 
 two isomeric amino-acids are produced : a - camphor - amido - acid 
 yields amino-dihydro-lauronolic acid, and j3-camphor-amido-acid, 
 amino-dihydro-a-campholytic acid : 
 
 CH a CH.CONHj CH a CH.NH, CH a CH.COOH CH a CH.COOH 
 
 >C(CH,) S > | >C(CH,) 2 >C(CH 4 ) a > | >C(CH,) a . 
 
 CH a .C(CH,).COOH CH 2 .C(CH S )COOH CH 2 .C(CH,).CONH a CH 2 .C(CH a ).NH a 
 
 Amino-dihydro-lauronolic acid (also called amino-lauronic acid), 
 treated with acetic anhydride, gives a lactame C 8 H 14 ^ , the 
 
 nitroso-compound of which, on boiling with potash, forms some com- 
 pounds which include the corresponding lactone, dihydro-lauro- 
 
 O 
 lactone C 8 H 14 <J , m.p. 32 (B. 35, 1291; C. 1909, I. 1095). The 
 
 amino-dihydro-a-campholytic acid, which can also be formed from 
 camphoric acid chlorimide, with sodium alcoholate, also yields a 
 
 lactame and, in the same way, a lactone C 8 H 14 <\. , dihydro- 
 eampholyto-laetone, m.p. 116 (A. 314, 392). 
 
 Lauronolic acid | /^(CHg)., ( a i so ca n ec i y-lauronolic acid 
 
 CH 2 C(CH 3 ) COOH 
 
 or allo-campholytic acid) is formed from amino-dihydro-lauronolic 
 acid with nitrous acid, and from dehydro-camphoric acid, by splitting 
 off CO 2 . By oxidation in KMnO 4 or nitric acid, and splitting at the 
 double link, it yields camphoronic acid (see below). 
 
 CH 2 C.CH 3 
 Iso-lauronolic acid C.CH 3 (?) (Woringer's lauronolic 
 
 CH 2 C(CH 3 )CO 2 H 
 
 acid) is formed from camphanic acid by distillation, and from bromo- 
 camphoric anhydride with soda. On boiling with HC1, lauronolic acid 
 and iso-lauronolic acid give the same y-lactone, iso-dihydro-lauro- 
 
 lactone (formerly called campho-lactone) C 8 H 14 /| , m.p. 50, iso- 
 
 Nbo 
 
 meric with the dihydro-lauro-lactone (B. 35, 1290 ; /. pr. Ch. 2, 83, 
 400). 
 
CAMPHANE GROUP 543 
 
 CH a CH COOH 
 a-Campholytic acid | ^C(CH 3 ) 2 , liquid, b.p. 15 140, is formed 
 
 CH=C(CH 3 ) 
 
 in the action of nitrous acid upon dihydro - amino - campholytic 
 acid (see above) (besides oxy-dihydro-campholytic acid C 8 H 14 (OH) 
 COOH, m.p. 132, and its lactone, m.p. 116), and by electrolysis of 
 the potassium salt of a-camphor-methyl-ester acid. By oxidation 
 with nitric acid, a-campholytic acid is oxidised to dimethyl-triearbal- 
 lytic acid COOH.C(CH 3 ) 2 .CH(COOH).CH 2 COOH (B. 33, 2935). By 
 dilute sulphuric acid it is transposed, like a- into j3-campholenic 
 
 CH, C C0 2 H 
 
 acid (see above), into j8-eampholytic acid | ^CCH 3 , m.p. 134 
 
 CH, C : (CH 3 ), 
 
 (formerly called iso-lauronolic acid). It is formed out of camphoric 
 anhydride by the action of A1C1 3 (cp. C. 1900, I. 545 ; 1901, I. 78) ; it 
 is also obtained by heating sulpho-camphylic acid to 200. On heating 
 with concentrated sulphuric acid, sulpho-camphylic acid is regenerated 
 from j3-campholytic acid. The jS-campholytic acid contains no unsym. 
 C atom, and is therefore optically inactive. On oxidation with 
 chromic acid it yields, like j3-campholenic acid, dimethyl-hexanonic or 
 acetyl-capronic acid CH 3 COC(CH 3 ) 2 CH 2 CH 2 COOH and a-dimethyl- 
 glutaric acid (A. Ch. Phys. 7, 18, 181 ; C. 1899, n - 8 7 J '. C P- A - 314 
 
 39 2 )- 
 
 On a synthesis of a- and j8-campholytic acid from I, i-dimethyl- 
 
 butane-i, 2, 4-tricarboxylic acid, see C. 1903, I. 923. On the dis- 
 
 integration of dihydro-a- and -j3-campholytic acid to 2, 2, 3- and 
 
 2, 3, 3-trimethyl-cyclo-pentanone, see C. 1902, II. 265 ; 1903, II. 287. 
 
 CH 2 CH 
 
 Iso-laurolene | ^CCH 3 , b.p. 108, is formed on heating iso- 
 
 CH a C:(CH 3 ) 2 
 
 lauronolic acid to 300. Synthetically, it has been obtained by the 
 action of CH 3 MgI upon 2, 2-dimethyl-cyclo-pentanone, and elimina- 
 tion of water from the resulting alcohol. With KMnO 4 , dimethyl- 
 hexanonic acid is formed, as in the case of j8-campholytic acid. With 
 acetyl chloride and A1C1 3 , it yields, like the aromatic hydrocarbons, a 
 ketone isomeric with camphor : j3-campholyto-methyl-ketone C 8 H 13 
 (COCH 3 ), b.p. 202, also obtained from the chloride of j3-campholytic 
 acid, with zinc methyl and potassium hypobromite (C. 1909, I. 751). 
 
 Laurolene ' 3 (?) ' b ' p ' I2I ' is formed b heat> 
 
 ing camphanic acid with water to 180, and from the nitroso-compound 
 of amino-laurolonic acid lactame, by boiling with soda (C. 1909, II. 
 801). 
 
 / 
 
 Sulpho-camphylic acid, sulpho-camphoric acid C 8 H 12 <(^;r +3H 2 o, 
 
 2 
 
 \ 
 
 melting at i6o-i65, is produced in the action of sulphuric acid upon 
 camphoric acid. Upon heating it changes to j8-campholytic acid ; on 
 fusing with soda, two acids are formed, C 9 H 12 O 2 , a- and j3-camphylic 
 acid, m.p. 148 and 106 respectively. The former is reduced by 
 sodium amalgam to inactive a-campholytic acid (see above, and C. 1902, 
 II. 366 ; 1903, II. 571). On oxidising sulpho-camphylic acid with 
 permanganate at o, it changes into the so-called camphorylic acid 
 
544 ORGANIC CHEMISTRY 
 
 C 18 H 20 O 6 , a diketocarboxylic acid (C. 1899, 1. 931), and upon oxidation 
 with nitric acid it yields sulpho-iso-propyl-succinic acid and dimethyl- 
 malonic acid (B. 26, 2044). 
 
 CH 2 CH CH 2 , 
 a-Campholide | C(CH 3 ) 2 /> melting at 211, is formed in 
 
 CH 2 C(CH 3 ).CO 
 
 the reduction of camphoric anhydride with alcohol and sodium, just 
 as phthalide is obtained from phthalic anhydride (B. 29, R. 221, 288). 
 Also by heating nitroso-a-camphidone with alkali, and by oxidising 
 camphor with Caro's acid (B. 32, 3630). With PC1 5 the lactone gives 
 chloro-campholie acid chloride C 8 H 4 (CH 2 C1)COC1, m.p. 21, b.p. 16 132 ; 
 by treatment with HBr, bromo-campholic acid C 8 H 14 (CH 2 Br)COOH, 
 m.p. 177 with decomposition, which, by reduction, passes into cam- 
 pholic acid, and, with PC1 5 , into bromo-campholic acid chloride, m.p. 
 
 37, b-P-15 147; j3-campholide c 8 H u<(^ />o, m.p. 219, is formed 
 
 in small quantity by reduction of camphoric acid j3-methyl ester with 
 Na and alcohol (C. 1906, 1. 35 ; cp. B. 40, 4311). Dialkyl-a-campholides, 
 like dimethyl- and diethyl-a-campholide, b.p. 10 146 and m.p. 38, are 
 obtained by the action of alkyl-magnesium haloids upon camphoric 
 acid ester, or camphoric anhydride. In the latter case there are by- 
 products in the shape of the corresponding campholides : dimethyl-jS- 
 
 campholide, m.p. 84 (C. 1910, II. 467). 
 
 CH 2 CH^-COOH 
 
 /C(CH 3 ) 2 
 
 Carboxyl-apo-camphoricacid,c^w/)^o-ac^cH 2 C=-COOH , melting 
 
 COOH 
 
 at I96-20O, is produced in the oxidation of camphene with dilute 
 nitric acid. It forms an anhydride acid when it is heated. This melts at 
 205. It subsequently splits off C0 2 and passes into the anhydride of : 
 
 CH 2 CH COOH 
 Apo-camphoric acid, campho-pyro-acid ^>C(CH 3 ) 2 , melting 
 
 CH 2 CH COOH 
 
 at^204, which is also formed by oxidising fenchene with nitric acid. 
 It is synthesised by a series of suitable reductions from diketo-apo- 
 camphoric acid (cp. synthesis of camphor) and obtained in a cis- and 
 a trans- form (m.p. 204 and 190 respectively). The anhydride of 
 the former melts at 175 (A. 368, 126). In accordance with its sym- 
 metrical formula, apo-camphoric acid is optically inactive. 
 
 C=C(C0 2 C 2 H 6 ) 2 
 d-Camphoryl-malonic acid ester C 8 H 14 / >o , m.p. 82, 
 
 x co 
 
 b.p. 40 247, by the action of Na-malonic ester upon camphoric acid 
 chloride (A. 257, 298). Similar compounds are obtained by the 
 transformation of chloro- and bromo-campholic acid chloride with 
 Na-malonic methyl ester, which gives, besides halogen esters 
 
 C 8 H 14 CH , , m.p. 56 and 73, an ester free from halogens 
 
 _ 
 
 >C(C0 2 CH 3 ) 2 (?), m.p. 79 (R. Anschiitz). Otherwise it 
 
 behaves analogously to camphoric acid (B. 29, R. 175, 773 ; Ch. Ztg., 
 1896, p. 840). 
 
 d-Ho mo-camphoric acid, hydro xy-campho-carboxylic acid 
 
CAMPHANE GROUP 545 
 
 2 H IH , melting at 234, is produced when cyano-camphor is 
 
 boiled with aqueous caustic potash. Its mononitrile is formed on heat- 
 ing campholide with potassium cyanide (B. 29, R. 288). d-Camphor 
 is obtained on heating calcium homo-camphorate in a current of carbon 
 dioxide. 
 
 d-Hydro-eamphoryl-acetic acid C 8 H 14 <^^^ H - CO 2 H , melting at 
 
 142, is produced when hydro-camphoryl-malonic acid is heated (A. 
 257, 303). 
 
 d-Hydro-camphoryl-malonie acid C * U "( 2 H :o * U} \ melting at 
 178, is obtained by the reduction of camphoryl-malonic ester. (A. 257, 
 301). 
 
 Camphoronic acid, aa B - trimethyl - tricarballylic acid 
 
 (CH 3 ) 2 C C(CH 3 ) CH 2 
 
 is produced in the oxidation of camphoric 
 COOH COOH COOH 
 acid, lauronolic acid, and campholic acid with nitric acid. 
 
 It has been synthesised in the following manner. Aceto-acetic 
 ester and a-bromiso-butyric ester, or a-dimethyl-aceto-acetic ester 
 and brom-acetic ester, are condensed by zinc to j-oxy-a, j3-trimethyl- 
 glutaric ester COOR.CH 2 C(OH)(CH 3 )C.(CH 3 ) 2 COOR, which PC1 5 con- 
 verts into the ester of the j8-chloro-acid, and the latter is then changed 
 by potassium cyanide to the ester of j8-cyano-aa^-trimethyl-glutaric 
 acid, the mononitrile of camphoronic acid, which is then saponified to 
 camphoronic acid. The synthetic acid is racemic, while the cam- 
 phoronic acids have the rotation of the original camphoric acids 
 (C. 1898, 1. 248 ; A. 302, 53). 
 
 The importance of camphoronic acid in the determination of the 
 constitution of camphor has been explained. Camphoronic acid melts 
 at 135, changing at the same time into camphoro-anhydridic acid, melt- 
 ing at 135 and boiling at 205 (12 mm.). The chloride of the latter is 
 converted by bromine into two isomeric bromo-camphoro-anhydridic 
 acid chlorides ; one of these, when boiled with water, forms the lactone 
 of unstable oxy-camphoronic acid, camphoranic acid, while the other, 
 under similar treatment, yields a stable oxy-camphoronic acid, melting 
 at 248. Camphoronic acid, upon distillation, breaks down into tri- 
 methyl-succinic anhydride, iso-butyric acid, CO 2 , H 2 O, and carbon. 
 
 Camphoranie acid C 9 H 12 O 4 +H 2 O, melting at 209, is a lactonic acid 
 which resists decomposition by alkalies very strongly. When fused 
 with caustic potash it is readily split into trimethyl-succinic acid and 
 oxalic acid (privately communicated by J. Bredt) : 
 
 CO O > COOH 
 
 (CH 3 ) 2 C C(CH 3 ) (COOH)CHCOOH (CH 3 ) 2 C CH(CH 3 )COOH 
 
 Camphoranic acid Trimethyl-succinic acid. 
 
 CH 2 CH C(CH 3 ) 2 
 
 Fenehone | CH 2 | (Ch. Ztg., 29, 1313), m.p. 6, b.p. 
 
 CH 2 C(CH 3 ).CO 
 
 193, D 19 , with specific gravity 0-9465 (19 mm.), n D = 1-46306, occurs 
 naturally in two isomeric modifications. Of all the known ketone 
 derivatives of terpenes this ketone is most like camphor in its behaviour. 
 
 VOL. II. 2 N 
 
546 ORGANIC CHEMISTRY 
 
 d-Fenehone was discovered in 1890 by Wallach and Hartmann in 
 fennel oil, while 1-fenehone was found in 1892 by Wallach, together with 
 pinene and thujone or tanacetone, in the oil of thuja. Potassium per- 
 manganate oxidises it to dimethyl-malonic acid, acetic acid, and oxalic 
 acid, while prolonged heating with concentrated acid oxidises it to 
 dimethyl-tricarballylic acid, dimethyl-malonic acid, and iso-camphoro- 
 nic acid (C. 1899, I. 285). On reduction, it reverses its optical rotation 
 and passes into d- and 1-fenchyl alcohol respectively, and fenchone 
 pinacone, m.p. 97. On heating with P 2 O 5 fenchone yields m-cymol, 
 probably with previous transposition ; under the action of strong 
 sulphuric acid it is transformed into acetyl-xylol CH 3 CO.C 6 H 3 [3, 4] 
 (CH 3 ) 2 (C. 1899, II. 1120). Fenchone does not combine with sodium 
 bisulphite or phenyl-hydrazin, and forms no oxy-methylene compound. 
 With sodium and CO 2 we obtain a- and jS-fencho-carboxylic acid C 10 H 17 O 
 (COOH), m.p. 142 and 77 respectively. These seem to be a-oxy- 
 acids (A. 300, 294). With bromine, fenchone, at 100, gives mono- 
 bromo-fenchone C 10 H 15 OBr, b.p. 18 I3i-i34 ; while with phosphorus 
 chloro-bromide, it yields tribromo-fenchane C 10 H 15 Br 3 (B. 33, 2287). 
 Fenchone oxime C 10 H 16 : NOH, m.p. 165 (active), 159 (inactive), b.p. 
 240. Fenchone semi-earbazone, m.p. 183 (active), 172 (inactive). 
 By heating with caustic potash to 230, or by the action of sodium 
 amide, fenchone, like camphor and camphenilone, is split up into 
 fencholic acid, i-methyl-^-iso-propyl-cyclo-pentane-i-carboxylic acid 
 CH 2 CH CH (CH 3 ) 2 
 
 CH 2 , m.p. 19, b.p. 17 152, which has also been ob- 
 
 CH 2 C(CH 3 )C0 2 H 
 
 tained synthetically (C. 1909, II. 212). Chloride, b.p. 15 100 ; amide, 
 m.p. 94 (A. 369, 71). a-Feneholenie acid C 9 H 15 COOH, liquid, b.p. 
 255, and j3-fencholenie acid C 9 H 15 .COOH, m.p. 73, b.p. 260, are 
 formed by saponifying their nitriles, a-nitrile, b.p. 212, j8-nitrile, b.p. 
 218, which are obtained together on boiling fenchone oxime with dilute 
 sulphuric acid (C. 1899, II. 115). They have not hitherto been changed 
 one into the other, and are therefore not mutually related like a- and 
 j3-campholenic acid. Both acids become lactones on treating with 
 concentrated sulphuric acid : oxy - dihydro - a - f encholenic lactone 
 C 10 H 18 O 2 , m.p. 78, and oxy-dihydro-j3-f encholenic lactone, m.p. 69 
 (B. 39, 2853), the latter being found also in the oxidation products 
 of fenchyl alcohol. A third isomeric acid C 9 H 15 COOH, y-fencholenic 
 acid, b.p. 10 146, easily passing into the a-form, is produced on heating 
 bromo-fenchone with alcoholic potash (B. 40, 432). 
 
 Iso-fenchone C 10 H 16 O, b.p. 201, is formed by oxidation of iso- 
 fenchyl alcohol with chromic acid. Oxime, m.p. 82 (active), 133 
 (inactive), easily substituted with bromine, forming monobrom-iso- 
 fenchone, m.p. 57. By heating with caustic potash it is split up into 
 iso-fencholic acid C 10 H 18 O 2 , m.p. 34 ; amide, m.p. 66. On oxidation 
 with KMnO 4 , a dicarboxylic acid is formed, iso-feneho-eamphoric acid 
 Ci H 16 O 4 , m.p. 159 (active), 175 (inactive) (A. 362, 194 ; 369, 97). 
 
 D. SESQUI-TERPENE AND POLY-TERPENE GROUP. 
 
 The sesqui-terpenes have the composition C 15 H 24 . They are re- 
 lated to the terpenes proper in a manner similar to the hemi-terpene 
 
SESQUI-TERPENE AND POLY-TERPENE GROUP 547 
 
 isoprene. The sesqui-terpenes are widespread among the ethereal oils. 
 Some 70 have been traced hitherto, but many of these may be identical. 
 They are slightly coloured, rather viscous oils, boiling between 250 and 
 280, of a feeble and rather unpleasant odour, and many of them re- 
 sinify easily, like the terpenes. On the basis of their molecular refrac- 
 tion, and other physical and chemical properties, we may distinguish 
 trebly unsaturated monocyclic, doubly unsaturated bicyclic, and singly 
 unsaturated tricyclic sesqui-terpenes. A probably aliphatic sesqui- 
 terpene has been found in Ceylon citronella oil (C. 1899, II. 880), but 
 completely saturated tetracyclic sesqui-terpenes are unknown. As 
 from the terpenes proper, so from the sesqui-terpenes, oxygenated 
 compounds of the composition C 15 H 24 O and C 15 H 26 O are derivable, 
 called sesqui-terpene alcohols, and sesqui-terpene camphors, which 
 are distinguished from the terpenes themselves by generally possessing 
 a great power of crystallisation. Practically nothing is known of the 
 constitution of the sesqui-terpenes. Many of them contain, perhaps, 
 hydrated naphthalin rings (B. 36, 1038). With halogen hydrides 
 NOC1, N 2 O 3 , and N 2 O 4 they sometimes form easily crystallising deriva- 
 tives, which may serve for their separation and characterisation. In 
 the following we enumerate some of the most important representa- 
 tives of this group. 
 
 Cadinene, b.p. 270, D 16 0-921 [O)D= 98-56, is found in many 
 ethereal oils, such as Oleum cadinum, cubebene oil, sandal-wood oil, 
 angostura bark oil (C. 1898, II. 666 ; 1900, 1. 858). 
 
 With HC1 it yields a dichlorohydrate, m.p. 118, from which, by 
 heating with aniline or sodium acetate, cadinene can be regenerated 
 (A. 238, 84 ; C. 1908, II. 1354). 
 
 Caryo-phyllene, b.p. 20 137, D 20 0-903, found in carnation and 
 copaiva oil. It probably consists of two isomeric hydrocarbons, the 
 optically inactive caro-phyllene found in hop oil (/. pr. Ch. 2, 83, 
 483), nitroso-chloride, m.p. 177, and the active jS-caryo-phyllene, 
 nitroso-chloride, m.p. 159 ; nitrosite, blue needles, m.p. 115 ; dichloro- 
 hydrate, m.p. 70 (C. 1899, II. 1119). By hydration with glacial acetic 
 acid and sulphuric acid we obtain earyo-phyllene hydrate C^H^O, 
 m.p. 95, from which, by elimination of water, a probably tricyclic 
 hydrocarbon isomeric with caryo-phyllene, clovene, is obtained (A. 271, 
 294 ; 369, 41 ; B. 42, 1062). 
 
 a-Santalene,b.p. 9 n8-i2o, D 20 0-8984, n D = 1-491, and /?-santalene, 
 b.p. 9 I25-I27, D 20 0-892, n D =i.4932, are contained in the first dis- 
 tillate of sandal-wood oil ; the former is probably a tricyclic, and the 
 latter a bicyclic, sesqui-terpene. On oxidation with ozone the a-santa- 
 lene yields tricyclo-ek-santalic acid C 11 H 16 O 2 , m.p. 68, and the j8- 
 santalene bicyclo-ek-santalic acid C U H 16 OH 2 , m.p. 64, also obtained 
 by disintegrating santalol (B. 40, 3321). 
 
 Zingiberene, b.p. 22 160, D 20 0-8731, n D = 1-49399, [a] D = 73-38, 
 is contained in ginger oil. Nitroso-chloride, m.p. 97 ; dichloro- 
 hydrate, m.p. 169 (C. 1901, II. 1226). 
 
 Galipene is the name of a dextro-rotatory sesqui-terpene obtained 
 from the oil of angostura bark, Galipea officinalis (C. 1898, II. 666). 
 
 Santalol C 15 H 24 O, b.p. 10 i6i-i68, D 20 0-973, forms the chief con- 
 stituent of the Indian sandal-wood oil from Santalum album. It prob- 
 ably consists of a mixture of two unsaturated primary alcohols, the 
 
548 ORGANIC CHEMISTRY 
 
 tricyclic a-santalol and the bicyclic jS-santalol. a-Santalol yields 
 on oxidation with KMn0 4 or ozone tri-cyclo-ek-santalic acid. Acids 
 convert a-santalol and its derivatives into isomeric, and, probably, 
 bicyclic compounds (B. 40, 1120). 
 
 Patchouli alcohol C 15 H 26 O, m.p. 56, separates out from patchouli 
 oil in crystals (A. 279, 394 ; C. 1904, 1. 1265). 
 
 Cedrol C 15 H 26 O, m.p. 87, [a] D =+9 31', from cedar-wood oil of 
 Juniper us virginiana. 
 
 The diterpenes C 20 H 32 and polyterpenes (C 5 H 8 )a. are yellow, viscid 
 oils, boiling above 300, volatilising with steam with some difficulty, 
 and therefore but rarely encountered in ethereal oils. They are found 
 in many balsams and resins. Their characterisation is rendered diffi- 
 cult by the fact that they only yield crystalline addition products with 
 difficulty. . 
 
 Addendum. Closely related to the polyterpenes is the cholesterin 
 already discussed in Vol. I., which, from its transformations, must be 
 regarded as a polycyclic secondary ring alcohol, with a vinyl and an 
 iso-amyl side chain. The constitution is complex, but is probably as 
 follows (B. 42, 3770) : 
 
 | 
 ) CH 2 
 
 /CH 2 CH 2 CH(CH 3 ) 2 
 
 \CH 
 
 CH(OH) CH 2 CH 2 
 
 RESINS. 
 
 The resins are closely related to the terpenes, and occur with them 
 in plants, and are also produced by their oxidation in the air. Their 
 natural, thick solutions in the essential oils and turpentines are called 
 balsams ; whereas the true gum resins are amorphous, mostly vitreous 
 bodies. Their solutions in alcohol, ether, or turpentine oils constitute 
 the commercial varnishes. 
 
 Most natural resins appear to consist of a mixture of different, 
 peculiar acids, the resin acids. The alkalies dissolve them, forming 
 resin soaps, from which acids again precipitate the resin acids. By their 
 fusion with alkalies we obtain different benzene derivatives (resorcinol, 
 phloro-glucin, proto-catechuic acid) ; and when they are distilled with 
 zinc dust they yield benzenes, naphthalenes, etc. 
 
 Colophony is found in turpentine and, in the distillation of the latter, 
 remains as a fused mass. It consists principally of abietic acid C ig ll 28 O 2 
 (sylvic acid), which can be extracted by hot alcohol, crystallises in 
 leaflets, and melts at 139 (147). When oxidised it yields trimellitic, 
 iso-phthalic, and terebic acids. 
 
 On heating with sulphur it turns into retene. It is therefore prob- 
 ably a decahydro-retene-carboxylic acid (C. 1904, II. 1308), and thus 
 is closely connected with fichtelite, a fossil resin, which has been recog- 
 nised as perhydro-retene. 
 
 Gallipot resin, from Pinus maritima, contains pimarie acid C 20 H 30 O 2 , 
 which is very similar to sylvic acid and passes into the latter when dis- 
 tilled in vacuo. It melts at 210. The latest investigations show that 
 pimarie acid consists of three isomerides (B. 19, 2167). 
 
 Gum lac, obtained from East India fig-trees, constitutes what is 
 
RESINS 549 
 
 known as shellac when fused. This is employed in the preparation of 
 sealing-wax and varnishes. 
 
 Amber is a fossil resin, found in peat-bogs. It consists of 
 succinic acid, two resin acids, and a volatile oil. After fusion it 
 dissolves easily in alcohol and turpentine oil, and serves for the 
 preparation of varnishes. 
 
 To the gum resins, occurring mixed with vegetables gums, and gum 
 in the juice of plants, belong gamboge, euphorbium, asafcetida, india- 
 rubber, and gutta-percha. 
 
 Caoutchouc, india-rubber, because of its wide applicability, is especi- 
 ally important. It has been obtained from tropical Euphorbiaceae, 
 Apocinaceae, etc. In Brazil it is made from Siphonia elastica, in India 
 from Ficus elastica, as well as other varieties of Ficus. Purified 
 caoutchouc has the formula (C 5 H 8 ) X . When distilled it yields isoprene 
 C 5 Hg (q.v.), which polymerises spontaneously to caoutchouc and also 
 to dipentene. 
 
 Caoutchouc is therefore probably a polymeric 1, 5-dimethyl-cyclo- 
 
 octadiene-1, 5 ~ - In accordance with its unsatu- 
 
 J x 
 
 rated nature, it easily absorbs oxygen, halogens, and nitrous-acid gas. 
 On prolonged treatment of a benzene solution of rubber with N 2 O 3 , 
 we obtain yellow crystalline nitrosite (C 10 H 15 N 3 O 7 ) 2 , decomposing at 
 i58-i62, the formation of which can be used for the quantitative 
 determination of rubber in mixtures. On distillation, india-rubber 
 yields, among hydrocarbons of greater molecular weight, isoprene 
 C 5 H 8 , which under various conditions, e.g. on simple heating in closed 
 vessels, partly polymerises again into rubber (B. 33, 779 ; 36, 1937 ; 
 A. 383, 184). 
 
 CH 3 C CH 2 .CH 2 .CH > CH 3 .C CH : CH 2 
 
 CH.CH 2 .CH 2 .CCH 3 ^~ CH 2 CH 2 : CH.C.CH 3 . 
 
 + 
 
 .C.( 
 
 This last reaction promises to be of great technical importance for 
 the artificial production of rubber. 
 
 India-rubber takes up sulphur when it is thoroughly kneaded with 
 it, or when it is treated with a mixture of S 2 C1 2 and CS 2 (B. 27, R. 204, 
 521, 601, 609, 701, 816 ; 29, R. 136). 
 
 The product is a vulcanised rubber, which continues elastic within 
 a considerable range of temperature. 
 
 Aromatic Hydrocarbons containing several Nuclei. 
 
 A. PHENYL-BENZOLS AND POLYPHENYL-FATTY HYDROCARBONS. 
 
 Just as alkyl groups are joined to one another, or as they are intro- 
 duced into benzene and its homologues, so the benzene hydrogen 
 atoms can be replaced by phenyl-, tolyl-, benzyl-, and other hydro- 
 carbon residues. The products are : (i) the phenyl-benzols, in which 
 the benzene nuclei are in immediate union : 
 
 C 6 H 5 .C 6 H 5 C 6 H 5 .C 6 H 4 CH 3 C 6 H 4 (C 6 H 5 ) 2 C 6 H 3 (CH 5 ) 3 
 
 Diphenyl Phenyl-tolyl Diphenyl-benzol Triphenyl-benzol. 
 
550 ORGANIC CHEMISTRY 
 
 (2) The polyphenyl paraffins, olefins and acetylenes, in which the 
 benzene residues are held together by fatty hydrocarbons : 
 
 C 6 H 6 , C 6 H 3 .CH 2 C 6 H 5 .CH C 6 H 5 .C 
 
 \CH 2 (C 6 H 5 ) 3 .CH (C 6 H 5 ) 4 C I || III etc. 
 
 C 6 H/ C.H..CH, C 6 H 5 .CH C 6 H 5 .C 
 
 Diphenyl- Triphenyl- Tetraphenyl- Dibenzyl Stilbene Tolane. 
 
 methane methane methane 
 
 In addition to these groups we have : B. The aromatic hydrocarbons 
 with condensed nuclei. 
 
 i. PHENYL-BENZOL GROUP. 
 
 i. A. Diphenyl Group. The first, or parent, hydrocarbon of this 
 group is diphenyl or phenyl-benzol. 
 
 Diphenyl, phenyl-benzol, biphenyl C 6 H 5 .C 6 H 5 , melting at 71 and 
 boiling at 254, is present in slight amount in coal-tar. It is formed 
 (i) upon conducting benzene vapours through tubes heated to redness 
 (Berthelot, Z./. Ch., 1866, 707 ; B. 9, 547 ; A. 230, 5) ; (2) in the action 
 of sodium upon the solution of bromo-benzol in ether or benzene 
 higher condensed hydrocarbons being produced at the same time 
 (Fittig, A. 121, 363 ; B. 29, 115) or, better, from iodo-benzol and 
 copper powder by heating to 230 (A. 332, 40) ; (3) from diazo-benzol 
 chloride (a) by action of benzene and aluminium chloride, (b) with 
 stannous chloride, (c) when alcohol and copper powder act upon diazo- 
 benzol sulphate, (d) from the latter salt and warm benzene (B. 23, 1226 ; 
 26, 1997). 
 
 If dissolved in glacial acetic acid, and oxidised with chromic 
 anhydride, it yields benzoic acid. Metallic sodium reduces diphenyl, 
 dissolved in amyl alcohol, to tetrahydro-diphenyl C 12 H 14 , boiling at 
 245. The latter readily forms a dibromide, which alcoholic potash 
 converts into dihydro-diphenyl C 12 H 12 , boiling at 248 (B. 21, 846). 
 A dihydro-diphenyl of m.p. 66 has been obtained from phenyl-dihydro- 
 resorcin by converting this diketone into the corresponding dihydric 
 alcohol, and removing two molecules of water from the latter, by means 
 of phosphorus pentoxide (A. 289, 168). Hexahydro-diphenyl, phenyl- 
 cyclo-hexane C 6 H 5 .C 6 H n , m.p. 7, b.p. 239, by synthesis from benzene 
 and chloro-cyclo-hexane or cyclo-hexyl chloride with A1C1 3 (C. 1907, I. 
 1745). Perhydro-diphenyl, dicyelo-hexyl C 6 H n .C 6 H n , b.p. 235, by 
 reduction of diphenyl with hydrogen and nickel under pressure (C. 1907, 
 II. 2036), or of cyclo-hexyl-cyclo-hexanol (see below) with HI, and, 
 synthetically, from iodo-cyclo-hexane and sodium (B. 40, 70). 
 
 Fluorene (B. 19, R. 672) is formed when methylene chloride and 
 aluminium chloride act upon diphenyl. 
 
 Alkylated diphenyls have been obtained : (i) By the action of 
 nitrous acid upon the alcoholic solution of their amido-compounds 
 (B. 17, 468 ; 21, 1096). (2) From the action of sodium upon the 
 brominated alkyl-benzols (B. 4, 396) ; this reaction gives by-products 
 in the shape of substances of the diphenyl-methane and dibenzyl series 
 (B. 4, 396 ; 32, 1056 ; 33, 334). (3) From iodo-alkyl-benzolene by 
 heating with powdered copper (A. 332, 38 ; C. 1910, I. 1974). (4) 
 From diphenyl, chloro-alkyl or ethylene, and aluminium chloride 
 (B. 20, R. 218). (5) From aromatic diazo-chlorides containing one 
 
PHENYL-BENZOL GROUP 551 
 
 nucleus. The position of the alkyl groups is determined by oxidation, 
 if it has not been made evident by the components : 
 
 m-Pheny\-to\yl,m-'methyl-diphenyl . b.p. 2 
 
 p-Phenyl-tolyl .... m.p. +3 263-267 (B. 26, 1996) 
 
 m-Ethyl-diphenyl ..... ,,283 
 
 J0 2 -Ditolyl ..... m.p. 17-8 258 
 
 m 2 -Ditolyl, m, m-dimethyl-diphenyl . 286 (B. 25, 1032) 
 
 o, m-Ditolyl ....... 286 
 
 p 2 -Ditolyl . . m.p. 122 -295 (A. 332, 44). 
 
 Hydrated derivatives of the diphenyl series are obtained syntheti- 
 cally by the method used in the case of the cyclo-hexenones (q.v.), e.g. 
 
 phenyl-methyl-cyclo-hexenone C 8 H 5 .CH< 2 ^ R CH, m.p. 36, is 
 
 formed from benzylidene-bis-aceto-acetic ester, and yields, on reduction, 
 phenyl-methyl-eyclo-hexanol C 6 H 5 .C 6 H 9 (CH 3 )(OH), b.p. 20 177, which, 
 on splitting off water, forms phenyl-methyl-cyclo-hexene C 6 H5.C 6 H 8 
 (CH 3 ), b.p. 17 129 (A. 303, 259). See also Phenyl-dihydro-resorcin. 
 
 Cyclo-hexyl-2-eyclo-hexanol C 6 H n .C 6 H 10 OH, m.p. 31, b.p. 270, 
 by reduction of cyclo-hexalidene-cyclo-hexanone (B. 40, 70). 
 
 Diphenyl Substitution Products. Each mono-substitution product 
 of diphenyl can exist theoretically in three isomeric forms. Chlorine, 
 bromine, the N0 2 group, and the sulpho-group prefer the p-position 
 with reference to the point of union of the two benzene residues, o- and 
 o, p-Derivatives are formed together with the p- and p 2 -derivatives. 
 The p 2 -derivatives, having two different substituents e.g. p-bromo- 
 p-nitro-diphenyl yield both p-bromo- and p-nitro-benzoic acids when 
 they are oxidised (see Benzidin). The amido-diphenylenes, particularly 
 benzidin, or p 2 -diamido-diphenyl and the diphenyl-sulphonic acids, 
 afford, as in the case of the corresponding benzene derivatives, numerous 
 derivatives of diphenyl. 
 
 It is interesting to note that o 2 -di-substitution products are known 
 in which a bivalent atom, O and S, or a bivalent group, NH, CH 2 , CO, 
 replaces two hydrogen atoms in the ortho-position with reference to 
 the point of union of the two benzene nuclei. 
 
 The principal representatives of such diphenylene compounds are : 
 
 eH 4 , C 6 H 4 . C 6 H 4V /C 6 H 4V \ /C 6 H 4 v \ 
 
 >0 | >S | \NH [I \CH 2 ) (I >CO 
 
 .H/ fc.H/ 6.H/ \C.H/ \C.H/ / 
 
 Diphenylene Diphenylene Carbazol Fluorene Fluorenone. 
 oxide sulphide 
 
 The first three will be treated in connection with the heterocyclic 
 derivatives after furfurane, thiophene, and pyrrol, from which they can 
 also be derived. They are formed by pyro-reactions from phenyl ether, 
 phenyl sulphide, and diphenyl-amine. 
 
 Halogen Diphenyls. o- and p-Chloro-diphenyl melt at 34 and boil 
 at 267, and at 75 and 282, respectively, o- and p-Bromo-diphenyls, 
 liquid, b.p. 310. p-Iodo-diphenyl, m.p. m. p 2 -Difluoro-, p 2 -dichloro-, 
 p 2 -dibromo-, and p 2 -di-iodo-diphenyl, m.p. 87, 148, 164, and 202 
 respectively (A. 207, 333 ; B. 30, 2800). 
 
 o 2 -Di-iodo-diphenyl, m.p. 108, with chlorine yields diphenyl- 
 
552 ORGANIC CHEMISTRY 
 
 di-iodide tetrachloride C1 2 IC 6 H 4 .C 6 H 4 IC1 2 , m.p. I3o-i35, from which 
 o 2 -di-iodoso and o 2 -di-iodo-phenyl are obtained. The latter, by the 
 action of potassium iodide, passes into diphenylene-iodonium iodide 
 
 C* H 
 
 * v >I.I, m.p. 211, also formed, besides o 2 -di-iodo-diphenyl, from 
 
 i > 
 
 C 6 H/ 
 
 the tetrazo-compound of o 2 -diamido-diphenyl, and is transposed on 
 heating into the isomeric o 2 -di-iodo-diphenyl (C. 1909, I. 374). On 
 derivatives of p 2 -di-iodo-diphenyl with multivalent iodine, see B. 
 42, 3826. 
 
 Perehloro-diphenyl C 12 C1 10 does not melt at 270. It is often pro- 
 duced in exhaustive chlorinations (B. 16, 2881). 
 
 Nitro-diphenyls. The nitration of diphenyl gives rise to o- and p- 
 nitro- as well as to p 2 - and o, p-dinitro-diphenyls. 
 
 Symmetrical di- and poly-nitro-diphenyls can be easily prepared 
 from o- and p-halogen-nitro-benzols and from m-iodo-nitro-benzols by 
 heating with copper powder (B. 34, 2174). They are also obtained by 
 the decomposition of diazoriium salts of nitranilines by means of 
 cuprous chloride or ammoniacal oxide solutions (B. 34, 3802 ; 38, 725 ; 
 A. 320, 123). 
 
 o 2 - and m 2 -Dinitro-diphenyls are obtained from benzidin (B. 
 20, 1028). 
 
 o-, m-, and p-Nitro-diphenyl, m.p. 37, 58, and 113. 
 
 2 -, m 2 -, p 2 -, and o, p-Dinitro-diphenyls melt at 124, 197, 233, 
 and 93. p 2 - and o, p-Dinitro-diphenyl have also been obtained from 
 sodium iso-diazo-nitro-benzene and nitro-benzene (B. 29, 165). 
 
 2 > P 2 -> and m 2> P 2 -Tetranitro-diphenyl, m.p. 163 and 186 respec- 
 tively, from i, 2, 4-chloro-dinitro- and i, 3, 4-iodo-dinitro-benzol 
 respectively with Cu dust. 
 
 2 , 2 , p 2 -Hexanitro-diphenyl, m.p. 238, from picryl chloride with 
 Cu dust. 
 
 p-Bromo-p-nitro-diphenyl, m.p. 173 (A. 174, 218). 
 
 p 2 -Dichloro-o 2 -dinitro-diphenyl, m.p. 136, from 2, 5-dichloro-nitro- 
 benzol or 4, 2-chloro-nitraniline. 
 
 The o 2 -dinitro-diphenyls are reduced by Na amalgam in alcohol, by 
 sodium sulphide and stannous chloride in HC1, or by electrolysis, in 
 such a manner that cyclic azoxy-compounds, phenazone oxides, and 
 further cyclic azo-compounds, phenazones, are formed (B. 37, 23). 
 These compounds are dealt with in detail in connection with ortho- 
 diazins (see Hetero-cyclic Compounds, Vol. III.) : 
 
 C 6 H 4 N0 2 C 6 H 4 N\ n C 6 H 4 N 
 
 C 6 H 4 N0 2 ~ * C 6 H 4 tt/* * C 6 H 4 N' 
 
 Amido-diphenyls and amido-ditolyls can be prepared by the reduc- 
 tion of the corresponding nitro-compounds. The formation of p 2 - 
 diamido-diphenyl by the rearrangement of its isomeride hydrazo- 
 benzol is of great technical importance, because p 2 -diamido-diphenyl 
 or benzidin is a basic substance for the preparation of substantive 
 cotton dyes dyes which unite directly with the cotton fibre without 
 the aid of mordants. 
 
 o-Amido-diphenyl, melting at 45, is also obtained from o-phenyl- 
 benzamide by means of bromine and caustic soda (A. 279, 266 ; B. 25, 
 
PHENYL-BENZOL GROUP 553 
 
 1974) . When conducted over heated lime it forms carbazol . m-Amido- 
 diphenyl, m.p. 30 (B. 37, 882). p-Amido-diphenyl, xenylamine, melts 
 at 51 and boils at 322 (A. 260, 233). p 2 -Nitro-amido-diphenyl, from 
 p 2 -dinitro-diphenyl, melts at 98. 
 
 o 2 -Diamido-diphenyl, m.p. 81, and m 2 -diamido-diphenyl have been 
 obtained by reducing o 2 - and m 2 -dmitro-diphenyl. When o 2 -diamido- 
 diphenyl is heated with concentrated sulphuric acid, it yields carbazol. 
 Its tetrazo-chloride is changed by potassium sulphydrate to carbazol, 
 and when its aqueous solution is heated, diphenylene oxide is produced 
 (B. 26, 1703). The reduction of the tetrazo-compound of o 2 -diamido- 
 
 C 6 H 4 [2]NHNH 2 
 diphenyl gives rise to diphenylene-o 2 -dihydrazin I , m.p. 
 
 GjH^fi'JNHNHj 
 
 110 (B. 29, 2270). When heated with hydrochloric acid at 150, it 
 breaks down easily into ammonium chloride and an o 2 -azo-diphenylene, 
 the so-called phenazone. 
 
 Benzidin, p^diamido-diphenyl, m.p. 122 (Zinin, 1845), is obtained 
 by the reduction of p 2 -dinitro-diphenyl and p 2 -nitro-amido-diphenyl. 
 It is commercially prepared by the reduction of azo-benzol in acid 
 solution ; the hydrazo-benzol, formed at first, rearranges itself to 
 benzidin and diphenyl, or o, p-oliamido-diphenyl. This is a remarkable 
 reaction, to which attention has already been called in connection with 
 hydrazo-benzol (A. 207, 330). 
 
 The great insolubility of the sulphate in water affords a means of 
 separating benzidin from diphenylin. When treated with concen- 
 trated sulphuric acid and nitric acid, one or two NO 2 groups enter in 
 the m-position with reference to the amido-groups of benzidin. The 
 products are o-nitro-p 2 -diamido-diphenyl and o 2 -dinitro-p 2 -diamido- 
 diphenyl (B. 23, 794). m 2 -Dinitro-p 2 -diacetamido-diphenyl results on 
 nitrating diaceto-benzidin. By chlorine and bromine the four H atoms 
 are replaced in the o-position towards the amido-groups (A. 363, 332). 
 By oxidation with lead peroxide in indifferent solvents, benzidin first 
 forms the unstable pp'-dipheno-quinone di-imines, and then the pp'- 
 diamido-azo-diphenyls (cp. the analogous transformation of o-phenyl- 
 ene-diamine into o 2 -diamido-azo-benzol) (B. 39, 3474). 
 
 Benzidin is, on the other hand, oxidised in acid solution by perman- 
 ganate, ferric chloride, potassium ferricyanide, or chromic acid, etc., to 
 a blue dye, probably belonging to the quino-hydrones, and built up in 
 a manner analogous to the Wurster salts (A. 363, 324 ; B. 41, 3248). 
 
 Constitution. The p-position of the two amido-groups of benzidin 
 (i) is evident from the oxidation of p 2 -bromo-mtro-diphenyl to p-bromo- 
 and p-nitro-benzoic acids (5, 6), because benzidin (i) is formed from 
 p 2 -dinitro-diphenyl (2), which may be rearranged to p 2 -amido-nitro- 
 diphenyl (3) and p 2 -bromo-nitro-diphenyl (4) (Gustav Schultz, A. 
 174, 227) : 
 
 (i) (2) ( 3 ) ( 4 ) C 6 H 4 [ 4 ]N0 2 
 
 C 6 H 4 [ 4 ]NH 2 C C H 4 [ 4 ]N0 2 C 6 H 4 [ 4 ]N0 2 C 6 H 4 [ 4 ]NO 2 ^CC^H 
 
 C 6 H 4 [ 4 ]NH, C C H 4 [ 4 ]N0 2 ~* C 6 H 4 [ 4 ]NH 2 ~* C G H 4 [ 4 ]Br ~1 CO 2 H 
 
 C 6 H 4 [ 4 ]Br 
 
 The constitution of benzidin forms the basis for one of the proofs 
 of the constitution of diphenic acid ; also for that of phenanthrene 
 isomeric with anthracene. 
 
554 ORGANIC CHEMISTRY 
 
 Benzidin sulphate consists of small scales with a silvery lustre ; 
 preparation, B. 26, R. 321. Concentrated sulphuric acid converts it 
 
 into benzidin-sulphone 632 > S 2 ( B - 22 2467). Diaceto-benzidin, 
 
 C 6 Jrl 3 (JNJrl 2 )/ 
 
 m.p. 317. Thionyl-benzidin (C 6 H 4 .N : S0) 2 (B. 24, 753). Di-(o-nitro- 
 benzyl-) benzidin, m.p. 227 with decomposition (B. 29, 1450). 
 
 o 2 -o' 2 -Tetrachloro- and tetrabromo-benzidin, m.p. 227 and 288. 
 
 o-Nitro-p 2 -diamido-diphenyl, m-nitro-benzidin, melts at 143 (B. 23, 
 796) ; see Benzidin. 
 
 NN-Dimethyl-benzidin CH 3 NHC 6 H 4 .C 6 H 4 NHCH 3 , m.p. 75, see 
 B. 37, 3771. On its behaviour towards oxidising agents, see B. 41, 3250. 
 
 Tetramethyl-benzidin (CH 3 ) 2 NC 6 H 4 .C 6 H 4 N(CH 3 ) 2 , m.p. 197, from 
 dimethyl-aniline by oxidation with concentrated sulphuric acid at 
 i9o-20o (B. 37, 29). NNi-Diphenyl-benzidin C 6 H 5 NHC 6 H 4 .C 6 H 4 
 NHC 6 H 5 , m.p. 242, is formed by the action of fuming sulphuric acid 
 upon diphenyl-amine (B. 38, 3575). 
 
 o 2 -Dinitro-p 2 -diamido-diphenyl, m-dinitro-benzidin, melts at 214 
 (B. 23, 795). o 2 -Dinitro-tetramethyl- and tetra-ethyl-benzidin, red 
 needles, m.p. 229 and 132 (B. 37, 29, 34). 
 
 3 2 -Dinitro-4 2 -diaceto-diamido-diphenyl melts above 300, and is 
 converted by caustic potash into 3 2 -dinitro-4 2 -diamido-diphenyl, 
 o-dinitro-benzidin, m.p. 220 (B. 5, 237 ; 20, 1024). 5 2 -Dinitro-2 2 - 
 diamido-diphenyl (B. 25, 128). 
 
 o, p'-Diamido-diphenyl, diphenylin, melts at 45 and boils at 362. 
 Preparation, see Benzidin (A. 207, 348 ; B. 22, 3011). o, p 2 -Triamido- 
 diphenyl, m-amido-benzidin (B. 23, 797). o 2 , p 2 -Tetramido-diphenyl, 
 m^-diamido-benzidin, melting at 165, is obtained from o 2 -dinitro-p 2 - 
 diamido-diphenyl (see Benzidin), and by loss of ammonia becomes 
 p 2 -diamido-carbazol. 
 
 Di-p-phenylene-diamine (NH 2 ) 2 [2, 5]C 6 H 3 .C 6 H 3 [2, 5](NH 2 ) 2 , melting 
 at 168, is converted by hydrochloric acid at 180 into 5 2 -diamido- 
 carbazol (B. 25, 131). 
 
 Diamido-dixenylamine NH(C 6 H 4 .C 6 H 4 .NH 2 ) 2 , m.p. 221, is obtained 
 by heating benzidin with benzidin chloride (/. pr. Ch. 2, 61, 103). 
 
 Benzidin Homologues. p 2 -Diamido-phenyl-m-tolyl, o-methyl-benzi- 
 din H 2 N.C 6 H 4 .C 6 H 3 (CH 3 ).NH 2 , is formed upon reducing a mixture of 
 nitro-benzol and o-nitro-toluol. It melts at 90 (B. 23, 3222). 
 
 o-Tolidin, p 2 -diamido-m 2 -dimethyl-diphenyl, from o-hydrazo-toluol, 
 melts at 128 (B. 20, 2017 ; 23, 3252 ; A. 352, in). 
 
 m-Tolidin, p 2 -diamido-o 2 -dimethyl-diphenyl, from m-hydrazo-toluol, 
 melts at 109. Isomeric ditolylin (B. 23, 3252) is produced at the 
 same time. 
 
 o- and m-Hydrazo-toluols suffer under the influence of acids the 
 benzidin rearrangement. p-Hydrazo-toluol, under like conditions, 
 follows the semidin rearrangement. 
 
 p 2 -Diamido-m 2 -diethyl-diphenyl, from o-nitro-ethyl-benzol (/. pr. 
 Ch. 2, 66, 153). 
 
 Diazo-amido- and Azo-compounds of Diphenyl. The diphenyl- 
 tetrazo-chloride, formed by diazotation of benzidin in hydrochloric 
 solution, unites with two molecules aniline to form : 
 
 Diphenyl - bis - diazo - amido - benzol C 6 H 5 NH.N : NC 6 H 4 .C 6 H 4 N : 
 NNC 6 H 5 , reddish-yellow crystals, m.p. 180, also obtained from benzidin 
 
PHENYL-BENZOL GROUP 555 
 
 and diazo-benzol chloride. On heating with aniline and its chloro 
 hydrate it transposes into the isomeric diphenyl-diazo-amido-benzol 
 NH 2 C 6 H 4 N : NC 6 H 4 .C 6 H 4 N : NC 6 H 4 NH 3 , m.p. 159 (C. 1906, I. 1254). 
 
 pp'-Diamido-azo-biphenyl NH 2 [4]C 6 H 4 .C 6 H 4 N : NC 6 H 4 .C 6 H 4 [ 4 ]NH 2 , 
 m.p. 287, is formed by oxidising benzidin with PbO 2 , and from pp'- 
 amido-nitro-diphenyl by reduction with zinc dust and NaOH, and 
 oxidation of the resultant hydrazo-compound (B. 39, 3479). 
 
 Benzidin Dyes. Benzidin yields azo-dyes, transposition products of 
 the diazo-chloride from benzidin and amido-sulphonic acids, phenol- 
 carboxylic acids, and phenol-sulphonic acids, which unite directly with 
 cotton fibre (Griess, B. 22, 2469). These dyes are obtained as sodium 
 salts, which are prepared by adding the aqueous solution of the tetrazo- 
 chloride to the aqueous solution of two molecules of the sodium salt 
 of the other component. 
 
 Sodium acetate, sodium carbonate, or ammonia is added to the 
 solution of the sodium salt to neutralise the hydrochloric acid which 
 is liberated : 
 
 C.H.N.-Cl C.H^OHJCOjNa C.H 4 N : N.C.H,(OH).CO,Na 
 
 + I +CO,Na.= | + 2NaCl+CO.+H.O. 
 
 C.H 4 N,.C1 C.H 4 (OH)CO,Na CH 4 N : N.CH s (OH).CO,Na 
 
 The diphenyl-tetrazo-chloride, which can also be readily formed 
 in the solid state, reacts more readily with one of its diazo-groups than 
 it does with the other (cp. B. 30, 2800 ; 31, 482). 
 
 The sodium salts of two different components can thus be, step by 
 step, brought into reaction with the tetrazo-chloride, and mixed tetrazo- 
 dyes (B. 19, 1697, 1755 ; 20, R. 273 ; 21, R. 71) result. 
 
 Representatives of the class of benzidin dyes are : 
 
 C 6 H 4 .N : N.C 6 H 3 (OH).C0 2 Na 
 
 Chrysamme, flavo-phemn , which is made 
 
 C 6 H 4 .N : N.C.H 3 (OH).C0 2 Na 
 
 from diphenyl-tetrazo-chloride and sodium salicylate (equation above) 
 (B. 22, 2459). 
 
 C,H 4 .N : N.C 6 H 3 (NH 2 ).S03Na 
 Congo yellow I is obtained from diphenyl- 
 
 C 6 H 4 .N : N.C 8 H 4 .OH 
 tetrazo-chloride, phenol, and sulphanilic acid. 
 
 The preceding dyes colour cotton fibre yellow. 
 
 The first red dye brought into commerce was Congo red, which is 
 formed from the interaction of diphenyl-tetrazo-chloride and sodium 
 naphthionate. It will be brought forward again under the naphthalene 
 azo-dyes. The jS-naphthyl-amine-sulphonic acids are particularly valu- 
 able in the preparation of substantive dyes. 
 
 Substantive dyes, similar to those from benzidin, have been obtained 
 from p 2 -amido-methyl-diphenyl, o-methyl-benzidin, o- and m-tolidins, 
 dianisidin, thio-benzidin, thio-tolidin (B. 20, R. 272), p 2 -diamido-benzo- 
 phenone, p 2 -diamido-stilbene (B. 21, R. 383). 
 
 It may be said that, as a rule, those substituted, benzidins (nitro- and 
 sulpho-benzidins, tolidins, etc.) having the substituent in the meta- 
 position (relative to the amido-group) yield inactive or feeble substantive 
 azo-dyes. Diamido-diphenylene oxide, benzidin sulphone, and diamido- 
 carbazol constitute exceptions. They contain a third ring-shaped chain 
 (B. 23, 3252, 3268 ; 24, 1958). 
 
 It is interesting to observe that benzidin hydrochloride itself unites 
 
556 ORGANIC CHEMISTRY 
 
 with cotton. It mordants the cotton. Hence it is possible to produce 
 the benzidin upon the fibre (B. 19, 2014). 
 
 The " one-sided diazotising " of benzidin is attained through the 
 action of a p-tetrazo-diphenyl salt upon the aqueous solution of a 
 benzidin salt (B. 27, 2627) ; compare migrations of the diazo-group. 
 When the bis-diazo-compound of benzidin is allowed to act upon 
 aceto-acetic ester there result, with one molecule of the ester, eyclo- 
 
 .N.NH C 6 H 4 
 
 formazyl-carboxylie ester COOC 2 H 5 c^ , a reddish-brown 
 
 \N : N C 6 H 4 
 
 powder, fusing with difficulty (see Formazyl-carboxylie acid) ; and, 
 with two molecules of the ester, bis-aeetyl-glyoxylie ester-phenyl- 
 hydrazone [CH 3 COC(CO 2 C 2 H 5 ) : NNHC 6 H 4 ] 2 , yellow needles, melting 
 at 198 (A. 295, 332 ; cp. C. 1899, I. 563). Similar compounds with 
 malonic and cyano-acetic ester, see C. 1902, I. 721, 1205. 
 
 p-Hydrazino-diphenyl C 6 H 5 .C 6 H 4 [4]NH.NH 2 (B. 27, 3105). p 2 -Di- 
 hydrazino-diphenyl (C 6 H 4 .NHNH 2 ) 2 , m.p. 167 with decomposition, 
 yields, with formaldehyde, a characteristic hydrazone (B. 32, 1961) ; 
 see also Diphenylene-o 2 -dihydrazin. 
 
 Biphenyl-sulphonic Acids. On digesting biphenyl with sulphuric 
 acid the first product is biphenyl-p-sulphonie acid (its chloride melting 
 at 115, and its amide at 229), and, later, biphenyl-p 2 -disulphonic acid, 
 melting at 72, and its chloride at 203 (B. 13, 288). When potassium- 
 biphenyl-p-sulphonate is heated it changes to biphenyl and potassium- 
 biphenyl-p 2 -disulphonate. 
 
 Biphenyl-p 2 -disulphonic acid is obtained from benzidin-o 2 -di- 
 sulphonic acid (A. 261, 310). 
 
 C 6 H 4 [2]NH 
 
 Biphenylene sultame I | , m.p. 196, in colourless crystals of 
 
 C 6 H 4 [2]S0 2 
 
 strongly acid character. Formed from the diazo-compound of 
 o-amido-benzol sulphanilide on heating in acid solution (B. 43, 2694). 
 
 Benzidin-sulphonic A cids. 4 2 -Diamido-biphenyl-2 2 -disulphonic acid 
 is formed from m-hydrazo-benzol-sulphonic acid (A. 261, 310 ; 268, 
 X 3 i / P*> Ch. 2, 66, 558), and, when fused with caustic potash, yields 
 4 2 -diamido-diphenylene oxide. 
 
 4 2 -Diamido-biphenyl-3 2 -disulphonic acid is produced on heating 
 benzidin with ordinary sulphuric acid to 210 (B. 22, 2466 ; 39, 3341). 
 
 o-Tolidin-disulphonie acid, ^-diamido-^ ^-dimethyl-biphenyl-2 2 -disul- 
 phonic acid (A. 270, 359). 
 
 4 2 -Dihydrazino-biphenyl-2 2 -disulphonic acid (c 6 H 3 <(?"! H 3 \ see A. 
 
 V ^^^3-n-/2 
 
 261, 323. 
 
 Oxy-biphenyls are obtained from the biphenyl derivatives by 
 methods similar to those by which the phenols themselves are prepared 
 from the benzene derivatives, and also in the oxidation of phenols con- 
 taining a single nucleus, when they are fused with caustic potash 
 (B. 27, 2107). 
 
 Monoxy-biphenyls. p-Oxy-biphenyl C 6 H 5 .C 6 H 4 [4]OH, m.p. 165 
 and b.p. 306, is obtained from diazo-benzol chloride and phenol 
 (B. 23,3708). 
 
 Dioxy-biphenyls. o 2 -Dioxy-biphenyl, o 2 -biphenol, m.p. 109, b.p. 
 326, from biphenyl-o 2 -disulphonic acid (A. 261, 332) and from 
 
PHENYL-BENZOL GROUP 557 
 
 diphenylene oxide (coal-tar) by fusing with potash (B. 34, 1662). 
 By fusing with zinc chloride it reverts clearly into diphenylene oxide. 
 Its dimethyl ether, m.p. 155, b.p. 308, is also formed from o-iodanisol 
 with sodium or copper dust. Ethylene bromide gives an ethylene 
 ether, m.p. 98 (B. 35,302). 
 
 m-Biphenol, m.p. I23-I25, is obtained from o-dianisidin and 
 m 2 -diamido-triphenyl (B. 27, 2107). p 2 -Biphenol, m.p. 272, is pre- 
 pared from benzidin, biphenyl-p 2 -disulphonic acid, and from phenol 
 by the action of KMnO 4 (B. 25, R. 335) . o, p-Biphenol, from diphenylin, 
 melts at 160. 2, 5-Dioxy-diphenyl, phenyl-benzo-hydroquinone 
 (HO) 2 [2, 5].C 6 H 3 C 6 H 5 , m.p. 97, is formed by reduction of phenyl- 
 benzo-quinone (see below) ; and mamVtetramethyl-p^dioxy-diphenol 
 OH[ 4 ](CH 3 ) 2 [3, 3']C 6 H 2 .C 6 H 2 [ 3 , 3 / ](CH 3 ) 2 [4]OH, m.p. 221, from 
 tetramethyl-dipheno-quinone (see below). 
 
 Tetra-oxy-biphenyls. Bipyro-eatechin (HO) 2 C 6 H 3 .C 6 H 3 (OH) 2 , m.p. 
 84, biresorcin, melting at 310, and bihydroquinone, m.p. 237, result 
 when the three dioxy-benzols are fused with sodium hydroxide (B. 
 11, 1336 ; 12, 503 ; 18, R. 23). 
 
 Hexa-oxy-biphenyls. Hexa-oxy-biphenyl (HO) 3 C 6 H 2 .C 6 H 2 (OH) 3 is 
 formed from pyrogallol in baryta solution by oxidation in air (B. 35, 
 2954). An isomeric hexa-oxy-biphenyl has been obtained from its 
 tetramethyl ether, hydro-ccerulignone C 16 H 18 O 6 , m.p. 190, by heating 
 with concentrated HC1 (B. 11, 797). 3, 4, 5, 3', 4', 5'-hexamethoxy- 
 biphenyl, m.p. 126, and 2, 3, 4, 2', 3', 4 / -hexamethoxy-biphenyI, m.p. 
 123, is obtained from 5- and 4-iodo-pyrogaUol-trimethyl ether with 
 copper dust (A. 340, 230). 
 
 Amido-oxy-biphenyls are obtained from oxy-biphenyls (B. 22, 335) 
 and from the alkyl ethers of oxy-azo-derivatives, having free p-positions, 
 by the benzidin rearrangement (B. 23, 3256). In the coal-tar industry 
 o-dianisidin or 4 2 -diamido-3 2 -dimethoxy-biphenyl and ethoxy-benzidin, 
 from o-nitro-anisol, are of great value. They yield violet, blue, and 
 black substantive cotton dyes with amido-naphthalene-sulphonic 
 acid, naphthol-sulphonic acid, and amido-naphthol-sulphonic acids : 
 azo-violet, benzazurin, diamine black, etc. (B. 22, R. 372 ; 24, R. 55, 
 56, etc.). 
 
 2, 5-Amido-oxy-diphenyl C 6 H 5 .C 6 H 3 [2, 5](OH)(NH 2 ), m.p. 199, is 
 obtained by reduction of 2, 5-nitroso-oxy-diphenyl C 6 H 5 .C 6 H 3 [2, 5] 
 (OH) (NO), generated by the action of diazo-benzol chloride upon 
 p-nitroso-phenate of sodium. The latter, on oxidation, passes into 
 2, 5-nitro-oxy-diphenyl, m.p. 126, also obtained synthetically from 
 benzyl-methyl-ketone C 6 H 5 CH 2 COCH 3 and nitro-malonic aldehyde 
 NO 2 CH(CHO) 2 (C. 1905, I. 505). 
 
 Quinones of the Diphenyl Series. Phenyl-benzo-quinone CgHg. 
 C 6 H 3 O 2 , m.p. 114, has been obtained by the oxidation of 2, 5-amido- 
 oxy-diphenyl, or of o-amido-diphenyl with MnO 2 and sulphuric acid. 
 With sulphurous acid it gives a stable quinhydrone, also formed by 
 oxidation in air from the 2, 5-dioxy-diphenyl produced with stronger 
 reducing agents (A. 312, 211 ; B. 37, 878). 
 
 Special interest attaches to a number of quinone compounds of 
 diphenyl, in which the two quinone oxygen atoms belong to different 
 benzene rings. Regarding the quinones as carboxyl compounds, the 
 following three fundamental forms of these so-called bi-nuclear 
 
558 ORGANIC CHEMISTRY 
 
 quinones are possible, and may be distinguished as pp'-, op'-, and 
 oo'-dipheno-quinones : 
 
 /CH=CH\ . /CH=CH\ /CH-CO\ . C < /CH=CH \CO 
 
 C \CH=CH/ C ' C \CH=CH/ C l \CH=CH/ C ' C \CH=CH/ ( 
 
 /CH-CO\ . /C- 
 i \CH^CH/ C ' C \CH=CH 
 
 Of these, only the pp'-dipheno-quinone could hitherto be prepared 
 in the free state, but nitrogenated derivatives (quinone chlorimines) of 
 the other two forms are known (A. 368, 271). 
 
 pp'-Dipheno-quinone O : C 6 H 3 : C 6 H 3 : O, decomposing at 165, is 
 formed by the oxidation of p-diphenol with silver oxide or lead per- 
 oxide in benzene. It crystallises in two modifications, hard spears 
 resembling chromic acid, and fine, soft needles. In its oxidising action 
 it resembles p-benzo-quinone, but in contrast with this it is odourless 
 and not volatile. It can be reduced to p-diphenol, with which it 
 unites in molecular ratio to form dipheno-quin-hydrone, dark-green 
 needles decomposing at 180 (B. 38, 1232). 
 
 m 2 , m' 2 -Tetramethyl-p, p'-dipheno-quinone O : C 6 H 2 (CH 3 ) 2 : C 6 H 2 
 (CH 3 ) 2 : O, m.p. about 210, red needles, formed by the oxidation of 
 vic-m-xylenol with chromic acid. It yields, on reduction, tetramethyl- 
 dioxy-biphenyl, with which it forms a quin-hydrone, m.p. 201, steel- 
 blue flakes (B. 38,226). 
 
 Tetrachloro- and tetrabromo-pp'-dipheno-quinone have been ob- 
 tained by the oxidation of the corresponding p-diphenol derivatives 
 with fuming HNO 3 in glacial acetic acid. They form infusible deep- 
 red crystals with blue surface colour, which revert to the original 
 substances under the action of sulphurous acid (B. 13, 224). 
 
 Coerulignone or cedriret must be regarded as a tetramethoxy-pp'- 
 dipheno-quinone. 
 
 It separates as a violet powder when crude wood-spirit is purified 
 on a large scale by means of potassium chromate. It is further formed 
 on oxidising dimethyl-pyrogallol from beech-wood tar with potassium 
 chromate or ferric chloride : 
 
 OCH 3 H 2H QCH 3 H . H OCH 3 
 
 1 OCH 3 H ' OCH 3 H ' H OCH 3 ' ' 
 
 Coerulignone is insoluble in the ordinary solvents, and is precipi- 
 tated in fine, steel-blue needles, from its phenol solution, by alcohol or 
 ether. It dissolves in concentrated sulphuric acid with a beautiful 
 blue colour. Large quantities of water colour the solution red at first. 
 Reducing agents (tin and hydrochloric acid) convert ccerulignone into 
 colourless hydro-ccerulignone, which changes again to the first by 
 oxidation. Ccerulignone is, therefore, a quinone body, and may be 
 called a binuclear quinone. 
 
 It unites with primary aromatic amines, forming blue dyes. It is 
 very probable that in doing this two methoxyl groups are replaced by 
 amino-residues (B. 30, 235). 
 
 On the action of alcoholic HC1 upon ccerulignone, see B. 31, 615 ', 
 cp. also A. 368, 276. 
 
 A derivative of pp'-dipheno-quinone is probably also the so-called 
 tribromo-reso-quinone, m.p. 214, obtained from pentabromo-resorcin 
 
PHENYL-BENZOL GROUP 559 
 
 by heating, or by treatment with silver nitrate solution, with elimina- 
 tion of two bromine atoms (B. 42, 2814). 
 
 Aldehydes and Ketones of the Diphenyl Series. o-Phenyl-benzalde- 
 hyde C 6 H 5 .C 6 H 4 [2]CHO, b.p. 21 184, is formed by the distillation of 
 calcium-o-phenyl-benzoate with calcium formate. p-Phenyl-benzalde- 
 hyde, m.p. 57, b.p. 184, has been obtained from diphenyl-glyoxylic 
 acid C 6 H 5 C 6 H 4 CO.COOH, m.p. 170, whose ester is obtained by the 
 condensation of diphenyl and ethoxalyl chloride by means of A1C1 3 
 (C. 1897, II. 799; 1899, I. 424). 4, 4'-Diphenyl-dialdehyde CHO[4] 
 C 6 H 4 .C 6 H 4 [4]CHO, m.p. 145 ; its dianile is formed by heating p-iodo- 
 benzylidene-aniline with copper dust (A. 332, 76). 
 
 m-Phenyl-acto-phenone C 6 H 5 .C 6 H 4 [3]COCH 3 , m.p. 121, from 
 diphenyl, acetyl chloride, and A1C1 3 (/. pr. Ch. 2, 81, 394). Nitro- 
 phenyl-benzaldehyde NO 2 G 6 H 4 .C 6 H 4 CHO and nitro-phenyl-aceto- 
 phenone NO 2 C 6 H 4 .C 6 H 4 COCH 3 are formed from sodium iso-diazo- 
 nitro-benzate, with benzaldehyde and aceto-phenone respectively, in 
 the presence of acetyl chloride (B. 28, 525). oo'-Diaeetyl-diphenyl 
 CH 3 CO[2]C 6 H 4 .C 6 H 4 [2]COCH 3 , m.p. 84, see A. 363, 305. 
 
 Biphenyl-carboxylic acids are obtained from diphenyl derivatives 
 by reactions similar to those by which the benzene-carboxylic acids are 
 prepared from the derivatives of benzene. 
 
 Biphenyl-mo no carboxylic Acids. There are three possible acids : 
 o-Phenyl-benzoie acid C 6 H 5 .C 6 H 4 [2]CO 2 H, melting at m, is produced 
 by fusing diphenylene-ketone with caustic potash (A. 166, 374) ; by 
 the distillation of sodium salicylate with triphenyl-phosphate (/. pr. 
 Ch. 2, 28, 305) ; and from o-amido- and o-methyl-diphenyl. If the 
 acid be treated with PC1 5 , or if it be heated with sulphuric acid to 
 100, or with lime to more elevated temperatures, diphenylene-ketone 
 will be formed (A. 266, 142 ; 279, 259). 
 
 o-Phenyl-hexamethylene - carboxylic acid C 6 H 5 [i]C 6 H 10 [2]COOH, 
 m.p. 150, is synthesised from phenyl-pentamethylene dibromide with 
 sodium-malonic ester, etc. (B. 35, 2122). 
 
 m-Phenyl-benzoic acid, melting at 160, results from the oxidation 
 of m-methyl-biphenyl, of iso-diphenyl-benzol, and in the reduction of 
 bromo-m-phenyl-benzoic acid (B. 27, 3390). 
 
 p-Phenyl-benzoic acid, melting at 218, is obtained from p-methyl- 
 biphenyl, from p-diphenyl-benzol, from sodium biphenyl-sulphonate 
 (A. 282, 143), from p-amido-diphenyl, and by fusing benzoic acid with 
 caustic potash. It is reduced to p-phenyl-hexahydro-benzoic acid 
 C 6 H 5 C 6 H 10 [4]CO 2 H, in two modifications melting at 202 and 113 
 respectively (A. 282, 139). p 2 -Nitro-phenyl-benzoic acid, melting at 
 222-225, results from the oxidation of p 2 -nitro-phenyl-tolyl. It yields 
 the corresponding amido-acid (B. 29, 166) on reduction. 
 
 Biphenyl-m-acetic acid C 6 H 5 .C 6 H 4 [3]CH 2 COOH, m.p. 153, from 
 m-phenyl-aceto-phenone (see above), by heating with yellow ammonium 
 sulphide. 
 
 Oxy- bipheny I -carboxylic Acids. The following acids are all 
 derivatives of o-phenyl-benzoic-acid : 
 
 6-Phenyl-salicylie acid C 6 H 5 [6]C 6 H 3 [2](OH)CO 2 H, melting at 159, 
 results upon fusing 3-oxy-diphenylene-ketone and potassium hydroxide 
 (B. 28, 112). 
 
 2-Phenyl-m-oxy-benzoie acid C 6 H 5 [2]C 6 H 3 [3]OH.CO 2 H, melting at 
 
560 ORGANIC CHEMISTRY 
 
 154, is obtained as the principal product in the fusion of 6-oxy- 
 diphenylene-ketone with potassium hydroxide (A. 284, 307). 
 
 o-Oxy-phenyl-o-benzoic acid is only known in the form of its 
 
 lactone, biphenyl-methylolid | | , melting at 92-5, which is 
 
 C 6 H 4 [2]0 
 
 formed as a by-product on fusing 6-oxy-diphenylene-ketone or o-oxy- 
 fluorenone with caustic potash, in small quantities by the action of 
 POC1 3 upon sodium salicylate, and when phenol acts upon the sulphate 
 of o-diazo-benzene (A. 284, 316). It corresponds in composition to 
 
 C a H 4 [2]CO 
 phenanthridone \ \ , melting at 203 (see this), which is pro- 
 
 duced when bromine and caustic potash act upon diphenamic acid 
 (A. 276, 245). 
 
 p-Oxy-phenyl-o-benzoic acid HO[4]C 6 H 4 [i]C 6 H 4 [2]C0 2 H, melting 
 at 206, is produced, together with biphenyl-methylolid and phenyl- 
 ether-salicylic acid, by the action of phenol upon the sulphate of 
 o-diazo-benzoic acid (A. 286, 323). 
 
 Biphenyl-dicarboxylic acids contain the two C0 2 H groups, either 
 linked to the same or to different benzene residues. Diphenic acid is 
 the most important biphenyl-dicarboxylic acid. 
 
 Phenyl-iso-phthalic acid C 6 H 5 C 6 H 3 [3, 5](COOH) 2 melts above 310, 
 and is formed on boiling benzaldehyde and pyro-racemic acid with 
 baryta water (B. 24, 1750). 
 
 Diphenic acid, o 2 -biphenyl-dicarboxylic acid CO 2 H[2]C 6 H 4 .C 6 H 4 [2] 
 CO 2 H melts at 229. 
 
 It is formed from diazo-anthranilic acid by the action of ammoniacal 
 cuprous oxide solution (A. 320, 123). Its dimethyl ester, m.p. 74, 
 forms on heating o-iodo-benzoic ester with copper (A. 332, 70). 
 
 It is produced in the oxidation of phenanthraquinone with a 
 chromic acid mixture, or by boiling it with alcoholic potash. The 
 constitution of phenanthrene follows from it. That of diphenic 
 acid (2) is evident from its oxidation to o-phthalic acid (i) (Anschiitz 
 and Japp, B. 11, 211) by potassium permanganate, and its formation 
 by the deamidation of p 2 -diamido-diphenyl-o 2 -dicar boxy lie acid (3), 
 which is obtained on the one hand from p 2 -dinitro-diphenic acid 
 
 (4) , and on the other by the rearrangement of m-hydrazo-benzoic acid 
 
 (5) (G. Schultz, A. 204, 95) : 
 
 C,H,[ 
 
 ( *>JU]NO, j'VjNH, ^[ 3 ]C.H,CO,H 
 
 C,H 4 [2]CO a H C 6 H 4 [2]CO a H ^ ( [ 2 ]CO a H C 6 H 3 \ [2]CO 2 H 
 
 CO a H 
 
 C 8 H 4 [2]CH 
 
 [2]C0 2 H A( J H r [ 2 ]C0 2 H C I H_/!X!CP,H NH[3]C,H 4 CO 2 H 
 
 (6) 
 
 CACaKO ^ Y 3 ^ ^ co C 6 H 4 [ 4 ]NH a Y 
 
 C 6 H 4 [2]CH ~C.H 4 [2]CO "^^^ /[2]CO C.H 4 [ 4 ]NH a ^ 
 
 In this circle of reactions there should also be included the formation 
 of p 2 -dinitro-diphenic acid by the oxidation of p 2 -dinitro-phenanthra- 
 quinone (6) and the transposition of diamido-diphenic acid to benzidin 
 (7), the constitution of which was previously deduced, and to p 2 - 
 diamido-fluorene (8). 
 
PHENYL-BENZOL GROUP 561 
 
 Concentrated sulphuric acid changes diphenic acid to diphenylene- 
 ketone-car boxy lie acid. When it is digested with acetyl chloride or 
 
 C 6 H 4 .C(X 
 acetic anhydride it yields diphenic anhydride I ^>O, melting at 
 
 213 (A. 226, i). This is a remarkable compound, inasmuch as it can 
 be viewed as adipinic anhydride and contains a " seven-membered " 
 
 C 6 H 4 .COC1 
 ring. Diphenic chloride I , melting at 93, is reduced in 
 
 ethereal solution by zinc and hydrochloric acid to phenanthrene-hydro- 
 C 6 H 4 .C(OH) C 6 H 4 .CO.NH 2 
 
 quinone I (A. 247, 268). Diphenamino acid I 
 
 C 6 H 4 .C(OH) C 8 H 4 .CO.OH 
 
 melting at 193 , is converted by a hypobromite or hypochlorite, in 
 alkaline solution, into phenanthridone (A. 276, 248). Diphenimide 
 C fl H 4 .CO x 
 
 >NH, melts at 219 (A. 247, 271). 
 C 6 H 4 .C(X 
 
 o-, m-, and p-Nitro-diphenic acid, m.p. 248-25o with decomposition, 
 268, and 2i4-2i6 respectively, 2 - and p 2 -dinitro-diphenic acid, m.p. 
 303 with decomposition, and 253 respectively, are formed from the 
 nitro- and dinitro-phenanthrene-quinones by oxidation with chromic 
 acid mixture ; in the o 2 - and p 2 -dinitro-acid the anhydride formation 
 is more difficult (B. 36, 3730, 3738). The ester of the p 2 -acid is also 
 obtained from two molecules of 2-bromo-5-nitro-benzoic ester, by 
 heating with copper dust. In the same manner, o 2 -dinitro-biphenyl- 
 p 2 -dicarboxylie ester is obtained from 4-bromo-3-nitro-benzoic ester 
 (B. 34, 2682). By reduction, the nitrated diphenic acids yield amido- 
 and diamido-diphenic acids, from which amido-oxy- and dioxy- 
 diphenic acids are obtained (B. 38, 3769). 
 
 Hexa-oxy-biphenyl-o 2 -dicarboxylic acid. The formula of a dilactone 
 
 of this acid g]c3: SSSp P robabl y a PP Ues to eUa ic acid 
 (q.v.), the oxidation product of gallic acid (B. 36, 212). 
 
 Iso-diphenie acid (o, m') CO 2 H[3]C 6 H 4 .C 6 H 4 [2]CO 2 H, melting at 
 216, is produced when diphenylene-ketone-carboxylic acid is fused 
 with caustic potash. 
 
 o, p'-Biphenyl-dicarboxylie acid CO 2 H[4]C 6 H 4 .C 6 H 4 [2]CO 2 H, melting 
 at 251, is obtained from diphenylin (B. 22, 3019). 
 
 m 2 -Biphenyl-dicarboxylic acid, m.p. 357 ; its dimethyl ester, m.p. 
 104, has been obtained by heating m-iodo-benzoic ester with copper 
 dust (A. 332, 71). 
 
 p 2 -Biphenyl-dicarboxylic acid decomposes at a higher temperature. 
 It is obtained from benzidin and by oxidising p 2 -ditolyl. Its dimethyl 
 ester, m.p. 212, is obtained from p-iodo-benzoic ester and copper 
 (A. 332, 73). 
 
 p 2 -Diamido-biphenyl-m 2 -dicarboxylic acid is obtained from o-nitro- 
 benzoic acid, just as p 2 -diamido-diphenic acid is prepared from m-nitro- 
 benzoic acid (B. 25, 2797 ; 31, 2574). It is converted through its 
 tetrazo-compounds into p 2 -dioxy-biphenyl-m 2 -diearboxylic acid, di- 
 salicylic acid, m.p. 3O2-305. 
 
 m 2 -Dimethyl-biphenyl-p 2 -dicarboxylic acid melts above 300, is 
 formed from o-tolidin, and is oxidised to diphthalic acid, biphenyl-m 2 , 
 p 2 -dicarboxylic acid (CO 2 H) 2 [3, 4]C 6 H 3 .C 6 H 3 [3, 4](CO 2 H) 2 (B. 26, 2486). 
 
 VOL. II. 2O 
 
562 ORGANIC CHEMISTRY 
 
 1. B. Diphenyl-benzols, diphenyl-phenylenes C 6 H 4 (C 6 H 5 ) 2 . Two such 
 bodies are known : m-diphenyl-benzol, iso-diphenyl-benzol, melting at 
 85 and boiling at 369, and p-diphenyl-benzol, melting at 205 and 
 boiling at 383. They are formed simultaneously on conducting 
 benzene through a tube heated to redness, and by the action of diazo- 
 benzol chloride upon diphenyl and A1 2 C1 6 (B. 26, 1998). The p-body 
 is also produced in the action of sodium upon a mixture of p-dibromo- 
 benzol and bromo-benzol (A. 164, 168). Iso-diphenyl-benzol is also 
 prepared from m-dichloro-benzol and chloro-benzol by the action of 
 sodium in xylol (B. 29, R. 773). 
 
 p-Diphenyl-phenol C 6 H 3 (OH)[2, 4](C 6 H 5 ) 2 , formed by the condensa- 
 tion of cinnamic aldehyde and sodium phenyl-succinate, by means of 
 acetic anhydride, the intermediately formed diphenyl-butadiene-acetic 
 acid C 6 H 5 CH : CH.CH : C(C 6 H 5 )CH 2 COOH undergoing benzene ring 
 condensation ; the phenol, on distillation with zinc dust, gives p- 
 diphenyl-benzol (B. 36, 1407). 
 
 2, 6-Diphenyl-l, 4-nitro-phenol (C 6 H 5 ) 2 [2, 6]C 6 H 2 [4]NO 2 [i]OH, m.p. 
 136, is obtained synthetically from dibenzyl-ketone and nitro-malonic 
 aldehyde. It has been converted into the corresponding amido-phenol, 
 quinone, and hydroquinone (C. 1900, II. 560). The latter substance 
 has also been obtained by way of diphenyl-nitroso-phenol, formed, 
 besides phenyl-nitroso-phenol, from nitroso-phenol and two molecules 
 diazo-benzol chloride (A. 312, 227). 
 
 Di-biphenyl C 6 H 5 .C 6 H. 4 C 6 H 4 .C 6 H 5 , m.p. 320, from p-iodo-biphenyl 
 and copper (A. 332, 52). 
 
 I. C. Triphenyl-benzols C 6 H 3 (C 6 H 5 ) 3 . The symmetrical or [i, 3, 5] 
 modification is formed from aceto-phenone when heated with P 2 O 6 , 
 or by conducting hydrochloric acid gas into it, just as mesitylene is 
 obtained from acetone. It melts at 169 (B. 23, 2533). [i, 2, 3] (?)- 
 Triphenyl-benzol melts at 157 (B. 26, 69). Synthetically, several 
 hydrated derivatives of [i, 2, 3]-triphenyl-benzol (cp. C. 1898, II. 
 979 ; 1904, I. 806 ; B. 32, 2009). 
 
 I. D. 1, 2, 4, 5-Tetraphenyl-benzol C 6 H 2 (C ? H 5 ) 4 , m.p. 278, from the 
 cyclic pinacone obtained from diphenyl-dibenzoyl-butadiene (q.v.) 
 (A. 302, 210). 
 
 II. BENZYL-BENZOL GROUP. 
 
 Benzyl-benzol or diphenyl-methane is the simplest hydrocarbon 
 of this group. The alkyl diphenyl-methanes and the compounds 
 substituted in the benzene residues by the NO 2 , NH 2 , or OH groups 
 are derived from it. If we suppose a hydrogen atom of the CH 2 group 
 to be replaced by OH, we obtain the formula of benzo-hydrol or 
 diphenyl-carbinol, which changes by oxidation to benzo-phenone 
 or diphenyl - ketone. Diphenyl-methane CH 2 (C 6 H 5 ) 2 , benzo-hydrol 
 HOCH(C 6 H 5 ) 2 , and benzo-phenone CO(C 6 H 5 ) 2 are the simplest repre- 
 sentatives of the hydrocarbons, the secondary alcohols and the ketones 
 of this group. Attached to them are the corresponding carboxylic 
 acids e.g. : 
 
 H < CO > H CH(OH)/ C H * CO * H CO /C 6 H 4 C0 2 H 
 
 C 6 H 5 \C 6 H 5 \C 6 H 6 
 
 Benzo-benzoic acid Benzo-hydrol-benzoic acid Benzoyl-benzoic acid. 
 
BENZYL-BENZOL GROUP 563 
 
 i. HYDROCARBONS (DIPHENYL-METHANES). 
 
 Formation. (i) From benzyl chloride, benzene and zinc dust 
 (Zincke, A. 159, 374), or aluminium chloride (Friedel and Crafts). (2) 
 From formaldehyde, methylal, or methylene diacetate with benzene 
 and sulphuric acid (Baeyer, B. 6, 963). Both reactions are capable of 
 wide generalisation. Thus, by use of the second reaction, substituting 
 other aldehydes for formaldehyde, numerous hydrocarbons have been 
 obtained in which two benzene residues are attached to the same 
 carbon atom (see unsym. diphenyl-methane, below). (20) Benzyl 
 alcohol and benzene, by treatment with concentrated sulphuric acid, 
 yield diphenyl-methane (B. 6, 963). (3) By the reduction of ketones, 
 into which the benzyl - benzols are oxidised. Diphenyl-methane 
 derivatives are formed as by-products. (4) By the action of sodium 
 upon mixtures of bromo-benzols and alkyl-benzols (B. 33, 334). 
 (5) By the oxidation of alkyl-benzols with manganese dioxide 
 and sulphuric acid, from which we obtain tolyl-phenyl-methane 
 (B. 33, 464). 
 
 Diphenyl-methane C 6 H 5 .CH 2 .C 6 H 5 , benzyl-benzol, is obtained (i) 
 from benzyl chloride and benzene with zinc dust or A1C1 3 . (2) From 
 CH 2 C1 2 with benzene and A1C1 3 . (3) From methylal, or (4) from benzyl 
 alcohol, benzene, and sulphuric acid. (5) By the reduction of benzo- 
 phenone with zinc dust or zinc and sulphuric acid, or hydriodic acid 
 and phosphorus ; and (6) upon distilling diphenyl-acetic acid with soda- 
 lime (A. 155, 86). 
 
 Diphenyl-methane possesses the odour of oranges. It melts at 
 26-5 and boils at 261. When conducted through ignited tubes it 
 yields diphenylene-methane or fluorene ; a chromic acid mixture 
 oxidises it to benzo - phenone, whereas concentrated nitric acid 
 changes it to p 2 -, o, p-dinitro-, and tetra-nitro-diphenyl-methane 
 (A. 283, 154)- 
 
 Benzyl -toluenes, phenyl - tolyl - methanes C 6 H 5 .CH 2 .C 6 H 4 .CH 3 . A 
 liquid mixture of o- and p-benzyl-toluol, which cannot be separated, 
 is obtained by the action of zinc dust on a mixture of benzyl chloride 
 and toluol. Anthracene is formed at the same time. The pure para- 
 body has been formed by heating para-phenyl-tolyl-ketone with zinc 
 dust, and is a liquid, boiling at 285. It appears also to be produced 
 in the action of sodium upon p-bromo-toluol along with p-ditolyl. 
 Bromo - mesitylene and sodium yield, together with dimesityl, a 
 pentamethyl-diphenyl-methane (B. 29, in). 
 
 Benzyl-p-xylene boils at 294. Benzyl-mesitylene melts at 36 and 
 boils at 301. The benzyl-durols melt at 60 and boil at 310 ; and at 
 145 and 326. Benzyl-penta-ethyl-benzol melts at 88 (B. 26, R. 58). 
 p 2 -Ditolyl-methane melts at 22 and boils at 286. Dimesityl-methane 
 melts at 139. The unsym. hydrocarbons were obtained according to 
 methods i and 4, and the sym. according to method i. 
 
 Nitro-diphenyl-methanes C 6 H 3 .CH 2 .C 6 H 4 .NO 2 (A. 283, 157). The 
 o^Ao-compound, prepared from o-nitro-benzyl chloride and benzene 
 with A1C1 3 , is liquid (B. 18, 2402 ; 29, 1303). The meta- and para- 
 bodies are derived from meta- and para-nitro-benzyl alcohol by means 
 of benzene and sulphuric acid. The first is an oil ; the second melts 
 at 31 (B. 16, 2716). 
 
564 ORGANIC CHEMISTRY 
 
 o 2 -Dinitro-diphenyl-methane,m.p. 159, from p 2 -diamido-o 2 -dinitro- 
 diphenyl-methane by de-amidation (/. pr. Ch. 2, 65, 327). 
 
 m 2 -Dinitro-diphenyl-methane, melting at 174, is formed from 
 m-nitro-benzyl alcohol with nitro-benzol, or from formaldehyde, nitro- 
 benzol, and concentrated sulphuric acid (B. 27, 2293, 2321). m, p-Di- 
 nitro-diphenyl-methane, p-nitro-benzyl-m-nitro-benzol melts at 103. 
 p 2 -Dinitro-diphenyl - methane melts at 183. It is obtained from 
 diphenyl-methane along with o, p-dinitro-diphenyl-methane, melting 
 at 118 (B. 27, 2110 ; A. 194, 363). 
 
 Tetranitro - diphenyl - methane, melting at 172, forms dark-blue 
 coloured salts with alcoholic potash (B. 21, 2475). 
 
 Amido-diphenyl-methanes. o-Amido-diphenyl-methane is a liquid. 
 When its vapours are conducted over ignited lead oxide, acridin (q.v.) 
 results. Nitrous acid converts it into fluorene (B. 27, 2786). m- and 
 p-Amido-diphenyl-methane melt at 46 and 34 respectively (B. 16, 2718). 
 
 o 2 -Diamido-diphenyl-methane, m.p. 160 (see /. pr. Ch. 2, 65, 331). 
 
 p 2 -Diamido-diphenyl-methanes are formed (i) from methylene 
 dianilines on heating with aniline chlorohydrates ; in this reaction 
 amido-benzyl anilines may be formed as intermediate products, which 
 are further transposed into diamido-diphenyl-methanes : 
 
 C 6 H 5 NH.CH 2 .NHC 6 H 5 > C 6 H 5 NH.CH 2 C 6 H 4 NH 2 > NH 2 C 6 H 4 CH 2 C 6 H 4 NH 2 
 
 This reaction is confirmed (2) by the easy formation of diamido-diphenyl- 
 methanes from amido-benzyl-anilines by heating with aniline chloro- 
 hydrates (C. 1900, I. mo ; cp. B. 33, 250). 
 
 p 2 -Diamido-diphenyl-methane, melting at 85, changes completely 
 to para-rosanilin or rosanilin when heated with aniline or o-toluidin 
 in the presence of an oxidising agent (B. 25, 303). 
 
 Its tetmmethyl derivative results from dimethyl-aniline by means of 
 C 2 H 2 I 2 , CClgH (or CC1 4 ), or with methylal, or by the action of CS 2 and 
 zinc upon dimethyl-aniline. It melts at 90. 
 
 The hydrogen of the group CH 2 attached to basic radicles is very 
 readily replaced by sulphur ; see p 2 -tetramethyl-diamido-thio-benzo- 
 phenone. See A. 283, 149, for isomeric diamido-diphenyl-methanes. 
 
 p 2 -Diamido-o 2 -dinitro-diphenyl-methane and its reduction products, 
 see C. 1910, II. 569. p 2 -Dihydrazino-diphenyl-methane CH 2 (C 6 H 4 . 
 NHNH 2 ) 2 , m.p. 140 (/. pr. Ch. 2, 74, 155). 
 
 Oxy-benzyl-benzols. p-Benzyl-phenol, melting at 84 and boiling 
 at 325 (in CO 2 ), is produced (i) from benzyl chloride, phenol, and zinc ; 
 (2) from benzyl alcohol, phenol with concentrated sulphuric acid, or 
 zinc chloride ; (3) from p-amido-diphenyl-methane. 
 
 The bromination products of this phenol, like the brominated 
 phenol-alcohol bromides, can easily be converted into methylene- 
 quinones, e.g. C 6 H 5 CH : C 6 H 2 Br 2 : O+H 2 O, a yellow precipitate, easily 
 passing into dibromo-oxy-benzo-hydrol (A. 334, 367) : 
 
 Amido-benzyl-phenols are easily obtained by the condensation of 
 amido-benzyl alcohols with phenols (C. 1903, I. 288). 
 
 p-Dialkyl- amido-benzyl -phenols, e.g. C 6 H 2 OHBr 2 .CH 2 .C 6 H 4 [4]N 
 (CH 3 ) 2 , are formed by the action of o- and p-pseudo-phenol bromides 
 upon tertiary anilines (A. 334, 264). 
 
 o 2 -Dioxy-diphenyl-methane is only known in the form of its an- 
 hydride, xanthene (q.v.). 
 
BENZYL-BENZOL GROUP 565 
 
 p 2 -Dioxy-diphenyl-me thane is produced on fusing diphenyl-methane- 
 disulphonic acid with KOH (A. 194, 318). It melts at 158. Its 
 dimethyl ether is formed from anisol and methylal by the action of 
 concentrated sulphuric acid (B. 7, 1200), and melts at 52 (B. 7, 1200). 
 By exhaustive bromination it is converted into a hepta-bromide, which 
 easily splits off HBr and turns into a methylene-quinone O : C 6 Br 3 H : 
 CHC 6 BrH 3 (OH), red needles, m.p. 245 (/. pr Ch. 2, 58, 441 ; A. 330, 
 61). Substituted p 2 -dioxy-diphenyl-methanes have been obtained, in 
 various ways, from p-oxy-benzyl alcohols, and the derived pseudo- 
 phenol haloids (A. 356, 124). 
 
 Multivalent phenols are easily concentrated by formaldehyde into 
 polyoxy-diphenyl-methanes : methylene-dipyro-eateehin, m.p. 220 with 
 decomposition (B. 26, 254). Methylene-diresorcin, methylene-diorein, 
 methylene-diphloro-gluein (A. 329, 269 ; C. 1907, I. 547). 
 
 Methylene-bis-hydro-resorcinCH 2 (C 6 H 7 O 2 ) 2 , m.p. 132, from hydro- 
 resorcin and formaldehyde, on boiling with acetic anhydride, yields 
 octohydro-xanthene-dione CH 2 (C 6 H 6 O) 2 O, and with ammonia deka- 
 hydro-acridin-dione CH 2 (C 6 H 6 O) 2 NH (A. 309, 356). 
 
 2. ALCOHOLS (BENZO-HYDROLS). 
 
 Diphenyl-carbinol, benzo-hydrol (CgH^CH.OH melts at 68 and 
 boils at 298 with partial decomposition into water and benzo-hydrol 
 ether [(C 6 H5) 2 .CH] 2 O, melting at 109 (B. 34, 1965). It is produced 
 on heating diphenyl-bromo-methane with water to 150, or, more readily, 
 from benzo-phenone with sodium amalgam, or by heating with alcoholic 
 potassium hydroxide and zinc dust (together with benzo-pinacone) 
 (A. 184, 174). Synthetically, it is prepared from formic ester with 
 phenyl-magnesium bromide (C. 1902, II. 1209). By oxidation it 
 passes into benzo-phenone, also by heating in the presence of palladium 
 black (R. 36, 2816). With quinones and quinoid substances benzo- 
 hydrol condenses with entrance of one or two CH(C 6 H 5 ) 2 groups into 
 the quinoid nucleus (B. 32, 2146 ; 33, 799). 
 
 Phenyl-p-tolyl-carbinol melts at 52 (A. 194, 265). 
 
 Diphenyl-carbinol chloride, diphenyl - chloro - methane, melting at 
 14, is obtained from benzo-hydrol and HC1. When heated it breaks 
 down into HC1 and tetraphenyl-ethylene (B. 7, 1128). Diphenyl- 
 bromo-methane, from diphenyl -methane and bromine, melts at 
 
 45- 
 
 Benzo-hydrylamine NH 2 .CH(C 6 H 5 ) 2 , b.p. 288, is obtained from 
 diphenyl-bromo-methane and from benzo-phenon-oxime (B. 19, 3233). 
 The latter method has afforded the homologous alkyl-benzo-hydroxyl- 
 amines (B. 24, 2797). The formyl derivative, from benzo-phenone 
 and ammonium formate at 200-25o (B. 19, 2129), melts at 132. 
 Formamidine-benzo-hydryl CH(NH)NHCH(C 6 H 5 ) 2 is formed from 
 prussic sesqui-chlorohydrate 2CNH.3HC1, benzene, and A1C1 3 (B. 
 31, 1771). 
 
 Dibenzo-hydrylamine melts at 136. 
 
 Phenyl-benzo-hydrylamine C 6 H 5 NH.CH(C 6 H 5 ) 2 , b.p. 20 233, is 
 formed when C 6 H 5 MgBr is attached to benzyliden e-aniline and the 
 product is decomposed with acids (B. 38, 1767). 
 
 /3-Benzo-hydryl-hydroxylamine [diphenyl-aminol -methane} HO.NH 
 
566 ORGANIC CHEMISTRY 
 
 CH(C 6 H 5 ) 2 , m.p. 78, is formed on boiling a solution of diphenyl- 
 bromo-methane and acetoxime with glacial acetic acid and water 
 (A. 278, 364)- 
 
 Benzo-hydryl-hydrazin (C 6 H 5 ) 2 CH.NHNH 2 , m.p. 59, b.p. 12 188, 
 and bis-benzo-hydryl-hydrazin (C 6 H 5 ) 2 CH.NHNH.CH(C 6 H 5 ) 2 m.p. 
 133, from benzo-phenone-hydrazone and bis-benzo-phenone-hydrazone 
 by reduction with sodium amalgam and alcohol. Benzo-hydryl- 
 hydrazin, on boiling with HC1, splits into diphenyl-chloro-methane and 
 hydrazin (/. pr. Ch. 2, 67, 112). 
 
 o-Amido-benzo-hydrol C 6 H 4 / (OH)C6H5 , m.p. 120, is formed 
 
 \rsrl 2 
 
 in the reduction of o-amido-benzo-phenone. It is capable, like 
 o-amido-benzyl alcohol, of producing heterocyclic compounds (B. 29, 
 1034). The isomeric o-oxy-benzo-hydrylamine c 6 H 4 /(NH 2 )C 6 H 5 , 
 
 m.p. 103, is obtained by reduction of phenyl-indoxazene (C. 1898, 
 II. 284). 
 
 p-Oxy-benzo-hydrol HO[4]C 6 H 4 CH(OH)C 6 H 5 , m.p. 161, from 
 benzoyl-phenol by reduction (A. 210, 253). op-Dioxy-benzo-hydrol is 
 formed by condensation of benzaldehyde and resorcin by means of 
 alkali (C. 1910, I. 920). o 2 p 2 -Tetramethoxy-l3enzo-hydrol, m.p. 179, 
 from vic-iodo-resorcino-dimethyl ether, Mg, and formic ester (A. 
 372, 128). 
 
 In the aldol condensation of benzaldehyde, or p-nitro-benzaldehyde 
 and dimethyl-aniline, with hydrochloric acid (by ZnCl 2 or oxalic acid 
 the products are triphenyl-methane derivatives) there arise : p-nitro- 
 p-amido-benzo-hydrol NO 2 C 6 H 4 CH(OH)C 6 H 4 NH 2 (C. 1901, I. 866), 
 p-dimethyl-amido-benzo-hydrol C 6 H 5 CH(OH).C 6 H 4 N(CH 3 ) 2 , m.p. 69, 
 and p-dimethyl-amido-p-nitro-benzo-hydrol, m.p. 96 (B. 21, 3292). 
 By reduction the latter compound yields p-dimethyl-amido-p-amido- 
 diphenyl-methane, m.p. 165. p 2 -Tetramethyl-diamido-benzo-hydrol, 
 m.p. 96, has been obtained by the reduction of p 2 -tetramethyl-diamido- 
 benzo-phenone (B. 22, 1879). On boiling the former with dilute 
 mineral acids until the blue colour has disappeared, it breaks down into 
 dimethyl-aniline and dimethyl-amido-benzaldehyde (B. 27, 3316). In 
 the solid condition p 2 -tetramethyl-diamido-benzo-hydrol is white, 
 while its solution is blue in colour (B. 20, 1733, footnote). In acid 
 solution the tetramethyl-diamido-benzo-thio-hydrol has, like auramin, 
 perhaps a quinoid structure (B. 30, 2803 ; 33, 283). It is a very 
 reactive body. On standing, or on boiling with alcohols, ethers are 
 generated. Methyl ether CH 3 OCH[C 6 H 4 N(CH 3 ) 2 ] 2 , m.p. 72 (C. 1902, 
 I. 471) ; with SH 2 it yields in alcoholic solution tetramethyl-diamido- 
 benzo-thio-hydrol HS.CH[C 6 H 4 N(CH 3 ) 2 ] 2 , m.p. 82. With aromatic 
 amine it spontaneously transposes into tetramethyl-diamido-benzo- 
 hydryl-aryl-amines ArNHCH[C 6 H 4 N(CH 3 ) 2 ] 2 , the so-called aryl-leuc- 
 auramines. The simplest leucauramine NH 2 CH[C 6 H 4 N(CH 3 ) 2 ] 2 , m.p. 
 135, is formed from auramine by reduction with sodium amalgam in 
 alcohol ; oxidation regenerates auramine. With Am sulphide the 
 leucauramines yield tetramethyl - diamido - benzo - hydryl sulphide 
 S[CH[C 6 H 4 N(CH 3 ) 2 ] 2 ] 2 , m.p. 172 (B. 35, 375, 913). With compounds 
 having a reactive CH 2 group, like malonic ester, aceto-acetic ester, etc., 
 the hydrol easily unites with expulsion of water (C. 1910, 1. 181). With 
 
BENZYL-BENZOL GROUP 567 
 
 quinones and quinoid substances it condenses like benzo-hydrol itself 
 (B. 34, 881, etc.). 
 
 3. KETONES (BENZO-PHENONES). 
 
 The ketones of the benzyl-benzol group bear the same relation to 
 the benzoic acids that the acetones bear to the fatty acids : 
 
 CH,CO S H CO3 C 6 H 5 .C0 2 H CO 
 
 ,H 3 X ^ il 5 
 
 Acetic acid Acetone Benzoic acid Benzo-phenone. 
 
 This analogy is shown in the various methods of formation. 
 Methods of Formation. (i) By oxidising (a) the benzyl-benzols 
 and (b) the benzo-hydrols with chromic acid : 
 
 CH / C H5 2 -> co/ c ' H5 
 
 ' Ha \C 6 H 5 ~ \C 8 H 5 
 
 If the CH 2 group contains alkyls or carboxyl these groups will be 
 split off by the oxidation, with the production of ketones. If the 
 benzene residues contain alkyl groups these are converted into carboxyl 
 groups. 
 
 (2) By the action of hot water upon the ketone chlorides (see 
 Benzo-phenone chloride, below). 
 
 Nuclear Syntheses. (3) By the distillation of the calcium salts of 
 mononucleus, aromatic monocarboxylic acids, the CO 2 H groups of 
 which are in direct union with the benzene residue : 
 
 (C 6 H 5 .C0 2 ) 2 Ca -- * (C 6 H 5 ) 2 CO+C0 3 Ca. 
 
 (4) By the condensation of benzoic acid or its anhydride on heating 
 with benzene and P 2 5 . 
 
 (5) By the action of benzoyl chloride on benzene, in the presence 
 of aluminium chloride. 
 
 Phosgene reacts in the same manner, and acid chlorides are the 
 first products. These then change into ketones (B. 10, 1854) : 
 
 C 6 H 6 +COC1 2 L> C 6 H 5 .COC1+C 6 H 6 -U C 6 H 5 COC 6 H 5 . 
 
 (6) By the action of carbon tetrachloride upon aromatic hydro- 
 carbons and their halogen substitution products, in the presence of 
 A1C1 3 , benzo-phenone chlorides are obtained, which, on heating with 
 water, turn into ketones (C. 1904, I. 283 ; 1905, I. 1248). 
 
 (7) By the action of mercury diphenyl upon the acid chlorides 
 e.g. benzoyl chloride. 
 
 Behaviour. (i) On heating with zinc dust or hydriodic acid and 
 amorphous phosphorus, the ketones sustain a reduction of the CO 
 group and revert to the hydrocarbons ; for example, benzo-phenone 
 yields diphenyl - methane. (2) Sodium amalgam changes them to 
 secondary alcohols (benzo-hydrols) and pinacones. (3) Splitting up of 
 alkylated benzo-phenones by heating with phosphoric acid, HI or 
 HC1, into hydrocarbons and carboxylic acids (see B. 32, 1565; 1908). 
 
 Benzo-phenone, diphenyl-ketone CO(C 6 H 5 ) 2 , is known in two modifi- 
 cations, the unstable (labile), melting at 26, and produced on boiling 
 the stable form, melting at 46. The unstable modification slowly 
 reverts to the more stable variety. This takes place rapidly, and with 
 
568 ORGANIC CHEMISTRY 
 
 a very perceptible evolution of heat, upon touching it, with a trace of 
 the stable variety (B. 26, R. 380 ; C. 1898, I. 1177 ; 1900, I. 340). It 
 boils at 307 (760 mm.) and at 162 (12 mm.). It is produced according 
 to the general methods : (i) by oxidising diphenyl-methane, unsym- 
 metrical diphenyl-ethane, benzo-hydrol, diphenyl-acetic acid, etc. ; 
 (2) from benzo-phenone chloride ; (3) by the distillation of calcium 
 benzoate (Peligot, A. 12, 41) ; (4) by the action of P 2 O 5 upon benzoic 
 acid and benzene ; (5) from phosgene or benzoyl chloride, benzene 
 and aluminium chloride ; and (6) from benzoyl chloride and mercury 
 diphenyl. It is also found with benzoic acid and triphenyl-carbinol 
 (7) among the products of the action of C0 2 upon C 6 H 5 MgBr (B. 36, 
 3005). On fusing with potassium hydrate it dissolves into benzoic 
 acid and benzene, and on heating with sodium amide, in benzene 
 solution, into benzamide and benzene (C. 1909, II. 22). It is converted 
 into diphenyl-methane, benzol-hydrol, and benzo-pinacone by reduc- 
 tion. Hexahydro-benzo-phenone, m.p. 54, from hexahydro-benzoyl 
 chloride, benzene, and A1C1 3 (B. 30, 1940). 
 
 Benzo-phenone Homologues. o-Phenyl-tplyl-ketone, b.p. 315, when 
 conducted over heated lead oxide, passes into anthra-quinone (q.v.), 
 while it yields anthracene when heated with zinc dust (B. 6, 754). 
 m-Phenyl-tolyl ketone boils at 314. 
 
 p-Tolyl-phenyl ketone is known in two modifications : the unstable 
 (labile) form melts at 55 ; it is hexagonal. The stable form, m.p. 
 59, is monoclinic (A. 189, 84 ; B. 12, 2299). 
 
 p-Ditolyl ketone melts at 92 and boils at 333. Benzoyl-xylol melts 
 at 36 and boils at 317 (B. 17, 2847). Benzoyl-mesitylene melts at 
 36 and boils at 317. Mesitoyl-mesitylene, m.p. 85 (/. pr. Ch. 2, 
 35, 486), etc. All these are most conveniently prepared by method 5. 
 
 Derivatives of Benzo-phenone obtained by the Replacement of Oxygen. 
 Benzo-phenone chloride, diphenyl-dichloro-methane CC1 2 (C 6 H 5 ) 2 , boiling 
 at 193 (30 mm.), is produced when PC1 5 acts upon benzo-phenone. 
 Also by the action of benzene upon carbon tetrachloride in the presence 
 of A1C1 3 (C. 1905, I. 1248). 
 
 When heated with water it reverts to benzo-phenone, while with 
 silver it yields tetraphenyl-ethylene, and with zinc dust tetraphenyl- 
 ethylene, a- and j8-benzo-pinacolin (B. 29, 1790). By transposition 
 with two molecules sodium azide, nitrogen is split off, and N, a-diphenyl- 
 
 tetrazol C 6 H 6 c/ ' 5 ' \\ is formed (B. 42, 3359). 
 
 ^N N 
 
 Benzo-phenone bromide CBr 2 (C 6 H 5 ) 2 is produced on dropping 
 bromine into diphenyl-methane heated to 150. 
 
 Acetals of benzo-phenone are obtained from benzo-phenone chloride 
 with sodium alcoholates, as well as from benzo-phenone and ortho- 
 formic ethers. Benzo-phenone dimethyl and diethyl acetals melt at 
 107 and 52, and boil at 289 and 295 respectively (B. 29, 2932 ; 
 R- 774> 
 
 Thio-benzo-phenone CS(C 6 H 5 ) 2 is derived from benzene by means of 
 thio-phosgene, CS 2 C1 2 , and aluminium chloride. In this reaction the 
 phenol ethers react more readily than the hydrocarbons (B. 28, 2869). 
 Thio-benzo-phenone is further produced by the action of phosphorus 
 sulphide upon benzo-phenone, but best of all when an alcoholic solution 
 
BENZYL-BENZOL GROUP 569 
 
 of potassium sulphide reacts with benzo-phenone chloride. It is an 
 intensely blue-coloured oil, which congeals at lower temperatures to 
 blue needles, and under a pressure of 14 mm. distils at 174. The 
 thio-benzo-phenones, when acted upon with metallic copper, yield 
 tetraphenyl-ethylene (B. 29, 2944). 
 
 Benzo-phenone-diethyl-anddibenzyl-mereaptol (C 6 H 5 ) 2 C(SCH 2 C 6 H 5 ) 2 
 m.p. 144, on careful oxidation, yield the corresponding sulphonals, 
 m.p. 137 and 208 (B. 35, 2343). 
 
 Diphenyl-dinitro-methane (C 6 H 5 ) 2 C(N 2 O 4 ), melting at 78, results 
 upon saturating a solution of benzo-phenone-oxime in ether with nitro- 
 gen tetroxide. It is changed back to benzo-phenone-oxime with zinc 
 dust and glacial acetic acid. Benzo-hydrylamine is also formed (B. 23, 
 3490). 
 
 Imino-benzo-phenone (C 6 H 5 ) 2 C=NH is a colourless oil, obtained 
 in the action of dry ammonia upon a chloroform solution of amido- 
 benzo-phenone chlorohydrate. The chlorohydrate results when benzo- 
 phenone chloride is heated with ure thane to 130. Phenyl-benzal- 
 sultime C 6 H 4 <^^ CeH6 ^N, melting at 164, should be viewed as a deriva- 
 
 XSOg ' 
 
 tive of imino-benzo-phenone, produced in the condensation of pseudo- 
 saccharin chloride with benzene and aluminium chloride (B. 29, 2296). 
 
 Phenyl-imino-benzo-phenone, benzo - phenone - anile (C 6 H 5 ) 2 C = N . 
 C 6 H 5 , melting at 116, is formed from benzo-phenone chloride and ani- 
 line (A. 187, 199), or benzo-phenone and aniline at 240-25O, as well 
 as by the action of C 6 H 5 MgBr upon phenyl-imino-benzoic ester C 6 H 5 C 
 (OCH 3 ) : NC 6 H 5 (C. 1906, 1. 1431). It forms unstable salts with acids, 
 and with methyl iodide an addition product, m.p. 202 (B. 35, 2615). 
 A series of o-substituted benzo-phenone-aniles, all coloured more or less 
 strongly yellow (cp. auramin) have been obtained from the corre- 
 sponding ketones by heating with aniline in the presence of sulphuric 
 acid (B. 32, 1683). 
 
 Benzo-phenonoxime (C 6 H 5 ) 2 C : N.OH, melting at 140, is known in 
 only one modification (for the possible existence of an unstable form, 
 consult B. 28, R. 1008), while unsymmetrical benzo-phenones e.g. 
 bromo-benzo-phenone and phenyl-tolyl-ketone each form two oximes 
 (B. 23,2776). 
 
 Hexahydro-benzo-phenone also forms two oximes a-, m.p. 158 ; 
 j3-, m.p. in the first of which, on transformation, yields benzoyl- 
 amido-hexamethylene, while the second yields hexahydro-benzanilide 
 (B. 30,2862). 
 
 Benzo-phenone-hydrazone (C 6 H 5 ) 2 C : NNH 2 , m.p. 98, and bis- 
 benzo-phenone-hydrazone, diphenyl-ketazin (C 6 H 5 ) 2 C : N.N : C(C 6 H 5 ) 2 , 
 m.p. 162 (/. pr. Ch. 2, 44, 194). Benzo-phenone-semi-earbazone, 
 m.p. 165. The phenyl-hydrazone (C 6 H 5 ) 2 C : N 2 H.C 6 H 5 melts at 137 
 (B. 19, R. 302). 
 
 Benzo-phenone Halogen Derivatives are mostly produced by method 
 5 (p- 5^7)- o-Bromo-benzo-phenone, melting at 42, is noteworthy 
 because of the mobility of its bromine atom. If o-bromo-benzo- 
 phenone-oxime, melting at 132, be acted upon with caustic alkali it 
 
 splits off hydrogen bromide and becomes phenyl-indoxazene C 6 H 4 < 
 
570 ORGANIC CHEMISTRY 
 
 (B. 27, 1452), while m- and p-bromo-benzo-phenone, on the other hand, 
 yield with o-bromo-benzo-phenone two isomeric oximes (B. 25, 3292 ; 
 A. 264, 152, 171). 
 
 The sym. m-, p-dibromo-benzo-phenones (BrC 6 H 4 ) 2 CO, melting at 
 142 and 171, yield but one oxime (A. 264, 160). o-, p-Dibromo-benzo- 
 phenone, melting at 52, yields one oxime, melting at 141 ; this can be 
 readily rearranged to p-bromo-phenyl-indoxazene (B. 27, 1453). 
 
 o-Chloro-benzo-phenone-oxime shows less readily, and o-iodo-benzo- 
 phenone-oxime more readily, than o-bromo-benzo-phenone-oxime the 
 formation of phenyl-indoxazene (B. 26, 1250). 
 
 Benzo-phenone hexachloride C 6 H 5 COC 6 H 5 C1 6 , m.p. 215, from benzo- 
 phenone and chlorine in chloroform, on heating gives triehloro-benzo- 
 phenone C 6 H 5 COC 6 H 2 C1 3 , m.p. 131 (C. 1898, I. 1178). 
 
 Nitro-benzo-phenones. o-, m-, and p-Nitro-benzo-phenone melt at 
 195, 94, and 138 (B. 16, 2717 ; 18, 2401 ; /. pr. Ch. 2, 65, 308). 
 Phenyl-indoxazene is produced when the oxime of the o-body is boiled 
 with caustic soda (B. 26, 1250). On heating at ordinary pressures it 
 forms acridone, probably by way of phenyl-anthranile (B. 42, 591). 
 
 2 -, m 2 -, p 2 -Dinitro-benzo-phenone melt at 188, 148, and 189. 
 o, n-, o, p-, and m, p-Dinitro-benzo-phenone (NO 2 C 6 H 4 ) 2 CO melt at 
 126, 196, and 172. 2 - and o, n-Dinitro-benzo-phenones are formed 
 in the nitration of benzo-phenone (A. 283, 164 ; B. 27, 2111). 2 , p 2 - 
 Tetranitro-benzo-phenone melts at 225 (B. 27, 2318). Other sub- 
 stituted benzo-phenones are described in the A. 286, 306, etc. 
 
 c-Phenyl-anthranile C 6 H 4 {^. (C6H5 ^O, feebly yellow crystals of 
 
 m.p. 53, may be regarded as an inner anhydride of o-hydroxylamino- 
 benzo-phenone. Following anthranile and c-methyl-anthr anile, it 
 is obtained by reduction of o-nitro-aceto-phenone with tin and 
 glacial acetic acid, or by oxidation of o-amido-aceto-phenone with 
 Caro's acid (B. 42, 1723), and, in small quantities, by the condensation 
 of o-nitro-benzaldehyde and benzene, by means of concentrated H 2 SO 4 
 (B. 41, 1845). On heating at ordinary pressure it transposes into the 
 isomeric acridone (B. 42, 592). The same transformation is also 
 produced by the simultaneous action of sulphuric and nitrous acids, 
 probably by way of nitroso-o-hydroxylamino-benzo-phenone (B. 42, 
 1716). Cp. the analogous breaking up of anthranile, and the trans- 
 position of c-methyl-anthranile into indoxyl. Derivatives of phenyl- 
 anthranile are probably represented by a series of compounds obtained 
 by the condensation of o-nitro-benzaldehyde with tertiary anilines and 
 phenols, by means of concentrated HC1 (B. 42, 1714). 
 
 Amido-benzo-phenones are obtained from nitro-benzo-phenones, 
 from benzoic acid, dimethyl-aniline and P 2 O 5 , benzoyl chloride, 
 phthalanile and ZnCl 2 (B. 14, 1838), etc. o-, m-, p-Amido-benzo- 
 phenone melt at 106, 87, and 124. o-Amido-benzo-phenone is made 
 from toluol-sulphon-anthranilic acid chloride, with benzene and A1C1 3 , 
 and saponification of the resulting toluol-sulphon-amido-benzo-phenone 
 (B. 35, 4273 ; 39, 4332). Or from the amide of o-benzoyl-benzoic acid 
 by means of sodium hypo-bromite (B. 27, 3483 ; A. 291, 8). A mixture 
 of o- and p-amino-benzo-phenone in the form of their benzoyl deriva- 
 tives C 6 H 5 CONHC 6 H 4 COC 6 H 5 is obtained by intramolecular atomic 
 migration from the intermediate dibenzoyl-aniline (C 6 H 5 CO) 2 NC 6 H 5 on 
 
BENZYL-BENZOL GROUP 571 
 
 heating aniline with two molecules benzoyl chloride to 220 (C. 1903, 1. 
 924 ; 1904, I. 1404). 
 
 o-Amido-benzo-phenone-oxime, m.p. 156, is rearranged at high 
 temperatures by hydrochloric acid into o-phenylene-benzamidin (B. 24, 
 2385). Acetyl-o-amido-benzo-phenone, m.p. 89. p-Dimethyl-amido- 
 benzo-phenone, p-benzoyl-dimethyl-aniline, m.p. 90, is also formed 
 on heating malachite green with concentrated hydrochloric acid at 180 
 (A. 217, 257 ; B. 21, 3293 ; A. 307, 307), and by heating dimethyl- 
 aniline-phthaloylic' acid. On further derivatives of p-amido-benzo- 
 phenone, see A. 311, 147. 
 
 Ring-formations of o-Amido-benzo-phenone. (i) Acridone is pro- 
 duced when o-amido-benzo-phenone is heated with lead oxide (B. 27, 
 3484). (2) Nitrous acid converts this o-body into fluorenone or 
 diphenylene-ketone (B. 27, 3484). (3) Phenyl-indoxazene is readily 
 obtained from o-amido-benzo-phenone-oxime and nitrous acid (B. 26, 
 1667). (4) When acetyl-o-amido-benzo-phenone is heated with alco- 
 holic ammonia it condenses to a-phenyl-jS-methyl-quinazolin (B. 25, 
 3082). (5) Acetyl-phenyl-isindazol (B. 24, 2383 ; 29, 1255) results 
 when acetyl-o-amido-benzo-phenone-oxime is acted upon by acetic 
 anhydride. (6) o-Amido-benzo-phenone condenses with acetone and 
 sodium hydroxide to a-methyl-y-phenyl-quinolin (B. 18, 2405). 
 (7) When the chlorohydrate of o-amido-benzo-phenone is heated water 
 is eliminated, and there results an anhydro-bis-o-amido-benzo-phenone, 
 which probably contains an " 8-membered " ring (B. 29, 1272) : 
 
 Acridone 
 C a H 4 . 
 
 NH 2 [2]C 6 H 4 \ NO.OH C 6 H 4 \. Fluorenone or di- 
 
 C 6 H 5 / -N,- 2 H^ C.H.A phenylene-ketone 
 
 3. C.H 4 N.OH --> C 6 H 5 N Phenyl-indoxazene 
 
 ' 
 
 X-IJ.A2 
 
 /CO.C 6 H 5 NH 3 /C(C 6 H 5 ) : N a-Phenyl-0-methyl- 
 
 *\NH.CO.CH 3 6 4 \N .CCH 5 quinazolin 
 
 C8H4 C H N CO.CH 3 ' CeH4 <H 3 ) 
 
 r /CO.C 6 H 5 CH.CO.CH. /C(C 6 H 5 ) : CH a-Methyl-y-phenyl- 
 
 4 \NH 2 6 4 \N==C.CH 3 quinolin 
 
 ^ r /COC 6 H 5 -^H t O /C(C 6 H 5 ) : N\_ ' Anhydro-bis-o-amido- 
 
 C(!H4 \.NH 2 C6H4 \N : C(C 6 H 5 ) / C6H4 benzo-phenone. 
 
 Diamido-benzo-phenones. 2 -, m 2 -, p. 2 -Diamido-benzo-phenones 
 melt at 134, 173, and 239 respectively. Nitrous acid converts 
 the o-body into xanthone (q.v.) and o-oxy-fluorenone (B. 28, in). 
 p. 2 -Diamido-benzo-phenone yields substantive cotton dyes (B. 22, 988). 
 
 Tetramethyl-p 2 -diamido-benzo-phenone, Miehler's ketone 
 
 <C TT ^CYPTT ^ 
 r- 6 Tj 4 ^ ^n 3 N results upon heating hexamethvl violet \vith hydro- 
 C 6 H 4 .JN(CH 3 ) 2 
 
 chloric acid (B. 19, 109). It is technically prepared by the action of 
 COC1 2 upon dimethyl-aniline in the presence of A1C1 3 . It melts at 173. 
 Nitrous acid converts it into nitroso-trimethyl-diamido-benzo-phenone 
 
572 ORGANIC CHEMISTRY 
 
 (B. 24, 3198). Dimethyl-aniline and PC1 3 convert it into methyl violet, 
 while it yields Victoria blue with phenyl-naphthylamine. Its oxime 
 melts at 233 (B. 19, 1852). Its hydrazone melts at 174 (B. 35, 366). 
 With two molecules dimethyl sulphate the ketone combines to form a 
 bis-quaternary ammonium salt (/. pr. Ch. 2, 66, 393). 
 
 Tetramethyl - p 2 - diamido-thio-benzo-phenone CS[C 6 H 4 .N (CH 3 ) 2 ] 2 , 
 results from the action of hydrogen sulphide upon an alcoholic auramin 
 solution heated to 60, or it can be prepared from dimethyl-aniline and 
 CSC1 2 . It consists of ruby-red crystalline flakes with a blue lustre or 
 a cantharides-green crystalline powder, melting at 202 (B. 20, 3266, 
 3290 ; C. 1898, 1. 1029) ; on heating with alcoholic NH 3 under pressure 
 it forms auramin base quantitatively. 
 
 Tetramethyl-p 2 -diamido-benzo-phenone imide, auramin base 
 [(CH 3 ) 2 NC 6 H 4 ] 2 C : NH, m.p. 136, combines with dimethy] sulphate 
 to form the methyl sulphate of methyl-auramin (/. pr. Ch. 2, 66, 387). 
 The dyestuff auramin is the chlorohydrate of the auramin base 
 [(CH 3 ) 2 NC 6 H 4 ) 2 C : NH 2 C1, or of a quinoid pseudo-form of it 
 NH^r^CeHj : N(CH 3 ) 2 C1 / oo-i ~ .\ 
 ^\C 6 H 4 N(CH 3 ) 2 (A. 381,234). 
 
 Auramin results when tetramethyl-diamido-benzo-phenone is heated 
 with ammonium chloride and zinc chloride, as well as from p-dimethyl- 
 amido-benzamide by the action of dimethyl-aniline and zinc chloride 
 (B. 28, R. 86). Perfectly analogous dyestuffs are obtained from the 
 primary anilines and diamines (B. 20, 2844 ; 28, R. 65). Auramin, 
 golden-yellow flakes, is important as a cotton dye. Cotton mordanted 
 with tannin is coloured a beautiful yellow by this salt. 
 
 Potassium cyanide changes it to the nitrile of the corresponding 
 tetramethyl-diamido-diphenyl-acetic acid (B. 27, 3294). 
 
 o, m-, o, p-, m, p-Diamido-benzo-phenones melt at 80, 128, and 
 126 respectively (A. 283, 149 ; B. 28, in). 
 
 Benzo-phenone-o-sulphonic acid C 6 H 5 COC 6 H 4 [2]SO 3 H from sulpho- 
 benzoic anhydride with benzene and A1C1 3 (B. 33, 3486). 
 
 Benzo-phenone-3, 3 (P)-disulphonic acid (SO 3 HC 6 H 4 ) 2 CO ; chloride, 
 m.p. 138 (C. 1898, II. 347). 
 
 Oxy-benzo-phenones are formed : (i) From amido-benzo-phenones ; 
 in this change the o-amido-benzo-phenones pass chiefly into fluorenones. 
 (2) By decomposing the xanthones, which may be viewed as cyclic 
 phenyl ethers of o 2 -dioxy-benzo-phenones, with caustic potash. (3) By 
 the condensation of benzoic acids or oxy-benzoic acids and phenols 
 with zinc chloride or phosphorus oxy-chlofide (B. 26, R. 587), sulphuric 
 acid, or tin tetrachloride (B. 23, R. 43, 188 ; 24, 967) . (4) From phenols 
 by means of benzoyl chloride, zinc dust, or zinc chloride, or aluminium 
 chloride (B. 12, 261). (5) By the action of benzo-trichloride and zinc 
 oxide (B. 10, 1969) upon phenols or their benzoyl esters. (6) By the 
 action of alkalies upon benzo-trichloride and phenols (B. 24, 3677). 
 (7) From the phenol-carboxylic chlorides or their methyl-acetyl- or 
 carbo-methoxy derivatives by condensation with benzene and A1C1 3 
 (A. 346, 381 ; B. 42, 1015). 
 
 Oxy-benzo-phenones containing but one Hydroxyl Group in the Benzene 
 Nucleus. o-Oxy-benzo-phenone, o-benzoyl-phenol, melting at 41, is 
 produced, together with the phenyl ester of benzoic acid, by the 6th 
 method of formation ; also from phenyl-indoxazene upon heating it 
 
BENZYL-BENZOL GROUP 573 
 
 with hydriodic acid and phosphorus (B. 29, R. 350). The best method, 
 however, consists in treating methyl-salicylic chloride with benzene 
 and aluminium chloride (B. 35, 2811). o-Methoxy-benzo-phenone, 
 m.p. 39, see B. 41, 332. o-Oxy-benzo-phenone anile, m.p. 138. 
 
 m-Oxy-benzo-phenone, melting at 116, is produced according to 
 methods i, 4, 5, and 7 (B. 25, 3533). m- and p-Methoxy-benzo-phen- 
 one, m.p. 37 and 61 respectively, b.p. 343 and 355, from m- and p- 
 methoxy-benzoyl chloride with benzene and A1C1 3 (B. 35, 2813). 
 
 o 2 -, m 2 -, p 2 -Dioxy-benzo-phenones melt at 173, 162, and 210, and 
 o, m-, o, p-Dioxy-benzo-phenones melt at 126 and 142. They are 
 obtained from the corresponding diamido-benzo-phenones. 
 
 o 2 -Dioxy-benzo-phenone is also made from its anhydride, xanthone 
 or diphenylene ketone oxide, by careful fusion with potassium hydrate 
 (B. 19, 2609). o, p-, and p 2 -Dioxy-benzo-phenones are also produced in 
 the condensation of salicylic acid and phenol with tin tetrachloride (A. 
 354, 177). p 2 -Dioxy-benzo-phenone appears also in the decomposi- 
 tion of aurin, benzaurin, phenol-phthalein, and rosanilin upon heat- 
 ing them with water or caustic potash (B. 16, 1931). m, p-Dioxy- 
 benzo-phenone, m.p. 206, from the diamido-compound. 
 
 Oxy-benzo-phenones containing more than one Hydroxyl attached to 
 the Benzene Nucleus. These are prepared mainly by method 3. Men- 
 tion must be made of the ketones obtained from pyrogallic acid and 
 gallic acid, for they, like alizarine, are dyes. 
 
 The dyestuff prepared from benzoic acid and pyrogallol melts at 
 140. It bears the name alizarin yellow A in trade (A. 269, 295 ; B. 
 32, 1686). Isomeric with the latter is the 3, 4, 5-trioxy-benzo-phenone, 
 m.p. 176, obtained from tricarbo-methoxy-galloyl chloride, benzene, 
 and A1C1 3 (B. 42, 1015). 
 
 2, 5-Dioxy-benzo-pheaone C 6 H 5 COC 6 H 3 [2, 5](OH) 2 , melting at 125, 
 is obtained from benzaldehyde and quinone, exposed to sunlight (B. 
 24, 1340; 41, 143). 
 
 2 p 2 -Tetraoxy-benzo-phenone [(OH) 2 C 6 H 3 ] 2 CO is obtained on melt- 
 ing up fluorescei'n chloride with soda. On heating it passes into dioxy- 
 xanthane (B. 32, 2103). 2, 5, 2', 5'-Tetramethoxy-benzo-phenone, 
 m.p. 109, from iodo-hydroquinone-dimethyl ether, Mg, and CO 2 (B. 
 
 The barks of coto and paracoto, found in Bolivia, and possessing 
 therapeutic value, contain a series of benzo-phenone derivatives. 
 They are : 
 
 Cotoin C 6 H 5 .CO.C 6 H 2 (OH) 2 (OCH 3 ), m.p. 130. 
 
 Hydroeotoin C 6 H 5 .CO.C 6 H 2 (OH)(OCH 3 ) 2 , m.p. 98. 
 
 Methyl-hydrocotoin C 6 H 5 .CO.C 6 H 3 (OCH 3 ) 3 , melting at 113 (B. 25, 
 1119 ; 26, 2340 ; 27, 419), which are methyl ethers of benzoyl phloro- 
 glucin; and protocotoin (CH 3 O) 2 (HO).C 6 H 2 .CO.C 6 H 3 (O 2 CH 2 ), m.p. 
 141, as well as methyl-protocotoin (CH 3 O) 3 .C 6 H 2 .CO.C 6 H 3 (O 2 CH 2 ), m.p. 
 134, derivatives of i, 3, 5-trioxy-benzo-proto-catechone. During the 
 oxidation of protocotoin with permanganate, we obtain aceto-piperone 
 (B. 34, 1468 ; see alsoC. 1907, I. 817). Most closely related with these 
 compounds is, according to recent investigations (B. 39, 4014), the 
 previously mentioned maelurin (OH) 2 [3, 4]C 6 H 3 .CO.C 6 H 2 [2, 4, 6] 
 (OH) 3 , which, on heating with concentrated KOH, decomposes into 
 proto-catechuic acid and phloro-glucin. The pentamethyl ether, 
 
574 ORGANIC CHEMISTRY 
 
 formed by methylation with dimethyl sulphate, and melting at 157, 
 has been obtained synthetically from veratroyl chloride, phloro-glucin- 
 trimethyl ether, and A1C1 3 (B. 39, 4022). 
 
 4. CARBOXYLIC ACIDS OF THE DIPHENYL-METHANE GROUP. 
 
 There are three classes of these acids : A. Diphenyl-methane Car- 
 boxylic Acids ; B. Benzo-hydrol Carboxylic Acids ; C. Benzo-phenone 
 Carboxylic Acids. 
 
 A. Diphenyl-methane Carboxylic Acids. o-, m-, p-Benzyl-benzoie 
 acids CeH 5 .CH 2 .C 6 H 4 .CO 2 H melt at 117, 107, and 154. When the 
 o-acid is digested with sulphuric acid, anthranol (q.v.) is produced (B. 
 25,3022; 27,2789; A. 291, 17; B. 9,633). 
 
 o-Cyano-diphenyl-methane, m.p. 19 and b.p. 313, is obtained from 
 o-cyano-benzyl chloride by means of benzene and aluminium chloride 
 as well as from o-amido-diphenyl-methane. 
 
 Benzyl-iso- and terephthalie acid C 6 H 5 .CH 2 .C 6 H 3 (C0 2 H), see B. 9, 
 
 Diphenyl-methane-o 2 -dicarboxylic acid CH 2 (C 6 H 4 [2]CO 2 H) 2 , m.p. 
 254, results from the reduction of the lactone of benzo-hydrol-o 2 -di- 
 car boxy lie acid, and that of the dilactone of benzo-phenone-o 2 -dicar- 
 boxylic acid. Concentrated sulphuric acid changes it to anthranol- 
 carboxylic acid (A. 242, 253). 
 
 Diphenyl-methane-m 2 -diearboxylie acid melts at 220-225. Di- 
 phenyl-methane-p-dicarboxylic acid melts at 290 (B. 27, 2324). Di- 
 phenyl-methane-o, p-diearboxylie acid, m.p. 220 (A. 309, 115). 
 
 B. Benzo-hydrol-carboxylic Acids. o-Benzo-hydryl-benzoic acid 
 
 , I- -1/-TT _ /-> TT 
 
 lactone, phenyl phthalide c a H 4 j X. 5 , m.p. 115, is formed 
 
 I [21090 
 
 by the reduction of o-benzoyl-benzoic acid, and by the breaking down 
 of benzo-hydrol-o 2 -carboxylic acid on the application of heat. The 
 acid corresponding to the lactone is not capable of existing as such ; 
 its salts, however, are known. PC1 5 converts the lactone into anthra- 
 quinone (B. 21, 2005). 
 
 o-Cyano-benzo-hydrol C 6 H 5 (CHOH)C 6 H 4 [2]CN has been prepared 
 from o-cyano-diphenyl-chloro-methane C 6 H 5 CHC1.C 6 H 4 CN, the reaction 
 product from chlorine and cyano-diphenyl-methane (B. 29, 1315). 
 m- and p-Benzo-hydryl-benzoic acid melt at 121 and at 164 (A. 220, 
 242). p-Tolyl-phthalide melts at 129 ; for its homologues, see A. 234, 
 
 (CH.C 6 H 4 .OH 
 237. Oxy-phenyl-phthalide C 6 H 4 ^ \ , m.p. 180, is obtained 
 
 I COO 
 from phthal-aldehydic acid, phenol, and sulphuric acid (73 per cent.) 
 
 (B. 27,2632 ; 31, 2790). 
 
 ( CH C 6 H 4 C0 2 H 
 
 Benzo-hydrol-o 2 -lactone-carboxylic acid C 6 H 4 { \ , m.p. 
 
 I coo 
 
 202, is produced on heating benzo-hydrol-tricarboxylic acid 
 monolactone (HOOCC 6 H 4 ) 2 C(OH), the reaction product of alkalies 
 upon diphthalic acid (A. 242, 233). 
 
 C. Benzo-phenone-carboxylic acids are formed (i) in the oxidation 
 of the alkyl-diphenyl-methanes, alkyl-benzo-phenones, diphenyl- 
 methane-carboxylic acids, and benzo-hydrol-carboxylic acids ; (2) from 
 
BENZYL-BENZOL GROUP 575 
 
 benzoyl chloride and benzole anhydride with zinc chloride (B. 14, 647) ; 
 (3) from phthalic anhydride and benzene with aluminium chloride. 
 
 o-Benzoyl-benzoie acid C 6 H 5 .CO.C 6 H 4 [2]CO 2 H+H 2 O melts, when 
 anhydrous, at 127. It is produced by oxidising o-tolyl-phenyl-methane, 
 o-methyl-benzo-phenone, o-benzyl- and o-benzo-hydryl-benzoic acid. 
 It can be prepared by method 3. Heated with phosphorus pentoxide, 
 water is eliminated and anthraquinone is produced. Anthracene is 
 produced when it is heated with zinc dust. With benzene and alu- 
 minium chloride ortho-benzoyl-benzoic acid yields phthalo-phenone ; 
 with phenol and stannic chloride, oxy-phthalo-phenone. When di- 
 gested with acetic anhydride (B. 14, 1865) it changes to : 
 
 Aceto-benzoyl-benzoie acid C 6 H 4 {W\^' cacH3 , melting at 117 
 
 (compare aceto-laevulinic acid). The oxime anhydride melts at 162. 
 It is formed when hydroxylamine hydrochloride acts upon benzoyl- 
 benzoic acid. At 130 it yields phthalanil (B. 26, 1262, 1795). Phenyl- 
 
 ( [i]C(C 6 H 5 ) : N 
 lactazame C 6 H 4 ^ , melting at 181 (compare laevulinic 
 
 l[ 2 ]CO - N.C 6 H 5 
 acid) (B. 18, 805). 
 
 Chlorinated benzoyl-benzoic acids have been prepared from chlorin- 
 ated phthalic anhydrides by the action of benzene and aluminium 
 chloride (A. 238, 338), and homologous methyl-benzoyl-benzoic acids 
 from phthalic anhydride and toluol or other methyl benzols (B. 19, 
 R. 686 ; A. 311, 178). Phthalic anhydride and dimethyl-aniHne give 
 dimethyl-aniline-phthaloylic acid C 6 H 4 (COOH)COC 6 H 4 N(CH 3 ) 2 , m.p. 
 205 (A. 307, 305). For transformation and substitution products of 
 this acid, see C. 1901, 1. 631, 944, etc. 
 
 m-Benzoyl-benzoic acid C 6 H 5 .CO.C 6 H 4 [3]CO 2 H, melting at 161, 
 is made from iso-phthalic chloride, benzene, and aluminium chloride 
 (A. 220, 236 ; B. 13, 320). p-Benzoyl-benzoie acid, melting at 194, is 
 prepared according to method I (B. 9, 92). 
 
 Benzo-phenone-o 2 -diearboxylic acid CO(C 6 H 4 [2]CO 2 H) 2 melts ir- 
 regularly at I5o-200 with the elimination of water and a change to 
 the dilactone. It is produced by oxidising benzo-hydrol-o 2 -lactone-car- 
 boxylic acid with potassium permanganate. Benzo-phenone-dicarboxylic 
 COO. ,OCO 
 
 dilactone \ ^ c \ I > melting at 212, is produced on boiling the 
 
 C 6 H 4 s C 6 H 4 
 
 aqueous solution of the acid, as well as by digesting its alcoholic solution 
 with hydrochloric acid (A. 242, 246). 
 
 0, p- and p 2 -Benzo-phenone-diearboxylic acid, m.p. 235 and above 
 360 respectively (A. 309, 98 ; 311, 96). Phthaloyl-salicylic acid 
 COOHC 6 H 4 COC 6 H 3 (OH)COOH, m.p. 244, from salicylic methyl ester, 
 phthalyl chloride, and A1C1 3 (A. 303, 280). 
 
 Benzoyl-phthalic acid C 6 H 5 CO.C 6 H 3 [2, 3](COOH) 2 , from hemi- 
 mellitic anhydride, benzene, and A1 2 C1 6 , melts at 183 with the formation 
 of an anhydride (A. 290, 217). Concentrated sulphuric acid converts 
 it into anthraquinone-carboxylic acid. 
 
 1, 3, 4-Benzoyl-phthalie acid, m.p. 189, is obtained by the oxidation 
 of o-xyloyl-benzoic acid (A. 312, 99). 
 
 Benzyl-diphenyls C 6 H 5 .CH 2 .C 6 H 4 .C 6 H 5 are formed from diphenyl, 
 
576 ORGANIC CHEMISTRY 
 
 benzyl chloride, and zinc dust. p-Benzyl-diphenyl melts at 85 and 
 boils at 285 (100 mm.). Iso-benzyl-diphenyl melts at 54 and boils at 
 283-287 (no mm.) (B. 14, 2242). 
 
 p-Phenyl-benzyl-o-benzoie acid C 6 H 5 [4]C 6 H 4 [i]CH 2 [2]C 6 H 4 [i]CO 2 H 
 melts at 184, and p-phenyl-benzo-hydryl-o-benzoie acid C 6 H 5 [4]C 6 H 4 
 [i]CH(OH).C 6 H 4 [2]CO 2 H melts at 204. Both are produced in the 
 reduction of p-phenyl-benzoyl-o-benzoic acid C 6 H 5 [4]C 6 H 4 [i]CO[2] 
 C 6 H 4 [i]C0 2 H, melting at 225, which results from the action of 
 aluminium chloride upon a ligroi'n solution of diphenyl and phthalic 
 anhydride (A. 257, 96 ; /. pr. Ch. 2, 41, 149). 
 
 Dibenzyl-benzenes. The second benzyl nucleus can be introduced 
 into benzene and its homologues, containing replaceable hydrogen atoms 
 attached to the nucleus, by the same reactions which were employed in 
 introducing the first benzyl nucleus i.e. by the action of zinc dust 
 (B. 9, 31) or aluminium chloride upon a solution of the benzyl chloride 
 in the hydrocarbons, and by the action of sulphuric acid upon benzene 
 and methylal (B. 6, 221 ; 37, 1467). a- and /MMbenzyl-benzol melt at 
 86 and 78. 
 
 Bis-amido-benzyl-resorein (NH 2 C 6 H 4 .CH 2 ) 2 C 6 H 2 (OH) 2 , m.p. 213, 
 is formed as a by-product of the condensation of p-amido-benzyl 
 alcohol with resorcin by hot dilute sulphuric acid (C. 1903, I. 288). 
 
 p 2 -Dibenzo-hydryl-benzol C 6 H 4 (CHOHC 6 H 5 ) 2 , m.p. 120, from 
 o 2 -dibenzoyl-benzol by reduction with sodium amalgam. By the 
 action of mineral acids it easily passes into sym. diphenyl-phtlialane 
 
 (CH;-C 6 H 5 
 
 C 6 H 4 -^ ^>O , m.p. 96, with expulsion of H 2 0. This is also obtained 
 
 I CH< C 6 H 5 
 
 synthetically from the result of the action of C 6 H 5 MgBr upon phenol 
 phthalide by rejection of water and reduction (C. 1905, II. 137). 
 
 /CO P TT 
 
 o 2 -, m 2 -, and p 2 -Dibenzoyl-benzols c 6 H/XVr5 5 phthalo-phenones, 
 
 xL/vJ.L^girlg 
 
 phenylene-diphenyl ketones, m.p. 146, 100, and 160 respectively. 
 The ortho- and para-derivatives are produced by the oxidation of the 
 corresponding dibenzyl-benzenes (B. 9, 31). 
 
 The meta- and ^w0-compounds may be obtained from meta- and 
 para-phthalyl chlorides with benzene and A1C1 3 (B. 13, 320), whereas 
 the so-called ortho-phthalyl chloride yields diphenyl-phthalide. 
 
 l-Amido-2, 4-dibenzoyl-benzol C 6 H 3 [i]NH 2 [2, 4](COC 6 H 5 ) 2 , m.p. 
 138, is obtained in the form of its benzoyl compound, m.p. 156, by 
 heating one molecule aniline with three molecules benzoyl chloride by 
 intramolecular atomic displacement by way of dibenzoyl amido- 
 benzo-phenone (C. 1905, I. 444). 
 
 Dibenzoyl-mesitylene (CH 3 ) 3 [i, 3, 5]C 6 H(COC 6 H 5 ) 2 , m.p. 117, from 
 mesitylene, two molecules benzoyl chloride, and A1C1 3 , gives on oxida- 
 tion sym. and unsym. dibenzoyl-mesitylenic acid (C 6 H 5 CO) 2 C 6 H(CH 3 ) 2 
 COOH, m.p. 222 and 174, sym. and unsym. dibenzoyl-uvitinic acid 
 (C 6 H 5 CO) 2 C 6 H(CH 3 )(COOH) 2 , m.p. 262 and 211, and finally dibenzoyl- 
 trimesinic acid (C 6 H 5 CO) 2 C 6 H(COOH) 3 , m.p. 250 (C. 1902, II. 1181). 
 
 III. TRIPHENYL-METHANE GROUP. 
 
 Triphenyl-methane, tolyl-diphenyl-methane, and ditolyl-phenyl- 
 methane are the parent hydrocarbons from which originate the ros- 
 
TRIPHENYL-METHANE GROUP 577 
 
 anilin dyes, the malachite greens, the aurins, and phthale'ins, from 
 which they can be obtained by various transposition and decomposition 
 reactions. However, in no one of these instances do they constitute 
 the foundation material for the technical preparation of the above- 
 mentioned dyes. 
 
 i. Hydrocarbons. The methods of forming the triphenyl-methane 
 hydrocarbons are evident if one simply makes more general those 
 methods which are employed in the preparation of triphenyl-methane. 
 
 Triphenyl-methane CH(C 6 H 5 ) 3 , m.p. 92 and b.p. 358. It is 
 produced : 
 
 (1) By the action of benzal chloride upon mercury diphenyl (1872, 
 Kekule and Franchimont, B. 5, 907). 
 
 (2) From benzal chloride or benzo-trichloride and benzene (a) by 
 the action of zinc dust, (b) with aluminium chloride (B. 12, 976, 1468 ; 
 14, 1526). 
 
 (3) From chloroform or carbon tetrachloride and benzene, aided by 
 A1C1 3 (A. 194, 254 ; 227, 107 ; B. 18, R. 327). 
 
 (4) From chloroform or benzal chloride and phenyl-magnesium 
 bromide (C. 1906, II. 1262). 
 
 (5) By the action of P 2 O 5 at 140 (B. 7, 1204) upon benzo-hydrol and 
 benzene. 
 
 (6) From triphenyl-carbinol or its bromide by reduction (B. 37, 
 616, 1249 ; 44, 441). 
 
 (7) By the action of nitrous acid and alcohol upon di- and tri- 
 amido-triphenyl-methane sulphate (A. 206, 152). 
 
 The latter reaction is of the greatest fundamental importance in 
 demonstrating the connection between p-rosanilin and triphenyl- 
 methane. 
 
 Triphenyl-methane crystallised from benzene contains benzene of 
 crystallisation CH(C 6 H 5 ) 3 +C 6 H 6 , m.p. 75; and from thiophene, 
 pyrrol, and aniline it separates with thiophene (pyrrol, or aniline) of 
 crystallisation CH(C 6 H 5 ) 3 +C 4 H 4 S (B. 26, 853). It is oxidised to 
 triphenyl-carbinol, and is reduced with hydrogen and finely divided 
 nickelat22O totricyclo-hexyl-methane,b.p. 20 i4o(C.i9O9,I.i73),andby 
 hydriodic acid, and some red phosphorus at 280, to benzene and toluol. 
 When heated with potassium, it yields triphenyl-methane-potassium 
 (C 6 H 5 ) 3 CK, which combines with CO 2 to potassium-triphenyl acetate. 
 
 o-, m-, p - Methyl - triphenyl - methane, diphenyl -o-, m-, p-tolyl- 
 methane (C 6 H 5 ) 3 CH.C 6 H 4 .CH 3 , melt at 83, 62, and 71; from the 
 carbinols by reduction. The m-compound was obtained by the action 
 of nitrous acid and alcohol upon leucaniline sulphate (A. 194, 282 ; 
 cp. B. 37, 1245). The p-tolyl-diphenyl-methane is easily prepared 
 from benzo-hydrol and toluol, with tin tetrachloride (B. 37, 659). 
 
 Diphenyl-o-, m-, p-xylyl-methanes melt at 68, 61, and 92 ; they 
 have been obtained from benzo-hydrols with o-, m-, and p-xylol by 
 means of P 2 O 5 (B. 16, 2360). 
 
 Nitro-substitution Products. m- and p-Nitro-diphenyl-methane 
 NO 2 .C 6 H 4 .CH(C 6 H 5 ) 2 , m.p. 90 and 93, are obtained from m- and p- 
 nitre-benzaldehyde, benzene, and zinc chloride (B. 21, 188 ; 23, 1622). 
 
 When triphenyl-methane is dissolved in fuming nitric acid (sp. 
 gr. 1-5) it forms p-trinitro-phenyl-methane CH(CeH 4 [4]NO 2 ) 3 , which 
 melts at 206. Sodium alcoholate converts the nitro-compound into 
 VOL. II, 2 P 
 
57 8 ORGANIC CHEMISTRY 
 
 a deep violet-coloured sodium salt. It dissolves in alcoholic potassium 
 hydroxide with a violet colour (B. 21, 2476). On further nitration 
 with nitro-sulphuric acid we obtain O 3 p 3 -hexanitro-triphenyl-methane 
 CH[C 6 H 4 (NO 2 ) 2 ] 3 , m.p. 260 with decomposition, which, on reduction 
 with alcoholic Am sulphide, yields trinitro-triamido-triphenyl-methane 
 (B. 36, 2779). 
 
 p-Trinitro-diphenyl-m-tolyl-methane (NO 2 [4]C 6 H 4 ) 2 CH.C 6 H 3 [ 4 ]NO 2 
 [3]CH 3 . 
 
 Amido-derivatives are produced (i) by the reduction of the 
 corresponding nitro-bodies ; (2) by reduction of the corresponding 
 amido-carbinols, the colour-bases of the malachite green and rosanilin 
 groups, as the leuco-derivatives of which they are frequently designated ; 
 
 (3) by the condensation of benzo-hydrol or benzaldehyde and aniline 
 hydrochloride, or dimethyl-aniline hydrochloride, with P 2 O 5 or ZnCl 2 . 
 
 (4) Mixed diamido-triphenyl-methanes are also obtained as follows : 
 Benzylidene-anilines unite with anilines to form amido-benzo-hydril- 
 phenylamines : the latter, with aromatic amine salts, yield diamido- 
 triphenyl-methanes (C. 1900, II. 548) : 
 
 H CH NC H e, rH< /C 6 H 4 NH 2 C 7 H 7 NH, C H 5 CH/** 
 
 6 H 5 Ci *C 8 H 6 _ -_^ C 6 H 6CH\ NHC6H6 - HCI \C,H 6 NH 2 
 
 When oxidised with chloranile, or PbO 2 and hydrochloric acid, etc., 
 their salts change to those of the colour-bases to which malachite green 
 and rosanilin belong ; they are derived from triphenyl-carbinol. 
 
 o-Amino-triphenyl - methane (C ? H 5 ) 2 CHC 6 H 4 [2]HN 2 , m.p. 129, 
 from the corresponding amino-carbinol by reduction with zinc dust 
 and glacial acetic acid (B. 37, 3198). 
 
 m-Amino-triphenyl-methane (C 6 H 5 ) 2 CHC 6 H 4 [3]NH 2 , melting at 
 120, is obtained from m-nitro-triphenyl-methane (B. 21, 189). 
 
 p-Amino-triphenyl-methane, melting at 84, is formed (i) from 
 p-nitro-triphenyl-methane (B. 23, 1623) ; (2) from benzo-hydrol, aniline 
 hydrochloride, and zinc chloride (A. 206, 155) ; (3) from phenyl-benzo- 
 hydrylamine by heating with aniline chlorohydrate (B. 38, 1768). 
 
 p-Dimethyl-amido-triphenyl - methane (C 6 H 5 ) 2 CH.C 6 H 4 [4]N(CH 3 ) 2 , 
 melting at 132, is formed from benzo-phenone chloride and dimethyl- 
 aniline, as well as from benzo-hydrol and dimethyl-aniline with P 2 O 5 
 (A. 206, 113), as well as from benzo-phenone, dimethyl-aniline, and 
 zinc chloride (A. 242, 341). p-Aeetamido-triphenyl-methane melts at 
 176 (B. 24, 728). 
 
 p 2 -Diamido-triphenyl-methane C 6 H 5 .CH(C 6 H 4 [4]NH 2 ) 2 , melting at 
 139, -|- C 6 H 6 at 106, the parent substance of malachite green, is 
 obtained (i) from benzal chloride and aniline with zinc dust ; (2) from 
 benzaldehyde with aniline hydrochloride on heating with zinc chloride 
 to 120 (B. 15, 676), or by boiling benzaldehyde with aniline and 
 hydrochloric acid (B. 18, R. 334) ; (3) by reducing diamino-triphenyl- 
 carbinol chloride with zinc dust. The diacetyl derivative, m.p. 234, 
 s sparingly soluble. 
 
 P 2 - Tetramethyl - diamino - triphenyl - methane C 6 H 5 .CH[C 6 H 4 [4]N 
 (CH 3 ) 2 ] 2 , leuco-malachite green, is dimorphous, and crystallises in 
 flakes, melting at 93-94, or in needles, which melt at 102. The first 
 modification is obtained pure by crystallisation from alcohol, the second 
 from benzene. It is obtained by methylating p 2 -diamido-triphenyl- 
 
TRIPHENYL-METHANE GROUP 579 
 
 methane, as well as by the action of benzaldehyde upon dimethyl- 
 aniline. Technically, it is made by the condensation of benzaldehyde 
 and dimethyl-aniline with hydrochloric or sulphuric acid (formerly zinc 
 chloride or oxalic acid). By oxidation it becomes p 2 -tetramethyl- 
 diamido-triphenyl-carbinol, the basis of malachite green. 
 
 By heating with BrCN, leuco-malachite green yields dimethyl- 
 dicyano-diamido-triphenyl-methane [CH 3 N(CN)C 6 H 4 ] 2 CHC 6 H 5 , m.p. 
 163, which, on saponification with HC1, yields p 2 -dimethyl-diamino- 
 triphenyl-methane (CH 3 NH.C 6 H 4 ) 2 CHC 6 H 5 , m.p. 104 (B. 37, 637). 
 
 o- and m-Nitro-p 2 -diamido-triphenyl-methane are produced in the 
 condensation of o- and m-nitro-benzaldehyde with aniline sulphate by 
 means of zinc chloride. The m-body melts at 136 (B. 13, 671 ; 16, 
 1305)- 
 
 p-Nitro-p 2 -diamino-triphenyl-methane is obtained from p-nitro- 
 benzaldehyde, just as the o- and m-compounds are prepared. See 
 p-Leucaniline (B. 25, 676). 
 
 Benzaldehyde and the nitro-benzaldehydes condense with o- and 
 p-toluidin, just as they do with aniline and dimethyl-aniline (B. 18, 
 2094), whereas m-toluidin and m-derivatives of aniline only react 
 readily if the amido-group is methylated (B. 20, 1563). 
 
 Triamino-triphenyl-methanes result from the reduction of the nitro- 
 and nitro-amido-triphenyl-methanes and of the triamido-triphenyl- 
 carbinols. The latter are the rosanilin bases if the three amido- 
 groups occur in the p-position with reference to the C(OH) group. 
 Their reduction products are also called leucanilines. These are white 
 precipitates, and when oxidised yield the carbinols : 
 
 o, p 2 -Triamido-triphenyl-methane, or o-leucaniline, 
 and m, p 2 -Triamido-triphenyl-methane, or pseudo-leucaniline, 
 and p 3 -Triamido-triphenyl-methane, or para-leucaniline, 
 
 which, upon oxidation, yield dyestuffs. That from the o-body is 
 brown in colour, that from the m-body is violet, while that from the 
 p-compound is para-rosanilin. p-Triamido-triphenyl-methane is also 
 produced in the condensation of p-amino-benzaldehyde and aniline 
 with zinc chloride ; its tris-diazo-chloride CH(C 6 H 4 .N 2 C1) 3 , when boiled 
 with alcohol, forms triphenyl-amine. 
 
 p 3 -Triamido-diphenyl-m-tolyl-methane, leucaniline (NH 2 [4]C 6 H 4 ) 2 
 CH.C 6 H 3 [4](CH 3 ).NH 2 [3], is the leuco-compound corresponding to the 
 chief constituent of rosanilin obtained by the reduction of trinitro- 
 diphenyl-meta-tolyl-methane, and is also made by digesting the 
 fuchsine salts with ammonium sulphide, or zinc dust and hydrochloric 
 acid. By diazotising, and replacing the diazo-groups by hydrogen 
 (best effected by dissolving in concentrated sulphuric acid, conducting 
 nitrous acid into the same, and boiling with alcohol), leucaniline is 
 changed into diphenyl-m-tolyl-methane. 
 
 2. Carbinols are formed (i) by oxidising the triphenyl-methane 
 hydrocarbons, and their nitro- and amido-compounds, and by many 
 synthetic methods ; (2) from aryl-magnesium haloids, (a) with aromatic 
 carboxylic esters or benzo-phenones (B. 35, 3024 ; 36, 406 ; 37, 663, 
 990) : 
 
 C 6 H 5 COOCH 3 +2C 6 H 5 MgBrv . 
 
 C 6 H 5 COC 6 H 5 +C 6 H 5 MgBr_/~ ( C 6 H 5 )3<-( 
 
580 ORGANIC CHEMISTRY 
 
 (b) with other products, by the action of CO 2 , COS, COC1 2 , C1COOR 
 (B. 36, 1010, 3005, 3087, 3236) : 
 
 3 C 6 H 5 MgBr - ^-> (C 6 H 5 ) 3 C(OH). 
 
 (3) from triaryl-acetic acids by rejection of CO on treating with con- 
 centrated H 2 SO 4 (B. 37, 655) : 
 
 (C 6 H 5 ) 2 C(C 6 H 4 CH 3 )COOH - --> (C 6 H 5 ) 2 C(C 6 H 4 .CH 3 )OH. 
 
 Triphenyl-carbinol (C 6 H 5 ) 3 C.OH, m.p. 163, b.p. above 360. 
 o-, m-, and p-Tolyl-diphenyl-carbinol (C 6 H 5 ) 2 (C 6 H 4 .CH 3 )C.OH, m.p. 
 98, 65, and 74 (B. 37, 656, 992, 1245). Tri-p-tolyl-earbinol (CH 3 
 C 6 H 4 ) 3 .C.OH, m.p. 96 (B. 37, 3153). 
 
 Diphenyl-mono-biphenyl-carbinol (C 6 H 5 ) 2 C(OH).C 6 H 4 .C 6 H 5 , m.p. 
 136 ; phenyl-di-biphenyl-carbinol (C 6 H 5 .C 6 H 4 ) 2 C(OH)C 6 H 5 , m.p. 151 ; 
 tri-biphenyl-carbinol (C 6 H 5 .C 6 H 4 ) 3 C.OH, m.p. 208, see A. 368, 298. 
 
 The OH group of triphenyl-carbinol and its homologues is very 
 reactive. Triphenyl-carbinol is easily etherified by alcohols, forming 
 triphenyl-carbinol-methyl ether (C 6 H 5 ) 3 COCH 3 , m.p. 82. The ethers 
 are easily saponified with acids. With bisulphites we obtain salts of 
 triphenyl-methyl-sulphonic acids (C 6 H 5 ) 3 C.SO 3 Na ; with aniline we 
 obtain triphenyl-carbinol-aniline, while aniline chlorohydrate yields 
 p-amido-tetraphenyl-methane, and tetraphenyl-methane derivatives 
 are similarly formed with phenol and anisol. With sulphuric acid the 
 carbinols form coloured unstable acid sulphates, whose stability is 
 increased with the introduction of halogen or methoxylene into the 
 benzene nuclei of the carbinols (B. 38, 1156). Especially characteristic 
 are the easily crystallised perchlorates of the triphenyl-carbinols, which 
 are also intensely coloured (B. 43, 183). With pyridin and quinolin 
 also, triphenyl-carbinol produces saline compounds (B. 35, 4007). 
 
 Triphenyl-ehloro-methane, triphenyl-carbinol chloride (C 6 H 5 ) 3 CC1, 
 m.p. ni, is formed from carbinol by treatment with hydrochloric 
 acid in glacial acetic acid, with PC1 5 or with acetyl chloride (B. 36, 384, 
 3924) ; also on heating triphenyl-acetic chloride with concentrated 
 sulphuric acid, CO being eliminated. It is formed synthetically from 
 benzene and CC1 4 with aluminium chloride (cp. C. 1902, I. 463). 
 Triphenyl-bromo-methane, from triphenyl-methane in CS 2 with 
 bromine in sunlight (A. 227, no), or from the carbinol with glacial 
 acetic hydrobromic acid (B. 42, 3024). Triphenyl-iodo-methane, m.p. 
 132, by the action of iodine in CS 2 upon a solution of triphenyl- 
 methyl. Its solutions, when exposed to the oxygen of the air, eliminate 
 iodine, and form triphenyl-methyl peroxide. With excess of halogen 
 the triphenyl-halogen-methanes unite to form well-crystallised per- 
 haloids (C 6 H 5 ) 3 CBr.Br 5 , (C 6 H 5 ) 3 CBr.I 5 , (C 6 H 5 ) 3 CI.I 5 , etc. (B. 35, 1831). 
 
 The halogen is bound up in the triphenyl-halogen-methanes remark- 
 ably loosely. In many respects they behave like metallic salts, their 
 solutions in sulphurous acid, pyridin, and acetone conducting the 
 electric current (B. 43, 336). In the electrolysis of triphenyl-bromo- 
 methane in a solution of SO 2 , it is split up, just like a metallic salt, into 
 bromine, and the radicle triphenyl-methyl (C 6 H 5 ) 3 C, which is partly 
 transformed into the dimeric hexaphenyl-ethane (A. 372, n). On 
 
TRIPHENYL-METHANE GROUP 581 
 
 boiling with water the triphenyl-halogen-methanes are transposed into 
 triphenyl-carbinol. On treatment with silver acetate we obtain 
 triphenyl-carbinol acetate (C 6 H 5 ) 3 COCOCH 3 , m.p. 88 (B. 36, 3926) ; 
 with potassium cyanide we obtain triphenyl-aceto-nitrile. 
 
 Triphenyl-chloro-methane is colourless in the solid state, and dis- 
 solves in SO 2 with a yellow colour, being probably transposed into the 
 
 quinoid form (C 6 H 5 ) 2 C : C 6 H 4 <^. In agreement with this view, the 
 
 \(_xi 
 
 p 3 - tribromo - triphenyl - chloro - methane can be transformed, by 
 crystallisation, from sulphurous acid into the isomeric, and less 
 soluble, p 3 -monochloro-dibromo-triphenyl-bromo-methane with ex- 
 change of a bromine and chlorine atom, the following bases being 
 passed through (B. 42, 406) : 
 
 BrC 6 H 4 \ rn ri \C 6 H 4 % r 
 
 (BrC 6 H 4 ) 2 ^ (BrC 6 H 4 )/ 
 
 With metallic chlorides, such as A1C1 3 , ZnQ 3 , SnCl 4 , etc., triphenyl- 
 chloro-methane yields intensely coloured double compounds, which, 
 like the carbinol sulphates and perchlorates mentioned above, probably 
 belong to the quinoid type. With magnesium and ether, it forms the 
 very unstable triphenyl-methyl-magnesium chloride (C 6 H 5 ) 3 CMgCl. By 
 the action of zinc, or molecular silver, or copper, upon the benzene 
 solution of triphenyl-chloro-methane with the exclusion of air, we 
 obtain triphenyl-methyl and hexaphenyl-ethane respectively. By 
 heating above 280 triphenyl-chloro- and bromo-methane are con- 
 densed to diphenylene-phenyl-methane (C 6 H 4 ) 2 CHC 6 H 5 . 
 
 Triphenyl-methyl-amine, triphenyl-carbinol-amine (C 6 H 5 ) 3 C.NH 2 , 
 m.p. 103, is prepared by conducting dry ammonia gas into a benzene 
 solution of triphenyl-carbinol bromide, chloride, or iodide (B. 17, 442, 
 741 ; 35, 1827). 
 
 Triphenyl-methyl-aniline (C 6 H 5 ) 3 C.NHC 6 H5, m.p. 144, is also formed 
 from triphenyl-carbinol by heating with aniline in glacial acetic acid 
 (B. 17, 703, 746 ; 35, 3016). A derivative of triphenyl-methyl-amine 
 
 is the so-called diphenyl-benzyl-sultame C 6 H 4 /W^6H 5 ) 2 \ NH ^ mp 
 
 UL2jbo 2 / 
 
 210, formed besides phenyl-benzal-sultime in the condensation of 
 pseudo-saccharin chloride with benzene and A1C1 3 (B. 29, 2296). 
 
 Triphenyl-methyl-hydrazin (C 6 H5) 3 C.NHNH 2 , chlorohydrate, m.p. 
 133, is formed, besides hydrazo-triphenyl-methane, in the action of 
 hydrazin hydrate upon triphenyl-chloro-methane. With HNO 2 it 
 
 yields triphenyl-methyl-azide (C 6 H 5 ) 3 CN<^J, m.p. 64, a remarkably 
 
 stable ester of hydrogen nitride (B. 42, 3024). 
 
 Tripnenyl-methane-hydrazo-benzol (C6H 5 ) 3 CNHNHC 6 H 5 , m.p. 137, 
 from triphenyl-carbinol chloride or bromide with phenyl-hydrazin. It 
 is oxidised by HNO 2 to triphenyl-methane-azo-benzol (C 6 H 5 ) 3 CN : 
 NC 6 H 5 , m.p. 114 (B. 36, 1088). 
 
 Hydrazo-triphenyl-methane (C 6 H 5 ) 3 C.NHNH.C(C 6 H 5 ) 3 , m.p. 209, 
 from triphenyl-chloro-methane and hydrazin hydrate. By oxidation 
 with sodium hypo-bromite it decomposes by way of the very unstable 
 azo-triphenyl-methane into nitrogen and triphenyl-methyl. Bromine or 
 
582 ORGANIC CHEMISTRY 
 
 iodine converts it into triphenyl-bromo- and iodo-methane respectively, 
 or into the perhaloids (B. 42, 3020). 
 
 m- and p-Bromo-triphenyl-earbinol, m.p. 67 and 114, from m- and 
 p-bromo-benzoic ester and C 6 H 5 MgBr. p-Trichloro-triphenyl-carbinol, 
 m.p. 99, from p-chloro-iodo-benzol, p-chloro-benzoic ester, and 
 magnesium. p-Tri-iodo-triphenyl-carbinol, m.p. 163, from the tri- 
 diazonium sulphate of p-rosanilin with iodo-potassium iodide (B. 
 38, 585). 
 
 m- and p-Nitro-triphenyl-earbinol (C 6 H 5 ) 2 C(OH)C 6 H 4 NO 2 , m.p. 75 
 and 98 ; the p-compound is obtained pure from its chloride, the con- 
 densation product of p-nitro-benzo-phenone chloride with benzene 
 and A1C1 3 (B. 21, 190 ; 37, 604). 
 
 p 3 -Trinitro-phenyl-carbinol (NO 2 [4]C 6 H 4 ) 3 .C.OH, m.p. 171, is pre- 
 pared from p 3 -trinitro-phenyl-methane by the action of chromic acid 
 in glacial acetic acid. It yields p-rosanilin upon reduction. 
 
 Amido - triphenyl - carbinols. p 2 -Diamido - triphenyl - carbinol and 
 pg-triamido-carbinols, of this class, deserve special consideration. 
 p 2 -Tetramethyl-diamido-triphenyl-carbinol is the basis of malachite 
 green, and p 3 -triamido-triphenyl-carbinol that of p-rosanilin. The free 
 amido-carbinols are colourless. In contact with acids water is elimi- 
 nated and colour salts result. These are also formed by the direct 
 oxidation of the salts of the leuco-compounds, and pass into the latter 
 upon reduction. Thus p-leucaniline hydrochloride (i) yields, upon 
 oxidation, p-rosanilin chloride, from which colourless p 3 -triamido- 
 triphenyl-carbinol is separated by bases ; hydrochloric acid converts 
 this compound again into p-rosanilin chloride : 
 
 NH t [4]C 8 H 4 \ /C,H 4 [4]NH,HC1 ^_ 2 JL_ NH 1 [4]C,H 4 \ C /C.H 4 NH 1 C1 +_ Hcl NH 2 C.H 4 \ c /C,H 4 NH, 
 NH 1 [ 4 ]C.H i /*'\H ^NH.MC.H/^ ' l^T^ NH.C.H,/ \OH 
 
 Only these mono-, di-, and triphenyl-carbinols are capable of forming 
 coloured salts with expulsion of water, which contain at least one 
 amido-group in the p-position. Dyestuffs are only formed if two 
 p-amido-groups are present. 
 
 With a careful transposition of the dye salts with soda solution, 
 the first phase is the production of more or less unstable methylene- 
 quinone-imide Ar 2 C : C q H 4 : NR, or Ar 2 C : C 6 H 4 : NR 2 OH (cp. Methy- 
 lene quinones), and in a second phase they either attach or 
 transpose water and form amino-carbinols. 
 
 These reactions, occurring even in the simplest p-amino-carbinols, 
 are similarly repeated in the p-oxy-triphenyl-carbinols. According to 
 this we may regard diphenyl-quino-methane as the foundation sub- 
 stance for the dyestuffs of the triphenyl-methane series, which there- 
 fore can be termed fuchsone on account of the most important dye 
 (B. 37, 2848) : 
 
 (C 6 H 5 ) 2 C : C 6 H 4 : O (C 6 H 5 ) 2 C : C 6 H 4 : NH (C 6 H 5 ) 2 C : C 6 H 4 : NH 2 C1 
 Fuchsone [Fuchsone-imine] Fuchsone-imonium chloride. 
 
 p-Amino-triphenyl-carbinol HO.C(C 6 H 5 ) 2 .C 6 H 4 NH 2 , from its acetyl 
 derivative formed by oxidation from acetamido-triphenyl-methane 
 with PbO 2 . With HC1 it first forms the feebly coloured or colour- 
 less salts HO.C(C 6 H 5 ) 2 C 6 H 4 NH 2 .HClland C1C(C 6 H 5 ) 2 C 6 H 4 NH 2 .HC1, 
 
TRIPHENYL-METHANE GROUP 583 
 
 which, on heating, expel H 2 O or HC1, and form the strongly coloured 
 salts of the bases free from oxygen. The latter, anhydro-p-amido- 
 triphenyl-carbinol (fuchsone-imine) , is dimolecular and colourless in the 
 free state [(C 6 H 5 ) 2 C.C 6 H 4 : NH] 2 . Its salts are also obtained from the 
 condensation products of p-amido-benzo-phenone with phenyl-mag- 
 nesium bromide (B. 37, 597). 
 
 p-Anilino-triphenyl-carbinol, colourless, is formed from the anhydro- 
 base, diphenyl-methylene-quinone-phenyl-imine, fuchsone-anile (see 
 above) (C 6 H 5 ) 2 C : C 6 H 4 : NC 6 H 5 , red prisms, melting at I33-I38, by 
 addition of water. For forming the latter, diphenyl-p-anisile-carbinol- 
 anilide (C 6 H 5 ) 2 C(NHC 6 H 5 )C 6 H 4 OCH 3 , with organic acids like benzoic 
 acid (B. 37, 608). 
 
 p-Dimethyl-amino-triphenyl-earbinol (CH 3 ) 2 N.C 6 H 4 C(OH) (C Q U 5 ) 2 , 
 m -P- 93 > from p-dimethyl-amino-phenyl-magnesium bromide with 
 benzo-phenone, or benzo-phenone chloride, dimethyl-aniline, and ZnCl 2 
 (B. 36, 4296 ; 37, 2857). 
 
 o-Amino-triphenyl-earbinol, m.p. 121, from anthranilic ester and 
 C 6 H 5 MgBr. On prolonged heating it expels water and forms phenyl- 
 acridin. The chlorohydrate of carbinol chloride, on treatment with 
 pyridin, gives an anhydro-compound (C 19 H 15 N) 2 analogous to the 
 p-compound, m.p. 250 with decomposition (B. 37, 3191). 
 
 m-Amino-triphenyl-earbinol, m.p. 155 (B. 21, 190). 
 
 p 2 -Diamino-triphenyl-carbinol (NH 2 C 6 H 4 ) 2 C(OH)C 6 H 5 , colourless 
 crystals, best obtained by oxidising the diaceto-diamino-triphenyl- 
 methane with MnO 4 , saponification and purification over methyl ether, 
 m.p. i6i-i63. On heating it splits off water and passes into the 
 unstable methylene-quinone-imine base (amino-fuchsone-imine), the 
 salts of which are purple- violet dyestuffs, resembling fuchsine (B. 
 37,2859). 
 
 p 2 -Dimethyl-diamino-triphenyl-carbinol (CH 3 NH.C 6 H 4 ) 2 C(OH)C 6 H 5 , 
 m.p. 95, is formed by saponifying the cyanated carbinol [CH 3 N(CN) 
 C 6 H 4 ] 2 C(OH)C 6 H 5 , generated from the corresponding triphenyl-methane 
 derivative by oxidation with permanganate in acetone solution (B. 
 37, 641). 
 
 p 2 -Tetramethyl-diamido-triphenyl-carbinoI C 6 H 5 .C(OH)[C 6 H 4 [4]N 
 (CH 3 )2] 2 , melting at 132, crystallises from benzene in colourless forms. 
 It is obtained from its salts (malachite green) by precipitation with the 
 alkalies and by oxidising an alcoholic solution of p 2 -tetramethyl- 
 diamido- triphenyl-methane with chloranile (A. 206, 130), and from 
 p-dimethyl-amido-phenyl-magnesium bromide with benzoic acid ester 
 (B. 36, 4296). 
 
 Methyl ether C t H,C(OCH 8 )[C i H t N(CH t )J f , m.p. 151 (B. 33, 3356 ; 
 37, 2867). lodo-methylate C 6 H5C(OCH 8 )[C 6 H 4 N(CH 8 ) 8 I] a +2H 2 O is 
 obtained by heating p 2 -diamido-triphenyl-carbinol and p 2 -tetramethyl- 
 diamido-triphenyl-carbinol with methyl iodide and methyl alcohol. 
 
 The free base yields almost colourless solutions with acids in the 
 cold ; upon standing, and more rapidly on heating, the solution acquires 
 a green colour and then contains the green salts malachite greens of 
 the anhydro-base of the carbinol (B. 12, 2348 ; 33, 298). 
 
 Malachite green, bitter almond oil green C 6 H 6 . C<^H 4 N(CH 3 ) 2 ^ 
 
 ( \Lx<jJtl4JN(Url3J2^1 
 
 hydrochloride of the anhydro-base, is produced when zinc chloride 
 
584 ORGANIC CHEMISTRY 
 
 acts upon a mixture of benzo-trichloride and dimethyl-aniline, or 
 upon a mixture of benzoyl chloride and dimethyl-aniline (A. 206, 137). 
 
 Technically, leuco-malachite green is first prepared, and its hydro- 
 chloride then oxidised with lead peroxide. While benzoic acid cannot 
 be condensed with dimethyl-aniline, ortho-methylated benzoic acids 
 with tertiary anilines give green dyes corresponding to malachite 
 green by a clean reaction (C. 1899, I. 1089). 
 
 Malachite green, characterised by its strong colouring power, is 
 usually supplied commercially in the form of its zinc chloride double 
 salt (C 23 H 25 N 2 Cl) 3 .2ZnCl 2 +2H 2 O, or its oxalate (C 23 H 25 N 2 ) 2 3C 2 O 4 H 2 . 
 
 History. Malachite green, or bitter almond oil green, was obtained 
 in 1877 by O. Fischer, in the oxidation of p 2 -tetramethyl-diamido-tri- 
 phenyl-methane. He obtained the latter compound by condensing 
 benzaldehyde with dimethyl-aniline. Doebner (1878) showed how 
 malachite green could be prepared from benzo-trichloride and dimethyl- 
 aniline. 
 
 Brilliant green, solid green, new Victoria green, is the tetra-ethyl 
 derivative, corresponding to malachite green, which is made from 
 diethyl-aniline and benzaldehyde (B. 14, 2521). The colour is more 
 yellow- tinted than that of malachite green. 
 
 Acid green is a dye obtained from benzaldehyde and benzyl-ethyl 
 aniline by condensation, oxidation, and sulphonation. The sulpho- 
 groups are in the benzyl residue (B. 22, 588). 
 
 Nitro-malachite greens have been prepared with o-, m-, and p-nitro- 
 benzaldehydes and dimethyl-aniline as the foundation substances 
 (B. 15, 682). o-Amino-malaehite green is a blue dye. The base is 
 formed from the urethane of o-amino-lemo-malachite green COOC 2 H 5 . 
 NH[2]C 6 H 4 CH[C 6 H 4 : NfCH^Jg by oxidation and saponification (B. 36, 
 2776). Further substituted malachite greens, see B. 39, 2041. 
 
 o, p'-, m, p'-, o, m'- and m, m'-Tetramethyl-diamino-triphenyl-ear- 
 binol, m.p. 170, 140, 184, and 129 respectively, have been obtained 
 from the corresponding amido-benzo-phenones by transformation 
 with C 6 HsMgBr or (CH 3 ) 2 NC 6 H 4 Mg (A. 354, 195). 
 
 Triamido-triphenyl-earbinols. p 2 - Triamido-triphenyl-carbinol, p 3 - 
 triamido-diphenyl-m-tolyl-carbinol, and their methyl, ethyl, benzyl, and 
 phenyl derivatives, are of the highest importance in the coal-tar colour 
 industry. Their salts, with one equivalent of acid, hydrochloric or 
 acetic, constitute the group of rosanilin dyes in the more restricted 
 sense. Like malachite green, the rosanilin dye substances are free 
 from carbinol oxygen, as the salt formation is accompanied by an 
 intramolecular anhydride formation. The carbinols separated from 
 these salts by alkalies are colourless, but turn red on exposure to the 
 air. Careful treatment of p-rosanilin with sodium hydroxide yields 
 first a polymeride of the methylene-quinone-imine base (of p z -diamino- 
 fuchsone-imine, free from oxygen) in feebly tinted needles. On heating 
 p 3 -triamino-triphenyl-carbinol in a current of hydrogen to 200, a base, 
 also free from oxygen, forms as a red amorphous mass, which, with 
 acids, regenerates para-rosanilin quantitatively (B. 37, 1183, 2867). 
 This process may be represented as follows : 
 
 (NH 1 C.H 4 ),C(OH)C.H 4 NH, + > [(NH 2 C,H 4 ),C : C.H 4 : NH]x < > (NH,C,H 4 ) S C : C,H 4 : NH,C1. 
 
 Fuchsine is the dyestuff produced in the oxidation of a mixture of 
 
TRIPHENYL-METHANE GROUP 585 
 
 aniline, o-toluidin, and p-toluidin. It is the so-called red oil. Rosanilin 
 is the chief ingredient of fuchsine. It is the hydrochloride or acetate 
 of anhydro-p$-triamido-diphenyl-m-tolyl-carbinol C 2oH 19 N 3 . H Cl -f 4H 2 O 
 or C 20 H 19 N 3 .C 2 H 4 O 2 . The mon-acid salts combine with two addi- 
 tional equivalents of acid, forming yellowish-brown coloured salts, 
 which water decomposes into the stable mon-acid salts with intense 
 colours. These are applied as dyes. They are mostly readily soluble 
 in water and alcohol, and crystallise in metallic greenish crystals. 
 Their solutions are carmine-red in colour, and stain animal tissue 
 directly violet-red, while vegetable fibre (cotton) must first be mor- 
 danted (tannin). 
 
 The mono- and tri-acid salts of rosanilin, on taking up four mole- 
 cules HC1, NH 3 , or H 2 O, become colourless additive compounds, which 
 easily split off the added substances and reproduce the dyes (A . Chim. 
 Phys. 8, 7, 195). 
 
 Fuchsine combines with sulphurous acid, forming the readily 
 soluble, colourless fuchsine- sulphurous acid. 
 
 Aldehydes impart a red colour to this solution, which serves as a 
 reagent for them. 
 
 Oxidants used with red oil are stannic chloride (Verguin, 1859), 
 mercurous and mercuric nitrates, arsenic acid at i8o-2OO (Medloc, 
 Nicholson, Girard, and de Laire, 1860) ; nitro-benzol with a little 
 ferrous chloride or ammonium vanadate at i8o-i90, when the half 
 of the red oil is applied as hydrochloride (Coupier, 1869 ; cp. B. 6, 
 25, 423, 1072). 
 
 In the arsenic acid method the fuchsine is obtained in the form of 
 arsenites, which are then converted into the chlorohydrate or acetate, 
 and obtained free from arsenious acid by recrystallisation. 
 
 The nitro-benzol method yields immediately a fuchsine which is not 
 poisonous. The nitro-benzol only acts as an oxidant, without entering 
 into the fuchsine formation at all. 
 
 Fuchsine is not formed either from aniline or from p-toluidin, or 
 from o-toluidin alone. Even a mixture of aniline with o-toluidin is 
 not oxidised to fuchsine. However, not only a mixture of aniline 
 with o- and p-toluidin yields fuchsine, but in the oxidation of a mixture 
 of aniline and p-toluidin a dye, with the properties of fuchsine, called 
 para-rosanilin, is produced. This is also present in small amount in 
 the fuchsine made from aniline and o- and p-toluidins ; whereas the 
 principal constituent of ordinary fuchsine consists of the next higher 
 homologue of para-rosanilin, namely, rosanilin (B. 13, 2204). 
 
 By-products in the Formation of Fuchsine. The fuchsine solution 
 contains, in addition to 34 per cent, of fuchsine, other violet and brown 
 dyes : mauvanilin, violanilin, substances belonging probably to the 
 indulins, and other less thoroughly investigated substances, as well as 
 slight amounts of a yellow acridin dye, known as phosphin or chrysanilin. 
 
 History of the Recognition of the Constitution of Rosanilin and Para- 
 rosanilin. A. W. Hofmann was the first person to engage in a scientific 
 study of fuchsine. He began his investigations in the sixties, and was 
 led, as a consequence, to present a formula for fuchsine and its funda- 
 mental dye-base. He became acquainted with numerous derivatives 
 of fuchsine, especially the methyl and ethyl violet fuchsines. He 
 assumed that the nitrogen atoms held together the radicles in the 
 
586 ORGANIC CHEMISTRY 
 
 fuchsine molecule. However, Kekule (1867) argued for the possibility 
 that the methyl groups of the toluidin molecules, necessary for the 
 production of fuchsine, afforded the connection. K. Zulkowsky (1869) 
 assumed the presence of three amido-groups in fuchsine, and considered 
 it a derivative of a hydrocarbon with the formula C 18 H 34 . Gradually, 
 however, the conviction grew that fuchsine sprang from a higher 
 aromatic hydrocarbon. This idea had its basis or origin in the experi- 
 ments of Wanklyn, Caro, Graebe, Dale, Schorlemmer, and others, 
 which, in the main, established the relationship of fuchsine to rosolic 
 acid. The " keystone to that extended series of experimental and 
 speculative investigations " was the conversion (1878) of para-rosanilin, 
 prepared by the oxidation of aniline and p-toluidin, into triphenyl- 
 methane. This was the work of Emil and Otto Fischer. The hydro- 
 carbon prepared by them from rosanilin, the chief constituent of 
 fuchsine, proved to be diphenyl-m-tolyl-methane. 
 
 Triphenyl-methane (4) is formed in the decomposition of the tri- 
 diazo-sulphate of para-leucaniline with alcohol. In the diagram the 
 formula of the tridiazo-chloride (3) of para-leucaniline (2) is used for 
 the sake of simplicity. Concentrated nitric acid converts triphenyl- 
 methane into p 3 -trinitro-triphenyl-methane (5), which, upon reduction, 
 yields p 3 -triamido-triphenyl-methane or para-leucaniline (2). The 
 latter, by oxidation, is converted into p 3 -trinitro-triphenyl-carbinol (6). 
 On oxidising para-leucaniline with arsenic acid, or by reducing p 3 -tri- 
 nitro-phenyl-carbinol with acetic acid and zinc dust, para-rosanilin 
 (i) results. The following diagram illustrates this series of reactions, 
 which were carried out, beginning with rosanilin itself (A. 194, 242) : 
 
 (I)' /C 8 H 4 [ 4 ]NH 2 (2) /C 6 H 4 [ 4 ]NH 2 .HC1 (3) /C 6 H 4 [ 4 ]N:N.C1 
 
 ^-C 6 H 4 [ 4 ]NH 2 2H CH(-C 6 H 4 [ 4 ]NH 2 .HC1- 
 
 ^C 6 H 4 [ 4 ]NH.C1 
 
 2HC1 
 
 (6) /C a H 4 [ 4 ]NO t 
 C(OH) f-C a H 4 [ 4 ]N(V 
 
 \C 6 H 4 [ 4 ]NH 2 .HC1 
 
 (5) /C 6 H 4 [ 4 ]N0 2 
 CHf-C 6 H 4 [ 4 ]N0 2 
 
 CH^ C 6 H 4 [ 4 ]N:N.C1 
 
 \C 6 H 4 [ 4 ]N:N.C1 
 
 (4) 
 CH-C 6 H 
 
 C 6 H 4 [ 4 ]N0 2 \C 6 H 4 [ 4 ]N0 2 \C 6 H 
 
 Para-rosanilin is produced by oxidising a mixture of aniline and 
 p-toluidin according to the arsenic acid or nitro-benzol method. The 
 reaction may be imagined to proceed in that a molecule of p-toluidin 
 is oxidised to p-amido-benzaldehyde ; the latter then condenses with 
 two molecules of aniline to para-leucaniline or p 3 -triamido-triphenyl- 
 methane, from which, finally, para-rosanilin results by oxidation. 
 
 When working with small quantities, the most convenient way of 
 oxidising aniline and p-toluidin to para rosanilin consists in using 
 mercuric chloride (B. 24, 3552). An interesting formation of para- 
 rosanilin is that of heating aniline with carbon tetrachloride to 230, 
 when the latter furnishes the linking carbon atom. The hydro-iodide 
 of para-rosanilin results by using iodoform CHI 3 . 
 
 Para-rosanilin is further formed by the reduction of p 3 -trinitro- 
 triphenyl-carbinol (see above) ; by heating y 3 -nitro-diamido-triphenyl- 
 methane with ferrous chloride (B. 15, 678) ; triamido-triphenyl-car- 
 binol is also formed by moderated reduction of p-nitro-diamido- 
 triphenyl - methane, inasmuch as the diamido - diphenyl - methane- 
 phenyl-hydroxylamine (C 6 H 4 NH 2 ) 2 CH.C 6 H 4 .NHOH, formed at first, 
 
TRIPHENYL-METHANE GROUP 587 
 
 rearranges itself (B. 29, R. 32). Cp. also the action of NaOH upon nitro- 
 diamido-triphenyl-methane (C. 1897, II. 416) ; it is also obtained from 
 formaldehyde, aniline, and phenyl-hydroxylamine (C. 1897, II. 1064) ; 
 and, further, by heating p-diamido-diphenyl-methane with aniline and 
 some oxidising agent (B. 25, 302) ; by heating p-nitro-benzal chloride 
 with aniline (B. 18, 997) ; and by heating aurin to 120 with aqueous 
 ammonia (B. 10, 1016, 1123). 
 
 Nitrous acid converts it into auria Triphenyl-carbinol results 
 when para-rosanilin diazo-chloride is decomposed with finely divided 
 copper (B. 26, 2225). At i8o-20O para-rosanilin is converted, by 
 concentrated hydriodic acid, into aniline and p-toluidin. Evidence 
 favouring the p-position of the two amido-groups is found in the con- 
 version of p-rosanilin, by boiling hydrochloric acid, into p 2 -diamido- 
 benzo-phenone, which is also obtained from p-diamido-triphenyl- 
 methane, the condensation product of benzaldehyde with aniline. 
 Para-leucaniline, the reduction product from para-rosanilin, is also 
 formed by the reduction of p 3 -nitro-diamido-triphenyl-methane. The 
 p-position of the three groups in the latter compound follows from the 
 fact that it is produced by the same condensation reaction from p-nitro- 
 benzaldehyde and aniline by which p-diamido-triphenyl-methane is 
 made from benzaldehyde and aniline. 
 
 The rosanilin salts give a deeper blue shade than the salts of para- 
 rosanilin (B. 15, 680). 
 
 Homologous rosanilins have been prepared by the oxidation of a 
 mixture of aniline and unsym. meta-xylidin (B. 15, 1543), by condensa- 
 tion of p-nitro-benzaldehyde with o-toluidin, reduction and oxidation 
 of the resulting condensation product (B. 15, 679), and by the condensa- 
 tion of p-nitro-dimethyl-amido-benzo-hydrol with m-toluidin, etc. 
 (B. 24, 553). 
 
 Rosanilin-sulphonie acid, acid fuchsine, fuchsine S, is produced in 
 the action of fuming sulphuric acid at 120 upon rosanilin. Nucleus- 
 substituted fuchsines, see C. 1909, II. 362. 
 
 Alkylie Para-rosanilins. The introduction of methyl residues into 
 the amido-groups of rosanilin produces violet dyes methyl violet. The 
 violet colour assumes a deeper blue tint with the increase of methyl 
 groups. These dyes are made by methylating para-rosanilin and by 
 oxidising dimethyl-aniline. The methyl violets are reduced to leuco- 
 compounds when they are heated with ammonium sulphide to 120. 
 Boiling hydrochloric acid resolves them into dimethyl-aniline and 
 methylated p-diamido-benzo-phenones (B. 19, 108). 
 
 Hexamethyl-para-rosanilin, crystal violet [(CH 3 ) 2 N.C 6 H4] 2 .C=HC 6 
 =N(CH 3 ) 2 C1, is distinguished from the lower methyl derivatives by 
 great power of crystallisation. It forms one of the principal con- 
 stituents of methyl violet, and is produced (i) by the condensation 
 of p 2 -tetramethyl-diamido-benzo-phenone and dimethyl- aniline with 
 dehydrating agents : 
 
 (2) By heating dimethyl-aniline with COC1 2 and A1C1 3 or ZnCl 2 
 (B. 18, 767 ; R. 7). Formic acid, formic ester, chloro-carbonic ester, 
 perchloro-methyl-mercaptan, CSC1 2 , etc., act the same as phosgene 
 
588 ORGANIC CHEMISTRY 
 
 (B. 19, 109) ; (3) by oxidation of p 2 -tetramethyl-diamido-diphenyl- 
 methane with dimethyl-aniline ; (4) by heating its methyl chloride or 
 iodide to no-i2O ; (5) by oxidising its leuco-base. 
 
 P 3 - Hexamethyl - triamido - triphenyl - carbinol, crystal - violet base 
 C(OH) [C 6 H 4 [4]N(CH 3 ) Jg, melts at 195. It is also formed by condensa- 
 tion of p-dimethyl-phenyl-magnesium bromide with p 2 -tetramethyl- 
 diamido-benzo-phenone (B. 36, 4297). Tribromo-hydrate, see B. 
 33, 753- 
 
 P 3 - Hexamethyl - triamido - triphenyl - methane, leuco-crystal violet 
 CH[C 6 H 4 [4]N(CH 3 ) 2 ] 3 , melting at 173, results by the reduction of 
 crystal violet, by the condensation of ortho-formic ester and dimethyl- 
 aniline with ZnCl 2 , and by the condensation of p 2 -tetramethyl-diamido- 
 benzo-hydrol with dimethyl- aniline. Also by condensation of prussic 
 sesqui-chlorohydrate with dimethyl-aniline, by way of tetramethyl- 
 diamido-benzo-hydrylamine (C. 1900, I. 239). 
 
 Methyl violet is a mixture of hexamethyl-para-rosanilin with lower 
 methylated derivatives (B. 19, 107). It is produced in oxidising 
 dimethyl-aniline, alone or when mixed with monomethyl-aniline, with 
 iodine or chloranile, copper sulphate or chloride. When copper chloride 
 is used it is advisable to add acetic acid or phenol. 
 
 Pentamethyl violet C 19 H 12 N 3 (CH 3 ) 5 HC1 is formed by oxidising 
 p 3 -pentamethyl-triamido-triphenyl-methane [(CH 3 ) 2 NC 6 H 4 ] 2 CH.C 6 H 4 
 [4]NH.CH 3 , melting at .116. The latter can be isolated from the 
 reduction-product of commercial methyl violet, a mixture of penta- 
 and hexamethyl violet, by means of the acetyl derivative. This, when 
 oxidised with acetyl-pentamethyl-rosanilin, yields a green dyestuff 
 (B. 16, 2906). 
 
 Tetramethyl violet is formed by oxidising p 3 -amido-tetramethyl- 
 diamido-triphenyl-methane, melting at 152. The latter is a tetra- 
 methyl-para-leucaniline NH 2 [4]C 6 H 4 CH[C 6 H 4 [4]N(CH 3 ) 2 ] 2 , produced 
 in the reduction of p-nitro-malachite green. Its acetyl derivative, like 
 that of pentamethyl-leucaniline, yields a green dye upon oxidation. 
 
 Methyl green, methyl chloride of hexamethyl-para-rosanilin chloride 
 
 H *^-j N ^ CH ^ci, is produced when methyl chloride 
 
 acts upon an alcoholic solution of methyl violet heated to 40, sodium 
 hydrate being gradually added. 
 
 Alkylated Rosanilins. When rosanilin is heated with methyl 
 iodide, methyl chloride, ethyl iodide or chloride, and methyl or 
 ethyl alcohol, three amide hydrogen atoms are replaced by methyl 
 or ethyl radicles. The methyl base yields reddish-violet-coloured salts, 
 and the ethyl base pure violet (Hofmann's violet, dahlia) ; these 
 dissolve with difficulty in water, but dissolve easily in alcohol. 
 
 The violet dyes, by the addition of more methyl or ethyl groups, 
 yield tetra - alkylic rosanilin iodides, which are capable of adding 
 another molecule of methyl or ethyl iodide and forming iodine greens 
 i.e. iodo-methylate of tetramethyl-rosanilin iodide C 20 H 16 (CH 3 ) 4 N 3 I. 
 CH 3 I+H 2 O, which has been displaced in the dye industry by methyl 
 green (see B. 28, 1008). 
 
 Aldehyde green (Usebe, /. pr. Ch., 92, 337), another green rosanilin 
 dye, has been prepared by heating rosanilin with aldehyde and sul- 
 
TRIPHENYL-METHANE GROUP 589 
 
 phuric acid, and by further action of sodium hyposulphite. The most 
 recent opinion is that in this reaction an aniline group has been changed 
 to quinaldin, while the other two groups have occasioned the forma- 
 tion of aldol-aniline residues, which latter then add sulphur, just as is 
 done by aldol-aniline itself (cp. B. 24, 1700 ; 29, 60). 
 
 Phenylated para-rosanilins. Just as methyl violet is prepared from 
 dimethyl-aniline by means of COC1 2 , etc., so 
 
 Diphenylamine blue can be obtained by heating diphenylamine with 
 carbon hexachloride C 2 C1 6 or oxalic acid to 120. It is identical with 
 triphenyl-para-rosanilin C(OH)(C 6 H 4 .NH.C 6 H 5 ) 3 (B. 23, 1964), obtained 
 by the action of aniline upon para-rosanilin. By heating trianisyl- 
 carbinol with aniline and benzoic acid we obtain the benzoate of the pure 
 dye base ; the latter is called dianilino-fuchs one-anile (C 6 H 5 NH.C 6 H 4 ) 2 C : 
 C 6 H 4 : NC 6 H 5 ; it is a black crystalline powder, m.p. 238, which on 
 taking up water yields the colourless p 3 -trianilino-triphenyl-earbinol, 
 and, by reduction, trianilino-triphenyl-methane (B. 37, 2870). 
 
 At present it is only the sodium salts of its mono- and disulpho- 
 acids which are applied as alkali blue and water blue in dyeing. 
 
 Perchloro-formic ester CC1O 2 CC1 3 , in a similar manner converts 
 diphenyl-methylamine (C 6 H 5 ) 2 N.CH 3 into trimethyl-triphenyl-para- 
 
 rosanilin C(OH)(c,H 4 .N<f^ ) (B. 19, 278). Phosgene converts 
 
 \ \CxgJrl 6 /3 
 
 triphenylamine into the hydrochloride of hexaphenyl-para-rosanilin 
 C(OH)[C 6 H 4 .N(C 6 H 5 ) 2 ] 3 (B. 19, 758). Tricarbazol-earbinol C(OH) 
 (C 12 H 7 NH) 3 (B. 20, 1904), is produced by heating together carbazol 
 or diphenylimide and oxalic acid. It is analogous to the triphenyl- 
 amine derivative. 
 
 Phenylated rosanilins are obtained by heating rosanilin hydro- 
 chloride with aniline or toluidins, or the free base with aniline and some 
 benzoic acid. The triphenyl-rosanilin hydroehloride C 20 H 16 (C 6 H 5 ) 3 N 3 . 
 HC1 appeared in commerce as aniline blue, a bluish-brown crystalline 
 powder, with copper lustre, soluble in alcohol but not in water. To 
 dissolve it in the latter, sulpho-salts are prepared, which exhibit different 
 shades of blue (soluble blue), corresponding to the number of sulpho- 
 groups in them. At present diphenylamine blue, and other dyes, have 
 taken its place. Diphenylamine results on distilling triphenyl- 
 rosanilin. 
 
 By converting rosanilin, by means of the tridiazo-compound, into 
 the trihydrazin derivative, there results roshydrazin C(OH)(C 6 H 5 .NH. 
 NH 2 ) 3 ; this, by condensation with aldehydes and ketones, yields red 
 and blue dyestuffs (B. 20, 1557). 
 
 Other hexamethyl-triamino-triphenyl-carbinols have been obtained 
 by transposition of the dimethyl-amido-benzoic esters with dimethyl- 
 aniline-magnesium iodide (CH 3 ) 2 NC 6 H 4 MgI (A. 354, 200). 
 
 3. Phenol Derivatives of the Triphenyl-methanes. The phenol deriva- 
 tives of the triphenyl-methanes are produced (i) from the correspond- 
 ing amido-compounds through the diazo-derivatives ; (2) by condensa- 
 tions similar to those of the amido-compounds if phenols be substituted 
 for the anilines ; (3) by the reduction of the phenol-carbinols into 
 which they are changed by oxidation. 
 
 Monoocy-triphenyl-methanes. o-Oxy-triphenyl-methane (C 6 H 5 ) 2 CH. 
 C G H 4 [2]OH, m.p. 124, from o-amido-triphenyl-methane (A. 241, 367) 
 
590 ORGANIC CHEMISTRY 
 
 or the carbinol by reduction. m-Oxy-triphenyl-methane, m.p. 106 (A. 
 354, 171). p-Oxy-triphenyl-methane, m.p. no , and o-kresyl-diphenyl- 
 methane (C 6 H 5 ) 2 CHC 6 H 3 [3]CH 3 [4]OH, m.p. 100, from the carbinols 
 or from benzo-hydrol with phenol and o-cresol respectively and 
 SnCl 4 (B. 35, 3137 ; 36, 356 1). By condensation of salicyl-aldehyde 
 and anisaldehyde, with aniline sulphate, or dimethyl-aniline, and ZnCl 2 , 
 oxy-diamido-triphenyl-methanes have been obtained (B. 14, 2522 ; 16, 
 
 1307). 
 
 The di- and trioxy-triphenyl-methanes yield, on oxidation, di- and 
 triphenol-carbinols, which, as a rule, possess the character of dye- 
 substances. Carbinols in which two benzene nuclei are hydroxylated, 
 and which correspond to the malachite-green compounds, are termed 
 benze'ins, and the corresponding dioxy-triphenyl-methanes, leuco- 
 benzelns ; whereas the derivatives with three hydroxylated benzene 
 nuclei are called aurins or rosolic acids, while corresponding trioxy- 
 triphenyl-methanes are designated as leucaurins or leuco-rosalic acids. 
 iPg-Dioxy-triphenyl-methane, leuco-benze'in, leuco-benzaurin C 6 H 5 . 
 CH(C 6 H 4 [4]OH) 2 , m.p. 161, is obtained (i) from p 2 -diamido-triphenyl- 
 methane (A. 206, 153), (2) by reducing benzaurin (A. 217, 230), as 
 well as (3) by the condensation of benzaldehyde and phenol with 
 sulphuric acid (B. 22, 1944). It melts at 161. 
 IfeDioxy-dimethyl-triphenyl-methane C 6 H 5 CH[C 6 H 3 (OH)CH 3 ] 2 melts 
 at*i7o (A. 257, 70). Phenyl-dithymol-methane melts at 166. 
 
 See B. 24, R. 562, for the condensation of m-nitro-benzaldehyde 
 with phenols. 
 
 P 3 - Trioxy - triphenyl - methane, leueaurin [triphenylol - methane] 
 CH(C 6 H 4 [4]OH) 3 , is obtained in the reduction of aurin, its carbinol 
 anhydride, by means of zinc dust and sodium hydrate or acetic acid. 
 It crystallises in colourless needles, which become coloured on exposure 
 to the air (A. 166, 286 ; 194, 136 ; 202, 198). The triacetate melts at 
 138 (B. 11, 1117). 
 
 p 3 -Trianisyl-methane (CH 3 O[4]C 6 H 4 ) 3 CH, m.p. 45-47, from anis- 
 aldehyde and anisol with glacial acetic-sulphuric acid (B. 35, 1197). 
 
 Leueo-rosolie acid (HO[4]C 6 H 4 ) 2 .CH.C 6 H 3 [4]OH[3]CH 3 , results from 
 the reduction of rosolic acid. Its triacetate melts at 148 (A. 179, 198). 
 
 III. A. PHENOL DERIVATIVES OF TRIPHENYL-CARBINOL. 
 
 These substances are formed by the oxidation of the oxy-triphenyl- 
 methanes or their ethers. They may also be produced by the direct 
 synthetic methods applicable to all triaryl-carbinols. 
 
 The p-hydroxylated triaryl-carbinols split off water more or less 
 easily, turning into methylene-quinones or diaryl-quino-methanes. 
 From p-oxy-triphenyl-carbinol we obtain, on heating, diphenyl-quino- 
 methane, which may be regarded as the root-substance of the dye- 
 stuffs of the triphenyl-methane series : 
 
 (C 6 H 5 ) 2 C(OH)C 6 H 4 [ 4 ]OH j=5.^ (C 6 H 5 ) 2 C : C 6 H 4 : O 
 
 p-Oxy-triphenyl-carbinol Diphenyl-quino-methane, fuchsone. 
 
 A. Triphenyl-carbinols hydroxylated in a Benzene Nucleus. o-Oxy- 
 triphenyl-carbinol, m.p. 140, from salicylic ester and phenyl-magnesium 
 bromide. It turns into phenyl-xanthone on distillation in a vacuum. 
 
PHENOL DERIVATIVES OF TRIPHENYL-CARBINOL 591 
 
 m-Oxy-triphenyl-earbinol, m.p. 148 (A. 354, 167). p-Oxy-triphenyl- 
 
 carbinol. Two modifications, melting at 139 and 165 respectively, 
 from p-oxy-triphenyl-acetic acid by expulsion of CO with H 2 SO 4 ; 
 also from the methyl ether, p-anisyl-diphenyl-carbinol, m.p. 84, the 
 condensation product of anisic acid ester with phenyl-magnesium- 
 bromide. p-Oxy-triphenyl-carbinol, and p-methoxy-triphenyl-carbinol 
 chloride, on heating to 200, expel H 2 O and CH 3 C1 respectively, forming 
 diphenyl-quino-methane, fuchsone, orange crystals, m.p. 168, which 
 easily takes up water and reverts into the carbinol. Oxy-dibromo- 
 triphenyl-carbinol ; diphenyl-dibromo-quino-methane, from diphenyl- 
 o-cresol-carbinol ; diphenyl-methyl-quino-methane (B. 36, 3558). 
 Diphenyl-quino-methanes are also produced by the condensation of 
 diphenyl-ketene with excess of quinones, by splitting off CO 2 from 
 the /Mactones first formed. 
 
 2, 5-Dioxy-triphenyl-carbinol, m.p. 136, from gentisinic ester and 
 C 6 H 5 MgBr. 2, 4-Dioxy-triphenyl-carbinol, m.p. 124, from benzo- 
 resorcin and C 6 H 5 MgBr. 3, 4-Dioxy-triphenyl-carbinol, by condensa- 
 tion of benzo-phenone chloride and pyro-catechin by means of con- 
 centrated H 2 SO 4 . On heating it expels water, and forms 3-oxy- 
 fuchsone, m.p. 123 (A. 372, 82). 
 
 B. Benzeins (see above) are produced by the condensation of 
 benzo-trichloride with mono- and polyhydric phenols, in which the 
 para-position with reference to a hydroxyl group is not substituted 
 e.g. o- and m-cresol, resorcinol, and pyro-catechin (but not p-cresol, 
 hydroquinone, etc.) (B. 23, R. 340). They are also formed when 
 their leuco-compounds, the corresponding oxy-triphenyl - methanes, 
 are oxidised. 
 
 The benzeins are generally red-coloured compounds with metallic 
 lustre. They dissolve on boiling with sodium bisulphite ; acids 
 precipitate them. Alkalies dissolve them with the formation of red 
 or violet-coloured salts. The carbon dioxide of the air decomposes 
 the latter. 
 
 p 2 -Dioxy-triphenyl-carbinol, phenol-benzein, benzaurin 
 
 r xi /-'/CgH^.OH /P W OTT 
 
 c li - c \CTH o or C 6 H 5 .C/ 6 4- is produced in the condensation of 
 
 | I ^VfH = O 
 
 benzo-trichloride and phenol (similar to the formation of malachite 
 green) (A. 217, 223), and by the oxidation of p-dioxy-triphenyl-methane, 
 into which it passes upon reduction. It is a brick-red, crystalline 
 powder. It breaks down, when fused with alkalies, into benzene and 
 dioxy-benzo-phenone, and this latter decomposes further into para-oxy- 
 benzoic acid and phenol. Its diacetate melts at 119. Dimethyl ether, 
 phenyl-p 2 -dianisyl-carbinol, m.p. 77, from phenyl-dianisyl-methane, 
 the condensation product of benzaldehyde and anisol, yields, on boiling 
 with dilute sulphuric acid, benzaurin (B. 36, 2791). 
 
 p 2 -Dioxy-m 2 -dimethyl-triphenyl-earbinol, o-cresol benze'in C 6 H 5 . 
 C(OH).[C 6 H 3 [3]CH 3 [4]OH] 2 , melts at 22O-225 (A. 257, 69). Further, 
 dioxy-triphenyl-carbinols have been obtained from the corresponding 
 dioxy-benzo-phenones with phenyl-magnesium bromide (A. 354, 177). 
 
 The oo '-dioxy-triphenyl-carbinols are only known in the form 
 of their anhydrides, the phenyl-xanthydrols C 6 H 5 .C(OH)^^*^O. 
 Special interest attaches to the phenyl-xanthydrols, hydroxylated or 
 
592 ORGANIC CHEMISTRY 
 
 amidated in the p-position, with regard to the central carbon atom, 
 which split off water spontaneously and pass into the quinoid . Phenyl- 
 
 /[i]C,H 4 [6] \ Q 
 fluorones C 6 H 6 .C^ f[6]/ and phenyl-fluorimes C 6 H 5 .C/^ 6jrL4 )O 
 
 the root-substances of the fluorescei'n and rhodamin dyes. The solu- 
 tions of these compounds in alkalies or acids show a strong fluorescence. 
 
 /C H \ 
 
 Phenyl-fluorone C 6 H 5 .C/ 6 4 >o chrome-red needles, m.p. 207 
 
 ^C 6 ri 3 O 
 
 is formed from the 4-amido-phenyl-fluorone by eliminating the amido- 
 group, and by condensation of 4-methoxy-xanthone with C 6 H 5 MgBr 
 and saponification of the methoxyl group with A1C1 3 . It is insoluble in 
 alkalies, but soluble in acids. By alcoholic potash the solution is made 
 colourless, and the carbinol is formed (A. 372, 293). 3- and 5-Oxy- 
 phenyl-xanthydrol, m.p. 170 and 162 respectively, are similarly 
 formed from 3- and 5-methoxy-xanthone. 
 
 Resorcin-benzein, ^-oxy-phenyl-fluorone C g H^.C/S f ^J!J No, is 
 
 \^C 6 H 3 ( : O) / 
 
 formed when water acts upon the reaction product of resorcinol and 
 benzo-trichloride (A. 217, 234), and when ZnCl 2 acts upon benzoic acid 
 and resorcin (/. pr. Ch. 2, 48, 387). Also from 4-amido-phenyl- 
 fluorone by way of the diazo-compound (A. 372, 294). Dinitro- 
 resorcin-benzein, see B. 26, 2064. 
 
 vic-Resorein-benzein, 2, z'-dio xy-phenyl-xanthydrol 
 C,u,.C(OH)<(^^^\o, from ^ 2 '_ d i oxy _ xanthone and G 6 H 5 MgBr 
 
 (A. 372, 132)." 
 
 Hydroquinone-benzein, 3, ^'-dioxy-phenyl-xanthydrol, is obtained 
 from 3, 3'-dimethoxy-xanthone and phenyl-magnesium bromide with 
 subsequent saponification (A. 372, 141), or by the condensation of 
 benzaldehyde and hydroquinone by means of concentrated H 2 SO 4 and 
 oxidation of the resulting xanthene derivative with FeCl 3 (A. 372, 301). 
 
 Oxy-hydroquinone-benzein, phenyl-trio xy -fluorone 
 
 C H C ^C 8 H*(OH)' -O^ ' by condensation of benzaldehyde and oxy- 
 hydroquinone with sulphuric acid (B. 37, 1171). 
 
 C. Amido - oxy - triphenyl - carbinols. 4 - Amido - phenyl - fluorone 
 C 6 H 5 .C/^H 3 (NH 2 )\ ^ m 0) d red need i eS) obtained in the form 
 
 M -'6 Jrl 3( : '-V / 
 
 of its acetyl compound by condensation of N-acetyl-m-amido-phenol 
 with benzo-trichloride besides 4, 4'-diacetamido-phenyl-xanthydrol, m.p. 
 248 (A. 372, 322). 
 
 Rosamines. These are the alkyl compounds of 4-amido-phenyl- 
 fluorime. They are formed when monoalkylic and dialkylic o-amido- 
 phenols act upon benzo-trichloride. While the benzei'ns from phenols 
 are very feeble dyes, whose alkali salts are even decomposed by carbon 
 dioxide, the hydrochlorides of the rosamines are red and violet dyes, 
 having great similarity to the rhodamines, possessing a blue tint and 
 a redder fluorescence (B. 22, 3001). They also result on heating re- 
 sorcinol benzem with dimethyl- and diethyl-aniline. 
 
 The simplest, rosamine, 4-amido-phenyl-fluorime 
 
 is obtained in the form of its chlorohydrate 
 
PHENOL DERIVATIVES OF TRIPHENYL-CARBINOL 593 
 
 in red needles, from the 4, 4'- diacetamido - phenyl - xanthydrol by 
 boiling with HC1 (A. 372, 316). 
 
 /QH /[4]N(CH 3 ) 2 
 
 Rosamine chloride C 6 H ft c/ ^No may be obtained from 
 
 [ 4 ]=N(CH 3 ) 2 C1 
 
 benzo-trichloride and dimethyl-amido-phenol. Red and blue mordant 
 dyes are obtained by the condensation of proto-catechu-aldehyde with 
 dialkyl-m-amido-phenols and with diakyl-anilines : proto-red (leuco- 
 compound) (HO) 2 C 6 H 3 CH[C 6 H 3 (OH)N(CH 3 ) 2 ] 2 and proto-blue (leuco- 
 compound) (HO 2 )C 6 H 3 CH[C 6 H 4 N(CH 3 ) 2 ] 2 ) (B. 36, 2913). 
 
 D. Aurins and Rosolic Acids. These compounds correspond 
 perfectly to the rosanilins. The free p 3 -trioxy-triphenyl-carbinols are 
 not known. When freed from their salts they sustain an intramolecular 
 anhydride formation. 
 
 These carbinol anhydrides are yellow in colour ; their alkali salts 
 dissolve in water, with a red colour. They are incompletely fixed by 
 the fibre of the material, and are only applied in the form of lakes in 
 the paper industry. 
 
 Aurin, para-rosolie acid, yellow corallin , 
 
 1UI 4JU 6 rl 4 / \ - / 
 
 is produced (i) on boiling the diazo-hydrochloride of para-rosanilin 
 with water (A. 194, 301) ; (2) by the condensation of p-dioxy-benzo- 
 phenone-chloride with phenol (B. 11, 1350) ; (3) by the condensation 
 of phenol with formic acid on heating with zinc chloride (/. pr. Ch., 
 2, 23, 549) ; and (4) by heating phenol (i part) with oxalic acid (f part) 
 and sulphuric acid (J part) to I3o-i5o (A. 202, 185). For the 
 by-products arising when aurin is prepared by method 4, and for 
 its separation from the same, see A. 194, 123 ; 196, 77 ; B. 28, 
 
 R. 743- 
 
 Aurin dissolves in glacial acetic acid and alcohol with a yellowish- 
 red colour, crystallises in dark-red needles or prisms with metallic 
 lustre, and decomposes when heated above 220. It dissolves in 
 alkalies with a fuchsine-red colour. With the primary alkaline 
 sulphites it readily yields colourless, crystalline derivatives, decom- 
 posable by acids and alkalies. Aurin forms crystalline compounds 
 with hydrochloric acid. Water decomposes them. Digested with 
 zinc dust and hydrochloric acid or acetic acid, aurin is reduced to 
 leucaurin or p 3 -trioxy-triphenyl-methane. Heated to 250 with water, 
 it breaks up into p 2 -dioxy-benzo-phenone and phenol. 
 
 Aurin is changed to para-rosanilin when it is heated with aqueous 
 ammonia to 150. An intermediate product (having i or 2 amide 
 groups) is the so-called peonine (red corallin). With aniline we obtain 
 triphenyl-para-rosanilin, and the intermediate product is azulin. 
 Consult B. 29, R. 510, for isomeric acetyl-aurins. Dimethyl-aurin, m.p. 
 i83-i86, is easily formed by methylation of aurin with diazo-methane 
 in ether suspension (M. 29, 653). 
 
 p 3 -Trianisyl-earbinol (CH 3 O[4]C 6 H 4 ) 3 COH, m.p. 84, colourless 
 crystals, from p 3 -trianisyl-methane with PbO 2 ; its OH group is more 
 capable of reaction than that of triphenyl-carbinol. It even transposes 
 to trianisyl-aceto-nitrile with prussic acid. o 3 -, m 3 -, and Ogp-Trianisyl 
 carbinols, m.p. 181, 119, and 110 respectively, have been prepared 
 VOL. II. 2 Q 
 
594 ORGANIC CHEMISTRY 
 
 from the magnesium compounds of o- and m-iodanisol with o-, m-, 
 and p-methoxy-benzoic ester (B. 35, 3024). 
 
 Rosolic acid C 20 H 16 O 3 is the inner anhydride of p s -trioxy-diphenyl- 
 m-tolyl-carbinoL Rosolic acid, like aurin, is obtained by boiling the 
 diazo-chloride of rosanilin with water (A. 179, 192) and by oxidising 
 a mixture of phenol and cresol C 6 H 4 (CH 3 )OH with arsenic acid and 
 sulphuric acid, whereby the linking menthane carbon is furnished by 
 the methyl group. When rosolic acid is digested with alcohol and 
 zinc dust, it is reduced to leuco-rosolic acid, from which it is obtained 
 by oxidation (B. 26, 254). 
 
 Trioxy-aurin C 1? H 14 O 6 results from the interaction of ZnCl 2 , pyro- 
 catechin, and formic acid (B. 26, 255). Resaurin C 19 H 14 O 6 is similarly 
 prepared with resorcin (/. pr. Ch. 2, 23, 547). Orcin-aurin C 22 H 1 O 5 
 (J. pr. Ch. 2, 25, 277 ; B. 13, 546). o-Amino-aurin, see B. 40, 3588. 
 
 Eupittonic acid, eupitton, hexamethoxy-aurin C^H^OCIrygOg, is 
 produced by oxidising a mixture of the dimethyl ester of pyrogallic 
 acid and methyl-pyrogallic acid. It is, therefore, an aurin in which 
 six methoxyl groups are present. It forms orange-yellow crystals, 
 melting with decomposition at 200. It dissolves with a deep blue 
 colour in alkalies, yielding salts which are precipitated by excess of 
 alkali (B. 12, 2216). Reich enbach (1835) observed the formation of a 
 blue-coloured barium salt when fractions of beechwood-tar were 
 allowed to stand with baryta water, and named it pittical (from TUT, 
 tar, and xaAW, beauty). When heated with ammonia, eupittonic acid, 
 just like aurin, affords an hexamethoxyl-rosanilin. Tetra- and hexa- 
 methoxy-triphenyl-carbinol, see B. 41, 4423. 
 
 Alcohols and Aldehydes of Triphenyl-methane. Few of them 
 are known : phenol-phthalol (HOC 6 H 4 ) 2 CHC 6 H 4 [2]CH 2 OH, melting at 
 190, was prepared by the action of sodium amalgam upon phenol- 
 phthalem (A. 202, 87). 
 
 p-Diphenyl-methyl-benzaldehyde (C 6 H 5 ) 2 CH[4]C 6 H 4 .CHO, boiling at 
 I9O-I95 (46 mm.), results from the condensation of tereph thai- 
 aldehyde and benzene with concentrated sulphuric acid (B. 19, 2029). 
 Dialdehydes have been prepared by the condensation of benzaldehyde, 
 m- and p-nitro-benzaldehyde with vanillin by means of ZnCl 2 . 
 
 Benzal-divanUlin C 6 H 5 CH[C 6 H 2 (OH)(OCH 3 )CHO] 2 , m.p. 222; m- 
 and p-nitro-benzal-divanillin, m.p. 266 and 276 with decomposition 
 (B. 36, 3975). 
 
 Carboxyl Derivatives of Triphenyl-methane. Triphenyl-methane- 
 carboxylic acids are produced (i) by reduction of triphenyl-carbinol- 
 carboxylic acids ; and (2) from their nitriles. The latter are prepared 
 by the action of aluminium chloride upon the cyano-benzal chlorides 
 and benzene. 
 
 Triphenyl-methane-o-carboxylic acid, benzol phthalin (see Phtha- 
 lems), (C6H 5 ) 2 CH.C 6 H 4 [2]CO 2 H, m.p. 162, is isomeric with triphenyl- 
 acetic acid, and is produced by the reduction of diphenyl-phthalide 
 (2), the lactone of triphenyl-carbinol-o-carboxylic acid (A. 202, 52), and 
 its nitrile. Chromic acid oxidises it to diphenyl-phthalide, while it 
 breaks down into carbon dioxide and triphenyl-methane when it is 
 heated with barium hydroxide. Sulphuric acid rearranges it to phenyl- 
 
 anthranol CJOH5* > CQ. 
 
CARBOXYL DERIVATIVES OF TRIPHENYL-CARBINOL 595 
 
 o-Cyano-triphenyl-methane (C 6 H 5 ) 2 CH.C 6 H 4 [2]CN melts at 89 
 and boils at 27O-285 (70-85 mm.). Preparation, see above (B. 24, 
 2572). 
 
 P 2 - Tetramethyl - diamido - triphenyl - methane - o - carboxylic acid 
 [(CH 3 ) gNMCeHJ 2 .CH.C 6 H 4 [2]CO 2 H, from tetramethyl-diamido-di- 
 phenyl-phthalide (A. 206, 101), melts at 200. 
 
 Triphenyl-methane-p-carboxylie acid melts at 161, and its nitrite 
 at 91 (B. 26, 3079). Methyl-triphenyl-methane-earboxylie acids, see 
 B. 16, 2364 ; 19, 3064 ; A. 234, 242. 
 
 Oxy-triphenyl-methane-carboxylic acids are formed in the reduction 
 of the oxy-triphenyl-carbinol-carboxylic acids. p-Oxy-triphenyl- 
 
 methane - o - carboxylic acid HO[4 ^ 6 **^>CH.C 6 H 4 [2]CO 2 H, melting at 
 
 (--6*15' 
 
 210 (B. 13, 1616), and p 2 -dioxy-triphenyl-methane-o-earboxylie acid, 
 phthalin [HOMC^HJaCH.C^^CO^H, melting at 225 (A. 202, 36, 
 I 53), were obtained from the corresponding oxy-triphenyl-carbinol-o- 
 carboxylic acids. Concentrated sulphuric acid converts them into the 
 corresponding oxy-phenyl-anthranols. 
 
 Hydrofluoranic acid C 6 H 4 | ^ CH \c!H![2]J ' melting at 226-228, 
 
 V[2]C0 2 H 
 
 results from the reduction of fluorane and tribromo-fluorane. When 
 the acid is distilled over lime, xanthone and benzene result, while di- 
 phenylene-phenyl-methane (B. 25, 3586) is produced in its distilla- 
 tion over baryta or soda-lime. 
 
 Fluoreseine, p 2 -dioxy-hydrofluorane-earboxylie acid, is the reduction 
 product of fluorescei'n. 
 
 p 2 -Dioxy-triphenyl-methane-m 2 -dicarboxylic acid is formed by con- 
 densation of benzaldehyde with salicylic acid by means of gaseous 
 HC1 (C. 1909, I. 747). 
 
 Carboxyl Derivatives of Triphenyl-carbinol, Phthalides. The 
 o-carboxyl derivatives of this class are especially noteworthy. They 
 cannot exist free ; they lose water and form lactones, which can be 
 regarded as diphenylated phthalides. 
 
 Diphenyl - phthalide, tripkenyl-carbinol-o-carboxylic acid lactone 
 
 r[i]C = (C 6 H 5 ) 2 
 C 6 H 4 j \ , melting at 115, is formed (i) by the oxidation of 
 
 triphenyl-methane-o-carboxylic acid, (2) in slight amount by the action 
 of mercury diphenyl upon phthalyl chloride, (3) from phthalyl chloride 
 and benzene with aluminium chloride. The third method of formation 
 serves for the preparation of diphenyl-phthalide, formerly considered 
 to be o-phthalo-phenone, until it was discovered to contain a lactone, 
 the basis of the phthaleins. 
 
 In the third method of producing diphenyl-phthalide the phthalyl 
 chloride may be replaced by phthalic anhydride. In this case o-benzoyl- 
 benzoic acid will be the first product, which by the further action of 
 benzene and aluminium chloride changes to diphenyl-phthalide. The 
 acetyl derivative of o-benzoyl-benzoic acid is better adapted for the 
 formation of diphenyl-phthalide than the free acid (B. 14, 1865). 
 
 Diphenyl-phthalide, when boiled with alkalies, forms salts of tri- 
 phenyl-carbinol-o-carboxylic acid, from the solution of which acids 
 re-precipitate diphenyl-phthalide. Zinc dust in alkaline solution 
 
596 ORGANIC CHEMISTRY 
 
 reduces triphenyl-carbinol-o-carboxylic acid to triphenyl-methane-o- 
 carboxylic acid. 
 
 The anilide C 6 H 4 | [1 (CeH5)2 , m.p. 189, and the hydrazide 
 
 [ [2]CO.NH.C 6 H 5 
 
 C 6 H 4 J * , m.p. 230, are produced on boiling diphenyl- 
 
 ([2]CON 2 HC 6 H 5 
 
 phthalide and aniline hydrochloride (B. 27, 2793) with phenyl-hydrazin 
 (B. 26, 1273). 
 
 Dithio-diphenyl-phthalide C 6 H 4 J \ 6 6 \ from diphenyl-phtha- 
 
 ([2]CSS 
 lide with sulphuretted phosphorus, see C. 1900, II. 575- 
 
 The nitration of diphenyl-phthalide produces two dinitro-diphenyl- 
 phthalides, from which two diamido-diphenyl-phthalides have been ob- 
 
 tained (A. 202, 66). 
 
 r[i]C = [C 6 H 4 [ 4 ]N(CH 3 ) 2 ] 2 
 p 2 -Tetramethyl-diamido-diphenyl-phthalidec 6 HJ \ 
 
 l[2]COO 
 
 m.p. 190, is obtained in the condensation of phthalic anhydride and 
 dimethyl-aniline with ZnCl 2 . If phthalic anhydride be substituted 
 for phthalyl chloride in this reaction there is an isomeric body, phthalyl 
 green, produced. This is probably an anthracene derivative, which is 
 also related to malachite green, and owes its origin to an admixture of 
 the phthalyl chloride to the phthalylene tetrachloride (C. 1898, 1. 330 ; 
 1903, 1. 85) . The esters of the colourless tetramethyl-diamido-diphenyl- 
 phthalide form intensely blue quinoid dyeing salts with acids. 
 
 Triphenyl-carbinol-m-carboxylie acid, m.p. 161, and triphenyl- 
 carbinol-p-earboxylie acid, m.p. 200, are formed when diphenyl-m- 
 tolyl-methane and diphenyl-p-tolyl-methane are oxidised with chromic 
 acid in glacial acetic acid solution. The latter also appears in the 
 oxidation of p-diphenyl-methyl-benzaldehyde, and of triphenyl- 
 methane-p-carboxylic acid (B. 16, 2369 ; 26, 3081 ; 37, 657). 
 
 Phenyl-p-tolyl-phthalide is made from acetyl-o-benzoyl-benzoic acid, 
 toluol, benzoyl-o-benzoic acid chloride and toluol, toluic-o-benzoic acid 
 chloride, and benzene with aluminium chloride (B. 14, 1867 ; 29, R. 
 995). Isomeric methylated diphenyl-phthalides are produced in the oxi- 
 dation of diphenyl-m- and p-xylyl-methanes. Ditolyl-phthalide melts 
 at 116 (C. 1898, 1. 209 ; A. 299, 286). See B. 28, 513, for di-biphenyl- 
 ([ilCO.O 
 
 o-phthalide c 6 H J 
 
 t[2]C=(C 6 H 4 .C 6 H 5 ) 2 
 
 Carboxyl Derivatives of the Oxy-triphenyl-carbinols. The phthaleins, 
 the derivatives of phthalide containing two phenol residues, are parti- 
 cularly important, and are dyes which are of great technical value. 
 A. v. Baeyer discovered them in 1871. The transition from them to 
 diphenyl-phthalide is found in 
 
 ,C 6 H 4 OH 
 
 Benzol-phenol-phthalide ^ H cob ' m>p ' l67 ' !t is 
 
 prepared from o-benzoyl-benzoic acid, phenol, and sulphuric acid 
 (A. 354, 171). Similarly we obtain : Resorcyl-phenyl-phthalide, m.p. 
 I 09i pyro-cateehm-phenyl-phthalide,m.p. 161; hydroquinone-phenyl- 
 phthalide, m.p. 247 ; pyrogallol-phenyl-phthalide, m.p. 189 (A. 372, 
 
DERIVATIVES OF OXY-TRIFHENYL-CARBINOLS 597 
 
 91). Of the polyoxy-diphenyl-phthalides mentioned, the p-substituted 
 ones dissolve in alkalies with a red colour, splitting the lactone ring and 
 forming p-quinoid salts (cp. Phenol-phthaleins). 
 
 The phthaleins result from the condensation of phthalic anhydride 
 (i mol.) with phenols (2 mols.) on heating with sulphuric acid, or, better, 
 with SnCl 2 to 120 (or with oxalic acid at 115). 
 
 The phthaleins derived from di- and polyhydric phenols are all 
 anhydrides, formed by the elimination of water from two phenol- 
 hydroxyls (A. 212, 347), in union with different benzene nuclei. In 
 the condensation of phthalic anhydride and phenol-p 2 -dioxy-diphenyl, 
 phthalide, or phenol-phthalein, is not the only product ; fluorane, the 
 anhydride of o. 2 -dioxy-diphenyl-phthalide, is also formed. It is the 
 simplest representative of the phthale'in anhydrides, which contain 
 a ring similar to the xanthone ring. 
 
 The free phthaleins are generally colourless, crystalline bodies. 
 They dissolve in the alkalies with intense colorations, and are again 
 separated from their solutions by acids (even CO 2 ). The addition of 
 concentrated caustic alkali causes the colours to disappear. On dilut- 
 ing with water, the colours reappear. 
 
 To show the similarity of the phthaleins to the aurins or rosanilins 
 in the formula, it is assumed that the free, colourless phthaleins con- 
 tain the lactone ring ; in their coloured alkali salt solutions this ring 
 is absent, and the methane carbon atom and an oxygen atom form a 
 quinone-like union with a benzene nucleus. This idea is apparently 
 supported by the preparation of phthalein-oxime : 
 
 C 6 H 4 .OH X C 6 H 4 OH /C 6 H 4 OH 
 
 f 
 \ 
 
 [21COO 64 \ [2]C0 2 H 1 [2]C0 2 H 
 
 Free phenol-phthalein Phenol-phthalein in coloured alkali salts. 
 
 This view is supported by the fact that the mm'-dioxy-ditoryl- 
 phthalide, which, on account of the non-existence of m-quinones, cannot 
 be analogously formulated, is dissolved quite colourlessly in alkalies. 
 Much excess of alkali decolourises the solutions of phenol-phthalein 
 with formation of salts of the carbinol NaO 2 CC 6 H 4 .C(OH)(C 6 H 4 ONa) 2 
 (C. 1904, I. 1088). 
 
 It should be added that lactone esters and ethers have": 'also 
 been obtained by acidulation and alkylisation of phenol-phthalein in 
 alkaline solution (B. 28, 3258 ; 29, 131 ; cp. B. 29, R. 552). 
 
 The phenol-phthaleins, by reduction, yield oxy-triphenyl-methane- 
 carboxylic acids the phthalins. The latter are changed by concen- 
 trated sulphuric acid into oxy-phenyl-anthrone derivatives, called 
 phthalidins. The oxidation of the latter produces the phthalidelns, or 
 oxy-phenyl-oxanthrone derivatives. The following diagram represents 
 these changes, with phenol-phthalein as the example : 
 
 ( 
 
 6 H 4 \C-H-OH CeH _ CA C.H.OH -_ c.H 4 .H,OH 
 
 Iwcoo + IMCOOH ~ H ' + ^ co ~ ^ 
 
 \Jn. 
 
 Phthalein, Phthalin, Phthalidin, Phthalidein 
 
 p z -dioxy-diphenyl- p 2 -dioxy-triphenyl- dioxy-phenyl- dioxy-phenyl- 
 
 phthalide methane-o-carboxylic acid anthrone oxanthrone 
 
598 ORGANIC CHEMISTRY 
 
 Phenol-phthalein, p 2 -phthalein, dioxy-diphenyl-phthalide C 20 H 14 O 4 . 
 is a yellow powder, crystallising from alcohol in colourless crusts, and 
 melting at 250. It dissolves in the alkalies with a red colour. It is 
 used as an indicator in alkalimetry, especially in determining carbon 
 dioxide with baryta (B. 17, 1907). It is formed from phthalo-phenone 
 when nitrous acid acts on the p-diamido-compound ; by oxidising an 
 alkaline solution of the corresponding phthalin with air, or with potassium 
 f erricyanide or potassium permanganate, and is also obtained on heating 
 phthalic anhydride with phenol and tin chloride, or with sulphuric acid 
 to II5-I2O for eight hours. o 2 -Dioxy-diphenyl-phthalide anhydride, 
 insoluble in caustic potash, is a by-product, sometimes also fluorane 
 (A. 202, 68). Boiling caustic potash and zinc dust reduce phthalein 
 to phthalin, and it is decomposed into p 2 -dioxy-benzo-phenone and 
 benzoic acid by fusion with caustic potash. 
 
 Derivatives of Phenol-phthalein. Diaceto-phenol-phthalem melts at 
 143. Dibenzoyl-phenol-phthalein melts at 169 (B. 29, 131). 
 
 Phenol-phthalein methyl ester CH 3 ococ 6 H 4 .c<f^ 4 ' m.p. 
 
 \C 6 rl 4 .(Jrl 
 
 I27-I3O, orange needles, is formed by esterification of phenol-phtha- 
 lein with methyl-alcoholic H 2 SO 4 ; it dissolves in alkalies with a violet 
 colour, and is easily re-saponified to phenol-phthalein (B. 40, 3484, 
 3726). The lactoid phenol-phthalein mono- and dimethyl ethers, m.p. 
 149 and 100, are obtained by alkylation of phenol-phthalein in alka- 
 line solution (B. 40, 3729). The latter has also been obtained syn- 
 thetically from phthalic anhydride, anisol, and A1C1 3 (B. 29, R. 550). 
 
 f[i]C=(C 6 H 4 .OH) 2 
 Phenol-phthalem-anilide C 6 H 4 { \ , m.p. 270 (B. 26, 3077) . 
 
 { [2]CONC 6 H 5 
 
 Phenol-phthalem-oxime (C 29 H 14 O 3 ) : NOH (?), a yellow crystalline 
 powder, melting with decomposition at 221, and produced by the action 
 of hydroxylamine upon an alkaline phenol-phthalein solution. With 
 dimethyl sulphate in alkaline solution it gives a dimethyl ether. This 
 indicates a formula of the lactame type C 6 H 4 {^ H *' OH)2 ^NOH. 
 
 Boiling dilute sulphuric acid decomposes the oxime into p-oxy-o-ben- 
 zoyl-benzoic acid and p-amido-phenol (B. 42, 2825). Tetraehloro- 
 phenol-phthalem C 20 H 10 C1 4 O 4 , m.p. above 300 (C. 1909, II. 127). 
 Tetrabromo-phenol-phthalem, m.p. 220-230 with decomposition. 
 Tetra-iodo-phenol-phthalein is used commercially as an iodoform sub- 
 stitute under the name " nosophene." 
 
 Tetrabromo-phenol-phthalein-oxime (B. 26, 2260; C. 1900, 1. 1291). 
 Quinoid tetrabromo-phenol-phthalein-mono- and -diethyl ether, see B. 
 40, 1437- 
 
 m, m-Dioxy-p-ditolyl-phthalide, m.p. 206, see A. 354, 185. 
 
 Fluorane, o 2 -phenol - phthalein anhydride 4 
 
 melting at I73-I75, is produced, together with p 2 -phenol-phthalein, 
 by the condensation of phthalic anhydride and phenol. Fluorane 
 yields hydro-fluoranic acid by reduction, and diphenylene-phenyl- 
 methane when it is distilled over zinc dust (B. 25, 3586). The anile 
 
 C 6 H 4 { ] ' \ * melts at 242 (B. 27, 2793). Tribromo-fluorane 
 I [2]CON.C fl H 6 
 
DERIVATIVES OF PHENOL- PHTHALEIN 599 
 
 C2oH 19 .Br3O 3 , m.p. 298-300, is produced by the action of PBr 5 
 upon fluorescein, and is reduced by alcoholic caustic soda and 
 zinc dust to hydro-fluoranic acid (B. 25, 1388). Concerning nitro- 
 fluoranes, see B. 31, 1739 ; 32, 1131, 2108. 3, 6-Dimethyl-fluorane, 
 m.p. 213, see C. 1910, I. 449. 
 
 The fluoresceins are the o-phthalic anhydrides produced by the 
 condensation of phthalic anhydrides with resorcin. They are char- 
 acterised by a beautiful fluorescence ; this is especially true of their 
 alkaline solutions (Baeyer, A. 183, i). 
 
 Phthalic anhydride may also be replaced by the anhydrides of 
 aliphatic dicarboxylic acids. When succinic, maleic, and citraconic 
 anhydrides are condensed with resorcin, the corresponding fluoresceins 
 are produced. Pyro-mellithic and mellithic acids, and their anhydrides, 
 also combine with resorcin to form dyestuffs resembling fluoresceln, 
 and these contain i, 2, or 3-fold xanthyl groups (C. 1907, I. 549). 
 
 See also o-sulpho-benzoic acid and naphthalic acid (B. 15, 883 ; 
 18,2864; 24, R. 763; 26, R. 542; 29,2824). Hydroquinone-sueeinein, 
 C. 1908, II. 786 ; pyrogallol-succinein, C. 1899, II. 758. 
 
 Resorcin-phthalem, fluorescem C 20 H 12 O 5 , is prepared by heating 
 phthalic anhydride (2 parts) with resorcin (7 parts) to 200, or with 
 anhydrous oxalic acid (B. 17, 1079) to iio-ii7. When precipitated 
 from its salts it occurs in yellowish-red flakes C 20 H 14 O 6 , which quickly 
 lose water, and become C2oH 12 O 5 , which dissolves in alcohol with a 
 yellow-red colour and green fluorescence, and dries out as a red powder. 
 Upon reduction fluorescem yields fluorescin, and PC1 5 converts it into 
 fluoresceln chloride, p z -dichloro-fluorane (see Rhodamines). On treat- 
 ment with alcoholic KSH this yields thio - fluorescem C 8 H 4 O 2 : 
 (C 6 H 3 .SH) 2 :0(B. 32,1127). 
 
 r[i]C=(C 6 H 3 OH) 2 
 Baeyer ascribed the formula C,H 4 -^ to fluorescein. 
 
 I [2]COO 
 
 As there was a disposition to assume that the phthalic acid 
 residue replaced both m-hydrogen atoms (5) in the resorcin mole- 
 cules, R. Meyer showed that fluorescein is a dioxy-derivative of o- 
 phenol-phthalein anhydride, for which reason he gave it the name 
 fluorane (above) ; and that, therefore, the phthalic acid residue oc- 
 cupied the o-position with reference, at least, to each of the hydroxyl 
 group of the resorcin molecule, and between these hydroxyl groups the 
 anhydride formation occurred. R. Meyer converted fluorescein (i) 
 by means of PBr 5 into tribromo-fluorane (2), which, like fluorane (4) 
 itself, yields hydro-fluoranic acid (3) upon reduction. Fluorescein and 
 fluorane contain a ring, closely related to the xanthone ring ; indeed, 
 hydro-fluoranic acid may be decomposed into xanthone and benzene : 
 
 ( x ) rwo^W^^Xo (*) (3) f[i]CH<' c H N > (4) r[i] 
 
 C,H 4 > <\C.H.(OH)[6] j > C.oH.Br.O, - > C.H J \C.H 4 / < - C.HJ ' 
 
 l[ 2 ]COO IWCOOB \ [2] COO 
 
 The intense colour of fluorescein led Bernthsen and others to 
 ascribe a quinoid constitution to free fluorescein and its coloured 
 derivatives (see Phenol - phthalem) . The assumption of a free 
 carboxyl group in fluorescein is supported by its solubility in sodium 
 bicarbonate, and its esterification with alcohol and sulphuric acid 
 (see below). 
 
600 ORGANIC CHEMISTRY 
 
 The colourless derivatives were supposed to have their origin in 
 the lactone formula of fluorescein. This view allies fluorescein and its 
 coloured derivatives with the aurins and rosanilins. 
 
 When fluorescein is fused with caustic soda it breaks down into 
 resorcinol and monoresorcinol-phthalein, or dioxy-benzoyl-benzoic 
 acid. Bromine in glacial acetic acid changes the latter to dibromo- 
 dioxy-benzoyl-benzoic acid, which fuming sulphuric acid rearranges 
 to dibromo-xantho-purpurin ; it is also obtained from eosin. Hence 
 it follows that monoresorcinol-phthalein is 2, 4-dioxy-o-benzoyl-benzoic 
 acid, because if it were 2, 6-dioxy-o-benzoyl-benzoic acid it would be 
 impossible for an anthraquinone condensation to occur (Heller, B. 28, 
 314; B. 29,2623). 
 
 Derivatives of Fluorescein. Fluoreseein-anilide and fluoreseein- 
 
 C(C 12 H 8 3 ) C(C 12 H 3 3 ) 
 
 phenyl-hydrazide C 6 H 4 ^ and C 6 H 4 < , from fluor- 
 
 CONC 6 H 6 \CON 2 HC 6 H 6 
 
 escein on heating with aniline or phenyl-hydrazin, form colourless 
 crystals ; the anilide yields a dimethyl ether, m.p. 207 (B. 28, 396 ; 
 
 32,H33). _ 
 
 Fluorescein - carboxyl - methyl ester CH 3 oco[>]C 6 H 4 c/ 
 
 m.p. 252, iridescent green crystals, is formed by the esterification of 
 fluorescein with sulphuric acid and methyl alcohol (B. 34, 2641). 
 On further methylation with dimethyl sulphate in nitro-benzol 
 solution it yields the quinoid fluorescein - dimethyl - ether ester 
 
 /C 6 H 3 OCH 3 
 
 CH 3 OCOC 6 H 4 C/ >O , m.p. 177, brick-red needles (B. 28, 396), 
 C 6 H 3 =O 
 
 rc< C 6 H 3 (OCH 3 r 
 
 besides the colourless lactoid dimethyl ether C 6 H 4 J ^ C 6 ] 
 
 (coo 
 
 m.p. 198, probably produced by isomerisation (cp. B. 40, 3603). The 
 latter is also obtained from its anilide upon heating with concentrated 
 sulphuric acid. The latter, on esterification with methyl alcohol and 
 HC1, passes into the trimethyl ether of dioxy-xanthydrol-carboxylic 
 acid, which possesses strong basic properties and forms, with acids, 
 highly coloured salts soluble in water without hydrolysis (A. 371, 326), 
 corresponding to the coloured salts of triphenyl-carbinol (cp. A. 370, 
 142). 
 
 Substituted Fluoresceins. Although fluorescein itself is not applic- 
 able as a dye, by introducing halogens and nitro-groups into it dyestuffs 
 of remarkable beauty can be obtained. If we start with fluorescein, 
 then the substitution will occur in the resorcinol residues. 
 
 If bromine be allowed to act on fluorescein suspended in glacial 
 acetic acid, eosin, tetrabromo-fluorescein C 20 H 8 Br 4 O 5 is produced. 
 Crystallised from alcohol it forms red crystals. The potassium and 
 sodium salts constitute the eosin of commerce, soluble in water, and 
 imparting to wool and silk a beautiful rose-colour. In the case of the 
 sodium salt there is a yellowish -red fluorescence (Caro, 1873). 
 
 Erythrosin, tetra-iodo-fluor escein C 20 H 8 I 4 O 5 . 
 
 Saf rosine, eosin scarlet, dibromo-dinitro-fluoresceinfC 20 H 8 Br 2 (NO 2 ) 2 O 5 , 
 is formed when bromine acts upon dinitro-fluorescein, or when nitric 
 acid acts upon di- or tetra-bromo-fluorescein (A. 202, 68). See B. 30, 
 
SUBSTITUTED FLUORESCEINS 601 
 
 333, for the dinitro-fluorescein yellow from dinitro-fluorescei'n and 
 ammonia. 
 
 To obtain the fluorescei'ns substituted in the phthalic acid residue, 
 condense the chlorinated phthalic anhydrides with resorcinol (Noel ting) . 
 The bromo- and iodo-fhiorescei'ns, with the substituents in the re- 
 sorcinol residues, are at the same time prepared from the chlorinated 
 bodies : 
 
 Phloxin, tetrabromo-dichloro- and tetrabromo-tetrachloro-fluorescem 
 C 20 H 4 Cl 4 Br 4 O 5 , rose Bengal, tetra-iodo-tetrachloro-fluorescem. 
 
 Phthalic anhydride has also been condensed with pyro-catechol 
 (B. 40, 1442), hydroquinones, orcins, and phloro-glucin. 
 
 Hydroquinone-pnthalem, m.p. 226, is formed from hydroquinone 
 and phthalic anhydride, as well as from fluorane, by transforming into 
 2, 7-dinitro-fluorane, diamido-fluorane, and treating the latter with 
 nitrous acid (B. 28, 2959 ; 31, 1743). It shows no fluorescence, and it 
 also differs from fluoresce'in in colour ; it approaches phenol-phthalein 
 in its behaviour (B. 36, 2949). In alkalies, hydroquinone-phthalem 
 dissolves with a violet and somewhat unstable colour, o-quinoid salts 
 being produced with a probable splitting of the xanthone ring (cp. 
 hydroquinone-benzein, above, and A. 372, 133). For esters of hydro- 
 quinone-phthalem, see A. 372, 298. The condensation of phthalic 
 anhydride with orcin produces three orcin-phthaleins ; only that orcin- 
 phthalein which contains two hydroxyl groups in the p-position, i.e. 
 the phthalic residue, turns out to be a perfect analogue of fluorescem 
 (B. 29, 2630). 
 
 Pyrogallol-phthalein, gallein HOCO[ 2 ]C 6 H 4 c^^ ( ( ^2o (?) is 
 obtained on heating pyrogallic acid with phthalic anhydride to 200. 
 It forms crystals with green colour, dissolving with a dark-red colour in 
 alcohol and with a beautiful blue colour in excess of alkalies. 
 
 It is converted by concentrated sulphuric acid into ccerule'in (see 
 A. 209, 249). The latter is a permanent green anthracene dyestuff 
 (A. 209, 249 ; C. 1900, II. 100 ; 1901, II. 775). Tetrachloro-gallein, 
 see C. 1909, II. 2161. 
 
 Oxy-hydroquinone-phthalem, like the isomeric gallein, and in con- 
 trast with phloro-glucin-phthalein, which does not contain the hydroxyl 
 groups in the ortho-position, is an excellent mordant for cotton. Like 
 gallein, it is condensed by concentrated sulphuric acid to an anthracene 
 derivative violem ; oxy-hydroquinone reacts like resorcin with many 
 other i, 2-dicarboxylic anhydrides, with formation of phthaleiin (B. 34, 
 2617, 2637 ; 35, 1782 ; 36, 1070). 
 
 The rhodamins, the phthaleins of m-amido-phenol and its derivatives, 
 are of special importance. They are violet-red, magnificently fluores- 
 cent dyestuffs. In constitution they are perfectly analogous to the 
 fluoresceins. 
 
 The simplest rhodamin is formed when m-amido-phenol hydro- 
 chloride and phthalic anhydride are heated to 190 with concentrated 
 sulphuric acid (B. 21, R. 682). 
 
 The alkylic rhodamins possess more intense colours. They are 
 produced when rhodamin hydrochloride is heated with alkyl iodides. 
 A better course to pursue is the condensation of alkylic m-amido- 
 phenols and phenyl-m-amido-phenol with phthalic anhydride (B. 21, 
 
602 ORGANIC CHEMISTRY 
 
 R. 682, 920 ; 22, R. 788). Still another procedure consists in re- 
 arranging fluorescein chloride, melting at 252 (the product of the 
 action of PC1 5 upon fluorescein), by heating it with dialkylamines (B. 22, 
 R. 625, 789). 
 
 Anisolines, alkyl ethers of the rhodamins (?) see B. 25, R. 866. 
 
 Suecino-rhodamin has been obtained from succinic anhydride and 
 m-amido-phenol (B. 23, R. 532). 
 
 Di-salieylie acid phthalide c 6 H 4 ( Cl ]a , m.p. 276 
 
 l[ 2 ]COO 
 
 with decomposition, is formed besides phthaloyl-salicylic acid from 
 phthalic anhydride, salicylic ester, and A1C1 3 (A. 303, 280). 
 
 III. B. p-Phenylene-bis-diphenyl-methane C 6 H/^ ( ^ 5 \ 2 , from the 
 
 \L,ti(i^ 6 t 5 ) 2 
 
 corresponding glycol by reduction with zinc and glacial acetic acid. 
 Derivatives of this hydrocarbon are obtained by the introduction of the 
 CH(C 6 H 5 ) 2 group into quinones and quinoid substances by means of 
 benzo-hydrols. 
 
 Benzo - quinone - bis - diphenyl - methane C 6 H 2 O 2 [CH(C 6 H 5 ) 2 ] 2 , m.p. 
 250. Benzo-quinone-bis-tetramethyl-diamido-diphenyl-methane, m.p. 
 245, from tetramethyl-diamido-benzo-hydrol and quinone on heating 
 in alcoholic solution (B. 32, 2146). 
 
 p - Phenylene - bis - diphenyl - earbinol, tetraphenyl-p-xylylene-glycol 
 (C 6 H 5 ) 2 C(OH)[i]C 6 H 4 [4]C(OH)(C 6 H 5 ) 2 , m.p. 169, is obtained from 
 terephthalic ester and C 6 H 5 MgBr. On boiling with silver, the benzene 
 solution of the bromide (C 6 H 5 ) 2 CBrC 6 H 4 CBr(C 6 H 5 ) 2 gives tetraphenyl- 
 dimethylene-quinone (C 6 H 5 ) 2 C : C 6 H 4 : C(C 6 H 5 ) 2 , orange needles, m.p. 
 239-242 ; the latter adds bromine with decoloration, eliminates 
 iodine from HI, and is related to the methylene-quinones (B. 37, 1463 ; 41, 
 2746). Tetraphenyl-methylene-quinones are also produced by the con- 
 densation of two molecules diphenyl-ketene with one molecule quinone, 
 with rejection of two molecules CO 2 from the unstable jS-dilactones 
 first formed. On treating the glycol with aniline salt or with phenol in 
 glacial acetic acid we obtain p 2 -diamido- and p-dioxy-hexaphenyl-p-xylol 
 H 2 NC 6 H 4 .C(C 6 H 5 ) 2 C 6 H 4 C(C 6 H 5 ) 2 C 6 H 4 NH 2 , m.p. 358, and HOC 6 H 4 C 
 (C 6 H 5 ) 2 C 6 H 4 C(C 6 H 5 ) 2 C 6 H 4 OH, m.p. 304 (B. 37, 2001). 
 
 III. C. Tetraphenyl-methane C(C 6 H5) 4 , m.p. 282, b.p. 431 with 
 sublimation, is formed from the diazonium sulphate of p-amino-tetra- 
 phenyl-methane by boiling with alcohol, and also, in small quantities, 
 by heating triphenyl-rmethane-azo-benzol to 100 (B. 36, 1090). Also 
 by transformation of triphenyl-chloro-methane with phenyl-magnesium 
 chloride (B. 39, 1463). 
 
 p-Amido- and p-oxy-tetraphenyl-methane NH 2 [4]C 6 H 4 C(C 6 H 5 ) 3 , 
 m.p. 245, and HO[4]C 6 H 4 C(C 6 H 5 ) 3 , m.p. 282, is easily obtained from 
 triphenyl-carbinol in glacial acetic acid by heating with aniline chloro- 
 hydrate and phenol respectively, and concentrated sulphuric acid 
 (B. 35, 3018 ; 36, 407 ; 37, 659 ; A. 363, 284). 
 
 p-Diphenyl-methyl-tetraphenyl-methane (C 6 H 5 ) 2 CH [4] C 6 H 4 C (C 6 H 5 ) 3 , 
 m.p. 231, is formed from triphenyl-carbinol, or its chloride, by re- 
 duction with zinc and stannous chloride, HC1, and glacial acetic acid ; 
 also from hexaphenyl-ethane and triphenyl-methyl by the action of 
 HC1 (B. 37, 4790). Also synthetically by way of p-benzoyl-triphenyl- 
 methane C 6 H 5 COC 6 H 4 CH(C 6 H 5 ) 2 , m.p. 166 (B, 41, 2421). 
 
HOMOLOGOUS DI- AND POLY-PHENYL-PARAFFINS 603 
 
 IV. HOMOLOGOUS Di- AND POLY-PHENYL-PARAFFINS. 
 
 Homologous series are derived from diphenyl-methane. Dis- 
 missing the substitutions in the benzene residues, this is attained by 
 replacing the H atoms of the methylene residue by alkyl groups : 
 diphenyl-methyl-, diphenyl-dimethyl-, diphenyl-ethyl-, diphenyl- 
 propyl-methane, etc., denoted as " gem-" (geminated) diphenyl-paraffins 
 (B. 31, 2068) ; and again, it can be done by inserting new C atoms 
 between the two benzene residues : w, cu-diphenyl-ethane or dibenzyl, 
 a}, oj-diphenyl-propane, cu, o;-diphenyl-butane, co, cu-diphenyl-pentane, 
 etc. The group of unsym. diphenyl-ethanes and the homologous gem- 
 diphenyl-paramns will receive first attention in the following para- 
 graphs. Its members attach themselves in their behaviour to di- 
 phenyl-methane and its derivatives ; at the same time they show in 
 many ways their genetic relationship to the dibenzyl group. Compare 
 benzilic acid, diphenyl-acetaldehyde, stilbene, tolane. 
 
 After these there will follow the important dibenzyl or sym. 
 diphenyl-ethane group, and then the cu, co-diphenyl, propane, butane, 
 pentane, and hexane groups. The derivatives alkylised or pheny- 
 lated in the benzene nuclei, or in the side chains connecting these, are 
 included with the parent hydrocarbons of the individual groups ; the 
 saturated are followed by the unsaturated hydrocarbons. 
 
 A. Gem-diphenyl-paraffins and their Derivatives are, as a rule, formed 
 
 (1) by the condensation of aldehydes, chlorinated aldehydes, glyoxylic 
 acid, etc., with benzene hydrocarbons, phenols, or tertiary anilines, 
 just as the diphenyl-methanes are produced by means of methylal, 
 methylene iodide, etc. : 
 
 CH 3 CHO+2C 6 H 6 - > CH 3 CH(C 8 H 5 ) 2 +H 2 0. 
 
 (2) Diphenyl-alkyl-carbinols are obtained by the condensation of 
 benzo-phenone with magnesium-alkyl iodides or from phenyl-mag- 
 nesium bromide with fatty-acid esters and chlorides (Grignard's 
 reaction) . The carbinols easily split off water and form gem-diphenyl- 
 olefms, which are reducible by Na and alcohol to gem-diphenyl-paramns : 
 
 (C 6 H 5 ) 2 CO CH,^ (C 6 H 5 ) 2 C(OH)CH 3 ^H.CO.R 2 C 6 H 5 MgBr 
 ( C 6 H 5 ) 2 C(OH).CH 2 CH 3 -- > (C 6 H 5 ) 2 C : CHCH 3 - -+ C 6 H 5 CH r CH 2 CH 3 . 
 
 All the substances included in this class yield benzo-phenone or its 
 derivatives when they are oxidised. 
 
 Unsym. diphenyl-ethane (C 6 H 5 ) 2 CHCH 3 , b.p. 209 (145 at 13 
 mm.), is made from benzene and paraldehyde with cold sulphuric 
 acid ; also from ethidene chloride CH 3 CHC1 2 , sym. bromethyl-benzol 
 CgHg.CHBr.CHg, or styrol with benzene and A1 2 C1 6 . Chromic acid 
 oxidises it to benzo-phenone, with the elimination of the methyl 
 group. Consult B. 27, 3238. Nitric acid nitrates the side chains 
 and the benzene residues of unsym. diphenyl-ethane. The products 
 are : diphenyl-ethylene-glycol mononitrate (C 6 H 5 ) 2 C(OH).CH 2 (ONO), 
 melting at 100, diphenyl-vinyl nitrite (C 6 H 5 ) 2 C=CH(ONO), melting at 
 86, and a dinitrite melting at I48-I49. The latter is probably a 
 diphenyl-ethylene derivative. These three compounds have great 
 crystallising power. They form yellow crystals, and when oxidised 
 yield benzo-phenone (A. 233, 330). 
 
604 ORGANIC CHEMISTRY 
 
 Unsym. phenol-phenyl-ethaneC 6 H 5 CH(CH 3 )C 6 H 4 .OH, melting at 58, 
 is produced when sulphuric acid acts upon phenol and styrol ; the 
 homologous phenols, naphthols, etc., behave similarly toward styrol 
 (B. 24, 3891). Unsym. diphenol-ethane (C 6 H 4 OH) 2 CHCH 3 , melting at 
 122, can be obtained from aldehyde and phenol (B. 19, 3009). 
 
 Unsym. p 2 -tetramethyl-diamido-diphenyl-ethane [(CH 3 ) 2 NC 6 H 4 ] 2 
 CHCH 3 , m.p. 69, is split up by nitrous acid with formation of p-nitro- 
 dimethyl-aniline (C. 1899, II. 203 ; 1900, I. 252). 
 
 gem-Diphenyl-propane, -butane, -hexane, b.p. 10 142, 150, 164, 
 from the corresponding olefins (see below) with Na and alcohol (C. 
 1902, II. 1209). 
 
 Diphenyl-methyl-, -ethyl-, -propyl-, -amyl-earbinol (C 6 H 5 ) 2 C(OH)R, 
 m.p. 81, m.p. 95, b.p. 15 185, m.p. 47, from benzo-phenone with 
 alkyl-magnesium iodides or phenyl-magnesium bromide and fatty 
 esters, by method 2 (see above). By distillation and dehydrating 
 processes we obtain from these carbinols : gem-diphenyl-ethylene, 
 -propylene, -butylene, -hexylene, b.p. 270, 280, m.p. 52, 292, 314 ; 
 unsym. diphenyl-ethylene is also formed from a-diphenyl-jS-chlor- 
 ethane (see below), and from unsym. dibromo-ethylene with benzene 
 and A1C1 3 . It easily splits off formaldehyde by auto-oxidation. Gem- 
 diphenyl-propylene with Br immediately gives a-diphenyl-j3-bromo- 
 propylene (C 6 H 5 ) 2 C : CBrCH 3 , m.p. 49 (B. 35, 2646 ; 37, 230, 1447 ; 
 C. 1901, I. 1337; 1902, II. 1209). o - Oxy - diphenyl - ethylene 
 HO[ 2 ]C 6 H 4 C(C 6 H 5 ) : CH 2 , b.p. 13 167, see B. 36, 4002. 
 
 Several halogen derivatives of mono-substituted diphenyl-ethylenes 
 
 p TT TT 
 
 of the general formula 6 5 \c : c< , occur in cis-trans-isomeric 
 
 Lx 6 .H. 4 X/ \-H-lg 
 
 forms which can be transformed into each other by means of ultra- 
 violet light (A. 342, i ; B. 42, 4865). 
 
 Unsym. diphenyl-monochloro-ethane (C 6 H 5 ) 2 CH.CH 2 C1 is an oil. 
 Diphenyl-dichloro-ethane(C 6 H 5 ) 2 CH.CHCl 2 ,melting at 8o,and diphenyl- 
 triehloro-ethane (C 6 H 5 ) 2 CH.CC1 3 , melting at 64, are obtained from mono-, 
 di-, and trichloro-acetaldehyde (chloral) with benzene and sulphuric acid. 
 Alkali, acting upon these substances, splits off hydrogen chloride, and 
 the products are : 
 
 Unsym. diphenyl-ethylene, diphenyl-monochloro-ethylene (C 6 H 5 ) 2 C : 
 CHC1, melting at 42 and boiling at 298, and diphenyl-dichloro-ethylene 
 (C 6 H 5 ) 2 C : CC1 2 , melting at 80 and boiling at 316, which is also found 
 in the condensation products of chloral with benzene and aluminium 
 chloride (B. 26, 1955)- If diphenyl-monochloro-ethane be heated alone 
 it splits off hydrochloric acid and is rearranged to stilbene. The 
 latter is similarly produced by the reduction and rearrangement of 
 diphenyl-trichloro-e thane with zinc dust and alcohol. When diphenyl- 
 monochloro-ethylene is heated with a sodium ethylate solution it is 
 transformed into tolane. Diphenyl - vinyl - ethyl ether (C 6 H 5 )C : 
 CHOC 2 H 5 is formed simultaneously : 
 
 (C 6 H 5 )CH.CH 2 C1 - -> C 6 H 5 .CH : CH.C 6 H 5 
 (C 6 H 5 ) 2 CH : CHC1- --> H 6 C 5 .C = C.C 6 H 5 . 
 
 These transposition reactions have been extended to a series of 
 substituted diphenyl-mono- and trichloro-ethanes and to diphenyl- 
 monochloro-ethylene (A. 279, 319 ; B. 26, R. 270). 
 
HOMOLOGOUS DI- AND POLY-PHENYL-PARAFFINS 605 
 
 Unsym. diphenyl-ethylene-glycol (C 6 H 5 ) 2 C(OH).CH 2 OH, m.p. 121, 
 is formed from glycolic ester or benzoyl-carbinol by transformation into 
 phenyl-magnesium bromide. Similarly we obtain diphenyl-propylene- 
 glycol (C 6 H 5 ) 2 C(OH).CH(OH).CH 3 , m.p. 96; 1, 1-diphenyl-glycerin 
 (C 6 H 5 ) 2 C(OH)CH(OH).CH 2 OH, m.p. 158; and diphenyl-ethylene- 
 chloro-hydrin (C 6 H 5 ) 2 C(OH).CH 2 C1, m.p. 66, from lactic ester, glyceric 
 ester, and chloracetic ester with C 6 H 5 MgBr respectively. The- latter, 
 on heating with sodium ethylate, gives diphenyl-ethylene oxide (C 6 H 5 ) 2 
 
 C.O.CH 2 , m.p. 56 (B. 39, 1753, 2288). 
 
 On heating with 20 per cent, sulphuric acid, diphenyl-ethylene 
 oxide, distilled in a vacuum, passes into diphenyl-aeetaldehyde (C 6 H 5 ) 2 
 CH.CHO, b.p. 166, oxime, m.p. 120, which is also formed by saponi- 
 fication with glacial acetic acid and hydrochloric acid instead of di- 
 phenyl-vinyl alcohol. 
 
 The aldehyde in many respects behaves analogously to the oxy- 
 methylene derivatives e.g. when it is oxidised it does not change to 
 the acid, but splits off the CHO group and becomes benzo-phenone 
 (B. 24, 1780 ; 25, 1781). Diphenyl-aeetaldehyde is also formed from 
 the hybro-benzoins by dehydrating agents. Anhydrides of the hydro- 
 benzoins are formed at the same time : 
 
 C 6 H 5 .CH.OH.CH.OHC 6 H 5 'i (C 6 H 5 ) 2 CH.CHO. 
 
 This is due to an atomic rearrangement opposite to that of the 
 transpositions of the unsym. diphenyl-chloro-ethanes and ethylenes just 
 indicated. It reminds one of the pinacolin rearrangement of the 
 pinacones. 
 
 Similarly we obtain from methyl- and ethyl-hydrobenzoin 
 C 6 H 5 CH(OH).C(Alk)OHC 6 H 5 : a, a-diphenyl-propion-aldehyde (C 6 H 5 ) 2 C 
 (CH 3 ).CHO, b.p. 12 176, and a, a-diphenyl-butyr-aldehyde (C 6 H 5 ) 2 C 
 (C 2 H 5 ).CHO, b.p. 314 (C. 1907, I. 726). 
 
 Unsym. diphenyl-aeetone (C6H 5 ) 2 CH.COCH 3 , m.p. 45 and 61 
 (dimorphous), oxime, m.p. 164, is formed on heating diphenyl-propy- 
 lene-glycol with dilute HC1 (B. 39, 2302). 
 
 Diphenyl-ketene (C 6 H 5 ) 2 C : CO, b.p. 12 146, a reddish-yellow 
 liquid solidifying in freezing mixture to straw-yellow crystals, is the 
 first and most closely studied representative of the interesting class of 
 the ketenes (Staudinger, 1905 ; cp. Vol. I.). It is formed by the action 
 of zinc upon diphenyl-chloracetic acid chloride, or by the withdrawal 
 of HC1 from diphenyl-acetic acid chloride by means of tertiary bases 
 (A. 356, 51). Its easy formation by heating azi-benzile with rejection 
 of N 2 and migration of a phenyl group is noteworthy (B. 42, 2346) : 
 
 C 6 H 5 \ C< /N C 6 H 5 \ / C H 5 
 
 C 6 H 5 CO/ XJR ~^~* C 6 H 5 CO/ \ C 6 H 5 
 
 a reaction which appears to correspond to the formation of stilbene 
 from diphenyl-monochloro-ethylene, and of tetraphenyl-ethylene from 
 benzo-pinacolin alcohol. 
 
 Diphenyl-ketene is more stable than the aliphatic representatives 
 of this class of bodies, and shows no tendency towards polymerisation ; 
 but it shows greater reactivity, (i) With water it forms diphenyl- 
 acetic acid or its anhydride. (2) With alcohols it forms diphenyl- 
 
606 ORGANIC CHEMISTRY 
 
 acetic ester. (3) With HC1 it forms diphenyl-acetic acid chloride. (4) 
 With NH 3 , phenyl-hydrazin, and primary and secondary bases it 
 forms the corresponding diphenyl-acetic acid derivatives. (5) With 
 organic acids we obtain mixed acid anhydrides. (6) With sodium- 
 malonic ester we obtain diphenyl-acetyl-malonic ester (C 6 H 5 ) 2 CH. 
 COCH(CO 2 R) 2 . (7) With phenyl-magnesium bromide we obtain 
 triphenyl-vinyl alcohol (C 6 H 5 ) 2 C : C.(OH)C 6 H 5 . (8) With Schiffs 
 bases it unites with formation of j3-lactones : 
 
 (C.H 5 ) 2 C=CO+C,H 6 CH=NC,H 
 
 (go) With a/?-unsaturated aldehydes and ketones we obtain, on heating 
 the components in indifferent solvents, unstable /Mactones which, in 
 the nascent state, decompose into CO 2 and multiple unsaturated 
 hydrocarbons (B. 42, 4249) : 
 
 (C 6 H 5 CH : CH) 2 CO + (C 6 H 6 ) 2 C : CO -- > (C 6 H 5 CH : 
 
 (C 6 H 5 CH : CH) 2 C : C(C 6 H 5 ) 2 , 
 
 (gb) The quinones react like the a/3-unsaturated ketones ; according to 
 the quantities used, mono- or dilactones of jS-oxy-acids are formed, 
 while the latter decompose at once into 2CO 2 and tetraphenyl-di- 
 methylene-quinones : 
 
 CO.C(C 6 H 6 ) 2 V /C(C 6 H 5 ) 2 .CO -co, 
 
 I O/ \O - (^6^5)2^ ^6 "4 (^e^sh- 
 
 The monolactones can be isolated, and are only split up into CO 2 an.d 
 diphenyl-quino-methanes on heating. 
 
 o-Substituents depress the reactivity of the quinone groups, so that 
 chloranile and anthraquinone no longer unite with diphenyl-ketene 
 (A. 380, 243). 
 
 Diphenyl-acetic acid (C 6 H 5 ) 2 CH.CO 2 H is formed from its nitrile 
 by saponification ; by reducing benzilic acid with hydriodic acid and 
 phosphorus in glacial acetic acid (A. 275, 84) ; and from diphenyl- 
 dichloro-ethylene by heating to 180 with Na alcoholate, a reaction 
 which may be generalised (A. 306, 79). The acid melts at 146. When 
 oxidised with a chromic acid mixture it yields benzo-phenone ; and 
 when heated with soda-lime we get diphenyl-methane. Its ethyl ester 
 melts at 58 ; the methyl ester at 60 ; and the chloride at 57. 
 
 Diphenyl-aceto-nitrile (C 6 H 5 ) 2 CH.CN results when diphenyl-bromo- 
 methane is heated with Hg(CN) 2 , or by the condensation of mandelic 
 nitrile, C 6 H 5 .CH(OH)CN, and benzene with tin tetrachloride (B. 25, 
 1615). It melts at 72 and boils at 184 (at 12 mm.). The hydrogen 
 of its CH group is readily replaced by the benzene residue, but not 
 by alkyls (A. 275, 87). Iodide, acting upon its sodium derivatives, 
 produces tetraphenyl-succino-nitrile. 
 
 p 2 -Ditolyl-, -dianisyl-, and -diphenetyl-aeetic acid, m.p. 144, 110, 
 and 114 (A. 306, 81). 
 
 Tetranitro-diphenyl- acetic acid 6 ^ 3( ^ 2 | 2 )>CH.co 2 H. The ethyl 
 ester is derived from dinitro-phenyl-aceto-acetic ester and dinitro- 
 
HOMOLOGOUS DI- AND POLY-PHENYL-PARAFFINS 607 
 
 phenyl-malonic ester by the action of o, p-dinitro-bromo-benzol, the 
 group CO.CH 3 (and CO 2 .C 2 H 5 ) being replaced. It may be similarly 
 prepared from dinitro-phenyl-acetic ester by the introduction of the 
 dinitro-phenyl residue. It melts at 154. Alcoholic potash or soda 
 converts the ester, by the substitution of the hydrogen of the CH 
 group, into brilliant metallic salts, dissolving in alcohol and water, 
 with a dark -blue colour. Compare tetranitro - phenyl - methane 
 [(C 6 H 3 NO 2 )2]CH 2 and trinitro-triphenyl-methane (C 6 H 4 NO 2 ) 3 CH (B. 
 21,2476). 
 
 p 2 -Diamido-diphenyl-aeetic acid [NHaCgHJaCHCOaH, m.p. 234, 
 is formed by the transposition of dianilido-acetic acid (C 6 H 5 NH)^ 
 CHCO 2 H, on heating with aniline and its chlorohydrate (B. 41, 3019, 
 
 3031)- 
 
 p-Oxy-diphenyl-acetie acid, m.p. 173, from mandelic acid or its 
 nitrile with phenol and sulphuric acid (73 per cent.), besides 0-oxy- 
 
 dipheayl-acetic lactone C 6 H 5 CH<^:^>O, m.p. 114. The latter yields 
 
 a bromine derivative easily transformed into o-oxy-diphenyl-glycocoll 
 HOC 6 H 4 C(C 6 H 5 )(NH 2 )COOH (B. 31, 2812). 
 
 Tetra-oxy-diphenyl-acetie acid COOH.CH[C 6 H 3 (OH)2] 2 has been 
 obtained by the condensation of chloral with resorcin by means of 
 potassium bisulphate. It has a yellow colour. It dissolves in cold 
 alkalies with a red colour, and forms a triacetyl derivative melting at 
 152 (B. 29, R. 776 ; C. 1897, II. 739). 
 
 Benzilie acid, diphenyl-gly colic acid (C 6 H 5 ) 2 C(OH).CO 2 H, m.p. 150, 
 is produced by a molecular rearrangement of benzile (q.v.) when digested 
 with alcoholic potassium hydroxide, and from diphenyl-acetic acid by 
 the action of bromine and boiling with water. We can prepare it 
 better by the action of aqueous potash and air upon benzoin (B. 19, 
 1868 ; C. 1902, I. 1012) : 
 
 C 6 H 5 COCOC 6 H 5 -J*~+ (C 6 H 5 ) 2 C(OH)COOH. 
 
 When heated above its melting-point, benzilic acid takes on a 
 blood-red colour, and dissolves with the same colour in sulphuric acid. 
 Diphenylene-diphenyl-ethane derivatives are produced by the action 
 of concentrated sulphuric acid upon benzilic acid (B. 29, 734). 
 
 With phosphorus chlorides benzilic acid yields diphenyl-ehloracetie 
 acid (C 6 H 5 ) 2 CC1C0 2 H, m.p. 119 with decomposition (B. 36, 145), and 
 diphenyl-ehioracetie acid chloride, m.p. 50 (A. 356, 72) ; with P 2 O 5 or 
 
 COC1 2 and pyridin we obtain benzilide (C 6 H 5 ) 2 C<(^^C(C 6 H 5 ) 2 , m.p. 
 
 196 (B. 35, 3642). It yields diphenyl-acetic acid when heated 
 with hydriodic acid and phosphorus. On distilling its barium salt it 
 breaks up into carbon dioxide and benzo-hydrol ; oxidation yields 
 benzo-phenone. 
 
 p-Tolilie acid (CH 3 C 6 H 4 ) 2 : C(OH)COOH ; anisilie acid (CH 3 OC 6 H 4 ) 2 
 C(OH)COOH; cuminilic acid (C 3 H 7 C 6 H 4 ) 2 C(OH)COOH ; and hexa- 
 methoxy-benzilie acid [(CHgO^CgH^qOHJCOOH are prepared, like 
 benzilic acid, from their corresponding substituted benziles. 
 
 j3,j3-Diphenyl-propionie acid (C 6 H 5 ) 2 CH.CH 2 .COOH is a homologue 
 of diphenyl-acetic acid. It melts at 149. It is formed by the addi- 
 tion of phenyl-magnesium bromide to cinnamic acid ester (C. 1905, I. 
 
608 ORGANIC CHEMISTRY 
 
 522). This is accomplished by means of sulphuric acid, just as phenol- 
 phenyl-ethane is obtained from styrol and phenol, or benzene is 
 attached to cinnamic acid. The continued action of the sulphuric 
 acid leads to a condensation to y-phenyl-hydrindone. The a-bromo- 
 j8,/3-diphenyl-propionic acid, m.p. about 164, and especially its potas- 
 sium salt, decompose on evaporating their aqueous solution into 
 CO 2 , HBr, and stilbene, a reaction corresponding to the formation of 
 this hydrocarbon from diphenyl-monochloro-ethylene (C. 1905, II. 
 1022). 
 
 Phenyl-tolyl- , phenyl-xylyl-propionic acids, etc., are prepared just 
 like diphenyl-propionic acid (B. 26, 1579). Potassium permanganate 
 oxidises these acids to benzo-phenone, phenyl-tolyl-ketone, phenyl- 
 xylyl-ketone, etc. 
 
 y, y-Diphenyl-butyric acid (C 6 H 5 ) 2 CHCH 2 CH 2 COOH, m.p. 107, 
 from y-phenyl-butyro-laetone or phenyl-iso-crotonic acid, with benzene 
 and A1C1 3 (C. 1907, II. 2045). 
 
 a, a-Diphenyl-propionic acid (C 6 H 5 ) 2 C(CH 3 )CO 2 H, m.p. 173, and its 
 homologues are obtained by condensation of phenyl-pyro-racemic acid 
 with benzene and its homologues by means of concentrated sulphuric 
 acid (B. 14, 1595). On heating with concentrated sulphuric acid they 
 split off CO and yield diphenyl-carbinols, which in turn easily decompose 
 into water and unsym. diaryl-ethylenes (B. 38, 839). 
 
 j8-Phenyl-cinnamie acid (C 6 H 5 ) 2 C : CH.CO 2 H, m.p. 162, is formed, 
 like j3-alkyl-cinnamic acids, from the condensation product of benzo- 
 phenone with bromacetic ester and zinc (B. 40, 4537 ; 41, 324), and 
 from a-bromo-/?, j8-diphenyl-propionic acid with alcoholic potash 
 (C. 1905, I. 522). 
 
 y-Diphenyl-itaeonic acid (C 6 H 5 ) 2 C : C(COOH).CH 2 .COOH, m.p. 
 169 with decomposition, is obtained by the condensation of benzo- 
 phenone with succinic ester through the agency of sodium ethylate. 
 The acid, on heating under reduced pressure, gives an anhydridf , m.p. 
 I47-I50, whose soda solution on acidulation yields diphenyl-eitraeonie 
 acid (C 6 H 5 ) 2 CHC(COOH) : CHCOOH, m.p. iio-ii5 with decom- 
 position. This acid is condensed by sulphuric acid to phenyl-indone- 
 acetic acid. With bromine it gives y-diphenyl-bromo-paraeonie acid 
 
 (C 6 H 5 ) 2 C.CBr(COOH).CH 2 .COO, which, on heating with water, passes 
 into y-diphenyl-aconic acid, m.p. 139, and further, with rejection of 
 
 CO 2 , diphenyl-croto-lactone (C 6 H 5 ) 2 C.CH : CH.COO, m.p. 131 (A. 
 308, 89). y-Diphenyl-a,j3-dichloro-crotonic acid (C 6 H 5 ) 2 CH.CC1 : CC1 
 COOH, m.p. 152, is formed from muco-chloric acid chloride (see Vol. 
 I.), benzene, and A1C1 3 (C. 1897, H- 57) y-Diphenyl-aeetaerylic ester 
 (C 6 H 5 ) 2 C : C(COCH 3 )COOC 2 H 5 , m.p. 76, from benzo-phenone chloride 
 and cu-aceto-acetic ester, yields by ketone splitting diphenyl-butenone 
 (C 6 H 5 ) 2 C : CHCOCH 3 , m.p. 33, b.p. 13 190 (B. 32, 1433), and homo- 
 logues are formed from triphenyl-chloro-methane and alkyl-magnesium 
 haloids (B. 39, 2957). 
 
 Triphenyl-acetaldehyde (C 6 H 5 ) 3 C.CHO, m.p. 223, from triphenyl- 
 magnesium chloride and formic acid ester. 
 
 Triphenyl-methyl-ethyl-ketone (C 6 H 5 ) 3 C.COC 2 H 5 , m.p. 104, from 
 triphenyl-acetic acid chloride and C 2 H 5 MgI (B. 43, 1137). 
 
 Triphenyl-acetic acid (C 6 H 5 ) 3 C.COOH is a very feeble acid. It melts 
 
HOMOLOGOUS DI- AND, POLY-PHENYL-PARAFFINS 609 
 
 at 264, and decomposes into triphenyl-methane-car boxy lie acids. It 
 is made by the action of benzene and aluminium chloride upon tri- 
 chloracetic acid, and when carbon dioxide is conducted over potassium 
 triphenyl-methane at 200. The nitrite is produced by the interaction 
 of triphenyl-chloro- or bromo-methane and mercuric cyanide Hg(CN) 2 
 (A. 194, 260 ; B. 28, 2782), or by deamidising hydrocyano-para- 
 rosanilin (B. 26, 2225). 
 
 P 3 - Triamido - triphenyl - acetic nitrile, hydrocyano-para-rosanilin, 
 results upon digesting para-rosanilin salts with alcohol and potassium 
 cyanide. Hydrocyano-rosanilin is similarly obtained from rosanilin 
 salts. According to Hantzsch, quinoid ammonium cyanides are first 
 generated, and these transpose themselves into nitriles in the solution 
 itself (B. 33, 287) : 
 
 (NH 2 .C 6 H 4 ) 2 C : C 6 H 4 : NH 2 CN - -> (NH 2 .C 6 H 4 ) 2 C(CN).C 6 H 4 .NH 2 . 
 
 The chlorohydrates of these hydrocyano-compounds decompose 
 on heating into HC1, HCN, and the rosanilin salts. 
 
 Substituted triphenyl-acetic acids, especially phenol derivatives, 
 are easily obtained from benzilic acid with phenols by condensation 
 with tin tetrachloride (B. 34, 3080 ; 37, 664 ; 40, 4060) : 
 
 Diphenyl-p-tolyl-acetic acid CH 3 [4]C 6 H 4 (C 6 H 5 ) 2 CCOOH, m.p. 205. 
 p-Tritolyl-acetic acid (CH 3 C 6 H 4 ) 3 C.CO 2 H, m.p. 227. p-Oxy-triphenyl- 
 acetic acid HO[4]C 6 H 4 (C 6 H 5 ) 2 CCOOH, m.p. 212. m- and p-Cresol- 
 
 diphenyl-acetic acid lactone A[2]C 6 H 3 (CH 3 )[i]C(C 6 H 5 ) 2 CO, m.p. 126 
 and 130. o- and m-Xylenyl-diphenyl-acetic acid lactone, m.p. 178 
 and 170. Thymoyl- and earvacroyl-diphenyl-acetic acid HO[4]C 6 H 
 
 (CH 3 )(C 3 H 7 )[i]C(C 6 H 5 )COOH, etc. 
 
 Diphenyl-methyl-quinol-earboxylie acid lactone (formula, see below), 
 colourless crystals, m.p. 143, is formed by condensation of diphenyl- 
 ketene with excess of quinone. On heating, it decomposes into CO 2 
 and diphenyl-quino-methane. As a quinol derivative it shows the 
 transposition into benzene derivatives with migration of the alkyl 
 group characteristic of these compounds ; thus, the above /Mactone 
 on illumination in the solid state or in boiling benzene solution passes 
 into the isomeric 2, 5-dioxy-triphenyl-aeetic acid lactone, m.p. 196 : 
 
 (C 6 H 5 ) a C CO 
 
 which has also been obtained synthetically from hydroquinone and 
 benzilic acid by means of SnCl 4 (A. 380, 248). 
 
 B. Sym. Diphenyl-ethane Group. Dibenzyl, sym. diphenyl-ethane 
 C 6 H 5 .CH 2 .CH 2 .C 6 H 5 , m.p. 52 and b.p. 284, is prepared (i) by the 
 action of sodium or copper upon benzyl chloride C 6 H 5 .CH 2 C1, or (2) 
 of A1C1 3 upon benzene and ethylene chloride or co-chlorethyl-benzene 
 (A. 235, 155) ; and (3) by heating its oxygen derivatives, benzoin and 
 benzile, and from the unsaturated hydrocarbons tolane and stilbene 
 VOL. II. 2 R 
 
6io ORGANIC CHEMISTRY 
 
 by reduction with Na and alcohol (B. 35, 2647), HI, or H and Ni at 
 220 (C. 1908, I. 469). Finally, it can be obtained (4) by oxidation 
 of toluol with potassium persulphate (B. 32, 2531). It forms stilbene 
 and tolane when heated to 500. Chromic acid and potassium per- 
 manganate oxidise it directly to benzoic acid. It yields two dinitro- 
 compounds by nitration. 
 
 p, p-Dinitro-dibenzyl has also been obtained by the action of 
 stannous chloride upon p-nitro-benzyl chloride. It melts at 181 
 (A. 238, 272 ; B. 20, 909). Also by the action of cold methyl-alcoholic 
 potash upon p-nitro-toluol (C. 1908, I. 642). o, o-Dinitro-dibenzyl, 
 m.p. 122 (C. 1910, II. 570). 
 
 p 2 -Diamido-dibenzyl can be used for the preparation of tetrazo- 
 dyes in the same way as diamido-stilbene (C. 1899, I- II 7 1 )- 
 
 Oo-Diamido-dibenzyl, m.p. 68, by reduction of o 2 --diamido-stilbene. 
 
 CH C H \ 
 
 On heating its chlorohydrate it gives imido-dibenzyl CH'C'H / NH> 
 m.p. 110, which contains a seven-membered ring (A. 305, 96). 
 
 Homologues of Dibenzyl. o 2 , m 2 , and p 2 -Dimethyl-dibenzyl, m.p. 
 66, 82, and 296, are produced by oxidation of o-, m-, and p-xylol 
 with potassium persulphate (B. 32, 2531). 
 
 a, j8-Diphenyl-propane C 6 H 5 CH(CH 3 )CH 2 C 6 H 5 , b.p. 28 167, by 
 reduction of a-methyl-stilbene. a, jS-Diphenyl-iso-butane C 6 H 5 CH 2 C 
 (CH 3 ) 2 C 6 H 5 , from iso-butylene bromide, benzene, and A1C1 3 (C. 1901, 
 II. 202). 
 
 a,-Phenyl-tolyl-propane C 6 H 5 CH(CH 3 )CH 2 C 6 H 4 CH 3 , and a,j8- 
 phenyl-xylyl-propane, are produced when concentrated sulphuric acid 
 acts upon styrol in the presence of xylene or trimethyl-benzene. The 
 homologous benzenes, containing a methyl group, attach themselves 
 to the unsaturated linkage in the styrol (B. 23, 3269). 
 
 Diphenyl-dimethyl-ethane C H ? .CH(CH 8 )CH(CH^C 6 H 5 , melting at 
 123, is formed when sodium or zinc dust acts upon a j8-haloid ethyl- 
 benzene C 6 H 5 .CHX.CH 3 (B. 26, 1710) ; also from ethyl-benzol with 
 persulphate (B. 32, 434). 
 
 Stilbene, toluylene, sym. diphenyl-ethylene C 6 H 5 .CH : CH.C 6 H 5 , 
 melting at 124' and boiling at 306, crystallises in large, glistening 
 (oTtAjSetv, to glisten) monoclinic leaflets or prisms. It is obtained by 
 a great variety of methods. It belongs to a long-known class of 
 aromatic substances (Laurent, 1844). It is produced : 
 
 (1) By distilling benzyl sulphide and disulphide. 
 
 (2) By heating polymeric thio-benzaldehyde to 150, or by distilling 
 trithio-benzaldehyde with metallic copper (B. 25, 600). 
 
 (3) By the action of metallic sodium upon benzaldehyde or benzal 
 chloride. 
 
 (4) From benzaldehyde and phenyl-acetic acid, instead of the 
 expected phenyl-cinnamic acid (/. pr. Ch. 2. 61, 169). 
 
 (5) By magnesium organic syntheses stilbene and its homologues 
 are formed from benzyl-magnesium chloride with benzaldehydes or 
 aromatic ketones, the benzyl-aryl-carbinols formed as primary pro- 
 ducts splitting off water (B. 37, 453, 1447). 
 
 (6) By heating iso-nitro-benzyl cyanide C 6 H 5 C(: NOOH)CN with 
 soda to high temperatures, whereby phenyl-iso-nitro-methane is first 
 formed, which splits off sodium nitrite and forms stilbene (B. 38, 502). 
 
HOMOLOGOUS DI- AND POLY-PHENYL-PARAFFINS 611 
 
 (7) From benzal-azin C 6 H 5 CH : N.N : CHC 6 H 5 and phenyl-diazo- 
 methane C 6 H 5 CHN 2 , by heating and rejection of nitrogen. 
 
 (8) From chlorinated, asymmetrical diphenyl-ethane derivatives 
 e.g. (C 6 H 5 ) 2 CH.CH 2 C1, (C 6 H 5 ) 2 CH.CC1 3 by a rearrangement caused 
 by heat or zinc dust "(B. 7, 1409 ; /. pr. Ch. 2, 47, 44). 
 
 (9) By the action of metallic copper, potassium sulphydrate (B. 24, 
 1776), or potassium cyanide (B. 11, 1219) upon stilbene dihalides. 
 
 (10) An interesting method for its production is that of distilling 
 fumaric and cinnamic phenyl esters (B. 18, 1945) : 
 
 C a O COj 
 
 C.H 5 OCOCH : CH.COOC,H 5 > C 6 H 5 .CH : CH.CO.OC.H, > C 6 H t .CH : CH.C.H, 
 
 Diphenyl- fumaric ester Phenyl-cinnamic ester Stilbene. 
 
 Compare also the decomposition of chloro-benzyl-desoxy-benzoin in 
 benzoyl chloride and stilbene. 
 
 As an unsaturated compound, stilbene can occur in a second stereo- 
 isomeric form. This iso-stilbene is a liquid, b.p. 12 143, and has a 
 pleasant flower-like odour. It is formed by the reduction of tolane or 
 iso-bromo-stilbene with zinc dust and alcohol (A. 342, 208), also from 
 the ordinary stilbene by illuminating by ultra-violet light in benzene 
 solution (B. 42, 4871), besides the polymeric distilbene C 2 gH 24 , m.p. 
 163 (B. 35, 4129). By traces of iodine or bromine, distillation at 
 ordinary pressure, or vapours of fuming nitric acid, it passes into the 
 stable solid stilbene. Its formation from tolane indicates for iso- 
 
 TTf C TT TTC f TT 
 
 stilbene the cis-configuration H ^' C " H 5 whereas ^ H 6 5 represents 
 
 the ordinary stilbene as a trans-configuration. 
 
 When heated with hydro-iodic acid stilbene yields dibenzyl. The 
 addition of halogens produces stilbene dihaloids, the haloid esters of 
 the hydro-benzoins. Chromic acid oxidises stilbene to benzaldehyde 
 and benzoic acid. Thionessal, tetraphenyl-thiophene (q.v.), is pro- 
 duced when stilbene is heated for several hours at 250, together with 
 sulphur. Phenanthrene is formed when stilbene is heated. 
 
 With N 2 O 3 and N 2 O 4 stilbene combines to form C U H 12 (N 2 O 3 ) and 
 C 14 H 12 (N 2 O 4 ) ; the former, on boiling with glacial acetic acid, is partly 
 decomposed and converted into the latter, which is to be regarded as 
 diphenyl-dinitro-ethane C 6 H 5 CH(NO 2 ).CH(NO 2 )C 6 H 5 , a-mod., m.p. 
 236 with decomposition, jS-mod., m.p. I50-i52 (B. 34, 3536). 
 
 On treating with alkali it splits off one molecule of nitrous acid and 
 passes into 7-nitro-stilbene C 6 H 5 CH : C(NO 2 )C 6 H 5 , m.p. 75, which is 
 also obtained by the condensation of phenyl-nitro-methane and 
 benzaldehyde by means of aliphatic base (B. 37, 4509), and by heating 
 with methyl-alcoholic potash and then with HC1 through a number of 
 intermediate products into the isomeric benzyl-monoxime C 6 H 5 COC 
 (NOH)C 6 H 5 (A. 355, 269). 
 
 a-Methyl-stilbene C 6 H 5 C(CH 3 ) : CHC 6 H 5 , m.p. 83, b.p. 26 183, and 
 a-ethyl-stilbene, m.p. 57, b.p. 296, from desoxy-benzoin with 
 CH 3 MgI and C 2 H 5 MgI ; also from aceto-phenone with C 6 H 5 CH 2 MgCl 
 (B. 37, 457, 1450 ; C. 1904, II. 1038). 
 
 Stilbenes having the substituents in the benzene nucleus are 
 obtained from substituted benzyl and benzal chlorides ; also by 
 condensation of substituted benzaldehydes with phenyl-acetic acid ; 
 or of o-chloro-benzal chloride with copper. 
 
612 ORGANIC CHEMISTRY 
 
 o, o-Dichloro-stilbene (C1.C 6 H 4 .CH) 2 , m.p. 97; and chloro-nitro- 
 benzyl chloride and alcoholic potash give rise to diehloro-nitro-stilbene, 
 m.p. 294 (B. 25, 79 ; 26, 640). 
 
 o, p-Dinitro-stilbene (NO 2 ) 2 [2, 4]C 6 H 3 CH : CHC 6 H 5 , m.p. 140, from 
 benzaldehyde and o, p-dinitro-toluol by means of piperidin, give by 
 partial reduction with ammonium sulphide o-nitro-p-amido-stilbene, 
 m.p. in , and with stannous chloride o-amido-p-nitro-stilbene, m.p. 
 143, and further o, p-diamido-stilbene, m.p. 120 (B. 34, 2842). 
 
 The action of alcoholic potash upon o- and p-nitro-benzyl chlorides 
 gives rise to two physical isomerides in each case : two o, o-dinitro- 
 stilbenes, melting at 126 and 196 respectively, and two p, p-dinitro- 
 stilbenes, melting at 2io-2i6 and 28o-284 (B. 21, 2072 ; 23, 
 1959 ; 26, 2232), which yield corresponding diamido-stilbenes upon 
 reduction. 
 
 p 2 -Dinitro-stilbene-disulphonic acid is formed by the oxidation of 
 p-nitro-toluol-sulphonic acid with alkaline hypochlorite ; oo'-dinitro- 
 dibenzyl-disulphonic acid is first formed, and on further oxidation 
 p-nitro-benzal-dehydro-o-sulphonic acid (C. 1898, II. 94 ; C. 1900, I. 
 1085). 
 
 oo'-Diamido-stilbene, melting (cis-) at 123 and (trans-) at 168, 
 changes to indol on heating equivalent quantities of the hydro- 
 chloride and base ; aniline is eliminated (B. 28, 1411 ; but see 
 o 2 -Diamido-dibenzyl). The disulphonic acid of p 2 -diamido-stilbene 
 (melting at 227), by diazotising and combining with phenol, passes 
 into a tetrazo-compound, brilliant yellow. The mono-ethyl derivative 
 CH.C 6 H 3 (S0 3 H)N : NC 6 H 4 OH 
 
 of the latter is the substantive cotton- 
 CH.C 6 H 3 (S0 3 H)N : NC 6 H 4 OC 2 H 6 
 
 dye chrysophenin (B. 27, 3357). See B. 22, R. 311 (cp. benzidin dyes), 
 for additional dye-substances. On the electrolytic reduction of nitro- 
 stilbenes to cyclic azoxy- and azo-stilbenes, see C. 1903, I. 1414. 
 
 o-Oxy-stilbene, m.p. 147 (B. 42, 825). 
 
 p-Oxy-stilbene, m.p. 189, see A. 349, 107. 
 
 o, o'-Dioxy-stilbene, m.p. 92, is formed with other products from 
 salicyl aldehyde on boiling with zinc dust and glacial acetic acid (B. 24, 
 
 3175). 
 
 p 2 -Dioxy-stilbene, m.p. 281, is obtained as unsym. diphenol- 
 trichloro-ethane (HO[4]C 6 H 4 ) 2 CHCC1 3 , the condensation product of 
 phenol and chloral, by treatment with zinc dust or iron powder. By 
 attaching bromine at low temperatures it gives p 2 -dioxy-stilbene 
 dibromide, possessing the character of a pseudo-phenol-alcohol bromide. 
 On treatment with sodium acetate it splits off 2HBr and yields stilbene- 
 quinone, O : C 6 H 4 : CH.CH : C 6 H 4 : O, bright-red crystals, which can 
 also be obtained direct from the p 2 -dioxy-stilbene by oxidation with 
 PbO 2 or FeCl 3 , and resembles in its chemical behaviour the simple 
 methylene-quinones (A. 335, 157 ; B. 39, 3490). At higher tempera- 
 tures chlorine and bromine act upon p 2 -dioxy-stilbene as substituents, 
 forming tetrachloro- and tetrabromo-p 2 -dioxy-stilbene dichloride and 
 dibromide respectively, which, on treatment with alkali, pass into 
 tetrabromo- and tetrachloro-stilbene-quinone O : (C 6 C1 2 H 2 ) : CH.CH : 
 (C 6 C1 2 H 2 ) : O. These products are sparsely soluble and resemble 
 phosphorus (A. 325, 19). 
 
ALCOHOL AND KETONE DERIVATIVES OF DIBENZYL 613 
 
 3, 4rMethylene-dioxy-stilbene CH 2 O 2 C 6 H 3 CH : CHC 6 H 5 , m.p. 96, 
 from piper onal and benzyl-magnesium chloride (B. 37, 1431). 
 
 Tolane, diphenyl-acetylene C 6 H 5 .C : C.C 6 H 5 , m.p. 60, is produced 
 from stilbene dibromide on boiling with alcoholic potash, and, further, 
 together with diphenyl- vinyl ether, on treating unsym. diphenyl- 
 chloro-ethylene (C 6 H 5 ) 2 C : CHC1 with sodium alcoholate. 
 
 The latter method proceeds more smoothly with the substituted 
 tolanes. Dimethyl-tolane, m.p. 136, and dimethoxy-tolane, m.p. 145, 
 are obtained from ditolyl- and dianisyl-chloro-ethylene. 
 
 o, o'-Dichloro-tolane, m.p. 89, is made from o, o'-dichloro-stilbene 
 dichloride. 
 
 Tetrachloro-p-dioxy-tolane, m.p. 226, see A. 338, 236. 
 
 The tolanes absorb two and four halogen atoms, the products being 
 tolane di- and tetrachlorides (q.v.). The elements of water are taken 
 up by the action of glacial acetic acid and sulphuric acid, with the 
 formation of desoxy-benzoins (below) (cp. Vol. I.). 
 
 The action of nitrous acid gas upon tolane produces a- and - 
 diphenyl-dinitro-ethylene C 6 H 5 C(NO 2 ) : C(NO 2 )C 6 H 5 , m.p. i86-i87 
 and io5-io7 (B. 34, 619). p 2 -Diamido-tolane, m.p. 235, and trans- 
 formation products, see A. 325, 67. 
 
 ALCOHOL AND KETONE DERIVATIVES OF DIBENZYL. 
 
 C 6 H 5 CHOH C 6 H 5 CO C 6 H 5 CHOH C,H 5 CO C 6 H 5 CO 
 
 C 6 H 5 CH 2 C 6 H 5 CH 2 C 6 H 5 CHOH C G H 5 CHOH C 6 H 3 CO 
 
 Stilbene hydrate Desoxy-benzoin Hydro-benzoin Benzoin Benzile. 
 
 Stilbene hydrate, benzyl-phenyl-carbinol C 6 H 5 .CH(OH).CH 2 .C 6 H 5 , 
 m.p. 62, results upon reducing desoxy-benzoin with sodium amalgam, 
 and from the action of benzaldehyde upon benzyl-magnesium chloride. 
 Similarly, benzyl-phenyl-methyl-earbinol C 6 H 5 .C(OH)(CH 3 ).CH 2 C 6 H 5 , 
 m.p. 51, b.p. 15 175, is obtained from benzyl-magnesium chloride with 
 aceto-phenone, or from desoxy-benzoin with CH 3 MgI ; the latter 
 carbinol splits off water with greater difficulty than does the former 
 (B. 37, 456, 1450). 
 
 Desoxy-benzoin, phenyl-benzyl-ketone C 6 H 5 .CO.CH 2 .C 6 H 5 , m.p. 60 
 and b.p. 314. It is obtained by distilling a mixture of calcium 
 benzoate and calcium a-toluate ; also by the action of A1C1 3 upon a 
 mixture of alpha-toluic chloride ; by reducing benzoin with zinc and 
 hydrochloric acid (B. 21, 1296 ; 35, 912) ; from chloro-benzile and 
 benzile (B. 26, R. 585) by the action of hydriodic acid or zinc and HC1 ; 
 and by heating monobromo-stilbene with water to i8o-i9O. One 
 H atom of its CH 2 group can be replaced by sodium and alkyls, but 
 not the second (B. 21, 1297 ; 23, 2072). Methyl-, iso-butyl-, cetyl- 
 desoxy-benzoln melt at 58, 78, and 76 (B. 25, 2237). 
 
 Its oxime melts at 98. Iso-nitroso-desoxy-benzo'in, produced by 
 N 2 O 3 , is identical with a-benzile-monoxime. Hydriodic acid converts 
 desoxy-benzoin into dibenzyl ; see also stilbene hydrate. 
 
 The nitration of desoxy-benzoin produces o-nitro-desoxy-benzom 
 C 6 H 4 (NO 2 )CH. 2 .CO.C 6 H 5 , which, upon reduction, yields a-phenyl- 
 indol C 6 H 4 <c.c 6 H 5 . Desoxy-toluom CH 3 .C 6 H 4 .CH 2 .CO.C 6 H 4 .CH 3 , 
 
614 ORGANIC CHEMISTRY 
 
 and desoxy-anisoin CH 3 O.C 6 H 4 .CH 2 .CO.C 6 H 4 .OCH 3 , are formed from 
 the corresponding tolanes (A. 279, 335, 339) (above). CSC1 2 , or 
 carbon disulphide, and caustic potash, convert the desoxy-benzoins 
 into desaurins, which form brilliant golden-yellow needles. They 
 dissolve in sulphuric acid with a violet-blue colour. The exact con- 
 stitution of these bodies is not yet known. The simplest desaurin 
 very probably has the composition C 6 H 5 COC(CS)C 6 H 5 (B. 25, 1731, 
 2239). Cp. B. 37, 1599. Mono- and polyoxy-desoxy-benzoms, see 
 M. 26, 927. 
 
 Hydro-benzoin, toluylene-glycol C 6 H 5 .CH(OH)CH(OH)C 6 H 5 , has two 
 asymmetric C atoms, and occurs in two optically inactive modifications 
 (A. 259, 100) : hydro-benzoin, m.p. 134, and iso-hydro-benzo'in, m.p. 119. 
 The latter has been resolved into two optically active components 
 (see below). Both are produced, together with benzyl alcohol, when 
 zinc and alcoholic hydrochloric acid act upon oil of almonds, or when 
 the latter is treated with sodium amalgam, or in the electrolytic reduc- 
 tion of benzaldehyde (B. 29, R. 229). Both are also obtained from 
 stilbene bromide or chloride on converting the latter by silver acetate 
 or benzoate into esters, and saponifying these with alcoholic ammonia. 
 With potassium acetate, iso-hydro-benzoin is almost the sole product. 
 Hydro-benzoin predominates (with a little iso-hydro-benzoin) when 
 sodium amalgam acts on benzoin. This is also the best method for 
 its preparation (A. 248, 36). 
 
 Hydro-benzoin dissolves with difficulty in water, crystallises in 
 rhombic plates, melting at 134, and sublimes without decomposition. 
 The diacetate is obtained from benzaldehyde and acetyl chloride by 
 means of zinc dust (B. 16, 636) ; it melts at 134. 
 
 Iso-hydro-benzo'in is more readily soluble in water. It crystallises 
 in prisms which contain water of crystallisation and rapidly effloresce 
 on exposure. Its diacetate is dimorphous, and crystallises in shining 
 leaflets, melting at 118, or in rhombic prisms, melting at 106. 
 
 C 6 H 5 CH.O.CH.C 6 H 5 
 
 Dimolecular anhydrides \ (?), melting at 132 and 
 
 C 6 H 5 .CH.O.CH.C 6 H 5 
 
 102, are obtained, together with diphenyl-acetaldehyde (C 6 H 5 ) 2 CH. 
 CHO, from both hydro-benzoins by the action of sulphuric acid or P 2 O 5 . 
 
 By crystallisation from ether iso-hydro-benzoin has been resolved 
 into enantiomorphous dextro- and Isevo-rotatory crystals (B. 30, 1531). 
 Chromic acid or potassium permanganate changes both hydro-benzoins 
 into benzaldehydes, and nitric acid converts them into benzoin (B. 24, 
 1776). PBr 5 changes both to the same stilbene dibromide C 6 H 5 .CHBr. 
 CHBr.C 6 H 5 , melting at 237, which has also been made by the action 
 of bromine upon stilbene and dibenzyl. Stilbene and bromine yield 
 not only the body (the a-) melting at 237, but also a j8-variety, melting 
 at no . This is more readily soluble. It passes into the higher-melting 
 variety under the influence of heat, and this again reverts by alcoholic 
 potash into liquid monobromo-stilbene, whereas the /^-modification 
 by similar treatment changes to a solid monobromo-stilbene (B. 28, 
 2693) . Both hydro-benzoins are changed by PC1 5 into a- and /3-stilbene 
 dichloride, melting at 192 and 93. The a-compound is also produced 
 when chlorine acts upon stilbene dissolved in chloroform. When 
 heated to 200 the j8- passes into the a-variety. 
 
ALCOHOL AND KETONE DERIVATIVES OF DIBENZYL 615 
 
 Diphenyl-oxethylamine C 6 H 5 .CH(OH)CH(NH 2 )C 6 H 5 , melting at 163, 
 and iso-diphenyl-oxethylamine, melting at 129, are produced together 
 by the reduction of benzoin-oxime, also from benzaldehyde and benzyl- 
 amine, as well as by the condensation of benzaldehyde and glycocoll, 
 together with phenyl - a - amido - lactic acid. This last reaction is 
 explained by the condensation of benzaldehyde with benzylidene- 
 glycocoll in two directions according to the following scheme : 
 
 T C 6 H 5 CH : NCHCOOH . C 6 H 5 CHN : CHCOOH 
 
 HO.CHC 6 H 5 - C ' H5CI ' H2CC ^C 6 
 
 I. is split up into benzaldehyde and phenyl-amido-lactic acid ; II. into 
 glyoxylic acid and diphenyl-oxethylamine. The two isomeric 
 diphenyl-oxethylamines can be separated by means of their benzylidene 
 compounds. Nitrous acid converts them both into iso-hydro-benzoin. 
 Iso-diphenyl-oxethylamine has been split up into optically active 
 components, [a] D = 109-6 (A. 307, 79; B. 32, 2377; 36, 976). 
 The quaternary ammonium bases obtained from the two dimethyl- 
 oxethyl - amines by thorough methylation have the formula 
 C6H 5 CH(OH).CH(C ? H 5 )N(CH 3 ) 3 OH, and are broken up by heating 
 with water into trimethylamine, water, and diphenyl-ethylene oxide 
 C 6 H 5 CH.O.CHC 6 H 5 , m.p. 69, and iso-diphenyl-ethylene oxide, m.p. 
 42 (B. 43, 884). 
 
 Diphenyl - ethylene - diamine, stilbene-diamine C 6 H 5 CH(NH 2 )CH 
 (NH 2 )C 6 H 5 , melting at 91, is produced by reducing benzile-dioxime 
 with sodium and alcohol. It is resolved by crystallisation of its 
 bitartrate into two optically active components (B. 28, 3167). 
 
 The reduction of diphenyl-dinitro-ethanes and ethylenes with zinc 
 dust and acetic acid produces tetraphenyl-diethylene-diamine, tetra- 
 phenyl-piperazin NH[CH(C 6 H 5 ).CH(C 6 H 5 )]NH (B. 34, 627). 
 
 The dieso - anhydride of an o, o - dioxy - hydro - benzoin 
 
 O.C 6 H 4 .CH.CH.C 6 H 4 O, has been obtained in two modifications, melting 
 
 at 68 and 114, by the reduction of salicyl-aldehyde with zinc dust 
 and glacial acetic acid. 
 
 Benzoin, benzoyl-phenyl-carbinol C 6 H 5 .CH(OH).CO.C 6 H 5 , melting 
 at 134, is produced when the hydro-benzoins are oxidised with 
 concentrated nitric acid, and by the condensation of two molecules 
 of benzaldehyde with potassium cyanide in aqueous alcoholic 
 solution. 
 
 This reaction is also shown by other aromatic aldehydes (see B. 25, 
 293 ; 26, 60 ; C. 1908, II. 1689). The products are ketone alcohols 
 e.g. aniso'in CH 3 O.C 6 H 4 CH(OH)CO.C 6 H 4 .OCH 3 ; cuminom, etc., from 
 anisic aldehyde, cuminol (see Furfurol, Phenyl-glyoxal) and reduce 
 Fehling's solution, being at the same time oxidised to the corresponding 
 benziles. 
 
 d- and 1-Benzoin have been obtained by transformation of d- and 
 1-mandelic acid amide with phenyl-magnesium bromide (C. 1909, 
 
 II. 2005). 
 
 Chromic acid oxidises benzoin to benzaldehyde and benzoic acid, 
 while nitric acid changes it to benzile ; nascent hydrogen reduces it 
 to hydro-benzoin. The latter and benzile are produced when benzoin 
 
616 ORGANIC CHEMISTRY 
 
 is boiled with alcoholic potash. If air be simultaneously introduced, 
 benzile is the chief product, and it is further changed to benzilic acid. 
 By heating with concentrated alkali it is partly split up into benzyl 
 alcohol and benzoic acid. Prolonged action also yields hydro-benzoin, 
 stilbene hydrate, etc. (B. 35, 1982). 
 
 Benzoin hydrazone melts at 75 (/. pr. Ch. 2, 52, 124). Semi- 
 carbazone, m.p. 206 (A. 339, 257). The phenyl-hydrazones melt at 
 158 and 106 (B. 28, R. 788) ; the a-oxime at 152, the -oxime at 
 99 ; by oxidation with chromic acid the acetyl-/3-benzoin-oxime 
 passes into the acetyl-y-benzile-oxime, which determines its configura- 
 tion (B. 38, 69). 
 
 Alcohols and hydrochloric acid alkylise benzoin : methyl-benzoin 
 C 6 H 5 CH(OCH 3 )COC 6 H 5 melts at 50, and ethyl-benzoin at 62 (B. 26, 
 2412). Iso-propyl-benzom, m.p. 72-75 (B. 26, 2412; C. 1700, 
 
 I- 454)- 
 
 The HC1 ester of benzoin, desyl-chloride C,3H 5 CHC1COC 6 H 5 , m.p. 
 68, is formed by heating of benzoin with thionyl chloride (B. 42, 
 
 2348). 
 
 Desyl-bromide C 6 H 5 .CHBrCOC 6 H 5 , m.p. 55, is obtained from 
 desoxy-benzoin (see below) and bromine. Aniline converts it into 
 desyl-anilide, benzom-anilide C6H 5 CH(NHC 6 H 5 )CO.C 6 H 5 , m.p. 99, 
 which is also produced when aniline is heated together with benzoin. 
 When heated together with aniline hydrochloride to 160, the product 
 is benzom-anile-anilide C 6 H 5 CH(NH.C 6 H 5 )C(NC 6 H5)C 6 H 5 , m.p. 125 ; 
 and when with aniline and zinc chloride at still higher temperatures, 
 
 NH.C 6 H 4 
 
 diphenyl-indol I I (B. 26, 1336, 2640). 
 C 6 H 5 C=C.C 6 H 5 
 
 Benzom-p-toluide C 6 H 5 CH(NHC 6 H 4 .CH 3 )CO.C 6 H 5 , m.p. 145, is 
 formed in the condensation of benzaldehyde-toluidin by means of 
 potassium cyanide (B. 29, 1736). o-Diamines and benzoin condense 
 to dihydro-quinoxalins ; urea and thio-ureas with benzoin yield gly- 
 oxalins, while oxazoles are produced in the condensation of benzoin 
 with acid nitriles. For the condensation products of benzoin with 
 acetone and aceto-phenone, consult B. 26, 65. 
 
 Benzile, dibenzoyl, diphenyl-glyoxal C 6 H 5 .CO.CO.C 6 H 5 , m.p. 90 
 and b.p. 347, consists of beautiful yellow prisms. It is the most 
 easily obtained a-diketone. It is produced on boiling stilbene bromide 
 with water and silver oxide, and by digesting benzoin with concen- 
 trated nitric acid. 
 
 /yNH\ 
 
 Benzile andhydrazin hydrate form hydra-benzile C 6 H 5 cl <^ | JCO.C 6 H 6 
 
 C 6 H 5 C( 
 
 and bis - hydrazi - benzile C 6 H 5 C <J , which yield azi - benzile 
 
 / / N \ / / N \l 
 
 C 6 H 5 d<J|jco.C 6 H 5 and bis-azi-benzile c.H 5 .cmij on oxidation 
 
 (B. 29, 775). On heating in indifferent solvents the azi-benzile 
 decomposes into nitrogen and diphenyl-ketene (B. 42, 2346). Benzile- 
 mono-semi-earbazone, m.p. 175, heated with alcohol, splits off water 
 and forms diphenyl-oxytriazin ; benzile-di-semi-carbazone, m.p. 244 
 (A. 339, 243). 
 
ALCOHOL AND KETONE DERIVATIVES OF DIBENZYL 617 
 
 Benzile-osazone (C 6 H 5 ) 2 .C 2 (NNH.C 6 H 5 ) 2 , m.p. 225, becomes tri- 
 phenyl-oso-triazole on heating (A. 232, 230 ; B. 26, R. 198). An iso- 
 meric modification of benzile-osazone, m.p. 208, has been obtained by 
 the action of iodine and sodium ethylate upon benzal-phenyl-hydra- 
 zone. Derivatives have been similarly obtained. When heated above 
 its melting-point it changes to the higher-melting modification (B. 29, 
 R. 863 ; 35, 3519 ; A. 305, 170; 324, 310 ; C. 1909, I. 739). 
 
 One molecule of hydroxylamine, acting upon benzile, produces two 
 isomeric monoximes, the a- melting at 134, and the y- at 113. The 
 former passes into the latter by heating it to 100 with alcohol, or 
 upon dissolving it in glacial acetic acid with hydrochloric acid. 
 
 a-Monoxime and hydroxylamine form a-benzile-dioxime, while the 
 y-monoxime yields y-benzile-dioxime (B. 22, 540, 709). Compare B. 26, 
 792, R. 52, for their behaviour with phenyl-hydrazin. 
 
 Both monoximes break down, upon heating, into benzo-nitrile and 
 benzoic acid. The behaviour of the benzile-monoximes in the Beckmann 
 oxime rearrangement is very interesting. It is effected by means of 
 PC1 5 : a-monoxime (i) yields benzoyl-benzimide chloride (2), readily 
 decomposing into benzo-nitrile and benzoyl chloride, while the y-mon- 
 oxime (3) yields benzoyl-formic-acid, anilide chloride (4) (A. 296, 279 ; 
 B. 37, 4295) : 
 
 (i) C 6 H 5 CCOC 6 H 5 (2) C 6 H 5 CC1 (3) C 6 H 5 CCOC 6 H 5 (4) C1CCOC 6 H 5 
 
 NOH ttCOCH; HON * CHtt 
 
 In the first instance the hydroxyl exchanged positions with the 
 phenyl residue, in the second with the benzoyl residue, which led to 
 the above accepted configuration of the monoximes. 
 
 Two molecules of hydroxylamine convert benzile into two isomeric 
 benzile-dioximes, the a- melting at 237, and the /?- at 207. A third 
 y-benzile-dioxime has been prepared from y-benzile-monoxime ; it 
 melts at 163. The ^-dioxime is the most stable ; the other modifica- 
 tions rapidly change to it. Under certain conditions the y-dioxime 
 rearranges itself into the a-form (A. 274, 33). 
 
 Three different esters are produced with acid anhydrides : benzile- 
 dioxime diacetates the a-form melting at 148, the j8- at 124, and the 
 y- at 114. Sodium hydroxide saponifies the a- and jS-diacetates to 
 
 C H C * N 
 their oximes, while the y-acetate yields the anhydride 6 | ^>O, 
 
 v^^JriE\w/ I JN 
 
 diphenyl-furazane (q.v.), which also results from all three dioximes by 
 the exit of water. Potassium ferricyanide, in alkaline solution, oxidises 
 
 C 6 H 6 C=N O 
 all three to the peroxide \ \ , melting at 114. This, when 
 
 O 6 HgC = N O 
 rapidly distilled, breaks down into two molecules of phenyl cyanate. 
 
 A complete picture is also afforded by the behaviour of the three 
 dioximes in the Beckmann rearrangement, which has led to a formula 
 for the present case of isomerism on the assumption that the oxime 
 hydroxyls invariably exchange positions with the atomic groups 
 adjacent to them (A. 274, i) : 
 
 I. a-Benzile-dioxime yields chlorides with PC1 5 by a change in 
 position first of the one and then of the second hydroxyl, which can be 
 converted into the anhydrides : dibenzenyl-azoxime and diphenyl-oxy- 
 
618 ORGANIC CHEMISTRY 
 
 biazole (q.v.), whose hydrates are included in the following diagram for 
 the sake of clearness : 
 
 C 6 H 5 C C.C 6 H 6 C 6 H 5 COJH HO|N N N 
 
 II II > II II > II II 
 
 N.OH HON N CC 6 H 5 C 6 H 5 .CQ|H HO|C.C 6 H 5 
 
 a-Benzile-dioxime Dibenzenyl-azoxime Diphenyl-oxy-biazole. 
 
 II. y-Benzile-dioxime in the first stage of the reaction also yields 
 dibenzenyl-azoxime, but by a second change in position phenyl-benzoyl- 
 urea is produced : 
 
 C 6 H 5 C C.C 6 H 6 HO.C N 
 
 II II > II II 
 
 HO.N HON C 6 H 5 .N HOC.C 6 H 5 
 
 y-Benzile-dioxime Phenyl-benzoyl-urea (pseudo-form). 
 
 III. j8-Dioxime by a double change in position yields oxanilide : 
 
 CjHgC C.CgHg HOC COH 
 
 II II > II II 
 
 HO.N N.OH C 6 H 5 .N NC 6 H 5 
 
 y-Benzile-dioxime Oxanilide. 
 
 The ready transition of the y-diacetate into furazane is not in 
 harmony with the preceding configuration of the dioximes ; this might 
 rather be expected from the a-diacetate. 
 
 The analogy of the benzile-dioximes with the osazones of dioxo- 
 succinic ester is rather remarkable (I. 528). These osazones also occur 
 in three forms, one of which is stable and the other two unstable, 
 so that the assumption of similar causes for the isomerism is not yet 
 excluded (B. 28, 64). 
 
 Aniline and benzile heated to 200 yield benzile-monanile C 6 H 5 CO. 
 C(NC 6 H 5 )C 6 H 5 , melting at 106 ; on adding P 2 O 5 the product is benzile- 
 dianile C 6 H 5 C(NC 6 H 5 )C(NC 6 H 5 )C 6 H 5 , melting at 142 (B. 25, 2600 ; 
 26, R. 700). Benzile, being an o-diketone, is particularly well adapted 
 for the formation of heterocyclic rings. It condenses with ethylene- 
 diamine to a dihydw-pyrazine derivative, with ortho-diamines to 
 quinoxalins, with o-amido-diphenylamine to a stilbazonium base (see 
 this), with ureas and thio-ureas to ureins and diure'ins, with semi- 
 carbazide to o%y-diphenyl-triazine, etc. Hydriodic acid reduces it to 
 desoxy-benzoin, while chromic acid oxidises it to benzoic acid. On 
 standing with potassium cyanide and alcohol it breaks down into 
 benzoic acid and benzaldehyde. See B. 28, R. 465 ; 29, R. 645, 865 ; 
 C. 1897, I. 596 ; 1903, I. 877 ; 1905, II. 243, for the condensation of 
 benzile with malonic ester and aceto-acetic ester. 
 
 The conversion of benzile into benzilic acid by fusion with caustic 
 potash or upon boiling with alcoholic potash is important : 
 
 C 6 H 5 COCOC 6 H 5 -5~* (C 6 H 5 ) 2 C(OH)COOH. 
 
 Phosphorus pentachloride changes benzile to ehloro-benzile C 6 H 5 . 
 COCC1 2 C 6 H 5 , m.p. 61, and, later, to tolane tetrachloride C 6 H 5 CC1 2 CC1 2 
 C 6 Hg, m.p. 163. The latter has also been obtained synthetically on 
 heating benzo-trichloride with copper, whereas benzile is produced 
 when it is heated together with glacial acetic acid or sulphuric acid. 
 
 As benzile is obtained from benzoin, so anisile (CH 3 O.C 6 H 4 CO) 2 , 
 
ALCOHOL DERIVATIVES OF STILBENE 619 
 
 melting at 133, cuminile (C 3 H 7 .C 6 H 4 CO) 2 , melting at 84, have been 
 prepared by the action of nitric acid upon anisoin and cuminoin. Ani- 
 sile and a hexamethoxy-benzile [(CH 3 .O) 3 C 6 H 2 CO] 2 , m.p. 189, have 
 been obtained by alkaline reducing agents from anisamide and tri- 
 methyl-gallamide (B. 24, R. 523). 
 
 These benziles, when fused with caustic potash, yield : 
 
 Anisilic acid, cumilic acid, and hexamethoxy-benzilic acid (see 
 above) . 
 
 The osazones of several substituted benziles, like salicile, cuminile, 
 anisile, piperile, like benzile-osazone itself, have been obtained by the 
 action of atmospheric oxygen upon the alkaline alcoholic solutions of 
 the phenyl-hydrazones of the corresponding aldehydes : salicyl-alde- 
 hyde, piperonal, etc. (A. 308, i). 
 
 p 2 -Tetramethyl-diamido-benzile (CH 8 ) 2 NC 6 H 4 .CO.COC 6 H 4 N(CH 3 ) 2 , 
 m.p. 198, is obtained by heating oxalyl chloride with excess of 
 dimethyl- aniline (B. 42, 3487). 
 
 ALCOHOL DERIVATIVES OF STILBENE are not known in a free 
 condition ; when their esters are saponified, isomeric ketones are 
 obtained for the most part (see Phenyl-vinyl alcohols) : 
 
 Bromo-stilbene C 6 H 5 CBr : CHC 6 H 5 -Jl? > C 6 H 5 CO.CH 2 C 6 H 5 benzofn" 
 
 Iso-benzile C 6 H 5 C(OCOC 6 H 6 ) : C(OCOC 6 H 5 )C 6 H 5 -> C 6 H 5 CO.CH(OH)C 5 H 5 Benzoin. 
 
 However, benzoin reacts in most cases as if it were an unsaturated 
 glycol with the formula C 6 H 5 C(OH) : C(OH)C 6 H 5 . 
 
 Monoehloro-stilbene C 6 H 5 CH : CC1.C 6 H 5 is an oil boiling at 320- 
 324. It is produced when PC1 5 acts upon desoxy-benzom, and by 
 the action of alcoholic potash on stilbene dichloride. When boiled 
 with glacial acetic acid it is transformed into an isomeric modification, 
 melting at 54. Chlorine and bromine convert it into ehloro-stilbene 
 dichloride C 6 H 5 CC1 2 .CHC1.C 6 H 5 , m.p. 103, and chloro-stilbene di- 
 bromide, m.p. 127 (C. 1897, I. 858). Methyl-chloro-stilbene C 6 H 5 C 
 (CH 3 ) : CC1C 6 H 5 is obtained from methyl-desoxy-benzoin, and behaves 
 similarly. It is an oil, and melts at 118 (B. 25, 2237 ; 29, R. 34). 
 Monobromo-stilbene, m.p. 31, results on treating jS-stilbene dibromide, 
 m.p. 110, with alcoholic potash ; whereas the stilbene dibromide, m.p. 
 237, yields an iso-bromo-stilbene, m.p. 19. On the application of 
 heat the latter passes into the solid isomeride. Reduction with zinc 
 and alcohol converts iso-bromo-stilbene into liquid iso-stilbene. 
 
 Diacetyl-dioxy-stilbene, stilbene-glycol diacetate C 6 H 5 C(OCOCH 3 ) : 
 C(OCOCH 3 )C 6 H 5 , a-modification, m.p. 153, ^-modification, m.p. 110, 
 is formed by the reduction of benzile in acetic anhydride and sulphuric 
 acid with zinc dust (A. 306, 142). 
 
 Iso-benzile, stilbene-glycol dibenzoate C 6 H 5 C(O.COC 6 H 5 ) : C(OCOC 6 Hg) 
 C 6 H 5 , colourless needles, m.p. 156, is obtained by the action of metallic 
 sodium upon the ethereal solution of benzoyl chloride (Vol. I.). It is 
 a polymeride of benzile. When saponified with caustic potash it 
 is resolved into benzoic acid and benzoin (B. 24, 1264). 
 
 Diehloro-stilbene, tolane dichloride C 6 H 5 CC1 : CC1.C 6 H 5 , exists in 
 two modifications : a-, m.p. 143 ; j8-, m.p. 63. Both are formed 
 by the addition of chlorine to tolane, or by the reduction of tolane 
 tetrachloride with iron and acetic acid, as well as from chloro-stilbene 
 
620 ORGANIC CHEMISTRY 
 
 dichloride (see above) with caustic potash. Chloro-bromo-stilbene 
 CgHgCCl : CBrC 6 H 5 , m.p. 174, is similarly prepared from chloro- 
 stilbene dibromide. Dibromo-stilbenes, a- melting at 208, and j8- melting 
 at 64, are obtained from tolane and bromine. Concerning p 2 -dioxy- 
 derivatives of dichloro-stilbene, and their conversion into the 
 methylene-quinones of the dibenzyl series, see /. pr. Ch. 2, 59, 228 ; 
 A. 325, 67. 
 
 CARBOXYLIC ACIDS OF THE DIBENZYL GROUP. These consist 
 of : (a) those in which the carboxyl group is in the benzene nucleus ; 
 (b) such as have the carboxyl group in the side chain : diphenylated 
 fatty acids. 
 
 The first group is composed chiefly of a series of o-carboxylic acids 
 produced by phthalic anhydride condensations : 
 
 Dibenzyi-o, o'- and -p, p'-dicarboxylie acid CO 2 HC 6 H 4 CH 2 . 
 CH 2 C 6 H 4 CO 2 H, m.p. 231 and over 320, are formed by the oxidation 
 of o- and p-toluic acid with potassium persulphate (B. 37, 3215). 
 
 o-Desoxy-benzom-carboxylicacidC 6 H 5 .CH 2 .CO.C 6 H 4 .COOH(+H 2 O), 
 melting at 75, is formed when boiling alkalies act on the corresponding 
 
 lactone. Benzylidene-phthalide, benzal-phthalide C 6 H 4 .CH : <ic 6 H 4 COC), 
 melting at 99, which results from the condensation of phthalic 
 anhydride and phenyl-acetic acid with the elimination of CO 2 . 
 
 By means of nitro-benzal-phthalide, benzal-phthalide can be changed 
 
 to iso- benzal-phthalide C 6 H 5 C : CH.C 6 H 4 .COO, melting at 91, the 
 anhydride of /?, o-desoxy-benzoin-earboxylic acid C 6 H 5 .CO.CH 2 .C 6 H 4 . 
 CO 2 H, melting at 163. The latter is made by decomposing /?-phenyl- 
 hydrindone with caustic soda, and from homo-phthalic anhydride with 
 benzene and A1C1 3 (B. 31, 377). Benzal-phthalide sustains a different 
 rearrangement under the influence of sodium alcoholate ; the sodium 
 salt of j3-phenyl-diketo-hydrindene is then produced : 
 
 C 6 H 5 .C : CH.C 6 H 4 .COO < C 6 H 5 CH : C.C 6 H 4 .COO > C 6 H 4 CH.CO.C 6 H 4 .CC)6 
 
 Iso-benzal-phthalide Benzal-phthalide Phenyl-diketohydrindene. 
 
 Hydrazin converts benzal-phthalide into benzyl - phthalazone 
 
 N NH 
 
 II I . By reduction with glacial acetic acid and zinc it 
 
 C 6 H 6 .CH 2 .C.C 6 H 4 .60 
 
 passes into benzyl-phthalimidine C 6 H 5 CH 2 .iHC 6 H 4 .CO.NH, melting at 
 137. It can also be obtained by the reduction of benzal-phthalimidine 
 (B. 29, 1434, 2743). Homologues of benzal-phthalide, see B. 32, 
 1104, etc. 
 
 o, o-Desoxy-benzoin-dicarboxylic acid COOH.C 6 H 4 .CH 2 .Cq.C 6 H 4 . 
 COOH, melting at 239, is obtained upon heating monophthalic acid 
 and sodium acetate (B. 24, 2820). The reduction of desoxy-benzom- 
 mono- and dicarboxylic acids yields dibenzyl-mono- and dicarboxylie 
 acids, melting at 131 and- 225. The oxidation of o-desoxy-benzoin- 
 carboxylic acid produces o-benzile-carboxylic acid C 6 H 5 .CO.CO.C 6 H 4 . 
 COOH, occurring in two modifications, one yellow in colour, melting 
 at 141, and another white, melting at i25-i3o (B. 23, 1344, 2079 ; 
 29, 2745 ; C. 1898, II. 481). 
 
 o, o-Benzile-diearboxylie acid, diphthalylic acid (COOHC 6 H 4 CO) 2 or 
 
CARBOXYLIC ACIDS OF THE DIBENZYL GROUP 621 
 
 6COC 6 H 4 C(OH).C(OH)C 6 H 4 CO6, m.p. 273, gives with acetyl chloride 
 a diacetyl derivative ; the acid esters are colourless, like the acid itself, 
 while the neutral esters are yellow. Diphthalide acid is formed by the 
 oxidation of chryso-quinone and chryso-ketone (A. 311, 264). The acid 
 is formed from phthalic anhydride with zinc dust and acetic acid and 
 
 subsequent oxidation, or by the oxidation of diphthalyl O.OC.C 6 H 4 C : 
 
 CC 6 H 4 COO, melting at 334. This latter body has been produced by 
 the condensation of phthalide and phthalic anhydride with potassium 
 cyanide (see formation of benzoin, p. 615) . Tetramethoxy-diphthalyl 
 
 6.0C.C 6 H 2 (OCH 3 ) 2 C:CC 6 H 2 (OCH 3 )COO (B. 24, R. 820; cp. B. 26, 
 540) is similarly made by the condensation of opianic ester. 
 
 Tetramethoxy-diphthalyl OOCC 6 H 2 (OCH 3 ) 2 C : CC 6 H 2 (OCH 3 ) 2 COO 
 (B. 24, R. 820 ; 26, 540). 
 
 Dithio-diphthalyl SCO.C 6 H 4 C : CC 6 H 4 COS, yellow-green needles, 
 m.p. 333, see B. 31, 2646. 
 
 Dihydro-diphthalyl-di-imide NH.CO.C 6 H 4 .CH.CHC 6 H 4 CO.NH, melt- 
 ing with decomposition at 284, results from the condensation of two 
 molecules of phthalic anhydride with methyl-alcoholic ammonia. This 
 substance is isomeric with indigo white (cp. B. 29, 2745). 
 
 Hydro-diphthalyl-lactonie acid HOOCCeH 4 CH 2 .CHC 6 H 4 COO, m.p. 
 198, is formed on heating homo-phthalic acid to 230 (B. 31, 376). 
 
 Dibenzyl-earboxylic acid a-phenyl-hydro-cinnamic acid, a, jS- 
 diphenyl-propionic acid, benzyl-pheny I- acetic acid C 6 H 5 CH 2 CH(C 6 H 5 ) 
 COOH, appears in three physical isomerides, melting at 95, 89, 82, 
 boiling at 335 (B. 25, 2017) . Its nitrile results upon introducing benzyl 
 into benzyl cyanide. a-Phenyl-o-amido-hydro-cinnamic acid, melting 
 at 148, is obtained in the reduction of a-phenyl-o-nitro-cinnamic acid 
 (B. 28, R. 391). It changes very readily into its lactame B-phenyl- 
 
 /CH 2 CH(C 6 H 5 )CO 
 kydrocarbo-styrile C 6 H 4 <^ , melting at 174. 
 
 a/3-Diphenyl-valerie acid C 2 H 5 CH(C 6 H 5 )CH(C 6 H 5 )COOH, m.p. 178 ; 
 its nitrile, m.p. 115, is formed by attaching C 2 H 5 MgI to a-phenyl- 
 cinnamic acid nitrile (C. 1906, II. 46). 
 
 Stilbene-earboxylic acid, a-phenyl-cinnamic acid C 6 H 5 CH : C(C 6 H 5 ) 
 C0 2 H, melting at 172, is formed in the condensation of benzaldehyde 
 with phenyl-acetic acid. Allo-phenyl-cinnamic acid, m.p. 137 (C. 1897, 
 II. 663) is also formed ; also stilbene on heating and expulsion of CO 2 
 (/. pr. Ch. 2, 61, i). a-Phenyl-cinnamic nitrite, m.p. 86, from benzyl 
 cyanide, benzaldehyde, and sodium ethylate. By reduction it becomes 
 a-phenyl-hydro-cinnamic acid, but does not add bromine. The action 
 of bromine upon the sodium salt produces bromo-stilbene (B. 26, 659). 
 a-Phenyl-o-amido-einnamic acid, m.p. 186, the reduction product 
 of o-nitro-a-phenyl-cinnamic acid, obtained in the condensation of 
 o-nitro-benzaldehyde with phenyl-acetic acid, yields j8-phenanthrene- 
 carboxylic acid (q.v.) (B. 29, 496) when its diazo-derivative is shaken 
 with copper in powder form. The nitrile of phenyl-o-amido-cinnamic 
 
622 ORGANIC CHEMISTRY 
 
 acid is easily transposed into a-amido-j8-phenyl-quinolin, so that syn- 
 thesis gives the latter instead of the nitrile (B. 32, 3399). The lactone 
 of phenyl-o-oxy-cinnamic acid, a-phenyl-cumarin C 6 H 4 /^^ H : ^ 6Hs , 
 
 m.p. 140, is formed from salicyl-aldehyde and phenyl-acetic acid (/. 
 pr. Ch. 2, 61, 178). o-, m-, and p-Oxy-benzal-benzyl cyanide HOC 6 H 4 
 CH : C(CN)C 6 H 5 , m.p. 104, 107, and 192 (B. 37, 3163). 
 
 a-Stilbene-methyl-ketone, 3, ^-diphenyl-butenone-2 C 6 H 5 CH : C(C 6 H 5 ) 
 COCH 3 , m.p. 51, from benzaldehyde and phenyl- acetone with 
 gaseous HC1. It does not add bromine, but gives on reduction with 
 sodium amalgam 3, 4-diphenyl-butanone C 6 H 5 CH 2 .CH(C 6 H 5 )COCH 3 , 
 b.p. 310 (M. 22, 659). 
 
 Stilbene - propionic acid, y, %-diphenyl-alyl-acetic acid C 6 H 5 CH : 
 C(C 6 H 5 ).CH 2 .CH 2 COOH, m.p. 106, from sodium-a-phenyl-glutarate 
 with benzaldehyde and acetic anhydride (B. 34, 4177). 
 
 Desyl-acetic acid, fifi-phenyl-benzoyl-propionic acid C 6 H 5 .COCH 
 (C 6 H 5 ).CH 2 .COOH, m.p. 161, is obtained as ester from the interaction 
 of sodium desoxy-benzoin and bromacetic ester (A. 319, 164) ; it is 
 also formed from phenyl-succinic-j8-methyl ester acid chloride with 
 benzene and A1C1 3 . By treatment with acetic anhydride sulphuric 
 acid in the cold the acid gives unstable diphenyl-A 2 -eroto-laetone 
 
 C 6 H 5 C : C(C 6 H 5 )CH 2 COO, m.p. 100, which, on boiling with acetic an- 
 hydride or treatment with alkalies, passes into the stable diphenyl- 
 
 A^croto-laetone C 6 H 5 CH.C(C 6 H 5 ) : CHCOO, m.p. 152. Both lactones, 
 treated with alkalies, regenerate desyl-acetic acid ; by the action of 
 permanganate or bromine the stable diphenyl-croto-lactone gives 
 desylene-acetic acid C 6 H 5 CO.C(C 6 H 5 ) : CHCOOH, m.p. 139, which 
 has also been obtained from desylene-malonic ester, the condensation 
 product of benzile withmalonic ester (A. 319, 155). Desyl-acetic acid 
 and the stable diphenyl-croto-lactone are also formed from diphenyl- 
 a-keto-butyro-lactone (i), the condensation product of phenyl-pyro- 
 racemic acid and benzaldehyde, which, on reduction, first yields an 
 oxy-lactone (2), and from the latter, by rejection of water, diphenyl- 
 croto-lactone (3) (B. 31, 2218 ; 36, 2344 ; A. 333, 160). 
 
 ( J ) (2) (3) 
 
 C 6 H 5 CH.CH(C 6 H 5 )\ CO _^ C 6 H 5 CH.CH(C 6 H 5 )\ CHQH ^ C C H 5 CH.C(C 6 H 5 )\ CH 
 6 CO/ 6 CO/ O CO/ 
 
 Dibenzyl - diearboxylie acid, sym. diphenyl - suceinic acid 
 
 C 6 H 5 .CH.COOH 
 
 occurs similarly to the dialkvl-succinic acids in 
 C 6 H 5 .CH.COOH 
 
 two isomeric forms. The a-acid (+H 2 O) is produced on heating 
 phenyl-bromacetic acid (2 mols.) with alcoholic CNK, also (together 
 with the jS-acid, m.p. 229) from stilbene-dicarboxylic acid with sodium 
 amalgam. The acid, containing one molecule of water, melts at 185 
 when rapidly heated ; it loses water and remelts at 220. When heated 
 to 200 with hydrochloric acid it changes to the j8-acid. Its anhydride, 
 melting at 116, is readily produced by means of acetyl chloride. 
 
 The j8-acid yields an anhydride (but with more difficulty) when heated 
 with acetyl chloride (B. 23, 117, R. 574 ; A. 259, 61). It melts at 112. 
 
 The nitrites C 6 H 5 CH(CN)CH(CN)C 6 H 5 , the a- melting at 160 and 
 
CARBOXYLIC ACIDS OF THE DIBENZYL GROUP 623 
 
 the j8- melting at 240, result from the condensation of phenyl-aceto- 
 nitrile with mandelo-nitrile by means of potassium cyanide (B. 25, 
 289 ; 26, 60). Both nitriles yield the jS-acid when they are saponified. 
 
 a, p - Diphenyl - glutaric acid C 6 H 5 CH(CO 2 H)CH(C 6 H 5 )CH 2 CO 2 H, 
 m.p. 231 ; its ester is obtained by attaching phenyl-acetic ester to 
 cinnamic acid ester by means of sodium ethylate (B. 42, 4497 ; C. 1908, 
 
 I. 1776). 
 
 J8, y-Diphenyl-adipic acid CO 2 HCH 2 CH(C 6 H 5 )CH(C 6 H 5 )CH 2 CO 2 H, 
 two modifications, m.p. 270 and 170. Dimethyl esters, m.p. 175 
 and 73, are formed by the reduction of cinnamic acid ester with Al 
 amalgam, together with nydro-cinnamic acid ester. The great simi- 
 larity to truxillic acid is noteworthy (A. 348, 16 ; B. 39, 4089). 
 
 Stilbene-dicarboxylic acid, diphenyl-malele acid, decomposes im- 
 mediately when separated from its salts, like the dialkylic maleic acids, 
 
 C 6 H 5 .C.C(\ 
 into water and its anhydride \\ ">O, m.p. 155. The latter 
 
 C 6 H 5 .C.CO 
 condenses, like phthalic anhydride, with phenyl-acetic acid and quickly 
 
 CTT f* f^- ,/-*TT f^ TT 
 g.LljjV^ V^ : ^Xi.Vx^JTLe 
 
 changes to benzal-diphenyl-maleide , which behaves 
 
 C 6 H 5 C CO/ 
 
 just like benzal-phthalide (B. 24, 3854). The salts of diphenyl- 
 maleic acid are formed when dicyano-stilbene C 6 H 5 C(CN) : C(CN)C 6 H 5 , 
 m.p. 158, are saponified with alcoholic potash. This nitrile is pro- 
 duced when phenyl-chloraceto-nitrile is treated with CNK or NaOC 2 H 3 , 
 or by the action of sodium alcoholate and iodine upon phenyl-aceto- 
 nitrile (B. 25, 285, 1680). 
 
 Stilbene-succinic acid, y-benzylidene-y-phenyl-pyro-tartaric acid, from 
 benzoin with succinic ester and sodium alcoholate. With Br the acid 
 gives a bromo-lactonic acid, which on heating yields an unsaturated 
 
 lactonic acid C 6 H 5 CH.C(C 6 H 5 ) : C(COO)CH 2 COOH and a dilactone 
 C 6 H 5 CH.C(C 6 H 5 ).CH(COO)CH 2 COO (A. 308, 156). 
 
 4, 5-Diphenyl-octane-2, 7 - dione, ajS - diacetonyl-dibenzyl 
 C 6 H 5 .CH.CH 2 .CO.CH 3 
 
 r J. W r W rnm ' m ' P ' l6l and b ' P ' 335-340, may be regarded 
 
 L 6 H 3 .CH.Cii 2 .CU.CJtl3 
 
 as a derivative of dibenzyl. It might be designated aj8- diacetonyl- 
 dibenzyl It results in the reduction of two molecules of benzyl- 
 idene-acetone in feebly acid or neutral solution (B. 29, 380, 2121). 
 Homologous diketones are formed from homologous benzylidene- 
 ketones by reduction (B. 35, 966). 
 
 C. Tri-, Tetra-, Penta-, and Hexaphenyl-ethane Group. Triphenyl- 
 ethane (C 6 H 5 ) 2 CHCH 2 C 6 H 5 , b.p. 348 (B. 37, 1455), by reduction 
 of triphenyl-ethylene, a-phenyl-stilbene (C 6 H 5 ) 2 C : CHC 6 H 5 , m.p. 68, 
 b.p. 221 ; also by extracting water from benzyl-diphenyl-carbinol 
 (B. 37, 1429, 1455). 
 
 Triphenyl-ethanone, or triphenyi-vinyl alcohol (C 6 H 5 ) 2 .CH.CO.C 6 H 5 
 or (C 6 H 5 ) 2 .C : C(OH)C 6 H 5 , m.p. 136, results from the action of benzene 
 and aluminium chloride upon chloral, upon dichloro- or trichoro-acetyl 
 chloride (B. 29, R. 292 ; A. 296, 219 ; 368, 92) ; also from triphenyl- 
 ethylene-glycol (C 6 H 5 ) 2 C(OH)CH(OH)C 6 H 5 , m.p. 164, the product of 
 the action of C 6 H 5 MgBr upon benzoin or mandelic ester (B. 37, 2762), 
 
624 ORGANIC CHEMISTRY 
 
 on heating with 25 per cent. H 2 SO 4 (C. 1908, I. 830). Potassium 
 permanganate oxidises it to benzo-phenone and benzoic acid, while 
 alcoholic potash resolves it into diphenyl-methane and benzoic acid. 
 With hydroxylamine chlorohydrate it yields an oxime, m.p. 182 (C. 
 1906, II. 1061). With acetyl chloride and benzoyl chloride we obtain 
 triphenyl- vinyl acetate and benzoate derivatives of the alcohol form. 
 
 Bromine in carbon disulphide converts it into triphenyl-brom- 
 ethanone (C 6 H 5 ) 2 CBrCOC 6 H 5 , m.p. 97, in glacial acetic acid; however, 
 by replacement of bromine with hydroxyl triphenyl-oxy-ethanone, 
 phenyl-benzo'in (C 6 H 5 ) 2 C(OH)COC 6 H 5 , m.p. 84, results. This is also 
 obtained by the oxidation of diphenyl-ethanone with HNO 3 , and from 
 benzile with CgH 5 MgBr (B. 32, 650 ; 37, 2758). Reduction of triphenyl- 
 ethanone or its bromination product gives triphenyl-ethanol, benzo- 
 hydryl-, phenyl-, carbinol (C 6 H 5 ) 2 CH.CH(OH)C 6 H 5 , m.p. 87, isomeric 
 with benzyl-, diphenyl-carbinol (see above) (C. 1897, II. 66 1). 
 
 Triphenyl - methyl - ethane, a, a, fi-triphenyl-propane (C 6 H 5 ) 2 CH. 
 CH(CH 3 )C 6 H 5 , is probably the product obtained by the reduction of 
 diphenyl-indone with phosphorus and hydriodic acid. Diphenyl- 
 indone is an intermediate product in the condensation of benzo- 
 phenone chloride with phenyl-acetic ester, whereby there results 
 
 Triphenyl-aerylie ester (CgH 5 ) 2 C : C(C 6 H 5 )COOR. The acid, melting 
 at 213, corresponding to this ester is obtained from its nitrite, melting 
 at 163, the condensation product of benzo-phenone chloride and benzyl 
 cyanide (B. 28, 1784 ; 29, 2841) The acid is also obtained from 
 triphenyl -propionie acid (C 6 H 5 ) 2 CH.CH(C 6 H 5 )CO 2 H, m.p. 211, the 
 product of attachment of C 6 H 5 MgBr to a-phenyl-cinnamic ester, by 
 bromination and rejection of HBr (C. 1905, I. 824 ; B. 34, 1963). 
 When diphenyl-indone is fused with caustic potash it yields an acid, 
 melting at 186, which is isomeric with triphenyl-acrylic acid. It is 
 probably 
 
 a,^-Diphenyl-vinyl-o-benzoicacidCOOH[2]C 6 H 4 C(C 6 H 5 ) : CH.C 6 H 5 . 
 Both acids, when heated with ZnCl 2 , revert again to diphenyl-indone 
 (B. 30, 1282). 
 
 Tetra-phenyl-ethane (C 6 H 5 ) 2 CH.CH(C 6 H 5 ) 2 , melting at 209 and 
 boiling at 37o-383, is formed when benzo-phenone or benzo-hydrol 
 chloride (C 6 H 5 ) 2 CHC1 is heated with zinc, and thio-benzo-phenone with 
 copper ; further, by the reduction of tetraphenyl-ethylene with sodium 
 and alcohol, of benzo-pinacone or benzo-pinacolin (see below) with 
 hydriodic acid and phosphorus, as well as by the condensation of 
 stilbene bromide, of tetrabromo-ethane, or of chloral with benzene and 
 A1C1 3 (B. 18, 657 ; 26, 1952 ; A. 296, 221). 
 
 Unsym. tetraphenyl - ethane (C 6 H 5 ) 3 C.CH 2 C 6 H 5 , m.p. 144, is 
 formed by the action of C 6 H 5 CH 2 MgCl upon triphenyl-chloro-methane, 
 or of (C 6 H 5 ) 3 CMgCl or (C 6 H 5 ) 3 CK upon benzyl chloride (B. 41, 435). 
 
 Tetraphenyl-ethylene (C 6 H 5 ) 2 C : C(C 6 H 5 ) 2 , melting at 221, is 
 formed, together with tetraphenyl-ethane, from benzo-phenone, and is 
 also obtained on heating benzo-phenone chloride with silver or with 
 zinc dust, together with the benzo-pinacolins (B. 29, 1789), also by 
 heating benzo-phenone chloride with diphenyl-methane (B. 43, 2958). 
 By oxidation it is split up into two molecules of benzo-phenone. It 
 unites with chlorine in CC1 4 solution to form tetraphenyl-ethylene 
 diehloride (C 6 H 5 ) 2 CC1.CC1.(C 6 H 6 ) 2 , m.p. 186, which is also obtained 
 
PHENYL-ETHANE GROUP 625 
 
 from benzo-phenone chloride by the action of molecular silver or mercury 
 as well as sodium iodide in acetone solution. With two molecules of 
 CHC1 3 or CC1 4 it gives crystalline addition products. Two chlorine 
 atoms in the tetraphenyl-ethylene dichloride are very loosely bound. 
 On heating alone it splits up into tetraphenyl-ethylene and chlorine, 
 the latter partly acting as a substituent. Upon boiling with water we 
 obtain a-benzo-pinacolin ; with methyl alcohol, j8-benzo-pinacolin. 
 The action of A1C1 3 upon the benzene solution brings about rejection of 
 2HC1 and formation of 9, lo-diphenyl-phenanthrene (B. 43, 1533, 2940). 
 Tetra - methyl - diamido - tetraphenyl - ethylene (CH 3 ) 2 NC 6 H 4 (C 6 H 5 )C : 
 C(C 6 H 5 )C 6 H 4 N(CH 3 ) 2 , m.p. 225, by reduction of dimethyl-amido- 
 benzo-phenone with tin and HC1. In acid solution with oxidising 
 agents like FeQ 3 it gives intensely red colorations (B. 39, 3765). 
 
 The alcohols of the tetraphenyl group are the pinacones of benzo- 
 phenone and its homologues. They are formed, like the pinacones 
 of the aliphatic series, from the ketones, together with secondary 
 alcohols, by the action of nascent hydrogen. 
 
 Benzo - pinacone, tetraphenyl - ethylene - glycol (C 6 H 5 ) 2 C(OH)C(OH) 
 (C 6 H 5 ) 2 , melts at 185 and splits into benzo-phenone and benzo-hydrol. 
 It sustains a like change when boiled with alcoholic potash. It is 
 formed from benzo-phenone by the action of zinc and sulphuric acid 
 or by the decomposition of sodium benzo-phenone (B. 25, R. 15), or by 
 condensation of oxalic methyl ester, or benzilic acid ester, with 
 C 6 H 5 MgBr (C. 1903, I. 967 ; B. 37, 2761). By heating with con- 
 centrated HC1 or dilute sulphuric acid to 200, benzo-pinacone, like 
 the ordinary pinacone (Vol. I.), passes with rejection of water and 
 migration of a phenyl group into the so-called jS-benzo-pmacolin 
 (C 6 H 5 ) 3 C.COC 6 H 5 , m.p. 170, which is also obtained synthetically by 
 the action of triphenyl-methyl-magnesium chloride upon benzaldehyde 
 and subsequent oxidation, as well as from triphenyl-acetyl chloride 
 and phenyl-magnesium bromide (B. 43, 1140) ; its constitution is 
 proved not only by these syntheses, but also by the splitting up into 
 triphenyl-methane and benzoic acid on heating with soda lime and by 
 the formation of triphenyl-carbinol and benzoic acid during oxidation. 
 j3-Benzo-pinacolin can also be obtained direct from benzo-phenone 
 with zinc dust and acetyl chloride besides the isomeric a-benzo- 
 pinacolin, m.p. 203, which is easily converted by acids into -benzo- 
 
 pinacolin and is probably tetraphenyl-ethylene oxide (C 6 H 5 ) 2 C.O.C(C 6 H 5 ) 2 
 (B. 29, 2158 ; 43, 1153). By heating with zinc ethyl j3-benzo-pinacolin 
 can be reduced to benzo-pinaeolm alcohol (C 6 H 5 ) 3 C.CH(OH)C 6 H 5 , 
 m.p. 151, which on heating with acetic anhydride passes into tetra- 
 phenyl-ethylene with return of the phenyl group (B. 23, R. 769) 
 (cp. the analogous formation of tetramethyl-ethylene from pinacolin 
 alcohol, Vol. I.). p 4 -Tetrachloro-benzo-pinacolin, see C. 1907, I. 475. 
 
 Pentaphenyl-ethane (C 6 H 5 ) 3 C.CH(C 6 H 5 ) 2 , m.p. 179, in CO 2 
 atmosphere, is formed by the transposition of diphenyl-methyl-mag- 
 nesium bromide (C 6 H 5 ) 2 CH.MgBr with triphenyl-chloro-methane (B. 39, 
 1466), as well as the action of zinc upon a mixture of diphenyl-bromo- 
 methane and triphenyl-chloro-methane in acetic ester (B. 43, 2945). It 
 is not so stable as the entirely stable tetraphenyl-ethane, and in that 
 respect approaches the easily dissociated hexaphenyl-ethanes. On 
 
 VOL. II. 2 S 
 
626 ORGANIC CHEMISTRY 
 
 heating in the air it is decomposed with absorption of oxygen. By 
 boiling its solutions in anisol or benzoic acid ester it is split up into 
 triphenyl, methyl-, or hexaphenyl-ethane and sym. tetraphenyl- 
 ethane (B. 43, 354 1 )- 
 
 2(C 6 H 3 ) 3 C-CH(C 6 H 5 ) 2 - ~> [(C 6 H 6 ) 3 C-] 2 +[-CH(C 6 H 5 ) 2 ] 2 . 
 
 Similarly, it decomposes on heating with benzene and HC1, or by the 
 action of sulphuryl chloride (B. 40, 367 ; 43, 2945). 
 
 Pentaphenyl-ethyl alcohol (C 6 H 5 ) 3 C.C(OH)(C 6 H 5 ) 2 , m.p. 179, from 
 /3-benzo-pinacolin and C 6 H 5 MgBr (B. 43, 1145). 
 
 Hexaphenyl-ethane, m.p. about 95 : this exceedingly interesting 
 hydrocarbon was first obtained by Gomberg (1900, B. 33, 3150) by the 
 action of zinc upon benzene solution of triphenyl-chloro-methane 
 (see A. 372, 17). It is distinguished by its great reactivity, which 
 makes it appear as an unsaturated compound. In solution it greedily 
 absorbs atmospheric oxygen with the formation of a peroxide 
 [(C 6 H 5 ) 3 C] 2 O 2 , m.p. 185, which on treatment with concentrated 
 sulphuric acid gives triphenyl-carbinol. Iodine solution is also 
 instantly decolourised with formation of triphenyl-iodo-methane 
 (B. 35, 1824). With benzene, ether, acetic ester, etc., hexaphenyl- 
 ethane forms crystal compounds which are easily dissociated (B. 38, 
 I 333 2 447)- Colourless in the solid state, hexaphenyl-ethane has a 
 yellow colour when dissolved. This colour, on shaking with air, 
 disappears with a precipitation of the peroxide mentioned, but the 
 colour reappears in a short time. The substance therefore exists in 
 solution in a colourless and a yellow modification, in a state of equili- 
 brium dependent upon the solvent and the temperature. Only the 
 coloured modification shows characteristic unsaturated behaviour of 
 hexaphenyl-ethane (Schmidlin, B. 41, 2471). It is assumed that by 
 the binding of the six unsaturated phenyl groups the affinities of the 
 ethane-carbon atoms are so much engaged that the affinities required 
 for binding these two carbon atoms do not suffice for a solid and 
 normal binding, and that therefore the hexaphenyl-ethane passes in 
 solution partly into the yellow unsaturated, and therefore very reactive 
 free radicle, triphenyl-methyl : 
 
 (C 6 H 5 ) 3 C-C(C 6 H 5 ) 3 nz^ 2(C 6 H 5 ) 3 C-. 
 
 Triphenyl-methyl is therefore the first example of a compound in 
 which one carbon atom only binds three univalent atomic groups, and 
 in which, therefore, carbon appears as a trivalent element. Hexa- 
 phenyl-ethane therefore shows a behaviour parallel with that of 
 nitrogen tetroxide, which, while colourless at low temperatures, de- 
 composes on heating into the coloured and very reactive hemimeric 
 nitrogen dioxide. From this point of view it is remarkable that the 
 organic radicle (C 6 H 5 ) 3 C unites with the inorganic radicles NO and NO 2 
 to form a colourless triphenyl-nitroso-methane (C 6 H 5 ) 3 C.NO and 
 triphenyl-nitro-methane (C 6 H 5 ) 3 C.NO 2 , m.p. 147, which, on heating, 
 easily decompose into their components (B. 44, 1169). 
 
 The action of concentrated HC1 converts hexaphenyl-ethane and 
 triphenyl - methyl into p - diphenyl - methyl - tetraphenyl - methane 
 (C 6 H 5 ) 2 CHC 6 H 4 C(C 6 H 5 ) 3 (B. 37, 4790). 
 
PHENYL-ETHANE GROUP 627 
 
 Besides the methods indicated, the following have also been used 
 for preparing hexaphenyl-ethane : (i) from triphenyl-methyl-mag- 
 nesium chloride and triphenyl-chloro-methane (B. 41, 423) ; (2) by 
 electrolysis of triphenyl-bromo-methane in SO 2 solution (A. 372, n) ; 
 (3) from hydrazo-triphenyl-methane (C 6 H 5 ) 3 C.NH.NH.C(C 6 H 5 ) 3 by 
 oxidation with potassium hypo-bromite by way of the unstable azo- 
 compound (B. 42, 3020). 
 
 While solid hexaphenyl-ethane does not pass into triphenyl-methyl, 
 and even its solution does so only in small quantities (see B. 37, 2041 ; 
 42, 3028), the tribiphenyl-methyl (C 6 H 5 .C 6 H 4 ) 3 C, obtained by withdrawal 
 of halogen from tribiphenyl-chloro-methane by means of powdered 
 copper, which is dark violet even in the solid condition, only exists 
 in solution in the form of the free radicle, as indicated by the molecular 
 weight. In contrast with these, a hydrocarbon obtained from the 
 
 similarly built biphenylene-biphenyl-chloro-methane ? 6 2 4 \xi(C 6 H 4 c 6 H 5 ) 
 
 ^e-"*' 
 
 is colourless even in solution and incapable of uniting with- oxygen or 
 halogen. It must therefore be regarded as undissociated dibiphenyl- 
 
 ene-dibiphenyl-ethane C * H *\C - c < 6 2 4 - Between these two 
 
 6 4 
 
 extremes the similarly obtained hydrocarbons, diphenylene-diphenyl- 
 ethane, tetraphenyl-dibiphenyl-ethane, and diphenyl-tetrabiphenyl- 
 ethane occupy a middle position, decomposing in solution with more 
 or less ease into the hemimeric triaryl-methyls (Schlenk, A. 372, I ; 
 B. 43, 1753)- 
 
 Tetraphenyl - ethane - diearboxylie acid, tetraphenyl - succinic acid 
 
 //-> TT \ /-> (~ > r - \/"\TiJ' 
 
 ' V , melting at 261 with decomposition (its ethyl ester at 89), 
 
 (L/gtlg) 2 (-'.v-/O(J.ri. 
 
 is obtained from diphenyl-chloracetic ester by the action of silver 
 (B. 22, 1538). Its nitrite, melting at 215, is formed by the interaction 
 of the nitrile of diphenyl-acetic acid with sodium and iodine. 
 
 The dilactone of a benzo-pinacone-o 2 -dicarboxylic acid O.CO.C 6 H 4 C 
 
 (C 6 H 5 ).C(C 6 H 5 )C 6 H 4 COO, melting at 265, is formed on boiling o-benzoyl- 
 benzoic acid with hydriodic acid and phosphorus (B. 29, R. 498). 
 
 D. co, aj-Diphenyt-propane Group. Dibenzyl-methane, a, y-diphenyl- 
 propane C 6 H 5 .CH 2 .CH 2 .CH 2 .C 6 H 5 , boiling at 29O-3OO, results by the 
 reducing action of hydriodic acid upon dibenzyl-ketone (see below). 
 
 a, y-Diphenyl-propylene C 6 H 5 CH 2 .CH : CHC 6 H 5 , b.p. 15 179, an 
 oil with an odour of hyacinth, is formed from a, y-diphenyl-propyl 
 alcohol, b.p. 12 193, with anhydrous oxalic acid ; also from j8-bromo- 
 dibenzyl-acetic acid by heating with dilute soda solution (B. 39, 3046). 
 
 Tetraphenyl-allene (C 6 H 5 ) 2 C : C : C(C 6 H 5 ) 2 (?), m.p. 164, from the 
 dry distillation of barium-diphenyl acetate (B. 39, 1024). 
 
 " Dibenzyl-ketone C 6 H 5 .CH 2 .CO.CH 2 .C 6 H 5 , melting at 40 and boiling 
 at 330 (B. 24, R. 946). This body is produced in the distillation of 
 calcium-phenyl-acetate. One hydrogen atom of each of the two 
 CH 2 groups can be replaced by alkyls. It condenses with oxalic ester 
 and sodium ethylate to a triketo-R-pentene derivative, oxalyl-dibenzyl- 
 ketone. With benzal-aniline it yields an addition product which takes 
 various forms (C. 1899, II. 664). With PC1 5 it yields 1, 3-diphenyl-2- 
 ehloro-propylene C 6 H 5 CH 2 .CC1 : CHC 6 H 5 , b.p. 12 181, and di-iso- 
 
628 ORGANIC CHEMISTRY 
 
 nitroso-dibenzyl-ketone C 6 H 5 C(NOH).COC(NOH)C 6 H 5 , with nitrous 
 acid, m.p. 133 (B. 37, 1134). 
 
 Sodium reduces dibenzyl-ketone to dibenzyl-earbinol (C 6 H 5 .CH 2 ) 2 
 CH.OH, boiling at 327. It combines to dibenzyl-diphenol-methane 
 (C 6 H 5 CH 2 ) 2 C(C 6 H 4 OH) 2 (B. 25, 1271) with phenol. 
 
 Dibenzyl-phenyl-earbinol (C 6 H 5 CH 2 ) 2 C(OH)C 6 H 5 , m.p. 87, and 
 tribenzyl-earbinol (C 6 H 5 CH 2 ) 3 C(OH), m.p. 115, from benzoic acid ester 
 and phenyl-acetic ester with two molecules C 6 H 5 CH 2 MgCl (B. 37, 1456). 
 
 Benzyl-aeeto-phenone C 6 H 5 CH 2 .CH 2 .CO.C 6 H 5 , m.p. 73, is isomeric 
 with dibenzyl-ketone. It is produced on reducing benzylidene-aeeto- 
 phenone C 6 H 5 CH : CH.CO.C 6 H 5 , m.p. 58, b.p. 346, with zinc dust 
 and acetic acid. This latter compound is the condensation product 
 of benzaldehyde and aceto-phenone. By means of sodium methylate 
 it yields two stereo-isomeric oximes, m.p. 75 and 116, the latter of 
 which on Beckmann's transposition gives cinnamic anilide (A. 351, 172) . 
 With HC1 it unites to form chloro-benzyl-aeeto-phenone C 6 H 5 CHC1CH 2 
 COC 6 H 5 ; with bromine, a dibromide C 6 H 5 CHBr.CHBr.COC 6 H 5 , m.p. 
 157, which, with alcoholic potash, yields monobromo-benzylidene 
 aceto-phenone C 6 H 5 .CBr : CHCOC 6 H 5 , m.p. 44 (A. 308, 219). The 
 action of nitrous gases upon benzal-aceto-phenone gives various 
 products, of which we may mention the sub-nitride (C 15 H 12 O)N 2 O 4 , 
 which, on treatment with dilute soda, gives benzal-nitro-aeeto-phenone 
 C 6 H 5 CH : C(N0 2 )COC 6 H 5 , m.p. 90. The reduction of the latter with 
 stannous chloride and HC1 in methyl alcohol, produces benzyl-iso- 
 nitroso-aceto-phenone C 6 H 5 CH 2 .C(NOH).COC 6 H 5 , m.p. 126, an oxime 
 of the diphenyl-diketo-propane which is isomeric with dibenzoyl-methane 
 (B. 36, 3015 ; A. 340, 63). 
 
 p 2 -Diehloro-benzylidene-aeeto-phenone, m.p. 157, yields, with 
 PC1 5 in benzene solution, a keto-chloride C1C 6 H 4 CH : CH.CC1 2 C 6 H 4 C1, 
 m -P- 55> i n which one of the chlorine atoms occupies the middle 
 position, is exceedingly mobile, and can easily be replaced by hydroxyl 
 or methoxyl on treatment with moist silver oxide or methyl alcohol. 
 The compounds dissolve in concentrated sulphuric acid with intense 
 coloration (B. 42, 1804) (cp. also dibenzylidene-acetone) . 
 
 o-, m-, p-Oxy-benzylidene-aceto-phenone, from the corresponding 
 oxy-benzaldehydes and aceto-phenone, melt at 154 with decomposition, 
 at 160 and 183. 
 
 The isomeric benzylidene-o-, m-, and p-oxy-aceto-phenones, m.p. 
 89, 126, and 173 respectively, are formed from benzaldehyde and 
 the oxy-aceto-phenones. Coloration of the isomers, see B. 32, 1921. 
 Several poly-oxy-benz3>lidene-aceto-phenones are found in nature, 
 usually in the form of glucosides. 
 
 Butein (HO) 2 [3, 4]C 6 H 3 CH : CH.COC 6 H 3 [2', 4 / J(OH) 2 , orange-yellow 
 needles, m.p. 214, as a glucoside in the flowers of Butea frondosa ; 
 this is split up on boiling with potash into proto-catechuic acid and 
 resaceto-phenone (C. 1904, II. 451). Naringenin HO[4]C 6 H 4 CH : CH. 
 COC 6 H 2 [2 / , 4', 6'](OH) 3 , m.p. 248, and hesperitin (HO) [3] (CH 3 O) [4] 
 C 6 H 3 CH : CH.COC 6 H 2 [2', 4', 6'](OH) 3 , m.p. 224, are formed by break- 
 ing up the glucosides naringin and hesperidin (q.v.) with dilute acids, 
 On boiling with potash they yield phloro-glucin and p-cumaric acid 
 and iso-ferulic acid respectively. Isomers of hesperitin are homo-erio- 
 dictyol HO[4](CH 3 0)[3]C 6 H 3 CH : CH.COC 6 H 2 [ 2 ', 4', 6'](OH 3 ), b.p. 
 
CD, co-DIPHENYL-PROPANE GROUP 629 
 
 223, and eriodietyol (HO) 2 [3, 4]C 6 H 3 CH : CH.COC 6 H 2 [ 2 ', 4', 6^OH) 3 , 
 m.p. 267, from the leaves of Eriodictyon californicitm (C. 1911, I. 150). 
 On boiling with mineral acids the benzylidene-o-oxy-aceto-phenones 
 
 r /^\ _ PTT f* TT 
 
 are transformed into the isomeric flavanones c H *\ coCH ' 5 > a re ~ 
 
 action which has been used for the synthesis of numerous vegetable 
 dyes belonging to this group ; cp. quercetrin, fisetin, luteolin, etc. 
 Alcoholic potash converts acety-o-oxy-benzylidene-aceto-phenone 
 
 into benzoyl-cumarone (q.v.) C 6 H 4 <^ CH ^C.CO.C 6 H 5 . Reduction changes 
 
 o-oxy- benzylidene-aceto-phenone into a-phenyl-y-(o-oxy-phenyl)-propyl 
 alcohol HO.C 6 H 4 .CH 2 .CH 2 .CH(OH) C 6 H 5 , m.p. 97, which is con- 
 
 x 2 . 2 
 
 densed by HC1 in methyl alcohol to a-phenyl-cumaran C 6 H 4 < 
 
 ^O CH.CjHg 
 (B. 29,244,375). 
 
 o-Oxy-styryl-diphenyl-earbinol HO[2]C 6 H 4 CH : CHC(OH)(C 6 H 5 ) 2 , 
 m.p. i64-i66, from cumarin with two molecules C 6 H 6 MgBr (C. 1903, 
 I. 1179 ; B. 37, 496). 
 
 The condensation of two molecules of aceto-phenone by heat alone, 
 or by zinc ethide or zinc chloride, yields a homologue of benzal-aceto- 
 phenone called dypnone C 6 H 5 .C(CH 3 ) : CH.COC 6 H 5 , m.p. 225 (22 mm.), 
 which sustains the same relation to aceto-phenone as mesityl oxide 
 bears to acetone (B. 27, R. 339) ; heating splits up dypnone with 
 formation of unsaturated hydrocarbons, diphenyl-furfurane, and tri- 
 phenyl-benzol (C. 1899, II. 96). On standing in alcoholic solution, 
 dypnone combines with hydroxylamine to form dypnone-hydroxylamine 
 C 6 H 5 C(CH 3 )(NHOH).CH 2 COC 6 H 5 , m.p. 110 ; under other conditions 
 two dypnone oximes are formed, C 6 H 5 C(CH 3 ) : CHC(NOH)C 6 H 5 , m.p. 
 78 and 134, the latter of which yields by Beckmann's transposition 
 the anilide of j3-methyl-cinnamic acid (B. 37, 730). 
 
 Benzaldehyde condenses as readily as aceto-phenone with desoxy- 
 benzoin under the influence of alkalies, forming benzylidene-desoxy- 
 benzoln C 6 H 5 CH : C(C 6 H 5 )CO.C 6 H 5 , m.p. 101; this is also formed from 
 benzamarone by distillation, besides iso-benzylidene-desoxy- benzoin, 
 m.p. 89. The latter is easily converted into the isomeride of higher 
 melting-point. It is also formed by condensation of benzaldehyde 
 and desoxy-benzoin by means of HC1 and chloro-benzyl-desoxy- 
 benzoin, m.p. 172, which is easily converted by alkalies into benzal- 
 desoxy-benzoin, m.p. 101 ; but it is split up by distillation into stilbene 
 and benzoyl chloride (B. 26, 447, 818 ; 34, 3897 ; 35, 3865) : 
 
 C 6 H 5 CH _ C 6 H 5 CHC1 
 
 C 6 H 5 CCOC 6 H 6 * C G H 5 CHCOC 6 H 5 
 
 By reduction, benzal-desoxy-benzoin yields benzyl-desoxy-benzoin 
 C 6 H 5 fCH 2 .CH(C 6 H5)COC 6 H 5 , m.p. 120, which can also be obtained 
 direct by benzylating desoxy-benzoin. 
 
 )3j8-Diphenyl-propio-phenone C 6 H 5 COCH 2 .CH(C 6 H 5 ) 2 , m.p. 96, by 
 attachment of one molecule phenyl-magnesium bromide to benzal- 
 aceto-phenone (C. 1904, II. 445). Correspondingly, we obtain from 
 phenyl-magnesium bromide and benzylidene- desoxy-benzoin in ether 
 solution : 
 
 a, 0, ft - Triphenyl- propio - phenone C 6 H 5 COCH(C 6 H 5 )CH(C 6 H 5 ) 2 , 
 
630 ORGANIC CHEMISTRY 
 
 m.p. 182, which is also formed from a-phenyl-cinnamic ester with gases 
 of phenyl-magnesium bromide. In ligroin solution it is found possible to 
 isolate, as the first addition product, the tetraphenyl-propinol C 6 H 5 C(OH) : 
 C(C 6 H 5 )CH(C 6 H 5 ) 2 , which, at 95-ioo, melts with transformation into 
 triphenyl-propio-phenone. It greedily absorbs oxygen, with formation 
 of a peroxide, m.p. 127, which, on heating, decomposes into diphenyl- 
 aceto-phenone and benzoic acid (C. 1906, II. 1059). 
 
 Benzoyl - dibenzyl - methane, dibenzyl - aceto - phenone C 6 H 6 COCH 
 (CH 2 C 6 H 5 ) 2 , m.p. 78, is formed by heating aceto-phenone with benzyl 
 chloride and caustic potash to i6o-i70 (A. 310, 322). 
 
 By condensation of o-phthal-aldehydic acid with aceto-phenone we 
 
 /CHCH 2 COC 6 H 6 
 
 obtain phenacyl-phthalide C 6 H 4 <^ \ , m.p. 182 (C. 1898, II. 
 
 coo 
 
 980). 
 
 Benzoyl-phenyl-aeetylene C 6 H 5 COC : CC 6 H 5 , m.p. 50, from sodium- 
 phenyl-acetylene and benzoyl chloride in ether. This is split up by 
 alkalies into aceto-phenone and benzoic acid, and by concentrated 
 sulphuric acid into dibenzoyl-methane (A. 308, 276 ; C. 1900, I. 1290). 
 Phenyl-acetylene-phenyl-earbinol C 6 H 5 C ; C.CH(OH)C 6 H 6 , b.p. 221, 
 from sodium-phenyl-acetylene and benzaldehyde (C. 1902, I. 629). 
 
 Dibenzoyl-methane C 6 H 5 CO.CH 2 .COC 6 H 6 or C 6 H 5 C(OH) :CHCOC 6 H 5 
 (cp. Proc. Chem. Soc., 20, 48), m.p. 81, is formed by boiling 
 dibenzoyl-acetic ester with water, by condensation of benzoic acid 
 ester and aceto-phenone, or by transposition of the aceto-phenone-O- 
 benzoate C 6 H 5 C(OCOC 6 H 5 ) : CH 2 obtained from aceto-phenone by heat- 
 ing with benzoyl chloride, the transposition being effected by boiling 
 with sodium in benzene solution (B. 36, 3674). It is soluble in alkali, 
 forms a sparsely soluble copper salt and a red iron salt, and is easily 
 attacked by potassium permanganate. On treatment with benzoyl 
 chloride and pyridin it yields an 0-benzoate C 6 H 5 C(OCOC 6 H 5 ) : 
 CHCOC 6 H 5 , m.p. 109 (B. 36, 3679). Nitrous acid converts it into an 
 iso-nitro so-derivative (C 6 H 5 .CO) 2 C : N.OH, which may be converted into 
 the corresponding diphenyl-triketone C 6 H 5 .CO.CO.CO.C 6 H 5 , b.p. 289, 
 (175 mm. pressure). It solidifies to a golden-yellow mass, melting "at 
 70. It combines with water to a colourless hydrate (B. 23, 3378). 
 
 Dibenzoyl-aeetyl-methane, dibenzoyl-acetone, occurs in two forms, 
 one of which probably represents the diketo-hydroxyl form (C 6 H 5 .CO) 2 
 C : C(OH)CH 3 (a-, m.p. 80), the other the triketo form (C 6 H 5 CO) 2 .CH. 
 COCH 3 (/?-, m.p. i07-iio). It results from benzoyl-acetone and 
 benzoyl chloride with soda. Similarly, dibenzoyl-methane yields (jB)- 
 tribenzoyl-methane (C 6 H 5 CO) 3 CH, m.p. 225. By boiling with potash 
 and acetic ester this /^-modification is changed to the a-form(C 6 H 5 CO) 2 C : 
 C(OH)C 6 H 5 , soluble in alkalies (A. 291, 25). The latter combines with 
 one molecule diazo-benzol chloride to form a yellow diazo-oxy-com- 
 pound (i), m.p. 125, which is easily split up by mineral acids. On 
 heating, it first turns into the red C-azo-compound (2), m.p. 164, 
 stable in the presence of acids, and further, by migration of a benzoyl 
 group, into the colourless benzoyl- phenyl-hydrazone of diphenyl-tri- 
 ketone (3), m.p. 203 (B. 41, 4012) : 
 
 (C 6 H 5 CO) 2 :C (C 6 H 6 CO) 2 : C.N : NC 6 H 5 (C 6 H 5 CO) 2 : C : N.NC,H 5 
 
 (i) C 6 H 5 C.O.N:NC 6 H 5 (2) C 6 H 5 CO (3) C a H 6 CO 
 
co, co-DIPHENYL-PROPANE GROUP 631 
 
 This process corresponds to the transposition of fatty aromatic azo- 
 compounds into aryl-hydrazones, and to a reversal of the conversion 
 of the quinone-acyl-phenyl-hydrazones into O-acylated oxy-azo- 
 compounds. 
 
 Carboxy lie Acids. Dibenzyl-acetic acid (C 6 H 5 .CH 2 ) 2 CH.COOH, m.p. 
 87, is formed from a-benzyl-cinnamie acid C 6 H 5 CH : C(CH 2 C 6 H 5 ) 
 COOH, m.p. 159, the condensation product of benzaldehyde with hydro- 
 cinnamic acid by reduction with Na amalgam (/. pr. Ch. 2, 62, 545). 
 It is also derived from dibenzyl-malonic acid (C 6 H 5 CH 2 ) 2 C(COOH) 2 , the 
 ester of which is produced by benzylating malonic ester. 
 
 X^TT ^-*TT f^T-T 
 
 o, o-Dinitro-benzyl-acetic acid C 6 H,/ 2 ^>C 6 H 4 , made 
 
 \N0 2 COOH N0 2 / 
 
 in an analogous manner, may be condensed by reduction with zinc 
 dust to tetrahydro-naphthinolin (q.v.) (B. 27, 2248 ; 29, 636). 
 
 Dibenzoyl-malo-nitrile (C 6 H 5 CH 2 )C(CN) 2 , m.p. 130 and'b.p. 360, is 
 obtained from the corresponding nitrilo-acid amide, which is prepared 
 from cyanacetamide. Sodium and alcohol reduce the nitrile with 
 elimination of a cyanogen group to dibenzyl-ethylamine (C 6 H 5 CH 2 ) 2 CH. 
 CH 2 .NH 2 , whose hydrochloride melts at 190 (B. 29, R. mi). 
 
 Dibenzyl-glyeolic acid (C 6 H5.CH 2 ) 2 C(OH).CO 2 H, oxatolylie acid, is 
 produced by saponification of its nitrile, the HCN addition product of 
 dibenzyl-ketone, and when vulpic and pulvic acids are boiled with 
 dilute alkalies. It melts at 156. When boiled with concentrated 
 potassium hydroxide it decomposes into oxalic acid and two molecules 
 of toluol (A. 219,4i). 
 
 a-Phenyl-j8-benzoyl-propionic acid, phenyl-phenacyl-acetic acid, 
 C 6 H 5 CO.CH 2 .CH(C 6 H 5 )COOH, melts at 153. Its nitrile melts at 
 127. Its ester is formed from phenyl-succinic-a-methyl ester acid 
 chloride with benzene and A1C1 3 . The acid is produced when CNK acts 
 upon chloro-benzyl-aceto-phenone. If heated with acetic anhydride 
 it yields the lactone of isomeric a, y-diphenyl-y-oxy-erotonie acid 
 
 CeH 5 C : CH.CH(C 6 H 5 )COO, melting at 110, while upon reduction 
 with sodium amalgam, a, y - diphenyl - butyro - lactone C 6 H 5 . 
 
 CH.CH 2 .CH(C 6 H 5 )COO (A. 284, i). 
 
 a, y-Diphenyl-aceto-aeetie acid is isomeric with phenyl-phenacyl- 
 acetic acid. Its ester , C 6 H 5 .CH 2 .CO.CH(C 6 H 5 )CO 2 C 2 H 5 , melting at 79, 
 is formed when two molecules of phenyl-acetic ester are condensed with 
 sodium ethylate. Concentrated sulphuric acid condenses the ester to 
 a naphthalene derivative phenyl-naphtho-resorcinol (A. 296, I.) 
 
 0-Phenyl-y-benzoyl-butyrie acid C 6 H 5 CO.CH 2 .CH(C 6 H5).CH 2 .COOH, 
 m.p. 153, is formed by attachment of aceto-phenone to cinnamic ester, 
 by means of sodium ethylate, and by transformation of the addition 
 product of malonic ester and benzylidene-aceto-phenone (B. 34, 653). 
 
 Benzylidene-benzoyl-aeetic ester, m.p. 98, from benzaldehyde, 
 benzoyl-acetic ester, and piperidin (C. 1903, I. 1420 ; II. 1270). 
 
 Dibenzoyl-aeetic acid (C 6 H 5 .CO) 2 CH.COOH melts at 109. Its 
 ester, from benzoyl-acetic ester and benzoyl chloride, yields CO 2 and 
 dibenzyl-methane by dry distillation, and aceto-phenone, carbon 
 dioxide, and benzoic acid when digested with sulphuric acid. Its 
 nitrile, obtained from cyan-aceto-phenone with benzoyl chloride, shows 
 
632 ORGANIC CHEMISTRY 
 
 very acid properties. The silver salt gives, with methyl iodide and 
 methyl ether, C 6 H 5 COC(CN) : C(OCH 3 )C 6 H 5 , m.p. 118; with benzoyl- 
 chloride, tribenzoyl-aceto-nitrile (C 6 H 5 CO) 3 C.CN or C 6 H 5 COC(CN) : 
 C(OCOC 6 H 5 )C 6 H 5 , m.p. 138 (/. pr .Ch. 2, 58, 151). 
 
 y-Phenyl--benzylidene-a-keto-butyro-lactone c H ^ 6 H 5 <^_ co / co > 
 
 m.p. 167 ; this keto-lactone, in the form of yellow crystals, is obtained 
 by condensation of two molecules benzaldehyde with pyro-racemic 
 acid by means of gaseous HC1 (B. 32, 1450 ; 34, 817) ; on reduction 
 with sodium amalgam it gives y-phenyl-j3-benzyl-keto-butyro-lactone, 
 in two modifications, m.p. 134 and 137 (also from benzyl-pyro-racemic 
 acid with benzaldehyde). The isomeric jS-phenyl-y-benzyl-a-keto- 
 butyro-laetone, m.p. 171, is formed from two molecules phenyl-pyro- 
 racemic acid with rejection of CO 2 (B. 35, 1942). 
 
 f* M P"H" \ /POOTT 
 
 y-Benzyl-y-benzylidene-pyro-raeemie acid ^CH X CH \CH,COOH' 
 m.p. 147 ; its ester is formed by condensation of dibenzyl-ketone and 
 succinic ester by sodium alcoholate (A. 308, 175). 
 
 from succinic acid ester and benzal aceto-phenone by means of NaOC 2 H 5 ; 
 its dimethyl ester is easily further condensed to pentacyclic diketone- 
 
 carboxylic ester 6 * '** VTJ ^TJ which is in turn easily split 
 
 U 6 ri 5 L/rl ^JtlLAJ 2 ^H3 
 
 up by sodium methylate to an acyclic dimethyl ester (A. 326, 347). 
 
 a, j8, y-Triphenyl-glutaric acid C 6 H 5 CH[CH(C 6 C 5 )COOH] 2 , m.p. 237; 
 the nitrite, m.p. 138, of this acid is formed by the combination of benzal- 
 benzyl cyanide with the second molecule of benzyl cyanide (B. 31, 
 
 3059)- 
 
 E. co, ay-Diphenyl-butane Group. Dibenzyl-ethane, a, S-diphenyl- 
 butane C 6 H 5 .CH 2 .CH 2 .CH 2 .CH 2 .C 6 H 5 , melting at 52, is formed by the 
 reduction of A 2 -diphenyl-butylene C 6 H 6 .CH : CH.CH 2 .CH 2 .C 6 H 5 , which 
 is produced from diphenyl-butadiene and diphenyl-butenin with Na 
 amalgam (A. 342, 253), or from a-phenyl-cinnamenyl- aery lie acid nitrile 
 with Na and alcohol (B. 23, 2857). 
 
 a, 8-Diphenyl-butadiene, diphenyl-diethylene C 6 H 6 CH : CH.CH : 
 CHC 6 H 5 , is known in its three theoretically possible stereo-isomeric 
 forms : a-form (trans-trans), m.p. 151 ; j8-form (cis-cis), m.p. 70-5 ; 
 y-form (cis- trans), oily. Of these the a-form is most stable, and the 
 other forms pass into it on standing, and do so rapidly in sunlight. 
 The a-form is obtained (i) by heating a-phenyl-cinnamenyl-acrylic acid 
 or dibenzal-propionic acid ; (2) from the dibromide of A 2 -diphenyl- 
 butylene by means of quinolin ; (3) in small quantity on reduction of 
 phenyl-acetylene with zinc dust and alcohol ; (4) by the action of 
 magnesium upon co-bromo-styrol (B. 43, 1232). The jS-form is obtained 
 from diphenyl-diacetylene, the y-form from diphenyl-butenin (m.p. 97) 
 by reduction with zinc dust and alcohol (A. 342, 238). With bromine 
 in chloroform the diphenyl-butadiene gives dibromide, m.p. 141, 
 which is also obtained by attachment of two molecules HBr of diphenyl- 
 butenin, and probably contains the bromine atoms in the i, 4-position 
 (A. 342, 244). With two molecules NO 2 it also combines with i, 4- 
 addition to diphenyl-dinitro-butylene C 6 H 5 CH(NO 2 ).CH : CH.CH(NO 2 ) 
 C 6 H 5 , m.p. 158, colourless needles from which, by action of alkalies, 
 
a>, co-DIPHENYL-BUTANE GROUP 633 
 
 nitrous acid is split off to form diphenyl-a-nitro-butadiene C 6 H 5 C(NO 2 ) : 
 CH.CH : CHC 6 H 5 , m.p. 112, in golden-yellow columns (A. 360, 299). 
 
 Diphenyl-butenin C 6 H 5 CH : CH.C : CC 6 H 5 also occurs in two stereo- 
 isomeric forms, of which the stable trans-form, m.p. 97, is formed by 
 solution of phenyl-acetylene-copper in glacial acetic acid, and the 
 unstable liquid cis-form, b.p. 12 188, by partial reduction of diphenyl- 
 diacetylene with zinc dust and alcohol. Illumination or traces of . 
 iodine convert the unstable form into the stable form (A. 342, 225). 
 
 Diphenyl-diacetylene C 6 H 5 C ; C.C ; C.C 6 H 5 , melting at 88. This 
 is made by shaking copper phenyl-acetylide CgH^C ; C.Cu in am- 
 moniacal solution with air, or by the action of potassium ferricyanide. 
 It is the parent hydrocarbon of indigo-blue. Its o, o-dinitro- derivative 
 
 C 6 H 4 <^ ;, C '~ : 5fX 6 H 4 ( from o-nitro-phenyl-acetylene) is rearranged by 
 
 xJNvJo ^-^2 4. 
 
 concentrated sulphuric acid into the isomeric di-isatogen (q.v.), which 
 becomes indigo-blue : C e H 4 <>C : C <XW 4> by reduction with 
 
 ammonium sulphide (B. 15, 53). 
 
 The action of Br in CS 2 solution produces a dibromide, m.p. 42, and a 
 tetrabromide, m.p. 173, but bromination in ether or acetic acid solution 
 produces ring-closure and tribromo-phenyl-naphthalin (A. 342, 229). 
 
 a a, S-Triphenyl-butadiene (C 6 H 5 ) a C : CH.CH : CHC 6 H 5 , m.p. 102, 
 and a, a, p, S-tetraphenyl-butadiene (C 6 H 5 ) 2 C : C(C 6 H 5 ).CH : CHC 6 H 5 , 
 m.p. 147, are formed by attaching diphenyl-ketone to cinnamic alde- 
 hyde and benzal-aceto-phenone respectively, with rejection of CO 2 
 (B. 42,4249). 
 
 a, a, 3, 5 - Tetraphenyl - butadiene (C 6 H 5 ) 2 C : CH.CH.C : C(C 6 H 5 ) 2 , 
 m.p. 202, from tetraphenyl-tetramethylene-glycol (C 6 H 5 ) 2 C(OH).CH 2 . 
 CH 2 .C(OH)(C 6 H 5 ) 2 , m.p. 208, the condensation product of succinic 
 ester with phenyl-magnesium bromide (C. 1903, I. 967). 
 
 Ketones. Phenethyl-benzyl-ketone, i, ^-diphenyl-butanone C 6 H 5 . 
 CH 2 .CH 2 .CO.CH 2 .C 6 H 5 , boiling at 234-238, is produced when hydro- 
 cornicularic acid is distilled with lime ; also by distillation of calcium- 
 phenyl acetate and hydro-cinnamate. It is obtained pure by the 
 reduction of 1, 4-diphenyl-butenone, styryl-benzyl-ketone C 6 H 5 CH : 
 CHCOCH 2 C 6 H 5 , m.p. 71, formed from benzaldehyde and phenyl- 
 acetone by alkaline condensation (M. 22, 659, 749). 
 
 Phenyl-iso-erotone-phenone C 6 H 5 CO.CH 2 .CH : CHC 6 H 5 , m.p. 93, is 
 obtained by the reduction of diphenyl-a-nitro-butadiene with SnCl 2 and 
 HC1 ; it dissolves in alkalies with formation of salts of diphenyl-oxy- 
 butadiene C 6 H 5 C(OH) : CH.CH : CHC 6 H 5 ; with benzaldehyde, it con- 
 denses and forms dibenzal-propio-phenone C 6 H 5 COC( : CHC 6 H 5 ).CH : 
 CHC 6 H 5 , m.p. 117 (B. 40, 4825). o-Oxy-styryl-benzyl-ketone HO[i] 
 C 6 H 4 CH : CHCOCH 2 C 6 H 5 , b.p. 12 2i7-2i9, from cumarin with benzyl- 
 magnesium chloride (B. 37, 498). 
 
 Diphenaeyl, dibenzoyl-ethane C 6 H 5 CO.CH 2 .CH^.COC 6 H 5 , m.p. 145, 
 from phenacyl-benzoyl-acetic ester by ket one-splitting, and by reduc- 
 tion of dibenzoyl-ethylene and various halogen diphenacyls ; as a 
 y-diketone it easily forms diphenyl-furfurane, thiophene, and pyrrol. 
 
 y-Chloro- and y-bromo-diphenacyl C 6 H 5 COCHC1.CH 2 COC 6 H 5 and 
 C 6 H 5 COCHBr.CH 2 COC 6 H 5 , m.p. 141 and 139, are formed from di- 
 benzoyl-ethylene with halogen hydrides, which are easily split off ; with 
 
634 ORGANIC CHEMISTRY 
 
 potassium iodide they are easily transposed to y-iodo-diphenacyl 
 C 6 H 5 COCHI.CH 2 COC 6 H 5 , m.p. 121. Isomeric halogen diphenacyls 
 are formed by the action of alcoholic potash upon phenacyl haloids, 
 C 6 H 5 COCH 2 X ; in contrast with the above compounds they show no 
 ketone or diketone reactions and are marked by the ease of addition of 
 carboxylic acid haloids and halogen hydrides. They are regarded as 
 the various stereo-isomeric forms of the corresponding di-enol forms of 
 the halogen diphenacyls C 6 HC(OH) : CX.CH : C(OH)C 6 H 5 . On reduc- 
 tion they yield diphenacyl. a- and j8-Chloro-diphenaeyl, m.p. 117 and 
 155, a-' and jS-bromo-diphenacyl, m.p. 129 and 161, a-, j3-, and 8- 
 iodo-diphenacyl, m.p. 82-83 with decomposition, m.p. 113 with de- 
 composition, and m.p. I50-I53 with decomposition. If metallic 
 sodium is made to act upon the ether solution of phenacyl iodide, we 
 
 obtain tribenzoyl-trimethylene C 6 H 5 COCH<C^^ 6 2 5 ( B - 36 2 3 86 > 2 4 2 5)- 
 
 \CrlCUL/ 6 rl 5 
 
 Dibenzoyl-ethylene C 6 H 5 COCH : CHCOC 6 H 5 , cis-form, m.p. 134, 
 trans-form, m.p. m, is produced by heating dibenzoyl-malic acid, 
 which splits off 2CO 2 and H 2 O. The cis-form is converted by HC1 into 
 the trans-form, and the latter, by illumination, back into the cis-form. 
 The cis-form reacts more easily than the trans-form with hydrazin, 
 forming diphenyl-pyridazin, and it also forms addition products more 
 readily (B. 35, 168). 
 
 Phenaeyl-benzyl-ketone C 6 H 5 COCH 2 COCH 2 C 6 H 5 , m.p. 54-56, from 
 phenyl-acetic ester and aceto-phenone with sodium in ether. It is 
 isomeric with diphenacyl (B. 34, 1479). 
 
 Desyl-aceto-phenone,a, fi-dibenzoyl-phenyl-ethane C 6 H 5 CO.CH(C 6 H 5 ) . 
 CH 2 .COC 6 H 5 , melting at 126, is produced in the condensation of benzoin 
 and aceto-phenone with potassium cyanide (B. 23, R. 636 ; 26, 60). 
 See B. 29, R. 171, for the action of hydrazin. 
 C 6 H 5 .COCH.C 6 H 5 
 
 Bidesyl I , dibenzoyl-dibenzyl, results when desyl- 
 
 C 6 H 5 .CO.CH.C 6 H 6 
 
 bromide or iodine acts upon sodium desoxy-benzoin (B. 21, 1355 ; 25, 
 285). It melts at 255. Iso-bidesyl, formed simultaneously, melts at 
 161. Bidesyl yields tetraphenyl-pyrrol and tetraphenyl-furfurane, 
 the so-called lepidene. 
 
 a,j8-Dibenzoyl-styrol, anhydro-aceto-phenone-benzile C 6 H 5 CO.CH : C 
 (C 6 H 5 )COC 6 H 5 , m.p. 129, is obtained from benzile and aceto-phenone 
 by the action of caustic potash. When heated it rearranges itself by 
 the migration of a phenyl group into the isomeric triphenyl-croto- 
 lactone, m.p. 118 : 
 
 C 6 H 5 CO.C(C 6 H 5 ) : CHCOC 6 H 5 > CO.C(CeH 5 ) 2 .CH : C(6)C 6 H 5 
 
 Dibenzoyl-styrol a, a, y-Triphenyl-croto-lactone. 
 
 Dibenzoyl-stilbene, acicular oxy-lepidene C 6 H 5 CO.C(C 6 H 5 ) : C(C 6 H 5 ) 
 COC 6 H 5 , m.p. 220, resulting from the oxidation of lepidene (see above) 
 with nitric acid, or of thio-nessal with potassium chlorate and hydro- 
 chloric acid, also yields, on heating, tetraphenyl-croto-lactone, tabular 
 oxy-lepidene, m.p. 136 : 
 
 C 6 H 5 COC(C 6 H 5 ) : C(C 6 H 5 )COC 6 H 5 >COC(C 3 H 5 ) 2 .C(C 6 H 5 : )C(6)C 6 H 5 
 
 Dibenzoyl-stilbene a, a, j8, y-Tetraphenyl-croto-lactone 
 
 Bidesyl results from the reduction of dibenzoyl-stilbene. 
 
w, co-DIPHENYL-BUTANE GROUP 635 
 
 Diphenyl-tetraketone C 6 H 5 .CO.CO.CO.CO.C 6 H 5 (+H 2 O), m.p. 87, 
 is red in colour when hydrous and yellow when anhydrous. It is 
 formed in the oxidation of benzoyl-formom C 6 H 5 .CO.CO.CH(OH) 
 COC 6 H 5) m.p. 170, which is produced, like benzoin, from benzaldehyde 
 by condensing two molecules of phenyl-glyoxal with potassium cyanide. 
 Benzoyl-formoin also results readily from the action of soda upon iso- 
 nitroso-aceto-phenone acetate C 6 H 5 .CO.CH : NO.COCH 3 . Substituted 
 diphenyl-tetraketones have been similarly prepared (B. 25, 3468). 
 
 Diphenyl-tetraketone is a member of the following CO homologous 
 series : 
 
 Diphenyl-ketone, benzo-phenone C 6 H 5 COC 6 H 5 
 Diphenyl-diketone, benzile C 6 H 5 COCOC 6 H 5 
 
 Diphenyl-triketone C 6 H 5 COCOCOC 6 H 5 
 
 Diphenyl-tetraketone C 6 H 5 COCOCOCOC 6 H 5 . 
 
 Hydroxylamine forms but one i, ^-dioxime [C 6 H 5 C(NOH)CO] 2 , m.p. 
 176 with decomposition ; the 2, 3-dioxime or dibenzoyl-glyoxime 
 C 6 H 5 .COC(NOH)C(NOH)CO.C 6 H 5 , m.p. 108 with decomposition, 
 results from the reduction of its peroxide, which is formed in the 
 interaction of nitric acid and aceto-phenone. Hydroxylamine con- 
 verts the 2, 3-dioxime into diphenyl - tetraketoxime C 6 H 5 [C(NOH)] 4 
 C 6 H 5 , m.p. 225 (B. 26, 528). 
 
 Carboxylic Acids. From diphenyl-butadiene the following two 
 acids are derived : 
 
 a-Phenyl-cinnamenyl-acrylic acid, cinnamylidene-phenyl-acetic acid 
 C 6 H 5 C(CO 2 H) : CH.CH : CHC 6 H 5 , m.p. 188, from cinnamic aldehyde 
 and phenyl - acetic acid, and dibenzal-propionic acid C 6 H 5 CH : C 
 (COOH).CH : CHC 6 H 5 , obtained from benzaldehyde and y-phenyl- 
 iso-crotonic acid by Perkin's synthesis. These two diolefm-carboxylic 
 acids have been closely examined by Thiele, as they furnished material 
 for his theory of conjugate double bindings (A. 306, 87-246 ; but see 
 B. 37, 1121). 
 
 The a-phenyl-cinnamenyl-acrylic acid gives with bromine a 
 dibromide, m.p. 175 with decomposition, containing the Br atoms in 
 the i, 4-position, since with alkali it yields a, a-diphenyl-dihydro- 
 furfurane and a brominated acid. On the other hand, the dibromide 
 heated with diethyl-aniline is transposed into the lactone of eorni- 
 cularic acid C 6 H 5 C(COQH) : CH.COCH 2 C 6 H 5 , m.p. 123, which is also 
 produced by the reduction of vulpic acid. The reduction of phenyl- 
 cinnamenyl-acrylic acid produces first 2, 5-diphenyl-pentenic-acid 
 C 6 H 5 CH(COOH)CH : CHCH 2 C 6 H 5 , m.p. 101, which with alkali is 
 isomerised to the a, jS-unsaturated acid, and with glacial acetic sul- 
 phuric acid to the lactone of tetrahydro-eornicularic acid C 6 H 5 CH 
 (COOH)CH 2 .CH(OH)CH 2 C 6 H 5 . Bromine converts the 2, 5-diphenyl- 
 pentenic acid into 1, 3-phenyl-benzyl-A 1 -eroto-lactone 
 
 CgHeC : CH.CH. CHoCfiHc i i -.1 n i- i i i i i j 
 
 co ^ 5 , which with alkali yields hydro-cormculanc acid 
 
 (A. 319, 211). 
 
 Dibenzal-propionic acid also yields a i, 5-dibromide, which is easily 
 converted into bromo-lactone and a diolefin-lactone : benzal-phenyl- 
 
 eroto-lactone C H * CH : ^Q 1 ^ ' 115 ' m.p. 150. a-Phenacyl-cinnamic 
 acid C 6 H 5 CH :C(COOH)CH 2 COC 6 H 5 , m.p. 171, is produced from the 
 
636 ORGANIC CHEMISTRY 
 
 former by alkali. Reduction of the bromo-lactone and diolefin- 
 lactone gives an unstable lactone (i), m.p. 101, and a stable lactone 
 (2), m.p. 67, both of which yield with alkali a-phenacyl-hydro-cinnamic 
 acid (3) : 
 
 (!) CO O (3) COOH (2) CO O 
 
 C 6 H 5 CH 2 .CH.CH : CC 6 H 5 >C 6 H 5 CH 2 CHCH 2 COC 6 H 5 < C 6 H 5 CH 2 C : CH.CHC 6 H 5 . 
 
 Reduction of diphenyl-propionic acid gives a-benzyl-phenyl-iso- 
 erotonic acid C 6 H 5 .CH 2 CH(COOH)CH : CHC 6 H 5 , m.p. 124, distin- 
 guished by the ease with which it produces naphthalin derivatives. 
 With bromine it splits off HBr and produces phenyl-bromo-tetrahydro- 
 naphthoic acid. 
 
 From the nitrile of cinnamenyl-phenyl-acrylic acid is derived 
 p 2 -diamido-diphenyl-cyano-butadiene NH 2 [4]C 6 H 4 CH : CH.CH : C(CN) 
 C 6 H 4 [4]NH 2 , m.p. 196, which, like benzidin and p 2 -diamido-stilbene, 
 is a generator of substantive cotton dyes (B. 34, 3109). 
 
 Diphenyl - butadiene - acetic acid C 6 H 5 CH : CH.CH : C(C 6 H 5 )CH 2 
 COOH, m.p. 190, from cinnamic aldehyde and phenyl-succinic acid, 
 on boiling with acetic anhydride, yields diphenyl-phenol (B. 36, 1407). 
 
 The ester of benzoyl-phenacyl-aeetic acid, a, /3-dibenzoyl-propionie 
 acid C 6 H 5 .CO.CH 2 .CH(CO.C 6 H 5 )COOR, is obtained from benzoyl-acetic 
 ester with phenacyl bromide. In the ketone decomposition it yields 
 diphenacyl ; and by the acid decomposition, benzoyl-propionic acid 
 and benzoic acid. Iso-oxalyl-dibenzyl-ketone, melting at 24o-242, 
 may be referred to benzoyl-oxalyl-phenyl-acetic acid C 6 H5.CH 2 .CO. 
 CO.CH(C 6 H 5 ).COOH, isomeric with dibenzoyl-propionic acid. It is 
 formed on heating oxalyl-dibenzyl-ketone beyond its melting-point 
 (A. 284, 293) : 
 
 C 6 H 5 C : C(OH).CO.CH.C 6 H 5 __ C 6 H 5 C : C(OH).C : CH.C 6 H 5 
 
 CO 
 
 Alkalies convert isoxalyl-benzyl-ketone, just like pulvic acid richer 
 in CO 2 , into dibenzyl-glycollic acid. 
 
 Dibenzylidene-succinic acid C 6 H 5 CH : C(COOH).C(COOH) : 
 CHC 6 H 5 , melting with decomposition at 201, and benzylidene-y- 
 diphenyl-itaeonie acid (C 6 H 5 ) 2 C : C(COOH).C(COOH) : CH.C 6 H 5 , are 
 obtained by the condensation of succinic ester (i) with two molecules 
 of benzaldehyde, and (2) with benzo-phenone and benzaldehyde by 
 means of sodium ethylate (B. 30, 94 ; 37, 2240). By reduction with 
 Na amalgam they form a mixture of two cis-trans isomeric diphenyl- 
 and triphenyl-butane-dicarboxylic acids (B. 37, 2662). By illumina- 
 tion the dibenzylidene-succinic anhydride is oxidised and converted 
 into the anhydride of i-phenyl-naphthalin-2, 3-dicarboxylic acid 
 (B. 40, 3374) : 
 
 C 6 H 5 CH:C C0\ _ c R /CH=rC.CO\ 
 C 6 H 5 CH : C CO/ 4 \C(C 6 H 5 ) : C.CO/ 
 
 C 6 H 5 .CO.CH.C0 2 H 
 
 Dibenzoyl - succinic acid . Its ethyl ester, 
 
 C 6 H 5 .CO.CH.C0 2 H 
 
 melting at 129, is obtained from sodium-benzoyl-acetic ester by the 
 action of iodine, just as we form diaceto-succinic ester from aceto-acetic 
 ester. By the elimination of water there results diphenyl-furfumne- 
 
co, oj-DIPHENYL-BUTANE GROUP 637 
 
 dicarboxylic ester. The esters of the acid appear in three forms, of which 
 the unstable variety, soluble in alkalies, is probably the enol-form C 6 H 5 
 C(OH) : C(COOH) : C(COOH) : C(OH)C 6 H 5 , while the other two repre- 
 sent the syn- and anti-modifications of the keto-form (B. 29, R. 962). 
 
 Dibenzoyl-maleic acid ester c^'coCco^H 5 ' m ' p ' 75 ' from 
 disodium-dibenzoyl-succinic acid ester with iodine, is transposed by 
 heat into dibenzoyl-fumarie acid 'J5?^S^ff*, m.p. 88. The 
 
 UVJ 2 l^ 2 -"5'"'*-'*-"-'6-"-5 
 
 maleinoid ester condenses more easily than the fumaroid with hydrazin 
 to form diphenyl-pyridazin-carboxylic ester (q.v.). The potassium salts 
 produced by the acidulation of the esters give, on acidulation, a 
 hydrate of dibenzoyl-ethylene-dicarboxylic acid, the so-called dibenzoyl- 
 
 malic acid c 6 H 5 coCHCO C H 2H (?) ' which on heatin S loses water and 
 2CO 2 , and passes into dibenzoyl-ethylene (B. 33, 3784). 
 
 Diphenyl-oxalyl-diacetie acid, diphenyl-ketipic acid COOH.CH(C 6 H 5 ) 
 CO.CO.CH(C 6 H 5 )COOH is isomeric with dibenzoyl-succinic acid. Its 
 dinitrile, melting at 270 with decomposition, is produced by the con- 
 densation of oxalic ester with two molecules of benzyl cyanide. When 
 saponified with hydrochloric or sulphuric acid it yields not the free 
 acid, but passes at once into its anhydride, a monolactone, pulvic acid 
 
 OOC.CH(C 6 H 5 )CO.C : C(C 6 H 5 )COOH, melting at 214, and a dilactone 
 OOC.C(C 6 H 5 ) : C.C : C(C 6 H 5 )COO. Pulvic acid may also be prepared 
 
 from vulpic acid, C 19 H 14 O 5 , consisting of yellow prisms, melting at 110, 
 and found in a certain moss and in the lichen Cetraria vulpina, by boiling 
 it with lime-water. Sodium ethylate converts pulvic acid back into 
 salts of vulpic acid. The latter is therefore very probably to be 
 regarded as a methyl ether of pulvic acid (B. 27, R. 869 ; A. 288, 14). 
 Zinc dust and ammonia reduce pulvic acid to hydro-cornieularic acid, 
 a, -diphenyl-lcevulinic acid C 6 H 5 .CH 2 .CO.CH 2 .CH(C 6 H 5 )COOH, melting 
 at 134. Distilled with lime, it yields phenyl-ethyl-benzyl-ketone, and 
 when heated with caustic potash the products are toluene and phenyl- 
 succinic acid. Boiling alkalies decompose pulvic and vulpic acids into 
 2CO 2 and dibenzyl-glycollic acid. If it be assumed that diphenyl- 
 ketipic acid is formed at first, then this reaction, discarding the evolu- 
 tion of CO 2 , is an analogue of the benzilic acid transposition : 
 
 C 6 H 5 .CH(COOH) .CO C 6 H 6 .CH 2X 
 
 | 5 > >C(OH)COOH. 
 
 C 6 H 5 .CH(COOH).CO - 2CO C 6 H 5 .CH/ 
 
 Ethane-dibenzoyl-o 2 -diearboxylic acid COOH.C 6 H 4 CO.CH 2 .CH 2 
 CO.C 6 H 4 .COOH, is another isomeride of dibenzoyl-succinic acid. It 
 
 melts at 166. It is made by boiling ethine-diphthalyl 6.OC.C 6 H 4 .C : 
 
 CH.CH : C.C 6 H 4 .COO, melting above 350, the dilactone corresponding 
 to it, with alkalies. Ethine-diphthalyl results from the condensation 
 of two molecules of phthalic anhydride with succinic acid when two 
 molecules of carbon dioxide are split off (B. 17, 2770). Sodium alcohol- 
 ate rearranges it into bis-diketo-hydrindene. 
 
 F. cu,cu - Diphenyl-pentane Group. y - Diphenyl - methylene - a, 
 
638 ORGANIC CHEMISTRY 
 
 e-diphenyl-pentadiene (C 6 H 5 CH : CH) 2 : C : C(C 6 H 5 ) 2 , sulphur-yellow 
 crystals, m.p. 174, from diphenyl-ketene and dibenzal-acetone (B. 41, 
 
 Ketones. i. The diolefin - ketones of this group are generally 
 obtained by condensation of benzaldehydes (two molecules) with 
 ketones (one molecule) which contain the group CH 2 COCH 2 : 
 
 2C 6 H 5 CHO+CH 3 COCH 3 =C 6 H 5 .CH : CHCOCH : CHC 6 H 5 +2H 2 O. 
 
 Dibenzylidene - acetone, dibenzal - acetone C 6 H 5 CH : CH.COCH : 
 CHC 6 H 5 , yellow needles, m.p. 112 ; oxime, m.p. 143, gives two 
 isomeric hydroxylamine oximes C 6 H 5 CH : CHC(NOH)CH 2 .CH(NHOH) 
 C 6 H 5 , m.p. 165 and 201 (C. 1900, 1. 336) by the reduction of a second 
 molecule of hydroxylamine. 
 
 The dibenzyl-acetone gives with HC1 not only the normal colourless 
 addition products, but also a yellow unstable monochlorohydrate 
 which in solution partly splits up into its components and unites with 
 a second molecule HC1 or metallic salts like ferric or mercuric chloride 
 to intensely red double compounds (B. 37, 3277, 3364). 
 
 By the action of acetic anhydride and concentrated sulphuric acid, 
 dibenzal-acetone takes up water and is changed into diphenyl-eyelo- 
 
 pentenolone c^C^H*)) 00 ' m 'P- r 7 6 ( B - 37 > "33). 
 
 Dibenzal-acetone dichloride, dicinnamenyl-dichlow-methane (C 6 H 5 
 CH : CH) 2 CC1 2 , m.p. 77, produced by the action of PC1 5 upon dibenzal- 
 acetone in benzene solution, shows in its properties a far-reaching 
 analogy with triphenyl-chloro-methane. It dissolves in concentrated 
 sulphuric acid with a violet colour, and gives, with metallic salts like 
 mercuric and stannic chloride, double compounds of the same colour. 
 Its purple solution in SO 2 contacts the electric current. One of the 
 two chlorine atoms is very lightly bound and can easily be exchanged 
 for other groups like OH, OCH 3 , etc. The dieinnamenyl-ehloro- 
 carbinol (C 6 H 5 CH : CH) 2 C(OH)C1, m.p. 56, formed by treatment with 
 moist silver oxide, is very stable and resembles triphenyl-carbinol. 
 Like the latter, it dissolves with an intense colour in concentrated 
 sulphuric acid. It is very easily esterified (methyl ether, m.p. 55), 
 and is easily converted by gaseous HC1 into the dichloride, and by 
 HBr into chloro-bromide in which the bromine atom shows the chief 
 reaction. The reason for this property is to be found in the particu- 
 larly strong valency binding by the cinnamenyl group, which surpasses 
 that of the phenyl group, since in the benzo-phenone chloride C 6 H 5 CC1 2 
 C 6 H 5 no loosening of the chlorine atom is to be observed, whereas the 
 dichloride of the benzylidene-aceto-phenone C 6 H 5 CH : CH.CC1 2 C 6 H 5 
 shows similar phenomena (B. 39, 2977 ; 40, 2689 ; A. 370, 315). 
 
 Benzal-benzyl-acetone C 6 H 5 CH : CHCOCH 2 CH 2 C 6 H 5 , m.p. 53, from 
 benzaldehyde and benzyl-acetone with soda. Sodium amalgam 
 reduces it to dibenzyl-acetone (C 6 H 6 CH 2 CH 2 ) 2 CO, b.p. 130 28o-285 
 (A. 330, 185). p 2 -Dinitro-dibenzyl-acetone, see B. 37, 1993. 
 
 o-Oxy-dibenzal-acetone, yellow flakes, m.p. 139 (B. 31, 728). 
 
 o 2 -Dioxy-dibenzal-acetone, o-dicumarketone, m.p. 160, p 2 -dioxy- 
 dibenzal-acetone, m.p. 238, orange-yellow crystals, the unstable 
 modification consisting of dark-green flakes (B. 26, 129). Dibenzal- 
 diethyl-ketone, m.p. 122 (B. 31, 1886). 
 
o>, oj-DIPHENYL-PENTANE GROUP 639 
 
 Cmnamylidene-aceto-phenone C 6 H 5 CH : CH.CH : CHCOC 6 H 5 , m.p. 
 103, from cinnamic aldehyde and aceto-phenone. Its oxime, m.p. 131, 
 is condensed by heating to a 1 a 1 -diphenyl-pyridin (B. 28, 1730) ; 
 homologues, see B. 35, 1065. 
 
 Dibenzoyl-propane CH 2 (CH 2 COC 6 H 5 ) 2 , m.p. 67, is formed from 
 glutaryl-chloride-benzene and A1C1 3 . Also by splitting up a 1 a 1 - 
 dibenzoyl-glutaric ester obtained from benzoyl - acetic ester with 
 CH 2 I 2 or formaldehyde. 
 
 Dibenzoyl-diphenyl-propane CH 2 [CH(C 6 H 5 )COC 6 H 5 ] 2 , m.p. 146, 
 from formaldehyde and desoxy-benzoin. The reduction of its i, 5- 
 diketone produces cyclic pinacones of the pentamethylene group 
 (B. 24, R. 323 ; A. 302, 215, 223). 
 
 i, 5-Diketones of this group are obtained by condensing benzalde- 
 hydes (one molecule) and aceto-phenones (two molecules) with sodium 
 hydroxide : benzylidene - diaceto - phenone C 6 H 5 CH(CH 2 .CO.C 6 H 5 ) 2 , 
 m.p. 85, and o-oxy-benzylidene-diaceto-phenone (OH)[2]C 6 H 4 (CH 2 . 
 CO.C 6 H 5 ) 2 , melting at 131. By varying the conditions and condensing 
 two molecules of benzaldehyde with three molecules of aceto-phenone, 
 two isomeric dibenzylidene-triaceto-phenones (C 6 H 5 CH) 2 (CH 2 COC 6 H 5 ) 3 , 
 melting at 198 and 256 respectively, are produced. 
 
 Benzamarone, benzylidene-bis-desoxy-benzom C 6 H5COCH(C 6 H 5 )CH 
 (C 6 H 5 ).CH(C 6 H 5 )COC 6 H 5 (?), exists in two modifications, melting at 
 219 and 180. It is prepared by condensing benzaldehyde with 
 desoxy-benzoin, as well as by the addition of desoxy-benzoin to benzyl- 
 idene-desoxy-benzoin by the aid of sodium ethylate. Similarly, desoxy- 
 benzoin attaches itself to the unsaturated unions of other olefin 
 derivatives e.g. a-phenyl-cinnamo-nitrile, benzal-aceto-acetic ester, 
 benzal-benzoyl-pyro-racemic ester, etc. (B. 25, 1087). By decom- 
 position with sodium ethylate, benzamarone yields the sodium salt of 
 amaric acid C 23 H 20 O 3 , and with sodium iso-butylate it forms dimethyl- 
 amaric acid C 25 H 26 O 3 (A. 275, 50). 
 
 The dry distillation of benzamarone produces desoxy-benzoin, 
 benzylidene-desoxy-benzoin, and a body isomeric with the latter (B. 
 26, 818). Hydroxylamine changes it quite readily into pentaphenyl- 
 pyridin. 
 
 Carboxyl Derivatives of the a>, a)-Diphenyl-pentane Group. Styryl- 
 
 (- TJ (^TJ- . P"H"\ 
 
 phenaeyl-propionic acid r 5 ;; 5 ;; ' rp >CHCH 2 COOH, m.p. 125, from the 
 
 v^ 6 r! 5 ^U.v^rl 2 / 
 
 condensation product of cinnamylidene-aceto-phenone with malonic 
 ester by saponincation and rejection of CO 2 . On reduction it yields 
 phenacyl-succinic acid C 6 H 5 COCH 2 CH(COOH).CH 2 COOH (C. 1903, 
 II. 944). 
 
 Diphenyl-acetic acid (C 6 H 5 COCH 2 ) 2 CHCO 2 H, m.p. 133, from 
 diphenacyl-malonic ester (C 6 H 5 COCH 2 ) 2 C(CO 2 R) 2 or diphenacyl-aceto- 
 acetic ester (C 6 H 5 COCH 2 ) 2 C(COCH 3 )COOC 2 H 5 , m.p. 83, the products 
 of the action of phenacyl bromide upon malonic ester and aceto-acetic 
 ester (B. 22, 3225). It is also formed by alkaline condensation of 
 aceto-phenone with glyoxylic acid, as well as the action of cold soda 
 upon benzoyl-acrylic acid, wherein the latter splits up into aceto- 
 phenone and glyoxylic acid (C. 1909, II. 125). Diphenacyl-acetic acid, 
 being an e-diketone, forms with ammonia a pyridin derivative (B. 29, 
 
640 ORGANIC CHEMISTRY 
 
 Dibenzyl-aeetone-dicarboxylie ester C 6 H 5 CH 2 (C0 2 R)COCH(CO 2 R) 
 CH 2 C 6 H 5 is formed on benzylating acetone-dicarboxylic ester (Vol. I.), 
 besides the monobenzylated and tribenzylated product (B. 34, 1996). 
 
 Acetone-diphthalide CO[CH 2 CHC 6 H 4 [2]COO] 2 , m.p. 137, from 
 phthal-aldehydic acid and acetone, besides acetonyl-monophthalide 
 (C. 1898, II. 980). 
 
 Benzylidene-bis-benzoyl-acetic ester C 6 H 5 CH[CH(CO 2 R)COC 6 H5]2 
 from benzal-benzoyl-acetic ester with benzoyl-acetic ester. It is easily 
 split by alcoholic sodium ethylate into these components (B. 33, 3183). 
 
 G. w, aj-Diphenyl-hexane Group and Higher Homologues. 1, 6- 
 Diphenyl-hexadiene C 6 H 5 CH : CH.CH 2 .CH 2 .CH : CHC 6 H 5 , m.p. 82, is 
 formed, besides an isomeric liquid hydrocarbon, by the action of Mg 
 upon cinnamyl chloride C 6 H 5 CH : CH.CH 2 C1 (B. 43, 172). Tetra- 
 phenyl-hexatriene C 6 H 5 CH : CH.CH : CH.C(C 6 H 5 ) : C(C 6 H 5 ) 2 , yellow 
 prisms, m.p. 159, from diphenyl-ketone and cinnamylidene-aceto- 
 phenone (B. 42, 4249). Hydro-cinnamoin C 6 H 5 CH : CH.CH(OH). 
 CH(OH).CH : CHC 6 H 5 , m.p. 154, is obtained, besides other products, 
 by the reduction of cinnamic aldehyde with copper zinc in alcohol 
 
 (B. 32, 1296). Dibenzoyl-diphenyl-butadiene 9'^c ^ : ^ 6 S 5 (?), 
 
 L^g-TLgULJU-n. . Ut^gJtl 5 
 
 m.p. 192, from benzile and aceto-phenone, can be converted by reduc- 
 tion into tetraphenyl-benzol and its derivatives (A. 302, 195). 
 
 Oxalyl-diaeeto-phenone C 6 H 5 COCH 2 COCOCH 2 COC 6 H 5 , m.p. 180, 
 is formed in the condensation of two molecules of aceto-phenone and 
 oxalic ester with sodium alcoholate. Consult B. 28, 1206, for the 
 reduction-products of this tetraketone. 
 
 w, oj-Diphenyl-diketo-hexane (C 6 H 5 COCH 2 CH 2 ) 2 . Diphenyl-diketo- 
 octane (C 6 H 5 COCH 2 CH 2 CH 2 ) 2 , and diphenyl-diketo-nonane (C 6 H 5 CO. 
 CH 2 .CH 2 .CH 2 ) 2 CH 2 , are prepared from the chlorides of adipic acid, 
 sebacic acid, and azelaic acid by means of benzene and aluminium 
 chloride (B. 29, R. 1157). Cinnamylene-benzylidene-acetone C<.H 5 CH : 
 CH.CH : CH.COCH : CHC 6 .H 5 , m.p. 106, is derived from 6o,co-diphenyl- 
 heptane. It is formed from cinnamylene-acetone and benzaldehyde 
 (B. 29, 615). Cinnamylene-benzylidene-acetone C 6 H 5 CH : CH.CH : CH. 
 COCH : CHC 6 H 5 , m.p. 106, is derived from o>, cu-diphenyl-heptane. 
 It is formed from cinnamylene-acetone and benzaldehyde (B. 29, 615). 
 Diphenyl-butadiene, diphenyl-octa-tetrene C 6 H 5 CH : CH.CH : CH.CH : 
 CH.CH : CHC 6 H 5 , m.p. 225 with decomposition, golden - yellow 
 flakes, is formed besides dicinnamylidene - succinic anhydride 
 
 QH'CH : CtLCH : Cco)' m ' P ' 2I5 ' brick - red needles, by condensa- 
 tion of cinnamic aldehyde with sodium succinate by acetic anhydride 
 (A. 331, 165). A stereo-isomeric (?) white diphenyl-octa-tetrene, m.p. 
 124, is formed from cinnamic aldehyde, succinic ester, and sodium 
 ethylate, besides other products (B. 34, 2190). Illumination converts 
 the yellow into the white hydrocarbon (B. 42, 565). 
 
 B. CONDENSED NUCLEI. 
 
 The condensed nuclei to be discussed in the following section are 
 characterised by the fact that in them C atoms of the benzene nuclei 
 participate in the formation of other carbocyclic rings. 
 
CONDENSED NUCLEI 641 
 
 Substances to which bicyclic formulae are attributed have 
 already been mentioned. Compare bicyclo-pentane, bicyclic ketone, 
 carone, thujone, pinene, camphene, tricyclene, camphor, fenchone, 
 etc. It should be noted that the capacity of forming bicyclic 
 combinations in the hydro-aromatic substances is more varied 
 than in the benzene derivatives proper, and is not confined to the 
 i, 2-position. 
 
 The bicyclic system of carone | I yC 7, representing the 
 
 c c c/ 
 
 321 
 
 condensed benzene-trimethylene ring, and whose hypothetical hydrogen 
 compound is called norcarane, has been made accessible, in a more 
 general synthetic manner, by heating diazo-acetic ester with benzene 
 or its derivatives (Buchner, B. 33, 3453 ; 34, 982 ; 36, 3502 ; 37, 931) : 
 
 CH=CH CH K CH=CH CH V 
 
 || + || >CHC0 2 C 2 H 5 =| I >CHC0 2 C 2 H 5 +N Z . 
 
 CH=CH CH N/ CH=CH CH/ 
 
 A 2 ' 4 -Norcaradiene-7-earboxylic ethyl ester, pseudo-phenyl-acetic ester, 
 followed by 
 
 A^Norcaradiene - 7 - carboxylic ethyl ester, pseudo-phenyl-acetic 
 ester C 6 H 6 CHCO 2 C 2 H 5 , is formed from benzene and diazo-acetic ester 
 by heating under pressure to I35-I4O. The raw ester, b.p. 13 108, 
 partly converted into j3-cyclo-heptatriene-carboxylic ester, gives, 
 with concentrated sulphuric acid, a red colour passing into indigo blue. 
 With ammonia we obtain the crystalline amide, m.p. 141, which on 
 saponification with sulphuric acid gives the oily, free acid. The latter 
 with bromine gives a dibromide, m.p. 160 with decomposition, and a 
 tetrabromide, m.p. 235 with decomposition. Oxidation with per- 
 manganate is complicated. It results in benzoic acid, o-, and p- 
 phthalic acid, and trimethylene-tricarboxylic acid (splitting of the 
 benzene ring). Heating under pressure transposes the ester into 
 j3-cyclo-heptatriene-carboxylic ester, while boiling the ester or amide 
 with alkalies produces a-cyclo-heptatriene-carboxylic acid (splitting of 
 the trimethylene ring between i and 6). Treatment with concentrated 
 sulphuric acid transposes the amide into phenyl-acetamide C 6 H 5 .CH 2 
 CONH 2 (splitting of the trimethylene ring between i and 7). 
 
 A 2 , 4 -3-Methyl-norcaradiene-carboxylic ester, pseudo-tolyl-acetic ester 
 CH 3 .C 6 H5 : CHCO 2 C 2 H 5 , b.p. 12 I22-I26, from toluol and diazo-acetic 
 ester, amide, m.p. 131, gives on boiling with 30 per cent, sulphuric acid, 
 p-tolyl-acetic acid ; by prolonged shaking with ammonia, methyl- 
 cyclo-heptatriene-carboxylic ester, m.p. 108. 
 
 3, 5-Dimethyl-norcaradiene-earboxylie ester, pseudo-xylyl-acetic ester 
 (CH 3 ) 2 C 6 H 4 : CHCO 2 C 2 H 5 , b.p. 10 I25-I35, from m-xylol and diazo- 
 acetic ester, amide, m.p. 142, gives, with sulphuric acid, 2, 4-dimethyl- 
 phenyl-acetic acid (A. 258, i). 
 
 1, 7 - Norcarane - dicarboxylic ester CO 2 C 2 H 5 .C 6 H 9 : CHCO 2 C 2 H 5 , 
 b.p. 18 160, from A 1 -tetrahydro-benzoic ester with diazo-acetic ester ; 
 the acid, m.p. 153, gives an anhydride, m.p. 87. 
 
 C 6 H 4 CH. 
 
 Benzo-norearadiene-carboxylic ester i | NcHCO 2 c 2 H 5 , b.p. u 
 
 CH =CH CH/ 
 VOL. II. 2 T 
 
642 ORGANIC CHEMISTRY 
 
 i63-i64, from naphthalene with diazo-acetic ester. Acid, m.p. 166 ; 
 amide, m.p. 217. Oxidation produces carboxy-phenyl-trimethylene- 
 diearboxylic acid C 2 H - C 6H 4 CH \ CHCOgH> which has been further dis- 
 
 CO 2 H.CH/ 
 
 integrated to trimethylene-tricarboxylic acid. In this connection 
 some substances should be mentioned which are derived from a con- 
 densed benzene and heptamethyl ring, benzo-cyelo-heptane. 
 
 Benzo-cyclo-heptanone C 6 H 4 {^^ 2 ' 2 ^ CH 2' b -P- 2 7> is formed 
 
 v. |_2jv-<VJ . Crlg/ 
 
 by condensation of A-phenyl-valeric acid chloride by means of A1C1 3 ; 
 its oxime, m.p. 109, gives on reduction benzo-a-amino-cyclo-heptane, 
 whose chlorohydrate, on heating, decomposes into sal ammoniac and 
 
 benzo-cyclo-heptene C 6 H 4 ^~ 2 :H 2 , b.p. 234. The latter is 
 
 L l_2JL/xl - \stis 
 
 split up by oxidation to o-phenylene-butyro-carboxylic acid (C. 1903, 
 I. 586, 882). 
 
 Benzo-eyclo-heptadione c 6 H 4 ] ' 2 H 2 , m.p. 46, is formed by 
 
 ketone-splitting of phthalyl-glutarie esters C - 
 
 obtained by condensation of phthalic ester and glutaric ester by means 
 of sodium alcoholate (B. 32, 2227). 
 
 Benzo-eyclo-heptadienone ^{|*S| ; ^> co , m>p ' 67 ' is formed 
 from its dicarboxylic acid, m.p. 210. The diethyl ester, m.p. 95, is 
 formed by condensation of o-ph thai-aldehyde with acetone-dicarboxylic 
 ester by means of diethylamine. 
 
 #0wo/ogws of benzo-cyclo-heptadienone are formed by the condensation 
 of o-ph thai-aldehyde with methyl-ethyl-ketone, diethyl-ketone, dibenzyl- 
 ketone, etc., together with acyl-hydrindones. Sodium and alcohol 
 reduce them to the corresponding benzo-cyclo-heptanols (A. 377, i). 
 
 Of greater importance are the combinations of the benzene nuclei 
 with five-member ed nuclei, and of benzene nuclei with each other : 
 
 / 
 
 CH 
 
 C CH 
 
 pTT PTT 
 
 ,/ CH \ / CH \ 
 
 CH C C CH 
 
 XH^ /CH^ 
 CH C CH 
 
 C'H 
 
 II II 
 C CH 
 
 JH 
 
 II II 1 
 
 C^/C CH 
 
 CH 
 
 II 
 C 
 
 - 
 
 s 
 
 -W/VLT 
 ^Jnr L/rl 2 
 
 V 
 
 H/ CH^CH^ 
 
 x ct 
 
 [/ N QP 
 
 -i// 
 
 
 Indene 
 
 
 Fluorene 
 
 Naphthalene 
 
 
 CH=CH 
 
 v^Jri v^jri i^i-j /^T-T c*\^ 
 
 
 CH C 
 
 C 
 
 CH CH C \ 
 
 Y 
 
 % CH 
 
 
 
 \ / 
 CH C 
 
 \ /' 1 II i 
 
 C CH CH C 1 
 
 C 
 
 JH 
 
 
 
 \H 
 
 =^ 
 
 
 H/^C 
 
 H/ 
 
 
 Phenanthrene Anthracene. 
 
 Although these condensed nuclei, as a rule, continue to manifest 
 their aromatic character, they exhibit in their behaviour, in har- 
 mony with their peculiar structure, a series of wide differences from 
 the true benzene compounds (see Naphthalene). They are eventually, 
 by suitable oxidations, changed, like the homologues of benzene, into 
 benzene-carboxylic acids. The parent hydrocarbons of these groups 
 
INDENE AND HYDRINDENE GROUP 643 
 
 occur, like benzene, chiefly in coal-tar, from which they are obtained 
 in greater or lesser amount. Naphthalene is technically important ; 
 this is especially true of anthracene, the hydrocarbon of alizarin. 
 
 I. INDENE AND HYDRINDENE GROUP. 
 
 Indene Hydrindene. 
 
 Indene has received its name from indol, because of its similarity 
 to the latter in structure. By introducing NH into the methylene 
 group of indene the formula of indol results. 
 
 Indene C 9 H 6 is an oil, boiling at 178 ; its specific gravity is 
 1-040 at 15. It occurs, together with cumarone, to which it is very 
 similar in its behaviour (B. 28, 114), in that fraction of coal-tar boiling 
 at i76-i82, and can be extracted from it by means of its picric acid 
 derivative (B. 23, 3276). Very appreciable amounts of indene are also 
 present in the condensation products resulting from the chilling of 
 illuminating gas (B. 28, 1331). It can also be obtained by the dis- 
 tillation of the calcium salt of synthetic hydrindene-carboxylic acid 
 (B. 27, R. 465)- 
 
 It is best formed by heating a-hydrindamine chlorohydrate. 
 Indene absorbs oxygen from the air and polymerises to indene resin 
 on standing, heating, or treatment with concentrated sulphuric acid. 
 It seems partly to be decomposed into truxene and hydrindene (B. 33, 
 2257 ; 36, 640). With chlorine and bromine it combines to form 
 dichloro- and dibromo-hydrindene. It also forms nitroso-chloride and 
 nitrosite like the terpenes (B. 28, 1331). By treatment with sodium 
 and alcohol, indene is reduced to hydrindene. At incandescent heat 
 two molecules indene give up four H atoms to form chrysene. 
 
 The hydrogen atoms of the CH ? group in indene show a similar 
 reactivity to those in cyclo-pentadiene. With oxalic ester it forms 
 indene-oxalic ester, and with aldehydes, by alkaline condensation, in- 
 
 xCl_ CH 8 
 tensely colouredhy drocarbons derived from benzo-f ulvene C 6 H 4 <^ \CH . 
 
 Heating with halogen alkyl and caustic alkali produces mono- and di- 
 alkylated indenes. It is remarkable that the benzyl-indene obtained 
 by reducing benzylidene-indene with aluminium amalgam, which must 
 
 Q CH H C 
 be regarded as C 8 H 4 / /CH* 5 on account of its condensation with 
 
 Crio 
 
 / CH \ 
 
 benzaldehyde, is identical with the a-benzyl-indene C 6 H 4 < >CH 
 
 X CH/CH 2 C 6 H 5 
 
 obtained by benzylating indene. There is therefore no isomerism 
 between the a- and y-alkyl-indenes (A. 347, 249). 
 
 With benzaldehyde, indene combines to oxy-benzyl-indene, which 
 partly passes into benzylidene-indene C 9 H 6 : CHC 6 H 5 , m.p. 88, yellow 
 flakes, and partly combines with the second molecule of benzaldehyde 
 to oxy-benzyl-benzylidene-indene C 9 H 5 .CH(OH)C 6 H 5 (: CHC 6 H 5 ), m.p. 
 135, yellow crystals. Cinnamylidene-indene C 9 H 6 : CH.CH : CHC 6 H 5 , 
 m.p. 190, yellowish-red needles. 
 
644 ORGANIC CHEMISTRY 
 
 Bz.-bromo-indene C 6 H 3 Br(C 2 H 4 ), b.p. 243, is formed from hydrin- 
 dene and bromine (B. 26, 2251). It yields bromo-phthalic acid upon 
 oxidation. 
 
 Indene derivatives are obtained synthetically by the following 
 methods, which to some extent recall the syntheses of the penta- 
 methylene compounds : 
 
 i. Benzene compounds, having the group C 6 H 5 .C.C.CO, split off 
 water and condense to indene derivatives : (a) Nitro-a-alkyl-cinnamic 
 aldehydes yield amido-j8-alkyl-indenes (B. 22, 1830) : 
 
 Nitro-a-methyl-cinnamo-aldehyde Amido-/3-methyl-indene. 
 
 Similarly, benzyl-acetone and benzyl-aceto-acetic ester yield 
 y-methyl-indene and y-methyl-indene-j8-carboxylic acid (B. 20, 1574 ; 
 A. 247, 157) when they are heated with sulphuric acid : 
 
 5X 2 -- /CH;. C 6 H 5 v >CH.CO 2 H -- >C 6 H 
 
 X CH/ XH X CH/ CI 
 
 Benzyl-acetone ) -Methyl-indene Benzyl -acetic acid Methyl-indene-carboxylic 
 
 acid. 
 
 (b) Substituted cinnamic acids yield indone derivatives when they 
 are treated with hot sulphuric acid, just as the hydro-cinnamic acids, 
 alkylised in the nucleus and in the side chain, yield dihydro-indones. 
 Cinnamic and hydro-cinnamic acids themselves react with as little 
 readiness as cinnamic aldehyde (A. 247, 140 ; B. 25, 2095, 2129) : 
 
 HOCO\ __ /CO \ 
 
 C H '\CBr=,/ CBr C H *\CBr/ CBr ' 
 
 Dibromo-cinnamic acid Dibromo-indone. 
 
 HOCCK /CO 
 
 a-Phenyl-hydro-cinnamic acid /S-Phenyl-hydrindone. 
 
 2. The hydrindene derivatives have been obtained in the same 
 manner as the tetra- and pentamethylene derivatives : by the action of 
 xylylene halides upon malonic ester and sodium alcoholate (B. 17, 125 ; 
 18, 378) : 
 
 /CH 2 Br C0 2 R /CH 2 
 
 3. The formation of ay-diketo-hydrindenes from p-phthalic esters 
 and fatty-acid esters or ketones (A. 252, 72 ; B. 27, 104, R. 19) corre- 
 sponds to the condensation of oxalic esters to pentamethylene 
 derivatives : 
 
 * T T "O 
 
 36. The phthalide compounds, of the formula 
 
 formed from phthalic anhydride and fatty acids, are transposed by 
 sodium alcoholates into the sodium derivatives of the isomeric diketo- 
 hydrindenes (B. 26, 954, 2576) : 
 
INDENE AND HYDRINDENE GROUP 645 
 
 40. The formation of dihydrindones by the distillation of salts of 
 o-phenylene-diacetic acid and o-hydro-cinnamic acid (B. 26, 222, 
 R. 708) corresponds to the cyclic ketone formation of dicarboxylic 
 acids of the adipic acid series : 
 
 /CH 2 .COOH _ /CH 2 \ 
 
 C H4 \CH.COOH ' C6H *\CH/ 
 
 46. Corresponding to the cyclic aceto-acetic ester condensation 
 (P- 5)> we have the formation of hydrindone-carboxylic esters by the 
 action of Na or Na alcoholate upon the esters of o-phenylene-diacetic 
 acid or o-hydro-cinnamo-carboxylic acid : 
 CH 2 .CH 2 COOR 
 
 / 
 C H4 \ 
 
 COOR ' ~"*\CO /~ H - C( 
 
 Similarly, we obtain from the o-phenylene-diaceto-nitrile, by means 
 of sodium alcoholate, a-cyano-j3-imino-hydrindene (C. 1908, I. 1274) : 
 
 /CH 2 CN /CH 2 \C=NH 
 
 Ce 4 \CH 2 CN 6 , 4 \CH^_CN 
 
 5. Hydrindone derivatives are formed by alkaline condensation 
 from o-phthal-aldehyde with methyl-ketones and methyl-ketone- 
 carboxylic acids (A. 347, 112 ; 369, 287) : 
 
 6. The formation of indene derivatives from naphthalene deriva- 
 tives is rather remarkable ; a six-membered benzene ring is rearranged 
 to a ring of five members similar to the production of pentamethylene 
 derivatives from the benzenes, or fluorene compounds from phen- 
 anthraquinone. This change occurs by the action of chlorine or hypo- 
 chlorous acid upon the naphthols, naphtho-quinones, amido-naphthols, 
 etc. The first product consists of naphthalene keto-derivatives with 
 the groups CO. CO or CO.CC1 2 ; these sustain the decomposition 
 (B. 20, 2890 ; 21, 2719). Thus, dichloro-j8-naphtho-quinone yields 
 dichloroxy-indene-carboxylic acid : 
 
 ,C0 2 H 
 
 /CO CO /C(OH) 
 
 C 6 H 4 < - > C 6 H 4 < 
 
 x:ci=cci x cci 
 
 Dichloro-/S-naphtho-quinone Dichloroxy-indene-carboxylic acid. 
 
 Indene Derivatives. y (a)-Methyl-indene C 6 H 4 : C 3 H 3 .CH 3 , b.p. 206, 
 is formed by methylating indene, and, synthetically, from benzyl- 
 acetone, also from its carboxylic acid by splitting off CO 2 . 
 y (a)-Benzyl-indene C 6 H 4 : C 3 H 3 .CH 2 C 6 H 5 , b.p. 13 184. a, y-Dibenzyl- 
 indene C 6 H 4 : C 3 H 2 (CH 2 C 6 H 5 ) 2 , m.p. 63, by benzylating indene, also 
 by reduction of benzyl-benzylidene-indene, m.p. 137, with aluminium 
 amalgam (A. 347, 262). 1, 2, 3-Triphenyl-indene, m.p. 135 (C. 1908, 
 II. 1736). 1, 1, 3-Triphenyl-indene, m.p. 135 (B. 39, 1030). Bz.-amido- 
 jS-methyl-, -ethyl-, -iso-propyl-indene, m.p. 98, 89, 84. 
 
 j3-Nitro-indene C 6 H 4 : C 3 H 3 NO 2 , m.p. 141, yellow crystals, from 
 indene nitrosite by distillation with water vapour. Zinc dust and 
 glacial acetic acid reduce it to /Miydrindone-oxime (A. 336, i). 
 
646 ORGANIC CHEMISTRY 
 
 /Mndene-earboxylic acid C 6 H 4 C 3 H 3 COOH, m.p. 222-23o, from 
 hydrindene-carboxylic acid with bromine. y-Methyl-/Mndene-car- 
 boxylic acid, m.p. 200, from benzyl-aceto-acetic ester. 
 
 Indene-oxalic ethyl ester C 6 H 4 : C 3 H 3 .COCOOC 2 H 5 , m.p. 87, orange- 
 red needles, from indene-oxalic ester and sodium ethylate, gives, on 
 reduction with aluminium amalgam, indene-oxy-acetie ester C 6 H 4 : 
 C 3 H 3 .CH(OH)CO 2 C ? H 5 , b.p. 13 172, which, by saponification and 
 loss of water, gives benzo-fulvene-earboxylie acid C 6 H 4 : C 3 H 2 : 
 CHCO 2 H, decomposing at 175, orange flakes. The latter, on reduction, 
 yields indene-acetic acid C 6 H 4 : C 3 H 3 .CH 2 CO 2 H, m.p. 96, w^ich, on 
 further condensation, passes into benzo-fulvene-carboxylic acetic acid 
 C 6 H 4 : C 3 H(: CHCO 2 H)CH 2 CO 2 H, m.p. 245 with decomposition 
 (A. 347, 275). 
 
 j8, y-Dichloro-a-oxy-indene-carboxylic acid, melting at 100, is 
 obtained from j8-dichloro-naphtho-quinone. Chromic acid oxidises it 
 to dichlorindone. It is changed to chlorindone-carboxylic acid when 
 digested with concentrated sulphuric acid (B. 28, R. 279). 
 
 a, jS-Diphenyl-indone C 6 H 4 <(^^^C(C 6 H 5 ), garnet-red crystals, 
 
 melting at 151, is produced, together with triphenyl-acrylic acid, when 
 benzo-phenone chloride is condensed with phenyl-acetic ester. It 
 yields triphenyl-propane upon reduction. It is decomposed into 
 a, jS-diphenyl-vinyl-o-benzoic acid when fused with caustic potash. 
 It can be recovered from this as well as from triphenyl-acrylic acid on 
 heating with zinc chloride (B. 30, 1281). 
 
 j8-Phenyl-o-, m-, and p-nitro-indone 
 
 139, 205, and 2i5-2i7, from o-, m-, and p-nitro-phenyl-a-phenyl- 
 cinnamic acid (C. 1900, II. 1276). 
 
 Indone-^-acetic acid c 6 H 4 <^ CH yC.CH 2 co 2 H, m.p. 99, from phenyl- 
 
 itaconic acid with concentrated sulphuric acid, lemon-yellow prisms. 
 It is isomerised, by prolonged action of mineral acids, to saturated 
 colourless lactone, m.p. 123 (B. 41, 3983). Similarly we obtain 
 y-methyl-y-phenyl-indone-j3-aeetic acid and y-phenyl-indone-/2-pro- 
 pionic acid, m.p. 155, 167, and 168 respectively, from methyl-phenyl- 
 itaconic acid, diphenyl-itaconic acid, and a-methyl-yy-diphenyl-ita- 
 conic acid. 
 
 y-Bromindone C 6 H 4 : C 3 BrHO, m.p. 64, f$, y-diehloro- and dibromo- 
 indone C 6 H 4 : C 3 Br 2 O, m.p. 90 and 123, are obtained synthetically 
 from monobromo-dichloro- and dibromo-cinnamic acid (B. 32, 2477 ; 
 33, 2426). The jS-halogen atom is easily replaced by OH and NHR : 
 -ehloro- and j8-bromo-y-oxy-indone, m.p. 114 and 119 ; y-anilido- 
 indone, m.p. 105 with decomposition, is converted into diketo- 
 hydrindene by HC1. A halogen atom also easily reacts with Na-malonic 
 and acetic esters, etc., the resulting substances being feebly yellow, 
 but giving fine purple colours with alkalies, resembling cochineal 
 (B. 31, 2079, 2903 ; 33, 2418, 2425 ; 35, 2938). 
 
 Perchlorindone C 6 C1 4 : C 3 C1 2 O, m.p. 149, from a monocyclic 
 pentene derivative, hexachloroxy-cyclo-pentene-carboxylic acid, pro- 
 duced by the splitting of hexachloro-diketo-cyclo-hexene, by warming 
 with water, or sodium acetate solution (A. 367, i). 
 
INDENE AND HYDRINDENE GROUP 647 
 
 Hydrindene Derivatives. Hydrindene C 6 H 4 : C 3 H 6 is an oil, boiling 
 at 177. It results when indene is reduced with sodium and alcohol. 
 For other methods, see B. 33, 735 ; 34, 1247 ' C. 1903, II. 989. 
 
 Dichloro-hydrindene is an oil. Dibromo-hydrindene C 6 H 4 : C 3 H 4 Br 2 
 melts at 44. They yield ehlor- and bromoxy-hydrindenes, melting at 
 129 and 131, when digested with water. Ammonia converts the 
 latter bodies, in the cold, into amido-oxy-hydrindene, melting at 133, 
 which nitrous acid transposes into j8, y-dioxy-hydrindene, hydrindene- 
 glycol C 6 H 4 : C 3 H 4 (OH) 2 , melting at 99 (B. 26, 1539 ; 32, 30). 
 
 Hydrindene- jS-carboxylic acid C 6 H 4 (CH 2 ) 2 CH.CO 2 H, melting at 
 130, is converted by distillation of its salts into indene, by bromine 
 into indene-carboxylic acid, and is oxidised by KMnO 4 to o-carbo- 
 phenyl-glyoxylic acid. It results when CO 2 is eliminated from 
 hydrindene-/?-dicarboxylic acid, melting at 199. The ester of the 
 latter acid may be obtained synthetically from xylylene bromide and 
 malonic ester. 
 
 j8-Aeeto-hydrindene-carboxylic ester c a H 4 (CH 2 ) 2 c/^ c ^ 13 is obtained 
 
 from xylylene bromide and aceto-acetic ester. 
 
 y-Methyl-hydrindene-j3-carboxylic acid, m.p. 86; see C. 1906, 
 I. 1699. 
 
 Hydrindene-jS-methyl-, ethyl-, and phenyl-ketones are formed in 
 the distillation of hydrindene-carboxylic acid with benzoic acid, 
 propionic acid, and acetic acid (B. 26, 1539). 
 
 </->TJT v 
 ^ 2 ^>CH 2 , melting at 41 and boiling 
 
 at 244, is obtained in the dry distillation of o-carbohydro-cinnamic 
 acid as well as from o-cyan-hydro-cinnamic ester upon digesting with 
 concentrated hydrochloric acid. The phenyl-hydrazone melts at 131. 
 The oxime, melting at 146, is changed, by reduction, to a-amido- 
 hydrindene, hydrindamine, melting at 220. 
 
 The chlorohydrate decomposes almost quantitatively into AmCl 
 and indene, on heating. 
 
 N 2 O 3 converts it into a-oxy-hydrindene, melting at 54 (B. 26, R. 708). 
 Phosphorus pentachloride converts a-hydrindone-oxime into hydro- 
 carbo-styril (Beckmann's transposition) (B. 27, R. 598) : 
 
 /CH 2 x /CH 2 CH 8 
 
 CeH4 \C(NOH)/ C C ' H4 \NH-CO ' 
 
 Hydrindone-azine C 9 H 8 : N.N : C 9 H 8 , melting at 165, results from 
 the action of hydrazin upon the oxime. Nitrous acid converts 
 
 hydrindone into iso-nitroso-hydrindone C 6 H 4 <^^ 2 ^>C=NOH, melting 
 
 with decomposition at 210. This phenyl-hydrazin changes to a 
 osazone, melting at 229. The latter is isomeric with the dihydrazone 
 obtained from a, y-diketo-hydrindene. It yields /2-amido-a-hydrindone 
 when it is reduced (B. 29, 2605, R. 869 ; C. 1897, I. 860). 
 
 Concentrated H 2 SO 4 produces Beckmann's transposition, and forms 
 homo-phthalamidic acid (C. 1907, I. 727). With benzaldehyde (B. 34, 
 412) a-hydrindene gives a benzylidene compound C 9 H 6 O : CHC 6 H 5 , 
 yellow crystals, m.p. 114, also yielded by a-benzyl-cinnamic acid, with 
 concentrated sulphuric acid ; two molecules hydrindone condense to 
 
648 ORGANIC CHEMISTRY 
 
 anhydro-bis-hydrindone C 9 H 6 O : C 9 H 8 , m.p. 143, which, on further 
 condensation, gives the hydrocarbon tru%ene (C 9 H 6 )a. (C. 1894, II. 92 ; 
 B. 31, 720 ; 33, 3085 ; 36, 645). With o-phthal-aldehyde a-hydrindone 
 condenses to iso-naphtho-fluorenone C ? 6H * \co (A. 369, 288). 
 
 Ci H 6 / 
 
 When o-, m-, and p-methyl-hydro-cinnamic acids are heated they 
 yield o-, m-, and p-methyl-a-hydrindones. The constitution of the 
 latter is deduced from their oxidation to the various methyl-o-phthalic 
 acids. Bz.-Chloro-, bromo-, iodo-, and nitro-hydrindones behave 
 similarly (B. 25, 2095). 
 
 jS-Methyl-a-hydrindone, melting at 168 (n mm.), and jS-phenyl-a- 
 hydrindone, melting at 78, are obtained from a-methyl- and phenyl- 
 hydro-cinnamic acids. When its ethereal solution is shaken with 
 caustic soda jS-phenyl-hydrindone is changed partly to jS-phenyl-oxy- 
 hydrindone, melting at 129, and in part by rupture of the ring into 
 desoxy-benzoin-o-carboxylic acid C 6 H 4 (CO.OH).CH 2 .COC 6 H 5 (B. 26, 
 2095). y-Phenyl-a-hydrindone, melting at 78, is prepared from 
 j3, jS-diphenyl-propionic acid (B. 26, 2128). 
 
 j8j8-Dimethyl-a-hydrindone C6H 4 < 2 > C (CH 3 ) 2 , m>p . ^ from 
 
 aa-dimethyl-jS-phenyl-propionic acid chloride and A1C1 3 , or by methy- 
 lation of a-hydrindone by means of NaNH 2 and CH 3 L On heating 
 with NaNH 2 in benzene solution, it is split into the amide of aa-dimethyl- 
 j3-phenyl-propionic acid. j3/?-Diethyl-a-hydrindone, m.p. 7, b.p. 13 
 138 (C. 1910, II. 39). 
 
 Tetrachloro-a-hydrindone CgH 4 : C 3 C1 4 O, melting at 108, is the addi- 
 tion product of chlorine and dichlorindone. It is readily decomposed 
 by digestion with alcoholic sodium hydrate into o-trichloro-vinyl- 
 benzoic acid. Chloro-dibromo-hydrindone-y-earboxylic acid C 6 H 4 : 
 [C 3 ClBr 2 O(COOH)], melting at 171, is made from chlorindone-y-car- 
 boxylic acid and bromine. It is similarly decomposed into bromo- 
 chloro-methylene-homo-phthalic acid. 
 
 /?-Nitro-a-hydrindone C 6 H 4 <^*^>CH .NO 2 , sulphur-yellow needles, 
 
 m.p. 117 with decomposition, is formed by condensation of o-phthal- 
 aldehyde with nitro-methane and sodium ethylate (A. 377, 15). 
 
 j8-Hydrindone, fi-indanone C 6 H 4 (CH 2 ) 2 CO, m.p. 61, b.p. 220-225 
 with decomposition, is formed by the distillation of calcium o-phenylene 
 diacetate, and by heating hydrindene-glycol, or its monomethyl ether, 
 with sulphuric acid. Hydrazone, m.p. 120. Oxime, m.p. 155, gives, 
 by reduction, j8-amido-hydrindene (B. 26, R. 709). Di-iso-nitroso-j8- 
 hydrindone C 6 H 4 [C(NOH)] 2 CO 2 , m.p. 233 with decomposition. Like 
 the a-hydrindone and the diketo-hydrindene, the j3-hydrindone easily 
 condenses to anhydro-bis-j8-hydrindone C 9 H 6 : C 9 H 8 , m.p. 170 
 (B. 32, 28). 
 
 Tetrachloro-jS-hydrindone C 6 H 4 : C 3 C1 4 O, m.p. 98, is formed by the 
 action of bleaching - lime upon tetrachloro-2, 3-diketo-tetrahydro- 
 naphthalin. Monobromo-, a, y-dibromo-, and tetrabromo-hydrindone, 
 m.p. 91, in , and 173, by bromination of j8-hydrindone in benzene 
 solution. Tetrachloro- and tetrabromo-hydrindone on heating with 
 alkalies pass into phthalide-carboxylic acid (benzilic acid transposition) 
 (A. 334, 346 ; C. 1908, II. 1183). 
 
INDENE AND HYDRINDENE GROUP 649 
 
 jS-Acetyl- and jS-benzoyl-a-hydrindone, m.p. 76 and 98 (A. 347, 
 112) ; a-hydrindone-/3-oxalie acid, m.p. 212 (A. 369, 287). 
 
 a.y-Diketo-hydrindene C 6 H 4 (CO) 2 CH 2 , melting with decomposition 
 at 130, is obtained from its carboxylic acid (below). It consists of 
 colourless needles, which dissolve readily with a yellow colour in alkalies. 
 The hydrogen atoms of the methylene groups placed between the two 
 keto-groups have an acid nature. Phenyl-hydrazin converts it into 
 a monohydrazone, melting at 163, and a dihydrazone C 6 H 4 (C : NNH 
 C 6 H 5 ) 2 CH 2 , melting at 171. Diazo-benzene chloride converts the 
 monohydrazone into a triketo-hydrindene C 6 H 4 (CO) 2 C : NNHC 6 H 5 , 
 which is also prepared by the decomposition of benzal-diketo-hydrindene 
 C 6 H 4 (CO) 2 C=CHC 6 H 5 , a condensation product of benzaldehyde and 
 diketo-hydrindene, with phenyl-hydrazin. 
 
 3, 4-Dioxy-benzal-diketo-hydrindene, melting at 257, and prepared 
 by the condensation of proto-catechuic aldehyde and diketo-hydrindene, 
 is a dye (B. 30, 1185). 
 
 With p-amido-benzaldehydes, also, feebly basic dyes are obtained. 
 o-Amido-benzaldehyde yields the so-called quinolene-phenylene- 
 ketone c.H 4 { WH= }c 6 H 4 , m.p. 175 (B. 34, 2467). 
 
 With orthoformic ester, indane-dione condenses to the compounds 
 C 6 H 4 (CO) 2 C : CHOH and C 6 H 4 (CO 2 )C : CH.CH(CO 2 )C 6 H. With am- 
 
 monia we obtain from this dibenzoylene-pyridin 
 
 (C. 1903, II. 950). With ethoxy-methylene-aceto-acetic ester (Vol. I.), 
 indane-dione forms indane-dione-methenyl-aceto-acetic ester, m.p. 118, 
 which is condensed by concentrated alkali to 3-oxy-diphenylene- 
 ketone-2-carboxylie acid (C. 1906, I. 849). By heating diketo-hydrin- 
 dene by itself or boiling with water, anhydro-bis-diketo-hydrindene- 
 bindone C 6 H 4 (CO) 2 C=C<^^ 4 ^>CO is formed, yielding intensely coloured 
 
 metallic compounds. Heated with aromatic amines, it gives, like 
 coerulignone, beautiful blue dyes (B. 30, 3137). Phenyl-hydrazin 
 splits it into two molecules diketo-hydrindene-dihydrazone (A. 277, 362 ; 
 B. 34, 3269). The anhydro-bis-diketo-hydrindene can undergo higher 
 condensation (B. 31, 2935 ; 33, 2433). 
 
 jS-Methyl-diketo-hydrindene C 6 H 4 (CO) 2 CHCH 3 , m.p. 85, is formed 
 from its carboxylic acid. Its sodium compound gives, with methyl 
 iodide, ^-dimethyl-diketo-hydrindene C 6 H 4 (CO 2 )C(CH 3 ) 2 . -Phenyl- 
 diketo-hydrindene, m.p. 145, from benzal-phthalide. The isatin- 
 diphthalyl, m.p. above 350, violet needles, similarly obtained by trans- 
 position of ethine-diphthalyl, is now regarded as derived from a hydro- 
 carbon, naphthacene C 16 H 12 compound of two naphthalene nuclei, and 
 
 has the structure C.H 4 < : -^^ (R 31> I2?2) ^ - D iethyl- 
 
 diketo-hydrindone C 6 H 4 (CO) 2 C(C 2 H 5 ) 2 , b.p. 10 i43-i56, oxime, m.p. 
 143, from benzene, diethyl-malonyl chloride, and A1C1 3 (A. 373, 291). 
 
 jS-Diehloro-diketo-hydrindene C 6 H 4 (CO) 2 CC1 2 , m.p. 125, by the 
 action of chlorine upon y-oxy-chlorindone. It is split up into o-phthalic 
 acid by dilute soda (B. 21, 491, 2380). 
 
 -Bromo-diketo-hydrmdene C 6 H 4 (CO) 2 CHBr is identical with 0- 
 bromo-y-oxy-indone and is formed also from diketo-hydrindene-car- 
 boxylic ester by bromination and saponification. Boiling with water 
 
650 ORGANIC CHEMISTRY 
 
 gives dibromo-diketo-hydrindene C 6 H 4 (CO) 2 CBr 2 and finally tris-diketo- 
 hydrindene C 6 H 4 (CO) 2 C[CH(CO) 2 C 6 H 4 ] 2 ; see also B. 33, 2433; 34, 
 
 2145- 
 
 Diketo-hydrindene-earboxylic ester C 6 H 4 (CO) 2 CH.COOR, m.p. 75- 
 78, from phthalic ester with acetic ester and Na alcoholate, is easily 
 converted into diketo-hydrindene. Other derivatives, see B. 31, 2084 ; 
 M. 31, 62. 
 
 /?-Acetyl and jS-benzoyl-diketo-hydrindene C 6 H 4 (CO) 2 CH.COR, m.p. 
 110 and 108, from phthalic ester with acetone and aceto-phenone. 
 Easily split up by. alkalies (B. 27, 104). 
 
 Indacene is the name of a tricyclic combination of a benzene nucleus 
 with two cyclo-pentene nuclei. From m-xylylene-diaceto-acetic ester, 
 with 80 per cent. H 2 SO 4 , we obtain dimethyl-indacene-carboxylic acid 
 
 C0 2 Hc(^ H3) Nc 6 H 2 /^ H ^")cco 2 H; from pyro-mellithic ester, acetic 
 
 XUrig - / XGHg - 
 
 ester, and Na tetraketo-hydrindacene-dicarboxylic ester CO 2 RCH(CO) 2 
 C 6 H 2 .(CO) 2 CHCOOR (B. 34, 2779). 
 
 Fluorene is a dibenzo-pentene resulting from the union of the pentene 
 nucleus with two benzene nuclei. It will be considered in conjunction 
 with chrysene-fluorene and picene-fluorene after the condensed nuclei 
 of the phenanthrene group phenanthrene, chrysene, and picene, to 
 which the two first-named bodies are intimately related. 
 
 II. NAPHTHALENE GROUP. 
 
 Garden (1816) discovered naphthalene C 10 H 8 , among the distillation 
 products of coal-tar. It shows great similarity to benzene, from which 
 it differs in constitution by C 4 H 2 . Like benzene, it is produced by the 
 action of intense heat upon various carbon compounds ; hence its 
 occurrence in coal-tar. Numerous derivatives are obtained from it by 
 the replacement of its hydrogen atoms ; they are very similar to the 
 benzene compounds. Only the most important of them will be con- 
 sidered in the following sections. 
 
 Constitution of the Naphthalene Nucleus. 
 
 The behaviour of naphthalene is satisfactorily explained by the 
 formula first suggested by Erlenmeyer, sen. (A. 137, 346) : 
 
 H H 
 
 YYY 
 
 H H 
 
 It consists of two benzene nuclei, having in common two carbon 
 atoms occupying the ortho-position. Graebe (1866) proved the correct- 
 ness of the formula (A. 149, 20). 
 
 The oxidation of napthalene to o-phthalic acid shows the presence 
 of a benzene nucleus. Further, the oxidation of dichloro-naphtho- 
 quinone C 6 H 4 : C 4 C1 2 O 2 also yields o-phthalic acid. If, however, di- 
 chloro-naptho-quinone is converted by PC1 5 into tetrachloro-naphtha- 
 lene, this, upon oxidation, will become tetrachlor-o-phthalic acid. In the 
 second instance, therefore, the benzene nucleus, which in the first case 
 was unattacked, is now oxidised. A precisely similar method of de- 
 
NAPHTHALENE GROUP 651 
 
 monstration, to which reference has already been made, is as follows : 
 Nitro-naphthalene, obtained by nitration of naphthalene, yields nitro- 
 o-phthalic acid ; whereas amido-naphthalene, resulting from the re- 
 duction of the preceding nitro-naphthalene, yields o-phthalic acid : 
 
 NH 2 NO 2 NO 2 
 
 "i_i /x ri___i / Y ooH 
 
 Hence it follows that naphthalene must consist of two symmetri- 
 cally condensed benzene nuclei. For other formulae, like the central 
 formula of Bamberger, the formula of Armstrong, etc., consult B. 23, 
 R. 337, 692 ; 24, R. 651, 728 : 
 
 i\ y /i 
 I/ -L \l 
 V \\/\\/ 
 
 Bamberger. Armstrong. 
 
 Isomerisms of the Naphthalene Derivatives. The isomerisms of the 
 derivatives of naphthalene conditioned by this formula agree with the 
 facts. The substituents are designated according to the diagram : 
 
 
 
 a 4 a, 
 
 f 
 
 The replacement of an H atom in naphthalene can give rise to two 
 isomeric mono-derivatives, distinguished as a- and fl-derivatives accord- 
 
 \C/ 
 ing as the substituent is adjacent to the complex || common to 
 
 both groups, or separated from it by a CH group. The positions i, 4, 5, 
 8 (a lf a 2 , a 3 , a 4 ) on the one side, and 2, 3, 6, 7 (fa, j3 2 , 3 , j3 4 ) are equi- 
 valent. Liebermann (A. 183, 254) and Atterberg (B. 9, 1736) have 
 adduced proof of the equivalence of the four a-positions. The method 
 adopted is similar to that followed in demonstrating the equal value 
 of the benzene hydrogen atoms. 
 
 Whether a substituent occupies the a- or j3-position is mainly de- 
 termined by its oxidation to a corresponding o-phthalic acid derivative. 
 Thus, if [i, 2, 3]-nitro-phthalic acid is obtained from a-nitro-phthalene, 
 the nitro-group must consequently be adjacent to the contact position 
 of the second benzene nucleus in naphthalene. The constitution of a- 
 oxy-naphthalene or a-naphthol is evident also from its synthesis by 
 means of phenyl-iso-crotonic acid C 6 H 5 .CH : CH.CH 2 .COOH. Be- 
 sides, only a-derivatives of naphthalene can be converted into quinones 
 analogous to p-benzo-quinone, as these alone possess a free H atom in 
 para-position with reference to the substituent. This latter circum- 
 stance also determines still other peculiarities in the behaviour of the 
 compounds of naphthalene e.g. the power of the naphthols and 
 naphthylamines to unite with diazo-bodies, etc. 
 
 The di-substitution products of naphthalene, when the substituents 
 are similar, can exist in ten isomeric forms, which are designated by 
 numbers or prepositions (B. 26, R. 533). In the following diagram the 
 
652 ORGANIC CHEMISTRY 
 
 double hexagon of naphthalin is replaced by two parallel lines, as 
 was similarly done with benzene : 
 
 R R R R R R RR 
 
 1,2 1,3 1,4 1,5 1,6 1,7 1,8 2,3 2,6 2,7 
 
 Ortho- Meta- Para- Ana- Epi- Kata- Peri- Amphi- Pros- 
 
 On the calculation of the isomeric possibilities of the naphthalin 
 derivatives, see B. 33, 2131. 
 
 The position of the substituents in the di-derivatives can very often 
 be determined by the oxidation method, if thereby it can first be ascer- 
 tained whether the substituents are in the same nucleus (isonuclear) 
 or in different nuclei (heteronuclear) . Isonuclear substitution products 
 with adjacent substituents, show in general the same behaviour as 
 the ortho-substitution products of benzene, inasmuch as they form 
 similar condensation products. However, a difference appears to exist 
 between positions like I, 2 and 2, 3. Thus, only those amido-naph- 
 thalenes manifest the ability to form naphtho-quinolin rings, in which 
 the pyridene ring can attach itself to a, ft- C atoms. It must be 
 assumed that the double linkages in naphthalene are not so easily dis- 
 placed as in benzene. The behaviour of the I, 8- or peri-derivatives is 
 remarkable. Like the o-di-derivatives, they exhibit a series of hetero- 
 ring formations. 
 
 Naphthalene-ring Formations. 
 
 Naphthalene is produced by pyrogenic condensation from a series 
 of carbon compounds, like ethylene, acetylene, ether, etc. Methods of 
 producing the naphthalene nucleus by processes in which one benzene 
 nucleus pre-exists are more important : 
 
 1. A mixture of benzene and acetylene conducted through a tube 
 heated to redness yields naphthalene (Bull. 7, 306). 
 
 2. It is derived from phenyl-butylene C 6 H 5 .CH 2 .CH 2 .CH : CH 2 
 and its dibromide, on leading their vapours over heated lime : 
 
 /CH 2 CH 2 /CH=CH 
 
 C 6 H/ | = C 6 H 4 < | + 4 H. 
 
 CH 2 =CH \CH-CH 
 
 Similar reactions result in the formation of phenyl-dihydro-naphthoic 
 acid from dibenzal-propionic acid with glacial acetic-sulphuric acid ; 
 of phenyl-bromo-tetrahydro-naphthoic acid from benzyl-phenyl-iso- 
 crotonic acid with Br ; and of i-phenyl-tribromo-naphthalene by the 
 bromination of diphenyl-diacetylene (A. 341, 198). 
 
 3. Phenyl-propiolic acid, on heating with acetic anhydride or treat- 
 ing with POC1 3 , passes into the anhydride, while phenyl-propiolic ester, 
 on heating to 200, forms the ester of i-phenyl-naphthalene-2, 3-dicar- 
 boxylic acid. This anhydride is also formed by illumination of dibenzal- 
 succinic anhydride in benzene solution : 
 
 /C=CH.COOH ,CH=C.CO C G H 5 CH : C.CCX 
 
 C 6 H/ - > C 8 H 4 < > < -- >0. 
 
 C=CH.COOH \C=C.CO/ C 6 H 5 CH : C.CCX 
 
 C 6 H 5 C 6 H 5 
 
NAPHTHALENE GROUP 653 
 
 4. Xylylene bromide and sodium-acetylene-tetracarboxylic ester pro- 
 duce tetrahydro-naphthalene-tetracarboxylic ester, which, on saponi- 
 fication, yields tetrahydro-naphthalene-dicarboxylic acid, whose silver 
 salt passes by distillation into naphthalene (Baeyer and Perkin, B. 17, 
 488 ; cp. formation of the tetramethylene and indene rings) : 
 
 /CH 2 Br NaC(CO,R) 2 / 2 
 
 C.H 4 / +1 = C 6 H 4 < 
 
 x CH 2 Br NaC(CO 2 R) 2 X:H 2 C(CO 2 R) 2 
 
 5. o-Xylylene cyanide condenses in the presence of Na ethylate 
 with oxalic ester and a-diketones to form naphthalene derivatives 
 (B. 43, 1300) : 
 
 /CH 2 CN , ROCO _ /C(CN) : COH 
 
 ^^ \CH 2 CN ROCO 6 4 \C(CN) : COH 
 
 /CH 2 CN , OCR _ /C(CN) : CR 
 
 C ' 4 \CH 2 CN "'"OCR 6 4 \C(CN) : CR' 
 
 6. What is further noteworthy is the formation of a-naphthol from 
 phenyl-iso-crotonic acid when heated (Fittig and Erdmann, B. 16, 43 ; 
 A. 247, 372 ; 255, 263 ; 275, 284 ; cp. formation of indene deriva- 
 
 tives) : 
 
 CH 
 
 /CH= 
 C 8 H/ = C 6 H 4 < +H 2 0. 
 
 OC(OH) CH 2 X C(OH)=CH 
 
 Phenyl-iso-crotonic acid a-Naphthol. 
 
 In a perfectly similar manner 5-, 6-, and f j-chloro-i-naphthols are obtained 
 from o-, m-, and p-chloro-phenyl-paraconic acids', 2-and ^-methyl-naphthols 
 from a- and ^-methyl-par aconic acids ; a-naphthol-3-methyl-ketone 
 
 (B. 26, 345) from B-benzal-lfevulinic acid C 6 H/ 
 
 OC(OH) - CH 2 
 and 2-phenyl-i, 3-dioxy-naphthalene is produced when a, y-diphenyl- 
 
 CH 2 - CO 
 aceto-acetic ester C 9 U/ is digested with concen- 
 
 ROCO CH(C 6 H 5 ) 
 trated sulphuric acid (A. 296, 14). 
 
 Similarly, phenacetyl-malonic ester gives I, 3-dioxy-naphthalene- 
 2-carboxylic ester (A. 298, 374), and cinnamylidene-hippuric acid, 
 or its decomposition product, cinnamyl - pyro - racemic acid, gives 
 
 /pTT _ /->TT J 
 
 C ' Hs COIC^.CH, - na P hthoi c acid (B. 35, 384)- 
 
 7. y-Phenyl-f$-imino-butyro-nitrile condenses under the action of 
 concentrated H 2 SO 4 to i, 3-diamido-naphthalene (C. 1909 I, 857) : 
 
 /CH 2 C : NH /CH=C.NH 2 
 
 C 6 H/ - > C 6 H 4 < 
 
 CN CH 2 N:(NH a ) : CH 
 
 Similarly, we get from y-phenyl-y-imino-a-cyano-butyric ester 
 
 C.H ; 'Vr o the i. 4-diamido-naphthalene-2-carboxylic ester, 
 
 - 
 
 and, from the imino-nitriles obtained by the condensation of o-tolu- 
 
 7 C( : NH).CHC 6 H 5 
 nitrile with benzyl cyanide or cyano-acetic ester C 6 U^<f I 
 
 x)H CN 
 
 and C 6 H 4 < - 2j the ^ 3 .diamido-2-phenyl-napthalin and 
 
654 ORGANIC CHEMISTRY 
 
 i, 3-diamido-naphthalin-2-carboxylic ester respectively (C. 1907, I. 
 728 ; II. 68, 539, 2053). 
 
 8. An interesting formation of a-naphthylamine consists in heating 
 aniline with pyro-mucic acid and zinc chloride to 300 (B. 20, R. 221) : 
 C0 2 H.C=^CH X CH=CH 
 
 Aniline Pyro-mucic acid a-Naphthylamine. 
 
 a-Naphthylamine is similarly formed on heating aniline hydro- 
 chloride with mannitol under pressure. 
 
 9. Two molecules of styrolene alcohol or phenyl-glycol can be con- 
 densed by dilute H 2 SO 4 to jS-phenyl-naphthalene (A. 240, 137) : 
 
 / CH(OH).CH 2 (OH) 
 + 
 CH 2 (OH) CH(OH)C 6 H 
 
 C.H/ + = C 6 H 4 < | + 4 H 2 0. 
 
 X CH C.C 6 H 5 
 
 Phenyl-acetaldehyde is an intermediate product. 
 
 10. The formation of a naphthalene derivative in the oxidation 
 of bromo-proto-catechuic acid with nitric acid is peculiar. There is 
 produced thereby a dibromo-j3-naphtho-quinone-carboxylic acid 
 (A. 293, 120) : 
 
 CO CO 
 
 2COOH.C 6 H 2 Br(OH), > COOH.C 6 H 2 Br< 
 
 x CH=CBr. 
 
 Decompositions of the Naphthalene Ring. 
 
 Naphthalene and most of its derivatives are converted by energetic 
 oxidants into o-phthalic acid and substituted o-phthalic acids with de- 
 struction of one benzene nucleus. The oxidation is made easier by the 
 introduction of an amido-group into the nucleus which is to be oxidised. 
 Naphthols and their derivatives are decomposed by heating with 
 alkalies, and oxidising metallic oxides to form phthalic and benzoic 
 acids (C. 1903, I. 1106). 
 
 In many instances it has been possible, by moderating the oxidising 
 action, to arrest the intermediate products of this reaction, or even the 
 primary products in the breaking-down of the ring. 
 
 i. Decomposition by Mild Oxidation. (a) Potassium permanganate 
 oxidises naphthalene to phthalic acid and phenyl-glyoxyl-o-carboxylic 
 acid (B. 28, R. 490) : 
 
 /CH^CH /CO.COOH 
 
 C 6 H 4 <( | > C 6 H 4 < 
 
 X CH=CH X COOH 
 
 Naphthalene Phenyl-glyoxyl-o-carboxylic acid. 
 
 (b) a- and j8-Naphthols, oxidised with an alkaline permanganate 
 solution, also yield o-carbo-phenyl-glyoxylic acid. /S-Naphthol with 
 most careful oxidation becomes o-cinnamo-carboxylic acid, along with 
 other products (M. 10. 115). 
 
 Besides these reactions we have the decomposition of sodium-nitroso- 
 j8-naphthol by heating to 250, forming o-cyano-cinnamic acid : 
 
 rw /CH=COH _^ r u /COOHCOOH r / C(NO).CONa ^^u/CN COONa 
 
 C 'McH=CH " " C ' H 'toH=CH ;CaH MCH = CH ^ QH McH=CH 
 
 /3-Naphthol o-Cinnamo-carboxylic Nitroso-/3-naphthol o-Cyano-cinnamic acid, 
 acid. 
 
NAPHTHALENE GROUP 655 
 
 In the oxidation of a-nitro-naphthalene with potassium perman- 
 ganate products appear which, in the process of reduction, yield, among 
 other things, isatin-carboxylic acid NH 2 [3]C 6 H 3 { ^^ OH (B. 28, 
 
 1641). Naphthalic acid becomes phenyl-glyoxyl-dicarboxylic acid. 
 
 (c) The decomposition of hydrogenised naphthalene derivatives 
 occurs with special readiness ; thus, permanganate changes dihydro- 
 /3-naphthol into dihydro-iso-cumarin-carboxylic acid, while potassium 
 bichromate oxidises tetrahydro-naphthylene-glycol, in the cold, to 
 phenylene-o-diacetic acid (B. 26, 1833) : 
 
 CH 2 CHOH /CH 2 CH 
 
 2 CHOH /C 
 
 - > C.H/ 
 =CH X C 
 
 OO COOH 
 Dihydro-jS-naphthol Dihydro-iso-cumarin-carboxylic acid. 
 
 CH 2 CHOH /CH 2 .COOH 
 
 | - * C 6 H 4 < 
 
 H 2 CHOH X CH 2 .COOH 
 
 Tetrahydro-naphthylene-glycol o-Phenylene-diacetic acid. 
 
 Potassium permanganate oxidises ac-tetrahydro-naphthylamine to 
 o-hydro-cinnamo-carboxylic acid ; ar-tetrahydro-naphthylamine, how- 
 ever, because of the oxidation of its amided benzene nucleus, is changed 
 to adipic acid together with oxalic acid (B. 22, 767) : 
 
 ,CH(NH 2 ) CH, /COOH COOH 
 
 r TT / V 2 ' I 2 _ ^ r TT / | 
 
 C 6 HX - > C 6 H 4 < 
 
 \CH 2 - CH 2 X CH 2 - CH 2 
 
 ac-Tetrahydro-naphthylamine o-Carbohydro-cinnamic acid. 
 
 /CH 2 CH 2 HOOC HOOC.CH 2 CH 2 
 
 NH 2 .C 6 H 3 <( | - > 1 + 
 
 X CH 2 CH 2 HOOt HOOC.CH 2 CH 2 
 
 ar-Tetrahydro-naphthylamine Oxalic acid Adipic acid. 
 
 2. Decomposition by Simultaneous Chlorination and Oxidation. 
 The ring-decompositions, produced by the action of chlorine or hypo- 
 chlorous acid upon jS-naphtho-quinone and its derivatives, are very 
 numerous. They proceed on lines analogous to the benzene-ring de- 
 compositions. Two groups may be distinguished in these changes : 
 either the naphthalene ring first resolves itself into an indene ring, 
 which subsequently by decomposition is converted into o-di-derivatives 
 of benzene, as in the case of dichloro-naphtho-quinone (see below), or the 
 break-down proceeds without the intermediate formation of indene, 
 as in the case of j3-naphtho-quinone or nitro-j3-naphtho-quinone (see 
 below) (Zincke, B. 27, 2753, etc.). Examples: (a) j8-Naphtho-quinone, 
 by the action of hypochlorous acid, becomes dioxy-diketo-tetrahydro- 
 naphthalene, which by the decomposition of the ring changes to the 
 lactone of o-phenyl-glycerol-carboxylic acid (B. 25, 3599) : 
 
 CO ,COO COOH 
 
 , - ,^ 
 
 C 6 H 4 < I * C 6 H 4 < \| 
 
 X CHOH CHOH X CHOH CH 
 
 /9-Naphtho-quinone Dioxy-diketo-tetrahydro- o-Phenyl-glycerol-car- 
 
 naphthalene boxylic acid lactone. 
 
 (b) With chlorine, nitro-j3-naphtho-quinone first forms a chlorine 
 addition product, which by ring-decomposition readily passes into 
 
656 ORGANIC CHEMISTRY 
 
 o- (a, j8-dichloro-nitro-ethyl) -benzoyl-f ormic acid . Chromic acid oxidises 
 the latter, with loss of hydrochloric acid and carbon dioxide, to nitro- 
 chloro-methyl-phthalide, which can be directly formed by treating nitro- 
 quinone with chlorine and water (B. 25, R. 732) : 
 
 co co xo co .CO.COOH / co ">o 
 
 C " H X;H=C.No7~~"" * XJHCLCONQJ ' *\CHC1.CHC1N0 2 *\CH CHC1NO, 
 
 Nitro-/3-naphtho- Chlorine addition o-(a, /3-Dichloro-nitro-ethyl)- Nitro-chloro-methyl- 
 
 quinone product' benzoyl-f ormic acid' phthalide. 
 
 (c) Alkalies rearrange 3, 4-dichloro-j3-naphtho-quinone to dichloroxy- 
 indene-carboxylic acid. The latter can be decomposed (i) by changing 
 it to dichlorindone with CrO 3 , and tetrachloro-hydrindone, the chlorine 
 addition product, when acted upon with alcoholic soda, becomes o-tri- 
 chloro-vinyl-benzoic acid ; or (2) if the acid be heated to ioo-iio with 
 oil of vitriol it is converted into j3-chlorindone-y-carboxylic acid. The 
 bromine addition product of the latter acid is decomposed by alkalies 
 with the formation of a-chloro-bromo-methylene-homo-phthalic acid 
 (B. 28, R. 279) : 
 
 /CO. CO i /C0\ /CO \ /COOH 
 
 p TT / k r* TT / \/~>n ^ C* IT / X/~*^1 ^ r 1J S 
 
 *\CC1:CC1 
 Dichloro-naph- 
 tho-quiiione 
 
 C(OH).CO a H 
 
 C 6 H 4 
 
 CeH 4 < 
 
 \CC1=CC1 2 
 Dichlorindone Tetra-chloro-hy- o-Trichloro-vinyl- 
 
 drindone benzoic acid 
 
 2 
 
 'C.COOH /CBr COOH 
 
 ./COOH 
 
 C 8 H 
 
 4 \CO/ C - C1 4 \CO/> CBrC1 \COOH 
 
 Dichlor-oxy-indene j8-Chlorindone- Dibromo-chloro-a-hydrin- Bromo-chloro-methylene- 
 
 carboxylic acid y-carboxylic acid done-y-carboxylic acid homo-phthalic acid. 
 
 (d) 2, 3-Dioxy-naphthalin (i) yields under the action of chlorine 
 tetrachloro-2, 3-diketo-tetrahydro-naphthalin (2), which is converted 
 by bleaching-lime into tetrachloro-/3-hydrindone (3) ; the latter is split 
 up by alkalies to phthalide-carboxylic acid (4), and by concentrated 
 HNO 3 to phthalonic acid (5) (A. 334, 342) : 
 
 (i) (2) (3) (4) - - / CH -^ 2H 
 
 /CH : coH__ r 2 H /cci t .co_^ r _ w yca, 
 
 /CO.COOH 
 
 3. A transformation of the naphthalin nucleus into the indene 
 nucleus has also been effected by the liquid nitrous acid upon a-naphtho- 
 quinone ; this first forms diketo-hydrindene-nitrosite, which, on careful 
 treatment with water, passes into a, y-diketo-hydrindene (B. 33, 543) : 
 
 CO CH 
 
 4. When perchloro-naphthalene is heated with SbCl 5 to 28o-3oo 
 it is resolved into perchloro-benzene, tetrachloro-methane, and hexa- 
 chloro-ethane (B. 9, 1486) : 
 
 6 - 
 
 1 \CC1=CC1 CC1 4 
 
 Perchloro-naphthalene. 
 
 5. Decomposition by Reduction in Alkaline Solution. A ring-de 
 composition analogous of that of salicylic acid (p. 49) is that under 
 
NAPHTHALENE GROUP 657 
 
 gone by 2, i- and 2, 3-oxy-naphthoic acids (p. 679) when their alcoholic 
 solutions are acted upon by metallic sodium (A. 286, 268) : 
 
 /C(COOH) : COH CH 2 .COOH OH.C=CH, 
 
 C 6 H 4 <( ->C 6 H 4 / COOH- >C 6 H 4 
 
 \CH =.CH COOH.C=CH/ 
 
 CH 2 - CH 2 
 
 2-Oxy-i-naphthoic acid o-Phenylene-aceto-propionic 2-Oxy-3-naphthoic acid. 
 
 acid 
 
 6. Naphthalene-disulphonic acids, naphthylamine- and naphthol- 
 sulphonic acids, containing the substituents in the I, 3-position, sustain 
 a remarkable decomposition into o-toluic acid when they are fused with 
 caustic potash (B. 28, R. 364) : 
 
 / C(S0 3 H):CH CH 
 
 C6H4 \CH=C(S0 3 H) 
 
 Naphthalene-i-3- disulphonic acid o-Toluic acid. 
 
 m-Cresol (Ch. Z. 1895, No. 48) is similarly produced on fusing i, 3, 6- 
 and 1,3, 8-naphthalene-trisulphonic acids with caustic potash. 
 
 Naphthalene C 10 H 8 , melting at 79 and boiling at 218, occurs in coal- 
 tar, and is obtained by crystallisation from that portion boiling from 
 i8o-3OO. It is purified by distillation with steam and sublimation. 
 It dissolves with difficulty in cold alcohol, readily in hot alcohol and in 
 ether. It crystallises and sublimes in shining plates. It is charac- 
 terised by its great volatility and possesses a peculiar odour. It forms 
 a crystalline compound C 10 H 8 .C 6 H 2 (NO 2 ) 3 .OH with picric acid, which 
 melts at 149 (Fritzsche, J. 1857, 456). m- and p-Dinitro-benzene, tri- 
 nitro-benzene, trinitro-toluene, etc., form similar double compounds. 
 
 Naphthalene is applied technically in the preparation of phthalic 
 acid and dye-substances. It is also used in carburetting water-gas. It 
 is employed for itch, moths, etc., because of its strong antiseptic pro- 
 perties and its stupefying effect upon the lower animals. 
 
 As naphthalene has unsaturated linkages it will, under favourable 
 conditions, take up hydrogen and chlorine ; the compounds thus pro- 
 duced will be discussed in conjunction with other hydro-naphthalene 
 derivatives at the conclusion of the naphthalene group. Naphthalene, 
 like benzene, is chlorinated, nitrated, and sulphonated by halogen, 
 nitric acid, and sulphuric acid. 
 
 Naphthalene Homologues. The methylated naphthalenes are pre- 
 sent in coal-tar. Alkylic naphthalenes also result from the bromo- 
 naphthalenes by the action of alkylogens and sodium, and from naph- 
 thalene by means of alkyl iodides or bromides and A1C1 3 : 
 
 M.p. B.p. 
 
 a-Methyl-naphthalin . 
 
 C 10 H 7 -a-CH 3 
 
 . -20 
 
 2 4 0-243 
 
 ^-Methyl-naphthalin . 
 
 C 10 H 7 --CH 3 
 
 +32-5 
 
 24I-242 01 
 
 i, 4-Dimethyl-naphthalin 
 
 C 10 H 6 -i, 4 -(CH 3 ) 2 
 
 liquid 
 
 262-264 2 
 
 a-Ethyl-naphthalin 
 
 C 10 H 7 -a-C 2 H 5 
 
 
 
 258 
 
 /8-Ethyl-naphthalin . 
 
 C 10 H V^- C 2 H 5 
 
 . -19 
 
 251 
 
 a-n-Propyl-naphthalin . 
 
 C 10 H 7 -a-(CH 2 ) 2 CH 3 
 
 liquid 
 
 274 
 
 j3-n-Propyl-naphthalin . 
 
 C 10 H 7 -0-(CH 2 ) 2 CH 3 
 
 ,, 
 
 278 
 
 ct-n-Butyl-naphthalin 
 
 C 10 H 7 -a-(CH 2 ) 3 CH 3 
 
 ,, 
 
 282 
 
 /?-n-Butyl-naphthalin 
 
 C 10 H 7 --(CH 2 ) 3 CH 3 
 
 
 
 284 
 
 1 B. 25, R. 857. 2 B. 28, R. 619. 
 VOL. II. 2 U 
 
658 ORGANIC CHEMISTRY 
 
 M.p. B.p. 
 
 uid 
 
 a-Iso-butyl-naphthalin C 10 H 7 -a-CH 2 CH(CH 3 ) 2 . liquid 137 (n mm.) 
 
 /S-Iso-butyl-naphthalin C 10 H 7 -/3-CH 2 CH(CH 3 ) 2 112 ( 6 mm.) 
 
 a-Phenyl-naphthalin . C 10 H 7 -a-C 6 H 5 . o 325 
 
 0-Phenyl-naphthalin . C 10 H 7 -/5-C 6 H 5 . 102 347. 
 
 a- and j3-Phenyl-naphthalenes have been prepared by the action 
 of diazo-benzene chloride upon naphthalene in the presence of A1 2 C1 6 . 
 
 Similarly, nitro-phenyl-naphthalene, melting at 129, is obtained from 
 sodium nitro-phenyl-nitrosamine with naphthalene (B. 29, 168). 
 
 j3-Phenyl-naphthalene is also formed on conducting the vapours of 
 bromo-benzene and naphthalene through tubes heated to redness ; also 
 in the condensation of two molecules of phenyl-glycol (B. 26, 1119, 
 1748), and in the distillation of jS-phenyl-hydroxy-a-naphtho-quinone 
 with zinc dust (A. 296, 28). The constitution of the two isomeric 
 phenyl-naphthalenes can be deduced from their oxidation products : 
 a-phenyl-naphthalene yields o-benzoyl-benzoic acid, whereas j3-phenyl- 
 naphthalene yields phenyl-a-naphtho-quinone : 
 
 X CH=CH yCOOH xCH=CH /CO CH 
 
 C H4 \C(C 6 H 5 ) =iH -" C ' H4 \CO.C 6 H 5 ; ^^\CH=t.C.H H *\CO-i.G ? H, 
 
 o-Phenyl-naphtha- o-Benzoyl- /3-Phenyl- Phenyl-a-naphtho 
 
 lene benzoic acid naphthalene quinone. 
 
 Olejftn - naphthalins. a- Vinyl - naphthalin C 10 H 7 .CH : CH 2 , b.p. 15 
 137, from a-naphthyl-magnesium bromide and acetaldehyde. a-Alyl- 
 naphthalin C 10 H 7 .CH 2 .CH : CH 2 , b.p. 266, from allyl bromide and 
 a-naphthyl-magnesium bromide. On heating with alcoholic KOH it 
 is transposed into the isomeric a-propenyl-naphthalin C 10 H 7 .CH.CH : 
 CH 3 , b.p. 10 138, which is also formed from a-naphthaldehyde, pro- 
 pionic anhydride, and Na propionate (C. 1897, II. 800 ; 1908, II. 1779). 
 a- and /Mso-propenyl-naphthalin C 10 H 7 .C(: CH 2 )CH 3 , a- b.p. 8 125, 
 j8- m.p. 45-47, b.p. 7 139, are formed from a- and j8-naphthyl-methyl- 
 ketone with CH 3 MgI ; the j8-compound direct, and the a-compound 
 by way of a-naphthyl-dimethyl-carbinol with acetic anhydride (C. 1901, 
 I. 1321). 
 
 Substituted Naphthalenes. 
 
 i. Halogen Derivatives, These are formed (i) by the direct sub- 
 stitution of the hydrogen atoms by halogens ; (2) by the replacement 
 of NH 2 groups in amido-naphthalenes by halogens, following Griess' 
 reaction (p. 60) ; (3) by the replacement of OH as well as of SO 3 H and 
 NO 2 groups in oxy-, nitro-, or sulpho-derivatives of naphthalene on 
 heating them with PC1 5 . The latter reaction is useful for determining 
 positions in naphthalene- and naphthol-sulphuric acids. 
 
 The union of the halogen atoms, and also that of the other sub- 
 stituents, like NO 2 , SO 3 H (cp. B. 26, 3028), in naphthalene derivatives 
 are, as a rule, less stable than in the corresponding benzene derivatives. 
 
 Fluoro-naphthalenes C 10 H 7 F : the a-form boils at 216, the )3- melts 
 at 59 and boils at 213. 
 
 Chloro-naphthalenes C 10 H 7 C1 : the a- boils at 263, while the j8- 
 melts at 56 and boils at 265. a-Chloro-naphthalene is produced (i) 
 in chlorinating boiling naphthalene ; further, (2) by action of alcoholic 
 potash upon naphthalene dichloride ; (3) from naphthalene-a-sulphonic 
 acid and PC1 5 ; (4) from a-amido-naphthalene. j3-Chloro-naphthalene 
 
NAPHTHALENE GROUP 659 
 
 is prepared from /3-amido-naphthalene or from j8-naphthol. Dichloro- 
 naphthalenes C 10 H 6 C1 2 : The ten possible isomerides are known : 
 i, 2- melts at 35 and boils at 281 ; I, 3- melts at 61 and boils at 289 ; 
 i, 4- melts at 68 and boils at 287 ; i, 5- melts at 107 ; i, 6- melts 
 at 48 ; i, 7- melts at 62 and boils at 286 ; i, 8- melts at 83 ; 2, 3- 
 melts at 120 ; 2, 6- melts at 135 and boils at 285 ; 2, 7- melts at 114 
 (B. 24, 3475, R. 653, 704, 709 ; 26, R. 536). 
 
 Triehloro-naphthalenes. There are fourteen isomerides ; see B. 
 29, R. 227. 
 
 Pentachloro-naphthalene C 10 H 3 C1 5 melts at 168. Perehloro- 
 naphthalene C 10 C1 8 melts at 203 and boils at 403. 
 \YBromo-naphthalenes C 10 H 7 Br : the a-variety melts at 5 and boils 
 at 279, while the j3-variety melts at 59 and boils at 282. lodo-naph- 
 thalenes C 10 H 7 I : the a-body is an oil, boiling at 305 ; the /2-body 
 melts at 54-5. a-Iodo-naphthalene is obtained by the introduction of 
 iodine into a carbon bisulphide solution of mercury dinaphthyl 
 Hg(C 10 H 7 ) 2 . See B. 29, 1408, for the bromo-iodo-naphthalenes, and 
 
 B. 27, 599, for the naphthyl-iodo-chlorides and iodoso-naphthalenes. 
 Consult B. 29, 1573, for jS-iodo-naphthalene. lodo-naphthalene and 
 naphthyl-phenyl-iodonium hydroxide, see B. 29, 1573 ; 33, 692 ; 
 
 C. 1901, II. 750. 
 
 2. Nitro-naphthalenes. a-Nitro-naphthalene C 10 H 7 -a-NO 2 consists 
 of yellow needles, melting at 61 and boiling at 304. It is pro- 
 duced on treating naphthalene with nitric acid at the ordinary tempera- 
 ture. When heated with PC1 5 it yields a-chloro-naphthalene. Chromic 
 acid oxidises it to v-nitro-phthalic acid. jS-Nitro-naphthalene, melting 
 at 79, is derived from jS-mtro-naphthylamine by replacing the NH 2 
 group by hydrogen, or, better, from jS-diazo-naphthalene nitrite C 10 H 7 N 
 =N.O.NO, by means of Cu 2 O (B. 20, 1494 ; 36, 4157). Transformation 
 into 4, i- and 2, i-nitroso-naphthol, see A. 355, 299. Different dinitro- 
 naphthalenes are obtained by the nitration of naphthalene at high 
 temperatures. Consult B. 29, 1243, 1521, for the separation of the i, 5- 
 and i, 8-compounds. The i,5~(a-) compound melts at 216 ; the i, 8- 
 (j8-) body melts at 170, and when heated with potassium cyanide yields 
 potassium naptho-cyaminate C 28 H 17 N 8 O 9 K. The two dinitro-naph- 
 thalenes, when heated with sulphuric acid and reducing agents, form 
 naphthazarin or dioxy-naphtho-quinone (B. 27, R. 959). 1, 3-(y-) 
 Dinitro-naphthalene, melting at 144, is obtained from amido-di- 
 nitro-naphthalene. At very low temperatures (50 to 55) nitric 
 acid and naphthalene form various dinitro-naphthalenes (B. 26, R. 362). 
 When naphthalene or dinitro-naphthalenes are boiled for some time 
 with fuming nitric and sulphuric acids (B. 28, 367) tri- and tetranitro- 
 naphthalenes are produced. These explode partly with violence on 
 heating. 
 
 3. Nitroso - naphthalenes. Mononitroso - naphthalene C 10 H 7 .NO, 
 melting at 89 and decomposing at 134, results from the action of 
 nitrosyl bromide upon mercury dinaphthyl, or by oxidation of naphthyl- 
 hydroxylamine with Ag 2 O or PbO 2 (B. 41, 1937). 
 
 1, 4-Dinitroso-naphthalene is a powder exploding at 120, and is 
 produced when a-naphtho-quinone-dioxime is oxidised with red prus- 
 siate of potash. 1, 2-Dinitroso-naphthalene, melting at 127 (B. 19, 
 349 ; 21, 434), is similarly formed from jS-naphtho-quinone-dioxime. 
 
660 ORGANIC CHEMISTRY 
 
 4. Amido-naphthalenes, Naphthylamines. (a) Primary Amines. 
 The naphthylamines, in contrast to the anilines, are very easily 
 obtained by heating the oxy-naphthalenes or naphthols with ammonia- 
 zinc chloride. 
 
 They are also formed by fusing naphthalene-sulphonic acids with 
 sodium amide. Naphthalene itself in the presence of phenol at 220 
 yields a-naphthylamine and I, 5-naphthylene-diamine (B. 39, 3011). 
 
 The acid sulphurous acid esters of naphtholene and naphthol deriva- 
 tives are transformed by treatment with ammonia in aqueous solution 
 into naphthylamines at temperatures as low as 100. This action is 
 reversed by boiling with alkaline bisulphite (/. pr. Ch. 2, 69, 49) : 
 
 NH, 
 
 C 10 H 7 .OSO 2 Me ^_ ~* C 10 H 7 .NH 2 . 
 
 SO jti Me 
 
 a-Naphthylamine C 10 H 7 -a-NH 2 , melting at 50 and boiling at 300, 
 results from the reduction of a-nitro-naphthalene, or on heating 
 a-naphthol with ZnCl 2 or CaCl 2 -ammonia to 250, and is synthetically 
 produced when aniline and zinc chloride are heated with pyro-mucic 
 acid. It crystallises in flat needles, which are especially beautiful when 
 they separate from aniline. It acquires a red colour on exposure to 
 the air, sublimes readily, and possesses a pungent odour. In general, it 
 behaves exactly like the phenylamines. 
 
 Sodium in amyl alcohol reduces it to a-tetrahydro-naphthylamine. 
 It is oxidised to a-naphtho-quinone when boiled with chromic acid. 
 Oxidising agents (chromic acid, ferric chloride, silver nitrate) produce 
 an azure-blue precipitate in the solutions of its salts : oxy-naphthyl- 
 amine C 10 H 9 NO (A. 129, 255). 
 
 In a-naphthylamine derivatives the amido-group can be replaced 
 by the hydroxyl group by treating with H 2 SO 3 and alkali (C. 1900, 
 
 II. 359). 
 
 j8-Naphthylamine, melting at 112 and boiling at 294, results from 
 jS-naphthol and ZnCl 2 -ammonia. It is odourless, and is not coloured by 
 ferric chloride and the like. Potassium permanganate oxidises it to 
 phthalic acid. /3-Tetrahy dro-naphthylamine is formed by its reduction . 
 
 Secondary and Tertiary Naphthylamines. Naphthyl-alkylamines are 
 formed, analogous to the alkyl-anilines, from the naphthylamines with 
 alkylogens, or upon heating the naphthylamine hydrochlorides with 
 alcohols. Also from the sulphurous esters of naphthols by heating 
 with aliphatic amines. The /?-naphthol, but not the a-naphthol esters, 
 react in this way with aromatic amines (/. pr. Ch. 2, 70, 345 ; 71, 433). 
 
 a-Naphthyl-methylamine C 10 H 7 NH.CH 3 , boils at 293 ; a-naphthyl- 
 ethylamine boils at 303 ; j8-naphthyl-dimethylamine C 10 H 7 -jS-N(CH a ) l 
 melts at 46 and boils at 305 (B. 13, 2053). The phenyl-naphthylamines 
 C 10 H 7 .NH.C 6 H 5 are formed when the hydrochlorides of a- and /3- 
 naphthylamines are heated with aniline and zinc chloride. On heating 
 the naphthylamines with zinc chloride or with HC1 to i8o-i90, or 
 with a- and jS-naphthol, various dinaphthylamines result. /3, f$- 
 Dinaphthylamine C 10 H 7 -j3-NH-jS-C 10 H 7 , melting at 171 and boiling 
 at 471, occurs as a by-product in the technical manufacture of /3- 
 naphthylamine. Heated to 150 with concentrated hydrochloric acid, 
 it breaks down into j8-naphthylamine and /3-naphthol. Heated with 
 sulphur it forms thio-dinaphthylamine NH(C 10 H 6 ) 2 S, corresponding to 
 
NAPHTHALENE GROUP 661 
 
 thio-diphenylamine. When sulphuric acid (80 per cent.) acts upon 
 j3-naphthylamine in the presence of oxidising agents, two naphthalene 
 nuclei unite and naphthidine (C 10 H 6 .NH 2 ) 2 results (B. 25, R. 949). 
 
 The acid derivatives of the naphthylamines show great similarity to 
 those of the anilines. The naphthyl-benzene sulphamides C 10 H 7 .NH. 
 SO 2 .C 6 H 5 manifest a rather remarkable deportment, similar to that of 
 the naphthols, in that they dissolve in the alkalies, and unite similarly 
 with diazo-salts, etc. (B. 27, 2370). Consult B. 25, R. 9, upon naphthyl- 
 carbamine-chlorethyl esters C 10 H 7 .NH.COOC 2 .H 4 C1 and their trans- 
 position products. See B. 29, R. 184, for the a-naphthylamine de- 
 rivatives of succinic, tartaric, and citric acids. 
 
 Substituted Naphthylamines. Haloid naphthylamines result by 
 direct substitution, or by the action of ammonia upon substituted 
 naphthols. 1, 2- and 1, 4-nitro-naphthylamines are formed by the 
 nitration of aceto-a-naphthylamine and its subsequent saponification. 
 The i, ^-body melts at 191. It is oxidised to a-naphtho-quinone. It 
 forms a-nitro-naphthalene by the elimination of the NH 2 group. 
 Boiling potassium hydroxide converts a-nitro-naphthalene into I, 4- 
 nitro-naphthol (B. 19,796; 25, R. 432). The i, 2-compound melts at 
 144, and yields j3-nitro-naphthalene and 2, i-nitro-naphthol. 
 
 l-Nitro-2-naphthylamine, melting at 127, is formed by the nitration 
 of aceto-j8-naphthylamine and subsequent saponification of the acetc- 
 derivative. Nitrous acid and alcohol convert it into a-nitro-naphtha- 
 lene. 2, 5- and 2, 8-Nitro-naphthylamines (B. 25, 2076) are produced 
 when /?-naphthylamine nitrate is introduced into concentrated sulphuric 
 acid. 
 
 Naphthylene Diamines. Diamido-naphthalenes, naphthylene-dia- 
 mines, are obtained by the reduction of dinitro- and nitro-amido- 
 naphthalenes, also by the decomposition of amido-azo-naphthalenes, 
 and when dioxy-naphthalenes and amido-oxy-naphthalenes are heated 
 with ammonia (B. 21, R. 839 ; 22, R. 42 ; 26, 188). 
 
 The o-naphthylene-diamines adapt themselves like the o-phenylene- 
 diamines to condensation reactions, in that they form naphtho-deriva- 
 tives of heterocy die rings. To a certain degree the o-naphthylene-dia- 
 mines in this respect resemble the i, 8- or ^>m"-compounds (p. 651). 
 
 1, 2-Naphthylene-diamine, melting at 98, is obtained by reduc- 
 tion from jS-nitro-a-naphthylamine and j8-naphtho-quinone-dioxime. 
 2, 3-Naphthylene-diamine, melting at 191, is derived from 2, 3-dioxy- 
 naphthalene by the action of ammonia at 240. These two bodies 
 yield naphtho-azimides with nitrous acid, anhydro-bases with car- 
 boxylic acids, quinoxalins with o-diketones, etc. (B. 25, 2714 ; 26, 
 188 ; 27, 761). Perfectly similar hetero-ring-formations are exhibited 
 by 1, 8- (peri-) naphthylene-diamine, melting at 67 and obtained from 
 i, 8-dinitro- or i, 8-dioxy-naphthalene ; however, it does not, in 
 contrast to the o-diamines, condense with o-diketones, like phen- 
 anthra-quinones, forming azines (B. 22, 861). 
 
 1, 3-Naphthylene-diamine melts at 96 ; has been obtained by nuclear 
 synthesis by the action of concentrated H 2 SO 4 upon y-phenyl-/3-imino- 
 butyro-nitrile (B. 28, 1953). i, 3~(w)- Naphthylene-diamine derivatives 
 are derived from naphthylamine-sulphonic acids, which contain the 
 SO 3 H group in the meta-position with reference to NH 2 , by the action 
 of amines. 
 
662 ORGANIC CHEMISTRY 
 
 (1, 4)-Naphthylene-diamine, melting at 120, results from the re- 
 duction of a-nitro-naphthylamine, and the decomposition of a-amido- 
 azo-naphthalene, by tin and hydrochloric acid. Ferric chloride con- 
 verts it into a-naphtho-quinone, and bleaching-lime changes it to 
 naphtho-quinone dichlorimine. 
 
 1, 5-Naphthylene-diamine, m.p. 189, has also been obtained from 
 a-naphthylamine, and i, 6-naphthylene-diamine, m.p. 78, from )3- 
 naphthylamine by fusing with NaNH 2 (B. 39, 3021). 
 
 1, 7-Naphthylene-diamine, m.p. 117 ; see B. 25, 2082. 2, 6-Naph- 
 thylene-diamine, m.p. 216 ; see A. 323, 130. 2, 7-Naphthylene-diamine, 
 m.p. 159 (J.pr. Ch. 2, 69, 89). 
 
 5. Diazo- and Azo-compounds of Naphthalene. By the action of 
 HNO 2 and NaNO 2 upon the salts of naphthylamines, diazo-compounds 
 are obtained which, like the benzene-diazo-compounds, form azo-dyes 
 with anilines and phenols. The diazo-amido-compounds probably 
 formed cannot be isolated. But a- and /3-naphthalene-diazonium 
 chloride and aniline give a- and jS-naphthalin-diazo-amido-benzol, 
 naphthyl-phenyl-triazene C 10 H 7 N : N.NHC 6 H 5 , m.p. 84 and 150 
 with decomposition. The a-body has also been obtained by other 
 methods (B. 40, 2400). 
 
 j8-Diazo-naphthalin-imide, m.p. 33; seeC. 1908, 1. 527 (/. pr. Ch. 
 2, 76, 461). l-Nitro-2-diazo-naphthalin-imide Ci H 6 [i]NO 2 [2]N 3 , m.p. 
 117, decomposes on heating with alcohol or glacial acetic acid into N 2 
 and i, 2-dinitroso-naphthalene (C. 1908, I. 526). 
 
 j8-Diazo-naphthalene acid, fi-naphthyl-nitramine C 10 H 7 -/3-NH.NO 2 , 
 yields on transposition 2-amido-i-nitro-naphthalene (B. 30, 1262). 
 
 Azo-naphthalenes. The reduction of nitro-naphthalenes to azoxy- 
 and azo-naphthalenes is less straightforward than in the case of the 
 nitro-benzols. a-Nitro-naphthalene gives on reduction with zinc dust in 
 neutral solution naphthyl-hydroxylamine and aa-azoxy-naphthalene 
 C 10 H 7 [a]N 2 O[a]C 10 H 7 , m.p. 127. The latter on further reduction 
 yields aa-azo-naphthalene, m.p. 190, red needles (A. 321, 61). 
 
 j8-Azo-naphthalene, m.p. 208, red flakes, is formed besides 
 
 C 10 H 6 N 
 dinaphtho-ortho-diazin I II and 2, 2-diamido-i, i-dinaphthyl by 
 
 C 10 H 6 N 
 reduction of jS-nitro-naphthalene (B. 36, 4153). 
 
 Benzol-azo-naphthalene C 10 H 7 .N 2 C 6 H 5 , m.p. 65. 
 
 o-Toluene-azo-naphthalene C 10 H 7 .N 2 .C 7 H 7 melts at 52 (B. 26, 143), 
 
 Naphthyl-azo-aeetie ester C 10 H 7 .N 2 .CH(COCH 3 )CO 2 R, melting at 94, 
 is formed from diazo-naphthalene chloride and sodium aceto-acetic 
 ester. Caustic potash changes it to naphthyl-acetone, and by the acid 
 decomposition it is resolved into naphthyl-azo-acetic acid (B. 24, R. 571). 
 
 A mido-azo-naphthalenes a- Amido-azo-naphthalene C 10 H 7 -a-N 2 -a- 
 C^Hg-c^-NHg, melting at 175, is formed by adding sodium nitrite 
 (i mol.) to the aqueous solution of naphthylamine hydrochloride 
 (2 mol.) ; the diazo-amido-naphthalene C 10 H 7 .N 2 .NH.C 10 H 7 first 
 formed undergoes a molecular rearrangement. Tin and hydrochloric 
 acid resolve a-amido-azo-naphthalene into a-naphthylamine and 
 (i, 4)-naphthylene-diamine. Naphthalene red belongs to the safranine 
 dyes and is produced when a-amido-azo-naphthalene is heated with 
 Na-naphthylamine hydrochloride. 
 
NAPHTHALENE GROUP 663 
 
 j8-Amido-azo-naphthalene, from j8-naphthylamine, melts at 156 
 (B. 19, 1282). 
 
 a-Naphthylamine-azo-benzene-sulphonic acid C 6 H 4 (Sp 3 H).N 2 .C 10 H 6 . 
 NH 2 ,from sulphanilic acid and naphthylamine hydrochloride, is coloured 
 orange by caustic potash and red by acids (test for nitrous acid). 
 
 The o-azo-compounds of jS-naphthyl-alphylamines, like benzene- 
 
 azo-/3-naphthyl-phenylamine C 10 H 6 <{ f 1 ^ ' ' 5 , when oxidised form 
 
 li|_2j.N I W .L/gJrlj 
 
 ammonium bases of the pseudo-azimide group, and when heated they 
 split off aniline, forming naphtho-phenazines (A. 28, 328) : 
 
 /N:N.C,H S o /N\ /N : N.C.H, 
 
 C " H '<NH.C.H 5 : r^l>* ; C " H <NH.C.H 8 ' 
 / \ 
 
 HO c.H 6 
 
 Compare further B. 18, 3132 ; 20, 1167 ; 24, R. 765, for the con- 
 stitution of the products resulting from the action of diazo-salts upon 
 jS-napthylamines, which are sometimes viewed as j3-quinone derivatives. 
 
 6. Hydrazin Derivatives of Naphthalene. Hyfaazo - naphthalene 
 C 10 H 7 .NH.NH.C 10 H 7 , melting at 275, corresponds to hydrazo-benzene. 
 It is formed on boiling azo-naphthalene with alcoholic sodium hydroxide 
 and zinc dust. When digested with hydrochloric acid it changes to the 
 isomeric naphthidin or diamido-dinaphthyl and i, i-diamido-2, 2-di- 
 naphthyl or dinaphthylin (B. 38, 136) ; J3j3-hydrazo-naphthalin, m.p. 
 141, is transposed into 2, 2-diamido-i, i-dinaphthyl by both acids and 
 alkalies (cp. benzidin transposition). 
 
 Naphthyl-hydrazins C 10 H 7 .NH.NH 2 are derived from the diazo- 
 chlorides of the two naphthylamines by the action of stannous chloride 
 and hydrochloric acid (B. 19, R. 303). The a-compound melts at 117, 
 the /^-modification at 125. They unite with the aldehydes and ketones 
 forming hydrazones ; these form naphthindol compounds by condensa- 
 tion, and manifest throughout the tendency to form derivatives and 
 hetero-ring formations similar to those shown by the phenyl-hydrazins 
 (B. 19, R. 831 ; 22, R. 672). On jS-naphthyl-hydrazones of sugars, see 
 B. 35, 1841. 2, 3-Naphthylene-dihydrazin C 10 H 6 [2, 3](NHNH 2 ) 2 , 
 m.p. 156, see B. 38, 266 ; /. pr. Ch. 2, 76, 205. 
 
 7. Sulphonic Acids. On digesting naphthalene with sulphuric acid 
 we have formed a- and /?-naphthalene-sulphonie acids. At lower 
 temperatures (80) the a-acid, melting at 90, predominates, while at 
 about 1 60 and with an excess of sulphuric acid the j3-acid, melting at 
 161, is the chief product. When heated with sulphuric acid the a-acid 
 passes into the j8-variety. They may be separated by means of the 
 calcium or lead salts. The free acids are crystalline, and deliquesce 
 readily. The a-acid decomposes upon heating with dilute hydro- 
 chloric acid to 200 into naphthalene and sulphuric acid, whereas the 
 j3-acid remains unaltered. 
 
 The a-sulpho-chloride melts at 66 and boils at 185 (13 mm.). The 
 fi-sulpho-chloride melts at 76 and boils at 201 (13 mm.) (/. pr. Ch. 
 2, 47, 49). Protracted heating of naphthalene with concentrated 
 sulphuric acid produces two isomeric disulpho-acids : 2, 6- and 2, 7-. 
 
 Naphthalene-disulphonie Acids. They are separated by crystallising 
 their chlorides from benzene (B. 9, 592). Additional disulphonic acids 
 of naphthalene have been prepared by sulphonating the naphthalene- 
 
664 ORGANIC CHEMISTRY 
 
 monosulphonic acids, by oxidising thio-naphthol-sulphonic acids, from 
 the naphthylamine-disulphonic acids, etc. A series of naphthalene- 
 trisulphonic acids has been made by similar indirect methods (B. 24, R. 
 6 54, 707, 715 ; 27, R. 81 ; 32, 3186 ; Proc. 126, 168) . Chloro-naphthalene- 
 sulphonic acids have been obtained in part by sulphonating the chloro- 
 naphthalenes, and in part by replacing the NH 2 group of the naphthyl- 
 amine-sulphonic acids by halogens (B. 24, R. 658, 707 ; 25, 2479 * 
 Ch. Z. 1895, 1114). Nitro-naphthalene-sulphonic acids are obtained by 
 sulphonating the nitro-naphthalenes or nitrating the chlorides of the 
 sulphonic acids (B. 26, R. 536). 
 
 Some naphthylamine-sulphonic acids possess technical value, inas- 
 much as they form desirable and valuable dyes by combining with the 
 tetrazo-compounds of the benzidine series : 
 
 (a) a-Naphthylamine, treated at 130 with an excess of concentrated 
 sulphuric acid, forms 1, 4-naphthylamine-sulphonic acid, naphthionic 
 acid, which can also be prepared from nitro-naphthalene with ammon- 
 ium sulphite by simultaneous reduction and sulphonation (Ch. Z. 1895, 
 1114; A. 78, 31). The acid crystallises with |H 2 O and dissolves 
 sparingly in water. Its sodium salt has the formula C 10 H 6 (NH 2 )SO 3 Na 
 +4H 2 O. When the acid combines with the tetrazo-derivative of 
 benzidine Congo red is produced. Tin and hydrochloric acid decom- 
 pose the latter with the formation of i, 2-naphthylene-diamine-<\- 
 sulphonic acid. See B. 29, 1978, for additional naphthylene-diamine- 
 sulphonic acids. 
 
 If a-naphthylamine be digested with sulphuric acid at 130 for 
 some time there results, instead of the i, 4-acid, 1, 5-napthylamine- 
 sulphonic acid, naphthal-idinic acid, and this finally gives place to 
 the i, 6-acid (B. 26, R. 534). 1, 8- or Peri-naphthylamine-sulphonic 
 acid is obtained from peri-nitro-sulphonic acid. The derivatives of the 
 i, 8-acid show a tendency to part with water with the production of 
 
 /SO, 
 sultams e.g. (SO 3 H 2 )C 10 H 4 </ | , 1, 8-naphth-sultam, 2, 4-disulphonic 
 
 /SO 2 
 acid (S0 3 H) 3 c 10 H 3 <^ | , 1, 8-naphth-sultam-trisulphonic acid (B. 27, 
 
 NH 2 
 
 2137). Peri-amido-naphthol derivatives are produced when these 
 sultams are fused with caustic potash (B. 28, R. 636). 
 
 Dimethyl-a-naphtnylamine-sulphonic acids (CH 3 ) 2 NC 10 H 6 SO 3 H, see 
 B. 35, 976. Naphthionates condense easily with aldehydes to RCH : 
 NC 10 H 6 SO 3 Me (C. 1901, II. 903). 
 
 (b) Four different, isomeric, fl-naphthylamine-sulphonic acids (A. 
 275, 262) are produced, according to the temperature, when ^S-naphthyl- 
 amine is sulphonated : 
 
 S0 3 H 
 -J Lso 3 H J L J L so 3 H- 
 
 TH, 
 
 NH 2 NH 2 
 
 a-acid /?-acid F- or <5-acid y-acid 
 
 (Baden acid) (Bronner's acid) (Dahl's acid). 
 
 These acids can also be prepared by the action of ammonia upon the 
 corresponding naphthol-sulphonic acids (p. 669). The j8- and the F- or 
 8-acids are particularly valuable, because by their combination with 
 
NAPHTHALENE GROUP 665 
 
 o-tetrazo-ditolyl beautiful red dyes having a blue tinge result. Certain 
 fi-naphthylamine-disulphonic acids are technically important : 
 
 H0 3 < 
 
 H0 3 S-1 i 
 
 HN 2 NH 2 
 
 Amido-sulphonic acid G Amido-sulphonic acid R d-Amido-sulphonic acid 
 (B. 24, R. 716) (B. 24, R. 707) (B. 24, R. 715)- 
 
 See B. 27, 1193, for additional jS-naphthyl-amido-poly-sulphonic 
 acids. These /?-naphthylamine-sulphonic acids, which contain a 
 sulpho-group in the m-position with reference to the NH 2 group, 
 readily exchange the sulpho-group for the amine residue when they are 
 heated with amines (B. 28, R. 311). 
 
 1, 4-Diazo-naphthalene-sulphonic acid c^H^^^O, diazo-naph- 
 
 thionic acid, is produced by the action of nitrous acid upon naphthionic 
 acid. It forms rocellin by combining with a-naphthol, and azorubin 
 S by its union with a-naphthol-a-sulphonic acid. 
 
 By the union of various azo-naphthalene-diazo-sulphonic acids e.g. 
 
 /N \ 
 CjoHjNsj.CjoHs^g^ />O with naphthol-monosulphonic acid, azo-black 
 
 dyes e.g. naphthol-black, wool-black, etc. result. 
 
 8. N aphthalene-sulphinic acids are derived by the reduction of the 
 chlorides of sulpho-acids ; on treating naphthalene-diazonium salts 
 with SO 2 and powdered Cu ; or by the action of SO 2 upon naphthalene 
 in the presence of A1C1 3 (B. 32, 1141 ; 41, 3319). a-Naphthalene- 
 sulphinic acid C 10 H 7 .SO 2 H melts at 84, while the -acid melts at 105 
 (B. 26, R. 271). These acids behave just like the benzene-sulphinic 
 acids (B. 25, 230). Mixed naphthyl-sulphones are prepared from their 
 salts by the action of alkyl bromides (B. 29, R. 979). 
 
 9. Naphthols. The oxy-derivatives of naphthalene or naphthols in 
 general show a deportment similar to that of the phenols. However, 
 their hydroxyl group is more reactive. They readily yield naphthyl- 
 amines with ammonia. They form esters and ethers more easily than 
 the phenols (B. 15, 1427 ; C. 1900, I. 131, 349). The naphthols occur 
 in coal-tar (A. 227, 143). 
 
 a-Naphthol C 10 H 7 -a-OH melts at 95, boils at 278-28o, and results 
 from a-naphthalene-sulphonic acid by fusing with potash, and from 
 a-naphthylamine by means of the diazo-compound, and upon fusing 
 a-naphthalene-sulphonic acid with alkalies. Its formation from 
 phenyl-iso-crotonic acid is very noteworthy. It is soluble with 
 difficulty in hot water, readily in alcohol and ether, crystallises in 
 shining needles, has the odour of phenol, and is readily volatilised. 
 Ferric chloride precipitates violet flakes of dinaphthol C 20 H 12 (OH 2 ) from 
 its aqueous solution. Nitrous acid converts it into 2, 1- and 4, i-nitroso- 
 naphthol ; chlorine in acetic acid changes it to various chlorinated 
 naphthols and keto-hydro-naphthalenes ; potassium chlorate and 
 hydrochloric acid oxidise it to dichloro-naphtho-quinone (A. 152, 301) ; 
 metallic sodium and alcohol reduce it to ar-tetrahydro-naphthol 
 (p. 412), while potassium permanganate in alkaline solution breaks it 
 down into carbo-phenyl-glyoxylic acid. The acetate C 10 H 7 -a-O.C 2 H 3 O 
 melts at 46. See B. 28, 3049, for the carbonate and phosphate. 
 
666 ORGANIC CHEMISTRY 
 
 j8-Naphthol C 10 H 7 --OH, melting at 122 and boiling at 286, is 
 derived from jS-naphthalene-sulphonic acid, or /3-naphthylamine. It is 
 readily soluble in hot water and crystallises in leaflets. Ferric chloride 
 imparts a greenish colour to the solution and separates a dinaphthol. 
 Nitrous acid and j9-naphthol yield I, 2-nitroso-naphthol. The acetate 
 C 10 H 7 -/3-OC 2 H 3 O melts at 70. On mixing glacial acetic solution of 
 /3-naphthol and mercury acetate we obtain jS-oxy-naphthyl-mercuric 
 acetate Ci H 6 (OH).Hg.OCOCH 3 (B. 31, 2624). 
 
 The bismuth salt of /3-naphthol has been recommended, under the 
 name of orpholum, as an intestinal antiseptic. 
 
 N ' aphthol-alkyl ethers are formed when the naphthols are heated 
 with alcohols and hydrochloric acid to 150 (B. 15, 1427), or from 
 naphthol-alkali salts with halogen alkyls or alkyl sulphates (B. 
 34, 3172) 
 
 a-Naphthol-ethyl ether boils at 277. jS-Naphthol-methyl ether and 
 ethyl ether have been called Jara-Jara and neroline and been used in 
 perfumery (B. 26, 2706). a- and jS-Dinaphthyl ethers melt at 110 and 
 106 (B. 13, 1840 ; 14, 195 ; C. 1906, I. 364). a- and /KNaphthyl- 
 phenyl ether, m.p. 55 and 93, from the diazo-naphthalenes with 
 phenol (C. 1902, II. 1470). a- and /3-Naphthoxy-acetie acid C 10 H 7 
 OCH 2 COOH, cp. B. 34, 3191. 
 
 Naphthol homologues, such as 2, 1- and 3, 1-methyl-naphthol C 10 H 6 
 (CH 3 )OH, melting at 80 and 92, have been prepared from phenyl-a- 
 and -jS-methyl-iso-crotonic acids (A. 255, 272). 1, 4-Dimethyl-3- 
 naphthol C 10 H 5 (CH 3 ) 2 OH, melting at 136, is obtained from santonin 
 (p. 724) (B. 28, R. 116, 619 ; 31, 1675). 1, 2-Methyl-naphthol C 10 H 6 [i] 
 CH 3 [2]OH, m.p. 110, from /Minaphthol-methane by reduction with 
 zinc dust and soda. HNO 2 has a peculiar action upon i, 2-methyl- 
 naphthol and its substitution products, producing either o-quinitrols or 
 o-methylene-quinones. 1, 2-Methyl-naphtho-quinitrol C 10 H 6 [2] : O[i] 
 (N0 2 )CH 3 , m.p. 60, heated above its m.p., gives 1, 2-methyl-naphtho- 
 quinol, m.p. 89, also obtained direct from i, 2-methyl-naphthol by 
 oxidation with CrO 3 in glacial acetic acid (C. 1907, II. 1415). 1, 2- 
 Naphtho-methylene-quinone C 10 H 6 [2] : O[i] : CH 2 , m.p. 132, yellow 
 needles, shows a reaction inertia resembling that of the o-methylene- 
 quinones of the benzene series (B. 39, 435 ; 41, 2614). 
 
 Substituted Naphthols. Substituted a-naphthols can be synthesised 
 from the substituted phenyl-iso-crotonic acids (cp. B. 26, R. 537). 
 Otherwise they are made by methods similar to those adopted with the 
 substituted phenols (p. 193). 
 
 Nitro-naphthols. 4, 1-Nitro-naphthol C 10 H 6 [4](NO 2 )[i]OH, melting 
 at 164, and 2, 1-nitro-naphthol C 10 H 6 [2]NO 2 [i]OH, melting at 195, 
 result from the oxidation of 4, i- and 2, i-nitroso-naphthol with 
 potassium ferricyanide or nitric acid (B. 25, 973), or by boiling the 
 corresponding nitro-naphthylamines with caustic potash. 
 
 2, 4-Dinitro-a-naphthol, melting at 138, is produced by the action 
 of nitric acid upon these nitro-naphthols or upon naphthalene-a- 
 sulphonic acid, a-naphthylamine, and a-naphthol-disulphonic acid (A. 
 152, 299). It is almost insoluble in water, sparingly soluble in alcohol 
 and in ether, decomposes alkaline carbonates, and forms yellow salts 
 with one equivalent of base. The salts dye silk a beautiful golden 
 yellow. The sodium salt C 10 H 5 (NO 2 ) 2 .ONa-f H 2 O finds use in dyeing, 
 
NAPHTHALENE GROUP 667 
 
 under the name of naphthalene yellow (Martius yellow), and is frequently 
 used to colour foods. The potassium salt of dinitro-naphthol-sulphonic 
 
 acid, CioH 4 (N0 2 ) 2 {W* K (B 24, R. 709), obtained by the nitration 
 
 of naphthol-trisulphonic acid, is naphthol yellow. 
 
 Trinitro-a-naphthol melts at 177. 
 
 a-Nitro-j8-naphthol, melting at 103, is produced in the oxidation 
 of a-nitroso-^S-naphthol, or from nitro-j8-naphthylamine by the action 
 of caustic potash. See B. 25, 2079, R. 670, and 31, 2418, for other 
 nitro-/3-naphthols and -naphthol ethers. 
 
 Amido-naphthols. These are derived by the reduction of nitro- 
 naphthols, by the action of ammonia upon dioxy-naphthalenes, the 
 decomposition of naphthol-azo-compounds, etc., etc., from dioxy- 
 naphthalenes with NH 3 , from naphthylamino-sulphonic acids by fusion 
 with potash, from naphthol-sulphonic acids, and direct from naphthalene 
 by fusion with Na amide (B. 39, 3006). 
 
 In the isonuclear, particularly the i, 3-amido-naphthols, the 
 NH 2 group is more readily displaced than in the heteronuclear 
 isomerides. 
 
 (1, 4)-Amido-a-naphthol C 10 H 6 (NH 2 ).OH results from the reduc- 
 tion of (i, 4)-nitro-naphthol, and by the decomposition of a-naphthol 
 orange C 10 H 6 (OH).N 2 .C 6 H 4 .SO 3 H. It is very unstable. It yields 
 a-naphtho-quinone by oxidation. 
 
 Its ethyl ether C 10 H 6 (OC 2 H 5 )NH 2 melts at 96. ^-Acetamido-i- 
 naphthol, naphthacetol, melting at 187, is especially well adapted for 
 the production of pure naphthol-azo-dyes. ^-Acetamino-i-naphthol- 
 ethyl ether, naphthacetin, melts at 189 (B - . 25, 3059). 
 
 2-Amido-a-naphthol, from 2, i-nitro-naphthol, oxidises in the 
 air to imido - oxy - naphthylamine or B - naphtho - quinonimide 
 O ,NH 
 
 6 ^ | T 
 
 , C 10 H 6 < , forming violet leaflets. 
 
 2, i-Amido-naphthol yields anhydro-bases or naphtho xazoles (see 
 B. 25, 3430) with carboxylic acids, etc. 
 
 {/N 
 2J \N, yellow 
 [i] : O 
 
 needles, m.p. 77, from i-chloro-2-naphthalene-diazonium sulphate 
 on standing in aqueous solution ; cp. quinone diazide (C. 1903, 
 
 1. 401). 
 
 l-Amido-/2-naphthol, from the reduction of i-nitro- or nitroso-j3- 
 naphthol, or by the decomposition of jS-naphthol orange, can be oxi- 
 dised to jS-naphtho-quinone. 1, 3-Amido-naphthol decomposes at 
 185 (B. 28, 1952). 1, 3-Amido-naphthol decomposes at 185 (B. 28, 
 1952). 2, 3-Amido-naphthol, melting at 234, is produced by the 
 action of concentrated ammonia at I35-I40 (B. 27, 763) upon 
 
 2, 3-dioxy-naphthalene. 
 
 1, 6-Amido-naphthol, m.p. 186, obtained from jS-naphthol, 2, 6- 
 and 2, 8-naphthol-sulphonic acids. 1, 5-Amido-naphthol, from a- 
 naphthol and i, 5-naphthol-sulphonic acid on fusion with Na amide. 
 1, 8-(peri-)-Amido-naphthol, m.p. 96, from i, 8-naphthylamine-sul- 
 phonic acid by fusion with potash (B. 39, 3331 ; 42, 4748). 1, 7-Amido- 
 naphthol, m.p. 165, see B. 42, 350. 
 
668 ORGANIC CHEMISTRY 
 
 Azo-naphthols. The naphthols can be readily combined with all 
 diazo-compounds to azo-derivatives. The a-naphthols add the diazo- 
 group as easily to the para-(4-) as to the ortho-(2-) position. However, 
 the p-position is preferred, and it is only when this is occupied that the 
 o-position is assumed (B. 29, 2945 ; 30, 50 ; 31, 2156). The final 
 products are o, p-dis-azo-compounds. With the j8-naphthols the 
 diazo-group attaches itself only to the a-position referred to the 
 OH group. 
 
 From a-naphthol we obtain in the first instance 1, 4-Naphthol-azo- 
 benzol (OH)[i]C 10 H 6 [4]N : NC 6 H 5 and l-naphthol-2, 4-dis-azo-benzol 
 (OH)[i]C 10 H 5 [2, 4](N :NC 6 H 5 ) 2 ; from j8-naphthol, 2-naphthol-l-azo- 
 benzol (OH)[2]C 10 H 6 [i]N : NC 6 H 5 . 
 
 These same compounds are also obtained by the action of phenyl- 
 hydrazin upon the naphtho-quinones. a-Naphtho-quinone-phenyl- 
 hydrazone is identical with i-naphthol-4-azo-benzene. jS-Naphtho- 
 quinone and phenyl-hydrazin form a compound which probably is 
 l-naphthol-2-azo-benzene, melting at 128, which cannot be directly 
 made from a-naphthol, because it is converted by diazo-benzene 
 chloride into i-naphthol-2, 4-dis-azo-benzene. 
 
 In spite of this formation, the azo-naphthols, like the azo-phenols, 
 must be regarded as true oxy-azo-compounds. In i-naphthol-2-azo- 
 benzol, the tendency towards the azo-structure is so strong that the 
 acyl-phenyl-hydrazones immediately transpose into the iso'meric 
 O-acyl-compounds, which are also obtained direct by acylation of 
 the l-naphthol-2-azo-benzol (A. 359, 353): 
 
 TT 
 
 H 
 
 l 
 
 /O 
 
 N.N(Ac)C 6 H 
 
 The naphthol-azo-dyes are of great importance in the colour in- 
 dustry. They are prepared almost exclusively in the form of their 
 sulpho-acids, which are formed (i) by the union of the naphthols with 
 diazo-sulphonic acids e.g. a-naphthol orange OH[i]C 10 H 6 [4].N 2 .C 6 H 4 . 
 S0 3 H, jS-naphthol orange OH[2]C 10 H 6 [i]N 2 C 6 H 4 SO 3 H, roeellin OH[2] 
 C 10 H 6 [i]N 2 .C 10 H 6 .SO 3 H, Bieberich scarlet OH[2]C 10 H 6 [i]N 2 .C 6 H 3 
 (SO 3 H)N 2 .C 6 H 4 SO 3 H, forms a- and j3-naphthols with diazo-benzene- 
 sulphonic acid, diazo-naphthalene-sulphonic acid, and sulpho-benzene- 
 azo-benzene-sulphonic acid ; (2) by the combination of diazo-salts 
 with naphthol-sulphonic acids. Cp. B. 29, 2945, for the dye- 
 stuffs obtained from naphthacetol and diazo-compounds. 
 
 Amido-naphthols, together with amines, are obtained by the reduc- 
 tion of azo-naphthols. The benzene-azo-p-naphthol ethers, when 
 reduced with SnCl 2 , yield 2-anilido-i, 4-amido-naphthol ethers Ci H 5 
 (OR)(NH 2 )(NHC 6 H 5 ) ; the aniline residue enters consequently into 
 the nucleus (B. 25, 1013) ; cp. semidin rearrangement (p. 146). 
 
 (d) Naphthol-sulphonic acids have been made in great numbers and 
 introduced into trade. In method of preparation and chemical 
 behaviour they exhibit nothing new, when compared with the phenol- 
 sulphonic acids. In the following paragraph, therefore, a table alone 
 of the representatives of these groups which possess a technical 
 value will be introduced : * 
 
 * Cp. Nietzki, Organische Farbstoffe. 
 
NAPHTHALENE GROUP 
 
 669 
 
 a-Naphthol-mono-sulphonic acids : 
 
 C 10 H 6 OH.SO 3 H 
 
 i 2 Schaeffer's a-acid, A. 
 
 152, 293- 
 
 i 3 B. 26, R. 31. 
 i 4 Neville and Winther's 
 
 acid, B.24,3157; 27, 
 3458 ; A. 273, 102. 
 
 i 5 L-acid, A. 247, 343. 
 
 i 7 B. 22, 993- 
 
 i 8 Schollkopf's acid, A. 
 247, 306 ; B. 23, 3088. 
 
 a-Naphthol-disulphonic acids : 
 
 C 10 H 5 OH.S0 3 H.S0 3 H 
 
 124 Disulphonic acid 
 for Martius' 
 yellow. 
 
 I 
 
 2 
 
 7 
 
 B."25, 1400. 
 
 I 
 
 3 
 
 8 
 
 e -Disulphonic 
 
 
 
 
 acid, B. 22, 
 
 
 
 
 3227. 
 
 I 
 
 4 
 
 6 
 
 DR.P. 41,957- 
 
 I 
 
 4 
 
 7 
 
 B. 24, R. 709; 
 
 
 
 
 29, 3 8. 
 
 I 
 
 4 
 
 3 
 
 Disulphonic acid, 
 
 
 
 
 S, B. 23, 3090. 
 
 a-Naphthol-trisulphonic acids : 
 C 10 H 4 OH.S0 3 H.S03H.S0 3 H 
 
 Sulphonic 
 acid for 
 naphthol 
 yellow 
 p. (401). 
 
 Sulphonic 
 acid for 
 Chromo- 
 trope, B. 
 24. R. 
 485. 
 
 fi-Naphthol-mono-sulphonic acids : 
 
 C 10 H 6 .OH.SO 3 H 
 
 2 6 Schaeffer's /?-acid, A. 
 
 152, 296. 
 2 8 Crocein acid, B. 22, 
 
 453 ; 24, R. 654. 
 2 5 y-Mono-sulphonic acid, 
 
 B. 22, R. 336. 
 2 7 F- or 5-acid, B. 20, 
 
 1426; 22, 724- 
 
 fi-Naphthol-disulphonic acids : 
 
 3 OH.S03H.S03H 
 
 236 R-acid, B. 22, 
 
 396. 
 
 237 8-Disulphonic 
 
 acid, B. 20, 
 
 2906. 
 248 Disulphonic acid, 
 
 C, B. 26, R. 
 
 259- 
 268 G-acid, B. 24, R. 
 
 707. 
 
 ft-Naphthol-trisulphonic acids : 
 
 C 10 H 4 OH.SO3H.SO 3 H.SO 3 H 
 
 2 3 6 8 B. 16, 462. 
 
 (Consult B. 27, 1207, 1209, for other 
 ,5-naphthol-trisulphonic acids.) 
 
 It is the acid of Neville and Winther of all these acids which 
 is principally used in the making of azo-dyes. It corresponds to 
 naphthionic acid. It is obtained in its present state by the action of 
 concentrated sulphuric acid upon a-naphthyl carbonate. The R-acid 
 and G-acid also meet with application. They unite with benzene and 
 naphthalene diazo-salts to form a series of Ponceau- and Bordeaux- 
 dyes of the most varying hues. The most important sulphonic acids 
 of jS-naphthol are produced together or one after the other in the 
 sulphonation of jS-naphthol in the manner represented in the following 
 diagram : 
 
 Schaeffer's jS-acid R-acid 
 
 2]-0-Naphthol { 
 
 2,3,6,8 
 
 Croceiin acid 
 
 G-acid. 
 
 The naphthol-sulphonic acids containing an OH and SO 3 H 
 group in the i, 8- or peri-position give rise to anhydrides having a 
 lactone nature ; these are the sultones (cp. sultames). 
 
670 ORGANIC CHEMISTRY 
 
 Naphtho-sultone C 10 H J | , melting at 154 and boiling above 360, 
 
 I [8]SO, 
 
 is formed by decomposing the diazo-derivative of peri-naphthylamine- 
 sulphonic acid. The sultone dissolves in hot alkalies, forming salts of 
 peri-naphthol-sulphonic acid. Sultones have also been obtained from 
 i, 3, 8- and i, 4, 8-naphthol-di- and i, 3, 6, 8-trisulphonic acids. 
 
 Amido-naphthol-sulphonic Acids are produced in the decomposition, 
 by reduction, of the azo-derivatives of naphthol-sulphonic acids, and 
 from nitroso-naphthols by reduction and sulphonation, both of which 
 processes can be worked in common if the nitroso-naphthols be treated 
 with sulphurous acid (B. 27, 23, 3050). In this way i, 2-nitroso- 
 naphthol yields 1, 2, 4-amido-naphthol-sulphonie acid C 10 H 5 [i]NH 2 [2] 
 OH[4]S0 3 H. The isomeric 2, i, 4-acid Ci H 5 [i]OH[2]NH 2 [4]SO 3 H 
 produces, even when oxidised in the air, imido-oxy-naphthalene-sul- 
 
 phonic acid SO 3 H.C 10 H 5 / | . This dye is black-violet in colour, and 
 
 is fast to light and alkalies (B. 25, 1400 ; 26, 1279). The 2, i, 6-acid 
 C 10 H 5 [i]OH[2]NH 2 [6]SO 3 H is used as a photographic developer under 
 the name of eikonogen. Important dyes, from the technical point of 
 view, are 2-amido-8-naphthol-6-sulphonic acids G (B. 25, R. 830 ; 29, 
 2267) and i-amido-8-naphthol-3, 6-disulphonic acid H (B. 26, R. 
 460, 917). Also 2-amido-5-naphthol-7-sulphonic acid (C. 1907, II. 
 1467), and some i, 8-amido-naphthol-sulphonic acids for black wool 
 dyes ; 2-amido-5-naphthol-i-sulphonic acid (C. 1911, I. 1263). 
 Farther amido-naphthol-sulphonic acids, see /. pr. Ch. 2, 80, 201. 
 
 Dioxy-naphthalenes. Nine of the ten possible isomerides are known. 
 The hydro-naphtho-quinones resulting from the reduction of the 
 naphtho-quinones are worthy of mention : 
 
 jS-Hydro-naphtho-quinone C 10 H 6 [i, 2](OH) 2 , melting at 60, 
 separates when a solution of j3-naphtho-quinone is boiled with sul- 
 phurous acid. It is strongly corrosive. It dissolves in the alkalies 
 with a yellow colour, which becomes an intense green upon exposure. 
 
 a-Hydro-naphtho-quinone C 10 H 6 [i, 4](OH) 2 , melting at 173, is 
 obtained from a-naphtho-quinone on boiling with hydriodic acid and 
 phosphorus, or with zinc and hydrochloric acid. Chromic acid readily 
 oxidises it to a-naphtho-quinone. 
 
 2, 6-Dioxy-naphthalene, m.p. 218, from Schaeffer's ^-naphthol- 
 sulphonic acid by fusion with potash, passes into the 2, 6- or amphi- 
 naphtho-quinone on oxidation with PbO 2 . From this it is recovered by 
 reduction with dilute HI (B. 40, 1410). 
 
 2, 3-Dioxy-naphthalene melts at 216 (B. 27, 762). Its mono- 
 methyl ether, m.p. 108, acts physiologically like guaiacol (B. 27, 762 ; 
 C. 1902, II. 554, 744). Also cp. A. 247, 356 ; B. 23, 519, etc. 
 
 1, 3-Dioxy-naphthalene, naphtho-resorcinol, melting at 124, is 
 obtained from i, 3, 4-amido-naphthol-sulphonic acid. It yields o-toluic 
 acid when fused with caustic potash (see B. 29, 1611). 
 
 2-Phenyl-i, ^-dioxy-naphthalene, melting at 166, is made by the 
 action of concentrated sulphuric acid upon a, y-diphenyl-aceto-acetic 
 ester (p. 653). It absorbs oxygen and changes readily to phenyl- 
 hydroxy-a-naphtho-quinone. I, 7 '-Dioxy '-naphthalene melts at 175 ; 
 see B. 29, 40 ; 2, j-dioxy-naphthalene, see B. 30, 1119. 
 
NAPHTHALENE GROUP 671 
 
 1, 8-(Peri-) dioxy-naphthalene, m.p. 140, from naphtho-sultone by 
 fusion with potash (A. 247, 356). The i, 8-dioxy-naphthalene-3, 6- 
 disulphonic acid (" chromo-tropic acid ") is obtained by fusing the 
 naphthol-trisulphonic acid \vith potash. It is a component of valuable 
 o-oxy-azo-dyes (B. 31, 2156). 
 
 Trioxy-naphthalenes. Two trioxy-naphthalenes, a- and j8-hydro- 
 juglones, occur in green walnut shells oijuglans regia (B. 18, 463, 2567). 
 a-Hydro-juglone C 10 H 5 [i, 4, 5](OH) 3 , melting at 169, is produced by 
 the reduction of juglone. In the air it rapidly oxidises to juglone. If 
 it be distilled it changes to j3-hydro- juglone, melting at 97, which 
 does not yield juglone upon oxidation. It reverts again to a-hydro- 
 juglone when boiled with dilute alcoholic hydrochloric acid. 
 
 1, 2, 4-Trioxy-naphthalene, m.p. 154, is obtained as a triacetate, 
 m.p. 134, by the action of acetic-anhydride-sulphuric acid upon 
 a- and -naphtho-quinone (A. 311, 345). 1, 3, 6-Trioxy-naphthalene, 
 m.p. 95, see B. 38, 3945. 
 
 1, 2, 5, 6-Tetraoxy-naphthalene, m.p. 154, by reduction of naphtha- 
 zarin (see below) (B. 28, R. 543). Reduction of iso-naphthazarin gives 
 1, 2, 3, 4-tetraoxy-naphthalene, and on further reduction a 1, 2, 3- 
 trioxy-naphthalene, naphtho-pyrogallol (A. 307, 16). 
 
 Thio-naphthols have been prepared by the reduction of the chlor- 
 ides of naphthalene - sulphonic acids or from diazo- naphthalenes. 
 Thio - naphthol, naphthyl - mercaptan C 10 H 7 .SH ; the a -form is liquid 
 and boils at 286. The jS-variety melts at 81 and boils at 286 
 (B. 22, 821 ; 23, R. 327). Phenyl-jS-naphthyl sulphide, melting at 51 
 (B. 24, 2266), is formed when the lead salt (C 10 H 7 -j8-S) 2 Pb is heated, 
 together with bromo-benzene. Different dinaphthyl sulphides have 
 been prepared by heating the naphthyl - lead mercaptides. Other 
 methods have been employed in making them (B. 26, 2816). Sulphur 
 chloride and ^-naphthol yield dioxy-dinaphthyl sulphide S(C 10 H 6 .OH) 2 , 
 melting at 211. This can be readily oxidised to a ^/ry^ro-compound 
 
 C 10 H 6 
 
 I (B. 27, 2993 ; 28, 114) (cp. quinones with two nuclei). 
 
 C 10 H 6 O 
 
 Naphthalene disulphydrates C 10 H 6 (SH) a ; see B. 25, 2735. 
 
 10. Quinones. On the basis of the diketone formula for the 
 quinones, six different naphtho-quinones are theoretically conceivable, 
 comprising three single-nucleus quinones, corresponding to the benzo- 
 quinones, and three double-nucleus quinones : 
 
 \\ f 1IS if 4 if 
 
 b 6 
 
 a-Naphtho- /3-Naphtho- 2, 3-Naphtho- i, 5-Naphtho- Amphi-naphtbo- i, 7-Naphtho- 
 quinone quinone quinone quinone quinone quinone. 
 
 Out of these, only the i, 4~(a)-, the i, 2-(/?)- and the 2, 6-(amphi-) 
 naphtho-quinone, and a derivative of the 2, 3-naphtho-quinone, have 
 hitherto been prepared. 
 
 a-Naphtho-quinone O=[i]C 10 H6[4]=:O, melting at 125, crystallises 
 from alcohol in yellow plates, subliming under 100. It possesses the 
 usual quinone odour, and is very volatile in a current of steam. It is 
 
672 ORGANIC CHEMISTRY 
 
 formed (i) by oxidising naphthalene in glacial acetic acid solution with 
 chromic acid ; (2) in the oxidation of I, 4-diamido- or I, 4-dioxy- 
 naphthalene, I, 4-amido-naphthol (A. 286, 70), a-naphthylamine, etc., 
 with sodium bichromate and sulphuric acid (B. 20, 2283) ; and (3) when 
 benzene-azo-naphthol is treated in the cold with PbO 2 and sulphuric 
 acid it is decomposed into diazo-benzene sulphate and a-naphtho- 
 quinone (B. 24, R. 733). 
 
 Nitric acid oxidises, a-naphtho-quinone to phthalic acid, while 
 a-hydro-naphtho-quinone is produced in its reduction. See the 
 nitrogen-quinone derivatives for its phenyl-hydrazin and hydroxyl- 
 amine derivatives. 
 
 Substituted a-Naphtho-quinones. a-Naphtho-quinone takes up two 
 atoms of chlorine or bromine ; the addition products readily part with 
 hydrochloric and hydrobromic acids and become j8-chloro- and j8-bromo- 
 a-naphtho-quinones, melting at 117 and 130. 2, 3-Diehloro- and 
 2, 3-dibromo-naphtho-quinone, m.p. 189 and 218. 
 
 In these halogen quinones, as in the ajS-dihalogen indones, the 
 halogen atoms are easily replaced by other groups. Thus, from the 
 dihalogen-a-naphtho-quinones we obtain with sodium-aceto-acetic 
 ester and sodium-malonic ester, with intermediate beautiful red and 
 blue colorations, such compounds as 
 
 C G H 4 \ /* ] -\ /* TT \ ' m -P- I02 . bromo-a-naphtho-quinone-malonic ester. 
 
 \CO C.CH(CO 2 C 2 H 5 ) 2 
 
 ' m - p - ^ 
 
 H 5 ' m ' P ' ' 7 ' cMoro-a-naphtho-qulnone-aceto- 
 acetic ester. 
 
 From these compounds many derivatives of the naphtho-quinone 
 series can be obtained by further transformations (B. 33, 566, 2402 ; 
 34, 1543). Condensation of 2, 3-dichloro-a-naphtho-quinone with 
 resorcin or orcin and sodium ethylate produces derivatives of phenylene- 
 naphthylene oxide C 6 H 4 <^' ^C^OH, which are closely related 
 to some decomposition products of brasilin, the so-called brasanes 
 (B. 32, 924 ; 41, 2373). 
 
 Hypochlorous acid converts a-naphtho-quinone into diketo-tetra- 
 
 COCH, 
 hydro-naphthylene oxide C 6 H/ | >o, which, by the breaking down 
 
 OvJ - 0x1 
 
 of the ethylene-oxide union, readily takes up the elements of water, 
 hydrogen chloride, and NH 2 C 6 H 5 . The primary addition products 
 sustain the most varied transpositions with great readiness, and form : 
 oxy-naphtho-quinone, chloroxy-naphtho-quinone, anilido-oxy-naphtho- 
 quinone, oxy-naphtho-quinone-anile, and other bodies ; cp. B. 25, 3599. 
 Amido-derivatives. Alkyl- or alphyl-amido-naphtho-quinones are 
 produced on heating primary amines together with a-naphtho-quinone : 
 2-anffldo-a-naphtho-quinone C 10 H 5 O 2 [2]NH.C 6 H 5 consists of red 
 needles, melting at 191. 2-Amido-a-naphtho-quinone, melting at 203, 
 is formed together with the isomeric oxy-a-naphtho-quinone-imide on 
 boiling amido-a-naphtho-quinone-imide with water (B. 27, 3337 ; 
 B. 28, 348). 
 
NAPHTHALENE GROUP 673 
 
 Oxy-naphtho-quinones. 2-Oxy-a-naphtho-quinone, naphthalic acid 
 C 10 H 5 O 2 [2]OH, melting at 188, is produced when anilido-naphtho- 
 quinone (see above) is boiled with dilute sodium hydroxide or oxy- 
 naphtho-quinone-anile with alcohol and sulphuric acid. j8-Phenyl- 
 /^-oxy-a-naphtlio-quinone, melting at 147, is prepared from jS-phenyl- 
 i, 3-dioxy-naphthalene by oxidising it in alkaline solution with air 
 (A. 296, 18) . lodo-oxy-naphtho-quinone, iodo-naphthalic acid C 10 H 4 O 2 [2] 
 OH [3] I, results from the iodation of naphthalic acid (B. 28, 348). Dyes 
 of the paroxazine and paradiazine series are easily made from the 
 o-oxy- and o-amido-naphtho-quinone derivatives (cp. also the cor- 
 responding naphtho-quinone-aniles and o-diamines) (B. 28, 353). 
 
 5-Oxy-a-naphtho-quinone, juglone, consists of yellow needles, melt- 
 ing with decomposition about I5o-i55. The best method to obtain 
 it consists in oxidising a-hydro- juglone with ferric chloride. It may 
 be synthetically prepared by oxidising (i, 5)-dioxy-naphthalene with 
 chromic acid (B. 20, 934). It dissolves in alkalies with a violet colour. 
 Nitric acid converts it into dinitro-oxy-phthalic acid (juglonic acid) 
 (B. 19, 164). 
 
 Oxy-juglone, dioxy-a-naphtho-quinone, melting with decomposition 
 at 220, is produced by the oxidation of the alkaline solution of juglone 
 on exposure to the air. An isomeric 5, 6-dioxy-a-naphtho-quinone, 
 naphthalizarin or naphthazarin, is formed on heating various a-dinitro- 
 naphthalenes with concentrated sulphuric acid in the presence of 
 reducing agents (B. 27, 3462, R. 959 ; A. 286, 26). It corresponds to 
 alizarine, which may be imagined to have arisen from naphthazarin 
 by the addition of a benzene nucleus. It is a valuable mordant dye. 
 
 Oxidation with MnO 2 and sulphuric acid yields the naphthazarin 
 called naphtho-purpurin, 5, 7, 8-trioxy-a-naphtho-quinone (C. 1899, 
 
 ii. 1053). 
 
 1 so-naphthazarin is probably a 2, 3-dioxy-a-naphtho-quinone. It 
 is produced from j8-naphtho-quinone by the action of a little bleaching- 
 lime as well as when 2, 3-oxy-anilido-a-naphtho-quinone (see above) is 
 heated with bromine (B. 25, 409, 3606). 
 
 Iso-naphthazarin, on reduction, gives tetra- and trioxy-naphthalene, 
 and, on oxidation, tetra-keto-naphthalene C 6 H 4 (CO) 4 , which partly 
 regenerates iso-naphthazarin, and phenyl-glyoxal-o-carboxylic acid, 
 with hydroxylamine or dioxime, m.p. 228, which, on oxidation, yields 
 dinitroso-a-naphtho-quinone C 6 H 4 [C 4 O 2 (NO) 2 ](A. 307, i). Closely 
 related to iso-naphthazarin is carminazarin, from oxidation of carminic 
 acid. On 6, 7-Dioxy-a-naphtho-quinone, see C. 1902, IL 744. 
 
 /2-Naphtho-quinone C 10 H 6 [i, 2]O 2 is produced on oxidising /?-amido- 
 a-naphthol with ferric chloride (B. 17, R. 531 ; 21, 3472). It consists 
 of red needles, which decompose at Ii5-I20. It is distinguished 
 from the para-quinones by being odourless and non-volatile. It closely 
 resembles anthraquinone, and especially phenanthraquinone ; like the 
 
 /CH CH 
 
 latter, it must be considered an ortho-diketone C 6 HX ~T ' 
 
 \OO . OU- 
 
 Like a-naphtho-quinone, it can add two atoms of chlorine and 
 bromine, and by the elimination of halogen hydrides ehloro- and bromo- 
 j8-naphtho-quinones are formed. 
 
 3, 4-Dichloro- and dibromo-/S-naphtho-quinone, m.p. 91 and 173 ; 
 jS-naphtho-quinone-malonie ester C 6 H 4 [C 4 O 2 H.CH(COOR) 2 ], m.p. 108. 
 
 VOL. II. 2 X 
 
674 ORGANIC CHEMISTRY 
 
 3-Chloro-j8-naphtho-quinone-aceto-acetie ester, m.p. 175, see B. 32, 
 264, 2412. 
 
 A little bleaching-lime converts j8-naphtho-quinone into iso- 
 naphthazarin (together with various other products, A. 286, 59). This 
 is a dioxy-a-naphtho-quinone. Such a rearrangement of 4~oxy- or 
 4-amido-j8-naphtho-quinone derivatives into oxy-a-naphtho-quinone 
 compounds is a phenomenon that has been frequently observed (cp. 
 oxy-a-naphtho-quinone-anile). An excess of bleaching-lime will 
 produce a rupture in the ring of /2-naphtho-quinone and convert it 
 into the lactone of o-phenyl-glycerol-carboxylic acid. 
 
 Similarly, 3-nitro-l, 2-naphtho-quinone, melting at 158, and 
 obtained by the nitration of j3-naphtho-quinone, is changed, on treating 
 it with chlorine and water, into o-di-derivatives of benzene. 
 
 3, 4-Diehloro-l, 2-naphtho-quinone, on the contrary, is first 
 rearranged by alkalies into dichlor - indene - oxy - carboxylic acid. 
 Potassium permanganate oxidises jS - naphtho - quinone to phthalic 
 acid, while sulphurous acid reduces it to j8-naphtho-hydroquinone, 
 and hydriodic acid to jS-naphthol (B. 26, R. 586). 
 
 6-Bromo-4-ehloro-l-methyl-2, 3-naphtho-quinone C 10 H 3 [6]Br[4]Cl 
 [i]CH 3 [2, 3]O 2 , yellow prisms, decomposing at 220, has been obtained 
 from the lead salt of the corresponding 2, 3-dioxy-naphthalene by the 
 action of iodine. It is odourless and non-volatile. Zinc dust and 
 glacial acetic acid partly reduce it to the corresponding dioxy-naphthal- 
 ene. With o-phenylene-diamine it combines like the ortho-diketones 
 to form a derivative of naphtho-phenazene (B. 42, 3375). 
 
 2, 6 - (amphi-) Naphtho - quinone C 10 H 6 [2, 6]O 2 , reddish - yellow 
 crystals, decomposed at I3O-I35, is formed by the oxidation of 
 2, 6-dioxy-naphthalene with PbO 2 in benzene solution. It is odourless 
 and non- volatile, and distinguished by its strong oxidising action. 
 Dilute HI reduces it to 2, 6-dioxy-naphthalene, with which it unites 
 molecularly to a blue green quin-hy 'drone, decomposing at 124. More 
 stable than amphi-naphtho-quinone itself is its dichloro-substitution 
 product, 1, 5-dichloro-amphi-naphtho-quinone, m.p. 206, obtained 
 similarly from i, 5-dichloro-2, 6-dioxy-naphthalene (B. 40, 1406, 3971). 
 
 Nitrogen Derivatives of the Naphtho-quinones. 
 
 i . Naphtho - quinone - phenyl - hydrazones. Unlike the benzene 
 quinone, both the a- and /?-naphtho-quinones unite with phenyl- 
 hydrazin and form phenyl-hydrazones (B. 28, 2414). The quinone- 
 phenyl-hydrazones are identical with the benzol-azo-naphthols (B. 32, 
 3100). The results of the action of unsym. acyl-phenyl-hydrazins 
 upon /3-naphtho-quinone must probably be regarded as O-acylated azo- 
 naphthols (B. 40, 2153 ; A. 359, 353). On the other hand, a-naphtho- 
 quinone with unsym. benzoyl- and methyl-phenyl-hydrazin have 
 yielded products C 10 H 6 < N ( COC H > C H and ^^^(CH.)^ 
 differing from those obtained by methylating and benzoylating i, 4- 
 
 naphthol-azo-benzol C 10 H 6 . and C 10 H 6 * (C. 1900, 
 
 I. 3i). 
 
 2. A' itroso-naphthols or Naphtho-quinoximes. These are produced 
 when the alcoholic solutions of the a- and jS-naphtho-quinones are 
 
NAPHTHALENE GROUP 675 
 
 boiled with hydroxylamine hydrochloride, and by the action of nitrous 
 acid upon the naphthols ; hence they can be regarded as nitroso- 
 naphthols C 10 H 6 (O)(NOH) or C 10 H 6 (OH)(NO) (cp. nitroso-phenols, 
 p. 198). Three isomeric bodies are formed ; their relation is expressed 
 by the following diagram : 
 
 N,O,_ 
 
 OH NOH 
 
 roH 
 
 a-Naphtho- a-Naphthoquinone- 
 quinone oxime 
 
 a-Nitroso- a-naphthol 
 
 O O 
 
 It - 
 
 NOH 
 
 It 
 
 a-Naphthol 0-Naphthol a-Nitroso- 
 
 /?-naphthol 
 0-Naphtho- 
 N ' quinpne- 
 
 /?-Naphtho- /?-Naphthoquinone- 
 quinone )5-oxime 
 
 /S-Nitroso-a-naphthol 
 
 The three isomerides are weak acids. Oxidation converts them into 
 the corresponding nitro-naphthols. 
 
 a-Nitroso-a-naphthol, a-naphtho-quinone-oxime, melting at 190, 
 and jS-nitroso-a-naphthol, j3-naphtho-quinone-/?-oxime, melting at 152, 
 are colourless compounds. /3-Naphtho-quinone-oxime is best made 
 from i-oxy-2-naphthoic acid with nitrous acid, when the carboxyl 
 group is split off (B. 26, 1280). a-Nitroso- j8-naphthol, f$-naphtho- 
 quinone-a-oxime, consisting of yellow-brown prisms, melting at 106, 
 precipitates different metals from their salts, and may be used to 
 separate nickel from cobalt, iron from aluminium, and for the deter- 
 mination of copper (B. 18, 2728 ; 20, 283) . Naphthol green (B. 24, 3741) , 
 a wool dye, is the iron salt of a-nitroso-/3-naphtnol-sulphonic acid 
 C 10 H 5 (SO 3 H)O(NOH), obtained by the action of nitrous acid upon 
 Schaeffer's j8-naphthol-sulphonic acid. Consult B. 30, 187, for the 
 product obtained in the action of NO 2 vapours upon Schaeffer's /?-acid. 
 
 The ethers of the nitroso-naphthols, derived from the silver salts 
 with methyl iodide and partly from the quinones with alkyl-hydroxyl- 
 amines, are reduced to amido-naphthols by tin chloride (B. 18, 715, 
 2225), a proof of the " oxime formula " of the nitroso-naphthols. 
 
 a-Naphtho -quinone-dioxime c 10 H 6 -i, 4-\^Qu * s formed from a- 
 
 nitroso-a-naphthol with hydroxylamine hydrochloride. It melts at 
 207 (B. 21, 433). 
 
 )3-Naphtho- quinone-dioxime c 10 H 6 -i, 2-^^ is derived from 
 
 j3-nitroso-a-naphthol and from a-nitroso-/2-naphthol by the action of 
 hydroxylamine hydrochloride (B. 17, 2064, 2582). It melts at 149. 
 
 After the manner of the glyoximes it forms the anhydride C 10 H 6 /pj;y>o, 
 
 melting at 78, when digested with alkalies. This compound may also 
 be designated naphtho-furazane. The reduction of the dioximes gives 
 rise to naphthylene-diamine. 
 
 3. N aphtho-quinone Chlorimides. These are made from amido- 
 
676 ORGANIC CHEMISTRY 
 
 naphthols, and the dichlorimides from the naphthylene diamines with 
 a bleaching-lime solution (B. 27, 238). They resemble the benzo- 
 quinone chlorimides, but do not exhibit the same dyestuff condensa- 
 tions as the former (B. 27, 242). 
 
 a-Naphtho-quinone-chlorimide C 10 H 6 [i, 4](NC1)O melts at 109. 
 
 a-Naphtho-quinone-diehlorimide, C 10 H 6 [i, 4] (NCI) 2 melts at 137. 
 
 /3-Naphtho-quinone-a-ehlorimide, melting at 87, and jS-naphtho- 
 quinone-/3-ehlorimide, decomposing at 98, are derived from 2, i- and 
 
 1, 2-amido-naphthols ; they yield ft, a- and a, j8-nitroso-naphthols 
 with hydroxylamine. j8-Naphtho-quinone-dichlorimide melts at 105. 
 
 4. Naphtho-quinone-imines and Aniles. The indo-phenol and indo- 
 aniline dyes of the naphthalene series belong to this group e.g. 
 a-naphthol blue or indo-phenol C 10 H 6 [i]O[4]N.C 6 H 4 N(CH 3 ) 2 which 
 results when naphthol interacts with dimethyl-p-phenylene-diamine or 
 nitroso-dimethyl-aniline. The simple a-naphtho-quinone-imide is not 
 known. 2-Amido-l, 4-naphtho-quinone-imine, di-imido-naphthol C 10 H 5 
 [2]NH 2 [i]O[4]NH (A. 154, 303) is produced in the oxidation of i-oxy- 
 
 2, 4-diamido-naphthalene. Boiling water changes di-imido-naphthol 
 to 2-oxy-l, 4-naphtho-quinone-imine, melting at 195 (B. 23, 2454) ; 
 aniline to 2-amido-l, 4-naphtho-quinone-anile C 10 H 5 [2]NHC 6 H 5 [i]O[4] 
 NCgHg, melting at 187 (B. 13, 123 ; 21, 391, 676) ; and further to 
 2-anilido-l, 4-naphtho-quinone-anile (C. 1910, I. 926) ; with hydroxyl- 
 amine an oxy-naphtho-quinone-oxime, which consists of two modifica- 
 tions, red and yellow, which can be changed one into the other (B. 
 29, 1415). 
 
 a-Naphtho-quinone-anile C 10 H 6 [i]O[4]NC 6 H 5 , red columns, m.p. 
 100, and j8-naphtho-quinone-anile C 10 H 6 [i]O[2]NC 6 H 5 , m.p. 103, 
 dark-green needles, are formed by alkaline condensation of nitroso- 
 benzol with a- and j8-naphthol respectively (B. 39, 1035). 
 
 2-Oxy-l, 4-naphtho-quinone-anile, melting at 240 with decom- 
 position, is produced by the action of aniline in the cold upon jS-naphtho- 
 quinone-4-sulphonic acid, the oxidation product of i, 2-amido-naphthol- 
 4-sulphonic acid. This is an instance of the rearrangement of a ft- into 
 an a-naphtho-qumone derivative. The p-diamines react in a manner 
 similar to aniline, so that in this way hydroxyl-indaniline dyes (see 
 above) can be obtained (B. 27, 25, 3050). 
 
 a-Naphtho-quinone-phenyl-di-imide C 10 H 6 (NH)(NC 6 H 5 ), melting at 
 129, is formed upon oxidising p-amido-naphthyl-phenyl-amine with 
 mercuric oxide (A. 286, 186). 
 
 ^S-Naphtho-quinone-imides, also called imido-oxy- or imido-ketone 
 naphthalenes, e.g. C 10 H 6 -i, 2-O(NH), are produced when the alkaline 
 solutions of i, 2-amido-naphthols are oxidised with air. 
 
 ii. ALCOHOLS OF THE NAPHTHALENE SERIES AND THEIR 
 OXIDATION PRODUCTS. 
 
 A. Alcohols. Naphtho-benzyl alcohols, naphthyl-carbinols C 10 H 7 . 
 CH 2 .OH, the a- melting at 60 and boiling at 301, and the ft- melting 
 at 80, result when their amines are treated with nitrous acid (B. 21, 
 257). The naphtho-benzyl chlorides C 10 H 7 CH 2 C1, the a- boiling at 178 
 (25 mm.) and the ft- melting at 47, are formed when chlorine acts upon 
 the two methyl-naphthalenes at a boiling temperature (B. 24, 3928). 
 
NAPHTHALENE GROUP 677 
 
 Naphtho-benzyl-amines menaphthyl-amines C 10 H 7 .CH 2 .NH 2 , the a- 
 boiling at 292 and the jS- melting at 60, have been made by the 
 reduction of the corresponding naphthoic acid thiamides, as well as of 
 the naphtho-nitriles. 
 
 a- and jS-Naphthyl-nitro-methane C 10 H 7 .CH 2 NO 2 , m.p. 73 and 72, 
 show isomeric phenomena similar to those of phthalyl-nitro-methane. 
 They have been obtained from the naphthyl-aceto-nitriles by the action 
 of ethyl nitrate and sodium ethylate and splitting up of the resulting 
 nitro-aceto-nitriles by boiling with soda (B. 38, 508). 
 
 a-Naphthyl-dimethyl-carbinol C 10 H 7 [a]C(OH)(CH 3 ) 2 , m.p. 80, from 
 a-naphthyl-methyl-ketone with CH 3 MgI, and from a-naphthyl-mag- 
 nesium bromide and acetone. a-Naphthyl-phenyl-carbinol C 10 H 7 CH 
 (OH)C 6 H 5 , m.p. 86, and a-naphthyl-diphenyl-carbinol C 10 H 7 C(OH) 
 (C 6 H 5 ) 2 , m.p. 133, from a-naphthyl-magnesium bromide, with benzalde- 
 hyde and benzo-phenone respectively (B. 37, 625, 2755). Other 
 naphthyl-carbinols, see C. 1910, I. 1144. 
 
 B. Aldehydes, Ketones. When the naphthyl-methyl alcohols are 
 oxidised, the products are : 
 
 a-Naphthaldehyde C 10 H 7 .CHO, boiling at 291, and /3-naphthalde- 
 hyde, melting at 59 (B. 20, 1115 ; 22, 2148 ; 44, 447). a-Naphthyl- 
 acetaldehyde C 10 H 7 .CH 2 .CHO, b.p. 13 i63-i66, from a-vinyl-naphtha- 
 lene with HgO and I (C. 1908, II. 1780). 
 
 a- and /3-Naphthyl-methyl-acetaldehyde C 10 H 7 CH(CH 3 )CHO, b.p. 4 
 132 and m.p. 53, by condensation of a- and /?-naphthyl-methyl-ketone 
 with chloro-acetic ester and sodium ethylate, the resulting glycide esters 
 being saponified with loss of CO 2 (C. 1908, I. 644). The a-compound 
 has also been obtained by the action of HgO and I upon a-propenyl- 
 naphthalene (C. 1908, II. 1780). 
 
 a-Naphthyl-methyl-ketone, aceto-naphthone C 10 H 7 .CO.CH 3 is derived 
 from naphthalene and acetyl chloride by means of aluminium chloride. 
 It melts at 34 and boils at about 295. Its chloride splits off hydrogen 
 chloride and becomes a-naphthyl-acetylene C 10 H 7 .C : CH. Potassium 
 permanganate oxidises the ketone to a-naphthyl-glyoxylic acid C 10 H 7 
 CO.COOH, melting at 113, which is also formed by the saponification 
 of naphthol cyanide obtained from a-naphthoyl chloride. 
 
 a-Naphthoyl-o-benzoie acid C 10 H 7 COC 6 H 4 COOH, m.p. 173, from 
 phthalic anhydride, naphthalene, and A1C1 3 (B. 33, 448). The action 
 of Na amide and alkylene iodide produces trialkyl-aceto-naphthones, 
 corresponding to aceto-phenones (C. 1910, II. 83). Other acyl- 
 naphthyl-ketones, see C. 1908, II. 948. Phenyl-naphthyl-ketones 
 C 10 H 7 COC 6 H 5 . see C. 1908, II. 1357. 
 
 1, 4- and 2, 1-Naphthol-aldehyde C 10 H 6 (OH)CHO, m.p. 181 and 81, 
 are best obtained by Gattermann's method in the form of aldimines 
 (B. 32, 284 ; C. 1901, I. 1010). 1, 2-naphthol-aldehyde, m.p. 59, has 
 been obtained by the condensation of a-naphthol with isatin chloride 
 (M. 29, 382 ; 30, 277). From naphthol-sulphonic acids, naphthol- 
 aldehyde-sulphonic acids are obtained by Reimer's aldehyde synthesis 
 (C. 1898, II. 799). 
 
 l-Naphthol-3-methyl-ketone C 10 H 6 [i](OH)[ 3 ](CO.CH 3 ), melting at 
 174, is formed from j8-benzal-laevulinic acid by condensation (B. 24, 
 3201). See B. 28, 1946, for 1, 2-naphthol-methyl-ketone. 
 
 Peri-dioxy-naphthyl-ketones (HO) 2 [i, 8]C 10 H 5 COR, from peri-dioxy- 
 
678 ORGANIC CHEMISTRY 
 
 naphthalene with carboxylic acids, and zinc chloride, are lac-forming 
 mordant dyes (C. 1901, II. 1287). 
 
 C. Naphthalene-monocarboxylic Acids. a-Naphthoie acid C 10 H 7 -a- 
 CO 2 H, melting at 160, is derived from a-naphtho-nitrile by saponifica- 
 tion (B. 20, 242 ; 21, R. 834) ; by fusing a-naphthalene-sulphonic acid 
 with sodium formate ; by the action of sodium on a mixture of a- 
 bromo-naphthalene and chloro-carbonic ester ; and from naphthalene, 
 urea chloride, and aluminium chloride (B. 23, 1190). j8-Naphthoie acid, 
 melting at 182, is formed from /?-naphtho-nitrile (B. 24, R. 725), as 
 well as by the oxidation of /S-alkyl-naphthalenes (B. 17, 1527 ; 21, 
 R. 355)- Both acids are decomposed when heated with baryta into 
 CO 2 and naphthalene. 
 
 Homologous Naphthalene-carboxylic Acids. a-Naphthyl-acetic acid 
 C 10 H 7 -a-CH 2 .COOH, melting at 131, has been made by the reduction 
 of a-naphthyl-glyoxylic acid, while the fi-acid, melting at 139, has been 
 prepared by means of the cyanide from /3-naphtho-benzyl chloride 
 
 (B. 29,2373). 
 
 a- and -Naphthyl-aerylie acids C ]0 H 7 .CH : CHCOOH, m.p. 205 and 
 196 respectively, are found by Perkin's synthesis from the naphth- 
 aldehydes with Na acetate and acetic anhydride. With Na propionate, 
 propionyl-naphthalene is mostly obtained, with loss of C0 2 (C. 1897, 
 
 fCH :CH 
 II. 800). a- and /?-Naphtho-eumarin C 10 H 6 - I , m.p. 141 and 
 
 1^ Cy LxV-) 
 
 118, and their alkylated derivatives, have been obtained by the general 
 cumarin methods from malic acid, aceto-acetic ester, etc. with H 2 S0 4 , 
 and from the naphthaldehydes by Perkin's synthesis (B. 36, 1966 ; 37, 
 4484 ; M. 30, 280). 
 
 /?-Phenyl- and /3-naphthyl-a-naphthoic acids are the chrysenic and 
 picenic acids (see Chrysene and Picene). 
 
 Substituted Naphthoic Acids. The nitration of a-naphthoic acid 
 produces 1,5- and 1, 8-nitro-naphthoic acids, melting at 239 and 
 275 respectively. Boiling nitric acid converts them into I, 5-(a)- 
 and i, 8-(j3-) dinitro-naphthalene. 1, 4-Nitro-naphthoic acid, melting 
 at 220, results upon saponifying the nitrile, which is formed 
 on treating the diazo-derivative of i, 4-nitro-naphthyl-amine with 
 potassium cuprous cyanide. 
 
 Ferrous sulphate and ammonia reduce the i, 5-acid to a stable 
 amido-naphthoie acid (1, 5)-, melting at 212 (B. 19, 1981), whereas the 
 same reagents reduce the i, 8-acid to (i, 8)- or peri-amido-naphthoic 
 acid, which, when free, passes like the i, 8-amido-sulphonic acids quite 
 
 readily into its inner anhydride, naphtho-styril C 10 H 6 /^^?. melting 
 
 L LJ-'^' -H 
 
 at 179 (B. 19, 1131). 1, 4- Amido-naphthoie acid melts at 177 (B. 
 
 28, 1842). 
 
 See B. 24, R. 637, for the nitro-/2-naphthoie acids. 2, 3-Amido- 
 
 naphthoic acid, melting at 214, results upon treating the corresponding 
 oxy-naphthoic acid with ammonia (B. 28, 3089). Further nitro- and 
 amido-naphthoie acids, see C. 1899, I. 288. 1, 3- and 1, 4-Diamido-/3- 
 naphthoic acids, m.p. 85 and 185, decompose into CO 2 and i, 3- or 
 i, 4-naphthylene-diamine. Their esters have been obtained by nuclear 
 synthesis (C. 1907, II. 68, 539). 
 
 Oxy-naphthoic acids, naphthol-carboxylic acids, containing the OH- 
 
NAPHTHALENE GROUP 679 
 
 and COOH-groups in the ortho-position, are prepared like the ortho- 
 phenol-carboxylic acids i.e. by heating the sodium naphtholates with 
 CO 2 under pressure. 
 
 1, 2-(a-) Naphthol-earboxylie acid C 10 H 6 [i](OH)[2](COOH), melting 
 at 186, is formed from a-naphthol and from ^-naphthol-sodium with 
 carbon dioxide and pressure at I2o-i45 ; 2, l-(j8)-naphthol-carboxylie 
 acid, melting with decomposition at 156, is similarly produced ; while 
 if j8-naphthol-sodium be heated more strongly, 2oo-25o, in a current 
 of carbon dioxide, the product will be 2, 3-naphthol-carboxylic acid, 
 melting at 216. The 2, i-(j3)-naphthol-carboxylic acid is distinguished 
 by the easy mobility of its carboxyl group. Heated alone, or when 
 boiled with water, it changes to j3-naphthol ; nitrous acid converts it 
 into a-nitroso-j3-naphthol, and diazo-benzene salts into benzene-azo-j3- 
 naphthol, etc. The 2, 3-acid, on the other hand, is very stable, and 
 resembles salicylic acid. Because of its striking and remarkable yellow 
 
 X CH 2 CO 
 colour the formula of a keto-dihydro-naphthoic acid C,H 4 <r 
 
 \CH =C.COOH 
 
 has been proposed for this acid. The behaviour of the acid toward 
 phenyl-hydrazin supports this view : it is very probable that at first 
 a hydrazin is produced, which subsequently, owing to indol condensa- 
 tion, forms a pheno-naphtho-carbazol-carboxylic acid (B. 29, 265 ; cp. 
 also M. 31, 917). With thionyl chloride, a- and /?-naphthol-carboxylic 
 acids yield the corresponding chlorides (C. 1901, II. 1119). The 2, 3- 
 naphthol-carboxylic acid with PC1 5 gives colourless 2-chloro-3-naphthoic 
 acid chloride, m.p. 56, b.p. 160 248 (B. 34, 4158). 
 
 From i, 2-naphthoic acid chloride and acetyl-2, 3-naphthoic acid 
 chloride, transposition with sodium-malonic ester yields /2-oxy- 1, 2- and 
 2, 3-naphtho-cumarin-naphtho-tetronic acid C IO H,{^ _^, m.p. 
 258 and 240 (A. 367, 253 ; 368, 43). 
 
 Naphtho-xanthones C 10 H 6 <^ ^>C 10 H 6 (B. 25, 1642) are produced 
 
 when the three o-naphthol-carboxylic acids are heated with acetic 
 anhydride. 
 
 (1, 8)- or peri-naphthol-earboxylie acid is derived from (i, 8)-amido- 
 naphthoic acid by means of the diazo-compound. It breaks down into 
 
 water and its y-lactone C 10 H 6 1 fg3 co / melting at 169. 
 
 2, 3-Oxy-naphthoic acid and diazo-benzene chloride yields a mixed 
 azo-compound. Reduction converts this into 1, 2, 3-amido-oxy- 
 naphthoie acid, which, on boiling with sulphuric acid, becomes 1, 2, 3- 
 dioxy-naphthoic acid. This can also be obtained from /?-naphtho- 
 hydroquinone and carbon dioxide, and by oxidation it is changed to 
 jS-naphtho-quinone-carboxylie acid (B. 28, 3089). From sodium a- 
 naphtho-hydroquinone and CO 2 we obtain 1, 4-dioxy-2-naphthoic acid, 
 m.p. 186 with decomposition, and also a condensation product of the 
 anthracene series (/. pr. Ch. 2, 62, 47). 1, 3-Dioxy-2-naphthoic acid, 
 naphtho-resorcin-carboxylic acid, m.p. 145 with decomposition, has been 
 obtained by saponifying its ethyl ester, m.p. 83, formed synthetically 
 by the action of concentrated H 2 SO 4 upon phenyl-acetyl-malonic ester 
 (A. 298, 383). For other dioxy-naphthoic acids, see B. 29, 39. 
 
 D. N aphthalene-di- and poly-carboxylic Acids. Six of these acids 
 
680 ORGANIC CHEMISTRY 
 
 are known. It is remarkable that the i, 8- or peri-acid, so-called 
 naphthalic acid' C 10 H 6 [i, 8](COOH) 2 , is produced by the oxidation of 
 acenaphthene and also from its semi-nitrile, which is made by saponify- 
 ing the diazo-derivative of peri-amido-naphthoic acid. The follow- 
 ing diagram represents the relations of a series of peri-naphthalene 
 derivatives : 
 
 NO, NO, N0 2 COOH 
 
 Peri-dinitro Peri-nitro-naph- 
 
 naphthalene thoic acid 
 
 NH 2 COOH OH COOH COOH COOH CH, CH, 
 
 vN/ 
 
 Peri-amido- Peri-naphthol- Naphthalic Acenaphthene. 
 
 naphthoic carboxylic acid 
 
 acid acid 
 
 Just as in the case of other peri-derivatives, so here naphthalic 
 acid when heated to 180 breaks down without melting into water and 
 its anhydride Ci H 6 (CO) 2 0, melting at 266, which also forms easily on 
 treating the acid with alcoholic HC1, and in many other processes. Like 
 phthalic anhydride, it condenses with phenol to phenol-naphthale'in 
 
 H)2 ( B - 28 R - 621 ) ; w ith malonic* acid ester and 
 
 ZnCl 2 to peri-naphtho-indandione C 10 H 6 /W^CH 2 (C. ion, I. 1633). 
 
 L [8]CO 
 
 Naphthal-imide C 10 H 6 (CO) 2 NH, m.p. 300, when treated with sodium 
 hypochlorite gives naphtho-styrile (B. 43 440). Cp. B. 28, 360; 32, 
 3283 ; C. 1902, II. 898 ; A. 327, 77 for naphthal-imide, -anile, and 
 -phenyl-hydrazile. 1, 2-Naphthalene-dicarboxylic acid, obtained by the 
 saponification of its nitrile, melts at 175 and passes into its anhydride, 
 melting at 105 (B. 25, 2475). 1, 5-Naphthalene-dicarboxylic acid, B. 
 29, R. 516. 
 
 l-Phenyl-naphthalene-2, 3-diearboxylie acid c e H 4 <~" =;:;: 
 
 \C(CgH.g) : GCOOH 
 
 is formed as an anhydride, m.p. 255, in a reaction recalling the forma- 
 tion of benzene rings from acetylenes, on heating phenyl-propiolic acid 
 C 6 H 5 C : CCOOH with acetic anhydride and on illuminating a benzene 
 solution of dibenzal-succinic anhydride. By the action of concentrated 
 H 2 SO 4 the colourless anhydride passes into allo-chryso-keto-carboxylic 
 acid, m.p. 288, in claret-coloured needles, which, on fusing with alkali, 
 yields an isomeric 1-phenyl-naphthalene-diearboxylic acid, m.p. 288 
 (B. 40, 3372, 3839 ; C. 1908, II. 1357) : 
 
 > C 10 H 5 \-COOH > C 10 H 6 COOH 
 
 * C 6 H 4 /CO * C 6 H 4 COOH 
 
 Naphthalene-tetraearboxylic acid C 10 H 4 [i, 4, 5, 8](CO 2 H) 4 , with the 
 
NAPHTHALENE GROUP 681 
 
 carboxyl groups in the two peri-positions of naphthalene, results when 
 pyrenic acid is oxidised (B. 20, 365). 
 
 Naphtho-nitriles, Cyano-naphthalenes. Naphtho-nitriles may be 
 obtained by the distillation of the alkali salts of the naphthalene- 
 disulphonic acids, or the phosphoric esters of the naphthols with 
 potassium cyanide or yellow prussiate of potash (B. 21, E. 834), or from 
 the naphthylamines by means of the diazo-compounds. 
 
 a-Naphtho-nitrile, a-cyano-naphthalene C 10 H 7 .CN, melting at 37 
 and boiling at 298, has also been prepared from formo-naphthalide 
 C 10 H 7 .NH.COH. 
 
 j8-Cyano-naphthalene melts at 66 and boils at 304. 1, 2-Dieyano- 
 naphthalene C 10 H 6 [i, 2](CN) 2 , melting at 190, is produced when i, 2- 
 chloro-naphthalene-sulphonic acid is distilled with potassium ferro- 
 cyanide (B. 25, 2475). For additional isomeric dicyano-naphthalenes, 
 see A. 152, 289 ; J. 1869, 483, etc. 
 
 /C(CN) : COH 
 
 1, 4-Dicyano-2, 3-dioxy-naphthalene C 6 H 4 < | t m . p . 291, 
 
 is formed by nuclear synthesis in the condensation of oxalic ester with 
 o-xylylene cyanide. 
 
 12. Dinaphthyl-, Dinaphthyl-methane, and Trinaphthyl-me thane 
 Derivatives. Different isomeric dinaphthyls have been made by con- 
 ducting the vapours of naphthylene through bronze tubes heated 
 to redness, by heating naphthalene with A1 2 C1 6 , or from bromo-naph- 
 thalene and iodo-naphthalene with sodium, and by heating mercury 
 dinaphthyl Hg(C 10 H 7 ) 2 , etc. (B. 28, R. 184). 
 
 The aa-dinaphthyl, on heating with A1C1 3 to 140, joins the two 
 naphthalene residues in the peri-position and yields a hydrocarbon 
 consisting of five condensed benzene-rings, and called perylene 
 C 10 H 8 /^Hc 10 H 6 , bronze-coloured flakes, b.p. 262-265, the con- 
 
 HJ J 
 
 stitution of which is determined by its formation from i, 8-di-iodo- 
 naphthalene on heating with copper bronze (B. 43, 2202). The 4, 4- 
 diamido-i, i-dinaphthyl or naphthidins, corresponding to the benzidins 
 or 4, 4-diamido-diphenylenes, are formed besides the 1, l-diamido-2, 2- 
 dinaphthylene or dinaphthylinene, by transformation of hydrazo- 
 naphthalenes, or direct from the naphthylamines by the action of 80 
 per cent, sulphuric acid, in the presence of oxidising agents such as 
 ferric oxide (B. 25, R. 949). In the same way the naphthols give 
 dinaphthols with ferric chloride. On binuclear quinones of the di- 
 naphthyl series, see /. pr. Ch. 2, 62, 31 ; B. 42, 1058. 
 
 Dinaphthyl-methanes and their derivatives are formed by methods 
 used in forming the diphenyl-methane series : a 2 - and /? 2 -dinaphthyl- 
 methane CH 2 (C 10 H 7 ) 2 , m.p. 109 and 92 ; a, /3-dinaphthyl-methane, m.p. 
 96, see B. 44, 449 ; a 3 -trinaphthyl-methane (C 10 H 7 ) 3 CH, m.p. 101, from 
 its carbinol by reduction with HI in glacial acetic acid (B. 44, 1105). 
 Trichloro-ethylidene-aa-dinaphthyl CC1 3 CH(C 10 H 7 ) 2 , m.p. 156, on heat- 
 ing with alcohol and zinc dust, is converted into aa-naphtho-stilbene 
 C 10 H 7 CH : CHC 10 H 7 , m.p. 161. The latter is closely related to picene, 
 into which it is converted on superheating. j8/?-Naphtho-stilbene, m.p. 
 255 (B. 38, 509). From naphthylamine, and from naphtholene with 
 aldehydes, we obtain, with particular ease, alkylidene-dinaphthyl- 
 
682 ORGANIC CHEMISTRY 
 
 amines (C. 1900, II. 481) and alkylidene-dinaphthols. The products 
 formed from jS-naphthol with aldehydes part with water and become 
 xanthenes, hence they in all probability contain the alkylidene groups 
 in the o-position with reference to the hydroxyls : /?-dinaphthol- 
 methane, melting at 190, yields, with POC1 3 , dinaphtho-xanthene 
 C 10 H. 6 <(^ . \C 10 H e , while benzaldehyde and j8-naphthol at once form 
 
 \Cri 2 / 
 
 ms-phenyl-naphtho-xanthene C6H 5 CH(C 10 H 6 )O (B. 25, 3477 ; 26, 83), 
 together with an acetal. Sodium-/3-naphthol and chloroform at 150 
 produce an anhydride of trioxy-trinaphthyl-methane HOC 10 H 6 CH 
 [C 10 H 6 J 2 O, m.p. 273, which is also formed by the condensation of 
 J8-naphthol and jS-naphthol-aldehyde (C. 1901, I. 945, 1010). 
 
 act- and ^-Dinaphthyl-carbinol (C 10 H 7 ) 2 CHOH, from a- and 0- 
 naphthyl-magnesium bromide and formic ester ; aaa- and aajS-tri- 
 naphthyl-earbinol (C 10 H 7 ) 3 COH, m.p. 169 and 264. The dinaphthyl- 
 carbinols, but, strangely enough, not the trinaphthyl-carbinols, show 
 the same mobility of the hydroxyl group as the diphenyl- and triphenyl- 
 carbinol. HC1 easily produces the corresponding chlorides (C 10 H 7 ) 2 
 CHC1, from which aa- and jSj8-dinaphthyl-acetie acid (C 10 H 7 ) 2 CHCOOH, 
 m.p. 228 and 179 respectively, are obtained, with Mg and CO 2 . On 
 treatment with zinc and HC1, the dinaphthyl-carbinols easily split off 
 water and pass into aa- and Pfi-dinaphtho-fluorene (B.42, 2377; 43, 2824). 
 
 Numerous dyes of the naphthyl-diphenyl, dinaphthyl-phenyl, and 
 trinaphthyl series have been prepared by known methods, but are of 
 no practical interest, on account of their slight solubility and high 
 price (B. 37, 1899). 
 
 13. Acenaphthene. Acenaphthene, or peri - efhylene - naphthylene 
 
 ( [i]CH 2 
 C 10 H 6 -{ | , melting at 95 and boiling at 277, is a peculiar deriva- 
 
 l [8]CH 2 
 
 tive of naphthalene, which is obtained by conducting a-ethyl-naphtha- 
 lene through a red-hot tube, or by the action of alcoholic potash upon 
 a-bromo-ethyl-naphthalene C 10 H 7 .C 2 H 4 Br. It also occurs in coal-tar. 
 Inasmuch as acenaphthene is oxidised by sodium bichromate and 
 sulphuric acid to naphthalic acid, the side chain C 2 H 4 must be arranged 
 in the two peri-positions (i and 8) of naphthalene. Acenaphthene- 
 quinone C 10 H 6 (CO) 2 , melting at 261, is a by-product in this oxidation. 
 
 Zinc dust and acetic acid reduce it to acenaphthenone C 10 H 6 .CH 2 .CO, 
 melting at 121, while hydriodic acid and phosphorus change it to 
 
 bis-acenaphthylidene (C 10 H 6 .CO.C : ) 2 , melting at 294, and alkalies 
 decompose it into naphthaldehydic acid (B. 26, R. 710 ; A. 290, 195 ; 
 
 c. 1899, ii. 378 ; 1909, n. 775) : 
 
 C 10 H 6 < 
 
 i /CO Hn /CHO CH(OH) 
 
 Bis-acenaphthylidene ;.C 10 H 6 < | -^ ^C 10 H 6 < or C 10 H 8 < >O 
 
 X CO X COOH X CO 
 
 Acenaphthene- Naphthaldehydic acid, 
 
 quinone 
 
 Acenaphthenone 
 
 The monoxime of acenaphthene-quinone C 12 H 6 O(NOH), m.p. 230, 
 
NAPHTHALENE GROUP 683 
 
 is converted into naphthalimide by Beckmann's transposition (C. 1903, 
 I. 881). 
 
 By bromination, nitration, or acidulation, acenaphthene is substi- 
 tuted in the 4-position, as shown by the conversion of the corresponding 
 derivatives into derivatives of naphthalic acid (A. 327, 77 ; B. 43, 
 
 2473). 
 
 Acenaphthene-quinone easily unites in the presence of condensing 
 agents like A1C1 3 , ZnCl 2 , with aromatic hydrocarbons, amines, and 
 
 /CO 
 phenols to form diaryl-acenaphthenones c io H 6\ c / R ) (B. 43, 2915). 
 
 9, 9-Diphenyl-acenaphthenone C 10 H 6 <^ H , m.p. 174, results 
 
 /CfOH^C H 
 also from the 9, lo-diphenyl-acenaphthene-glycol c io H 6\/Q H J c 6 H 5 ' 
 
 m.p. 156, the product of the action of C 6 H 5 MgBr upon acenaphthene- 
 quinone on heating with concentrated HC1 (pinacolin transposition). 
 Withindoxyl andthio-indoxyl (j8-oxy-thio-naphthene) acenaphthene- 
 
 quinone condenses to a violet or red vat dye C H 4\NH/ : C \ C H anc ^ 
 
 C J < C s> C : C <CH, < B - 41 > 3331 : C. 1909, II. 775). 
 
 When the vapour of acenaphthene is conducted over lead oxide 
 heated to redness, two atoms of hydrogen split off and aeenaphthylene 
 CH 
 
 results. This forms yellow plates (B. 26, 2354), melts at 
 CH 
 
 92, and boils at 270 with decomposition. Chromic acid also oxidises 
 it to naphthalic acid. 
 
 On a synthesis of substituted acenaphthylenes, see A. 369, 157. 
 On heating acenaphthene with sulphur to about 290, we obtain 
 
 dinaphthylene-thiophene C 10 H 6 { _ s _ } C 10 H 8 , red needles, m.p. 278, 
 beside the yellow hydrocarbon [~C 10 H 6 <^1 : trinaphthylene-benzol, 
 
 m -P- 387 (B. 36, 962). By reduction with hydrogen and finely 
 divided nickel we obtain from acenaphthene tetrahydro-acenaphthene, 
 b.p. 254 (C. 1901, II. 202) and decahydro-acenaphthene, b.p. 230- 
 234 (B. 42, 2094). 
 
 14. HYDRO-NAPHTHALENE DERIVATIVES. 
 
 Hydro-naphthalene compounds attach themselves to naphthalene 
 just as the hydro-aromatic benzene derivatives do to benzene. 
 Naphthalene and its derivatives take up hydrogen and the halogens 
 more readily than the compounds of benzene. Those naphthalene 
 derivatives which have added hydrogen to one nucleus alone are 
 remarkable and interesting, because they manifest in one substance 
 the differences which prevail between an aromatic and a hydro-aromatic 
 or alicyclic nucleus. While the non-hydrogenised nucleus of the 
 respective naphthalene compounds retains the aromatic properties, the 
 hydrogenised alicyclic nucleus assumes, on the contrary, the nature of 
 a fatty radicle, and as a consequence the whole system acquires the 
 character of an homologous benzene derivative (Bamberger, A. 257, i). 
 
 A. Dihydro-naphthalene Derivatives. Dihydro-naphthalene C 10 H 10 , 
 melting at 15 and boiling at 212, is formed when naphthalene is 
 
684 ORGANIC CHEMISTRY 
 
 reduced with sodium in a boiling ethyl-alcohol solution. The entering 
 hydrogen atoms assume the i, 4-position, because the hydride yields 
 o-phenylene diacetic acid when it is oxidised. It can be viewed as 
 the hydrocarbon of a-naphtho-quinone. Dihydro-naphthalene re- 
 sembles the olefins e.g. ethylene in that it readily takes up two 
 univalent atoms or radicles. Thus with bromine it forms a dibromide, 
 with hypochlorous acid a glycol-chloro-hydrin. Tetrahydro-naphthylene 
 oxide can be easily obtained from the latter, and is capable of rearranging 
 itself to 1, 2-dihydro-j3-naphthol C 10 H 10 O, boiling at i62-i68 (28 mm.), 
 which may be oxidised to dihydro-iso-cumarin-carboxylic acid, and 
 when it splits off water naphthalene is produced (A. 288, 74) : 
 
 /CH=CH /CH, CH /CH, CH\ /CH, CHOH /CH = CH 
 
 C 6 H 4 < I ->C,H/ || ->QH/ | >0->C 8 H/ | ->C 6 H/ 
 
 X CH=CH \CH, CH X CH 2 CH/ \CH = CH X CH=CH 
 
 Naphthalene Dihydro-naphthalene Tetrahydro- Dihydro-0-naphthol Naphthalene. 
 
 naphthalene oxide 
 
 XH^eHjJ.CH 
 
 Phenyl-hydro-naphthalene C 6 H 4 <^ II , m.p. 50, results from 
 
 phenyl-bromo-tetrahydro-naphthoic acid on boiling with soda solution, 
 or, better, with diethyl-aniline (A. 306, 235). 
 
 Naphthalene dichloride C 10 H 8 C1 2 is a yellow oil formed when 
 naphthalene is treated with potassium chlorate and hydrochloric acid. 
 It changes to a-chloro-naphthalene at 4O-50, arid by the elimination 
 of hydrogen chloride. 
 
 Dihydro-naphthoic Acids. Sodiiim amalgam reduces the a- and 
 j8-naphthoic acids, two hydrogen atoms being added to the nucleus 
 already carrying the carboxyl group, and in the cold there result 
 unstable, and when heat is applied stable, dihydro-naphthoie acids 
 C 10 H 9 .CO 2 H. The former are unsaturated at /? and y, the latter at 
 a and j8 : 
 
 a-Stable melting at 125 ; /3-stable melting at 161. 
 a-Unstable ,, 91 ; 6-unstable ,, 104. 
 
 The unstable modifications pass into the stable modifications on 
 boiling them with caustic soda. Potassium permanganate oxidises 
 the stable a-acid to hydro-cinnamic acid, while the unstable acid 
 yields oxalic acid and phthalic acid. The dibromide of the unstable 
 .j8-acid, in contrast with the stable modification, readily changes to a 
 brominated lactone. All these facts point to the following formulae 
 for the stable a- and the unstable j8-acid (A. 266, 169) : 
 
 /CH, CH 2 /CH, CH, /CH=CH /CH CHBr 
 
 C,HA I ->C e HX C 6 H 4 < *C,HX 
 
 \C(COOH)=CH VOOH COOH \CH,.CH.COOH \CH, CH.CO O 
 
 Stable dihydro-a- Unstable dihydro-/?- 
 
 naphthoic acid naphthoic acid. 
 
 The dihydro-j8-acids, when oxidised with potassium ferricyanide, 
 revert again to jS-naphthoic acid. 
 
 The stable a-dihydro-naphthoic acid, like other a, jS-unsaturated 
 carboxylic acids, adds sodium-aceto-acetic ester with formation of a 
 8-ketonic acid ester, which, however, immediately discards alcohol, and 
 condenses to a phenanthrene (B. 31, 1896). 
 
 a-Phenyl-dihydro-jS-naphthoic acid C 10 H 8 (C 6 H 5 )COOH, m.p. 191, 
 
NAPHTHALENE GROUP 685 
 
 is obtained by condensation of dibenzyl-propionic acid by means of 
 glacial acetic sulphuric acid (A. 306, 156). 
 
 B. Tetrahydro - naphthalene Derivatives. Tetrahydro - naphthalene 
 C 10 H 12 , boiling at 206, is formed in the reduction of naphthalene with 
 sodium in amyl alcohol solution ; also from ar-tetrahydro-naphthyl- 
 amine by the elimination of the NH 2 group ; hence the H atoms are 
 only present in the one nucleus. Naphthalene tetrachloride C 10 H 8 C1 4 , 
 melting at 182, is produced when chlorine is conducted into a chloro- 
 form solution of naphthalene. Boiling alcoholic potash changes it to 
 dichloro-naphthalene. See B. 28, R. 392, for the oxidation of naphtha- 
 lene tetrachloride. Consult B. 24, R. 713, for the chlorine addition 
 products of chlorinated and sulphur-containing naphthalenes. Naphtha- 
 lene tetrabromide melts at m (C. 1897, I. 984). 
 
 The naphthylamine and naphthol hydrides are particularly interest- 
 ing. Sodium acting upon the boiling amyl alcohol solution of the 
 naphthols and naphthylamines causes these bodies to add four hydrogen 
 atoms each to one nucleus. If the latter carries the NH 2 or OH group, 
 the body formed no longer possesses the character of a naphthylamine 
 or a naphthol, but has that of a benzene homologue, amidated or 
 bearing the OH group in the side chain. Should, however, the non- 
 substituted nucleus be hydrogenised, then the products acquire the 
 nature of homologous anilines or phenols. E. Bamberger, who first 
 observed these relations and explained them, designated the second 
 class of tetrahydro-derivatives as aromatic (ar-), and the first class as 
 aliphatic-cyclic or alicyclic (ac-) : 
 H. 
 
 H(NH.) H, NH, N(NH,) 
 
 ac-Tetrahydro- ar-Tetrahydro- ar-, ac-Tetrahydro- 
 
 a-naphthylamine ^-naphthol i, 5-naphthylene-diamine. 
 
 a-Naphthylamine and a-naphthol upon reduction yield ar-tetra- 
 hydro-a-naphthylamine and naphthol, while the jS-compounds form 
 both the ar- and the ac-tetrahydro-derivative ; the latter predominates. 
 i, 5-Naphthylene-diamine yields ac-, ar-tetrahydro-naphthylene-dia- 
 mine, which, by elimination of the aromatic NH 2 group, forms ac-tetra- 
 hydro-a-naphthylamine. 
 
 ar-Tetrahydro-naphthylamines NH 2 .C 6 H 3 : (C 4 H 8 ). The a-body 
 boils at 275 and the j3-form at 276. They are feeble bases and form 
 diazo- and azo-compounds. They exercise a reducing power with salts 
 of the noble metals. By oxidation with potassium permanganate all 
 yield adipic acid and oxalic acid. 
 
 Chromic acid oxidises the a-compound to ar-tetrahydro-a-naphtho- 
 quinone C 6 H 2 O 2 : (C 4 H 8 ), melting at 55, which in every respect re- 
 sembles benzo-quinone and possesses much greater oxidising power 
 than a - naphtho - quinone. ac - Tetrahydro - naphthylamines C 6 H 4 : 
 (C 4 H 7 .NH 2 ) ; the a-body boils at 246 and the - at 249. They are 
 strong bases, which absorb carbon dioxide from the air. They do not 
 form diazo-derivatives. Potassium permanganate ruptures the hydro 
 genised ring and produces o-cinnamo-carboxylic acid. 
 
 From the /?-, ac-tetrahydro-naphthylamine, by means of d-bromo- 
 
686 ORGANIC CHEMISTRY 
 
 camphorosulphonic acid, an optically active dextro-rotatory modifica- 
 tion has been obtained (C. 1899, II. 255 ; 1900, I. 862). 
 
 ac-, ar-Tetrahydro-1, 5-naphthylene-diamine NH 2 .C 6 H 3 :(C 4 H 7 NH 2 ), 
 melting at 77 and boiling at 261, combines in itself both the properties 
 of an aromatic and of an alicyclic amine. It contains an asymmetric 
 carbon atom, and has been resolved into a dextro- and a laevo- 
 modification. 
 
 ar-Tetrahydro-a-naphthol OH.C 6 H 3 : (C 4 H 8 ), melting at 69 and 
 boiling at 265, is also derived from ar-tetrahydro-a-naphthylamine by 
 means of the diazo-derivative. 
 
 ae-Tetrahydro-/?-naphthol C 6 H 4 : (C 4 H 4 OH) is an oil, boiling at 
 264. It exhibits the character of a fatty alcohol and resembles 
 similarly constituted camphor alcohols, like menthol and borneol. 
 
 A series of tetrahydro-naphthalene derivatives has been obtained, 
 starting with dihydro-naphthalene : Thus, phenol and the latter form 
 tetrahydro-naphthyl-phenol C 6 H 4 : (C 4 H 7 .C 6 H 4 OH), boiling at 130 (B. 
 24, 179), while bromine changes it to dihydro-naphthalene dibromide 
 C 6 H 4 : (C 4 H 6 Br 2 ). Boiling potassium carbonate, or transformation 
 with silver acetate and subsequent saponification, converts the latter 
 
 into tetrahydro-naphthylene glycol c 6 H 4 '- me lting at 
 
 \LJdL 2 CrlUri 
 
 I 35 (cis-form) and 118 (trans-form), which by oxidation is broken 
 down into o-phenylene-diacetic acid. It is an analogue of ethylene- 
 glycol. The chloro-hydrin (above) C 10 H 10 C1(OH), melting at 117, with 
 caustic potash yields tetrahydro-naphthylene oxide C 10 H 10 0, melting at 
 43 and boiling at 258, which manifests all the chemical properties of 
 ethylene oxide (I. 298). Bases have converted the chloro-hydrin into 
 a series of " alkines," of which mention may be made of 
 
 Trimethyl - oxy - tetrahydro - naphthylene - ammonium hydroxide 
 
 yCH 2 .CHOH 
 
 \CH CHN(CH OH' Because of its intimate connection with 
 
 choline (I. 309). The feebler alkalies convert this oxide into the 
 
 f*T-T /"* TT 
 
 isomeric fi-keto-tetrahydro-naphthalene C 6 H 4 / i 2 , melting at 
 
 \CH 2 CO 
 
 18 and boiling at 138 (16 mm.), which can also be prepared by 
 the distillation of o-phenylene-propion-acetic acid (B. 28, 745). It 
 behaves like a fatty ketone (B. 27, 1547) w i* n sodium bisulphite, 
 phenyl-hydrazin, and hydroxylamine. a-Keto-tetrahydro-naphthalene 
 
 <QTT _ QTT 
 CQ ^ _ H 2 is obtained by intramolecular condensation of 
 
 y-phenyl-butyric acid chloride by means of A1C1 3 (C. 1899, I. 792). 
 
 The chlorine addition products of the naphtho-quinones are diketo- 
 tetmhydro-naphthalene derivatives. They result from the action of Cl 
 upon the corresponding dioxy-naphthalenes or naphtho-quinones (A. 
 300, 180 ; 334, 342) : 
 
 r M /CO - CO r TT /CO -CCl a r TT /CO - CCL r TT /CC1 2 CO 
 
 c ' H4 \cci 2 -cci 2 ' c ' H4 \co-cci 2 ' c H4 \cci 2 -co ' C6H <cci 2 -co' 
 
 Diketo-tetrahydro-naphthylene oxide c H *<^o-CH/ >O ' meltin S 
 at 136, is produced by the action of bleaching-lime upon a-naphtho- 
 quinone (p. 671 and A. 286, 71). 
 
NAPHTHALENE GROUP 687 
 
 The tetrahydro-naphthoic acids are also classified into aromatic and 
 alicyclic. ar-Tetrahydro-a-naphthoic acid COOH.C 6 H 3 : (C 4 H 8 ), with 
 an amide melting at 182, is derived from its nitrile, a rearrangement 
 product from ar-tetrahydro-a-naphthalene-diazo-chloride and potassio- 
 copper cyanide. 
 
 ac-Tetrahydro-naphthoie acids, the a- melting at 85 and the j8- at 
 96, are formed when naphthoic and dihydro-naphthoic acids are 
 reduced with sodium amalgam. They resist the action of potassium 
 permanganate more strongly than the dihydro-acids. In comparison 
 with the latter they thus prove themselves to be saturated acids. The 
 long-continued action of the oxidant finally changes them to phthalic 
 and oxalic acids (A. 266, 202). 
 
 For the splitting up of the tetrahydro-naphthoic acids into their 
 optically active components, see C. 1906, II. 962. 
 
 ac-Phenyl-tetrahydro-jS-naphthoic acid C 6 H 4 [C 4 H 6 (C 6 H 5 )COOH] , 
 m.p. 177, results from the reduction of phenyl-bromo-tetrahydro- 
 naphthoic acid, m.p. 205, obtained synthetically by the action of Br at 
 o upon the chloroform solution of benzyl-phenyl-iso-crotonic acid 
 (A. 306, 231). 
 
 ac-Tetrahydro-naphthalene-diearboxylie acid C 6 H 4 [C 4 H 6 (CO 2 H)2], 
 melts at 199, with the production of its anhydride, melting at 184. 
 The latter is also formed on heating potassium tetrahydro-naphthalene 
 tetracarboxylate, the ester of which has been synthesised from o-xyly- 
 lene bromide and the sodium derivative of the dimalonic acid ester 
 (B. 17, 448). Tetrahydro-1, 5-naphthalene-diearboxylic acid melts at 
 238 (B. 29, R. 517). 
 
 C. Hexa,- octo-, deca-, and dodecahydro-naphthalenes C 10 H 14 , 
 C 10 H 16 , C 10 H 18 , and C 10 H 20 , boil at 200, i85-i9O, i73-i8o, and 153- 
 158 respectively. They have been obtained by the action of hydriodic 
 acid and phosphorus upon naphthalene (B. 16, 796, 3032 ; A. 187, 164). 
 
 Decahydro-naphthalene has also been obtained by reduction with 
 H and Ni at 160. Deca-hydro-a- and -j8-naphthol C 10 H 17 OH, m.p. 62 
 and 75, b.p. 14 109 and 112, are easily formed by the reduction of 
 a- and /3-naphthol with H and Ni ; by rejection of water they yield 
 two isomeric oetohydro-naphthalenes, b.p. 190 and 191, by oxidation 
 with CrO 3 the corresponding ketones C 10 H 16 O, m.p. 32 and b.p. 240, 
 the oximes of which are reduced by Na and alcohol to a- and /?-deea- 
 hydro-naphthylamine C 10 H 17 NH 2 , b.p. 14 97 and 112 (C. 1911, I. 318). 
 
 III. PHENANTHRENE GROUP. 
 
 Phenanthrene occurs, together with anthracene, in coal-tar and 
 in the so-called " stubb," a substance obtained (together with 
 fluoranthene and pyrene) in the distillation of mercury ores in Idria. 
 It is prepared synthetically (i) (with diphenyl, anthracene, and other 
 hydrocarbons) from various benzene compounds, by conducting their 
 vapours through a red-hot tube e.g. from toluene, stilbene, diphenyl, 
 and ethylene, and particularly from dibenzyl and o-ditolyl : 
 
 UjHg.CHj CgH^.CH CgH 4 . 
 
 I * I || < | 
 
 C a H 5 .CH 2 C a H 4 .CH C 8 H 4 .CH 3 
 
 Dibenzyl Phenanthrene o-Ditolyl. 
 
688 ORGANIC CHEMISTRY 
 
 (2) Sodium acting on o-bromo-benzyl bromide also produces it, 
 together v/ith anthracene. 
 
 C 6 H 4 CH ^ ^Br[i]C 6 H 4 [2]CH 2 Br Br[i]C 6 H 4 [ 2 ]CH 2 Br ^ ^ cn /C,H 4 \ cil 
 
 C 6 H 4 CH Br[i]C 6 H 4 [2]CH 2 Br BrCH 2 [2]C 6 H 4 [i]Br \ c s H 4/ 
 
 Phenanthrene. Anthracene. 
 
 (3) It also appears in the condensation of cumarone with benzene 
 (B. 23, 85) : 
 
 L CH C 6 H 4 CH 
 
 J +C 6 H 6 > I || 
 
 II v>gl"j. \_/Jrl 
 
 Cumarone Phenanthrene. 
 
 Chrysene is similarly formed from cumarone and naphthalene, and 
 amido-naphthalene (p. 694) from furfurane and aniline. 
 
 (4) When the diazo-derivative of o-amido-a-phenyl-acetic acid is 
 acted upon with copper powder, phenanthrene-carboxylic acids (B. 29, 
 496) result : 
 
 CH C 6 H 4 .N 2 OH CH C 6 H 4 
 
 II * II I 
 
 COOH.C C 6 H 5 COOHC C 6 H 4 
 
 This reaction recalls the formation of diphenyl from benzene and 
 diazo-benzene, as well as that of diphenyl-ketone from the diazo- 
 derivative of o-amido-benzo-phenone. 
 
 (5) Quite analogous to the synthesis of a-naphthol from phenyl- 
 iso-crotonic acid is the formation of 4-oxy-phenanthrene by heating 
 
 -naphthyl-iso-erotonie acid c " u '^^^tH ~ ~^ Cl H Kc(OHTcH- 
 
 (6) The following synthesis of phenanthrene, starting from a naphtha- 
 lene derivative, is of interest : Dihydro-j3-naphthoic acid ester (i) 
 condenses with aceto-acetic ester to a diketo-octohydro-phenanthrene- 
 carboxylic ester, which, on saponification and rejection of CO 2 , yields 
 octohydro-diketo-phenanthrene (2), which in turn gives phenanthrene 
 by zinc-dust distillation. 
 
 (i) (2) (3) 
 
 CH 2 CH 2 CC0 2 R _^ CH 2 CH 2 CH CO CH 2 __^ CH=CH C CH=CH 
 
 ^6-^-'-4 CJbd CgH 4 CH CH 2 CO C 6 H 4 C CH=CH 
 
 Phenanthrene in accordance with these methods of production must 
 be viewed as a derivative of diphenyl, in which two ortho-positions of 
 the two benzene rings are joined by the group CH=CH, which there- 
 fore constitutes, with the four carbon atoms of the two benzene rings, 
 a third normal benzene ring : 
 
 6 _5 43 
 
 7 CH/ ^c c/ SCH 2. 
 
 ^CHC^ V 
 
 8 
 
 The oxidation 01 phenanthrene leads to a similar conclusion. 
 Phenanthraquinone is the first product, and by continued oxidation it 
 yields diphenic acid or diphenyl-o 2 -dicarboxylic acid : 
 
 C 6 H 4 .CH C 6 H 4 .CO C 6 H 4 .CO 2 H 
 
 C 6 H 4 .CH C 6 H 4 .CO C 6 H 4 .CO 2 H 
 
 Phenanthrene Phenanthraquinone Diphenic acid. 
 
PHENANTHRENE GROUP 689 
 
 Since phenanthrene and its derivatives have been obtained as dis- 
 integration products of the important alkaloids morphia, codein, and 
 thebain, the chemistry of the phenanthrenes has, of late, been carefully 
 studied. 
 
 Phenanthrene C 14 H 10 crystallises in colourless plates, melting at 
 99 and boiling at 340. It dissolves readily in ether and benzene, 
 but with more difficulty in alcohol and water. The solutions exhibit a 
 blue fluorescence. 
 
 The picrate C 14 H 10 .C 6 H 2 (NO 2 )3.OH separates in yellow needles, 
 melting at 144. Consult A. 196, 34 ; B. 19, 761, for a method of 
 isolating phenanthrene from crude anthracene. 
 
 Alkylated Phenanthrenes. 1- and 3-methyl-phenanthrene C 14 H 9 .CH 3 , 
 m.p. 123 and 65, result from the synthetic i- and 3-methyl-phen- 
 anthrene-9-carboxylic acids by rejection of CO 2 . 9, 10-Dimethyl- 
 phenanthrene C 14 H 8 (CH 3 ) 2 , m.p. 139, by reduction of 9, lo-dimethyl- 
 9, lo-dioxy-dihydro-phenanthrene with HI and phosphorus (B. 39, 
 3110 ; A. 362, 250). 9, 10-Diphenyl-phenanthrene C 14 H S (C 6 H 5 ) 2 , m.p. 
 235, has been obtained by nuclear synthesis by the action of A1C1 3 upon 
 tetraphenyl-ethylene (B. 38, 203). It is also produced by a remarkable 
 atomic displacement in the reduction of benzoyl-phenyl-fluorene with 
 HI and phosphorus, a reaction corresponding to the formation of 
 tetraphenyl-ethylene from jS-benzo-pinacolin (B. 37, 2887) : 
 
 C 6 H 4 \ /COC 6 H 5 rC 6 H 4 \ /CH(OH)C 6 H 5 n _ C 6 H 4 .C.C.H 6 
 
 C 6 H 4 / \C 6 H 5 " LC 6 H 4 / \C 6 H 5 * C 6 H 4 .C.C 6 H 5 
 
 Halogen Phenanthrenes. By the action of chlorine upon phen- 
 anthrene substitution products are formed : 9, 10-dichloro- and 2, 9, 
 10-triehloro-phenanthrene C 14 H 8 C1 2 and C 14 H 7 C1 3 , m.p. 161 and 124 
 (B. 39, 3891) ; octochloro-phenanthrene C 14 H 2 C1 8 , m.p. 27o-28o, is 
 split up on further chlorination into C 6 C1 6 and CC1 4 . Bromine in 
 CS 2 solution forms an addition product, phenanthrene dibromide 
 C 14 H 1(} Br 2 , which splits off HBr and passes into 9-bromo-phenanthrene 
 C 14 H 9 Br, m.p. 63. The latter is oxidised by chromic acid to phen- 
 anthrene-quinone, and on further bromination to 4, 9-(4, 10-) dibromo- 
 phenanthrene C 14 H 8 Br 2 , m.p. ii2 -ii3, which on oxidation yields 
 4-bromo-phenanthrene-quinone (A. 321, 330 ; B. 37, 3553). 
 
 Nitro-phenanthrenes. The nitration of phenanthrenes produces 
 three nitro-phenanthrenes, one of which has been found to be 3-nitro- 
 phenanthrene C ]4 H 9 [3]NO 2 , m.p. I7o-i7i (B. 34, 3532). If a mixture 
 of acetic anhydride and nitric acid is nitrified in glacial acetic acid we 
 obtain 9-nitro-phenanthrene, m.p. Ii6-ii7, which is also obtained 
 from the product of the action of gaseous nitrous acid upon phenan- 
 threne by treatment with sodium ethylate solution (B. 36, 2508). By 
 boiling with methyl-alcoholic potash the 9-nitro-phenanthrene takes 
 up two molecules CH 3 OK and transposes into the isomeric phenan- 
 threne-quinone-monoxime by way of phenanthrene-quinone-oxime- 
 dimethyl-acetal (A. 355, 307) : 
 
 H } 2 _ ^ ir H \ / C : NOK tc U\/ C: NOH 
 
 H )2 \CH (C6H4)2 \C(OCH 3 ) 2 - ^ (C6H * )2 \CO 
 
 Compare the similar transposition of 7-nitro-stilbene, of i- and 2-nitro- 
 naphthalene, and of 9-nitro-anthracene. 
 
 VOL. II. 2 Y 
 
690 ORGANIC CHEMISTRY 
 
 Amido-phenanthrenes, phenanthrylamines, have been obtained 
 partly by the reduction of the nitro-phenanthrenes, partly from the 
 phenanthrols by heating with ammonia salts : 2-amido-phenanthrene 
 C 14 H 9 (NH 2 ), m.p. 85, 3-amido-phenanthrene, m.p. 87 ; 9-amido- 
 phenanthrene, m.p. I35-I36, have also been obtained from the azide 
 of 9-phenanthrene-carboxylic acid (A. 321, 312 ; B. 34, 1461 ; 35, 
 
 2726). 9, 10-Diamido-phenanthrene 6 H 4 IIc NH 2 > from phenanthrene- 
 quinone-dioxime by reduction, gives by atmospheric oxidation diphen- 
 anthryl-azin C 14 H 8 : N 2 : C 14 H 8 (B. 35, 2738). 
 
 Phenanthrene-sulphonic Acids. On sulphurising phenanthrene 
 we obtain 3-, 2-, and 9-phenanthrene-sulphonie acids, C 14 H 9 .SO 3 H 
 (3-sulpho-chloride, m.p. 108, 2-sulpho-chloride, m.p. 156, Q-sulpho- 
 chloride, m.p. 125), whose constitution has been determined by con- 
 verting them into oxy- and cyano-phenanthrenes (A. 321, 251 ; 369, 
 104 ; 379, 79 ; B. 34, 4004). 
 
 xy-phenanthrenes , phenanthrols, have been obtained by fusion 
 with potash from the sulphonic acids and from the phenanthryl- 
 amines, while their ethers have also been obtained by the synthetic 
 methylated phenanthrene-g-carboxylic acids by rejection of CO 2 , 
 which has fixed the constitution of the five possible and known iso- 
 merides : 1-methoxy-phenanthrene C 14 H 9 -[i-](OCH 3 ), m.p. 106, 
 2-phenanthrol C 14 H 9 [2]OH, m.p. 168 (methyl ether, m.p. 99), 3- 
 phenanthrol, m.p. 124 (methyl ether, m.p. 63), 4-phenanthrol, m.p. 
 108 (methyl ether, m.p. 68), formed by nuclear synthesis on heating 
 /3-naphthyl iso-crotonic acid. 
 
 C* TT /"*TT /"* TT f*T-T 
 
 9-Phenanthrol, phenanthrone c^HcoH or tl\ Co 2 ' m 'P' I 53 > 
 is also formed by the reduction of phenanthraquinone with HI, or from 
 phenanthrene-quinone dichloride C 14 H S OC1 2 ; it gives, with diazo- 
 benzol salts, the 10-benzol-azo-9-phenanthrol, m.p. 165, which is identi- 
 cal with the product of the action of phenyl-hydrazin upon phenanthra- 
 quinone ; 2-, 3-, and 9-phenanthrol resemble j8-naphthol (A. 321, 276 ; 
 B. 34, 1461, 3998 ; 41, 4215). Of the amido-phenanthrols (A. 321, 
 286, 295) and the dioxy-phenanthrenes, the 9, lo-derivatives should 
 
 be separately mentioned. 9, 10-Amido-oxy-phenanthrene Ci2 H 8 \(4 N H , 
 from phenanthrene-quinone-oxime, -imine or phenyl-hydrazone, by 
 reduction easily passes into phenanthrene-hydroquinone, 9, lo-dioxy- 
 phenanthrene C 14 H g (OH) 2 , m.p. 147- 148, which is best formed by 
 reduction with zinc and glacial acetic acid, or with H 2 S in alcoholic 
 solution. Nitro-phenanthrene-hydroquinones have been obtained 
 similarly (B. 35, 3117). 
 
 3, 4-Dimethoxy-phenanthrene, dimethyl-morphol C 14 H 8 (OCH 3 ) 2 , 
 m.p. 44, from 9-carboxylic acid, or by methylating the corresponding 
 monomethyl-ether, methyl-morphol C 14 H 8 (OH)(OCH 3 ), which is a 
 product of the decomposition of the alkaloid codein (q.v.) (B. 33, 1816). 
 3, 4, 5-Trioxy-phenanthrene C 14 H 7 (OH) 3 , m.p. 148, is formed by 
 fusing morphinol with caustic potash (B. 39, 1718). 
 
 Phenanthrene-carboxylic Acids. Their nitriles have been obtained 
 from the salts of the sulphonic acids by distillation with potassium ferro- 
 cyanide. 9-Phenanthrene-carboxylic acid and its substitution pro- 
 
PHENANTHRENE GROUP 691 
 
 ducts have also been obtained synthetically by method 4 (above). 
 2-, 3-, and 9-Cyano-phenanthrene C 14 H 9 .CN, m.p. 105, 102, and 103 ; 
 2-, 3-, and 9-phenanthrene-carboxylic acids, m.p. 254, 269, and 250 
 (A. 321, 322). 8, 9-Phenanthrene-dicarboxylie acid, anhydride, m.p. 
 284, synthetically by method 4 (B. 39, 3115). 
 
 1-, 2-, 3-, and 4-Methoxy-phenanthrene-9-carboxylic acid C 14 H 8 
 (OCH 3 )CO 2 H, m.p. 215, 228, 239, and 224, and 3, 4-dimethoxy- 
 phenanthrene-g-carboxylic acid C 14 H 7 (OCH 3 ) 2 COOH, m.p. 228, from 
 the corresponding methoxy-amido-a-phenyl-cinnamic acids, split off 
 CO 2 on distillation and form methoxy-phenanthrenes (B. 34, 3998). 
 2,3- and 3, 2-Phenanthrol-carboxylic acid C 14 H 8 (OH).CO 2 H, m.p. 227 
 with decomposition and 303 with decomposition, have been obtained by 
 a salicylic acid synthesis by 2- and 3-sodium-phenanthrol by heating 
 with CO 2 under pressure. They are coloured yellow and resemble 
 2, 3-oxy-naphthoic acid (B. 35, 4419). 3, 4-Dimethoxy-phenanthrene- 
 8-carboxylic acid, m.p. 196, has been obtained from apo-morphin, a 
 transformation product of morphin (q.v.), by methylation and decom- 
 position (B. 40, 1998). 
 
 Hydro-phenanthrenes. By reduction of phenanthrene with sodium 
 and amyl alcohol, or by hydrogen in the presence of finely divided 
 nickel, colloidal platinum, or palladium, as well as heating with HI and 
 phosphorus, we obtain 9, 10-dihydro-phenanthrene C 14 H 12 , m.p. 94, 
 b -P- 313. Tetra-, hexa-, octo-, deca-, dodeca-, and per-hydro-phenan- 
 threne C 14 H 14 ,C 14 H 16 , C 14 H 18> C 14 H 20 , C 14 H 22 , and C 14 H 24 , b.p. 310, 306, 
 28o-285, 275, 269, and 27o-275 (B. 41, 1000, 4225 ; C. 1905, I. 
 1396 ; 1911, I. 651). 
 
 Derivatives of the 9, lo-dihydro-phenanthrene are found in the di- 
 tertiary glycols obtained by the action of alkyl- and aryl-magnesium 
 haloids upon phenanthraquinone ditertiary glycol : 9, 10-dimethyl-, 
 
 diethyl-, and diphenyl-9,10-dioxy-dihydro-phenanthrene ( C 
 
 m.p. 164, 122, and 179. By HI and phosphorus they are reduced 
 to 9, lo-dialkyl-phenanthrenes, and by chromic acid they are oxidised 
 
 to o, o'-diacyl-diphenylene ( C H )<Q3R> from which, by reduction, 
 the original glycols, or other stereo-isomeric forms, are regenerated. 
 On heating with dehydrating agents they undergo pinacolin transposi- 
 tion and form 10, 10-dialkyl-phenanthrones (C 6 H 4 ) a <^^ , (?) 10, 10- 
 
 dimethyl-, diethyl-, and diphenyl-phenanthrone, m.p. 75, 65, and 198, 
 (cp. also 10, lo-Diphenylene-phenanthrone) (A. 362, 242 ; B. 37, 2887 ; 
 C. 1905, I. 878). 
 
 Phenanthraquinone (C 6 H 4 ) 2 (CO) 2 is formed in the action of chromic 
 acid upon phenanthrene in glacial acetic acid solution ; most readily 
 by heating it with a chromic acid mixture (A. 196, 38). It crystallises 
 in long, orange-yellow needles, melts at 198, and distils without decom- 
 position. It dissolves readily in hot alcohol, ether, and benzene, but 
 sparingly in water. It dissolves in concentrated sulphuric acid with a 
 dark-green colour, and is reprecipitated by water. By adding toluene 
 containing thiotolene and sulphuric acid to the acetic acid solution 
 of phenanthraquinone a bluish-green coloration is produced (see 
 Thiophenc). 
 
 In behaviour it recalls /3-naphtho-quinone. It is odourless, not 
 
692 ORGANIC CHEMISTRY 
 
 volatile in steam, unites with one and two molecules of hydroxylamine, 
 and is not reduced by sulphuric acid. 
 
 Phenanthraquinone-monoxime C 14 H 8 O(N.OH) consists of golden- 
 yellow needles, melting at 158. If it is heated together with glacial 
 acetic acid and hydrochloric acid to 130 it sustains the transposition 
 of ketoximes, and forms diphenimide (B. 21, 2356) : 
 
 C 6 H 4 C : NOH C 6 H 4 CO 
 
 I I > I 
 
 C 6 H 4 CO C 6 H 4 CO 
 
 ^N. 
 
 The dioxime forms an anhydride C 14 H 8 ^ No, melting at 181. 
 
 This is a furazane derivative. 
 
 The monophenyl-hydrazone of phenanthraquinone is identical with 
 
 /C.OH 
 the 9, lo-benzol-azo-phenanthrol (C 6 H 4 ) 2 <( j| . Also, the acyl- 
 
 X C.N : NC 6 H 5 
 
 phenyl-hydrazones obtained by the transformation of as-acetyl- 
 and benzoyl-phenyl-hydrazin with phenanthraquinones pass spontane- 
 ously into the isomeric O-acyl-compounds of 9, lo-benzol-azo-phen- 
 anthrol (A. 378, 211). 
 
 Phenanthraquinone, being an o-diketone, forms phenazin deriva- 
 tives with o-diamines. See B. 24, R. 630, 631, for the condensations of 
 aceto-acetic ester and acetone. By oxidation with chromic acid, or 
 by boiling with alcoholic potash, phenanthraquinone is oxidised to 
 diphenic acid ; ignition with soda-lime produces diphenylene-ketone, 
 fluorene, and diphenyl. Diphenylene-gly collie acid, fluorene alcohol, 
 and diphenylene-ketone are obtained on boiling with aqueous soda-lye. 
 Ignition with zinc dust produces phenanthrene. 
 
 By sulphurous acid, or hydrogen sulphide, it is reduced to phen- 
 anthrene-hydroquinone, by HI to phenanthrone. With HI and phos- 
 phorus in glacial acetic acid we obtain aceto-phenanthrene-hydro- 
 quinones C 14 H 8 (OH)(OCOCH 3 ), m.p. 78 (B. 26, R. 585 ; C. 1897, II. 
 1072). Mixtures of phenanthrene and quinone in sunlight give acidyl- 
 phenanthrene-hydroquinones (A. 249, 137). With phenol it can be 
 condensed to phenoxy-phenanthrene-hydroquinone (C. 1900, II. 360). 
 
 Bromine acts upon phenanthrene-quinone at low temperatures with 
 formation of an addition product C 14 H 8 O 2 Br 2 (B. 37, 3556). At 100 
 substitution products are formed : 2-bromo- and 2, 7-dibromo-phen- 
 anthrene-quinone, m.p. 234 and 323. 3- and 4-bromo-phenanthrene- 
 quinone, m.p. 286 and 126, have been obtained from 3, 9- and 4, 9- 
 dibromo-phenanthrene ; 2-chloro-phenanthrene-quinone, m.p. 236, 
 from 2, 9, lo-trichloro-phenanthrene by oxidation with CrO 3 (B. 37, 
 355i; 39,3893). 
 
 By heating with nitric acid, phenanthrene-quinone is converted into 
 2- and 4-nitro-phenanthrene-quinone C 14 H 7 (NO 2 )O 2 , m.p. 257 and 
 180, and after prolonged action into 2, 7- and 4, 5-dinitro-phen- 
 anthrene-quinone C 14 H 6 (NO 2 ) 2 O 2 , m.p. 3oo-3O3 and 228. 3-Nitro- 
 phenanthrene-quinone, m.p. 275, is formed from g-bromo-phenan- 
 threne, as well as from 9, lo-diacetamido-phenanthrene with nitric acid 
 (B. 41, 3679). By oxidation with chromic acid mixture nitro-phen- 
 anthrene-qui nones yield nitro-diphenic acids ; by means of reduction, 
 amido-phenanthrene-quinones have been obtained, and from tnese oxy- 
 
PHENANTHRENE GROUP 693 
 
 phenanthrene-quinones (B. 36, 3726 ; A. 322, 135). The latter also 
 result from acidulated phenanthrols by oxidation with CrO 3 : 3-oxy- 
 phenanthrene-quinone C 14 H 7 (OH)O 2 , in needles resembling alizarin and 
 capable of sublimation ; 2-oxy-phenanthrene-quinone, dark violet 
 needles, m.p. 28o-283 ; 4-oxy-phenanthrene-quinone, red powder, 
 m.p. 285 (B. 44, 740). 3, 4-Dioxy-phenanthrene-quinone, morphol- 
 quinone C 14 H 6 (OH) 2 O 2 (diaceto-compound, m.p. 196) has been ob- 
 tained from 3-oxy-phenanthrene-quinone by way of the nitro- and 
 amido-compounds (B. 41, 3696). 
 
 3-Phenanthrene-quinone-sulphonie acid C 14 H 7 O 2 (SO 3 H) from 3- 
 phenanthrene-sulphonic acids with CrO 3 (A. 321, 339). 
 
 Retene or l-methyl-7-iso-propyl-phenanthrene 
 
 :H3[l]CeH3 \CHTcEp C ' H3[73C3H7 ' melting at 98 and boiling at 394, is 
 a homologue of phenanthrene. 
 
 Retene occurs in the tar of highly resinous pines, and in some 
 mineral resins. It is isolated from those portions that boil at elevated 
 temperatures. 
 
 It results from the distillation of abietic acid (probably a deka- 
 hydro-retene-carboxylic acid) with sulphur (B. 36, 4200). Its picrate 
 forms orange-yellow needles, melting at 123. Chromic acid in glacial 
 acetic acid solution oxidises retene to retene-quinone C 18 H 16 O 2 (methyl- 
 iso-propyl-phenanthraquinone), melting at 197. It resembles phen- 
 anthraquinone in its entire behaviour. Sodium hydrate converts 
 retene-quinone into : 
 
 Retene-diphenic acid C^I^CQ'H and retene-glycollic acid C 16 H 16 . 
 C(OH).CO 2 H. Potassium permanganate oxidises retene-quinone to 
 retene -ketone C 
 
 lene-ketone-i-carboxylic acid CO 2 H[i 3 C < H 3 ^-- 7 C 6 H 3 [ 7 ]C(OH)(CH 3 ) 2 
 
 diphenylene-ketone-i, y-dicarboxylic acid co 
 
 the latter, in turn, passing into a mixture of 1,2, 3- and i, 2, 4-benzol- 
 tricarboxylic acid. The 7-oxy-iso-propyl-diphenylene-ketone-i-car- 
 boxylic acid can be broken down to p-iso-propyl-diphenyl C 6 H 5 .C 6 H 4 
 [4]C 3 H 7 by means of KOH, reduction with HI, and rejection of the 
 carboxyls, which proves the position of the side-chains in retene (C. 
 1910, I. 1530). 
 
 Retene dodeca-hydride, dehydro-fichtelite C 18 H 30 is an oil, boiling at 
 336. It is formed when retene is heated with hydriodic acid and phos- 
 phorus to 250, and also in the action of iodine upon fichtelite C 18 H 32 , 
 melting at 46, which occurs, together with retene, in the peat of fossil 
 plants (B. 22, 498, 635, 780, 3369). 
 
 Chrysene and picene possess a structure similar to that of phenan- 
 threne. They can be derived from phenyl-naphthalene and dinaphthyl 
 the same as phenanthrene from diphenyl : 
 
 C 6 H 4 CH C 6 H 4 CH C 10 H 8 CH 
 
 C 6 H 4 CH C 10 H 6 CH C 10 H 6 CH 
 
 I Phenanthrene Chrysene Picene. 
 
 The constitution of these bodies is deduced mainly from the pro- 
 
694 ORGANIC CHEMISTRY 
 
 ducts of their oxidation. Chromic acid first changes them to chryso- 
 quinone and piceno-quinone, which can be further transposed into 
 chrysene- and picene-ketones, chrysenic acid and picenic acid, j3-phenyl- 
 naphthalene and jS-dinaphthyl : 
 
 C 6 H 4 . CO C 6 H 4X C 6 H 5 C 6 H 5 
 
 C 10 H 6 CO Ci H 6 / C 10 H 6 .COOH C 10 H 7 
 
 Chryso-quinone Chrysene- ketone Chrysenic acid /5-Phenyl-naphthalene. 
 
 c io H e CO C 10 H 6 , C 10 H 7 C 10 H 7 
 
 C 10 H 6 CO C 10 H/ C 10 H 6 .COOH C 10 H 7 
 
 Piceno-quinone Picene-ketone Picenic acid /S-Dinaphthyl. 
 
 Chrysene C 18 H 12 , m.p. 250 and b.p. 448, consists, in a pure con- 
 dition, of silver-white flakes with a violet fluorescence. When impure 
 it has a yellow colour (hence the name from ^pucreo?, gold-yellow). 
 It occurs in those portions of coal-tar which have high boiling-points. 
 It can be synthesised from phenyl-naphthyl-ethane C 6 H 5 .CH 2 .CH 2 . 
 C 10 H 7 , just as phenanthrene is produced from dibenzyl ; also by heat- 
 ing naphthalene with cumarone. It is formed in large quantities by 
 heating indene 2C 9 H 8 C 1Q H 12 +4H (B. 26, 1544). See B. 24, 949, for 
 substituted chrysenes. The hydrides, C 18 H 28 , b.p. 360, and C 18 H 30 , 
 m.p. 115 and b.p. 353 (B. 22, 135), result upon heating chrysene with 
 hydriodic acid and phosphorus. 
 
 When digested with chromic acid and glacial acetic acid chrysene 
 oxidises to so-called chryso-quinone C 18 H 10 O 2 (a diketone), which cry- 
 stallises in red needles, melting at 235. 
 
 Chryso-ketone C 17 H 10 O results when chryso-quinone is distilled with 
 lead oxide. Hydriodic acid and phosphorus reduce it to chryso-fluorene 
 C 17 H 12 . 
 
 On boiling with permanganate, chrysene-qumone, and chrysene- 
 ketone even more readily, give diphthalic acid COOHC 6 H 4 CO.COC 6 H 4 
 COOH. On heating with soda-lime or potash and PbO 2 , chrysene- 
 quinone yields chrysenic acid or jS-phenyl-a-naphthoic acid, which by 
 rejection of CO, yields fi-phenyl-phthalin (B. 26, 1745). A transposi- 
 
 7 C : NOH 
 
 tion of chrysene-quinone-oxime C 16 H 10 / | , m.p. 161, produces 
 
 CO 
 
 at 100 two isomeric amido-acids C 16 H 10 <^ , m.p. 220 and 
 
 C 6 H 4 COOH 
 
 275, which on saponification give chryso-diphenic acid I 
 
 C 10 H 6 COOH 
 m.p. 199, and, in the manner of diphenaminic acid, are converted by 
 
 sodium hypochlorite into a- and jS-naphthanthridone ^^ 6 CO , m.p. 
 
 332, and ^ 6 N C H > m.p. 338 (A. 311, 257 ', 335, 124 ; B. 35, 2744). 
 
 Picene C 22 H 14 is the hydrocarbon with the highest melting-point 
 (364) . It is formed by the distillation of lignite, coal-tar, and petroleum 
 residues. It can be synthesised from naphthalene and ethylene 
 bromide by means of A1C1 3 (B. 24, R. 963 ; 32, 3341 ; C. 1910, II. 471). 
 It is very sparingly soluble in most solvents, but most readily in crude 
 cymol. When heated to 250 with hydro-iodic acid and phosphorus, 
 
FLUORENE GROUP 695 
 
 picene-perhydride C 22 H 36 is produced. It melts at 175. Picene is 
 oxidised by chromic acid to an orange-red quinone C 22 H 12 O 2 , which, 
 like chrysene, is changed on the one hand to picene-ketone, picene- 
 fluorene alcohol, and picene-fluorene (C 10 H 6 ) 2 CH 2 , and on the other to 
 picenic acid or dinaphthyl-carboxylic acid and j3-dinaphthyl (B. 26, 
 
 Pyrene C 16 H 10 , lemon-yellow plates, m.p. 149, b.p. 60 260 ; picrate, 
 m.p. 222 ; it is converted, by chromic acid in glacial acetic acid, into 
 pyrene-quinone C 16 H S O 2 , and on further oxidation to pyrenic acid 
 C 12 H 6 (CO)(COOH) 2 (M. 31, 861), a ketone-dicarboxylic acid which 
 easily shows anhydride and imide formations (B. 19, 1997), and, on 
 distillation, produces pyrene-ketone C 12 H S (CO), m.p. 141. On oxidis- 
 ing pyrenic acid with MnO4K, we obtain i, 4, 5, 8-naphthalene-tetra- 
 carboxylic acid, and from pyrene-ketone naphthalic acid. On the 
 constitutions of pyrene, as one of the ring systems consisting of four 
 condensed benzene nuclei, see B. 20, 365 ; A. 351, 218. 
 
 Triphenylene ^ 6 2 4 '^~ S = 2, white needles, m.p. 198, is formed 
 
 L, 6 rl 4 .C Crl = Crl 
 
 on conducting benzene vapours through incandescent tubes. Fuming 
 nitric acid oxidises it to mellithic acid. A dodeca-hydro-triphenylene 
 Ci 8 H 24 , m.p. 233, is formed by the condensation of cyclo-hexanone 
 with alcoholic H 2 SO 4 , as mesitylene from acetone (B. 40, 153). See 
 also tricyclo-trimethylene benzol C 15 H 1S , m.p. 96 (B. 30, 1094). 
 
 IV. FLUORENE GROUP. 
 
 Just as phenanthrene, chrysene, and picene were regarded as sym- 
 metrical o 2 -ethylene derivatives of diphenyl, phenyl-naphthyl, and 
 dinaphthyl, so fluorene, chrysene-fluorene, and picene-fluorene may be 
 viewed as o 2 -methylene derivatives of the last-mentioned hydrocarbons, 
 and accordingly may be designated diphenylene-methane, phenylene- 
 naphthylene, and dinaphthylene-methanes. On the other hand, they can, 
 like indene, be regarded as condensed cyclo-pentadiene derivatives : di- 
 benzo-, benzo-naphtho-, and dinaphtho-cyclo-pentadiene. Fluorene 
 is also closely allied to diphenylene oxide, diphenylene sulphide, and 
 diphenylene-imide or carbazol (q.v.), dibenzo-derivatives of furfurane, 
 thiophene, and pyrrol : 
 
 CH 2 
 t,H/ 
 Fluorene 
 
 ?' H > 
 
 C.H/ 
 Diphenylene 
 oxide 
 
 1 ' *\S 
 
 Diphenylene 
 sulphide 
 
 1 ' 4 \NH 
 C.H/ 
 
 Diphenylene- 
 imide. 
 
 General Methods of Formation. I. Fluorene is formed by con- 
 ducting vapours of diphenyl-methane through tubes heated to redness ; 
 chryso-fluorene is similarly obtained from j8-naphthyl-phenyl-methane : 
 
 \CH,X 
 
 2. o-Diphenyl-carboxylic acid, phenyl-naphthyl-carboxylic acid or 
 chrysenic acid, and dinaphthyl-carboxylic or picenic acid, when heated 
 alone or in the form of salts, yield fluorene-, chrysene-, and picene- 
 
696 ORGANIC CHEMISTRY 
 
 ketones, which can be readily reduced to fluorene, chryso-fluorene, and 
 picene-fluorene ; conversely, the acids are reformed when the ketones 
 are fused with caustic potash : 
 
 C 6 H 4 .COOH - > C 6 H 4x 
 
 | \CO. 
 
 C 6 H 5 --- C 6 H/ 
 
 3. Fluorene-ketone is also obtained from the diazo-derivative of 
 o-amido-benzo-phenone by the elimination of nitrogen ; similarly, 
 chrysene-ketone is formed from o-amido-phenyl-a-naphthyl-ketone 
 (B. 29, 826) : 
 
 C 6 H 4 N 2 OHC 6 H 5 - > C 6 H 4 ___ C 6 H 4 . 
 
 4. Phenanthraquinone, chryso-quinone, and piceno-quinone, when 
 oxidised, also yield the ketones of the corresponding fluorenes : 
 
 C 6 H 4 CO C 6 H 4 
 
 C 6 H 4 CO ^C 6 H/ 
 
 Fluorene, diphenylene-methane C 13 H 10 , m.p. 113 and b.p. 295, 
 crystallises in colourless leaflets with a violet fluorescence. It forms 
 a compound with picric acid, melting at 81. 
 
 It is found in coal-tar (fraction 27O-3OO) ; on heating with sodium 
 or sodium amide to I2o-I5o, it forms a sodium salt (C 6 H 4 ) 2 : CHNa, 
 by means of which it can be detached from the accompanying hydro- 
 carbons (B. 41, 2913). 
 
 It results upon exposing diphenyl-methane to a high temperature 
 (above), and in the reduction of diphenylene-ketone with zinc dust or 
 upon heating it to 160 with HI and phosphorus. The chromic acid 
 mixture oxidises it to diphenylene-ketone. 
 
 In fluorene the hydrogen atoms of the CH 2 group are mobile as in 
 cyclo-pentadiene and indene, but to a less extent. Heating with caustic 
 potash and benzyl chloride forms dibenzyl-fluorene (C 6 H 4 ) 2 C(CH 2 C 6 H 5 ) 2 , 
 m.p. 148 ; with benzaldehyde, cinnamic aldehyde, etc., it condenses to 
 colourless or faintly coloured benzylidene-fluorene (C 6 H 4 ) 2 C : CHC 6 H 5 , 
 m.p. 76, and cinnamylidene-fluorene (C 6 H 4 ) 2 C : CH.CH : CHC 6 H 5 , 
 m.p. 154 ; with oxalic ester to fluorene-oxalic ester (C 6 H 4 ) 2 CHCOCO 2 
 C 2 H 5 , m.p. 75 ; with formic ester to formyl-fluorene or diphenyl- 
 acetaldehyde (C 6 H 4 ) 2 CH.CHO, m.p. about 70 (B. 43, 2719) ; with 
 amyl nitrite and ethyl nitrate under the influence of potassium ethylate 
 free from alcohol, it yields fluorenone-oxime (C 6 H 4 ) 2 C : NOH and 
 9-nitro-fluorene (C 6 H 4 ) 2 CHNO 2 respectively, which, like phenyl-nitro- 
 methane, occurs in an acid form soluble in alkalies, m.p. 135, and a 
 neutral form, insoluble in alkalies, m.p. 182 (A. 347, 290 ; B. 33, 852 ; 
 
 41, 3334). 
 
 By reduction of fluorene with HI and phosphorus, or hydrogen and 
 nickel, we obtain perhydro-fluorene C 13 H 22 , b.p. 256-258, D 22 0-9203 
 (B. 42, 920, 2093). The isolation of a hexahydro-fluorene C 13 H 16 , 
 from coal, by extraction with benzene, or distillation in a vacuum, is 
 noteworthy (B. 44, 2486). 
 
 By bromination of fluorene in boiling chloroform we obtain 2, 7- 
 dibromo-fluorene C 13 H,Br 2 , m.p. 164, and 2, 6(?), 7-tribromo-fluorene 
 
FLUORENE GROUP 697 
 
 C 13 H 7 Br 3 , m.p. 200 (B. 38, 3764). g-Chloro-fluorene C 13 H 9 C1, m.p. 90 
 from fluorene alcohol with PC1 5 (B. 37, 2896). 
 
 Nitration of fluorene in glacial acetic acid produces 2-nitro-fluorene 
 NO 2 C 13 H 9 , m.p. 153, which, by known methods, can be converted 
 into 2-amidb-diazo- and oxy-fluorene and 2-fluoryl-hydrazin. Nitration 
 of the 2-acetamido-fluorene produces 2, 7- and 2, 1-amido-nitro- 
 fluorene, m.p. 232 and 206, which produce 2, 7- and 2, 1-diamido- 
 fluorene, m.p. 164 and 193 (B. 34, 1758 ; 35, 3284) ; 9-amido- 
 fluorene, two modifications, m.p. 54 and 123, by reduction of fluorenone 
 oxime (B. 41, 1243). 
 
 Retene - fluorene, i - methyl - 7 - iso - propyl - diphenyl - methane 
 
 ,H 3 )CjH 3 NcH 2 , melting at 97, is derived from its ketone upon dis- 
 (C3H 7 )C 6 H 3 / 
 
 tillation with zinc dust . Chry so-fluorene , naphthylene-phenylene-methane 
 C IO H 6 CH 2 C 6 H 4 , melting at 180, is erived from j3-benzyl-naphtha- 
 lene or from chryso-ketone. An iso-naphtho-fluorene ff^p H ffi^>cH 2> 
 
 m.p. 208, has been obtained from iso-naphtho-fluorenone (A. 376, 276 ; 
 B. 27, 953). Picene-fluorene, picylene-methane (C 10 H 6 ) 2 CH 2 , melting 
 at 306, is produced on heating its ketone to i6o-i75 with hydriodic 
 acid (A. 284, 70). 
 
 This is isomeric with the aa- and j8j3-dinaphtho-fluorene, m.p. 236 
 and 186, obtained from aa- and j3j3-dinaphthyl carbinol (B. 43, 2832). 
 
 Methyl-hexahydro-fluorene, boiling at 128 (14 mm.), results from 
 the action of P 2 O 5 upon methyl-benzyl-cyclo-hexanol, the reduction 
 product of benzylidene-methyl-cyclo-hexanone (CH 3 )(OH)C 6 H 9 : CH 2 . 
 
 C 6 H 5 -- > (CH 3 )C 6 H 9 .CH 2 .C 6 H 4 (B. 29, 2962 ; A. 305, 264). 
 
 Diphenylene-phenyl-methane, phenyl- fluorene (C 6 H 4 ) 2 CHC 6 H 5 , melt- 
 ing at 146, results (i) on heating triphenyl-methane chloride (C 6 H 5 ) 3 CC1, 
 or potassium-triphenyl-methane ; (2) from triphenyl-carbinol by dis- 
 tillation with crystallised phosphoric acid ; (3) from fluorene alcohol, 
 benzene-sulphuric acid ; (4) from 9-chloro-fluorene, benzene, and A1C1 3 
 (5) from hydro-fluoranic acid by distillation over soda-lime ; and (6) 
 by reduction of diphenylene - phenyl - carbinol, 9 - phenyl -fluorenol 
 
 C^ T-T \. /^~\TT 
 
 , 6 */C^ , m.p. 107. The latter, analogous to triphenyl-carbinol, 
 
 is obtained from diphenylene-ketone with phenyl-magnesium bromide, 
 or by oxidation of 9-phenyl-fluorene with chromic acid ; it gives 
 intensely coloured double salts and perchlorate ; with aniline chloro- 
 hydrate it condenses to diphenylene-p-amido-diphenyl-methane 
 (C 6 H 4 ) 2 C(C 6 H 5 )C 6 H 4 NH 2 , m.p. 179 ; with phenol and sulphuric acid 
 to diphenylene-p-oxy-diphenyl-methane, m.p. 191 (B. 37, 73). By 
 the action of PC1 5 , acetyl chloride, or gaseous HC1, it passes into 9, 9- 
 phenyl-chloro-fluorene (C 6 H 4 ) 2 CC1C 6 H 5 , m.p. 79, which, like triphenyl- 
 chloro-methane, is distinguished by the mobility of its chlorine atom. 
 By heating with copper powder in benzene solution it passes into 
 di-biphenylene-diphenyl-ethane (C 6 H 4 ) 2 (C 6 H 5 )C.C(C 6 H 5 ) (C 6 H 4 ) 2 , m.p. 
 254. This forms colourless crystals which dissolve colourless in the 
 cold, and only assume a dark-brown colour on heating, with partial 
 decomposition into two molecules biphenylene-phenyl-methyl (^6^-4)2 
 C(C 6 H 5 ). In the air it absorbs oxygen, and accordingly passes into 
 
698 ORGANIC CHEMISTRY 
 
 the corresponding peroxide, m.p. 193. Still more stable is the 
 analogous body di-biphenylene-di-biphenyl-ethane (C 6 H 4 ) 2 (C 6 H 5 .C 6 H 4 )C. 
 C(C 6 H 4 .C 6 H 5 )(C 6 H 4 ) 2 , m.p. 176, obtained from 9, 9-biphenyl-chloro- 
 fluorene (C 6 H 4 ) 2 CC1C 6 H 4 .C 6 H 5 , m.p. 139, which only undergoes a 
 slight dissociation in boiling anisol and is insensitive to oxygen, both 
 in solution and in the solid state (A. 372, 21 ; B. 43, 1753). 
 
 Phenyl-chryso-fluorene 5 1 ^ > ScHC t H i , m.p. 195, from diphenyl-a- 
 
 t - / 6"4 ' 
 
 naphthyl-carbinol with concentrated SO 4 H 2 or ZnCl 2 (B. 38, 2215) ; 
 9, 9-diphenyl-fluorene (C 6 H 4 ) 2 C(C 6 H 5 ) 2 , m.p. 220, analogous to 
 diphenyl-monobiphenyl-carbinol (B. 38, 4105). 
 
 Diphenylene-diphenyl-ethane (C 6 H 4 ) 2 CH.CH(C 6 H 6 ) 2 , melting at 
 217, and diphenylene-diphenyl-ethylene (C 6 H 4 ) 2 C : C(C 6 H 5 ) 2 , melting 
 at 229, arise in the breaking-down of diphenylene-diphenyl-succinic 
 
 anhydride , " * \ r r^' mel: :1 & at 2 5 6 one * tne reaction products 
 
 of cold concentrated sulphuric acid upon benzilic acid. Diphenylene- 
 diphenyl-ethylene is produced on heating benzo-phenone chloride with 
 fluorene. It consists of colourless crystals, the solutions of which are 
 coloured intensely yellow. The moderated oxidation of this body with 
 chromic acid gives rise to 9, 9-benzoyl-phenyl-fluorene (C 6 H 4 ) 2 C(C 6 H 5 ) 
 COC 6 H 5 , m.p. 172, by pinacolin transformation from the pinacone 
 first formed. It is also obtained from potassium-triphenyl-methane, 
 or potassium-9-phenyl-fluorene with benzoyl chloride. Alcoholic 
 potash breaks it up into 9-phenyl-fluorene and benzoic acid. By 
 reduction with HI and phosphorus, benzoyl-phenyl-fluorene is converted 
 into 9, lo-diphenyl-phenanthrene, with reversal of the pinacolin trans- 
 position and expansion of the ring (B. 37, 2887). 
 
 Bi-diphenylene-ethane (C 6 H 4 ) 2 CH.CH(C 6 H 4 ) 2 , colourless needles, 
 melting at 246, is produced, together with bi-diphenylene-ethylene, 
 bifluorene (C 6 H 4 ) 2 C : C(C 6 H 4 ) 2 , melting at 188, on heating fluorene 
 with lead oxide. The second hydrocarbon is also formed on heating 
 fluorene with bromine, chlorine, or sulphur, and by the action of 
 alcoholic potash upon 9-bromo-fluorene (A. 376, 271) ; or of copper 
 powder upon fluorene dichloride (B. 43, 1796). 
 
 It consists of beautiful r^-coloured needles. Its bromine addition 
 product is colourless, and when heated with sodium in xylene solution 
 it reverts to the red hydrocarbon (B. 25, 3140 ; A. 290, 238 ; 291, i). 
 The following diagram is interesting from the point of view of the 
 colour of highly condensed hydrocarbons : 
 
 C.H C.H. C.H C.H, C,H 
 
 Tetraphenyl-ethylene. Diphenylene-diphenyl-ethylene. Bi-diphenylene-ethy- 
 Colourless Colourless ; yellow in solution lene. Red needles. 
 
 Compare the yellow colour of acenaphthylene and the red colour of 
 diphenyl-fulvene. On oxidation with chromic acid the di-biphenylene- 
 ethylene forms, by a change analogous to the pinacolin trans- 
 position, besides fluorenone, a 10, 10 - diphenylene - phenanthrone 
 
 (C 6 H 4 ) 2 : C C 6 H 4 
 
 I I (?), m.p. 258, which is broken up by alcoholic 
 OC C 6 H 
 
FLUORENE GROUP 699 
 
 potash to form the acid (C 6 H 4 ) : CH-C 6 H 4 .C 6 H 4 COOH. The same 
 pinacolin is also formed in the reduction of fluorenone with zinc dust 
 and acetyl chloride. It is probably identical with the so-called di-bi- 
 phenylene-ethylene oxide obtained from di-biphenylene-ethylene 
 dibromide by heating with water. By reduction with HI it is trans- 
 
 f TT CT-T f* T-T 
 
 formed into 9, 10-diphenylene-phenanthrene ^ 6 H * ^ H '^' F ' ( ? ) m -P- 
 
 215, with another transposition (B. 29, 2152 ; 37, 2894 ; A. 291, i). 
 
 Fluorene alcohol, fluorenol (C 6 H 4 ) 2 CHOH, m.p. 153, is formed from 
 the ketone with Na amalgam and from the Na salt of diphenyl-gly colic 
 acid by heating to 120. Like fluorene alcohol, retene, picene, and 
 chrysene-fluorene alcohols, m.p. 134, 167, and 230, are obtained. 
 Fluorene ether [(C 6 H 4 ) 2 CH] 2 O, m.p. 228, from 9-chloro-fluorene and 
 Ag 2 O (B. 43, 2490). Methyl-, ethyl-, and benzyl-fluorenol (C 6 H 4 ) 2 
 C(OH)R, m.p. 174, 101, and 139, are formed from fluorenone with 
 the corresponding alkyl Mg haloids (B. 38, 4105). 
 
 Diphenylene-ketone, fluorenone \ 6 I* >CO, melting at 84 and boiling 
 
 C 6 H 4 / 
 
 at 341 (B. 27, R. 641), is obtained from diphenic acid, iso-diphenic acid, 
 and o-diphenyl-carboxylic acid when heated with lime ; by oxidising 
 fluorene with a chromic acid mixture, and by heating phenanthra- 
 quinone with caustic lime (A. 196, 45 ; 279, 257), and when the diazo- 
 compound of o-amido-benzo-phenone is heated with water (B. 28, in). 
 Potassium permanganate oxidises it to phthalic acid. It is converted 
 into o-phenyl-benzoic acid on fusion with potassium hydroxide. Its 
 oxime (C 6 H 4 ) 2 C : NOH melts at 193 ; the phenyl-hydrazone melts at 
 151 (B. 29, 230, R. 26). 
 
 Retene-ketone (C 3 H 7 )(CH 3 )(!: 6 H 2 .CO.C 6 H 4 melts at 90. Chryso- 
 
 ketone, naphtho-fluorenone C 6 H 4 .CO.C 10 H 6 , melts at 130. On the 
 formation of the latter from o-amido-phenyl-a-naphthyl-ketone, see 
 above. An iso-naphtho-fluorenone, m.p. 152, has been obtained by 
 condensation from o-phthalaldehyde with a-hydrindone by means of 
 K methylate (A. 376, 269). Picene-ketone (C 10 H 6 ) 2 CO, m.p. 185 ; 
 aa- and /3/3-dinaphtho-fluorenone, m.p. 225 and 161, from the cor- 
 responding dinaphtho-fluorenes (B. 43, 2833). 
 
 With concentrated HNO 3 in the cold, fluorenone yields a loose 
 addition product (C 6 H 4 ) 2 CO.NO 3 H, which easily separates into its 
 components. Energetic nitration gives 2, 7-dinitro- and 2, 6, 7-trinitro- 
 fluorenone, m.p. 290 and 181 respectively (B. 38, 3758). 
 
 o-Oxy-diphenylene-ketone, oxy-fluorenone C 6 H 3 (OH).CO.C 6 H 4 , melt- 
 ing at 115, is obtained from sym. o-diamido-benzo-phenone on boil- 
 ing its diazo-salts with water, together with xanthone (B. 31, 3034) ; 
 and from 1-amido-diphenylene-ketone, m.p. 110, obtained from di- 
 phenylene-ketone-i-carboxylic amide with KOBr (C. 1902, II. 1472). 
 The i -oxy-fluorenone forms yellowish-red or dark-red alkali salts, 
 showing feeble drying properties. 
 
 When fused with caustic potash it decomposes into o-phenyl- 
 salicylic acid C 6 H 5 .C 6 H 3 (OH)COOH, which is recondensed by concen- 
 trated sulphuric acid to oxy-diphenylene-ketone (B. 23, 112). 4~Oxy- 
 diphenylene-ketone is also prepared from 4-amido-diphenylene-ketone, 
 
700 ORGANIC CHEMISTRY 
 
 melting at 138, which is obtained from diphenylene-ketone-carboxyl- 
 amide with bromine and caustic potash. 
 
 By fusing with potash the 4-amido-fluorenone is transformed into 
 phenanthridone (B. 28, R. 455), which also results by Beckmann's 
 transposition on heating the oxime of fluorenone with zinc chloride 
 (B. 29, 230) : 
 
 C 6 H 3 (NH 2 ) CO C G H 4 > C 6 H 4 NH CO C H 4 < C 6 H 4 C(NOH) C 6 H 4 
 
 4-Amido-fluorenone Phenanthridone Fluorenone-oxime. 
 
 2-Amido-fluorenone, m.p. 163, from 2-nitro-fluorenone, m.p. 222- 
 223, the oxidation product of 2-nitro-fluorene, by reduction with 
 Am 2 S, gives with the diazo-salts 2-oxy-fluorenone, m.p. 2io-2ii 
 (B. 34, 1764). 3-Oxy-fluorenone, m.p. 229, is formed from synthetic 
 3-oxy-fluorenone-4-carboxylic acid by splitting off CO 2 . 
 
 Carboxylic Acids. Diphenylene-acetic acid, fluorene-carboxylic acid 
 (C 6 H 4 ) 2 CH.CO 2 H, melting at 221, results on reducing diphenylene- 
 glycollic acid with hydriodic acid and phosphorus. Also from trichlor- 
 acetic ester with benzene and A1C1 3 (C. 1902, II. 991). Its nitrile, 
 m.p. 152, is formed from diphenylene-acetaldoxime with acetyl 
 chloride. 
 
 Diphenylene-glycollie acid, ms-oxy-fluorene-carboxylic acid (C 6 H 4 ) 2 
 C(OH).CO 2 H, melting at 162, is produced when phenanthraquinone 
 is boiled with sodium hydroxide. In this instance an atomic rearrange- 
 ment occurs, similar to that observed in the transition of benzile to 
 benzilic acid, or of j8-naphtho-quinone to oxy-indene-carboxylic acids : 
 
 CgHgCO H.O C 6 H 5V C 6 H 4 CO HO C 6 H 4x 
 
 I *+ \C(OH).COOH | I --* I \C(OH)COOH. 
 
 C 6 H 5 CO C 6 H/ C 6 H 4 CO C 6 H/ 
 
 Chromic acid oxidises it to diphenylene-ketone. Analogues of 
 diphenylene-glycollic acid have been obtained from retene- and 
 chrysene-quinone (above), and from other substituted phenanthrene- 
 quinones (B. 38, 3737). With phenols and phenol ethers diphenylene- 
 glycollic acid condenses in the manner of benzilic acid, under the in- 
 fluence of tin tetrachloride, to form substituted diphenylene-phenyl- 
 acetic acids (B. 43, 2496). With PC1 5 it forms diphenylene-chloro- 
 acetic-acid chloride, m.p. 112, which, on treatment with zinc chips in 
 ether solution, passes into diphenylene-ketene (C 6 H 4 ) 2 C : CO, golden- 
 yellow spears, m.p. 90, an analogue of diphenyl-ketene (B. 39, 3062). 
 
 Fluorene-oxalic acid (C 6 H 4 ) 2 CH.COCOOH+H 2 O, m.p. I5o-i5i, 
 decomposes on heating into CO, CO 2 , and fluorene ; its esters, formed 
 from fluorene, oxalic ester, and sodium, give, with Na alcoholate and 
 ICH 3 or IC 2 H 5 , methyl- and ethyl-fluorene-oxalic esters, and, by splitting 
 up the latter, 9-methyl-fluorene (C 6 H 4 ) 2 CHCH 3 , m.p. 46-47, and 
 9-ethyl-fluorene (C 6 H 4 ) 2 CHC 2 H 5 , m.p. 108, b.p. ls 166 (B. 35, 759). 
 
 _co COOH 
 
 Diphenylene-ketone-carboxylic acids, or i-acid I I ~l i 
 
 The a-acid, melting at 191, is produced by the oxidation of fluoranthene 
 with a chromic acid mixture. Sodium amalgam converts it into 
 
 a-fluorenic acid C 6 H 4 .CH 2 .C 6 H 3 .CO 2 H, melting at 245, which yields 
 fluorene if it be distilled with zinc dust. Iso-diphenic acid results 
 
FLUORENE GROUP 701 
 
 when it is fused with potassium hydroxide, while heating with lime 
 breaks it down into carbon dioxide and diphenylene-ketone. 
 
 C0_ 
 The y-, ortho-, or 4-acid J p J ! is formed when diphenic 
 
 HOCO 
 
 acid is heated. It melts at 227. Fusion with caustic potash changes 
 it to diphenic acid (B. 20, 846 ; 22, R. 727). Also from diphenic 
 anhydride with A1C1 3 in benzene, besides o-benzoyl-fluorenone, m.p. 95 
 (C. 1902, I. 875). 
 
 HOCO CO 
 Diphenylene-ketone-1, 7-dicarboxylic acid Jj _ n _ ^j _ I COOH 
 
 is formed from retene-quinone (above) with MnO 4 K. It is a yellow 
 powder, decomposing at 270 into CO 2 and diphenylene-ketone-2-ear- 
 boxylic acid, m.p. 275. Distilled with lime it forms diphenyl. On 
 heating its silver salt it forms diphenylene-ketone, and, on further 
 oxidation with MnO 4 K, a mixture of I, 2, 3- and I, 2, 4-benzol-tricar- 
 boxylic acid (A. 229, 158 ; C. 1904, II. 449 ; 1910, I. 1530). 
 
 co_ 
 3-Oxy-diphenylene-ketone-2-carboxylie acid | I - _ j _ LCOOH, 
 
 OH 
 
 m.p. 278, is formed by nuclear synthesis in the action of concentrated 
 potash upon indane-dione-methenyl-aceto-acetic ester (C. 1906, 1. 849). 
 
 C 10 H 5 -COOH 
 Chryso-ketone-carboxylic acid I \ co , m.p. 283, is formed, 
 
 C 6 H 4 / 
 
 besides small quantities of an isomeric acid, by the action of 
 concentrated SO 4 H 2 upon chryso-diphenic acid (A. 335, 119). A 
 third isomeric allo-chryso-ketone-earboxylie acid, m.p. 288, has been 
 obtained by heating i-phenyl-naphthalene-2, 3-dicarboxylic acid with 
 concentrated H 2 SO 4 (C. 1908, II. 1360). 
 
 Fluor anthene and pyrene, occurring in the " stubb fat " of Idria, 
 are also found with the condensed hydrocarbons just mentioned in the 
 high boiling fractions of coal-tar. 
 
 Fluoranthene C 15 H 10 , idryl, melts at 110. Its picric acid compound 
 melts at 182. Fluoranthoquinone C 15 H 8 O 2 is obtained by oxidising 
 idryl with chromic acid. It melts at 188, and may be further oxidised 
 (with the elimination of CO 2 ) to obtain a-diphenylene-ketone-car- 
 boxylic acid. 
 
 The constitution of fluoranthene and of fluoranthoquinone probably 
 corresponds to the formulae (A. 200, i) : 
 
 C 8 H 4 - C 6 H 4V . 4X 
 
 >CH >CH X *\CO 
 
 C 6 H 3 <^ C H 3\ > co C.H 3 / 
 
 X CH=CH \co/ \CO,H 
 
 Fluoranthene Fluoranthoquinone ct-Diphenylene-ketone- 
 
 carboxylic acid. 
 
 Cp. also phthalacene C 20 H 16 (B. 17, 1389 ; C. 1908, I. 644 ; 1909, 
 I- 535). 
 
 V. ANTHRACENE GROUP. 
 
 Anthracene (from avdpa, carbon), occurring together with the iso- 
 meric phenanthrene in the high-boiling portions of coal-tar, is the 
 parent substance of a large group of bodies to which a series of vegetable 
 
702 ORGANIC CHEMISTRY 
 
 compounds, and in particular the very important dye (alizarin ,purpurin, 
 etc.) of madder root belong. 
 
 Synthetic Methods for the Production of Anthracene Derivatives. 
 
 1. Anthracene may be formed from benzene, acetylene tetra- 
 bromide, and A1C1 3 (B. 16, 623). 
 
 2. It is also produced from methylene bromide, benzene, and A1 2 C1 6 . 
 Dihydro-anthracene is the primary product, but it loses two atoms of 
 hydrogen, and anthracene results. 
 
 3. Further, dihydro-anthracene, and subsequently anthracene, is 
 obtained (together with toluene) from two molecules of benzyl chloride 
 on heating it with aluminium chloride or with water to 200 (Limpricht, 
 1866), when dibenzyl will also be produced. 
 
 Anthracene may also be derived from diphenyl-methane with 
 A1C1 3 . It is very probable that the diphenyl-methane is first resolved 
 into benzyl chloride and benzene. Unsym. diphenyl-ethane in an 
 analogous manner yields ms-dimethyl-anthracene (B. 27, 3238). 
 
 4. Finally, dihydro-anthracene is obtained from two molecules of 
 o-bromo-benzyl bromide by the action of metallic sodium (B. 12, 1965) 
 (cp. p. 689) : 
 
 BrCHBr /CH S 
 
 (1) C 6 H 6 + I +C 6 H 6 -'-> C 6 H 4 <J SC.H t 
 
 BrCHBr X CH/ 
 
 BrCH 2 Br _ HB] . y CH. 
 
 (2) C 6 H 6 + I +C 6 H 6 -- > C.H 4 < I >C 6 H 4 
 
 BrCH 2 Br X CH/ 
 
 C1CH 2 _ 9Hn / \ 
 
 (3) C 6 H 5X + \C 6 H 6 --> C 6 H/ | >C 6 H 4 
 
 \CH 2 C1 X CH/ 
 
 <CH 2 Br Br 
 
 Br + BrCH 
 
 Anthraquinones are obtained (5^) by the action of zinc dust upon 
 the chloride of phthalic acid and benzene. (56) Similarly, oxy-anthra- 
 quinones are produced on heating phthalic anhydride with one molecule 
 of a mono- or polyhydric phenol and sulphuric acid to 150. If there 
 is an excess of phenol present, phthaleins result. (6) o-Benzoyl- 
 benzoic acid and P 2 O 5 yield anthraquinone on the application of heat. 
 The substituted benzoyl-benzoic acids form the substituted anthra- 
 quinones, and benzyl-benzoic acid forms anthrone. (7) Di- and tetra- 
 oxy-anthraquinones are formed when metaoxy- and dimeta-dioxy- 
 benzoic acids are heated with sulphuric acid : 
 
 (ja) C 6 H, +C S H 6 
 
 ( 5 b) C.H 
 
 C 6 H 4 <>C 6 H 4 
 (7) OH.C,H 4 / + HOOC / C H ' H - ->OH.C 6 H 3 <^>C 6 H 3 .OH 
 
 The methods just given and a series of others e.g. the production of 
 anthraquinone from o-tolyl-phenyl-ketone and lead oxide, and that of 
 
ANTHRACENE GROUP 703 
 
 anthracene and methyl-anthracene from otolyl-phenyl-ketone and 
 o-ditolyl-ketone by means of zinc dust (B. 23, R. 198) demonstrate 
 the accepted symmetry of the derivatives of anthracene, which is 
 further proved by the following fact : brominated o-benzoyl-benzoic 
 acid from o-phthalic acid yields bromo-anthroquinone ; the oxy-anthra- 
 quinone obtained from the latter, however, can be oxidised to o-phthalic 
 acid ; so that both in the synthesis and decomposition of the molecule 
 o-phthalic acid appears, which, in the first instance, is connected with 
 the one and in the second case with the second half of the molecule 
 (cp. constitution of naphthalene) (B. 12, 2124) : 
 
 r[i]CO.c 6 H 5 _ V OHCH / [I]CO[I] VH _ > HOOC[I] 
 
 Br.C 6 H 3 ^ [2]COQH -C 6 H 3 ^ [2]CO[2] j>C 6 H 4 - -> HOOCj>] 
 
 Therefore anthraquinone and anthracene, which are genetically con- 
 nected, have a symmetrical constitution corresponding to the symbols : 
 
 CH CO 
 
 Anthracene Anthraquinone. 
 
 Anthracene is a nucleus resulting from the condensation of three 
 benzene nuclei, of which the intermediate or middle member shows a 
 para-union. The positions i, 4, 5, 8 (a-) are alike ; also 2, 3, 6, 7 (j3-). 
 By the replacement of the middle hydrogen atoms of anthracene 
 y-derivatives or w^so-derivatives are obtained. In contrast with this 
 the substituents of the two outer benzene nuclei are designated by the 
 prefix benz. In most of the anthracene transpositions the intermediate 
 C atoms are first attacked. 
 
 Anthracene C 14 H 10 , melting at 213 and boiling at 351, is isomeric 
 with phenanthrene, and is produced according to the methods indicated 
 above. (See also B. 28, R. 148.) It is found in large quantities in 
 coal-tar. 
 
 Crude anthracene, boiling at 34O-36o and beyond, is best purified 
 by treating it with liquid sulphurous acid, which chiefly takes up the 
 admixtures (B. 26, R. 634). For additional methods of purification, see 
 B. 18, 3034 ; 21, R. 75 ; A. 191, 288. Chemically pure anthracene is 
 prepared by heating anthraquinone with zinc dust. 
 
 Anthracene crystallises in colourless monoclinic tables, showing a 
 beautiful blue fluorescence. It dissolves with difficulty in alcohol and 
 ether, but easily in hot benzene. Picric acid unites with it, yielding 
 C 14 H 10 .C 6 H 2 (NO 2 ) 3 OH, crystallising in red needles, and melting at 138. 
 
 When the cold saturated solution of anthracene in benzene, or, 
 better, in xylene (B. 26, R. 547), is exposed to sunlight, a dimolecular 
 modification of anthracene, para-anthracene (C 14 Hi ) 2 , separates out 
 in plates. It dissolves with difficulty in benzene, is not attacked by 
 nitric acid or bromine, melts at 244, and, in so doing, reverts to 
 common anthracene. 
 
 /CH V /CR V 
 
 Alkylic Anthracenes. (a) c,H 4 </| ^>C 6 H 3 R; (b) c 6 H 4 <(j p>c 6 H 4 
 
 Benzalkyl derivatives meso- or y-Alkyl 
 
 derivatives. 
 
704 ORGANIC CHEMISTRY 
 
 (a) The benzo-mono-alkylic anthracenes can exist in two isomerides 
 (a- and )S-). 
 
 a-Methyl-anthracene C 6 H 4 (CH 2 )C 6 H 3 [i]CH 3 , m.p. 86, is formed by 
 zinc dust distillation from I, 4-chloro-methyl-anthraquinone (/. pr. Ch. 
 2, 83, 201). 
 
 ^-Methyl-anthracene C 6 H 4 (CH 2 )C 6 H 3 [2]CH 3 , m.p. 207, closely 
 resembles anthracene, and is found in the crude anthracene of coal-tar. 
 
 At high temperatures it is formed out of ditolyl-methane and ethane 
 (/. pr. Ch. 2, 79, 555) ; also by boiling benzoyl-xylol C 6 H 5 CO.C 6 H 3 
 (CH 3 ) 2 ; by reduction of j8-methyl-anthraquinone with zinc dust 
 (A. 311, 181) ; and from vegetable chrysophanic acid and emodin, 
 which are hydroxylated methyl-anthraquinones. By oxidation with 
 nitric acid, methyl-anthracene forms methyl-anthraquinone, and with 
 chromic acid mixture and oxidation of the methyl group it forms 
 anthraquinone-carboxylic acid. In sunlight it polymerises like 
 anthracene to dimethyl-dianthracene, m.p. 229 (C. 1899, II. 623). 
 
 1, 6- and 2, 6-Dimethyl-anthraeene C 14 H 8 (CH 3 ) 2 , m.p. 240 and 244, 
 are formed together from toluol and methylene chloride or acetylene 
 tetrabromide with A1C1 3 (method 2). The second body has also been 
 obtained by boiling m-xylyl-tolyl-ketone (C. 1910, II. 1386 ; 1911, I. 
 1294). From the aniline oils of high boiling-point also a dimethyl- 
 anthracene has been obtained. 
 
 (b) Meso- or y-alkyl- anthracenes are obtained from the alkylic 
 
 /T^T? /f > kTT\\ 
 
 hydranthranols C 6 H 4\ CH /C 6 H 4 by the elimination of water. 
 
 This happens on boiling them with alcohol, hydrochloric acid, or picric 
 acid (A. 212, 100). Alkylic oxanthranols are formed upon oxidation : 
 y-ethyl-, iso-butyl-, and amyl-anthracenes, melting at 60, 57, and 59. 
 y-Phenyl-anthraeene C 14 H 9 (C 6 H 5 ), melting at 152, is obtained from 
 phenyl-anthrone. 
 
 y- or 9, 10-Diphenyl-anthraeene C 6 H 4 (C.C 6 H 5 ) 2 C 6 H 4 , m.p. 240, 
 from diphenyl-dioxy-anthracene hydride with zinc dust and glacial 
 acetic acid (C. 1904, II. 117 ; 1906, I. 44). 
 
 y- or 9, 10-Diriiethyl-anthraceneC 6 H 4 (C.CH 3 ) 2 C 6 H 4 , melting at 179, 
 is derived from its dihydride, the condensation product obtained from 
 ethidene chloride and benzene by means of A1 2 C1 6 (see' B. 21, 1176). 
 
 9, 10-Dibenzyl-anthracene C 6 H 4 (C.CH 2 C 6 H 5 ) 2 C 6 H 4 , m.p. 240, is 
 formed by prolonged boiling of anthracene with benzyl chloride and a 
 little zinc dust in CS 2 solution (C. 1902, II. 745 ; 1904, II. 1136). 
 
 Substituted Anthracenes. Chlorine and bromine acting upon the 
 CS 2 solution of anthracene first substitute the middle CH groups with 
 the production of y-mono- and dihalogen-anthraeenes. y-Dibromo- 
 anthracene is also formed by the action of bromine upon anthracene 
 hydride. 
 
 The action of nitric acid upon anthracene easily produces anthra- 
 quinone and nitrified anthraquinones. But on nitrifying with acetic 
 anhydride and sulphuric acid in glacial acetic acid at i5-2O, we obtain 
 9-nitro-anthracene C 14 H 9 .NO 2 , yellow needles, m.p. i45-i46, which 
 may be distilled under reduced pressure, and 9, 10-dinitro-anthracene 
 C 10 H 8 (NO 2 ) 2 , m.p. 294. These compounds are easily obtained in- 
 directly. On digesting anthracene in glacial acetic acid with one 
 molecule nitric acid at 30-35, we obtain the acetate of nitro-hydran- 
 
ANTHRACENE GROUP 705 
 
 thranol cc< r t f which, with HC1, yields the corre- 
 
 \C 8 H 4 / 
 
 spending chloride, with N 2 O 3 the nitrite, and with alcohol the ethers, 
 also produced direct on nitrifying with HNO 3 and the alcohols. On 
 treatment with alkali, the chloride forms g-nitro-anthracene, and 
 this, treated with NO 2 in chloroform, gives trinitro-hydranthranol 
 
 (NO 2 ) 2 C<f^ 6 ^ 4 \CH(NO 2 ), which, with alkali, yields 9, lo-dinitro-anthra- 
 
 \C 6 H 4 / 
 
 cene. In a similar manner, 9-ethyl-10-nitro-anthraeene C 14 H 1S (C 2 H 5 ) 
 (NO 2 ), m.p. 135, has been obtained from ethyl-anthracene. By boiling 
 with alcoholic potash, g-nitro-anthracene has been transposed, by way 
 of several intermediaries due to the addition of potassium alcoholate, 
 
 etc., into anthraquinone - oxime CH^ffi^c.NO^co^ffiNc : NOH 
 
 \C 6 hL 4 / \C,i 4 / 
 
 (cp. g-nitro-phenanthrene). When nitric acid acts upon anthracene 
 in iso-butyl alcohol, we obtain nitro-anthrone CO(C 6 H4) 2 CH.NO 2 , 
 which is converted by alkali into a red isomer CO(C 6 H 4 ) 2 C : NOOH (?) 
 (A. 330, 133 ; B. 42, 1216). 
 
 9- or meso-Amido-anthraeene, anthramine, m.p. i45-i5o, from 
 g-nitro-anthracene with SnCl 2 and HC1 ; dinitro-anthracene cannot 
 be reduced to diamido-anthracene. The 9-anthramine, like the a- or 
 1 -anthramine, m.p. 130, and the jS- or 2-anthramine, m.p. 237, has 
 also been obtained from the corresponding oxy-anthracenes by heating 
 with NH 3 . With diazo-benzol chloride, the 9-amido-anthracene unites 
 to form benzol-azo-meso-anthramine C 6 H 5 N : N.C 14 H 8 .NH 2 , m.p. 183, 
 which is split up by acids into anthraquinone, phenyl-hydrazin, and 
 ammonia (B. 40, 518), and passes on reduction into the easily oxidised 
 1, 4-anthra-diamine (B. 41, 1434) ; meso-phenyl-anthramine, m.p. 
 203 (C. 1909, II. 1249). 
 
 Anthracene - sulphonic acids are formed from anthracene with 
 sulphuric acid, and by reduction of anthraquinone-sulphonic acids. 
 1-Anthracene-sulphonie acid, see B. 37, 70. On moderate treatment 
 with dilute sulphuric acid, anthracene yields 2-anthracene-monosul- 
 phonic acid C 14 H 9 .SO 3 H, chloride, m.p. 122 (B. 28, 2258). Concen- 
 trated H 2 SO 4 produces i, 5- and i, 8-anthracene-disulphonic acids 
 (chlorides, m.p. 249 and 225), which, on fusion with potash, form the 
 corresponding dioxy-anthracenes mfol and chrysazol (B. 42, 1413). 
 
 /CH X /COH X 
 
 Oxy-anthracenes: (i) C 6 H 4 /| V 6 H 3 OH. (2) C 6 H/| )>C 6 H 4 . 
 
 x3H CH ' 
 
 (i) a- and jS-Monoxy-anthracene, a- and j3-anthrol, behave like 
 phenols or naphthols. a-Anthrol, from i-anthracene-monosulphonic 
 acid by fusion with potash, forms yellowish flakes, melting at 152 
 (B. 37, 71). /?-Anthrol, from jS-anthracene-sulphonic acid and j8-oxy- 
 anthraquinone, is changed by nitrous acid to a-nitroso-/2-anthrol 
 C 6 H 4 (CH) 2 C 6 H 2 (OH)(NO), which, upon reduction, yields a-amido-jS- 
 anthrol. The latter may be oxidised to 1, 4 - anthraquinone 
 
 CH C CO CH 
 C 6 H 4 <( J melting with decomposition at 208, and isomeric 
 
 \CH C CH CH 
 
 with a-naphtho-quinone (B. 39, 926 ; 41, 1434 ; A. 344, 78). i, 2- 
 Anthraquinone, similarly formed from the a-anthrol, gives on reduc- 
 VOL. II. 2 z 
 
706 ORGANIC CHEMISTRY 
 
 tion with zinc dust and glacial acetic acid 1, 2-anthra-hydroquinone 
 C 6 H 4 (CH) 2 C 6 H 2 (OH) 2 , m.p. 131 with decomposition (A. 342, 59). 
 The anthrols can only be oxidised by CrO 3 to oxy-anthraquinones 
 after acetylating the OH group (cp. oxidation of phenols). The i, 2- 
 anthra-hydroquinones in this manner yields alizarin. 
 
 Benzo-dioxy-anthraeenes. Two isomerides ehrysazol and rufol, 
 m.p. 225 and 265 having the formula OH.C 6 H 3 : (CH) 2 : C 6 H 3 OH, 
 are obtained from a- and j8-anthracene-disulphonic acids. When their 
 acetyl derivatives are oxidised and saponified, chrysazine and anthra- 
 rufin result. These are the corresponding dioxy-anthraquinones. 
 
 2, 3-Dioxy-anthracene, decomposing at 180 by reduction of 
 hystazarin-dimethyl ether with zinc dust and NH 3 , and saponification 
 with HI (A. 342, 90). 
 
 (2) meso - Oxy - anthracene, anthranol C 6 H 4 <^ H ^>C 6 H 4 , yellowish- 
 brown needles, m.p. 120 when quickly heated, desmotropic with 
 anthrone C 6 H 4 <^ ^>C 6 H 4 , colourless brilliant needles, m.p. 155 (A. 
 
 379, 37). The latter is formed synthetically from b-benzyl-benzoic 
 
 /CH r TT 
 acid C 6 H 4\QOOH with concentratecl sulphuric acid at 90 (B. 27, 
 
 2789), also from phthalide chloride, benzene, and A1C1 3 , and is 
 obtained by reduction of anthraquinone with tin or zinc and glacial 
 acetic acid besides dianthryl (C 14 H 9 ) 2 (A. 379, 55 ; C. 1908, II. 1218). 
 Anthranol acetate, m.p. 134, is also formed by the oxidation of 
 anthracene and PbO 2 in glacial acetic acid (A. 379, 75). The anthrone 
 is insoluble in cold alkali, but dissolves on heating with formation of 
 salts of anthranol, which can be precipitated from this solution by a 
 careful addition of dilute H 2 SO 4 . The isomers capable of independent 
 existence in the solid state, form, on solution or melting, an allelotropic 
 mixture of both forms, in which the more stable anthrone is predomi- 
 nant. The solutions therefore show reactions characteristic of both 
 forms : on heating with acetic anhydride we obtain anthranol acetate, 
 but on alkylating with C 2 H 5 I and potash we obtain, simultaneously, 
 
 anthranol - ethyl ether cH^^5i\coc 2 H 5 , liquid, ethyl - anthranol- 
 
 /rir\ 
 ethyl ether c 2 H 5 c x r*" 4 )coc 2 H 5 , m.p. 77, and diethyl - anthrone 
 
 /r w \ \ U * M 4/ 
 
 (C 2 H 5 ) 2 C<^ 6 4 >CO, m.p. 136 (B. 21, 2505). With benzaldehyde, 
 
 \L/(j.rI 4 / 
 
 anthrone condenses, under the influence of piperidin, to benzylidene- 
 anthrone C 6 H 5 CH : C(C 6 H 4 ) 2 CO, yellow needles, m.p. 127 (C. 1906, I. 
 138) ; with benzo - phenone chloride to diphenyl - anthraquinone- 
 methane (C 6 H 5 ) 2 C : C(C 6 H 4 ) 2 CO, m.p. 196 (C. 1910, I. 1722). With 
 benzol - diazonium chloride it forms benzol - azo - anthranol 
 
 C 6 H 5 N : NC^54^>COH, m.p. 183, identical with the anthraquinone- 
 
 \C 6 ri 4 / 
 
 monophenyl-hydrazone formed from dibromanthrone CBr 2 (C 6 H 4 ) 2 CO, 
 m.p. 157, and phenyl-hydrazin (B. 40, 518). By the action of atmo- 
 spheric oxygen, or mild oxidisers like FeCl 3 , HgO, etc., anthrone and 
 anthranol are oxidised to meso - dihydro - dianthrone CO(C 6 H 4 ) 2 CH. 
 CH(C 6 H 4 ) 2 CO, m.p. 245, which is also obtained from mono-brom- 
 anthrone, m.p. 148, by heating with copper powder. It is insoluble 
 in alkalies, but, on heating with alcoholic alkali, it forms the alkali 
 
ANTHRACENE GROUP 707 
 
 salt of dianthranol HOCcoH, yeUowish crystals, m.p. 
 
 \^6-"-4/ \**4/ 
 
 230, easily obtained by reduction of anthraquinone, with zinc dust and 
 soda under pressure at 160, and transposed by alcoholic HC1 into meso- 
 dihydro-dianthrone. By oxidation with FeQ 3 it passes into the 
 dianthrone CO(C 6 H 4 ) 2 C : C(C 6 H4) 2 CO, analogous to dipheno-quinone, 
 in the shape of a lemon-yellow powder from which zinc dust and glacial 
 acetic acid regenerate dianthranol (M. 30, 165). 
 
 /S-Methyl-anthrone, m.p. 87 (C. 1910, I. 1722). Oxy-anthrone 
 
 C 6 H 4 ^ 'Nc 6 H 3 (OH), m.p. 221, is prepared from oxy - dimethyl- 
 
 methane-o-carboxylic acid (B. 31, 2793). Dimethyl-amido-anthrone 
 C 14 H 10 O[N(CH 3 )2], m.p. 8o-85, is obtained from o-dimethyl-amido- 
 benzyl-benzoic acid, with H 2 SO 4 (A. 307, 313). 
 
 /C(OH) X 
 Dioxy-anthrone C 6 H 4 / | ^>C 6 H 2 (OH) 2 , so-called anthrarobin, results 
 
 when alizarin is reduced with zinc dust and ammonia. It has been 
 applied therapeutically in certain skin diseases. 
 
 A few isomeric dioxy-anthranols have been obtained by reduction 
 of quinizarin, anthra-rufin-hystazarin, and chrysazin with HI (B. 35, 
 2923, 2930 ; 36, 2938). 
 
 meso-Phenyl-anthrone C 6 H 5 CH(C 6 H 4 ) 2 CO, m.p. I4i-i44, is formed 
 when sulphuric acid acts upon triphenyl-methane-o-carboxylic acid. 
 Its oxidation product is phenyl-oxanthrone. It yields phenyl-anthra- 
 cene by reduction. Substituted triphenyl-methane-carboxylic acids 
 form substituted phenyl-anthrones. In accordance with their source, 
 the hydroxyl - phenyl - anthrones, like dioxy - phenyl -anthrone, 
 
 c 6 H 3 OH, have been designated phthalidins because 
 
 they are formed from the phthalins, the reduction products of the 
 phthaleins or diphenol-phthalides. When oxidised, the phthalidins 
 become phthalide'ins, hydroxyl-phenyl-oxanthranols. 
 
 Diphenyl-anthrone CeH^^^a^H,, m .p. 192, is a derivative 
 
 of anthrone. It is obtained by condensing unsym. phthalylene 
 tetrachloride with benzene, as well as from phenyl-oxanthrone by 
 means of benzene and sulphuric acid (B. 28, R. 772). 
 
 On reduction with zinc dust and glacial acetic acid it yields 9, 9- 
 diphenyl-dihydro-anthraeene. Mixed diaryl-anthrones are obtained, 
 either from phenyl-oxanthrone, benzene homologues, and H 2 SO 4 , or, 
 with benzene derivatives and A1C1 3 , from phenyl-oxanthranyl chloride 
 co< /c (1 H 4 \ >c< /CeH 5 ^ mp ^o. the latter is f orme( i f rom diphenyl- 
 
 phthalide on heating with PC1 5 to 140 (C. 1898, I. 209 ; 1899, II. 
 204). With phenols it condenses on simply heating the components 
 to form oxy-diphenyl-anthrones (B. 38, 3802). meso-Dichloranthrone 
 CO(C 6 H 4 ) 2 CC1 2 , m.p. 133, from o-tolyl-phenyl-ketone by heating 
 with chlorine to 120, or by heating anthrone with Cl, gives, with 
 dimethyl-aniline and A1C1 3 , tetramethyl - diamido - diphenyl - anthrone 
 [(CH 3 ) 2 NC 6 H 4 ] 2 C(C 6 H 4 ) 2 CO, yellow needles, m.p. 278 (C. 1903; 
 I- 837). 
 
 From anthrone, also, the group of anthro-cumarins can be derived, 
 These are produced by condensing cinnamic acids and oxy-benzoic 
 
7 o8 ORGANIC CHEMISTRY 
 
 acids by means of sulphuric acid. Anthra-eumarin ^ 4 
 
 m.p. 260, from m-oxy-benzoic acid and cinnamic acid ; dioxy-anthra- 
 cumarin, styro-gallol, from gallic and cinnamic acids (B. 20, 2588, 3143 ; 
 
 C. 1899, II. 967). Cp. also the benzoin yellow ^^^^^^ (?) 
 produced from benzoin and gallic acid (B. 31, 2975). 
 
 meso - Dioxy - anthracene, anthra - hydroquinone C 6 H 4\/ O] [\^ C H 4' 
 brown needles, with a diaceto-compound melting at 260, desmotropic 
 with oxanthrone C 6 H 4 <^^ \c 6 H 4 , white needles with a yellow 
 
 tinge, m.p. 167, are related to each other like anthranol and anthrone, 
 except that mutual transformation in solutions is exceedingly slow, 
 and that the enol-form, anthra-hydroquinone, is the more stable. 
 Anthra-hydroquinone is formed by reducing anthraquinone with 
 zinc dust and potash ; it oxidises back to anthraquinone in the air. 
 In alkalies it easily dissolves with a red colour. Treatment with 
 alcoholic HC1 converts it, to a slight extent, into oxanthrone, which is 
 easily obtained by heating bromanthrone with aqueous acetone, or 
 direct, by the action of bromine upon anthracene in aqueous acetone 
 solution. Reduction with zinc dust and glacial acetic acid produces 
 anthranol and anthrone respectively. Heating with alkali or alcoholic 
 HC1 converts oxanthrone into anthro-hydroquinone. On alkylating 
 anthra-hydroquinone with alkyl iodide or dialkyl sulphate and alkali, 
 the mono- and dialkyl ether of anthra-hydroquinone and alkyl- 
 
 oxanthrone are obtained together C fl H 4 / c(o ^? Alk \c 6 H 4 (A. 379, 43). 
 
 Anthracene -carboxylic Acids. The a- and j8-acids C 6 H 4 (CH) 2 
 C 6 H 3 COOH are formed from the anthracene-monosulphonic acids by 
 means of the cyanides, and from the anthraquinone-carboxylic acids 
 by reduction with ammonia and zinc dust ; the a-acid melts at 245, 
 the j8-acid at 281. 
 
 meso-Anthracene-carboxylic acid is formed from its chloride, which 
 is produced when anthracene is heated with phosgene or, better, oxalyl 
 chloride, to 160 (B. 44, 205). It melts at 217 with decomposition. 
 Chromic acid oxidises it to anthraquinone. 
 
 meso-Benzoyl-anthracene, anthra-phenone C 14 H 9 .COC 6 H 5 , m.p. 148, 
 is obtained from anthracene, benzoyl chloride, and zinc dust or A1C1 3 . 
 In the latter case two isomers, melting at 75 and 203 respectively, are 
 also obtained (B. 33, 816 ; 34, 2766). 
 
 Hydro-anthracenes. Anthracene dihydride C 14 H 12 results from the 
 action of sodium amalgam upon the alcoholic solution of anthracene. 
 It can also be obtained by many other synthetic methods. On heating 
 with hydriodic acid or with hydrogen and nickel at 200-25o, we 
 obtain tetra-, -hexa-, -octo-, and -perhydride C 14 H 14 , C 14 H 16 , C 14 H 18 , 
 and C 14 H 24 , m.p. 89, 63, 7*> and 88, b.p. 310, 290, 293, and 270 
 (B. 21, 2510 ; 41, 996 ; A. Chim. Phys. 8, 12, 468). 
 
 meso-Alkylic derivatives of anthracene dihydride are produced in the 
 reduction of the alkyl-oxanthrones, and meso-dialkyl derivatives syn- 
 thetically from alkylidene chlorides, benzene, and A1C1 3 . 
 
 meso-Dimethyl-anthracene hydride C 6 H 4 (CH.CH 3 ) 2 C 6 H 4 , m.p. 181, 
 yields anthraquinone by oxidation (A. 235, 305), just as benzo-phenone 
 
ANTHRACENE GROUP 709 
 
 is obtained from unsym. diphenyl-ethane. It is obtained from ethy- 
 lidene chloride, benzene, and A1C1 3 . meso-Diphenyl-anthracene hydride, 
 m.p. 153, from benzal chloride, benzene, and A1C1 3 , besides triphenyl- 
 methane (Am. Ch. J. 13, 556). 
 
 9, 9-Diphenyl-dihydro-anthracene (C 6 H 5 ) 2 C(C 6 H 4 ) 2 CH 2 , m.p. 196, 
 by reduction of diphenyl-anthrone with zinc dust in glacial acetic acid 
 (B. 38, 1800). 
 
 Anthraquinone or diketo-dihydro-anthracene must be included with 
 the derivatives of dihydro-anthracene. Thereto belong also : 
 
 Anthrone and oxanthrone, which have already been discussed in 
 connection with anthranol and dioxy-anthraquinone. We must also 
 
 include dihydro- anthranol C 6 H 4 <^^>C 6 H 4 , m .p. 76, obtained 
 
 by reducing anthraquinone with zinc dust and ammonia. It easily 
 decomposes into water and anthracene on standing in air. The 
 
 alkyl derivatives of dihydro-anthranol C,H 4 /^ ^/C 6 H 4 are 
 
 obtained by reduction of the alkyl-oxanth rones, or, direct, by the 
 reduction of anthraquinone with zinc dust and soda in the presence of 
 halogen-alkyls. Like dihydro-anthranol, they easily split off water on 
 boiling with HC1 and pass into y-alkyl-anthracenes (B. 18, 2150 ; 24, 
 R. 768 ; A. 212, 67). 
 
 meso - Triphenyl - hydranthranol (C 6 H 5 ) 2 C(C 6 H 4 ) 2C(OH)C 6 H 5 , m.p. 
 200, from diphenyl-anthrone with C 6 H 5 MgBr, gives on reduction 
 triphenyl - hydranthracene (C 6 H 5 ) 2 C(C 6 H 4 ) 2 CHC 6 H 5 , m.p. 220. The 
 latter also results from the condensation product of triphenyl-methane- 
 carboxylic ester with C 6 H 5 MgBr by treatment with H 2 SO 4 (C. 1904, 
 
 II. 530). 
 
 Phenyl-oxanthrone is formed by the oxidation of phenyl-anthrone, 
 and the action of C 6 H 5 MgBr upon anthraquinone. In a similar manner, 
 several further meso-aryl- and meso-alkyl-anthracenes have been 
 converted into the corresponding oxanthranones. Thus we get the tetra- 
 
 methyl - diamido - phenyl - oxanthrone y^^C^^te^CO, 
 
 m.p. 213, from the condensation product of tetramethyl-diamido- 
 diphenyl-methane-o-carboxylic acid. It combines with dimethyl-aniline 
 and POC1 3 to form the dyestuff Phal green, the chloride of the base 
 
 c = H <c!oH![c:H;N|cH:i:]> c H 3 N ( cH 3) 2 <c. 1903, n. nso), which 
 
 based upon diphenyl - dioxy-anthracene hydride C 6 H 4 [C(OH)C 6 H 5 ] 2 
 C 6 H 4 , m.p. 242. The latter, from anthraquinone with phenyl-mag- 
 nesium bromide, condenses easily, like meso-triphenyl-hydranthranol, 
 with phenols and aromatic amines to tetra-aryl-dihydro-anthracenes 
 (C. 1904, I. 814 ; 1905, I. 744). 
 
 Dimethyl- and diethyl-dioxy-anthracene hydride C 6 H 4 [CR(OH)] 2 
 C 6 H 4 , m.p. 181 and 175, from anthraquinone, with methyl- and ethyl- 
 magnesium iodide respectively (C. 1906, I. 47). 
 
 Anthraquinone, diphenylene-diketone C 6 H 4 (CO) 2 C 6 H 4 , melting at 
 285 and boiling at 382, sublimes in yellow needles. It is not only 
 produced by synthetic methods, but also quite easily by the oxidation 
 of anthracene with a chromic acid mixture (technical preparation, A. 
 Suppl. 7, 285), as well as from anthra-hydride, meso-dichloro-, dibromo-, 
 and dinitro-anthracene. It is, compared with the isomeric'phenanthra- 
 
710 ORGANIC CHEMISTRY 
 
 quinone, very stable toward oxidants. It combines with hydroxyl- 
 amine to anthraquinone-oxime, subliming above 200. Sulphurous 
 acid does not reduce it (unlike the true quinones). 
 
 It reverts to anthracene if heated to 150 with hydriodic acid, or 
 with zinc dust and ammonia. A variety of intermediate products are 
 obtained in this reaction by simply applying different reducing agents : 
 
 .H. _ C.H<C,OH, >C>H . 
 Anthraquinone Anthra-hydroquinone 
 ~ H * CH 
 
 or C H 
 OT C H 
 
 Anthranol Anthrone Dihydro-anthranol Anthracene. 
 
 On digesting with zinc dust and soda, anthra-hydroquinone is formed, 
 and its red alkaline solution, shaken in air, regenerates anthraquinone 
 (qualitative test for anthraquinone). 
 
 When fused with potassium hydroxide (at 250), it decomposes into 
 two molecules of benzoic acid ; heated with soda-lime, it yields benzene 
 and a little diphenyl. 
 
 Homologous anthraquinones are obtained partly in the synthetic way 
 and in part by the oxidation of benz-alkylic anthracenes. 
 
 Methyl-anthraquinone C 6 H 4 (CO) 2 C 6 H 3 .CH 3 , melting at 177, from 
 nitric acid and methyl-anthracene, is also present in crude anthra- 
 quinone. 
 
 Substituted Anthraquinones. Halogen-anthraquinones are formed 
 (i) by the action of chlorine or bromine upon anthraquinone ; (2) from 
 chlorine- and bromine-anthracenes by oxidation ; (3) from amido- 
 anthraquinones by means of their diazonium salts (B. 37, 59) ; (4) by 
 the action of chlorine and bromine upon anthraquinone or anthracene- 
 sulphonic acids in aqueous solution, the sulpho-groups being easily 
 replaced by halogen (C. 1909, I. 414 ; 1911, I. 102) ; (5) by synthesis 
 from halogen-benzo-phenone-o-carboxylic acids : 1-chloro-, bromo-, and 
 iodo-anthraquinone, m.p. 209, 205, and 176 ; from 2-bromo-anthra- 
 quinone and from dibromo-anthraquinone, alizarin is obtained by 
 fusing with potash. The halogen atoms in the a-position can easily 
 be replaced by the groups OH, OR, OC 6 H 5 , NH 2 , and NHR on heating 
 with lime-water, sodium alcoholate or phenolate, ammonia or amines, 
 if necessary with an addition of copper salts. 
 
 Nitro- anthraquinones. From anthracene or anthraquinone, by 
 heating with nitric acid, we obtain besides 1-nitro-anthraquinone, 
 m.p. 230, chiefly 1, 5-dinitro-anthraquinone (C. 1906, I. 1070). 2- 
 Nitro-anthraquinone, m.p. 185, has been obtained from 2-amido- 
 anthraquinone by transposition of the diazonium salt with sodium- 
 copper nitrite ; also from 3-amido-2-nitro-anthraquinone, by elimin- 
 ating the amido-group ; and synthetically from o-benzoyl-p-nitro- 
 benzoic acid (B. 37, 4435 ; 38, 295). By moderate alkaline reduction 
 of the nitro-anthraquinones we obtain comparatively stable /?- 
 hydroxyl-amino-anthraquinones C 14 H 7 O 2 (NHOH), C 14 H 6 O 2 (NHOH) 2 , 
 which, by transposition with acids, yield amino-oxy-anthraquinones 
 (B. 35, 666). 
 
 Amido-anthraquinones and their derivatives have lately acquired 
 great technical importance, since some of them, like the benzoyl-amido- 
 anthraquinones and tri-anthraquinone-di-imides, have the character 
 
ANTHRACENE GROUP 711 
 
 of vat dyes, and some of them, like 2-amido-anthraquinone, can be 
 easily converted into these by simple operations. Vat dyes are dyes 
 insoluble in water and alkalies, which can be converted by alkaline 
 reduction into hydro-compounds soluble in alkali, and then have the 
 faculty of combining with the fibre, and of regenerating the original 
 dye on the fibre by subsequent oxidation in air. All vat dyes contain 
 one or more CO groups, and their character depends upon the possibility 
 of converting these groups into OH groups capable of forming salts. 
 The vat dyes are mostly distinguished by their great permanence 
 (B. 43, 987 ; Ch. Ztg. 34, 731). 
 
 Amino-anthraquinones are formed (i) by the reduction of nitro- 
 anthraquinones ; (2) synthetically from amino-benzoyl-o-benzoic 
 acid by condensation (C. 1909, 1. 475) ; (3) by replacing nitro-, halogen-, 
 sulpho-, and hydroxyl-groups in the a- or i-position in anthraquinone 
 by NH 2 or NHR groups, on heating with ammonia, amines, and 
 particularly anilines, with the possible addition of copper powder 
 (C. 1901, II. 1379 > I 9 02 ' II- 368, etc.). 1- and 2-Amino-anthra- 
 quinone, red needles, m.p. 242 and 302. The 2-amino-anthra- 
 quinone is converted, by fusion with potash at 250, into the interesting 
 and valuable vat dye indanthrene (q.v.), and under different conditions, 
 such as heating with aluminium chloride or, better, by boiling with 
 antimony pentachloride in nitro-benzene solution, into the similar but 
 yellow-coloured flavanthrene (q.v.) : 
 
 Flavanthrene. 
 
 Di- and poly-amido-anthraquinones have been obtained by the 
 reduction of poly-nitro- or nitro-amido-anthraquinones, usually with 
 sodium sulphide : 1, 4-, 1, 5-, and 1, 8-diamido-anthraquinones melt 
 at 268, 319, and 262 (C. 1902, II. 1232 ; B. 38, 637). I, 2- and 2, 3- 
 Diamido-anthraquinones condense like o-phenylene - diamines with 
 o-diketones to azins (B. 37, 4531 ; C. 1906, II. 80). 
 
 As already mentioned, numerous acyl-derivatives of amido-anthra- 
 quinones, especially benzoyl - amido - anthraquinones, are directly 
 useful as vat dyes. The latter are either obtained from amido-anthra- 
 quinones with benzoyl chloride or from halogen-anthraquinones with 
 benzamide and copper powder. Benzoyl-a-amido-anthraquinone and 
 dibenzoyl-i, 5- and I, 8-diamido-anthraquinone give yellow colora- 
 tions, which are slightly displaced towards red by the substitution. 
 The amido-anthraquinone derivatives of dicarboxylic acid, malonic 
 acid, succinic acid, phthalic acid, etc., possess to some extent the 
 character of vat dyes. To these belong the dyes known as algol- 
 yellow W.G., algol-pink R, and algol-scarlet G. 
 
712 ORGANIC CHEMISTRY 
 
 Dianthra-quinonimides, dianthrimides 
 
 and trianthraquinone-di-imides, trianthrimides A NH A NH A 
 
 are formed by the condensation of mono- and diamido-anthra- 
 quinones with halogen-anthraquinones by boiling the components 
 with sodium acetate in nitro-benzol with perhaps some copper 
 powder (C. 1905, II. 1206). They possess an immediate dyestuff 
 character, though some of them require further transformations to 
 produce vat dyes. Some of their names are : indanthrene-claret B, 
 indanthrene-red G, algol-orange R, algol-claret 3B, and algol-red B. 
 
 Like o-amido-benzaldehyde and o-amido-acetophenone, a-amido- 
 anthraquinone is capable of forming heterocyclic ring-systems, the 
 linkage being in the I, g-position with respect to the anthraquinone 
 nucleus. Thus, by condensation with acetone and soda, analogous to 
 the formation of quinaldin from o-amido-benzaldehyde, we obtain a 
 
 c-methyl-anthra-pyridin a^^'ft** ( C - I 97' IL 86 3)' With 
 methane, a-amido-anthraquinone combines to form anthra-pyrimidone 
 
 CO C H IsTH (^" I 99' I- 3 2 7)> with formamide to anthra-pyrimidin 
 
 /~> TT p TSJ PfT 
 
 Co_lc * H '-^ (C. 1910, I. 1305). Other hetero-ring formations, see 
 C. i902, 3 II. 368 ; 1906, II. 386 ; 1908, II. 1658. 
 
 The action of NO 3 H upon the free amido-anthraquinones leads to 
 the very stable nitro-nitramino-anthraquinones (B. 37, 4227). The 
 simplest 1-nitramino-anthraquinone C 14 H 7 O 2 .NHNO 2 , yellow needles, 
 m.p. 193 with decomposition, is formed by the oxidation of i-anthra- 
 quinone-diazonium sulphate with sodium hypochlorite (C. 1905, 1. 313). 
 Somewhat easier is the nitrification of the acetyl compounds and the 
 urethanes of the amido-anthraquinones, the former yielding chiefly 
 p-nitro-, and the latter o-nitro- and o, p-dinitro-amido-anthraquinones 
 (C. 1906, II. 468). 
 
 On bromination i-amido-anthraquinone gives 2-bromo- and 
 2, 4-dibromo-anthraquinone, m.p. 181 and 222, whereas 2-amido- 
 anthraquinone gives the 1, 3-dibromo-2-amido-anthraquinone (B. 40, 
 1701 ; C. 1905, I. 1447). The 2-bromo-compound is of especial 
 interest, since, by heating with sodium acetate in nitro-benzol solution 
 and addition of copper chloride, it can be transformed into indanthrene 
 (C. 1905, I. 843). 
 
 Anthraquinone - sulphonic Acids. Heating anthraquinone with 
 fuming sulphuric acid produces a little i-anthraquinone-sulphonic acid, 
 but chiefly 2-anthraquinone-sulphonic acid, and on further sulphuration 
 2, 6- and 2, 7-acids are formed. On adding some finely divided 
 mercury salt to this sulphurated mixture, the i-acid is mostly produced, 
 with some i, 5- and i, 8-acid. i-Monosulphonic acid, sulphurated with 
 mercury salt, yields i, 6- and i, 7-disulphonic acid. Sulpho-groups in 
 the i-position, on being heated with NH 3 , or amines, are easily replaced 
 by NH 2 or NHR groups ; with methyl-alcoholic potash or potassium 
 phenolate they are replaced by CH 3 O or C 6 H 5 O groups ; and on 
 heating with lime-water under pressure by HO groups (B. 36, 4194 ; 37, 
 66, 331, 646). On fusing with potash these acids, which contain the 
 
ANTHRACENE GROUP 713 
 
 sulpho-groups in the 2-position, yield both normal and higher hydroxyl- 
 ated products : 
 
 / > 2-Oxy-anthraquinone 
 2-Anthraquinone-monosulphomc acid ^ ^ Alizarin (i 2 OH) 
 
 f > Anthra-flavinic acid (2, 6 OH) 
 2, 6-Anthraqninone-disulphonic acid -^ Flavo . purpurin (l> 2 6 O H) 
 
 / > Iso-anthra-flavinic acid (2, 7 OH) 
 2, 7-Anthraqumone-disulphomc acid - ^ Anthra . purpurin (l , 2 , 7 OH) etc. 
 
 The sulpho-acids of the amido-alkyl-amido- and aryl-amido-anthra- 
 quinones are to a great extent valuable wool-dyes, e.g. alizarin 
 
 saphirol NH a [8]SO3H[6]OH[5]C 6 H<^^^>c 6 H[i]OH[2]SO 3 H[4]NH 2 , obtained 
 by reduction of dmitro-anthrarufin-disulphonic acid ; alizarin pure 
 blue c 6 H 4 <^^C c H[i]NH 2 [2]Br[4]NHC 7 H 6 S0 3 H, alizarin-cyanin green, 
 
 anthraquinone green, and many others. They are formed mostly 
 by transformation of a-halogen, or a-nitro- or a-oxy-anthraquinones, 
 with ammonia, or aliphatic or aromatic amines, and subsequent 
 sulphuration (B. 34, 2344 ; C. 1904, II. 339). 
 
 A summary of the literature of the anthraquinone-sulphonic acids 
 and their derivatives is found in Chemische Industrie, 32, 477. 
 
 The oxy-anthraquinones are derived (i) from the bromo- and chloro- 
 anthraquinones and from the sulphonic acids on fusion with alkalies, 
 when the substituting groups are replaced by hydroxyls. 
 
 By stronger fusion there generally ensues an additional entrance of 
 hydroxyl (oxy- and dioxy-anthraquinones result from the mono- 
 sulphonic acids) ; the same is true in the fusion of the oxy-anthra- 
 quinones (B. 11, 1613). 
 
 (2) The oxy-anthraquinones may be synthetically prepared on 
 heating phthalic anhydride with phenols (mono- and poly-valent) and 
 sulphuric acid to 150. The m-oxy-benzoic acids and oxy-benzoyl-o- 
 benzoic acids also yield them when similarly treated (C. 1908, I. 1697). 
 
 The introduction of hydroxyl into anthraquinone and the oxy- 
 anthraquinones can be effected practically by persulphates in sulphuric 
 acid solution. One or several hydroxyl groups will then enter the 
 anthraquinone molecule, depending upon the conditions which 
 prevail (B. 29, R. 988). 
 
 Continued fusion with alkalies causes the oxy-anthraquinones to 
 separate into their component oxy-benzoic acids (in the same way as an- 
 thraquinone decomposes into benzoic acid), and this reaction aids in the 
 determination of the position of the isomerides (B. 12, 1293 ; A. 280, i). 
 
 Oxy-anthraquinones are reduced to anthracene when heated with 
 zinc dust. 
 
 Individual hydroxyls in the oxy-anthraquinones are reduced by 
 heating the latter with stannous chloride and sodium hydroxide (A. 183, 
 216). Heated to I5o-2oo with ammonia water, single OH groups 
 are replaced by amide groups. 
 
 During the etherification of the oxy-anthraquinones a striking rule 
 is observed, recalling the etherification of the benzoic acids. Only the 
 hydroxyls in the j8-position, but not those in the a-position, are etherified 
 on treatment with halogen alkyls or dialkyl sulphate and alkali. This 
 behaviour has been used successfully for determinations of constitution. 
 
714 ORGANIC CHEMISTRY 
 
 The oxy-anthrones and oxy-anthracenes show no such impediment to 
 reaction (A. 349, 201). 
 
 (a) Monoxy-anthraquinones C 14 H 7 O 2 (OH) the a- or erythro-oxy- 
 anthraquinone, melting at 190, and the /3- at 323, are formed 
 simultaneously on heating together phenol and phthalic anhydride. 
 The jS-body is also prepared from jS-bromo- or sulpho-anthraquinone. 
 
 Both oxy-anthraquinones yield alizarin when fused with caustic 
 potash. 
 
 (b) Dioxy-anthraquinones. The members of this group containing 
 two OH groups in the I, 2-position are especially interesting, because 
 they unite with metallic oxides to form insoluble, very stable lakes, 
 which adhere closely to the fibre. Their colour varies with the char- 
 acter of the metal. They are, therefore, very valuable mordant dyes 
 (B. 21, 435, 1164) (compare the similar behaviour of the dioxy-benzo- 
 phenones, and naphthazarin, etc. For the theoretical side, consult 
 B. 26, 1574). Alizarin, i, 2-dioxy-anthraquinone, is the most im- 
 portant of these dyes. 
 
 Nine of the ten possible isomeric dioxy-anthraquinones are known. 
 
 Alizarin, i, 2-dioxy-anthraquinone, melting at 290 and subliming at 
 higher temperatures in orange-red needles, is the chief constituent of 
 the dye of the madder root (Rubia tinctorium), in which it is contained 
 as ruberythric acid (identical with morindin, from Morinda citrifolia). 
 
 Through the action of a ferment in the madder root, or when it is 
 boiled with dilute acids or alkalies, ruberythric acid decomposes into 
 glucose and alizarin : 
 
 Ruberythric acid C 26 H 28 O 14 +2H 2 O=2C 6 H 12 O 6 +C U H 6 O 2 (OH)2 Alizarin. 
 
 The alizarin products (garancin, etc.) obtained by such decomposi- 
 tions of madder root were formerly used in dyeing. At present they 
 have been almost entirely supplanted by pure synthetic alizarin. 
 
 Artificial alizarin was first obtained by Graebe and Liebermann, in 
 1868, by heating dibromo-anthraquinone with potassium hydroxide. 
 They had previously observed that the natural alizarin yielded anthra- 
 cene when it was heated with zinc dust. Alizarin is also produced from 
 dichloro- and monobromo-anthraquinone, from the two oxy-anthraquin- 
 ones and anthraquinone-sulphonic acid, by fusion with caustic potash. 
 
 Technically, it is made from anthraquinone prepared from purified 
 (50 per cent.) anthracene. The latter is converted by fuming sulphuric 
 acid into anthraquinone-monosulphonic acid, which is then fused under 
 pressure for several days with caustic soda at a temperature ranging 
 from i8o-20O. Potassium chlorate is added as an oxidising agent. 
 The product of the reaction is sodium-alizarin, which is then decom- 
 posed with hydrochloric acid and brought into the market in the form 
 of a paste (10-20 per cent.). 
 
 Alizarin also results, together with isomeric hystazarin, on heating 
 phthalic anhydride with pyro-catechin and sulphuric acid. 
 
 Alizarin dissolves readily in alcohol and ether, and sparingly in hot 
 water. It dissolves with a purple-red colour in the alkalies ; lime and 
 barium salts throw out the corresponding salts as blue precipitates. 
 Alums and tin salts produce red-coloured precipitates (madder lakes) ; 
 while ferric salts form blackish-violet, and chromium salts violet-brown 
 precipitates. 
 
ANTHRACENE GROUP 715 
 
 In cotton dyeing and printing the beautiful red lake and the almost 
 black iron lake are generally employed. The goods are mordanted with 
 alumina (by immersing them in aluminium acetate and then heating, 
 whereby aluminium hydroxide is deposited on the fibres) and then 
 dipped into the solution of alizarin ; the resulting alizarin aluminate 
 is fixed by the fibres. In dyeing with turkey-red it is customary to 
 mordant the cloth with oil and alum, when the alumina then unites 
 both with the oleic acid and with the alizarin. 
 
 Alizarin is decomposed by protracted fusion with caustic potash into 
 benzoic and proto-catechuic acids. 
 
 Alizarin-dimethyl ether C 14 H 6 O 2 (OCH 3 ) 2 , m.p. 215, results from 
 i, 2-dimethoxy-anthrone on oxidation, and from i-nitro-2-methoxy- 
 anthraquinone by heating with methyl-alcoholic potash. On saponi- 
 fication with concentrated H 2 SO 4 it yields the alizarin-2-monomethyl 
 ether, m.p. 230, also obtained by direct methylation of alizarin (A. 349, 
 201). The isomeric alizarin-1-monomethyl ether, m.p. 179, hitherto 
 unobtainable by synthesis, is found, besides hystazarin-monomethyl 
 ether and anthragallol-i, 2-, and -i, 3-dimethyl ether, in the root of 
 Oldenlandia umbellata (" chaz root ") (C. 1908, I. 646). 
 
 jS-Nitro-alizarin, alizarin orange C 6 H 4 (CO) 2 C 6 H(OH) 2 (3)NO 2 , consists 
 of orange-red leaflets, melting at 244. It is produced by nitrating 
 alizarin in glacial acetic acid or by the action of NO 2 vapours. It is 
 prepared technically. Its alumina lake is orange in colour. 
 
 The jS-amido-alizarin obtained by the reduction of /2-amido-alizarin 
 forms with acetic anhydride an anhydro-base, and therefore contains 
 the NH 2 group in the o-position with respect to an OH group (B. 18, 
 1666; 35,906). 
 
 Alizarin blue, a derivative of anthraquinolin (B. 18, 447), results 
 upon heating it with glycerol and sulphuric acid. (See Skraup's quino- 
 lin synthesis) (B. 18, 447). The isomeric a-nitro-alizarin C 6 H 4 (CO) 2 
 C 6 H(OH) 2 [4]NO 2 , m.p. 195, is formed by nitrifying diacetyl-alizarin 
 (cp. B. 24, 1610). The a-amido-alizarin obtained by reduction gives, 
 with glycerin, nitre-benzol, and sulphuric acid, a green dye, alizarin 
 green, isomeric with alizarin blue. 
 
 l-Oxy-2-amido-anthraquinone, alizarin amide C 14 H 6 O 2 (OH)NH 2 , 
 m.p. 225, is obtained by heating alizarin with ammonia water to 200 
 (B. 39, 1201). 
 
 Amido-oxy-anthraquinones can also be prepared from the hydroxyl- 
 amido - anthraquinones obtained by the -reduction of nitro-anthra- 
 quinones, by transposing them with sulphuric acid (B. 29, 2934 ; 35, 
 666) ; also by the action of fuming sulphuric acid upon amino- and 
 alkyl-amino-anthraquinones (C. 1904, II. 1013). Bromo-alizarin, see 
 B. 33, 1664. Alizarin-sulphonie acid, see C. 1909, II. 244. 
 
 Three of the dioxy-anthraquinones isomeric with alizarin contain 
 the OH groups in one benzene nucleus. They are : 
 
 (1, 3)-Purpuro-xanthin, from phthalic anhydride and resorcinol ; 
 (1, 4)-quinizarin, from hydroquinone ; and (2, 3)-hystazarin, from 
 pyro-catechin (B. 28, 116). They are prepared more advantageously 
 from their ethers, which result by the condensation of the corresponding 
 dioxy-benzene ethers with phthalic anhydride and A1 2 C1 6 (A. 342, 99). 
 Quinizarin is also formed in the action of concentrated sulphuric acid 
 and nitrous acid upon anthraquinone and i-oxy-anthraquinone, a 
 
716 ORGANIC CHEMISTRY 
 
 process in which the sulphate of i-oxy-4-diazo-anthraquinone could 
 be isolated, which, on further heating with sulphuric acid, splits up into 
 quinizarin and nitrogen (C. 1905, II. 184). On prolonged heating with 
 concentrated H 2 SO 4 , hystazarin is partly transposed into alizarin 
 (B. 35, 1778). For derivatives of hystazarin, see B. 30, 2936. 
 
 The following dioxy-anthraquinones containing their OH groups 
 in different benzene nuclei (hetero-nuclear) have been mostly obtained 
 from the corresponding disulpho-acids by heating with lime-water : 
 
 1, 5-Anthrarufin, 1, 6- and 1, 7-dioxy-anthraquinone, 1, 8-ehrysazin, 
 2, 6-anthraflavie acid. Iso-anthraflavie acid is obtained from j8- 
 anthraquinone-sulphonic acid. Chrysazin is another isomeride. It is 
 obtained from its tetranitro-compound C 14 H 2 (NO 2 ) 4 (O 2 )(OH) 2 , the so- 
 called chrysammic acid, by reduction and the replacement of the amido- 
 groups. This latter acid is obtained when aloes are digested with con- 
 centrated nitric acid. Consult B. 19, 2327, upon the spectra of the 
 dioxy-anthraquinones. 
 
 Homologous Dioxy-anthraquinones. Dioxy-methyl-anthraquinone 
 C 14 H 5 (CH 3 )O 2 (OH) 2 , is ehrysophanic or rheinie acid, melting at 178 
 (A. 284, 193). It exists in senna leaves (of the Cassia varieties) and in 
 the root of rhubarb (from the Rheum variety), together with methyl- 
 chrysophanic acid (A. 309, 32). Zinc dust reduces it to methyl-an- 
 thracene. 
 
 Chrysarobin C 30 H 36 O 7 , a reduction product of ehrysophanic acid, 
 occurs in goa- and arroroba-powder, a secretion of coloured Brazilian 
 woods. Air oxidises its alkaline solution to ehrysophanic acid. The 
 same occurs in the animal organism (B. 21, 447). 
 
 Methyl-alizarin, melting at 25o-252, is isomeric with dioxy- 
 methyl-anthraquinone. It is obtained from methyl-anthraquinone- 
 sulphonic acid. It is very similar to alizarin. 
 
 Various methyl-purpuro-xanthins have been prepared by the con- 
 densation of i, 3, 5-dioxy-benzoic acid with o- and m-toluic acids 
 (B. 29, R. 141). 
 
 By the condensation of 5-methyl-phthalic acid with pyro-catechin, 
 besides a methyl-alizarin, m.p. 216, a methyl-hystazarin (OH) 2 [6, 7] 
 C 6 H 2 (CO) 2 C 6 H 3 [2]CH 3 , has been obtained (B. 33, 1629). 
 
 Dimethyl-anthrarufln (CH 3 )(OH)C 6 H 2 (CO) 2 C 6 H 2 (CH 3 )(OH) can also 
 be obtained by the action of sulphuric acid upon sym. oxy-toluic acid 
 (B. 22, 3273). 
 
 (c) Trio%y-anthraquinones. These are produced on oxidising an- 
 thraquinone-disulphonic acids and dioxy-anthraquinones, or by fusing 
 them with alkalies. 
 
 Purpurin C 6 H 4 ^^c 8 H[i,2, 4 ](OH) 3 +H 2 o, melting at 253 (an- 
 hydrous) and sublimable, is present with alizarin in the madder root. 
 It is prepared artificially by heating alizarin and quinizarin with 
 manganese dioxide and sulphuric acid to 150. It is also obtained 
 from tribromo-anthraquinone. It dissolves with a pure red colour 
 in hot water, alcohol, ether, and the alkalies. Lime and baryta water 
 yield purple red precipitates. It yields a beautiful scarlet red with 
 alumina mordants. 
 
 Purpurin-amide C 14 H 5 O 2 (OH) 2 NH 2 is obtained on digesting pur- 
 purin with aqueous ammonia at 150. 
 
ANTHRACENE GROUP 717 
 
 The following are isomerides of purpurin : anthragallol (i, 2, 3), a 
 constituent of alizarin brown, anthra- or iso-purpurin (i, 2, 7), and 
 flavo-purpurin (i, 2, 6), applied technically in dyeing and printing, and 
 also oxy-ehrysazin (1,2,5?), oxy-anthrarufln (1,2,5) ( A - 349, 215) 
 and 1, 4, 8-trioxy-anthraquinone (C. 1905, II. 1142). Consult A. 280, i, 
 for the determination of the constitution of these bodies from the 
 decompositions of the disulphonic acids genetically connected with 
 them. 
 
 Homologous Trioxy-anthraquinones. Emodin, and a trioxy-methyl- 
 anthraquinone, melting at 203 and isomeric with it, are formed, together 
 with rhamnose, by the decomposition of frangulin, from the bark of 
 Rhamnus frangula, by means of alcoholic hydrochloric acid (B. 25, R; 
 371). Emodin also results from the decomposition of polygonine. 
 
 An isomeric emodin is aloe emodin, m.p. 224, which is found in 
 company with barbalo'in in many aloe species (C. 1898, II. 211) as well 
 as in senna leaves (C. 1900, II. 871). On oxidation with chromic acid 
 it passes into a dioxy-anthraquinone-carboxylic acid, the so-called 
 rhe'in, which has also been extracted from Chinese rhubarb (C. 1909, 
 II. 622). A trioxy-methyl-anthraquinone isomeric with emodin is 
 probably the mormdone, m.p. 272, obtained by splitting up morindin, 
 a glycoside from Morinda citrifolia. 
 
 (d) Tetra- and Poly-oxy-anthraquinones. When oxy-anthraquinones 
 are heated with fuming sulphuric acid, new hydroxyls enter these 
 bodies, para-hydrogen atoms of the non-substituted nucleus being re- 
 placed (/. pr. Ch. 2, 43, 231 ; 44, 103). Thus alizarin yields quin- 
 alizarin, alizarin-bordeaux Cj 4 H 4 2 -i, 2, 5, 8- (OH) 4 . 
 
 Two tetraoxy-anthraquinones, anthra-ehrysone and rufiopin, are 
 obtained by heating symmetrical dioxy-benzoic acid and opianic acid 
 or proto-catechuic acid with sulphuric acid. 
 
 Rufigallic acid is a hexaoxy-anthraquinone C 14 H 2 2 -i, 2, 3, 5, 6, 7- 
 (OH) 6 , which is formed when gallic acid is heated with sulphuric acid. 
 It dissolves with an indigo-blue colour in alkalies. 
 
 It dyes chrome-mordanted material brown. It appears in trade 
 in conjunction with anthra-purpurin as alizarin or anthracene brown. 
 Anthracene blue, formed by the action of fuming sulphuric acid upon 
 di-nitro-anthraquinone, is an isomeric hexaoxy-anthraquinone. 
 
 Anthraquinone-carboxylic acids. a- andjS-Anthraquinone-carboxylic 
 acids are produced in the oxidation of anthracene-carboxylic acids. 
 The a-acid (m.p. 285) is also formed in the condensation of benzoyl- 
 phthalic acid and iso-phthalic acid (B. 29, R. 284), and the j8-acid 
 when chromic acid acts upon methyl-anthracene. The amide of the 
 a-acid, treated with bromine and alkali, yields i-amido-anthraquinone 
 (B. 30, 1115). Trioxy - anthraquinone - earboxylie acid, purpurin- 
 carboxylic acid C 14 H 4 O 2 (OH) 3 CO 2 H, is pseudo-purpurin, which occurs 
 in crude purpurin (from madder). On heating it decomposes into 
 carbon dioxide and purpurin. 
 
 See C. 1894, II. 784, for the synthetic purpurin-carboxylic acids. 
 
 Dianthraquinoyls. This term is used to designate those compounds 
 in which two anthraquinone residues are directly joined in the a- or 
 jS-position. They are formed either on the analogy of diphenyl (i) from 
 the iodo-anthraquinones by heating with powdered copper ; (2) from 
 anthraquinone-diazonium sulphates with acetic anhydride and powdered 
 
7 i8 ORGANIC CHEMISTRY 
 
 copper (B. 40, 1697 ; C. 1909, II. 1906) ; or (3) on the analogy of an- 
 thraquinone synthesis by dehydrating the diphenyl-diphthaloyl acids, 
 obtained by heating diphenyl and phthalic anhydride in the presence 
 of A1C1 8 (B. 44, 1075) : 
 
 1, l'-Dianthraquinoyl, yellowish-brown needles, by methods i and 
 2 ; 2, 2'-dianthraquinoyl, m.p. 388, by i, 2, and 3 ; 2, 2'-dimethyl- 
 1, I'-dianthraquinoyl, m.p. 367 ; 2, 4, 2' 4'-tetramethyl-l, I'-dian- 
 thraquinoyl, m.p. 297 (B. 43, 512). 
 
 The dianthraquinoyls are distinguished by the fact that they can 
 be easily converted by a further fusion of the anthraquinone nuclei into 
 quinonoid compounds with highly condensed ring systems. Thus the 
 i, i-dianthraquinoyl, reduced with Cu or Ni powder and concentrated 
 H 2 SO 4 , yields meso-benzo-dianthrone (similar to meso-dianthrone), 
 steel-blue aggregates resembling haematite, and passing on heating with 
 A1C1 3 to I4o-i45 into meso-naphtho-dianthrone (see below), blue 
 needles, with rejection of 2H and further linking of two benzene nuclei 
 (B. 43, 1734). The 2, 2 / -dimethyl-i, I'-dianthraquinoyl condenses, 
 on heating alone, to 35o-38o, or, better, by boiling with concentrated 
 alcoholic potash and rejection of 2H 2 O to pyranthrone, reddish-brown 
 needles, which resembles flavanthrene in its structure and is related 
 to it, as is anthraflavone to indanthrene (B. 43, 346) : 
 
 CO 
 
 X/VV 
 
 \/ s 
 
 co Co co 
 
 Meso-benzo-dianthrone Meso-naphtho-dianthrone Pyranthrone. 
 
 The three compounds all possess the character of vat dyes. Pyran- 
 throne more particularly is known as a specially permanent orange dye 
 under the name of " indanthrene gold-orange." 
 
 Benzanthrones. On heating anthraquinone or, better, anthrone 
 with glycerin and concentrated sulphuric acid to ioo-no, we obtain 
 the so-called benzanthrone with attachment of a new benzene ring in the 
 i, 9-position (B. 38, 170) : 
 
 C 6 H 4 .CH 2 HOCH 2 \ 
 C 
 
 2 \ 
 2 / 
 
 _ 
 CO C 6 H/ HOCH 2 / I^H - CO C 6 H 3 .CH 
 
 From the amido-anthraquinone we obtain, with simultaneous 
 formation of a ring containing nitrogen, benzanthrone-quinolins. 
 
 Benzanthrone (formula above), light-yellow needles, m.p. 170 ; 
 2-methyl- and 2, 4-dimethyl-benzanthrone, m.p. 199 and 165. 
 
 On fusing with caustic potash the benzanthrones, except the oxy-, 
 nitro-, and amido-benzanthrones, close up two molecules and form ex- 
 
ANTHRACENE GROUP 719 
 
 cellent vat dyes with a structure resembling pyranthrone and of a blue 
 or violet colour. They are called violanthrenes and iso-violanthrenes. 
 To these belong indanthrene dark blue, and its isomers and substitution 
 products indanthrene violet and indanthrene green. 
 
 yCHL 
 
 Naphthanthracene C 6 H 4 <^ j ^>C 10 H 8 , melting at 141, is isomeric with 
 
 chrysene. It is formed when its quinone is digested with zinc dust and 
 ammonia. 
 
 Naphthanthraquinone C 6 H 4 (CO) 2 C 10 H 6 , melting at 168, is obtained 
 
 /{^(~*\(~\\ T 
 
 from naphthoyl-o-benzoic acid C 6 H \ CO c H , the same as anthra- 
 
 quinone from benzoyl-benzoic acid (B. 19, 2209 ; 29, 827). 
 
 Naphthanthraquinone is split up by melting with potash into j8- 
 naphthoic acid and benzoic acid (B. 19, 2209 ; 29, 827 ; 33, 446). Phen- 
 anthro-anthraquinone C 14 H 3 (CO) 2 C 6 H 4 , m.p. 234, see C. 1908, 1. 1223. 
 
 or 
 
 is isomeric with naphth anthracene ; it is formed from its oxygen deriva- 
 tives oxy- and dk xy-naphthacene-quinone by distillation with zinc dust. 
 
 to 
 
 m 
 
 ,co. HC - c-v 
 .p. 347, red flakes, from ethindiphtalyl C 9 uS \O \ o/ ^>C 6 H 4 
 
 ^C CH \CCr 
 by transposition with sodium methylate, or by the oxidation of diketo- 
 hydrindene with potassium persulphate; by oxidation with HNO 3 
 
 we obtain naphthacene-di-quinone c H *<(o''ro)> c H > m -P- 333 which 
 
 reverts very easily into the dioxy-naphthacene-quinone ; by reduction 
 of the latter with phosphorus and HI we obtain dihydro-naphthaeene 
 C 18 H 14 , m.p. 207, which with chromic acid yields naphthacene-quinone 
 C 10 H 6 (CO) 2 C 6 H 4 , m.p. 294, an isomer of naphthanthraquinone (B. 31, 
 1272 ; 33, 446). By condensation of phthalic anhydride and a-naph- 
 thol, or of a-oxy-naphthoyl-o-benzoic acid with boric acid and sulphuric 
 
 acids, we obtain monoxy-naphthacene-quinone C 6 H 4 /J: '] fC 10 H 5 [i]OH, 
 
 \L/UL3J J 
 
 m.p. 303, which, on oxidation, easily passes into the above dioxy- 
 naphthacene-quinone, and can be converted by reduction into 
 naphthacene and dihydro-naphthacene (B. 36, 547, 719, 2326). 
 
 VI. GLYCOSIDES OR GLUCOSIDES AND PENTOSIDES. 
 
 Glycosides or glucosides are those vegetable substances which break 
 down into sugars, chiefly grape sugar or glucose, and other bodies, when 
 they are exposed to the action of unorganised ferments or enzymes (1-587) . 
 Some of them decompose into iso-dulcite or rhamnose, a pentose, hence 
 they are designated as pentosides. In many glycosides the exact nature 
 of the sugar is not known. The glycosides and pentosides are therefore 
 to be regarded as ethereal sugar derivatives. Some of them were de- 
 scribed under their decomposition products, while many have been 
 synthesised. 
 
 E. Fischer demonstrated that the simplest glucosides could be pre- 
 
720 ORGANIC CHEMISTRY 
 
 pared by the action of hydrochloric acid upon alcoholic sugar solutions ; 
 they have been described in Vol. I. 
 
 A second method of forming artificial glucosides, due to Michael, 
 is based upon the mutual action of phenols and aceto-chloro- or bromo- 
 glucose (Vol. I.) in alkaline-alcoholic solution. 
 
 la. Sinigrin, potassium myronate C 10 H 18 NS 2 O 10 K=C3H B N : C 
 
 . 6u5 
 
 +H 2 O, m.p. 127 (anhydrous, 132), is found in black mustard-seed and 
 in the root of Cochlearia armoracia. It crystallises from water in brilliant 
 needles. On boiling with baryta water, or by the action of the ferment 
 myrosin, contained in mustard-seed, it is split up into d-glucose, allyl- 
 mustard oil, and primary potassium sulphate (B. 30. 2322). 
 
 OS0 2 .O.C 16 H 24 N0 5 
 ib. Sinalbin C3 H 44 N 2 s 2 o 16 =c^sc 6 H n o 6 +H 2 o (?) is found 
 
 ^N.CH 2 C 6 H 4 OH 
 
 in white mustard - seed. Myrosin decomposes it into glucose, 
 sinalbin-mustard oil, and p-oxy-benzyl-mustard oil SC : NCH 2 C 6 H 4 
 [4] OH and sinapin sulphate Ci 6 H 24 NO 5 .HSO 4 . Sinapin easily splits 
 up into cholin (Vol. I.) and sinapic or oxy-dimethoxy-cinnamic acid 
 (CH 3 0) 2 [ 3 , 5](OH)[ 4 ]C 6 H 2 CH : CH.COOH (B. 30, 2327). 
 
 A constitution resembling that of sinalbin may also be possessed by 
 the glucosides of various cresses, such as Tropceolwm majus, Lepidium 
 sativum, and Nasturtium officinale, which, on splitting up, give benzyl- 
 ethyl and phenyl-ethyl-mustard oil, instead of allyl-mustard oil (B. 32, 
 
 2335). 
 
 2. Arbutin C 12 H 16 7 and methyl arbutin C 13 H 18 O 7 are found in the 
 leaves of Arbutus uva ursi. Arbutin crystallises in fine needles, with 
 J-i molecule of water, and melts at 187 (B. 16, 800) in the anhydrous 
 state. Methyl arbutin melts at 176. It is formed artificially from 
 arbutin by the action of methyl iodide and potash. 
 
 By their decomposition we get, besides grape sugar, hydroquinone 
 or methyl-hydroquinone : 
 
 C 12 H 16 7 +H 2 0=C 6 H 12 6 +C 6 H 4 (OH) 2 . 
 
 3. Salicin C 6 H n O 6 .O.C 6 H 4 CH 2 OH, m.p. 201, saligenin glucose, 
 occurs in the bark and leaves of willows e.g., Salix helix and some 
 poplars, from which it may be extracted with water. It can be artifici- 
 ally prepared by reducing helicin with sodium amalgam. It forms 
 shining crystals, which dissolve easily in hot water and alcohol. Its 
 taste is bitter. 
 
 Oxidants convert it into helicin, hence the saligenin in salicin is 
 linked by means of the phenol-oxygen atom with the glucose. The 
 enzymes ptyalin and emulsin (Vol. I.) decompose salicin into glucose 
 and saligenin : 
 
 C 6 H n O 5 -O.C 6 H 4 .CH 2 .OH+H 2 O=C 6 H 12 O 6 +HO.C 6 H 4 .CH 2 .OH. 
 
 Boiling dilute acids decompose it in a similar manner, but in so 
 doing the saligenin is changed to saliretin. 
 
 Salicin was discovered almost simultaneously by Leroux (1830) 
 and Buchner, and its composition was cleared up by Piria in 1845 
 (A. 56, 35). 
 
 Populin, the benzoyl derivative of salicin C 13 H 17 (C 7 H 5 O)O 7 +2H 2 O, 
 
GLYCOSIDES OR GLUCOSIDES 721 
 
 occurs in the bark and leaves of Populus tremula. It can also be arti- 
 ficially made by the action of benzoic anhydride or benzoyl chloride 
 upon salicin. 
 
 Helicin, salicyl-aldehyde-glucose C6H 4 (O.C 6 H n O 5 ).CHO, is pro- 
 duced by oxidising salicin with nitric acid. It reverts to salicin upon 
 reduction. It can be artificially prepared from salicylic aldehyde and 
 aceto-chloro-hydrose. It is broken down just like salicin by ferments 
 or dilute acids. 
 
 Glucose-cumaraldehyde C 6 H n O 5 .O.C 6 H 4 .CH=CH.CHO and 
 Methyl-gluco-o-cumar-ketone result from the condensation of helicin 
 with acetaldehyde and acetone (B. 24, 3180). 
 
 4. Gem C 6 H 22 O 7 is found in the root of Geum urbanum. It splits 
 up into glucose and eugenol (C. 1905, I. 1329). 
 
 5. Gaultherin C 6 H n O 5 O.C 6 H 4 COOCH 3 -f-H 2 O is found in numerous 
 species of Gaultheria and Spircea, also in Betula lenta, besides an 
 enzyme " gaultherase," by which it is split up into glucose and salicylic 
 methyl ester. 
 
 6. Coniferin C 16 H 22 O 8 4-2H 2 O is found in the cambium of coniferous 
 woods, in asparagus, and in the black root of Scorzonera hispanica 
 (B. 25, 3221). It effloresces in the air, and melts at 185. It acquires 
 a dark-blue colour when moistened with phenol and hydrochloric acid. 
 Boiling acids or emulsin decompose it into glucoses and coniferyl 
 
 alcohol C 6 H 3 (^ H3 Yc 3 H 4 .OH, which is oxidised by chromic acid to : 
 
 Glyco-vanillin C 6 H3(O.CH3)(O.C 6 H n O 5 ).CHO, the glucoside of 
 vanillin, melting at 192. Acids or emulsin split it up into glucoses and 
 vanillin (B. 18, 1595, 1657). 
 
 Syringin, methoxyl - coniferin C 17 H 24 O 9 +H 2 O=C 6 H n 5 .O.C 6 H 2 
 (OCH 3 ) 2 C 3 H 4 OH, occurs in the bark of Syringia vulgaris and Ligustrum 
 vulgare. It melts at 191 and shows changes similar to those of 
 coniferin. 
 
 7. Phlorizin C 21 H 24 O 10 , melting at 108, occurs in the root-bark of 
 various fruit trees ; hence the name, from ^Aotos-, bark, and pi^a, root. 
 It is intimately related to the pentosides : naringin and hesperidin. 
 It breaks down into grape sugar and phloretin, the phloro-glucin ester 
 of p-oxy-hydratropic acid, and the latter into phloro-glucin and 
 phloretic acid : 
 
 C 21 H 24 O 10 +H 2 O=C 6 H 12 O 6 (Glucose) +C 15 H 14 O 2 (Phloretin) 
 
 c i 5 H 14 O 5 +H 2 O=C 6 H 6 O 3 (Phloro-glucin) +C 9 H 10 O 3 (Phloretic acid). 
 
 Administered internally, it produces strong glucosuria. 
 
 8. lseulin C 15 H 16 O 9 +iH 2 O melts at about 205 when it is 
 anhydrous. It is found in the horse-chestnut, Jisculus hippocastanum, 
 and in the root of the wild jasmine, Gelsemium sempervirens. Acids or 
 ferments resolve it into glucose and aesculetine or 4, 5-dioxy-cumarin. 
 
 9. Daphnin C 15 H 16 O 9 +2H 2 O, melting at 200, is isomeric with the 
 preceding. It is obtained from the bark of Daphne alpina. It breaks 
 down into glucose and daphnetin or 3, 5-dioxy-cumarin. 
 
 10. Fraxin C 16 H 18 O 10 occurs in the bark of Fraxinus excelsior, and, 
 like sesculin, in the bark of the horse-chestnut. It decomposes into 
 glucose and fraxetin, the monomethyl ether of a trioxy-cumarin (B. 
 27, R. 130). 
 
 VOL. II. 3 A 
 
722 ORGANIC CHEMISTRY 
 
 11. Iridin C 24 H 26 13 , melting at 208, occurs in the root of the 
 violet, Iris florentina, etc. Dilute sulphuric acid resolves it into grape 
 sugar and irigenin C 18 H 16 O 8 . The latter is probably a poly oxy-ket one. 
 Concentrated caustic alkali decomposes it into formic acid, an aromatic 
 oxy-acid iridic acid C 10 H 12 O 6 , melting at 118, which, by loss of CO 2 , 
 becomes iridol or 3-oxy-4, 5-dimethoxy-i-methyl-benzene, melting at 
 57 and iretol C 7 H 8 O 4 , or methoxy-phloroglucin, melting at 186 
 (B. 26, 2010 ; 27, R. 514). 
 
 12. Ruberythrie acid C 26 H 28 O 14 =HO.C 14 H 6 O 2 .O ; C 12 H 14 O 3 (OH) 7 , 
 melting at 258-26o, is the glucoside of alizarin. It is formed in the 
 madder root of Rubia tinctorum, and breaks down under the influence 
 of hydrochloric acid into alizarin and glucose (B. 20, 2244). Purpurin 
 is also contained in the madder root as a glucoside. 
 
 13. Saponarin C 21 H 24 O 12 is found in Saponaria officinalis. Boiling 
 witrTdilute mineral acids splits it up into glucose and vitexin C 15 H 14 O 7 . 
 The latter, probably a flavone derivative, gives, on boiling with potash, 
 phloro-glucin and p-oxy-aceto-phenone (C. 1906, II. 1062). 
 
 14. Digitalin (Digitalinum verum, Kiliani) C 35 H 56 O 14 (?) is an 
 amorphous glucoside. It is the active principle of the digitalis gluco- 
 sides, which occur in the leaves of Digitalis purpurea and lutea. Con- 
 centrated hydrochloric acid breaks it down into digitaligenin C 16 H 22 O 2 , 
 grape sugar C 6 Hi 2 O 6 , and digitalose C 7 H 14 O 5 . 
 
 Its therapeutic action consists in its occasioning " less frequent but 
 more satisfactory heart contractions." * 
 
 The chief ingredient of the digitalis glycosides is without thera- 
 peutic action. It is crystalline digitonin C 27 H 44 O 13 , which is resolved 
 by aqueous alcoholic hydrochloric acid into digitogenin C 15 H 24 O 4 , 
 glucose, and galactose. The decomposition of the latter has led to a 
 series of acids, the constitution of which is as yet undetermined (B. 27, 
 R. 881 ; 28, R. 1056 ; 31, 2454 ; 32, 2201 ; 37, 1215 ; and 43, 3562). 
 
 From the leaves of Digitalis purpurea another pharmaceutically 
 effective glucoside is obtained, called digitoxin C 34 H 54 O n m.p. 145, 
 which is split up by HC1 into digitoxose C 6 H 12 O 4 (two molecules) 
 and digitoxigenin C 22 H 32 O 4 (?). Besides digitoxin we find a small 
 quantity of a yellow pigment, the so-called digito-flavone C 15 H 10 O 6 , 
 which belongs to the group of the flavones (q.v.), and is identical with 
 luteolin (B. 32, 2196, 1184 ; 34, 3577). 
 
 15. Saponin C 32 H 54 O 18 , from the root of Saponaria officinalis, is a 
 white amorphous powder, which provokes sneezing and foams in 
 aqueous solutions. Its decomposition yields glucose and sapogenin 
 C 14 H 22 2 (B. 42, 238). 
 
 16. Convolvulin C 31 H 50 O 16 , from the jalapa root of Convolvulus purga y 
 is a gummy mass, which is a powerful purgative. Among its decom- 
 position products are, in addition to a sugar, d-methyl-ethyl-acetic 
 acid and an oxy-pentadecylic acid C 2 H 5 CH(CH 3 ).CH(OH)C 9 H 18 .CO 2 H, 
 melting at 50. Nitric acid oxidises the latter to methyl-ethyl-acetic 
 acid and an acid C 10 H 18 O 4 (B. 27, R. 885), melting at 116, isomeric 
 with sebacic acid (B. 27, R. 885 ; C. 1901, I. 1042 ; II. 425, 426). 
 
 17. Jalapin, scammonin C 34 H 58 O 16 , from Convolvulus orizabensis, and 
 from scammonium resin, yields acetic acid, tiglic acid, and palmitic 
 acid upon distillation (B. 26, R. 591 ; 27, R. 736). 
 
 * Binz, Gvundzuge der Arzneimittellehre, p. 52. 
 
PENTOSIDES 723 
 
 18. Polygonin C 21 H 20 O 5 , melting at 203, is a glycoside, and has 
 been obtained from the root bark of Polygonum cuspidatum. It yields 
 emodin when it is decomposed with alcoholic hydrochloric acid (B. 
 29, R. 86). 
 
 19. Amygdalin, mandelo-nitrile di glucose 
 C 20 H 27 NO n + 3 H 2 : C.H.CH.CN 
 
 occurs in bitter almonds and in the 
 O.C 12 H 21 10 
 
 kernels of Pomaceae and Amygdalaceae, as well as in cherries, peaches, 
 apricots, and the leaves of the cherry tree. Amygdalin crystallises 
 from alcohol in white shining leaflets, and dissolves readily in water 
 and hot alcohol. 
 
 History, Amygdalin was discovered in 1830 by Robiquet and 
 Boutron-Chalard (^4. Chim. Phys. 2, 44, 351). The composition and 
 nature of amygdalin were cleared up by Liebig and Kohler (A. 22, i). 
 
 On boiling with dilute acids, or upon standing with water and 
 emulsin, an enzyme present in bitter almonds, amygdalin, is decom- 
 posed into oil of bitter almonds, dextrose, and hydrocyanic acid. 
 
 Yeast splits off only one molecule of glucose from amygdalin, and 
 we thus obtain 1-mandelic nitrile glucoside C 6 H5CH(CN).O.C 6 H n O 5 , 
 m.p. 148, which is decomposed by emulsion with intermediate forma- 
 tion of d-mandelic nitrile into benzaldehyde, prussic acid, and d-glucose, 
 and, on saponification with concentrated HC1, yields l-mandelic acid, 
 together with glucose and ammonia (B. 28, 1508). For lauro-cerasin, 
 see C. 1885, 570. Other glucosides are prulaurasin (C. 1907, II. 1340), 
 sambunigrin (C. 1907, II. 69), durrhin, linamarin, and virianin. 
 
 Pentosides, Rhamnosides. The following pentosides are to be 
 regarded as ethereal compounds of rhamnose C 6 H 14 O 6 =C 6 H 12 O 5 +H 2 O 
 (I. 536), or of iso-dulcite : 
 
 1. Naringin C 21 H 26 O n +4H 2 O, melts when anhydrous at 170. It 
 is found chiefly in the blossoms and also in other parts of the tree 
 Citrus decumana of Java. The name of the pentoside is derived from 
 " naringi," a Sanscrit word meaning orange. Dilute acids decompose 
 it into rhamnose and naringenin, melting at 230. The latter is the 
 phloro - glucin ether of p - oxy - cinnamic acid, which concentrated 
 caustic potash breaks down into phloro-glucin and p-cumaric acid 
 (B. 20, 296) : 
 
 C 21 H 26 O n =C 6 H 14 6 (Rhamnose) +C 15 H 12 O 5 (Naringenin) 
 C 15 H 12 O 5 -fH 2 O=C 6 H 6 O 3 (Phloro-glucin) +C 9 H 8 O 3 (p-Cumaricacid). 
 
 2. Hesperidin C 50 H 60 O 22 (?), melting at 251, is present in unripe 
 oranges, lemons, etc. It decomposes, when heated, into glucose, 
 rhamnose, and hesperetin, melting at 226. Caustic potash resolves 
 the latter into phloro-glucin and iso-ferulic acid (B. 14, 948) : 
 
 C 50 H 60 O 27 +3H 2 O=2C 6 H 12 O 6 +C 6 H 14 O 6 (Rhamnose) +2C 16 H 14 O 6 (Hesperetin). 
 C 16 H 14 O 6 + H 2 O=C 6 H 6 O 3 (Phloro-glucin) +C 10 H 10 O 4 (Iso-ferulic acid). 
 
 3. Quercitrin C 21 H 22 O 12 is present in the bark of Quercus tinctoria, 
 and is applied under the name quercitrone as a yellow dye. It breaks 
 down into rhamnose and quercetrin (see this), a phenyl-benzo-pyrene 
 derivative (B. 26, R. 234 ; 28, 2303) : 
 
 C 21 H 22 12 +H 2 0=C 6 H 14 6 (Rhamnose) +C 15 H 60 7 (Quercetrin). 
 
724 ORGANIC CHEMISTRY 
 
 4. Frangulin C 21 H 20 O 9 , melting at 286, occurs in the bark of 
 Rhamnus frangula. When it is saponified with alcoholic hydrochloric 
 acid rhamnose, emodin and a trioxy-methyl-anthraquinone, isomeric 
 with the latter, are produced (B. 25, R. 370) : 
 
 C 21 H 20 O 9 +2H 2 O=C 6 H 14 O 6 (Rhamnose) +C 15 H 10 O 5 (Emodin). 
 
 5. Aloin. Several apparently different aloins : aloin, barbaloin, 
 nataloin, are found in aloes, the dried juice of various species of aloe. 
 The best known is barbaloin, isolated from Barbadoes aloes, occurring 
 in yellowish needles, C 14 H 5 O 2 (OH) 2 CH 2 .O.C 6 H n O 4 (?) (C. 1909, II. 622). 
 On heating with aqueous alcoholic HC1 it is split up into an aldo- 
 pentose (osazone, m.p. 209) and aloe-emodin, and therefore shows 
 the same transformations as the latter (C. 1910, I. 104). Chromic 
 acid oxidises it to rhein, a dioxy-anthraquinone-carboxylic acid (above) ; 
 with HNO 3 chrysamic acid is obtained, and the so-called aloetic acid, 
 probably a mixture of several highly nitrated aloe-emodins. 
 
 VII. BITTER PRINCIPLES. 
 
 Under the head of " bitter principles," or indifferent substances, is 
 embraced a class of vegetable bodies many of which have already 
 found their place in the chemical system. Those yet uninvesti- 
 gated are : 
 
 Cantharidin C 10 H 12 O 4 , melts at 218 and sublimes readily. It is 
 contained in Spanish flies and other insects. It tastes very bitter, and 
 produces blisters on the skin. It dissolves when heated with alkalies 
 and forms salts of cantharinic acid C 10 H 14 O 5 . It combines with phenyl- 
 hydrazin to an addition product C 16 H 20 N 2 OH, melting at 194, and a 
 phenyl-hydrazone, melting at 238 (B. 26, 140). Cantharidin is pro- 
 bably a lactone-carboxylic acid. Hydriodic acid converts Cantharidin 
 into cantharic acid C 10 H 12 O 4 =C 8 H n O.CO.CO 2 H, isomeric with it. 
 When this acid is distilled with lime, cantharene or dihydro-o-xylene 
 results. 
 
 Anemonin C 10 H 8 O 4 , m.p. 150, appears to be closely related to 
 Cantharidin. It is a crystalline constituent of the extracts of nearly 
 all Anemones and Ranunculacece (M. 20, 634). 
 
 Pier o- toxin C 15 H 16 O 6 +H 2 O is found in the grains of cockle, and 
 crystallises in fine needles, melting at 201. It has an extremely 
 bitter taste, and is very poisonous. 
 
 It is a mixture of two bodies : picro-toxinin C 15 H 16 O 6 +H 2 O, m.p. 
 201, and picrotin C 15 H 18 O 7 , m.p. 249, which are best separated by 
 bromination in aqueous solution. In this case only the picro-toxinin 
 is brominated to sparingly soluble bromo-picro-toxinin, which can 
 then be reduced to picro-toxinin ; the latter is a strong reducing agent, 
 contains two hydroxyl groups, and seems to be a lactone (B. 31, 2958). 
 
 Santonin C 15 H 18 O 3 , melting at 170, [a] D = 171-37, is the active 
 principle of artemisia cina. It dissolves in alkalies to salts of santonic 
 acid C 15 H 20 O 4 , which breaks down at 120 into water and santonin. 
 On boiling with baryta water we obtain salts of isomeric santoic acid 
 C 15 H 20 O 4 , which melts at 171. 
 
 This acid, upon further oxidation, yields a tetracarboxylic acid. 
 For its constitution, see B. 29, R. 1119. Santonin is a lactone. It 
 
BITTER PRINCIPLES 725 
 
 bears the same relation to santonic and santoic acids as cumarin to 
 cumarinic and cumaric acids. Again, it contains the ketone group ; 
 its phenyl-hydrazone melts at 220. When santonin is reduced with 
 hydriodic acid or with stannous chloride and hydrochloric acid, santous 
 acid C 15 H 20 O 3 results. This is dextro-rotatory and melts at 179. The 
 corresponding laevo-rotatory modification and the (d-j-l)-acid are known. 
 When these three acids are fused with caustic potash, propionic acid, 
 dimethyl-j3-naphthol, and hydrogen are produced. Hence it would 
 seem that santonin is a derivative of a hexahydro-dimeihyl-naphthalene 
 (B. 27, 530 ; 28, R. 392 ; 29, R. 291, 296). When santonin is reduced 
 with tin and hyolrochloric acid, not only santous acid is formed, but also 
 a hydrocarbon C 10 H 13 (CH 3 ) 2 (C 2 H 5 ), boiling at 248, which probably is 
 dimethyl-ethyl-octohydro-naphthalene (B. 28, R. 622). 
 
 By heating with mineral acids under various conditions santonin 
 is converted into diverse so-called desmo-tropo-santonins C 15 H 18 O 3 , 
 distinguished by then- optical rotatory power, and from santonin by 
 the absence of the ketone reaction and the presence of phenol reactions. 
 It is therefore assumed that there is a transformation of a ketone 
 form into a phenol form, as in the case of carvone and carvacrol (B. 31, 
 3131 ; 36, 1386, 2667). Other transformations are produced by sun- 
 light. In an acetic acid solution the two-basic so-called photo-santonic 
 acid C 15 H 22 O 5 is formed together with iso-photo-santonie acid, a 
 dioxaldehyde-carboxylic acid ; the former passes into dehydro-photo- 
 santonic acid C 15 H 20 O 4 , with loss of water, which on oxidation yields 
 
 dimethyl - phthalide - earboxylie acid CK^ C(CI *?^ r [2] }c 8 H 3 [ 5 ]COOH, and 
 
 N GOL2J J 
 
 on distillation of its Ba-salt i, 5, 2-diethyl-iso-propyl-benzol (C. 1902, 
 I. 1402). From these data the following formulae have been deduced : 
 
 CH, C(CH S )=C CH,-CH O \^ Q > CH=C(CH,)-C CH, CH O~ 
 
 CO C(CH,)=C CH, CH CH(CH,)/ ^ C(OH) : C(CH,)-C CH, CH CH(CHJ/ 
 Santonin \ Desmo-tropo-santonin 
 
 CH,.CH(CH,).C=CH CHOH * HOCH J .CH(CH,).C=CH CHOH 
 
 HOCO.CH(CH,).C=CH CHCH(CH,)COOH HOC.CH(CH,).C=CH CHCH(CH,)COOH 
 
 Photo-santonic acid Iso-photo-santonic acid. 
 
 Artemisin C 15 H 18 O 4 , from the seeds of Artemisia maritima, is a 
 lactone closely related to santonin (cp. B. 34, 3717 ; C. 1905, I. 98). 
 
 VIII. NATURAL DYES. 
 
 The important natural dyes, indigo, alizarin, and its allies, euxanthic 
 acid, gentisin, etc., have found their place in the system of organic 
 chemistry. The following are some of the natural dyes which have not 
 yet been investigated : 
 
 Brasilin C 16 H U O 5 is found in Brazil-wood and red-wood ; crystallises 
 with iJH 2 O in white, shining needles, and dissolves in alkalies with a 
 carmine-red colour on exposure to the air. Acids then precipitate 
 brasilein C 16 H 12 O 5 +H 2 O from the solution. The action of iodine 
 upon brasilin also produces this compound. It can be reconverted 
 into brasilin by reduction, best by way of its acetyl compound (B. 36, 
 3951 ; M. 25, 871). Brasilein is, therefore, related to brasilin as dyes 
 are related to leuco-bodies. Brasilin forms mono-, di-, tri-, and 
 tetra-alkyl ethers (B. 27, 524 ; R. 304 ; 29, R. 219) ; while brasilein 
 
726 ORGANIC CHEMISTRY 
 
 forms, besides the normal -di- and trialkyl ethers, tri- and tetra-alkyl 
 brasileinols, with attachment of one molecule H 2 O (C. 1908, II. 609). 
 On distillation, brasilin yields much resorcin. On conducting air 
 for some time through a strongly alkaline solution of brasilin, we 
 obtain a compound C 9 H 6 O 4 which probably has the constitution 
 C 6 H 3(OH)^|~^ since its dimethyl ether is split up by 
 sodium alcoholate into formic acid and flsetol-dimethyl ether 
 C 6 H 3 [ 5 ](OCH3){ [ [ ^ ] ^ CH2(OCH3) , a decomposition product of fisetin (B. 
 
 32, 1024). Oxidation of trimethyl-brasilin C 16 H 10 O(OH)(OCH 3 ) 3 , m.p. 
 140, with MnO 4 K, on the other hand, produces various acids, among 
 which may be mentioned 5-methoxy-phenoxy-aeeto-2-carboxylic aeid 
 (CH 3 0)C 6 H 3 <(. >H , 4, 5-dimethoxy-phenyl-aeeto-2-earboxylie acid 
 
 (CH 3 o) 2 c 6 H 2 <^ 2 2H , and m-hemipinic acid (CH 3 O) 2 C 6 H 2 (COOH) 2 , 
 also brasilic acid ( CH 3O)C 6 H 3 <^~|^ H) CH2COOH and brasilinie acid 
 
 (CH 3 0)C 6 H 3 <( CO ^/H^H.J.CO.H- 
 
 This last acid is also formed by the condensation of m-hemipinic 
 anhydride with m-methoxy-phenoxy-acetic ester by means of A1C1 3 . 
 In a similar manner, the anhydro-brasilic acid C 12 H 10 O 5 obtained from 
 brasilic acid by dehydration has been prepared synthetically (C. 1908, 
 I. 1698). On oxidising trimethyl-brasilin with chromic acid, we obtain 
 a ketone, trimethyl-brasilone C 19 H 18 O 6 , which is converted by HNO 3 
 into nitro-hydroxy-dihydro-trimethyl-brasilone C 19 H 19 O 7 (NO 2 ). This 
 can be split up by alkalies into methoxy-salicylic acid (CH 3 O)C 6 H 3 
 (OH)COOH and nitro-homo-veratrol NO 2 C 6 H 2 (CH 3 )(OCH 3 ) 2 . The 
 trimethyl-brasilone easily passes into trimethyl-dehydro-brasilone 
 C 19 H 16 O 5 , with loss of H 2 O, and this behaves precisely like a derivative 
 of j8-naphthol. With diazonium solutions it couples up to azo-dyes ; 
 with HNO 3 it forms a nitro-compound, from which, by successive 
 reduction and oxidation, an o-quinone corresponding to j8-naphtho- 
 quinone is obtained, known as trimethoxy-a-brasane-quinone C 19 H 14 O 6 
 (C. 1909, I. 1569). By treatment with HI and with concentrated 
 H 2 SO 4 , trimethyl-brasilone is isomerised, and appears to pass into 
 derivatives of j3j3-phenylene-naphthylene oxide (brasane) (C. 1902, II. 
 746 ; 35, 1609 ; 36, 2193 ; 37, 631 ; M. 23, 165). 
 
 Hsematoxylin C 16 H 14 O 6 +3H 2 O is* the colouring-matter of logwood 
 (Hcemato%ylon campechianum) , is very soluble in water and alcohol, 
 and crystallises in yellowish prisms having a sweet taste. It dissolves 
 in alkalies with a violet-blue colour. The importance of logwood lies 
 in the production of bluish-black shades by means of iron and chrom- 
 ium. Distillation, or fusion with potash, produces pyrogallic acid from 
 haematoxylin (B. 36, 1561). When distilled or fused with potassium 
 hydroxide, pyrogallic acid and resorcinol result from it. If the am- 
 monium hydroxide solution be allowed to stand exposed to the air, 
 there results haematem-ammonia C 16 H U (NH 4 )O 6 , from which acetic 
 acid precipitates the free haematin C 16 H 12 O 6 (at 120), a reddish-brown 
 body, which has metallic lustre after drying (A. 216, 236). It yields 
 penta-ethyl- and penta-acetyl ethers. In the oxidation of tetra- 
 
NATURAL DYES 727 
 
 methyl-haematoxylin with MnO 4 K, acids are obtained analogous to 
 those from the oxidation of trimethyl-brasilin, e.g. dimethoxy-phenoxy- 
 
 acetic-o-earboxylic acid (CH 3 O)AH 2 (W^f OOH , meta-hemipinic 
 
 It. ! 2Jx^vJvJlrL 
 
 acid, and the haematoxylinicacid corresponding to brasilinic acid (above). 
 Similarly, tetramethyl-haematoxylin on oxidation with CrO 3 yields 
 tetramethyl - haematoxylone, corresponding to trimethyl - brasilone, 
 and giving quite similar decomposition products (C. 1902, II. 750 ; 
 B. 36, 2202). Haematoxylin is therefore only distinguished from 
 brasilin by the entry of an HO group into the benzene nucleus. From 
 the data hitherto obtained, Perkin has deduced the following formulae 
 for brasilin and haematoxylin : 
 
 HO [5 ]C.H, { [IJOCIITO.] }c.H l[4 , 5 ](OH) 
 
 (H0),[ 5 , 
 
 Haematoxylin . 
 
 Carthamin C 14 H 16 O 7 occurs in safflower, the blossoms of Carthamus 
 tinctorium, and is precipitated from its soda solution by acetic acid as a 
 dark-red powder, which, on drying, acquires a metallic lustre. It 
 dissolves with a beautiful red colour in alcohol and the alkalies. 
 It yields para-oxy-benzoic acid with caustic potash (A. 136, 117). 
 On boiling with dilute potash it forms p-cumaric acid and p-oxy- 
 benzaldehyde (C. 1910, II. 805). 
 
 CurcuminC 21 H 20 O 6 =[CH 3 O[3]OH[4]C 6 H 3 CH : CH.CO] 2 CH ? (?), m.p. 
 183, the dyestuff of the curcuma root of Curcuma longa and viridiflora, 
 crystallises in orange prisms and dissolves in alkalies to form reddish- 
 brown salts. It yields a dimethyl ether C 21 H 18 O 4 (OCH 3 ) 2 , m.p. 137, and 
 a diacetyl compound C 21 H 18 O 6 (C 2 H 3 O) 2 (C. 1911, 1. 652) . With hydroxyl- 
 amine we obtain, according to conditions, an oxime C 21 H 21 O 6 N, m.p. 
 162, or an isoxazol derivative C 21 H 19 O 5 N, m.p. 173. On heating 
 with potash it forms ferulic acid (B. 43, 2163). 
 
 Lichen dyes (/. pr. Ch. 2, 58, 465 ; A. 306, 282 ; 310, 230), compare 
 orseille, litmus, vulpinic acid. Of the numerous substances contained 
 in lichens,usnie acid C 18 H 16 O 7 , occurring in usnea and many other species, 
 has been studied in detail. The acid is optically active, and is found 
 naturally in the antipodic forms [a] D =;;49*5 , m.p. 203, and in the 
 racemic form, m.p. 192. It forms an oxime, an oxime anhydride, and 
 a semi-carbazone, and is therefore probably a ketonic acid. 
 
 On oxidation it is completely burnt to CO 2 , oxalic acid, and acetic 
 acid ; it therefore contains no aromatic nucleus ; by gentle oxidation 
 with Mn0 4 K the di-basic usnonic acid is obtained, C 18 H 16 O 3 . On 
 heating with alcohols to 150, usnic acid splits off CO 2 , takes up H 2 O, 
 and forms dibasic decarbo-usnic acid C 17 H 18 O 6 . For its constitutional 
 formula, see A. 310, 281 ; 324, 139. 
 
 Carminic acid C 11 H 12 O 7 is found in cochineal, from Coccus cacti 
 coccinelliferi, an insect peculiar to different cactus varieties. It is a 
 purple-red mass, dissolving readily in water and alcohol, which forms 
 red salts with the alkalies. Cochineal is applied in wool-dyeing for the 
 production of scarlet-red colours. This application has diminished 
 
728 ORGANIC CHEMISTRY 
 
 very greatly since the discovery of the red azo-dyes, like Bieberich 
 scarlet and others. The constitution of carminic acid is not yet fully 
 elucidated (B. 42, 1611). Potassium permanganate oxidises it to a 
 methyl-trioxy-a-naphtho-quinone-carboxylie acid C 12 H 17 O 7 , which, in its 
 behaviour, closely resembles iso-naphthazarin, and is therefore called 
 carminazarin. On oxidation with HNO 3 it yields a tetraketone, 
 carminazarin-quinone C 12 H 6 O 7 +2H 2 O, and in alkaline solution it is 
 converted by atmospheric oxygen into a cresotin-glyoxyl-dicar- 
 boxylic acid C n H 8 O 8 +2H 2 O, which, on heating with concentrated 
 H 2 SO 4 , decomposes into CO and the so-called eoehinelic acid C ;0 H 8 7 . 
 This acid, first obtained by the direct oxidation of carminic acid with 
 potassium persulphate, is probably an m-cresol-4, 5, 6-tricarboxylic 
 acid, since, on heating with water, it yields oxy-uvitinic acid (a-coccinic 
 acid), and I, 3, 5-cresotinic acid, and on heating alone, oxy-methyl-o- 
 phthalic acid (B. 30, 1731). By boiling with HNO 3 , carminic acid is 
 converted into nitro-coceie acid or symmetrical trinitro-cresotinic 
 acid. The following formulae illustrate this demolition of carminic 
 acid : 
 
 NO 2 HOjC O HO,C O HO 2 C CO 2 H CO 2 H 
 
 2 j , 2 2 2 
 
 Nitro-coccic acid Carminic acid Carminazarin Cresotin-glyoxyl- Cochenelic acid. 
 
 dicarboxyHc acid 
 
 The action of bromine upon carminic acid takes place in several 
 stages. A dibromo-hydro-bromide C 22 H 20 Br 2 O 13 .HBr is first formed. 
 This, on heating, easily splits off HBr and CO 2 , and passes into 
 decarboxy-dibromo-carminic acid C 21 H 20 Br 2 O 11 . By strong action of 
 bromine, several so-called bromo-carmines are formed : a-bromo- 
 
 carmine, a derivative of diketo-hydrindene HO(CH 3 )C 6 Br 2 / co \CBr 2 , 
 
 which, on heating with soda solution, decomposes into bromoform and 
 dibromoxy-methyl-phthalic acid, and /3-bromo-carmine C 11 H 6 Br 3 O 4 , 
 probably a naphtho-quinone derivative (B. 43, 1363). On methylating 
 carminic acid we obtain, according to the conditions, various methyl 
 derivatives, including carminic acid hexamethyl ether C 22 H 16 (CH 3 ) 6 O 13 
 (B. 42, 1922). Closely related to carminic acid is : 
 
 Kermessic acid C 18 H 12 O 9 , red needles, m.p. 250 with decomposition, 
 from the insect Lecanium Ilicis. Oxidation with HNO 3 gives nitro- 
 coccic acid in this case also. Its dimethyl ether yields, with MnO 4 K, 
 methyl-cochenilic methyl ester, as well as the dimethyl ether of 
 cresotin-glyoxyl-dicarboxylic acid (B. 43, 1387). Compare also the 
 similarly constituted laccainic acid C 16 H 12 O 8 (B. 29, 1285). 
 
INDEX 
 
 SUBSTANCES should also be sought in the more general paragraphs of the 
 various sections and derivatives, also under the various compounds. 
 
 ABIETIC Acid, 548 
 Acenaphthene, 50, 682 
 Acenaphthene-quinone, 682 
 Acenaphthenone, 682 
 Acetamido-azo-benzol, 144 
 Acetamido-cinnamic Acid, 422 
 
 Anhydride, 422 
 
 Acetanilide, 95 
 
 AcetanthranUido-acetic Acid, 308 
 Acetenyl-benzene, 407 
 Acetiodoso-benzoic Acid, 298 
 Aceto-acetic Anilide, 98 
 Aceto-acetic-ester phenyl-hydrazone, 159 
 Aceto-benzoic Acid, 353 
 
 Anhydride, 279 
 
 Aceto-benzoyl-benzoic Acid, 575 
 Aceto-chloramide, 100 
 Aceto-isatinic Acid, 389 
 Aceto-naphthone, 677 
 Aceto-oxindol, 310 
 Aceto-phenone, 266 
 Aceto-phenone-acetone, 375 
 Aceto-phenone Alcohol, 371 
 
 Ammonia, 267 
 
 Aceto-phenone-anilide, 372 
 Aceto-phenone-carboxylic Acid, 353 
 Aceto-phenone Oxime, 267 
 Aceto-phenyl-hydrazide, 157 
 Aceto-phenyl-imido-methyl-ether, 95 
 Aceto-phthal-aldehydic Acid, 351 
 Aceto-piperone, 326 
 Aceto-pyro-catechol, 326 
 Aceto-vanillon, 326 
 Aceto-veratron, 326 
 Acetone, 42 
 
 Acetone-diphthalide, 640 
 Acetone-oxalic Ester, 43 
 Acetonyl-phthalide, 401 
 Acetoxy-phenyl-pyro-racemic Nitrile, 394 
 Acetoxy-phthalide, 351 
 Acetyl-aceto-phenone, 375 
 Acetyl-amidrazone, 164 
 Acetyl-anisol, 326 
 Acetyl-anthranile, 303 
 Acetyl-anthranilic Acid, 302 
 Acetyl-aurins, 593 
 Acetyl-benzenyl-amidoxime, 296 
 Acetyl-benzisoxazolone, 301 
 Acetyl-benzol, 266 
 Acetyl-benzoyl Oxime, 257 
 Acetyl-carbanilide, 100 
 Acetyl-cumarin, 438 
 
 Acetyl-cyclo-hexane-carboxylic Ester, 476 
 Acetyl-cyclo-hexanone, 468 
 Acetyl-cyclopentanone, 19 
 Acetyl-A x -cyclopentene, 19 
 Acetyl-dioxindol, 378 
 Acetyl-diphenyl-thio-urea, 107 
 Acetyl-diphenyl-urea, 107 
 Acetyl-hexanitro-diphenyl-amine, 112 
 Acetyl-isatin, 389 
 
 Acetyl-methyl-phenyl-triazene, 136 
 Acetyl-opianic Acid, 352 
 Acetyl-phenyl-acetylene, 417 
 
 Acetyl-phenyl-hydroxylamine, 78 
 Acetyl-phenyl-isindazol, 571 
 Acetyl-phenyl-urea, 100 
 Acetyl-propionyl, 43 
 Acetyl-salicylic Acid, 330 
 Acetyl-salicyl Chloride, 331 
 Acetyl-thio-phenol, 327 
 Acetyl-trimethylene, 8 
 Acetyl-trimethylene-carboxylic Ester, 9 
 Acetylene, 42 
 Acetylene-anisol, 413 
 Acetylene Benzenes, 407 
 Acetylene-benzol, 30 
 Acetylene-bis-thio-salicylic Acid, 332 
 Acetylene-phenetol, 413 
 Acid Fuchsine, 587 
 Acid Green, 584 
 Yellow, 179 
 Acidum cinnamylicum, 419 
 Acidyl Anthraniles, 308 
 Acidyl-phenyl-hydrazides, 164 
 Acridone, 308, 332, 571 
 Adipin-ketone, 17 
 Adipinic Acid, 457 
 Adrenah'n, 370 
 /Esculetin, 431 
 /Esculin, 721 
 
 jEsculus hippocastanum, 721 
 Alcohol-carboxylic Acids, 347 
 Alcoholic Hydroxyls, 105 
 Aldehyde Acids, 350 
 
 Alcohols, 345 
 
 Green, 588 
 
 Aldehydins, 116 
 Aldehydo-benzoic Acid, 353 
 Aldehydo-dicarboxylic Acids, 364 
 Aldehydrazones, 152 
 Aldonaniline, 91 
 Aldoximes, 254 
 Ah'phatic Compounds, 2 
 
 Diazo-compounds, 6 
 
 AJizarin, 702, 714, 725 
 
 Blue, 715 
 
 Alizarin-bordeaux, 717 
 Alizarin-dimethyl Ether, 715 
 Alizarin Saphirol, 713 
 Alizarin-sulphonic Acid, 715 
 Alizarine, 212 
 Alkali Blue, 589 
 Alkaline Diazotates, 124 
 Alkyl-aryl-sulphones, 182 
 Alkyl-benzoic Acids, 274 
 Alkyl-benzols, 51 
 
 Halogen Derivatives of, 64 
 
 Nitro-halogen Derivatives of, 74 
 
 Nitro-products of, 73 
 
 Alkyl-cumarins, 428 
 Alkyl-phenyl-hydrazin, 152 
 Alkyl-phenyl-ureas, 99 
 Alkyl-terephthalic Acids, 362 
 Alkylamines, 156 
 Alkylated diphenyls, 550 
 
 Phenanthrenes, 689 
 
 Phenyl-hydrazins, 152 
 
 729 
 
730 
 
 INDEX 
 
 Alkylated Rosanilins, 588 
 Alkylic Anthracenes, 703 
 
 Para-rosanilins, 587 
 
 Rhodamins, 601 
 
 Alkylidene-dianilines, 90 
 Alkylidene-monoanilines, 90 
 Allo-chryso-keto-carboxylic Acid, 680 
 Allo-chryso-ketone-carboxylic Acid, 701 
 AUo-cinnamic Acid, 420 
 
 Dibromide, 386 
 
 Bichloride, 385 
 
 Allophanic Acid, 100 
 Allyl-aceto-phenone,4i 7 
 Allyl-benzol, 406 
 
 Allyl-benzoyl-acetic Ester, 393, 438 
 Allyl-cyclo-hexane, 449 
 AUyl-phenol, 409 
 Allylene, 42, 51 
 Almond Acid, 376 
 Aloetic Acid, 724 
 Aloin, 724 
 
 Alphyl-cyanides, 286 
 Alphyl-Hydroxylamines, 77 
 Alphyl-nitroso-hydroxylamines, 79 
 Aluminium phenate, 186 
 Alyl-naphthalin, 658 
 Amaric Acid, 639 
 Amarine, 257 
 Amber, 549 
 Amide Iodides, 286 
 Amido-aceto-phenones, 269, 372 
 Amido-alizarin, 715 
 Amido-anilic Acid, 230 
 Amido-azo-benzol, 144 
 Amido-azo-benzol-sulphonic Acids, 178 
 Amido-azo-compounds, 142 
 Amido-azo-naphthalene, 662, 663 
 Amido-azo-toluol, 144 
 Amido-benzal-acetone, 416 
 Amido-benzaldehydes, 263 
 Amido-benzene, 29 
 Amido-benzo-hydrol, 566 
 Amido-benzo-phenones, 570, 571 
 Amido-benzoic Acid, 309 
 Amido-benzol, 79 
 Amido-benzol-sulphonic Acids, 177 
 Amido-benzoyl-carbinol, 372 
 Amido-benzyl Alcohol, 250 
 Amido-benzyl-amine, 250, 252 
 Amido-benzyl-aniline, 250 
 Amido-benzyl Chloride, 251 
 Amido-benzyl-phenols, 564 
 Amido-butyro-phenone, 373 
 Amido-campholene, 538 
 Amido-camphor, 534 
 Amido-camphor-chlorohydrate, 534 
 Amido-chloro-styrol, 406 
 Amido-cinnarnic Acids, 422, 423 
 Amido-cyclo-hexane, 455 
 Amido-diazo-benzol-imide, 138 
 Amido-dimethyl-aniline, 115 
 Amido-diphenyls, 552 
 Amido-diphenyl-amine, 116, 147 
 Amido-diphenyl-aniline : 114 
 Amido-diphenyl-guanidin, 104 
 Amido-diphenylene-ketone, 699 
 Amido-diphenyl-methanes, 564 
 Amido-diphenyl Sulphide, 180 
 Amido-ditolyls, 552 
 Amido-ethyl-benzol, 87 
 Amido-fluorene, 697, 700 
 Amido-guanidone, 235 
 Amido-hemi-pinic Acid, 359 
 Amido-hydrindene, 648 
 Amido-hydro-carbo-styrile, 311 
 Amido-hydro-cinnamic Acid, 383 
 Amido-iso-propyl-benzol, 87 
 Amido-mandelic Acid, 378 
 Amido-methyl-benzols, 85 
 Amido-naphthoic Acid, 678 
 Amido-naphthols, 667 
 Amido-naphthol-sulphonic Acids, 670 
 Amido-nitro-fluorene, 697 
 Amido-octyl-benzol, 87 
 Amido-oxindol, 310 
 Amido-oxy-anthraquinones, 715 
 
 Amido-oxy-biphenyls, 557 
 Amido-oxy-diphenyl, 557 
 Amido-oxy-naphthoic Acid, 679 
 Amido-oxy-phenanthrene, 690 
 Amido-oxy-triphenyl-carbinols, 592 
 Amido-pentamethyl-benzol, 37 
 Amido-phenanthrene, 690 
 Amido-phenanthrene-quinones, 692 
 Amido-phenols, 117, 199 
 Amido-phenyl-acetylene, 407 
 Amido-phenyl-arsinic Acid, 170 
 
 Oxide, 170 
 
 Amido-phenyl-fatty Acids, 310 
 Amido-phenyl-glyceric Acid, 385 
 Amido-phenyl-guanidin, 162 
 Amido-phenyl-methyl-hydrazin, 152 
 Amido-phenyl-propiolic Acid, 433 
 Amido-phenyl Sulphides, 210 
 Amido-phenyl-urethane, 114 
 Amido-phthalic Acids, 359 
 Amido-phthalide, 351 
 Amido-polymethyl-benzols, 86 
 Amido-propio-phenone, 372, 373 
 Amido-propyl -benzol, 87 
 Amido-quinone Imine, 234 
 Amido-quinones, 229 
 Amido-sah'cylic Acid, 333 
 Amido-saligenin, 316 
 Amido-styrol, 406 
 
 Amido-suberane-carboxylic Acid, 25 
 Amido-terebentene, 519 
 Amido-tert. -butyl-benzol, 82, 87 
 Amido-tetramethylene, n 
 Amido-thio-pbenols, 96, 117, 209 
 Amido-triphenyl-amine, 116 
 Amido-triphenyl-carbinols, 582 
 Amido-valero-phenone, 373 
 Amidol, 202 
 Amidoximes, 286, 392 
 
 Hetero-ring Formations of, 296 
 
 Amidrazones, 142, 157, 163, 291 
 Amino-anthraquinone, 711 
 Amino-aurin, 594 
 Amino-cyclo-heptene, 24 
 Amino-trimethylene, 7 
 Amino-triphenyl-carbinol, 582 
 Amino-triphenyl-methane, 578 
 Amygdalin, 225, 255, 723 
 Amyl-anthracenes, 704 
 Andropogon nardus, 522 
 Anemones, 724 
 Anemonin, 724 
 Anethol, 334, 363, 410 
 
 Dibromide, 369 
 
 Nitrite, 410 
 
 Anethol-nitroso-chloride, 410 
 Anethol-pseudo-nitrosite, 410 
 Anethum fceniculum, 410 
 
 graveolens, 412 
 
 Angra.cum fragrans, 427 
 Anhydro-acetonebenzile, 17 
 Anhydro-bases, 667 
 Anhydro-benzile-laevulinic Acid, 17 
 Anhydro-brasilic Acid, 726 
 Anhydro-geraniol, 487 
 Anile-aceto-acetic Ester, 98 
 Anile-pyro-racemic Acid, 98 
 Anile-uvitoninic Acid, 98 
 Anilic Acid, 356 
 Anilido-acetic Acid, 97 
 Anilido-azo-benzol, 144 
 Anilido-butylidene-aniline, 91 
 Anilido-butyric Acid, 98 
 Anilido-crotonic Ester, 99 
 Anilido-malonic Acid, 108 
 Anilido-phenyl, 100 
 Anilido-phenyl-acetic nitrile, 379 
 Anilido-phosphoric Dichloride, 93 
 Anih'do-propionic Acid, 98 
 
 Ester, 98 
 
 Anilido-pyrrols, 155 
 Aniline, 69, 79, 83 
 
 Black, 237 
 
 Blue, 91, 92, 589 
 
 Chlorohydrate, 82 
 
 Salts, 84 
 
INDEX 
 
 Aiiilino-cyclo-pentene, 16 
 Anilino-diacetic Acid, 98 
 Anilino-guanidin, 162 
 Anilino-methylene-acetic Ester, 96 
 Anilino-methylene-malonic Ester, 96 
 Anilo-biguanide, 162 
 Anilo-succimide, 163 
 Anis-acetone, 327 
 Anisal Chloride, 323 
 Anisaldoxime, 322 
 Anisic Acid, 334 
 
 Aldehyde, 322 
 
 Anisile, 618 
 Anisilic Acid, 607 
 Anisol, 190 
 
 Anisol-diazonium Cyanide, 125 
 Anisolines, 602 
 Anisyl Alcohol, 316 
 Annidalin, 188 
 Anol, 410 
 
 Anthra-chrysone, 717 
 Anthra-cumarin, 707, 708 
 Anthra-diamine, 705 
 Anthra-hydroquinone, 706, 708 
 Anthra-phenone, 708 
 Anthra-purpurin, 717 
 Anthra-pyrimidin, 712 
 Anthra-pyrimidone, 712 
 Anthracene, 27, 50, 703 
 
 Group, 701 
 
 Anthracene-carboxylic Acids, 708 
 Anthracene Dihydride, 708 
 Anthracene-monosulphonic Acid, 705 
 Anthracene-sulphonic Acid, 705 
 Anthraflavic Acid, 716 
 Anthragallol, 717 
 Anthramine, 705 
 Anthranile, 73, 302 
 
 Sulpho-acid, 73 
 
 AnthranUic Acid, 72, 301 
 
 Dimolecular Anhydrides of, 304 
 
 Betain, 306 
 
 Formalide, 307 
 
 Nitrile, 302 
 
 Anthranilido-acetic Acid, 307 
 
 Anthranilido-diacetic Acid, 307 
 
 Anthranilido-diaceto-nitrile, 307 
 
 Anthranol-ethyl Ether, 706 
 
 Anthranoyl-anthranilic Acid, 304 
 
 Anthraquinone, 705, 709 
 
 Anthraquinone-carboxylic Acids, 717 
 
 Anthraquinone-oxime, 705 
 
 Anthraquinone-sulphonic Acids, 712 
 
 Anthrarobin, 707 
 
 Anthrarufin, 706, 716 
 
 Anthrol, 705 
 
 Anthrone, 706, 709 
 
 Anthroxan-aldehyde, 374 
 
 Anthroxanic Acid, 303, 389 
 
 Antifebrin, 95 
 
 Antipyrin, 149 
 
 Apinol, 412 
 
 Apiol, 412 
 
 Apionol, 223 
 
 Apo-camphoric Acid, 525, 544 
 
 Arbutin, 720 
 
 Arbutus uva ursi, 720 
 
 Archil, 217 
 
 Aristol, 188 
 
 Armstrong, 41 
 
 Arnica montana, 219 
 
 Aromatic Acid Haloids, 278 
 
 Acids, Imido-ethers of the 288 
 
 Thiamides of the, 288 
 
 Amido-monocarboxylic Acids, 301 
 
 Carboxylic Acids, Imido-thio-ethers of the, 
 
 289 
 
 Compounds, 27 
 
 Di-aldehydes, 346 
 
 Dicarboxylic Acids, 363 
 
 Di-halogen Toluols, 66 
 
 Hexacarboxylic Acid, 366 
 
 Monaldehydes, 252 
 
 Monocarboxylic Acids, 269 
 
 Formazyl Derivatives of the, 292 
 
 Substituted, 297 
 
 Aromatic Monoketones, 264 
 
 o-Amido-ketones, 269 
 
 Oxymono-aldehydes, 321 
 
 Pentacarboxylic Acid, 366 
 
 Polyalcohols, 367 
 
 Substances, 2 
 
 Tetracarboxylic Acids, 365 
 
 Thionylamines, 92 
 
 Arsanilic Acid, 170 
 Arsen-anilido-dibromide, 93 
 Arsen-anilido-dichloride, 93 
 Arsen-anih' do-dimethyl-ether, 93 
 Arsen-dianilido-monochloride, 93 
 Arseno-benzol, 170 
 Artemisia Barrelieri, 510 
 
 etna, 499 
 
 mantima, 725 
 
 Artemisin, 725 
 Aryl-acetaldoximes, 405 
 Aryl-hydroxylamines, 77 
 Aryl-magnesium Haloids, 171 
 Asarone, 325, 412 
 Asarum ari folium, 411 
 
 europ&um, 411 
 
 Asaryl-aldehyde, 325 
 Aseptol, 207 
 Asperula, 428 
 
 Essence, 428 
 
 Asperula odorata, 428 
 
 Aspidium filix-mas, 222 
 
 Atro-glyceric Acid, 384 
 
 Atro-lactinic Acid, 379 
 
 Atropic Acid, 425 
 
 Atroxindpl, 311 
 
 a-Truxillic Acid, 13 
 
 Auramin, 572 
 
 Aurins, 1 86, 590, 593 
 
 Azelaol, 26 
 
 Azelaone, 26 
 
 Azi-benzile, 616 
 
 Azimides, 116 
 
 Azimido-benzoic Acid, 310 
 
 Azo-benzide, 141 
 
 Azo-benzoic Acids, 311 
 
 Azo-benzol, 69, 140, 141 
 
 Azo-benzol-m-monocarboxylic Acid, 312 
 
 Azo-benzol-phenyl-hydrazin-sulphonic Acid, 157 
 
 Azo-camphenone, 533 
 
 Azo-camphor, 534 
 
 Azo-cpmpounds, 140 
 
 Azo-dibenzoyl, 283 
 
 Azo-di-carbon-anUide, 101 
 
 Azo-naphthols, 668 
 
 Azo-opianic Acid, 359 
 
 Azo-phenols, 204 
 
 Azo-toluols, 142 
 
 Azo-trimethyl-benzols, 142 
 
 Azo- violet, 457 
 
 Azoxy-aniline, 140 
 
 Azoxy-benzaldehydes, 262 
 
 Azoxy-benzide, 139 
 
 Azoxy-benzoic Acids, 311 
 
 Azoxy-benzol, 69, 139 
 
 Azoxy-benzyl Alcohol, 250 
 
 Azoxy-compounds, 139 
 
 Azoxy-phenols, 203 
 
 Azoxy-toluol, 140 
 
 Azoxylenes, 142 
 
 Azurin, 237 
 
 BAEYER, VON, 3, 41, 418, 443. 477, 485, 486, 495, 
 5i6, 599 
 
 Tension theory of, 3 
 
 Barbaloin, 717, 724 
 Benckiser, 231, 232 
 Benzal-aceto-acetic Ester, 438 
 Benzal-acetone, 416 
 Benzal-acetone-phenyl-hydrazone, 416 
 Benzal-amidp-sulphonic Acid, 260 
 Benzal-angelic lactone, 439 
 Benzal-anfline, 257 
 Benzal-azin, 258 
 Benzal-barbituric Acid, 439 
 Benzal-benzamidine, 290 
 Benzal-benzoyl-hydrazin, 284 
 Benzal-benzyl-acetone, 638 
 
732 
 
 INDEX 
 
 Benzal-bis-acetyl-acetone, 376 
 Benzal Bromide, 257 
 Benzal Chloride, 30, 64, 257 
 Benzal-diphenyl-dihydro-tetrazone, 167 
 Benzal-diphenyl-maleide, 623 
 Benzal-divanillin, 594 
 Benzal-ethyl-amine, 257 
 Benzal-glutaric Acid, 441 
 Benzal-hydrazin, 258 
 Benzal-la?voxime, 438 
 Benzal-laevulinic Acid, 438, 439 
 Benzal-malonic Acid, 439 
 Benzal-mesityl Oxide, 418 
 Benzal-nitro-aceto-phenone, 628 
 Benzal-phenyl-croto-lactone, 635 
 Benzal-phenyl-glyceric Ester, 384 
 Benzal-phenyl-hydrazone, 258 
 Benzal-phthalide, 620 
 Benzal-pinacolin, 417 
 Benzaldehyde, 30, 64, 255 
 
 Derivatives of, 256 
 
 Benzaldehydes, Haloid, 260 
 
 Substituted, 260 
 
 Benzaldehyde, Sulphur Derivatives of, 257 
 Benzaldehyde-potassium Bisulphite, 257 
 Benzaldoximes, 253, 258 
 Benzaldoxime Peroxide, 260 
 Benzamarone, 639 
 Benzamide, 281 
 
 Bromide, 287 
 
 Chloride, 287 
 
 Haloids, 297 
 
 Iodide, 287 
 
 Benzamidine, 289 
 Benzamidine-diazo-benzol, 290 
 Benzamidine-urethane, 290 
 Benzanilide, 281 
 
 Chloro-iodide, 287 
 
 Benzanilide-imido-chloride, 287 
 Benzanthrones, 718 
 Benzantialdoxime, 259 
 
 Acetate, 260 
 
 Benzaurin, 591 
 Benzazimide, 311 
 Benzazurin, 557 
 Benze'ins, 590, 591 
 Benzene, 46, 49 
 
 Azo-sulphonic Acid, 127 
 
 Carbohydrates, 49 
 
 Derivatives, 27 
 
 General Survey of, 29 
 
 Isomerism of, 31 
 
 Benzene-diazo-acetanilide, 135 
 Benzene-diazo-carboxyl-amide, 128 
 Benzene-diazo-sulphones, 127 
 Benzene, Halogen Substitution Products of, 60 
 
 Hexabromide, 447 
 
 Hexachloride, 447 
 
 Hydrocarbons, Nitrogen Derivatives of, 67 
 
 Nitroso-Derivatives of, 75 
 
 Nucleus, Constitution of, 40 
 
 Oxy-quinones, 230 
 
 Poly-substitution Products, Isomerism of, 39 
 
 Ring Formations, 42 
 
 Ring Splittings, 45 
 
 Substitution Produc 
 
 for, 34 
 
 Benzenyl-amidine, 289 
 Benzenyl-amidoxime, 296 
 Benzenyl Compounds, 287 
 Benzenyl-diphenyl-diureide, 290 
 Benzenyl-ethoxime Bromide, 294 
 Benzenyl-ethyl Ether, 297 
 Benzenyl -hydrazidin, 291 
 Benzenyl-hydrazidoxime, 296 
 Benzenyl-hydroxylamine-acetic Acid, 294 
 Benzenyl-methoxime Chloride, 294 
 Benzenyl-nitrazone, 291 
 Benzenyl-nitrosazone, 291 
 Benzenyl-oxy-tetrazotic Acid, 290 
 Benzenyl-tetrazotic Acid, 291 
 Benzenyl Trichloride, 297 
 Benzidin, 147, 553 
 
 Dyes, 178, 555 
 
 Homologues, 554 
 
 Sulphate, 554 
 
 lucts, Principles of Location 
 
 Benzidin-sulphonic Acids, 556 
 Benzidin Transposition, 147 
 Benzile, 616 
 
 Benzile-carbpxylic Acid, 620 
 Benzile-dioxime Diacetates, 617 
 Benzile-dioximes, 617 
 Benzile-osazone, 617 
 Benzile-semi-carbazone, 616 
 Benzilic Acid, 607 
 Benzimido-ethyl Ether, 288 
 Benzimido-methyl Ether, 288 
 Benzimido-thio-ethyl Ether, 289 
 Benzimido-thio-phenyl Ether, 289 
 Benzisoxazolone, 301 
 Benzol-azo-meso-anthramine, 705 
 Benzo-cyclo-heptadienone, 642 
 Benzo-cyclo-heptadione, 642 
 Benzo-cyclo-heptane, 642 
 Benzo-cyclo-heptanone, 642 
 Benzo-cyclo-heptene, 642 
 Benzo-diazo-thin, 161 
 Benzo-dioxy-anthracenes, 706 
 Benzo-hydrols, 565 
 Benzo-hydrol-carboxylic Acids, 574 
 Benzo-hydroxamic Acid, 293 
 
 Haloids of, 294 
 
 Benzo-hydroxamoxime, 297 
 Benzo-hydroximic Acid Alkyl Ethers, 293 
 
 Chloride, 294 
 
 Benzo-hydryl-amine, 565 
 Benzo-hydryl-hydrazin, 566 
 Benzo-nitrile, 97, 259, 286 
 
 Oxide, 295 
 
 Benzo-nitrolic Acid, 294 
 Benzo-nitrosolic Acid, 295 
 Benzo-norcaradiene-carboxylic Ester, 641 
 Benzo-phenol, 185 
 Benzo-phenones, 567, 603 
 Benzo-phenone Bromide, 568 
 
 Chloride, 568 
 
 Benzo-phenone-dicarboxylic dilactone, 575 
 Benzo-phenone Hexachloride, 570 
 
 Homologues, 568 
 
 Benzo-phenone-hydrazone, 569 
 Benzo-phenonoxime, 569 
 Benzo-phenyl-amido-ethyl Xanthide, 289 
 Benzo-pinacolin, 625 
 
 Alcohol, 625 
 
 Benzo-pinacone, 625 
 Benzo-quinone, 225, 226 
 Benzo-quinone-bis-diphenyl-methane, 602 
 Benzo-sulpho-hydroxamic Acid, 175 
 Benzo-sulphone-anthranilic Acid, 302 
 Benzo-tetronic Acid, 437 
 Benzo-thiazols, 209 
 Benzo-trichloride, 64, 297 
 Benzo-trifluoride, 297 
 Benzoic Acid, 31, 64, 273 
 
 Trichloride, 297 
 
 Anhydride, 279 
 
 Benzoic-arsenic Anhydride, 279 
 Benzoic-boric Anhydride, 279 
 Benzoic-carbonic Anhydride, 280 
 Benzoic Sulphinide, 314 
 Benzoic-thionyl-hydrazone, 312 
 Benzoin, 615 
 
 Benzoln-anile-anilide, 616 
 Benzoin-anilide, 616 
 Benzoin Hydrazone, 616 
 
 Yellow, 708 
 
 Benzol, 49 
 
 Benzol-azo-aceto-acetic Ester, 154 
 Benzol-azo-aldoximes, 142 
 Benzol-azo-anthranol, 706 
 Benzol-azo-benzyl Alcohol, 251 
 Benzol-azo-cyanamide, 136 
 Benzol-azo-diphenyl-amine, 144 
 Benzol-azo-ethane, 142 
 Benzol-azo-methane, 140, 142, 152 
 Benzol-azo-naphthalene, 662 
 Benzol-azo-nitronic Acids, 142 
 Benzol-azo-phenyl-cyanamide, 144 
 Benzol-azo-phenyl-glycin, 144 
 Benzol-azo-sah'cylic Acid, 333 
 Benzol-carboxylic Acid, 31 
 Benzol-diazo-anilide, 135 
 
INDEX 
 
 733 
 
 Benzol-diazo-carboxylic Acids, 142 
 
 Benzol-diazo-oxy-amido-methane, 137 
 
 Benzol-diazonium-chloride, 125 
 
 Benzol-diazonium fluorides, 125 
 
 Benzol-dicarboxylic Acid, 31 
 
 Benzol-disulphinic Acid, 181 
 
 Benzol-disulphonic Acids, 176 
 
 Benzol -disulphoxide, 181 
 
 Benzol-hexacarboxylic Acid, 43 
 
 Benzol -iodp-fluoride, 61 
 
 Benzol-o-dicarboxylic Acid, 37 
 
 Benzol-phenol-phthalide, 596 
 
 Benzol-phthalin, 594 
 
 Benzol-seleninic Acid, 181 
 
 Anhydride, 181 
 
 Benzol-seleno-acid, 176 
 
 Benzol-sulphamide, 174 
 
 Benzol-sulphinic Acid, 180 
 
 Anhydride, 180 
 
 Chloride, 180 
 
 Benzol-sulpho-acid, 29 
 
 Benzol-sulpho-diazo-benzol-amide, 1 75 
 
 Benzol-sulpho-dichlor-amide, 174 
 
 Benzol-sulpho-isocyanate, 175 
 
 Benzol-sulpho-nitramide, 174 
 
 Benzol-sulphone, 182 
 
 Benzol -sulphone-anilide, 174 
 
 Benzol-sulphone-azode, 175 
 
 Benzol-sulphone-phenyl-hydrazide, 175 
 
 Benzol-sulphonic Acid, 174, 178 
 
 Benzol -sulphono-hydrazide, 174 
 
 Benzol-sulphono-phenyl-hydroxylamine, 78 
 
 Benzol-thio-sulphonic Acid, 181 
 
 Benzol-tricarboxylic Acid, 31 
 
 Benzol-trisulphonic Acid, 176 
 
 Benzoleinic Acid, 471 
 
 Benzolene, 30 
 
 Benzoxazoles, 201 
 
 Benzoyl-acetaldehyde, 374 
 
 Benzoyl-acetic Acid, 391 
 
 Ester, 392 
 
 Benzoyl-aceto-nitrile, 392 
 
 Benzoyl-acetone, 375 
 
 Benzoyl-acetyl, 374 
 
 Benzoyl-acrylic Acid, 438 
 
 Benzoyl-alanin, 283 
 
 Benzoyl-amido-cinnamic Anhydride, 422 
 
 Benzoyl-amyl-acetylene, 417 
 
 Benzoyl-anthracene, 708 
 
 Benzoyl-anthranile, 303 
 
 Benzoyl-anthranilic Acid, 302 
 
 Benzoyl-asparaginic Acid, 283 
 
 Benzoyl-azide, 284 
 
 Benzoyl Azimide, 279 
 
 Benzoyl-benzo-hydroxamic Ester, 293 
 
 Benzoyl-benzoic Acid, 575 
 Benzoyl-benzylamine, 281 
 
 Benzoyl bromide, 279 
 Benzoyl-bromimide, 281 
 Benzoyl-butane-diol, 400 
 Benzoyl-butyl-carbinol, 373 
 Benzoyl-camphor, 536 
 Benzoyl-carbinol, 371 
 
 Acetate, 371 
 
 Chloride, 371 
 
 Benzoyl Chloride, 278 
 Benzoyl-chlorimide, 281 
 Benzoyl-crotonic Acid, 438 
 Benzoyl-cumarone, 629 
 Benzoyl Cyanide, 388 
 
 Anile, 388 
 
 Benzoyl-cyano-acetic Methyl Ester, 399 
 Benzoyl-diazo-benzol, 142 
 Benzoyl-diazo-methane, 372 
 Benzoyl-dibenzyl-methane, 630 
 Benzoyl Disulphide, 280 
 
 Fluoride, 279 
 
 Benzoyl-formaldehyde, 373 
 Benzoyl-formic Acid, 367, 387 
 Benzoyl-formoin, 635 
 Benzoyl-formoxime, 374 
 Benzoyl-glutaric Acid, 399 
 
 Ester, 399 
 
 Benzoyl-glycocoll, 282 
 Benzoyl-glycollic Acid, 278, 394 
 Benzoyl-glyoxylic Acid, 395 
 
 Benzoyl-hydrazin, 283 
 
 Benzoyl-hydrogen Peroxide, 255 
 
 Benzoyl Iodide, 279 
 
 Benzoyl-isatin, 389 
 
 Benzoyl-iso-cyanate, 282 
 
 Benzoyl-iso-succinic Ester, 399 
 
 Benzoyl-malonic Ester, 399 
 
 Benzoyl-mesitylene, 568 
 
 Benzoyl Nitrate, 279 
 
 Nitride, 279, 284 
 
 Nitrite, 279 
 
 Peroxide, 280 
 
 Benzoyl-phenyl-acetylene, 630 
 
 Benzoyl-phenyl-alanin, 381 
 
 Benzoyl-phenyl-carbinol, 615 
 
 Benzoyl-phenyl-fluorene, 698 
 
 Benzoyl-phthalic Acid, 575 
 
 Benzoyl-propio-aldehyde, 374 
 
 Benzoyl-pyro-racemic Acid, 395 
 
 Benzoyl Sulphide, 280 
 
 Benzoyl-tetramethylene, 268 
 
 Benzoyl-tricarballylic Acids, 400 
 
 Benzoyl-trimethylene, 268, 393 
 
 Benzoyl-tri-methylene-carboxylic Acid, 393 
 
 Benzoyl-xylol, 568 
 
 Benzoylated Paraflins, 267 
 
 Benzoylene-urea, 308 
 
 Benzyl Acetamide, 247 
 
 Acetate, 243 
 
 Benzyl-aceto-acetic Ester, 393 
 
 Benzyl-aceto-phenone, 628 
 
 Benzyl-aceto-succinic Ester, 399 
 
 Benzyl-alcohol, 30, 64, 241 
 
 Benzyl-amido-acetone, 373 
 
 Benzyl-amines, 245 
 
 Benzyl-aniline, 247 
 
 Benzyl-arabinoside, 243 
 
 Benzyl-azides, 248, 249 
 
 Benzyl-benzol, 563 
 
 Benzyl Bromide, 243 
 
 Carbinol, 242 
 
 Carbonimide, 247 
 
 Chloride, 30, 64, 243 
 
 Benzyl-cinnamic Acid, 631 
 
 Benzyl-crotonic Acid, 425 
 
 Aldehyde, 415 
 
 Benzyl-cyanurate, 247 
 
 Benzyl-desoxy-benzoin, 629 
 
 Benzyl-diazo-compounds, 248 
 
 Benzyl Disulphide, 244 
 Disulphoxide, 244 
 
 Benzyl-durols, 563 
 
 Benzyl-ethyl-amine, 246 
 Benzyl-glutaconic Ester, 441 
 Benzyl-hydrazins, 248 
 
 Benzyl Hydride, 255 
 Benzyl hydroxylamines, 249 
 Benzyl-hyposulphurous Acid, 244 
 Benzyl-indene, 645 
 Benzyl Iodide, 243 
 Benzyl Iso-cyanate, 247 
 Benzyl-iso-nitroso-aceto-phenone, 628 
 Benzyl-malic Acid, 398 
 Benzyl-malpnic Acid, 396 
 Benzyl-mesitylene, 563 
 Benzyl-methyl-ethyl Ketone, 268 
 Benzyl-methyl-ketone, 376 
 Benzyl-methyl-triazene, 248 
 Benzyl-mustard Oil, 248 
 Benzyl-nitramine, 248 
 Benzyl Nitrite, 243 
 Benzyl-oxalacetic Ester, 399 
 Benzyl-oxethyl-amine, 247 
 Benzyl -phenyl-acetic Acid, 621 
 Benzyl-phenyl-iso-crotonic Acid, 636 
 Benzyl-phenyl-carbinol, 613 
 Benzyl-phenyl-triazene, 249 
 Benzyl Phosphates, 243 
 Benzyl-phthalazone, 620 
 Benzyl-phthah'midine, 620 
 Benzyl-propyl Ketone, 268 
 Benzyl-pyro-racemic Acid, 391 
 Benzyl-succinic Acid, 397 
 Benzyl Sulphide, 244 
 Benzyl-sulphinic Acid, 244 
 Benzyl Sulphone, 244 
 
734 
 
 INDEX 
 
 Benzyl-sulphonic Acid, 244 
 
 Benzyl Sulphoxide, 244 
 
 Benzyl-sulphuric Acid, 243 
 
 Benzyl Sulphydrate, 244 
 
 Benzyl-tartronic Acid, 398 
 
 Benzyl-toluenes, 563 
 
 Benzyl-triazenes, 248 
 
 Benzyl-urea, 247 
 
 Benzyl-urethane, 247 
 
 Benzylidene-aceto-phenone, 628 
 
 Benzylidene-acetone, 416 
 
 Benzylidene-acetyl-phenyl-triazane, 10 
 
 Benzylidene-aniline, 257 
 
 Benzylidene-anthrone, 706 
 
 Benzylidene-benzoyl-acetic Ester, 631 
 
 Benzylidene-bis-benzoyl-acetic Ester, 640 
 
 Benzylidene-bis-desoxy-benzofn, 639 
 
 Benzylidene-campholic Acid, 537 
 
 Benzylidene-camphor, 536 
 
 Benzylidene-desoxy-benzoin, 629 
 
 Benzylidene-diaceto-phenone, 639 
 
 Benzylidene-fluorene, 696 
 
 Benzylidene-formyl-phenyl-triazane, 167 
 
 Benzylidene-hydrazin, 258 
 
 Benzylidene Imide, 257 
 
 Benzylidene-menthone, 506 
 
 Benzylidene-methyl-ethyl-ketone, 416 
 
 Benzylidene-phenoxy-acetone, 417 
 
 Benzylidene-phthalide, 620 
 
 Benzylidene-pulegone, 508 
 
 Benzylidene-thujone, 510 
 
 Bergaptene, 435 
 
 Bernthsen, 599] 
 
 Berthelot, 49 
 
 Berzelius, 226 
 
 Be tula lenta, 721 
 
 Bidesyl, 634 
 
 Bi-diphenylene-e thane, 698 
 Bi-diphenylene-ethylene, 698 
 Bieberich Scarlet, 179, 668 
 Bifluorene, 698 
 Biguanide, 162 
 Bihydroquinone, 557 
 Biphenol, 557 
 Biphenyl, 550 
 
 Biphenyl-carboxylic Acids, 559 
 Biphenyl-dicarboxylic Acids, 560, 561 
 Biphenyl-monocarboxylic Acids, 559 
 Biphenyl-sulphonic Acids, 556 
 Biphenylene-biphenyl-chloro-methane, 62 7 
 Biphenylene-phenyl-methyl, 697 
 Biphenylene sultame, 556 
 Bipyro-catechin, 557 
 Bis-acenaphthylidene, 682 
 Bis-amido-benzyl-resorcin, 576 
 Bischoff, 418 
 
 Bis-cyclopentadiene-carboxylic Acid, 20 
 Bis-diazo-benzol-diphenyl-tetrazone, 1 68 
 Bis-triazo-benzol, 138 
 Bismarck Brown, 114, 145 
 Bismuth Gallate, 341 
 
 Oxy-iodide Gallate, 341 
 
 Bismuth-triphenyl, 170 
 Bi-thio Acids, 280 
 Bi-thio-phenyl-phthalide, 355 
 Bitter-almond Oil, 255 
 Blomstrand, 123 
 Borneo Camphor, 526 
 Borneol, 526, 529 
 Bornyl-iso-valerianate, 527 
 Bornyl-xanthogenic Methyl Esters, 527 
 Bornylamine, 528 
 Bornylene, 524 
 
 Bornylene-carboxylic Acid, 535 
 Bornylone, 533 
 Bornyval, 527 
 Boutron-Chalard, 723 
 Brasanes, 672 
 Brasilic Acid, 726 
 Brasilin, 725 
 Brasilinic Acid, 726 
 Briganum hirtum, 188 
 Brom-acetanilide, 95 
 Bromaceto-phenone, 268 
 Bromanilic Acid, 230 
 Bromethenyl-phenyl Ether, 190 
 
 Bromethyl-phenyl Ether, 190 
 
 Bromindone, 647 
 
 Bromine Tribromo-phenol, 194 
 
 Bromo-aceto-phenone, 371 
 
 Bromo-alizarin, 715 
 
 Bromo-anthraquinone, 710 
 
 Bromo-benzo-phenone, 569 
 
 Bromo-benzols, 31, 61 
 
 Bromo-camphor, 532 
 
 Bromo-carmine, 728 
 
 Bromo-cinnamic Acids, 421, 422 
 
 Bromo-cumarin, 428 
 
 Bromo-diazo-benzol-imide, 138 
 
 Bromo-diazonium Silver Cyanide, 125 
 
 Bromo-diketo-hydrindene, 649 
 
 Bromo-diphenacyl, 634 
 
 Bromo-hydrin, 369 
 
 Bromo-iodo-benzols, 61 
 
 Bromo-methylene-phthah'de, 434 
 
 Bromo-naphthalenes, 659 
 
 Bromo-nitro-benzols, 35, 76 
 
 Bromo-nitro-camphane, 532 
 
 Bromo-nitro-camphor, 532 
 
 Bromo-nitroso-acetanilide, 120 
 
 Bromo-pentamethyl-benzol, 66 
 
 Bromo-phenanthrene, 689 
 
 Bromo-phenyl-hydrazin, 150 
 
 Bromo-phthalide, 351 
 Bromo-piperonal, 325 
 Bromo-salicylic Acid, 333 
 Bromo-styrol, 404, 405 
 Bromo-suberane-carboxylic Acid, 24 
 Bromo-toluol, 65 
 Bromo-xylol, 66 
 Bromyl-phthalimide, 357 
 Brown, Crum, 74 
 Briihl, 40 
 
 Bucco-camphor, 508 
 Butane-tetracarboxylic Ester 9 
 Butea, 212 
 Butea frondosa, 628 
 Butein, 628 
 Butenyl-benzol, 406 
 Butryl-phenyl-acetylene, 417 
 Butyl-benzol, 59 
 Buzylene, 168 
 
 CADINENE, 547 
 
 Cczsalpina coriaria, 340 
 
 Caffeic Acid, 429 
 
 Calcium phenate, 186 
 
 Sah'cylate, 329 
 
 Camphane, 513, 525 
 
 Camphane-diamine, 529 
 
 Camphanic Acid, 541 
 
 Camphanonazine, 533 
 
 Camphel Alcohol, 527 
 
 Camphelamine, 537 
 
 Camphenamine, 529 
 
 Camphene, 522 
 
 Camphene Dibromide, 522 
 
 Camphene-glycol, 522 
 
 Camphene Hydrate, 527 
 
 Hydrochloride, 522 
 
 Camphenilane-aldehyde, 523 
 
 Camphenilanic Acids, 523 
 
 Camphenile Nitrite, 522 
 
 Camphenilol, 528 
 
 Camphenilone, 523 
 
 Camphenone, 534 
 
 Camphenylamine, 529 
 
 Campherol, 534 
 
 3amphidin, 540 
 
 3amphidonene, 540 
 
 "ampho-acid, 544 
 Campho-carboxyUc Acid, 534 
 
 -.ampho-ceanic Ring, 14 
 
 3ampho-pyro-acid, 544 
 Camphol, 526 
 Alcohol, 527 
 
 ^ampholamine, 529, 537 
 Camphplene, 539 
 Dibromide, 539 
 
 "ampholenic Acid, 14, 538 
 Campholic Acid, 537 
 Campholide, 544 
 
INDEX 
 
 735 
 
 Campholytic Acid, 14, 543 
 Camphor, 14, 443, 529 
 
 Dichlorides,532 
 
 Camphor-dioxime, 533 
 Camphor-glycol, 534 
 
 Camphor-methylene-carboxylic Acid, 536 
 Camphor-nitrilic Acid, 541 
 Camphor-oxalic Acid, 537 
 Camphor-oxime, 532 
 Camphor-phenyl-hydrazone, 533 
 Camphor-quinone, 533 
 Camphor-quinone-phenyl-hydrazone, 533 
 Camphor-sulphonic Acids, 532 
 Camphoranic Acid, 545 
 Camphoric Acid, 14, 21. 539, 541 
 Camphorimine, 532, 533 
 Camphorone, 540 
 Camphoronic Acid, 545 
 Camphorphorone, 14 
 Camphoryl-carbamide, 534 
 Camphoryl-dimethyl-carbinol, 537 
 Camphoryl-glycocoll Ester, 534 
 Camphoryl-hydroxylamine, 541 
 Camphoryl-iso-cyanate, 534 
 Camphoryl-malonic Acid Ester, 544 
 Camphoryl-methyl-carbinol, 536 
 Camphoryl-mustard Oil, 534 
 Camphyl-glycols, 536 
 Camphylamine, 528, 538 
 Cantharene, 450 
 Cantharic Acid, 724 
 Cantharidin, 724 
 Cantharinic Acid, 724 
 Caoutchouc, 549 
 Carane, 513 
 
 Carbamic Acid Derivatives, 161 
 Carbaminic a-phenyl-hydrazide, 160 
 
 Ethyl Ether, 100 
 
 Carbanile, 99, 104 
 
 Carbanilic Acid 99 
 
 Carbanilide, 99 
 
 Carbinol-benzoic Acids, 347 
 
 Carbinols, 579 
 
 Carbo-benzoyl-propionic Acid, 402 
 
 Carbo-diazone, 142 
 
 Carbo-diphenyl-imide, 106 
 
 Carbo-mandeh'c Acid, 401 
 
 Carbo-methoxy-salicylic Acid, 330 
 
 Carbo-phenyl-glyoxylic Acid, 402 
 
 Carbodi-p-tolyl-imide, 107 
 
 Carbolic Acid, 185 
 
 Carbonate, 125 
 
 Carbonyl-benzamide, 282 
 
 Carbonyl-salicyl-amide, 332 
 
 Carbostvrilic Acid, 305 
 
 Carboxy-phenyl-trimethylene-dicarboxyh'c Acid, 
 
 642 
 
 Carboxyl-anthranilic Dimethyl Ester, 304 
 Carboxyl-apo-camphoric Acid, 524, 544 
 Carboxylic Acids, 631 
 Carminazarin, 728 
 Carminic Acid, 727 
 Carnation Acid, 41 1 
 Caro, 586 
 Carone, 514 
 Caronic Acid, 80 
 Carro-menthene, 449 
 Carthamin, 727 
 Carthamus tinctorium, 727 
 Carva-crotinic Acids, 335 
 Carvacrol, 188 
 Carvene, 491 
 Carvenolidene, 509 
 Carvenone, 507 
 Carvenylamine, 504 
 Carveol. 507 
 
 Carveol-methyl Ether, 503 
 Carvestrene, 496 
 Carvo-menthene, 496 
 Carvo-menthol, 498 
 Carvo-menthylamine, 504 
 Carvo-pinone, 521 
 Carvone, 25 
 Carvotan-acetone, 507 
 Carvoxime, 510 
 Carvum carvi, 188 
 
 Caryo-phyllene, 547 
 Castoreum, 186 
 Catechin, 338 
 Catechinic Acid, 343 
 Catechu-tannin, 343 
 Caucasian Petroleum, 14 
 Cedriret, 558 
 Cedrol, 548 
 Centric Scheme, 41 
 Cetyl-benzol, 60 
 Chamterops humilis, 453 
 Chavibetol, 411 
 Chavica Betle, 409 
 Chavicol, 409 
 Chloraceto-phenone, 268 
 Chloraceto-pyro-catechin, 373 
 Chloranilamic Acid, 230 
 Chloranile, 229 
 Chloranile-amide, 229 
 Chloranilic Acid, 230 
 Chloraniline-o-siilphomc Acid, 93 
 Chloranilino-triphenyl-amine, 116 
 Chlorindazol, 312 
 Chloro-aceto-phenone, 371 
 Chloro-anthraquinone, 710 
 Chloro-benzene, 29 
 Chloro-benzile, 618 
 Chloro-benzol Hexachloride, 447 
 Chloro-benzols, 61 
 Chloro-benzyl-aceto-phenone, 628 
 Chloro-benzyl Chloride, 30 
 Chloro-bromo-benzols, 62 
 Chloro-bromo-stilbene, 620 
 Chloro-camphor, 532 
 Chloro-cinnamic Acids, 421, 422 
 Chloro-diazo-benzol Anhydride, 126 
 
 Sulphocyanide, 125 
 
 Chloro-i, 2-diketo-pentamethylene, 18 
 Chloro-diphenacyl, 634 
 Chloroform, 48 
 Chloro-hydrin, 369 
 Chloro-methyl-benzamide, 348 
 Chloro-methyl-benzanilide, 348 
 Chloro-methyl-benzo-nitrile, 348 
 Chloro-methyl-benzoic Acid, 348 
 Chloro-methylene camphor, 536 
 Chloro-naphthalenes, 658 
 Chloro-naphthalene-sulphonic Acids, 664 
 Chloro-nitro-benzol, 76 
 Chloro-2-nitro-toluol, 74 
 Chloro-4-nitro-toluol, 74 
 Chloro-5-nitro-toluol, 74 
 Chloro-p-oxy-benzyl Alcohol, 316 
 Chloro-phenyl-hydrazin, 150 
 Chloro-phenyl-hydrazo-aldoximes, 165 
 Chloro-phenyl-hydroxylamine, 78 
 Chloro-sah'cyl Chloride, 331 
 Chloro-salicylic Acid, 333 
 Chloro-stilbene Dichloride, 619 
 Chloro-styrol, 405 
 Chloro-toluol, 30, 65 
 Chloryl-phthalimide, 357 
 Cholesterin, 548 
 Chrysamic Acid, 724 
 Chrysamine, 555 
 Chrysammic Acid, 716 
 Chrysanisic Acid, 309 
 Chrysarobin, 716 
 Chrysazin, 716 
 Chrysazine, 706 
 Chrysazol, 705, 706 
 Chrysene, 693, 694 
 Chrysene-fluorene, 695 
 Chryso-diphenic Acid, 694 
 Chryso-fluorene, 697 
 Chryso-ketone, 694, 699 
 Chryso-ketone-carboxyh'c Acid, 701 
 Chryso-quinone, 694 
 Chrysopham'c Acid, 716 
 Cicuta virosa, 58, 429 
 Cinene, 491 
 Cinenic Acid, 500 
 Cineol, 499, 500 
 Cineolic Acid, 500 
 Cinnamal-lasvulinic Acid, 439 
 Cinnamenyl-acrylic Acid, 433 
 
736 
 
 Cinnamenyl-dihydro-resorcin, 459 
 Cinnamenyl-glutaric Acid, 441 
 Cinnamenyl-itaconic Acid, 441 
 Cinnamenyl-paraconic Acid, 441 
 Cinnamenyl-succinic Acid, 441 
 Cinnamic Acid, 419 
 
 Dibromide, 385 
 
 Bichloride, 385 
 
 Aldehyde, 415 
 
 Cinnamomum camphor a, 529 
 
 ceylanicum, 415 
 
 Cinnamyl-acetone, 417 
 Cinnamyl Alcohol, 413 
 Cinnamyl-carboxylic Acid, 436 
 Cinnamyl Cyanide, 437 
 Cinnamyl-formic Acid, 437 
 Cinnamylene-benzylidene-acetone, 640 
 Cinnamylidene-acetic Acid, 433 
 Cinnamylidene-aceto-phenone, 639 
 Cinnamylidene-fluorene, 696 
 Cinnamylidene-indene, 643 
 Cinnamylidene-malonic Acid 440 
 Cinnamylidene-propionic Acid, 433 
 Cinnamylidene-succinic Acid, 441 
 Cis-cyclopentane-i, 3-dicarboxylic Acid, 20 
 Citral, 42, 490 
 
 Citralidene-malonic Ester, 43 
 Citrene, 491 
 Citronellal, 489 
 Citronellic Acid, 490 
 Citronellol, 488 
 Citrus aurantium, 491 
 
 Bergamia, 435 
 
 decumana. 723 
 
 Claus, 41 
 Coal-tar, 50 
 Coccoloba uvifera, 343 
 Cochinelic Acid, 728 
 Cocos nucifera, 454 
 
 plumosa, 454 
 Cocosate, 454 
 Codem, 689 
 Coerulignone, 558 
 Colophony, 548 
 Congo Red, 664 
 
 Yellow, 555 
 
 Coniferin. 721 
 Coniferyl Alcohol, 414, 721 
 Conrad, 418 
 Convolvulin, 722 
 Convolvulus orizabensis, 722 
 
 purga, 722 
 
 Copper-methyl-phenyl-triazene, 136 
 Coriander Oil, 488 
 Cornicularic Acid, 635 
 Cotarnic Acid, 359 
 Coto, 573 
 
 Bark, 437 
 
 Co torn, 573 
 Couper, 28 
 Crafts, 52 
 Creosol, 214 
 Cresols, 187 
 Cresol Benzein, 591 
 Cresotinic Acids, 334 
 
 Chloride, 331 
 
 Croconic Acid, 14, 222, 224, 232 
 
 Hydride, 232 
 
 Croton-aldehyde, 255 
 Crotonylene, 42 
 Crystal Violet, 587 
 Cubebin, 414 
 Cudbear, 217 
 Cumarandione, 390 
 Cumaric Acid, 427, 429 
 
 Aldehyde, 415 
 
 Dimethyl Ether, 427 
 Cumarilic Acid, 428 
 Cumarin, 328, 427 
 
 Bromide, 428 
 
 Cumarin-carboxylic Amide, 440 
 Cumarin Homologues, 428 
 Cumarin-monomethyl-ester Acid, 428 
 Cumarin-propionic Acid, 441 
 Cumarines, 185 
 Cumarinic Dimethyl Ester, 428 
 
 INDEX 
 
 Cumaro-ketone, 417 
 
 Cumarone, 414 
 
 Cumaroxime, 428 
 
 Cumic Acid, 256 
 
 Cumic Aldehyde, 256 
 
 Cuminal-acetone, 417 
 
 Cuminic Acid, 275 
 
 Cuminile, 619 
 
 Cuminilic Acid, 607 
 
 Cuminoin, 615 
 
 Cuminol, 256 
 
 Cuminum cymimim, 58 
 
 Cumol, 55, 57 
 
 Cumyl Alcohol, 256 
 
 Cumyl-ethyl-amine, 246 
 
 Cuprous Bromide, 124 
 
 Curcuma tonga, 727 
 
 Curcumin, 727 
 
 Cyan-amidrazone, 168 
 
 Cyan-anilide ; 106 
 
 Cyan-o-toluic Acid, 363 
 
 Cyanated Carbinol, 583 
 
 Cyano-benzo-hydrol, 574 
 
 Cyano-benzoic Acid, 358, 360, 362 
 
 Cyano-benzoic Acid Ester, 358 
 
 Cyano-benzol-sulphonic Acid, 313 
 
 Cyano-benzyl Chloride, 348 
 
 Cyano-benzyl Cyanide, 363 
 
 Cyano-benzyl-rhodanide, 349 
 
 Cyano-camphor, 535 
 
 Cyano-carone, 514 
 
 Cyano-cinnamic Acid, 435, 439 
 
 Cyano-cumarin, 439 
 
 Cyano-cyclopentanone, 22 
 
 Cyano-diphenyl-methane, 574 
 
 Cyano-formanilide, 107 
 
 Cyano-2-keto-pentamethylene-carboxylic Ester, 22 
 
 Cyano-lauronic Acid, 541 
 
 Cyano-methylene-camphor, 536 
 
 Cyano-naphthalenes, 68 1 
 
 Cyano-phenanthrene, 691 
 
 Cyano-phenin, 290 
 
 Cyano-phenyl-hydrazin, 160, 312 
 
 Cyano-trimethylene-carboxylic Acid, 9 
 
 Cyano-triphenyl-methane, 595 
 
 Cyclic Amidines, 116 
 Diazides, 178 
 
 Guanidin Derivatives, 116 
 
 Ketone Formation, 5 
 
 Syntheses with Malonic Acid Esters, Acetic 
 
 Acid Esters, etc., 5 
 
 with the aid of Metallorganic com- 
 pounds, 4 
 
 Ureas, 116, 161 
 
 Cyclo-butane, i, 6 
 
 Cyclo-butanol, 7, n 
 
 Cyclo-butene, 10 
 
 Cyclo-citral, 467 
 
 Cyclo-formazyl-carboxylic Ester, 556 
 
 Cyclo-geranic Acid, 472, 490 
 
 Cyclo-geraniolene, 449 
 
 Cyclo-heptadiene, 23 
 
 Cyclo-heptadiene-carboxylic Acid, 24 
 
 Cyclo-heptane, i, 6, 23 
 
 Cyclo-heptane-carboxylic Acid, 24 
 
 Cyclo-heptanol, 23 
 
 Cyclo-heptanol-acetic Acid, 25 
 
 Cyclo-heptanone, 24 
 
 Cyclo-heptatriene, 23 
 
 Cyclo-heptatriene-carboxylic Acids, 24 
 
 Cyclo-heptene, 23 
 
 Cyclo-heptene-carboxylic Acid, 24 
 
 Cyclo-heptenol-ethyl Ether, 23 
 
 Cyclo-hexadienes, 449, 450 
 
 Cyclo-hexanes, i, 6, 444, 445 
 
 Cyclo-hexane-diones, 459, 460 
 
 Cyclo-hexane-triones, 460 
 
 Cyclo-hexanol, 452, 454 
 
 Cyclo-hexanol-acetic Acid, 474 
 
 Cyclo-hexanolone, 458 
 
 Cyclo-hexanone-carboxylic Acid, 475 
 
 Cyclo-hexanone-pimelin-ketone, 457 
 
 Cyclo-hexenes, 447 448 
 
 Cyclo-hexene-acetic Acid, 473 
 
 Cyclo-hexenone, 461 
 
 Cyclo-hexenone-carboxylic Acid, 476 
 
INDEX 
 
 737 
 
 Cyclo-hexyl-aceto-acetic Ester, 476 
 Cyclo-hexyl-acetone, 468 
 Cyclo-hexyl-acetylenes, 45 1 
 Cyclo-hexyl-allylene, 451 
 Cyclo-hexyl-amine, 455 
 Cyclo-hexyl-aniline, 455 
 Cyclo-hexyl Ether, 452 
 Cyclo-hexyl-glycidic Esters, 475 
 Cyclo-hexyl-malonic Acid, 477 
 Cyclo-hexyl Mercaptan, 455 
 Cyclo-hexyl-methyl-amine, 456 
 Cyclo-nonane, i, 6, 26 
 Cyclo-nonanol, 26 
 Cyclo-nonanone, 26 
 Cyclo-octadiene, 25 
 Cyclo-octane, i, 6, 25 
 Cyclo-octanone, 26 
 Cyclo-paraffins, i, 4 
 Cyclo-pentadiene, 13, 15 
 Cyclo-pentane, i, 6 
 Cyclo-pentane-aldehyde, 19 
 Cyclo-pentane-carboxylic Acid, 19 
 Cyclo-pentane- 1, 2-dicarboxylic Acid, 13, 20 
 
 i, 2, 4-tricarboxylic Acid, 20 
 Cyclo-pentanol, n, 16 
 Cyclo-pentanol Acid Ester, 21 
 Cyclo-pentanol-isobutyric Ester, 21 
 Cyclo-pentanol-propionic Ester, 2 1 
 Cyclo-pentanone, 17 
 Cyclo-pentenaldehyde, 19 
 Cyclo-pentene, 14 
 Cyclo-pentene-acetic Acid, 20 
 Cyclo-pentene-carboxylic Acid, 20 
 Cyclo-pentene- 1, 2-dicarboxylic Acid, 20 
 Cyclo-pentene-propionic Acid, 20 
 Cyclo-pentenol Acetate, 17 
 Cyclo-pentenolone, 18 
 Cyclo-propane, i, 6, 7 
 Cymo-phenol, 188 
 Cymol, 55, 58 
 CysteTn, 283 
 Cystin, 283 
 
 D&monorops Draco, 273 
 Dale, 586 
 Dambonite, 454 
 Daphne alpina, 721 
 
 mezereum, 430 
 
 Daphnetin, 431 
 Daphnin, 721 
 
 Deca-hydro-acenaphthene, 683 
 Deca-hydro-naphthylamine, 687 
 Decarboxy-dibromo-carminic Acid, 728 
 Dehydracetic Acid, 43 
 Dehydro-benzal-phenyl-hydrazone, 167 
 Dehydro-camphoric Acid, 542 
 Dehydro-nchtelite, 693 
 Desmo-tropo-santonins, 725 
 Desoxy-anisoln. 614 
 Desoxy-benzoin, 613 
 Desoxy-toluom, 613 
 Dessaignes, 282 
 Desyl-acetic Acid, 622 
 Desyl-aceto-phenone, 634 
 Desyl-anilide, 616 
 Desyl-bromide, 616 
 Desylene-acetic Acid, 622 
 Diacetanilide, 95 
 Diaceto-benzidin, 554 
 Diaceto-caffeic Acid, 430 
 Diaceto-phenol-phthalem, 598 
 Diaceto-phenyl-hydrazide, 157 
 Diaceto-resorcin, 347 
 Diacetonyl-dibenzyl, 623 
 Diacetyl, 43 
 Diacetyl-benzol, 347 
 Diacetyl Compound, 727 
 Diacetyl-dioxy-stilbene, 619 
 Diacetyl-mesitylene, 347 
 Diacetyl-phenetidin, 202 
 
 Diacetyl-tetramethylene-dicarboxylic Ester, 12 
 Diacid Alcohols, 499 
 Diacyl-diphenylene, 691 
 Diagonal Scheme, 41 
 Dialk-oxy-quinone, 227 
 
 VOL. II. 
 
 Dialkyl-2, 3-dicyano-trimethylene-2, 3-dicarboxylic 
 
 Acids, 10 
 
 Dialkyl-phenanthrones, 691 
 Diamido-anthraquinones, 711 
 Diamido-azo-benzol, 144, 145 
 Diamido-azoxy-benzol, 140 
 Diamido-benzo-phenones, 571 
 Diamido-benzoic Acids, 310 
 Diamido-benzols, 35, 79, 114 
 Diamido-dibenzyl, 610 
 Diamido-diphenyl, 553, 554 
 Diamido-diphenyl-acetic Acid, 607 
 Diamido-diphenyl-amine, 116 
 Diamido-diphenyl-arsinic Acid, 170 
 Diamido-diphenyl Disulphide, 209 
 Diamido-diphenyl-methane, 564 
 Diamido-ditolyls, 147 
 Diamido-dixenylamine, 554 
 Diamido-fluorene, 697 
 Diamido-hydrazo-benzol, 146 
 Diamido-menthane, 504 
 Diamido-mesitylene, 115 
 Diamido-naphthalenes, 661 
 Diamido-phenanthrene, 690 
 Diamido-phenazin, 116 
 Diamido-phenols, 202 
 Diamido-pseudo-cumol, 115 
 Diamido-quinone Imine, 235 
 Diamido-stilbene, 612 
 Diamido-tolane, 613 
 Diamido-toluols, 115 
 Diamido-triphenyl-methane, 578 
 Diamines, 113 
 Diamine Black, 557 
 Dianilido-acetic Acid, 98 
 Dianilido-quinone Anile, 238 
 Dianilido-quinone Dianile, 227, 238 
 Dianilido-tolu-quinone, 231 
 Dianilino-fuchsone-anile, 589 
 Dianilino-guanidin, 162 
 Dianthra-quinonimides, 712 
 Dianthra-qiiinoyls, 717, 718 
 Dianthranilide, 304 
 Dianthranol, 707 
 Dianthrimides, 712 
 Diatropic Acids, 425 
 Diazo-aceto-phenone, 372 
 Diazo-alkali Salts, 124 
 Diazo-amido-benzoic Acids, 311 
 Diazo-amido-benzol, 135 
 Diazo-amido-compounds, 132 
 Diazo-amido-derivatives, Formation of, 132 
 Diazo-benzaldoxime Anhydride, 263 
 Diazo-benzoic Acids, 311 
 Diazo-benzol-amide, 134 
 Diazo-benzol Anhydride, 126 
 Diazo-benzol-anilide, 1 35 
 Diazo-benzol Bromide, 124 
 
 Chloride, 124, 156 
 
 Cyanide, 128 
 
 Diazo-benzol-dimethyl-amine, 136 
 Diazo-benzol-ethyl-amide, 136 
 Diazo-benzol-imide, 138 
 Diazo-benzol-imido-compounds, Transformations 
 
 of, 138 
 
 Diazo-benzol-methyl-amide, 135 
 Diazo-benzol Methyl Ether, 126 
 
 Nitrate, 125 
 
 Diazo-benzol-p-amido-bromo-benzol, 135 
 Diazo-benzol-p-amido-toluol, 135 
 Diazo-benzol perbromide, 125 
 
 Perchlorate, 125 
 
 Diazo-benzol-phenyl-hydrazide, 1 68 
 Diazo-benzol-piperidin, 136 
 Diazo-benzol Potassium, 126 
 
 Salts, 123 
 
 Sulphate, 125 
 
 Sulphocyanide, 125 
 
 Sulphonic Acid. 127 
 
 Diazo-benzol-sulphonic-acid Anhydrides, 178 
 Diazo-benzol Sulphoxide, 156 
 Diazo-benzol-thio-phenyl Ether, 208 
 Diazo-benzolic Acid, 120 
 
 Methyl Ester, 120 
 
 Diazo-compounds, 121 
 Diazo-cyanides, 142 
 
738 
 
 INDEX 
 
 Diazo-derivatives, Reactions of, 132 
 Diazo-group, Replacement of, by Halogens, 129 
 
 of, by Hydrogen, 129 
 
 of, by Hydroxyl, 130 
 
 of, by the Cyanogen Group, 131 
 
 of, by the Nitro-group, 131 
 
 of, by the Sulphinic Acid Residue, 131 
 
 of, by the Sulphydrate Group, 130 
 
 Diazo-hydrazo-compounds 168 
 Diazo-imido-benzoic Acids, 311 
 Diazo-imido-compounds, 137 
 Diazo-naphthalene Acid, 662 
 Diazo-naphthalin-imide, 662 
 Diazo-naphthalene-sulphonic Acid, 665 
 Diazo-oxy-amido-benzol, 137 
 Diazo-oxy-amido-compounds, 137 
 Diazo-per-halides, 125 
 Diazo -phenols, 203 
 Diazo-phenol Cyanide, 203 
 Diazo-pseudo-cumolic Acid, 120 
 Diazo- toluolic Acid, 120 
 Diazonium Salts, 124 
 Dibenzal-acetone, 638 
 Dibenzal-acetone Dichloride, 638 
 Dibenzal-diethyl-ketone, 638 
 Dibenzal-propio-phenone, 633 
 Dibenzamide, 281 
 Dibenzamidin-urea, 290 
 Dibenzenyl-azo-selenime, 289 
 Dibenzenyl-azoxime, 260, 295, 617 
 Dibenzo-hydrazide Chloride, 287 
 Dibenzo-hydryl-benzol, 576 
 Dibenzo-hydrylamine, 565 
 Dibenzol-sulphimide, 174 
 Dibenzol-sulphon-hydroxylamine, 1 75 
 Dibenzol-sulphone-dianthranilide, 304 
 Dibenzol-sulphone-hydrazin, 175 
 Dibenzoyl, 616 
 Dibenzoyl-acetic Acid, 631 
 Dibenzoyl-acetone, 630 
 Dibenzoyl-acetyl-methane, 630 
 Dibenzoyl-benzols, 576 
 Dibenzoyl-dibenzyl, 634 
 Dibenzoyl-diphenyl-butadiene, 640 
 Dibenzoyl-diphenyl-propane, 639 
 Dibenzoyl-ethane, 633 
 Dibenzoyl-fumaric Acid, 637 
 Dibenzoyl-maleic Acid Ester, 637 
 Dibenzoyl-malic Acid, 637 
 Dibenzoyl-malo-nitrile, 631 
 Dibenzoyl-methane, 630 
 Dibenzoyl-phenol-phthalein, 598 
 Dibenzoyl-propane, 639 
 Dibenzoyl-stilbene, 634 
 Dibenzoyl-styrol, 634 
 Dibenzoyl-succinic Acid, 636 
 Dibenzoylene-pyridin, 649 
 Dibenzyl, 27, 244, 609 
 Dibenzyl-acetic Acid, 631 
 Dibenzyl-aceto-phenone, 630 
 Dibenzyl-acetone-dicarboxylic Ester, 640 
 Dibenzyl, Alcohol and Ketone Derivatives of, 613 
 Dibenzyl-amine, 246 
 Dibenzyl-aniline, 247 
 Dibenzyl-anthracene, 704 
 Dibenzyl-benzenes, 576 
 Dibenzyl-carbinol, 628 
 Dibenzyl-carboxylic Acid, 621 
 Dibenzyl-dicarboxylic Acid, 622 
 Dibenzyl-ethane, 632 
 Dibenzyl-ethylamine, 631 
 Dibenzyl-fluorene, 696 
 Dibenzyl-glycolic Acid, 631 
 Dibenzyl Group, Carboxylic Acids of, 620 
 Dibenzyl-guanidin, 247 
 Dibenzyl, Homologues of, 610 
 Dibenzenyl-hydrazidin, 291 
 Dibenzyl-hydrazin, 248 
 Dibenzyl-ketone, 627 
 Dibenzyl-malonic Acid, 631 
 Dibenzyl-methane, 627 
 Dibenzyl-oxalate, 244 
 Dibenzyl-phenyl-carbinol, 628 
 Dibenzylidene-acetpne, 638 
 Dibenzylidene-succinic Acid, 636 
 Dibenzylindene, 645 
 
 Dibiphenylene-dibiphenyl-ethane, 627 
 Dibiphenylene-diphenyl-ethane, 697 
 Dibromaniline, no 
 Dibromo-anthranilic Acid, 73, 308 
 Dibromo-anthraquinone, 710, 712 
 Dibromo-butane, 7 
 Dibromo-camphor, 532 
 Dibromo-cinnamic Acids, 422 
 Dibromo-cyclo-butane, 10 
 Dibromo-cyclo-butene, 1 1 
 Dibromo-diazo-phenol, 203 
 Dibromo-diketo-R-pentene, 18 
 Dibromo-durol, 66 
 Dibromo-fluorene, 696 
 Dibromo-gallic Acid. 341 
 Dibromo-glyoxime Peroxide, 108 
 Dibromo-hydratropic Acid. 384 
 Dibromo-hydrindene, 648 
 Dibromo-hydro-bromide, 728 
 Dibromo-isodurol, 66 
 Dibromo-menthone, 505 
 Dibromo-mesitylene, 66 
 Dibromo-phenanthrene, 689 
 Dibromo-phenol-diazo-sulphonic Acid, 203 
 Dibromo-phthalic Acid, 358 
 Dibromo-prehnitol, 66 
 Dibromo-pseudocumol, 66 
 Dibromo-quinone Chlorimine, 235 
 Dibromo-quinone Phenol-imine, 236 
 Dibromo-stilbenes, 620 
 Dibromo-styrol, 405 
 
 Dibromo-tetramethylene-dicarboxylic Acid, 12 
 Dicarboxy-valero-lactonic Acid, 518 
 Dicarboxylic Acids, 354 
 Dichloracetamide, 48 
 Dichloracetic Acid, 221 
 Dichloraniline, no 
 Dichloranthrone, 707 
 Dichloro-anthranilic Acids, 308 
 Dichloro-acetyl-trichloro-crotonic Acid, 48 
 Dichloro-benzylidene-aceto-phenone, 628 
 Dichlorocamphanes, 532 
 Dichloro-camphor, 532 
 Dichloro-cinnamic Acid, 422 
 Dichloro-diketo-hydrindene, 649 
 Dichloro-dinitro-benzol, 72 
 Dichloro-hydrindene, 648 
 Dichloro-hydroquinone-disulphonic Acid, 219 
 Dichloro-maleic Acid, 47, 48 
 Dichloro-malonic Ester, 48 
 Dichloro-methyl-chloro-vinyl-o-diketone, 48 
 Dichloro-naphthalenes, 659 
 Dichloro-phenanthrene, 689 
 Dichloro-piperonal Chloride, 324 
 Dichloro-salicyl-chloride, 331 
 Dichloro-stilbene, 612, 619 
 Dichloro-styrol, 405 
 Dichloro-tolane, 613 
 Dichloro-toluol, 30 
 Dichloro-trimethylene, 7 
 Dichloro-vinyl-phenyl-iodonium Chloride, 64 
 Dichroins, 185 
 
 Dicinnamenyl-chloro-carbinol, 638 
 Dicinnamenyl-dichloro-methane, 638 
 Dicinnamylidene-succinic Anhydride, 640 
 Dicumarketone, 638 
 Dicyanamino-benzoyl, 305 
 Dicyano-benzol, 360, 362 
 Dicyano-phenyl-hydrazin, 163 
 Dicyano-hydroquinone, 227 
 Dicyano-stilbene, 623 
 Dicyclic Terpenes, 510 
 Dicyclo-hexyl, 550 
 Dicyclopentadiene, 15 
 Dicyclopentyl, 14 
 Diduro-quinone, 229 
 Diethyl-aniline, 89 
 Diethyl-aniline-sulphinic Acid, 181 
 Diethyl-anthranilic Acid, 306 
 Diethyl-anthrone, 706 
 Diethyl-carbinol, n 
 Diethyl-cyclo-hexane, 446 
 Diethyl-diketo-hydrindone, 649 
 Diethyl-diketo-tetramethylene-dicarboxylic Ester, 
 
 !3 
 
 Diethyl-diphenyl-tetrazone, 167 
 
INDEX 
 
 739 
 
 Diethyl Ester, 304 
 
 Diethyl-methyl-benzol, 59 
 
 Diethyl-phenols, 189 
 
 Diethyl-phenyl-hydrazin, 152 
 
 Diethyl-phenyl-hydrazonium Bromide, 151 
 
 Diethyl-proto-catechuic Acid, 338 
 
 Diethyl-terephthalyl 347 
 
 Diethyl-tetramethylene-ketone, 1 1 
 
 Difluoro-benzol, 61 
 
 Difluoro-chloro-toluol, 297 
 
 Diformazyl, 166 
 
 Digallic Acid, 343 
 
 Digitaligenin, 722 
 
 Digitalin, 722 
 
 Digitalinum verum, 722 
 
 Digitalis purpurea, 722 
 
 Digitalose, 722 
 
 Digito-flavone, 722 
 
 Digitogenin, 722 
 
 Digitonin, 722 
 
 Digitoxigenin, 722 
 
 Digitoxin, 722 
 
 Digitoxose, 722 
 
 Diglycol-anilic Acid, 98 
 
 Diglycol-phenyl-amidlc Acid, 98 
 
 Diglycol-phenyl-amidic Anhydride, 98 
 
 Diglycolic Anile, 98 
 
 Dihalogen-anthracenes, 704 
 
 Dihaloids, 369 
 
 Dihippenyl-urea, 284 
 
 Dihydrazone, 649 
 
 Dihydro-anthranol, 709 
 
 Dihydro-benzaldehyde, 467 
 
 Dihydro-benzoic Acids, 472 
 
 Dihydro-benzols, 449, 450 
 
 Dihydro-camphene-pyrazin, 534 
 
 Dihydro-campholene-lactone, 538 
 
 Dihydro-campholenic Acid, 539 
 
 Dihydro-carvone, 506 
 
 Dihydro-cumin Alcohol, 454 
 
 Dihydro-cumin-aldehyde, 467 
 
 Dihydro-dicarboxylic Acids, 479 
 
 Dihydro-diphenyl, 550 
 
 Dihydro-diphthalyl-di-imide, 621 
 
 Dihydro-eucarveol, 514 
 
 Dihydro-eucarvone, 514 
 
 Dihydro-fencholene, 526 
 
 Dihydro-iso-phorol, 462 
 
 Dihydro-m-xylol, 450 
 
 Dihydro-methyl-trimesinic Acid, 483 
 
 Dihydro-myrcene, 487 
 
 Dihydro-naphthacene, 719 
 
 Dihydro-naphthalene, 683 
 
 Dihydro-naphthalene Derivatives, 683 
 
 Dihydro-naphthalene Dibromide, 686 
 
 Dihydro-naphthoic Acids, 684 
 
 Dihydro-o-xylol, 450 
 
 Dihydro-phenanthrene, 691 
 
 Dihydro-pheno-triazin, 144 
 
 Dihydric Phenols, 211 
 
 Dihydro-pinylamine, 521 
 
 Dihydro-quinazolin, 251 
 
 Dihydro-resorcin, 215 459 
 
 Dihydro-salicylic Acid, 476 
 
 Dihydro-shikimic Acid, 474 
 
 Dihydro-terephthalic Acids, 480 
 
 Dihydro-terpinolene, 497 
 
 Dihydro-toluol, 450 
 
 Dihydro-umbellulone, 513 
 
 Dihydro-uvitinic Acid, 483 
 
 Di-iodanih"ne, no 
 
 Di-iodo-camphor, 532 
 
 Di-iodo-cinnamic Acid, 422 
 
 Di-iodo-di-thymol, 188 
 
 Di-iodo-styrol, 405 
 
 Diketo-hexamethylenes, 459 
 
 Diketo-hydrindene, 649 
 
 Diketo-hydrindene-carboxylic Ester, 650 
 
 Diketo-pentamethylene, 18 
 
 Diketo-pentamethylene-3, 5-dicarboxylic Ester, 22 
 
 Diketo-pentamethylene-3, 4, 5-tricarboxylic Ester, 
 
 22 
 
 Diketo-tetrahydro-naphthylene Oxide, 672, 686 
 Diketone-carboxylic Acids, 395 
 Diketones, Intramolecular formation of, 5 
 Dilliso-apiol, 412 
 
 Dimethoxy-phenanthrene, 690 
 Dimethoxy-phthalazone, 352 
 Dimethoxy-tolane, 613 
 Dimethyl-amido-anthrone, 707 
 Dimethyl-amido-azo-benzol-[4]-sulphonic Acid, 179 
 Dimethyl-amido-triphenyl-me thane, 578 
 Dimethyl-amino-cycloheptene, 24 
 Dimethyl-amino-triphenyl-carbinol, 583 
 Dimethyl-aniline, 89, 169 
 
 Oxide, 90 
 
 Dimethyl-aniline-sulphinic Acid, 181 
 Dimethyl-anthracene, 704 
 Dimethyl-anthranih'c Acid, 306 
 Dimethyl-anthrarufin, 716 
 Dimethyl-apionol, 223 
 Dimethyl-aurin, 593 
 Dimethyl-beozamide Chloride, 287 
 Dimethyl-benzidin, 554 
 Dimethyl-benzoic Acids, 275 
 Dimethyl-benzols, 30, 35 
 Dimethyl-caff eic Acid, 430 
 Dimethyl-camphor, 536 
 Dimethyl-cyclo-hexadiene, 450 
 Dimethyl-cyclo-hexane, 446 
 Dimethyl-cyclo-hexene, 449 
 Dimethyl-cyclopentane-carboxylic Acid, 19 
 Dimethyl-cyclopentanone, 17 
 Dimethyl-diamino-triphenyl-carbinol, 583 
 Dimethyl-dibenzyl, 610 
 Dunethyl-i, 2-diketo-pentamethylene-3, 5- di- 
 
 carboxylic Acid, 22 
 
 Dimethyl-2, 4-diketo-tetramethylene, n 
 Dimethyl-2, 4-diketo - tetramethylene - carboxylic 
 
 Ester, 13 
 
 Dimethyl-4, 5-diphenyl-cyclopentanone, 17 
 Dimethyl-diphenyl-tetrazone, 167 
 Dimethyl Ether, 727 
 Dimethyl-fulvene, 15 
 Dimethyl-gentisin Alcohol, 320 
 Dimethyl-heptinol, 449 
 Dimethyl-hydro-phthalide, 345 
 Dimethyl-hydro-resorcin, 460 
 Dimethyl-methylene-tetramethylene, 1 1 
 Dimethyl-methylene-trimethylene, 7 
 Dimethyl-morphol, 690 
 Dimethyl-norcaradiene-carboxylic Ester, 641 
 Dimethyl-pen tamethylene, n, 14 
 Dimethyl-4 -keto-pentamethylene-carboxylic Acid, 
 
 22 
 
 Dimethyl-phenanthrene, 689 
 Dimethyl-phenyl-betain, 98 
 Dimethyl-phenyl-hydrazin. 152 
 Dimethyl-phenyl-oxy - ammonium - chlorohydrate , 
 
 88 
 
 Dimethyl-phenylene Green, 239 
 Dimethyl-phthaUde, 349 
 Dimethyl-phthalide-carboxylic Acid, 725 
 Dimethyl-quinol, 320 
 Dimethoxy-quinone Oxime, 222 
 Dimethyl-tert.-cyclopentanol, 16 
 Dimethyl-tetramethylene-ketone, 1 1 
 Dunethyl-tolane, 613 
 Dimethyl- tricarballylic Acid, 517 
 Dimethyl-trimethylene, 7 
 Dimethyl-trim thylene-carboxylic Acid, 8 
 Dimethyl-trimethylene-2, 3-dicarboxylic Acid, 10 
 Dimethyl-umbelHferone, 430 
 Dinaphtho-fluorene, 682 
 Dinaphtho-fluorenone, 699 
 Dinaphtho-xanthene, 682 
 Dinaphthol-methane, 682 
 Dinaphthyls, 681 
 Dinaphthyl-acetic Acid, 682 
 Dinaphthyl-carbinoL 682 
 Dinaphthyl Ethers, 666 
 Dinaphthyl-methane, 68 1 
 Dinaphthyl Sulphides, 671 
 Dinaphthylamine, 660 
 Dinaphthylene-methanes, 695 
 Dinaphthylene-thiophene, 683 
 Dinitraniline, in 
 Dinitro-aceto-phenone, 269 
 Dinitro-anthracene, 704 
 Dinitro-anthraquinone, 710 
 Dinitro-azo-benzol, 142 
 Dinitro-azoxy-benzol, 140 
 
740 
 
 INDEX 
 
 Dinitro-benzaldehyde, 262 
 Dinitro-benzoic Acid, 299 
 Dinitro-benzols, 70, 77 
 Dinitro-benzol-azo-benzol, 142 
 Dinitro-benzyl-acetic Acid, 631 
 Dinitro-chloro-benzol, 72 
 Dinitro-cinnamic Acid, 423 
 Dinitro-diazo-amido-benzol, 135 
 Dinitro-dibenzyl, 610 
 Dinitro-dibenzyl-acetone, 638 
 Dinitro-dichloro-benzols, 72 
 Dinitro-dinitroso-benzol, 77 
 Dinitro-diphenic Acid, 561 
 Dinitro-diphenyl-amine, 112 
 Dinitro-diphenyl-hydroxylamine, 78 
 Dinitro-durol, 74 
 Dinitro-ethyl-benzol, 73 
 Dinitro-hydroquinone, 219 
 Dinitro-isodurol, 74 
 Dinitro-m-xylol, 73 
 Dinitro-mesitylene, 73 
 Dinitro-naphthalene, 659 
 Dinitro-o-xylol, 73 
 Dinitro-oxanilide, 108 
 Dinitro-p-tolyl-methyl-nitramine, 120 
 Dinitro-p-xylol, 73 
 Dinitro-phenols, 196 
 Dinitro-phenol Ether, 191 
 Dinitro-phenyl-hydroxylamine, 78 
 Dinitro-phenyl-malonic Ester, 396 
 Dinitro-phenyl-nitramine, 121 
 Dinitro-prehnitol, 74 
 Dinitro-pseudocumol, 73 
 Dinitro-stilbene, 612 
 Dinitro- toluol, 72, 73 
 Dinitro-trichloro-benzol, 72 
 Dinitroso-benzol, 77 
 Dinitroso-naphthalene, 659 
 Dinitroso-toluol, 76 
 Dios-phenol, 508 
 Dioxindol, 378 
 Dioxy-anthracene, 708 
 Dioxy-anthra-cumarin, 708 
 Dioxy-anthraquinones, 714, 716 
 Dioxy-anthrone, 707 
 Dioxy-azo-benzol, 206 
 Dioxy-benzal-diketo-hydrindene, 649 
 Dioxy-benzaldehydes, 323 
 Dioxy-benzo-phenones, 226, 573 
 Dioxy-benzoic Acids, 336 
 Dioxy-benzols, 30, 35, 117 
 Dioxy-benzyl Alcohols, 320 
 Dioxy-benzyl-amine, 321 
 Dioxy-biphenyls, 556 
 Dioxy-cinnamic Acid, 431 
 Dioxy-dibenzal-acetone ; 638 
 Dioxy-dihydro-shikimic Acid, 474 
 Dioxy-dimethyl-triphenyl-methane, 590 
 Dioxy-dinaphthyl Sulphide, 671 
 Dioxy-diphenyl, 557 
 Dioxy-diphenyl-methane, 565 
 Dioxy-diphenyl-sulphone, 180, 227 
 Dioxy-diquinoyl, 231 
 Dioxy-durylic Acid, 339 
 Dioxy-hexahydro-terephthalic Acid, 481 
 Dioxy-hydro-campholenic Acid, 538 
 Dioxy-iso-phthalic Acid, 361 
 Dioxy-m-xylo-quinone, 231 
 Dioxy-methyl-anthraquinone, 716 
 Dioxy-monocarboxylic Acids, 336 
 Dioxy-naphthacene-quinone, 719 
 Dioxy-naphthalene, 670, 671 
 Dioxy-naphthoic Acid, 679 
 Dioxy-phenanthrene-quinone, 693 
 Dioxy-phenyl-acetic Acid, 340 
 Dioxy-phenyl-fatty Acids, 339 
 Dioxy-phenyl-olefin-carboxylic Acids, 429 
 Dioxy-phthalimide, 359 
 Dioxy-quinone, 230 
 Dioxy-quinone-dicarboxylic Ester, 482 
 Dioxy-stilbene, 612 
 Dioxy-terephthalic Acid, 362 
 Dioxy-terephthalic Ethyl Ester, 362 
 Dioxy-tetrazotic Acids, 290 
 Dioxy-thymo-quinone, 231 
 Dioxy-toluic Acids, 339 
 
 Dioxy-triphenyl-carbinol, 591 
 Dioxy-triphenyl-methane, 590 
 Dipentamethenyl, 14 
 Dipentene, 491 
 Diphenacyl, 633 
 
 Diphenacyl-aceto-acetic Ester, 639 
 Diphenacyl-amine, 372 
 Diphenamino Acid, 561 
 Diphenanthryl-azin y 690 
 Diphenic Acid, 560 
 
 Anhydride, 561 
 
 Chloride, 561 
 
 Diphenimide, 561, 692 
 
 Diphenin, 146 
 
 Diphenol-ethane, 604 
 
 Diphenoxy-acetic Acid, 191 
 
 Diphenyl, 27, 550 
 
 Diphenyl-acenaphthenone, 683 
 
 Diphenyl-acet-amidin, 95 
 
 Diphenyl-acetic Acid, 606, 639 
 
 Diphenyl-aceto-nitrile, 606 
 
 Diphenyl-acetone, 605 
 
 Diphenyl-acetylene, 613 
 
 Diphenyl-aconic Acid, 608 
 
 Diphenyl-adipic Acid, 623 
 
 Diphenyl-anthracene, 704 
 
 Diphenyl-anthranilic Acid, 306 
 
 Diphenyl-anthraquinone-methane, 706 
 
 Diphenyl-anthrone, 707 
 
 Diphenyl-arsenious Chloride, 170 
 
 Diphenyl-arsinic Acid, 170 
 
 Diphenyl-barbituric Acid, 109 
 
 Diphenyl-benzamide, 282 
 
 Diphenyl-benzamidin, 290 
 
 Diphenyl-benzols, 562 
 
 Diphenyl-benzyl-sultame, 581 
 
 Diphenyl-biguanide, 104 
 
 Diphenyl-bismuth Iodide, 170 
 
 Diphenyl-biuret, 100 
 
 Diphenyl-boron Bromide. 170 
 
 Diphenyl-boron Chloride, 170 
 
 Diphenyl-bromo-methane. 565 
 
 Diphenyl-butadiene, 632, 640 
 
 Diphenyl-butadiene-acetic Acid, 636 
 
 Diphenyl-butenin, 633 
 
 Diphenyl-butenone, 633 
 
 Diphenyl-butylene, 632 
 
 Diphenyl-butyric Acid, 608 
 
 Diphenyl -butyro-lactone, 631 
 
 Diphenyl-carbazide, 160 
 
 Diphenyl -carbazide-dicarboxylic Ester, 160 
 
 Diphenyl-carbazone, 160 
 
 Diphenyl-carbinol, 565 
 
 Diphenyl-carbinol Chloride, 565 
 
 Diphenyl-carbo-diazone, 160 
 
 Diphenyl -chloro-methane, 565 
 
 Diphenyl-citraconic Acid, 608 
 
 Diphenyl Compounds, Formation of, from Diazo- 
 
 derivatives, 131 
 Diphenyl-croto-lactone, 608 
 Diphenyl Cyanamide, 106 
 Diphenyl-cyclopentane, 18 
 Diphenyl-cyclopentenolone, 17, 638 
 Diphenyl-cyclopentenolone-acetic Acid, 17 
 Diphenyl-diacetylene, 633 
 Diphenyl-diacipiperazine, 97 
 Diphenyl-dibromo-quino-methane, 591 
 Diphenyl-diethylene, 632 
 Diphenyl-dihydro-anthracene, 707, 709 
 Diphenyl-dihydro-resorcin, 459 
 Diphenyl-diketo-hexane, 640 
 Diphenyl-diketo-nonane, 640 
 Diphenyl-diketo-octane, 640 
 Diphenyl-dimethyl-ethane, 610 
 Diphenyl-dinitro-butylene, 632 
 Diphenyl-dinitro-ethane, 611 
 Diphenyl-dinitro-methane, 569 
 Diphenyl-dioxy-anthracene Hydride, 709 
 Diphenyl-ethane, 603 
 Diphenyl-ethenyl-amidin, 97 
 Diphenyl-ethylene, 610 
 Diphenyl-ethylene-chlorp-hydrin, 605 
 Diphenyl-ethylene-diamine, 615 
 Diphenyl-ethylene Oxide, 615 
 Diphenyl-fonnamidin, 96, 97 
 Diphenyl-fulvene, 15 
 
INDEX 
 
 741 
 
 Diphenyl-furfurane, 633 
 Diphenyl-glutaric Acid, 623 
 Diphenyl-glycin-anhydride, 97 
 Diphenyl-glycolic Acid. 607 
 Diphenyl-glycolide, 377 
 Diphenyl-glyoxal, 616 
 Diphenyl -guanidin, 104 
 Diphenyl-hexadiene, 640 
 Diphenyl-hydantoin, 100 
 Diphenyl-hydrazin, 145, 146, 150, 167 
 Diphenyl-hydroxylamine, 78 
 Diphenyl-indone, 646 
 Diphenyl-iodonium Hydroxide, 61 
 
 Iodide, 6 4 
 Diphenyl-iso-butane, 610 
 Diphenyl-iso-dihydro-tetrazine, 158 
 Diphenyl-itaconic Acid, 608 
 Diphenyl-ketene, 605 
 Diphenyl-ketipic Acid, 637 
 Diphenyl-keto-tetrahydro-a-triazin, 158 
 Diphenyl-ketone, 567 
 Diphenyl-maleic Acid, 623 
 Diphenyl-malonyl-urea, 109 
 Diphenyl-methane, 27, 563, 602 
 Diphenyl-methane Carboxylic Acids, 574 
 Diphenyl-methyl-benzaldehyde, 594 
 Diphenyl-methyl-cyanidin, 290 
 Diphenyl-methyl-quino-methane, 591 
 Diphenyl-mono-biphenyl-carbinol, 580 
 Diphenyl-nitrosamine, 119 
 Diphenyl-nitroso-amine, 149 
 Diphenyl-octa-tetrene, 640 
 Diphenyl-oxalyl-diacetic Acid, 637 
 Diphenyl-oxethylamine, 615 
 Diphenyl Oxide, 191 
 Diphenyl-oxy-biazole, 617 
 Diphenyl-oxy-cyanidin, 290 
 Diphenyl-oxy-formamidin, 96 
 Diphenyl-oxyguanidin, 104 
 Diphenyl-parabanic Acid, 109 
 Diphenyl-pentamethylene, 14 
 Diphenyl-phenanthrene, 689 
 Diphenyl-phenol, 636 
 Diphenyl-phenylenes, 562 
 Diphenyl-phosphine, 169 
 Diphenyl-phosphine Chloride, 169 
 Diphenyl-phosphinic Acid, 169 
 Diphenyl-propane, 610 
 Diphenyl-propio-phenone, 629 
 Diphenyl-propionic Acid, 607, 608 
 Diphenyl-propylene, 627 
 Diphenyl-phthalide, 595 
 Diphenyl-pyridazin, 634 
 Diphenyl-quino-methane, 591 
 Dipheno-quinone, 558 
 Diphenyl Selenide, 183, 217 
 Diphenyl-selenium Oxide, 181 
 Diphenyl-selenone, 183 
 Diphenyl -semicarbazide, 160 
 Diphenyl-silicol, 171 
 Diphenyl Substitution Products, 551 
 Diphenyl -succinic Acid, 622 
 Diphenyl-sulphide, 183 
 Diphenyl-sulpho-carbazide, 162 
 Diphenyl-sulpho-carbazone, 142, 162 
 Diphenyl-sulpho-carbo-diazone, 162 
 Diphenyl-sulpho-semicarbazide, 1 6 1 
 Diphenyl-sulpho-urea, 102 
 Diphenyl-sulphone, 181, 182 
 Diphenyl-sulphone-phthalide, 355 
 Diphenyl-sulphoxide, 181, 182 
 Diphenyl Telluride, 211 
 Diphenyl-tetraketone, 635 
 Diphenyl-tetraketoxime, 635 
 Diphenyl-tetramethylene-dicarboxylic Acid, 13 
 Diphenyl-tetrazolium Hydroxide, 166 
 Diphenyl-tetrene-dicarboxylic Acid, 13 
 Diphenyl- tbio-carbonic Ester, 193 
 Diphenyl-trichloro-ethane. 604 
 Diphenyl-triketo-pentamethylene, 1 8 
 Diphenyl-triketone, 630 
 Diphenyl-uramile, 109 
 Diphenyl-urazin, 160, 161 
 Diphenyl-urea, 99, 100 
 
 Chloride, 99 
 
 Diphenyl-uric Acid, 109 
 
 Diphenyl-</-uric Acid, 109 
 Diphenyl- valeric Acid, 621 
 Diphenyl-violuric Acid, 109 
 Diphenylamine, 79, 91 
 
 Blue, 589 
 
 Diphenylene-acetic Acid, 700 
 Diphenylene-diketone, 709 
 Diphenylene-diphenyl-ethane, 698 
 Diphenylene-diphenyl-ethylene, 698 
 Diphenylene diselenide, 215 
 
 Disulphide, 209, 214 
 
 Diphenylene-glycollic Acid, 692, 700 . 
 Diphenylene-iodonium Iodide, 552 
 Diphenylene-ketene, 700 
 Diphenylene-ketone, 692, 699 
 Diphenylene-ketone-carboxylic Acids, 700 
 Diphenylene-methane, 695, 696 
 Diphenylene Oxide, 186 
 Diphenylene-phenanthrene, 699 
 Diphenylene-phenanthrone, 698 
 Diphenylene-phenyl-carbinol, 697 
 Diphenylene-phenyl-methane, 697 
 Diphenylene Sulphide, 210 
 Diphenylin, 147 
 Diphthalide Ether, 351 
 Diphthalyl, 621 
 Diphthalylic Acid, 620 
 Diprotp-catechuic Acid, 337 
 Dipterix odorata, 428 
 Diquinoyl-dioxime, 216 
 Disah'cylide, 331 
 
 Dis-diazo-amido-compounds, 132 
 Dis-diazo-benzol-amide, 135 
 Dis-diazo-benzol-anilide, 135 
 Dis-diazo-benzol-ethyl-amine, 136 
 Dis-diazo-benzol-methyl-amine, 136 
 Disodium Salicylate, 192 
 Disuberyl, 23 
 
 Disulpho-benzoic Acid, 314 
 Disulphones, 181 
 Disulphoxides, 180 
 Ditetramethylene-ketone, n 
 Dithio-aniline, 209 
 Dithio-benzoic Acid, 280 
 Dithio-diphenyl-phthaHde, 596 
 Dithio-diphthalyl, 621 
 Dithio-hydroquinone, 220 
 Dithio-malon-anilide, 108 
 Dithio-oxanih'de, 108 
 Dithio-sah'cylic Acid, 332 
 Ditoluol-sulpho-hydroxamic Acid, 175 
 Ditolyl-amines, 91 
 Ditolyl-disulphone, 181 
 Ditolyl Ketone, 568 
 Divinyl-benzol, 408 
 Dixylylene Disulphide, 344 
 Doebner, 584 
 
 Dryobalanops camphora, 526 
 Duridin, 86 
 Durol, 55, 58 
 Durrhin, 723 
 Dypnone, 629 
 Dypnone-hydroxylamine, 629 
 
 ELEMICIN, 412 
 Ellagic Acid, 341 
 Emeraldin, 237 
 Emodin, 724 
 Emulsin, 720 
 Eosin, 600 
 
 Ephedra vulgaris, 369 
 Ephedrin, 369 
 Eriodictyol, 629 
 Erlenmeyer, E., 382 
 
 Sen., 123 
 
 Erythrin ; 339 
 Erythrinic Acid, 339 
 Erythro-oxy-anthraquinone, 714 
 Erythrol Tetrabenzoate, 278 
 Erythrosin, 600 
 Estragol, 409 
 Ethene-pyrocatechin, 213 
 Ethenyl-phenyl-hydrazin, 163 
 Ethine-diphthalyl, 637 
 Ethoxy-benzaldoxime, 322 
 
742 
 
 INDEX 
 
 Ethoxy-benzo-thiazol, 101 
 Ethoxy-cinnamic Ester, 436 
 Ethoxycumarin, 437 
 Ethoxy-cyanamino-benzoyl, 305 
 Ethoxy-methylene-aniline, 95, 253 
 Ethoxy-mustard Oil, 101 
 Ethoxy-phthalide, 351 
 Ethyl-acetanilide, 95 
 Ethyl-amido-cinnamic Acid, 423 
 Ethyl-aniline, 89 
 Ethyl-anthranilic Acid, 306 
 Ethyl-anthranol-ethyl E'ther, 706 
 Ethyl-benzoic Acids, 274 
 Ethyl-benzol, 30, 55, 57 
 Ethyl-campho-carboxylic Ethyl Ester, 535 
 Ethyl-camphor, 536 
 Ethyl-chavicol, 409 
 Ethyl Chloride, 64 
 Ethyl-diphenyl-iso-urea, 100 
 Ethyl Ester. 99 
 Ethyl-fluorene, 700 
 Ethyl-gallic Ester, 341 
 Ethyl Iso-formanilide, 95 
 Ethyl-iso-thio-acetanilide, 96 
 Ethyl-ketpne, n 
 Ethyl-mesitylene, 59 
 Ethyl-methyl Ester, 101 
 Ethyl Ortho-benzpate, 297 
 Ethyl-orthobenzoic Ester, 297 
 Ethyl-phenols, 188 
 Ethyl-phenyl-dithio-urethane, 101 
 Ethyl-phenyl Ether, 190 
 Ethyl-phenyl-hydrazin, 151 
 Ethyl-phenyl-iso-urea, 100 
 Ethyl-phenyl-methyl-iso-urea, 100 
 Ethyl-phenyl-oxalic Ester, 193 
 Ethyl-phenyl Urea, 99 
 Ethyl-pseudo-cumol, 59 
 Ethyl-phthalide, 349 
 Ethyl-stilbene, 611 
 Ethyl-suberane, 23 
 Ethyl-toluol, 57 
 Ethylene-carbanilide, 100 
 Ethylene-diphenyl-diamine, 90 
 Ethylene-diphenyl-disulphone, 182 
 Ethylene-monophenyl-diamine, 90 
 Ethylene-phenyl-hydrazin, 152 
 Ethylene-phenyl-urea, 100 
 Ethylene-succinic Acid, 162 
 Ethylidene-aniline, 91 
 Ethylidene-camphor, 536 
 Ethylidene Chloride, 64 
 Ethylidene-cyclopentane, 15 
 Ethylidene-dibenzamide, 282 
 Ethylidene-diphenyl-diamine, 90 
 Ethylidene-phthalide, 434 
 Ethylidene-propionic Acid, 47 
 Eucalyptol, 499 
 Eucalyptus, 212 
 Eucalyptus amygdalina, 494 
 
 globulus, 520 
 
 maculata, 489 
 
 Eucarvpne, 25, 514 
 Euchroic Acid, 367 
 Eugenia caryophyllata, 411 
 
 pimenta, 411 
 
 Eugenic Acid, 411 
 Eugenol, 368, 411 
 Eugenol-methyl Ether, 411 
 Eupatorium ayapana, 219 
 Eupitton, 594 
 Eupit tonic Acid, 594 
 Eurhodins, 144 
 Euthio-chronate, 219 
 Euxanthic Acid, 725 
 Evernia prunastris, 339 
 Everninic Acid, 339 
 Exalgin, 95 
 
 FARADAY, 50 
 
 Fatty Acid Derivatives, 157 
 
 Aromatic Sulphides, 210 
 Fehling's Solution, 149 
 Fenchelylamine, 529 
 Fenchene, 525, 520 
 Fenchenol, 528 
 
 Fencholenamine, 529 
 Fenchone, 58, 545 
 Fenchyl Acetate, 528 
 
 Alcohol, 528, 529 
 Bromide, 528 
 
 Chlorides, 528 
 Fenchylamine, 529 
 Ferulic Acid, 430 
 Fichtelite, 693 
 Ficus elastica, 549 
 Fischer, 149, 584. 586, 719 
 Fisetol-dimethyl Ether, 726 
 Fittig, 52, 418 
 Flavanilin, 95 
 Flavanthrene, 711 
 Flaveanic Hydride, 164 
 Flavo-phenin, 555 
 Flavo-purpurin, 717 
 Fluo-nitro-benzoic Acid, 299 
 Fluorane, 598, 599 
 Fluoranthene, 50, 701 
 Fluoranthoquinone, 701 
 Fluorene. 27, 50, 650, 695, 696 
 
 Alcohol, 692, 699 
 
 Fluorene-carboxylic Acid, 700 
 Fluorene Group, 695 
 Fluorene-oxalic Acid, 700 
 
 Ester, 696 
 
 Fluorenol, 699 
 Fluorenone, 699 
 Fluorenone-oxime, 696 
 Fluoresceins, 599 
 Fluorescem-anilide, 600 
 Fluoresce'in-carboxyl-methyl Ester, 600 
 Fluorescei'n-phenyl-hydrazide, 600 
 Fluorescine, 595 
 
 Fluoro-benzols, 60, 6 1 
 Fluoro-naphthalenes, 658 
 Fluoro-toluol, 65 
 Formaldehyde-aniline, 89 
 Formaldehyde-dianthranilic Acid, 306 
 Formamidine-benzo-hydryl, 565 
 Formanilide, 94, 97 
 Formazyl, 142 
 Formazyl-acrylic Acid, 166 
 Formazyl-azo-benzol, 166 
 Formazyl-benzol, 292 
 Formazyl-carboxylic Acid, 166 
 Formazyl Compounds, 163, 165 
 
 Derivatives, 157 
 
 Formazyl-glyoxalic Acid, 166 
 Formazyl Hydride, 166 
 Formazyl-methyl Ketone, 166 
 Formyl Acetanilide, 95 
 Formyl-acetic Ester, 43 
 Formyl-aceto-phenone, 374 
 Formyl-acetone, 43 
 Formyl-amido-phenol, 200 
 Formyl-anthranilic Acid, 302 
 Formyl-benzamide, 281 
 Formyl-camphpr, 536 
 Formyl-hippuric Ester, 283 
 Formyl-phenyl-glycin, 98 
 Formyl-phenyl-hydrazide, 157 
 Formyl-phenyl-hydroxylamine, 78 
 Formyl-propionic Acid, 43 
 Frangulin, 717, 724 
 Fraxetin, 431 
 Fraxin, 721 
 Fraxinus excelsior, 721 
 Friedel, 52 
 Fuchsine, 584 
 
 Fuchsine-sulphurous Acid, 585 
 Fuchsone, 591 
 Fulvenes, 15 
 Furazane, 233 
 
 Galipea officinalis, 547 
 Galipene, 547 
 Gall-aceto-phenone, 327 
 Gallanol, 341 
 Gallem, 601 
 Gallic Acid. 340 
 Gallic-acid Anilide 341 
 GaUic Aldehyde, 325 
 Gallo-bromol, 341 
 
INDEX 
 
 743 
 
 Gallo-carboxylic Acid, 363 
 Galloflavin, 341 
 Gallo-tannic Acid, 342 
 Gallyl-galHc Acid, 343 
 Garancin, 714 
 Garden, 650 
 Garlic, Oil of, 408 
 Gaultherase, 721 
 Gaultheria, 721 
 
 Gaultheria procumbens, 328, 330 
 Gaultherin, 721 
 Gem, 721 
 
 Gelsemium sempervirens, 721 
 Gentisin, 725 
 Gentisin-aldehyde, 325 
 Gentisinic Acid, 339 
 Geranic Acid, 490 
 Geranial, 490 
 Geraniol, 42, 488 
 Geraniolene, 449 
 Gibson, 74 
 
 Glucose-cumaraldehyde, 72 1 
 Glucose Pentabenzoate, 278 
 Glucosides, 221, 719 
 Glutaconic Acid Ester, 43 
 Glycerine-monophenyl Ether, 190 
 Glycerol Tribenzoate, 278 
 Glyco-vanillin, 721 
 Glycocoll, 177 
 Glycol-chloro-hydrin, 684 
 Glycol Dibenzoate, 278 
 Glycol-diphenyl Ether, 190 
 Glycol-monophenyl Ether, 190 
 Glycol-phenyl-urea, 100 
 Glycosides, 719 
 Glyoxal- dipyrocatechin, 213 
 Glyoxalins, 116 
 Glyoxime-N-phenyl-ether, 107 
 Gorgonia Carolinii, 382 
 Graebe, 586, 714 
 Griess, 123 
 Guaiacol, 212 
 
 Guaiacol-sulphonic Acids, 213 
 Gum Lac, 548 
 
 ILEMATEIN-AMMONIA, 726 
 
 Haematin, 726 
 Haematoxylin, 726 
 Hcematoxylon campeckianum, 726 
 Halogen Benzoic Acids, 297 
 
 Diphenyls, 551 
 
 Hydrins, 368 
 
 Phenanthrenes, 689 
 
 Haloid Anhydrides of the Aromatic Acids, 278 
 
 Cinnamic Acids, 421 
 
 Nitro-phenols, 198 
 
 Hantzsch, 124, 250 
 
 Hedeoma pulegioides, 505, 507 
 
 Helianthin, 115 
 
 Helicin, 322, 720, 721 
 
 Heliotropine, 324 
 
 Hemi-mellitic Acid, 365 
 
 Hemimellithol, 55, 57 
 
 Heptacarbocyclic Compounds, 22 
 
 Heptachloro-resorcin, 48, 215, 460 
 
 Heptamethylene, i, 3, 23 
 
 Heptamethylene-terpene, 23 
 
 Heptanaphthene, 446 
 
 Heptyl-benzol, 60 
 
 Hesperetol, 410 
 
 Hesperidene, 491 
 
 Hesperidin, 221, 723 
 
 Hesperitin, 628 
 
 Hetero-ring Formations in Formazyl Compounds, 
 
 166 
 
 Hexa-bromo-cyclo-butane, 1 1 
 Hexa-bromo-triketo-cyclo-hexane, 461 
 Hexa-carbocyclic Compounds, 27 
 Hexa-chloro-a-oxy-cyclopentene-carboxylic Acid, 
 
 20 
 
 Hexa-chloro-benzol, 61 
 Hexa-chloro-cyclopentenones, 18 
 Hexa-chloro-keto-R-pentene, 47 
 Hexa-chloro-diketo-R-hexene, 47 
 Hexa-chloro-p-diketo-R-hexene, 47 
 Hexa-chloro-R-pentene-oxy-carboxylic Acid, 47 
 
 Hexa-chloro- [i, 3, 5]-triketo-R-hexylene, 48 
 Hexa-ethyl-benzol, 55, 57 
 Hexa-hydro-aceto-phenone, 467 
 Hexa-hydro-benzaldehyde, 466 
 Hexa-hydro-benzoic Acids, 470 
 Hexa-hydro-benzols, 444. 445 
 Hexa-hydro-benzyl-amine, 456 
 Hexa-hydro-carvacrol, 452 
 Hexa-hydro-cymol, 497 
 Hexa-hydro-dicarboxylic Acids, 477 
 Hexa-hydro-dioxy-benzoic Acid, 474 
 Hexa-hydro-diphenyl, 550 
 Hexa-hydro-fluorene, 696 
 Hexa-hydro-iso-phthalic Acids, 478 
 Hexa-hydro-mandelic Acid, 475 
 Hexa-hydro-oxy-benzoic Acids. 473 
 Hexa-hydro-oxy-phenyl Fatty Acids, 474 
 Hexa-hydro-phenol, 452 
 Hexa-hydro-phenyl-acetic Acid, 472 
 Hexa-hydro-phenyl-propiolic Acid, 473 
 Hexa-hydro-phenyl-propionic Acid, 472 
 Hexa-hydro-phenyl-tetrolic Acid, 473 
 Hexa-hydro-phthalic Acids, 477 
 Hexa-hydro-propio-phenone, 468 
 Hexa-hydro-pseudo-cumol, 446 
 Hexa-hydro-salicylic Acid, 473 
 Hexa-hydro-terephthalic Acids, 478 
 Hexa-hydro-tetraoxy-benzoic Acid, 474 
 Hexa-hydro-thio-phenol, 455 
 Hexa-hydro-thymol, 452 
 Hexa-hydro-toluol, 446 
 Hexa-iodo-benzol, 62 
 Hexa-methoxy-aurin, 594 
 Hexa-methoxy-benzile, 619 
 Hexa-methoxy-benzilic Acid, 607 
 Hexa-methyl-benzol, 59 
 Hexa-methyl-benzol, 55, 59 
 Hexa-methyl-p-leukaniline, 90 
 Hexa-methyl-para-rosanilin, 587 
 Hexa-methyl-triamido-triphenyl-carbinol, 588 
 Hexa-methyl-triamido-triphenyl-methane, 588 
 Hexa-methylene, i, 3, 13, 445 
 Hexa-methylene-carboxylic Acids, 470 
 Hexa-methylene-tetracarboxylic Acid, 484 
 Hexa-nitro-diphenyl-amine, 112 
 Hexa-m'tro-hydrazo-benzol, 146 
 Hexa-oxy-benzene, 224 
 Hexa-oxy-biphenyls, 557 
 Hexa-phenyl-ethane, 626 
 Hexa-phenyl-melamine, 107 
 Hexyl Iodide, 42 
 Hipparaffin, 282 
 Hippenyl-urethane, 284 
 Hippurazide, 284 
 Hippuric Acid, 282 
 
 Nitrile, 283 
 
 Hippuryl-phenyl-buzylene, 168 
 Hlasiwetz, 221 
 Hoff, Van, 477 
 Hofmann, 50, 145, 585 
 Homo-benzoylated Paraffins, 268 
 Homo-caffeic Acid, 430 
 Homo-camphoric Acid, 544 
 Homo-erio-dictyol, 628 
 Homo-ferulic Acid, 430 
 Homo Gentisinic Acid, 340 
 Homo-iso-phthalic Acid, 364 
 Homo-linaloof, 489 
 Homo-phthaumide, 363 
 Homo-piperonal, 325 
 Homo-piperonyl Alcohol, 321 
 Homo-proto-catechuic Acid, 339 
 Homo-pyrocatechol, 214 
 Homo-saligenin, 316 
 Homo-tanacetone-dicarboxylic Acid, 310 
 Homo-terephthalic Acid, 364 
 Homo-terpenylic Acid, 517 
 Homo-veratric Acid, 340 
 Homologous Anthraquinones, 710 
 Cinnamic Acids, 424 
 
 Iso-phthalic Acids, 360 
 
 Monoxy-benzaldehydes, 323 
 
 Olefin-benzols, 406 
 
 Phenols, 186 
 
 Phenyl-glyoxylic Acids, 390 
 
 Pyrocatechols, 214 
 
744 
 
 Homologues of Benzoic Acid, 274 
 Hordenin, 316 
 Hubner, 32 
 Hydra-benzile, 616 
 Hydracrylic Acids, 383 
 Hydrastic Acid, 359 
 Hydrate de Ph6nyle, 186 
 Hydratropic Acid, 276 
 
 Hydratropic Nitrile, 287 
 Hydrazi-dicarbon-anilide, 101 
 
 Hydrazidins, 163, 291 
 
 Hydrazidoximes, 296 
 
 Hydrazins, 123 
 
 Hydrazin-benzoic Acids, 312 
 
 Lactazame, 312 
 
 Hydrazin-cinnamic Acid, 423, 424 
 
 Hydrazin Compounds, 145 
 
 Hydrazin-salicylic Acid, 333 
 
 Hydrazino-diphenyl, 556 
 
 Hydrazo-benzoic Acid, 312 
 
 Hydrazo-benzol, 69, 145, 146 
 
 Hydrazo-benzol-m-disulphonic Acid, 179 
 
 Hydrazo-compounds, 145 
 
 Hydrazo-naphthalene. 663 
 
 Hydrazo-naphthalin, 663 
 
 Hydrazo-phenols, 206 
 
 Hydrazo-toluene, 147 
 
 Hydrazo-toluols, 146 
 
 Hydrazo-triphenyl-methane, 581 
 
 Hydrazo-xylols, 146 
 
 Hydrazoic Acid, 284 
 
 Hydrazones, 266 
 
 Hydrazoximes, 153 
 
 Hydrindamine, 647 
 
 Hydrindene, 647 
 
 Hydrindene Derivatives, 647 
 
 Hydrindic Acid, 378 
 
 Hydrindone, 647, 648 
 
 Hydrindone-azine, 647 
 
 Hydro-anthracenes, 708 
 
 Hydro-aromatic Aldehydes, 466 
 
 Carboxylic Acids, 469 
 
 Dicarboxylic Acids, 477 
 
 Hydrocarbons, 443 
 
 Ketones, 467 
 
 Monocarboxylic Acids, 469 
 
 Substances, 2 
 
 Hydro-benzamide, 257 
 Hydro-benzoin, 254, 614 
 Hydro-benzol Derivatives, 443 
 Hydro-benzol-tetracarboxylic Acids, 484 
 Hydro-benzol-tricarboxylic Acids 483 
 Hydro-caffeiic Acid, 340 
 Hydro-carbo-styrile, 311 
 Hydro-cinnamic Acid, 276 
 
 Aldehyde, 256 
 
 Azide, 284 
 
 Hydrazide, 284 
 
 Nitrile, 286 
 
 Hydro-cinnamide, 415 
 Hydro-cinnamoin, 640 
 Hydro-cinnamyl Alcohol, 242 
 Hydro-coerulignone, 557 
 Hydro-cornicularic Acid, 637 
 Hydro-cotom, 573 
 Hydro-cumaric Acids, 336 
 Hydro-cumarilic Acid 381 
 Hydro-cumarin, 336 
 Hydro-dicamphene. 525 
 Hydro-diphthalyl-lactonic Acid, 621 
 Hydro-fluoranic Acid 595 
 Hydro- juglones, 671 
 Hydrolytic Condensation, 44 
 Hydro-naphthalene Derivatives, 683 
 Hydro-naphtho-quinone, 670 
 Hydro-p-xylo-quinone, 219 
 Hydro-phenanthrenes, 691 
 Hydro-phlorone, 219 
 Hydro-phthalide, 345 
 Hydro-pinene-carboxylic Acid, 535 
 Hydro-piperic Acid, 430 
 Hydro-quinone, 35 
 Hydro-quinone-benzein, 592 
 Hydro-quinone-carboxylic Acid, 339 
 Hydro-quinone Diacetate, 218 
 Dibenzoate, 219 
 
 INDEX 
 
 Hydro-quinone Disulphide, 223 
 
 Lactic Acid, 381 
 
 Hydro-quinone-monomethyl Ether, 218 
 Hydro-quinone-phenyl-phthalide, 596 
 Hydro-quinone-phthalem, 601 
 Hydro-quinone-propionic Acid, 340 
 Hydro-quinone-succinein, 599 
 Hydro-terpenes, 496 
 Hydro-tetrazones, 167 
 Hydro-tropilidene, 23 
 Hydro-umbellic Acid, 340 
 Hydroxamic Acids, 254 
 
 Their Ethers and Esters, 292 
 
 Hydroxamoximes, 297 
 Hydroxime-acid Chlorides, 292 
 Hydroxy-campho-carboxylic Acid, 544 
 Hydroxylamino-anthraquinones, 710 
 Hydroxylamino-benzaldehyde, 262 
 Hydroxylamino-benzaldoxime, 262 
 Hydroxylamino-benzyl-alcohol, 250 
 Hydroxylamino-carboxylic Acids, 300 
 Hydroxylamino-carvoxime, 510 
 Hydroxylamino-hydro-cinnamic Acid, 383 
 Hyssopus officinalis, 521 
 Hystazarin, 715 
 Hystazarine, 212 
 
 Illicium anisatum, 410 
 
 religiosum, 337, 4", 474 
 
 Imidazols, 116 
 
 Imide, 98 
 
 Imido-benzoyl-cyano-methane, 392 
 
 Imido-chlorides, 287 
 
 Imido-dibenzyl, 610 
 
 Imido-oxy-naphthalene-sulphonic Acid, 670 
 
 Imido-phenyl-carbaminic Thio-methyl Ester, 102 
 
 Immo-benzo-phenone, 569 
 
 Imino-2-cyano-cyclopentane, 22 
 
 Imino-3-cyano-cyclopentane-i-carboxylic Ester, 22 
 
 Indacene, 650 
 
 Indamines, 238 
 
 Indanone. 647, 648 
 
 Indanthrene, 711 
 
 Indene, 27 
 
 Indene-carboxylic Acid, 646 
 
 Indene Derivatives, 645 
 
 Indene-oxalic Ethyl Ester, 646 
 
 Indiazonoxime, 263 
 
 Indigo, 95, 98 
 
 Indo-amine, 117 
 
 Indo-anilines, 236 
 
 Indo-phenols, 117, 236, 239, 676 
 
 Indols, 155 
 
 Indone-acetic Acid, 441 
 
 Indoxyl, 98, 308 
 
 Indoxylic Acid Esters, 307 
 
 Indulins, 144, 238 
 
 Inosite, 453, 454 
 
 Intramolecular Aceto-acetic Ester Condensation, 4 
 
 Pinacone Formation, 4 
 
 [odaceto-phenone, 268 
 
 [odide Chlorides, 61 
 
 todo-aceto-phenone, 372 
 
 lodo-anthraquinone, 710 
 
 todo-benzoic Acids, 298 
 
 [odo-benzols, 61, 62 
 
 todo-camphor, 532 
 
 'odo-chloride-benzol Sulpho-chloride, 177 
 
 iodo-cinnamic Acid. 422 
 
 :odo-diphenacyl, 634 
 
 'odogorgic Acid, 382 
 
 ^odo-hydrin, 369 
 
 iodo-naphthalene, 659 
 
 :odo-o-phthalic Acids, 358 
 
 odo-oxy-naphtho-quinone, 673 
 
 odo-phenyl-hydrazin, 150 
 
 odo-propionic Ester, 98 
 
 odo-salicylic Acid, 333 
 
 odo-toluol, 65 
 
 odoso, 298 
 
 odoso-benzol, 61 
 
 odoso-benzol-sulphonic Acid, 177 
 
 odoso-naphthalenes, 659 
 
 onone, 468 
 
 retol, 223, 722 
 
 ridic Acid, 342, 722 
 
INDEX 
 
 745 
 
 Iridin, 722 
 
 Iridol, 722 
 
 Irigenin, 223 
 
 Iris florentina, 468, 722 
 
 germanica, 468 
 
 pallida, 468 
 
 Irodol, 221 
 
 Irone, 468 
 
 Isapiol, 223 
 
 Isatin, 389 
 
 Isatin-diphthalyl, 649 
 
 Isatinic Acid, 389 
 
 Isatoic Anhydride, 305, 308 
 
 Dialkyl Ester, 304 
 
 Isatropic Acids, 425 
 Iso-allyl -benzol, 406 
 Iso-amenyl-benzol, 407 
 Iso-amino-camphor, 539 
 Iso-amyl Ether, 190 
 Iso-anthraflavic Acid, 716 
 Iso-benzile, 619 
 Iso-borneol, 527 
 Iso-borneol Acetate, 522 
 Iso-butyl-alk., 82 
 Iso-butyl-benzol, 59 
 Iso-butyl-mesitylene, 59 
 Iso-campholic Acid, 537 
 Iso-camphoric Acid, 541 
 Iso-camphoronic Acid, 517, 538 
 Iso-capro-lactpne, 518 
 Iso-carbo-styril, 435 
 Iso-cumarin, 434, 435 
 Iso-cumarin-carboxylic Acid 442 
 Iso-cyano-phenyl-chloride, 97, 105 
 Iso-cyclic Compounds, i 
 Iso-dihydro-lauro-lactone, 542 
 Iso-dihydrp-phene-tetrazins. 144 
 Iso-diphenic Acid, 561 
 Iso-duridin, 86 
 Iso-durol, 55, 58 
 Iso-elemicin, 412 
 Iso-eugenol, 368, 411 
 Iso-eugenpl-methyl Ether, 411 
 Iso-ethindiphtalyl, 719 
 Iso-fencho-camphoric Acid, 546 
 Iso-fencholene Alcohol, 528 
 Iso-fencholic Acid, 546 
 Iso-fenchone, 546 
 Iso-fenchyl Alcohol, 528 
 Iso-ferulic Acid, 430 
 Iso-homo-pyrocatechol, 214 
 Iso-keto-camphoric Acid, 538 
 Iso-laurolene, 543 
 Iso-lauronolic Acid, 542 
 Iso-naphthazarin, 673, 674 
 Iso-naphtho-fluorene, 697 
 Iso-naphtho-fluorenone, 648, 699 
 Iso-nitroso-aceto-phenone, 374 
 Iso-nitroso-camphor, 533 
 Iso-nitroso-hydrindone, 647 
 Iso-orcin, 217 
 
 Iso-oxalyl-dibenzyl-ketone, 636 
 Iso-phenyl-acetic Acids, 24 
 Iso-phorone, 462 
 Iso-photo-santonic Acid, 725 
 Iso-phthalic Acid, 36, 38, 56, 359 
 Iso-prene, 487 
 Iso-propenyl-benzol, 406 
 Iso-propenyl-naphthalin, 658 
 Iso-propyl-benzom, 616 
 Iso-propyl-benzol, 55, 57 
 Iso-propyl-cyclopentane-i, 6-diol, 16 
 Iso-propyl-dihydro-resorcin, 459 
 Iso-propyl-diphenyl. 693 
 Iso-propyl-hexyl-benzol, 60 
 Iso-propyl-idene-cyclopentane, 1 5 
 Iso-propyl-phenol, 188 
 Iso-propylidene-cyclo-hexanone, 462 
 Iso-pulegol, 489 
 Iso-pulegone, 508 
 Iso-purpurin, 717 
 Iso-safrol, 368, 412 
 
 Dibromide. 369 
 
 Iso-thio-cyanic Phenyl Ester, 106 
 Iso-thujone, 513 
 Iso-valerianic Ester, 498 
 
 Iso-vanillic Acid, 338 
 Iso-vanillin, 324 
 Iso-violanthrenes, 719 
 Iso-xylol, 36, 38, 55, 56 
 
 JACKSON, 418 
 Jalapin, 722 
 Jayne, 418 
 Juglpnic Acid. 359 
 Juniperus virginiana, 548 
 
 KEKULE, 2, 27, 29, 123, 443, 586 
 Kermessic Acid, 728 
 Keto-dihydro-naphthoic Acid, 679 
 Keto-dihydro-quinazolins, 308 
 Keto-hexamethylene, 457 
 Keto-hydrazones, 152 
 Keto-hydro-monocarboxylic Acids, 475 
 Keto-iso-camphoric Acid. 517 
 Keto-menthanes, 505 
 Keto-menthenes, 506 
 Keto-pentamethylene, 17 
 Keto-pentamethylene-3-carboxylic Acid, 21 
 Keto-pentamethylene-carboxylic Ester, 21 
 Keto-pentamethylene-2, 3-dicarboxylic Ester, 21 
 Keto-pentamethylene-3, 4-dicarboxylic Acid, 21 
 Keto-phenyl-paraconic Ester, 400 
 Keto-tetramethylene-cyclo-butanone, 1 1 
 Keto-tetramethylene-tricarbo-esters, 12 
 Ketone-aldehydes, 373, 374 
 Ketone-carboxylic Acids, 353, 387. 393 
 Ketone-tricarboxylic Acids, 403 
 Kino. 212 
 Kino-tannin, 343 
 Kohler, 723 
 Kolbe, 334 
 Korner, 31, 32 
 Kynuric Acid, 305 
 
 LACCAINIC Acid, 728 
 
 Lactames, 159 
 
 Ladenburg, 31, 33, 41, 334 
 
 Laevuhnic phenyl-hydrazone, 159 
 
 Laurent, 186, 355 
 
 Laurolene, 543 
 
 Lauronoh'c Acid, 542 
 
 Lead-tetraphenyl, 172 
 
 Lecanium Ilicis, 728 
 
 Lecanora, 217 
 
 Lecanpric Acid, 339 
 
 Lepidium sativum, 286, 720 
 
 Leuco-benzaurin, 590 
 
 Leuco-benzein, 590 
 
 Leuco-malachite Green, 578 
 
 Leuco-rosolic Acid, 590 
 
 Leucaniline, 579 
 
 Leucaurins, 590 
 
 Leuconic Acid, 14, 232 
 
 Lichen Dyes, 727 
 
 Liebermann, 714 
 
 Liebig, 255, 282, 382, 723 
 
 Ligustrum vulgar e, 721 
 
 Limonene, 491 
 
 Linaloolene, 487 
 
 Linalool, 487, 488 
 
 Linamarin, 723 
 
 Lipp, 382 
 
 Lippia ctiriodora, 487 
 
 Liauidambar oriental is, 413 
 
 Litmus, 217 
 
 Loschmidt, 28. 29 
 
 Lupinus luteus, 380 
 
 Luteic Acid, 341 
 
 LuteoUn, 338 
 
 MACI Oil, 412 
 Maclurin, 338, 343, 573 
 Magnesium-diphenyl, 171 
 Malachite Green, 90, 583 
 Maleic Acid, 46 
 Maleino-phenyl-hydrazil, 163 
 Malon-anih'c Acid, 108 
 Malon-anilide, 108 
 Malonic Diphenyl Ester, 193 
 
 Ester Phenyl-hydrazide, 162 
 
 Methyl-anilide,'io8 
 
746 
 
 INDEX 
 
 Malono-phenyl-hydrazilic Ester, 162 
 Malonyl-diphenyl-hydrazide, 162 
 Malonyl-phenyl-hydrazide, 162 
 Manchester Brown, 145 
 Mandelic Acid Nitrile, 377 
 
 Chloralide, 3 77 
 
 Nitrile Glucoside, 723 
 
 Marignac, 355 
 
 Matezite, 454 
 
 Matricaria Parthenium, 530 
 
 Meconin, 349 
 
 Meconin-acetic Acid, 401 
 
 Melanilin, 104 
 
 Melilotic Acid, 336 
 
 Melilotus officinalis, 336, 427, 428 
 
 Mellimide, 366 
 
 Mellithic Acid, 43 
 
 MeUitic Acid, 366 
 
 Mellophanic Acid, 366 
 
 Menaphthyl-amines, 677 
 
 Mentha pulegium, 507 
 
 Menthadiene, 495 
 
 Alcohols, 503 
 
 Menthadiene-ketones, 509 
 Menthane, 486, 497 
 Menthene, 449, 496 
 
 Alcohols, 502 
 
 Menthene-glycol, 500 
 Menthenol, 503 
 Mentho-citronellal, 490 
 Mentho-menthene, 496 
 Mentho-naphthene, 497 
 Mentho-nitrile, 506 
 Menthone, 505 
 Menthone-oxime, 506 
 Menthonenic Acid, 506 
 Menthoximic Acid, 505 
 Menthyl Chloride, 498 
 Menthyl-xanthogenic Methyl Ester, 498 
 Menthylamine, 504 
 Mercaptans, 208 
 Mercuri-nitro-phenols, 196 
 Mercurio-acetanilide, 95 
 Mercury-dialphyls, 172 
 Mercury-diphenyl, 171 
 Mercury Phenate, 186 
 Mercury-phenyl Acetate, 172 
 
 Bromide, 172 
 
 Chloride, 172 
 
 Hydroxide, 172 
 
 Iodide, 172 
 
 Mercury Thio-phenate, 208 
 Mesicerine, 345 
 Mesidic Acid, 360 
 Mesidin, 86 
 
 Mesidin-iodo-hydrate, 82 
 Mesitol, 188 
 
 Mesityl-hydroxylamine, 78 
 Mesityl-iso-phthalic Acid, 361 
 Mesityl-quinol, 320 
 Mesitylene, 33, 55> 56, 57 
 Mesitylene-glycerin, 345 
 Mesitylene-sulphonic Acid, 175 
 Mesitylene-trialdehyde, 346 
 Mesitylenic Acid, 31, 38. 56, 57 
 Meso-amido-anthracene, 705 
 Meso-benzo-dianthrone, 718 
 Meso-dihydro-dianthrone, 706 
 Meso-naphtho-dianthrone, 718 
 Meso-phenyl-anthramine, 705 
 Meso-phenyl-anthrone, 707 
 Meso-xanil-amido-chloride, 97 
 Mesorcin. 217 
 
 Meta-bromo-benzoic Acid. 32 
 Meta-dinitro-benzol, 70 
 Meta-hemi-pinic Acid, 359 
 Meta-oxy-benzoic Acid, 31, 36 
 Meta-phenol-sulphonic Acid, 207 
 Metanil Yellow, 179 
 Methane, 42 
 
 Methene-cyclp-hexane, 449 
 Methenyl-amido-thio-phenol, 105 
 Methenyl-diphenyl-diamine, 96 
 Metho-vinyl-benzol, 406 
 Methoxy-benzyl Alcohol, 316 
 Methoxy-cinnamic Acid, 427 
 
 Methoxy Aldehyde, 415 
 
 Ester, 436 
 
 Methoxy-hydratropa-aldehyde, 323 
 
 Methoxy-phenanthrene, 690 
 
 Methoxy-phenanthrene-g-carboxylic Acid. 691 
 
 Methoxy-phenyl-acetaldehyde, 323 
 
 Methoxy-phthalide, 351 
 
 Methoxy-salicylic Acid, 726 
 
 Methoxyl-coniferin, 721 
 
 Methyl-acetanilide, 95 
 
 Methyl-2 -acetyl- A 1 -cyclopentene, 1 9 
 
 Methyl-2 -acetyl -pentamethylene, 1 9 
 
 Methyl-i -acetyl-pentamethylene-carboxylic Acid, 
 
 22 
 
 Methyl-aesculetin, 431 
 
 Methyl-alizarin, 716 
 
 Methyl- a-amido-cyclopentane-carboxylic Acid, 21 
 
 Methyl-amido-phenol 200 
 
 Methyl-aniline, 89 
 
 Methyl-anthracene, 704 
 
 Methyl-anthranile, 303 
 
 Methyl-anthranilic Acid, 306 
 
 Methyl-anthranilido-acetic Acid, 308 
 
 Methyl-anthraquinone, 710 
 
 Methyl-anthrone, 707 
 
 Methyl Arbutin, 720 
 
 Methyl-atropic Acid, 426 
 
 Methyl-benzimido-chloride, 287 
 
 Methyl-benzoic Acids, 274 
 
 Methyl-benzoic Ester, 278 
 
 Methyl-benzoin, 616 
 
 Methyl-benzol, 30 
 
 Methyl-benzoyl-acetic Ester, 393 
 
 Methyl-benzyl Cyanides. 286 
 
 Methyl-benzyl-malonic Acid, 396 
 
 Methyl-bromo-camphor, 535 
 
 Methyl-camphenilol, 527 
 
 Methyl-camphor, 535 
 
 Methyl-carbostyrile, 98 
 
 Methyl-cetyl-benzol, 60 
 
 Methyl-chavicol, 409 
 
 Methyl-chloro-stilbene, 619 
 
 Methyl Chloroform, 64 
 
 Methyl-cinnamic Acid, 424 
 
 Aldehyde, 415 
 Methyl-cumarilic Ester, 191 
 Methyl-cumarin, 429 
 Methyl-cyclo-hexadiene-acetic Acid, 473 
 Methyl-cyclo-hexane, 446 
 Methyl-cyclo-hexanol, 452 
 Methyl-cyclo-hexanol-acetic Acid, 474 
 Methyl-cyclo-hexanone, 458 
 Methyl-cyclo-hexenes, 448 
 Methyl-cyclo-pentadiene-carboxyl-propionic Acid, 
 
 20 
 
 Methyl-cyclo-pentane-carboxylic Acid, 19, 20 
 Methyl-cyclo-pentanol, 16 
 Methyl- 1, i -cyclo-pentanol-acetic Ester, 21 
 Methyl-cyclo-pentanone, 17 
 Methyl-cyclo-pentene, 14 
 Methyl-cyclo-pentene-acetic Acid, 20 
 Methyl-cyclo-pentenone, 17 
 Methyl-cyclo-propene-dicarboxylic Acid, 10 
 Methyl-diketo-hydrindene, 649 
 Methyl-diphenylamine, 92 
 Methyl-ditolyl-iso-urea, 100 
 Methyl Ester, 99 
 
 Ether, 536 
 
 Methyl-ethyl-aniline, 90 
 Methyl-ethyl-aniline Oxide, 90 
 Methyl-ethyl-cyclopentane, 14 
 Methyl-ethyl-fulvene, 15 
 Methyl-ethyl-ketone, 42 
 Methyl-fluorene, 700 
 Methyl Formanilide, 94 
 Methyl-formazy], 166 
 Methyl-gluco-o-cumar-ketouC; 721 
 Methyl-glyoxal-phenyl-hydrazoxime. 153 
 Methyl Green, 588 
 Methyl-heptenone, 489 
 Methyl-hexahydro-fluorene, 697 
 Methyl-hexanitro-diphenyl-amine, 112 
 Methyl-hydrocotom. 573 
 Methyl-hystazarin, 716 
 Methyl-indene. 645 
 Methyl-iridic Acid, 342 
 
INDEX 
 
 747 
 
 Methyl-isatin, 390 
 Methyl-iso-cumarin, 435 
 Methyl iso-formanilide, 95 
 Methyl-iso-propyl-benzol. 58 
 Methyl-iso-propyl-cyclo-hexane, 446 
 Methyl-iso-propyl-phenanthraquinone, 693 
 Methyl-iso-thio-acetanilide, 96 
 Methyl-3-methylene-cyclopentane, 15 
 Methyl-morphol, 690 
 Methyl-n-propyl-ketone, 42 
 Methyl-naphtho-quinitrol, 666 
 Methyl-naphtho-quinol, 666 
 Methyl-naphthol, 666 
 Methyl-nopinol, 520 
 
 Methyl-nor-caradiene-carboxylic Ester, 641 
 Methyl-nor-opianic Acid, 352 
 Methyl-opianic Ester, 352 
 Methyl-p-norm.-propyl-phenol, 189 
 Methyl -pentamethylene, 14 
 Methyl-phenanthrene, 689 
 Methyl-phenyl-cyano-triazene, 136 
 Methyl-phenyl Ether, 190 
 Methyl-phenyl-glycin, 98 
 Methyl-phenyl-glycocoll-methyl Ester, 98 
 Methyl-phenyl-hydrazin, 119, 151 
 Methyl-phenyl-iso-urea, 100 
 Methyl -phenyl-nitro-amine, 119 
 Methyl-phenyl -nitrosamine, 119 
 Methyl-phenyl-thio-carbamine Chloride, 101 
 Methyl-phenyl-triazene, 135 
 Methyl-phenyl-urea Chloride, 9 
 Methyl-phthalazone, 353 
 Methyl-purpuro-xanthins, 716 
 Methyl-sabina-ketol, 511 
 Methyl-salicyl Chloride, 33^ 
 Methyl-sinapinic Acid, 431 
 Methyl -stilbene, 611 
 Methyl-suberene, 23 
 Methyl-suberenone, 24 
 Methyl-suberol, 23 
 Methyl-sulphonic Phenyl Ester 191 
 Methyl- tert. -butyl -benzol, 59 
 Methyl-tetramethylene, 10 
 Methyl-thio-acetanilide, 96 
 Methyl-thio-benzamide, 289 
 Methyl-thio-salicylic Acid, 332 
 Methyl-triketo-pentamethylene, 18 
 Methyl-trimethylene, 7 
 Methyl-triphenyl-methane, 577 
 Methyl-umbelliferone, 430 
 Methyl-vanillin, 324 
 Methyl Violet, 587, 588 
 Methylene-anthranilic Acid, 307 
 Methylene-bis-hydro-resorcin, 565 
 Methylene Blue, 115 
 Methylene-camphor, 535 
 Methylene-cyclopentane, 14, 23 
 Methylene-dianthranilic Acid, 306 
 Methylene-dibenzamide, 282 
 Methylene Dibenzoate, 278 
 Methylene-diorcin, 565 
 Methylene-diphenyl-diamine, 90 
 Methylene-diphloro-glucin, 565 
 Methylene-diresorcin, 565 
 Methylene-phthah'de, 434 
 Methylene-proto-catechuic Acid, 338 
 Methylene-quinones, 317, 318, 465, 564 
 Meyer, 599 
 
 Mimosa catechu, 212, 343 
 Mitscherlich, 50 
 
 Monacid Menthane Alcohols, 497 
 M onarda punctate, 188 
 Mono-acetyl-hydrazo-benzol, 146 
 Mono-bromo-acetylene, 42 
 Mono-bromo-durol, 66 
 Mono-bromo-isodurol, 66 
 Mono-bromo-mesitylene, 66 
 Mono-bromo-prehnitol, 66 
 Mono-bromo-pseudocumol, 66 
 Mono-bromo-stilbene, 619 
 Mono-chloro-cyclopentene. 15 
 Mono-chloro-quinone, 46 
 Mono-chloro-stilbene, 619 
 Mono-chloro-trimethylene, 7 
 Mono-cyclic Terpenes, 491 
 Mono-haloid Cinnamic Acids, 422 
 
 Mono-haloid Phenols, 194 
 
 Mono-hydric Oxy-phenyl-paraffin Alcohols, 314 
 
 Phenols, 183 
 
 Mono-methyl-aniline, 89 
 Mono-nitro-phenols, 195 
 Mono-nitro-terephthalic Acid, 362 
 Mono-nitroso-naphthalene, 659 
 Mono-nuclear Aromatic Substances, 27 
 Mono-sulphonic Acids, 174 
 Mono-thio-hydroquinone, 220 
 Mono-thio-pyrocatechol, 214 
 Monoxy-alcohol Acids, 376 
 Monoxy-anthracene, 705 
 Monoxy-anthraquinones, 714 
 Monoxy-benzaldehydes, 321 
 Monoxy-benzoic Acids, 328 
 Monoxy-benzyl Alcohols, 315 
 Monoxy-biphenyls, 556 
 Monoxy-monocarboxyh'c Acids, 328 
 Monoxy-naphthacene-quinone, 719 
 Monoxy-phenyl-olefin-carboxylic Acids, 4.26 
 Monoxy-triphenyl-methanes, 589 
 Morin, 343 
 
 Morinda citrifolia, 714,717 
 Morindone, 717 
 Moringa-tannin, 343 
 Morphia, 689 
 Morphol-quinone, 693 
 Moms tinctoria, 338, 343 
 Mustard Oil, 97, 408 
 Myrcene, 487 
 Myristicin, 412 
 Myrtenol, 520 
 
 NAPHTHACENE, 719 
 Naphthacene-di-quinone, 719 
 Naphthacene-quinone, 719 
 Naphthaldehyde, 677 
 Naphthaldehydic Acid, 682 
 Naphthalene, 657 
 
 Naphthalene-dicarboxylic Acid. 680 
 Naphthalene Bichloride 684 
 Naphthalene-disulphonic Acids 663 
 Naphthalene Disulphydrates, 671 
 
 Group, 650 
 
 Red, 662 
 
 Ring, Decompositions of, 654 
 
 Naphthalene-ring Formations, 652 
 Naphthalene-sulphinic Acids, 665 
 Naphthalene-sulphonic Acids, 663 
 Naphthalene Tetrabromide, 685 
 Naphthalene-tetracarboxylic Acid, 680 
 Naphthalene Tetrachloride, 685 
 Naphthalene-trisulphonic Acids, 664 
 Naphthalic Acid, 673, 680 
 Naphthalin, 37, 50 
 NaphthaUn-azo-compounds, 178 
 Naphthaline Homologues, 657 
 NaphthaUzarin, 673 
 Naphthanthracene, 719 
 Naphthanthraquinone, 719 
 Naphthazarin, 673, 714 
 Naphthenes, 444, 445, 470 
 Naphthenic Acid, 470 
 Naphthidin, 663 
 Naphtho-azimides, 661 
 Naphtho-benzyl Alcohols, 676 
 Naphtho-benzyl-amines, 677 
 Naphtho-benzyl Chlorides, 676 
 Naphtho-cumarin, 678 
 Naphtho-fluorenone, 699 
 Naphtho-furazane, 675 
 Naphtho-methylene-quinone, 666 
 Naphtho-nitriles, 68 1 
 Naphtho-purpurin, 673 
 Naphtho-pyrogallol, 671 
 Naphtho-quinones, 668, 671, 672, 673, 674 
 Naphtho-quinone-anile, 676 
 Naphtho-quinone Chlorimides, 675, 676 
 Naphtho-quinone-dichlorimide, 676 
 Naphtho-quinone-dipxime, 675 
 Naphtho-quinone-imides, 676 
 Naphtho-quinone-phenyl-hydrazones, 674 
 Naphtho-quinoximes, 674 
 Naphtho-resorcin-carboxylic Acid, 679 
 Ester, 399 
 
INDEX 
 
 Naphtho-resorcinol, 670 
 Naphtho-stilbene, 68 1 
 Naphtho-styril, 678 
 Naphtho-sultone, 670 
 Naphtho-xanthones, 679 
 Naphthoic Acid, 678 
 Naphthols, 81, 665 
 Naphthol-aldehyde, 677 
 Naphthol-alkyl Ethers, 666 
 Naphthol-azo-benzol, 668 
 Naphthol Blue, 239, 676 
 Naphthol-carboxylic Acids, 678, 679 
 Naphthol-ethyl Ether, 666 
 Naphthol Green, 675 
 
 Homologues, 666 
 
 Naphthol-methyl Ether, 666 
 Naphthol-methyl-ketone, 677 
 Naphthol Orange, 668 
 Naphthol-sulphonic Acids, 668 
 Naphthoxazoles, 667 
 Naphthyl-acetic Acid, 678 
 Naphthyl-acrylic Acids, 678 
 Naphthyl-azo-acetic Ester, 662 
 Naphthyl-benzene Sulphamides, 661 
 Naphthyl-carbinols, 676, 677 
 Naphthyl-dimethylamine, 660 
 Naphthyl-diphenyl-carbinol, 677 
 Naphthyl-ethylamine, 660 
 Naphthyl-hydrazins, 663 
 Naphthyl-iodo-chlorides, 659 
 Naphthyl-iso-crotonic Acid, 688 
 Naphthyl-mercaptan, 671 
 Naphthyl-methyl-acetaldehyde, 677 
 Naphthyl-methyl-ketone, 677 
 Naphthyl-methylamine, 660 
 Naphthyl-nitramine, 662 
 Naphthyl-nitro-methane, 677 
 Naphthyl-phenyl-carbinol, 677 
 Naphthyl-phenyl Ether, 666 
 Naphthylamines, 81, 660 
 Naphthylamine-sulphonic Acids, 664 
 Naphthylenes, 447 
 Naphthylene-diamines, 66 1, 662 
 Naphthylene-dihydrazin, 663 
 Narcotin, 359 
 Naringenin, 628, 723 
 Naringin, 723 
 
 Nasturtium officinale, 286, 720 
 Nerol, 488 
 Neroli Oil, 302 
 Neville, 669 
 Nietzki, 231, 232 
 Nigritella suaveolens, 324 
 Nirvanin, 333 
 
 Nitramino-anthraquinone, 712 
 Nitranilic Acid, 230 
 Nitranilide, 120 
 Nitranilines, no 
 Nitrazones, 163, 164 
 Nitrile Oxides, 295 
 Nitrite, 125 
 
 Nitro-acetaldehydrazone, 165 
 Nitro-aceto-phenones, 268, 372 
 Nitro-alizarin, 715 
 Nitro-anthracene, 704 
 Nitro-anthranilic Acid, 308 
 Nitro-anthraquinones, 710 
 Nitro-anthrone, 705 
 Nitro-azo-benzol, 142 
 Nitro-azoxy-benzol, 140 
 Nitro-benzal-acetone, 416 
 Nitro-benzal-divanillin, 594 
 Nitro-benzaldehydes, 261 
 Nitro-benzene, 29 
 Nitro-benzo-phenones, 570 
 Nitro-benzoic Acids, 298, 299 
 Nitro-benzols, 69, 70 
 Nitro-benzol-azo-p-amido-benzol, 144 
 Nitro-benzoyl-acetic acid, 393 
 Nitro-benzoyl-formic Acid, 388 
 Nitro-benzyl-amine, 251 
 Nitro-benzyl-malonic Ester, 396 
 Nitro-benzyl Sulpho-cyanide, 251 
 Nitro-bromo-durol, 74 
 Nitro-camphane, 532 
 Nitro-camphene. 522 
 
 Nitro-camphor, 532 
 Nitro-chloro-tolu-quinone, 319 
 Nitro-cinnamic Acids, 422, 423 
 Nitro-cinnamic Aldehydes, 415 
 Nitro-cinnamyl-formic Acid, 437 
 Nitro-coccic Acid, 728 
 Nitro-cresols, 197 
 Nitro-cumaric Acid, 427 
 Nitro-cumarinic Acid, 426, 428 
 Nitro-diazo-benzol-imide, 138 
 Nitro-diazo-benzol Methyl Ether, 126 
 Nitro-diazo-benzolic Acid, 120 
 Nitro-dimethyl-aniline, 89 
 Nitro-dioxy-quinone-sulphonic Acid, 231 
 Nitro-diphenic Acid, 561 
 Nitro-diphenyls, 552 
 Nitro-diphenyl-amines, in, 112 
 Nitro-diphenyl-methanes, 563 
 Nitro-diphenyl-sulphone, 183 
 Nitro-fluorene, 696, 697 
 Nitro-fluorenone, 700 
 Nitro-formaldehydrazone, 164 
 Nitro-formazyl, 166 
 Nitro-halogen-benzpls, 71 
 Nitro-haloid Benzoic Acids, 299 
 Nitro-homo-veratrol, 726 
 Nitro-hydran-thranol, 704 
 Nitro-hydratropic Acids, 300 
 Nitro-hydrazones, 157, 164 
 Nitro-hydro-cinnamic Acids, 300 
 Nitro-hydroquinone, 219 
 
 Nitro-hydroxy-dihydro-trimethyl-brasilone, 726 
 Nitro-indene, 645 
 Nitro-m-xylol, 73 
 Nitro-malonic Aldehyde, 43 
 Nitro-mesitylene, 73 
 Nitro-methylene-phthalide, 434 
 Nitro-monocarboxylic Acids, 298 
 Nitro-naphthalenes, 659 
 Nitro-naphthalene-sulphonic Acids, 664 
 Nitro-naphthoic Acids, 678 
 Nitro-naphthols, 666 
 Nitro-naphthylamines, 661 
 Nitro-nitroso-benzol, 76 
 Nitro-o-phthalic Acids, 358 
 Nitro-o-xylol, 73 
 Nitro-opianic Acid, 352 
 Nitro-oxanilic Acid, 108 
 Nitro-oxy-diphenyl, 557 
 Nitro-p-phenylene-diamine, 115 
 Nitro-p-xylol, 73 
 Nitro-pentamethyl-benzol, 74 
 Nitro-phenanthrenes, 689 
 Nitro-phenanthrene-quinone, 692 
 Nitro-phenols, 35, 195 
 Nitro-phenyl-acetic Acids, 300 
 Nitro-phenyl-acetylene, 407 
 Nitro-phenyl-amine, 112 
 Nitro-phenyl-benzaldehyde, 559 
 Nitro-phenyl-diazo-sulphide, 126 
 Nitro-phenyl-diazo-disulphide, 127 
 Nitro-phenyl-diazo-mercaptan Hydrosulphide, 126 
 Nitro-phenyl Ether, 191 
 Nitro-phenyl-glyceric Acid, 385 
 Nitro-phenyl-glycin, 98 
 Nitro-phenyl-hydrazin, 150 
 Nitro-phenyl-hydrazin-disulphonic Acid, 156 
 Nitro-phenyl-hydrazones, 142 
 Nitro-phenyl-hydroxylamine, 78 
 Nitro-phenyl-lactic Acids, 381, 383 
 Nitro-phenyl-propiolic Acid, 432 
 Nitro-phenyl-pyro-racemic Acid, 391 
 Nitro-phthalide, 349 
 Nitro-phthalyl Chloride, 358 
 Nitro-piperonal, 325 
 Nitro-prehnitol, 74 
 Nitro-pseudocumol, 73 
 Nitro-resprcin, 216 
 Nitro-salicylic Acid, 333 
 Nitro-stilbene, 611 
 Nitro-styrols, 405 
 Nitro-terebentene, 519 
 Nitro-thio-phenol, 208 
 Nitro-toluols, 72, 73 
 
 Nitro-triphenyl-carbinol, 582 
 Nitro-xylenols, 198 
 
INDEX 
 
 749 
 
 Xitrolamines, 504 
 Nitrosanilides, 119 
 Nitrosazones, 165 
 Nitroso-acetanilide, 113, 120 
 Xitroso-acetyl-phenyl-hydrazin, 167 
 Nitroso-aniline, 113 
 Xitroso-benzaldehydes, 262 
 Nitroso-benzoic Acid, 261 
 
 Esters, 261 
 
 Nitroso-benzol, 69 
 Nitroso-benzol-sulphonic Acid, 177 
 Nitroso-benzyl Alcohol, 250 
 Xitroso-benzyl-urethane, 248 
 Nitroso-chloride, 15 
 Xitroso-cresol, 199 
 Xitroso-diethyl-aniline, 113 
 Xitroso-dimethyl-aniJine, 89, 113 
 Nitroso-diphenyl-amine, 113 
 Xitroso-diphenyl-hydroxylamine, 79 
 Xitroso-formanilide, 120 
 Nitroso-formyl-phenyl-hydrazin, 167 
 Xitroso-guaiacol, 213 
 Xitroso-m-phenylene-diamine, 114 
 Nitroso-mesitylene, 76 
 Xitroso-methyl-anthranilic Acid, 306 
 Nitroso-monocarboxylic Acids, 300 
 Nitroso-monoethyl-aniline, 113 
 Xitroso-monomethyl-aniline, 113, 119 
 Nitroso-naphthalenes, 659 
 Xitroso-naphthols, 674 
 Xitroso-orcin, 217 
 Xitroso-oxy-diphenyl, 557 
 Nitroso-phenol, 198 
 Nitroso-phenyl-hydrazones, 142 
 Nitroso-phenyl-semicarbazide, 167 
 Xitroso-phenyl-urea, 120 
 Nitrosophthalimidin, 348 
 Nitroso-pinene, 519 
 Nitroso-salicylic Acid, 333 
 Nitroso- thymol, 199 
 Nitroso-toluol, 76 
 Nitroso-xylol, 76 
 Nonocarbbcych'c Compounds, 26 
 Nonomethylene, i, 3 
 Nononaphthene, 446 
 Nopinene, 519 
 Nopinic Acid, 519 
 Nopinol-acetic Acid, 521 
 
 Nopinone, 519, 521 
 Xor-borneol, ^ 
 
 1,526 
 Nor-camphane, 513 
 Nor-caradiene-carboxylic Acid, 25 
 Nor-carane, 513, 641 
 Nor-carane-dicarboxylic Ester, 641 
 Xor-hemi-pinic Acid. 359 
 Xor-opiamc Acid, 352 
 Xor-pinane, 513 
 Xor-pinic Acid, 13, 516 
 Xuclear Synthesis, 51 
 Nutmeg Oil, 412 
 
 O-BENZO-BETA?N, 306 
 o-Cyano-anilic Acid, 305 
 Oak -red, 343 
 Ocimene, 487 
 Octazones, 168 
 
 Octo-carbocyclic Compounds, 25 
 Octo-chloro-acety-facetone, 48 
 Octo-chloro-keto-tetrahydro-benzol, 463 
 Octo-chloro-phenanthrene, 689 
 Octo-decyl-benzol, 60 
 Octo-hydro-carbostyril, 471 
 Octo-hydro-naphthalenes, 687 
 Octo-methylene, i, 3 
 Octo-naphthene, 446 
 Octyl-benzol, 60 
 Oglialoro, 418 
 Oldenlandia umbellata, 715 
 Olefm-acetylene-benzols, 408 
 Olefin-benzenes, 403 
 Olefin-dioxy-benzols, 410 
 Olefin-monoxy-benzols, 409 
 Olefin-phenols, 408 
 Olefin-tetraoxy-benzols, 412 
 Olefin-trioxy -benzols, 412 
 Olefinic Terpene, 487 
 
 Olefinic Terpene Acids, 490 
 
 Terpene-aldehydes, 489 
 
 Oleum cadinum, 547 
 Oleum cina, 499 
 Opianic Acid, 350, 352 
 Opianoximic Acid, 352 
 Orange-blossom Oil, 302 
 Orcin, 216, 217 
 Orcin-aurin, 594 
 Orcin-phthaleins, 601 
 Orcyl-aldehyde, 325 
 Orsellinic Acid, 339 
 Ortho-acetic -phenyl Ester, 192 
 Ortho-benzoic Acid Piperidide, 297 
 
 Derivatives of, 297 
 
 Ortho-dinitro-benzol, 70 
 Ortho-form, 334 
 Ortho-oxy-benzoic Acid, 31 
 Ortho-phosphoric Anilide, 93 
 Ortho-quinones, 225 
 Ortho-silico-benzoic Acid Ester, 170 
 Ortho-xylol, 36 
 Orthrin, 273 
 Osazones, 152 
 Oso-tetrazones, 155 
 Oxal-phenyl-hydrazide, 162 
 Oxal-phenyl-hydrazilic Acid, 162 
 Oxalate, 125 
 
 Oxalo-acetic Ester Condensation, 4 
 Oxalo-diamido-pxime, 164 
 Oxalyl-anthranilic Acid, 305 
 Oxalyl-anthranilic Acid NitrUe, 305 
 Oxalyl-diaceto-phenone, 640 
 Oxalyl-dibenzyl-ketone, 18 
 Oxanile Dichloride Acid Ethyl Ester, 108 
 Oxanilic Acid. 107 
 
 Nitrile, 107 
 
 Thio-amide, 107 
 
 Oxanih'de, 107 
 
 Dioxime, 108 
 
 Oxanthrone, 708, 709 
 Oxatolylic Acid, 631 
 Oxethyl-anisidin. 200 
 Oximido-diphenyl-urea, 104 
 Oximido-propio-phenone, 375 
 Oxindol, 310 
 Oxy-aceto-phenone, 326 
 Oxy-acids, 376 
 Oxy-anthracenes, 705 
 Oxy-anthranile 301 
 Oxy-anthraquinones, 713 
 Oxy-anthrarufin, 717 
 Oxy-anthrone, 707 
 Oxy-azo-benzols, 204 
 Oxy-azo-compounds, 178 
 Oxy-benzal-acetone, 417 
 Oxy-benzalazin, 322 
 Oxy-benzo-hydrol. 566 
 Oxy-benzo-phenones, 572 
 Oxy-benzo-thiazol, 209 
 Oxy-benzoic Acids, 35, 334 
 Oxy-benzyl-amine, 315 
 Oxy-benzyl-benzols, 564 
 Oxy-benzyl-benzyu'dene-indene, 643 
 Oxy-benzlidene-aceto-phenone, 628 
 Oxy-biazoline Derivatives, 158 
 Oxy-biphenyls ; 556 
 Oxy-biphenyl-carboxylic Acids, 559 
 Oxy-camphor, 533 
 Oxy-carone, 574 
 Oxy-cinnamic Acid, 427 
 Oxy-cinnamylidene-acetic Acid. 437 
 Oxy-cumarin, 431, 437 
 Oxy-cyclopentane-carboxylic Acid, 21 
 Oxy-diazo-benzol-imide, 203 
 Oxy-dibenzal-acetone, 638 
 Oxy-dibromo-triphenyl-carbinol, 591 
 Oxy-dihydro-cyclo-geranic Acid, 474 
 Oxy-diphenyl-acetic Acid, 607 
 Oxy-diphenyl-amine, 201, 202 
 Oxy-diphenyl Sulphide, 180 
 Oxy-diphenylene-ketone, 699 
 Oxy-fenchene Acid, 525 
 Oxy-fluorenone, 699, 700 
 Oxy-glutaric Acid, 7 
 Oxy-hydrazo-benzol, 206 
 
750 
 
 INDEX 
 
 Oxy-hydro-carbo-styril, 381 
 Oxo-hydro-cumarin, 391 
 Oxy-hydroquinone, 223 
 Oxy-hydroquinone-benzein, 592 
 Oxy-hydroquinone-phthaleiin, 601 
 Oxy-iso-phthalic Acids, 361 
 Oxy-juglone, 673 
 Oxy-m-xylenols, 345 
 Oxy-mandelic Acid, 378 
 Oxy-mesitylene-aldehyde, 323 
 Oxy-mesitylenic Acids, 335 
 Oxy-methyl-benzoic Acids, 347 
 Oxy-raethyl-benzoic Acid Lactone, 347 
 Oxy-methylene-acetic Ester, 43 
 Oxy-methylene-aceto-phenone, 436 
 Oxy-methylene-acetone, 43 
 Oxy-methylene-camphor, 536 
 Oxy-methylene-menthone, 506 
 Oxy-methylene-phenyl-acetic Ester, 436 
 Oxy-methylene-phthalide, 437 
 Oxy-naphtho-quinones, 673 
 Oxy-naphthoic Acids, 678 
 Oxy-o-phthalic Acids, 359 
 Oxy-pentadecylic Acid, 722 
 Oxy-phenanthrenes, 690 
 Oxy-phenanthrene-quinone, 693 
 Oxy-phenyl-acetic Acids, 335 
 Oxy-phenyl-arsinic Acid, 170 
 Oxy-phenyl-ethyl-Alcohol, 316 
 Oxy-phenyl-ethyl-amine, 316 
 Oxy-phenyl-ethyl-carbinol, 316 
 Oxy-phenyl-fatty Acids, 335 
 Oxy-phenyl -lactic Acid, 381 
 Oxy-phenyl-olefin Alcohols, 414 
 
 Aldehydes, 415 
 
 Oxy-phenyl-olefin-carboxylic Acids, 426 
 Oxy-phenyl-olefin Ketones, 417 
 Oxy-phenyl-propionic Acids, 336 
 Oxy-phenyl-pyro-racemic Acid, 391 
 Oxy-phenyl-phthalide, 349, 574 
 Oxy-phenyl-urea, 201 
 Oxy-phenyl-urethane, 200 
 Oxy-phenyl-xanthydrol, 592 
 Oxy-phosphazp-benzol-anilide, 92 
 Oxy-pipitzahoic Acid, 231 
 Oxy-quinones, 230 
 Oxy-stilbene, 612 
 Oxy-styryl-benzyl-ketone, 633 
 Oxy-styryl-diphenyl-carbinol, 629 
 Oxy-suberane-acetic Acid, 25 
 Oxy-suberane-carboxylic Acid, 25 
 Oxy-sulphones, 180 
 Oxy-terephthalic Acids, 362 
 Oxy-terpenylic Acid, 509 
 Oxy-tetramethylene, n 
 Oxy-thymoquinone, 231 
 Oxy-toluic Acids, 334 
 Oxy-toluols, 187 
 Oxy-tricarbpxylic Acids, 365 
 Oxy-trimellitic Acid, 365 
 Oxy-trimesic Acid, 365 
 Oxy-triphenyl-carbinol, 590 
 Oxy-triphenyl-methane, 589 
 Oxy-triphenyl-methane-carboxylic Acids, 595 
 Oxy-uvitinic Acids, 361 
 Aldehyde, 347 
 
 PARA-ANTHRACENE, 703 
 Para-dinitro-benzpl, 70 
 Para-mandelic Acid, 376 
 Para-nitraniline, 32 
 Para-nitro-benzaldehyde, 261 
 Para-oxy-benzoic Acid, 31, 32, 36 
 Para-rosolic Acid, 593 
 Para-xylol, 36 
 Paracoto, 573 
 Paramide 366 
 Patchouli' Alcohol, 548 
 Penta-amido-benzol, 118 
 Penta-amido-pentol, 233 
 Penta-amido-toluene, 118 
 Penta-bromaniline, no 
 Penta-bromo-cyclo-butane, n 
 Penta-bromo-diketo-oxy-cyclo-hexenol, 461 
 Penta-bromo-toluol, 446 
 Penta-carbocyclic Compounds, 13 
 
 Penta-chloraniline, 110 
 Penta-chloro-glutaric Acid, 48 
 Penta-chloro-resorcin, 48 
 Penta-chloro-naphthalene, 659 
 Penta-ethyl-benzol, 55, 59 
 Penta-keto-cyclo-pentane, 232 
 Penta-keto-pentamethylene, 19 
 Penta-methyl-acetyl-cyclopentene, 19 
 Penta-methyl-benzoic Acid, 275 
 Penta-methyl-benzol, 55, 59 
 Penta-methyl-phenol, 189 
 Penta-methyl Violet, 588 
 Penta-methylene, i, 3, 13, 14 
 Penta-methylene-carbinol, 16 
 Penta-methylene-glycol, 16 
 Penta-methylene-methylamine, 16 
 Penta-nitro-diphenyl-amine, 112 
 Penta-phenyl-ethane, 625 
 Penta-phenyl-ethyl Alcohol, 626 
 Penta-phenyl-guanidin, 104 
 Pentamines, 113 
 Pentol, 15 
 
 Pentosides, 719, 723 
 Pentylene-di-o-toluidin, 90 
 Peonine, 593 
 
 Perchlor-acroyl-acrylic Acid, 47 
 Perchlor-ethylene, 42 
 Perchlorindone, 21, 647 
 Perchloro-acetyl-acrylic Acid, 48 
 
 Chloride, 48 
 
 Perchloro-cyclopentene, 14 
 Perchloro-diphenyl, 552 
 Perchloro-methane, 42 
 Perchloro-naphthalene, 659 
 Perchloro-vinyl-acrylic Acid, 47 
 Perhydro-diphenyl, 550 
 Perhydro-fluorene, 696 
 Peri-dioxy-naphthyl-ketones, 677 
 Peri-naphthol-carboxylic Acid, 679 
 Perkin, 485 
 
 Peroxide-phthalic Acid, 356 
 Persea Cassia, 415 
 Persio, 217 
 Perylene, 68 1 
 Petermann, 32 
 Petroselinum sativum, 412 
 Phaseolus vulgaris, 453 
 Phellandrene, 494, 495 
 Group, 494 
 
 Nitrite, 494 
 Phenacetin, 202 
 Phenacetol, 191 
 Phenacetyl-phenyl-alanin, 381 
 Phenacyl-acetone, 375 
 Phenacyl-anilide, 372 
 Phenacyl Bromide, 371 
 
 Chloride, 371 
 Phenacyl-cinnamic Acid, 635 
 Phenacyl-diacetyl-methane, 376 
 Phenacyl Iodide, 372 
 Phenacyl-laevulinic Acid, 396 
 Phenacyl-phthalide, 630 
 Phenacyl-succinic Acid, 539 
 Phenanthraquinone, 691 
 Phenanthraquinone-monoxime, 692 
 Phenanthrene, 50, 687, 689 
 Phenanthrene-carboxylic Acids, 690, 691 . 
 Phenanthrene-dicarboxylic Acid, 691 
 Phenanthrene Group, 687 
 Phenanthrene-hydroquinone, 690 
 Phenanthrene-quinone-sulphonic Acicl, 693 
 Phenanthrene-sulphonic Acids, 690 
 Phenanthridone, 560 
 Phenanthro-anthraquinone, 719 
 Phenanthrols, 690 
 Phenanthrol-carboxylic Acid, 691 
 Phenanthrone, 690 
 Phenanthrylamines, 690 
 
 Phenates, 186 
 Phenazin, 214 
 Phenazone, 553 
 Phene, 49 
 Phenetetrol, 223 
 Phenethyl-benzyl-ketone, 633 
 Phenethyl-succinic Acid, 397 
 Phenetol, 190 
 
INDEX 
 
 75i 
 
 Phenetol-carbamide, 202 
 Pheno-pentenal, 415 
 Pheno-phenyl-triazin, 292 
 Pheno-propyl-methylamine, 246 
 Pheno-quinone, 227 
 Pheao-triazin, 166 
 Phenols, 30, 31, 183, 185, 187, 188 
 Phenol Acids, 327 
 
 Alcohols, 187, 314 
 
 Phenol-alcohol Ethers, 189 
 Phenol-aldehydes, 321 
 Phenol-alkyl Ether, 169 
 Phenol-benzeln, 591 
 Phenol-diazo-chlorides, 203 
 Phenol Ethers, 191 
 Phenol-ethylene Ether, 190 
 Phenol Haloids, 193 
 
 Ketones, 325 
 
 Phenol-methylene Ether, 190 
 Phenol-monocarboxylic Acids, 327 
 Phenol-naphthalein, 680 
 Phenol-phenyl-ethane, 604 
 Phenol-phthalem, 598 
 Phenol-phthalem-anilide, 598 
 Phenol-phthalem Methyl Ester, 598 
 Phenol-phthalein-oxime, 598 
 Phenol-salicylic Ester, 330 
 Phenol Substitution Products, 193 
 Phenol-sulphonic Acids, 178, 206 
 Phenolates, 186 
 Phenose, 454 
 Phenoxalkylamines, 190 
 Phenoxazin, 200, 214 
 Phenoxethylamines, 190 
 Phenoxy-acetaldehyde, 191 
 Phenoxy-acetic Acid, 191 
 Phenoxy-aceto-acetic Ester, 191 
 Phenoxy -acetone, 191 
 Phenoxy-acetyl Chloride, 191 
 Phenoxy-acetylene, 190 
 Phenoxy-butylamine, 190 
 Phenoxy-butyric Acid, 191 
 Phenoxy-cinnamic Acid, 417 
 
 Ester, 436 
 
 Phenoxy-fumaric Ester, 191 
 Phenoxy-propylamine, 190 
 Phenoxyl-diphenyl-phosphine, 1 69 
 Phenoxyl-phosphazo-benzol, 93 
 Phenyl- a-methyl-sulpho-hydantoin, 102 
 Phenyl-acetaldehyde, 30, 31 
 Phenyl Acetate, 192 
 Phenyl-acetic Acid, 31, 276 
 
 Azide, 284 
 
 Ethyl Ester, 278 
 
 Hydrazide, 284 
 Phenyl-aceto-acetic Ester, 393 
 Phenyl-aceto-phenone, 559 
 Phenyl-aceto-succinic Ester, 399 
 Phenyl-acetyl-carbinol, 373 
 Phenyl-acetyl Chloride, 279 
 Phenyl-acetyl-malonic Ester, 399 
 Phenyl-acetyl-thio-urea, 102 
 Phenyl-acetylene, 407 
 
 Alcohols, 414 
 
 Aldehydes, 417 
 
 Phenyl-acetylene-carboxylic Acids, 431 
 Phenyl-acetylene-copper, 407 
 Phenyl-acetylene Di-iodide, 405 
 
 Ketones, 417 
 
 Phenyl-acetylene-phenyl-carbinol, 630 
 Phenyl-acetylene-silvef, 407 
 Phenyl-acetylene-sodium, 407 
 Phenyl-acrylic Acids, 419, 425 
 Phenyl-alanin, 98, 380 
 Phenyl-alcohol Aldehydes, 370 
 Phenyl-alcohol-dicarboxylic Acids, 397 
 Phenyl-alcohol-ketone-carboxylic Acids, 394 
 Phenyl-aldehdye Ketones, 373 
 Phenyl-alkyl-ammonium Bases, 88 
 Phenyl-alkyl Chlorides, 243 
 Phenyl-alkyl-hydrazins, 151 
 Phenyl-alkylamine, 87 
 Phenyl-allophanic Ester, 100, 193 
 Phenyl-allyl-acetic Acid, 426 
 Phenyl-allyl-sulphone, 182 
 Phenyl-allylene, 407 
 
 Phenyl-amido-acetic Acid, 379 
 Phenyl-amido-carbonyl-chloride, 97 
 Phenyl-amido-azo-benzol-[3]-sulphonic Acid, 179 
 Phenyl-amido-azo-benzol-[4]-sulphonic Acid, 179 
 Phenyl-angelica Acid, 424 
 Phenyl-anthracene, 704 
 Phenyl-anthranile, 303, 570 
 Phenyl-anthranilic Acid, 306 
 
 Formalide, 307 
 
 Phenyl-anthranilido-acetic Acid, 308 
 Phenyl-arsenious Chloride, 170 
 Phenyl-arsinic Acid, 170 
 Phenyl-aticonic Acid, 440 
 Phenyl-azo-acetaldoxime, 165 
 Phenyl-azo-aldoximes, 163, 165 
 Phenyl-azo-amido-benzol, 140 
 Phenyl-azo-benzaldoxime, 291 
 Phenyl-azo-formaldoxime, 165 
 Phenyl-azo-formazyl, 166 
 Phenyl-azo-nitro-acid, 164 
 Phenyl-azo-nitroso-benzol, 140 
 Pheoyl-benzaldehyde, 559 
 Phenyl-benzaldoxime, 260 
 Phenyl -benzalsultime, 569 
 Phenyl -benzamide, 281 
 Phenyl-benzamidin, 290 
 Phenyl-benzene Sulphazide, 148 
 Phenyl-benzo-hydrylamine, 565 
 Phenyl-benzo-quinpne, 557 
 Phenyl-benzoic Acid, 559 
 Phenyl-benzols, 549, 550 
 Phenyl-benzol-sulphazide, 157 
 Phenyl-benzyl-ketone, 613 
 Phenyl-biguanide, 104 
 Phenyl-biuret, 100 
 Phenyl-boron Bromide, 170 
 
 Chloride, 170 
 
 Compounds, 170 
 
 Phenyl-bromacetic Acid, 378 
 Phenyl-bromo-acetylene, 407 
 Phenyl-bromo-tetrahydro-naphthoic Acid, 636 
 Phenyl-butadiSne, 408 
 Phenyl-butane-tricarboxylic Acid, 400 
 Phenyl-butylene-glycol, 368 
 Phenyl-butyric Acid, 277 
 Phenyl -butyraldehyde, 256 
 Phenyl-butyro-lactone, 608 
 Phenyl-carbamic Azide, 101 
 
 Phenyl Ester, 193 
 
 Phenyl-carbaminate, 193 
 Phenyl-carbaminic a- Phenyl -hydrazide, 160 
 
 Acid, 99 
 
 Hydrazide, 100 
 
 Phenyl Ester, 193 
 
 Thio-methyl Ester, 101 
 
 Phenyl-carbazinic Ethyl Ester, 160 
 Phenyl-carbinol, 241 
 Phenyl Carbonates, 192 
 Phenyl-carboxy-aconitic Ester, 441 
 Phenyl-carbylamine, 89, 97 
 Phenyl-chloracetic Acid, 378 
 Phenyl-chloro-acetylene, 407 
 Phenyl-chloro-fluorene, 697 
 Phenyl-chloroform, 31, 297 
 Phenyl-chryso-fluorene, 698 
 Phenyl-cinnamenyl-acrylic Acid, 635 
 Phenyl-cinnamic Acid, 608 
 
 Nitrite, 621 
 
 Phenyl-citraconic Acid, 440 
 Phenyl-cumalin, 437 
 Phenyl-cumaran, 629 
 Phenyl-cumarin, 622 
 Phenyl-cyanamide, 106 
 Phenyl-cyano-acetic Acid, 396 
 Phenyl-cyano-pyro-racemic Ester, 399 
 Phenyl-cyano-triazene, 136 
 Phenyl -cyclo-hexane, 550 
 Phenyl-cyclopentenone, 17 
 Phenyl-diazo-methane, 248 
 Phenyl-dihaloid-acryh'c Acids, 422 
 Phenyl-dihydro-resorcin, 459 
 Phenyl-diketo-hexahydro-a-triazin, 158 
 Phenyl-dimethyl Carbinol, 242 
 Phenyl-dimethyl-pyrimidin, 290 
 Phenyl-dimethylamine, 79 
 Phenyl-dinitro-methane, 257 
 
752 
 
 INDEX 
 
 Phenyl-diolefin Aldehydes, 416 
 Phenyl-diolefin-carboxylic Acids, 433 
 Phenyl-diolefin Ketones, 417 
 Phenyl-dioxy-olefine-carboxylic Acids, 437 
 Phenyl-disulphide. 209 
 Phenyl-dithio-carbaminic Methyl Ester, 101 
 Phenyl-dithio-carbazimic Acid, 161 
 
 Phenyl-hydrazin, 161 
 
 Phenyl-dithio-carbonic Ester, 208 
 Phenyl-dithio-urethane, 101 
 Phenyl-dithymol-methane, 590 
 Phenyl Esters, 181 
 Phenyl-ethenyl-amidin, 97 
 Phenyl Ether, 191 
 Phenyl-ethyl-alcohol, 30, 31 
 Phenyl-ethyl-amine, 246 
 Phenyl-ethyl Carbonate, 192 
 Phenyl-ethyl-nitrosamine, 119 
 Phenyl-ethyl Sulphide, 210 
 Phenyl-ethyl-sulphone, 182 
 
 Alcohol, 182 
 
 Phenyl-ethylene, 404 
 
 Oxide, 368 
 
 Phenyl-fatty Acids, 275 
 
 Nitriles of, 286 
 
 Phenyl-fluorene, 697 
 Phenyl-fluorone, 592 
 Phenyl Formate 192 
 Phenyl-formic Acid, 31, 273 
 Phenyl-formyl-acetic Ethyl Ester. 387 
 Phenyl-fumaric Ester, 193 
 Phenyl-glutaconic Acid, 441 
 Phenyl-glutaric Acid, 397 
 Phenyl-glyceric Acid, 256 
 Phenyl-glycerin, 367 
 
 Aldehyde, 370 
 
 Phenyl-glycidic Acid, 386 
 
 Ether, 190 
 
 Phenyl-glycin, 97 
 Phenyl-glycocoll, 97 
 Phenyl-glycollic Acid, 376 
 Phenyl-glycols, 367 
 Phenyl-glyoxal, 267, 373 
 Phenyl-glyoxylic Acid, 387 
 Phenyl-guanidin, 104 
 Phenyl-hexadiene, 408 
 Phenyl-hexamethylene-carboxylic Acid, 559 
 Phenyl-hydantom, 100 
 Phenyl-hydracrylic Acid, 382 
 Phenyl-hydrazi-methylene-carboxylic Acid, 388 
 Phenyl-hydrazide, 158, 287 
 Phenyl-hydrazidine, 164 
 Phenyl-hydrazido-acetic Acid, 158 
 Phenyl-hydrazido-acids, Hetero-ring Formation of, 
 
 158 
 
 Phenyl-hydrazido-/3-butyric Acid, 158 
 Phenyl-hydrazido-j3-propionic Ester, 158 
 Phenyl-hydrazido-formic ester, 160 
 Phenyl-hydrazin, 145, 149 
 
 Carboxylic Acid Derivatives of, 157 
 
 Chlorohydrate, 149 
 
 Derivatives of Carbonic Acid, 159, 161 
 
 of Inorganic Acids, 156 
 
 Group, 148 
 
 Phenyl-hydrazin-p-sulphonic Acid, 179 
 Phenyl-hydrazin-phenyl-carbazinate, 159 
 Phenyl-hydrazin-sulphinic Acid, 156 
 Phenyl-hydrazin-sulphonic Acids. 156, 179 
 Phenyl-hydrazin-urea, 160 
 Phenyl-hydrazo-acetaldoxime, 165 
 Phenyl-hydrazo-aldoximes, 163, 165 
 Phenyl-hydrazo-formaldoxime, 165 
 Phenyl-hydrazones, 152, 254, 322, 674 
 
 Transformations of, 155 
 
 Phenyl-hydro-naphthalene, 684 
 Phenyl-hydro-nitric Ester, 138 
 Phenyl-hydroxyl-thio-urea, 103 
 Phenyl -hydroxyl-urea, 100 
 Phenyl-hydroxylamine, 69, 78 
 Phenyl-imido-carbonic Phenyl Ester, 193 
 Phenyl-imido-carbonyl Chloride, 105 
 Phenyl-imido-formyl-chloride, 97 
 Phenyl-imido-oxalic Dimethyl Ester, 108 
 
 Phenyl - imido - phenyl - carbaminic thio - methyl 
 
 Ester, 103 
 Phenyl-imido-thio-carboxylic Acid, 101 
 
 Phenyl-imino-benzo-phenone, 569 
 Phenyl -indoxazene, 571 
 Phenyl-iodo-acetylene, 407 
 Phenyl-iodo-chloride, 61 
 Phenyl-iso-amyl Carbinol, 242 
 Phenyl-iso-butyl, 242 
 Phenyl-iso-crotone-phenone, 633 
 Phenyl-iso-crotonic Acid, 424 
 Phenyl Iso-cyanate, 104 
 Phenyl-iso-cyanide, 97 
 Phenyl-iso-phthalic Acid, 560 
 Phenyl-iso-propyl, 242 
 Phenyl-iso-oxazolonimide, 393 
 Phenyl-itaconic Acid, 440 
 Phenyl-itamalic Acid, 398 
 
 Phenyl-keto-pentamethylene-dicarboxylic Acid, 21 
 Phenyl-keto-tricarboxylic Acids, 400 
 Phenyl Ketols, 371 
 
 Phenyl-ketone-dicarboxylic Acids, 399 
 Phenyl-lactazame, 575 
 Phenyl-lactic Acids, 379, 382 
 Phenyl-magnesium Bromide, 171 
 
 Iodide, 171 
 
 Phenyl-maleic Acid, 440 
 Phenyl-malic Acids, 398 
 Phenyl-malonic Acids, 396 
 Phenyl-mesaconic Acid, 440 
 Phenyl Metal Derivatives, 171 
 Phenyl-methane, 31 
 Phenyl-methyl-acetylene, 407 
 Phenyl-methyl-alcohol, 31 
 Phenyl-methyl-butadiene, 408 
 Phenyl-methyl Carbinol, 242 
 
 cyanamide, 106 
 
 Phenyl-methyl-ethyl-propyl-silicon, 1 70 
 Phenyl-methyl-ethylene Oxide, 368 
 Phenyl-methyl-formhydrazin, 164 
 Phenyl-methyl-glycol, 367 
 Phenyl-methyl-glyoxime, 375 
 Phenyl-methyl Ketone, 266 
 Phenyl-methyl-nitramine, 120 
 Phenyl-methyl-nitrosamine, 119 
 Phenyl-methyl-oxy-pyrimidin, 290 
 Phenyl-methyl-pentadiene, 408 
 Phenyl-methyl-pseudo-thio-urea, 102 
 Phenyl-methyl-sulphide, 210 
 Phenyl-methyl-triazol, 165 
 Phenyl-methyl-triketone, 375 
 Phenyl-methylamine, 79 
 Phenyl -methylamine Chlorohydrate, 82 
 Phenyl-methylol, 241 
 Phenyl-monohaloid-acrylic Acids, 421 
 Phenyl-mustard Oil, 106 
 Phenyl-naphtho-xanthene, 682 
 Phenyl-naphthyl-ketones, 677 
 Phenyl-naphthylamines, 660 
 Phenyl -nitramines, 120 
 Phenyl-nitro-acetic Ester, 378 
 Phenyl-nitro-aceto-nitrile, 378 
 Phenyl-nitro-ethylene, 405 
 Phenyl-nitro-f ormaldehydrazone, 291 
 Phenyl-nitro-isoxazol, 415 
 Phenyl-nitro-methane, 244 
 Phenyl-nitro-paraffins, 244 
 Phenyl-nitrosamines, 118 
 Phenyl-nitroso-hydrazin, 166 
 Phenyl -olefin Alcohols, 413 
 
 Aldehydes, 415 
 
 Phenyl-olefin-carboxyh'c Acids, 418 
 Phenyl-olefin-ketols, 436 
 Phenyl-olefin Ketones, 416 
 Phenyl-olefin-tricarboxylic Acids, 441 
 Phenyl-opiazone, 352 
 Phenyl-ortho-formic Ester, 192 
 Phenyl-oxalacetic Ester, 399 
 Phenyl-oxalic Ester, 193 
 Phenyl-oxalkyl-amines, 369 
 Phenyl-oxamide, 107 
 Phenyl-oxaminic Diphenyl-amidine, 108 
 Phenyl-oxanthranyl Chloride, 707 
 Phenyl-oxethyl-amine, 369 
 Phenyl-oxy-ketone-dicarboxylic Acids, 400 
 Phenyl-oxy-olenn-dicarboxyh'c Acids, 441 
 Phenyl-oxy-propionic Acids, 379 
 Phenyl-p-toluidin, 92 
 Phenyl-parabanic Acid, 109 
 
INDEX 
 
 753 
 
 Phenyl-paraconic Acid, 398 
 
 Phenyl-paraffin Alcohols, 239 
 
 Alcohol Acids, 376 
 
 Phenyl-paraffin-aldehyde-carboxylic Acids, 386 
 
 Phenyl-paraffin Amines, 245 
 
 Phenyl-paraffin-dicarboxylic Acids, 396 
 
 Phenyl-paraffin Diketones, 374 
 
 Phenyl-paraffin-ketone-carboxylic Acids, 387 
 
 Phenyl-paraffin-tricarboxylic Acids, 400 
 
 Phenyl-pentadiene, 408 
 
 Phenyl-phosphine, 169 
 
 Phenyl-phosphorus Compounds, 168 
 
 Phenyl-phthalazone, 351 
 
 Phenol-phthalol, 594 
 
 Phenyl-piperidin, 60 
 
 Phenyl-propargyl Aldehyde, 417 
 
 Phenyl-propenyl-ketone, 417 
 
 Phenyl-propiolic Acid, 431, 652 
 Ethyl Ester, 432 
 
 Phenyl-propionic Acid, 31 
 
 Phenyl-propyl Alcohols, 242 
 
 Phenyl-propyl -aldehyde, 256 
 
 Phenyl-pyro-racemic Acid, 391 
 
 Phenyl-salicylic Acid, 330, 559 
 
 Phenyl-semicarbazide, 100, 160 
 
 Phenyl Silicates, 192 
 
 Phenyl-silico-chloride, 170 
 
 Phenyl-sih'cpn Compounds, 170 
 
 Phenyl-stibinic Acid, 170 
 
 Phenyl -stibinous Chloride, 170 
 
 Phenyl-succinic Acid, 396 
 
 Phenyl-sulphaminic Acid, 93 
 
 Phenyl Sulphide, 209 
 
 Phenyl-sulpho-aceto-nitrile, 182 
 
 Phenyl-sulpho-cyanide, 105 
 
 Phenyl-sulpho-hydantolns, 102 
 
 Phenyl-sulpho-semicarbazide, 161 
 
 Phenyl-sulpho-urea, 101 
 
 Phenyl-sulphone Acetamide. 182 
 
 Phenyl-sulphone-acetic Acid, 182 
 
 Phenyl-sulphonic Ester, 191 
 
 Phenyl-sulphoxy-acetic Acid, 181 
 
 Phenyl-sulphur-ethane, 101 
 
 Phenyl-sulphuric Acid, 191 
 
 Phenyl-tartronic Methyl Ester, 398 
 
 Phenyl-tetronic Acid, 395 
 
 Phenyl-tetrose, 371 
 Phenyl-thio-acetyl Bisulphide, 280 
 Phenyl-thio-biazolone-sulphohydrate, 161 
 
 Phenyl-thio-carbaminic a-Phenyl-hydrazide, 161 
 
 /3-Phenyl-hydrazide, 161 
 
 Hydrazide, 103 
 
 Phenyl-thio-carbonic Chloride, 208 
 Phenyl-thio-glycolic Acid, 210 
 Phenyl-thio-salicylic Acid, 333 
 Phenyl-thio-semicarbazide, 103 
 Phenyl-thio-sulphonic Aceto-acetic Ester, 181 
 Phenyl-thiuram-sulphide, 101 
 Phenyi-tin Compounds, 171 
 Phenyl-tolyl-disulphone, 181 
 Phenyl-tolyl-ketone, 568 
 Phenyl-tolyl-propane, 610 
 Phenyl-triazene, 134 
 Phenyl-triazole, 158 
 Phenyl-tricarballylic Acid, 400 
 Phenyl-trimethyl-ammonium Iodide, 82 
 Phenyl-trimethyl-hydrazin, 152 
 Phenyl-trimethylene-carboxylic Acid, 8 
 Phenyl-trioxy-fluorone, 592 
 Phenyl-urazol, 161 
 Phenyl-urea, 99 
 
 Chloride, 99 
 
 Phenyl-urethanes, 99, 193 
 Phenyl-valerianic Acid, 277 
 Phenyl-vinyl-amine, 406 
 Phenyl-vinyl-ethyl Ether, 413 
 Phenyl-vinyl-ketbne, 417 
 Phenyl-vinyl-methyl Ether, 413 
 Phenyl-vinyl-phenyl Ether, 413 
 Phenyl-xanthydrols, 591 
 Phenyl-xylyl-propane, 610 
 Phenylamine, 79 
 Phenylamines, Primary, 80 
 
 Properties and Transformations of, 82 
 
 Phenylated Fatty Ketones, 267, 268 
 Para-rosanilins, 589 
 
 VOL. II. 
 
 Phenylated Rosanilins, 589 
 
 Phenylene, 602 
 
 Phenylene-aldehydo-carbpxylic Acids, 435 
 
 Phenylene-alkylene-diamines, 116 
 
 Phenylene-bis-diazo-chloride, 126 
 
 Phenylene-bis-diazo-imide, 138 
 
 Phenylene Blue, 239 
 
 Brown, 145 
 
 Phenylene-carbyl-amine, 114 
 
 Phenylene-diacrylic Acid, 436 
 
 Phenylene-diamido-monosulphonic Acid, 178 
 
 Phenylene-diamines, 114, 115 
 
 Phenylene-dicarboxylic Acids, 435 
 
 Phenylene-dicarbyl-amine, 115 
 
 Phenylene-disazo-m-phenylene-diamine, 145 
 
 Phenylene-ketone-dicarboxylic Acids, 402 
 
 Phenylene-naphthylene, 695 
 
 Phenylene-naphthylene Oxide, 726 
 
 Phenylene-oxy-dicarboxylic Acids, 401 
 
 Phenylene-oxy-olefin-carboxylic Acids, 434 
 
 Phenylene-oxy-olefin-dicarboxylic Acids, 442 
 
 Phenylene-sulphonylide, 207 
 
 Phenylisuretin, 97 
 
 Phloretic Acid, 336 
 
 Phloretin, 221, 336 
 
 Phlorizin, 721 
 
 Phloro-baphene, 343 
 
 Phloro-glucin, 48, 221 
 
 Phloro-glucin-aldehyde, 325 
 
 Phloro-glucin-carboxylic Acid, 341 
 
 Phloro-glucin-dicarboxylic Ester, 483 
 
 Phloro-glucin-phthalein, 601 
 
 Phloro-glucin Trioxime, 222 
 
 Phloro-glucite, 222, 453 
 
 Phloxin, 601 
 
 Phosph-azo-benzol Chloride, 93 
 
 Phosph-azo-benzol-anilide, 93 
 
 Phosphaniline, 169 
 
 Phosphenyl Chloride; 169 
 
 Sulpho-chloride, 169 
 
 Phosphine-benzoic Acids, 312 
 
 Phospbino-benzene, 169 
 
 Phospho-benzol, 169 
 
 Phosphoro-phenylamines, 93 
 
 Photo-santonic Acid, 725 
 
 Phthal-acene, 701 
 
 Phthal-aldehyde Chlorides, 352 
 
 Phthal-aldehydic Acid, 351 
 
 Methyl Ether, 351 
 
 Phthal-amic Acid, 356 
 
 Phthal-ane. 344 
 
 Phthal-azin, 346 
 
 Phthal-azone, 351 
 
 Phthaleins, 597 
 
 Phthalic Acids, 35, 36, 37, 354 
 
 Acid Aldehydes, 346 
 
 Anhydride; 356 
 
 Diamide, 356 
 
 Phthalide, 347 
 
 Phthalide-acetic Acid, 401 
 
 Phthalide Anile. 348 
 
 Phthalide-carboxylic Acid. 401 
 
 Phthalide Chloride, 348 
 
 Phthalide-propionic Acid, 402 
 
 Phthalide-tricarboxylic Acid, 403 
 
 Phthalideins, 597, 707 
 Phthalidins, 597, 707 
 
 Phthalimide, 356 
 Phthalimidin, 348 
 PhthaUmino-aceto-phenone, 372 
 Phthalins, 597 
 
 Phthalo-mono-super Acid, 356 
 Phthalo-nitrile, 358 
 Phthalo-phenones, 576 
 Phthalonic Acid, 402 
 Phthalyl-acetic Acid, 442 
 Phthalyl-alanin, 358 
 Phthalyl Chloride, 355 
 Phthalyl-diacetic Acid, 403 
 Phthalyl-dimalonic Acid, 403 
 Phthalyl-glutaric Esters, 642 
 Phthalyl-glycocoll, 357 
 Phthalyl-hydrazin, 357 
 Phthalyl-hydroxylamine, 357 
 Phthalyl-hydroxylaminic Acid, 357 
 Phthalyl-malonic Ester, 442 
 
 3C 
 
754 
 
 INDEX 
 
 Phthalyl Peroxide, 356 
 Phthalyl-phenyl-hydrazide, 357 
 Phthalyl-phenyl-hydrazin, 357 
 Phthalylene Tetrachlorides, 356 
 Piazo-selenols, 116 
 Piazo-thiols, 116 
 Picamar, 221 
 Piceane Ring, 13 
 Picene, 693, 694 
 Picene-fluorene, 695, 697 
 Picene-ketone, 699 
 Picene-perhydride, 695 
 Picramic Acid, 202 
 Picric Acid, 184, 196 
 Picro-cyaminic Acid, 197 
 Picro-erythrin, 339 
 Picro-toxin, 724 
 Picro-toxinin, 724 
 Picrotin, 724 
 
 Picryl-anthranilic Acid, 306 
 Picryl Bromide, 72 
 
 Chloride, 184 
 
 Picryl-malonic Ester, 396 
 Picylene-methane, 697 
 Pimaric Acid, 548 
 Pimpinella anisum, 410 
 Pinane, 513 
 
 Group, 515 
 
 Pinene, 13, 515, 519 
 
 Dibromide, 519 
 
 Pinene-glycol, 516, 519 
 Pinene Hydrate, 520 
 
 Hydro-bromide, 518 
 
 Hydro-chloride, 518 
 
 Hydro-iodide, 518 
 
 Nitroso-bromide, 519 
 
 Nitroso-chloride, 519 
 
 Pinic Acid, 13 
 Finite, 454 
 Pino-campheol, 520 
 Pino-camphone, 519, 521 
 Pino-camphylamine, 521 
 Pino-carveol, 520 
 Pino-carvone, 521 
 Pinol-chloro-hydrins, 521 
 Pinol dibromide, 521 
 Pinol-glycol, 521 
 Pinol Hydrate. 520 
 
 Nitroso-chloride, 521 
 
 Oxide, 521 
 
 Pinolone, 521 
 Pinonic Acid, 516 
 Pinoyl-formic Acid, 516 
 Pinus Lambertiana, 454 
 Pinus maritima, 548 
 Pinylamine, 519, 521 
 Piperic Acid, 433 
 Piperonal, 324 
 
 Chloride, 324 
 
 Piperonoyl-carboxylic Acid, 390 
 Piperonyl Acid Dibromide, 386 
 Piperonyl-acrolem, 416 
 Piperonyl-acrylic Acid, 430 
 Piperonyl Alcohol, 321 
 Piperonylene-acetone, 418 
 Piperonylene-malonic Acid, 440 
 Piperonylic Acid, 338 
 Pipitzaho'ic Acid, 231 
 Pittical, 594 
 
 Poly-benzoyl Cyanide, 388 
 Poly-carboxylic Acids, 354 
 Poly-gonin, 723 
 Poly-gonine, 717 
 Poly-haloid Phenols, 194 
 Poly-hydric Aromatic Alcohols, 344 
 Poly-phenyl-fatty Hydrocarbons, 549 
 Poly-phenylamines, 91 
 Poly-quinoyls, 230 
 Poly-quinoyl Compounds, 231 
 Poly-sulphonic Acids, 176 
 Poly-terpenes, 546 
 Poly-thymo-quinone, 229 
 Poly-valent Ring-alcohols, 452 
 Polymerisation, 44 
 Populin, 720 
 Potassium Anilide, 85 
 
 Potassium Chloranilate, 230 
 
 Diazo-benzol, 119 
 
 Diazo-benzolic Acid, 119 
 
 Potassium-benzyl Diazotate, 248 
 Potassium Euthio-chronate, 230 
 
 Iso-diazo-benzol, 119, 127 
 
 Iso-p-diazo-toluol, 127 
 
 Myronate, 720 
 
 Phenate, 186 
 
 Phenyl-hydrazin, 150 
 
 Phthalimide, 357 
 
 Potassium-salicylic Aldehyde, 322 
 
 Prehnidin, 87 
 
 Prehnitic Acid, 366, 403 
 
 Prehnitol 55, 58 
 
 Primary Potassium-iso-diazo-sulphonate, 178 
 
 Prismatic Scheme, 41 
 
 Prom, 273 
 
 Propene-pyrocatechin, 213 
 
 Propenyl-anisol, 410 
 
 Propenyl-benzol, 406 
 
 Propenyl-naphthalin, 658 
 
 Propenyl-phenol, 409 
 
 Propiolic Acid, 43 
 
 Propionyl-iso-butyryl-phenyl-hydrrizide, 157 
 
 Propionyl-phenpl, 326 
 
 Propyl-acetanilide, 95 
 
 Propyl-benzoic Acids, 275 
 
 Propyl-benzol. 30, 57 
 
 Propyl-cyclo-hexane, 446 
 
 Propyl-mesitylene, 59 
 
 Propyl-phenol, 188 
 
 Protea mellifera, 338 
 
 Proteaic Acid, 338 
 
 Proto-catechuic Acid, 337 
 
 Aldehyde, 323 
 
 Proto-coto'in, 573 
 
 Prulaurasin, 723 
 
 Pseudo-cumenol, 188 
 
 Pseudo-cumidin, 86 
 
 Pseudo-cumol, 55, 57 
 
 Pseudo-cumol-5-sulphonic Acid, 175 
 
 Pseudo-cumyl-hydrazin, 150 
 
 Pseudo-diphenyl-thiohydanto'in, 103 
 
 Pseudo-diphenyl-thiohydantoi'nic Acid. 103 
 
 Pseudo-ephedrin, 369 
 
 Pseudo-ionone, 490 
 
 Pseudo-opianic Acid, 353 
 
 Pseudo-phenols, 317 
 
 Pseudo-phenol Alcohol Haloids, 317 
 
 Pseudo-phenyl-thiohydantoin ,103 
 
 Pseudo-phenyl-thiohydantoinic Acid, 103 
 
 Pseudo-phthal-imidin, 348 
 
 Pseudo-purpurin, 717 
 
 Pseudo-saccharin Chloride, 314 
 
 Pterocarpus, 212 
 
 Pterocarpus erinaceus, 343 
 
 Ptyalin, 720 
 
 Piychotis ajowan, 188 
 
 Pulegenic Acid, 508 
 
 Pulegon, 507 
 
 Pulegonamine, 504 
 
 Pulegone, 508 
 
 Pulvic Acid, 637 
 
 Purpur, 217 
 
 Purpurin, 702, 716 
 
 Purpurin-amide, 717 
 
 Purpurin-carboxylic Acid, 717 
 
 Purpuro-xanthin, 715 
 
 Pyranthrone, 718 
 
 Pyrazoles, 155 
 
 Pyrazolidones, 159 
 
 Pyrazolins, 155 
 
 Pyrene, 50, 695 
 
 Pyrene-ketone, 695 
 
 Pyrene-quinone, 695 
 
 Pyrenic Acid, 695 
 
 Pyro-catechin, 35, 212 
 
 Pyro-catechin-carbonic Hydrazide, 213 
 
 Pyro-catechin Chloro-phosphine, 213 
 
 Pyro-catechin-diphenyl Ether, 213 
 
 Pyro-catechin-methyl Ether, 212 
 
 Pyro-catechin-methylene, 213 
 
 Pyro-catechin Oxy-chloro-phosphine, 213 
 
 Pyro-catechin-phenyl-phthalide, 596 
 
 Pyro-catechin Sulphite, 213 
 
INDEX 
 
 755 
 
 Pyro-catechol, 212 
 
 Hetero-ring Formations from, 
 
 Pyro-catechol-sulphuric Acid, 212 
 Pyro-condensation. 43, 51 
 Pyro-gallol, 220, 340 
 Pyro-gallol-aldehyde, 325 
 Pyro-gallol Carbonate, 221 
 Pyro-gallol-carboxylic Acid, 341 
 Pyro-gallol-pheuyl-phthalide, 596 
 Pyro-gallol-phthaleln, 601 
 Pyro-gallol-succineln, 599 
 Pyro-genic Synthesis, 51 
 Pyro-mellitic Acid, 365 
 Pyro-racemic Acid, 164 
 Anilide, 98 
 
 Chloride, 97, 98 
 
 Pyro-terebinic Acid, 518 
 Pyro-traubem'c Acid, 43 
 Pyrones, 255 
 Pyrrol, 633 
 
 QUERCETRIN, 221 
 Quercite 453 
 Quercitrin, 723 
 Quercus infectoria, 342 
 
 tinctoria, 723 
 
 Quin-alizarin, 717 
 Quina-aceto-phenone, 327 
 Quinhydrone, 227 
 Quinic Acid, 226, 474 
 Quinisatin, 395 
 Juinisatinic Acid, 395 
 
 inite, 226, 453 
 
 linizarin, 715 
 }uinolene-phenylene-ketone, 649 
 
 liiiols, 465 
 
 inones, 115, 224. 671 
 
 inone Anilin-imine. 237 
 
 Azine, 23 
 
 Chlorimines, 235 
 
 Di-anile, 238 
 
 Diazides, 236 
 
 Dichlorimine, 115, 235 
 
 Di-imine, 115, 234 
 
 Dimethyl-anilin-imine, 237 
 
 Dimethyl-imine, 115 
 
 Dioximes, 226, 233 
 Quinone-dioxime-carboxylic Ester, 482 
 Quinone Haloids, 229 
 
 Imines, 233 
 
 Quinone-methanes, 317 
 Quinone Mono-anil, 236 
 
 mono-chlorimine, 235 
 
 mono-imine, 234 
 
 mono-methyl-imine, 234 
 
 Quinone-monoxime, 199 
 Quinone Oxime, 226 
 Quinone-oxime-hydrazone, 235 
 Quinone, Phenol Addition Products of, 227 
 
 Phenol-imine, 236 
 
 Phenyl-di-imines, 237 
 
 Quinone-phenyl-hydrazones, 235 
 Quinone-phenyl Mono-imine, 236 
 Quinone Semi-carbazone. 235 
 
 Tetrabromide, 460 
 Quinone-tetracarboxylic Ester, 365 
 Quinoxalins, 116 
 
 Quinoyl, 226, 231 
 
 Ranunculacece, 724 
 Resaceto-phenone, 326 
 Resaurin, 594 
 Residual Valences, 42 
 Resins, 548 
 
 Resorcin, 35, 48, 215, 217 
 Resorcin-benzeln, 592 
 Resorcin-dialdehyde, 346 
 Resorcin-phthalem, 599 
 Resorcyl-aldehyde, 325 
 Resorcyl-maleinic Lactone, 440 
 Resorcyl-phenyl-phthalide, 596 
 Resorcylic Acid, 338 
 Retene, 693 
 Retene-diphenic Acid, 693 
 
 Retene Dodeca-hydride, 693 
 Retene-fluorene, 697 
 Retene-glycollic Acid, 693 
 Retene-ketone, 693, 699 
 Retene-quinone, 693 
 Rhamnose, 723 
 Rhamnosides, 723 
 Rhamnus frangula, 717, 724 
 Rhelnic Acid, 716 
 Rhodamins, 601 
 Rhodan-acetanilide, 103 
 Rhodinal, 489 
 Rhodinic Acid, 490 
 Rhodizonic Acid, 231 
 Rhus coriaria, 342 
 Ring-ketols, 458 
 Ring Olefins, i 
 Robiquet, 723 
 Roccella, 217 
 
 fuciformis, 339 
 
 Rocellin, 668 
 Romer, 149 
 Rosamines, 592 
 Rosamine Chloride, 593 
 Rosanilin, 585 
 
 Rosanilin-sulphonic Acid, 587 
 Rosaniline, 91 
 Roshydrazin, 589 
 Rosoh'c Acids, 590, 593, 594 
 Rubeanic Hydride, 164 
 Ruberythric Acid, 714, 722 
 Rubia ttnctorium, 714, 722 
 Rungallic Acid, 341, 717 
 Rufiopin, 717 
 Rufol, 705, 706 
 Runge, 186 
 
 SABATIER, 443 
 Sabinane, 511 
 Sabinene, 510 
 
 Hydrate, 511 
 
 Sabinol, 512 
 Sabinyl-glycerin, 512 
 Saccharin, 173, 314 
 Safranins, 117 
 Safrol, 368, 411 
 Safrosine, 600 
 Salicin, 720 
 
 Salicyl-acetic Acid, 330 
 Salicyl-amide, 332 
 Salicyl-amine, 315 
 Sah'cyl-anilide, 332 
 Salicyl Chloride, 330 
 Salicyl-hydramide, 322 
 Salicyl-hydrazone, 322 
 Salicyl-lactic Acid, 381 
 Salicyl-uric Acid, 332 
 Salicylates, 329 
 Salicylic Acid, 36, 328 
 SaUcyu'c-acid Azide, 332 
 
 Hydrazide, 332 
 
 Phthalide, 602 
 
 Salicylic Aldehyde, 322 
 
 Salicylides, 331 
 
 Salicylide Chloroform, 331 
 
 Salicylo-nitrile, 332 
 
 SaUcylo-phosphoric Chloride, 331 
 
 Salicylo-salicylic Acid, 331 
 
 SaUcylous Acid, 322 
 
 Saligenin, 315 
 
 SaUnetin, 315 
 
 Sambunigrin, 723 
 
 Santalene, 547 
 
 Santalol, 547 
 
 Santalum album, 547 
 
 Santene, 526 
 
 Santoic Acid, 724 
 
 Santonic Acid, 724 
 
 Santonin, 724 
 
 Saponaria officinalis, 722 
 
 Saponarin, 722 
 
 Saponin, 722 
 
 Sassafras officinalis, 411 
 
 Saytzew, 334 
 
 Scammomn, 722 
 
756 
 
 INDEX 
 
 Schorleminer, 586 
 
 Scyllite, 454 
 
 Secondary phenyl-alkylamines, 88 
 
 Selenanthrene, 215 
 
 Selenium benzamide, 289 
 
 Seleno-phenols, 211 
 
 Seleno-phthalide, 348 
 
 Sellner, 485 
 Semicarbazone, 19 
 Semidin Transposition, 147 
 Senderens, 443 ' 
 Sesqui-terpenes, 546 
 Shikimic Acid, 474 
 Shikimino-ki, 411 
 Shikimol, 411 
 Silico-benzoic Acid, 170 
 Silico-diphenylimide, 93 
 Silico-tetraphenylamide, 93 
 Silver Benzamide, 281 
 
 Formanilide, 95 
 
 Sinalbin, 720 
 
 Sinapin sulphate, 720 
 
 Sinapinic Acid, 431 
 
 Sinigrin, 720 
 
 Slocum, 418 
 
 Sobrerol, 520 
 
 Sodium Acetanilide, 95 
 
 Sodium-acetic Ester, 43 
 
 Sodium-acetylene-tetracarboxylic Ester, 653 
 
 Sodium-benzaldehyde Sulphoxylate, 257 
 
 Sodium Benzamide, 281 
 
 Benzanilide, 282 
 
 Sodium-benzyl Iso-azotate, 248 
 Sodium Dibenzamide, 281 
 
 Formanilide, 94 
 
 Iso-p-nitro-diazo-benzol, 127 
 
 Sodium-phenate, 186 
 Sodium-phenol-o-carboxylic Acid, 192 
 Sodium-phenyl, 172 
 
 Carbonate, 192 
 
 Sodium-phenyl-hydrazin, 150 
 Sodium Salicylate, 192, 329 
 
 Salol, 330 
 
 Sozo-iodol, 207 
 Spiraea, 721 
 
 Spir&a ulmaria, 322, 328 
 Spiroytous Acid, 322 
 Stilbene, 27, 244, 258, 610 
 
 Alcohol Derivatives of, 619 
 
 Stilbene-carboxylic Acid, 621 
 Stilbene-diamine, 615 
 Stilbene Dibromide, 614 
 Stilbene-dicarboxylic Acid, 623 
 Stilbene-dichloride, 614 
 Stilbene-glycol Diacetate, 619 
 
 Dibenzoate, 619 
 
 Stilbene Hydrate, 613 
 Stilbene-methyl-ketone, 622 
 Stilbene-propionic Acid, 622 
 Stilbene-quinone, 612 
 Stilbene-succinic Acid, 623 
 Storax, 241, 413 
 Strecker, 123, 149 
 Styceric Acid, 384 
 Styracin, 420 
 Styrax Benzoin, 273 
 Styril-itaconic Acid, 441 
 Styril-succinic Acid, 441 
 Styrol, 30, 404 
 
 Dibromide, 369 
 
 Dichloride, 369 
 
 Oxide, 368 
 
 Styrol-pseudo-nitrosites, 404 
 Styrolene Alcohol, 367 
 Styrone, 413 
 Styryl-amine, 413 
 Styryl-methyl-carbinol, 414 
 Styryl-methyl-ketone, 416 
 Styryl-phenacyl-propionic Acid, 639 
 Suberane, 23 
 Suberane-acetic Acid, 25 
 Suberane-aldehyde, 24 
 Suberane-carboxylic Acid, 24 
 Suberane-i, i-dicarboxylic Acid, 24 
 Suberene, 23 
 Suberene-aldehyde, 24 
 
 Suberone, 24 
 Suberyl-alcohol, 23 
 Suberyl-glycolic Acid, 25 
 Suberyl-methylamine, 23 
 Suberylene-acetic Acid, 25 
 Succin-anile, 108 
 Succin-anilic Acid, 108 
 Succinic Phenyl-hydrazilic Ester, 163 
 Succino-rhodamin, 602 
 Succino-succinic Acid, 481 
 
 Diethyl Ester, 481 
 
 Succinyl-diphenyl-hydrazide, 163 
 Succinyl-phenyl-hydrazin, 163 
 Succinyl-succinic Acid, 363 
 Sulphamido-benzoic Acid, 313 
 Sulphanilic Acid, 177 
 Sulphanilide, 93 
 Sulphinic Acids, 179 
 Sulphinides, 314 
 Sulpho-anthranilic Acid, 308 
 Sulpho-benzide, 182, 251 
 Sulpho-benzoic Acids, 312, 313 
 
 Anhydride, 313 
 
 Anile, 314 
 
 Sulpho-benzol Disulphide, 181 
 
 Sulphide, 181 
 
 Sulpho-camphoric Acid, 543 
 Sulpho-camphylic Acid, 543 
 Sulpho-carbanile, 106 
 Sulpho-carbanile-amide, 101 
 Sulpho-carbanilide, 102 
 Sulpho-carbizin, 161 
 Sulpho-carbonimides, 314 
 Sulpho-chloride-benzoic Methyl Ester, 313 
 Sulpho-cinnamic Acids, 424 
 Sulpho-cyano-diazo-benzol Chloride, 125 
 Sulpho-hydrazin-cinnamic Acid, 424 
 Sulpho-o-phthalic Acid, 359 
 Sulpho-phosphazo-benzol Chloride, 93 
 Sulpho-salicylic Acid, 333 
 Sulpho-terephthalic Acid, 362 
 Sulphonation, 172 
 Sulphones, 180, 182 
 Sulphonic Acids, 172, 663 
 Sulphoxides, 181 
 Sulphurised Azo-dyes, 178 
 Suprarenin, 370 
 Sylvestrene, 495 
 Sylveterpine, 496 
 Sylveterpineole, 496 
 Syringa-aldehyde, 325 
 Syringa vulgaris, 721 
 Syringin, 721 
 
 Taneceium vulgar e, 510 
 Tanacetyl-alcohol, 511 
 Tannic Acids, 342 
 Tannin, 342 
 Taurine, 177 
 Teraconic Acid, 518 
 Teracrylic Acid, 518 
 Terebinic Acid, 517 
 Terephthalic Acid, 36, 361 
 
 Di-super-acid, 361 
 
 Teresantaric Acid, 526 
 Terpadienes, 486 
 Terpane, 486 
 Terpenes, 443, 484 
 Terpenogens, 487 
 Terpenylic Acid, 517, 518 
 Terpin 499 
 
 Hydrate, 499 
 
 Terpinene, 493 
 Terpinene-cineol, 500 
 Terpinene-nitrolamine, 493 
 Terpinene Nitrpsite, 493 
 Terpinene-terpin, 500 
 Terpineols, 502 
 Terpinolene, 492 
 Tertiary Amyl-phenol. 189 
 
 Butyl-phenol, 189 
 
 Phenyl-dialkylamines, 89 
 
 Tetra-ami do-benzol, 118 
 Tetra-amido-diphenyl-p-azo-phenylene, 115 
 
INDEX 
 
 757 
 
 Tetra-bromo-cyclo-butane, u 
 Tetra-bromo-fluorescein, 600 
 Tetra-bromo-phenol, 195 
 Tetra-bromo-stilbene-quinone, 612 
 Tetra-carboxylic Acids, 402 
 Tetra-chloro-acetoae, 48, 221 
 Tetra-chloro-cyclopentane, 16 
 Tetra-chloro-diketo-R-pentene, 18, 48 
 Tetra-chloro-gallem, 601 
 Tetra-chloro-p-quinone, 47 
 Tetra-chloro-quinone, 47 
 Tetra-chloro-stilbene-quinone, 612 
 Tetra-ethyl-benzol, 59 
 Tetra-ethyl-phenol, 189 
 Tetra-hydro-acenaphthene, 683 
 Tetra-hydro-aceto-phenone, 468 
 Tetra-hydro-benzaldehyde, 466 
 Tetra-hydro-benzoic Acids, 471 
 Tetra-hydro-benzols, 447, 448 
 Tetra-hydro-carveol, 498 
 Tetra-hydro-carvone, 506 
 Tetra-hydro-carvylamine, 504 
 Tetra-hydro-cprnicularic Acid, 635 
 Tetra-hydro-dicarboxylic Acids, 478 
 Tetra-hydro-diphenyl, 550 
 Tetra-hydro-eucarveol, 514 
 Tetra-hydro-eucarvone, 514 
 Tetra-hydro-fenchene, 526 
 Tetra-hydro-naphthalene, 685 
 
 Derivatives, 685 
 
 Tetra-hydro-naphthalene-dicarboxylic Acid, 687 
 Tetra-hydro-naphthoic Acids, 687 
 Tetra-hydro-naphthyl-phenol, 686 
 Tetra-hydro-naphthylamines, 685 
 Tetra-hydro-naphthylene, 684 
 
 Glycol, 686 
 
 Oxide, 686 
 
 Tetra-hydro-phenol, 454 
 Tetra-hydro-phenyl Fatty Acids, 472 
 Tetra-hydroquinone, 460 
 Tetra-hydro-terephthalic Acids, 479 
 Tetra-hydro-toluic Acids, 471 
 Tetra-hydro-toluols, 448 
 Tetra-methoxy-diphthalyl, 621 
 
 Tetramethyl-apionpl, 223 
 Tetra-methyl-benzidin, 5; 
 
 Tetra-methyl-benzoic Acids, 275 
 Tetra-methyl-benzol, 55 
 Tetra-methyl Derivative, 564 
 Tetra-methyl-diamido-benzile, 619 
 Tetra-methyl-diamido-azoxy-benzol, 140 
 Tetra-methyl-diamido-phenyl-oxanthrone, 709 
 Tetra-methyl-diamido-tetraphenyl-ethylene, 625 
 Tetra-methyl-2, 4-diketo-tetramethylene, 12 
 Tetra-methyl Dioxime, 12 
 Tetra-methyl-m-phenylene-diamine, 114 
 Tetra-methyl-mmx-diamido-azo-benzol, 145 
 Tetra-methyl-p-diamido-benzo-phenone, 90 
 Tetra-methyl-phenols, 189 
 Tetra-methyl Violet, 588 
 Tetra-methylene, i, 3 
 Tetra-methylene-carbinol, 1 1 
 Tetra-methylene-carboxyh'c Acid, 12 
 Tetra-methylene-cyclo-butane, ip 
 Tetra-methylene-i, i-dicarboxylic Acid, 12 
 Tetra-methylene-i, 2-dicarboxylic Acid ; 12 
 Tetra-methylene-i, 3-dicarboxylic Acid, 12 
 Tetra-methylene-diethyl-glycol, n 
 Tetra-methylene-i, 3-diglyoxylic Acid, 13 
 Tetra-methylene-dimethyl-carbiuol, n 
 Tetra-methylene Group, 10 
 Tetra-methylene-methyl-carbinol, n 
 Tetra-methylene-methylamine, 1 1 
 Tetra-methylene-methyl-ketone, 1 1 
 Tetra-methylene-i, 2-tetracarboxylic Acid, 12 
 Tetra-nitro-anisol, 197 
 Tetra-nitro-benzol, 71 
 Tetra-nitro-diphenyl-acetic Acid, 606 
 Tetra-nitro-naphthalenes, 659 
 Tetra-nitro-phenol, 197 
 Tetra-nitroso-benzol, 77 
 Tetra-oxy-benzo-phenone, 573 
 Tetra-oxy-biphenyls, 557 
 Tetra-oxy-cinnamic Acids, 431 
 Tetra-oxy-naphthalene, 671 
 Tetra-oxy-quinone, 230 
 
 Tetra-p-tolyl-hydrazin, 150 
 Tetra-p-tolyl-oxamide, 108 
 Tetra-phenyl-allene, 627 
 Tetra-phenyl-benzol, 562 
 Tetra-phenyl-butadiene, 633 
 Tetra-phenyl-croto-lactone, 634 
 Tetra-phenyl-cyclopentadiene, 16 
 Tetra-phenyl-diethylene-diamine, 615 
 Tetra-phenyl-dimethylene-quinone, 602 
 Tetra-phenyl-ethane, 624 
 Tetra-phenyl-ethane-dicarboxylic Acid, 627 
 Tetra-phenyl-ethylene, 624 
 Tetra-phenyl-ethylene Dichloride, 624 
 Tetra-phenyl-ethylene-glycol, 625 
 Tetra-phenyl-guanidin, 104 
 Tetra-phenyl-hexatriene, 640 
 Tetra-phenyl-hydrazin, 150 
 Tetra-phenyl-methane, 27, 602 
 Tetra-phenyl-octazone, 168 
 Tetra-phenyl-pentamethylene, 14 
 Tetra-phenyl-phenylene-diamines, 114 
 Tetra-phenyl-piperazin, 615 
 Tetra-phenyl-propinol, 630 
 Tetra-phenyl-silicpn, 171 
 Tetra-phenyl-succinic Acid, 627 
 Tetra-phenyl-tetramethylene-giycol, 633 
 Tetra-phenyl-tetrazone, 167 
 Tetra-phenyl-thio-urea, 102 
 Tetra-phenyl-urea, 100 
 Tetra-salicylide, 331 
 Tetra-thio-ethyl-quinone, 231 
 Tetra-tolyl-tetrazone, 167 
 Tetramido-anisol, 203 
 Tetramines, 118 
 Tetrazanes, 167 
 Tetrazenes, 167 
 Tetrazones, 139, 167 
 Tetroxy-terephthalic Ester, 483 
 Thebain, 689 
 Thianthrene, 214 
 
 Dioxide, 214 
 
 Monosulphone, 214 
 
 Tbio-acetanilide, 96 
 Thio-Acids, 280 
 Thio-aldo-aniline, 91 
 Thio-anilides, 96 
 Thio-anilines, 210 
 Thio-anisol, 211 
 Thio-benzaldehyde, 257 
 Thio-benzamide, 288 
 Thio-benzanilide, 289 
 Thio-benzo-hydroxamic Acid 294 
 Thio-benzo-phenone, 568 
 Thio-benzoic Acid, 280 
 Thio-borneol, 528 
 
 Thio-carbaminic a Phenyl-hydrazide ; 161 
 Thio-carbanilic Ethyl Ester, 101 
 Thio-carvacrol, 189, 208 
 Thio-cresol, 208 
 Thio-ctimarin, 428 
 Thio-cumazone, 251 
 Thio-cumo-thiazone, 251 
 Thio-derivatives of Phenol, 208 
 Thio-diglycol-anilic Acid, 98 
 Thio-diphenyl-amine, 92, 204, 211, 214 
 Thio-diphenyl-imides, 211 
 Thio-fonnanilide, 96, 97 
 Thio-isatin, 390 
 Thio-naphthene-quinone, 390 
 Thio-naphthols, 671 
 Thio-oxanilic Acid, 108 
 
 Thio-amide, 108 
 
 Thio-oxanilide, 108 
 Thio-phene, 633 
 Thio-pheno-quinone, 227 
 Thio-phenol, 208 
 Thio-phenol-sulphonic Acid, 178 
 Thio-phenyl-acetal, 208 
 Thio-phenyl-acetone, 208 
 Tbio-phthalic Anhydride, 356 
 Thio-phthaHde, 348 
 Thio-phthalimidin, 348 
 Thio-resprcin, 216 
 ThkHsalicylic Acid, 313, 332 
 Thio^salicylic-phenyl Ester, 333 
 Thio-urea Derivatives, 116 
 
758 
 
 INDEX 
 
 Thionin Dyes, 92 
 Thionyl-aniline, 93, 156 
 Thionyl-benzidin, 554 
 Thionyl-benzol, 181 
 Thionyl-phenyl-hydrazone, 156 
 Thionyl-o-bromaniline, 93 
 Thionyl-o-chloraniline, 93 
 Thionyl-o-iiitraniline, 93 
 Thionyl-o-toluidin, 93 
 Thuja-menthol, 513 
 Thuja-menthone, 513 
 Thujane, 511 
 Thujene, 511 
 Thujone, 510, 512 
 Thujone-oxime, 510 
 Thujyl-alcohol, 511 
 Thujylamine, 512 
 Thymo-dialdehyde, 346 
 Thymo-quinone, 228 
 Thymoil, 228 
 Thymol, 188, 505 
 Thymotic Acids, 335 
 Thy mo tin Alcohol, 316 
 Thymus vulgaris, 188 
 Tin-diphenyl Chloride, 171 
 Tin-tetraphenyl, 171 
 Tolane, 27, 613 
 
 Dichloride, 619 
 
 Tetrachloride, 618 
 
 Tolidins, 147, 554 
 Tolilic Acid, 607 
 Tolu Balsam, 56 
 Tolu-hydroquinone, 219 
 Tolu-quinol, 320 
 Tolu-quinone, 228 
 
 Dioxime, 233 
 
 Toluene-azo-naphthalene, 662 
 Toluic Acids, 274 
 
 Aldehydes, 256 
 
 Formaldehyde, 374 
 
 Toluidin, 85 
 
 Chlorohydrate, 82 
 
 Toluol, 30, 54, 55, 56 
 Toluol-disulphonic Acids, 176 
 Toluol, Higher Homologues of, 59 
 Toluol-sulphamide, 175 
 Toluol-sulphinic Acid, 181 
 Toluol-sulpho-chloride, 175 
 Toluol-sulphonic Acids, 175 
 Toluyl Chlorides, 279 
 Toluylene, 610 
 
 Blue, 239 
 
 Toluylene-diamido-sulphonic Acids, 178 
 Toluylene-diamines, 115 
 Toluylene-glycol, 614 
 Toluylic Acids, 31, 35, 56 
 Tolyl-acetic Acids, 276 
 Tolyl-aceto-nitriles, 286 
 Tolyl-alcohol, 30 
 Tolyl-aldehyde, 30 
 Tolyl-azo-benzoic Acid, 312 
 Tolyl-glyoxylic Acid, 390 
 Tolyl-hydrazin, 150 
 Tolyl-hydroxylamine, 78 
 Tolyl Isocyanate, 105 
 Tolyl-isocyanide, 97 
 Tolyl-methyl-triazene, 136 
 Tolyl-nitro-methane, 245 
 Tolyl-phenyl-hydrazin. 146 
 Tolyl-phosphoro-chloride. 169 
 Tolyl-semicarbazide, 160 
 Tolyl-sulphaminic, 93 
 Tolyl-trianilido-phosphonium Chloride, 169 
 Triaceto-phloro-glucin, 347 
 Triacetyl-benzol, 347 
 Triacetyl-gallic Acid, 341 
 Triacid Menthane Alcohols, 500 
 Trialkyl-benzamidin, 290 
 Triamido-azo-benzol, 145 
 Triamido-benzoic Acid, 310 
 Triamido-benzol, 79 
 Triamido-diazp-benzol, 114 
 Triamido-mesitylene, 118 
 Triamido-phenol, 202 
 Triamido-toluol, 118 
 Triamido-triphenyl-acetic Nitrile, 609 
 
 Triamido-triphenyl-carbinols. 584 
 Triamines, 118 
 
 Triamino-triphenyl-methanes, 579 
 Trianisyl-carbinol, 593 
 Trianisyl-methane, 590 
 Trianthraquinone-di-imides, 712 
 Trianthrimides, 712 
 Tribenzal-diamine, 257 
 Tribenzamide, 281 
 Tribenzo-nitrile Oxide, 295 
 Tribenzoyl-hydroxylamine, 294 
 Tribenzoyl-methane, 630 
 Tribenzyl-amine, 246 
 Tribenzyl-carbinol, 628 
 Tribenzyl-sulphinic Chloride, 244 
 Tribenzyl-sulphinic Iodide, 244 
 Tribiphenyl-methyl, 627 
 Tribromaniline, no 
 Tribromo-aceto-benzoic Acid, 402 
 Tribromo-benzol-diazo-cyanide, 128 
 Tribromo-cyclo-butane, 10 
 Tribromo-fluorene, 696 
 Tribromo-hemimellithol, 66 
 Tribromo-mesitylene, 66 
 Tribromo-phenyl-nitramine, 121 
 Tribromo-pseudocumol, 66 
 Tribromo-reso-quinone, 558 
 Tricarboxylic Acids, 364, 402 
 Trichlor-ethylidene-diphenyl-diarnine, 90 
 Trichloraniline, no 
 Trichlor-ethylene, 47 
 Trichloro-aceto-benzoic Acid, 402 
 Trichloro-acetyl-pentachloro-butyric Acid, 48 
 Trichloro-cyclopentane, 15 
 
 Trichloro-cyclo-pentene-dioxy-carboxylic Acid, 21 
 Trichloro-naphthalenes, 659 
 Trichloro-phenanthrene, 689 
 Trichloro-pheno-malic Acid, 46 
 Trichloro-phenyl-nitramine, 121 
 Trichloro-phosphanile, 93 
 Trichloro-quinone Chlorimine, 235 
 Tricyclene, 525 
 
 Tricyclene-carboxylic Acid, 522 
 Tricyclo-trimethylene Benzol, 695 
 Triethyl-benzol, 59 
 Triethyl-phenyl Silicide, 170 
 Trihydrazin, 589 
 Tri-iodaniline, no 
 Tri-iodo-2-chloro-benzol, 61 
 Triketo-hydrindene, 649 
 
 Triketo-pentamethylene-3, 5-dicarboxylic Ester, 22 
 Trimellitic Acid, 365 
 Trimesic Acid. 364 
 Trimesinic Acid, 57 
 Trimethoxy-benzaldehyde, 325 
 Trimethyl-benzoic Acids, 275 
 Trimethyl-benzols, 55, 57 
 Trimethyl-brasilin, 726 
 Trimethyl-brasilone, 726 
 Trimethyl-cyclo-hexane, 446 
 Trimethyl-cyclopentanone, 17 
 Trimethyl-dehydro-brasilone, 726 
 Trimethyl-dihydro-resorcin, 460 
 Trimethyl-ethyl-benzol. 59 
 Trimethyl-homogallic Acid, 342 
 Trimethyl - keto - pentamethyleiie - dicarboxylic 
 
 Ester, 21 
 Trimethyl-oxy-tetrahydro-naphthylene-ammonium 
 
 Hydroxide, 686 
 Trimethyl-phenyl-allene, 408 
 Trimethyl-quinol, 320 
 Trimethyl-trimethylene, 7 
 Trimethyl-triphenyl-para-rosanilin. 589 
 Trimethylene, i, 7 
 Trimethylene-aldehyde, 8 
 Trimethylene Benzamidin, 290 
 
 Bromide, 7 
 
 Trimethylene-carbanilide, 100 
 Trimethylene-carbinol, 7 
 Trimethylene-carboxylic Acids, 8 
 Trimethylene- 1, i-dicarboxyh'c Acid, 8 
 Trimethylene-i, 2 -dicarboxylic Acid, 9 
 Trimethylene-diethyl-carbinpl, 8 
 Trimethylene-dimethyl-carbinol, 8 
 Trimethylene-diphenyl-diamine, 90 
 Trimethylene-ethyl-carbinol, 8 
 
INDEX 
 
 759 
 
 Trimethylene Group, 7 
 Trimethylene-isopropyl-carbinol, 8 
 Trimethylene-methyl-ethyl-carbinol , 8 
 Trimethylene-methylainine, 7 
 Trimethylene-phenyl-urea, 100 
 Trimethylene-phenylimine, 90 
 Trimethylene- 1, 2-tetracarboxylic Acid, 9 
 Trimethylene-i, 2, 3-tetracarboxylic Acid, 9 
 Trimethylene-i, 2-tricarboxylic Acid, 9 
 Trimethylene-i, 2. 3-tricarboxylic Acid, 9 
 Trimethylene-tricyano-tricarboxylic-acid Ester, 10 
 Trimolecular Diphenyl-silicon, 171 
 Trinaphthyl-carbinol, 682 
 Trinaphthylene-benzol, 683 
 Trinitraniline, in 
 Trinitro-azo-benzols, 142 
 Trinitro-azoxy-benzols, 140 
 Trinitro-benzaldehyde, 262 
 Trinitro-benzoic Acid, 299 
 Trinitro-benzols, 70 
 Trinitro-chloro-benzol, 72 
 Trinitro-chloro-benzol-picryl-chloride, 72 
 Trinitro-5-chloro-toluol, 74 
 Trinitro-diphenyl-sulphone, 183 
 Trinitro-ethyl-benzol, 73 
 Trinitro-hydranthranol, 705 
 Trinitro-m-xylol 73 
 Trinitro-mesitylene, 73 
 Trinitro-naphthalenes. 659 
 Trinitro-nitroso-benzol, 76 
 Trinitro-p-xylol, 73 
 Trinitro-phenols, 196 
 Trinitro-phenyl-carbinol, 582 
 Trinitro-phenyl-hydroxylamine, 78 
 Trinitro-phenyl-malonic Ester, 396 
 Trinitro-phenyl-methane, 577 
 Trinitro-phenyl-nitramine. 121 
 Trinitro-phenyl-phenyl-amine, 112 
 Trinitroso-phloroglucin, 222 
 Trinitro-pseudocumol; 73 
 Trinitro-tolupl, 72 
 Trinitro-v-trimethyl-benzol, 73 
 Trinitro-xylidine, in 
 Trinitro-xylyl-phenyl-amine, 112 
 Trioxy-alcohol Acid's, 386 
 Trioxy-anthraquinones, 716, 717 
 Trioxy-anthraquinone-carboxylic Acid, 717 
 Trioxy-aurin, 594 
 Trioxy-benzoic Acids, 340 
 Trioxy -benzol, 30 
 Trioxy-cinnamic Acids, 431 
 Trioxy-dicarboxylic Acids, 363 
 Trioxy-hexahydro-cymol, 500 
 Trioxy-methyl-anthraquinone, 717 
 Trioxy-naphthalenes, 671 
 Trioxy-phenanthrene, 690 
 Trioxy-trinaphthyl-methane, 682 
 Triphenyl-acetaklehyde, 608 
 Triphenyl-acetic Acid, 608 
 Triphenyl-acrylic Ester, 624 
 Triphenyl-acyl-methyl-amine, 373 
 Triphenyl-arsin, 170 
 Triphenyl-benzols, 562 
 Triphenyl-biuret, too 
 Triphenyl-bromo-ethanone, 624 
 Triphenyl-bromo-methane, 580 
 Triphenyl-butadiene, 633 
 Triphenyl-carbinol, 580 
 
 Chloride, 580 
 
 Triphenyl-chloro-carbamidin, 100 
 Triphenyl-chloro-methane, 580 
 Triphenyl-croto-lactone, 634 
 Triphenyl Cyanurate, 105 
 Triphenyl-cyanuro-triamide, 107 
 Triphenyl-cyclopentadiene, 16 
 Triphenyl-dimethyl-pentamethylene, 14 
 Triphenyl-ethane, 623 
 Triphenyl-ethanol, 624 
 Triphenyl-ethanone, 623 
 Triphenyl-ethyl Silicide, 170 
 Triphenyl-ethylene, 623 
 Triphenyl-ethylene-glycol, 623 
 Triphenyl-glutaric Acid, 632 
 Triphenyl-guanidin, 104 
 Triphenyl-hydranthracene, 709 
 Triphenyl-hydranthranol, 709 
 
 Triphenyl-hydrazin, 150 
 Triphenyl-indene, 645 
 Triphenyl-iodo-methane, 580 
 Triphenyl Isocyanurate, 105 
 Triphenyl-isomelamine, 107 
 Triphenyl-melamine, 107 
 Triphenyl-methane, 27, 577 
 Triphenyl-methane-azo-benzpl, 581 
 Triphenyl-methane-carboxylic Acids, 594 
 Triphenyl-methane Group, 576 
 Triphenyl-methane-hydrazo-benzol, 581 
 Triphenyl-methyl, 14 
 Triphenyl-methyl-amine, 581 
 Triphenyl-methyl-aniline, 581 
 Triphenyl-methyl-ethane, 624 
 Triphenyl-methyl-hydrazin, 581 
 Triphenyl-methyl-sUicide, 170 
 Triphenyl-nitro-methane, 626 
 Triphenyl-nitroso-methane, 626 
 Triphenyl-oxy-ethanone, 624 
 Triphenyl-para-rosanilin, 539 
 Triphenyl-phosphine, 169 
 
 Oxide, 169 
 
 Triphenyl-propio-phenone, 629 
 Triphenyl-propionic Acid, 624 
 Triphenyl-pseudo-thio-urea, 103 
 Triphenyl-rosaniline, 92 
 Triphenyl-rosanilin Hydrochloride, 589 
 Triphenyl-semi-carbazide, 160 
 Triphenyl-silicane, 171 
 Triphenyl-siKcp-chloride, 170 
 Triphenyl-stibin, 170 
 
 Sulphide, 170 
 
 Triphenyl-tetrazolium Hydroxide, 292 
 Triphenyl-thio-urea, 102 
 Triphenylamine, 79, 92 
 Triphenylene, 695 
 Triquinoyl, 231, 460 
 Triresorcin, 215 
 Trithio-vanillin, 324 
 Tritoluol-sulphonamide, 175 
 Tritolyl-amine, 92 
 Trixis pipitzahuac, 231 
 Tropic Acid, 380 
 Tropilidene, 23 
 
 Tropilidene-carboxylic Acids, 24 
 Tropafolum majus, 286, 720 
 Truxillic Acid, 421 
 Tuberosa, 302 
 Turpentine, 515 
 Tyrosin, 381 
 
 UMBELLIC Acid, 430 
 Umbelh'ferone, 430 
 Umbellulone, 513 
 Urea Chlorides, 99 
 Urethano-phenyl-aceto-nitrile, 379 
 Usnea, 727 
 Usnic Acid, 217, 727 
 Uvitinic Acid, 57, 360 
 
 VALENCES, Residual, 42 
 Valero-hydroquinone, 327 
 Vanillic Acid, 337 
 Vanillin, 324 
 Vanillin-oxime, 324 
 VanUlyl Alcohol, 321 
 Veratric Acid, 338 
 Veratroyl-carboxylic Acid, 390 
 Vesuvine, 145 
 Vinaconic Acid, 8 
 Vinyl-benzoic Acid, 418 
 Vinyl-benzol, 30, 404 
 Vinyl-naphthalin, 658 
 Vinyl-phenol, 409 
 Vinyl-phenyl-acetic Acid, 418 
 Vinyl-pyro-catechin, 410 
 Vinyl-trimethylene, 7 
 Violanthrenes, 719 
 Virianin, 723 
 Viridiflora, 727 
 Vulpic Acid, 637 
 
760 
 
 INDEX 
 
 WAGNER, 485, 516, 523 
 Wallach, 485 
 Wanklyn, 586 
 Water Blue, 589 
 Werner, 259 
 Winther, 669 
 Wohler, 255 
 Woskresensky, 226, 231 
 Wurster's Red. 234 
 
 XANTHOGEN-ANILIDE, 101 
 Xanthone, 330, 595 
 Xylenols, 187 
 Xylidic Acid, 361 
 Xylidins, 86 
 Xylo-quinone, 228 
 Xylol, 30, 54, 55, 56 
 Xylol-disulphonic Acids, 176 
 Xylol Hexachloride, 447 
 Xylol-2-sulphonic Acid, 175 
 
 Xylol-3-sulphonic Acid, 175 
 Xylol-4-sulphonic Acid, 175 
 Xylorcin, 217 
 Xylyl-acetic Acid, 276 
 Xylyl-hydrazin, 150 
 Xylyl-hydroxylamine, 78 
 Xylylene Alcohols, 344 
 Xylylene-diamine, 115, 344 
 Xylylene Oxide, 344 
 Sulphide, 344 
 
 Sulpho-hydrates, 344 
 
 Tetrabromide, 346 
 
 Xylylenimine, 344 
 Xylylol Tetrachlorides, 346 
 
 YELLOW Corallin, 593 
 
 ZlNCKE, 46 
 
 Zingiberene. 547 
 Zulkowsky, 586 
 
 END OF VOL. II. 
 
 PRINTED IN GREAT BRITAIN BY NEILL AND CO., LTD., EDINBURGH. 
 
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