key: cord-0036837-2f2yqsd2 authors: Mizuhara, Tsukasa title: Structure–Activity Relationship Study of PD 404182 Derivatives for the Highly Potent Anti-HIV Agents date: 2013-10-08 journal: Development of Novel Anti-HIV Pyrimidobenzothiazine Derivatives DOI: 10.1007/978-4-431-54445-6_3 sha: 6de5ab8f045722753f4f71dbafe8b4f711e847ac doc_id: 36837 cord_uid: 2f2yqsd2 Using facile synthetic approaches to pyrimido[1,2-c][1,3]benzothiazin-6-imines and related tricyclic derivatives, the parallel structural optimizations were investigated for the central 1,3-thiazin-2-imine core, the benzene part, and the cyclic amidine part of PD 404182. Replacement of the 6-6-6 pyrimido[1,2-c][1,3]benzothiazin-6-imine framework with 5-6-6 or 6-6-5 derivatives led to a significant loss of anti-HIV activity, and introduction of a hydrophobic group at the 9- or 10-positions improved the potency. The most potent PD 404182 derivative exerts anti-HIV effects at an early stage of viral infection including binding and fusion. Lawesson's reagent led to formation of the thiocarbonyl derivative 8. Since no hydrolysis of the carbonyl or thiocarbonyl group of compound 7 or 8 for construction of the 2-aminoquinazoline structure in 9 occurred, an alternative approach starting from 2-aminobenzyl alcohol 12 was used for the synthesis the 2-aminoquinazoline derivative 9 (Scheme 3.2). After protection and PCC oxidation of 12, oxidative amidination [3] provided 2-(p-tosylamino)phenyltetrahydropyrimidine (14) . Deprotection followed by BrCN-mediated cyclization of 14 provided the expected 2-aminoquinazoline derivative 9. To synthesize pyrimido [1,2-c] [1, 3] benzothiazine derivatives 1 and 11 (Scheme 3.1), compound 2 was exposed to CS 2 in the presence of Cu(OAc) 2 to directly afford a pyrimido [1,2-c] [1, 3] benzo-thiazine-6-thione scaffold 10. Hydrolysis of the thiocarbonyl group in 10 followed by treatment with BrCN or triphosgene provided 6-imino or 6-oxo derivatives (1 or 11) , respectively. Pyrimido [1,2-c] [1, 3] thiazin-6-imine derivatives 25-27 with a series of fused benzene and heterocycles were prepared by consecutive heterocumulene addition and S N Ar reactions (Scheme 3.3). These reactions provide easy access to the construction of the 1,3-thiazin-2-imine derivatives more efficiently (Chap. 2.2) than the diversity-oriented C-H functionalization approach (Chap. 2.1). The oxidative amidination of aromatic aldehydes 15-17 with an accessory functional group afforded the corresponding 2-phenyltetrahydropyrimidine derivatives [18] [19] [20] . The pyrimido [1,2-c] [1, 3] thiazine-6-thione scaffold 21 was obtained by additions of 18f,g,i or 20s,t,u to CS 2 followed by S N Ar-type C-S bond formation. The desired 6-imino derivatives 25f,g,i and 27s,t,u were obtained via hydrolysis of the thiocarbonyl group of 21 followed by BrCN treatment. Alternatively, reactions of other 2-phenyltetrahydropyrimidines 18-20 with tert-butyl isothiocyanate afforded N-(t-Bu)-protected thiazinimine derivatives 22-24, which were treated with TFA to provide the expected products 25-27. The intermediates 22e, 22k, and 23k were subjected to further manipulations to obtain the functionalized derivatives (Scheme 3.4) . The nitro group of 22e was reduced by hydrogenation to form the 9-amino derivative 28. Alkylation of 28 afforded the 9-(N-methylamino) derivative 22b (eq 1). The 9-acetamide derivative 22c was obtained by treatment of 28 with acetic anhydride (eq 2). Sandmeyer reaction of 28 gave the 9-azide derivative 22p (eq 3). Me 2 N-and MeO-substituted derivatives (22a, 23a, and 23f) were obtained by Me 2 NH-mediated N-arylation [4, 5] of the 9-bromo 22k and 10-bromo derivatives 23k, and NaOMe-mediated Reagents and conditions (a) p-TsCl, pyridine, CHCl 3 , rt; (b) PCC, silica gel, CH 2 Cl 2 , rt, 80 % [2 steps (a, b) ]; (c) 1,3-propanediamine, I 2 , K 2 CO 3 , t-BuOH, 70°C, 98 %; (d) conc. H 2 SO 4 , 100°C, then NaOH, H 2 O; (e) BrCN, EtOH, reflux, 66 % [2 steps (d, e)] Ullmann coupling [6] of 23k, respectively (eq 4 and 7). The 9-acetyl derivative 22d was obtained by Heck reaction [7] of 22k with 2-hydroxyethyl vinyl ether (eq 5). Other derivatives with a variety of functional groups (22, 23, 29, and 30) were synthesized by Suzuki-Miyaura coupling reactions [8, 9] of 22k and 23k with boronic acids or their pinacol esters (eq 6 and 7). Final deprotection of the tert-butyl group in 22, 23, 29, and 30 afforded the 9-or 10-substituted pyrimido [1,2-c] [1, 3] benzothiazine derivatives 25, 26, 31, and 32, respectively. Benzo [e] [1, 3] thiazine derivatives with various ring-sized and/or modified cyclic amidine moieties 36 were synthesized using standard synthetic methods (Scheme 3.5) . Oxidative addition using a number of diamines 33 proceeded efficiently to form five-or six-membered rings (34a-d). The same reaction for the seven-membered amidine (34e) was incomplete, but purification of the Boc-protected amidine 37 followed by subsequent deprotection of the Boc group gave the pure seven-membered amidine 34e. The resulting amidines were converted to cyclic-amidine-fused benzo [e] [1, 3] thiazin-2-imines 35 via tert-butyl isothiocyanate addition and an S N Ar reaction. TFA-mediated deprotection gave the expected derivatives 36. The synthesis of the spiropyrimidine-fused derivatives started with the dialkylation of malononitrile with dihaloalkanes (38, 39, or 41, Scheme 3.6) . BH 3mediated reduction of the alkylated malononitriles (42-44) followed by oxidative amidination with 4-bromo-2-fluorobenzaldehyde gave the 2-phenyl-1,4,5,6-tetrahydropyrimidine derivatives (45-47) . Subsequent exposure of compounds 45-47 to tert-butylisothiocyanate provided the tetracyclic compounds 48, 50, and 52a. Deprotection of the tert-butyl groups in compounds 48, 50, and 52a afforded the desired spiropyrimidine-fused benzothiazinimine derivatives (49, 51, and 53a) . The substitution of the p-methoxybenzyl (PMB) group in compound 53a was also attempted (Scheme 3.6). The treatment of compound 52a with methyl chloroformate or acetyl chloride directly provided derivatives 52b and 52c, respectively. A two-step procedure, including the removal of the PMB group by treatment with 1-chloroethyl chloroformate followed by modification with mesyl chloride (MsCl) or trimethylsilyl isocyanate (TMSNCO) was used for the synthesis of the derivatives 52d and 52e, respectively, because the reaction of compound 52a with MsCl and TMSNCO failed. Deprotection of the tert-butyl group in 52b-e afforded the respective N-substituted derivatives 53b-e. SARs of the central heterocyclic core in pyrimido [1,2-c] [1, 3] benzothiazines were carried out. Initially, the structural requirements of the 1,3-thiazin-2-imine core substructure in 1 (PD 404182) for anti-HIV activity were investigated (Table 3 .1). The antiviral activities against the HIV-1 IIIB strain were evaluated using the MAGI assay [10] . Substitution of the imino group in 1 with a carbonyl group (11) resulted in a significant decrease in anti-HIV activity (EC 50 = 8.94 lM). Pyrimido [1,2-c] [1, 3] benzoxazines (4) (5) (6) , pyrimido [1,2-c] quinazolines (7) (8) (9) , and pyrimido [1,2-c] [1, 3] benzothiazine-6-thione (10) , in which the 1-sulfur and/or 2-imino groups in 1 were modified, showed no activity. These results suggested that both the 1-sulfur atom and the 2-imino group are indispensable functional groups for the inhibitory activity against HIV infection, and may be involved in potential interactions with the target molecules. A series of derivatives with modification of the benzene substructure in the pyrimido [1,2-c] [1, 3] benzothiazine were evaluated for anti-HIV activity (Table 3 .2). The addition of positively charged N,N-dimethylamino (25a) and Nmethylamino groups (25b) at the 9-position significantly decreased the anti-HIV activity. The 9-acetamide group (25c), which has hydrogen bond donor/acceptor abilities, also attenuated the bioactivity. The acetyl (25d) and nitro (25e) groups, with hydrogen acceptor properties, induced slight decreases in the anti-HIV activity. In contrast, derivatives with less-polarized substituents (25f-o and 25q) at this position generally reproduced the potent anti-HIV activity of 1. In terms of the electron-donating or -withdrawing properties of the substituent groups on the benzene substructure, good correlations were not observed. For example, the electron-donating methoxy (25f), methyl (25g), and n-butyl groups (25h), and the electron-withdrawing fluoro (25i) and trifluoromethyl groups (25j) exhibited similar anti-HIV activities (EC 50 = 0.44-0.57 lM), indicating that the antiviral activity is independent of the electronic state of the 1,3-benzothiazin-2-imine core in forming potential p-stacking interaction(s) with the target molecules. Among Scheme 3.4 Synthesis of 9-or 10-substituted pyrimido [1,2-c] [1, 3] benzothiazin-6-imine derivatives. Reagents and conditions (a) H 2 , 10 % Pd/C, EtOH, rt, 88 %; (b) NaOMe, (CH 2 O) n , MeOH, reflux, then NaBH 4 , 91 %; (c) TFA, MS4Å, CHCl 3 , reflux, 37-95 %; (d) Ac 2 O, DMAP, Et 3 N, CH 2 Cl 2 , rt,[99 %; (e) NaNO 2 , AcOH, H 2 O, 0°C, then NaN 3 , 70 %; (f) Pd(OAc) 2 , t-Bu 3 P, NHMe 2 , THF, KOt-Bu, toluene, reflux, [99 %; (g) 2-hydroxyethylvinylether, Pd(OAc) 2 , 1,3-bis(diphenylphosphino)propane, K 2 CO 3 , H 2 O, 90°C, 13 % [2 steps (g, c) ]; (h) R-B(OH) 2 or R-Bpin, Pd(PPh 3 ) 4 , PdCl 2 (dppf) Á CH 2 Cl 2 , K 2 CO 3 , toluene or 1,4-dioxane, EtOH, H 2 O, reflux, 62-96 %; (i) n-BuB(OH) 2 , Pd 2 (dba) 3 , P(t-Bu) 3 , CsCO 3 , 1,4-dioxane, reflux, 6 % (for 22h); (j) Pd(Pt-Bu 3 ) 2 , NHMe 2 , THF, KOt-Bu, toluene, 170°C, 67 % (for 23a); (k) CuBr, NaOMe, MeOH, DMF, reflux, 40 % (for 23f) the hydrophobic substituents at this position, bromo (25k), phenyl (25l), vinyl (25m), styryl (25n), and pentenyl groups (25o) induced inhibitory activity two or three times greater than that of 1 (EC 50 = 0. 18-0.25 lM) . Modification with photoreactive azido (25p) and benzoylphenyl groups (25q) maintained the inhibitory activity; these could be used as probe molecules to identify the target molecule(s) of 1 [11] [12] [13] . Similar SARs were observed for modification at the 10-position of pyrimido [1,2-c] [1, 3] benzothiazine. Addition of positively charged N,N-dimethylamino (26a) and polarized nitro groups (26e) reduced the anti-HIV activity (EC 50 = 2.12 and 3.00 lM, respectively). Hydrophobic groups including methoxy (26f), methyl (26g), bromo (26k), phenyl (26l), vinyl (26m), and 4-benzoylphenyl (26q) had favorable effects on the bioactivity (EC 50 = 0.24-0.67 lM), suggesting potential hydrophobic interactions of these additional functional groups with the target molecule(s). Further miscellaneous modifications of benzothiazine substructure were also investigated ( Table 3. 2). The naphtho [2,3-e] [1, 3] thiazine derivative 27r, with a 9,10-fused benzene, exhibited anti-HIV activity equipotent to that of the parent 1 (EC 50 = 0.56 lM). A 6-fold decrease in the anti-HIV activity of the pyridinefused pyrido [3,2-e] [1, 3] thiazine derivative (27s) was observed (EC 50 = 2.55 lM). In addition, introduction of 8-bromo (27k) and 8,9-fused benzene (27t, naphtho[2,1-e] [1, 3] thiazine) substituents on benzothiazine resulted in a loss of activity, suggesting that modification at the 8-position was inappropriate for favorable interactions with the target molecule(s). The 11-fluoro derivative 27i and thiophene-fused 27u, the latter of which has 5-6-6 framework (thieno [2,3-e] [1, 3] thiazine), exhibited four times lower and no inhibitory potencies, respectively. On the basis of the above SAR data for the benzene substructure in 1 (PD 404182), the author expected that introduction of a hydrophobic group at the pyrimido [1,2-c] [1, 3] benzothiazine 9-position would be the most promising. The next optimization to obtain more potent derivatives was therefore focused on modification of the benzothiazine scaffold at position 9 with an additional aryl group (Tables 3.3, 3.4) . The author initially examined substituent effects at the para-position on the 9phenyl group of compound 25l. Modification with methoxycarbonyl (31a), cyano (31b), nitro (31c), and trifluoromethyl (31d) groups slightly reduced the anti-HIV activity (EC 50 = 0.44-0.81 lM), whereas a significant decrease in the anti-HIV activity was observed for a carbamoyl group (31e), with hydrogen bond donor/ acceptor properties (EC 50 = 8.71 lM). The hydrophobic methoxy (31f, Similar effects as a result of modification at the meta-position of the 9-phenyl group were observed. Addition of electron-withdrawing methoxycarbonyl (31i), cyano (31j), and nitro (31k) (EC 50 = 0.39-1.26 lM) groups resulted in slight decreases in anti-HIV activity. Hydrophilic (1-hydroxy)ethyl (31l, EC 50 = 1.19 lM), acetylamino (31m), mesylamino (31n), and hydroxyl (31o, EC 50 = 2.62 lM) groups induced reduction or loss of anti-HIV activity. In contrast, a methoxy group (31p) improved the inhibitory activity (EC 50 = 0.15 lM). The more hydrophobic isopropoxy group (31q) maintained the anti-HIV activity of 25l (EC 50 = 0.32 lM), whereas a phenyl group (31r) decreased the inhibitory activity (EC 50 = 1.35 lM). Similar anti-HIV activities of the ortho-methoxy (31s) and ortho-phenyl group (31t) to that of 25l were exhibited (EC 50 = 0.41 and 0.32 lM, respectively), suggesting that the twisted conformations of these 9-phenyl PD 404182 derivatives might not prevent the interaction with the target molecule(s). In order to develop more potent anti-HIV agents, the author subsequently attempted bis and tris modifications of the 9-phenyl group in 25l. Modification with 9-(3,4-dimethoxy)phenyl (31u, EC 50 = 0.27 lM) or 9-(3,4,5-trimethoxy)phenyl (31v, EC 50 = 0.25 lM) groups of the pyrimido [1,2-c] [1, 3] benzothiazine scaffold did not alter the bioactivity. Cl-modified derivatives 31w and 31x exhibited similar potencies (EC 50 = 0.32 and 0.48 lM, respectively). Since the 9-(2-naphthyl)-modified analog (32a) exhibited slightly more potent anti-HIV activity (EC 50 = 0.20 lM) compared with that of the 1-naphthyl congener (32b, EC 50 = 0.39 lM, Table 3 .4), the author further investigated modifications with a variety of 3,4-fused phenyl groups. Compound 32c with a 5.12 ± 1.28 a EC 50 values represent the concentration of compound required to inhibit the HIV-1 infection by 50 % and were obtained from three independent experiments b Cytotoxicity was observed at 10 lM 1,3-dioxolane-fused phenyl group displayed activity twice as potent as that of compound 25l (EC 50 = 0.15 lM), whereas the 1,4-dioxane-fused derivative 32d and quinolin-6-yl derivative 32e exhibited less favorable effects (EC 50 = 0.26 and 0.25 lM, respectively). Introduction of an indolyl group (32f and 32g) resulted in no anti-HIV activity and unexpected cytotoxicity. Substitutions of the 9-phenyl group by various heterocyclic substructures were also investigated. Six-membered heterocycles such as pyridine (32h and 32i) slightly reduced the anti-HIV activity (EC 50 = 0.45 and 0.54 lM, respectively). The five-membered furan (32j), benzofuran (32k), thiophene (32l), benzothiophene (32m), and pyrazole (32n) derivatives maintained the original activity of 25l (EC 50 = 0.20-0.42 lM). Notably, reduced anti-HIV activity was observed for the basic imidazole derivative (32o, EC 50 = 5.12 lM). A SAR study of the top-right cyclic amidine substructure was carried out. The five-membered dihydroimidazole derivative 36a had no anti-HIV activity (Table 3 .5), suggesting that the five-membered ring may impair the critical interactions with the target molecule(s) via its small-sized ring strain or indirect effects on the thiazinimine core with a possibly altered conformation. Similarly, compound 36b with the phenyl-fused dihydropyrimidine substructure showed lower inhibitory activity (EC 50 = 3.78 lM). Appending one or two methyl groups on the six-membered pyrimidine (36c and 36d) induced 1.5-to 2-fold higher inhibitory potencies (EC 50 = 0.35 and 0.24 lM, respectively) compared with that of the parent compound 1. In addition, compound 36e with a seven-membered tetrahydro-1,3-diazepine substructure exhibited similar anti-HIV activity to that of 1 (EC 50 = 0.31 lM). Above optimization studies indicated that the introduction of a hydrophobic group on the cyclic amidine substructures effectively improved the antiviral activity (compound 36c-e) by generating a potentially favorable interaction(s) with the target molecule(s). Therefore, anti-HIV activities of several spiropyrimidine fused derivatives were evaluated (Table 3 .6). 1 Cyclohexane (49) and Nmethoxycarbonylpiperidine (53b) derivatives exhibited the similar levels of anti-HIV activity (EC 50 = 0.25 and 0.44 lM, respectively) to that of the dimethyl derivative 36d (EC 50 = 0.24 lM). In contrast, the tetrahydropyran (51) and N-(pmethoxybenzyl)piperidine (53a) derivatives exerted inhibitory activities that were 5-7-fold lower (EC 50 = 1.73 and 1.45 lM, respectively) than that of the parent dimethyl derivative 36d. The N-acetyl-(53c), N-methanesulfonyl-(53d), and Ncarbamoyl-(53e) piperidine derivatives also provided reduced levels of antiviral activity (EC 50 = 1.81 to [10 lM) . With this in mind, the N-alkoxycarbonyl piperidine group was identified as a linkage for the introduction of additional functional group(s) to PD 404182 with potent anti-HIV activity (53b). To investigate the mechanism of action of PD 404182 derivatives, a time of drug addition study was carried out (Fig. 3.3) . In this experiment, the anti-HIV activity profiles of 1 and its derivatives 32c were compared with those of wellknown anti-HIV agents such as an adsorption inhibitor (DS 5000) [14] , fusion inhibitor (enfuvirtide) [15] [16] [17] , NRTI (AZT) [18] , NNRTI (nevirapine) [19] , and integrase inhibitor (raltegravir) [20] . After inoculation of HeLa-CD4/CCR5-LTR/ b-gal cells with HIV-1 IIIB , each anti-HIV-1 drug was added at a 90 % inhibitory effect concentration at the indicated time points. The inhibitory effects on the infection were determined by counting the blue cells 48 h later. This investigation revealed that compound 1 (PD 404182) had an inhibitory profile in the early stage of viral infection similar to those of DS 5000 and enfuvirtide ( Fig. 3 .3). Identical profiles were observed for 1 and the most potent derivative 32c, indicating that the bioactivity profile is independent of the appended functional group(s). To gain additional insights into the mechanism of action of PD 404182 derivatives, the antiviral activities against other HIV subtypes were evaluated (Table 3 .7). Compound 1 was effective against not only HIV-1 IIIB but also other two HIV-1 strains (HIV-1 NL4-3 and HIV-1 BaL ) with similar potency. Both HIV-1 IIIB and HIV-1 NL4-3 strains utilize CXCR4 as a coreceptor for entry, while HIV-1 BaL strain does CCR5, indicating that chemokine receptors CXCR4 and CCR5 are not the molecular targets of PD 404182 derivatives. The similar level of antiviral activity of 1 against HIV-2 (HIV-2 EHO and HIV-2 ROD ), which is mainly distributed in West Africa, was observed. Highly potent inhibitory activities of derivatives 32c and 36d 2 against these HIV strains were observed, as in the case of the SAR study of the HIV-1 IIIB strain discussed above. It has been well-known that NNRTIs are not effective against HIV-2, highlighting that PD 404182 derivatives do not act as NNRTIs. Although PD 404182 derivatives and enfuvirtide showed similar anti-HIV-1 profile in the time of drug addition assay, HIV-2 EHO and HIV-2 ROD infection were affected by PD 404182 derivatives, in contrast with the less effective enfuvirtide [21] , suggesting that PD 404182 derivatives may not be directed at the HIV gp41 envelope protein. Recent reports have suggested that the antiviral activities of compound 1 against HIV, HCV, and pseudotype lentiviruses were derived from disruption of the structural integrities of virions [2] . Although the mechanism of action of PD 404182 derivatives is not fully understood at this In conclusion, the author have designed and synthesized PD 404182 derivatives for a novel series of anti-HIV agents. Comprehensive SAR studies demonstrated that the 6-6-6 fused pyrimido [1,2-c] [1, 3] benzothiazine scaffold and the heteroatom arrangement in the thiazinimine moiety are indispensable for the inhibitory activity of 1 (PD 404182) against HIV infection. Optimization studies of the benzene and cyclic amidine rings indicate that the introduction of a hydrophobic group on the benzene ring is more effective in improving the antiviral activity, giving potential favorable interaction(s) with the target molecule(s). The most potent compound, 32c, had anti-HIV activity three times higher than that of the parent 1. In addition, PD 404182 derivatives could be promising agents for treatment of HIV-2 infection. The author also revealed, using a time of drug addition experiment, that PD 404182 derivatives prevent the HIV infection process at a fusion or binding process. All moisture-sensitive reactions were performed using syringe-septum cap techniques under an Ar atmosphere and all glasswares were dried in an oven at 80°C for 2 h prior to use. Melting points were measured by a hot stage melting point apparatus (uncorrected). For flash chromatography, Wakogel C-300E (Wako) or aluminum oxide 90 standardized (Merck) was employed. For preparative TLC, TLC silica gel 60 F254 (Merck) or TLC aluminum oxide 60 F254 basic (Merck), or NH 2 Silica Gel 60 F254 Plate (Wako) were employed. For analytical HPLC, a COSMOSIL 5C18-ARII column (4.6 9 250 mm, Nacalai Tesque, Inc., Kyoto, Japan) was employed with method A [a linear gradient of CH 3 CN containing 0.1 % (v/v) TFA] or method B [a linear gradient of CH 3 CN containing 0.1 % (v/v) NH 3 ] at a flow rate of 1 mL/min on a Shimadzu LC-10ADvp (Shimadzu Corp., Ltd., Kyoto, Japan), and eluting products were detected by UV at 254 nm. Preparative HPLC was performed using a COSMOSIL 5C18-ARII column (20 9 250 mm, Nacalai Tesque Inc.) with a linear gradient of MeCN containing 0.1 % (v/v) NH 3 at a flow rate of 8 mL/min on Shimadzu LC-6AD (Shimadzu corporation, Ltd). 1 H-NMR spectra were recorded using a JEOL AL-400 or a JEOL ECA-500 spectrometer, and chemical shifts are reported in d (ppm) relative to Me 4 Si (CDCl 3 ) or DMSO (DMSO-d 6 ) as internal standards. 13 C-NMR spectra were recorded using a JEOL AL-400 or JEOL ECA-500 spectrometer and referenced to the residual solvent signal. 19 F-NMR spectra were recorded using a JEOL ECA-500 and referenced to the internal CFCl 3 (d F 0.00 ppm). 1 H-NMR spectra are tabulated as follows: chemical shift, multiplicity (b = broad, s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet), coupling constant(s), and number of protons. Exact mass (HRMS) spectra were recorded on a JMS-HX/HX 110A mass spectrometer. Infrared (IR) spectra were obtained on a JASCO FT/IR-4100 FT-IR spectrometer with JASCO ATR PRO410-S. To a suspension of 3 (33.0 mg, 0.19 mmol) and Et 3 N (0.068 mL, 0.47 mmol) in CH 2 Cl 2 (10.0 mL) was added dropwise a solution of thiophosgene (0.016 mL, 0.21 mmol) in CH 2 Cl 2 (1.0 mL) at 0°C. After being stirred at rt for 1 h, the mixture was quenched with sat. NaHCO 3 . The whole was extracted with EtOAc. The extract was washed with sat. NaHCO 3 , brine, and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over silica gel with n-hexane-EtOAc (3:1) to give the title compound 5 as yellow solid (41.9 mg, [99 %): mp 135-136°C (from CHCl 3 -n-hexane); IR (neat) cm -1 : 1655 (C=N); 1 H-NMR (400 MHz, CDCl 3 ) d: 2.03-2.08 (2H, m, CH 2 ), 3.68 (2H, t, J = 5.5 Hz, CH 2 ), 4.30 (2H, t, J = 6.1 Hz, CH 2 ), 7.21 (1H, d, J = 8.5 Hz, Ar), m, Ar), m, Ar), 8.00 (1H, d, J = 7.8 Hz, Ar) ; 13 C-NMR (100 MHz, CDCl 3 ) d: 21.1, 44.5, 49.2, 115.9, 116.9, 125.4, 125.7, 133.0, 139.7, 150.9, 180.8; Anal. calcd for C 11 H 10 N 2 OS: C, 60.53; H, 4.62; N, 12.83. Found: C, 60.23; H, 4.72; N, 12.62. 3.1.3 Synthesis of 3,4-Dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzoxazin-6-imine ( 20.6, 43.4, 44.1, 115.2, 116.2, 123.9, 125.5, 132.3, 142.5, 150.4, 150.7; Anal. calcd for C 11 H 11 N 3 O: C, 65.66; H, 5.51; N, 20.88. Found: C, 65.55; H, 5.40; N, 20.70. 3.1.4 Synthesis of 3,4-Dihydro-2H,6H-pyrimido [1,2-c] quinazolin-6(7H)-thione (8) Xylene (4.0 mL) was added to a flask containing 3,4-dihydro-2H,6H-pyrimido [1,2-c] 20.6, 44.0, 46.7, 114.8, 117.6, 123.8, 125.1, 132.1, 135.9, 142.1, 174. 3.1.5 Synthesis of 3,4-Dihydro-2H,6H-pyrimido [1,2-c] quinazolin-6-amine (9) 2-[N-(p-Toluenesulfonyl)amino]benzaldehyde (13) . To a solution of 2-aminobenzylalcohol 12 (2.0 g, 16.2 mmol) and pyridine (1.6 mL, 19.4 mmol) in CHCl 3 (60 mL) was added a solution of p-TsCl (3.4 g, 18. 0 mmol) in CHCl 3 (17 mL), and the mixture was stirred at rt for 3 h. After concentration, EtOAc and sat. NH 4 Cl were added to the residue. The organic phase was separated and dried over MgSO 4 . After concentration, the resulting solid was added to a suspension of PCC (5.2 g, 24.3 mmol) and silica gel (10.6 g) in CHCl 3 (70 mL). After being stirred at rt for 2 h, the mixture was filtered and concentrated. The residue was purified by flash chromatography over silica gel with n-hexane-EtOAc (9:1) to give the title compound 13 as colorless solid ( (14). To a solution of 13 (2.75 g, 10 mmol) in t-BuOH (94 mL) was added propylenediamine (969 mg, 11 mmol). The mixture was stirred at 70°C for 30 min, and then K 2 CO 3 (4.15 g, 30 mmol) and I 2 (3.17 g, 12.5 mmol) were added. After being stirred at same temperature for 3 h, the mixture was quenched with sat. Na 2 SO 3 until the iodine color disappeared. The organic layer was separated and concentrated. The resulting solid was dissolved in H 2 O. The whole was extracted with CHCl 3 , and dried over MgSO 4 . After concentration, the resulting solid was recrystallized from CHCl 3 -Et 2 O-n-hexane to give the title compound 14 as pale yellow crystals (3. Compound 9. To a flask containing 14 (164.7 mg, 0.5 mmol) was added conc. H 2 SO 4 (5.0 mL). After being stirred at 100°C for 30 min, the mixture was cooled to 0°C, and then pH was adjusted to 12-14 with 2 N NaOH. The whole was extracted with CHCl 3 , and dried over MgSO 4 . After concentration, the residue was dissolved in anhydrous EtOH (2 mL). Then, BrCN (105.9 mg, 1.0 mmol) was added to the mixture under an Ar atmosphere. After being stirred under reflux for 2 h, the reaction was quenched with 2N NaOH. The whole was extracted with CHCl 3 , and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over aluminum oxide with EtOAc-MeOH (95:5) to give the title compound 9 as colorless solid (66.0 mg, 66 %): mp 259-260°C (from CHCl 3 -n-hexane); IR (neat) cm -1 : 1620 (C=N), 1603 (C=N); 1 H-NMR (400 MHz, DMSO-d 6 ) d: 1.81-1.87 (2H, m, CH 2 ), 3.44 (2H, t, J = 5.4 Hz, CH 2 ), 3.70 (2H, t, J = 6.1 Hz, CH 2 ), 6.49 (2H, br s, NH 2 ), 6.87-6.95 (2H, m, Ar), 7.27-7.31 (1H, m, Ar), 7.87 (1H, dd, J = 7.9, 1.1 Hz, Ar); 13 C-NMR (100 MHz, DMSO-d 6 ) d: 20.0, 42.8, 42.9, 118.9, 120.7, 122.7, 124.3, 131.1, 145.6, 146.6, 151.6 [1, 3] benzothiazin-6-one (11) 3,4-Dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazine-6-thione 10 (58.6 mg, 0.25 mmol) was suspended into a 0.1 M NaOH in MeOH-H 2 O (9:1, 5 mL). After being stirred under reflux for 12 h, the mixture was concentrated. To a stirring solution of the residue and Et 3 N (0.029 mL, 2.0 mmol) in CH 2 Cl 2 (16.6 mL) was added dropwise a solution of triphosgene (155.8 mg, 0.52 mmol) in CH 2 Cl 2 (1.7 mL) at 0°C. After being stirred at rt for 1 h, the mixture was quenched with sat. NaHCO 3 . The whole was extracted with CHCl 3 . The extract was washed with sat. NaHCO 3 , brine, and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over silica gel with n-hexane-EtOAc ( 20.8, 42.4, 45.2, 124.4, 125.8, 126.8, 128.9, 129.2, 130.9, 146.1, 162.8 [1, 3] benzothiazin-6-imine 22k (88.1 mg, 0.25 mmol) and Pd(OAc) 2 (5.6 mg, 0.025 mmol) and KOt-Bu (84.2 mg, 0.75 mmol) in toluene (2.0 mL) were added P(tert-Bu) 3 (0.009 mL, 0.038 mmol) and 2 N Me 2 NH in THF (0.38 mL, 0.75 mmol). After being stirred at reflux for 1 h, the mixture was filtered through a Celite pad and concentrated. The residue was purified by flash chromatography over aluminum oxide with n-hexane-EtOAc ( Compound 25a. TFA (2.0 mL) was added to a mixture of 22a (63.3 mg, 0.2 mmol) in small amount of CHCl 3 and MS4 Å (300 mg, powder, activated by heating with Bunsen burner). After being stirred under reflux for 1 h, the mixture was concentrated. To a stirring mixture of the residue in CHCl 3 was added dropwise Et 3 N at 0°C to adjust pH to 8-9. The whole was extracted with EtOAc. The extract was washed with sat. NaHCO 3 , brine, and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over aluminum oxide with n-hexane-EtOAc (7:3) to give the title compound 25a as colorless solid (38.2 mg, 73 %): mp 150-151°C (from CHCl 3 -n-hexane); IR (neat) cm -1 : 1600 (C=N), 1562 (C=N); 1 H-NMR (500 MHz, CDCl 3 ) d: 1.93-1.98 (2H, m, CH 2 ), 2.98 (6H, s, 2 9 CH 3 ), 3.64 (2H, t, J = 5.7 Hz, CH 2 ), 4.00 (2H, t, J = 6.3 Hz, CH 2 ), 6.17 (1H, d, J = 2.3 Hz, Ar), 6.55 (1H, dd, J = 9.2, 2.3 Hz, Ar), 7.01 (1H, br s, NH), 8.05 (1H, d, J = 9.2 Hz, Ar); 13 C-NMR (125 MHz, CDCl 3 ) d: 21.1, 40.0 (2C), 43.8, 44.7, 104.4, 110.7, 114.4, 129.8, 129.9, 146.7, 151.3, 154 [1, 3] benzothiazin-6imine (28). To a suspension of N-(tert-Butyl)-3,4-dihydro-9-nitro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 22e (477.0 mg, 1.5 mmol) in EtOH (10 mL -2H,6H-pyrimido [1,2-c] (N,N-Dimethylamino)-3,4-dihydro- 2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine (25a) N-(tert-Butyl)-9-(N 0 ,N 0 H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine (22a). To a mixture of N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2- c] To a flask containing 28 (108.5 mg, 0.38 mmol), MeONa (30.6 mg, 0.57 mmol), and paraformaldehyde (34.2 mg, 1.1 mmol) was added unhydrous MeOH (2.5 mL) under an Ar atmosphere, and stirring was continued for 5 h under reflux. Then, NaBH 4 (28.8 mg, 0.76 mmol) was added to the mixture and stirring was continued for additional 30 min under reflux. After concentration, the residue was dissolved in EtOAc, and washed with sat. NaHCO 3 , brine, and dried over MgSO 4 . After concentration, the residue was purified by flash column chromatography over aluminum oxide with n-hexane-EtOAc (1:1) to give the title compound 22b as yellow solid (104.9 mg, 91 %): mp 156-158°C (from CHCl 3 -n-hexane); IR (neat) cm 2, 44.7, 45.5, 54.0, 104.9, 111.8, 116.3, 129.7, 130.4, 139.0, 148.3, 150.6; HRMS (FAB) : m/z calcd for C 16 Compound 25b. Using the general procedure as described for 25a, compound 22b (30.7 mg, 0.1 mmol) was allowed to react for 1 h with TFA (1.0 mL) and MS4Å (200 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:1 to 0:1) gave the title compound 25b as pale yellow solid (9.0 mg, 37 %): mp 129-131°C (from CHCl 3 -n-hexane); IR (neat) cm 21.1, 30.2, 43.9, 44.6, 104.0, 111.9, 129.2, 130.1, 130.3, 146.9, 150.8, 154.1; Anal. calcd for C 12 H 14 N 4 S: C, 58.51; H, 5.73; N, 22.74. Found: C, 58.30; H, 5.62; N, 22.45. 3.1.9 Synthesis of 9-(N-Acetylamino)-3,4-dihydro-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (25c) 9-(N-Acetylamino)-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (22c). To a mixture of 9-amino-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 28 (100.9 mg, 0.35 mmol), Et 3 N (0.015 mL, 1.05 mmol), DMAP (4.3 mg, 0.04 mmol) in CH 2 Cl 2 (3.5 mL) was added Ac 2 O (0.066 mL, 0.70 mmol) under an Ar atmosphere. After being stirred under reflux for 1 h, sat. NaHCO 3 was added to the mixture. The whole was extracted with EtOAc. The extract was washed with brine, and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:1 to 0:1) to give the title compound 22c as colorless solid ( Compound 25c. Using the general procedure as described for 28a, compound 25c (120.1 mg, 0.36 mmol) was allowed to react for 10 h. Purification by recrystallization from MeOH-CHCl 3 -Et 2 O gave the title compound 25c as pale yellow crystals (64.9 mg, 65 %): mp 214°C (decomp.); IR (neat) cm 20.3, 24.1, 43.3, 43.6, 112.2, 116.7, 119.3, 129.2, 129.9, 141.7, 146.3, 149.5, 169.0 To a mixture of N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2- 20.9, 26.7, 43.8, 45.1, 123.6, 125.7, 129.3, 129.6, 130.4, 138.3, 146.0, 152.6, 196.7 9. 0 mmol) and NaH (716.8 mg, 17.9 mmol; 60 % oil suspension) in DMF (29.8 mL) was added tert-butylisothiocyanate (2.28 mL, 17.9 mmol) under an Ar atmosphere, and the mixture was stirred at -20°C to rt for 2 days. The whole was extracted with EtOAc, and the extract was washed with sat. NaHCO 3 , brine, and dried over Na 2 SO 4 . After concentration, the residue was purified by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) to give the title compound 22e as pale yellow solid ( Compound 25e. Using the general procedure as described for 25a, compound 22e (47.8 mg, 0.15 mmol) was allowed to react for 1 h with TFA (1.5 mL) and MS4Å (225 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (19:1 to 1:1) gave the title compound 25e as pale yellow solid (24.9 mg, 63 %): mp 170-172°C (from CHCl 3 -n-hexane); IR (neat) cm 20.8, 43.8, 45.2, 118.9, 120.5, 130.4, 130.8, 131.7, 145.1, 148.7, 151.3; Anal. calcd for C 11 H 10 N 4 O 2 S: C, 50.37; H, 3.84; N, 21.36. Found: C, 50.29; H, 4.03; N, 21.08. 3.1.12 Synthesis of 3,4-Dihydro-9-methoxy-2H,6Hpyrimido [1,2-c] [1, 3] benzothiazin-6-imine (25f) 3,4-Dihydro-9-methoxy-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazine-6-thione 21f (66.1 mg, 0.25 mmol) was suspended into a 0.1 M NaOH in MeOH-H 2 O (9:1) (5 mL), and the mixture was stirred for 12 h under reflux. After concentration, the residue was suspended in anhydrous EtOH (1 mL). BrCN (53.0 mg, 0.50 mmol) was added under an Ar atmosphere, and the mixture was stirred for 2 h under reflux. The reaction was quenched with 2 N NaOH, and the whole was extracted with CHCl 3 , and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1) 3.1.13 Synthesis of 3,4-Dihydro-9-methyl-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (25g) 3,4-Dihydro-9-methyl-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazine-6-thione 21g (62.1 mg, 0.25 mmol) was subjected to the general procedure as described for 25f to give the title compound 25g as colorless solid (39.2 mg, 68 %): mp 121°C (from CHCl 3 -n-hexane); IR (neat) cm -1 : 1620 (C=N), 1569 (C=N); 1 H-NMR (500 MHz, CDCl 3 ) d: 1.94-1.99 (2H, m, CH 2 ), 2.32 (3H, s, CH 3 ), 3.67 (2H, t, J = 5.7 Hz, CH 2 ), 4.01 (2H, t, J = 6.3 Hz, CH 2 ), 6.84 (1H, s, Ar), 7.02 (1H, d, J = 8.6 Hz, Ar), 7.16 (1H, br s, NH), 8.10 (1H, d, J = 8.6 Hz, Ar); 13 C-NMR (125 MHz, CDCl 3 ) d: 21.1, 21.1, 43.8, 44.9, 123.6, 124.1, 127.4, 128.6, 128.8, 141.1, 146.6, 153.6 3.1.14 Synthesis of 9-(n-Butyl)-3,4-dihydro-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (25h) 9-(n-Butyl)-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (22h). To a mixture of N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2- Compound 25h. Using the general procedure as described for 25a, compound 22h (10.3 mg, 0.03 mmol) was allowed to react for 1 h with TFA (1.0 mL) and MS4 Å (150 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1) gave the title compound 25h as colorless solid (5.2 13.8, 21.1, 22.2, 33.0, 35.2, 43.8, 44.9, 123.0, 124.4, 126.8, 128.6, 128.8, 146.1, 146.6, 153.7 [1, 3] benzothiazine-6-thione 21i (63.1 mg, 0.25 mmol) was subjected to the general procedure as described for 25f to give the title compound 15; H, 4.28; N, 17.86. Found: C, 56.13; H, 4.44; N, 17.78. 3.1.16 Synthesis of 3,4-Dihydro-9-trifluoromethyl-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (25j) 2-(2-Fluoro-4-trifluoromethylphenyl) -1,4,5,6-tetrahydropyrimidine (18j) . To a solution of 2-fluoro-4-trifluoromethylbenzaldehyde 15j (1.00 g, 5.21 mmol) in t-BuOH (49 mL) was added propylenediamine (424.7 mg, 5.73 mmol). The mixture was stirred at 70°C for 30 min, and then K 2 CO 3 (2.16 g, 15.6 mmol) and I 2 (1.65 g, 6.51 mmol) were added. After being stirred at same temperature for 3 h, the mixture was quenched with sat. Na 2 SO 3 . The organic layer was separated and concentrated. The resulting solid was dissolved with H 2 O, and then pH was adjusted to 12-14 with 2 N NaOH. The whole was extracted with CHCl 3 , and the extract was dried over MgSO 4 . After concentration, the resulting solid was recrystallized from CHCl 3 -n-hexane to give the title compound 18j as colorless crystals (0. , 4.06; N, 11.43 . 6-imine (22j) . Using the general procedure as described for 22e, compound 18j (246.2 mg, 1.0 mmol) was allowed to react at 80°C for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc Compound 25j. Using the general procedure as described for 25a, compound 22j (68.3 mg, 0.20 mmol) was allowed to react for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 45.4, 54.3, 124.4, 126.7, 126.8, 129.1, 130.1, 130.9, 137.2, 147.2; Anal. calcd for C 15 H 18 BrN 3 S: C, 51.14; H, 5.15; N, 11.93. Found: C, 51.30; H, 5.07; N, 11.82. Compound 25k. Using the general procedure as described for 25a, compound 22k (52.8 mg, 0.15 mmol) was allowed to react for 2 h with TFA (1.5 mL) and MS4Å (225 mg). Purification by flash chromatography over silica gel with n-hexane-EtOAc (2:1) 20.9, 43.8, 44.9, 125.0, 125.6, 125.9, 129.5, 130.4, 130.7, 145.8, 152.4; Anal. calcd for C 11 H 10 BrN 3 S: C, 44.61; H, 3.40; N, 14.19. Found: C, 44.37; H, 3.28; N, 13.93. 3.1.18 Synthesis of 3,4-Dihydro-9-phenyl-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (25l) N-(tert-Butyl)-3,4-dihydro-9-phenyl-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (22l). To a solution of N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6Hpyrimido [1,2-c] [1, 3] benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) and phenylboronic acid (21.9 mg, 0.18 mmol) in a mixture of toluene (1.5 mL), EtOH (0.9 mL) and 1 M aq. K 2 CO 3 (1.5 mL) was added Pd(PPh 3 ) 4 (6.9 mg, 4 mol %) and PdCl 2 (dppf)ÁCH 2 Cl 2 (3.7 mg, 3 mol %). After being stirred at reflux for 1 h, the mixture was extracted with CHCl 3 . The extract was dried over MgSO 4 and concentrated. The residue was purified by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) to give the title compound 22l as colorless solid ( 21.1, 43.8, 45.0, 121.8, 121.8, 125.1, 125.5, 127.0 (2C), 128.2, 128.9 (2C), 129.4, 139.2, 143.5, 146.5, 153.4 Compound 25m. Using the general procedure as described for 25a, compound 22m (60.4 mg, 0.2 mmol) was allowed to react for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (8:2) 43.8, 44.9, 116.4, 121.1, 124.0, 125.8, 129.0 (2C), 135.2, 139.8, 146.4, 153.3 3.1.20 Synthesis of 3,4-Dihydro-9-styryl-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (25n) N-(tert-Butyl)-3,4-dihydro-9-styryl-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (22n). Using the general procedure as described for 22l, N-(tert-butyl)-9bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with styrylboronic acid pinacol ester (41.4 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 22n as colorless solid (50.9 mg, 90 %): mp 124.5-125°C (from CHCl 3 -n-hexane); IR (neat) cm 1, 45.4, 54.2, 122.2, 124.0, 126.6, 126.7 (2C), 127.0, 128.1, 128.7 (2C), 128.8, 129.4, 130.7, 136.8, 138.3, 139.2, 147.7 Compound 25n. Using the general procedure as described for 25a, compound 22n (31.7 mg, 0.084 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 43.8, 45.0, 121.2, 124.2, 125.5, 126.6, 126.7 (2C), 128.2, 128.7 (2C), 129.1, 129.2, 131.1, 136.6, 139.7, 146.4, 153.3; Anal. calcd for C 19 H 17 N 3 S: C, 71.44; H, 5.36; N, 13.15. Found: C, 71.17; H, 5.24; N, 13.07. 3.1.21 Synthesis of 3,4-Dihydro-9-pentenyl-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (25o) N-(tert-Butyl)-3,4-dihydro-9-pentenyl-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (22o). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with pentenylboronic acid pinacol ester 1, 45.1, 45.4, 54.1, 121.6, 123.6, 126.0, 128.5, 128.6, 129.1, 133.4, 138.5, 139.8, 147.8 Compound 25o. Using the general procedure as described for 25a, compound 22o (40.0 mg, 0.12 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (8:2) 13.7, 21.0, 22.3, 35.1, 43.8, 44.9, 120.6, 123.8, 124.9, 128.3, 128.9, 129.0, 133.9, 140.3, 146.5, 153.5 -9-nitro-2H, 6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine (25e) N-(tert-Butyl)-3,4-dihydro-9-nitro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6- imine (22e). To a mixture of 2-(2-fluoro-4-nitrophenyl)-1,4,5,6-tetrahydropyrim- idine 18e (2.0 g, -3,4-dihydro-2H, 6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine (25i) 9-Fluoro-3,4-dihydro-2H,6H-pyrimido[1,2-c]N-(tert-Butyl)-3,4-dihydro-9-trifluoromethyl-2H, 6H-pyrimido[1,2-c][1,3] benzothiazin- 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (25p) 9-Azido-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin- 6imine (22p) . To a solution of 9-amino-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 28 (100.9 mg, 0.35 mmol) in AcOH (2 mL) and H 2 O (1 mL) was added NaNO 2 (33.8 mg, 0.49 mmol) at 0°C, and the stirring was continued for 1 h. NaN 3 (34.1 mg, 0.53 mmol) was added to the reaction mixture, and stirring was continued for 30 min at rt. Reaction mixture was neutralized with K 2 CO 3 , and the whole was extracted with CHCl 3 , and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over aluminum oxide with n-hexane-EtOAc ( 43.1, 44.2, 113.7, 117.0, 122.6, 130.2, 130.8, 141.9, 144.7, 150 9-(4-Benzoylphenyl)-N-(tert-butyl)-3,4-dihydro-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (22q). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2- Compound 25q. Using the general procedure as described for 25a, compound 22q (30.4 mg, 0.067 mmol) was allowed to react for 1 h with TFA (1.0 mL) and MS4 Å (150 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 3]benzothiazin-6-imine (23a). To a mixture of 10-bromo-N-(tert-butyl)-3,4dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 23k (600.2 mg, 1.70 mmol) and Pd(Pt-Bu 3 ) 2 (174.2 mg, 0.341 mmol) and KOt-Bu (573.3 mg, 5.11 mmol) in toluene (1.7 mL) was added 2.0 M Me 2 NH in THF (2.55 mL, 5.11 mmol). The reaction was heated using a microwave reactor (standard mode) for 10 min at 170°C. The whole was extracted with EtOAc. The extract was washed with brine, and dried over Na 2 SO 4 . After concentration, the residue was purified by flash chromatography over silica gel with n-hexane-EtOAc 1, 45.5, 54.0, 111.6, 115.4, 115.8, 125.3, 128.7, 139.7, 148.8, 149.3 Compound 26a. TFA (0.63 mL) was added to a mixture of 23a (20 mg, 0.063 mmol) and MS4Å (110 mg, powder, activated by heating with Bunsen burner) in small amount of CHCl 3 . After being stirred under reflux for 40 min, the mixture was added dropwise to Et 3 N at 0°C to adjust pH to [8] [9] . The whole was extracted with EtOAc. The extract was washed with sat. NaHCO 3 , brine, and dried over Na 2 SO 4 . After concentration, the residue was purified by preparative TLC over aluminum oxide with n-hexane-EtOAc (7:3) to give the title compound 26a as yellow solid (11.4 mg, 68 1, 44.3, 111.8, 114.6, 116.3, 124.6, 126.3, 148.7, 149.4, 154.4 Compound 26e. TFA (3.2 mL) was added to compound 23e (100 mg, 0.314 mmol). After being stirred under reflux for 1.5 h, the mixture was added dropwise to Et 3 N at 0°C to adjust pH to 8-9. The whole was extracted with EtOAc. The extract was washed with sat. NaHCO 3 , brine, and dried over Na 2 SO 4 . After concentration, the residue was purified by preparative TLC over aluminum oxide with n-hexane-EtOAc (7:3) to give the title compound 26e as orange solid (15.9 mg, 19. Compound 26f. TFA (0.88 mL) was added to compound 23f (26.7 mg, 0.088 mmol). After being stirred under reflux for 3 h, the mixture was added dropwise to Et 3 N at 0°C to adjust pH to 8-9. The whole was extracted with EtOAc. The extract was washed with sat. NaHCO 3 , brine, and dried over Na 2 SO 4 . After concentration, the residue was purified by preparative TLC over aluminum oxide with n-hexane-EtOAc (7:3) to give the title compound 26f as colorless solid 43.9, 44.9, 55.6, 111.9, 119.3, 119.9, 124.8, 127.9, 146.7, 153.9, 158.3; Anal. calcd for C 12 H 13 N 3 OS: C, 58.28; H, 5.30; N, 16.99. Found: C, 58.24; H, 5.36; N, 16.46 . The purity of the compound was 92 % by HPLC. 2-(2-Fluoro-5-methylphenyl)-1,4,5,6-tetrahydropyrimidine (19g). 2-Fluoro-5methylbenzaldehyde 16g (3.0 g, 21.7 mmol) was subjected to the general procedure as described for 18j to give the title 19g as colorless crystals ( [1, 3] benzothiazin-6-imine (23g). To a mixture of compound 19g (0.50 g, 2.6 mmol) and KOt-Bu (0.58 g, 5.2 mmol) in DMAc (8.7 mL) was added tert-butylisothiocyanate (0.66 mL, 5.2 mmol) under an Ar atmosphere. After being stirred at 80°C for 3 h, the whole was extracted with EtOAc. The whole was washed with sat. NaHCO 3 , brine, and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over silica gel with n-hexane-EtOAc (1:1) to give the title compound 23g as colorless solid (0.21 g, 28 %): mp 76-77°C (from n-hexane); IR (neat) cm 1, 45.4, 54.1, 124.4, 125.7, 127.6, 128.6, 131.1, 135.9, 138.7, 148.2; HRMS (FAB) : m/z calcd for C 16 Compound 26g. Using the general procedure as described for 25a, compound 23g (200 mg, 0.7 mmol) was allowed to react for 1 h with TFA (3.0 mL) and MS4Å (450 mg). Purification by preparative TLC over aluminum oxide with nhexane-EtOAc (9:1) gave the title compound 26g as colorless solid (150 mg 21.1, 43.8, 44.9, 123.5, 125.4, 126.5, 129.0, 131.6, 136.3, 146.9, 153.7; HRMS (FAB) : m/z calcd for C 12 H 14 N 3 S [M ? H] + 232.0908; found: 232.0913. 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (26k) 2-(5-Bromo-2-fluorophenyl) -1,4,5,6-tetrahydropyrimidine (19k [1, 3] benzothiazin-6-imine (23k). Using the general procedure as described for 22e, compound 19k (257.1 mg, 1.00 mmol) was allowed to react at rt overnight. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 1, 45.4, 54.2, 119.7, 125.9, 128.1, 129.3, 131.2, 133.0, 137.4, 146.7; Anal. calcd for C 15 H 18 BrN 3 S: C, 51.14; H, 5.15; N, 11.93. Found: C, 51.09; H, 4.98; N, 11.89. Compound 26k. Using the general procedure as described for 25a, compound 23k (52.8 mg, 0.15 mmol) was allowed to react for 2 h with TFA (1.5 mL) and MS4Å (225 mg). Purification by flash chromatography over silica gel with n-hexane-EtOAc (2:1) gave the title compound 26k as colorless crystals (39.7 mg, 89 %): mp 106-107°C (from CHCl 3 -n-hexane); IR (neat) cm 20.9, 43.8, 44.9, 120.0, 125.0, 127.8, 128.3, 131.6, 133.5, 145.4, 152.5; Anal. calcd for C 11 H 10 BrN 3 S: C, 44.61; H, 3.40; N, 14.19. Found: C, 44.51; H, 3.66; N, 14. 06. 6H-pyrimido [1,2-c] [1, 3] benzothiazin- 6-imine (26l) N-(tert-Butyl)-3,4-dihydro-10-phenyl-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (23l). Using the general procedure as described for 22l, 10-bromo-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 23k (52.8 mg, 0.15 mmol) was allowed to react for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 23l as colorless solid (32.6 mg, 62 1, 45.5, 54.2, 125.0, 126.9, 127.0 (2C), 127.4, 127.9, 128.1, 128.7 (2C), 128.7, 138.2, 139.1, 140.0, 147.9; HRMS (FAB) Compound 26l. Using the general procedure as described for 25a, compound 23l (13.1 mg, 0.037 mmol) was allowed to react for 2 h with TFA (1.0 mL) and MS4Å (150 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1) gave the title compound 26l as colorless solid (8.4 21.1, 43.9, 45.0, 124.0, 126.9, 127.1 (2C), 127.3, 127.6, 128.8 (2C), 129.2, 139.4, 139.8, 146.6, 152.1, 153.3; Anal. calcd for C 17 H 15 N 3 S: C, 69.59; H, 5.15; N, 14.32. Found: C, 69.61; H, 5.13; N, 14.22. 3.1.30 Synthesis of 3,4-Dihydro-10-vinyl-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (26m) N-(tert-Butyl)-3,4-dihydro-10-vinyl-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (23m). Using the general procedure as described for 22l, 10-bromo-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 23k (52.8 mg, 0.15 mmol) was allowed to react with vinylboronic acid pinacol ester (0.031 mL, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 23m as a colorless oil (30.5 mg, 68 %): IR (neat) cm 1, 45.4, 54.1, 114.1, 124.7, 126.6, 127.4, 127.8, 128.2, 135.7, 135.9, 138.2, 147.9; HRMS (FAB) : m/z calcd for C 17 Compound 26m. Using the general procedure as described for 25a, compound 23m (7.3 mg, 0.024 mmol) was allowed to react for 1 h with TFA (1.0 mL) and MS4Å (150 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1) gave the title compound 26m as colorless solid (3.7 43.8, 44.9, 114.5, 123.8, 126.8, 126.9, 127.8, 127.9, 135.6, 135.9, 146.5, 153 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (26q) 10-(4-Benzoylphenyl)-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (23q). Using the general procedure as described for 22l, 10-bromo-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2- 5, 136.9, 137.6, 137.9, 141.6, 143.3, 147.5, 196 454.1953; found: 454.1952 . Compound 26q. Using the general procedure as described for 25a, compound 23q (36.2 mg, 0.08 mmol) was allowed to react for 1 h with TFA (1.0 mL) and MS4Å (150 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 6 Hz, CH 2 ), 4.05 (2H, t, J = 6.2 Hz, CH 2 ), 7.15 (1H, d, J = 8.0 Hz, Ar), m, Ar), m, Ar), 7.73 (2H, d, J = 8.5 Hz, Ar), 7.82 (2H, dd, J = 8.2, 1.3 Hz, Ar), 7.88 (2H, d, J = 8.5 Hz, Ar), 8.57 (1H, d, J = 2.0 Hz, Ar) ; 13 C-NMR (100 MHz, CDCl 3 ) d: 21.0, 43.9, 45.0, 124.3, 126.7 (2C), 127.2, 127.6, 128.3 (2C), 128.8, 129.2, 130.0 (2C), 130.7 (2C), 132.4, 136.5, 137.7, 138.0, 143.7, 146.3, 152.9, 196.1; HRMS (FAB) 5.14; N, 14.28. Found: C, 61.23; H, 5.13; N, 14.26 . N-(tert-Butyl)-11-fluoro-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (24i). Using the general procedure as described for 22e, compound 20i (196.2 mg, 1.0 mmol) was allowed to react at rt overnight. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 24i as colorless solid (212.6 mg, 73 %): mp 81°C (from n-hexane); IR (neat) cm -1 : 1592 (C=N); 1 H-NMR (500 MHz, CDCl 3 ) d: 1.37 (9H, s, 3 9 CH 3 ), 1.90-1.95 (2H, m, CH 2 ), 3.66 (2H, t, J = 5.7 Hz, CH 2 ), 3.80 (2H, t, J = 6.6 Hz, CH 2 ), m, Ar), m, Ar) ; 13 Compound 27i. Using the general procedure as described for 25a, compound 24i (58.3 mg, 0.20 mmol) was allowed to react for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1) gave the title compound 15; H, 4.28; N, 17.86. Found: C, 56.05; H, 4.28; N, 17.71. 3.1.33 Synthesis of 8-Bromo-3,4-dihydro-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (27k) [1, 3] benzothiazin-6-imine (24k). Using the general procedure as described for 22e, compound 20k (257.1 mg, 1.00 mmol) was allowed to react at rt overnight. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 3, 45.3, 54.3, 118.6, 126.5, 127.5, 129.9, 130.7, 133.8, 137.4, 147.5; Anal. calcd for C 15 H 18 BrN 3 S: C, 51.14; H, 5.15; N, 11.93. Found: C, 50.89; H, 5.06; N, 11.83. Compound 27k. Using the general procedure as described for 25a, compound 24k (52.8 mg, 0.15 mmol) was allowed to react for 2 h with TFA (1.5 mL) and MS4Å (225 mg). Purification by flash chromatography over silica gel with nhexane-EtOAc (2:1) gave the title compound 27k as colorless solid ( 20.8, 43.7, 45.0, 117.6, 126.8, 127.9, 128.8, 130.5, 134.1, 146.2, 152.7; Anal. calcd for C 11 H 10 BrN 3 S: C, 44.61; H, 3.40; N, 14.19. Found: C, 44.36; H, 3.64; N, 13.96. 3.1.34 Synthesis of 3,4-Dihydro-2H,6H-pyrimido [1,2-c] naphtho [2,3-e] [1, 3] thiazin-6-imine (27r) 2-(3-Fluoronaphthalen-2-yl)-1,4,5,6-tetrahydropyrimidine (20r). 1-Fluoro-2naphthaldehyde 17r (0.96 g, 5.52 mmol) was subjected to the general procedure as described for 18j to give the title compound 20r as pale yellow crystals ( N-(tert-Butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] naphtho [2,3-e] [1, 3] thiazin-6-imine (24r). Using the general procedure as described for 22e, compound 20r (228.3 mg, 1.00 mmol) was allowed to react at rt overnight. Purification by flash chromatography over silica gel with n-hexane-EtOAc 3, 45.5, 54.3, 122.5, 125.8, 125.9, 126.3, 126.5, 127.8, 128.5, 129.2, 131.7, 133.9, 138.4, 148.5; HRMS (FAB) Compound 27r. Using the general procedure as described for 25a, compound 24r (64.7 mg, 0.2 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (4:1) gave the title compound 27r as colorless solid (36.6 mg, 68 %): mp 180-181°C (from CHCl 3n-hexane); IR (neat) cm 21.1, 43.9, 45.1, 121.6, 125.0, 125.4, 126.1, 126.3, 128.1, 129.2, 129.2, 131.6, 133.9, 147.1, 153.4; HRMS (FAB) [1,2-c] pyrido [3,2-e] [1, 3] thiazin-6-imine (27s) Using general procedure as described for 25f, reaction of 2-(2-bromopyridin-3-yl)-1,4,5,6-tetrahydropyrimidine 21s (58.8 mg, 0.25 mmol) and purification by flash chromatography over aluminum oxide with n-hexane-EtOAc ( 20.8, 43.8, 45.2, 121.4, 123.7, 136.3, 145.3, 151.2, 151.3, 153.5 20.9, 43.7, 45.1, 123.2, 124.0, 125.1, 125.9, 126.7, 126.7, 127.5, 127.8, 128.5, 133.9, 147.1, 152.7 3,4-Dihydro-2H,6H-pyrimido [1,2-c] thieno [2,3-e] [1, 3] thiazin-6-thione (21u). To a mixture of 20u (122.6 mg, 0.50 mmol) and NaH (40.0 mg, 1.0 mmol; 60 % oil suspension) in DMF (1.7 mL) was added CS 2 (0.060 mL, 1.0 mmol) under an Ar atmosphere. After being stirred at 80°C for 12 h, the mixture was concentrated. The residue was purified by flash chromatography over silica gel with nhexane-EtOAc (8:2) to give the title compound 21u as pale yellow solid (80.5 mg, 67 %): mp 167°C (from CHCl 3 -n-hexane); IR (neat) cm -1 : 1624 (C=N); 13 C-NMR (400 MHz, CDCl 3 ) d: 2.04-2.10 (2H, m, CH 2 ), 3.68 (2H, t, J = 5.5 Hz, CH 2 ), 4.42 (2H, t, J = 6.1 Hz, CH 2 ), 6.76 (1H, d, J = 5.4 Hz, Ar), 7.49 (1H, d, J = 5.4 Hz, Ar); 13 C-NMR (100 MHz, CDCl 3 ) d: 21.5, 45.0, 48.5, 122.3, 128.4, 130.8, 131.0, 141.7, 189.7; HRMS (FAB) : m/z calcd for C 9 H 9 N 2 S 3 [M ? H] + 240.9928; found: 240.9936. Compound 27u. Compound 21u (60.1 mg, 0.25 mmol) was subjected to general procedure as described for 25f to give the title compound 27u as colorless solid (19.4 21.2, 43.5, 44.5, 123.3, 125.9, 127.0, 129.9, 143.7, 153.7; Anal. calcd for C 9 H 9 N 3 S 2 : C, 48.40; H, 4.06; N, 18.82. Found: C, 48.38; H, 3.98; N, 18.75. 3.1.38 Synthesis of 3,4-Dihydro-9-(4methoxycarbonylphenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31a) N-(tert-Butyl)-3,4-dihydro-9-(4-methoxycarbonylphenyl)-2H,6H-pyrimido [1, 2-c] [1, 3] benzothiazin-6-imine (29a). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 4-(methoxycarbonyl)phenylboronic acid ( 2, 45.4, 52.1, 54.2, 123.0, 124.8, 127.0 (2C), 127.3, 129.1, 129.6, 129.8, 130.2 (2C), 138.0, 141.7, 143.8, 147.5, 166.8 Compound 31a. Using the general procedure as described for 25a, compound 29a (38.4 mg, 0.094 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1 to 1:1) gave the title compound 31a as ( 43.8, 45.0, 52.2, 122.0, 125.1, 126.2, 126.9 (2C), 129.5, 129.6, 129.7, 130.2 (2C), 142.1, 143.4, 146.2, 153.0, 166.7; HRMS (FAB) : m/z calcd for C 19 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31b) N-(tert-Butyl)-9-(4-cyanophenyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29b). Using the general procedure as described for 22l, N -(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6imine 22k ( 2, 45.4, 54.2, 111.7, 118.6, 123.0, 124.7, 127.6 (2C), 127.8, 129.3, 130.1, 132.6 (2C), 137.6, 140.7, 143.9, 147.4; HRMS (FAB) Compound 31b. Using the general procedure as described for 25a, compound 29b (32.5 mg, 0.087 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (6:4) gave the title compound 31b as colorless solid (20.8 mg, 75 1 Hz, 2H, CH 2 ), 7.24 (d, J = 1.7 Hz, 1H, Ar), 7.43 (dd, J = 8.3, 1.7 Hz, 1H, Ar), 7.67 (d, J = 8.3 Hz, 2H, Ar), 7.73 (d, J = 8.3 Hz, 2H, Ar), 8.32 (d, J = 8.3 Hz, 1H , Ar); 13 C-NMR (100 MHz, CDCl 3 ) d: 21.0, 43.8, 45.0, 111.9, 118.5, 122.0, 125.0, 126.7, 127.6 (2C), 129.7, 129.9, 132.7 (2C), 141.2, 143.5, 146.0, 152.8; HRMS (FAB) : m/z calcd for C 18 6H-pyrimido [1,2-c] [1, 3] benzothiazin- 6-imine (31c) N-(tert-Butyl)-3,4-dihydro-9-(4-nitrophenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzo thiazin-6-imine (29c). Using the general procedure as described for 22l, N-(tertbutyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] 2, 45.5, 54.3, 123.2, 124.1 (2C), 124.8, 127.8 (2C), 128.0, 129.3, 130.2, 137.5, 140.4, 145.8, 147.4, 147.5 Compound 31c. Using the general procedure as described for 25a, compound 29c (77.0 mg, 0.075 mmol) was allowed to react for 4 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc ( 43.8, 45.0, 122.2, 124.2 (2C), 125.1, 126.9, 127.8 (2C), 129.7, 130.0, 140.8, 145.4, 146.0, 147.6, 152.7; HRMS (FAB) 2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31d) N-(tert-Butyl)-3,4-dihydro-9-(4-trifluoromethylphenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29d). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] 21.8, 29.9 (3C), 45.1, 45.4, 54.2, 122.9, 124.1 (q, J = 271.1 Hz), 124.8, 125.8 (q, J = 3.6 Hz, 2C), 127.3 (2C), 127.4, 129.2, 129.9, 130.0 (q, J = 32.8 Hz), 137.8, 141.3, 142.9, 147.5; 19 F-NMR ( 20.9, 43.8, 44.9, 121.9, 124.0 (q, J = 272.2 Hz, 125.0, 125.7 (t, J = 3.6 Hz, 2C), 126.2, 127.2 (2C), 129.5, 129.6, 130.1 (q, J = 32.4 Hz), 141.7, 142.5, 146.1, 152.8; 19 F-NMR (500 MHz, CDCl 3 ) d: -63.1; Anal. calcd for C 18 H 14 F 3 N 3 S: C, 59.82; H, 3.90; N, 11.63. Found: C, 59.56; H, 3.81; N, 11.48. 3.1.42 Synthesis of 9-(4-Aminocarbonylphenyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6imine (31e) phenyl]-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2c] [1, 3] benzothiazin-6-imine (29e). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] 21.6, 29.7 (3C), 44.7, 45.4, 54.2, 122.9, 124.8, 126.8, 126.9 (2C) , 128.0 (2C), 128. 8, 129.8, 132.6, 137.8, 141.8, 142.6, 148.7, 169.7 (3. 0 mL) and MeOH (10 drops). After being stirred under reflux for 9 h, the mixture was concentrated. To a stirring mixture of this residue in CHCl 3 was added dropwise Et 3 N at 0°C to adjust pH to [8] [9] . The whole was extracted with EtOAc. The extract was washed with sat. NaHCO 3 , brine, and dried over MgSO 4 . After concentration, the residue was purified by preparative TLC over aluminum oxide with to give compound 31e as colorless solid (13.0 mg, 56 %) : mp 222-223°C (from MeOH-CHCl 3 -n-hexane); IR (neat) cm -1 : 1666 (C=O), 1616 (C=N), 1556 (C=N); 1 H-NMR (400 MHz, DMSO-d 6 ) d: 1.83-1.89 (m, 2H, CH 2 ), 3.59 (t, J = 5.1 Hz, 2H, CH 2 ), 3.92 (t, J = 5.7 Hz, 2H, CH 2 ), 7.40 (s, 1H, NH), 2H, Ar), 7.81 (d, J = 8.3 Hz, 2H, Ar), 7.96 (d, J = 8.3 Hz, 2H, Ar), 8.04 (s, 1H, NH), 8.24 (d, J = 8.3 Hz, 1H, Ar), 8.74 (s, 1H, NH) ; 43.1, 44.4, 121.8, 124.3, 125.4, 126.5 (2C), 128.1 (2C), 129.0, 129.7, 133.8, 140.6, 141.1, 145.1, 149.5, 167.3; HRMS (FAB) 2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31f) N-(tert-Butyl)-3,4-dihydro-9-(4-methoxyphenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29f). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6imine 22k ( 1, 45.4, 54.1, 55.3, 114.3 (2C), 122.1, 124.4, 125.9, 128.1 (2C), 128.9, 129.4, 131.9, 138.4, 142.5, 147.8, 159.8; HRMS (FAB) Compound 31f. Using the general procedure as described for 25a, compound 29f (28.4 mg, 0.075 mmol) was allowed to react for 2 h with TFA (1.0 mL) and MS4Å (150 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (3:1) gave the title compound 31f as colorless solid (20.0 mg, 82 %): mp 93-94°C (from CHCl 3 -n-hexane); IR (neat) cm -1 : 1620 (C=N), 1567 (C=N); 1 H-NMR (400 MHz, CDCl 3 ) d: 1.96-2.02 (m, 2H, CH 2 ), 3.71 (t, J = 5.5 Hz, 2H, CH 2 ), 3.85 (s, 3H, CH 3 ), 4.04 (t, J = 6.2 Hz, 2H, CH 2 ), 6.97 (d, J = 8.5 Hz, 2H, Ar), 7.20 (d, J = 1.7 Hz, 1H, Ar), 7.41 (dd, J = 8.3, 1.7 Hz, 1H, Ar), 7.52 (d, J = 8.5 Hz, 2H, Ar), 8.25 (d, J = 8.3 Hz, 1H , Ar); 13 C-NMR (100 MHz, CDCl 3 ) d: 21.0, 43.8, 44.9, 55.4, 114.4 (2C), 121.1, 124.7, 124.8, 128.1 (2C), 129.3, 129.3, 131.5, 143.1, 146.5, 153.5, 159.9; Anal. calcd for C 18 H 17 N 3 OS: C, 66.85; H, 5.30; N, 12.99. Found: C, 66.95; H, 5.50; N, 12.89. 3.1.44 Synthesis of 3,4-Dihydro-9-(4-methylthiophenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin- 6-imine (31g) N-(tert-Butyl)-3,4-dihydro-9-(4-methylthiophenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29g). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] 15.7, 21.9, 30.0 (3C), 45.1, 45.4, 54.2, 122.3, 124.4, 126.4, 126.8 (2C), 127.3 (2C), 129.0, 129.6, 136.0, 138.2, 138.8, 142.2, 147.7 Compound 31g. Using the general procedure as described for 25a, compound 29g (38.5 mg, 0.097 mmol) was allowed to react for 4 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1 to 7:3) gave the title compound 31g as colorless solid (18.4 mg, 56 15.6, 21.0, 43.8, 44.9, 121.3, 124.7, 125.3, 126.7 (2C) 2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31h) N-(tert-Butyl)-3,4-dihydro-9-(4-trifluoromethoxyphenyl)-2H,6H-pyrimido [1, 2-c] [1, 3] benzothiazin-6-imine (29h). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] Compound 31h. Using the general procedure as described for 25a, compound 29h (44.8 mg, 0.103 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1-7:3) gave the title compound 31h as colorless solid (17. 20.9, 43.8, 44.9, 120.4 (q, J = 257.5 Hz), 121.3 (2C), 121.7, 124.9, 125.8, 128.4 (2C), 129.4, 129.5, 137.8, 141.9, 146.2, 149.2, 153.0; CDCl 3 1, 45.4, 52.2, 54.2, 122.8, 124.7, 127.0, 128.0, 129.0, 129.1 (2C), 129.7, 130.8, 131.3, 138.1, 139.7, 141.7, 147.6, 166.8 43.8, 45.0, 52.3, 121.8, 125.0, 125.9, 128.1, 129.0, 129.2, 129.5, 129.5, 130.9, 131.3, 139.4, 142.3, 146.3, 153.1, 166.7; Anal. calcd for C 19 H 17 N 3 O 2 S: C, 64.94; H, 4.88; N, 11.96. Found: C, 64.83; H, 4.79; N, 11.84. 3.1.47 Synthesis of 9-(3-Cyanophenyl)-3,4-dihydro-2H, 6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31j) N-(tert-Butyl)-9-(3-cyanophenyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29j). Using the general procedure as described for 22l, N-(tertbutyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2- 1, 45.4, 54.2, 113.2, 118.5, 122.8, 124.5, 127.6, 129.3, 129.7, 130.1, 130.5, 131.3, 131.4, 137.7, 140.4, 140.8, 147.4 Compound 31j. Using the general procedure as described for 25a, compound 29j (40.3 mg, 0.11 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (2:1 to 0:1) gave the title compound 31j as colorless solid ( 20.7, 43.9, 44.7, 113.0, 118.3, 121.9, 124.9, 126.2, 129.5, 129.7, 129.7, 130.4, 131.3, 131.5, 140.2, 141.0, 146.6, 153.4 3.1.48 Synthesis of 3,4-Dihydro-9-(3-nitrophenyl)-2H,6Hpyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31k) N-(tert-Butyl)-3,4-dihydro-9-(3-nitrophenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29k). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2- 2, 45.4, 54.3, 121.8, 122.7, 122.9, 124.6, 127.7, 129.4, 129.9, 130.2, 132.9, 137.6, 140.2, 141.1, 147.4, 148.7 5, 44.9, 45.5, 54.3, 119.1, 119.8, 122.9, 123.7, 124.8, 127.0, 129.0, 129.8, 130.1, 137.7, 137.9, 140.9, 142.0, 148.4 20.8, 39.1, 44.0, 44.7, 118.8, 120.0, 121.9, 123.4, 125.2, 125.6, 129.3, 129.5, 130.1, 138.0, 140.5, 142.7, 147.0, 153.9 3.1.52 Synthesis of 3,4-Dihydro-9-(3-hydroxyphenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31o) N-(tert-Butyl)-3,4-dihydro-9-(3-hydroxyphenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29o). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2- 5, 45.4, 54.2, 113.8, 115.1, 118.2, 122.8, 124.9, 126.0, 128.5, 129.4, 129.8, 138.1, 140.4, 143.2, 149.4, 157 43.8, 45.0, 55.4, 112.8, 113.6, 119.5, 121.8, 125.2, 125.6, 129.3, 129.3, 129.9, 140.6, 143.4, 146.4, 153.4, 160.0; Anal. calcd for C 18 H 17 N 3 OS: C, 66.85; H, 5.30; N, 12.99. Found: C, 66.56; H, 5.14; N, 12.83. 3.1.54 Synthesis of 3,4-Dihydro-9-(3-isopropoxyphenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31q) 3.1.55 Synthesis of 9-[(1,1 0 -Biphenyl)-3-yl]-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31r) 9-[(1,1 0 -Biphenyl)-3-yl]-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29r). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3-biphenylboronic acid (35.7 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 29r as a colorless oil ( Compound 31r. Using the general procedure as described for 25a, compound 29r (56.1 mg, 0.13 mmol) was allowed to react for 3 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 43.9, 45.0, 121.9, 125.2, 125.6, 125.9 (2C), 127.1, 127.2 (2C), 127.6, 128.8 (2C), 129.3, 129.4 (2C), 139.7, 140.8, 142.1, 143.4, 146.4, 153.3; HRMS (FAB) 3.1.56 Synthesis of 3,4-Dihydro-9-(2-methoxyphenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31s) N-(tert-Butyl)-3,4-dihydro-9-(2-methoxyphenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29s). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2- 1, 45.4, 54.1, 55.6, 111.4, 120.9, 125.2, 126.2, 127.5, 128.0, 128.6, 129.1, 129.3, 130.6, 138.6, 140.6, 147.9, 156.5 Compound 31s. Using the general procedure as described for 25a, compound 29s (34.7 mg, 0.091 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1 to 7:3) gave the title compound 31s as colorless solid (21.6 mg, 73 21.1, 43.8, 44.9, 55.6, 111.3, 120.9, 124.3, 125.1, 127.7, 128.3, 128.4, 128.7, 129.5, 130.5, 141.1, 146.6, 153.7, 156.4; Anal. calcd for C 18 H 17 N 3 OS: C, 66.85; H, 5.30; N, 12.99. Found: C, 66.56; H, 5.08; N, 12.90. 3.1.57 Synthesis of 9-[(1,1 0 -Biphenyl)-2-yl]-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31t) 9-[(1,1 0 -Biphenyl)-2-yl]-N-(tert-butyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (29t). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 2-biphenylboronic acid (35.7 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 29t as a colorless oil ( 1, 45.4, 54.1, 125.5, 125.9, 126.7, 127.5, 127.9, 127.9, 128.1, 128.1 (2C), 128.6, 129.7 (2C), 130.2, 130.7, 138.4, 138.9, 140.6, 140.9, 143.6, 147.8 Compound 31t. Using the general procedure as described for 25a, compound 29t (51.1 mg, 0.12 mmol) was allowed to react for 3 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1 to 7:3) gave the title compound 31t as a colorless oil (35.7 mg, 81 %): IR (neat) cm -1 : 1620 3.1.59 Synthesis of 3,4-Dihydro-9-(3,4,5-trimethoxyphenyl)-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31v) 3.1.60 Synthesis of 9-(3-Chloro-4-methoxyphenyl)-3,4dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6 -imine (31w) N-(ter t -Butyl)-9-(3-chloro-4-methoxyphenyl)-3,4-dihydro-2H,6H-pyrimido [1, 2-c] [1, 3] benzothiazin-6-imine (29w). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3-chloro-4methoxyphenylboronic acid (33.6 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 29w as a colorless oil ( 1, 45.4, 54.2, 56.2, 112.2, 122.2, 123.0, 124.3, 126.2, 126.4, 128.7, 129.0, 129.7, 132.7, 138.1, 141.2, 147.6, 155.0 Compound 31w. Using the general procedure as described for 25a, compound 29w (41.6 mg, 0.10 mmol) was allowed to react for 3 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (9:1 to 7:3) gave the title compound 31w as colorless solid (18.8 mg, 53 43.8, 44.9, 56.2, 112.2, 121.2, 123.0, 124.5, 125.3, 126.2, 128.7, 129.4, 129.5, 132.4, 141.7, 146.3, 153.2, 155 3.1.61 Synthesis of 9-(3-Chloro-6-methoxyphenyl)-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine (31x) N-(tert-Butyl)-9-(3-chloro-6-methoxyphenyl)-3,4-dihydro-2H,6H-pyrimido [1, 2-c] [1, 3] benzothiazin-6-imine (29x). Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido [1,2-c] [1, 3] benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3-chloro-6methoxyphenylboronic acid (33.6 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 29x as a colorless oil (54.9 mg, 88 %): IR (neat) cm 1, 45.4, 54.1, 55.9, 112.6, 125.1, 125.8, 126.7, 127.2, 128.1, 128.8, 128.8, 130.2, 130.6, 138.4, 139.2, 147.8, 155 Compound 31x. Using the general procedure as described for 25a, compound 29x (33.2 mg, 0.080 mmol) was allowed to react for 3 h. Purification by flash NMR (125 MHz, CDCl 3 ) d: 47.3, 52.9, 120.8, 123.8, 126.5, 129.1, 132.0, 132.4, 150.0, 154.0; HRMS (FAB) : m/z calcd for C 10 3.1.78 Synthesis of 6H,8H-Quinazolino [3,2-c] [1, 3] benzothiazin-6-imine (36b) N-(tert-Butyl)-6H,8H-quinazolino [3,2-c] [1, 3] benzothiazin-6-imine (35b). To a solution of 2-fluorobenzaldehyde (1.41 g, 11.39 mmol) in t-BuOH (38 mL) was added 2-aminobenzylamine 33b (1.53 g, 12. 53 mmol). The mixture was stirred at 80°C for 30 min, and then K 2 CO 3 (4.73 g, 34.18 mmol) and I 2 (3.61 g, 14. 24 mmol) were added. After being stirred at same temperature for 4 h, the mixture was quenched with sat. Na 2 SO 3 . The organic layer was separated and concentrated. The resulting solid was dissolved with H 2 O and CHCl 3 , and then pH was adjusted to 12-14 with 5 N NaOH. The whole was extracted with CHCl 3 . The extract was washed with brine, dried over Na 2 SO 4 . To a mixture of resulting residue in DMAc (7.4 mL) were added KOt-Bu (496 mg, 4.42 mmol) and tertbutylisothiocyanate (0.56 mL, 4.42 mmol) under an N 2 atmosphere. After being stirred at 80°C for 2.5 h, sat. NH 4 Cl was added. The whole was extracted with EtOAc. The extract was washed with brine, and dried over Na 2 SO 4 . After concentration, the residue was purified by flash chromatography over silica gel with nhexane-EtOAc (1:0 to 9:1) to give the title compound 2, 54.7, 124.0, 124.8, 124.9, 125.4, 125.8, 126.4, 127.7, 128.3, 129.0, 129.4, 130.7, 138.3, 141.1, 148.3; Anal. calcd for C 19 H 19 N 3 S: C, 70.99; H, 5.96; N, 13.07. Found: C, 71.05; H, 5.99; N, 12.91 . Compound 36b. TFA (0.5 mL) was added to 35b (100 mg, 0.311 mmol). After being stirred under reflux for 30 min, the mixture was added dropwise to Et 3 N at 0°C to adjust pH to 8-9. The whole was extracted with EtOAc. The extract was washed with sat. NaHCO 3 aq., brine, and dried over Na 2 SO 4 . After concentration, the residue was purified by preparative TLC over aluminum oxide with n-hexane-EtOAc (9:1) to give the title compound 36b as colorless solid (13 mg 1, 123.0, 123.8, 125.4, 125.6, 126.3, 126.5, 126.6, 128.5, 129.2, 129.5, 131.1, 140.1, 146.3, 153.3; HRMS (FAB) : m/z calcd for C 15 Ar), 8.34 (d, J = 8.6 Hz, 1H, Ar), 8.42 (t, J = 1.7 Hz, 1H, Ar); 13 C-NMR (125 MHz 49 Synthesis of 20 mmol) was allowed to react with 3-vinylphenylboronic acid (35.5 mg, 0.24 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 29l as a colorless oil (64.4 mg, 86 %): IR (neat) cm -1 : 1591 (C=N); 1 H-NMR (500 MHz IR (neat) cm -1 : 1616 (C=N) Synthesis of 9 Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3-(acetylamino)phenylboronic acid (32.2 mg, 0.18 mmol) in 1,4-dioxane for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:1) gave the title compound 29m as colorless solid (44.6 mg 18 (s, 3H, CH 3 ), 3.64 (t, J = 5.4 Hz, 2H, CH 2 ), 3.89 (t, J = 6.0 Hz 06 (s, 3H, CH 3 ), 3.60 (t, J = 5.4 Hz, 2H, CH 2 ), 3.93 (t, J = 6.0 Hz, 2H, CH 2 ) Synthesis of 3,4-Dihydro-9 Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3] benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3-(methanesulfonylamino)phenylboronic acid (38.7 mg, 0.18 mmol) in 1,4-dioxane Compound 31o. TFA (9 mL) was added to a mixture of 29o (16.1 mg, 0.044 mmol) and MS4Å (2.0 g, powder, activated by heating with Bunsen burner) in CHCl 3 (1.0 mL) and MeOH (10 drops) IR (neat) cm -1 : 1621 (C=N), 1557 (C=N); 1 H-NMR (500 MHz, DMSO-d 6 ) d: 1.85-1.90 (m, 2H, CH 2 ), 3.60 (t, J = 5.4 Hz, 2H, CH 2 ), 3.92 (t, J = 5.4 Hz, 2H, CH 2 ), 6.81 (dd, J = 7.7, 2.0 Hz, 1H, Ar), 7.06 (t, J = 2.0 Hz, 1H, Ar), 7.13 (d, J = 8.3 Hz, 1H, Ar), 7.27 (t, J = 7.7 Hz, 1H, Ar), 7.48-7.50 (m, 2H, Ar) Synthesis of 3,4-Dihydro-9-(4-methoxyphenyl)-2H,6H-pyrimido[1,2-c 15 mmol) was allowed to react with 4-methoxyphenylboronic acid (27.4 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 29p as a colorless oil (55.6 mg, 98 %): IR (neat) cm -1 : 1591 (C=N); 1 H-NMR (400 MHz C=N); 1 H-NMR (400 MHz Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3-isopropoxyphenylboronic acid (32.4 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc ): m/z calcd for C 24 H 30 N 3 OS [M ? H] + 408.2110; found: 408.2108. Compound 31q. Using the general procedure as described for 25a, compound 29q (44.0 mg, 0.108 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane CH 2 ), 3.99 (t, J = 6.1 Hz, 2H, CH 2 ), 6.83 (d, J = 1.7 Hz, 1H, Ar), 6.95 (dd Synthesis of 3,4-Dihydro-9 Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3,4-dimethoxyphenylboronic acid (32.8 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc IR (neat) cm -1 : 1593 (C=N) CH 2 ), 3.89 (t, J = 6.1 Hz, 2H, CH 2 ), 3.92 (s, 3H, CH 3 ), 3.96 (s, 3H, CH 3 ), 6.93 (d, J = 8.3 Hz, 1H, Ar), 7.09 (d, J = 2.0 Hz, 1H, Ar), 7.15 (dd 11 mmol) was allowed to react for 3 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 92 (s, 3H, CH 3 ), 3.96 (s, 3H, CH 3 ), 4.04 (t, J = 6.2 Hz, 2H, CH 2 ), 6.93 (d, J = 8.3 Hz, 1H, Ar), 7.07 (d, J = 2.0 Hz, 1H, Ar), 7.14 (dd Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3,4,5-trimethoxyphenylboronic acid (38.2 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc CH 2 ), 3.88-3.91 (m, 5H, CH 3 , CH 2 ), 3.93 (s, 6H, 2 9 CH 3 ), 6.77 (s, 2H, Ar), 7.28 (d, J = 1.8 Hz, 1H, Ar), 7.38 (dd Using the general procedure as described for 25a, compound 29v (49.4 mg, 0.11 mmol) was allowed to react for 3 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc IR (neat) cm -1 : 1620 (C=N) 89 (s, 3H, CH 3 ), 3.93 (s, 6H, 2 9 CH 3 ), 4.04 (t, J = 6.1 Hz, 2H, CH 2 ), 6.75 (s, 2H, Ar) HRMS (FAB): m/z calcd for C 20 H 22 N 3 O 3 S IR (neat) cm -1 : 1620 (C=N) 79 (s, 3H, CH 3 ), 4.04 (t, J = 6.2 Hz, 2H, CH 2 ), 6.89 (d, J = 8.5 Hz Synthesis of 3,4-Dihydro-9-(naphthalen-2-yl)-2H, 6H-pyrimido[1,2-c Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 2-naphthaleneboronic acid (30.9 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc CDCl 3 ) d: 1.42 (s, 9H, 3 9 CH 3 ), 1.91-1.96 (m, 2H, CH 2 ), 3.65 (t, J = 5.2 Hz, 2H ): m/z calcd for C 25 H 26 N 3 S [M ? H] + 400.1847; found: 400.1848. Compound 32a. Using the general procedure as described for 25a, compound 30a (45.3 mg, 0.11 mmol) was allowed to react for 3 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc IR (neat) cm -1 : 1620 (C=N) HRMS (FAB): m/z calcd for C 21 H 18 N 3 S Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 1-naphthaleneboronic acid (30.9 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (m, 2H, CH 2 ), 3.67 (t, J = 5.6 Hz, 2H, CH 2 ), 3.92 (t 12 mmol) was allowed to react for 3 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc IR (neat) cm -1 : 1620 (C=N) 33 (d, J = 8.3 Hz, 1H, Ar); 13 C-NMR (100 MHz 4-methylenedioxyphenyl)-2H,6H-pyrimido[1,2-c Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3,4-(methylenedioxy)phenylboronic acid (29.9 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 99 (s, 2H, CH 2 ), 6.87 (d, J = 8.8 Hz, 1H, Ar), 7.05-7.07 (m, 2H, Ar), 7.24 (d, J = 2.0 Hz, 1H, Ar), 7.34 (dd, J = 8.3, 2.0 Hz, 1H, Ar), 8.21 (d, J = 8.3 Hz, 1H, Ar); 13 C-NMR (100 MHz IR (neat) cm -1 : 1619 (C=N) CH 2 ), 6.00 (s, 2H, CH 2 ) ]dioxin-6-yl)boronic acid (32.3 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:0 to 9:1) gave the title compound 30d as a colorless oil (63.9 mg, 96 %): IR (neat) cm -1 : 1586 (C=N); 1 H-NMR (500 MHz IR (neat) cm -1 : 1619 (C=N) CH 2 ), 4.28 (s, 4H, 2 9 CH 2 ), 6.92 (d, J = 8.6 Hz, 1H, Ar), 7.06 (dd, J = 8.6, 2.3 Hz, 1H, Ar), 7.09 (d, J = 2.3 Hz, 1H, Ar), 7.17 (d, J = 2.0 Hz, 1H, Ar), 7.19 (br s, 1H, NH), 7.38 (dd Synthesis of 3,4-Dihydro-9-(quinolin-6-yl)-2H, 6H-pyrimido[1,2-c 4-dihydro-9-(quinolin-6-yl)-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine (30e) 15 mmol) was allowed to react with 6-quinolineboronic acid (31.1 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 55 (dd, J = 8.3, 1.8 Hz, 1H, Ar), 7.95 (dd, J = 8.8, 2.0 Hz, 1H, Ar), 8.00 (d, J = 1.5 Hz, 1H, Ar), 8.16-8.21 (m, 2H, Ar), 8.32 (d, J = 8.3 Hz, 1H, Ar), 8.93 (dd, J = 4.1, 1.5 Hz, 1H, Ar); 13 C-NMR (100 MHz IR (neat) cm -1 : 1620 (C=N) 7.58 (dd, J = 8.3, 1.7 Hz, 1H, Ar) Synthesis of 3,4-Dihydro-9 4-dihydro-9-(indol-6-yl)-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine (30f) 15 mmol) was allowed to react with indol-6-ylboronic acid (29.0 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (2:1) gave the title compound 30f as colorless solid (56.0 mg IR (neat) cm -1 : 1589 (C=N); 1 H-NMR (500 MHz, DMSO-d 6 ) d: 1.39 (s, 9H, 3 9 CH 3 ) activated by heating with Bunsen burner) was extracted with EtOAc. The extract was washed with sat. NaHCO 3 , brine, and dried over MgSO 4 . After concentration, the residue was purified by preparative TLC over aluminum oxide 88 (s, 1H, Ar), 8.24-8.28 (m, 2H, Ar), 8.55 (d HRMS (FAB): m/z calcd for C 21 H 16 F 3 N 4 OS Using the general procedure as described for 22l 15 mmol) was allowed to react with indol-5-ylboronic acid (29.0 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (2:1) gave the title compound 30g as colorless solid (59.2 mg TFA (17 mL) was added to a mixture of 30g (28.5 mg, 0.073 mmol) and MS4Å (4.5 g, powder, activated by heating with Bunsen burner) whole was extracted with EtOAc. The extract was washed with sat IR (neat) cm -1 : 1659 (C=O), 1613 (C=N), 1561 (C=N); 1 H-NMR (500 MHz, DMSO-d 6 ) d: 1.86-1.91 (m, 2H, CH 2 ), 3.61 (t, J = 5.4 Hz, 2H, CH 2 ), 3.94 (t, J = 5.7 Hz, 2H, CH 2 ), 7.56-7.59 (m, 2H, Ar) HRMS (FAB): m/z calcd for C 21 H 16 F 3 N 4 OS Synthesis of 3,4-Dihydro-9-(pyridin-3-yl)-2H, 6H-pyrimido[1,2-c Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 3-pyridineboronic acid (22.1 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 41 (dd, J = 8.5, 1.7 Hz, 1H, Ar), 7.87 (ddd, J = 7.8, 2.2, 1.5 Hz, 1H, Ar), 8.30 (d, J = 8.5 Hz, 1H, Ar), 8.62 (dd, J = 4.9, 1.5 Hz, 1H, Ar), 8.85 (d, J = 2.2 Hz, 1H, Ar); 13 C-NMR (100 MHz CDCl 3 ) d: 1.97-2.03 (m, 2H, CH 2 ), 3.72 (t, J = 5.5 Hz, 2H, CH 2 ), 4.05 (t, J = 6.1 Hz, 2H, CH 2 ), 7.24 (d, J = 1.7 Hz, 1H, Ar), 7.38 (dd, J = 7.9, 4.8 Hz, 1H, Ar), 7.43 (dd, J = 8.3, 1.7 Hz, 1H, Ar) Synthesis of 3,4-Dihydro-9 -yl)-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine (30i) 15 mmol) was allowed to react with 4-pyridineboronic acid (22.1 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc CH 2 ), 3.65 (t, J = 5.4 Hz, 2H, CH 2 ), 3.89 (t, J = 6.0 Hz, 2H, CH 2 ), 7.38 (s, 1H, Ar), 7.45 (d, J = 8.6 Hz, 1H, Ar), 7.49 (d, J = 5.0 Hz, 2H, Ar), 8.30 (d, J = 8.6 Hz, 1H, Ar), 8.67 (d, J = 5.0 Hz, 2H, Ar); 13 C-NMR (100 MHz Using the general procedure as described for 25a, compound 30i (23.4 mg, 0.067 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:1 to 0:1) gave the title compound 32i as colorless solid (15.1 mg IR (neat) cm -1 : 1620 (C=N) 29 (s, 1H, Ar), 7.46-7.48 (m, 3H, Ar), 8.33 (d, J = 8.6 Hz, 1H, Ar), 8.68 (d, J = 4.6 Hz, 2H, Ar); 13 C-NMR (100 MHz Synthesis of 9-(Furan-2-yl)-3,4-dihydro-2H, 6H-pyrimido[1,2-c Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 2-furanboronic acid (20.1 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc Using the general procedure as described for 25a, compound 30j (30.3 mg, 0.089 mmol) was allowed to react for 4 h with TFA (1.0 mL) and MS4Å (150 mg) CDCl 3 ) d: 1.95-2.01 (m, 2H, CH 2 ), 3.70 (t, J = 5.6 Hz, 2H, CH 2 ), 4.02 (t, J = 6.1 Hz, 2H, CH 2 ), 6.49 (dd Synthesis of 9-(Benzofuran-2-yl)-3,4-dihydro-2H, 6H-pyrimido[1,2-c ] benzothiazin-6-imine (30k) Using the general procedure as described for 22l, N-(tertbutyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 2-benzofuranboronic acid (29.2 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (m, 2H, Ar), 8.25 (d, J = 8.0 Hz, 1H, Ar); 13 C-NMR (125 MHz IR (neat) cm -1 : 1620 (C=N) 2H, CH 2 ), 7.07 (s, 1H, Ar), 7.22-7.25 (m, 1H, Ar), 7.31 (t, J = 7.2 Hz, 1H, Ar), 7.50-7.51 (m, 2H, Ar), 7.58 (d, J = 7.2 Hz Synthesis of 3,4-Dihydro-9-(thiophen-3-yl)-2H, 6H-pyrimido[1,2-c -yl)-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine (30l) 15 mmol) was allowed to react with 3-thiopheneboronic acid (23.0 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc IR (neat) cm -1 : 1592 (C=N) CH 2 ), 3.88 (t, J = 6.2 Hz, 2H, CH 2 ), 7.32 (d, J = 2.0 Hz, 1H, Ar), 7.36-7.43 (m, 3H, Ar), 7.50 (dd, J = 2.7, 1.5 Hz, 1H, Ar), 8.21 (d, J = 8.5 Hz, 1H, Ar); 13 C-NMR (100 MHz, CDCl 3 ) d: 21.9 IR (neat) cm -1 : 1619 (C=N), 1569 (C=N); 1 H-NMR (400 MHz, CDCl 3 ) d: 1.96-2.01 (m, 2H, CH 2 ), 3.70 (t, J = 5.4 Hz, 2H, CH 2 ), 4.03 (t, J = 6.1 Hz, 2H, CH 2 ), 7.23 (d, J = 1.1 Hz, 1H, Ar), 7.35-7.41 (m, 2H, Ar), 7.44 (dd, J = 8.3, 1.1 Hz, 1H, Ar), 7.51-7.52 (m, 1H, Ar) Synthesis of 9-(Benzothiophen-2-yl)-3,4-dihydro-2H,6H-pyrimido Using the general procedure as described for 22l, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with 2-benzothiopheneboronic acid (32.0 mg, 0.18 mmol) for 1 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc CDCl 3 ) d: 1.41 (s, 9H, 3 9 CH 3 ), 1.90-1.94 (m, 2H, CH 2 ), 3.63 (t Using the general procedure as described for 25a, compound 30m (35.8 mg, 0.09 mmol) was allowed to react for 3 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc IR (neat) cm -1 : 1615 (C=N) OD) d: 1.95-2.00 (m, 2H, CH 2 ), 3.69 (t, J = 5.4 Hz, 2H, CH 2 ), 4.01 (t, J = 6.0 Hz, 2H, CH 2 ), 7.25 (br s, 1H, NH), 7.32-7.37 (m, 3H, Ar), 7.54 (dd, J = 8.6, 1.7 Hz, 1H, Ar), 7.58 (s, 1H, Ar), 7.77 (t, J = 4.0 Hz, 1H, Ar), 7.82 (d, J = 7.4 Hz Synthesis of 3,4-Dihydro-9-(1H-pyrazol-1-yl)-2H, 6H-pyrimido[1,2-c To a solution of N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol), pyrazole (12.3 mg, 0.18 mmol), CuCl (1.5 mg, 0.015 mmol) and K 2 CO 3 (21.8 mg, 0.16 mol) in N-methylpyrrolidone (0.3 mL) was added acetylacetone (3.8 lL, 0.038 mmol) under an Ar atmosphere. After being stirred at 130°C for 19 h, EtOAc was added. The organic layers were washed with H 2 O CH 2 ), 3.88 (t, J = 6.2 Hz, 2H, CH 2 ), 6.48 (dd, J = 2.7, 1.8 Hz, 1H, Ar), 7.47 (dd Using the general procedure as described for 25a, compound 30n (21.6 mg, 0.064 mmol) was allowed to react for 1 h CDCl 3 ) d: 1.96-2.02 (m, 2H, CH 2 ), 3.70 (t, J = 5.6 Hz, 2H, CH 2 ), 4.03 (t, J = 6.2 Hz, 2H, CH 2 ), 6.49 (dd Synthesis of 3,4-Dihydro-9-(1H-imidazol-1-yl)-2H,6H-pyrimido[1,2-c Using the general procedure as described for 30n, N-(tert-butyl)-9-bromo-3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine 22k (52.8 mg, 0.15 mmol) was allowed to react with imidazole (12.3 mg, 0.18 mmol) for 3 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc CH 2 ), 3.89 (t, J = 6.2 Hz, 2H, CH 2 ), 7.15 (d, J = 2.3 Hz, 1H, Ar), 7.22 (dd, J = 8.8, 2.3 Hz, 1H, Ar), 7.22 (s, 1H, Ar), 7.30 (s, 1H, Ar), 7.90 (s, 1H, Ar), 8.32 (d, J = 8.8 Hz, 1H, Ar); 13 C-NMR (100 MHz IR (neat) cm -1 : 1622 (C=N), 1561 (C=N); 1 H-NMR (400 MHz, CDCl 3 ) d: 1.97-2.03 (m, 2H, CH 2 ) Synthesis of 2,3-Dihydro-5H-imidazo[1,2-c Using the general procedure as described for 25a, N-(tert-butyl)-2,3-dihydroimidazo[1,2-c][1,3]benzothiazin-5-imine 35a (18.4 mg, 0.07 mmol) was allowed to react for 12 h with TFA (1.0 mL) and MS4Å (150 mg). Purification by flash chromatography over silica gel with n-hexane-EtOAc (1:1) gave the title compound 36a as colorless solid (11.1 mg CDCl 3 ) d: 4.11 (4H, s, 2 9 CH 2 ) 2-Fluorobenzaldehyde (0.62 g, 5.0 mmol) was subjected to the general procedure for 18j using 2-methylpropylenediamine 33c 1H, br s, NH), 7.04 (1H, dd, J = 11.7, 8.3 Hz, Ar), 7.15 (1H, t, J = 7.4 Hz, Ar), 7.30-7.35 (1H, m, Ar) Using the general procedure as described for 22e, compound 34c (384.5 mg, 2.0 mmol) was allowed to react at 80°C for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc IR (neat) cm -1 : 1598 (C=N), 1570 (C=N) CH 3 ), 1.39 (9H, s, 3 9 CH 3 ), 1.91-1.99 (1H, m, CH), 3.09-3.17 (2H, m, CH 2 ), 3.72 (1H, dt ): m/z calcd for C 16 H 22 N 3 S [M ? H] + 288.1534; found: 288.1535. Compound 36c. Using the general procedure as described for 25a 1574 (C=N); 1 H-NMR (500 MHz 27 (1H, dd 1H, d, J = 7.4 Hz, Ar), 7.18-7.25 (2H, m, Ar, NH), 7.33 (1H, td, J = 7.4, 1.4 Hz, Ar) Synthesis of 3,4-Dihydro-3,3-dimethyl-2H, 6H-pyrimido 2-Fluorobenzaldehyde (0.62 g, 5.0 mmol) was subjected to the general procedure for 18j using 2,2-dimethylpropylenediamine Using the general procedure as described for 22e, compound 34d (412.5 mg, 2.0 mmol) was allowed to react at 80°C for 2 h IR (neat) cm -1 : 1602 (C=N) 20 (1H, t, J = 8.0 Hz, Ar), 7.31 (1H, td, J = 8.0, 1.1 Hz, Ar), 8.21 (1H, dd, J = 8.0, 1.1 Hz, Ar); 13 C-NMR (125 MHz C=N); 1 H-NMR (500 MHz 26 (1H, dd, J = 8.3, 1.4 Hz, Ar); 13 C-NMR (125 MHz HRMS (FAB): m/z calcd for C 13 H 16 N 3 S To a solution of 2-fluorobenzaldehyde (2.48 g, 20.0 mmol) in t-BuOH (188 mL) was added 1,4-diaminobutane 33e (2.21 mL, 22.0 mmol). The mixture was stirred at 70°C for 30 min After being stirred at same temperature for 3 h, the mixture was quenched with sat. Na 2 SO 3 . The organic layer was separated and concentrated. The resulting solid was dissolved with H 2 O, and then pH was adjusted to 12-14 with 2 N NaOH. The whole was extracted with CHCl 3 , and dried over Na 2 After being stirred at rt for 1 h, the whole was extracted with CHCl 3 . The extract was washed with brine, and dried over MgSO 4 . After concentration, the residue was purified by column chromatography over silica gel with n-hexane-EtOAc CDCl 3 ) d: 1.14 (9H, s, 3 9 CH 3 ), 1.66-1.70 (2H, m, CH 2 ), 1.78-1.83 (2H, m, CH 2 ), 3.61 (2H, br s To a solution of 37 (877.1 mg, 3.0 mmol) in CH 2 Cl 2 (6.0 mL) was added TFA (6.0 mL). The mixture was stirred under reflux for 2 h, mixture was washed with 2 N NaOH. The organic phase was dried over Using the general procedure as described for 25e, compound 34e (192.2 mg, 1.0 mmol) was allowed to react at rt overnight. Purification by flash chromatography over silica gel with n-hexane-EtOAc 1.87-1.93 (4H, m, 2 9 CH 2 ), 3.82 (2H, t, J = 5.4 Hz, CH 2 ), 3.88 (2H, t, J = 5.4 Hz, CH 2 ), 7.16-7.23 (2H, m, Ar), 7.26-7.31 (1H, m, Ar) Using the general procedure as described for 25a, compound 35e (50.3 mg, 0.18 mmol) was allowed to react for 2 h. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (4:1 to 2:1) gave the title compound 36e as a colorless oil (11.3 mg, 27 %): IR (neat) cm -1 : 1638 (C=N), 1578 (C=N); 1 H-NMR (400 MHz Synthesis of 9-Bromo-2H-spiro After being stirred at the same temperature for additional 5 h, EtOAc was added. The mixture was washed with 5 % aq. NaHCO 3 , and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over silica gel with n-hexane-EtOAc (3:1). The resulting solid was recrystalized from CHCl 3 -n-hexane to give the title compound 42 as colorless crystals (801.8 mg, 60 %): mp 62°C, IR (neat) cm -1 : 2254 (C : N); 1 H-NMR (400 MHz MS (FAB) m/z (%): 135 (MH + After being stirred at 65°C for 5 h, the reaction mixture was cooled to 0°C, and was added 1 N HCl. After being stirred at rt for 1 h, the mixture was basified with 2 N NaOH. The whole was extracted with CHCl 3 and dried over MgSO 4 . After concentration, the residue was dissolved in t-BuOH (10.0 mL), and 4-bromo-2-fluorobenzaldehyde (203.0 mg, 1.0 mmol) was added. After being stirred at 70°C for 30 min Na 2 SO 3 until the iodine color almost disappeared. The reaction mixture was basified with 2 N NaOH. The whole was extracted with CHCl 3 , and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over aluminum oxide with CDCl 3 ) d: 21.7 (2C), 26.5, 28.8 (2C), 33.5, 52.2 (2C), 119.4 (d, J = 27.6 Hz), 123.1 (d, J = 12.0 Hz), 123.5 (d, J = 10.8 Hz), 127.7 (d, J = 3.6 Hz), 131.8 (d, J = 3.6 Hz), 149.9, 159.8 (d, J = 251.9 Hz); 19 F-NMR (500 MHz, CDCl 3 ) d: -114.6; HRMS (FAB): m/z calcd for C 15 H 19 BrFN 2 [M ? H] + 325.0716; found: 325.0724. 9-Bromo-N-(tert-butyl)-2H-spiro IR (neat) cm -1 : 1578 Using the general procedure as described for 25a, 48 (124.7 mg, 0.3 mmol) was allowed to react under reflux for 2.5 h with TFA (3.0 mL) and MS4Å (0.45 g). Purification by flash chromatography over aluminum oxide C=N); 1 H-NMR (400 MHz 24 (s, 1H, NH), 7.33 (dd, J = 8.8, 2.0 Hz, 1H, Ar), 8.10 (d, J = 8.8 Hz, 1H, Ar); 13 C-NMR (100 MHz To a solution of malononitrile (660.6 mg, 10.0 mmol) in DMF (25.0 mL) was added DBU (2.99 mL, 20.0 mmol) NaHCO 3 , and dried over MgSO 4 . The filtrate was concentrated. The residue was purified by flash chromatography over silica gel with n-hexane-EtOAc (3:1). The resulting solid was recrystalized from CHCl 3 -nhexane to give the title compound 43 as colorless crystals (112.2 mg, 8 %): mp 96°C, IR (neat) cm -1 : 2253 (C : N); 1 H-NMR (400 MHz CDCl 3 ) d: 30.2, 33.8 (2C), 63.0 (2C) MS (FAB) m/z (%) -Bromo-2-fluorophenyl)-9-oxa-2,4-diazaspiro Using the general procedure as described for 45, 43 (84.1 mg, 0.62 mmol) was allowed to react 31 (s, 4H, 2 9 CH 2 ), 3.72 (t, J = 5.4 Hz, 4H, 2 9 CH 2 ), 4.03 (br s, 1H, NH), 7.25 (dd, J = 11.7, 2.0 Hz, 1H, Ar), 7.31 (dd Using the general procedure as described for 48, 46 (21.4 mg, 0.065 mmol) was allowed to react at rt overnight. Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 9 CH 2 ), 3.48 (s, 2H, CH 2 ), 3.71-3.74 (m, 4H, 2 9 CH 2 ), 3.84 (s, 2H Using the general procedure as described for 25a, 50 (21.4 mg, 0.065 mmol) was allowed to react under reflux for 2.5 h with TFA (1.0 mL) and MS4Å (150 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 56 (s, 2H, CH 2 ), 3.74 (t, J = 5.4 Hz, 4H, 2 9 CH 2 ), 3.93 (s, 2H, CH 2 ), 7.22 (d, J = 2.0 Hz, 1H, Ar) HRMS (FAB): m/z calcd for C 15 H 17 BrN 3 OS Synthesis of 9-Bromo-1 0 -(4-methoxybenzyl)-2H-spiro NaHCO 3 , brine, and dried over MgSO 4 . After concentration, the residue was dissolved in anhydrous Et 2 O (250 mL), and LiAlH 4 (2.1 g, 55.0 mmol) was slowly added to the mixture at 0°C under an Ar atmosphere. After being stirred at rt overnight, the reaction mixture was quenched by the addition of water, 2 N NaOH, and water. The mixture was dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over silica gel 88 mg, 37.7 mmol) in DMF (37.7 mL) was added. After being stirred at same temperature for 5 h, EtOAc was added. The mixture was washed with 5 % aq. NaHCO 3 , and dried over MgSO 4 . After concentration, the residue was purified by flash chromatography over silica gel with n-hexane-EtOAc (2:1) to give the title compound 44 as yellow oil (8.13 g, 85 %): IR (neat) cm -1 : 2248 (C : N); 1 H-NMR (400 MHz 05 g, 15.9 mmol) was allowed to react. Purification by flash chromatography over aluminum oxide with EtOAc-MeOH (1:0 to 95:5) to give the title compound 47 as colorless solid (752.6 mg, 11 %): mp 179-181°C (from CHCl 3 -n-hexane), IR (neat) cm -1 : 1630 (C=N); 1 H-NMR (500 MHz IR (neat) cm -1 : 1577 (C=N); 1 H-NMR 41 (s, 2H, CH 2 ), 3.47 (s, 2H, CH 2 ), 3.75 (s, 2H, CH 2 ), 3.80 (s, 3H, CH 3 ), 6.85 (d Using the general procedure as described for 25a, compound 52a (448.1 mg, 0.83 mmol) was allowed to react for 2 h with TFA (10.0 mL) and MS4Å (1.50 g). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (7:3) gave the title compound 53a as colorless solid (288.8 mg 46 (s, 2H, CH 2 ), 3.48 (s, 2H, CH 2 ), 3.79 (s, 3H, CH 3 ), 3.86 (s, 2H, CH 2 ), 6.84 (d, J = 8.8 Hz Synthesis of 9-Bromo-1 0 -(methoxycarbonyl)-2H-spiro ]thiazine-3,4 0 -piperidin)-6(4H)-imine 52a (40.6 mg, 0.075 mmol) in CH 2 Cl 2 (0.38 mL) was added methyl chloroformate (86.4 lL, 1.13 mmol) at 0°C under an Ar atmosphere. After being stirred at same temperature for 30 min, the reaction mixture was concentrated. The residue was purified by flash chromatography over silica gel with n-hexane-EtOAc CDCl 3 ) d: 1.37 (s, 9H, 3 9 CH 3 ), 1.46 (t, J = 5.6 Hz, 4H, 2 9 CH 2 ), 3.44 (br s, 4H, 2 9 CH 2 ), 3.56 (br s, 2H, CH 2 ), 3.70 (s, 3H, CH 3 ), 3.81 (s, 2H, CH 2 Using the general procedure as described for 25a, compound 52b (6.4 mg, 0.013 mmol) was allowed to react for 2 h with TFA (1.0 mL) and MS4Å (150 mg). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc 9 CH 2 ), 3.45-3.57 (m, 6H, 3 9 CH 2 ), 3.70 (s, 3H, CH 3 ), 3.91 (s, 2H, CH 2 ), 7.22 (d, J = 2.0 Hz, 1H, Ar) HRMS (FAB): m/z calcd for C 17 H 20 BrN 4 O 2 was allowed to react for 10 min with AcCl (53.3 lL, 0.75 mmol). Purification by flash chromatography over aluminum oxide with n-hexane-EtOAc (1:1) gave the title compound 52c as colorless solid (33.3 mg, 96 %) IR (neat) cm -1 : 1632 (C=O) (m, 4H, 2 9 CH 2 ), 2.10 (s, 3H, CH 3 ), 3.45-3.56 (m, 5H Compound 53c. Using the general procedure as described for 25a, compound 52c (6.5 mg, 0.014 mmol) was allowed to react for 2 h with TFA (1.0 mL) and MS4 Å (150 mg). Purification by flash chromatography over aluminum oxide CDCl 3 ) d: 1.49-1.55 (m, 4H, 2 9 CH 2 ), 2.09 (s, 3H, CH 3 ), 3.47-3.61 (m, 5H Synthesis of 9-Bromo-1 0 -(methanesulfonyl)-2H-spiro (4H)-imine 52a (54.2 mg, 0.10 mmol) in CH 2 Cl 2 (0.5 mL) were added Et 3 N (28.9 lL, 0.20 mmol) and 1-chloroethyl chloroformate (21.8 lL, 0.20 mmol) at 0°C under an Ar atmosphere IR (neat) cm -1 : 1577 (C=N), 1331 (NSO 2 ) 27 (m, 2H, CH 2 ), 3.31-3.37 (m, 2H, CH 2 ), 3.46 (s, 2H, CH 2 ), 3.84 (s, 2H, CH 2 ), 7.29-7.33 (m, 2H, Ar), 8.05 (d, J = 8.5 Hz, 1H, Ar); 13 C-NMR (100 MHz 82 (s, 3H, CH 3 ), 3.19-3.25 (m, 2H, CH 2 ), 3.35-3.41 (m, 2H, CH 2 ), 3.52 (s, 2H, CH 2 ), 3.92 (s, 2H, CH 2 ), 7.24 (d, J = 2.0 Hz Synthesis of 1 0 -(Aminocarbonyl)-9-bromo-2H-spiro Aminocarbonyl)-9-bromo-N-(tert-butyl)-2H-spiro Using the general procedure as described for 52d (4H)-imine 52a (54.2 mg, 0.10 mmol) was allowed to react with 1-chloroethyl chloroformate (21.8 lL, 0.20 mmol) followed with N-trimethylsilylisocyanate (26.5 lL, 0.20 mmol). Purification by flash chromatography over aluminum oxide with EtOAc-MeOH (1:0 to 9:1) gave the title compound 52e as colorless solid (11.8 mg IR (neat) cm -1 : 1649 (C=O) Using the general procedure as described for 25a, compound 52e (5.1 mg, 0.011 mmol) was allowed to react for 2 h with TFA (1.0 mL) and MS4Å (150 mg). Purification by flash chromatography over aluminum oxide with m, 4H, 2 9 CH 2 ), 3.45 (s, 2H, CH 2 ), 3.84 (s, 2H, CH 2 ), 5.88 (s, 2H, NH 2 The sensitivity of HIV-1 IIIB strain was determined by the MAGI assay. The target cells (HeLa-CD4/CCR5-LTR/b-gal; 10 4 cells/well) were plated in 96-well flat microtiter culture plates. On the following day, the cells were inoculated with the HIV-1 (60 MAGI U/well, giving 60 blue cells after 48 h of incubation) and cultured in the presence of various concentrations of the test compounds in fresh medium. Forty-eight hours after viral exposure, all the blue cells stained with X-Gal (5-bromo-4-chloro-3-indolyl-b-D-galactopyranoside) were counted in each well. The activity of test compounds was determined as the concentration that blocked HIV-1 infection by 50 % (50 % effective concentration [EC 50 ]). EC 50 was determined by using the following formula:EC 50 = 10^[log(A/B) 9 (50 -C)/(D -C) ? log(B)], wherein A: of the two points on the graph which bracket 50 % inhibition, the higher concentration of the test compound, B: of the two points on the graph which bracket 50 % inhibition, the lower concentration of the test compound, C: inhibitory activity (%) at the concentration B, D: inhibitory activity (%) at the concentration A.