174 Chapter 5 CHAPTER-5: New Synthetic Procedure to Prepare Olanzapine along. and popularly used as a medication for the treatment of psychotic

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1 174 CHAPTER-5: New Synthetic Procedure to Prepare Olanzapine along with its Related Compounds. 5.1: Introduction Olanzapine 83 (26) is one of the known atypical antipsychotic drug and popularly used as a medication for the treatment of psychotic diseases in many countries. It has a profile of activity in invitro binding assays similar to that of the atypical antipsychotic agent Clozapine. Olanzapine was approved by the FDA in the year 1996 in United States of America. Olanzapine exhibits high levels of activity at surprisingly low dosage levels, making the drug highly desirable therapeutic candidate for the treatment of psychotic patients. The mechanism of action of Olanzapine 84 as with other drugs having efficacy in schizophrenia is unknown. However, it has been proposed that this drug s efficacy in schizophrenia is mediated through a combination of dopamine and serotonin type 2 (5HT2) antagonism. The mechanism of action of Olanzapine in the treatment of acute manic or mixed episodes associated with bipolar I disorder is unknown. It displays a broad pharmacological profile and is a selective monoaminergic antagonist with high binding affinity to serotonin 5HT2A/2C, dopamine D14, muscrinic M1-5 and adrenergic α1 receptors.

2 Table-5.1 Product details 175 Name of the drug Active ingredient Innovator Marketed by Brand Name Olanzapine Olanzapine Eli Lilly Eli Lilly Zyprexa Structure Chemical name 2-Methyl-4-(4-methyl-1-piperazinyl)-10Hthieno[2,3-b][1,5]benzodiazepine Molecular formula C17H20N4S Molecular Weight Melting point º C CAS No Approved Indication Solubility Zyprexa is indicated for (i) the treatment of schizophrenia. (ii) the treatment of acute mixed or manic episodes associated with Bipolar I disorder. Soluble in acetonitrile and practically insoluble in water

3 : Reported Synthetic Schemes of Olanzapine The first reported synthesis 85 of Olanzapine (26) by Chakrabarti et al., involves the reaction of (scheme 5.1) 2-fluoronitrobenzene (121) with 2-amino-5-methylthiophene-3-carbonitrile (122) in the presence of sodium hydride and THF to give 2-(2-nitroanilino)-5-methyl thiophene-3- carbonitrile (123). The nitrile group of thiophene derivative 123 was catalytically hydrogenated and followed by treatment with ethanol to get an amino ester 124, which was then reacted with N-methyl piperazine (125) to give the amino amide 126 followed by cyclization in the presence of titanium tetrachloride to give the desired compound 26. Scheme 5.1 David O. Calligaro et al., disclosed two methods 86 (schemes 5.2 & 5.3) for the synthesis of Olanzapine. Scheme 5.2 involves the reaction of 2-Chloronitrobenzene (127) with 2-amino-5-methylthiophene-3-

4 177 carbonitrile (122) in the presence of lithium hydroxide to give the 2-(2- nitroanilino)-5-methyl thiophene-3-carbonitrile (123) which was reduced in the presence of stannous chloride and cyclized with HCl to afford benzodiazepine derivative 128 in the form of HCl salt. The benzodiazepine derivative was then reacted with N-methyl piperazine (125) to give 26. Scheme 5.2 The scheme 5.3 discloses an alternate process for preparing compound 26 involving the reaction of benzodiazepine derivative 128 with piperazine (129) to result N-desmethyl Olanzapine (130) which upon methylation using dimethyl sulphate afforded 26.

5 Scheme Zbigniew Majka et al., describes a process 87 (scheme 5.4) for the preparation of Olanzapine involving the use of N-desmethyl Olanzapine (130) as the starting material wherein it was reacted with ethyl formate to produce the corresponding N-formyl Olanzapine (131) which upon reduction with a group I or II metal borohydride gave Olanzapine (26). Scheme 5.4 Roman Lenarsic describes a process 88 for the preparation (Scheme 5.5) of Olanzapine starting from the reaction of benzodiazepine-2,4- diamine (132) with N-methyl piperazine to give bis (methyl piperazinyl) benzodiazepine (133). The compound 133 upon reaction with propionaldehyde in the presence of lithium diisopropylamide resulted benzodiazepine-1-propanol (134), which on further reaction with trifluoroacetic anhydride yielded the corresponding propylidene

6 179 derivative 135. The propylidene derivative upon reaction with sulfur in the presence of triethylamine gave the targeted compound 26. Scheme 5.5 Zhengyong Wang 89 describes a multi step process for the preparation of Olanzapine (scheme 5.6) by protecting the amino group of 2-(2-nitroanilino)-5-methyl thiophene-3-carbonitrile (123) with benzyl bromide to produce the protected intermediate 136. Cyclizing the protected intermediate 136 via reduced intermediate compound 137 with tin chloride to produce benzodiazepine derivative 138, which was then reacted with N-methyl piperazine to give N-protected Olanzapine (139), finally which upon deprotection provided Olanzapine.

7 Scheme Rolf Keltjens et al., describes 90 an improved process for the preparation of Olanzapine (scheme 5.7). The process comprises reaction of compound 128 or its salt with N-formyl piperazine 140 to form N- formyl Olanzapine (131). The N-formyl Olanzapine or its salt was reduced with Red-Al to form Olanzapine (26) or its salt.

8 Scheme : Summary of reported synthetic schemes As evident from the earlier reported synthetic schemes, Olanzapine was synthetically prepared mainly by two types (i) cyclizing the open chain derivative to form diazepine ring at the final stage of the synthesis; (ii) cyclizing the open chain derivative to form an intermediate compound containing diazepine moiety, which is then transformed to desmethyl Olanzapine on reaction with piperazine, followed by its conversion to Olanzapine. In another alternative disclosed methodology, Olanzapine was also prepared by N-methylation of its corresponding desmethyl derivative. In most of the above known synthetic procedures for the preparation of Olanzapine, the reduction of nitro group is a common step before the cyclization of the open chain derivative to afford diazepine moiety. Use of many different reagents for the functional group transformation may result in degradation of the product, which inturn requires tedious purification procedures and results in low yield of the final desired compound.

9 5.3: Present Work 182 The earlier processes for the preparation of Olanzapine mainly involved the reaction comprising the conversion of nitro functional group to afford amino derivative, followed by cyclization under acidic conditions to result diazepine derivative. The present research work specifically avoids the use of nitro derivative as starting materials and the use of reducing agents at any stage of the process. The present work involves a simple two step process involving Suzuki coupling mechanism 91, 92 with the aid of organo metallic reagents resulting new intermediate compounds for the preparation of Olanzapine. The resulted product was in comparison with authentic sample. We have further systematically identified, synthesized and characterized four process related compounds of Olanzapine.

10 : Results and Discussion - Retro synthetic Pathway for Olanzapine Scheme 5.8 Accordingly scheme 5.8 has been systematically designed to get Olanzapine with desired purity and appreciable yield. Scheme 5.8 described palladium catalyzed coupling of 2-amino-5-methylthiophene- 3-carbonitrile (122) with 1-bromo-2-iodobenzene (143) in the presence of palladium mediated catalyst, xantphos ligand and cesium carbonate base to give a novel intermediate compound 2-(2-bromophenylamino)-5- methylthiophene-3-carbonitrile (142). The compound 142 was further reacted with N-methyl piperazine in presence of trimethyl aluminum to afford another novel imine derivative 141, which upon subsequent cyclization to result Olanzapine (26).

11 : Synthesis of 2-(2-bromophenylamino)-5-methylthiophene-3- carbonitrile (142) Palladium-catalyzed cross-coupling reactions are among the most useful synthetic methods for the reaction of halo derivatives with an amine derivates, and the application of this property has been specifically utilized for the synthesis of novel compound 142. A suitable moles of compound 143 is coupled (scheme 5.8a) with 122 in the presence of tris (dibenzylidineacetone) dipalladium catalyst, 4,5- bis(diphenylphosphino)-9,9-dimethylxanthene as ligand and cesium carbonate as base in a mixture of 1,4-dioxane and xylene media to afford novel compound 142 with 78.0% yield and having the purity of 98.7% by HPLC analysis. Scheme 5.8a IR Spectrum (Fig.5.1) of 142 exhibited a sharp signal at about 3322 cm -1 corresponding to NH absorption and CN function absorption at 2222 cm -1. In 1 H-NMR spectrum (Fig.5.2), the down field region was characterized by the presence of five aromatic proton signals at δ 7.59 (dd, 1H, J=1.2, 8.0, Ar-H), 7.35 (dd, 2H, J=1.2, 8.0, Ar-H), 6.75 (m, 1H, Ar-H) and 6.63 (s, 1H, Ar-H). Sharp singlet signal appeared at δ 2.41(s,

12 185 3H, Ar-CH3) is attributed to aromatic methyl group. The mass spectrum (Fig.5.3) displayed a molecular ion peak at m/z 293 (M+1) along with the bromine isotopic abundance at m/z 295(M+1). Thus, all the spectral data (IR, 1 H-NMR, 13 C-NMR & Mass) was in conformity with the assigned structure of 2-(2-bromophenylamino)-5-methylthiophene-3-carbonitrile (142).

13 186

14 187

15 : Synthesis of N-(2-bromophenyl)-3-(imino(4-methylpiperazin-1- yl)methyl)-5-methylthiophen-2-amine (141) The preparation of another novel imine derivative 141 is achieved by reaction (scheme 5.8b) of compound 142 with N-methyl piperazine in presence of trimethyl aluminum and xylene as solvent. Scheme 5.8b In the IR spectrum (Fig.5.4), the two absorption peaks corresponding to amino and imino NH appeared at 3366 and 3259 cm -1 respectively. The 1 H NMR spectrum (Fig. 5.5) displayed five aromatic protons at 7.57(d, 1H, J=8.0, Ar-H), 7.24 (m, 2H, Ar-H), 6.78 (m, 1H, Ar-H) and 6.43 (s, 1H, Ar-H), piperazine protons at 3.38 (br, 8H, CH2) and two methyl groups at 2.22 (s, 6H, 2CH3). The mass spectrum (Fig.5.6) displayed a protonated molecular ion peak at m/z (M+1) with positive segment polarity.

16 189

17 190

18 191

19 : Synthesis of Olanzapine (26) Preparation of Olanzapine is finally achieved by palladiumcatalyzed cyclization of novel imine intermediate 141 in the presence of 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BiNAP) ligand and cesium carbonate base in toluene as suitable solvent (Scheme 5.8c). The resultant crude compound was subjected to column chromatography and followed by recrystallization in dichloromethane provided the desired compound as yellow colored crystalline solid with ICH grade purity. Thus resulted compound was compared with the authentic sample of Olanzapine by HPLC analysis and also confirmed by its complete spectral data. Scheme 5.8c The UV spectrum (Fig.5.7) of Olanzapine (26) recorded in methanol (conc=0.001% w/v) using Perkin-Elmer UV-VIS spectro photometer model Lambda 35. It exhibited three peaks with maxima at λ 202, 226 and 271 nm. The FT-IR spectrum (Fig.5.8) of 26 was recorded using KBr pellet. The absorption peak observed at 3236 cm -1 due to N-H stretching. The 1 H NMR spectrum (Fig.5.9) recorded in CDCl3 showed

20 193 characteristic signals at δ 7.57 (s, 1H, NH), (m, 3H, Ar-H), 6.68 (d, 1H, J=8.0, Ar-H), 6.32 (s, 1H, Ar-H), (br, 4H, CH2), 2.38 (br, 4H, CH2), 2.26 (s, 3H, CH3), 2.21 (s, 3H, CH3). The EI mass spectrum (Fig.5.10) displayed a protonated molecular ion at m/z = 313 (M+1) and the major fragment ion (scheme 5.8d) assigned as 2-methyl- N-vinyl-10H-benzo[b]thieno- [2,3-e][1,4]diazepin-4-amine (26d). Scheme 5.8d

21 194

22 195

23 : Related compounds or impurities The HPLC analysis of Olanzapine (26), showed impurity peaks ranging around 0.05 to 0.15%. To identify the molecular weight of the respective impurities, LC-MS was performed. From the molecular weight information obtained from LC-MS analysis, extensive study was undertaken to synthesize the impurities. Finally all these impurities were synthesized and subsequently subjected for spectral analysis (Mass, 1 H NMR, 13 C NMR and IR). Based on the spectral data, these impurities 93 were characterized as 2-methyl-4-(piperazin-1-yl)-10,10adihydro-3aH-benzo[b]thieno[2,3-e] [1,4]diazepine (130), 2-methyl-10Hbenzo[b]thieno[2,3-e][1,4]diazepin-4-ol (144), Olanzapine N-oxide (145)

24 and (chloromethyl)-1-methyl-4-(2-methyl-10H-benzo[b]thieno[2,3- e][1,4]diazepin-4-yl)piperazin-1-ium chloride (146) : Preparation of Related compound 130 This impurity is formed due to the presence of piperazine in N- methyl piperazine during the condensation of compound 142 with N- methyl piperazine. This impurity was prepared (Scheme 5.9) by refluxing compound 128 with piperazine (129) in dimethyl sulfoxide and toluene mixture. After completion of the reaction, mass was cooled, filtered and washed with toluene. After conventional working up procedure gave the desired compound, which is purified by recrystallization from ethyl acetate. Scheme 5.9 In the IR spectrum (Fig.5.11), the two absorption peaks corresponding to NH appeared at 3221 cm -1 and 3176 cm -1 respectively. The 1 H NMR spectrum (Fig. 5.12) displayed five aromatic protons at (m, 3H, Ar-H), 6.60 (d, 1H, Ar-H) and 6.35 (s, 1H, Ar-H). Piperazine protons appeared at (m, 4H, CH2), (m,

25 198 4H, CH2) and aromatic methyl group at 2.22 (s, 3H, CH3). The mass spectrum (Fig.5.13) displayed a molecular ion peak at m/z (M).

26 199

27 : Preparation of Related compound 144 This impurity is formed due to the presence of aqueous basic medium workup during the upstream process of Olanzapine. This impurity was prepared (scheme 5.10) by refluxing 128 with aqueous solution of sodium hydroxide. After completion of the reaction, the required product is isolated and further purified by recrystallisation with methanol and water mixture. Scheme 5.10 The IR spectrum (Fig.5.14) of 144 showed NH and carbonyl absorptions at 3281 cm -1 and 1637 cm -1 respectively. These absorption signals are week due to keto enal tautomerism. The 1 H NMR spectrum (Fig.5.15) displayed five aromatic protons at 6.87 (m, 3H, Ar-H), 6.78(d, 1H, Ar-H), 6.58 (s, 1H, Ar-H) and methyl group attached to aromatic ring appeared at 2.23 (s, 3H, CH3). The ESI-MS spectrum of (Fig.5.16) displayed a molecular ion at m/z 230 (M). This spectral data is consistent with the assigned structure of 144.

28 201

29 : Preparation of Related Compound 145 This impurity is formed due to aerial oxidation of Olanzapine during the process of its preparation and also upon storage under normal packing conditions. This impurity was prepared by the oxidation of Olanzapine (26) with m-chloroperbenzoic acid (scheme 5.11) in acetic acid. Scheme 5.11

30 203 The IR spectrum (Fig.5.17) of 145 showed NH absorption at 3223 cm -1. The 1 H NMR spectrum (Fig.5.18) characterized by presence of aromatic protons at 6.98 (m, 2H, Ar-H), 6.90 (m, 1H, Ar-H), 6.62 (d, 1H, Ar-H), 6.35 (s, 1H, Ar-H), piperazine protons appeared at 4.00 (m, 4H, CH2), 3.25 (b, 4H, CH2) and two methyl groups at 2.30 (s, 6H, 2CH3). The MS spectrum of 145 (Fig.5.19) displayed a protonated molecular ion at m/z 329 (M+1) with positive segment polarity. The 13 C NMR spectrum (Fig.5.18a) was compared with Olanzapine, wherein, N- methyl carbon appeared a downfield shift from 45 to 15.4 ppm. Also two methylene carbons attached to methyl nitrogen showed up field shift from 54 ppm to 65 ppm. Based on this spectral data, N-oxide formation on the nitrogen on which methyl group is attached in the Olanzapine moiety is rationalized.

31 204

32 : Preparation of Related Compound 146 This impurity is formed due to the reaction of Olanzapine with dichloromethane for longer period of time and this impurity was prepared (Scheme 5.12) by refluxing the Olanzapine with dichloromethane for prolonged time.

33 Scheme The IR spectrum (Fig.5.20) of 146 showed NH absorption at 3213 cm -1. The 1 H NMR spectrum (Fig.5.21) characterized by presence of five aromatic protons at 6.88 (m, 3H, Ar-H), 6.78(m, 1H, Ar-H), 6.40 (s, 1H, Ar-H) one methylene group which is attached to quaternary nitrogen is appeared at 5.65 (s, 2H, CH2), piperazine protons appeared at (m, 2H, CH2), 3.35 (br, 6H, CH2). Quaternary nitrogen methyl group appeared at 3.25 (s, 3H, CH3) and aromatic methyl group at 2.25 (s, 3H, CH3). The MS spectrum of 146 (Fig.5.22) displayed a molecular ion at m/z 361, which is less than one chlorine atom along with one chlorine isotopic abundance. This spectral data fully agreed with the assigned structure of targeted compound.

34 207

35 208

36 Conclusions Thus, we have developed a simple, new synthetic route to Olanzapine. Further to this, we have also identified, synthesized and characterized the related compounds formed during the synthesis Olanzapine. 5.6 Experimental section Preparation of compound 142: To a stirred solution of 122 (5.4 g, mol), tris (dibenzylidineacetone)dipalladium (1.5 g, mol), cesium carbonate (36.0 g, mol), Xantophos (1.0 g, mol) in

37 210 1,4-dioxane (50. 0 ml) was added a solution of 143 (10.8 g, mol) in 10.0 ml of xylene at room temperature. After complete addition, the reaction mass was heated to 90 0 C and further stirred for the reaction completion. After completion of the reaction water was added and the reaction mixture was extracted with ethyl acetate. Organic layer was separated and washed with brine solution and dried over sodium sulfate. The mixture was concentrated under reduced pressure and the resulting residue was purified by column chromatography to yield compound 142 (9.0 g, Yield: 78.9 %, HPLC purity 98.7%). IR (cm -1 ): 3322 (NH), 2222 (CN); 1 H NMR (CDCl3, ppm): 2.41(s, 3H, Ar-CH3), 6.63 (s, 1H, Ar-H), 6.75 (m, 1H, Ar-H), 7.35 (dd, 2H, J=1.6, 8.4, Ar-H), δ 7.59(dd, 1H, J=1.2, 8.0, Ar-H); 13 C NMR (200 MHz, CDCl3): δ 15.3, 96.4, 112.4, 114.7, 116.0, 122.7, 123.1, 128.6, 130.0, 133.1, 139.7, MS: m/z 293 (M+1); Analysis Calcd. for C12H9BrN2S: C, 49.16; H, 3.09; N, Found: C, 49.21; H, 3.12; N, Preparation of 141 from 142: To a clear solution of 142 (2.5 g, mol), N-methylpiperazine (1.70 gm, mol] in xylene (50.0 ml) was added trimethyl aluminium (5.5 ml, mol, 2.0M solution in toluene) at º C with stirring. The resulting solution was heated to º C and stirred for the reaction completion. After completion of the reaction, the solution was cooled to 0 º C and sodium potassium tartrate salt solution was added. The resulting mixture was extracted with ethyl acetate (3x50 ml) and washed with 3.0 N hydrochloric acid

38 211 solution (2x10 ml). The combined aqueous layer was washed with ether and basified the aqueous layer with aqueous sodium hydroxide solution (20%). The resulting mixture was extracted with ethyl acetate (3x50 ml) and the combined organic layers were washed with water, brine and dried over sodium sulfate. The mixture was concentrated under reduced pressure to yield the targeted compound 141 as brown colored solid (2.0 g, Yield: 60.0%, HPLC purity 85.0%). IR (cm -1 ): 3366 (NH), 3259 (NH); 1 H NMR (DMSO-d6, ppm): 2.22 (s, 6H, 2CH2), 3.38 (br, 8H, CH2), 6.43 (s, 1H, Ar-H), 6.78 (m, 1H, Ar-H), 7.24 (m, 2H, Ar-H), 7.57(d, 1H, J=8.0, Ar- H); 13 C NMR (200 MHz, DMSO): δ 15.5, 46.2, 46.9, 55.0, 118.7, 119.3, 123.0, 123.8, 124.0, 128.0, 141.1,144.4, 153.8, MS: m/z 393 (M+1); Analysis Calcd. for C17H21BrN4S: C, 51.91; H, 5.38; N, Found: C, 51.86; H, 5.41; N, Preparation of Olanzapine (26): The compound 141 (1.5 g, mol), cesium carbonate [1.60 g, mol], BINAP [0.3 g, mol] in toluene (10.0 ml) was added catalytic amount of tris [dibenzylidineacetone] dipalladium and stirred at room temperature for 1.0 hour. The resulting reaction was heated to 60 º C for 4.0 hours. After completion of the reaction, the solution was cooled to room temperature, water (50 ml) was added and extracted with ethyl acetate [3x25 ml] and the combined organic layers were washed with brine and dried over sodium sulfate. The mixture was concentrated under reduced pressure to afford crude compound. The crude compound was purified by column

39 212 chromatography and followed by recrystallisation from methylene chloride yielded 0.5 g of compound as light yellow colored solid (Yield: 45.0%, HPLC Purity: 99.2%). IR (cm -1 ): 3236 (NH); 1 H NMR (DMSO-d6, ppm): 2.21 (s, 3H, CH3), 2.26 (s, 3H, CH3), 2.38 (br, 4H, CH2), (br, 4H, CH2), 6.32 (s, 1H, Ar-H), 6.68 (d, 1H, J=8.0, Ar-H), (m, 3H, Ar-H), 7.57 (s, 1H, NH); 13 C NMR (200 MHz, DMSO): δ 15.0, 45.7, 46.4, 54.4, 54.4, 118.1, 118.7, 122.4, 123.1, 123.3, 127.4, 127.8, 140.5,143.8, 153.2, MS: m/z 313 (M+1); Analysis Calcd. for C17H20N4S: C, 65.35; H, 6.45; N, Found: C, 66.40; H, 6.49; N, Preparation of Related Compound (130): To a solution of 128 (20.0 g, mol) in dimethyl sulfoxide (50.0 ml) and toluene (100 ml) was added piperazine (7.30 g, mol) and refluxed for completion of the reaction. After completion of the reaction, the mass was cooled to º C, filtered and washed with toluene (20mL). Toluene layer was treated with carbon at º C followed by addition of water (100 ml). The resulting mixture was further stirred at º C for 1 2 hours. The separated solid was filtered and dried at º C to a constant weight. The resulted product was recrystallized from ethyl acetate to yield compound 130 (Yield: 9.0 g; HPLC purity: 99.4%). IR (cm -1 ): 3221 (NH), 3176 (NH); 1 H NMR (CDCl3, ppm): 2.22 (s, 3H, CH3), (m, 4H, CH2), (m, 4H, CH2), 6.35 (s, 1H, Ar-H), 6.60 (d, 1H, Ar-H), (m, 3H, Ar-H); MS: m/z 298 (M); Analysis Calcd. for

40 213 C16H18N4OS: C, 64.40; H, 6.08; N, Found: C, 64.45; H, 6.13; N, Preparation of Related Compound (144): A mixture of 128 (5.0 g, mol) and 30% aqueous sodium hydroxide (20 ml) were heated to reflux till reaction was complete. The reaction mixture was cooled to room temperature and the resulting solid was filtered and washed with water (50 ml). The resultant wet cake was dissolved in methanol (100 ml) at reflux, treated with carbon (1.0) and finally water (50 ml) was added for precipitating the solid. The isolated solid was filtered, washed with water (10 ml) and dried at 70 C to yield compound 144 (Yield: 3.5 g; HPLC Purity: >99 %). IR (cm -1 ): 3281 (OH), 1637 (CO); 1 H NMR (DMSO-d6, ppm): 2.23 (s, 3H, CH3), 6.58 (s, 1H, Ar-H), 6.78(d, 1H, Ar- H), 6.87 (m, 3H, Ar-H), 8.80 (s, 1H, NH), 9.07 (s, 1H, NH); MS: m/z 230 (M); Analysis Calcd. for C12H10N2OS: C, 62.59; H, 4.38; N, Found: C, 62.66; H, 4.42; N, Preparation of Related Compound (145): To a mixture of 26 (12.5 g, mol) in acetic acid (62.5 ml), m-chloroperbenzoic acid (7.0 g, 0.04 mol) was added and the mixture stirred at 50 C for reaction completion. The reaction mass was concentrated under reduced pressure and the residual mass was dissolved in dichloromethane (50 ml). The resultant solution was washed with water, concentrated under reduced pressure and finally purified by column chromatography to yield compound 145 (Yield: 8 g, HPLC purity: 94%). IR (cm -1 ): 3223 (NH); 1 H NMR (CDCl3,

41 214 ppm): 2.30 (s, 6H, 2CH2), 3.25 (br, 4H, CH2), 4.00 (m, 4H, CH2), 6.35 (s, 1H, Ar-H), 6.62 (d, 1H, Ar-H), 6.90(m, 1H, Ar-H), 6.98 (m, 2H, Ar-H); 13 C NMR (200 MHz, CDCl3, ppm): 15.4, 41.6, 60.4, 65.1, 118.3, 119.3, 122.4, 124.4, 124.5, 128.0, 129.9, 140.5, 142.9, 153.3, MS: m/z 329 (M+1); Analysis Calcd. for C17H20N4OS: C, 62.17; H, 6.14; N, Found: C, 62.09; H, 6.02; N, Preparation of Related Compound (146): The compound 26, 12.5 g, mol) in dichloromethane (125 ml) was stirred at reflux for 1-2 days to complete the reaction. The reaction mass was concentrated to a minimum volume and stirred at 10 C to separate the solid. The isolated solid was filtered off, washed with dichloromethane (65.0 ml) and dried at 35 C to a constant weight. The solid was stirred in hot methanol (10.0 ml) at 65 C, filtered, washed with methanol (3.0 ml) and dried at 35 C to yield 146 (Yield: 10.5 g, HPLC purity: 97%). IR (cm -1 ): 3213 (NH); 1 H NMR (DMSO-d6, ppm): 2.25 (s, 3H, CH3), 3.25 (s, 3H, CH3), 3.35 (br, 6H, CH2), (m, 2H, CH2), 5.65 (s, 2H, CH2), 6.40 (s, 1H, Ar-H), 6.78 (m, 1H, Ar-H), 6.88 (m, 3H, Ar-H; MS: m/z 361 (M 35.5); Analysis Calcd. for C18H24Cl2N4S: C, 54.13; H, 6.06; N, Found: C, 54.17; H, 6.12; N,