Molecules 2010, 15
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3.18.2. Method-B
A mixture of 1a,d (20 mmol) and phenyl (or p-clorophenyl) isothiocyanate (20 mmol) placed in a
50 mL conical flask covered with a funnel glass and then irradiated with microwaves (950 W) for
35–40 seconds. The cold reaction mixture was then treated with ethanol and the solid product was
filtered off and recrystallized from ethanol [13].
2-(3-Phenylthioureido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic acid ethyl ester (20). Fine
colorless needles, m.p. 187–189 ºC; yield: (78%)A, (89%)B; IR (cm–1): 3,196 (NH), 3,032 (Ar-CH),
1
1,656 (CO), 1,554 (C=C), 1,195 (C=S); H-NMR (CDCl3) δ: 0.97 (3H, J = 7.3 Hz, t, CH2CH3), 1.43
(4H, m, 2CH2), 2.27 (2H, m, CH2), 2.41 (2H, m, CH2), 3.87 (2H, J = 7.3 Hz, q, CH2-CH3), 6.89 (t,
J = 7.32 Hz, Ar-CH(p)), 7.05 (2H, t, J = 7.32 Hz, Ar-CH(m)), 7.11 (2H, d, J = 8.08 Hz, Ar-CH(o)),
10.03 (s, NH), 11.70 (s, NH); 13C-NMR (CDCl3) δ: 14.25 (CH3), 22.92, 23.02, 24,09, 26.17 (aliphatic
carbons); 60.14 (O-CH2), 112.01, 125.89, 130.35, 150.17 (4C, thiophene carbons); 124.51,
125.89(2C), 128.94 (2C), 137.81 (aromatic carbons), 166.13 (C=O); 175.99 (C=S); MS: m/z : 360 (M+,
20%), 326 (M+-SH, H, 17%), 225 (M+- (SH, H, C6H5, CN) + 2H, 33%).
2-(3-(4-Chlorophenyl)thioureido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic acid ethyl ester
(21). Yellow needles, m.p. 198–199 ºC; yield (71%)A, (88%)B; IR (cm–1): 3,141 (NH), 3,078 (Ar-CH),
1
1,652 (CO), 1,558 (C=C), 1,195 (C=S); H-NMR (CDCl3) δ: 1.25 (3H, t, CH2CH3), 1.75 (4H, m,
2CH2), 2.60 (2H, m, CH2), 2.70 (2H, m, CH2), 4.15 (2H, q, CH2CH3), 7.28 (2H, d, J = 8.8 Hz, Ar-CH),
7.41 (2, d, J = 8.8 Hz, Ar-CH), 7.92 (br. s, NH), 12.25 (1H, s, NH); 13C-NMR (CDCl3) δ: 14.12 (CH3),
22.92, 23.02, 24.40, 26.38 (4C, aliphatic carbons), 60.65 (O-CH2), 113.23, 127.28, 133.18, 149.81
(thiophene carbons), 126.80 (2C), 130.13 (2C), 130.96, 134.66 (phenyl carbons), 166.68 (C=O),
176.06 (C=S); MS: m/z 394 (M+, 26%) 396 (M++2, 15%), 225 (M+-(OCH2CH3,NH-C6H4Cl) + 2H,
39%), 179 (M+-(OCH2CH3,NHCSNH-C6H4Cl), 100%).
6-Benzyl-2-(3-phenylthioureido)-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylic acid ethyl ester
(22). Orange needles, m.p. 274–276 ºC; yield (64%)A,(77%)B; IR (cm–1): 3,196 (br, NH), 3,032 (Ar-
CH), 1,656 (CO), 1,554 (C=C), 1,197 (C=S); 1H-NMR (CDCl3) δ: 1.21 (3H, J = 7.3 Hz, t, CH2CH3),
2.93 (4H, m, 2CH2), 3.37 (4H, br. s, 2CH2), 4.12 (2H, J = 7.3 Hz, q, CH2CH3), 7.32 (5H, m, C6H5),
7.46 (5H, m, C6H5), 7.95 (s, NH), 12.11 (s, NH); MS: m/z 450 (M+-H, 16%), 91 ((Ph-CH2), 100%).
6-Benzyl-2-(3-(4-chlorophenyl)thioureido)-4,5,6,7-tetrahydro thieno [2,3-c]pyridine-3-carboxylic acid
ethyl ester (23). Yellow needles, m.p. 259–261 ºC; yield (54%)A, (69%)B; IR (cm–1): 3,176 (NH),
1
3,053, 3,031 (Ar-CH), 1,652 (CO), 1,558 (C=C), 1,197 (C=S); H-NMR (CDCl3) δ: 1.24 (3H, t,
J = 7.36 Hz, CH2CH3), 2.85 (4H, m, 2CH2), 3.57 (2H, s, CH2), 3.74 (2H, s, CH2), 4.17 (2H, q,
J = 7.36 Hz, CH2CH3), 7.22 (2H, d, J = 8.8 Hz, Ar-CH), 7.38 (2H, d, J = 8.8 Hz, Ar-CH), 7.24–7.39
(5H, m, C6H5), 8.37 (br. s, NH), 12.15 (s, NH); 13C-NMR (CDCl3) δ: 14.25 (CH3), 26.46, 50.13, 51.02,
61.85 (4C, CH2); 60.77 (O-CH2), 112.56, 127.12, 133.19, 150.65 (4C, thiophene ring); 123.90, 126.85
(2C), 130.09 (2C), 134.62 (C6H5), 126.87 (2C), 128.52 (2C), 129.17, 129.41 (p-Cl-C6H4), 166.35
(C=O), 176.03 (C=S); MS: m/z 485 (M+, 0.02%), 316 (M+-(NH-C6H4Cl,OCH2CH3) +H, 9%), 168
(M+- (NH-C6H4Cl,OCH2CH3, CH2C6H5, NCH2,CO), 80%).