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CHITHRALEKHA DEVI AND RAJASEKHARAN
dino-3-arylthiourea or 1-alkyl-3-(N-nitroamidino)thiourea (1 mmol) in
DMF (5 ml) and the reaction mixture was briefly warmed. To the warm
solution, triethylamine (1.1 mmol) was added and the solution was kept at
80–85ꢀC for 15 min. It was then cooled and added to cold water with con-
stant stirring. The yellow precipitate formed was filtered, washed with water
and dried. The crude material was purified by crystallization. The details of
the thiazoles thus prepared are: 4-Amino-2-(4-chlorophenylamino)-5-( fur-
2-oyl )-thiazole 4a: crystallized from benzene-petroleum ether, yield 62%,
m.p. 227–230ꢀC. Analysis: Found: C, 52.8; H, 3.0; N, 13.0%: Calc. for
C14H10ClN3O2S (319.8): C, 52.6; H, 3.2; N, 13.1%. IR (KBr) cmꢁ1: 3181,
1
1599, 1547, 1484, 1439, 1228, 1095, 1022, 828, 744. H NMR: (300 MHz,
DMSO-d6) d: 6.71 (m, H-4), 7.13 (d, J 2Hz, H-3), 7.45 (d, 2H, J 8.3 Hz,
2ArH), 7.73 (d, 2H, J 8.3 Hz, 2ArH), 7.95 (d, J 1.6 Hz, H-5), 8.43 (broad,
NH2), 10.98 (s, NH). EIMS: m/z (%): 321 (M þ 2, 39), 319 (Mþ, 100), 318
(34), 224 (8), 153 (23), 140 (30), 126 (12), 111 (13), 95 (54), 67 (13). 4-Amino-
5-( fur-2-oyl )-2-phenylaminothiazole 4b: crystallized from benzene–
petroleum ether, yield 54%, m.p. 170–172ꢀC. Analysis: Found: C, 58.9;
H, 3.7; N, 14.9%: Calc. for C14H11N3O2S (285.3): C, 58.9; H, 3.9; N,
14.7%. IR (KBr) cmꢁ1: 3444, 3272, 3018, 1627, 1594, 1574, 1528, 1497,
1481, 1438, 1254, 1223, 1187, 1106, 1018, 885, 752, 690, 649. EIMS: m/z
(%): 285 (Mþ, 100), 284 (21), 218 (6), 190 (3), 140 (19), 119 (35), 95 (33), 92
(10), 77 (16), 67 (5). 4-Amino-5-( fur-2-oyl )-2-(4-methoxyphenylamino)thia-
zole 4c: crystallized from benzene–petroleum ether, yield 50%, m.p.
212–215ꢀC. Analysis: Found: C, 57.3; H, 4.3; N, 13.2%: Calc. for
C15H13N3O3S (315.4): C, 57.1; H, 4.2; N, 13.3%. IR (KBr) cmꢁ1: 3143,
1597, 1568, 1545, 1514, 1483, 1441, 1246, 1175, 1090, 1017, 886, 830, 751.
1H NMR: (300 MHz, DMSO-d6) d: 3.84 (s, OCH3), 6.50–6.53 (m, H-4), 6.95
(d, J 5.8 Hz, 2ArH), 7.15 (d, J 2Hz, H-3), 7.36 (d, J 5.8 Hz, 2ArH), 7.52(d,
J 1.6 Hz, H-5), 8.33 (broad, NH2), 10.85 (s, NH). EIMS: m/z (%): 315 (Mþ,
100), 314 (16), 285 (71), 284 (18), 219 (21), 207 (16), 165 (8), 150 (10), 149
(30), 140 (36), 122 (35), 107 (16), 95 (67), 67 (19). 4-Amino-2-(4-chloro-
phenylamino)-5-(thien-2-oyl )thiazole 4d: crystallized from benzene, 65%,
m.p. 230–232ꢀC. Analysis: Found: C, 50.0; H, 3.1; N, 12.6%: Calc. for
C14H10ClN3OS2 (335.8): C, 50.1; H, 3.0; N, 12.5%. IR (KBr) cmꢁ1: 3400,
3273, 2284, 1605, 1552, 1492, 1235, 1090, 1058, 1011, 820, 751, 686, 653.
1H NMR: (300 MHz, DMSO-d6) d: 7.1 (m, H-4), 7.42(d, J 8.8 Hz, 2ArH),
7.59 (d, J 3.6 Hz, H-3), 7.69 (d, J 8.8 Hz, 2ArH), 7.81 (d, J 4.8 Hz, H-5), 8.29
(broad, NH2), 11.0 (s, NH). EIMS: m/z (%): 337 (M þ 2, 21), 335 (Mþ, 74),
334 (58), 252 (4), 224 (4), 223 (8), 169 (4), 156 (25), 155 (11), 153 (23), 152
(6), 126 (12), 111 (100), 83 (18). 4-Amino-2-phenylamino-5-(thien-2-oyl )thia-
zole 4e: crystallized from benzene, yield 62%, m.p. 149–150ꢀC. Analysis:
Found: C, 55.9; H, 3.8; N, 14.1%: Calc. for C14H11N3OS2 (301.4): C, 55.