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D2O-exchangeable NH); C NMR (DMSO-d6): δ 14.60, 61.12, 102.53,102.78, 116.38, 120.78, 120.82,
127.79, 128.35, 128.45, 130.57, 133.33, 147.90, 152.36, 163.81; MS m/z (%) 325 (2.3), 323 (73.7), 322
(M+, 100.0), 321 (6.2), 295 (12.0). Anal. Calcd for C17H14O3N4: C, 63.35; H, 4.38; N, 17.38. Found: C,
63.40; H, 4.36; N, 17.35%.
Diethyl 7-amino-1,2-dihydro-1-oxo-3-phenylpyrrolo[1,2-c]pyrimidine-4,6-carboxylate (11b). Yield
(61%), mp 225-226 oC (EtOH/ DMF); IR (KBr) ν 3445 (NH), 3320-3280 (NH) and NH2, 1720 (C=O),
1715 (C=O), 1675 (C=O cm-1; 1H NMR (DMSO- d6) δ 0.83 (t, 3H, CH3, J = 6.9 Hz), 1.27 (t, 3H, CH3, J
= 6.9 Hz), 3.93 (q, 2H, CH2, J = 6.9 Hz), 4.19 (q, 2H, CH2, J = 6.9 Hz), 6.43 (s, 1H, CH), 6.84 (s, 2H,
D2O-exchangeable NH2), 7.34-7.44 (m, 5H, ArH), 10.92 (s, 1H, D2O-exchangeable NH); 13C NMR
(DMSO-d6): δ 13.29, 14.46, 58.97, 60.33, 94.20, 101.67, 103.33, 120.02, 127.96, 128.47, 129.04, 133.55,
137.51, 144.85, 148.32, 164.19, 164.59; MS m/z (%) 371 (4.3), 370 (21.3), 369 (M+, 100), 323 (62.1),
297 (1.5), 266 (73.2), 104 (17.6). Anal. Calcd for C19H19O5N3: C, 61.78; H, 5.18; N, 11.38. Found: C,
61.76; H, 5.15; N, 11.41%.
Ethyl 3-hydrazono-5,6-dihydro-5-oxo-7-phenyl-3H-thiazolo[3,4-c]pyrimidine-8-carboxylate (14).
To a solution of 4 (0.337 g, 1 mmol) in EtOH (20 mL), and thiosemicarbazide (0.92 g, 1 mmol) was
added and the reaction mixture was refluxed for 4 h, and then allowed to cool. The solid product was
collected by filtration, washed with EtOH and crystallized from DMF/EtOH to afford 14 in 63% yield,
o
1
mp 285-287 C (DMF); IR (KBr) ν 3380 (NH), 3225-3195 (NH2), 1735 (C=O), 1675 (C=O) cm-1; H
NMR (DMSO- d6) δ 0.90 (t, 3H, CH3, J = 7.2 Hz), 4.03 (q, 2H, CH2, J = 7.2 Hz), 7.49-7.53 (m, 5H, ArH),
8.12 (s, 1H, CH), 8.66 (s, 1H, D2O-exchangeable NH), 12.05 (s, 2H, D2O-exchangeable NH2); 13C NMR
(DMSO-d6): δ 13.27, 61.58, 109.45, 120.87, 127.42, 128.28, 129.61, 130.36, 138.08, 154.63, 165.01,
172.40, 179.14. Anal. Calcd for C15H14O3N4S: C, 54.53; H, 4.27; N, 16.96. Found: C, 54.56; H, 4.32; N,
16.87%.
Reaction of 4 with hydrazine derivatives.
General procedure:
To a solution of 4 (0.674 g, 2 mmol) in EtOH (20 mL), and hydrazine hydrate (80%, 0.2 mL, 2 mmol) or
with phenylhydrazine (0.216 g, 2 mmol) was added and the reaction mixture was refluxed for 4 h, and
then allowed to cool. The formed solid product was collected by filtration, washed with EtOH and
crystallised from EtOH/DMF to afford compounds 15a and 15b, respectively.
Ethyl 6-hydrazinomethyl-2-oxo-4-phenyl-1,2-dihydropyrimidine-5-carboxylate (15a). Yield (71%), mp
o
235-236 C (EtOH/DMF); IR (KBr) ν 3320 (NH), 3275 (NH), 3100 (NH2), 1725 (C=O), 1655 (C=O)
cm-1; 1H NMR (DMSO- d6) δ 0.85 (t, 3H, CH3, J = 6.9 Hz), 3.8 (q, 2H, CH2, J = 6.9 Hz), 4.07 (s, 2H,
CH2), 7.19-7.45 (m, 5H, PhH), 8.78 (s, 2H, D2O-exchangeable NH2), 10.87 (s, 1H, D2O-exchangeable
NH), 11.72 (s, 1H, D2O-exchangeable NH); MS m/z (%) 288 (M+, 18.1), 272 (100.0), 244 (11.0), 180