Molecules 2017, 22, 461
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4.2.2. General Procedure for the Synthesis of Compounds 4a–l
The appropriate aminopyrrolopyridine 3a–l (0.01 mol) was heated in formic acid (20 mL, 85%) under
reflux for 3 h, cooled, poured onto ice water to give a precipitate, filtered off, dried, and crystallized from
ethanol to yield compounds 4a–l.
5,9-Diphenyl-7-(4-methylphenyl)-3H-pyrrolo[2,3-b]pyrido[4,3-d]pyrimidin-4-one (4a). Yield: 82%; m.p.:
◦
226–228 C; IR (KBr)
υ
(cm−1): 3412 (NH), 1726 (C=O), 1596 (C=N); MS (EI) m/z: 428 (M+, 44%);
1H-NMR (DMSO-d6)
δ (ppm): 2.34 (s, 3H, CH3), 6.8–7.9 (m, 15H, Ar-H), 8.1 (s, 1H, C-2 H), 8.3 (s, 1H,
NH, D2O exchangeable); Anal. Calcd. for C28H20N4O (428.48): C, 78.50; H, 4.67; N, 13.08%. Found: C,
78.82; H, 4.41; N, 13.23%.
5,9-Diphenyl-7-(4-methoxyphenyl)-3H-pyrrolo[2,3-b]pyrido[4,3-d]pyrimidin-4-one (4b). Yield: 87%; m.p.:
◦
214–216 C; IR (KBr)
υ
(cm−1): 3510 (NH), 1719 (C=O), 1609 (C=N), 1234 (C-O); MS (EI) m/z: 444 (M+,
19.5%); 1H-NMR (DMSO-d6)
δ
(ppm): 3.5 (s, 3H, OCH3), 6.9–7.9 (m, 15H, Ar-H), 8.12 (s, 1H, C-2 H),
8.3 (s, 1H, NH, D2O exchangeable); Anal. Calcd. for C28H20N4O2 (444.48): C, 75.68; H, 4.50; N, 12.61%.
Found: C, 75.87; H, 4.84; N, 12.33%.
5,9-Diphenyl-7-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-3H-pyrrolo[2,3-b]pyrido[4,3-d]
pyrimidin-4-one (4c). Yield: 68%; m.p.: 219–221 ◦C; IR (KBr)
υ
(cm−1): 3451 (NH), 1706, 1724 (C=O),
1617 (C=N); MS (EI) m/z: 524 (M+, 35%); 1H-NMR (DMSO-d6)
δ (ppm): 2.6 (s, 3H, CH3), 3.5 (s, 3H,
NCH3), 6.9–7.8 (m, 16H, Ar-H), 8.2 (s, 1H, C-2 H), 8.5 (s, 1H, NH, D2O exchangeable); Anal. Calcd. for
C32H24N6O2 (524.57): C, 73.28; H, 4.58; N, 16.03%. Found: C, 73.57; H, 4.24; N, 15.75%.
5,8,9-Triphenyl-7-(3,4-dichlorophenyl)-3H-pyrrolo[2,3-b]pyrido[4,3-d]pyrimidin-4-one (4d). Yield: 58%; m.p.:
◦
177–179 C; IR (KBr)
υ
(cm−1): 3379 (NH), 1707 (C=O), 1600 (C=N); MS (EI) m/z: 558 (M+, 43.5%;
M + 2, 9.2%, M + 4, 3.1%); 1H-NMR (DMSO-d6)
δ
(ppm): 6.8–8.0 (m, 18H, Ar-H), 8.25 (s, 1H, C-2 H),
8.46 (s, 1H, NH, D2O exchangeable); Anal. Calcd. for C33H20Cl2N4O (559.44): C, 70.97; H, 3.58; Cl,
12.54; N, 10.04%. Found: C, 70.67; H, 3.76; Cl, 12.41; N, 9.79%.
5,8,9-Trip◦henyl-7-(4-methoxyphenyl)-3H-pyrrolo[2,3-b]pyrido[4,3-d]pyrimidin-4-one (4e). Yield: 76%; m.p.:
245–247 C; IR (KBr)
υ
(cm−1): 3406 (NH), 1699 (C=O), 1586 (C=N), 1263 (C-O); MS (EI) m/z: 520
(M+, 72.3%); 1H-NMR (DMSO-d6)
δ (ppm): 3.64 (s, 3H, OCH3), 6.9–8.0 (m, 19H, Ar-H), 8.19 (s, 1H, C-2
H), 8.3 (s, 1H, NH, D2O exchangeable); Anal. Calcd. for C34H24N4O2 (520.58): C, 78.46; H, 4.62; N,
10.77%. Found: C, 78.71; H, 4.35; N, 10.53%.
5,8,9-Triphenyl-7-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-3H-pyrrolo[2,3-b]pyrido[4,3-d]
pyrimidin-4-one (4f). Yield: 61%; m.p.: 195–197 ◦C; IR (KBr)
υ
(cm−1): 3447 (NH), 1682, 1714 (C=O),
1603 (C=N); MS (EI) m/z: 600 (M+, 83.6%); 1H-NMR (DMSO-d6)
δ (ppm): 2.71 (s, 3H, CH3), 3.7 (s, 3H,
NCH3), 6.7–7.9 (m, 20H, Ar-H), 8.18 (s, 1H, C-2 H), 8.45 (s, 1H, NH, D2O exchangeable); Anal. Calcd.
for C38H28N6O2 (600.67): C, 76.00; H, 4.67; N, 14.00%. Found: C, 75.72; H, 4.92; N, 13.85%.
5-(4-Methoxyphenyl)-9-phenyl-7-(4-methylphenyl)-3H-pyrrolo[2,3-b]pyrido[4,3-d]pyrimidin-4-one (4g). Yield:
◦
73%; m.p.: 228–230 C; IR (KBr)
υ
(cm−1): 3340 (NH), 1691 (C=O), 1617 (C=N), 1229 (C-O); MS (EI) m/z:
458 (M+, 16%); 1H-NMR (DMSO-d6)
δ
(ppm): 2.5 (s, 3H, CH3), 3.67 (s, 3H, OCH3), 6.8–7.9 (m, 14H,
Ar-H), 8.1 (s, 1H, C-2 H), 8.34 (s, 1H, NH, D2O exchangeable); Anal. Calcd for C29H22N4O2 (458.51): C,
75.98; H, 4.80; N, 12.22%. Found: C, 75.76; H, 4.93; N, 11.85%.
5,7-Di(4-methoxyphenyl)-9-phenyl-3H-pyrrolo[2,3-b]pyrido[4,3-d]pyrimidin-4-one (4h). Yield: 78%; m.p.:
◦
223–225 C; IR (KBr)
υ
(cm−1): 3374 (NH), 1703 (C=O), 1602 (C=N), 1225 (C-O); MS (EI) m/z: 474 (M+,
43.6%); 1H NMR (DMSO-d6)
δ
(ppm): 3.45 (s, 3H, OCH3), 3.6 (s, 3H, OCH3), 6.8–7.8 (m, 14H, Ar-H),
8.13 (s, 1H, C-2 H), 8.4 (s, 1H, NH, D2O exchangeable); Anal. Calcd for C29H22N4O3 (474.51): C, 73.42;
H, 4.64; N, 11.81%. Found: C, 73.63; H, 4.91; N, 11.59%.
5-(4-Methoxyphenyl)-9-phenyl-7-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-3H-pyrrolo[2,3-b]
pyrido[4,3-d]pyrimidin-4-one (4i). Yield: 57%; m.p.: 227–229 ◦C; IR (KBr)
υ
(cm−1): 3336 (NH), 1706,