Molecules 2008, 13
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ethanol. The solid was collected using suction filtration and recrystallized from a suitable solvent. The
purity of the compounds was checked using TLC.
The following compounds were prepared applying this procedure:
8-Ethoxycarbonyl-7-methyl-6-(4-chlorophenylazo)pyrrolo[1,2-a]pyridine (8). Yield: 70%, orange
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solid, m.p. = 128 °C; H-NMR (DMSO-d6) δ: 1.34 (t, J=7.0 Hz, 3H, CH3), 2.74 (s, 3H, CH3), 4.3 (q,
J=7.0 2H, OCH2), 9.9-7.21 (m, 8H, ArC-H); 13C-NMR (DMSO-d6) δ: 12.28 (CH3), 14.84 (CH3),
60.11 (OCH2), 116.73, 116.90, 119.09, 123.25, 129.59, 129.72 (6ArCH), 106.47, 128.42, 129.64,
133.48, 137.87, 152.58 (6ArC), 164.29 (C=O).
Methyl 2-(4-chlorophenylhydrazono)-3-(pyridine-2-yl)-3-ethoxycarbonylpropanoate (9). Yield: 63%,
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yellow solid, m.p. = 138-139 °C; H-NMR (DMSO-d6) δ 1.04 (t, J=7.0 Hz, 3H, CH3), 3.76 (s, 3H,
OCH3), 3.86 (q, J=7.0 Hz, 2H, OCH2), 8.16-6.11 (m, 8H, ArC-H), 10.8 (s, 1H, NH); 13C-NMR
(DMSO-d6) δ 15.05 (CH3), 53.22 (OCH3), 57.93 (OCH2), 76.64 (CH), 107.88, 116.78, 120.73, 129.64,
134.55, 136.99 (6ArCH), 123.53, 127.00, 142.40, 151.53, (C=N, 3ArC), 161.45 (C=O), 167.52(C=O).
4-Acetyl-2-(4-chlorophenyl)pyrimido[2,1-d]1,2,3,5-tetrazine (11). Yield: 63%, brown solid, m.p. =
191 °C; 1H-NMR (DMSO-d6) δ 2.51 (s, 3H, CH3), 5.51(t, J=11.0 Hz, 1H, ArCH), 7.55 (d, J =9.0 Hz,
2H, ArCH), 7.93 (d, J=9.0 Hz, 2H, ArCH), 7.61 (d, J=11.0 Hz, 1H, ArCH), 8.67 (d, J=11.0 Hz, 1H,
ArCH); 13C-NMR (DMSO-d6) δ 27.29 (CH3), 132.00, 136.82, 157.62, 161.44, (4ArC), 101.50, 124.95,
129.38, 160.91, 169.39 (5ArCH), 191.66 (C=O); MS: m/z: 287/289 (35, M+), 271/273 (100), 151/153
(37), 94 (72).
Methyl 2-(4-chlorophenyl)-2-(2-aminobenzimidazol-1-yl)ethanoate (16). Yield: 81%, white solid, m.p.
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= 198 °C; H-NMR (DMSO-d6) δ 3.70 (s, 3H, OCH3), 6.52 (s, 2H, NH2), 6.65 (d, J=7.0 Hz ,1H,
ArCH), 6.79 (t, J=8.0 Hz, 1H, ArCH), 6.97 (t, J=8.0 Hz, 1H, ArCH), 7.16 (d, J=7.0 Hz, 1H, ArCH),
7.33 (s, 4H, 4-ClC6H4); 13C-NMR (DMSO-d6) δ 52.80 (OCH3), 108.08, 115.52, 116.72, 119.13,
121.96, 129.47 (6ArCH), 119.85, 126.51, 133.89, 142.60, 144.55, 155.00 (C=N + 5ArC), 161.75
(C=O).
Methyl 2-(4-chlorophenyl)-2-(2-cyanomethylbenzimidazol-1-yl)ethanoate (17). Yield: 77%, pale
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yellow solid, m.p. = 206 °C; H-NMR (DMSO-d6) δ 3.74 (s, 3H, OCH3), 4.25 (2d(AB system), 2H,
CH2), 7.12 (d, J=7.0 Hz ,1H, ArCH), 7.37-7.23 (m, 6H, ArCH), 7.74 (d, J =7.0 Hz, 1H, ArCH), 10.97
(s, 1H, NH), 13C-NMR (DMSO-d6) δ 18.27 (CH2), 53.20 (OCH3), 110.74, 117.05, 119.97, 123.45,
124.30, 29.55 (6ArCH), 115.99, 118.21, 127.22, 135.03, 142.23, 142.96, 146.18 (C=N, C≡N, 5ArC),
161.64 (C=O).
Acknowledgements
One of the authors, Prof, Adel Awadallah, is thankful to the Ministry of Education and Higher
Education of Palestine for financial support, and to Dina El-Ashi and Mona El-Assar for their
experimental work.