Molecules 2008, 13
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formed were collected by filtration, washed with cold water, and recyrstallized from EtOH or 1:1
EtOH/DMF to afford 6a-d and 8a, b respectively.
5-(4-Bromophenyl)-3-imino-6-mercapto-2-phenyl-2,3-dihydropyridazine-4-carbonitrile (6a): Brown
crystals (70%), mp. 233-235oC; IR (cm-1): 3404, 3318 (NH), 2206 (CN); 1H-NMR δ: 6.09 (s, 1H, SH),
7.14-7.42 (m, 2H, Ar-H), 7.52-7.60 (m, 3H, Ar-H), 7.75 (d, 2H, J = 8 Hz, Ar-H), 8.17 (d, 2H, J = 8 Hz,
Ar-H), 8.33 (s, 1H, NH); MS: 383 (M+,79Br, 19%); 385 (M++2, 81Br, 18%); Anal. Calcd. for
C17H11BrN4S (383.27): C, 53.27; H, 2.89; N, 14.62. Found: C, 53.33; H, 2.73; N, 14.53.
5-(4-Bromophenyl)-2-(4-chlorophenyl)-3-imino-6-mercapto-2,3-dihydropyridazine-4-carbonitrile (6b):
1
Brown crystals (64%), mp. 263-265oC; IR (cm-1): 3400, 3322 (NH), 2209 (CN); H-NMR δ: 6.45 (s,
1H, SH), 7.54 (d, 2H, J = 8 Hz, Ar-H), 7.67 (d, 2H, J = 8 Hz, Ar-H), 7.89-8.10 (m, 4H, Ar-H), 8.29 (s,
1H, NH); Anal. Calcd. for C17H10BrClN4S (417.71): C, 48.88; H, 2.41; N, 13.41. Found: C, 48.69; H,
2.54; N, 13.77.
5-(4-Bromophenyl)-3-imino-6-mercapto-2-p-tolyl-2,3-dihydropyridazine-4-carbonitrile (6c): Brown
1
crystals (64%), mp. 245-247oC; IR (cm-1): 3390, 3332 (NH), 2212 (CN); H-NMR δ: 2.34 (s, 3H,
CH3), 5.87 (s, 1H, SH), 7.24 (d, 2H, J = 9 Hz, Ar-H), 7.44 (d, 2H, J = 9 Hz, Ar-H), 7.61 (d, 2H, J = 9
Hz, Ar-H), 8.26 (d, 2H, J = 9 Hz, Ar-H), 8.39 (s, 1H, NH); Anal. Calcd. for C18H13BrN4S (397.29): C,
54.42; H, 3.30; N, 14.10. Found: C, 54.75; H, 3.56; N, 14.34.
5-(4-bromophenyl)-3-imino-6-mercapto-2-(4-methoxyphenyl)-2,3dihydropyridazine-4-carbonitrile
(6d): Brown crystals (69%), mp. 249-251oC; IR (cm-1): 3395, 3320 (NH), 2208 (CN); 1H-NMR δ: 3.65
(s, 3H, OCH3), 6.80 (s, 1H, SH), 7.26-7.87 (m, 8H, Ar-H), 8.27 (s, 1H, NH); 13C-NMR δ: 55.48
(OCH3), 89.81 (C-4), 112.43 (CN), 114.83 (C-3´5´), 115.93 (C-4´´), 118.59 (C-2´, 6´), 126.20 (C-
2´´,6´´), 129.84 (C-3´´,5´´), 132.08 (C-1´´), 141.88 (C-1´), 148.97 (C-6), 155.42 (C-4´), 159.76 (C-5),
161.46 (C-3); Anal. Calcd. for C18H13BrN4OS (413.29): C, 52.31; H, 3.17; N, 13.56. Found: C, 52.45;
H, 3.28; N, 13.84.
3-(4-Bromophenyl)-6-imino-2-mercapto-6H-pyridazino[1,6-a]quinazoline-4-carbonitrile (8a): Dark
1
brown solid (59%), mp. 314-316oC; IR (cm-1): 3435 (NH), 2224 (CN); H-NMR δ: 6.88 (s, 1H, SH),
7.20 (d, 1H, J = 8 Hz, Ar-H10), 7.55-7.58 (m, 1H, Ar-H8), 7.68 (d, 1H, J = 8 Hz, Ar-H7), 7.77 (d, 2H,
J = 9 Hz, Ar-H, 2´, 6´), 7.96-7.99 (m, 1H, Ar-H9), 8.24 (d, 2H, J = 9 Hz, Ar-H, 3´, 5´), 8.31 (s, 1H,
NH); 13C-NMR δ: 105.46 (C-4), 116.20 (CN), 121.06 (C-10), 122.08 (C-6a), 125.53 (C-4´), 126.50 (C-
7), 126.58 (C-2´, 6´), 128.97 (C-8), 129.98 (C-3´, 5´), 135.64 (C-9), 140.90 (C-1´), 141.22 (C-10a),
150.97 (C-2), 155.80 (C-3), 156.42 (C-4a), 161.95 (C-6); Anal. Calcd. for C18H10BrN5S (408.27): C,
52.95; H, 2.47; N, 17.15. Found: C, 52.79; H, 2.69; N, 17.34.
3-(4-Bromophenyl)-2-mercapto-6-oxo-6H-pyridazino[1,6-a]quinazoline-4-carbonitrile (8b): Violet
1
crystals (77%), mp. 277-279oC; IR (cm-1): 2214 (CN), 1674 (C=O); H-NMR δ: 6.80 (s, 1H, SH),
7.61-7.66 (m, 1H, Ar-H10), 7.81-7.87 (m, 1H, Ar-H8), 7.91-7.99 (m, 1H, Ar-H9), 8.09 (d, 2H, J = 8