Molecules 2003, 8
749
N-(5,6-Diphenyl-1,2,4-triazin-3-yl)-5-benzoylamino-1,3-diphenyl-4-(2-methoxyphenyl)-2-pyrazoline-
5-carbohydrazide (6b). Using the general procedure, 5b gave 6b (41%); mp. 210-212ºC; IR (cm-1):
3396, 3267 (NH str.), 3059, 3028 (aromatic CH str.), 2964, 2932, 2883, 2833 (OCH3 and pyrazolinyl
aliphatic CH str.), 3059, 3028, 2997 (aromatic CH str.), 1709 (hydrazide C=O str.), 1682 (amide C=O
str.), 1597(aromatic C=C str.), 1495, 1473, 1445 (NH bend.), 1358, 1331, 1290, 1252 (C-N str.), 1067,
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1028 (C-O str. of OCH3), 762, 692 (aromatic CH bend.); H-NMR (DMSO-d6) δ 11.23, 10.28 [2 brs,
2H (exch.), hydrazide NHNH], 7.97 [s, 1H (exch.), amide NH] 7.61-6.50 (m, 29H, ArH's), 5.87 (s, 1H,
pyrazolinyl CH), 3.60 (s, 3H, OCH3); 13C-NMR (DMSO-d6) δ 171.64, 164.30, (C=O), 157.28, 146.84,
142.78, 136.41 (C=N), 135.95, 134.76, 132.74, 132.49, 132.45, 132.41, 131.46 (aromatic C), 130.54,
129.70. 129.31, 129.20, 128.74, 128.64, 128.40, 128.29, 126.86, 126.08, 125.89, 121.68, 120.33,
115.15, 115.09, 114.99 (aromatic CH), 110.04 (pyrazolinyl C), 80.55 (pyrazolinyl CH), 55.04 (OCH3);
Anal. for C45H36N8O3 Calcd.: C, 73.35; H, 4.92; N, 15.21. Found: C, 73.50; H, 5.00; N, 15.40.
General procedure for the preparation of 4-aryl-5-benzoylamino-1,3-diphenyl-2-pyrazoline-5-
carbohydrazides (8a,b). To a suspension of each of compounds 5a,b (1 mmol) in methanol (20 mL)
was added 80% hydrazine hydrate (0.5 mL). While the reaction mixture of compound 8a was shaken
for ten minutes at room temperature, that of compound 8b was heated under reflux for one hour. The
reaction mixtures of each compound were then left overnight at room temperature. The colorless
precipitate formed was collected by filtration and recrystallized from methanol to give colorless
crystals of 8a,b.
5-Benzoylamino-1,3,4-triphenyl-2-pyrazoline-5-carbohydrazide (8a). Using the general procedure, 5a
gave 8a (73%); mp. 214-215ºC; IR (cm-1): 3400, 3325 (NH, NH2 str.), 3065, 3034 (aromatic CH str.),
2930 (pyrazolinyl CH str.), 1669 (C=O str.), 1625 (C=N str.), 1601 (aromatic C=C str.), 1503, 1480
(NH bend.), 1374, 1321, 1280, 1243 (C-N str.), 750, 696 (aromatic CH bend.); 1H-NMR (DMSO-d6) δ
10.05 [s, 1H (exch.), hydrazide NH], 8.07 [s, 1H (exch.), amide NH], 7.60-6.86 (m, 20H, ArH's), 5.32
(s, 1H, pyrazolinyl CH), 4.54[s, 2H (exch.), NH2]; MS m/z 475 (M+, 1.3%); Anal. for C29H25N5O2
Calcd.: C, 73.24; H, 5.30; N, 14.73. Found: C, 73.20; H, 5.25; N, 14.60.
5-Benzoylamino-1,3-diphenyl-4-(2-methoxyphenyl)-2-pyrazoline-5-carbohydrazide (8b). Using the
general procedure, 5b gave 8b (74%); mp. 230ºC; IR (cm-1): 3384, 3334,3284 (NH, NH2 str.), 3061,
3025 (aromatic CH str.), 2954, 2942, 2901, 2835 (OCH3 and pyrazolinyl aliphatic CH str.), 1684
(hydrazide C=O str.), 1672 (amide C=O str.), 1636 (C=N str.), 1604 (aromatic C=C str.), 1497, 1475
(NH bend.), 1375, 1294, 1250 (C-N str.), 1167, 1028 (C-O str. of OCH3), 750, 692 (aromatic CH
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bend.); H-NMR (DMSO-d6) δ 10.25 [s, 1H (exch.), hydrazide NH], 8.18 [s, 1H (exch.), amide NH],
7.56-6.49 (m, 19H, ArH's), 5.59 (s, 1H, pyrazolinyl CH), 4.61[s, 2H (exch.), NH2], 3.82 (s, 3H,
OCH3); MS m/z 505 (M+, 0.4%); Anal. for C30H27N5O3 Calcd.: C, 71.27; H, 5.38; N, 13.85. Found: C,
71.30; H, 5.50; N, 14.00.