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Mohammed Amir et al.
obtained was separated, then filtered, washed with water,
dried and recrystallised from ethanol.
114.65 (2CHarom), 126.01 (CHarom), 127.44 (2CHarom),
128.63 (4CHarom), 128.76 (4CHarom), 129.58 (2CHarom), 138.8
(2CHarom), 153.56 (C5/arom), 160.16 (C3/arom), 168.7 (CHarom);
MS: m/z 373 (M+); Anal. Calcd for C22H19N3OS: C, 70.75;
H, 5.13; N, 11.25; Found: C, 70.59; H, 5.27; N, 11.13%.
5-(Diphenylmethyl)-4-(4-chlorophenyl)-3-mercapto(4H)-
1,2,4-triazole (4a)
Yield: 74%; mp 225°C; IR (KBr, cm−1): 2550 (SH), 1610
(C=N); 1H NMR (CDCl3) δ (ppm): 5.03 (s, 1H, CH), 6.94–
7.39 (m, 14H, ArH), 11.49 (bs, 1H, SH); 13C NMR (CDCl3)
δ (ppm): 48.5 (CH), 127.4 (2CHarom), 128.51 (4CHarom),
128.73 (4CHarom), 129.58 (2CHarom), 129.65 (2CHarom),
131.92 (CHarom), 135.61 (CHarom), 138.15 (2CHarom), 152.87
(C5/arom), 168.46 (C3/arom); MS: m/z 378 (M+), 380 (M++2);
Anal. Calcd for C21H16ClN3S: C, 66.75; H, 4.27; N, 11.12;
Found: C, 66.89; H, 4.16; N, 10.98%.
General method for synthesis of 5-(diphenylmethyl)-2-(4-
substituted phenyl)amino-1,3,4-thiadiazoles (5a–e)
e thiosemicarbazide (0.001 M) was added gradually
with stirring to polyphosphoric acid (12–15 mL) at 120°C
for 20 min. e reaction mixture was heated with stirring
for another 3 h and poured over crushed ice. e pre-
cipitated mass was filtered, washed with water, dried and
recrystallised from methanol.
5-(Diphenylmethyl)-2-(4-chlorophenyl)amino-1,3,4-
thiadiazole (5a)
5-(Diphenylmethyl)-4-(4-fluorophenyl)-3-mercapto (4H)-
1,2,4-triazole (4b)
Yield: 75%; mp: 115°C; IR (KBr, cm−1): 3388 (NH), 1636
(C=N); 1H NMR (CDCl3) δ (ppm): 5.61 (s, 1H, CH), 7.25–
7.87 (m, 14H, ArH), 7.97 (s, 1H, NH); 13C NMR (CDCl3)
δ (ppm): 51.47 (CH), 116.46 (2CHarom), 116.78 (2CHarom),
127.92 (2CHarom), 129.35 (4CHarom), 129.57 (4CHarom),
137.76 (CHarom), 142.35 (2CHarom), 156.68 (CHarom), 162.47
(C5/arom), 165.37 (C2/arom); MS: m/z 378 (M+), 380 (M++2);
Anal. Calcd for C21H16ClN3S: C, 66.75; H, 4.27; N, 11.12;
Found: C, 66.58; H, 4.12; N, 11.29%.
Yield: 70%; mp: 245°C; IR (KBr, cm−1): 2680 (SH), 1588
(C=N); 1H NMR (CDCl3) δ (ppm): 5.12 (s, 1H, CH), 6.97–
7.45 (m, 14H, ArH), 11.53 (bs, 1H, SH); 13C NMR (CDCl3)
δ (ppm): 47.89 (CH), 118.37 (2CHarom), 119.69 (2CHarom),
128.73 (2CHarom), 131.25 (4CHarom), 131.86 (4CHarom),
136.67 (CHarom), 140.17 (2CHarom), 147.36 (CHarom), 152.63
(C5/arom), 168.25 (C3/arom); MS: m/z 361 (M+); Anal. Calcd
for C21H16FN3S: C, 69.78; H, 4.27; N, 11.63; Found: C, 69.64;
H, 4.16; N, 11.51%.
5-(Diphenylmethyl)-2-(4-fluorophenyl)amino-1,3,4-
thiadiazole (5b)
5-(Diphenylmethyl)-4-(3-chloro-4-flurophenyl)-3-mercapto
(4H)-1,2,4 triazole (4c)
Yield: 65.5%; mp: 132°C; IR (KBr, cm−1): 3346 (NH), 1632
(C=N); 1H NMR (CDCl3) δ (ppm): 5.67 (s, 1H, CH), 7.34–
7.91 (m, 14H, ArH), 8.03 (s, 1H, NH); 13C NMR (CDCl3)
δ (ppm) 51.28 (CH), 115.97 (2CHarom), 116.19 (2CHarom),
127.59 (2CHarom), 129.03 (4CHarom), 129.11 (4CHarom),
137.59 (CHarom), 141.99 (2CHarom), 156.46 (CHarom), 162.22
(C5/arom), 165.13 (C2/arom); MS: m/z 361 (M+); Anal. Calcd.
for C21H16FN3S: C, 69.78; H, 4.46; N, 11.63; Found: C, 69.59;
H, 4.37; N, 11.52%.
Yield: 62%; mp: 252°C; IR (KBr, cm−1): 2650 (SH), 1610
(C=N); 1H NMR (CDCl3) δ (ppm): 5.19 (s, 1H, CH), 7.09–
7.52 (m, 14H, ArH), 11.63 (bs, 1H, SH); 13C NMR (CDCl3)
δ (ppm): 45.47 (CH), 111.64 (CHarom), 111.95 (CHarom),
114.35 (CHarom), 115.98 (CHarom), 122.84 (2CHarom), 123.93
(4CHarom), 124.37 (4CHarom), 131.27 (CHarom), 133.98
(2CHarom), 149.76 (CHarom), 151.13 (C5/arom), 163.41
(C2/arom); MS: m/z 396 (M+), 398 (M++2); Anal. Calcd for
C21H15ClFN3S: C, 63.71; H, 3.82; N, 10.61; Found: C, 63.62;
H, 3.7; N, 10.52%.
5-(Diphenylmethyl)-2-(3-chloro-4-fluorophenyl)amino-1,3,4-
thiadiazole (5c)
5-(Diphenylmethyl)-4-(4-methylphenyl)-3-mercapto(4H)-
1,2,4-triazole (4d)
Yield: 58%; mp: 113°C; IR (KBr, cm−1): 3343 (NH), 1612
(C=N); 1H NMR (CDCl3), δ (ppm): 5.72 (s, 1H, CH), 7.41–
7.97 (m, 14H, ArH) 8.14 (s, 1H, NH); 13C NMR (CDCl3)
δ (ppm): 48.12 (CH), 112.35 (CHarom), 112.68 (CHarom),
115.63 (CHarom), 116.12 (CHarom), 123.59 (2CHarom),
124.54 (4CHarom), 124.97 (4CHarom), 132.32 (CHarom),
134.84 (2CHarom), 152.43 (CHarom), 161.57 (C5/arom), 165.21
(C2/arom); MS: m/z 396 (M+), 398 (M++2); Anal. Calcd for
C21H15ClFN3S: C, 63.71; H, 3.82; N, 10.61; Found: C, 63.56;
H, 3.71; N, 10.49%.
Yield:80%,mp:254°C;IR(KBr,cm−1):2564(SH),1623(C=N);
1H NMR (CDCl3) δ (ppm): 2.39 (s, 3H, CH3), 5.05 (s, 1H,
CH), 6.88–7.31 (m, 14H, ArH), 11.35 (bs, 1H, SH); 13C NMR
(CDCl3) δ (ppm): 20.63 (CH3), 48.42 (CH), 127.64 (2CHarom),
128.71 (4CHarom), 128.93 (4CHarom), 129.87 (2CHarom), 130.16
(2CHarom), 132.17 (CHarom), 135.84 (CHarom), 138.34 (2CHarom),
152.96(C5/arom), 168.75 (C3/arom); MS: m/z 357 (M+); Anal.
Calcd for C22H19N3S: C, 73.92; H, 5.36; N, 11.75; Found: C,
73.78; H, 5.24; N, 11.87%.
5-(Diphenylmethyl)-4-(4-methoxyphenyl)-3-mercapto(4H)-
1,2,4-triazole (4e)
5-(Diphenylmethyl)-2-(4-methylphenyl)amino-1,3,4-
thiadiazole (5d)
Yield: 81%, mp: 232°C; IR (KBr, cm−1): 2557 (SH), 1608
(C=N); 1H NMR (CDCl3) δ (ppm): 3.83 (s, 3H, OCH3), 5.05
(s, 1H, CH), 6.88–7.32 (m, 14H, ArH), 10.78 (bs, 1H, SH);
13C NMR (CDCl3) δ (ppm): 48.49 (CH), 55.57 (OCH3),
Yield: 75.6%, mp: 130°C; IR (KBr, cm−1): 3337 (NH), 1623
1
(C=N); H NMR (DMSO d6) δ (ppm): 2.29 (s, 3H, CH3),
5.62 (s, 1H, CH), 7.09–7.34 (m, 14H, ArH), 7.78 (s, 1H, NH);
13C NMR (DMSO d6) δ (ppm): 25.54 (CH3), 56.96 (CH),
Journal of Enzyme Inhibition and Medicinal Chemistry