Med Chem Res (2013) 22:3341–3349
3347
4-[(3-Fluoro-benzylidine)-amino]-2-[4-(5-mercapto-
[1,3,4]oxadiazol-2-yl)phenyl]-5-methyl-2,4-dihydro-
[1,2,4]triazol-3-one (10b)
2-[4-(5-Mercapto-[1,3,4]oxadiazol-2-yl)phenyl]-5-methyl-
4-[(1H-pyrrol-2-ylmethylene)-amino]-2,4-dihydro-
[1,2,4]triazol-3-one (10f)
1
Reddish brown solid; (76 %); m.p. 276–277 ꢁC. H-NMR
Brownish solid; (71 %); m.p. 249–250 ꢁC; 1H-NMR
(300 MHz, DMSO-d6) d 14.75 (brs, 1H, oxadiazole-SH),
11.77 (s, 1H, pyrrole-NH), 9.30 (s, 1H, N=CH), 8.13 (d, 2H,
J = 8.91 Hz, Ar–H), 7.9 (d, 2H, J = 8.91 Hz, Ar–H), 7.12(s,
1H, pyrrole–H), 6.75 (s, 1H, pyrrole–H), 6.75 (s, 1H, pyrrole–
H), 2.38 (s, 3H, triazole–CH3); MS: m/z 367.4 [M?1]; Anal.
Calculated for C16H12N7O2S: C. 52.45, H. 3.30, N. 26.76;
S. 8.75; Found C. 52.44, H. 3.32, N. 26.70, S. 8.74 %.
(300 MHz, DMSO-d6) d 14.75 (s, 1H, oxadiazole–SH),
9.74 (s, 1H, N=CH), 8.13 (d, 2H, J = 8.85 Hz, Ar–H), 7.99
(d, 2H, J = 8.91 Hz, Ar–H), 7.74–7.71 (m, 2H, Ar–H),
7.61–7.56 (m, 1H, Ar–H), 7.42–7.37 (m, 1H, Ar–H), 2.43
(s, 3H, triazole–CH3); MS: m/z 397 [M?1]; Anal. Calcu-
lated for C18H13FN6O2S: C. 54.54, H. 3.31, N. 21.20,
S. 8.09; Found: C. 54.50, H. 3.30, N. 21.24, S. 8.10 %.
2-[4-(5-Mercapto-[1,3,4]oxadiazol-2-yl)phenyl]-5-methyl-
4-[(thiazol-4-ylmethylene)-amino]-2,4-dihydro-
[1,2,4]triazol-3-one (10g)
4-[(4-Fluoro-benzylidine)-amino]-2-[4-(5-mercapto-
[1,3,4]oxadiazol-2-yl)phenyl]-5-methyl-2,4-dihydro-
[1,2,4]triazol-3-one (10c)
Brownish solid; (68 %); m.p. 289–290 ꢁC; 1H-NMR
(400 MHz, DMSO-d6) d 14.75 (brs, 1H, Oxadiazol–SH),
9.81 (s, 1H, thiazole–H), 9.27 (s, 1H, N=CH), 8.49 (s, 1H,
thiazole–H), 8.13 (d, 2H, J = 8.84 Hz, Ar–H), 7.99 (d, 2H,
J = 8.84 Hz, Ar–H), 2.41 (s, 3H, triazole–CH3); MS:
m/z 386 [M?1]; Anal. Calculated for C15H11N7O2S2:
C. 46.74, H. 2.88, N. 25.44, S. 16.44; Found: C. 46.69,
H. 2.90, N. 25.47, S. 16.41 %.
Brownish solid; (77 %); m.p. 272–273 ꢁC. 1H-NMR
(300 MHz, DMSO-d6) d 14.75 (s, 1H, oxadiazole–SH),
9.70 (s, 1H, N=CH), 8.12 (d, 2H, J = 8.9 Hz, Ar–H),
8.00–7.98 (m, 4H, Ar–H), 7.38 (m, 2H, Ar–H), 2.42 (s, 3H,
triazole–CH3); MS: m/z 397 [M?1]; Anal. Calculated for
C18H13FN6O2S: C. 54.54, H. 3.31, N. 21.20, S. 8.09;
Found: C. 54.60, H. 3.33, N. 21.20, S. 8.10 %.
Synthesis of 4-amino-2-[4-amino-5-mercapto-4H-
[1,2,4]triazol-3-yl)-phenyl]-5-methyl-2,4-dihydro-
[1,2,4] triazol-3-one (11)
4-[(2,5-Difluoro-benzylidine)-amino]-2-[4-(5-mercapto-
[1,3,4]oxadiazol-2-yl)phenyl]-5-methyl-2,4-dihydro-
[1,2,4]triazol-3-one (10d)
A mixture of (11) (2 mmol) in hydrazine hydrate (10 mL)
was stirred at reflux for 12 h. The reaction mixture was
cooled and solid formed was filtered and dried under
vacuum to afford compound (11) as an off white solid.
(70 %); m.p. 284–285 ꢁC. 1H-NMR (400 MHz, DMSO-d6)
d 14.73 (brs, 1H, triazole-SH), 8.12 (d, 2H, J = 11.86 Hz,
Ar–H), 2.24 (s, 3H, triazole–CH3); 13C-NMR (100 MHz,
DMSO-d6) d 167.3, 151.9, 149.4, 147.8, 139.8, 129.4,
122.2, 117.3, 11.3; MS: m/z 305 [M?1]; Anal. Calculated
for C11H12N8OS: C. 43.41, H. 3.97, N. 36.82, S. 10.54.
Found: C. 43.45, H. 3.98, N. 36.77, S. 10.53 %.
Brownish solid; (79 %); m.p. 255–256 ꢁC. 1H-NMR
(300 MHz, DMSO-d6) d 14.73 (s, 1H, oxadiazole–SH),
9.94 (s, 1H, N=CH), 8.12 (d, 2H, J = 8.9 Hz, Ar–H), 7.80
(m, 1H, Ar–H), 7.48 (m, 2H, Ar–H), 2.45 (s, 3H, triazole–
CH3); MS: m/z 413 [M-1]; Anal. Calculated for
C18H12F2N6O2S: C. 52.17, H. 2.92, N. 20.28, S. 7.74;
Found: C. 52.15, H. 2.90, N. 20.31, S. 7.78 %.
4-[(2-Bromo-benzylidine)-amino]-2-[4-(5-mercapto-
[1,3,4]oxadiazol-2-yl)phenyl]-5-methyl-2,4-dihydro-
[1,2,4]triazol-3-one (10e)
Biological activity
1
Reddish brown solid; (75 %); m.p. 288–289 ꢁC; H-NMR
The in vitro antimicrobial activity was carried out by disc
diffusion method in dimethylformamide (DMF) as solvent.
All the newly synthesized compounds were screened for
antimicrobial activity against B. subtilis (NICM 2063),
S. aureus(NICM 2079), S. epidermidis (NICM 2493),
E. coli (NICM 2138), Pseudomonas aeruginosa (NICM
2036) and the antifungal activity against Rhizopus oryzae
(NICM 997), Aspergillus niger (NICM 572),A.
(300 MHz, DMSO-d6) d 14.78 (s, 1H, oxadiazole–SH),
10.16 (s, 1H, N=CH), 8.15 (d, 2H, J = 8.52 Hz, Ar–H),
8.09 (m, 1H, Ar–H), 7.99 (d, 2H, J = 8.52 Hz, Ar–H), 7.78
(d, 1H, Ar–H), 7.54–7.48 (m, 2H), 2.44 (s, 3H, triazole–
CH3); MS: m/z 456 [M], 458 [M?2]; Anal. Calculated for
C18H13BrN6O2S: C. 47.28, H. 2.87, N. 28.38, S. 7.01;
Found: C. 47.31, H. 2.86, N. 28.30, S. 6.98 %.
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