Synthesis of 3-(3,4-dimethoxyphenyl)-1 H-1,2,4-triazole-5-thiol and 2-amino-5-(3,4-dimethoxyphenyl)-1,3,4-thiadiazole derivatives exhibiting anti-inflammatory activity.

New 1-acylderivatives of 5-alkylthio-3-(3,4-dimethoxyphenyl)-4H-1,2,4-triazole (5c-f, 6d-f) were synthesized by the acylation of 5-alkylthio-3-(3,4-dimethoxyphenyl)-4H-1,2,4-triazoles (3, 4) with acyl chlorides. The compounds 3, 4 were obtained by the alkylation of 3-(3,4-dimethoxyphenyl)-1H-1,2,4-triazole-5-thiol (2) sodium salt with alkyl iodides. Compound 2 and 2-amino-5-(3,4-dimethoxyphenyl)-1,3,4-thiadiazole (8) were prepared by the treatment of 3,4-dimethoxybenzoylthiosemicarbazide (1) with sodium hydroxide or acetyl chloride (and then sodium hydroxide), respectively. Related 2-acylamino-5-(3,4-dimethoxyphenyl)-1,3,4-thiadiazoles (7c, e, f) were synthesized by the acylation of compound 8 with acyl chlorides. 3-(3,4-Dimethoxyphenyl)-4-phenyl-4,5-dihydro-1H-1,2,4-triazole-5-thione (9) was N-acylated with acyl chlorides or S-methylated with iodomethane to give 1-acyl-3-(3,4-dimethoxyphenyl)-4-phenyl-4,5-dihydro-1H- 1,2,4-triazole-5-thiones (10a, b) or 3-(3,4-dimethoxyphenyl)-5-methylthio-4-phenyl-4H-1,2,4-triazole (11) respectively. The synthesized compounds 6d, 7a, c, 10a, b, 11 exhibit anti-inflammatory activity.