Synthesis of some substituted diazoles and triazoles from primary amines

Abstract

In this paper the synthesis of substituted 1,3,4-oxadiazoles, thiadiazole and 1,2,4-triazoles. Cyclohexyl and hexylamine were treated with methyl chlorofomate to give the corresponding methyl N-alkyl carbamate (1,2), which converted to 4-alkyl semicarbazide (3,4) by their reaction with hydrazine hydrate in ethanol. Compounds (3,4) were treated with ammonium thiocyanate / hydrochloric acid to give substituted thiosemicarbazides (5,6). The thiosemicarbazides were treated with concentrated sulfuric acid or sodium hydroxide solution to give 5-amino-2-methyl amino-1,3,4-thiadiazole (9,10) and 5-methyl amino-1,2,4-triazoles-3-thiol (11,12) respectively. The substituted thiosemicarbazide was converted to 3,4-diamino-5-methyl amino-1,2,4-triazole (16) by its reaction with hydrazine hydrate. Compounds (3,4) were treated with carbon disulfide in potassium hydroxide to give substituted oxadiazoles (7,8). The reaction of 1,3,4-oxadiazoles with hydrazine hydrate gave substituted 1,2,4-triazoles (13,14), while compound (3) gave 4-amino-3,5-dicyclohexyl amino-1,2,4-triazole (15) upon heating at 90-120 C.The structure of the synthesized compounds were confirmed by spectral and physical methods.