Synthesis and Characterization of New Triheterocyclic Compounds Consisting of l,2,4-Triazol-3-one,1,3,4-Thiadiazole and 1,3,4-Oxadiazole Rings

摘要

A series of acetic acid derivatives (2a-c) was synthesized by the condensation of compounds la-c with chloroacetic acid.The treatment of carboxylic acid derivatives with thiosemicarbazide in phosphorus oxychloride and subsequent diazotation of the products (3a-c) afforded 5-alkyl-2-[(5-chloro-l,3,4-thiadiazol-2-yl)methyl]-2,4-dihydro-3.H-l,2,4-triazol-3-one derivatives (4a-c).The treatment of compounds 4a-c with thiourea produced 5-alkyl-2-[(5-mercapto-l,3,4-thiadiazol-2-yl)methyl]-2,4-dihydro-3H-l,2,4-triazol-3-one derivatives (5a-c).Subsequently,compounds 5a-c were converted to acid hy-drazides by treatment with hydrazine hydrate after esterification (7a-e).Moreover,the reaction of compounds 7a-c with carbon disulfite in the presence of KOH afforded 5-alkyl-2-[(5-{[(5-mercapto-l,3,4-oxadiazol-2-yl)methyl]thio}-l,3,4-thiadiazol-2-yl)methyl]-2,4-dihydro-3H-l,2,4-triazol-3-ones (8a-c).