Use of Ester Formylhydrazones for the Synthesis of 1,2,4-triazole and 1,3,4-oxadiazole Derivatives

Abstract

A series of ester formylhydrazones were synthesised by the reaction of alkyl imidate hydrochlorides with formyl-hydrazine. Treatment of the ester formylhydrazones with acetic acid hydrazide, isonicotinic acid hydrazide, nicotinic acid hydrazide, and 4-hydroxybenzhydrazide resulted in the formation of either 4-acylamino-4H-1,2,4-triazoles or 2,5-disubstituted 1,3,4-oxadiazoles. 3-Alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones were synthesised by the reaction of the ester formylhydrazones with carbohydrazide. Some arylidenamino compounds were synthesised by the reaction of 4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones with several aldehydes. These compounds were characterised by elemental analyses, IR, ¹H NMR, and UV spectral techniques.