Microwave assisted synthesis of some new Schiff’s bases from 2,4-dihydro-3H-1,2,4-triazol-3-one

Abstract

In this manuscript, a new series of 1,2,4-triazole-3-ones containing imin function was synthesized from 5-(4-bromobenzyl)-4-amino-2H-1,2,4-triazol-3(4H)-one and aromatic aldehyde by using microwave irradiation technique via schiff base reaction. Firstly, ethyl imido-p-bromophenylacetate hydrochloride (2) was synthesized according to the pinner method in the literature. Then, compound 2 was reacted with ethyl carbazate to synthesized ethyl p-bromophenylacetate etoxycarbonylhydrazone (3) compound. Then, 5-(4-bromobenzyl)-4- amino-2H-1,2,4-triazol-3(4H)-one (4) was synthesized from the reaction of ethyl p-bromophenylacetate etoxycarbonylhydrazone (3) with hydrazine monohydrate. Then, it was converted to their corresponding triazole containing Schiff bases (5a-e) with the reaction of corresponding aromatic aldehydes in ethanol by using the microwave irradiation method. This microwave technique has some advantages, including rapid and uniform heating, higher product yield and purity, mild reaction conditions, low energy requirement and shorter reaction time. The chemical structures of newly synthesized triazole containing schiff bases were identified using IR, 1HNMR, and mass spectroscopy data.