Imidazo[2,1-b][1,3,4]thiadiazoles: Microwave-assisted synthesis, gas phase thermolysis and integrative mechanistic approach

Abstract

The present study, deals with the synthesis of 2-substituted-6-phenyl-imidazo[2,1-b][1,3,4]thiadiazoles from 2-amino-5-substituted-1,3,4-thiadiazoles and 2-bromo-1-phenylethanone, which was carried out applying a microwave-assisted aqueous procedure. Furthermore, the gas-phase thermal behaviour of these imidazothiadiazoles in flash vacuum pyrolysis reactions has been studied. It has been shown that thermolysis conditions induce thiadiazole fragmentation to give indole-carbonitriles and other nitriles. The quantum chemical calculations support a stepwise mechanism for the fragmentation of imidazothiadiazoles to afford products.