Microwave-assisted oxidation of 3,4-dihydropyrimidin-2(1H)-ones

Abstract

A new facile cost-effective method for the oxidation of acetyl and carboethoxy derivatives of 3,4dihydropyrimidin-2(1H)-ones (DHPMs) by using potassium peroxydisulfate in water as solvent under microwave irradiation has been developed. Whereas the presence of the acetyl group instead of the carboethoxy group in position 5 decreases the rate of oxidation, the nature of the additional subtituent (electron-donating or electron-withdrawing group) and its location on the phenyl ring (ortho-, meta- or para-position) attached to C-4 of the dihydropyrimidinone ring influence the rate of reaction. Increase in the rate of the reaction compared with that of the reaction under reflux condition is the advantage of the use of microwave irradiation for this oxidation method.