Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Catalyzed by Nafion-H Under Ultrasound Irradiation and Solvent-Free Conditions

A novel synthesis of 3,4-dihydropyrimidin-2-(1H)-ones by one-pot cyclocondensation of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea using nafion-H as the catalyst under ultrasound irradiation and solvent-free conditions was developed. Compared with the classical Biginelli reactions, this method consistently enjoys the advantages of mild reaction conditions, excellent yields, easy work up and short reaction time