Phenylphosphinic acid-catalyzed synthesis of 6-unsubstituted dihydropyrimidinones under solvent-free conditions

Phenylphosphinic acid is found to catalyze the three-component condensation of an aldehyde, enaminone, and urea or thiourea to afford the corresponding 6-unsubstituted dihydropyrimidinones in high to excellent yields. This methodology is simple and fast synthetic route for the preparation of interesting class of heterocycles.