HBF4-catalyzed Biginelli reaction: One-pot synthesis of dihydropyrimidin-2(1H)-ones under solvent-free conditions

An efficient synthesis of dihydropyrimidinones from the aldehyde, 1,3-dicarbonyl compound and urea (thiourea) under solvent-free conditions, using fluoroboric acid as the catalyst, is described. Compared with the classical Biginelli reaction conditions, this new protocol has the advantage of high yields, short reaction time and simplicity in the experimental procedure.