<i>N</i>-(Phenylsulfonyl)Benzenesulfonamide: A New Organocatalyst for One-Pot, Solvent-Free Synthesis of Biginelli’s 3,4-Dihydropyrimidine-2(1<i>H</i>)-Thiones

This report describes an efficient method for one-pot, three-component coupling of aldehydes, β-ketoesters/β-diketone, and urea/thiourea catalyzed by <i>N</i>-(phenylsulfonyl)benzene sulfonamide (NPBSA) as efficient organocatalyst to afford the corresponding 3,4-dihydropyrimidine-2(1<i>H</i>)-ones/thiones via Biginelli condensation. Novel catalyst, high yields, quick reaction time, solvent-free environment, simple workup, and the ability to tolerate a variety of functional groups are some of the advantages of the current method, providing economic and environmental benefits. The present work also includes the synthesis of active pharmaceutical ingredient Piperasterol as application of the method.