Bismuth subnitrate catalyzed efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones: An improved protocol for the Biginelli reaction

An efficient synthesis of 3,4-dihydropyrimidinones (DHPMs) using bismuth subnitrate as the catalyst for the first time from an aldehyde, beta-ketoester, and urea in acetonitrile is described. This new method consistently has the advantage of excellent yields (88-96%) and short reaction times (1.5-4h) than do classical Biginelli reaction conditions.