Synthesis Of Green Dihydropyrimidinones Compounds

The Biginelli reaction is a one-pot acid catalysed cyclocondensation of β-ketoester, urea and aromatic aldehyde which leads to the synthesis of3,4-dihydro-pyrimidinones (DHPMs) which have great officinal value. A large number ofresearchers have shown persistent attention to the study of Biginelli reaction onaccount of its significant biological and pharmaceutical activities of DHPMs and itsderivatives.At the same time, seeking the diversity of structures of DHPMs viachanging the reactants and high yield of resultants changing with reaction conditions(including different catalysts and techniques and so on) is hot in researchs.We report herein the microwave-assisted and TsOH-catalyzed synthesis of C (5)substituted-3,4-dihydropyrimidin-2-ones(-thiones) via the Biginelli reaction fromaldehydes, p-toluoylacetone, and urea or thiourea under solvent-free conditions.1.21different5-Methylbenzoylsubstituted3,4-dihydropyrimidin-2-ones (-thiones)can be obtained through the microwave-assisted and TsOH-catalyzed synthesis via theBiginelli reaction from aldehydes, p-methyl benzoylacetone and urea or thioureaunder solvent-free conditions.2.22different5-Benzoylsubstituted3,4-dihydropyrimidin-2-ones(-thiones) can beobtained through the microwave-assisted and TsOH-catalyzed synthesis via theBiginelli reaction from aldehydes, benzoylacetone, and urea or thiourea undersolvent-free conditions.3.5different5-Acetylsubstituted3,4-dihydropyrimidin-2-ones(-thiones) can beobtained through the microwave-assisted and TsOH-catalyzed synthesis via theBiginelli reaction from aldehydes, acetylacetone, and urea or thiourea undersolvent-free conditions.The present environmentally benign protocol of the synthesis of C(5)-acylsubstituted-3,4-dihydropyrimidin-2-ones(-thiones) is characteristic of short reactiontimes, high yields, simple and easy work-up, and without chromatographic separation.At the same time, it has expanded the molecule libraryof such compounds and laid the theoretical foundation for the research of the biological activity and pharmacologicalactivity.