Brønsted Acidic Ionic Liquid: An Efficient and Reusable Catalyst for the Multi-Component Synthesis of Dihydropyrimidinones under Solvent-Free Conditions

An efficient and convenient procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones by condensation of 1,3-dicarbonyl compounds, Aromatic and aliphatic aldehydes, and urea or thiourea in the presence of catalytic amount of Brønsted acidic ionic liquid 3-methyl-1-sulfonic acid imidazolium chloride {[Msim]Cl} under thermal solvent-free conditions reacted easily to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones and thiones. Straightforward and clean workup, short reaction time, good to excellent yields and reusability of the catalyst are the advantages of this method.