An Ionic Liquid-Based Green Synthesis Strategy: Synthesis of Dihydropyrimidinones by Three-Component Biginelli-Type Reaction of Aliphatic Aldehydes, Aromatic Aldehydes and Urea

A Biginelli-type reaction involving aliphatic aldehydes, aromatic aldehydes, and urea was performed at high concentration with high regioselectivity to give a range of highly diverse 3,4-dihydropyrimidin-2-(1H)-one products in 58-88% yields, where a 30% aqueous solution of ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate) was employed as a green reaction medium. The catalyst can be easily recycled and reused with similar efficacy for at least four cycles.