Microwave-Assisted Bronsted Acidic Ionic Liquid-Promoted One-Pot Synthesis of Heterobicyclic Dihydropyrimidinones by a Three-Component Coupling of Cyclopentanone, Aldehydes, and Urea

A simple and efficient method has been developed for the synthesis of heterobicyclic dihydropyrimidinone derivatives through a solvent-free one-pot three-component condensation of aromatic aldehydes, cyclopentanone, and urea or thiourea in the presence of Bronsted acidic ionic liquid under microwave irradiation. The catalyst can be reused at least six times without any noticeable decrease in catalytic activity.