Solvent-Free Synthesis of Dihydropyrimidinones Catalyzed by Alumina Sulfuric Acid at Room Temperature

A simple, efficient and practical procedure for the Biginelli reaction using alumina sulfuric acid (ASA) as a novel acid catalyst is described under solvent-free conditions. The catalyst exhibited remarkable reactivity at room temperature. The method offers several advantages including high yields, environmentally friendly procedure, short reaction times and simple work up procedure