An Efficient Biginelli One-Pot Synthesis of New Benzoxazole-Substituted Dihydropyrimidinones and Thiones Catalysed by Alumina-Supported Trifluoromethane Sulfonic Acid Under Solvent Free Conditions
An efficient synthesis of benzoxazole-substituted 3,4-dihydropyrimidinones (DHPMs) using alumina supported trifluoromethane sulfonic acid as the catalyst for the first time from an aldehyde, P-keto ester, and benzoxazole-substituted urea and thiourea under solvent-free conditions is described. When compared with the classical Biginelli reaction conditions, this new method consistently has the advantage of excellent yields (80-93%) and short reaction time (30-120 Minutes) at 120 degrees C temperature.