One-Pot Synthesis of 5-Alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2- ones Catalyzed by Phosphotungstic Acid

Many dihydropyrimidinones and their derivatives play an important role in medicine due to their therapeutic and pharmacological properties. 1] They have emerged as the integral backbones of several calcium channel blockers, antihypertensive agents, alpha-1α-antagonists. 2] Strategies for the synthesis of dihydropyrimidinone nucleus have varied from one-pot to multistep approaches. Although high yields can be achieved by the following complex multistep procedures, these methods lack the simplicity comparing with Biginelli protocol which firstly reported by Biginelli by one-pot condensation of aryl aldehyde, β-ketoesters and urea with catalytic acid in 1993, and these multistep methods suffer from low yields particularly for substituted aromatic aldehyde.