Solvent-free sonochemical multi-component synthesis of benzopyranopyrimidines catalyzed by polystyrene supported p-toluenesulfonic acid

An efficient and environment-friendly method for the synthesis of benzopyranopyrimidines has been developed using the ultrasound-mediated condensation of salicylic aldehydes, malononitrile and secondary amines under solvent-free condition at room temperature in the presence of polystyrene supported p-toluenesulfonic acid to give the desired product in good to excellent yield. This procedure gives several advantages over current methods including a simple work-up, cost effectiveness, are usable catalyst and shorter reaction times.