A flexible one-pot synthesis of 8,10-dimethyl-12-aryl-9H-naphto[1',2':5,6]pyrano[2,3-d]pyrimidine-9,11-diones catalyzed by ZnO nanoparticles under solvent-free conditions

A new, convenient, and green procedure for the synthesis of naphthopyranopyrimidine-diones is described using a one-pot multi-component reaction of beta-naphthol, 1,3-dimethylbarbituric acid, and various aryl aldehydes in the presence of ZnO nanoparticles, an effective and recyclable heterogeneous catalyst, under solvent-free conditions. This method provides excellent advantages, such as waste-free, simple work-up procedure, and excellent yield with high selectivity. The stability of the catalyst was investigated by determining its activity after recycling for six times without significant loss of its catalytic activity.