Facile one-pot synthesis of pyrido[2,3-d]pyrimidine derivatives over ZrO2 nanoparticles catalyst

An efficient synthesis of hexahydropyrido[2,3-d]pyrimidinetrione derivatives is achieved via tandem Knoevenagel-Michael addition of aromatic aldehydes,methylcyanoacetate and 4(6)-aminouracil in solvent-free conditions in the presence of 10 mol％ of ZrO2 nanoparticles (ZrO2 NPs) as a heterogenous catalyst.The procedure is formed in high yields,short reaction time and an environmentally friendly specificity.