A clean procedure for synthesis of pyrido[d]pyrimidine derivatives under solvent-free conditions catalyzed by ZrO(2) nanoparticles.

A simple one-pot method for the preparation of 7-amino-2,4-dioxo-5-aryl-1,2,3,4-tetrahydropyrido[2,3- d]pyrimidine-6-carbonitriles 4 from aromatic aldehydes, malononitrile and 4(6)-aminouracil in the presence of ZrO2 nanoparticles (ZrO2 NPs) as an efficient heterogeneous catalyst is described. The procedure has the advantages of high yields (86-97%), short reaction time (2h) and an environmentally friendly specificity.