Synthesis of pyrano[2,3-d]pyrimidine derivatives has been achieved by one-pot three component condensation reactions of various aromatic aldehydes, malononitrile and barbituric acid in aqueous methanol using yttrium oxide (Y2O3) as a catalyst. The potential application of Y2O3 in various synthesis increasing rapidly due to its reaction simplicity, minimum reaction time, high yields, environment friendly procedure and low cost of chemicals. The reactants are completely soluble in 70 % aqueous methanol and afford high yield of products.