Efficient one-pot synthesis of pyrido[2,3-d]pyrimidines catalyzed by nanocrystalline MgO in water

The direct three-component condensation of 6- aminouracil, 6-amino-2-thiouracil or 6-amino-1,3- dimethyluracil, with arylaldehydes and malononitrile to generate a series of pyrido[2,3-d]pyrimidine derivatives has been carried out over nanocrystalline MgO with high efficiency in water as a green solvent at 80 C. The morphology and structure of the nanocrystalline MgO were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results confirmed the nanocrystalline MgO particle size is approximately 50 nm. This methodology offers significant improvements for the synthesis of pyrido[2,3-d]pyrimidine derivatives with regard to the yield of products, simplicity in operation, and green aspects by avoiding toxic catalysts and solvents.