A one-pot and efficient method for the synthesis of pyrazolo[4',3':5,6]pyrido[2,3-d]pyrimidine-dione derivatives by condensation reaction of barbituric acids, 1H-pyrazol-5-amines and aldehydes under solvent-free conditions is reported. These products were evaluated in vitro for their antibacterialactivities.
Some fused heterocyclic pyrimidines have been synthesized in high yields using ultrasound irradiation in a one-pot, three-component and efficient process by condensation reaction of barbituric acids, aldehydes and a series of enamines in water. Prominent among the advantages of this new method are operational simplicity, good yields in short reaction times and easy work-up procedures employed. (C) 2009 Elsevier B.V. All rights reserved.