Synthesis of novel spiro-fused pyrazolo[4 ',3 ':5,6]pyrido[2,3-d]pyrimidines

New pyrazolo[4 ',3 ':5,6]pyrido[2,3-d]pyrimidines, with an associated spiro-3,3 '-oxindole attachment, were prepared by three-component combinations of 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinoline-1,2-dione with a pair of reactants chosen from a pyrazol-5-one, a pyrazole-5-amine, a barbituric acid, or a 6-aminouracil.