One-Pot Multicomponent Synthesis of Pyrazolo[3,4-d]pyrimidine-6-one Derivatives

An environmentally benign, simple, and efficient procedure has been developed for the one-pot multicomponent synthesis of pyrazolo[3,4-d]pyrimidine-6-one derivatives by the reaction of the variety of aryl-aldehydes, 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, and urea in the presence of catalytic amount of poly(N-vinylpyridinium) hydrogen sulfate in glycerol. The present method affords non-toxic and non-corrosive medium, short reaction times, high yield of the products, mild reaction conditions as well as simple experimental and isolation procedures. The catalyst can be recycled by simple filtration and reused without any significant reduction in its activity.