A facile and efficient one-pot three-step protocol for synthesis of 6-aryl-7-oxo-5-aryoxy/alkoxy-1-(p-tolyl)-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidine-3-carbonitrile

Abstract

A facile and efficient one-pot three-step approach to the synthesis of substituted 1H-pyrazolo [4,3-d]pyrimidin-7(6H)-ones 4 from ethyl 3-cyano-1-(p-tolyl)-4-((triphenylphosphoranylidene)amino)-1H-pyrazole-5-carboxylate 1 has been developed. In this method, treatment of phospazene 1 with arylisocyanates and followed by nucleophilic addition with phenols/alcohols in the presence of a catalytic amount of K 2 CO 3 /R 2 ONa in THF at room temperature gave the corresponding 6-aryl-7-oxo-5-aryoxy/alkoxy-1-(p-tolyl)-6,7-dihydro-1H-pyrazolo[4,3-d]-pyrimidine-3-carbonitrile 4 in satisfactory to good yields.