Studies on pyrazolo(3,4-d]pyrimidine derivatives. XVIII. 1 facile preparation of 1H-pyrazolo[3,4-d]pyrimidin-4(5H)-ones

Abstract

Reaction of 5-amino-1-phenyl-1H-pyrazole-4-carboxamide (4) with the esters (3a-h) In the presence of sodium ethoxide in ethanol gave 1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one (1a) and its 6-substituted derivatives (1b-h). Similar treatment of 5-amino-1-methyl-1H-pyrazole-4-carboxamlde (5) with 3a-h gave the 1-methyl-1H-pyrazolo[3,4-d]-pyrimidln-4(5H)-ones (2a-h). © 1990.