Several approaches to cyanide ion-catalyzed synthesis of 4-aroyl-1-phenyl-1H-pyrazolo[3,4-d]pyrimidines

4-Aroyl-1-phenyl-1H-pyrazolo[3,4-d]pyrimidines (5) were formed in low yields by reaction of 4-chloro-1-phenyl-1H-pyrazolo[3,4-d]pyrimidine (4) with arenecarbaldehydes (3) in the presence of potassium cyanide. Similar reaction of 4-tosyl-1-phenyl-1H-pyrazolo [3,4-d]pyrimidine (9) with 3 gave the ketones (5) in higher yields (60-74%). In the presence of catalytic amounts of both sodium p-toluenesulfinate (10) and potassium cyanide, the reaction of 4 with 3 gave the ketones (5) in good yields.