Synthesis and Evaluation of Polycyclic Pyrazolo[3,4-d]pyrimidines as PDE1 and PDE5 cGMP Phosphodiesterase Inhibitors.

Polycyclic pyrazolo[3,4-d]pyrimidines (represented by 3 and 4) were synthesized as analogues of the recently reported polycyclic guanine phosphodiesterase (PDE) inhibitors. From the structure−activ...