5-(2-substituted-5-heterocyclylsulphonylpyrid-3-YL)- dihydropyrazolo[4,3-d]pyrimidin-7-ones as phosphodiesterase inhibitors

摘要

Compounds of formula (I), which are useful in the curative and prophylactic treatment of a medical condition for which inhibition of a cyclic guanosine 3',5'- monophosphate phosphodiesterase (e.g. cGMP PDE5) and having utility in therapeutic areas such as erectile male dysfunction (MED) are disclosed, wherein R1, R2, R3, R4 and X are as described in the specification.