| 摘要 |
PROBLEM TO BE SOLVED: To obtain a new pyrazolopyrimidinone cGMPPDE5 inhibitor useful for the therapy of disorders concerning male erection function or the like as an inhibitor against a guanosine 3',5'-cyclic monophosphate phosphodiesterase. SOLUTION: This new compound is expressed by formula I or II (wherein, A is CH or N; R1 and R2 are each H, an aryl or the like; R3 is H or a lower alkyl; R4 is SO2NR12R13; R12 is R13 combine each with N and together form a 4-12 membered heterocyclic group having nitrogen atom), and is, e.g. 3- benzyl-6-[2-ethoxy-5-(4-methylpiperazin-1-ylsulfonyl)phenyl]-1-n-propy l-1,5-dihydro-4 H-pyrazolo[3,4-d]pyrimidin-4-one. The compound of formula I is obtained by the cyclization of a new intermediate compound of formula IV obtained from a compound of formula III as a starting substance.
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