PYRAZOLOPYRIDINE-4-YL PYRIDAZINONE DERIVATIVE AND ADDITION SALT THEREOF, AND PDE INHIBITOR COMPRISING THE DERIVATIVE OR SALT AS ACTIVE INGREDIENT

摘要

[PROBLEMS] To provide a novel pyrazolopyridine-4-yl pyridazinone derivative which has a phosphodiesterase inhibitory activity and is useful as a therapeutic agent. [MEANS FOR SOLVING PROBLEMS] A pyrazolopyridine-4-yl pyridazinone derivative represented by the general formula (1) (e.g., 6-(2-ethyl-7-methoxy-pyarzolo[1,5-a]pyridine-4-yl)-5-methyl-4,5-dihydro-3(2H)-pyridazinone).