Pyrazolopyridylpyridazinone derivatives and process for the preparation thereof

摘要

Novel pyrazolopyridylpyridazinone derivatives characterized by being represented by general formula (1) and pharmacologically acceptable salts thereof, which exhibit a phosphodiesterase inhibiting activity and have a selective potent bronchodilating effect on the respiratory tract: a process for the preparation of them: and bronchodilators containing the same as the activity ingredient: wherein R<1> is C1-C4 lower alkyl or C3-C6 cycloalkyl: and R<2>, R<3>, R<4> and R<5> are each independently hydrogen, C1-C4 lower alkyl or phenyl, or alternatively R<3> and R<5> may be united to form a double bond.