NAPHTHYRIDINE DERIVATIVES AND PROCESS FOR THE PREPARATION THEREOF

摘要

Naphthyridine derivatives represented by general formula [I] or pharmacologically acceptable salts thereof; and a process for the preparation thereof (wherein A is substituted or unsubstituted pyridine ring or a substituted or unsubstituted dihydropyridine ring; B is a benzene ring having two to four substitutents which may be the same or different from each other and are selected from among optionally protected hydroxyl, optionally substituted lower alkyl, optionally substituted lower alkoxy and halogeno, or a benzene ring having one or two lower alkylenedioxy groups; R<1> is hydrogen, optionally substituted aryl, optionally substituted lower alkyl, a substituted or unsubstituted heterocyclic group, or optionally substituted amino; and R<2> is hydrogen or an ester residue). The above compounds are useful as preventive and therapeutic agents for circulatory diseases by virtue of their excellent PDE V inhibiting effects.