5-(PYRIDINYL)-1H-BENZIMIDAZOLES AND 1-HYDROXY-6- (PYRIDINYL)-1H-BENZIMIDAZOLES, THEIR PREPARATION AND USE AS CARDIOTONICS

摘要

2-R-5-(Py-Y)-1H-benzimidazole or pharmaceuticallyacceptable acid-addition salt thereof, useful as a cardiotonic, is prepared by reacting 4-(Py-Y)-1,2-benzenediamine with a tri-(lower-alkyl)ortho-(lower-alkanoate) of the formula R-C(OR1)3, where R is hydrogen or lower-alkyl, Y is a direct linkage or lower-alkylene having one or two carbon atoms, and Py is 4- or 3-pyridinyl or 4- or 3-pyridinyl having one or two lower-alkyl substituents, or with dimethylformamide dimethyl acetal or dimethylacetamide dimethyl acetal to produce said 2-R-5-(Py-Y)-1H-benzimidazole where R is methyl or ethyl respectively. The same compound where R is lower-alkyl is prepared in two steps by first reacting 4-(Py-Y)-1,2-benzenediamine with an alkanoylating agent providing alkanoyl of the formula < IMG > to produce N2-¢R'- C(=0)!-4-(Py-Y)-1,2-benzenediamine and heating the latter compound to produce said 2-R'-5-(Py-Y)-1H-benzimidazole, where R' is lower-alkyl. Also shown is 1-hydroxy-2-R-6-(Py- Y)-1H-benzimidazole or pharmaceutically-acceptable acidaddition salt thereof, useful as a cardiotonic and prepared by reacting 3-nitro-N-(RCO)-4-(Py-Y)-benzeneamine with hydrogen under catalytic hydrogen conditions.