the following biotransformation steps occurred : hydroxylation of the isobutyl moiety , dehydrogenation of the 1,4-dihydropyridine system , oxidative ester cleavage , hydroxylation of one of the methyl groups in 2- or 6-position and subsequent oxidation to the carboxylic acid , oxidation of one of the methyl groups of the isobutyl moiety to the carboxyl group reduction of the aromatic nitro group ( minor biotransformation reaction ) and glucuronidation as phase ii reaction .
C0014898
ester
C0007066
carboxylic acid