Patent ID: 6015906
Filing Date: 2000-01-18
Classification: C07D

Abstract:
A process for the preparation of asymmetric esters of 4-(nitrophenyl)dihydropyridines of general formula (I) ##STR6## wherein R.sub.1 is a nitro group at the 2 or 3 position; R.sub.2 and R.sub.3, which are different from each other, are a methyl, ethyl, isopropyl, 2-methoxyethyl or isobutyl group; R.sub.4 and R.sub.5 are methyl groups,by reacting a benzylidene derivative of general formula (II) ##STR7## wherein R.sub.1, R.sub.2 and R.sub.4 have the meanings defined above, with an enamine derivative of general formula (III) ##STR8## wherein R.sub.3 and R.sub.5 have the meanings defined above, chacterized in that said reaction is carried out in the presence of dimethylamine benzoate or p-anisate as the catalyst, said catalyst being present in an amount of 0.005-0.015 mole per mole of benzylidene derivative.