Asymmetrical ester derivatives of 1,4-dihydropyridine-3,5-dicarboxylic acid

A compound which is an aminocrotonate compound of the formula:

• ##STR58## wherein R.sub.2 is selected from the group of substituents consisting of a C.sub.1 -C.sub.4 alkyl group, a benzyl group, a benzoyl group and a phenyl group which can be substituted by one or more C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkyl, cyano, nitro hydroxyl, or trifluoromethyl groups or by one or more halogen atoms.

A compound which is a ketoester compound of the formula:

• ##STR59## wherein R.sub.2 is selected from the group of substituents consisting of a C.sub.1 -C.sub.4 alkyl group, a benzyl group, a benzoyl group and a phenyl group which can be substituted by one or more C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkyl, cyano, nitro hydroxyl, or trifluoromethyl groups or by one or more halogen atoms.

A compound which is a diol compound of the formula:

• ##STR60## wherein R.sub.1 represents a C.sub.1 -C.sub.4 alkyl group, R.sub.3 and R.sub.4, which are identical or different, each represent a hydrogen atom, a nitro group or a chlorine atom, and wherein the two OH groups of the diol radical can be protected by a radical selected from the group consisting of methyl, ethyl, acetaniline, cyclopentylidene, cyclohexylidene, and benzylidene.