Process for the preparation of 1,4-dihydropyridinedicarboxylic esters

US4600778A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Werner Teller · Wuppertal, DE
• Wolfgang Koebernick · Wuppertal, DE
• Arthur Haaf · Wuppertal, DE
• Paul Naab · Bad Reichenhall, DE
• Michael Preiss · Leinfelden, DE

Key dates

• Filing date: Mar 20, 1984
• Grant date: Jul 15, 1986
• Expiry date: Mar 20, 2004

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D211/90
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

In the preparation of a 1,4-dihydropyridine of the formula ##STR1## in which R is a phenyl radical which is optionally substituted once or twice by nitro and/or chlorine, PA1 R.sub.1 is a C.sub.1 -C.sub.4 -alkyl radical which is optionally substituted by a C.sub.1 -C.sub.4 -alkoxy group, and PA1 R.sub.2 is a C.sub.1 -C.sub.12 -alkyl radical which is optionally substituted by a C.sub.1 -C.sub.4 -alkoxy group, a trifluoromethyl group or the radical (C.sub.6 H.sub.5 CH.sub.2) (CH.sub.3)N, by preparing an ylidene compound of the formula ##STR2## and reacting such ylidene compound with an enamine compound of the formula ##STR3## the improvement which comprises preparing the ylidene compound by reaction of a ketocarboxylic ester of the formula ##STR4## with an aldehyde of the formula RCHO, in a solvent in the presence of a catalytic amount of any acetate salt of an amine, at a temperature from about -10.degree. C. up to 100.degree. C. The products symmetrical or unsymmetrical, are produced in high yield and purity.