Preparation of 3-arylacrylic acids and their derivatives

US5359122A · kind A · utility

Assignee

• BASF SE

Inventors

• Michael Huellmann · Heppenheim, DE
• Josef Gnad · Ludwigshafen, DE
• Rainer Becker · Bad Dürkheim, DE

Key dates

• Filing date: Feb 8, 1994
• Grant date: Oct 25, 1994
• Expiry date: Feb 8, 2014

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C67/46
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The preparation of 3-arylacrylic acids and their derivatives I ##STR1## where Ar is aryl which can additionally have substituents which do not react with ketene and are stable under the conditions of the reaction described below, and PA1 R.sup.1 is hydrogen, an alkali metal, an alkaline earth metal, ammonium or C.sub.1 -C.sub.20 -alkyl, comprises a first stage in which a dialkyl acetal of an aromatic aldehyde of the formula II ##STR2## where R.sup.2 is C.sub.1 -C.sub.4 -alkyl, is reacted with ketene of the formula CH.sub.2 .dbd.C.dbd.O in the presence of catalytic amounts of a protic or Lewis acid to give a 3-arylpropionic acid derivative of the formula III ##STR3## and a second stage in which this intermediate III is reacted in the presence of acid or base and, in the case where R.sup.1 is C.sub.1 -C.sub.20 -alkyl, additionally with a C.sub.1 -C.sub.20 -alkanol to give the final product I.