Preparation of isoxazole-3,4-dicarboxylic acid derivatives

US5264580A · kind A · utility

Assignee

• BASF SE

Inventors

• Volker Maywald · Ludwigshafen, DE
• Thomas Kuekenhoehner · Bischofswerda, DE
• Peter Muenster · Neulußheim, DE
• Stefan Stahl · Eppelheim, DE

Key dates

• Filing date: Mar 23, 1993
• Grant date: Nov 23, 1993
• Expiry date: Mar 23, 2013

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D261/18
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing isoxazole-3,4-dicarboxylic acid derivatives of the formula I ##STR1## where R.sup.1 is hydrogen, alkyl, cycloalkyl or phenyl, or a 5- to 6-membered heterocyclic radical, and the organic radicals can have substituents which are inert under the reaction conditions; PA1 R.sup.2 is hydrogen, alkyl, cycloalkyl, benzyl or C.sub.3 -C.sub.6 -alkenyl; PA1 A is NR.sup.3 R.sup.4 where R.sup.3 is hydrogen or an aliphatic or cycloaliphatic radical and R.sup.4 is an aliphatic or cycloaliphatic radical or unsubstituted or substituted phenyl, or R.sup.3 forms together with R.sup.4 a 4- to 7-membered alkylene chain which can be interrupted by oxygen, sulfur or N-methyl, or is OR.sup.5 where R.sup.5 is alkyl, cycloalkyl, benzyl or alkenyl; by deprotonation of a CH-acid compound of the formula II ##STR2## using a base and reacting with hydroximyl chlorides of the formula III ##STR3## wherein a magnesium alcoholate of the formula IV EQU Mg(OR.sup.6 ).sub.2 IV where R.sup.6 is an aliphatic or cycloaliphatic radical is used for the deprotonation.