3-Cyano-2,4,5-trifluorobenoxyl fluoride and intermediate products for the production thereof

US7268248B2 · kind B2 · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Albrecht Marhold · Leverkusen, DE
• Peter Wolfrum · Monheim, DE

Key dates

• Filing date: Dec 31, 2003
• Grant date: Sep 11, 2007
• Expiry date: Dec 31, 2023

Classification

• Technology area (CPC G): Physics
• CPC primary: G01C22/002
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The present invention relates to 3-cyano-2,4,5-trifluorobenzoyl fluoride and to intermediates for its preparation and to the process for the preparation of 3-cyano-2,4,5-trifluoro-benzoyl fluoride, which starts from 5-fluoro-1,3-xylene (VIII); which is bichlorinated in the ring in the presence of a catalyst under ionic conditions to give 2,4-dichloro-5-fluoro-1,3-dimethylbenzene (VII). The latter is chlorinated in the side chains under free-radical conditions to give 2,4-dichloro-5-fluoro-3-dichloromethyl-1-trichloromethylbenzene (VI). The latter is hydrolysed via 2,4-dichloro-5-fluoro-3-dichloromethylbenzoic acid (V), which can be isolated if necessary, to give 2,4-dichloro-5-fluoro-3-formyl-benzoic acid (IV), the aldehyde group of which is reacted to give 2,4-dichloro-5-fluoro-3-N-hydroxyiminomethyl-benzoic acid (III), from which, with simultaneous conversion of the carboxyl group into the chlorocarbonyl group, water is eliminated using an acid chloride to give the nitrile 2,4-dichloro-3-cyano-5-fluoro-benzoyl chloride (II). Finally, the nitrile is subjected to fluorine/chlorine exchange.