3-cyano-2,4,5-trifluoro-benzoyl fluoride and intermediate products for the production thereof
申请人:Bayer Aktiengesellschaft
公开号:US06229040B1
公开(公告)日:2001-05-08
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 hydrolyzed 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.
本发明涉及3-氰基-2,4,5-三氟苯甲酰氟及其制备中间体以及制备3-氰基-2,4,5-三氟苯甲酰氟的过程,该过程始于5-氟-1,3-二甲基苯(VIII),在离子条件下催化环中二氯化,得到2,4-二氯-5-氟-1,3-二甲基苯(VII)。后者在自由基条件下侧链氯化,得到2,4-二氯-5-氟-3-二氯甲基-1-三氯甲基苯(VI)。后者通过2,4-二氯-5-氟-3-二氯甲基苯甲酸(V)水解,必要时可以分离出,得到2,4-二氯-5-氟-3-甲酰基苯甲酸(IV),其醛基反应生成2,4-二氯-5-氟-3-N-羟基亚甲基苯甲酸(III),从中通过同时将羧基转化为氯羰基,使用酸氯化物消除水,得到腈2,4-二氯-3-氰基-5-氟苯甲酰氯(II)。最后,腈经过氟/氯交换。