申请人:Bayer Corporation
公开号:US06541675B2
公开(公告)日:2003-04-01
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.
本发明涉及3-氰基-2,4,5-三氟苯甲酰氟和其制备的中间体,以及制备3-氰基-2,4,5-三氟苯甲酰氟的过程,该过程从5-氟-1,3-二甲基苯(VIII)开始;在催化剂存在下,在离子条件下对其进行环中双氯化,得到2,4-二氯-5-氟-1,3-二甲基苯(VII)。然后在自由基条件下对其进行侧链氯化,得到2,4-二氯-5-氟-3-二氯甲基-1-三氯甲基苯(VI)。然后通过2,4-二氯-5-氟-3-二氯甲基苯甲酸(V)水解,如有必要,可以分离出该产物,得到2,4-二氯-5-氟-3-酰基苯甲酸(IV),其醛基反应形成2,4-二氯-5-氟-3-N-羟基亚甲基苯甲酸(III),通过同时将羧基转化为氯羰基,使用酸氯化物除去水,得到2,4-二氯-3-氰基-5-氟苯甲酰氯(II)。最后,对该腈进行氟/氯交换。