ClC1C(F)=CC(F)=C([N+:8]([O-:10])=[O:9])C=1.[Cl:13][C:14]1[C:19]([F:20])=[CH:18][C:17]([F:21])=[C:16]([Cl:22])[CH:15]=1>>[Cl:13][C:14]1[C:19]([F:20])=[CH:18][C:17]([F:21])=[C:16]([Cl:22])[C:15]=1[N+:8]([O-:10])=[O:9]A synthesis proceeding via four stages can be taken from EP 562 435. 2,4,5-Trichloronitrobenzene is first reacted with an alkali metal fluoride to give 5-chloro-2,4-difluoronitrobenzene. By means of chlorinating denitration the 5-chloro-2,4-difluoronitrobenzene can be converted to 1,3-dichloro-4,6-difluorobenzene. The 1,3-dichloro-4,6-difluorobenzene is nitrated to give 2,6-dichloro-3,5-difluoronitrobenzene. The desired 3,5-difluoroaniline can be prepared from the 2,6-dichloro-3,5-difluoronitrobenzene by reaction with hydrogen with elimination of hydrogen chloride and reduction of the nitro group.
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