1-Fluoro-3,5-dimethyl-benzene → 2,4-Dichloro-1-fluoro-3,5-dimethylbenzene
Reaction equation
[Cl:1][C:2]1[C:10]([C:11]#N)=[C:9]([Cl:13])[C:8]([F:14])=[CH:7][C:3]=1[C:4](Cl)=O.C(C1C(F)=C(C=C(F)C=1F)C(F)=O)#N.FC1C=C(C)C=C(C)C=1>>[Cl:1][C:2]1[C:10]([CH3:11])=[C:9]([Cl:13])[C:8]([F:14])=[CH:7][C:3]=1[CH3:4]Participants
Procedure
An alternative process for preparing the intermediate 2,4-dichloro-3-cyano-5-fluorobenzoyl chloride (European Patent Application 276 700), which can be converted into 3-cyano-2,4,5-trifluoro-benzoyl fluoride, starts with 5-fluoro-1,3-xylene: 5-fluoro-1,3-xylene is dichlorinated at the ring in the presence of a catalyst under ionic conditions to give 2,4-dichloro-5-fluoro-1,3-dimethylbenzene which is subsequently chlorinated in the side chains under radical conditions to give 2,4-dichloro-5-fluoro-3-dichloromethyl-1-trichloromethylbenzene. This is hydrolysed via the 2,4-dichloro-5-fluoro-3-dichloromethylbenzoic acid to give 2,4-dichloro-5-fluoro-3-formylbenzoic acid, which is subsequently converted into 2,4-dichloro-5-fluoro-3-N-hydroxyiminomethyl-benzoic acid. Treatment with thionyl chloride gives 2,4-dichloro-3-cyano-5-fluoro-benzoyl chloride which can then be converted into 3-cyano-2,4,5-trifluoro-benzoyl fluoride by chlorine-fluorine exchange.
Sources & evidence
- ORD record
- ord-075d135b21eb4420aa6f1a5c79470a2e
- Source dataset
- uspto-grants-2001_09
- Patent number
- US06288081B1
Reaction notes
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