3,5-bis-(Trifluoromethyl)-benzoyl chloride preparation in high yield in 4 stages from readily available 3,5-dimethyl-benzoic acid, for use as intermediate for drugs, pesticides or photoresistant

摘要

Preparation of 3,5-bis-(trifluoromethyl)-benzoyl chlorides (I) involves converting a 3,5-dimethyl-benzoic acid (V) into the acid chloride (IV), subjecting the side-chains to radical chlorination, fluorinating with anhydrous hydrogen fluoride and/or antimony pentafluoride to give a 3,5-bis-(trifluoromethyl)-benzoyl fluoride and reacting with silicon tetrachloride in presence of another Lewis acid. Preparation of 3,5-bis-(trifluoromethyl)-benzoyl chlorides of formula (I) involves: (1) converting a 3,5-dimethyl-benzoic acid of formula (V) into the corresponding acid chloride of formula (IV); (2) subjecting the side-chains to complete radical chlorination to give a 3,5-bis-(trichloromethyl)-benzoyl chloride of formula (III); (3) fluorinating with anhydrous hydrogen fluoride and/or antimony pentafluoride to give a 3,5-bis-(trifluoromethyl)-benzoyl fluoride of formula (II); and (4) reacting with silicon tetrachloride in presence of another Lewis acid. [Image] X : H, F or Cl. Independent claims are included for the intermediates (III; X = F or Cl) and (IV; X = F or Cl) as new compounds.