Patent ID: 8431718

Claim:
A process for preparing a compound of formula (I) in which R 1 is C 1 -C 6 -alkyl, R 2 is C 1 -C 5 -fluoroalkyl and X is fluorine or chlorine, comprising the stages (1) chlorinating a compound of formula (II) in which R 1 and R 2 have the meanings given above and R 3 is a linear or branched C 1-12 -alkyl group, in the presence of a chlorinating agent to give a compound of formula (III), in which R 1 , R 2 and R 3 have the meanings given above; (2a-i) fluorinating the compound of formula (III) in the presence of a fluorinating agent of formula (IV), in which M + is Li + , Na + , K + , Cs + or Alk 4 N + and Alk is C 1 -C 4 -alkyl, to give a compound of formula (V); (2a-ii) hydrolyzing a compound of the formula (V) to give a compound of formula (VIa); and (2a-iii) subsequent halogenation to give the compound of the formula (I), in which X is fluorine or chlorine; or (2b-i) hydrolyzing a compound of formula (III) to give a compound of formula (VIb); (2b-ii) subsequent halogenation of the a compound of formula (VIb) to give a compound of formula (VII); and (2b-iii) fluorinating a compound of formula (VII) in the presence of a fluorinating agent of the formula (IV), to give a compound of formula (I), in which X is fluorine