Patent ID: 8436191

Claim:
A process for preparing a compound of formula (I) where R 1 represents C 1 -C 6 -alkyl and R 2 represents C 1 -C 5 -fluoroalkyl that is optionally bromo- or chloro- substituted, wherein said process comprises reacting a compound of formula (II) where R 1 and R 2 are as defined above, with a fluorinating agent of formula (III) M + F − (III) where M + represents Li + , Na + , K + , Cs + , Alk 4 N + and Alk represents C 1 -C 4 -alkyl, and optionally in the presence of a phase transfer catalyst to give a compound of formula (IV) where R 1 and R 2 are as defined above, and further reacting a compound of formula (IV) with a chlorinating agent to give a compound of formula (I).