Patent ID: 8183401

Claim:
A method for preparing a compound of formula (I) wherein each of R 1 , R 2 , R 3 , R 4 , independently, is hydrogen, halogen or C 1 -C 6 alkyl, the method comprising: reacting a compound of formula (II) wherein R 1 , R 2 , R 3 , R 4 are as defined above and R is alkylene, with a deprotonating agent and a compound of the formula R 5 SO 2 X wherein R 5 is C 1 -C 5 alkyl and X is halogen so as to obtain a compound of formula (III) wherein R 1 , R 2 , R 3 , R 4 , R 5 are as defined above; and reacting the compound of formula (III) with a base.