Patent ID: 7579500

Claim:
A method for preparing 2,5-dimethyiphenylacetic acid, characterized in that p-xylene is converted with chloroacetyl chloride in a Friedel-Crafts reaction into 2-chloro-1-(2,5-dimethylphenyl)ethanone, which is reacted with the compound of the formula (II) HO—CH 2 —X—CH 2 —OH (II) in which X is a direct single bond or selected from the group consisting of CH 2 , CHCH 3 , C(CH 3 ) 2 and C(C 2 H 5 ) 2 , to give the compound of the formula (III) in which X has the meaning indicated above; the compound of the formula (III) is then rearranged to give a mixture of the formulae (IV) and (V) in which X has the meanings indicated above, and the latter is then hydrolyzed to 2,5-dimethylphenylacetic acid.