Method for producing 2-chloromethylphenyl acetic acid derivatives

The invention relates to a method for producing 2-chloromethylphenyl acetic acid derivatives of formula (I), in which X represents C1-C4 alkoxy or methylamino, by cleaving the ether bonds in compounds of formula (II), in which R represents C1-C4 alkyl, C1-C4 alkoxy, C1-C2 alkyl halide, C1-C4 alkylcarbonyl, C1-C4 alkylcarbonyloxy, halogen, nitro or cyano, and X has the above-mentioned meaning. The inventive method is characterized in that the transformation takes place in the presence of hydrogen chloride and of an inert solvent, and in that a catalyst selected from the group comprised of: iron, indium or halogenides, oxides or triflates thereof is added to the reaction mixture.