Patent attributes
The invention relates to a process for the preparation of a crystalline isomeric mixture of compounds of formulae (I) and (II) which process comprises the following steps: a) the slow addition of aluminium chloride, in portions, to a solution comprising 1,1,3-trimethyl-3-phenylindan and isobutyric acid halide in a suitable solvent at a reaction temperature of from −20° C. to 20° C., an isomeric mixture consisting of compounds of formulae (Ia) and (IIa) being obtained; b) enol chlorination of compounds (Ia) and (IIa), an isomeric mixture consisting of compounds of formulae (Ib) and (IIb) being obtained; c) hydrolysis of the chlorinated isomeric mixture from step b). The invention relates also to the preparation of the individual compounds (I) and (II).
