| abstract |
The invention relates to a process for the preparation of highly pure 4-(3,4-dichloro-phenyl)-3,4-dihydro-1(2H)-naphthalene-1-one of formula (I), by reacting o-dichloro-benzene and α-naphthol in a solvent as medium in the presence of a Friedel-Crafts catalyst which comprises crystallizing the crude reaction product of formula (I) at least once from a polar solvent and at least once from an apolar solvent, whereby said crystallization steps can be carried out in optional order of succession, and whereby the amount of the by-product 4-(2,3-dichloro-phenyl)-3,4-dihydro-1(2H)-naphthalene-1-one of formula (II) is decreased below 1 %. The compound of formula (I) is a useful pharmaceutical intermediate. The advantage of the process is that the described compound is obtained in highly pure form. |