Process for the Preparation of O-Desmethyl Venlafaxine and Intermediate for Use Therein

摘要

The present invention relates to a compound of formula A, wherein R is alkyl.;;Compound A may be used as an intermediate in the preparation of O-desmethyl venlafaxine or a salt thereof, and the present invention provides such a preparation, as well as a process for preparing the compound of formula A.

主权项

1. A process for preparing a compound of formula A,wherein R is an alkyl group, the process comprising:
a) esterifying (4-benzyloxy-phenyl)-acetic acid of formula Ito form a (4-benzyloxy-phenyl)-acetic acid alkyl ester of formula II; b) reacting the (4-benzyloxy-phenyl)-acetic acid alkyl ester of formula II with paraformaldehyde in the presence of an inorganic base and a phase transfer catalyst to form a 2-(4-benzyloxy-phenyl)-acrylic acid alkyl ester of formula III; and c) reacting the 2-(4-benzyloxy-phenyl)-acrylic acid alkyl ester of formula III with dimethylamine in the presence of a Lewis acid catalyst to form the compound of formula A.