METHOD FOR THE PREPARATION OF PURE CITALOPRAM

摘要

The present invention relates to a process for the preparation and purification of citalopram (I) in which a compound of Formula (II) wherein Z is iodo, bromo, chloro or CF3-(CF2)n-SO2-O-, n being 0, 1, 2, 3, 4, 5, 6, 7 or 8, is subjected to a cyanide exchange reaction with a cyanide source; the resultant crude citalopram product is optionally subjected to some initial purification and subsequently treated with an amide or an amide-like group forming agent; the reaction mixture is then subjected to an acid/base wash and/or crystallisation and recrystallisation of citalopram in order to remove the amides formed from the crude citalopram mixture; and the resulting citalopram product is optionally further purified, worked up and isolated as the base or a pharmaceutically acceptable salt thereof.