Patent ID: 6455710
Filing Date: 2002-09-24
Classification: A61P,C07D

Abstract:
A process for the preparation of citalopram in which a compound of formula II wherein Z is iodo, bromo, chloro or CF3â€”(CF2)n, â€”SO2â€”Oâ€”, 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 purified and subsequently treated with an amide or an amide-like group forming agent selected from the compounds of Formulas (a), (b) or (c): where X is halogen or a group Oâ€”COâ€”Râ€², Hal is halogen, Y is O or S, W is O, N or S and R, Râ€², Râ€³ and Râ€²â€³ are each selected from the group consisting of hydrogen, alkyl, and optionally substituted aryl or aralkyl; the reaction mixture is then subjected to an acid/base wash or crystallisation and recrystallisation of citalopram in order to remove amides formed from the crude citalopram mixture; and the resulting citalopram product is optionally purified and isolated as the base or a pharmaceutically acceptable salt thereof.