Process for the removal of desmethyl citalopram from a citalopram product

摘要

The present invention relates to a process for removing desmethylcitalopram having the formula IMAGE from a crude product containing citalopram having the formula IMAGE which process comprises subjecting the crude citalopram product containing the desmethylcitalopram impurity to a preliminary purification, where appropriate, and subsequently treating the crude product with an agent which forms an amide or an amide-like group, after which the reaction mixture is subjected to an acid/base wash and/or crystallization and recrystallization of the citalopram for the purpose of removing the amides which have been formed in the crude citalopram mixture; and the resulting citalopram product is purified further, where appropriate, and worked-up and isolated as the base or a pharmaceutically acceptable salt thereof.