Patent ID: 7112686

Claim:
A process for the preparation of racemic citalopram free base or an acid addition salt thereof and R- or S-citalopram as the free base or an acid addition salt thereof from non-racemic citalopram comprising the steps of: i) precipitating citalopram as the free base or as an acid addition salt thereof from a solution of non-racemic citalopram, wherein the precipitated citalopram comprises racemic citalopram and the mother liquor comprises R- or S-citalopram; ii) separating the precipitate from the mother liquor; iia) if the precipitate is crystalline, optionally recrystallizing the precipitate one or more times to form racemic citalopram, and then optionally converting the precipitate into an acid addition salt thereof; iib) if the precipitate is not crystalline, optionally repeating the precipitation of step i) and the separation of step ii) until a crystalline precipitate is obtained, optionally recrystallizing the crystalline precipitate one or more times to form racemic citalopram, and then optionally converting the precipitate into an acid addition salt thereof; iii) optionally subjecting the mother liquor to further purification; iv) isolating R- or S-citalopram from the mother liquor and optionally converting the R- or S-citalopram into an acid addition salt thereof.