Process for the preparation of racemic citalopram diol and/or S- or R-citalopram diols and the use of such diols for the preparation of racemic citalopram, R-citalopram and/or S-citalopram
US7390913B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 2003 |
| Grant date | Jun 24, 2008 |
| Priority date | — |
| Expiry date | Dec 5, 2024 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C253/34
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
In the following, citalopram diol means 4-(4-(dimethylamino)-1-(4-fluorophenyl)-1-hydroxybutyl)-3-(hydroxymethyl)-benzonitrile, as free base and/or acid addition salt. The invention relates to a process for the preparation of racemic citalopram diol and/or R- or S-citalopram diol, comprising the separation of a non-racemic mixture of R- and S-citalopram diol with more than 50% of one of the enantiomers into a fraction being enriched with S- or R-citalopram diol and a fraction comprising RS-citalopram diol wherein the ratio of R-citalopram diol:S-citalopram diol is equal to 1:1 or closer to 1:1 than in the initial mixture. The method is characterized in that (i) RS-citalopram diol is precipitated from a solution of the initial non-racemic mixture, or R- or S-citalopram diol is dissolved into a solvent from the initial non-racemic mixture, leaving a residue of RS-citalopram diol, and in that (ii) the residue/precipitate formed is separated from the final solution phase, followed by optional steps of repetition, recrystallisation, purification, isolation and conversion between free base and salts. The invention also relates to a process for the preparation of RS-citalopram, S-citalopr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.