Method for the preparation of citalopram
US6365747B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 1, 2001 |
| Grant date | Apr 2, 2002 |
| Priority date | — |
| Expiry date | Jun 1, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D413/04
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The present invention relates to a method for the preparation of citalopram or any of its enantiomers and acid addition salts thereof comprising treatment of a compound of formula (IV), wherein X is O or S; R1-R2 are each independently selected from hydrogen and C1-6 alkyl, or R1 and R2 together form a C2-5 alkylene chain thereby forming a spiro-ring; R3 is selected from hydrogen and C1-6 alkyl, R4 is selected from hydrogen, C1-6 alkyl, a carboxy group or a precursor group therefore, or R3 and R4 together form a C2-5 alkylene chain thereby forming a spiro-ring, with a dehydration agent or alternatively where X is S, thermally cleavage of the thiazoline ring, or treatment in presence of a radical initiator, to form citalopram. The invention also relates to intermediates used in the new process for the preparation of citalopram, as well as citalopram prepared according to the new process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.