| 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 <IMG> 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 C1-5 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 rink 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. |