| abstract |
Described is a process for the preparation of citalopram, its enantiomers and its acid addition salts, wherein the compound of formula (IV) wherein X is O or S, R 1 and R 2 are each independently selected from hydrogen and C 1-6 alkyl or R 1 and R 2 together form a C 2-5 alkylene chain to form a spiro ring, R 3 is selected from hydrogen and C 1-6 alkyl, R 4 is selected from hydrogen, C 1-6 alkyl, carboxy or a precursor group thereof, or R 3 and R 4 together form a C 2-5 alkylene chain, forming a spiro ring, treating with a dehydrating agent or, when X is S, using a thermal cleavage of the thiazoline ring, or treating with a radical initiator such as peroxide, or with light to form citalopram base or its acid addition salt and then optionally may convert said base or acid addition salt into a pharmaceutically acceptable salt thereof. Also described are intermediates used in the process of preparing citalopram. |