Process for the preparation of a benzothiazepine

Abstract

Process for the preparation of a 1,5-benzothiazepine derivative, or a salt thereof, of formula 1 ##STR1## where R1 represents H, an alkyl group or an alkoxy group and R.sub.2 represents H or a halogen, in which process a propanoic acid derivative of formula 2 ##STR2## where R.sub.1 and R.sub.2 are as defined above and R.sub.3 represents H or an alkyl group is subjected to an intramolecular cyclisation reaction in a non-halogenated solvent in the presence of a carboxylic acid. Preferably, R.sub.2 is H and R.sub.1 is OCH.sub.3. Trichloroacetic acid is preferably used as .alpha.-chlorinated acid. The benzothiazepine obtained on cyclisation can be subjected to an alkylation reaction and/or an acylation reaction to obtain known pharmaceutical products, in particular diltiazem.

Dependencies are inferred from the claim text.