Process for preparing 1,5-benzothiazepine derivatives

摘要

There is disclosed a process for preparing 1,5-benzothiazepine derivatives of the formula: <IMAGE> (I) wherein R1 is a lower alkyl group, or a salt thereof which comprises subjecting a propionate derivatives of the formula: <IMAGE> (II) wherein R2 is an ester residue and R1 is the same as defined above, to intramolecular cyclization in the presence of a sulfonic acid compound of the formula: R3SO3H(III) wherein R3 is a lower alkyl group or a substituted or unsubstituted phenyl group, in a non-halogenated organic solvent and, if desired, converting the product to a salt thereof.