Process for preparing 1,5-benzothiazepine derivatives.

摘要

There is disclosed a process for preparing 1,5-benzothiazepine derivatives represented by the formula: wherein one of R<1> and R<2> is a lower alkyl group or halogen atom, and the other is hydrogen atom, R<3> is a lower alkyl group or a lower alkoxy group, which comprises subjecting a propionic acid compound represented by the formula (II): wherein R<1>, R<2> and R<3> have the same meanings as defined above, and R<4> represents hydrogen atom or an ester residue, to intramolecular ring closing reaction in the presence of a sulfonic acid compound represented by the formula (III): R<5>SO3H (III) wherein R<5> represents a lower alkyl group or a substituted or unsubstituted phenyl group.