PROCESS FOR THE PREPARATION OF BENZOTHIAZEPINES BY CYCLIZATION WITH PHOSPHONIC ACIDS

摘要

A process for the preparation of (2S,3S)-2,3-dihydro-3-hydroxy-2-(4- -methoxyphenyl)-1,5-benzothiazepin-4(5H)-one (compound I) by cyclization of an intermediate of formula (II) wherein R represents a C1-C3 alkyl and the asterisks identify the asymmetric carbon atoms; is described. Compound I is an intermediated useful in the synthesis of Diltiazem.