Patent ID: 6197953
Filing Date: 2001-03-06
Classification: C07C,C07D

Abstract:
In a process for preparing a (2S,3S)-1,5-benzothiazepine derivative of the formula (II): ##STR21##wherein ring A and ring B are independently a substituted or unsubstituted benzene ring, and R.sup.2 is a 2-(dimethylamino)ethyl group or a group of the formula: ##STR22##or a pharmaceutically acceptable salt thereof, the improvement comprising using as the starting material a (2R,3S)-isomer of trans-3-substituted glycidic acid ester compound of the formula (I): ##STR23##wherein ring A is a substituted or unsubstituted benzene ring, and R.sup.1 is an ester residue, which is obtained bypreparing a solution of the (2R,3S)-isomer (A) and the (2S,3R)-isomer (B) of the ester compound (I), both of which are optical isomers due to the asymmetric carbons at the 2- and 3-positions, and an ester compound (B') which is different from the (2S,3R)-isomer (B) only in the ester residue R.sup.1, crystallizing the (2R,3S)-isomer (A) from the solution up to the extent that the (2R,3S)-isomer (A) is crystallized without the precipitation of the (2S,3R)-isomer (B) due to the presence of the ester compound (B') though the (2S,3R)-isomer (B) would precipitate if the ester compound (B') were not present, andisolating the crystals of the (2R,3S)-isomer (A).