Absolute Conformation and Configuration of (2S, 3S)-3-Acetoxy-5-(dimethylaminoethyl)-2-(4-methoxyphenyl)-2,3-dihydro-1,5-benzothiazepin-4(5H)-one Chloride (Dilthiazem Hydrochloride)
Resolution of racemic cis-3-(2-aminophenylthio)-2-hydroxy-3-(4-methoxyphenyl) propionic acid (2) via the cinchonidine salt 3, and brucine salt 4, isolation of the calcium salts (+)- and (−)-5, as well as their cyclization to enantiomeric 1,5-benzothiazepines (+)- and (−)-1, are described. X-Ray single-crystal analysis reveals (2S, 3S) absoluteconfiguration of (+)-1 on the basis of tentative comparison of CD