Crystal and molecular structure of trans-(±)-3-acetoxy-2- (4methoxyphenyl)-4-oxo-2,3,4,5-tetrahydro-1,5-benzothiazepine-1-oxide

The title compound is a structurally related isomer of diltiazem, a well known drug. This compound (C18H17NO5S) crystallizes in the space group P21/n with a = 13.803(4), b = 7.704(3), c = 16.093(3) à , β= 105.37(2)°, Z = 4, V = 1650.1(9) à ,3. The least-squares refinement gave residual index R = 0.067 for 2831 observed reflections. The distorted seven-membered ring in the molecule shows twist-boat conformation. Hydrogen bonds in which the amide group at one molecule and a carbonyl group in the adjacent molecule are involved to form centrosymmetric dimers in the crystal. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA