Synthesis and crystal structure of an (N-protected amino)-β β-lactam derivative of 1,5-benzothiazepine

The title compound alpha-(N-protected amino)-beta-lactam (C36H33N2O5CIS), derivative of 1,5-benzothiazepine, was prepared by the reaction of 1,5-benzothiazepine 1 with (4R)-phenyloxazolidylacetyl chloride and characterized by X-ray diffraction analysis. The title compound crystallizes in orthorhombic system, space group P2(1)2(1)2(1) with a=12.293(2), b=26.026(5), c=10.146(2)Angstrom, V=3246.1Angstrom(3), Z=4, D-c=1.312 g/cm(3), M-r=641.15, F(000)=1344, mu=-0.228mm(-1). The final R=0.0597 and wR=0.1165 for 3226 observed reflections with I greater than or equal to 2sigma(I). The crystal structure shows that the 4-phenyloxazolidyl and phenyl attached to C(8) and C(9) are in cis positions, and no trans product was discovered. So the cyclization to beta-lactam is stereospecific.