Crystal structure of N-[(2S,5R)-4-oxo-2,3-diphenyl-1,3-thia-zinan-5-yl]acetamide 0.375-hydrate.

The asymmetric unit of the title compound, C18H18N2O2S.0.375H2O, has two independent organic mol-ecules (A and B) and 3/4 of a water mol-ecule distributed over three sites. In mol-ecule A, the 1,3-thia-zine ring is in a boat conformation, with the C atoms at the 2- and 5-positions out of the plane. The angle between the two phenyl rings is 51.70 (12)°. In mol-ecule B, the thia-zine ring is in a half-chair conformation, with the S atom forming the back of the half-chair. The angle between the two phenyl rings is 84.44 (14)°. The A mol-ecule features an intra-molecular N-H⋯O hydrogen bond, which closes an S(5) ring motif. In the crystal, the corresponding N-H grouping of the B mol-ecule participates in an inter-molecular hydrogen bond to the A mol-ecule. The A mol-ecule participates in a C-H⋯O inter-action back to the B mol-ecule, whilst the B mol-ecule features an intra-molecular C-H⋯O link, which generates an S(10) loop.