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

The asymmetric unit of the title compound, C(18)H(18)N(2)O(2)S.0.375H(2)O, has two independent organic mol­ecules (A and B) and 3/4 of a water mol­ecule distributed over three sites. In mol­ecule A, the 1,3-thia­zine 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 mol­ecule B, the thia­zine 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 mol­ecule features an intra­molecular N—H⋯O hydrogen bond, which closes an S(5) ring motif. In the crystal, the corresponding N—H grouping of the B mol­ecule participates in an inter­molecular hydrogen bond to the A mol­ecule. The A mol­ecule participates in a C—H⋯O inter­action back to the B mol­ecule, whilst the B mol­ecule features an intra­molecular C—H⋯O link, which generates an S(10) loop.