Crystal structures of rac-2,3-diphenyl-2,3,5,6-tetra-hydro-4H-1,3-thia-zine-1,1,4-trione and N-[(2S,5R)-1,1,4-trioxo-2,3-diphenyl-1,3-thia-zinan-5-yl]acet-amide.

The syntheses and crystal structures of two thia-zinone compounds, namely, rac-2,3-diphenyl-2,3,5,6-tetra-hydro-4H-1,3-thia-zine-1,1,4-trione, C(16)H(15)NO(3)S, in its racemic form, and N-[(2S,5R)-1,1,4-trioxo-2,3-diphenyl-1,3-thia-zinan-5-yl]acet-amide, C(18)H(18)N(2)O(4)S, in an enanti-opure form, are reported. The thia-zine rings in the two structures differ in their puckering, as a half-chair in the first and a boat pucker in the second. The extended structures for both compounds have only C-H⋯O-type inter-actions between symmetry-related mol-ecules, and exhibit no π-π stacking inter-actions in spite of each having two phenyl rings.