Crystal structures of rac -2,3-diphenyl-2,3,5,6-tetra-hydro-4 H -1,3-thia-zine-1,1,4-trione and N -[(2 S ,5 R )-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-4 H -1,3-thia-zine-1,1,4-trione, C 16 H 15 NO 3 S, in its racemic form, and N -[(2 S ,5 R )-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.