Crystal structures of the sulfones of 2,3-diphenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one and 2,3-diphenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-one

The title sulfones, 2,3-diphenyl-2,3-di-hydro-4H-1,3-benzo-thia-zine-1,1,4-trione, C20H15NO3S, and 2,3-diphenyl-2,3-di-hydro-4H-pyrido[3,2-e][1,3]thia-zine-1,1,4-trione, C19H14N2O3S, crystallize in space group P21/n with two mol-ecules in each of the asymmetric units and have almost identical unit cells and extended structures. In both structures, the thia-zine rings exhibit a screw-boat pucker. The inter-molecular inter-actions observed are C-H⋯O-type hydrogen bonds and parallel partial π-π stacking between the fused aromatic rings (benzo- or pyrido-) of the core of the mol-ecules within each asymmetric unit, and also connecting to mol-ecules with translational periodicity in the a-axis direction in what can be described as columns (two per asymmetric unit) of stacked mol-ecules with alternating chirality. The pendant phenyl groups of both mol-ecules do not participate in aromatic ring inter-actions.