Crystal structures of three substituted 3-aryl-2-phenyl-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-ones.

Three ring-substituted 3-aryl analogs of 2-phenyl-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one, namely 3-(4-meth-oxy-phen-yl)-2-phenyl-4H-1,3-benzo-thia-zin-4-one, C21H17NO2S, (I), 2-phenyl-3-[4-(tri-fluoro-meth-yl)phen-yl]-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one toluene hemisolvate, C21H14F3NOS·0.5C7H8, (II), and 3-(3-bromo-phen-yl)-2-phenyl-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one toluene hemisolvate, C20H14BrNOS·0.5C7H8, (III), were synthesized and their crystal structures determined. The hemisolvates differ in that in (II), the asymmetric unit comprises two molecules of the benzo-thia-zinone compound and a toluene solvent mol-ecule, whereas in (III), the unit comprises one benzo-thia-zinone mol-ecule and a half-occupancy toluene solvent mol-ecule. All crystals are of racemic mixtures of the chiral 2-C atom of the thia-zine moiety, which in all structures has a screw-boat puckering, with the puckering amplitude values within the range 0.575-0.603†à . In all three structures, the benzene plane of the benzo-thia-zine system makes a dihedral angle in the range 78.60†(5) to 98.40†(5)° with the unsubstituted benzene plane and in the range 70.50†(1) to 121.00†(5)° with the substituted benzene plane. The CF3 substituent group in one of the mol-ecules of (II) shows positional disorder, with an occupancy ratio of 0.57†(3):0.43†(3). In the crystals of (I) and (II), weak inter-molecular C-H⋯O inter-actions are present, giving in (I), mol-ecules arranged in a plane parallel to (010), and in (II), chains along a. In addition, all three structures show weak C-H⋯π inter-actions involving various aromatic rings.