Crystal structures of two 2,3-diaryl-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-ones

The syntheses and crystal structures of 2,3-bis-[3-(tri-fluoro-meth-yl)phen-yl]-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one (di-m-CF₃; C₂₂H₁₃F₆NOS) (1) and 2,3-bis-(4-methyl-phen-yl)-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one (di-p-CH₃; C₂₂H₁₉NOS) (2) are reported. Each structure is racemic: the asymmetric unit of 2 consists of two mol-ecules. In both 1 and 2, the six-membered 1,3-thia-zine ring is close to an envelope conformation with the chiral C atom forming the flap. In 1, the 2-aryl group is pseudo-equatorial, while in 2 it is pseudo-axial. In 1, the pendant aryl rings form a V shape with an inter-centroid distance of 3.938 (3) Å and an acute dihedral angle of 48.3 (2)° between them. Both CF₃ groups are disordered over two orientations in 0.687 (19):0.313 (19) and 0.667 (16):0.33 (16) ratios. In each of the independent mol-ecules of 2, the aryl rings are almost orthogonal to each other [dihedral angles = 85.50 (12) and 86.07 (11)°]. In both structures, the chiral C atom and the O atoms participate in C-H⋯O-type hydrogen bonding between symmetry-related mol-ecules of 1 or the independent enanti-omers in 2, forming chains along the c-axis direction in 1 and the b-axis direction in 2. Additionally, in 1, π-π contacts of both face-to-face and edge-to-face type, as well as π-H⋯O and π-H⋯F inter-actions are observed. In 2, a racemic mixture of mol-ecules forms layers in the ac plane linked by weak π-π and C-H⋯π inter-actions.