Synthesis and crystal structure of racemic (R*,R*)-2,2'-(1,4-phenyl-ene)bis-(3-phenyl-2,3,5,6-tetra-hydro-4H-1,3-thia-zin-4-one).

In the racemic title compound, C26H24N2O2S2, one of the thia-zine rings shows a twisted boat conformation (Q = 0.743 Å, θ = 92.1°) and the other a half-chair puckering (Q = 0.669 Å, θ = 54.3°). The terminal phenyl rings are almost parallel to each other [dihedral angle 21.71 (10)°]. Both of these rings are orthogonal to the central phenyl ring, subtending a dihedral angle of about 78° in each case. The extended structure is consolidated by C-H⋯O and C-H⋯S hydrogen bonds as well as aromatic ring inter-actions of parallel-displaced and T-type. The mol-ecule has approximate C2 local symmetry but this is not carried over to its three-dimensional structure or the inter-molecular inter-actions. © Yennawar et al. 2021.