Experimental

R factor = 0.067; wR factor = 0.201; data-to-parameter ratio = 13.7. In the title compound, C18H16ClN3O2S, the dihedral angle between the aromatic rings is 4.81 (2) and the alkyl chain takes on an extended conformation [N—C—C—C = 179.2 (4)]. The conformation of the thiazine ring is an envelope, with the S atom displaced by 0.805 (3) A ̊ from the mean plane of the other five atoms (r.m.s. deviation = 0.046 Å). The Cl atom is an axial conformation and is displaced by 1.761 (4) A ̊ from the thiazine ring plane. In the crystal, inversion dimers linked by pairs of C—H O interactions generate R2 2(20) loops and further C—H O hydrogen bonds link the dimers into (001) sheets. Weak aromatic – stacking interactions [centroid–centroid separa-tions = 3.870 (3) and 3.883 (3) Å] are also observed. Related literature For the synthesis and biological activity of the title compound and related materials, see: Shafiq et al. (2011a). For further synthetic details, see: Shafiq et al. (2011b)