1-Methyl-4-[1-(1-phenylethylidene)-hydrazin-2-ylidene]-3,4-dihydro-1H-2λ6,1-benzothiazine-2,2-dione

In the title compound, C17H17N3O2S, the phenyl ring is oriented at dihedral angles of 8.5 (2) and 1.17 (14)°, respectively, to the C=N—N plane and the fused aromatic ring. The thiazine ring adopts an envelope conformation with the S atom at the flap. In the crystal, a weak C—H⋯O interaction connects the molecules, forming a helical chain along the a axis.

In the title compound, C 17 H 17 N 3 O 2 S, the phenyl ring is oriented at dihedral angles of 8.5 (2) and 1.17 (14) , respectively, to the C N-N plane and the fused aromatic ring. The thiazine ring adopts an envelope conformation with the S atom at the flap. In the crystal, a weak C-HÁ Á ÁO interaction connects the molecules, forming a helical chain along the a axis.
The product obtained was then recrystallized in ethylacetate under slow evaporation to obtain single crystals suitable for X-ray diffraction.

Refinement
All H atoms were positioned with idealized geometry with C-H = 0.93 Å for aromatic, 0.96 Å for methyl group and 0.97 Å for methylene and were refined using a riding model, with U iso (H) = 1.2U eq (C) for aromatic and methylene, and U iso (H) = 1.5U eq (C) for methyl carbon atoms. Two reflections (0 1 1) and (0 0 2) were omitted in the final refinement.

Computing details
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009   The molecular structure of the title compound, with 50% displacement ellipsoids for non-H atoms.   Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1 −0.0436 (