2-{[2-(1-Methyl-2,2-dioxo-3,4-dihydro-1H-2λ6,1-benzothiazin-4-ylidene)hydrazin-1-ylidene]methyl}phenol

In the title compound, C16H15N3O3S, the dihedral angle between the aromatic rings is 8.18 (11)° and the C=N—N=C torsion angle is 178.59 (14)°. The conformation of the thiazine ring is an envelope, with the S atom displaced by 0.8157 (18) Å from the mean plane of the other five atoms (r.m.s. deviation = 0.045 Å). An intramolecular O—H⋯N hydrogen bond closes an S(6) ring. In the crystal, weak C—H⋯O interactions link the molecules, with all three O atoms acting as acceptors.

In the title compound, C 16 H 15 N 3 O 3 S, the dihedral angle between the aromatic rings is 8.18 (11) and the C N-N C torsion angle is 178.59 (14) . The conformation of the thiazine ring is an envelope, with the S atom displaced by 0.8157 (18) Å from the mean plane of the other five atoms (r.m.s. deviation = 0.045 Å ). An intramolecular O-HÁ Á ÁN hydrogen bond closes an S(6) ring. In the crystal, weak C-HÁ Á ÁO interactions link the molecules, with all three O atoms acting as acceptors.
MS acknowledges Higher Education commission of Pakistan for supporting PhD studies and the provision of a grant to strengthen the Materials Chemistry Laboratory at GC University Lahore, Pakistan.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT5989). In the synthesis of title compound, 4-hydrazinylidene-1-methyl-3H-2λ 6 ,1-benzothiazine-2,2-dione was subjected to react with 2-hydroxy benzaldehyde according to literature procedure ((Shafiq et al. (2011)). The product obtained was then recrystallized in ethylacetate under slow evaporation to obtain single crystals suitable for X-ray diffraction.

Refinement
The O-bond H atom was located in a difference map and its position was freely refined. The C-bound H-atoms were placed in calculated positions (C-H = 0.93-0.97 Å) and refined as riding. The methyl group was allowed to rotate, but not to tip, to best fit the electron density. The constraint U iso (H) = 1.2U eq (C,O) or 1.5U eq (methyl C) was applied.

Figure 1
The molecular structure of (I), showing displacement ellipsoids at the 50% probability level. The hydrogen bond is shown as a double-dashed line.   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.