[2-(2,5-Dichlorobenzyl)-4-hydroxy-1,1-dioxo-2H-1,2-benzothiazin-3-yl](phenyl)methanone

In the title molecule, C22H15Cl2NO4S, the heterocyclic thiazine ring adopts a half-chair conformation, with the S and N atoms displaced by 0.343 (5) and 0.402 (5) Å, respectively, on opposite sides of the mean plane formed by the remaining ring atoms. The molecular structure is consolidated by an intramolecular O—H⋯O hydrogen bond, which generates an S(?) ring. In the crystal, the molecules are linked by C—H⋯O interactions into [010] chains.

In the title molecule, C 22 H 15 Cl 2 NO 4 S, the heterocyclic thiazine ring adopts a half-chair conformation, with the S and N atoms displaced by 0.343 (5) and 0.402 (5) Å , respectively, on opposite sides of the mean plane formed by the remaining ring atoms. The molecular structure is consolidated by an intramolecular O-HÁ Á ÁO hydrogen bond, which generates an S(?) ring. In the crystal, the molecules are linked by C-HÁ Á ÁO interactions into [010] chains.
The bond distances and angles in the title compound ( Fig. 1) agree well with the corresponding bond distances and angles reported for structures of closely related compounds (Ahmad et al., 2011;Aslam et al., 2012). The heterocyclic thiazine ring adopts a half chair conformation with atoms N1 and S1 displaced by 0.402 (5)Å and 0.343 (5)Å, respectively, on the opposite sides from the mean plane formed by the remaining ring atoms. The dihedral angle between the mean planes of benzene rings C1-C6 and C17-C22 is 31.17 (7)° while the mean planes of the benzene rings C1-C6 and C10-C15 are oriented at 35.09 (9)° with respect to each other. The molecular structure of the title compound is stabilized by intramolecular interactions O3-H3O···O4, C11-H11···N1 and C16-H16A···O2, etc, while the crystal packing is consolidated by C3-H3···O4 i intermolecular nonclassical hydrogen bonds resulting in chains of molecules lying along the b-axis ( Fig. 2 and Table 1). Symmetry code: (i) x, y+1, z.

Refinement
The H atoms bonded to C and O atoms were positioned geometrically and refined using a riding model, with O-H = 0.84Å and C-H = 0.95Å and 0.99Å, respectively, for aryl and methylene type H-atoms. The U iso (H) were allowed at 1.2U eq (parent atom). program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figure 1
The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 25% probability level. The H atoms are presented as small spheres of arbitrary radius.    where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.33 e Å −3 Δρ min = −0.44 e Å −3

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. 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.