3-(3-Chlorobenzoyl)-4-hydroxy-2H-1,2-benzothiazine 1,1-dioxide

In the title compound, C15H10ClNO4S, the heterocyclic thiazine ring adopts a half-chair conformation with the S and N atoms displaced by 0.476 (5) and 0.227 (5) Å, respectively, on opposite sides of the mean plane formed by the remaining ring atoms. The structure is stabilized by intermolecular N—H⋯O and C—H⋯O hydrogen bonds. In addition, intramolecular O—H⋯O and C—H⋯N interactions are also present.

In the title compound, C 15 H 10 ClNO 4 S, the heterocyclic thiazine ring adopts a half-chair conformation with the S and N atoms displaced by 0.476 (5) and 0.227 (5) Å , respectively, on opposite sides of the mean plane formed by the remaining ring atoms. The structure is stabilized by intermolecular N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds. In addition, intramolecular O-HÁ Á ÁO and C-HÁ Á ÁN interactions are also present.
The structure is stabilized by intermolecular hydrogen bonds of the types N-H···O and C-H···O. In addition, intramolecular interactions O3-H3O···O4 and C15-H15···N1 are also present consolidating the crystal packing; details are provided in Table 1.

Refinement
Though all the H atoms could be distinguished in the difference Fourier map, they were included at geometrically idealized positions and refined using a riding-model approximation with the following constraints: O-H, N-H and C-H distances were set to 0.82, 0.86 and 0.93 Å, respectively, and U iso (H) = 1.2U eq (parent atom). The final difference map was essentially featureless.
supplementary materials sup-2 Figures   Fig. 1. The title molecule with the displacement ellipsoids plotted at 30% probability level (Farrugia, 1997). Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 Rfactors(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.