N-Benzyl-4-hydroxy-2-methyl-1,1-dioxo-2H-1λ6,2-benzothiazine-3-carboxamide

In the title molecule, C17H16N2O4S, the heterocyclic thiazine ring adopts a half-chair conformation, with the S and N atoms displaced by 0.546 (4) and 0.281 (4) Å, respectively, on opposite sides of the mean plane formed by the remaining ring atoms. The molecular structure is stabilized by an intramolecular O—H⋯O hydrogen bond. The two aromatic rings are inclined to one another by 42.32 (11)°. In the crystal, molecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers. The dimers are linked via a series of C—H⋯O interactions, leading to the formation of a three-dimensional network.

In the title molecule, C 17 H 16 N 2 O 4 S, the heterocyclic thiazine ring adopts a half-chair conformation, with the S and N atoms displaced by 0.546 (4) and 0.281 (4) Å , respectively, on opposite sides of the mean plane formed by the remaining ring atoms. The molecular structure is stabilized by an intramolecular O-HÁ Á ÁO hydrogen bond. The two aromatic rings are inclined to one another by 42.32 (11) . In the crystal, molecules are linked by pairs of N-HÁ Á ÁO hydrogen bonds, forming inversion dimers. The dimers are linked via a series of C-HÁ Á ÁO interactions, leading to the formation of a threedimensional network.
supplementary materials Acta Cryst. (2012) 1972). Benzothiazine based derivatives have also shown activities for the treatment of asthmatic therapy (Lazzeri et al., 2001). In continuation of our interest in the synthesis and crystal structures of 1,2-benzothiazine derivatives (Siddiqui et al., 2008;2009) we report herein on the crystal structure of the title compound.
The bond distances and angles in the title compound ( Fig. 1) agree very well with the corresponding bond distances and angles reported for closely related compounds (Siddiqui et al., 2008;2009). The heterocyclic thiazine ring adopts a half chair conformation with atoms S1 and N1 displaced by 0.546 (4) and 0.281 (4) Å, respectively, on the opposite sides from the mean plane formed by the remaining ring atoms. The molecular structure is stabilized by an intramolecular O3 -H3O···O4 hydrogen bond (Table 1). The aromatic rings [C1-C6 and C12-C17] are inclined to one another by 42.32 (11)°.
In the crystal, molecules are linked by a pair of N-H···O hydrogen bonds to form inversion dimers. The dimers are linked via a series of C-H···O interactions leading to the formation of a three-dimensional network. (Fig. 2 and Table 1).

Experimental
For the synthesis of the title compound, 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylic acid methyl ester 1,1 dioxide and benzyllamine were used as the starting materials following a procedure reported earlier (Siddiqui et al., 2008). Crystals of the title compound, suitable for the X-ray crystallographic study, were grown from a mixture of ethyl acetate and methanol (1:1) at room temperature [M.p. = 466 -467 K].

Refinement
All H atoms were positioned geometrically and refined using a riding model,     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.