Methyl 2-(3-oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl)acetate

In the crystal structure of the title compound, C11H11NO3S, the molecules are linked by intermolecular C—H⋯O hydrogen-bond interactions. The heterocyclic thiazine ring adopts a conformation intermediate between twist and boat.

In the crystal structure of the title compound, C 11 H 11 NO 3 S, the molecules are linked by intermolecular C-HÁ Á ÁO hydrogen-bond interactions. The heterocyclic thiazine ring adopts a conformation intermediate between twist and boat.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT5472).
In the crystal structure of the title compound ( Fig. 1), the molecules exhibit C···H-O intermolecular H-bonds interactions ( Fig. 2). The heterocyclic thiazine ring adopt half-chair conformation with the S and N atoms displaced by 0.357 (5) and 0.304 (15) Å, respectively, on the opposite sides from the mean plane formed by the remaining ring atoms. The methyl acetate group, which is almost planar with the r. m.s deviaton of 0.042 (14) Å, is iclined at dihedral angle of 88.31 (9)° and 74.67 (9)° with respect to the thiazine and benzene ring respectively.
In the title compound ( Fig. 1), the bond distances and angles agree with the cortresponding bond distances and angles reported in related compounds [Saeed et al. 2010 andAouine et al. 2010].

Experimental
To 1,4-benzithiazin-3-one (0.25 g, 1.5 mmol), potassium carbonate (0.41 g, 3 mmol), in ketone (15 ml) was added methyl chloroacetate (0.32 g, 3 mmol). The mixture was heated to reflux for 48 h. The salts were removed by filtration and the filtrate concentrated under reduced pressure. The residue was separated by chromatography on a column of silica gel with dichloromethane/diethyl ether (9/1) as eluent. Crystals were isolated when the solvent was allowed to evaporate.