2-[2-(3-Methoxyphenyl)-2-oxoethyl]-1,2-benzisothiazol-3(2H)-one 1,1-dioxide

In the title compound, C16H13NO5S, the benzothiazole unit is essentially planar [maximum deviation = 0.0501 (10) Å for the S atom] and is oriented at a dihedral angle of 67.85 (5)° with respect to the methoxy-substituted benzene ring. The mean plane of the methoxy group is oriented at 14.3 (3)° with respect to the benzene ring to which it is attached. In the crystal structure, weak C—H⋯O hydrogen bonds form macrocyclic rings with R 2 2(10) and R 2 2(12) motifs.

In the title compound, C 16 H 13 NO 5 S, the benzothiazole unit is essentially planar [maximum deviation = 0.0501 (10) Å for the S atom] and is oriented at a dihedral angle of 67.85 (5) with respect to the methoxy-substituted benzene ring. The mean plane of the methoxy group is oriented at 14.3 (3) with respect to the benzene ring to which it is attached. In the crystal structure, weak C-HÁ Á ÁO hydrogen bonds form macrocyclic rings with R 2 2 (10) and R 2 2 (12) motifs.
The structure is devoid of any classical hydrogen bonds. However, non-classical hydrogen bonding interactions of the type C-H···O are present in the crystal structure resulting in ten and twelve membered macrocyclic rings in R 2 2 (10) and R 2 2 (12) motifs (Bernstein et al., 1995) ( Fig. 2 and Table 1).
Experimental 3-Methoxy phenacyl bromide (5.49 g, 0.024 mol) was slowly added to a suspension of sodium saccharine (5 g, 0.024 mol) in dimethylformamide (15 ml) and the mixture was stirred at 383 K for 3.0 hours under anhydrous conditions. On completion of reaction (indicated by tlc), the mixture was poured on crushed ice and the precipitates formed were filtered and washed with an excess of distilled water and cold ethanol respectively. Crystals suitable for diffraction were grown from a solution of (I) in chloroform-methanol (3:1).

Refinement
All H atoms were located from the difference Fourier maps and were included in the refinements at geometrically idealized positions with C-H distances = 0.95, 0.98 and 0.99 Å for aryl, methyl and methylene H atoms, respectively, and U iso = 1.2 times U eq of the C atoms to which they were bonded. The final difference map was free of chemically significant features. Fig. 1. ORTEP-3 (Farrugia, 1997) drawing of (I) with displacement ellipsoids plotted at 50% probability level.

Special details
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.