2,4-Dichloro-N-(2-methylphenyl)benzenesulfonamide

In the title compound, C13H11Cl2NO2S, the methyl-substituted aromatic ring is disordered over two positions [occupancy ratio 0.705 (5):0.295 (5)]. The dihedral angles between the two aromatic rings are 74.9 (1) and 71.0 (3)° in the two disorder components. The crystal structure features centrosymmetric dimers linked by pairs of N—H⋯O hydrogen bonds.

In the title compound, C 13 H 11 Cl 2 NO 2 S, the methyl-substituted aromatic ring is disordered over two positions [occupancy ratio 0.705 (5):0.295 (5)]. The dihedral angles between the two aromatic rings are 74.9 (1) and 71.0 (3) in the two disorder components. The crystal structure features centrosymmetric dimers linked by pairs of N-HÁ Á ÁO hydrogen bonds.

Related literature
For the preparation of the title compound, see: Savitha & Gowda (2006). For our studies of the effect of substituents on the structures of N-(aryl)arylsulfonamides, see: Gowda et al. (2008Gowda et al. ( , 2010a; For related structures, see: Gelbrich et al.
In the crystal structure, the pairs of intermolecular N-H···O hydrogen bonds (Table 1) link the molecules through inversion-related dimers into infinite chains running parallel to the c-axis. Part of the crystal structure is shown in Fig. 2.

Experimental
The solution of 1,3-dichlorobenzene (10 ml) in chloroform (40 ml) was treated dropwise with chlorosulfonic acid (25 ml) at 0 ° C. After the initial evolution of hydrogen chloride subsided, the reaction mixture was brought to room temperature and poured into crushed ice in a beaker. The chloroform layer was separated, washed with cold water and allowed to evaporate slowly. The residual 2,4-dichlorobenzenesulfonylchloride was treated with o-toluidine in the stoichiometric ratio and boiled for ten minutes. The reaction mixture was then cooled to room temperature and added to ice cold water (100 ml). The resultant solid 2,4-dichloro-N-(2-methylphenyl)benzenesulfonamide was filtered under suction and washed thoroughly with cold water. It was then recrystallized to constant melting point from dilute ethanol. The purity of the compound was checked and characterized by recording its infrared and NMR spectra (Savitha & Gowda, 2006).
Prism like colourless single crystals used in X-ray diffraction studies were grown in ethanolic solution by slow evaporation at room temperature.

Refinement
The H atom of the NH group was located in a difference map and its coordinates were refined with the N-H distance restrained to 0.86 (2) %A. The other H atoms were positioned with idealized geometry using a riding model with C-H = 0.93-0.96 Å. All H atoms were refined with isotropic displacement parameters set to 1.2 times of the U eq of the parent atom.
Atoms C7-C12 of the phenyl ring and C13 of the methyl group are disordered and were refined using a split model. The corresponding site-occupation factors were refined so that their sum was unity [0.705 (5) and 0.295 (5)]. The corresponding bond distances in the disordered groups were restrained to be equal. Fig. 1. Molecular structure of (I), showing the atom labelling scheme and displacement ellipsoids are drawn at the 50% probability level. Only the major occupied component is shown.