4-Chloro-N-(2,5-dimethylphenyl)-2-methylbenzenesulfonamide

The asymmetric unit of the title compound, C15H16ClNO2S, contains three independent moleules. The conformation of the N—H bonds are anti to the ortho-methyl groups of the sulfonyl benzene rings in all the molecules. The sulfonyl and the aniline benzene rings are tilted relative to each other by 43.0 (2), 37.0 (2) and by 46.0 (1)° in the three molecules. In the crystal, intermolecular N—H⋯O hydrogen bonds link each of the molecules into centrosymmetric dimers.

The asymmetric unit of the title compound, C 15 H 16 ClNO 2 S, contains three independent moleules. The conformation of the N-H bonds are anti to the ortho-methyl groups of the sulfonyl benzene rings in all the molecules. The sulfonyl and the aniline benzene rings are tilted relative to each other by 43.0 (2), 37.0 (2) and by 46.0 (1) in the three molecules. In the crystal, intermolecular N-HÁ Á ÁO hydrogen bonds link each of the molecules into centrosymmetric dimers.
The asymmetric unit of (I) contains three independent moleules. The conformation of the N-H bonds are anti to the ortho-methyl groups in the sulfonyl benzene rings of all the molecules. The other bond parameters in (I) are similar to those observed in (II) and other aryl sulfonamides (Perlovich et al., 2006;Gelbrich et al., 2007).
In the crystal, the intermolecular N-H···O hydrogen bonds (Table 1) link the molecules to centrosymmetric dimers. Part of the crystal structure is shown in Fig. 2.

Experimental
The solution of m-chlorotoluene (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-methyl-4-chlorobenzenesulfonylchloride was treated with 2,5-dimethylaniline 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 cc). The resultant solid 4-chloro-2-methyl-N-(2,5-dimethylphenyl)-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.

supplementary materials sup-2 Refinement
The H atoms of the NH groups were located in a difference map and their 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 the aromatic C-H = 0.93Å and methyl C-H = 0.96 Å. All H atoms were refined with isotropic displacement parameters. The U iso (H) values were set at 1.2U eq (C-aromatic, N) and 1.5U eq (C-methyl). Fig. 1. Molecular structure of the title compound, showing the atom labelling scheme and displacement ellipsoids are drawn at the 50% probability level.