2,4-Dichloro-N-(2,5-dimethylphenyl)benzenesulfonamide

The asymmetric unit of the title compound, C14H13Cl2NO2S, contains three independent moleules. The torsion angles of the C—SO2—NH—C segments in the three molecules are 67.5 (2), 83.4 (2) and −77.5 (2)°. The two aromatic rings are tilted relative to each other by 68.8 (1), 64.1 (1) and 68.5 (1)°. The crystal structure features dimers linked by pairs of N—H⋯O hydrogen bonds.

The asymmetric unit of the title compound, C 14 H 13 Cl 2 NO 2 S, contains three independent moleules. The torsion angles of the C-SO2-NH-C segments in the three molecules are 67.5 (2), 83.4 (2) and À77.5 (2) . The two aromatic rings are tilted relative to each other by 68.8 (1), 64.1 (1) and 68.5 (1) . The crystal structure features dimers linked by pairs of N-HÁ Á ÁO hydrogen bonds.
VZR thanks the University Grants Commission, Government of India, New Delhi, for the award of a RFSMS fellowship.
In the crystal structure, the pairs of intermolecular N-H···O hydrogen bonds (Table 1) link the molecules into dimers.
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 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 ml).
The resultant solid 2,4-dichloro-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 light pink single crystals used in X-ray diffraction studies were grown in ethanolic solution by slow evaporation at room temperature.

Refinement
The H atoms of the NH groups were located in a difference map and 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. Their isotropic displacement parameters were set to 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. 2,4-Dichloro-N-(2,5-dimethylphenyl)benzenesulfonamide