2,4-Dichloro-N-(3,4-dimethylphenyl)benzenesulfonamide

In the title compound, C14H13Cl2NO2S, the C—SO2—NH—C torsion angle is −60.84 (18). The sulfonyl and the aniline benzene rings are tilted relative to each other by 66.4 (1)°. The crystal structure features inversion-related dimers linked by pairs of N—H⋯O hydrogen bonds.

In the title compound, C 14 H 13 Cl 2 NO 2 S, the C-SO 2 -NH-C torsion angle is À60.84 (18). The sulfonyl and the aniline benzene rings are tilted relative to each other by 66.4 (1) . The crystal structure features inversion-related dimers linked by pairs of N-HÁ Á ÁO hydrogen bonds.
In (I), the N-H bond in the C-SO 2 -NH-C segment is syn to the meta-methyl group in the anilino benzene ring and orients itself towards the ortho-chloro group in the sulfonyl benzene ring. Further, the conformations of the N-C bonds in the C-SO 2 -NH-C segment have gauche torsions with respect to the S═O bonds.
The molecule is bent at the S atom with C-SO 2 -NH-C torsion angle of -60.84 (18) 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 structure, the pairs of intermolecular N-H···O hydrogen bonds (Table 1) link the molecules into inversionrelated 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 3,4-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-(3,4-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 atom of the NH group was located in a difference map and later restrained to N-H = 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. The isotropic displacement parameters of the H atoms 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.