N-(2-Chlorophenyl)-2,4-dimethylbenzenesulfonamide

In the title compound, C14H14ClNO2S, the conformation of the N—C bond in the C—SO2—NH—C segment has gauche torsions with respect to the S=O bonds. The molecule is bent at the S atom with a C—SO2—NH—C torsion angle of −54.9 (2)°. The sulfonyl and aniline benzene rings are rotated relative to each other by 75.7 (1)°. An intramolecular N—H⋯Cl hydrogen bond is present. In the crystal, intermolecular N—H⋯O hydrogen-bonding interactions are observed and the molecules are packed into chains parallel to the b axis.


Comment
As part of a study of the substituent effects on the structures of N-(aryl)-arylsulfonamides (Gowda et al. , 2009a(Gowda et al. , ,b, 2010, in the present work the structure of 2,4-dimethyl-N-(2-chlorophenyl)benzenesulfonamide (I) has been determined (Fig. 1). The The structure shows simultaneous N-H···Cl intramolecular and N-H···O intermolecular H-bonding (Table 1). The crystal packing of molecules in (I) via N-H···O(S) hydrogen bonds is shown in Fig.2.

Experimental
A solution of 1,3-xylene (1,3-dimethylbenzene) (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-dimethylbenzenesulfonylchloride was treated with 2-chloroaniline 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 2,4-dimethyl-N-(2-chlorophenyl)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). The prism like colourless single crystals used in X-ray diffraction studies were grown by slow evaporation of an ethanol solution 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 (1) %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).  Fig. 1. Molecular structure of (I), showing the atom labelling scheme and displacement ellipsoids drawn at the 50% probability level.
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.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.