N-(2,4-Dichlorophenyl)-4-methylbenzenesulfonamide

The molecule of the title compound, C13H11Cl2NO2S, is bent at the S atom with a C—SO2—NH—C torsion angle of −69.07 (16)°. The sulfonyl and aniline rings are rotated relative to each other by 53.0 (1)°. In the crystal, pairs of N—H⋯O(S) hydrogen bonds link the molecules into centrosymmetric dimers.

In the crystal, the N-H···O hydrogen bonds (Table 1) pack the molecules into zigzag chains in the direction parallel to b-axis (Fig. 2).

Experimental
The solution of toluene (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 4-methylbenzenesulfonylchloride was treated with 2,4-dichloroaniline 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 N-(2,4-dichlorophenyl)-4-methylbenzenesulfonamide 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 (Shetty & Gowda, 2005).
The prism like colourless single crystals used in X-ray diffraction studies were grown in ethanolic solution by a 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 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.

Special details
Geometry. All e.s. 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.