N-(2-Bromophenyl)-4-methyl-N-(4-methylphenylsulfonyl)benzenesulfonamide

In the title compound, C20H18BrNO4S2, the mean planes formed by the toluene substituents are inclined at a dihedral angle of 45.34 (8)°. The bromobenzene group is disordered over two positions with an occupancy ratio of 0.74:0.26, resulting in two conformations of the ring; the two rings are oriented at a dihedral angle of 6.6 (6)° with each other. In the crystal structure, weak C—H⋯O interactions connect the molecules in a zigzag manner along the a axis.

In the title compound, C 20 H 18 BrNO 4 S 2 , the mean planes formed by the toluene substituents are inclined at a dihedral angle of 45.34 (8) . The bromobenzene group is disordered over two positions with an occupancy ratio of 0.74:0.26, resulting in two conformations of the ring; the two rings are oriented at a dihedral angle of 6.6 (6) with each other. In the crystal structure, weak C-HÁ Á ÁO interactions connect the molecules in a zigzag manner along the a axis.   Table 1 Hydrogen-bond geometry (Å , ).  Herein, we report the crystal structure of the title compound which was synthesised as a precursor of cyclic sultams (Arshad et al., 2011).

Related literature
The N-atom of O-bromoaniline is directly attached to two p-toluene sulfonyl moieties. The interesting feature in the crystal structure is that bromobenzene group is disordered over two positions (C15-C20/Br1) and (C21-C26/Br2) with the occupancy of 0.74 and 0.26, respectively. The dihedral angle between the two disordered parts of the ring is 6.6 (6)°.

Experimental
A mixture of 2-bromoaniline (300 mg, 1.7 mmol) and triethylamine (529 mg, 5.2 mmol) was prepared in dichloromethane (20ml). Toluene sulfonylchloride (650 mg, 3.4 mmol) was added to the mixture and stirred for about two hours. The mixture was poured on ice and pH was adjusted about 2-3. The precipitate obtained was filtered, washed and dried. Suitable crystals were produced in methanol by slow evaporation.

Refinement
The H-atoms were positioned at idealized geometry with C-H = 0.95 and 0.98 Å for aryl and methyl groups, respectively, and were refined using a riding model with U iso (H) = 1.2 U eq (C) for aromatic & U iso (H) = 1.5 U eq (C) for methyl groups.
The bromobenzene ring was disordered over two positions with occupancy ratio 0.74: 0.26. The occupancy factors were established in earlier stages of refinement and were fixed in the final refinement cycles. The benzene ring of the smaller fraction of the bromobenzene fragment was constrained as a regular hexagon  Fig. 1. An ORTEP diagram of the title compound with thermal ellipsoids drawn at the 50% probability level; smaller fraction of the disordered bromobenzene ring has been plotted with dashed lines.

Special details
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.