4-Methyl-N-(4-methylphenylsulfonyl)-N-phenylbenzenesulfonamide

The whole molecule of the title compound, C20H19NO4S2, is generated by twofold rotational symmetry. The N atom is located on the twofold rotation axis and has a trigonal-planar geometry. It is bonded by two S atoms of two symmetry-related 4-methylphenylsulfonyl groups and by the C atom of the phenyl ring, which is bisected by the twofold rotation axis. The benzene and phenyl rings are oriented at a dihedral angle of 51.48 (5)° while the pendant benzene rings are inclined to one another by 87.76 (9)°. In the crystal, weak C—H⋯O hydrogen bonds link the molecules, forming a three-dimensional network.


Experimental
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009  Sulfonamides, which are known as sulfa drugs, are an important class of compounds in the field of chemistry and pharmacology. Several sulfonamide derivatives are used as chemotherapeutic agents for their antibacterial, antifungal, antitumor and hypoglycemic (Chohan et al., 2010;El-Sayed et al., 2011;Seri et al., 2000). In addition, some sulfonamide derivatives are reported to have carbonic anhydrases (CA) inhibition properties (Suparan et al., 2000). Disulfonamides are sulfonamide derivatives containing two sulfone groups connected to the nitrogen atom and they are used for their antitumor activity and CA inhibitory properties (Boriack-Sjodin et al., 1998). On the other hand, the complexes obtained from their chiral derivatives are used in asymmetric syntheses as catalysts (Guo et al., 1997). The title compound, belonging to the disulfonimide group, was synthesized and its crystal structure is reported herein.
The asymmetric unit of the title compound contains half a molecule; the whole molecule is generated by two-fold rotational symmetry. Atoms N1, C7 and C10 are located on the two-fold rotation axis (Fig. 1). The geometry around atoms S1 and N1 are distorted tetrahedral and planar trigonal, respectively. The average S-O bond length is 1.4213 (13) Å, while the S-N and S-C bond lengths are 1.6822 (9) and 1.7546 (17), respectively. These distances are close to standard values (Allen et al., 1987) and may be compared with the corresponding values in 5-amino-1-(4-methylphenylsulfonyl)-4-pyrazolin-3-one (Elgemeie et al., 2013). The benzene and phenyl rings are oriented at a dihedral angle of 51.48 (5)°. Atoms S1, C11 and N1 are displaced by -0.0757 (4), -0.0172 (26) and -0.0018 (1) Å from the adjacent ring planes.
In the crystal, Fig. 2, weak C-H···O hydrogen bonds (Table 1) link the molecules into a three-dimensional network.

Experimental
The title compound was prepared by a two step sulfonylation of aniline by 4-toluenesulfonyl chloride utilizing standard procedures with small modifications (DeChristopher et al., 1974). Aniline (40 mmol) and benzene (10 ml) were placed in a two-necked flask fitted with a dropping funnel and a reflux condenser. A solution of 4-toluenesulfonyl chloride (20 mmol) in benzene (50 ml) was placed in the dropping funnel and was added to the aniline solution in portions with stirring. The mixture was heated under reflux for 2 h. The obtained heterogeneous mixture was cooled and the solvent was evaporated under vacuum. The crude product was treated sequentially with deionized water (20 ml) and NaOH (20%) solution. The mixture was placed in a separation funnel and the water phase was separated and acidified gently with 4M HCl. The precipitate 4-toluene sulfonanilide was collected by filtration, and then dried (yield: 3.66 g, 74%; m.p. 372-373 K). In the second step 4-toluene sulfonanilide (10 mmol) was dissolved in benzene (30 ml) and the mixture stirred under reflux. A solution of 4-toluenesulfonyl chloride (10 mmol) in benzene (30 ml) was added drop wise into the stirring solution, and then potassium tert-butoxide (12 mmol), followed by catalytic amounts of 18-crown-6 were added in portions. After the reaction system was allowed to reflux for 3 h, then the mixture was cooled and the solvent evaporated under vacuum. The crude product was treated with NaOH (20%) solution in order to remove excess 4-toluene supplementary materials sup-2 Acta Cryst. (2014). E70, o238-o239 sulfonanilide. The insoluble solids were collected by filtration, washed with deionized water, and then dried (yield: 3.21 g, 78%; m.p. 454-456 K). The suitable colourless block-like crystals were obtained by recrystallization from acetone/water (7:3).

Refinement
The C-bound H-atoms were positioned geometrically with C-H = 0.93 and 0.96 Å for aromatic and methyl H-atoms, respectively, and constrained to ride on their parent atoms, with U iso (H) = k × U eq (C), where k = 1.5 for methyl H-atoms and = 1.2 for other H-atoms.

Figure 1
A view of the molecular structure of the title molecule, with atom-labelling. Displacement ellipsoids are drawn at the 50% probability level. The two-fold rotation axis bisects atoms N1, C7 and C10.  A partial view along the c axis of the crystal packing of the title compound. Hydrogen atoms have been omitted for clarity. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.24 e Å −3 Δρ min = −0.39 e Å −3 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. 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 > 2sigma(F 2 ) is used only for calculating R-factors(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.