N-(2-Formylphenyl)-4-methyl-N-[(4-methylphenyl)sulfonyl]benzenesulfonamide

In the title compound, C21H19NO5S2, the dihedral angles between the formylphenyl ring and the two methylphenyl rings are 29.3 (3) and 28.9 (3)°, respectively; the dihedral angle between the methylphenyl rings is 48.4 (2)°. The C—N—S—C torsion angles are −74.1 (2) and −105.4 (2)°. In the crystal, molecules are linked by pairs of C—H⋯O hydrogen bonds, forming inversion dimers.

In the title compound, C 21 H 19 NO 5 S 2 , the dihedral angles between the formylphenyl ring and the two methylphenyl rings are 29.3 (3) and 28.9 (3) , respectively; the dihedral angle between the methylphenyl rings is 48.4 (2) . The C-N-S-C torsion angles are À74.1 (2) and À105.4 (2) . In the crystal, molecules are linked by pairs of C-HÁ Á ÁO hydrogen bonds, forming inversion dimers.

Structural commentary
Sulfonamides, which are already known as sulfa drugs, are an important class of compounds in the field of chemistry, biology 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 have been shown to inhibit on carbonic anhydrases (Suparan et al., 2000). Disulfonamides containing two sulfone groups connected to the nitrogen atom are used for their antitumor activity and carbonic anhydrases inhibitory properties (Boriack-Sjodin et al., 1998). In view of these potential applications and in continuation of our work, the structure of the title compound has been carried out and the results are presented here.

Synthesis and crystallization
A solution of 4 M Na 2 CO 3 in water (35 mL) was added to a solution of 2-aminobenzyl alcohol (5.0 mmol) and p-toluenesulfonyl chloride (12.0 mmol) in THF (10 mL). After stirring at room temperature for 24 h, the reaction mixture was poured into cold water and extracted with EtOAc. The resultant organic layer was washed with brine and dried over MgSO 4 . The resulting residue was purified by silica gel chromatography to afford 2-(ditoluensulfonylamino)benzyl alcohol. Next, to solution of 2-(ditoluensulfonylamino)benzyl alcohol in CH 2 Cl 2 (10 mL) was added excess MnO 2 (20 mmol). After stirring for at room temperature for 36 h, the reaction mixture was filtered under celite pad and purified by silica gel chromatography to afford the title compounds. Crystals suitable for X-ray analysis were obtained by recryatallization from an n-hexane/CH 2 Cl 2 solution.

Refinement
All H atoms were positioned geometrically, (C-H = 0.95-0.96 Å) and constrained to ride on their parent atoms, with U iso (H) = xUeq(C), where x = 1.2 for all other H atoms.

Figure 1
A view of the molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.42 e Å −3 Δρ min = −0.64 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 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.