N-{4-[(4-Methylphenyl)sulfamoyl]phenyl}acetamide

The title molecule, C15H16N2O3S, has a twisted U-shaped conformation. The twist occurs in the central C—S(=O)2N(H)—C unit with the C—S—N—C torsion angle being −58.38 (14)°. The benzene rings lie to the same side of the molecule and form a dihedral angle of 67.03 (10)°. The crystal packing features N—H⋯O hydrogen bonding, which leads to supramolecular chains with a tubular topology along the b axis. Intramolecular C—H⋯O interactions are also observed.

The title molecule, C 15 H 16 N 2 O 3 S, has a twisted U-shaped conformation. The twist occurs in the central C-S( O) 2 N(H)-C unit with the C-S-N-C torsion angle being À58.38 (14) . The benzene rings lie to the same side of the molecule and form a dihedral angle of 67.03 (10) . The crystal packing features N-HÁ Á ÁO hydrogen bonding, which leads to supramolecular chains with a tubular topology along the b axis. Intramolecular C-HÁ Á ÁO interactions are also observed.   Table 1 Hydrogen-bond geometry (Å , ).  (Kazmierski et al., 2004) and as anti-hypertensive drugs (Beate et al., 1998). In connection with on-going structural studies of sulfonamides (Khan et al., 2010;Sharif et al., 2010), the crystal and molecular structure of the title compound, (I), was investigated.

Related literature
To a first approximation, the molecule of (I), Fig. 1, has a twisted U-shaped conformation with the two benzene residues projecting to the same side of the molecule with reference to the central S(═O) 2 N moiety but, being splayed with respect to each other. The dihedral angle formed between the two benzene rings is 67.03 (10) ° and the C1-N1-S1-C8 torsion angle of -58.38 (14) ° indicates a twist in the molecule. Both S-bound O atoms lie to one side of the S-bound benzene ring [the O1-S1-C8-C9 torsion angle = 169.12 (13) ° and O2-S1-C8-C9 = 39.25 (15) °], and the N1 atom to the other [N1-S1-C8-C9 = -73.19 (15) °]. The amide group is co-planar with the benzene ring to which it is attached as seen in the C10-C11-N2-C14 torsion angle of 7.2 (3) °.
The formation of N-H···O hydrogen bonds dominate the crystal packing, Table 1. Thus, the sulfamoyl-N1-H hydrogen bonds to the amide-O, and the amide-N2-H hydrogen bonds to a sulfamoyl-O2 atom; the sulfamoyl-O1 atom forms intramolecular C-H···O interactions as does the amide-O3 atom, Table 1

Experimental
A mixture of 4-methylaniline (250 mg, 2.33 mmol) and 4-(acetylamino)benzenesulfonyl chloride (545 mg, 2.33 mmol) in distilled water (25 ml) was stirred, while maintaining pH of the reaction mixture at 8-10 by adding 3% sodium carbonate solution. The reaction was monitored by TLC. After completion of the reaction, precipitates were filtered, washed and dried.
The crude product obtained was crystallized by dissolving in methanol followed by slow evaporation of the solvent. M.
The N-bound H atoms were refined with the distance restraint N-H = 0.88±0.01 Å, and with U iso (H) = 1.2U eq (N). In the final refinement three low angle reflections evidently effected by the beam stop were omitted, i.e. 0 0 1, 0 1 0, and 0 1 1.  Fig. 1. The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 35% probability level.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The 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 > 2σ(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.