2-{4-[Acetyl(ethyl)amino]benzenesulfonamido}benzoic acid

In the title compound, C17H18N2O5S, the dihedral angle between the aromatic rings is 68.59 (10)° and the C—S—N—C torsion angle is −81.84 (18)°. The molecular conformation is stabilized by an intramolecular N—H⋯O hydrogen bond, generating an S(6) ring. In the crystal, molecules are linked by C—H⋯O and O—H⋯O hydrogen bonds into a three-dimensional network.

In the title compound, C 17 H 18 N 2 O 5 S, the dihedral angle between the aromatic rings is 68.59 (10) and the C-S-N-C torsion angle is À81.84 (18) . The molecular conformation is stabilized by an intramolecular N-HÁ Á ÁO hydrogen bond, generating an S(6) ring. In the crystal, molecules are linked by C-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds into a threedimensional network.  As part of our ongoing studies of sulfonamides with potential biological properties (Mustafa et al., 2010(Mustafa et al., , 2011Khan et al., 2011), we now describe the title compound, (I).
The molecular conformation of (I) is stabilized by intramolecular N-H···O hydrogen-bond interaction (Table 1), which generate one S(6) ring. In the crystal, molecules are linked by C-H···O and O-H···O hydrogen bonds to form a threedimensional network structure (Table 1, Fig. 2).

Experimental
To an aquious solution of p-amino benzoic acid (1.0 g, 7.3 mmol), sodium carbonate (1 N) was added to adjust the pH 8.
Then added 4-(acetylamino) benzenesulfonyl chloride (2.21 g, 9.48 mmol) and the mixture was stirred at room temperature keeping the pH of the mixture up to 8.0 with occasional addition of sodium carbonate solution. Progress and completion of the reaction was confirmed by TLC and conversion of suspension into clear solution. After 2 h, whole mixture was poured into a beaker and the pH was adjusted to 2.0 by 1 N HCl. Pprecipitates were produced which were filtered and washed with distilled water. The prepared sulfonamide (2-({[4-(acetylamino)phenyl]sulfonyl}amino) benzoic acid) (1.0 g, 3 mmol), DMF (10 ml) and n-hexane washed sodium hydride (0.22 g, 9.0 mmol) were stirred at room temperature for 40 min followed by the addition of ethyl iodide (0.61 g, 3.9 mmol). The whole reaction mixture was stirred till the completion of the reaction and poured into crushed ice in a beaker. The pH of the mixture was adjusted to 4.0 with 1 N HCl. Precipitates were produced, filtered and washed twice with distilled water and crystallized from chloroform solution as brown blocks.

Refinement
The NH H atom was located in a difference map and refined with the distance restraint N-H = 0.86 (2)  to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figure 1
The molecular structure of the title compound, showing displacement ellipsoids drawn at the 30% probability level.

Figure 2
View of the packing diagram and the hydrogen bonding of (I) along the c axis. Hydrogen atoms that not involved in the hydrogen-bonding (dashed lines) have been omitted for clarity.  (6) Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.