N-{[4-(4-Methoxybenzenesulfonamido)phenyl]sulfonyl}acetamide

In the title compound, C15H16N2O6S2, the dihedral angle between the benzene rings is 83.2 (3)°. The molecular conformation is stabilized by an intramolecular C—H⋯O interaction. In the crystal structure, molecules are linked by N—H⋯O and C—H⋯O hydrogen bonds and additional stabilization is provided by weak C—H⋯π interactions.

In the title compound, C 15 H 16 N 2 O 6 S 2 , the dihedral angle between the benzene rings is 83.2 (3) . The molecular conformation is stabilized by an intramolecular C-HÁ Á ÁO interaction. In the crystal structure, molecules are linked by N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds and additional stabilization is provided by weak C-HÁ Á Á interactions.

Related literature
For previous studies on the synthesis of sulfonamide derivatives with phenyl glycine, see: Ashfaq et al. (2009Ashfaq et al. ( , 2010 Table 1 Hydrogen-bond geometry (Å , ).

Comment
Sulphacetamide sodium is an antibiotic which is being used for eye infections. Because the antiobiotics lose their efficacy after long term used, so there is a need to derivatize them to get better therapeutic result. In this paper, a new derivative of it is being reported. Previously this drug has also been derivatized by other researchers (Ashfaq et al., 2009(Ashfaq et al., , 2010. Here we present the crystal structure of the title compound (I), (Fig. 1).

Experimental
Sodium sulphacetamide (0.5 g, 2.32 mmol) was taken in 50 ml round bottom flask and dissolved in 20 ml of distilled water.
Then, methoxy benzene sulfonyl chloride (0.46 g, 2.32 mmol) was added with continuous stirring at ambient temperature.
The pH of this solution was strictly maintained between 8 and 9 by using NaHCO 3 (3 M). The consumption of suspended methoxy benzene sulfonyl chloride was an indication of reaction completion. Then pH was adjusted to 2-3 using HCl (3 N). The precipitates formed were filtered, washed three to four times with distilled water and recrystallised using methanol to yield colourless rods of (I).

Refinement
All H-atoms were positioned geometrically and refined using a riding model with d(N-H) = 0.86 Å, U iso = 1.2U eq (N) for NH, 0.93 Å, U iso = 1.2U eq (C) for aromatic and 0.96 Å, U iso = 1.5U eq (C) for CH 3 hydrogen atoms. Fig. 1 Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted Rfactors 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.