N-(4-Methylphenylsulfonyl)succinamic acid

In the crystal structure of the title compound, C11H13NO5S, the amide C=O and the carboxyl C=O groups of the acid segment orient themselves away from each other. The dihedral angle between the benzene ring and the amide group is 69.0 (2)°. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds link the molecules into layers parallel to the bc plane.

In the crystal structure of the title compound, C 11 H 13 NO 5 S, the amide C O and the carboxyl C O groups of the acid segment orient themselves away from each other. The dihedral angle between the benzene ring and the amide group is 69.0 (2) . In the crystal, N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds link the molecules into layers parallel to the bc plane.

D-HÁ
Data collection: CrysAlis CCD (Oxford Diffraction, 2009); cell refinement: CrysAlis RED (Oxford Diffraction, 2009); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97. As part of our studies on the substituent effects on the structures and other aspects of N-(aryl)-amides (Gowda et al., 2000;Saraswathi et al., 2011); N-chloroarylsulfonamides (Gowda & Rao, 1989;Jyothi & Gowda, 2004) and N-bromoaryl-sulfonamides (Gowda & Mahadevappa, 1983;Usha & Gowda, 2006), in the present work, the crystal structure of N-(4-methylphenylsulfonyl)succinamic acid has been determined ( Fig. 1). The conformations of the N-H and C=O bonds in the amide segment are anti to each other. Further, the amide C═O and the carboxyl C═O of the acid segment orient themselves away from each other, in contrast to the anti conformation observed between the the amide oxygen and the carboxyl oxygen in N-(4-methylphenyl)-succinamic acid (I) (Saraswathi et al., 2011). But both the amide oxygen and the carboxyl oxygen are anti to the H atoms on the adjacent -CH 2 groups, in both the compounds.
In the title compound, the C═O and O-H bonds of the acid group are in syn position to each other, similar to that observed in (I). The molecule is bent at the S-atom with the C1-S1-N1-C7 torsion angle of 79.2 (1)°. Further, the dihedral angle between the phenyl ring and the amide group is 69.0 (2)°. In the crystal, the pairs of O-H···O and N-H···O intermolecular hydrogen bonds link the molecules into layers parallel to the bc plane (Table 1, Fig. 2).

Experimental
Succinic anhydride (0.015 mole) and 4-dimethylaminopyridine (0.01 mole) were added to a solution of p-toluenesulfonamide (0.01 mole) in dichloromethane. The reaction mixture was strirred for 18 h at room temperature and set aside for completion of the reaction. The reaction mixture was concentrated to dryness. The resultant title compound was washed with dilute HCl and then with water thoroughly, to remove the unreacted base and the succinic anhydride. It was recrystallized to constant melting point from ethyl acetate (173-175 °C). The purity of the compound was checked and characterized by its infrared spectrum. Prism-like colourless single crystals used in X-ray diffraction studies were grown by slow evaporation of an ethyl acetate solution at room temperature.

Refinement
The H atoms of the NH group and the OH group were located in a difference Fourier map and later restrained to the distances of N-H = 0.86 (2) Å and O-H = 0.82 (2) Å, respectively. The other H atoms were positioned with idealized geometry using a riding model with the aromatic C-H = 0.93 Å, methyl C-H = 0.96 Å and methylene C-H = 0.97 Å.
All H atoms were refined with isotropic displacement parameters set at 1.2 U eq (C-aromatic, N) and 1.5 U eq (C-methyl).

Figure 2
The molecular packing of the title compound with hydrogen bonding shown as dashed lines. 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.