(2S)-3-Carbamoyl-2-(4-methoxybenzenesulfonamido)propanoic acid

In the title compound, C11H14N2O6S, an amino acid-derived sulfonamide, the acetamido group and the carboxylic group are oriented at dihedral angles of 45.84 (5)° and 47.97 (5)° respectively, with respect to the aromatic ring. In the crystal, the molecules are connected by N—H⋯O and O—H⋯O hydrogen bonds and weak C—H⋯O interactions, forming a three-dimensional network.

In the title compound, C 11 H 14 N 2 O 6 S, an amino acid-derived sulfonamide, the acetamido group and the carboxylic group are oriented at dihedral angles of 45.84 (5) and 47.97 (5) respectively, with respect to the aromatic ring. In the crystal, the molecules are connected by N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds and weak C-HÁ Á ÁO interactions, forming a three-dimensional network.

Comment
Amino acid derived sulfonamide derivatives have been used as potent inhibitors of Procollagen C-Proteinase (Dankwardt et al., 2002). This structure is in countinuation to already reported crystal structures of sulfonamides derived from amino acids (Arshad et al., 2009a), (Arshad et al., 2009b) (Khan et al., 2009) by our group.
The dihedral angle between the acetamido group attached at the C7 and the carboxylic group C7/C8/O3/O4 is 38.64

Experimental
To the solution of L-asparagine (0.5 g, 3.78 mmol) in distilled water (10 ml), 4-methoxybenzenesulfonyl chloride(0.78 g, 3.78 mmol) was suspended. The reaction mixture was allowed to stirr at room temperature for 2 hrs. The pH of the solution was maintained at 8-9 by 1M sodium carbonate solution through out the reaction. After completion of the reaction which was observed by the consumption of suspended 4-methoxybenzenesulfonyl chloride, 1 N HCl solution was used to adjusted the pH about 2-3, which results in the formation of a white precipitate, which was filtered off, dried and recrystallized in methanol by slow evaporation to yield colorless needles of (I).

Refinement
The C-H H-atoms were positioned geometricaly with C-H = 0.95 Å, C-H = 0.99Å and C-H = 1.00 Å for aromatic, methylene and chiral carbon atoms respectively, and were refined using a riding model with U iso (H) = 1.2 U eq (C). Similarly the C-H H-atoms were positioned geometricaly with C-H = 0.98 Å for methyl group and were refined using a riding model with U iso (H) = 1.5 U eq (C). The N-H and O-H H atoms were located in difference map with N-H= 0.81 (2)-0.93 (2)Å and O-H= 0.81 (2) with U iso (H) = 1.2 for N atoms and U iso (H) = 1.5 for O atoms. The three reflections (001), (002) and (003) were omitted during the final refinement as these were obscured by the beam stop. Fig. 1. The molecular structure of (I) with displacement ellipsoids drawn at the 50% probability level.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.