N-(2-Methylphenylsulfonyl)acetamide

In the molecular structure of the title compound, C9H11NO3S, the N—H and C=O bonds are anti to each other, while the amide H atom is syn with respect to the ortho-methyl group in the benzene ring. The C—S—N—C torsion angle is −58.2 (2)°, indicating a twist in the molecule. In the crystal, N—H⋯O hydrogen bonds link the molecules into chains along the c axis.

In the molecular structure of the title compound, C 9 H 11 NO 3 S, the N-H and C O bonds are anti to each other, while the amide H atom is syn with respect to the ortho-methyl group in the benzene ring. The C-S-N-C torsion angle is À58.2 (2) , indicating a twist in the molecule. In the crystal, N-HÁ Á ÁO hydrogen bonds link the molecules into chains along the c axis.
KS thanks the University Grants Commission, Government of India, New Delhi, for the award of a research fellowship under its faculty improvement program.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: TK2737).

Comment
The structures of sulfonamide drugs contain the sulfanilamide moiety (Maren, 1976). The hydrogen bonding preferences of sulfonamides has been investigated (Adsmond & Grant, 2001). The nature and position of the substituents play a significant role on their crystal structures and other aspects of N-(aryl)-amides and N-(aryl)-sulfonamides (Gowda et al., 2003(Gowda et al., , 2004Shakuntala et al., 2011). As a part of a study of the effects of substituents on the structures of this class of compounds, the structure of N-(2-methylphenylsulfonyl)-acetamide (I) has been determined ( Fig. 1). The conformation of the N-C bond in the C-SO 2 -NH-C(O) segment has gauche torsions with respect to the S═O bonds, the torsion angles being C7-N1-S1-O2 = 57.5 (3) ° and C7-N1-S1-O1 = -174.5 (2) °.
The N-H and C═O bonds are anti to each other, similar to that observed in N-(phenylsulfonyl)-acetamide (II) (Gowda et al., 2010) and N-(2-chlorophenylsulfonyl)-acetamide (III) (Shakuntala et al., 2011). Further, the conformation of the amide-H atom is syn to the ortho-methyl group in the benzene ring, similar to that observed between the amide-H atom and the ortho-chloro group in (III). The molecule of (I) is bent at the S-atom with a C-S-N-C torsion angle of -58.2 (2) °, compared to the values of -58.8 (4) ° in (II), and -71.7 (3) and 61.2 (3) ° in the two independent molecules of (III).
In the crystal structure, intermolecular N-H···O hydrogen bonds (Table 1) link the molecules into chains along the c axis; part of the crystal structure is shown in Fig. 2.

Experimental
The title compound was prepared by refluxing 2-methylbenzenesulfonamide (0.10 mole) with an excess of acetyl chloride (0.20 mole) for one hour on a water bath. The reaction mixture was cooled and poured into ice cold water. The resulting solid was separated, washed thoroughly with water and dissolved in warm dilute sodium hydrogen carbonate solution. The title compound was re-precipitated by acidifying the filtered solution with glacial acetic acid. It was filtered, dried and recrystallized from ethanol. Colourless rods of the title compound were obtained from a slow evaporation of its ethanol solution.

Refinement
The H atom of the NH group was located in a difference map and later restrained to the distance N-H = 0.86±0.02 Å. The other H atoms were positioned with idealized geometry using a riding model with the aromatic C-H distance = 0.93 Å and methyl C-H = 0.96 Å. All H atoms were refined with isotropic displacement parameters set to 1.2 times of the U eq of the parent atom.
supplementary materials sup-2 Figures   Fig. 1. Molecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.  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 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1 0.0401 (