2,2-Dimethyl-N-(2-methylphenylsulfonyl)acetamide

The asymmetric unit of the title compound, C11H15NO3S, contains two independent molecules in which the amide bonds show a trans conformation. The C—S—N—C torsion angles are −67.4 (2) and 63.8 (2)° in the two independent molecules. In one of the molecules, a methyl group is disordered over two sets of sites with a site-occupation factor of 0.661 (16) for the major occupany component. In the crystal, molecules are packed into chains running along [101] through N—H⋯O(S) hydrogen bonds.

The asymmetric unit of the title compound, C 11 H 15 NO 3 S, contains two independent molecules in which the amide bonds show a trans conformation. The C-S-N-C torsion angles are À67.4 (2) and 63.8 (2) in the two independent molecules. In one of the molecules, a methyl group is disordered over two sets of sites with a site-occupation factor of 0.661 (16) for the major occupany component. In the crystal, molecules are packed into chains running along [101] through N-HÁ Á ÁO(S) hydrogen bonds.
KS thanks the University Grants Commission, Government of India, New Delhi, for the award of a research fellowship under its faculty improvement program.
Further, in both the independent molecules, the conformation of the amide H atoms are syn to the ortho-methyl groups in the benzene rings, similar to that observed between the amide H atom and the ortho-methyl group in (II), but contrary to the anti conformation observed between the amide H atom and the ortho-chloro group in (III).
In the crystal structure, the intermolecular N-H···O hydrogen bonds (Table 1) link the molecules into chains. 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 2,2-dimethylacetyl 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 reprecipitated by acidifying the filtered solution with glacial acetic acid. It was filtered, dried and recrystallized from ethanol. The purity of the compound was checked by determining its melting point.
It was further characterized by recording its infrared spectra.
Prism like colorless single crystals of the title compound used in X-ray diffraction studies were obtained from a slow evaporation of an ethanolic solution of the compound.

Refinement
The H atoms of the NH groups were located in a difference map and later restrained to the distance N-H = 0.86 (2) Å.
The other H atoms were positioned with idealized geometry using a riding model the with aromatic C-H distance = 0.93 supplementary materials sup-2 Å, methyl C-H = 0.96 Å, methyne C-H = 0.98 Å. All H atoms were refined with isotropic displacement parameters (set to 1.2 times of the U eq of the parent atom).
The atom C10 is disordered and was refined using a split model. The corresponding site-occupation factors were refined so that their sum was unity [0.66 (2) and 0.34 (2)]. The distance C8-C10 was restrained to 1.55 (1) Å and the corresponding bond distances in the disordered group were restrained to be equal.