N-(2-Chlorophenylsulfonyl)-2-methylpropanamide

In the title compound, C10H12ClNO3S, the amide H atom is syn with respect to the ortho-chloro group in the benzene ring and the C—S—N—C torsion angle is 64.35 (16)°. The benzene ring and the SO2—NH—CO—C segment form a dihedral angle of 87.4 (1)°. The crystal structure features inversion-related dimers linked by pairs of N—H⋯O hydrogen bonds.

In the title compound, C 10 H 12 ClNO 3 S, the amide H atom is syn with respect to the ortho-chloro group in the benzene ring and the C-S-N-C torsion angle is 64.35 (16) . The benzene ring and the SO 2 -NH-CO-C segment form a dihedral angle of 87.4 (1) . The crystal structure features inversionrelated dimers linked by pairs of N-HÁ Á ÁO 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.

Comment
The molecular structures of sulfonamide drugs contain the sulfanilamide moiety (Maren, 1976). The affinity for hydrogen bonding in the solid state due to the presence of various hydrogen bond donors and acceptors can give rise to polymorphism (Yang & Guillory, 1972). The hydrogen bonding preferences of sulfonamides has also been investigated (Adsmond & Grant, 2001). The nature and position of substituents play a significant role on the crystal structures of N-(aryl)sulfonoamides (Gowda et al., 2008(Gowda et al., , 2009(Gowda et al., , 2010. As a part of studying the substituent effects on the structures of this class of compounds, the In the crystal structure, the intermolecular N-H···O hydrogen bonds (Table 1) link the molecules through inversion-related dimers into zigzag chains in the bc-plane. Part of the crystal structure is shown in Fig. 2.

Experimental
The title compound was prepared by refluxing 2-chlorobenzenesulfonamide (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 atom of the NH group was 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 with C-H = 0.93-0.98 Å. All H atoms were refined with isotropic displacement parameters (set to 1.2 times of the U eq of the parent atom).   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.