2,5-Dichloro-N-cyclohexylbenzenesulfonamide

The structure of the title sulfonamide, C12H15Cl2NO2S, features a distorted tetrahedral geometry for the S atom [maximum deviation: O—S—O = 120.23 (14)°]. One of the sulfonamide O atoms is coplanar with the benzene ring [C—C—S—O torsion angle = −174.5 (2)°], whereas the other lies well above the plane [C—C—S—O = 57.0 (3)°]. A chair conformation is found for the cyclohexyl ring. In the crystal, supramolecular chains aligned along the c axis are formed via N—H⋯O hydrogen bonds; these are consolidated in the three-dimensional packing by C—H⋯O contacts involving the second sulfonamide O atom.

The structure of the title sulfonamide, C 12 H 15 Cl 2 NO 2 S, features a distorted tetrahedral geometry for the S atom [maximum deviation: O-S-O = 120.23 (14) ]. One of the sulfonamide O atoms is coplanar with the benzene ring [C-C-S-O torsion angle = À174.5 (2) ], whereas the other lies well above the plane [C-C-S-O = 57.0 (3) ]. A chair conformation is found for the cyclohexyl ring. In the crystal, supramolecular chains aligned along the c axis are formed via N-HÁ Á ÁO hydrogen bonds; these are consolidated in the three-dimensional packing by C-HÁ Á ÁO contacts involving the second sulfonamide O atom.
The amide-H lies to the same side of the molecule as does the ortho-substituted Cl atom and approaches this atom at 2.85 (3) Å. The cyclohexyl ring adopts a chair conformation.
The presence of N1-H···O2 hydrogen bonding, Table 1, leads to the formation of supramolecular chains along the c axis, Fig. 2. Chains are consolidated in the 3-D packing by C4-H···O1 interactions, Fig. 3 and Table 1.

Experimental
To 2,5-dichlorobenzenesulfonyl chloride (491 mg, 2 mmol) in 10 ml distilled water, was added cyclohexylamine (229 µl, 2 mmol) with stirring at room temperature while maintaining the pH of reaction mixture at 8 by using 3% sodium carbonate solution. The progress of reaction was monitored by TLC. After consumption of reactants, the precipitates were filtered, dried and crystallized from methanol

Refinement
The C-bound H atoms were geometrically placed (C-H = 0.93-0.98 Å) and refined as riding with U iso (H) = 1.2U eq (C). The N-bound H atom was refined with the distance restraint N-H = 0.88±0.01 Å, and with U iso (H) = 1.2U eq (N). In the final refinement two low angle reflections evidently effected by the beam stop were omitted, i.e. (110) and (110). Fig. 1. The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level.