(E)-N′-(5-Chloro-2-hydroxybenzylidene)-p-toluenesulfonohydrazide

The title compound, C14H13ClN2O3S, features an intramolecular O—H⋯N hydrogen bond which generates an S(6) ring motif. Intermolecular N—H⋯O hydrogen bonds and C—H⋯O close contacts link neighbouring molecules forming R 2 2(13) ring motifs. In the crystal structure, molecules are further linked by C—H⋯Cl interactions, forming one-dimensional extended chains along the c axis. The dihedral angle between the two benzene rings is 86.06 (3)°. The crystal structure is further stabilized by weak intermolecular π–π interactions [interplanar stacking distance = 3.357 (7) Å].

The title compound, C 14 H 13 ClN 2 O 3 S, features an intramolecular O-HÁ Á ÁN hydrogen bond which generates an S(6) ring motif. Intermolecular N-HÁ Á ÁO hydrogen bonds and C-HÁ Á ÁO close contacts link neighbouring molecules forming R 2 2 (13) ring motifs. In the crystal structure, molecules are further linked by C-HÁ Á ÁCl interactions, forming onedimensional extended chains along the c axis. The dihedral angle between the two benzene rings is 86.06 (3) . The crystal structure is further stabilized by weak intermolecularinteractions [interplanar stacking distance = 3.357 (7) Å ].

Comment
Sulfonamides were the first class of antimicrobial agents to be discovered. Sulfonamides (sulfanilamide, sulfamethoxazole, sulfafurazole) are structural analogues of p-aminobenzoic acid (PABA) and compete with PABA to block its conversion to dihydrofolic acid (Kayser et al., 2004). These agents are generally used in combination with other drugs (usually sulfonamides) to prevent or treat a number of bacterial and parasitic infections (Tierney et al., 2006). With regard to all of the above important features, we report the crystal structure of the title compound.
The title compund (Fig. I), is a novel sulfonamide derivative. Bond lengths (Allen et al., 1987) and angles are within the normal ranges and are comparable with those in related structures (Kia et al., 2008;Mehrabi et al., 2008;Ali et al. 2007). An intramolecular O-H···N hydrogen bond generates S(6) ring motif, and the molecule adopts a 'vault' shape.
Intermolecular N-H···O and C-H···O interactions link neighbouring molecules by R 2 2 (13) ring motifs. The two benzene rings make a dihedral angle of 86.06 (3)°. In the crystal structure, molecules are linked together by intermolecular C-H···Cl, N-H···O and C-H···O interactions, forming one-dimensional extended chains along the c axis. The crystal structure is further stabilized by weak intermolecular π-π interactions [interplanar distance = 3.357 (7) Å].

Experimental
The synthetic method has been described earlier (Kia et al., 2008). Single crystals suitable for X-ray diffraction were obtained by evaporation of an ethanol solution at room temperature.

Refinement
The H atoms bound to O1 and N2 were found in a difference Fourier map and refined freely. The rest of the hydrogen atoms were positioned geometrically and refined using a riding model. A rotating group model was used for the methyl hydrogens.
The highest residual peak (0.44 e.Å -3 ) is located 0.66 Å from O2 and the deepest hole (-0.38 e.Å -3 ) is located 0.57 Å from S1. Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering scheme. The intramolecular hydrogen bond is shown as a dashed line.