(E)-N′-(4-Chlorobenzylidene)-p-toluenesulfonohydrazide 0.15-hydrate

The asymmetric unit of the title compound, C14H13ClN2O2S·0.15H2O, a novel sulfonamide derivative, comprises two crystallographically independent molecules (A and B) and a water molecule of crystallization, which is partially occupied. One of the molecules (B) is disordered over two positions (B and C) with refined site occupancies of 0.605 (10) and 0.395 (10). The dihedral angles between the two benzene rings in molecules A, B and C are 67.8 (3), 74.6 (5) and 84.96 (11)°, respectively. In the crystal structure, intermolecular N—H⋯O and C—H⋯O hydrogen bonds link the components of the asymmetric unit. The crystal structure is further stabilized by intermolecular π–π interactions [centroid–centroid distances = 3.4518 (10)–3.5859 (10) Å].

The asymmetric unit of the title compound, C 14 H 13 ClN 2 O 2 SÁ-0.15H 2 O, a novel sulfonamide derivative, comprises two crystallographically independent molecules (A and B) and a water molecule of crystallization, which is partially occupied. One of the molecules (B) is disordered over two positions (B and C) with refined site occupancies of 0.605 (10) and 0.395 (10). The dihedral angles between the two benzene rings in molecules A, B and C are 67.8 (3), 74.6 (5) and 84.96 (11) , respectively. In the crystal structure, intermolecular N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds link the components of the asymmetric unit. The crystal structure is further stabilized by intermolecularinteractions [centroid-centroid distances = 3.4518 (10)-3.5859 (10) Å ].

Related literature
For bond-length data, see: Allen et al. (1987). For hydrogenbond motifs, see: Bernstein et al. (1995). For related structures and applications, see, for example: Kia et al.  Krygowski et al. (1998). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 Table 1 Hydrogen-bond geometry (Å , ).

Comment
Sulfonamides were the first class of antimicrobial agents to be discovered. They inhibit dihydropteroate synthetase in the bacterial folic acid pathway. Although their clinical role has diminished, they are still useful in certain situations because of its efficacy and low cost (Krygowski et al., 1998). Sulfonamides (sulfanilamide, sulfamethoxazole, sulfafurazole) are structural analogues of p-aminobenzoic acid (PABA) and compete with PABA to block its conversion to dihydrofolic acid.
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). Because of the above impotrtant features, we report the crystal structure of the title compound (I).
Experimental p-Tosylhydrazine (2 mmol) was added to a 50 ml refluxing ethanolic solution of 4-chlorobenzaldehyde (2 mmol). The mixture was stirred for 2 h. After cooling, the colorless crystalline solid was isolated by filtration, washed with cold ethanol, and re-crystallized from ethanol.

Refinement
The N-bound H atoms were located from the difference Fourier map and constrained to refine with the carrier atom with U iso (H) = 1.2 U eq (N). The rest of the hydrogen atoms were positioned geometrically and refined as riding model with U iso (H) = 1.2 or 1.5 U eq (C). A rotating group model was used for the methyl groups. For the disordered molecule, only the S and Cl atoms were refined anisotropically. Initially rigid, similarity and simulation restraints were applied. After steady state has been reached, these restraints were removed for the final refinement. There is no restraints used in the final refinement. Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering. Open bonds indicate the minor component.