4-[5-(4-Chlorophenyl)-3-methyl-1H-pyrazol-1-yl]benzenesulfonamide

In the title compound, C16H14ClN3O2S, the dihedral angle between the benzene and pyrazole rings is 52.75 (2)°, while that between the pyrazole and 4-chlorophenyl rings is 54.0 (3)°. The terminal sulfonamide group adopts an approximately tetrahedral geometry about the S atom with a C—S—N angle of 108.33 (10)°. In the crystal, pairs of N—H⋯N hydrogen bonds lead to the formation of inversion dimers. These dimers are linked via a second pair of N—H⋯N hydrogen bonds and C—H⋯O interactions, forming a two-dimensional network lying parallel to the bc plane. The two-dimensional networks are linked via C—H⋯Cl interactions, forming a three-dimensional structure.

In the title compound, C 16 H 14 ClN 3 O 2 S, the dihedral angle between the benzene and pyrazole rings is 52.75 (2) , while that between the pyrazole and 4-chlorophenyl rings is 54.0 (3) . The terminal sulfonamide group adopts an approximately tetrahedral geometry about the S atom with a C-S-N angle of 108.33 (10) . In the crystal, pairs of N-HÁ Á ÁN hydrogen bonds lead to the formation of inversion dimers. These dimers are linked via a second pair of N-HÁ Á ÁN hydrogen bonds and C-HÁ Á ÁO interactions, forming a twodimensional network lying parallel to the bc plane. The twodimensional networks are linked via C-HÁ Á ÁCl interactions, forming a three-dimensional structure.
The molecular assembly is built on the basis of intermolecular N-H···N type hydrogen bonds. The N3 atom on one side accepts a H1N1 atom from a neighbouring atom at a distance of 2.33 (3) Å and also accepts a H2N1 atom from a molecule on the opposite side at a distance of 2.20 (2) Å. There is a weak C-H···O type intermolecular hydrogen bond where the C5 atom donates its H atom to the O2 of the sulfonamide group at a distance of 2.48 Å and C-H-O angle of 130.8°. The molecule is also involved in the formation of a pair of weak intermolecular inversion related C3-H3···Cl1 hydrogen bonds where in one case the Cl1 atom accepts a H atom from a neighbouring molecule while in return, the C3 atom donates its H3 atom to the same molecule. The C-H···Cl distance in both cases is 2.93 Å and C-H-Cl angle is 130.0°.

Experimental
A mixture of 1 mmol (197 mg) 1-(4-chlorophenyl)butane-1,3-dione, 1 mmol (224 mg) 4-hydrazinylbenzenesulfonamide hydrochloride, 82 mg sodium acetate and 60 mg glacial acetic acid in 50 ml e thanol was stirred at room temperature for 24 h. The mixture was filtered off and the filtrate was concentrated under vacuum to deposit the solid product which was collected, dried and recrystallized from ethanol to afford a very good yield (80%) of high quality crystals suitable for Xray diffraction (498 -499 K).

Refinement
The H atoms attached to N1 were located in a difference map and were refined freely. All the H atoms attached to aromatic carbon atoms were initially located in the difference map but subsequently refined with a distance restraint of 0.93 Å and Uiso(H) = 1.2Ueq(C). The H atoms attached to C10 atom were positioned geometrically at idealized positions for methyl and were refined with C-H distance of 0.96 Å and Uiso(H) = 1.5Ueq(C).

Figure 1
An ORTEPIII diagram of the molecule showing the atom numbering scheme and thermal ellipsoids drawn at the 50% probability level.    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 R-factors(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.