N-(1-Allyl-3-chloro-4-ethoxy-1H-indazol-5-yl)-4-methylbenzenesulfonamide

In the title compound, C19H20ClN3O3S, the benzene ring is inclined to the indazole ring system by 51.23 (8)°. In the crystal, molecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers which stack in columns parallel to [011]. The atoms in the allyl group are disordered over two sets of sites with an occupancy ratio of 0.624 (8):0.376 (8).

In the title compound, C 19 H 20 ClN 3 O 3 S, the benzene ring is inclined to the indazole ring system by 51.23 (8) . In the crystal, molecules are linked by pairs of N-HÁ Á ÁO hydrogen bonds, forming inversion dimers which stack in columns parallel to [011]. The atoms in the allyl group are disordered over two sets of sites with an occupancy ratio of 0.624 (8):0.376 (8).   Table 1 Hydrogen-bond geometry (Å , ).
The molecule of the title compound is built up from two fused five-and six-membered rings (N1 N2 C1 to C7) almost coplanar, with a maximum deviation of -0.036 (2) Å for C5 atom (Fig.1). The indazol system forms a dihedral angle of 51.23 (8)° with the plane through the benzene ring and it is nearly perpendicular to the allyl group as indicated by the torsion angle C18B-C17-N2-N1 of 95.4 (5)°.
The cohesion of the crystal structure is ensured by N3-H3N···O3 hydrogen bonds between molecules forming a dimers, arranged in columns parallel to the [0 1 1] direction as shown in Fig.2 and Table 1.

Experimental
A mixture of 1-allyl-3-chloro-5-nitroindazole (1.22 mmol) and anhydrous SnCl 2 (1.1 g, 6.1 mmol) in 25 ml of absolute ethanol was heated at 333 K for 6 h. After reduction, the starting material disappeared, and the solution was allowed to cool down. The pH was made slightly basic (pH 7-8) by addition of 5% aqueous potassium bicarbonate before extraction with ethyl acetate. The organic phase was washed with brine and dried over magnesium sulfate. The solvent was removed to afford the amine, which was immediately dissolved in pyridine (5 ml) and then reacted with 4-methylbenzenesulfonyl chloride (1.25 mmol) at room temperature for 24 h. After the reaction mixture was concentrated in vacuo, the resulting residue was purified by flash chromatography (eluted with Ethyl acetate: Hexane 2:8). The title compound was recrystallized from ethanol (yield = 40%, m.p. = 373 K).

Refinement
The reflections (100), (010), (001) and (011) are removed from the refinement because they are affected by the beam stop. The structure is solved by direct method technique and refined by full-matrix least-squares using SHELXS97 and SHELXL97 program packages. H atoms were located in a difference map and treated as riding with C-H = 0.96 Å, C-H = 0.97 Å, C-H = 0.93 Å, and N-H = 0.89 Å for methyl, methylene, aromatic CH, and NH, respectively. All hydrogen with U iso (H) = 1.2 U eq (aromatic, methylene, NH)and U iso (H) = 1.5 U eq for methyl.     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.