A simple and efficient process is developed for the synthesis of new N‐(1‐alkyl‐3‐chloro‐4‐ethoxy‐1H‐indazol‐5‐yl)‐arylsulfonamides 4a–d and N‐(1‐alkyl‐3‐chloro‐1H‐indazol‐5‐yl)‐arylsulfonamides 5a–d through the reduction of 1‐alkyl‐3‐chloro‐5‐nitroindazoles 2a,b with SnCl2 in ethanol followed by coupling the corresponding amine with arylsulfonyl chlorides in pyridine. All the newly synthesized compounds have been characterized by elemental analysis and spectroscopic data. Some compounds were tested for their in vitro antiproliferative activities against two selected human cancer cell lines A2780 and A549. Among all of these derivatives, compound 5d showed the most potent antiproliferative activity against A2780 (IC50 = 5.47 ± 1.45 μM) and A549 (IC50 = 7.73 ± 1.66 μM) cell lines.

A new series of 1-and 6-Substituted 1H-indazoles 2-6 were synthesized in moderate yield, through a simple synthetic strategy using 6-nitroindazole as key intermediate. The cytotoxicity of synthetic compounds was evaluated against kidney carcinoma cell line (BSR) and the human larynx carcinoma (Hep). Some of the newly prepared compounds indicated significant inhibitory activity against these cells in vitro.

In the title compound, C21H25N3O6S, the dihedral angle between the meth­oxy­benzene and indazole rings is 74.96 (5)°. The crystal packing is stabilized by an N—H⋯O hydrogen bond into a two-dimensional network. In addition, C—H⋯π inter­actions and a π–π contact, with a centroid–centroid distance of 3.5333 (6) Å, are observed. The crystal packing is stabilized by N—H⋯O and C—H⋯O hydrogen bonds.

In the title compound, C14H10N4O6S, the indazole ring system is almost perpendicular to the tosyl ring, as indicated by the dihedral angle of 89.40 (9)° between their planes. The dihedral angles between the indazole system and the nitro groups are 57.0 (3) and 31.9 (3)°. In the crystal, mol­ecules are linked by C—H⋯O inter­actions, forming chains running along [100].

Key indicators: single-crystal X-ray study; T = 296 K; mean (C-C) = 0.003 Å; R factor = 0.046; wR factor = 0.134; data-to-parameter ratio = 21.3.In the title compound, C 15 H 15 N 3 O 2 S, the fused ring system is close to planar, the largest deviation from the mean plane being 0.030 (2) Å , and makes a dihedral angle of 48.84 (9) with the benzene ring belonging to the methylbenzenesulfonamide moiety. In the crystal, molecules are connected through N-HÁ Á ÁN hydrogen bonds and weak C-HÁ Á ÁO contacts, forming a two-dimensional network parallel to (001). Related literature ExperimentalCrystal data