[Br:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[N:5][N:6]2C(=O)C.Cl>CO>[Br:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[N:5][NH:6]2To a solution of the 1-(4-bromo-indazol-1-yl)-ethanone A (3.09 g, 12.9 mmol) in MeOH (50 mL) was added 6N aqueous HCl (30 mL) and the mixture was stirred at room temperature for 7 h. The MeOH was evaporated and the mixture partitioned between EtOAc (2×50 mL) and water (50 mL). The combined organic layers were washed with brine (50 mL), separated and dried (MgSO4). The solvent was removed by evaporation under reduced pressure to give 4-bromo-1H-indazole B (2.36 g, 93%).
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