938061-94-0

938061-93-9

938061-94-0

Synthesis of 4-bromo-3-methoxy-1H-indazole (CLXXXVI): To a stirred mixed solution of ethyl 4-bromo-3-methoxy-indazole-1-carboxylate (CLXXXV, 1.27 g, 4.14 mmol) in tetrahydrofuran (THF, 28 mL) and water (H2O, 9 mL) was added lithium hydroxide (LiOH, 397 mg, 16.6 mmol). The reaction mixture was stirred under reflux conditions for 2 hours, followed by continued stirring at room temperature for 15 hours. After completion of the reaction, the mixture was concentrated. The residue was diluted with ethyl acetate (EtOAc, 50 mL), washed sequentially with 1 M hydrochloric acid (HCl) and saturated brine (brine), dried over anhydrous magnesium sulfate (MgSO4), filtered and concentrated to afford 4-bromo-3-methoxy-1H-indazole (CLXXXVI) as an off-white solid in 98% yield. The obtained product was directly used in the next reaction without further purification.