反应详情

To a stirred solution of methyl 6-bromo-1-isopropyl-3-methyl-1H-indazole-4-carboxylate (7.5 g, 24.11 mmol) in ethanol (400 mL) was added sodium hydroxide (1.45 g, 36.17 mmol) in water (60 mL) and the reaction mixture was stirred at reflux for 6 h. The reaction mixture was concentrated under reduced pressure and the residue was diluted with water (150 mL), and acidified with 2N HCl to pH˜2. The precipitated acid was collected by filtration, washed with ether (200 mL, and dried to afford 6-bromo-1-isopropyl-3-methyl-1H-indazole-4-carboxylic acid as an off white solid (6.85 g, 95.6%). LCMS (ES−): 294.9 [M−H].

1. temperatureat reflux for 6 h
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. additionthe residue was diluted with water (150 mL)
4. filtrationThe precipitated acid was collected by filtration
5. washwashed with ether (200 mL
6. customdried