反应详情

To a stirred solution of 6-bromo-1-ethyl-1H-indazole-4-carboxylic acid methyl ester (700 mg, 2.47 mmol) in THF (35 mL) was added a solution of LiOH.H2O (312 mg, 7.42 mmol) in water (15 mL) and the mixture was stirred at RT for 4 h. The reaction mixture was concentrated under reduced pressure, diluted with water (30 mL) and washed with EtOAc (2×25 mL). The aqueous layer was acidified (pH ˜5) with 1N HCl. The precipitated solid was collected by filtration and dried to furnish 6-bromo-1-ethyl-1H-indazole-4-carboxylic acid as a white solid (450 mg, 68%).

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. additiondiluted with water (30 mL)
3. washwashed with EtOAc (2×25 mL)
4. filtrationThe precipitated solid was collected by filtration
5. customdried