反应详情

To a solution of methyl 5-fluoro-2H-indazole-4-carboxylate (4.50 g, 23.2 mmol) in ethyl acetate (93 mL) was 25 added trimethyloxonium tetrafluoroborate (4.46 g, 30.1 mmol) at room temperature, and the mixture was stirred for 5 hr. The reaction solution was diluted with water, and the mixture was extracted with ethyl acetate. The extract was dried over anhydrous sodium sulfate and the solvent was evaporated under reduced pressure. The residue was purified by flash silica gel column chromatography (ethyl acetate/hexane=1/2) to give the title compound (4.10 g, yield 85%).

1. customat room temperature
2. extractionthe mixture was extracted with ethyl acetate
3. dry with materialThe extract was dried over anhydrous sodium sulfate
4. customthe solvent was evaporated under reduced pressure
5. customThe residue was purified by flash silica gel column chromatography (ethyl acetate/hexane=1/2)