反应详情

Into a solution of tert-butyl 2,4-difluoronicotinate (0.95 g, 4.4 mmol) in THF (15 mL) at −78° C. was added a solution of LDA in heptane (1.5 M×3.5 mL, 5.3 mmol) dropwise. The mixture was stirred for 10 min. Then a solution of dibromotetrachloroethane (1.86 g, 5.7 mmol) in THF (4.0 mL) was added dropwise. After 15 min, the temperature was allowed to rise to room temperature slowly. The reaction was quenched with saturated NH4Cl. The mixture was extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate and evaporated to give a residue, which was purified by silica chromatography (5-50% dichloromethane in hexanes) to give tert-butyl 5-bromo-2,4-difluoronicotinate (0.55 g, 42%).

1. waitAfter 15 min
2. customto rise to room temperature
3. customThe reaction was quenched with saturated NH4Cl
4. extractionThe mixture was extracted with ethyl acetate
5. dry with materialThe combined organic layers were dried over sodium sulfate
6. customevaporated
7. customto give a residue, which
8. customwas purified by silica chromatography (5-50% dichloromethane in hexanes)