反应详情

A mixture of ethyl 2,5-dichloronicotinate (step 1, 10 g, 0.045 mol), tetrakis(triphenylphoshine)palladium (5.2 g, 4.5 mmol), trimethylboroxine (5.65 g, 0.045 mmol) and potassium carbonate (18.66 g, 0.16 mmol) in 1,4-dioxane (contain 10% water, 100 ml) was refluxed for 7 h under nitrogen atmosphere. The reaction mixture was cooled to room temperature and poured into water. The aqueous mixture was extracted with ethyl acetate. The organic extracts were dried over sodium sulfate and concentrated. The residue was purified by flush column chromatography on silica gel eluting with hexane/ethyl acetate (50/1 to 20/1) to afford 3.41 g (38%) of the title compound:

1. temperaturewas refluxed for 7 h under nitrogen atmosphere
2. extractionThe aqueous mixture was extracted with ethyl acetate
3. dry with materialThe organic extracts were dried over sodium sulfate
4. concentrationconcentrated
5. customThe residue was purified
6. customby flush column chromatography on silica gel eluting with hexane/ethyl acetate (50/1 to 20/1)