反应详情

To a stirred solution of 3-acetyl-5-bromo-2,4-dimethylfuran (0.8 g, 3.69 mmol) in dimethoxyethane (DME; 11 mL) was added water (4 mL), NaHCO3 (0.93 g, 11 mmol), 4-pyridineboronic acid [prepared according to the method of Fischer F. C. et al., J. Red. Trav. Chim. Pays-Bays, 1965, 84, 439.] (0.5 g, 4.06 mmol) and bis(triphenylphosphine)palladium(II)chloride (0.26 g, 0.37 mmol) at room temperature under nitrogen. The mixture was heated at reflux temperature for 8 hours, and cooled down to room temperature. 4-Pyridineboronic acid (0.5 g, 4.07 mmol) and bis(triphenylphosphine)palladium(II)chloride (1.48 g, 2.11 mmol) were additionally added to the reaction mixture, and heated at reflux temperature for 3.5 hours. After cooling, the reaction mixture was filtered through celite pad. The filtrate was diluted with ethyl acetate (50 mL), and the whole was washed with water (30 mL). The aqueous layer was extracted with ethyl acetate (30 mL), and the combined organic layers were washed with brine (50 mL), dried over MgSO4, and concentrated in vacuo. The resulting residue was purified by flash chromatography eluting with ethyl acetate-hexane (5:1) to give the title compound (0.25 g, 31% yield).

1. customprepared
2. customat room temperature
3. temperatureThe mixture was heated
4. temperatureat reflux temperature for 8 hours
5. temperatureheated
6. temperatureat reflux temperature for 3.5 hours
7. temperatureAfter cooling
8. filtrationthe reaction mixture was filtered through celite pad
9. additionThe filtrate was diluted with ethyl acetate (50 mL)
10. washthe whole was washed with water (30 mL)
11. extractionThe aqueous layer was extracted with ethyl acetate (30 mL)
12. washthe combined organic layers were washed with brine (50 mL)
13. dry with materialdried over MgSO4
14. concentrationconcentrated in vacuo
15. customThe resulting residue was purified by flash chromatography
16. washeluting with ethyl acetate-hexane (5:1)