反应详情

温度

80 °C

A mixture of ethyl 6,8-dichloro-7-hydroxychroman-4-carboxylate (2.50 g, 8.59 mmol), tert-butyl 4-fluoro-3-nitrobenzoate (2.20 g, 9.12 mmol) and potassium carbonate (1.8 g, 13 mmol) in 50 mL of NMP was degassed with argon for 10 minutes and was heated at 80° C. overnight. After stirring overnight the reaction mixture was cooled to ambient temperature and diluted with 600 mL of water. The pH was adjusted to 1-2 with 1 N HCl and the resulting solids were collected by filtration. The solids were dissolved in ethyl acetate and the solution was washed with brine, dried over sodium sulfate, filtered and concentrated. The crude product was purified by flash column chromatography, eluting with 20% ethyl acetate in hexanes to give ethyl 7-(4-(tert-butoxycarbonyl)-2-nitrophenoxy)-6,8-dichlorochroman-4-carboxylate (2.74 g, 62.3% yield) as an oil.

1. customwas degassed with argon for 10 minutes
2. temperaturewas cooled to ambient temperature
3. additiondiluted with 600 mL of water
4. filtrationthe resulting solids were collected by filtration
5. dissolutionThe solids were dissolved in ethyl acetate
6. washthe solution was washed with brine
7. dry with materialdried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated
10. customThe crude product was purified by flash column chromatography
11. washeluting with 20% ethyl acetate in hexanes