反应详情

A mixture of 2-fluoro-4-bromophenol (19.1 g), sodium hydroxide (6 g), ethyl iodide (46.8 g), tetra-n-butylammonium bromide (3.2 g), dichloromethane (250 cm3) and water (250 cm3) was stirred virgorously at the ambient temperature for 51/2 hours, then allowed to stand for a further 68 hours. The organic layer was separated and the aqueous layer was washed with dichloromethane; the combined organic layers were dired over anhydrous sodium sulphate. The solvent was removed by evaporation under reduced pressure at a bath temperature maintained below 40° C. The residual oil was purified by column chromatography on a silica gel support, eluting firstly with n-hexane and secondly with dichloromethane. The product-containing fractions were combined, washed with an aqueous solution of sodium metabisulphite, dried over anhydrous sodium sulphate and concentrated by evaporation under reduced pressure to give 4-bromo-2-fluorophenetole (15.2 g) as an oil. The product was shown by gas liquid chromatography to be 93% pure, and was used without further purification.

1. waitto stand for a further 68 hours
2. customThe organic layer was separated
3. washthe aqueous layer was washed with dichloromethane
4. customThe solvent was removed by evaporation under reduced pressure at a bath temperature
5. temperaturemaintained below 40° C
6. customThe residual oil was purified by column chromatography on a silica gel support
7. washeluting firstly with n-hexane and secondly with dichloromethane
8. washwashed with an aqueous solution of sodium metabisulphite
9. dry with materialdried over anhydrous sodium sulphate
10. concentrationconcentrated by evaporation under reduced pressure