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 vigorously 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 then dried 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 sodim 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. dry with materialthe combined organic layers were then dried over anhydrous sodium sulphate
5. customThe solvent was removed by evaporation under reduced pressure at a bath temperature
6. temperaturemaintained below 40° C
7. customThe residual oil was purified by column chromatography on a silica gel support
8. washeluting firstly with n-hexane and secondly with dichloromethane
9. washwashed with an aqueous solution of sodium metabisulphite
10. dry with materialdried over anhydrous sodim sulphate
11. concentrationconcentrated by evaporation under reduced pressure