反应详情

Under nitrogen, 46.7 g (1.168 mol) of sodium hydride (60% dispersion in paraffin) were added to 600 ml of tetrahydrofuran. At 35° C. a mixture of 125 g (1.008 mol) of difluoroethyl acetate and 88.7 g (1.010 mol) of ethyl acetate was added dropwise while the temperature was maintained at below 40° C. This was followed by further stirring at room temperature overnight. The reaction mixture was carefully poured into 1.7 L of ice-water and adjusted to pH 3 with sulphuric acid. The reaction mixture was extracted twice with 500 ml of methyl tert-butyl ether each time, the combined organic phases were washed twice with saturated sodium chloride solution, dried over sodium sulphate and concentrated at 40° C. and 150 mbar before distillation at 60 mbar (Vigreux column). The product was obtained at 85-87° C. as a colourless liquid (104 g, 62% of theory having a purity of >99% (GC)).

1. additionwas added dropwise while the temperature
2. temperaturewas maintained at below 40° C
3. extractionThe reaction mixture was extracted twice with 500 ml of methyl tert-butyl ether each time
4. washthe combined organic phases were washed twice with saturated sodium chloride solution
5. dry with materialdried over sodium sulphate
6. concentrationconcentrated at 40° C.
7. distillation150 mbar before distillation at 60 mbar (Vigreux column)
8. customThe product was obtained at 85-87° C. as a colourless liquid (104 g, 62% of theory