反应详情

温度

62 °C

A solution of 0.234 g (0.842 mmol) of ferrous sulfate heptahydrate, 3 ml of water, and 0.293 g (3.05 mmol) of methanesulfonic acid is added to a mixture of 5.00 g (29.0 mmol) of 1-oxyl-2,2,6,6-tetramethylpiperidin-4-ol, 45 ml of acetonitrile, and 32 ml of cyclohexane, which has been heated to 62° C. A solution of 8.07 g (119 mmol) of 50% aqueous hydrogen peroxide is added dropwise over 2.25 hours to the reaction mixture while the temperature is maintained at reflux. A solution of 0.069 g of ferrous sulfate heptahydrate and 0.188 g of methanesulfonic acid in 2 ml of water is added to the reaction mixture 2 hours after the peroxide addition is started. A solution of 0.065 g of ferrous sulfate heptahydrate and 0.108 g of methanesulfonic acid in 1 ml of water is added to the reaction mixture 3.5 hours after the peroxide addition is started. After a total reaction time of 4.5 hours at reflux, the reaction mixture is allowed to cool. Excess peroxide is quenched with aqueous sodium sulfite solution. The aqueous layer is extracted with a 2:1 mixture of acetonitrile and cyclohexane, and the combined organic layers are washed with sodium hydroxide solution. To the organic layer are added 6 ml of t-butyl alcohol, 6 ml of water, 0.4 g of sodium hydroxide, and 0.70 g of sodium borohydride. The mixture is stirred for 3 hours, and the aqueous layer is extracted with ethyl acetate. The combined organic layers are washed with aqueous citric acid, aqueous sodium bicarbonate, and then concentrated. Purification by flash chromatography with 1:1 heptane-ethyl acetate affords 5.10 g (69% yield) of the title compound as a light yellow syrup, GC assay 93%.

1. temperatureis maintained
2. temperatureat reflux
3. temperatureAfter a total reaction time of 4.5 hours at reflux
4. temperatureto cool
5. customExcess peroxide is quenched with aqueous sodium sulfite solution
6. extractionThe aqueous layer is extracted with a 2:1 mixture of acetonitrile and cyclohexane
7. washthe combined organic layers are washed with sodium hydroxide solution
8. additionTo the organic layer are added 6 ml of t-butyl alcohol, 6 ml of water, 0.4 g of sodium hydroxide, and 0.70 g of sodium borohydride
9. extractionthe aqueous layer is extracted with ethyl acetate
10. washThe combined organic layers are washed with aqueous citric acid, aqueous sodium bicarbonate
11. concentrationconcentrated
12. customPurification by flash chromatography with 1:1 heptane-ethyl acetate