反应详情

温度

15 °C

A solution of chromium trioxide (42.6 g CrO3, 426 mmol) in water (40 mL) was diluted with acetic acid (350 mL). The solution was cooled to 15° C. and the product from Example 4A (27 g, 160 mmol) was added dropwise. The solution was left to stand at room temperature overnight. Ethanol (20 mL) was added to destroy the excess of CrO3. The mixture was heated at 50° C. for 15 minutes and then concentrated under reduced pressure. The residue was suspended in water, acidified to pH 2 and extracted 3 times with ether. The ethereal solution was concentrated and the residue was dissolved in hexanes. The organic solution is decanted from the green tar and concentrated under reduced pressure. The residue was dissolved in 10% aqueous NaOH and neutral impurities were extracted with ether (discarded). The aqueous phase was acidified to pH 2 and extracted with hexanes, dried with Na2SO4, concentrated, cooled and filtered to give 10.9 g of title compound (crystals melting point: 50-53° C.).

1. waitThe solution was left
2. customto destroy the excess of CrO3
3. temperatureThe mixture was heated at 50° C. for 15 minutes
4. concentrationconcentrated under reduced pressure
5. extractionextracted 3 times with ether
6. concentrationThe ethereal solution was concentrated
7. dissolutionthe residue was dissolved in hexanes
8. customThe organic solution is decanted from the green tar
9. concentrationconcentrated under reduced pressure
10. dissolutionThe residue was dissolved in 10% aqueous NaOH
11. extractionneutral impurities were extracted with ether (discarded)
12. extractionextracted with hexanes
13. dry with materialdried with Na2SO4
14. concentrationconcentrated
15. temperaturecooled
16. filtrationfiltered