反应详情

Dissolve 4-hydroxy-6-methyl-pyran-2-one (12.6 g, 100 mmol) in trifluoroacetic acid (50 ml). and add 7.8 g (100 mml) of acetyl chloride dropwise. Heat this mixture at reflux for 5 hours. Evaporate the reaction mixture under reduced pressure. Add 50 ml of water, extract with ethyl acetate (50 ml×3) and combine the organic layers. Wash with brine and dry (sodium sulfate). Chromatograph on silica gel, eluting with chloroform to provide 5.8 g (34.5 mmol) of 3-acetyl-4-hydroxy-6-methyl-pyran-2-one.

1. temperatureHeat this mixture
2. temperatureat reflux for 5 hours
3. customEvaporate the reaction mixture under reduced pressure
4. additionAdd 50 ml of water
5. extractionextract with ethyl acetate (50 ml×3)
6. washWash with brine
7. dry with materialdry (sodium sulfate)
8. washChromatograph on silica gel, eluting with chloroform