反应详情

To a suspension of 2,2,6,6-tetramethylpyran-3,5-dione (741 mg, 4.35 mmol) in chloroform (10 ml) is added phosphorus pentachloride (454 mg, 2.18 mmol), and the reaction is heated to reflux for 5 hours. Silica gel is added to the cooled crude reaction mixture, the solvent is evaporated under reduced pressure and the residue is purified by flash chromatography on silica gel to give 5-chloro-2,2,6,6-tetramethyl-6H-pyran-3-one (349 mg).

1. temperaturethe reaction is heated
2. temperatureto reflux for 5 hours
3. additionSilica gel is added to the
4. temperaturecooled crude
5. customreaction mixture
6. customthe solvent is evaporated under reduced pressure
7. customthe residue is purified by flash chromatography on silica gel