反应详情

A mixture of 4-bromo-2,2,6,6-tetramethyl-3,5-heptanedione (α-bromo-dipivaloylmethane; 1.42 g, 5.40 mmol), thiourea(451.8 mg, 5.94 mmol) and ethanol(15 mL) was refluxed for 2 hours. After the reaction mixture was cooled to room temperature, it was poured into saturated aqueous sodium hydrogen carbonate and extracted with ethyl acetate. After the ethyl acetate layer was washed successively with water and brine, dried over anhydrous sodium sulfate, the residue obtained by evaporation of the solvent under reduced pressure was crystallized by dichloromethane/n-hexane to give the title compound(1.23 g, 94.5%) as a white crystal.

1. temperaturewas refluxed for 2 hours
2. extractionextracted with ethyl acetate
3. washAfter the ethyl acetate layer was washed successively with water and brine
4. dry with materialdried over anhydrous sodium sulfate
5. customthe residue obtained by evaporation of the solvent under reduced pressure
6. customwas crystallized by dichloromethane/n-hexane