反应详情

A mixture of 3-hydroxy-4H-pyran-4-one (1.12 g), ethyl 2-bromoacetate (1.7 g) and potassium carbonate (1.4 g) in ethanol (30 ml) was stirred at 67° to 70° C. for 75 minutes. The reaction mixture was allowed to stand at room temperature. An insoluble substance was filtered off, and the filtrate was adjusted to pH 4 to 5 with conc. hydrochloric acid and the ethanol was removed. To the residue was added ethyl acetate, and the resultant mixture was washed with an aqueous solution saturated with sodium chloride and dried over magnesium sulfate. After removal of the solvent, the residue was chromatographed on silica gel (15 g) with an eluent (ethyl acetate:benzene=1:5) to give crystals of ethyl 2-(4-oxo-4H-pyran-3-yloxy)acetate, mp 58° to 60° C.

1. customto stand at room temperature
2. filtrationAn insoluble substance was filtered off
3. customthe ethanol was removed
4. additionTo the residue was added ethyl acetate
5. washthe resultant mixture was washed with an aqueous solution saturated with sodium chloride
6. dry with materialdried over magnesium sulfate
7. customAfter removal of the solvent
8. customthe residue was chromatographed on silica gel (15 g) with an eluent (ethyl acetate:benzene=1:5)