反应详情

温度

110 °C

0.81 g(4.5 mmol) of 3,4-dihydroxycinnamic acid and 0.18 g (4.5 mmol) of sodium hydroxide were dissolved into 40 ml of methanol. Residues obtained after distillating in methanol dissolved into 70 ml of N,N-dimethylformamide and 0.65 g (4.05 mmol) of chlorokojic acid prepared in the Reference Example was added thereto. The resulting mixture was heated with stirring for 2 hours in an oil bath of 110° C. After distillating the solvent, the residue was dissolved in 300 ml of ethyl acetate. The ethyl acetate solution was washed with 5% hydrochloric acid and distilled water, dried over magnesium sulfate, decolored with active charcoal and filtered. The filtrate was concentrated to give 0.66 g(48.8%) of 2-(3,4-dihydroxycinnamoyl) oxymethyl-5-hydroxy-4H-pyran-4-one as a solid.

1. customResidues obtained
2. additionwas added
3. temperatureThe resulting mixture was heated
4. washThe ethyl acetate solution was washed with 5% hydrochloric acid
5. distillationdistilled water
6. dry with materialdried over magnesium sulfate
7. filtrationfiltered
8. concentrationThe filtrate was concentrated