反应详情

温度

145 °C

Dry 2-(3-methyl-6-formyl-2-carboxy-5-hydroxy-phenoxy)-3,5-dihydroxy-4-methyl-benzoic acid methyl ester (1 mmol) was added to acetic anhydride (15 ml) and the resulting mixture was refluxed for five hours at 145° C. The excess acetic anhydride was distilled out. The residue was added with crushed ice and then extracted with ethyl acetate. The combined extracts were washed successively with saturated NH4Cl solution and water, dried over anhydrous Na2SO4, concentrated and purified by column chromatography to afford 4-formyl-3,8-dihydroxy-1,9-dimethyl-11-oxo-11H-dibenzo[b,e][1,4]dioxepine-6-carboxylic acid methyl ester (30%).

1. distillationThe excess acetic anhydride was distilled out
2. additionThe residue was added with crushed ice
3. extractionextracted with ethyl acetate
4. washThe combined extracts were washed successively with saturated NH4Cl solution and water
5. dry with materialdried over anhydrous Na2SO4
6. concentrationconcentrated
7. custompurified by column chromatography