反应详情

A solution of 2-(4-acetonylphenoxymethyl)-5-benzyloxy-4H-pyran-4-one, ethylene ketal (2.0 g) in methanol was hydrogenated at ambient temperature and pressure over 10% palladium on carbon until absorption of hydrogen was complete. The catalyst was filtered off and the solvent removed in vacuo. The residue was dissolved in acetone (75 ml) and treated with 2N-hydrochloric acid solution (2 ml) and allowed to stand at room temperature for 2 h. The solvent was then removed in vacuo, the residue dissolved in ethyl acetate, washed with water (2×50 ml), brine (1×50 ml) and dried (magnesium sulphate). After filtration and evaporation of the solvent, the residue was purified by column chromatography on silica using methanol-chloroform (2:98) as eluent to give 2-(4-acetonylphenoxymethyl) -5-hydroxy-4H-pyran-4-one, (1.2 g).

1. customwas hydrogenated at ambient temperature
2. custompressure over 10% palladium on carbon until absorption of hydrogen
3. filtrationThe catalyst was filtered off
4. customthe solvent removed in vacuo
5. dissolutionThe residue was dissolved in acetone (75 ml)
6. additiontreated with 2N-hydrochloric acid solution (2 ml)
7. customThe solvent was then removed in vacuo
8. dissolutionthe residue dissolved in ethyl acetate
9. washwashed with water (2×50 ml), brine (1×50 ml)
10. dry with materialdried (magnesium sulphate)
11. filtrationAfter filtration and evaporation of the solvent
12. customthe residue was purified by column chromatography on silica