反应详情

To a solution of 1.84 g (0.028 mole) of potassium hydroxide in 38 ml of ethanol and 10 ml of water was added 6.76 g (0.026 mole) of 2-hydroxymethyl-3-hydroxy-6-(trimethylacetoxymethyl)-4-pyrone, and the resulting mixture heated to 50°. An 8.3 g (0.03 mole) portion of ethyl 6-iodohexanoate was then added and the resulting clear solution heated at reflux for 7 hr under a nitrogen atmosphere. Removal of the ethanol under reduced pressure left a residue which was dissolved in methylene chloride. The organic solution was washed successively with aqueous NaHCO3 and saturated brine, was dried over magnesium sulfate, and was evaporated to afford a viscous oil. This material was chromatographed on silica gel eluting with ethyl acetate to give 2.9 g (27%) of oily product, 2-hydroxy-3-(5-carboethoxypentyloxy)-6-(trimethylacetoxymethyl)-4-pyrone. NMR (CDCl3): δ1.22 (3H, t, J = 7 Hz), 1.23 (9H, s), 2.30 (2H, t, J = 5.5 Hz), 6.32 (1H, s).

1. temperaturethe resulting mixture heated to 50°
2. temperaturethe resulting clear solution heated
3. temperatureat reflux for 7 hr under a nitrogen atmosphere
4. customRemoval of the ethanol under reduced pressure
5. waitleft a residue which
6. dissolutionwas dissolved in methylene chloride
7. washThe organic solution was washed successively with aqueous NaHCO3 and saturated brine
8. dry with materialwas dried over magnesium sulfate
9. customwas evaporated
10. customto afford a viscous oil
11. customThis material was chromatographed on silica gel eluting with ethyl acetate