反应详情

To a stirred mixture of 2-ethyl-3-hydroxy-4-pyrone (49 g, 0.35 mol) in methanol (600 ml) and sodium hydroxide (16 g, 0.4 mol) dissolved in water (50 ml) was added benzyl chloride (47.2 ml, 0.41 mol) dropwise at room temperature. After heating under reflux for 48 hours the reaction mixture was cooled, filtered and the filtrate rotary evaporated to provide an oil. The oil was extracted with dichloromethane (300 ml), the solution washed with 5% w/v sodium hydroxide solution (3×250 ml) and water (3×250 ml), then dried over anhydrous sodium sulphate, filtered and rotary evaporated to provide an oil which was dissolved in diethyl ether and crystallized by coating with liquid nitrogen. Recrystallization from diethyl ether gave the title compound as colourless crystals (52.5 g, 65%), m.p. 33°-34° C.

1. temperatureAfter heating
2. temperatureunder reflux for 48 hours the reaction mixture
3. temperaturewas cooled
4. filtrationfiltered
5. customthe filtrate rotary evaporated
6. customto provide an oil
7. extractionThe oil was extracted with dichloromethane (300 ml)
8. washthe solution washed with 5% w/v sodium hydroxide solution (3×250 ml) and water (3×250 ml)
9. dry with materialdried over anhydrous sodium sulphate
10. filtrationfiltered
11. customrotary evaporated
12. customto provide an oil which
13. customcrystallized by coating with liquid nitrogen
14. customRecrystallization from diethyl ether