反应详情

Dimethyl formamide (100 ml) and tetrahydrofuran (300 ml) were placed in a 1000 ml three-neck round-bottom flask equipped with a thermometer, a mechanical stirrer, and a dropping funnel. An 80% dispersion of sodium hydride in oil (19.80 g, 0.66 mol) was added to form a gray suspension. The suspension was cooled in an ice-water bath. Methyl hydroxyisobutyrate (70.8 g, 0.60 mol) was dissolved in tetrahydrofuran (50 ml) and added slowly to the cooled sodium hydride suspension while the temperature was held below 15° C. The resulting suspension was stirred for one hour. Methyl iodide (freshly distilled, 108.75 g, 0.75 mol) in tetrahydrofuran (25 ml) was slowly added to the cooled suspension. The addition took 1.5 hours, during which the temperature was held below 15° C. The suspension was stirred and allowed to warm to room temperature for 15 hours. The suspension was poured into ethyl acetate (300 ml) and water (300 ml). The clear layers were separated and the aqueous phase was extracted with ethyl acetate (300 ml). The combined organic layers were decolorized with water (200 ml) containing sodium bisulfite (10 g). The organic phase was separated and dried over magnesium sulfate. The solvent was mostly removed by rotary evaporation (25 mm Hg, 30° C.). The resulting solution was distilled at atmospheric pressure and the product collected at 137°-146° C. The product was contaminated with DMF, but by NMR the yield of product was 48.8 g (61%).

1. customequipped with a thermometer, a mechanical stirrer, and a dropping funnel
2. customto form a gray suspension
3. temperatureThe suspension was cooled in an ice-water bath
4. customwas held below 15° C
5. distillationMethyl iodide (freshly distilled
6. addition108.75 g, 0.75 mol) in tetrahydrofuran (25 ml) was slowly added to the cooled suspension
7. additionThe addition
8. waittook 1.5 hours, during which
9. customwas held below 15° C
10. stirringThe suspension was stirred
11. additionThe suspension was poured into ethyl acetate (300 ml) and water (300 ml)
12. customThe clear layers were separated
13. extractionthe aqueous phase was extracted with ethyl acetate (300 ml)
14. additioncontaining sodium bisulfite (10 g)
15. customThe organic phase was separated
16. dry with materialdried over magnesium sulfate
17. customThe solvent was mostly removed by rotary evaporation (25 mm Hg, 30° C.)
18. distillationThe resulting solution was distilled at atmospheric pressure
19. customthe product collected at 137°-146° C