反应详情

To a N,N-dimethylformamide (200 ml) solution of the 2,2-dimethyl-1,3-dioxan-5-ol (7.1 g, 0.054 mol) obtained in the step (9a), sodium hydride, in oil (2.81 g, 0.064 mol as the content was regarded as 55%) was added at 0° C. and stirred. After benzyl bromide (12.9 ml, 0.108 mol) and tetrabutylammonium iodide (220 mg, 0.001 mol) were added at the same temperature to the mixture, the mixture was stirred at room temperature for 1.5 hours. Water was added to the reaction mixture, which was then extracted with ethyl acetate three times. Organic layers were combined, washed five times with water and once with a saturated saline solution, dried over anhydrous sodium sulfate, and filtered. After NH silica gel was added, the resultant mixture was concentrated and purified by silica gel column chromatography (elution solvent: heptane, heptane/ethyl acetate=9/1, 4/1, ethyl acetate) to obtain the title compound (6.5 g, 54.5%) as a colorless oil.

1. additionwas added at 0° C.
2. stirringthe mixture was stirred at room temperature for 1.5 hours
3. extractionwas then extracted with ethyl acetate three times
4. washwashed five times with water
5. dry with materialonce with a saturated saline solution, dried over anhydrous sodium sulfate
6. filtrationfiltered
7. additionAfter NH silica gel was added
8. concentrationthe resultant mixture was concentrated
9. custompurified by silica gel column chromatography (elution solvent: heptane, heptane/ethyl acetate=9/1, 4/1, ethyl acetate)