反应详情

To a solution of the compound (641 mg, 1.70 mmol) obtained in Example 178b in tetrahydrofuran (10 mL) was slowly added dropwise a solution (1.85 mL, 2.041 mmol) of 1.1M lithium hexamethyldisilazide in tetrahydrofuran under ice-cooling. The reaction mixture was stirred under ice-cooling for 5 min, iodomethane (0.16 mL, 2.55 mmol) was added dropwise at the same temperature, and the mixture was further stirred for 5 min. The reaction mixture was acidified with 1N aqueous hydrochloric acid solution, and extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (carrier: silica gel, eluent: hexane-ethyl acetate) to give the title compound (378 mg, 57%) as a colorless oil.

1. temperaturecooling
2. temperaturecooling for 5 min
3. stirringthe mixture was further stirred for 5 min
4. extractionextracted with ethyl acetate
5. washThe extract was washed with saturated brine
6. dry with materialdried over magnesium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe residue was purified by silica gel column chromatography (carrier: silica gel, eluent: hexane-ethyl acetate)