反应详情

To a −78° C. solution of the product of Example 45A (6.0 g, 20.6 mmoles) in THF (50 mL) was added a solution of lithium bis(trimethylsilyl)amide (1.0 M in THF, 22.7 mmoles). After 35 min, iodomethane (1.4 mL, 22.7 mmoles) was added and the reaction was slowly warmed to room temperature and stirred overnight. The reaction was quenched with aqueous sat. ammonium chloride and extracted with Et2O. The organic layer was then rinsed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by silica gel chromatography employing a solvent gradient (hexane→65:35 hexane:EtOAc). The resulting ester was hydrolyzed overnight at room temperature in THF (15 mL), H2O (10 mL), and EtOH (15 mL) with NaOH (2.5 g). The solution was concentrated under vacuum; the residue was dissolved in saturated ammonium chloride; and, the solution was extracted with ethyl acetate (3×). The combined ethyl acetate extracts were dried over sodium sulfate, filtered, and concentrated under vacuum to yield the title compound as a white solid.

1. customThe reaction was quenched with aqueous sat. ammonium chloride
2. extractionextracted with Et2O
3. washThe organic layer was then rinsed with brine
4. dry with materialdried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customThe crude product was purified by silica gel chromatography
8. waitThe resulting ester was hydrolyzed overnight at room temperature in THF (15 mL)
9. concentrationThe solution was concentrated under vacuum
10. dissolutionthe residue was dissolved in saturated ammonium chloride
11. extractionand, the solution was extracted with ethyl acetate (3×)
12. dry with materialThe combined ethyl acetate extracts were dried over sodium sulfate
13. filtrationfiltered
14. concentrationconcentrated under vacuum