反应详情

To a solution of Example 332A (13 g, 50.9 mmol) in tetrahydrofuran (150 mL) was added a 2.5 M solution of n-butyllithium in hexanes (30.5 mL, 76.4 mmol) dropwise at about −78° C. Then a solution of N,N-dimethylformamide (39.4 mL, 509.0 mmol) in tetrahydrofuran (40 mL) was added dropwise and the mixture was allowed to warm to ambient temperature. The mixture was poured into water and was extracted with ethyl acetate. The combined organic extracts were washed with brine, dried over MgSO4, filtered, and evaporated in vacuum. The residue was re-dissolved in a mixture of tetrahydrofuran (15 mL) and methanol (150 mL) and sodium borohydride (2.6 g, 68.7 mmol) was added in portions at about 0° C. The reaction mixture was stirred at room temperature for about 2 hours, then the mixture was concentrated in vacuum, diluted with water, and extracted with ethyl acetate. The combined organic extracts were washed with brine, dried (MgSO4), filtered and evaporated under reduced pressure. The residue was purified by flash column chromatography on silica gel using hexane/ethyl acetate (2:1) as the mobile phase to give the above intermediate. MS (DCI/NH3): m/z 207 (M+H)+.

1. extractionwas extracted with ethyl acetate
2. washThe combined organic extracts were washed with brine
3. dry with materialdried over MgSO4
4. filtrationfiltered
5. customevaporated in vacuum
6. additionwas added in portions at about 0° C
7. concentrationthe mixture was concentrated in vacuum
8. additiondiluted with water
9. extractionextracted with ethyl acetate
10. washThe combined organic extracts were washed with brine
11. dry with materialdried (MgSO4)
12. filtrationfiltered
13. customevaporated under reduced pressure
14. customThe residue was purified by flash column chromatography on silica gel
15. customto give the above intermediate