反应详情

温度

0 °C

A solution of ethyl ester 4b (250 mg, 0.846 mmol) in THF (5 mL) was cooled to 0° C. and 1 M LiOH (2.12 mL, 2.12 mmol) was added. The mixture stirred at 0° C. for 30 min followed by stirring at rt for 2 h. The THF was removed in vacuo and the remaining aqueous solution diluted with deionized H2O to a total volume of 8 mL. The aqueous mixture was extracted with Et2O (3×) and cooled to 0° C. 2 M HCl was added to obtain pH=3 and the mixture extracted with EtOAc (3×). The combined EtOAc extracts were washed with brine, dried over MgSO4 and filtered through a Celite plug capped with a layer of MgSO4. The solution was concentrated to give the title compound 5b as brittle ivory foam crushed to an ivory solid; 136 mg, 60%, MS m/z 266.0 (ESI−, M−1).

1. stirringby stirring at rt for 2 h
2. customThe THF was removed in vacuo
3. additionthe remaining aqueous solution diluted with deionized H2O to a total volume of 8 mL
4. extractionThe aqueous mixture was extracted with Et2O (3×)
5. temperaturecooled to 0° C
6. addition2 M HCl was added
7. customto obtain pH=3
8. extractionthe mixture extracted with EtOAc (3×)
9. washThe combined EtOAc extracts were washed with brine
10. dry with materialdried over MgSO4
11. filtrationfiltered through a Celite plug
12. customcapped with a layer of MgSO4
13. concentrationThe solution was concentrated