反应详情

温度

0 °C

The crude ester from step D was dissolved in a mixture of MeOH (20 mL), THF (20 mL), and H2O (5 mL). To this was added 10M NaOH (2.3 mL, 23 mmol). After stirring for 3 hours, the solution was cooled to 0° C., and HOAc (1.5 mL) was added dropwise. The solution was partly concentrated to remove the THF and MeOH, and the product was then extracted into EtOAc. The organic layer was washed with H2O and brine. After drying (MgSO4), the solution was filtered and evaporated to give a pale orange solid. The product was stirred vigourously with a mixture of isopropanol (30 mL) and H2O (3 mL) to give the title compound as an off-white amourphous solid (2.6 g). mp=193°-196° C. (dec).

1. concentrationThe solution was partly concentrated
2. customto remove the THF and MeOH
3. extractionthe product was then extracted into EtOAc
4. washThe organic layer was washed with H2O and brine
5. dry with materialAfter drying (MgSO4)
6. filtrationthe solution was filtered
7. customevaporated
8. customto give a pale orange solid