反应详情

To a cooled (0° C.) solution of the product of step C (835 mg; 1.78 mmol) lithium hydroxide (85 mg; 3.56 mmol) in 15 mL of a 4:1 mixture of tetrahydrofuran-water was added a 30% aqueous solution of hydrogen peroxide. After 5 min, the solution was warmed to ambient temperature and stirred for 5 h. The reaction mixture was poured into a 10% aqueous solution of sodium sulfite and then acidified to pH 3 with 1 N hydrochloric acid. The aqueous solution was extracted three times with ethyl acetate. The organic phase was washed with brine, dried (MgSO4), filtered, concentrated in vacuo and the crude acid was purified on silica gel (30% ethyl acetate/hexane with 1% acetic acid) which furnished 520 mg of the title compound.

1. extractionThe aqueous solution was extracted three times with ethyl acetate
2. washThe organic phase was washed with brine
3. dry with materialdried (MgSO4)
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customthe crude acid was purified on silica gel (30% ethyl acetate/hexane with 1% acetic acid) which