反应详情

温度

70 °C

Intermediate 11 (2.98 g) in ethanol (25 ml) was treated with aqueous sodium hydroxide (2.5M, 18 ml) and the solution stirred at 70° C. for 3.5 h then allowed to cool. The material was concentrated in vacuo to remove the ethanol, then the aqueous phase was washed with ethyl acetate (30 ml). The aqueous phase was adjusted to pH1 by addition of aqueous hydrochloric acid (5M) and the desired acid was extracted into ethyl acetate (1×100 ml, 1×50 ml). The combined organic phases were washed with dilute aqueous sodium chloride, dried (Na2SO4), filtered and the solution concentrated in vacuo to give the title compound as a cream solid (2.54 g).

1. temperatureto cool
2. concentrationThe material was concentrated in vacuo
3. customto remove the ethanol
4. washthe aqueous phase was washed with ethyl acetate (30 ml)
5. additionThe aqueous phase was adjusted to pH1 by addition of aqueous hydrochloric acid (5M)
6. extractionthe desired acid was extracted into ethyl acetate (1×100 ml, 1×50 ml)
7. washThe combined organic phases were washed with dilute aqueous sodium chloride
8. dry with materialdried (Na2SO4)
9. filtrationfiltered
10. concentrationthe solution concentrated in vacuo