反应详情

A mixture consisting of the ester (29.0 g, 0.0765 mol) of Step A, methanol (800 mL), water (50 mL) and potassium hydroxide (16.0 g, 0.29 mol) is refluxed for 4 hours. The reaction mixture is cooled to room temperature, concentrated and diluted with water (500 mL). The aqueous layer is washed with ether (2×200 mL) and made acidic with a 1:1 mixture of concentrated HCl and water to pH 2.71 is extracted with chloroform (4×300 mL) and the combined chloroform layers are washed once with water (2×300 mL), once with brine (300 mL), dried (MgSO4), filtered and concentrated to give 26.0 g of title compound, m.p. 163°-165° C.

1. temperatureis refluxed for 4 hours
2. concentrationconcentrated
3. additiondiluted with water (500 mL)
4. washThe aqueous layer is washed with ether (2×200 mL)
5. additionmade acidic with a 1:1 mixture of concentrated HCl and water to pH 2.71
6. extractionis extracted with chloroform (4×300 mL)
7. washthe combined chloroform layers are washed once with water (2×300 mL), once with brine (300 mL)
8. dry with materialdried (MgSO4)
9. filtrationfiltered
10. concentrationconcentrated