反应详情

A solution of methyl 3α-acetoxy-6-bromo-7-keto-5β-cholanoate (10.0 g, 19.025 mmoles) in methanol (600 ml) was added to a solution of potassium hydroxide (24 g) in water (100 ml), dropwise, in 1 hour. The resulting mixture was left to react for 48 hours under argon atmosphere, with magnetic stirring. The reaction mixture was diluted with water (100 ml), acidified with 10% hydrochloric acid and extracted with chloroform (3×200 ml). The combined organic phases were washed with brine (1×50 ml) and dried over sodium sulfate. After evaporation of the solvent, the residue (7.7 g) was reacted with p-toluenesulfonic acid (0.5 g) in methanol (250 ml) under magnetic stirring for one night. The reaction mixture was concentrated under vacuum, taken up into chloroform (150 ml) and washed first water (3 x 30 ml), then with brine (1×50 ml). The organic phase was dried over sodium sulfate and concentrated under vacuum. The residue (8.0 g) was subjected to flash chromatography on silica, eluting with chloroform/methanol 98:2, to obtain 4.5 g of a pure product (56%).

1. waitThe resulting mixture was left
2. customto react for 48 hours under argon atmosphere, with magnetic stirring
3. extractionextracted with chloroform (3×200 ml)
4. washThe combined organic phases were washed with brine (1×50 ml)
5. dry with materialdried over sodium sulfate
6. customAfter evaporation of the solvent
7. customthe residue (7.7 g) was reacted with p-toluenesulfonic acid (0.5 g) in methanol (250 ml)
8. concentrationThe reaction mixture was concentrated under vacuum
9. washwashed first water (3 x 30 ml)
10. dry with materialThe organic phase was dried over sodium sulfate
11. concentrationconcentrated under vacuum
12. washeluting with chloroform/methanol 98:2