反应详情

To a solution of 9-fluoro-11β-hydroxyandrosta-1,4-diene-3,17-dione (3.18 g) in a mixture of dry dichloromethane (40 ml) and glacial acetic acid (40 ml) containing p-methoxybenzenethiol (5.6 g) is added boron trifluoride etherate (3.0 ml) and the resulting solution is stirred for 1.5 hours. It is then poured into water (500 ml) and extracted with chloroform. The chloroform extracts are combined, washed with saturated sodium bicarbonate solution and water, dried (MgSO4) and concentrated in vacuo to a syrupy residue. This is absorbed on a column of silica gel (50 g) made up in chloroform-hexane (1:1) and the column is eluted successively with chloroform-hexane (1:1), chloroform and chloroform-ethyl acetate mixtures (95:5 and 90:10) to elute successively p-methoxybenzenethiol contaminated with some steroidal impurities, the title compound (3.0 g), a small amount of an undentified compound and unreacted starting material (1.0 g). The 3.0 g of material is refluxed with ethyl acetate (30 ml), cooled and filtered to leave the analytical specimen (dried at 0.3 mm of Hg, 100° C., 18 hours) of the title compound (2.8 g), melting point 209°-211° C., with consistent spectral data.

1. extractionextracted with chloroform
2. washwashed with saturated sodium bicarbonate solution and water
3. dry with materialdried (MgSO4)
4. concentrationconcentrated in vacuo to a syrupy residue
5. customThis is absorbed on a column of silica gel (50 g)
6. washthe column is eluted successively with chloroform-hexane (1:1), chloroform and chloroform-ethyl acetate mixtures (95:5 and 90:10)
7. washto elute successively p-methoxybenzenethiol
8. temperatureThe 3.0 g of material is refluxed with ethyl acetate (30 ml)
9. temperaturecooled
10. filtrationfiltered
11. customto leave
12. dry with materialthe analytical specimen (dried at 0.3 mm of Hg, 100° C., 18 hours) of the title compound (2.8 g), melting point 209°-211° C.