A solution of
50 g. (0.13 mole) of dihydrocholesterol (Note
1) in
500 cc. of benzene is added slowly with cooling (Note
2) to a solution of
68 g. (0.23 mole) of crystalline sodium dichromate,
50 cc. of glacial acetic acid, and
90 cc. of concentrated sulfuric acid in 300 cc. of water in a
3-l. flask. The mixture is agitated thoroughly in a shaking device or by efficient stirring (Note
3) for six hours at 25–30° (Note
4).
The
benzene solution is separated and washed twice with 100 cc. of water, once with
200 cc. of 5 per cent potassium hydroxide, and twice with water. If the solution is not colorless it is clarified with
1 g. of Norite. The
benzene is removed by distillation, and the resulting syrup is dissolved in
300 cc. of alcohol by heating. The solution on cooling deposits
cholestanone as well-formed needles. The yield of collected, washed, and air-dried material, m.p.
129–130°, is
41.5–42 g. (
83–84 per cent of the theoretical amount). The addition of 80 cc. of water to the filtrate gives about
2 g. of material melting at
125–126°.