Summary 'I'he diethyl thioacetals of cholestanone 3, :I-ketocholanic acid and methyl 3-ketocholsnate have been prepared. The enol ethyl thioether of A4-cholestenone- 3 has been prepared. Hydrolysis of this coni- pound with alcoholic hydrochloric acid gave back A '-cholcsteiioiie-:1. :I. Hytlrogeriolysis of cholcstaiioiie-:3 thio- acetal with a niodified Kaney nickel catalyst in di- oxane gave cholestane. 1. Hydrogenolysis of methyl 3-ketocholanate thioacetal with a modified ...