Synthesis of 7- and 12-hydroxy- and 7,12-dihydroxy-3-keto-5β-cholan-24-oic acids by reduction of 3,7-, 3,12- and 3,7,12-oxo derivatives
摘要:
7alpha-, 12alpha-, 12beta-Hydroxy and 7alpha,12alpha- and 7alpha,12beta-dihydroxy-3-ketocholanoic acids were prepared in satisfactory yields protecting the 3-keto group as dimethyl ketal and subsequent reduction with sodium borohydride of the corresponding 7- and 12-oxo functionalities. The same procedure gave also 3,12-diketo-7alpha-hydroxy-cholanoic acid.
Spontaneous ketalization of 3-keto-5β-cholanic acids in methanol
摘要:
The formation of 3-dimethyl ketals of 3-ketocholanic acids in methanol is described. The dependence of this unexpected behaviour on pKa of the cholanic acids is also reported.