An efficient synthesis of 4 beta- and 6 alpha-hydroxylated bile acids.
An efficient method for the preparation of 4 beta- and 6 alpha-hydroxylated bile acids has been developed. It involved a highly stereoselective acetoxylation at the 4 beta and 6 alpha positions of 3- and 7-oxo bile acids, respectively, with lead tetraacetate in the presence of boron trifluoride etherate in acetic acid. Reduction of the resulting alpha-acetoxy ketones with sodium borohydride or tert-butylamine borane complex, and alkaline hydrolysis, provided the desired bile acids in good yields.
Yoshimura
T
T
Faculty of Pharmaceutical Sciences, Higashi-Nippon-Gakuen University, Hokkaido, Japan.
Mahara
R
R
Kurosawa
T
T
Ikegawa
S
S
Tohma
M
M
D000085:Acetates; D019342:Acetic Acid; D001647:Bile Acids and Salts / Q000138:chemical synthesis*; D001880:Boranes; D001894:Borohydrides; D002793:Cholic Acids / Q000737:chemistry; D006801:Humans; D006900:Hydroxylation; D007659:Ketones / Q000737:chemistry; D015394:Molecular Structure; D009942:Organometallic Compounds; D010084:Oxidation-Reduction
D000085:Acetates; D001647:Bile Acids and Salts; D001880:Boranes; D001894:Borohydrides; D002793:Cholic Acids; D007659:Ketones; D009942:Organometallic Compounds; C021274:boron trifluoride; C025364:sodium borohydride; C029433:lead tetraacetate; C007036:cholanic acid; D019342:Acetic Acid