14772-92-0Relevant articles and documents
Potential bile acid metabolites. XXI. A new synthesis of allochenodeoxycholic and allocholic acids
Iida,Nishida,Chang,Niwa,Goto,Nambara
, p. 763 - 765 (1993)
A new method for the preparation of allochenodeoxycholic and allocholic acids is described. The key steps in the synthesis are 1) simultaneous oxidation-dehydrogenation reaction of 3α-hydroxy 5β-bile acid formyl esters with iodoxybenzene catalyzed by benzeneseleninic anhydride, 2) reductive allomerization at C-5 of the 1,4-dien-3-oxo bydroxy acids with lithium/liq. ammonia, and 3) subsequent reduction of the resulting 3-oxo 5α-compounds with K-Selectride.
Allomerization of cholic acid and conversion to petromyzonol
Zhu, Xingpei,Amouzou, Etchri,McLean, Stewart
, p. 2447 - 2449 (2007/10/02)
Petromyzonol, a rare bile substance, has been prepared from an abundant starting material, cholic acid.The critical conversion, the inversion of the configuration at C-5, was accomplished by oxidizing a suitably protected derivative of cholic acid to a 1,4-dien-3-one, which was then stereoselectively reduced to methyl allocholate.In a single oxidation step, the 3-hydroxy steroid was converted to the dienone by Barton's procedure using a catalytic amount of benzeneseleninic anhydride and m-iodoxybenzoic acid as the stoichiometric oxidant.The stereoselective reduction employed two steps: hydrogenation of the dienone to the saturated ketone (5α) in the presence of the Wilkinson catalyst, followed by reduction of the ketone with K-Selectride.Finally, methyl allocholate was reduced to petromyzonol with lithium aluminum hydride.
A convenient synthesis of 3-keto bile acids by selective oxidation of bile acids with silver carbonate-Celite
Tserng
, p. 501 - 504 (2007/10/14)
-
