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.
POTENTIAL BILE ACID METABOLITES. XI. SYNTHESES OF STEREOISOMERIC 7,12-DIHYDROXY-5α-CHOLANIC ACIDS
Iida, Takashi,Momose, Toshiaki,Chang, Frederic C.,Nambara, Toshio
, p. 1934 - 1938 (2007/10/02)
Three new compounds, 7α,12β-, 7β,12α-, and 7β,12β-dihydroxy-5α-cholanic acids, were synthesized.The principal reactions employed were 1) selective acylation at C-7 of a 7α,12α-dihydroxy ester with the propionic anhydride-4-dimethylaminopyridine system, 2) potassium superoxide-18-crown-6 ether inversion of the 7α-hydroxyl group, and 3) stereoselective reduction of the 12-ketones with the sodium borohydride-palladium chloride system and tert-butylamine-borane complex.High-performance liquid chromatography was of key impotance in characterizing the compounds and determining their purity.Keywords-- bile acid; allobile acid; 7,12-dihydroxy-5-α-cholanic acid; selective acylation; potassium superoxide-18-crown-6 ether reaction; sodium borohydride-palladium chloride reduction; tert-butylamine-borane complex reduction; HPLC