Bile acids. LXXIX. synthesis and reduction of 1,4-dien-3-ones of various bile acids
作者:Mohammed N. Iqbal、William H. Elliott
DOI:10.1016/0039-128x(89)90022-6
日期:1989.3
bile acids (IIa-d), their methyl esters (IIe-h), and their formylated derivatives (IIi-k) were synthesized and their reduction investigated by both catalytic and chemical methods as an alternative route to the synthesis of allo bile acids. Lithium-ammonia reduction proved to be the better method for the reduction of these 1,4-dien-3-ones producing the 3-keto- and 3 beta-hydroxy-allo bile acids (Vb-d)
Process for the preparation of pregnane derivatives
申请人:——
公开号:US20030181742A1
公开(公告)日:2003-09-25
A process for preparing pregnane derivatives represented by the formula (V),
1
which comprises the steps of:
reacting an alkali (earth) metal with a compound represented by the formula (I)
2
in the presence of ammonia or an amine, to obtain a compound represented by the formula (II);
3
protecting the hydroxy groups of the obtained compound, to obtain a compound represented by the formula (III);
4
protecting the 3-position carbonyl group of the obtained compound, to obtain a compound represented by the formula (IV);
5
and subjecting the obtained compound to solvolysis; and the compound (II).
Potential Bile Acid Metabolites. XXI. A New Synthesis of Allochenodeoxycholic and Allocholic Acids.
作者:Takashi IIDA、Shinji NISHIDA、Frederic C. CHANG、Toshifumi NIWA、Junichi GOTO、Toshio NAMBARA
DOI:10.1248/cpb.41.763
日期:——
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 hydroxy acids with lithium/liq. ammonia, and 3) subsequent reduction of the resulting 3-oxo 5α-compounds with K-Selectride.