Process and intermediates for the synthesis of vitamin D.sub.3
申请人:Hoffmann-La Roche Inc.
公开号:US04310467A1
公开(公告)日:1982-01-12
The present disclosure is directed to a process and intermediates for the synthesis of Vitamin D.sub.3 metabolites such as 1,25-dihydroxycholecalciferol, 25-hydroxycholecalciferol and 24R,25-dihydroxycholecalciferol from 17-keto steroids via intermediates having the natural steroid configuration at the 20-position. These novel intermediates are prepared from 17-keto steroids by reaction with ethyltriphenylphosphonium halides followed by reaction with formaldehyde to form comounds having the natural steroid configuration at the 20-position and which are suitable substrates for the preparation of the aforementioned Vitamin D.sub.3 metabolites.
Stereoselective Introduction of Steroid Side Chains at C (17) and C (20)
作者:Andrew D. Batcho、Donald E. Berger、Stephen G. Davoust、Peter M. Wovkulich、Milan R. Uskokovi?
DOI:10.1002/hlca.19810640546
日期:1981.7.22
(17) and C (20)) introduction of steroid side chains which are suitably functionalized for further elaboration is presented. The ene reaction of (17 Z)-ethylidene steroids, which are readily obtained from 17-keto steroids via a Wittigreaction, with various enophiles such as formaldehyde and acrylate esters leads to useful intermediates which contain the natural steroid configuration at C (20). Catalytic
Short-step stereoselective synthesis of 2α,3α,22-triacetoxy-23,24-dinor-5α-cholan-6-one: key intermediate for the preparation of 24-norbrassinolide, dolicholide and dolichosterone
作者:Braja G. Hazra、Vandana S. Pore、Padmakar L. Joshi
DOI:10.1039/p19930001819
日期:——
A stereoselectivesynthesis of 6-oxo-23,24-dinor-5α-cholan-2α,3α,22-triyl triacetate 9 was achieved in 44% overall yield in nine steps starting from 3β-hydroxyandrost-5-en-17-one 8. The important features of this synthesis are the modified Wittig reaction on the 17-oxo steroid 8 and the stereospecific generation of the chiral centre at C-20 by a resin-catalysed ene reaction on (Z)-3β, p-tolylsulfonyloxypregna-5
Resin catalysed ene reaction on 3β-toluene--sulfonoxy-(Z)-pregna-5,17(20)-diene : Synthesis of (20s)-6β-methoxy-3α,5-cyclo-5α-pregnane-20-carboxyaldehyde
作者:Braja G. Hazra、P.L. Joshi、V.S. Pore
DOI:10.1016/s0040-4039(00)97031-x
日期:1990.1
Synthesis of 16-substituted 23,24-dinorcholane derivatives
作者:R. P. Litvinovskaya、S. V. Drach、V. A. Khripach
DOI:10.1134/s1070428006010052
日期:2006.1
16-Substituted 22.24-dinorcholanes with variously modified A and B rings were synthesized starting from 17-oxo steroids through 17-ethylidene derivatives via ene reaction and subsequent transformations at the Delta(16)-bond.