80115-47-5Relevant academic research and scientific papers
Synthesis of 16-substituted 23,24-dinorcholane derivatives
Litvinovskaya,Drach,Khripach
, p. 27 - 35 (2006)
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 Δ16- bond. Pleiades Publishing, Inc
Stereoselective synthesis of (22R,23R,24S)-3β-Hydroxy-5-ene-22,23-dihydroxy-24-methyl-cholestane: A Brassinolide Intermediate from 16-Dehydropregnenolone Acetate
Hazra, Braja G.,Joshi, Padmakar L.,Bahule, Bharat B.,Argade, Narshinha P.,Pore, Vandana S.,Chordia, Mahendra D.
, p. 2523 - 2532 (2007/10/02)
A new synthesis of the important aldehyde 1 from easily available 16-Dehydropregnenolone acetate (16-DPA) in high yield is described.The aldehyde 1 is converted to triol 24, involving a stereoselective generation of all the four chiral centers in the brassinolide side chain.The important features of this synthesis is stereospecific generation of the acetate 14 through ene reaction using three different catalysts as well as regioselective wittig reaction on the acetoxy aldehyde 20.Conversion of triol 24 to brassinolide is known, hence this constitutes a formal total synthesis of brassinolide.
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
Hazra, Braja G.,Pore, Vandana S.,Joshi, Padmakar L.
, p. 1819 - 1822 (2007/10/02)
A streoselective synthesis of 6-oxo-23,24-dinor-5α-cholan-2α,3α,22-triyl triacetate 9 was achieved in 44percent 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-5,17(20)-diene 11.
Resin catalysed ene reaction on 3β-toluene-p-sulfonoxy-(Z)-pregna-5,17(20)-diene: Synthesis of (20s)-6β-methoxy-3 α,5-cyclo-5α-pregnane-20-carboxyaldehyde
Hazra, Braja G.,Joshi,Pore
, p. 6227 - 6230 (2007/10/02)
Conversion of 17-keto steroid 2 in to 17(Z) ethylidene steroid 3 was achieved in high yields using a modified procedure. Ene reaction on 4 with paraformaldehyde in presence of acetic anhydride using various cation exchange resins as catalyst afforded stereo specifically the C-22 acetate 5 in excellent yields. For the first time cation exchange resins have been used as catalysts in ene reaction. Compound 5 was converted to C-22 aldehyde 1 using simple reaction sequence.
Stereoselective Introduction of Steroid Side Chains at C(17) and C(20)
Batcho, Andrew D.,Berger, Donald E.,Davoust, Stephen G.,Wovkulich, Peter M.,Uskokovic, Milan R.
, p. 1682 - 1688 (2007/10/02)
A simple and efficient new method for the highly stereoselective (at C(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 read
