51231-23-3Relevant academic research and scientific papers
A convenient synthesis of the side-chain of sterols
Schmittberger,Uguen
, p. 29 - 32 (1996)
Potassium t-butoxide-induced Ramberg-Backlund rearrangement of chlorosulfones formed from a cyclopregnane-20-thiomethanol derivative has been shown to give Δ22-unsaturated steroids with high trans stereoselectivity.
(2,3)-WITTIG SIGMATROPIC REARRANGEMENTS IN STEROID SYNTHESIS. NEW STEREOCONTROLLED APPROACH TO STEROIDAL SIDE CHAINS AT C-20
Castedo, L.,Granja, J. R.,Mourino, A.
, p. 4959 - 4960 (1985)
A new method which is based on (2,3)-Wittig sigmatropic rearrengements for the stereocontrolled synthesis of functionalized three-carbon side chains on the basic tetracyclic steroidal system is described.
On the mechanism of the dyotropic expansion of hydrindanes into decalins
Fall, Yagamare,Gómez, Generosa,López, Carlos Silva,Nieto Faza, Olalla,Santalla, Hugo
supporting information, p. 1073 - 1079 (2022/02/16)
A combined computational/experimental approach has revealed key mechanistic aspects in a recently reported dyotropic expansion of hydrindanes into decalins. While computer simulations had already anticipated the need for acid catalysis for making this reaction feasible under the mild conditions used in the laboratory, this work places the dyotropic step not into the reaction flask but at a later step, during the work up instead. With this information in hand the reaction has been optimized by exploring the performance of different activating agents and shown to be versatile, particularly in steroid related chemistry due to the two scaffolds that this reaction connects. Finally, the scope of the reaction has been significantly broadened by showing that this protocol can also operate in the absence of the fused six-member ring.
NOVEL METHOD FOR SYNTHESIZING 25-OH CHOLESTEROL/CALCIFEDIOL FROM PHYTOSTEROL
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Page/Page column 18-19, (2020/11/23)
The present invention discloses novel method for synthesizing vegan 25-OH cholesterol/Calcifediol from inexpensive crude phytosterol. According to the method, Phytosterols are reacted to form corresponding i-steroid through tosylation and methanolysis. i-steroid on reductive ozonolysis to C-22 alcohol and conversion via C-22 tosylate to C-22 iodide in good yield. Coupling of C-22 tosylate with Grignard reagent of 4-bromo-2-methyl-2-[(trimethylsilyl)oxy] butane followed by deprotection yielded 25-OH cholesterol. In a process variant, nickel mediated conjugate addition of C-22 iodide to an electron deficient alkene ethyl acrylate and treating corresponding ester with methyl magnesium bromide as means of installing the side chain of 25-OH cholesterol in high yield. Further bromination reaction of 25-OH cholesterol diacetate followed by dehydrobromination using TBAF yielded 25-OH 7-dehydrocholesterol. Further photo reaction of 25-OH 7-dehydrocholesterol in to previtamin D3 using high or medium pressure mercury lamp and subsequent thermal reaction of previtamin D3 to 25-OH vitamin D3(Calcifediol) in good yield.
Synthesis of a Cholesterol Side-Chain Triazole Analogue via 'Click' Chemistry
Seck, Insa,Fall, Alioune,Lago, Carmen,Sène, Massène,Gaye, Mohamed,Seck, Matar,Gómez, Generosa,Fall, Yagamare
, p. 2826 - 2830 (2015/09/15)
An efficient preparation of a cholesterol analogue possessing a triazole ring is achieved starting from commercially available stigmasterol. The procedure is based on a [3+2] cycloaddition of a cholesterol possessing a side-chain terminal azide with a ter
Access to functionalized steroid side chains via modified Julia olefination
Izgu, Enver Cagri,Burns, Aaron C.,Hoye, Thomas R.
, p. 703 - 705 (2011/04/26)
Various functionalized steroidal side chains were conveniently accessed by a modified Julia olefination strategy using a common sulfone donor and an appropriate α-branched aldehyde acceptor. For the coupling of these hindered classes of reaction partners (and in contrast to typically observed trends), the benzothiazolyl(BT)-sulfone anion gave superior outcomes compared to the phenyltetrazolyl(PT)-sulfone anion.
Preparation of (25R)- and (25S)-26-functionalized steroids as tools for biosynthetic studies of cholic acids
Khripach, Vladimir A.,Zhabinskii, Vladimir N.,Konstantinova, Olga V.,Khripach, Natalya B.,Antonchick, Alexey V.,Antonchick, Andrey P.,Schneider, Bernd
, p. 551 - 562 (2007/10/03)
A new synthesis of both epimeric forms of 26-cholestanoic acids and 26-alcohols containing a 3β-hydroxy-Δ5- or a Δ4-3-keto-functionality in ring A is described starting from stigmasterol or (20S)-3β-acetoxy-pregn-5-en-20-carboxylic a
Synthesis of [26,27-2H6]brassinosteroids from 23,24-bisnorcholenic acid methyl ester
Antonchick, Andrey P.,Schneider, Bernd,Zhabinskii, Vladimir N.,Khripach, Vladimir A.
, p. 617 - 628 (2007/10/03)
A number of hexadeuterated brassinosteroids (BS) containing a hydroxy group at C-22 or a 22R,23R-diol function were prepared starting from 23,24-bisnorcholenic acid methyl ester for biosynthetic studies. Synthesis of the cyclic part was accomplished via t
Further studies on the synthesis of 24(S),25-epoxycholesterol. A new, efficient preparation of desmosterol
Spencer, Thomas A.,Li, Dansu,Russel, Jonathon S.,Tomkinson, Nicholas C. O.,Willson, Timothy M.
, p. 1919 - 1923 (2007/10/03)
Efforts to improve the synthesis of 24(S),25-epoxycholesterol (1) from stigmasterol (3) have included identification of 6α-hydroxy-i-steroid 11 as a byproduct from the ozonolysis of 9 and an attempt to effect conversion of sulfone 14 to diol 18 via Payne rearrangement and nucleophilic trapping of epoxide 25, which led instead to 27 and 28 (97% yield). A more efficient synthesis of 1 was achieved via coupling of cuprate 21 with allylic acetate 31 to give 73% of 16, in the most efficient conversion yet of a C22 intermediate to desmosterol (5) or its acetate 6.
Efficient, stereoselective synthesis of 24(s), 25-epoxycholesterol
Tomkinson, Nicholas C. O.,Willson, Timothy M.,Russel, Jonathon S.,Spencer, Thomas A.
, p. 9919 - 9923 (2007/10/03)
Efficient, stereoselective syntheses of 24(S), 25-epoxycholesterol (1) have been developed starting from cholenic acid (4) or stigmasterol (8), both featuring as the key step Sharpless asymmetric dihydroxylation of desmosterol acetate (2). This work permits preparation of gram quantities of 1 for further evaluation as a natural regulator of cholesterol metabolism, specifically, e.g., as a ligand for the LXRα. nuclear receptor.
