1753-61-3Relevant articles and documents
The Octant Rule VIII. Variable Temperature Circular Dichroism Spectra of α-Methyl- and Methoxyl-Substituted 5α-Cholestan-2- and -3-ones.
Lightner, D. A.,Eng, F. P. C.
, p. 189 - 207 (1980)
2α- and 2β-methyl- and methoxy-5α-cholestan-3-ones and 3α- and 3β-methyl- and methoxy-5α-cholestan-2-ones have been synthesized and their variable temperature circular dichroism spectra obtained and analyzed.Rotatory strength (R) values for α-axial and equatorial CH3 and OCH3 groups are determined by difference measurements with the parent ketone.The (small) equatorial CH3 R-values do not consistently follow the Octant Rule.Axial OCH3 groups do not obey the Octant Rule ("anti-octant" behavior) and impose a bathochromic shift on the C=O n-?* transition.Equatorial OCH3 groups do not consistently follow octant or "anti-octant" behavior.
Synthesis of N,N-bis[2-(2-pyridyl)ethyl]amino steroids and related compounds intended as chiral ligands for copper ions
Gonschior, Manuela,Koetteritzsch, Manuela,Rost, Matthias,Schoenecker, Bruno,Wyrwa, Ralf
, p. 2159 - 2182 (2000)
Compounds with the N,N-bis[2-(2-pyridyl)ethyl]amino structure (RPY2) are useful tridentate ligands for copper(I) ions, which can bind and activate oxygen from the atmosphere. For diastereoselective and enantioselective oxidation reactions, hitherto unknown chiral ligands possessing tripodal structures have been synthesized starting from homochiral steroids. The double Michael addition of primary steroidal amines and aminoalcohols to 2-vinyl pyridine was not very succesful. However, homochiral bidentate ligands with N-[2-(2-pyridyl)ethyl]amino steroid structure could be obtained by this procedure in most cases. New routes (acylation of the bidentate ligands with 2-pyridylacetic acid followed by BH3.THF reduction, or reductive amination of steroidal ketones, acylation and borane reduction) to the desired tridentate RPY2, also at sterically hindered positions, are described. In the last reaction sequence, 'mixed' tridentate ligands can also be obtained. Copper complexation and oxygen activation with these ligands are briefly discussed. Copyright (C) 2000 Elsevier Science Ltd.
Modification in the side chain of solomonsterol A: Discovery of cholestan disulfate as a potent pregnane-X-receptor agonist
Sepe, Valentina,Ummarino, Raffaella,D'Auria, Maria Valeria,Lauro, Gianluigi,Bifulco, Giuseppe,D'Amore, Claudio,Renga, Barbara,Fiorucci, Stefano,Zampella, Angela
, p. 6350 - 6362 (2012/09/05)
Seven synthetic analogues of the PXR (pregnane-X-receptor) potent natural agonist solomonsterol A were prepared by total synthesis. Their activity toward PXR was assessed by transactivation and RT-PCR assays. The study discloses cholestan disulfate (8) as a new, simplified agonist of PXR. By in vitro studies on hepatic cells we have demonstrated that this compound is a potent PXR agonist and functional characterization in human macrophages and hepatic stellate cells provided evidence that cholestan disulfate (8) has the ability to modulate the immune response triggered by bacterial endotoxin as well as to counter-activate hepatic stellate cell activation induced by thrombin. Because inhibition of immune-driven circuits might have relevance in the treatment of inflammation and liver fibrosis, the present data support the development of cholestan disulfate (8) in preclinical models of inflammatory diseases. The Royal Society of Chemistry 2012.
Atypical regioselective biohydrolysis on steroidal oxiranes by Aspergillus niger whole cells: Some stereochemical features
Bisogno, Fabricio R.,Orden, Alejandro A.,Pranzoni, Celeste Aguirre,Cifuente, Diego A.,Giordano, Oscar S.,Kurina Sanz, Marcela
, p. 643 - 652 (2008/02/04)
5,6-Epoxycholestan-3β-ol derivatives were hydrolyzed in a diastereoconvergent manner by growing and resting cells of several strains of Aspergillus niger, particularly A. niger ATCC 11394. These strains displayed opposite regioselectivity toward each isomer in an α and β epoxide mixture, thus, the nucleophilic attack took place at the less substituted and the most substituted carbon atom on each diasteromer, respectively. These biocatalysts opened trisubstituted oxiranes but were unable to hydrolyze the disubstituted oxiranes in the tested sterol derivatives. These findings suggest that A. niger strains possess another hydrolytic ability different from the commercial A. niger epoxide hydrolase (EH) that did not accept this kind of steroidal oxiranes as substrates.
Regioselective enzymatic acylation of vicinal diols of steroids
Silva, M. Manuel Cruz,Riva, Sergio,Sá E Melo, M. Luisa
, p. 3065 - 3073 (2007/10/03)
Monoacylated derivatives of a complete set of 2,3- and 3,4-vicinal diols of steroids were prepared by regioselective lipase-catalysed transesterification reactions. The enzymes displayed different selectivities towards the vicinal diols depending on the configuration of the hydroxyl groups.
AN ALTERNATIVE ROUTE TO 2α,3α-DIOLS FROM 2,3-UNSATURATED 5α-STEROIDS AVOIDING THE USE OF OSMIUM TETRAOXIDE
Cerny, Vaclav
, p. 2211 - 2217 (2007/10/02)
A method for preparation of 2α,3α-dihydroxy-5α-steroids from 2,3-unsaturated 5α-steroids without the use of OsO4 is described.It involves the sequence of epoxidation, cleavage of the oxirane ring by HI, acetylation, oxidative replacement of iodine by hydroxyl and alkaline hydrolysis (I-IV) without purification of the intermediates.The presence of a 6-keto group does not decrease the yields.The yields are comparable with those obtained by osmylation and the method can find general use, particularly in the synthesis of brassinolide analogs.
