1258-35-1Relevant articles and documents
ON THE CONVERSION OF SUBSTITUTED EPOXIDES TO HALOHYDRINS
Caputo, Romualdi,Chianese, Maria,Ferreri, Carla,Palumbo, Giovanni
, p. 2011 - 2012 (1985)
Di- and trisubstituted steroidal epoxides are shown to be converted smoothly to halohydrins in high yield by triphenylphosphine-halogen complexes, under non-acidic and non-eliminating conditions.
HALOGENATED CHOLESTEROL ANALOGUES AND METHODS OF MAKING AND USING SAME
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Paragraph 0088; 0092-0094, (2020/05/12)
Provided herein are halogenated cholesterol analogues, including methods of making and using the same. Also provided are methods of making radiolabeled cholesterol analogues including admixing an epoxide with a fluorine-18 source under conditions to form a radiofluorinated cholesterol analogue.
Synthesis of the 8,19-Epoxysteroid Eurysterol A
Taspinar, ?mer,Wilczek, Tobias,Erver, Julian,Breugst, Martin,Neud?rfl, J?rg-Martin,Schmalz, Hans-Günther
supporting information, p. 4256 - 4260 (2020/03/23)
We report the first chemical synthesis of eurysterol A, a cytotoxic and antifungal marine steroidal sulfate with a unique C8?C19 oxy-bridged cholestane skeleton. After C19 hydroxylation of cholesteryl acetate, used as an inexpensive commercial starting material, the challenging oxidative functionalization of ring B was achieved by two different routes to set up a 5α-hydroxy-7-en-6-one moiety. As a key step, an intramolecular oxa-Michael addition was exploited to close the oxy-bridge (8β,19-epoxy unit). DFT calculations show this reversible transformation being exergonic by about ?30 kJ mol?1. Along the optimized (scalable) synthetic sequence, the target natural product was obtained in only 11 steps in 5 % overall yield. In addition, an access to (isomeric) 7β,19-epoxy steroids with a previously unknown pentacyclic ring system was discovered.
Synthetic study of strongylophorines: stereoselective construction of the characteristic lactone bridge
Oikawa, Yuya,Uchiyama, Daiki,Shirasawa, Takuya,Oikawa, Masato,Ishikawa, Yuichi
supporting information, p. 3949 - 3951 (2016/08/09)
Herein, we report an efficient construction of the lactone bridge of strongylophorine-2, which is a meroditerpenoid isolated from Strongylophora durissima and an inhibitor for HIF-1 transcriptional pathway. Starting from dehydroepiandrosterone acetate, the characteristic lactone has been constructed in 5.4% over 18 steps by employing, (1) modified oxy radical-mediated C–H functionalization at the C24 methyl group, and (2) four-step manipulation of C4 quaternary carbon stereogenic center. The lactone synthesized here is expected as a precursor for (8-desmethyl)strongylophorine-2 which is of particular interest in terms of structure–activity relationships in the inhibition of HIF-1 transcriptional pathway.
Sterol synthesis. Preparation and characterization of fluorinated and deuterated analogs of oxygenated derivatives of cholesterol
Li, Shengrong,Pang, Jihai,Wilson, William K.,Schroepfer Jr., George J.
, p. 33 - 71 (2007/10/03)
Oxygenated sterols, including both autoxidation products and sterol metabolites, have many important biological activities. Identification and quantitation of oxysterols by chromatographic and spectroscopic methods is greatly facilitated by the availability of authentic standards, and deuterated and fluorinated analogs are valuable as internal standards for quantitation. We describe the preparation, purification and characterization of 43 oxygenated sterols, including the 4β-hydroxy, 7α-hydroxy, 7β-hydroxy, 7-keto, and 19-hydroxy derivatives of cholesterol and their analogs with 25,26,26,26,27,27,27-heptafluoro (F7) and 26,26,26,27,27,27-hexadeuterio (d6) substitution. The 7α-hydroxy, 7β-hydroxy, and 7-keto derivatives of (25R)-cholest-5-ene-3β,26-diol (1d) and their 16,16-dideuterio analogs were also prepared. These d2-26-hydroxysterols and [16,16-2H2]-(25R)-cholest-5-ene-3β,26-diol (1e) were synthesized from [16,16-2H2]-(25R)-cholest-5-ene-3β,26-diol diacetate (2e), which can be prepared from diosgenin. The highly specific deuterium incorporation at C-16 in 1e and 2e should be useful in mass spectral analysis of 26-hydroxycholesterol samples by isotope dilution methods. The Δ5-3β,7α,26- and Δ5-3β,7β,26-triols were regioselectively oxidized/isomerized to the corresponding Δ4-3-ketosteroids with cholesterol oxidase. Also described are 5,6α-epoxy-5α-cholestan-3β-ol, its 5β,6β-isomer, cholestane-3β,5α,6β-triol, their F7 and d6 derivatives, and d3-25-hydroxycholesterol, which was prepared from 3β-acetoxy-27-norcholest-5-en-25-one (30). The 43 oxysterols and most synthetic intermediates were isolated in high purity and characterized by chromatographic and spectroscopic methods, including mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy. Detailed mass spectral assignments are presented, and 1H NMR stereochemical assignments are derived for the C-19 protons of 19-hydroxysterols and for the side chain protons of 30. Copyright (C) 1999 Elsevier Science Ireland Ltd.
Use of Polymeric Phosphine-Halogen Complexes in the Conversion of Epoxides to Halohydrins
Caputo, Romualdo,Ferreri, Carla,Noviello, Silvana,Palumbo, Giovanni
, p. 499 - 501 (2007/10/02)
Polystyryldiphenylphosphine-halogen complexes are convenient reagents for converting epoxides to halohydrins under mild and non-acidic conditions.The method requires only a filtration and evaporation process for product isolation.
Aliphatic Liquid Crystals, 6 - Cholesteric 19-Norcholesteryl Esters
Sucrow, Wolfgang,Howard, Susanne
, p. 4341 - 4346 (2007/10/02)
19-Norcholesterol (6a) was prepared on a known route and esterified with 14 aliphatic and 3 aromatic acids.The aliphatic esters 6c - p and the anisate 6r exhibit cholesteric phases broader than those of the corresponding cholesteryl esters.This effect is caused by a lowering of the melting points which is explained with a less stable packing of the crystal lattices.
