2469-23-0Relevant articles and documents
Optimised conditions for the synthesis of 17O and 18O labelled cholesterol
De La Calle Arregui, Celia,Purdie, Jonathan A.,Haslam, Catherine A.,Law, Robert V.,Sanderson, John M.
, p. 58 - 62 (2016)
Conditions are described for the preparation of cholesterol with 17O and 18O labels from i-cholesteryl methyl ether using minimal amounts of isotopically enriched water. Optimum yields employed trifluoromethanesulfonic acid as catalyst in 1,4-dioxane at room temperature with 5 equivalents of water. An isotopic enrichment >90% of that of the water used for the reaction could be attained. Tetrafluoroboric acid could also be used as catalyst, at the expense of a lower overall reaction yield. Byproducts from the reaction included dicholesteryl ether, methyl cholesteryl ether, compounds formed by ether hydrolysis, and olefins arising from elimination reactions. Reactions in tetrahydrofuran yielded significant amounts of cholesteryl ethers formed by reaction with alcohols arising from hydrolysis of the solvent.
Dehydrative glycosylation with the Hendrickson reagent
Mossotti, Matteo,Panza, Luigi
scheme or table, p. 9122 - 9126 (2011/12/16)
The Hendrickson reagent is able to perform efficiently dehydrative glycosylation of 1-hydroxyglycosyl donors. The reaction occurs under mild conditions through an anomeric oxophosphonium intermediate detected by nuclear magnetic resonance. Further insight into the mechanism was gained by 18O labeling of anomeric OH.
Unusual electrochemical oxidation of cholesterol
Kowalski, Jan,Lotowski, Zenon,Morzycki, Jacek W.,Ploszynska, Jolanta,Sobkowiak, Andrzej,Wilczewska, Agnieszka Z.
, p. 543 - 548 (2008/09/17)
It has been found that cholesterol undergoes direct electrochemical oxidation on platinum electrode in dichloromethane. Voltammetric measurements show that the process is controlled by the rate of electron transfer and the height of the oxidation peak is linear vs. concentration of cholesterol. Preparative electrolysis with separated cathodic and anodic compartments afforded dicholesteryl ether in a relatively high material yield. Depending on electrolysis conditions (composition of supporting electrolyte and electrolytic cell construction) various by-products with a 3β-chloro, 3β-acetoxy, or 3β-acetylamino group were obtained.
