18707-14-7Relevant academic research and scientific papers
Nitrogen Arylation for Macrocyclization of Unprotected Peptides
Lautrette, Guillaume,Touti, Fay?al,Lee, Hong Geun,Dai, Peng,Pentelute, Bradley L.
supporting information, p. 8340 - 8343 (2016/07/26)
We describe an efficient and mild method for the synthesis of macrocyclic peptides via nitrogen arylation from unprotected precursors. Various electrophiles and lysine-based nucleophiles were investigated and showed high-yielding product formation, even f
Chromium(VI) oxide catalyzed oxidation of sulfides to sulfones with periodic acid
Xu, Liang,Cheng, Jie,Trudell, Mark L.
, p. 5388 - 5391 (2007/10/03)
A highly efficient and selective oxidation of sulfides to sulfones with periodic acid catalyzed by CrO3 is described. A variety of electron-rich and electron-deficient sulfides were oxidized to sulfones with 2 mol% CrO3 in acetonitrile at room temperature in excellent yields. Sulfides with other readily oxidized functional groups were selectively oxidized to sulfones in high yields with 10 mol% CrO3 in ethyl acetate/acetonitrile at -35 °C.
Oxidation of Sulfur-Containing Compounds with HOF-CH3CN
Rozen, Shlomo,Bareket, Yifat
, p. 1457 - 1462 (2007/10/03)
The HOF-CH3CN complex, easily prepared by passing F2 through aqueous acetonitrile, is an exceptionally efficient oxygen transfer agent. All types of sulfides have been oxidized to sulfones in excellent yields, in a few minutes at room temperature. The reaction proceeds through the formation of sulfoxides which at low temperatures of around -75°C could be isolated in good yields. It was demonstrated through a reaction with thianthrene 5-oxide (20) that HOF·CH3CN is strongly electrophilic in nature. Sulfides with an electron-depleted sulfur atom such as perfluoroalkyl or aryl sulfides, which could not be well oxidized by any other method, were also efficiently converted to the corresponding sulfones in minutes. Thiophenes are generally hard to oxidize to the corresponding S-dioxides since the conditions required by the orthodox oxidants encourage consecutive typical ene and diene reactions. HOF·CH3CN requires short reaction times and low temperatures, thus enabling the isolation of thiophene dioxides, some of which could not be made by any other way. It seems that apart from unprotected amines, other functional groups such as aromatic rings, ketones, hydroxyls, and ethers do not interfere, since the sulfur atom reacts considerably faster.
Perfluoro- and Polyfluoro-sulphonic Acids. Part 22. Polyfluorophenyl Pentafluorobenzenesulphonates and their Electron Transfer Reaction with Sodium Iodide
Chen, Qing-Yun,Chen, Ming-Fang
, p. 1071 - 1075 (2007/10/02)
Polyfluorophenyl pentafluorobenzenesulphonates (1) have been synthesized in excellent yields by the reaction of pentafluorobenzenesulphonyl chloride with polyfluorophenoxides.Nucleophilic attack on 1 resulted in the breakage of the S-O bond accompanied by displacement of o- and /or p-fluorine.Reaction of 1 with sodium iodide (8) in a mole ratio of 1:3 (1:8) yielded polyfluorodiphenyl ethers 9 and 10 as the main products.However, p-C6F5OC6F4SO3C6F5 (12) was isolated as the major product in addition to 9 and 10 when the reactant ratio was 1:1 or 1:0.25.Reaction of 12 with sodium iodide also gave 9 and 10 when the reactant ratio was 1:3 (12:8).The reaction of 1 (or 12) with NaI is supposed to be an electron-transfer process.
Trimethylsilylesters of Fluorobenzenesulfonic acids
Johannsen, Heiner,Sartori, Peter
, p. 674 - 679 (2007/10/02)
Fluorobenzenesulfonic acids were prepared by electrophilic sulfonation of fluorobenzenes 1.The acids are obtained as hydrates and converted to their trimethylsilyl esters 2 for characterization.
