10505-00-7Relevant articles and documents
The Unexpected Role of SeVI Species in Epoxidations with Benzeneseleninic Acid and Hydrogen Peroxide
Back, Thomas G.,Gelfand, Benjamin S.,George, Graham N.,Mendoza Rengifo, Emerita,Pickering, Ingrid J.,Sands, Kai N.
, p. 4283 - 4287 (2020)
Benzeneperoxyseleninic acid has been proposed as the key intermediate in the widely used epoxidation of alkenes with benzeneseleninic acid and hydrogen peroxide. However, it reacts sluggishly with cyclooctene and instead rapidly decomposes in solution to
The polyhedral nature of selenium-catalysed reactions: Se(iv) species instead of Se(vi) species make the difference in the on water selenium-mediated oxidation of arylamines
Capperucci, Antonella,Dalia, Camilla,Tanini, Damiano
, p. 5680 - 5686 (2021/08/16)
Selenium-catalysed oxidations are highly sought after in organic synthesis and biology. Herein, we report our studies on the on water selenium mediated oxidation of anilines. In the presence of diphenyl diselenide or benzeneseleninic acid, anilines react with hydrogen peroxide, providing direct and selective access to nitroarenes. On the other hand, the use of selenium dioxide or sodium selenite leads to azoxyarenes. Careful mechanistic analysis and 77Se NMR studies revealed that only Se(iv) species, such as benzeneperoxyseleninic acid, are the active oxidants involved in the catalytic cycle operating in water and leading to nitroarenes. While other selenium-catalysed oxidations occurring in organic solvents have been recently demonstrated to proceed through Se(vi) key intermediates, the on water oxidation of anilines to nitroarenes does not. These findings shed new light on the multifaceted nature of organoselenium-catalysed transformations and open new directions to exploit selenium-based catalysis.
One-Pot Synthesis of Aryl Selenonic Acids and Some Unexpected Byproducts
Back, Thomas G.,Gelfand, Benjamin S.,Sands, Kai N.
, p. 9938 - 9944 (2021/07/31)
The synthesis of aryl selenonic acids was achieved from diverse aryl bromides via a one-pot method involving metalation, selenation, and oxidation with hydrogen peroxide followed by ion exchange to afford the pure products in 77-90% yield. An o-hydroxymethyl derivative was found to dehydrate readily, affording the first example of a cyclic selenonic ester, while two minor byproducts were isolated and shown by X-ray crystallography to be mixed salts of aryl selenonic acids with either the corresponding aryl seleninic or selenious acid.
Modelling the Inhibition of Selenoproteins by Small Molecules Using Cysteine and Selenocysteine Derivatives
Reddy, Kishorkumar M.,Mugesh, Govindasamy
, p. 8875 - 8883 (2019/06/17)
Small molecule-based electrophilic compounds such as 1-chloro-2,4-dinitrobenzene (CDNB) and 1-chloro-4-nitrobenzene (CNB) are currently being used as inhibitors of cysteine- and selenocysteine-containing proteins. CDNB has been used extensively to determine the activity of glutathione S-transferase and to deplete glutathione (GSH) in mammalian cells. Also, CDNB has been shown to irreversibly inhibit thioredoxin reductase (TrxR), a selenoenzyme that catalyses the reduction of thioredoxin (Trx). Mammalian TrxR has a C-terminal active site motif, Gly-Cys-Sec-Gly, and both the cysteine and selenocysteine residues could be the targets of the electrophilic reagents. In this paper we report on the stability of a series of cysteine and selenocysteine derivatives that can be considered as models for the selenoenzyme–inhibitor complexes. We show that these derivatives react with H2O2 to generate the corresponding selenoxides, which undergo spontaneous elimination to produce dehydroalanine. In contrast, the cysteine derivatives are stable towards such elimination reactions. We also demonstrate, for the first time, that the arylselenium species eliminated from the selenocysteine derivatives exhibit significant redox activity by catalysing the reduction of H2O2 in the presence of GSH (GPx (glutathione peroxidase)-like activity), which suggests that such redox modulatory activity of selenium compounds may have a significant effect on the cellular redox state during the inhibition of selenoproteins.
BENZENEPEROXYSELENINIC ACIDS - SYNTHESIS AND PROPERTIES
Syper, Ludwik,Mlochowski, Jacek
, p. 207 - 214 (2007/10/02)
Benzeneperoxyseleninic acid (3) and its analogs, 2-nitro and 2,4-dinitrobenzeneperoxyseleninic acids (10, 11), were obtained by oxidation of corresponding arylseleninic acids or diaryldiselenides with hydrogen peroxide.Their chemical properties were studied and rearrangement of 3 to benzeneselenic acid 7 was found as an useful method for preparation of this compound.It was also shown that peroxyseleninic acid 10 can be used as an efficient oxidant in the Baeyer-Villiger transformation of the formyl group into formyloxy one.
