Diaryl diselenides and benzisoselenazol-3(2H)-ones as oxygen-transfer agents

Młochowski, J.; Brzaszcz, M.; Chojnacka, M.; Giurg, Mirosław; Wójtowicz, Halina

doi:10.3998/ark.5550190.0005.319

Cited by 23 publications

References 37 publications

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Organoselenium and Organotellurium Oxidation and Reduction

Młochowski

Lisiak

Wójtowicz‐Młochowska

2011

Patai's Chemistry of Functional Groups

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Oxygenated and reduced selenium and tellurium compounds, particularly thoese of practical importance have been extensively investigated especially during the last few decades. Selenium(IV) oxide, selenoxides, selenones, seleninic and peroxyseleninic acids, selenenamides and seleninamides are involved in oxyfunctionalization of unsaturated hydrocarbons, their derivatives, alkylarenes, sulfides and amines, carbon‐oxygen and carbon‐carbon bond cleavage, ring closure and ring transformations, syn ‐elimination, sigmatropic [2,3]‐rearrangement and other, chemo‐ regio‐ and stereocontrolled reactions. The chemistry of oxygenated tellurium compounds has been less extensively explored than their selenium counterparts;, nevertheless some of them have been successfully used for oxyfunctionalization of different groups of organic compounds while telluroxide elimination has gained more attention in the last years becoming a well‐established method for the synthesis of olefins. Hydrogen selenide and telluride, alkali selenides and tellurides, selenoles and telluroles are the most common reduced derivative of these elements. Their properties are expressed in many reactions such as reduction and deoxygenation of different groups of organic compounds alkenes, alkynes, ethers, carbonyl compounds, esters, lactones, oxiranes, nitrogen, sulfur and halogen compounds, as well as dealkylation of tertiary amines. The method for preparation of the different oxygenated and reduced selenium and tellurium compounds are described, their reactions are reviewed, their usefulness in synthesis is indicated and more representative mechanisms are discussed.

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Organoselenium and Organotellurium Oxidation and Reduction

Młochowski

Lisiak

Wójtowicz‐Młochowska

2011

Patai's Chemistry of Functional Groups

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Synthesis and Antioxidant Activity of Peptide‐Based Ebselen Analogues

Satheeshkumar

Mugesh

2011

Chemistry A European J

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A series of di- and tripeptide-based ebselen analogues has been synthesized. The compounds were characterized by (1)H, (13)C, and (77)Se NMR spectroscopy and mass spectral techniques. The glutathione peroxidase (GPx)-like antioxidant activity has been studied by using H(2)O(2) , tert-butyl hydroperoxide (tBuOOH), and cumene hydroperoxide (Cum-OOH) as substrates, and glutathione (GSH) as a cosubstrate. Although all the peptide-based compounds have a selenazole ring similar to that of ebselen, the GPx activity of these compounds highly depends on the nature of the peptide moiety attached to the nitrogen atom of the selenazole ring. It was observed that the introduction of a phenylalanine (Phe) amino acid residue in the N-terminal reduces the activity in all three peroxide systems. On the other hand, the introduction of aliphatic amino acid residues such as valine (Val) significantly enhances the GPx activity of the ebselen analogues. The difference in the catalytic activity of dipeptide-based ebselen derivatives can be ascribed mainly to the change in the reactivity of these compounds toward GSH and peroxide. Although the presence of the Val-Ala-CO(2) Me moiety facilitates the formation of a catalytically active selenol species, the reaction of ebselen analogues that has a Phe-Ile-CO(2) Me residue with GSH does not generate the corresponding selenol. To understand the antioxidant activity of the peptide-based ebselen analogues in the absence of GSH, these compounds were studied for their ability to inhibit peroxynitrite (PN)-mediated nitration of bovine serum albumin (BSA) and oxidation of dihydrorhodamine 123. In contrast to the GPx activity, the PN-scavenging activity of the Phe-based peptide analogues was found to be comparable to that of the Val-based compounds. However, the introduction of an additional Phe residue to the ebselen analogue that had a Val-Ala dipeptide significantly reduced the potency of the parent compound in PN-mediated nitration.

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