The reaction mechanism of the GPx-like oxidation of PhSH with H(2)O(2) catalyzed by selenoxides proceeds via formation of the hydroxy perhydroxy selenane, which is a stronger oxidizing agent than selenoxide. A hydroxy perhydroxy selenane intermediate was observed by electrospray ionization mass spectrometry and (77)Se NMR spectroscopy in reactions of selenoxide 8 with H(2)O(2).The initial velocity of oxidation of PhSH by H(2)O(2) with selenoxide 8 is 4 orders of magnitude higher than that of 8 without peroxide. Selenoxide 8 is not reduced to selenide 6 by PhSH in the presence of H(2)O(2). While electronic substituent effects have minimal impact on the catalytic performance of selenoxides, chelating groups increase the rate of catalysis.

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A glutationa peroxidase (GPx) é uma importante enzima que faz parte do sistema de defesa do organismo frente a substâncias nocivas formadas durante o metabolismo do oxigênio, como peróxidos e seus derivados. Diversas estratégias para desenvolver novos miméticos, assim como para aumentar a atividade mimética da GPx em compostos como disselenetos, selenetos e teluretos, vêm sendo propostas nos últimos anos. Nesta revisão é apresentado um balanço, dos últimos dez anos, referente ao desenvolvimento e à avaliação de catalisadores organoselênio ou organotelúrio capazes de mimetizar a atividade da GPx. Diferentes mecanismos de ação destes compostos também são apresentados, de acordo com os novos avanços desta relevante área de pesquisa.This review covers the past decade of intensive research on the design, synthesis and screening of organoselenides and tellurides as catalyst able to mimic the activity of the selenoenzyme glutathione peroxidase (GPx). This important enzyme forms part of the detoxification system in humans which deals with harmful peroxides and their byproducts formed during oxygen metabolism. Several strategies to enhance the GPx-like activity of compounds such as diselenides, selenides and tellurides have been proposed in recent years. Different mechanisms of action of these compounds are also presented in this review highlighting new advances in this exciting research field.

A series of modular telluroamino acid derivatives with remarkable GPx-like behavior was prepared in an efficient and short two-step synthesis.

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