Synthesis of Organic Selenides and Tellurides for Detection and Interception of Endogenous Oxidants

Abstract

Fluorescent probes that are able to detect entities involved with biological disorders may be applied for diagnostic or even therapeutic applications as for instance, intercepting such entities/metabolic way. An efficient way to identify specific pathologies - especially those related to oxidative processes - is through the detection of oxidant entities here coined as endogenous oxidant (OxEn - we will maintain the Portuguese abbreviation). A myriad of fluorescent probes based on the emission (on) and suppression (off) of fluorescence, modulated by Photoinduced Electron Transfer (PET), have been employed to detect these kinds of entities. When bounded to fluorophores, both selenium and tellurium atoms suppress the fluorsecence (off) of a given molecular scaffold, by the PET-process. When the Se or Te atoms are oxidized to higher oxidation levels, the fluorescent capacity of the nuclei is reestablished (on). This property, associated to the high oxidation potential of these chalcogen atoms in the II-oxidation state, confers to these fluorescent entities, the ability to detect OxEn. Additionally, although many have addressed the possible toxicity of these classes of compounds, there is no scientific basis that either denies or confirms this. On the contrary, selenium derivatives present several benefits and possess vital nutritional properties. Due to the afore mentioned properties, this project aims to prepare fluorescent seleno- and telluro-derivatives for specific cell labeling related to oxidative processes and analytical applications. As there are only a few restricted examples of these kinds of derivatives (Se- and Te- fluorophores) for the proposed applications, we will pay special attention to the synthesis of a diverse class of compounds aimed to better understand their fundamental properties and possible applications. Specifically, we will focus on the synthesis of seleno- and telluro-coumarines, -flouresceines, -rhodamines and indolizidines.The studies related to the interception of endogenous oxidant entities, related to inflammation process will be conduced in the group of professor Flavia C. Meotti of Department of Biochemistry of the IQ-USP. The part related to the application of the chalcogeno-fluorophores will be conduced in the group of professors Carlos L. Espiño and J. L. Capelo Martinez - both from Universidade Nova de Lisboa (Portugal) - with whom we have a productive cooperation program involving PhD students and a special Visitor Researcher project of CNPq through a Science Without Borders Program. (AU)