CALCOGÊNAÇÃO ONE POT DE 1,3,4-OXADIAZÓIS COM HALETOS ORGÂNICOS E Se/S ELEMENTAR CATALISADA POR NANOPARTÍCULAS DE CuO

Abstract

The search for sustainable methodologies in the synthesis of heterocyclic compounds is crucial for fields such as pharmacology, agrochemistry, and material science. Grounded in the principles of green chemistry, these approaches offer safe and efficient alternatives, reducing the environmental and energy impacts of traditional methods. Selenium, in turn, plays an essential role in biological systems, as seen in glutathione peroxidase (GPx), a selenoprotein that reduces oxidative stress and protects normal cells during treatments like chemotherapy and radiotherapy. However, tumor cells can exploit these proteins as a defense mechanism, impairing therapeutic efficacy. In this context, the chalcogenation of bioactive compounds, such as 1,3,4-oxadiazole derivatives, emerges as a promising alternative, as these compounds can act as bioisosteres of esters and amides, as well as peptidomimetics, enhancing their ability to mimic selenoproteins. In this study, 11 derivatives of 1,3,4-oxadiazoles were synthesized from commercial carboxylic acids, focusing on the chalcogenation of these compounds. The methodology employs copper (II) oxide nanoparticles as a catalyst, elemental selenium or sulfur, and organic halides under optimized conditions. This approach led to the production of 29 compounds, including 4 novel ones, with yields ranging from 49 to 97%. The structures of all compounds were confirmed using advanced spectroscopic techniques, including 1H, 13C, and 77Se NMR. The methodology stands out for its low catalytic load (2.5 mol%), execution in an open atmosphere, and reduced reaction times, demonstrating versatility and significant potential to contribute to green chemistry and the development of new bioactive compounds.