Síntese de bistriazóis carbonilados simétricos via reação CuAAC: caracterização e estudos da reatividade, avaliação de suas propriedades biológicas e potencial uso como ligantes metálicos na determinação eletroquímica de metais: estudos sobre metodologias de abatimento do teor de cobre residual.

Abstract

Click chemistry represents an important strategy within studies in Organic Synthesis. Through its principles, based on Green Chemistry, we develop thermodynamically favorable methodologies, modular and stereospecific reactions, and the formation of stable products. One of the main reactions belonging to this class, and object of study of this work, is the CuAAC reaction - cycloaddition reaction between azide-alkyne catalyzed by copper (I). Through this reaction, it was possible to optimize the experimental parameters, which allowed the synthesis of 16 1,4-disubstituted symmetric carbonylated bistriazoles, with yields ranging from 48 to 97%, 15 of which have not yet been described in the literature, with their structures confirmed by spectroscopic and spectrometric techniques. In these preparations, it was possible to identify the presence of residual copper, at levels of up to ~60,000 ppm, complexed to the synthesized bistriazoles. For this reason, a proposal for an analytical methodology for metal abatement was developed, based on successive extractions with saturated EDTA solution, and sample preparation via digester block and quantification by FAAS, verifying an abatement of up to 97% of the residual copper content (final content ~1800 ppm). In addition to the synthetic aspects, their reactivity and stability were investigated, allowing the obtaining of new derivatives and expansion of proposals for functionalization and versatility of these structures. Complementarily, the new bistriazoles were tested for their fungicidal and antiTrypanosoma cruzi activities. The best result for antifungal activity, against Candida krusei ATCC 20298, was obtained by bistriazole with phenyl substituent, which presented the same MIC as fluconazole® (32 μg.mL-1). In the antiTrypanosoma cruzi evaluation, the tested compounds showed little activity and low levels of selectivity against amastigotes and trypomastigotes of the Tulahuen strain of T. cruzi. Finally, depending on the structural characteristics and substituent chains, five of the new bistriazoles were tested for their capacity as a metallic ligand in the preparation of selective electrodes. Bistriazoles were employed, applying electro-analytical techniques, in the identification of Pb2+, Cd2+, Fe2+ and Cr6+, with results of up to 600% optimization in detection, with detection limits between 10 – 100 µ.mol-1, when compared to standard carbon paste electrode.