Síntese e avaliação da atividade antioxidante de calcogenilazidas e calcogeniltriazóis

Abstract

In this work, we developed a synthetic route for obtaining β-aryl-chalcogenoazide and β-aryl-chalcogenotriazole (S, Se and Te) derived from L-amino acids (L-phenylalanine, L-valine and L-leucine). We obtained a compounds library due to the structural diversity of amino acids, organochalcogen compounds and terminal alkynes used in this synthesis. For the synthesis of chalcogenides, L-amino acids have been submitted to reduction, protection and mesylation processes for obtain protected aminomesylate. With this requerid mesylate in hand, we turned our attention to the introduction of the organochalcogenide moiety in the mesylate through the nucleophilic substitution reaction of the OMs leaving group, obtaining compound. Subsequently, the β-chiral amines were prepared after removal of the Boc protecting group with trifluoracetic acid. Further, with the chiral β-chalcogenoamines in hand, we moved our attention to the synthesis of β-aryl-chalcogenoazide via diazotransfer reaction with triflyl azide (TfN3) as a diazo donor group. This procedure has several advantages such as high yield, complete retention of configuration, mild reaction conditions, and good compatibility with most functional groups. Firstly we carry out the synthesis of TfN3 with sodium azide, triflic anhydride and acetonitrile as solvent. After, it was added to the chiral β-chalcogen amines solution for subsequent diazotransfer reaction getting β-chalcogenazides. In view of the possibility of the synthesis of triazoles due to the presence of azido group, we decided to synthesize 1,2,3-triazoles. For this synthesis we used copper (II) as a catalyst and the product is only the regioisomer 1,4-substituted 1,2,3-triazole. The β-aryl-chalcogenoazide and β-aryl-chalcogenotriazole were submited to analysis of antioxidant properties by in vitro tests. The cyclic voltammetry technique was used to study the redox potential of the synthesized compounds.