Synthesis, characterization and preliminary antibacterial evaluation against Staphylococcus aureus of a new 2,4,5-tri(hetero)arylimidazole derivative based on azaindole heterocycle

Imidazole derivatives are known for their numerous biological applications, such as antibacterial, antifungal, antioxidant, antiviral, antiparasitic and anticancer, among others. Therefore, several imidazole derivatives have been synthesized and developed in recent years as potential drugs in the treatment of several diseases. In this communication, we report the synthesis of a new imidazole derivative, substituted at positions 2, 4 and 5 with heterocyclic groups, using a simple synthetic methodology and an easy purification procedure. The new compound was characterized by the usual spectroscopic techniques (NMR, UV-Vis absorption and emission). The evaluation of the novel imidazole derivative as a potential antibiotic drug was carried out against the Gram-positive bacterium Staphylococcus aureus, using disk test diffusion method. Results showed a dose-response effect against the bacteria under study, revealing that the rational design of this imidazole derivative is quite promising to improve antibacterial activity of imidazole derivatives.This research was funded by the Foundation for Science and Technology (FCT) through CQ/UM (UIDB/00686/2020) and “Contrato‐Programa” UIDB/04050/2020 funded by national funds. Thanks are also due to FCT for financial support to the Portuguese NMR Network (PTNMR, Bruker Avance III 400‐Univ. Minho)info:eu-repo/semantics/publishedVersio

Derivados de 2,4,5-tri(hetero)arilimidazoles: design, síntese e desenvolvimento para aplicações óticas e biológicas

Dissertação de mestrado em Técnicas de Caracterização e Análise QuímicaNovos derivados de 2,4,5-tri(hetero)arilimidazole 3a-b, 4a e 5b-c foram preparados por reação de aldeídos heterocíclicos e dionas (hetero)aromáticas apropriadas, por dois métodos diferentes. O primeiro envolvendo a síntese em ácido acético (3a-b e 4a) e o outro utilizando etanol como solvente e iodo como catalisador (4a, 5b-c). As propriedades fotofísicas destes novos imidazoles foram avaliadas pelas espetroscopias de absorção no UV-Vis e de fluorescência, em acetonitrilo. Os compostos foram avaliados como novos sensores químicos fluorimétricos para iões através de titulações espectrofluorimétricas com aniões e catiões biologicamente e analiticamente importantes, tais como fluoreto, cianeto, Hg(II), Ni(II) e Cu(II). Por fim, os derivados de imidazole foram avaliados quanto à sua atividade antibacteriana contra Staphylococcus aureus, por meio de dois métodos diferentes: teste de difusão em disco e de diluição em meio líquido. Os resultados revelaram que os imidazoles 3b, 4a e 5c-b apresentaram inibição do crescimento de S. aureus, sendo que o derivado 4a mostrou ter atividade antibacteriana superior comparativamente à ampicilina, usada como antibiótico de referência.Novel 2,4,5-tri(hetero)arylimidazole derivatives 3a-b, 4a and 5b-c were prepared by reaction of heterocyclic aldehydes and appropriate (hetero)aromatic diones, by two different methods. The first one involving the synthesis in acetic acid (3a-b and 4a) and the other one using ethanol as solvent and iodine as catalyst (4a, 5b-c). The photophysical properties of these new imidazoles were evaluated by UV-Vis absorption and fluorescence spectroscopies, in acetonitrile. The compounds were evaluated as novel fluorimetric chemosensors for ions through spectrofluorimetric titrations with biologically and analytically important anions and cations such as fluoride, cyanide, Hg(II), Ni(II) and Cu(II). Finally, imidazole derivatives were evaluated for their antibacterial activity against Staphylococcus aureus, by two different methodologies: disk test diffusion and broth dilution. Results revealed that imidazoles 3b, 4a and 5c-b showed inhibition of growth of S. aureus, and derivative 4a exhibit higher activity than ampicillin, used as standard antibiotic