FARIAS, L. G.; http://lattes.cnpq.br/3631667324048672; FARIAS, Lívia Gouveia de.
Abstract:
Research involving molecules containing heterocyclic rings has been increasing over recent
years, especially due to their stability, reactive sites, enhanced solubility, and applications in
medicinal, technological, and agrochemical chemistry. Among the various heterocyclic rings,
1,2,4-oxadiazoles stand out, a compound of natural origin that can be easily synthesized.
Additionally, the search for new drugs requires toxicological studies to verify the effect of these
substances on biological systems. Thus, the present study aimed to analyze the reaction
conditions for the synthesis and characterization of 1-(5-phenyl-1,2,4-oxadiazol-3-yl)-propan-
2-one, as well as to evaluate its toxicity against Artemia salina. Initially, benzamidoxime was
synthesized from the reaction between benzonitrile, hydroxylamine hydrochloride, and
potassium carbonate in a hydroalcoholic medium, yielding 82.7%. Subsequently, a domestic
microwave oven was calibrated, followed by the synthesis of 1-(5-phenyl-1,2,4-oxadiazol-3-
yl)-propan-2-one using benzamidoxime, potassium carbonate, ethyl acetoacetate, and
dimethylformamide under microwave irradiation at 80%, 90%, and 100% power, yielding the
desired compound at 71%, 64%, and 61% respectively. Benzamidoxime and 1-(5-phenyl-1,2,4-
oxadiazol-3-yl)-propan-2-one were characterized by infrared (IR) spectroscopy and proton and
carbon-13 nuclear magnetic resonance (H1 and C13 NMR) techniques, confirming their
structures. Finally, the toxicity of the studied oxadiazole and ethyl acetoacetate ester was
evaluated against Artemia salina larvae, with LC50 values of 56.4 μg/mL and 2028.64 μg/mL,
respectively, demonstrating the high toxicity of the oxadiazole and the weak toxicity potential
of the ester towards the tested organism. Therefore, based on the results obtained, it is concluded
that 80% power represented the best strategy for oxadiazole synthesis, and the toxicological
bioassay reinforced the need for new biological studies planned for the synthesized oxadiazole
to further analyze this pharmacophore group and potentially solve various health problems.
