Synthesis, characterization, and antimicrobial evaluation of novel 1,2,4-oxadiazoles derived from trans-3,4-(methylenedioxy)-cinnamic acid

• Autor(a) principal: de Freitas Filho, João Rufino
• Data de Publicação: 2022
• Outros Autores: Ramos, Clécio Souza, Barros Bezerra, Leonardo Alexandre, Fonte Silva, Marcílio Wagner, Bezerra, Giselle Barbosa, de Freitas, Jucleiton José Rufino, Barbosa Freitas, Queila Patrícia da Silva
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Acta Brasiliensis (Online)
• Texto Completo: http://revistas.ufcg.edu.br/ActaBra/index.php/actabra/article/view/555

Compounds containing heterocyclic ring systems are of great importance both medicinally and industrially. Five-membered 1,2,4-oxadiazole heterocycles have received considerable attention because of their unique bioisosteric properties and unusual wide spectrum of biological activities. In this study, a series of 2-(3-aryl-1,2,4-oxadiazol-5-yl)-trans-3,4-(methylenedioxy)-cinnamyl derivatives was synthesized and characterized, and in vitro experimental models were used to evaluate their antimicrobial activity. Synthesis, which involved microwave irradiation for 5 min, provided moderate yields of 1,2,4-oxadiazole (34–50%). Infrared (IR) and nuclear magnetic resonance (1H NMR  and 13C NMR) spectroscopy were used to determine the structures of 1,2,4-oxadiazole. The disk diffusion method was used to test the antibacterial activity of the novel 1,2,4-oxadiazole derivatives against Gram-positive (Staphylococcus aureus, Enterococcus faecalis, and Bacillus subtilis) and Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacteria. The derivatives, 2-(3-m-toluyl-1,2,4-oxadiazol-5-yl)-3,4-(methylenedioxy)-cinnamyl and 2-(3-pyrimidyl-1,2,4-oxadiazol-5-yl)-3,4-(methylenedioxy)-cinnamyl exhibited a minimum inhibitory concentration (MIC) of 19.5 μg mL−1 against S. aureus, and is four-fold more potent than the standard metronidazole (MIC =78 μg mL−1).