Synthesis of 3-furanyl-4,5-dihydroisoxazole Derivatives via Cycloaddition and their Antibacterial Evaluation

Background: Antimicrobial resistance is a major threat to human health. So this manuscript describes the synthesis of five different 3,5-disubstituted 4,5-dihydroisoxazoles with antimicrobial activity. Methods: They were obtained from nitrile oxide cycloaddition derived from 2-furaldehyde and 5- nitro-2-furaldehyde to different dipolarophiles (acrylamide, ethyl acrylate and styrene). All heterocycles were isolated (30-50 %) and characterized by FTIR, MS, 1H and 13C NMR, as they were also evaluated against Gram-positive and Gram-negative bacteria. Results and Conclusion: All products showed bioactivity against all bacteria, however, the heterocycle 3-(5-nitro-2-furanyl)-5-carboxylamide-4,5-dihydroisoxazole (6b) presented the lowest value for the minimum inhibition concentration (MIC - 14 μg/mL).