Facile Heterocyclic Synthesis and Antibacterial Activity of Substituted Isoxazol-5(4H)-ones

An efficient, simple, and green procedure for the synthesis of isoxazol-5(4H)-one derivatives are described here through a convenient one-pot, three-component reaction at room temperature. The title compounds are isolated in high to excellent yields and after short reaction times, and are characterized by various spectroscopic methods such as IR, H-1 NMR, and C-13 NMR. The synthesized compounds 4a-c and 4e-i were tested for their in vitro activity against a panel of Gram-positive and Gram-negative bacteria, demonstrating their ability to inhibit microorganisms with a zone of inhibition ranging from 15 to 30 mm, minimum inhibitory concentration between 250 and 900 g/mL, and minimum bacterial concentration between 700 and 1000 g/mL.