Design, Ultrasonic-assisted Synthesis and Evaluation In vitro Antimicrobial Activity of Bis-isoxazole Derivatives Bearing Chloro-pyridinyl Group

A n ultrasonic-assisted synthesis of bis-isoxazole derivatives was developed. Eight 3-(6-chloropyridin-3-yl)-5-{[(3-arylisoxazol-5-yl)methoxy]methyl}isoxazoles were synthesized by 1,3-dipolar cycloaddition reaction between substituted isoxazolyl alkyne compounds and 6-chloro- N -hydroxynicotinimidoyl chloride. The structures of the synthesized compounds were confirmed by HRMS, FTIR, 1 H and 13 C NMR spectroscopy. Wherein, the antifungal and antibacterial activities of target compounds were tested. The synthesized compounds 6 a and 6 h exhibited better antifungal activity in comparison with the standard drug itraconazole. The minimum inhibitory concentrations(MICs) of both compound 6 a and compound 6 h were both 4 µg/mL against Candida albicans ATCC 10231.