Green Multicomponent Synthesis, Antimicrobial and Antioxidant Evaluation of Novel 5-Amino-isoxazole-4-carbonitriles

Isoxazoles are five-membered aromatic heterocycles containing adjacent oxygen and nitrogen atoms. The Isoxazole ring system is found in variety of naturally occurringcompounds and biologically active molecules. They are especially useful in medicine, since many antifungal drugs belong to the isoxazole class [1]. Various methods weredeveloped for synthesizing isoxazole derivatives [2,3]. In this study, 5-aminoisoxazole- 4-carbonitriles were prepared via a green and efficient multicomponent procedure. Malononitrile, hydroxylamine hydrochloride and different aryl aldehydes were simultaneously reacted in K2CO3/glycerol deep eutectic solvent (1:4) (Fig. 1). Polysubstituted isixazoles were obtained in excellent yields and short times. Chemical structure of all molecules were characterized by spectral data and elemental analyses. In vitro inhibitory activity of all derivatives was evaluated against some pathogenic bacteria including both Gram-negative and Gram-positive strains as well as some fungi. Broad-spectrum antimicrobial activities were observed with isoxazoles. In addition, assessment of free radical scavenging activity of all the synthesized heterocycles against DPPH proved their antioxidant potentials