Síntesis y evaluación “in vitro” de la actividad antifúngica de oximas, éteres de oxima e isoxazoles

Abstract

Synthesis and in vitro assessment of antifungal activity of oximes, oxime ethers and isoxazoles. Objective. To synthesize and carryout a preliminary evaluation of the in vitro antifungal activity of oximes, oxime ethers and isoxazoles. Materials and methods. Oximeswere synthesized from aldehydes or ketones with NH2OH.HCl and K2CO3. Oxime ethers were prepared by alkylation of oximes withpropargyl bromide or 2-bromobenzyl bromide, using NaOH as base and acetone as solvent. The isoxazoles were obtained by 1,3-dipolarcycloadditions using ceric ammonium nitrate (CAN), chloramine T (CAT) and NaOCl. Products were identified or characterized usingnuclear magnetic resonance (NMR) and mass spectrometry (MS). Radial growth inhibition assays against Aspergillus niger and Fusariumroseum were carried out. Results. Five oximes, seven oxime ethers, four of them new, and four new isoxazoles were obtained. Theassessed substances exhibited antifungal activity in amounts of 1,5 mg and 3,0 mg. Conclusions. Although 1,3-dipolar cycloadditionsallowed to obtain the desired isoxazoles, this methodology produced a wide variety of side products that reduced yields and made difficultthe purification of the target products. Four of the tested compounds showed inhibition percentages greater than 80%.

Keywords

• oximes
• oxime ethers
• isoxazoles
• antifungal activity