Synthesis and antifungal activity of novel pyrazolines and isoxazolines derived from cuminaldehyde

Two series of novel cuminaldehyde derivatives containing pyrazoline and isoxazoline moieties have been designed and synthesized. All of the compounds were characterized via ¹H-NMR,¹³C-NMR, and HRMS. The antifungal activities were evaluated against six plant-pathogenic fungi. 3-(2-Fluorophenyl)-5-(4-isopropylphenyl) isoxazoline (2d) and 1-acetyl-3-(2-fluorophenyl)-5-(4-isopropylphenyl)-2-pyrazoline (3d) displayed higher antifungal activities than commercial fungicides against Sclerotinia sclerotiorum, Physalospora piricola and Pyricularia oryzae. The title compounds (2d and 3d) with strong antifungal activities are worth being further evaluated in vivo and in the field.