Synthesis and biological evaluation of novel 2-(substituted isoxazol-4-yl)-5-arylamino-1,3,4-oxadiazoles

A series of 2-(5-methyl-3-(4-chloro/trifluoromethylphenyl)isoxazol-4-yl)-5-arylamino-1,3,4-oxadiazoles were synthesized from 4-chloro/trifluoromethyl benzaldehyde, ethyl acetoacetate, hydroxylamine hydrochloride, hydrazine hydrate, and aryl isocyanate by multi-step reactions. The structures of the target compounds were elucidated by IR, 1 H NMR, MS, and elemental analysis. All these compounds were tested for in vitro antifungal activities against Botrytis cinerea and Rhizoctonia cerealis by the mycelium growth rate method, and the results indicated that some compounds displayed high antifungal activity against Botrytis cinerea.