Synthesis And Fungicidal Activity Of Some3,5-disubstituted Isoxazoline Derivatives

Isoxazoline derivatives has attracted more and more attentions for its extensivebiological activity, This paper focus on the synthesis of a series of isoxazoline via1,3-dipolar cycloaddition reaction.In order to find new isoxazoline that has well biological activity, varioussubstituted aromatic aldehydes as raw material, followed by a three-step syntheticprocedure including addition-elimination, chlorination, and1,3-dipolar cycloadditionto generated isoxazolines. First, the substituted aromatic aldhydes reacted withhydroxylamine hydrochloride, form the substituted aromatic aldehyde oxime, then bythe chlorination with NCS, to form the corresponding chlorinated aromatic aldoximes,and then the chlorinated aromatic aldoximes under the effect of triethylamine,underwent the1,3-dipolar cycloaddition reaction with N-vinylpyrrolidone,2-vinylpyridine and4-vinylpyridine, respectively, to generate sixteen novelcompounds containing isoxazoline ring.All the3,5-disubstituted isoxazoline derivatives have been characterized by1HNMR,13C NMR, and HRMS. With the standard bioassay method-growth rate method,the target compounds were evaluated for their fungicidal activites against Fusariumoxysporium, Cercospora arachidicola, Physalospora piricola, Alternaria solani,Fusarium graminearum, Rhizoctoniasolani, Phytophthora capsici, Botrytis cinerea,Sclerotinia sclerotiorum and Rhizoctonia solani in vitro, and the broad spectrumantibacterial drug chlorothalonil as control drug. Preliminary biological activity testsin vitro indicated that the compound3c displayed excellent fungicidal activity againstB. cinerea. The compound3d displayed excellent fungicidal activity against A. solani,C. arachidicola and S. Sclerotiorum. The compounds3f-3p displayed excellentfungicidal activity against C. arachidicola, P. piricola, A. solani, F. graminearum, P.capsici, S. sclerotiorum, R. solani in the test concentrations.