Synthesis and Antifungal Activities of Novel Strobilurin Derivatives Containing Quinolin-2(1H)-one Moiety

To discover novel lead compounds with better antifungal activities, a series of novel strobilurin derivatives containing quinolin-2(1H)-one moiety was designed and synthesized via intermediate derivatization method. Their structures were characterized by means of ¹H nuclear magnetic resonance(¹H NMR), ¹³C NMR and high resolution mass spectrometry(HRMS). The biological assay results indicate that most target compounds exhibit good to excellent fungicidal activities against 10 plant pathogens. Compounds 4d, 5b and 5c possess 94.1%, 83.8% and 80.9% in vitro inhibition respectively against Rhizotonia cereals at the concentration of 50 μg/mL, which are better than that of the control agents. Especially, the inhibition activities of compound 4d against all of the tested fungi approach or exceed those of the controls. The structure-activity relationship was also discussed.