Abstract:

23 novel L-carvone-derived oxime sulfonate compounds 3a-3w were synthesized through hydroxylamine hydrochloride oximation and o-sulfonylation reactions using L-carvone(1) as the starting material. The structures of the target compounds were characterized by ¹H NMR, ¹³C NMR, FT-IR and HRMS. The antifungal activities of the target compounds against 8 tested plant pathogens were evaluated by agar dilution method. The results showed that the target compounds exhibited certain antifungal activities against the tested plant pathogens at the mass concentration of 50 mg/L. Among them, compounds 3b(R=o-FPh), 3c(R=m-FPh) and 3h(R=p-ClPh) had inhibition rates against Physalospora piricola of 76.7%, 75.9%, and 78.3%(all in B-class activity level), which were better than that of the positive control chlorothalonil. Compound 3h displayed certain broad-spectrum antifungal activity owing to its good inhibition rates of 78.4%, 78.3%, 82.2%, and 78.8%, against Fusarium oxysporum f. sp. cucumerinum, Physalospora piricola, Bipolaris maydis, and Colleterichum orbicalare, respectively(all in B-class activity level). Compound 3b also displayed certain broad-spectrum antifungal activity owing to its good inhibition rates of 76.7%, 77.5%, and 78.6%, against P. piricola, B. maydis, and C. orbicalare, respectively(all in B-class activity level).

Key words: L-carvone, oxime sulfonate, antifungal activity, synthesis