Synthesis and nematicidal activity of 4,5,5-trifluoro-N-(heteroaryl methyl) pent-4-enamide

Plant parasitic nematodes may cause severe damages to crops globally. In this study, fifteen novel 4,5,5-trifluoropent-4-enamide derivatives were designed and synthesized, and their nematicidal activities both in vitro and in vivo (in sand) were determined. Compounds with high activity in sand were further investigated for their in vivo activities in matrix. Results of the in vitro test showed that some of compounds exhibited better nematicidal activity. Among the synthesized molecules, compounds   B8   containing a furan ring exhibited excellent nematicidal activity against Meloidogyne incognita and Bursaphelenchus xylophilus, with LC_{50/72 h} values of 1.22 mg/L and 0.53 mg/L, respectively. Furthermore, most of the compounds showed 100% inhibition rate against M. incognita at 40 mg/L in sand in the in vivo test. Among which compound   B10   containing a benzothiazole ring showed the best nematicidal activity. It exhibited 66.0% inhibition rate at 2.5 mg/L. Results of the in vivo test in matrix showed that compound   B6   containing a thiophene ring was the most active compound. It showed 31.0% inhibition rate at 5 mg/L. Preliminary analysis on structure-activity relationship showed that the compounds containing non-substituted five-membered ring such as thiophene, furan and thiazole demonstrated better bioactivity than those compounds containing bulky six-membered ring or fused ring in the molecule.