Discovery of N‐benzyl‐6‐methylpicolinamide as a potential scaffold for bleaching herbicides

Abstract

AbstractBACKGROUNDIn pesticide research, bleaching herbicides have always been a hot topic. Our previous research showed that N‐(4‐fluorobenzyl)‐2‐methoxybenzamide is an innovative lead compound for bleaching herbicides.RESULTSA total of 40 derivatives of picolinamides were prepared and evaluated for their herbicidal activity by Petri dish tests and postemergence trials. The structure–activity relationship (SAR) revealed that introducing electron‐withdrawing groups at the 3‐ or 4‐positions of the benzyl significantly enhances herbicidal activity. Furthermore, ZI‐04 induced similar symptoms such as bleaching effect in treated weeds and accumulation of biosynthetic precursors for carotenoids as observed with diflufenican. ZI‐04 also exhibited significant cross‐resistance to diflufenican and had a lower resistance risk than diflufenican.CONCLUSIONN‐benzyl‐6‐methylpicolinamides were discovered as a novel scaffold for bleaching herbicides. The accumulation of phytoene, phytofluene and ζ‐Carotene in radish cotyledons, and cross‐resistance observed with diflufenican, showed that title compounds can interfere with carotenoid biosynthesis. © 2024 Society of Chemical Industry.