Discovery of Novel Pyridazine Herbicides Targeting Phytoene Desaturase with Scaffold Hopping
Overview
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Phytoene desaturase (PDS) is a critical functional enzyme in blocking ζ-carotene biosynthesis and is one of the bleaching herbicide targets. At present, norflurazon () is the only commercial pyridazine herbicide targeting PDS. Therefore, developing new and diverse pyridazine herbicides targeting PDS is urgently required. In this study, diflufenican () was used as the lead compound, and a scaffold-hopping strategy was employed to design and synthesize some pyridazine derivatives based on the action mode of and PDS. The preemergence herbicidal activity tests revealed that compound 6-chloro--(2,4-difluorophenyl)-3-(3-(trifluoromethyl)phenoxy)pyridazine-4-carboxamide () with 2,4-diF substitution in the benzeneamino ring showed 100% inhibition rates against the roots and stems of and at 100 μg/mL, superior to the inhibition rates of . Meanwhile, compound demonstrated excellent postemergence herbicidal activity against broadleaf weeds, which was similar to that of (inhibition rate of 100%) but superior to that of . This indicated that 6-Cl in the pyridazine ring is the key group for postemergence herbicidal activity. In addition, compound could induce downregulation of PDS gene expression, 15--phytoene accumulation, and Y(II) deficiency and prevent photosynthesis. Therefore, can be considered as a promising candidate for developing high-efficiency PDS inhibitors.
Pyridazine and pyridazinone compounds in crops protection: a review.
Ma X, Sun P, Wang J, Huang X, Wu J Mol Divers. 2024; .
PMID: 39724455 DOI: 10.1007/s11030-024-11083-5.