Phytoene desaturase (PDS), which catalyzes dehydrogenation of phytoene to zetacarotene, is the major target enzyme of herbicides in the carotenoid biosynthesis pathway. Up to now, the exact three-dimensional model of the herbicide binding region has not been reported. The two-dimensional and three-dimensional quantitative structure-activity relationship of the very active 3-trifluoromethyl-1,1'-biphenyl derivatives inhibiting phytoene desaturase were studied using Hansh-Fujita equation and CoMFA. By analyzing 2D and 3D results, we developed an approach to design new PDS inhibitors. So, novel pyrazole, pyridazine and oxadiazole derivatives were designed. 20 series totalling more than 200 compounds of pyrazole, pyridazine, oxadiazole derivatives were synthesized. All of the compounds were screened for herbicidal activity, most of these possessed bleaching activity and some compounds showed highly herbicidal activity in the greenhouse. Some of the title compounds exhibited excellent herbicidal activities against dicotyledonous plants B. campestris and A. retroflexus in post-emergence treatments at a rate of 7.5 gha-1.

Design and synthesis of novel bleaching herbicides

248th National Meeting (2014)

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