α-(Substituted-phenoxyacetoxy)-α-heterocyclylmethylphosphonates: Synthesis, Herbicidal Activity, Inhibition on Pyruvate Dehydrogenase Complex (PDHc), and Application as Postemergent Herbicide against Broadleaf Weeds

Abstract

Pyruvate dehydrogenase complex (PDHc) is the site of action of a new class of herbicides. On the basis of the previous work for O,O'-dimethyl α-(substituted-phenoxyacetoxy)alkylphosphonates (I), further synthetic modifications were made by introducing a fural and a thienyl group to structure I. A series of α-(substituted-phenoxyacetoxy)-α-heterocyclylmethylphosphonate derivatives (II) were synthesized as potential inhibitors of PDHc. The postemergent activity of the title compounds II was evaluated in greenhouse experiments. The in vitro efficacy of II against PDHc was also examined. Compounds II with fural as R(3) and 2,4-dichloro as X and Y showed significant herbicidal activity and effective inhibition against PDHc from plants. O,O'-Dimethyl α-(2,4-dichlorophenoxyacetoxy)-α-(furan-2-yl)methylphosphonate II-17 had higher inhibitory potency against PDHc from Pisum sativum than against PDHc from Oryza sativa in vitro and was most effective against broadleaf weeds at 50 and 300 ai g/ha. II-17 was safe for maize and rice even at the dose of 900-1200 ai g/ha. Field trials at different regions in China showed that II-17 (HWS) could control a broad spectrum of broad-leaved and sedge weeds at the rate of 225-375 ai g/ha for postemergent applications in maize fields. II-17 (HWS) displayed potential utility as a selective herbicide.

Synthesis and Biological Applications of Phosphinates and Derivatives

“…These results underlined the beneficial effect produced by the trifluoromethyl group in this strategic position for enhancement of herbicidal activity [241]. Nevertheless, unlike phosphonate series 311 [242] and phosphonic acid monosodium salts series 312 [243], no inhibitory activity in vitro against PDHc from plants has been reported to confirm that PDHc was the biological target (Fig. 36).…”

Synthesis, crystal structure, herbicidal activities and 3D-QSAR study of some novel 1,2,4-triazolo[4,3-a ]pyridine derivatives

“…The herbicidal activities of compounds 2a to 2y against monocotyledon weeds such as Echinochloa crusgalli , Digitaria sanguinalis and Setaria faberii and dicotyldon weeds such as Amaranthus retroflexus , Eclipta prostrata and Brassica juncea were evaluated according to the reported procedure . 2,4‐D and penoxsulam were selected as positive controls.…”

Synthesis and herbicidal activity of aryloxyacetic acid derivatives as HPPD inhibitors

“…The commercially available starting materials reacted with methyl chloroacetate in CH3CN and anhydrous potassium carbonate (K2CO3) as the base, and the corresponding products C and K were prepared. The products were hydrolyzed using K2CO3 as a base to yield the product D and L [17][18][19][20][21]. In the presence of 3-(ethyliminomethylideneamino)-N, N-dimethyl propane-1-amine, hydrochloride (EDCI), the aromatic oxyacetic acid reacted with substituted 1,3-cyclohexanediones or substituted 1,3-dimethyl-1Hpyrazole-5-ol, using DMAP as the catalyst.…”