In the face of increasing resistance to the currently used commercial herbicides and the lack of success in identifying new herbicide targets, alternative herbicides need to be developed to control unwanted monocotyledon grasses in food crops. Here, a panel of 29 novel sulfonylurea-based compounds with ortho-fluoroalkoxy substitutions at the phenyl ring were designed and synthesized. Pot assays demonstrated that two of these compounds, 6d and 6u, have strong herbicidal activities against Echinochloa crus-galli, Eleusine indica, Alopecurus aequalis, and Alopecurus japonicus Steudel at a dosage of 15 g ha^–1. Furthermore, these two compounds exhibited <5% inhibition against wheat at a dosage of 30 g ha^–1 under post-emergence conditions. 6u also exhibited <5% inhibition against rice at a dosage of 30 g ha^–1 under both post-emergence and pre-emergence conditions. A kinetics study demonstrated that 6d and 6u are potent inhibitors of Arabidopsis thaliana acetohydroxyacid synthase (AHAS; EC 2.2.1.6) with potent K_i values of 18 ± 1.1 and 11.9 ± 4.0 nM, respectively. The crystal structure of 6u in complex with A. thaliana (At)AHAS has also been determined at 2.7 Å resolution. These new compounds represent new alternative herbicide choices to protect wheat or rice from invading grasses.

中文翻译：

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化学合成、除草活性、作物安全性和邻氟烷氧基取代磺脲类药物作为新型乙酰羟酸合酶抑制剂的分子基础


面对对目前使用的商业除草剂的抗药性越来越大，以及在确定新的除草剂靶点方面缺乏成功，需要开发替代除草剂来控制粮食作物中不需要的单子叶植物。在这里，设计并合成了一组在苯基环处具有邻氟烷氧基取代的新型磺酰脲类化合物。罐式试验表明，其中两种化合物 6d 和 6u 在 15 g ^ha-1 的剂量下对 Echinochloa crus-galli、Eleusine indica、Alopecurus aequalis 和 Alopecurus japonicus Steudel 具有很强的除草活性。此外，在出苗后条件下，这两种化合物在 30 g ha^–1 的剂量下对小麦表现出 <5% 的抑制作用。在出苗后和出苗前条件下，6u 在 30 g ha^–1 的剂量下对水稻也表现出 <5% 的抑制作用。动力学研究表明，6d 和 6u 是拟南芥乙酰羟基酸合酶 （AHAS;EC 2.2.1.6） 的有效 K_i 值分别为 18 ± 1.1 和 11.9 ± 4.0 nM。6u 与拟南芥 （At）AHAS 复合物的晶体结构也已在 2.7 Å 分辨率下确定。这些新化合物代表了保护小麦或水稻免受草类入侵的新替代除草剂选择。