To search for novel pesticides, the synthesis around commercialized insecticide tebufenpyrad accidentally led us to the discovery of the fungicidal lead compound, 3-ethyl-1-methyl-N-((2-phenylthiazol-4-yl)methyl)-1H-pyrazole-5-carboxamide (1a) and its pyrimidin-4-amine-based optimization derivative 5-chloro-2,6-dimethyl-N-(1-(2-(p-tolyl)thiazol-4-yl)ethyl)pyrimidin-4-amine (2a). Compound 2a not only demonstrates fungicidal activity superior to commercial fungicides such as diflumetorim but also exhibits the good features that come with pyrimidin-4-amines, such as unique modes of action and no cross-resistance to other pesticide classes. However, 2a is highly toxic to rats. Further optimization of 2a by introducing pyridin-2-yloxy substructure finally led to the discovery of 5b5-6 (HNPC-A9229) (5-chloro-N-(1-((3-chloropyridin-2-yl)oxy)propan-2-yl)-6-(difluoromethyl)pyrimidin-4-amine). HNPC-A9229 exhibits excellent fungicidal activities with EC₅₀ values of 0.16 mg/L against Puccinia sorghi and 1.14 mg/L against Erysiphe graminis, respectively. Not only that its fungicidal potency is significantly superior to or comparable to commercial fungicides including diflumetorim, tebuconazole, flusilazole, and isopyrazam, HNPC-A9229 possesses low toxicity to rats.

中文翻译：

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HNPC-A9229 的发现：一种新型 Pyridin-2-yloxy-Based Pyrimidin-4-amine 杀菌剂

为了寻找新型杀虫剂，围绕商品化杀虫剂 tebufenpyrad 的合成意外使我们发现了杀真菌先导化合物 3-ethyl-1-methyl- N -((2-phenylthiazol-4-yl)methyl)-1 H - pyrazole-5-carboxamide ( 1a ) 及其基于 pyrimidin-4-amine 的优化衍生物 5-chloro-2,6-dimethyl- N -(1-(2-(p-tolyl)thiazol-4-yl)ethyl)嘧啶-4-胺 ( 2a )。化合物2a不仅表现出优于商业杀真菌剂（如双氟嘧啶）的杀真菌活性，而且还表现出嘧啶-4-胺所具有的良好特性，例如独特的作用模式和与其他农药类别无交叉抗性。然而，2a对老鼠有剧毒。通过引入吡啶-2-基氧基子结构进一步优化2a，最终发现了5b5-6 ( HNPC - A9229 ) (5-chloro- N- (1 - ((3-chloropyridin-2-yl)oxy)propan- 2-基)-6-(二氟甲基)嘧啶-4-胺)。HNPC - A9229表现出优异的杀菌活性，EC _50值对高粱锈菌为 0.16 mg/L ，对白粉菌为 1.14 mg/L， 分别。HNPC-A9229 不仅杀真菌效力显着优于或相当于市售杀菌剂，包括双氟嘧啶、戊唑醇、氟硅唑和异吡唑啉酮，而且HNPC - A9229对大鼠的毒性较低。