3-苄基-5-(1-(2-氧代-1-氧杂螺[4,5]癸-3-烯-3-基)亚乙基)-2-氨基咪唑啉-4-酮类化合物的合成及杀菌活性

为寻找高活性的杀菌化合物，在前期合成5-(1-(4-甲基-2-氧代-1-氧杂螺[4,5]癸-3-烯-3-基) 亚乙基)-2-氨基咪唑啉-4-酮类化合物的基础上进行结构修饰，在咪唑啉-4-酮的3-位引入苄基，设计并合成了一系列未见文献报道的化合物，其结构经过核磁共振氢谱 (1H NMR)、碳谱 (13C NMR) 及高分辨质谱 (HR-ESI-MS) 确证。经高效液相色谱 (HPLC) 分析显示，Z-构型中间体化合物 6 在酸性条件下会发生氮质子化开环再环化，转化为E-构型化合物 7 。离体杀菌活性测定结果表明，3-位苄基的引入改善了该类化合物的杀菌活性，其中化合物 (E)-3-苄基-5-(1-(4-甲基-2-氧代-1-氧杂螺[4,5]癸-3-烯-3-基) 亚乙基)-2-(4-甲氧基苯基) 氨基-咪唑啉-4-酮 ( 9c ) 和 (E)-3-苄基-5-(1-(4-甲基-2-氧代-1-氧杂螺[4,5]癸-3-烯-3-基) 亚乙基)-2-(4-氟苯基) 氨基-咪唑啉-4-酮 ( 9h ) 对油菜菌核病菌的EC₅₀ 值分别为14.3和21.1 mg/L。活体杀菌活性测试结果显示，在400 mg/L下化合物 9c 对于黄瓜霜霉病和小麦白粉病的防治效果分别为 80%和85%。

Synthesis and fungicidal activity of 3-benzyl-5-(1-(2-oxo-1-oxaspiro[4,5]dec-3-en-3-yl)ethylidene)-2-aminoimidazolin-4-one derivatives

In order to discover novel compounds with high fungicidal activities, a series of novel compounds were designed and synthesized based on the structural modification of 5-(1-(4-methyl-2-oxo-1-oxaspiro[4,5]dec-3-en-3-yl)ethylidene)-2-aminoimidazolin-4-one derivatives, and introduction of a benzyl group at the 3-position of imidazolinone. Their structures were characterized by 1H NMR, 13C NMR and HR-ESI-MS spectral data. Furthermore, these results of HPLC analysis verified that the Z-configuration of compound 6 would be reversed to the E-configuration of 7 through nitrogen protonation, ring opening, and ring reclosing processes under acidic conditions. The preliminary in vitro evaluation results showed that the introduction of the 3-benzyl group significantly improved the fungicidal activity of this type of compounds, and the EC₅₀ value of 3-benzyl-5-(1-(4-methyl-2-oxo-1-oxaspiro[4,5]dec-3-en-3-yl)ethylidene)-2-(4-methoxy-phenylamino)-imidazolin-4-one ( 9c ) and 3-benzyl-5-(1-(4-methyl-2-oxo-1-oxaspiro[4,5]dec-3-en-3-yl) ethylidene)-2-(4-fluorophenylamino)-imidazolin-4-one ( 9h ) against Sclerotinia sclerotiorum were 14.3 and 21.1 mg/L, respectively. In the in vivo evaluation, the efficacies of compounds 9c were 80% and 85% against cucumber downy mildew and wheat powery mildew at a concentration of 400 mg/L, respectively.