【作者】 李元祥；

【导师】 杨光富；

【作者基本信息】 华中师范大学 ， 农药学， 2007， 博士

【摘要】 嘧啶水杨酸类除草剂具有高效、安全、环境友好的特点，作用靶标为乙酰羟酸合成酶(Acctohydroxyacid Synthase)。其独特的作用机制在动植物之间有良好选择性，具有十分广阔的发展前景。自上世纪90年代以来，此类化合物的研究与开发取得了很大成就，成功地开发出嘧硫草醚(Pyrithiobac-sodium，KIH-2031)，嘧草醚(Pyriminobac-methyl，KIH-6127)、双草醚(Bispyribac-sodium，KIH-2023)、嘧啶肟草醚(Pyribcnzoxim，LGC-40863)和环酯草醚(Pyriftalid，CGA-279233)等除草剂新品种。由于长期施用，该类除草剂也产生了抗性。因此针对抗性的产生，要求不断改造更新除草剂品种的骨架结构。为了寻求高活性的结构骨架或先导结构，本文以现有商品化品种嘧草醚(Pyriminobac-methyl)、专利报道的活性化合物ZJ0777以及N-(2-(4，6-二甲氧基嘧啶-2-基)(羟甲基苯基))-1，1，1-三氟甲磺酰胺等具有高除草活性的品种为先导，针对它们物理特性或生物活性等方面的某些缺陷，采用生物等排原理与活性亚结构拼接方法设计合成了七类共153个4，6-二甲氧基嘧啶类化合物，除其中5个为已知物外，其余均是未见文献报道的新化合物，所合成的化合物都经过~1HNMR、MS以及元素分析等手段进行了结构表征，同时还采用X—射线衍射技术测定了8个代表性化合物的晶体结构。七类化合物的骨架结构如下：以稗草(Echinochloa crasgalli)、马唐(Digiatra sanguinalis)、狗尾草(Setaria viridis)、早熟禾(Annual bluegrass)、芥菜(Brassica juncea)、反枝苋(Amaranthus retroflexus)及小藜(Chenopodium album)等杂草为试验靶标，在用量为150 g／hm~2条件下，对所合成的化合物进行了芽后处理的盆栽普筛试验。试验结果显示，Ⅳ和Ⅴ两种结构类型化合物中，许多化合物都表现出良好的除草活性，比如Y6775、Y6776、Y6778、Y6795、Y67CN2和Y67CN7都表现出高效(防效在80％以上)和广谱的特征。进一步的初筛试验结果显示，Y6795在37.5 g／hm~2的低用量下对狗尾草(Setaria viridis)、小藜(Chenopodium album)、反枝苋(Amaranthus retroflexus)等杂草的防效也在80％以上。同时作物安全性评价结果显示了Y6795对油菜安全，其在油菜田的选择性试验有待进一步开展。化合物Y67CN2与Y67CN7的作物安全性评试验正在进行中。骨架Ⅰ和Ⅱ结构类型的化合物对杂草的防除活性较低或没有表现出除草活性，其骨架结构有待于进一步改造和修饰。骨架Ⅲ、Ⅵ和Ⅶ类型化合物的除草活性试验正在进行中。另外，我们还测试了合成得到的Ⅳ系列化合物对拟南芥AHAS的抑制活性，结果表明许多化合物在较低浓度下表现出良好的酶抑制活性，对杂草的伤害征兆(卷曲、灼伤和坏死等)为典型的AHAS抑制剂的症状。更多还原

【Abstract】 As a kind of inhibitors of Acetolactate Synthase, Pyrimidylsalicylate is highly effective, safe herbicide which also easily well going with environment. This kind of herbicides has a very bright future because of its unique action mechanism which did a great contribution to the high selectivity between animals and plants. Since the 90s of the last century, the research and exploration of this kind of compounds achieved great success. A series of commercial herbicides were found or explored, such as bispyribac-sodium (KIH-2023), pyribenzoxim (LGC-40863) and Pyriftalid (CGA-279233), etc. However, as we all know that the resistance appeared after the long term use of herbicides, new frame construction are needed to be found to keep or improve the biological activity.To investigate the highly effective frame construction or initial structure, based on the structures of the commercial herbicides such as Pyriminobac-methyl, patent compound ZJ0777 and N-(2-((4,6Klimemoxypyrimidin-2-yl)(hydroxy)methyl)phenyl)-1,1,1-trifluoromethanesulfonamide, 148 novel pyrimidine derivatives and 5 known compounds of seven series were designed and synthesized with the theory of bioisosteric replacement and the principle combination of active groups, which improved the disadvantages of physics and bioactivity. ~1H NMR, MS, spectrum, elemental analysis, X-ray diffraction analysis, and other related tools were used to characterize the structure of all synthesized compounds. The structures of the seven series compounds are shown as follows:Bioactivities of all compounds in postemergence treatments were performed at the concentration of 150 g/hm~2 using Echinochloa crusgalli, Digiatra sanguinalis, Setaria viridis, Annual bluegrass, Brassica juncea, Amaranthus retroflexus and Chenopodium album as inhibition target. Then, in the two series of IV and V, many compounds showed very good herbicides activity, such as Y6775, Y6776, Y6777, Y6778, Y6795, Y67CN2 and Y67CN7, which also were highly effective (inhibition ratio is higher than 80%) and had broad spectrum. Especially the compound Y6795 showed good inhibition (more than 80%) toward Setaria viridis, Chenopodium album and Amaranthus retroflexus with further screening experiment at a low using concentration of 37.5 g/hm~2. Meanwhile, it is safe to rape after the safety evaluation and more details would be found in furture. Right now, the evaluation of the safety of Y67CN2 and Y67CN7 toward plants are being studying. Series of I and II, none special bioactivity was found of the frame construction and its related structures. So we hope this will be improved with further modification of the frame construction. The herbicides activity test of series III, VI and VII are progressing. More, via the enzymatic assay (AHAS) of the IV type compounds, some of these compounds exhibited high enzyme inhibitory activity, and the symptoms like the plant leaf cupping, crinkling, bronzing and necrosis were found during the against weeds test which was the typical symptoms of AHAS inhibitor.更多还原