Design,Synthesis And Herbicidal Activity Of Novel Ppo Inhibitors Containing Aryl Pyrazole Moeity

Protoporphyrinogen oxidase(PPO)inhibitor is characterized by high effectivity,low toxicity and environmental friendly,it inhibits the enzyme catalyzing the synthesis of chlorophyll in plant cell,allows good selectivity between plants and animals.In this paper,we used the method of active structural combining and bioisosterism means,based on the commercialization PPO inhibitor fluazolate,designed and synthesized two class of structure benzothiazole and 5-thio-acetamide which contants 60 target molecules.The first activity screening shown that some compounds having a good activity in the low dosage at 37.5 g.ai/ha,which are worthy of further optimizing.The specific research works are as follows:1.Generally summarize the PPO-inhibiting herbicides and the biological activity of pyrazole derivative's.2.Designed and synthesized two class of structure which contants 60 target molecules.All novel compounds are characterized by 1H NMR,ESI-MS and element analysis.3.The in vitro PPO inhibition of these newly target compounds were assayed and the further greenhouse herbicidal activity experiment and crop safety were also investigated.The results as follows:The bioassay results indicate that some coumpounds show good PPO inhibition.All these compounds such as benzothiazole compounds Y13519(5.7nM)?Y13522(7.4nM)and 5-thio-acetamide compounds Y14349 displayed higher PPO inhibition than commercialized PPO-inhibiting herbicides sulfentrazone(0.027 ?M).All of these compounds,in selective aspects on tobacco PPO and human sources,the compound Y13519 have 4543 times in selective multiples,far higher than the contrast agent sulfonyl triadimefon(33 times)and isopropyl ether(84 times),this is the highest one compounds for tobacco PPO and the human body in selectivity.The greenhouse biologogical results indicate that a number of benzothiazole compounds show good activity in the post-emergence control of broadleaf weeds(80-100%),such as compounds Y13521?Y13523?Y13529?Y13530?Y13531?Y14184 still have good activity in the post-emergence control of broadleaf weeds at the dosage 37.5 g.ai/ha.When the dosage at 150 g.ai/ha,these compounds Y14177?Y14178?Y14181?Y14183?Y14184 show the good crop safety for wheat.5-thio-acetamide compounds Y14271 and Y14279 shows good activity in the post-emergence control of broadleaf weeds(100%).When the dosage at 37.5 g.ai/ha,these two compounds still have a good activity.The compounds Y14279 show the good crop safety for maize.4.The preliminary structure-activity relationships of benzothiazoles and 5-thio-acetamides were summarized.The path way for further optimization of these PPO inhibitors is undergoing...