Study On Synthesis And Activity Of Novel Compounds With Pesticidal Activities By The Method Of Cluster Effect And Me-too

Pesticide is an important guarantee for agricultural production and plays an important role in national economic development. New pesticidal varieties with high activity, low toxicity and safety have been a trend in the 21st century. To find novel compounds with pesticidal activities, we have synthesized 4 novel series of compounds by the methods of cluster effect and me-too, and evaluated their bioactivities in this study. It mainly contains two parts as bellow:Part I: Synthesis of dual binding site inhibitors by cluster effect1,Based on the two binding sites of AHAS, 8 symmetrical bivalent molecules of imazapic were designed and synthesized. The preliminary bioassay results showed that the inhibition rate to the AHAS from dimeric compounds were less potent than that of imazapic. And the inhibition rate to the growth of rape (Brassica campestris L.) root from bivalent compounds were very close to that of imazapic at the concentration of 100μg mL-1.2,Based on catalytic triad and hydrophobic sites of AChE, 31 dimeric compounds were designed and synthesized. Their activities results in vitro showed that compounds B10,B11,B25,B26,B28 and B29 had better AChE inhibitory activities than pheny N-methylcarbamate (MH). Among them, compound B29 displayed the best AChE inhibitory activity with 62-fold higher than MH and 12-fold higher than metolcarb, which suggested that the phenoxy group bound strongly to the residues lining the gorge, the phenyl carbamate group bound at the catalytic sites. The results obtained from these studies demonstrated the feasibility of the cluster effect in the pesticide field.Part II: Synthesis of the novel pyrazole derivatives by me-too method.1,Using new pesticide pyroxasulfone, currently under commercial development, as lead compound, 14 novel compounds were designed and synthesized. The herbicidal bioassay results showed that these pyrazole derivatives (C1-C6) inhibited root and shoot elongation of the germinated seed of Echinochloa crusgalli L., Digitaria sanguinalis L., and Portulaca oleracea L. at the concentration of 100μg mL-1. In greenhouse conditions, compounds C1-C6 showed better herbicidal activities against monocotyledonous weeds in pre-emergence treatment than metolachlor. Among them, compound C4 showed best inhibitory activity against both dicotyledonous and monocotyledonous weeds with good safety to maize and rape. Field trials indicated that compound C4 exhibited better herbicidal activity by soil application than the commercial herbicide, metolachlor. Moreover, compound C4 showed the same level of safety to maize as metolachlor. Consequently, compound C4 possessed excellent herbicidal activity and selectivity and deserved further studies as the herbicide candidate in a maize field.2,By the introduction of alkyne and pyrimidine moieties into pyrazole ring, we have designed and synthesized 31 novel pyrazole derivatives and evaluated their herbicidal activites. The preliminary bioassay results showed these compounds inhibited root and shoot elongation of the germinated seed of Echinochloa crusgalli L., Digitaria sanguinalis L., and rape. Compounds D13-16, D18, D21, D22 and D24 exhibited excellent bleaching herbicidal activities and deserved further studies.