Synthesis And Biological Activities Of Butenolide Neonicotinoid Insecticides

In the world insecticide market,neonicotinoid insecticides are an important component,and they have been sold worldwide due to their unique and efficient effects.However,the long-term and excessive use of neonicotinoid insecticides worldwide has caused a variety of pests to develop certain resistance to this type of insecticides.In recent years,studies have found that the neonicotinoid insecticides exhibit bee toxicity that seriously threatens the survival of bee colonies,which restricts the application and development of such insecticides.Therefore,it is an urgent task to actively develop new nicotine compounds with novel structure,high efficiency and safety.In this paper,Fluoropyrrolidone,a butenolide neonicotinoid insecticide,was used as the lead compound to synthesize two series of target compounds A and B through reasonable structural modification and improvement,and all compounds are tested for insecticidal activity.1.By introducing fluoroalkoxy and aromaticoxy groups to modify the pharmacophore butenolide,and using the principle of bioelectronic isosteric to introduct a new pharmacophore dithiobutenolide.Using 2-chloro-5-chloromethylpyridine,different fatty amines and benzylamines,viscous halides,fluoroalcohols,dithiobutyrolactone,etc.as raw materials,after substitution,ring bonding,etherification,Michael addition Elimination and other reactions resulted in the synthesis of 44 neonicotinoid compounds containing butenolide active structures which have not been reported in the literature.The structure of all compounds was confirmed by nuclear magnetic resonance hydrogen spectrum,carbon spectrum(¹H NMR,¹³C NMR),and high-resolution mass spectrometry?HRMS?.2.The insecticidal activity of A and B series of compounds was tested by impregnation method.The results showed that the overall insecticidal activity of A series of target compounds was poor.The highest 72 h lethality rate of A series of target compounds to Aphis craccivora Koch was 91.0%at 100 mg/L,which was lower than Flupyradifurone.All compounds in the B series showed good insecticidal activity against Aphis craccivora Koch.The compounds B01,B02,B15?B17,B19,B20 had a lethality rate of 100%for Aphis craccivora Koch at 100 mg/L for 48 h,which was comparable to the lethality rate of Flupyradifurone at the same concentration.The above compounds were re-screened at 20 mg/L and 4 mg/L.The results showed that compounds B16 and B19 still showed excellent insecticidal activity at low concentrations,and the lethality of compound B16 to Aphis craccivora Koch at a concentration of 20 mg/L and 4 mg/L reached 100%and 97.4%,which was equivalent to the Flupyradifurone.It can be used as a new neonicotinine lead compound with new structure for further research and exploration.