Cis New Neonicotinoid Compounds Synthesis And Insecticidal Activity Determination

In order to search the introduction compounds for new pesticide,and to make further researches on the structure-activity relationships(SARs) of the neonicotinoid compounds, we have focused ourattentions on designing novel neonicotinoids in this paper. Two series of30unreported novel neonicotinoid insecticides were designed andsynthesized.(1) On the basis of chain-opening neonicotinoids and theneonicotinoid pharmacophores2-chloro-5-pyridinylmethyl and2-nitroimine, we synthesized fourteen novel nitenpyram derivativespossessing a chiral center adjacent to the aryl group (Ar) by introducingbulky substituents fixed cis-configuration by regarding compoundsnitenpyram, acetylacetone, appropriate aromatic aldehyde as rawmaterials Ia-In.(2) Based on cycle neonicotinoids and the structure ofnitenpyram, sixteen unreported Ⅱa-Ⅱp nitenpyram analoguescontaining a cis-configuration fixed by tetrahydropyrimidine weresynthesized with ethanolamine、nitenpyram and various carboxylic acidas raw materials via a series of esterification and Mannich condensationreactions.The structural formulas of compounds I and Ⅱ are as follows respectively: Complete assignments have been achieved for the titlecompounds by elemental analysis,1H NMR, MS and IR. Meanwhile, theirphysic-chemical properties, spectrum properties, reaction conditionsand synthetic methods were analyzed and discussed as well.In order to investigate the relationships between the structures andproperties of the title compounds, the single crystal of compound Ihwere cultured and confirmed by X-ray diffraction analyses. Additionally,to further explore the influential factors for the bioactivities of our designed nitenpyram analogues.The preliminary biological activities tests of the series targetcompounds were finished in bioassay department, Branch of NationalPesticide R&D South Center of Hangzhou. The results indicated thatsome target compounds of I series have common insecticidal activitiesagainst Nilaparvata lugen and Aphis medicaginis at500mg/L. While,the compounds Ⅱa-Ⅱp afforded the best in vitro inhibitory activityagainst Nilaparvata lugen and Aphis medicaginis at100mg/L, and had100%mortality.