- The structure modification of seven-membered aza-brigded neonicotinoids in order to investigate their impact on honey bees
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In order to explore the relationship between the structure and the toxicity to honey bees of seven-membered aza-bridged neonicotinoids, 16 novel seven-membered aza-bridged neonicotinoid analogues are synthesized by replacing the pyridine ring, and changing the substituents on the pyridine ring, the electron-withdrawing group NO2 and the imidazole ring of our previously developed aza-bridged neonicotinoid 1-[(6-chloropyridin-3-yl)methyl)]-10-(2,5-dimethylphenyl)-9-nitro-2,3,5,6,7,8-hexahydro-1H-5,8-epiminoimidazo azepine (C-29). The insecticidal bioactivities against cowpea aphid (Aphis craccivora) and the bee toxicities of these compounds are tested. Some of the title compounds present good insecticidal activities against cowpea aphid. The results also show that some of the title compounds exhibit lower bee toxicity than that of C-29 and imidacloprid. This suggests that changing the substituents on the neonicotinoids can influence the toxicity toward honey bees of these analogues.
- Cao, Xiaofeng,Chen, Xi,Chen, Yuce,Li, Zhong,Xu, Xiaoyong
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p. 835 - 844
(2021/05/29)
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- Stability Comparison of Imidacloprid and Related Compounds under Simulated Sunlight, Hydrolysis Conditions, and to Oxygen
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Lipophilicity and the tendency for decomposition fo imidacloprid and related compounds by oxygen, hydrolytic mediums, and simulated sunlight were studied to see whether these physicochemical factors have any relation to the biological activity of the compounds in vitro, in a greenhouse, or under field conditions.Lipophilicity indices based on HPLC bore no definite relationship with the binding affinity to the acetylcholine receptor.However, the compounds having high insecticidal potential in greenhouse tests were generally less hydrophilic.In neutral water or in an oxygen-saturated solution, the compounds tested were completely stable.An evident difference was observed in their behavior toward the sunlight wavelength, the nitromethylene compounds decomposing far more rapidly than nitroimines like imidacloprid.The photolability of the nitromethylenes is ascribed to their longer maximum absorption waveleng of over 32o nm.th
- Kagabu, Shinzo,Medej, Somporn
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p. 980 - 985
(2007/10/02)
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