Seven-Membered Azabridged Neonicotinoids: Synthesis, Crystal Structure, Insecticidal Assay, and Molecular Docking Studies

To
study the influence of the ring sizes, 37 novel seven-membered
azabridged neonicotinoid analogues were synthesized by reactions of
nitromethylene analogues, succinaldehyde, and aniline hydrochlorides.
Most of the title compounds presented higher insecticidal activities
than that of imidacloprid (IMI), cycloxaprid (CYC), and eight-membered
compounds against cowpea aphid (Aphis craccivora), armyworm (Pseudaletia separata Walker),
and brown planthopper (Nilaparvata lugens), which indicated that introducing the structure of a seven-membered
azabridge could significantly improve the insecticidal activities
of neonicotinoid analogues. Docking study and binding mode analysis
also revealed that introducing methyl group into position 2 of phenyl
ring could increase the hydrophobic interactions with receptor, which
implied that position 2 might be the key site to get high insecticidal
compounds.