Background:
Oxadiazole fragment is one of the most prevalent structures in biochemicals, especially in the research
of new pesticides. It is necessary to develop new insecticides with different mode of action for the treatment of insecticide
resistance problems. And, it is worth exploring the new active insecticidal lead structures with oxadiazole fragments.
Methods:
We used a "splicing up" method introducing the trifluoromethyl-oxadiazole moiety to 3-(ethylsulfonyl)-pyridine
structure, and replaced the 6-position on the pyridine ring by different substituted amines. Then, a series of novel 3-
(ethylsulfonyl)-pyridines containing trifluoromethyl-oxadiazole moiety were designed and synthesized. All these title compounds
were confirmed by 1H NMR, 13C NMR and ESI-MS.
Results and Discussion:
The primary insecticidal activity results indicated that some of them (A1-A7, A10, A13-A14) exhibited
good mortality against Mythimna separate at 500 mg/L (80-100%), and compounds A13 and A14 have moderate insecticidal
activity against M. separate at 250 mg/L (50-55%).
Discussion:
The bioassay results showed that the designed compounds did not achieve excellent insecticidal activity by introducing
the potential oxadiazole fragment. Therefore, it seems that the special physicochemical properties of the oxadiazole
fragment should be considered in fragment splicing-based design.
Conclusion:
According to the bioassay studies, the results revealed that compounds A13 and A14 which may provide useful
information for further design efficient insecticides.
Effects of Halogen Introduction at the C5 Position of the Imidacloprid Pyridine Ring upon Insecticidal Activity