Abstract:
Using capsaicin as the lead compound, six series of 204 analogues, including 8 new compounds, were synthesized via
N-acylation reactions using substituted benzylamines as precusors. The title compounds were characterized by
1H NMR. Insecticidal activities of those compounds were determined by the leaf dish method. The results showed that most of the benzylamine derivatives had strong toxicities against the 3
rd Mythimna separata. The mortality rates of compounds
A30 ,
D20 ,
D30 ,
D35 ,
E30 and
F30 were 100% and compounds
D19 ,
D21 ,
D22 ,
D23 ,
D31 and
E31 were more than 90% against the 3
rd larvae at 10 µg/disc after 48 h. The preliminary study of structure-activity relationship indicated that the insecticidal activity of the mono-fluorine substitution on the benzene ring of benzylamine was better than that of the correspounding difluorine substituend compound. The 2-fluorobenzylamine derivatives showed better insecticidal activities than others. Additionally, 2-thiopheneformyl derivative exhibited significant insecticidal activity, which indicated that the acyl group was also an active fragment.