Design, synthesis and aphicidal activity of N-terminal modified insect kinin analogs

A series of N-terminal modified insect kinin analogs were designed and synthesized based on the lead compound [Aib]-Phe-Phe-[Aib]-Trp-Gly-NH2. All the analogs showed aphicidal activity against Aphis glycines. In particular, the pentapeptide analog X (LC50 = 0.045 mmol/L) has similar activity to the lead (LC50 = 0.048 mmol/L). This indicated that the N-terminal protective group may not play an important role in activity and the structure might be further simplified.