Development of Novel α-Santonin-Based Oxazole Derivatives as Potential Insecticide Candidates

Area of Science:

• Agrochemical research
• Natural product chemistry
• Insect toxicology

Background:

• α-Santonin, a natural product, has historical anthelmintic use but limited agrochemical applications.
• Structural optimization of natural products is crucial for developing new pesticides.
• There is a need for effective and low-toxicity insecticides in agriculture.

Purpose of the Study:

• To design and synthesize novel α-santonin-based oxazole derivatives.
• To evaluate the insecticidal activities of these derivatives against key agricultural pests.
• To explore the preliminary insecticidal mechanism of action.

Main Methods:

• Chemical synthesis of α-santonin-based oxazole derivatives.
• Bioassays for insecticidal, aphicidal, and larvicidal activities against Mythimna separata, Myzus persicae, and Plutella xylostella.
• Greenhouse efficacy trials.
• Preliminary mechanistic studies involving enzyme inhibition (glutathione S-transferase) and molecular docking.

Main Results:

• Compound VII14 demonstrated high efficacy against Mythimna separata (96.3% corrected mortality).
• Several derivatives (VII2, VII5, VII13, VII14, VII16) showed superior aphicidal activity against Myzus persicae compared to rotenone.
• Compounds VII19 and VII20 exhibited potent larvicidal activity against Plutella xylostella, outperforming rotenone.
• Greenhouse studies confirmed the potent insecticidal activity of VII19 and VII20.
• VII19 showed inhibitory effects on glutathione S-transferase in Plutella xylostella, supported by molecular docking.
• The active derivatives displayed good safety towards non-target aquatic organisms.

Conclusions:

• Novel α-santonin-based oxazole derivatives possess significant insecticidal potential.
• These compounds represent promising candidates for developing efficient and low-toxicity green insecticides.
• The study provides a foundation for further development and application of these derivatives in agrochemicals.