Abstract:
To further enhance the utility of osthole, we designed and synthesized 26 novel osthole derivatives containing the 1,3,4-oxadiazol-2-ylsulfenyl fragment, and measured their insecticidal and acaricidal activities. Meanwhile, through scanning electron microscope (SEM), the effects of compound
6h on the cuticle layer of
Tetranychus cinnabarinus Boisduval were observed. The results shown that compound
6h (R=3-OCH
3Ph) exhibited the highest acaricidal activity against female adults of
T. cinnabarinus with a 72 h LC
50 value of 0.466 mg/mL, which was 2.6-fold activity of osthole (LC
50 value 1.200 mg/mL); compounds
6u (R=4-CF
3Ph) and
6v (R=3-CNPh) displayed the most potent insecticidal activity against the 3rd instar larvae of
Plutella xyllostella Linnaeus with 48 h LC
50 values of 0.617 and 0.853 mg/mL, respectively; compound
6u showed 2.4-fold insecticidal activity of osthole (LC
50 value 1.503 mg/mL). The SEM results showed that the cuticle layer of female adults of
T. cinnabarinus was folded and collapsed within 24 h after treatment with compound
6h , and this distinct symptom persisted over time. Overall, this study establishes a framework for the application of osthole derivatives as acaricidal and insecticidal agents.