Development of Novel (+)-Nootkatone Thioethers Containing 1,3,4-Oxadiazole/Thiadiazole Moieties as Insecticide Candidates against Three Species of Insect Pests

• DOI: 10.1021/acs.jafc.1c05853
• Publication Date: 2021-12-17T19:51:35Z
• Authors: Ruige Yang; Meiyue Han; Jiangping Fan; Wanqing Cheng; Nannan Ma; Xiaoting Yan; Yong Guo
• Keywords: 13 position; Insecticides; relatively low toxicity; (+)- nootkatone; plutella xylostella linnaeus; (+)- nootkatone derivatives; 590; Moths; Biochemistry; Environmental Sciences not elsewhere classified; good selectivity; control efficacy; precursor (+)- nootkatone; insecticidal activities; pot experiments; Oxadiazoles; 0303 health sciences; Ecology; best growth inhibitory; insect pests; Molecular Structure; 27 mg; denticulata fries; 3. Good health; Infectious Diseases; active derivatives; Larva; nontarget organisms; Biotechnology; Chemical Sciences not elsewhere classified; 28 mg; commercial insecticidal etoxazole; greenhouse conditions; insecticide candidates; slightly higher; Sulfides; results indicate; insecticidal activity; Structure-Activity Relationship; 03 medical and health sciences; mythimna separata walker; Thiadiazoles; myzus persicae sulzer; also displayed; Animals; three species; 8s </ b; insecticidal evaluation revealed; 8c </ b; 52e cells; toxicity assays indicated; Polycyclic Sesquiterpenes; title derivatives exhibited; 50 </ sub; Cell Biology; normal mammalian nrk; potent insecticidal activities; potent aphicidal activity; best larvicidal activity; friendly pesticides; Neuroscience; Developmental Biology; new lead compounds; potential eco

To improve the insecticidal activity of (+)-nootkatone, a series of 42 (+)-nootkatone thioethers containing 1,3,4-oxadiazole/thiadiazole moieties were prepared to evaluate their insecticidal activities against Mythimna separata Walker, Myzus persicae Sulzer, and Plutella xylostella Linnaeus. Insecticidal evaluation revealed that most of the title derivatives exhibited more potent insecticidal activities than the precursor (+)-nootkatone after the introduction of 1,3,4-oxadiazole/thiadiazole on (+)-nootkatone. Among all of the (+)-nootkatone derivatives, compound 8c (1 mg/mL) exhibited the best growth inhibitory (GI) activity against M. separata with a final corrected mortality rate (CMR) of 71.4%, which was 1.54- and 1.43-fold that of (+)-nootkatone and toosendanin, respectively; 8c also displayed the most potent aphicidal activity against M. persicae with an LD50 value of 0.030 μg/larvae, which was closer to that of the commercial insecticidal etoxazole (0.026 μg/larvae); and 8s showed the best larvicidal activity against P. xylostella with an LC50 value of 0.27 mg/mL, which was 3.37-fold that of toosendanin and slightly higher than that of etoxazole (0.28 mg/mL). Furthermore, the control efficacy of 8s against P. xylostella in the pot experiments under greenhouse conditions was better than that of etoxazole. Structure-activity relationships (SARs) revealed that in most cases, the introduction of 1,3,4-oxadiazole/thiadiazole containing halophenyl groups at the C-13 position of (+)-nootkatone could obtain more active derivatives against M. separata, M. persicae, and P. xylostella than those containing other groups. In addition, toxicity assays indicated that these (+)-nootkatone derivatives had good selectivity to insects over nontarget organisms (normal mammalian NRK-52E cells and C. idella and N. denticulata fries) with relatively low toxicity. Therefore, the above results indicate that these (+)-nootkatone derivatives could be further explored as new lead compounds for the development of potential eco-friendly pesticides.