- Design, Synthesis, and Study of the Insecticidal Activity of Novel Steroidal 1,3,4-Oxadiazoles
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A series of novel steroidal derivatives with a substituted 1,3,4-oxadiazole structure was designed and synthesized, and the target compounds were evaluated for their insecticidal activity against five aphid species. Most of the tested compounds exhibited potent insecticidal activity against Eriosoma lanigerum (Hausmann), Myzus persicae, and Aphis citricola. Compounds 20g and 24g displayed the highest activity against E. lanigerum, showing LC50 values of 27.6 and 30.4 μg/mL, respectively. Ultrastructural changes in the midgut cells of E. lanigerum were detected by transmission electron microscopy, indicating that these steroidal oxazole derivatives might exert their insecticidal activity by destroying the mitochondria and nuclear membranes in insect midgut cells. Furthermore, a field trial showed that compound 20g exhibited effects similar to those of the positive controls chlorpyrifos and thiamethoxam against E. lanigerum, reaching a control rate of 89.5% at a dose of 200 μg/mL after 21 days. We also investigated the hydrolysis and metabolism of the target compounds in E. lanigerum by assaying the activities of three insecticide-detoxifying enzymes. Compound 20g at 50 μg/mL exhibited inhibitory action on carboxylesterase similar to the known inhibitor triphenyl phosphate. The above results demonstrate the potential of these steroidal oxazole derivatives to be developed as novel pesticides.
- Bai, Hangyu,Jiang, Weiqi,Li, Qi,Li, Tian,Ma, Shichuang,Shi, Baojun,Wu, Wenjun
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p. 11572 - 11581
(2021/10/12)
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- Development of Novel (+)-Nootkatone Thioethers Containing 1,3,4-Oxadiazole/Thiadiazole Moieties as Insecticide Candidates against Three Species of Insect Pests
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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.
- Cheng, Wanqing,Fan, Jiangping,Guo, Yong,Han, Meiyue,Ma, Nannan,Yan, Xiaoting,Yang, Ruige
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p. 15544 - 15553
(2022/01/03)
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- Design and synthesis of new norfloxacin-1,3,4-oxadiazole hybrids as antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA)
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Toward the search of new antibacterial agents to control methicillin-resistant Staphylococcus aureus (MRSA), a class of new norfloxacin-1,3,4-oxadiazole hybrids were designed and synthesized. Antibacterial activities against drug-sensitive bacteria S. aureus and clinical drug resistant isolates of MRSA were evaluated. Compound 5k exhibited excellent antibacterial activities against S. aureus (MIC: 2 μg/mL) and MRSA1–3 (MIC: 0.25–1 μg/mL). The time-kill kinetics demonstrated that compound 5k had an advantage over commonly used antibiotics vancomycin in killing S. aureus and MRSA. Moreover, compound 5k could inhibit the bacteria and destroy their membranes in a short time, and showed very low cytotoxicity to NRK-52E cells. Some interesting structure-activity relationships (SARs) were also discussed. These results indicated that these norfloxacin-1,3,4-oxadiazole hybrids could be further developed into new antibacterial agents against MRSA.
- Guo, Yong,Xu, Ting,Bao, Chongnan,Liu, Zhiyan,Fan, Jiangping,Yang, Ruige,Qin, Shangshang
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- Combretastatin linked 1,3,4-oxadiazole conjugates as a Potent Tubulin Polymerization inhibitors
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A new class of combretastatin linked 1,3,4-oxadiazoles were designed, synthesized and screened for their cytotoxic activity against five human cancer cell lines such as HeLa, DU-145, A549, MDA-MB-231 and B16. These compounds showed significant cytotoxicity with IC50 values in the range 0.118-54.32 μM. Conjugate 5m displayed potent antiproliferative activity against DU-145 cell line. Flow cytometric analysis revealed that these compounds arrested the cell cycle in G2/M phase. Moreover, the tubulin polymerization assay and immunofluorescence analysis indicate that 5m exhibits potent inhibitory effect on the tubulin assembly. Further, DNA fragmentation and Hoecst staining assays confirm that 5m induces apoptosis. Molecular docking studies and competitive binding assay indicated that 5m effectively bind at the colchicine binding site of the tubulin.
- Kamal, Ahmed,Srikanth,Vishnuvardhan,Kumar, G. Bharath,Suresh Babu, Korrapati,Hussaini, S.M. Ali,Kapure, Jeevak Sopanrao,Alarifi, Abdullah
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p. 126 - 136
(2016/03/09)
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- Synthesis, biologicalevaluation, and molecular modeling of (E)-2-aryl-5-styryl-1,3,4-oxadiazolederivatives as acetylcholine esterase inhibitors
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A library of 2,5-disubstituted 1,3,4-oxadiazole derivatives of (E)-2-aryl-5-(3,4,5-trimethoxystyryl)-1,3,4-oxadiazoles 4(a-o) and (E)-2-aryl-5-(2-benzo[d][1,3]dioxol-5-yl)vinyl)-1,3,4-oxadiazoles 5(a-q) were synthesized and evaluated for their in vitro acetylcholinesterase (AChE) inhibitory activity. All the synthesized compounds exhibited moderate to good inhibitory activity toward the AChE enzyme. Among the oxadiazole derivatives examined, compounds 4a, 4g, 5c, and 5m (IC50 values of 24.89, 13.72, 37.65, and 19.63 μM, respectively) were found to be promising inhibitors of AChE. Molecular protein-ligand docking studies were examined for these compounds using GOLD docking software and their binding conformations were determined and the simultaneous interactions mode was also established for the potent derivatives. Springer Science+Business Media 2013.
- Kamal, Ahmed,Shaik, Anver Basha,Reddy, G. Narender,Kumar, C. Ganesh,Joseph, Joveeta,Kumar, G. Bharath,Purushotham, Uppula,Sastry, G. Narahari
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p. 2080 - 2092
(2014/05/06)
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- Regio- and chemoselective C-H chlorination/bromination of electron-deficient arenes by weak coordination and study of relative directing-group abilities
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It's all relative: A practical and efficient PdII-catalyzed regio- and chemoselective chlorination/bromination has been developed for the facile synthesis of a broad range of aromatic chlorides. The reaction demonstrates excellent reactivity, good functional-group tolerance, and high yields. A preliminary study was conducted to evaluate relative directing-group abilities of various functionalities. Copyright
- Sun, Xiuyun,Shan, Gang,Sun, Yonghui,Rao, Yu
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supporting information
p. 4440 - 4444
(2013/05/22)
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- Bicyclic pyrazole compounds as antibacterial agents
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Antibacterial compounds, compositions containing them, and methods of use for the inhibition of bacterial activity and the treatment, prevention or inhibition of bacterial infection.
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Page/Page column 24
(2010/11/24)
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