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Updated: Feb 21, 2026

Functionalized Spirocyclic Heterocycle Synthesis and Cytotoxicity Assay
Published on: February 9, 2021
Fluopyram analogues containing a five-membered heterocyclic ring moiety: synthesis, nematicidal activity and
Zhitian Huang1, Shenghong Jing1, Qianyu Huang1
1Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai, People's Republic Of China.
None:
Plant-parasitic nematode (PPNs) infections threaten global crop protection and result in substantial annual losses to agriculture worldwide. However, only a limited number of nematicides are currently available, and drug resistance is becoming a more significant concern. Therefore, there is an urgent need to develop new, highly effective, and environmentally friendly nematicides. This study designed and synthesized forty-two novel fluopyram analogues containing five-membered heterocyclic molecules via a "Ring Replacement" strategy. Results from the nematicidal activity testing showed that all the target compounds showed certain activity against Caenorhabditis elegans. Notably, compound 21r demonstrated an LC50 value of 1.83 mg/L, which is significantly lower than that of the commercial nematicide, tioxazafen, but slightly higher than that of the SDHI nematicide, fluopyram. Enzymatic assays and molecular docking studies identified nematode SDH as the probable molecular target. An ecological and environmental risk assessment was also conducted on the target compound 21r. However, the long-term toxic effects of these compounds on aquatic life remain to be further explored. The study indicates that the thiophene moiety, a five-membered heterocyclic ring system, holds significant potential for developing novel SDHI nematicides. The results provide critical mechanistic insights and lay the groundwork for the development of novel nematicides, which will contribute to improving crop protection strategies in agriculture.
Related Concept Videos
Five-Membered Heterocyclic Aromatic Compounds: Overview
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
ortho–para-Directing Deactivators: Halogens
Nomenclature of Aryl and Heterocyclic Amines
Physical Properties of Amines
Basicity of Heterocyclic Aromatic Amines

