Trifluoromethylpyridine thiourea derivatives: design, synthesis and inhibition of the self-assembly of tobacco mosaic virus particles

Enhancing plant resistance to tobacco mosaic virus through the combined application of Verticillium dahliae Aspf2-like protein and microelements

BACKGROUND

Tobacco mosaic virus (TMV) poses a significant threat to global agriculture, infecting economically vital crops such as tobacco, tomato, pepper, and potato. Previous studies have suggested that the Verticillium dahliae Aspf2-like protein (VDAL) enhances plant resistance to TMV. This study investigated the preventive and therapeutic effects of VDAL, with and without microelements, on TMV resistance by analyzing plant hormone levels, defense related enzyme activities, and transcriptomic responses.

RESULTS

Plants were subjected to six experimental treatments: CK0 (untreated control, no TMV or VDAL treatment), CK (TMV inoculated control), T1 (preventive VDAL treatment), T2 (preventive VDAL + microelements), CT1 (therapeutic VDAL treatment), and CT2 (therapeutic VDAL + microelements). TMV inoculation (CK) significantly increased (P < 0.05) TMV content, jasmonic acid (JA), salicylic acid (SA) levels, and activities of defense related enzymes, including benzoic acid 2-hydroxylase (BA2H), peroxidase (POD), polyphenol oxidase (PPO), and superoxide dismutase (SOD), compared to CK0. Both preventive treatments (T1 and T2) effectively reduced TMV content and enhanced JA, SA, and defense related enzyme activities. Notably, the microelement-supplemented preventive treatment (T2) showed 37.73% greater reduction in TMV content compared to T1. Similarly, the therapeutic applications, CT2 reduced the TMV content by 32.50% than CT1. Treatments T2 and CT2 also increased the contents of JA by 5.48% and 2.88%, respectively compared to their respective controls. Transcriptomic analysis revealed that these treatments activated plant-pathogen interaction pathways and pathogen-associated molecular pattern-triggered immunity (PTI), with significant upregulation of key defense related genes (e.g., CALM, BAK1, PTI6, and WRKY33), indicating a robust antiviral defense response.

CONCLUSION

Overall, we conclude that the synergistic application of VDAL and microelements significantly enhances plant resistance to TMV through coordinated activation of phytohormone signaling, defense enzymes, and immune-related gene expression. This combined approach offers an effective, eco-friendly alternative for sustainable management of viral diseases in agricultural crops. © 2025 Society of Chemical Industry.

Thiourea Derivatives in Agrochemical Discovery and Development

Thiourea, represented by the chemical formula (R1R2N)(R3R4N)C═S, is a significant organic sulfur compound characterized by the presence of a sulfur atom and two amino groups. Meanwhile, thiourea and isothiourea are reciprocal isomers. This structure facilitates the formation of a biologically active moiety, which is interconnected through double bonds between the sulfur atom and the nitrogen atoms. As a potent component in pesticide formulations, thiourea demonstrates efficacy in safeguarding crops against a variety of diseases by inhibiting the growth and reproduction of pathogens. This review aims to provide a comprehensive summary of thiourea derivatives exhibiting fungicidal, insecticidal, antiviral, herbicidal, and plant growth regulatory properties, with the objective of offering new perspectives for identifying innovative thiourea-based pesticides and elucidating their mechanisms of action.

Acyl hydrazone derivatives with trifluoromethylpyridine as potential agrochemical for controlling plant diseases

BACKGROUND

Crops are consistently under siege by a multitude of pathogens. These pathogenic microorganisms, including viruses and bacteria, result in substantial reductions in quality and yield globally by inducing detrimental crop diseases, thus posing a significant challenge to global food security. However, the biological activity sepectrum of commercially available pesticides is limited and the pesticide efficacy is poor, necessitating the urgent development of broad-spectrum and efficient strategies for crop disease prevention and control.

RESULTS

The bioassay results revealed that certain target compounds demonstrated outstanding in vivo antiviral efficacy against cucumber mosaic virus and tobacco mosaic virus. In particular, compound D6 showed remarkable antiviral activity against CMV, significantly higher than that of the control agent ningnanmycin. Mechanism of action studies have shown that compound D6 could enhance the activity of defense enzymes and upregulate the expression of genes related to disease resistance, thereby enhancing the antiviral effects in plants. In addition, these compounds displayed superior inhibitory activity against plant bacterial diseases. For Xoo, compound D10 showed an excellent inhibitory effect that was better than that of the control agent bismerthiazol. Scanning electron microscopy and fluorescence double-staining experiments revealed that compound D10 effectively inhibited bacterial growth by disrupting the cell membrane.

CONCLUSION

A series of trifluoromethyl hydrazone derivatives were designed and synthesized, and it was found that they have control effects on plant viruses and bacterial diseases. In addition, this study revealed the mechanism of action of the active compounds and demonstrated their potential as multifunctional crop protectants. © 2024 Society of Chemical Industry.

New Prospective Insecticidal Agents Based on N-(arylcarbamothioyl)arylmide Derivatives Against Spodoptera frugiperda: Design, Synthesis, Toxicological, Biological, Biomedical Studies and Antibacterial Activity

In this work, a novel series of N-(arylcarbamothioyl)arylmide) 2-11 were synthesized by treating One-Pot three-multicomponent of Aroyl chloride, ammonium isothiocyanate and amine compounds under refluxing conditions. Using spectroscopic methods, the chemical structure of the novelty developed compounds were investigated. After five days, the proposed derivatives' insecticidal bioassay was assessed using the median lethal concentration (LC50) against the second & fourth larvae of Spodoptera frugiperda as toxicity agents. The findings showed that, to varying degrees, every tested substance exerted insecticidal effects on S. frugiperda larvae in both of their instars. Compound 9 was the most poisonous of them all, having an LC50 against larvae in their second and fourth instars of 60.45 and 123.21 mg/L, respectively. Additionally, a few biological and biochemical characteristics of the substances that were generated in a lab setting were also looked at. Furthermore, this work discusses how to discover novel compounds that may one day be employed as insecticidal agents. Finally, all the designed components were monitored for their antibacterial effectiveness toward both Gram-positive & Gram-negative bacteria.

Application of Difluoromethyl Isosteres in the Design of Pesticide Active Molecules

Difluoromethyl (CF2H) groups have been found in many listed pesticides due to their unique physical and chemical properties and outstanding biological activity. In pesticide molecules, compared with the drastic changes brought by trifluoromethyl, difluoromethyl usually moderately regulates the metabolic stability, lipophilicity, bioavailability, and binding affinity of compounds. Therefore, difluoromethylation has become an effective means to modify the biological activity of pesticide molecules. This paper reviews the representative literatures and patents containing difluoromethyl groups in the past 10 years, and introduces the research progress. The aim is to provide an effective reference value for the study of difluoromethyl in pesticides.

3D-QSAR model-oriented optimization of Pyrazole β-Ketonitrile derivatives with diphenyl ether moiety as novel potent succinate dehydrogenase inhibitors

BACKGROUND

Succinate dehydrogenase inhibitor (SDHI) fungicides play important roles in the control of plant fungal diseases. However, they are facing serious challenges from issues with resistance and cross-resistance, primarily attributed to their frequent application and structural similarities. There is an urgent need to design and develop SDHI fungicides with novel structures.

RESULTS

Aiming to discover novel potent SDHI fungicides, 31 innovative pyrazole β-ketonitrile derivatives with diphenyl ether moiety were rationally designed and synthesized, which were guided by a 3D-QSAR model from our previous study. The optimal target compound A23 exhibited not only outstanding in vitro inhibitory activities against Rhizoctonia solani with a half-maximal effective concentration (EC50) value of 0.0398 μg mL-1 comparable to that for fluxapyroxad (EC50 = 0.0375 μg mL-1), but also a moderate protective efficacy in vivo against rice sheath blight. Porcine succinate dehydrogenase (SDH) enzymatic inhibitory assay revealed that A23 is a potent inhibitor of SDH, with a half-maximal inhibitory concentration of 0.0425 μm. Docking study within R. solani SDH indicated that A23 effectively binds into the ubiquinone site mainly through hydrogen-bonds, and cation-π and π-π interactions.

CONCLUSION

The identified β-ketonitrile compound A23 containing diphenyl ether moiety is a potent SDH inhibitor, which might be a good lead for novel fungicide research and optimization. © 2024 Society of Chemical Industry.

Synthesis of 4H-Pyrazolo[3,4-d]pyrimidin-4-one Hydrazine Derivatives as a Potential Inhibitor for the Self-Assembly of TMV Particles

Tobacco mosaic virus coat protein (TMV-CP), as a potential target for the development of antiviral agents, can assist in the long-distance movement of viruses and plays an extremely important role in virus replication and propagation. This work focuses on the synthesis and the action mechanism of novel 4H-pyrazolo[3,4-d] pyrimidin-4-one hydrazine derivatives. The synthesized compounds exhibited promising antiviral activity on TMV. Specifically, compound G2 exhibited high inactivating activity (93%) toward TMV, slightly better than commercial reagent NNM (90%). The action of mechanism was further explored by employed molecular docking, molecular dynamics simulation, microscale thermophoresis, qRT-PCR, and transmission electron microscopy. Results indicated that G2 had the capability to interact with amino acid residues such as Trp352, Tyr139, and Asn73 in the active pocket of TMV-CP, creating strong hydrophobic interactions and thus obstructing the virus's self-assembly.

Identification of natural Rutaecarpine as a potent tobacco mosaic virus (TMV) helicase candidate for managing intractable plant viral diseases

BACKGROUND

Naturally occurring alkaloids are particularly suitable for use as pesticide precursors and further modifications due to their cost-effectiveness, unique mechanism of action, tolerable degradation, and environmental friendliness. The famous tobacco mosaic virus (TMV) is a persistent plant pathogenic virus that can parasitize many plants and severely reduce crop production. To treat TMV disease, TMV helicase acts as a crucial target by hydrolyzing adenosine triphosphate (ATP) to provide energy for double-stranded RNA unwinding.

RESULTS

To seek novel framework alkaloid leads targeting TMV helicase, this work successfully established an efficient screening platform for TMV helicase inhibitors based on natural alkaloids. In vivo activity screening, enzyme activity detection, and binding assays showed that Rutaecarpine from Evodia rutaecarpa (Juss.) Benth exhibited excellent TMV helicase inhibitory properties [dissociation constant (Kd ) = 1.1 μm, half maximal inhibitory concentration (IC50 ) = 227.24 μm] and excellent anti-TMV ability. Molecular docking and dynamic simulations depicted that Rutaecarpine could stably bind in active pockets of helicase with low binding energy (ΔGbind  = -17.8 kcal/mol) driven by hydrogen bonding and hydrophobic interactions.

CONCLUSION

Given Rutaecarpine's laudable bioactivity and structural modifiability, it can serve as a privileged building block for further pesticide discovery.

Discovery of Chiral Diamine Derivatives Containing 1,2-Diphenylethylenediamine as Novel Antiviral and Fungicidal Agents

Severe plant virus diseases lead to poor harvests and poor crop quality, and the lack of effective suppressive drugs makes plant disease control a huge challenge. Natural product-based structural simplification is an important strategy for finding novel pesticide candidates. According to our previous research on the antiviral activities of harmine and tetrahydroharmine derivatives, a series of chiral diamine compounds were designed and synthesized by means of structural simplification using diamines in natural products as the core structure in this work, and the antiviral and fungicidal activities were investigated. Most of these compounds displayed higher antiviral activities than those of ribavirin. Compounds 1a and 4g displayed higher antiviral activities than ningnanmycin at 500 μg/mL. The antiviral mechanism research revealed that compounds 1a and 4g could inhibit virus assembly by binding to tobacco mosaic virus (TMV) CP and interfere with the assembly process of TMV CP and RNA via transmission electron microscopy and molecular docking. Further fungicidal activity tests showed that these compounds displayed broad-spectrum fungicidal activities. Compounds 3a, 3i, 5c, and 5d with excellent fungicidal activities against Fusarium oxysporum f.sp. cucumerinum can be considered as new fungicidal candidates for further research. The current work provides a reference to the development of agricultural active ingredients in crop protection.

Trifluoromethylpyridine piperazine derivatives: synthesis and anti-plant virus activity

BACKGROUND

The cucumber mosaic virus (CMV) is well-known for its expansive host range and distribution, resulting in a detrimental effect on agricultural production, thus making it imperative to implement measures for its control.

RESULTS

Novel compounds S1-S28 were synthesized by connecting trifluoromethyl pyridine, amide and piperazine scaffolds. Bioassays indicated that most of the synthesized compounds exhibited good curative effects against CMV, with half maximal effective concentration (EC₅₀ ) values of compounds S1, S2, S7, S8, S10, S11, S15, and S28 being 119.6, 168.9, 197.6, 169.1, 97.9, 73.9, 224.4, and 125.2 μg mL^-1 , respectively, which were lower than the EC₅₀ of ningnanmycin (314.7 μg mL^-1 ). Compounds S5 and S8 exhibited protective activities with EC₅₀ of 170.8 and 95.0 μg mL^-1 , respectively, which were lower than ningnanmycin at 171.4 μg mL^-1 . The inactivation activities of S6 and S8 at 500 μg mL^-1 were remarkably high at 66.1% and 78.3%, respectively, surpassing that of ningnanmycin (63.5%). Additionally, their EC₅₀ values were more favorable at 22.2 and 18.1 μg mL^-1 , respectively, than ningnanmycin (38.4 μg mL^-1 ). And molecular docking and molecular dynamics simulation showed compound S8 had better binding with CMV-coat protein, providing a possible explanation for the anti-CMV activity of compound S8.

CONCLUSIONS

Compound S8 showed a strong binding affinity to CMV-coat protein and impacted the self-assemble of CMV particles. Compound S8 could be a potential lead compound for discovering a new anti-plant virus candidate. © 2023 Society of Chemical Industry.

Systematic Study on Turpentine-Derived Amides from Natural Plant Monoterpenes as Potential Antifungal Candidates

To overcome the high volatility, low aqueous solubility, and few definite action sites of monoterpenoid pesticides and improve their properties and effectiveness in the control of crop pathogenic fungi, herein, a series of natural turpentine-based amide derivatives exhibiting satisfactory antifungal activity were designed and synthesized. A systematic study was conducted on antifungal activity and the physiological and biochemical response of compounds 5o (EC₅₀ = 1.139 μg/mL) and 5j (EC₅₀ = 1.762 μg/mL) against Rhizoctonia solani. The effect of the target compound on the potential target-site succinate dehydrogenase was evaluated. The soluble concentrates of compounds 5o and 5j possessing good performance and control effects were prepared for practical application. To conduct a comprehensive analysis of the relationship between structural descriptors and activity, four representative title compounds were selected for theoretical calculation: 5o, 5j, 5k, and 5j. The binding mode of compound 5o and boscalid with succinate dehydrogenase was analyzed via molecular docking. This study provides a reference for the development of monoterpene pesticides with high efficiency, elucidated target sites, and the appropriate formula.

Novel trifluoromethylpyridine piperazine derivatives as potential plant activators

Plant virus diseases seriously affect crop yield, especially tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV). The development of plant immune activators has been an important direction in the innovation of new pesticides. Therefore, we designed and synthesized a series of trifluoromethyl pyridine piperazine derivatives (A1-A27), and explored the action mechanism of active compound. The antiviral activity test showed that compounds A1, A2, A3, A9, A10, A16, A17 and A21 possessed higher activities than commercialized ningnanmycin. Particularly, the in vivo antiviral activity indicated that compound A16 showed the most potent protective activity toward TMV (EC50 = 18.4 μg/mL) and CMV (EC50 = 347.8 μg/mL), compared to ningnanmycin (50.2 μg /mL for TMV, 359.6 μg/mL for CMV). The activities of defense enzyme, label -free proteomic and qRT-PCR analysis showed that compound A16 could enhance the defensive enzyme activities of superoxide dismutase (SOD),polyphenol oxidase (PPO) and phenylalanine ammonialyase (PAL), and activate the phenylpropanoid biosynthesis pathway to strenthen the antiviral activities of tobacco. This study provides reliable support for the development of new antiviral pesticides and potential antiviral mechanism.

Trifluoromethylpyridine: An Important Active Fragment for the Discovery of New Pesticides

Trifluoromethylpyridine (TFMP) is a biologically active fragment formed by connecting trifluoromethyl and pyridine ring. As a result of its unique physical and chemical properties and outstanding biological activity, a variety of pesticide compounds with the TFMP fragment have been discovered and marketed and have played important roles in crop protection research. It is therefore a timely and valuable task to summarize the rationality on how to create new molecules containing TFMP fragments based on the structure-activity relationships, design mentality, and potential mechanism. This review gives a brief summary on the pesticides containing TFMP fragments in the past 5 years and introduces the latest progress of our group in this field. The aim is to provide readers with a convenient route to touch this topic and hopefully serve some educational purpose for graduate students as well.