Tripathi Kailashpati, Kaushik Parshant, Yadav Dinesh Kumar, Kumar Rakesh, Misra Sameer Ranjan, Godara Rajni, Bashyal Bishnu Maya, Rana Virendra Singh, Kumar Rajesh, Yadav Jagdish, Shakil Najam Akhtar
Division of Agricultural Chemicals, ICAR-Indian Agricultural Research Institute, New Delhi, India.
ICAR-National Research Centre on Seed Spices, Ajmer, India.
Pest Manag Sci. 2025 May;81(5):2579-2597. doi: 10.1002/ps.8152. Epub 2024 May 21.
Sheath blight and bakanae disease, prominent among emerging rice ailments, exert a profound impact on rice productivity, causing severe impediments to crop yield. Excessive use of older fungicides may lead to the development of resistance in the pathogen. Indeed, a pressing and immediate need exists for novel, low-toxicity and highly selective fungicides that can effectively combat resistant fungal strains.
A series of 20 isoxazole derivatives were synthesized using alkoxy/halo acetophenones and N,N-dimethylformamidedimethylacetal. These compounds were characterized by various spectroscopic techniques, namely H nuclear magnetic resonance (NMR), C NMR and liquid chromatography-high-resolution mass spectrometry, and were evaluated for their fungicidal activity against Rhizoctonia solani and Fusarium fujikuroi. Compound 5n (5-(2-chlorophenyl) isoxazole) exhibited highest activity (effective dose for 50% inhibition [ED] = 4.43 μg mL) against R. solani, while 5p (5-(2,4-dichloro-2-hydroxylphenyl) isoxazole) exhibited highest activity (ED = 6.7 μg mL) against F. fujikuroi. Two-dimensional quantitative structural-activity relationship (QSAR) analysis, particularly multiple linear regression (MLR) (Model 1), highlighted chi6chain and DistTopo as the key descriptors influencing fungicidal activity. Molecular docking studies revealed the potential of these isoxazole derivatives as novel fungicides targeting sterol 14α-demethylase enzyme, suggesting their importance as crucial intermediates for the development of novel and effective fungicides.
All test compounds were effective in inhibiting both fungi, according to the QSAR model, with various descriptors, such as structural, molecular shape analysis, electronic and thermodynamic, playing an important role. Molecular docking studies confirmed that these compounds can potentially replace commercially available fungicides and help control fungal pathogens in rice crops effectively. © 2024 Society of Chemical Industry.
纹枯病和恶苗病是新兴的水稻病害中较为突出的两种，对水稻生产力产生深远影响，严重阻碍作物产量。过度使用旧的杀菌剂可能导致病原菌产生抗性。事实上，迫切需要新型、低毒且高选择性的杀菌剂来有效对抗抗性真菌菌株。
使用烷氧基/卤代苯乙酮和N,N-二甲基甲酰胺二甲基缩醛合成了一系列20种异恶唑衍生物。这些化合物通过各种光谱技术进行表征，即氢核磁共振（NMR）、碳核磁共振和液相色谱-高分辨质谱，并评估了它们对立枯丝核菌和藤仓赤霉菌的杀菌活性。化合物5n（5-(2-氯苯基)异恶唑）对立枯丝核菌表现出最高活性（50%抑制有效剂量[ED]=4.43μg/mL），而5p（5-(2,4-二氯-2-羟基苯基)异恶唑）对藤仓赤霉菌表现出最高活性（ED=6.7μg/mL）。二维定量构效关系（QSAR）分析，特别是多元线性回归（MLR）（模型1），突出了chi6chain和DistTopo作为影响杀菌活性的关键描述符。分子对接研究揭示了这些异恶唑衍生物作为靶向甾醇14α-脱甲基酶的新型杀菌剂的潜力，表明它们作为新型有效杀菌剂开发的关键中间体的重要性。
根据QSAR模型，所有测试化合物对两种真菌均有效，各种描述符，如结构、分子形状分析、电子和热力学描述符，发挥了重要作用。分子对接研究证实，这些化合物有可能替代市售杀菌剂，并有助于有效控制水稻作物中的真菌病原体。©2024化学工业协会。
