Synthesis and Evaluation of the Fungal Activity of New Pyrazole-Carboxamides Against Colletotrichum gloeosporioides

González-López, Edwin; León-Jaramillo, Jhair; Trilleras, Jorge; Grande-Tovar, Carlos David; Peralta-Ruiz, Yeimmy; Quiroga, Jairo

doi:10.21577/0103-5053.20200092

Cited by 1 publication

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“…The primary mode of action of SDHIs is to inhibit the activity of succinate dehydrogenase (SDH), destroy the tricarboxylic acid cycle, impede the electron transfer of the respiratory chain, and inhibit fungal respiration. , Among the commercial SDHI fungicides, half contain the skeleton of 1-methyl-4-pyrazole carboxamide (Figure ). Further analysis of the types of substitution positions on the pyrazole ring of the 12 commercial fungicides indicated that most types of substituted sites were 1,3-disubstituted or 1,3,5-trisubstituted on the pyrazole ring. − Furthermore, a series of novel pyrazole derivatives containing the active skeleton “5-trifluoromethyl-4-pyrazole carboxamide” were first reported in our previous work. Additional studies on the substituents at the 1-position of the pyrazole ring demonstrated that the substituents of the o -methylbenzene ring and o -trifluoromethyl benzene ring exhibited excellent antifungal activity, and mechanism studies revealed that all active compounds were potential SDHIs. − …”

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Potential Fungicide Candidates: A Dual Action Mode Study of Novel Pyrazole-4-carboxamides against Gibberella zeae

Zhang

Yang

Zhao

et al. 2023

J. Agric. Food Chem.

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Pyrazole carboxamides are a class of traditional succinate dehydrogenase inhibitors (SDHIs) that have developed into a variety of commercialized fungicides. In the present work, a series of novel 1,5-disubstituted-1H-pyrazole-4-carboxamide derivatives were designed and synthesized based on the active backbone of 5-trifluoromethyl-1H-4-pyrazole carboxamide. Bioassay results indicated that some target compounds exhibited excellent in vitro antifungal activities against six phytopathogenic fungi. Notably, the EC 50 values of Y 47 against Gibberella zeae, Nigrospora oryzae, Thanatephorus cucumeris, and Verticillium dahliae were 5.2, 9.2, 12.8, and 17.6 mg/L, respectively. The in vivo protective and curative activities of Y 47 at 100 mg/L against G. zeae on maize were 50.7 and 44.2%, respectively. Three-dimensional quantitative structure−activity relationship (3D-QSAR) analysis revealed that the large steric hindrance and electronegative groups on the 5-position of the pyrazole ring were important for the activity. The IC 50 value of Y 47 against succinate dehydrogenase (SDH) was 7.7 mg/L, superior to fluopyram (24.7 mg/L), which was consistent with the docking results. Morphological studies with fluorescence microscopy (FM) and scanning electron microscopy (SEM) found that Y 47 could affect the membrane integrity of mycelium by inducing endogenous reactive oxygen species (ROS) production and causing peroxidation of cellular lipids, which was further verified by the malondialdehyde (MDA) content. Antifungal mechanism analysis demonstrated that the target compound Y 47 not only had significant SDH inhibition activity but could also affect the membrane integrity of mycelium, exhibiting obvious dual action modes. This research provides a novel approach to the development of traditional SDHIs and their derivatives.

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