Synthesis, Fungicidal Activity, and Mechanism of Action
of Pyrazole Amide and Ester Derivatives Based on Natural Products l‑Serine and Waltherione Alkaloids
posted on 2021-09-20, 19:04authored byXuewen Hua, Wenrui Liu, Yan Chen, Jing Ru, Shangjing Guo, Xiaobo Yu, Yanhong Cui, Xinghai Liu, Yucheng Gu, Chenmeng Xue, Yi Liu, Junkang Sui, Guiqing Wang
The development of new green fungicides
based on the structural
optimization of natural products can effectively solve the problems
of low safety and high pathogen resistance of traditional fungicides.
In this paper, based on pyrazole amide compound h-I-9 with excellent fungicidal activity discovered in the previous work,
a series of l-serine-derived pyrazole amide and waltherione
alkaloid-derived pyrazole ester derivatives were synthesized. The
structures were successively identified by 1H NMR, 13C NMR, high-resolution mass spectrometry, and X-ray single-crystal
diffraction. The in vitro and in vivo fungicidal activity screening
demonstrated that compound II-5 showed a good inhibition
rate against Physalospora piricola.
A transmission electron microscope and fluorescence microscope observation
further revealed that compound II-5 may cause damage
to the cell membranes and vacuoles, and the hyphae treated with II-5 could produce obvious and easily observed blue fluorescence.
The succinate dehydrogenase (SDH) enzymatic activity and molecular
docking simulation indicated that compounds I-3 and I-4 may be potential SDH inhibitors against Alternaria sp.