Antifungal Activities of Fluorinated Pyrazole Aldehydes on Phytopathogenic Fungi, and Their Effect on Entomopathogenic Nematodes, and Soil-Beneficial Bacteria.

Fluoro-substituted pyrazoles have a wide range of biological activities, such as antibacterial, antiviral, and antifungal activities. The aim of this study was to evaluate the antifungal activities of fluorinated 4,5-dihydro-1-pyrazole derivatives on four phytopathogenic fungi: , , f. sp, and . Moreover, they were tested on two soil beneficial bacteria- and -as well as two entomopathogenic nematodes (EPNs)- and . The molecular docking was performed on the three enzymes responsible for fungal growth, the three plant cell wall-degrading enzymes, and acetylcholinesterase (AChE). The most active compounds against fungi were 2-chlorophenyl derivative () (43.07% of inhibition) and 2,5-dimethoxyphenyl derivative () (42.23% of inhibition), as well as against (46.75% of inhibition). Compounds were shown to be safe for beneficial soil bacteria and nematodes, except for compound on EPN (18.75% mortality), which also showed the strongest inhibition against AChE (79.50% of inhibition). The molecular docking study revealed that antifungal activity is possible through the inhibition of proteinase K, and nematicidal activity is possible through the inhibition of AChE. The fluorinated pyrazole aldehydes are promising components of future plant protection products that could be environmentally and toxicologically acceptable.