Synthesis and Antifungal Activity of N-(Substituted pyridinyl)-1-methyl(phenyl)-3-(trifluoromethyl)-1H-pyrazole-4-carboxamide Derivatives

Abstract

A series of N-(substituted pyridinyl)-1-methyl(phenyl)-3-trifluoromethyl-1H-pyrazole-4-carboxamide derivatives were synthesized. All target compounds were characterized by spectral data (1H-NMR, 13C-NMR, IR, MS) and elemental analysis and were bioassayed in vitro against three kinds of phytopathogenic fungi (Gibberella zeae, Fusarium oxysporum, Cytospora mandshurica). The results showed that some of the synthesized N-(substituted pyridinyl)-1-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxamides exhibited moderate antifungal activities, among which compounds 6a, 6b and 6c displayed more than 50% inhibition activities against G. zeae at 100 µg/mL, which was better than that of the commercial fungicides carboxin and boscalid.

A Rapid Microwave Induced Synthesis of Isonicotinamide Derivatives and their Antifungal Activity

“…The bioassay results have shown that some of them exhibited excellent antifungal activities. [23][24][25][26][27][28] It has been proven that pyridine carboxamide group display fungicidal activity by disrupting the mitochondrial tricarboxylic acid cycle (TCA) through inhibition of the succinate dehydrogenase (SDH) enzyme, also called succinate ubiquinone oxidoreductase (SQR). [29] The most of fungicides are heterocyclic toxic substances which selectively destroy fungal phytopatho-gens ( Figure 1).…”

Design, synthesis and biological evaluation of novel nicotinamide derivatives bearing a substituted pyrazole moiety as potential SDH inhibitors

“…They have a novel structure, high-and broad-spectrum fungicidal activity, 17,18 such as carboxin, boscalid, isopyrazam, penthiopyrad, fluopyram etc. 19,20 Scalliet et al 21 compared the structure-activity of Mycosphaerella graminicola SDH (PDB entry: 2fbw) and several SDHIs via molecular docking, and found the following results: O, N and SDH can form stable hydrogen bonds in amide groups; 22 the pyrazole ring binds more closely to protein compared with pyridine ring; 23 the aromatic ring attached to amino can form a hydrophobic bond and -interaction with corresponding amino acids in the binding pocket of target proteins. 24 The common characteristics of these SDHI compounds can be seen: all compounds contain an amide bond, an acyl group connected to aromatic ring or hydrogen bond acceptor and an amino group connected to an aromatic ring.…”

Synthesis and Bioactivities of Novel 1‐(3‐Chloropyridin‐2‐yl)‐N‐Substituted‐5‐(Trifluoromethyl)‐Pyrazole Carboxamide Derivatives

“…In our previous work , we have demonstrated that 1‐methyl‐(phenyl)‐pyrazole‐carboxamides containing pyridine moiety have moderate fungicidal activities. In order to look for highly active compounds against phytopathogenic microbioorganisms, the methyl or phenyl group at 1‐position of the pyrazolering was replaced with 3‐chloropyridine moiety, and a series of new 1‐(3‐chloropyridin‐2‐yl)‐ N ‐substituted‐5‐(trifluoromethyl)‐pyrazole carboxamide derivatives were synthesized.…”