Novel 4‐pyrazole carboxamide derivatives containing flexible chain motif: design, synthesis and antifungal activity

Abstract

Background In recent years, carboxamide fungicides, targeting succinate dehydrogenase (SDH), have shown highly efficient and broad spectrum fungicidal activity. Structure–activity relationship (SAR) results for these commercial fungicides show that the carboxamide group was a key active group. This is useful information for the discovery of new pyrazole carboxamide derivatives with fungicidal activity. Results Twenty‐seven novel pyrazole carboxamides were designed and synthesized. Their fungicidal activities against Gibberella zeae, Phytophthora infestans, Phytophthora capsici, Rhizoctonia solani, Alternaria solani, Botrytis cinerea, Fusarium oxysporum, Cercospora arachidicola, Sclerotinia sclerotiorum and Physalospora piricola were tested; derivatives possessed excellent inhibitory at 50 mg L−1 in particular. Furthermore, some pyrazole carboxamides exhibited remarkably high activities against Sclerotinia sclerotiorum in vitro with EC50 values of 2.04 to 15.2 μg mL−1. In addition, some compounds also exhibited high activities against Physalospora piricola, Cercospora arachidicola and Phytophthora capsici. Inhibition activities against SDH proved that the designed analogues were effective at the enzyme level. The SAR of these pyrazole carboxamides was studied by using the docking method. Conclusion It is possible that pyrazole carboxamides, which exhibit good activity against Sclerotinia sclerotiorum, can be further optimized as a lead compounds of carboxamide fungicides. © 2019 Society of Chemical Industry

Studies on the novel pyridine sulfide containing SDH based heterocyclic amide fungicide

“…2,3 To date, 23 commercial SDHI fungicides have been approved for plant protection since the first launch of carboxin in 1966, and extensively applied to combat destructive plant fungi, such as Sclerotinia sclerotiorum, Rhizoctonia solani, and Botrytis cinerea. [4][5][6] In most of SDHI fungicides, the amide bonds are directly linked to the aromatic ring and polar moiety ( Fig. 1).…”

Synthesis, Crystal Structure, Antifungal Activity, and Docking Study of Difluoromethyl Pyrazole Derivatives

“…Pyrazole is an important five‐membered heterocycle, which can be found in many drugs or pesticides . In the recent years, lots of succinate dehydrogenase inhibitors contain pyrazole motif , such as penthiopyrad, sedaxane, pydiflumetofen, bixafen, isopyrazam, and pyrapropoyne fluxapyroxad. Chemists are very interested in pyrazole because of its unique biological activity, such as antimicrobial , DPPH radical scavenging , anticancer , antifungal , anti‐inflammatory , nematicidal , and cholinesterases inhibitory activities.…”

Discovery of novel arylthioacetic acid derivatives as 4‐hydroxyphenylpyruvate dioxygenase inhibitors

“…Soybean, canola, cotton, corn, rice, and wheat were selected and underwent crop safety testing. [26][27][28][29] The commercial herbicide mesotrione was selected as a positive control. Of the tested crops, proximately 20 seeds (bud rate ≥ 85%) were sown in composite nutrient soil at a depth of 2 cm and grown at a temperature of 15 to 30°C in a glasshouse.…”

“…13 Studies over the past decades have provided important information on interactions between HPPD enzymes and HPPD inhibitors: 1,3-dicarbonyl and aromatic moieties are an indispensable pharmacophore for potent HPPD inhibition. Many researches [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] in HPPD inhibitors indicated that modification of the aromatic moieties is an effective way to get new derivatives with excellent weed control.…”