Novel Pyrazolo[3,4-d]pyrimidin-4-one Derivatives as Potential Antifungal Agents: Design, Synthesis, and Biological Evaluation

Abstract

Plant pathogenic fungi seriously threaten agricultural production. There is an urgent need to develop novel fungicides with low toxicity and high efficiency. In this study, we designed and synthesized 44 pyrazolo­[3,4-d]­pyrimidin-4-one derivatives and evaluated them for their fungicidal activities. The bioassay data revealed that most of the target compounds possessed moderate to high in vitro antifungal activities. Especially compound g22 exhibited remarkable antifungal activity against Sclerotinia sclerotiorum with an EC50 value of 1.25 mg/L, close to that of commercial fungicide boscalid (EC50 = 0.96 mg/L) and fluopyram (EC50 = 1.91 mg/L). Moreover, compound g22 possessed prominent protective activity against S. sclerotiorum in vivo for 24 h (95.23%) and 48 h (93.78%), comparable to positive control boscalid (24 h (96.63%); 48 h (93.23%)). Subsequent studies indicated that compound g22 may impede the growth and reproduction of S. sclerotiorum by affecting the morphology of mycelium, destroying cell membrane integrity, and increasing cell membrane permeability. In addition, the application of compound g22 did not injure the growth or reproduction of Italian bees. This study revealed that compound g22 is expected to be developed for efficient and safe agricultural fungicides.

Discovery of Novel Quinazoline-2-Aminothiazole Hybrids Containing a 4-Piperidinylamide Linker as Potential Fungicides against the Phytopathogenic Fungus Rhizoctonia solani

“…The rupture of fungal cell membranes gives rise to the release of cellular contents, including nucleic acids, carbohydrates, proteins, and other substances . To further evaluate the effect of compound 4y on the fungal cell membrane, the release of cellular contents was measured.…”

“…The rupture of fungal cell membranes gives rise to the release of cellular contents, including nucleic acids, carbohydrates, proteins, and other substances. 49 To further evaluate the effect of compound 4y on the fungal cell membrane, the release of cellular contents was measured. The concentrations of nucleic acids and related proteins in the mycelial suspensions were determined by monitoring the changes in the absorbances at 260 and 280 nm, respectively.…”

Design, Synthesis, and Antimicrobial Activity of Quindoline Derivatives Inspired by the Cryptolepine Alkaloid

“…Plant diseases caused by pathogenic fungi and bacteria lead to enormous yield and economic losses in agricultural production. , For example, Sclerotinia sclerotiorum (S. sclerotiorum) is a devastating necrotrophic plant pathogenic fungus that can cause various plant symptoms such as stem blight, stem canker, stem rot, crown rot, and head rot . The annual yield losses due to S.…”

Discovery of Natural Rosin Derivatives Containing Oxime Ester Moieties as Potential Antifungal Agents to Control Tomato Gray Mold Caused by Botrytis cinerea

“…3 In recent years, the irresponsible use of pesticides has led to the rapid development of plant fungal resistance, which reduces the efficacy of conventional fungicides and introduces great challenges to agricultural production. 4 In addition, the potential hazards of some chemical fungicides to the environment and human health and nontarget species have also attracted serious attention. 5 Therefore, the development of new high-efficiency and lowtoxicity antifungal agents is urgently needed to control B. cinerea.…”

“…The use of traditional chemical fungicides for preventing and controlling gray mold is the first discovered, most convenient, and most effective method . In recent years, the irresponsible use of pesticides has led to the rapid development of plant fungal resistance, which reduces the efficacy of conventional fungicides and introduces great challenges to agricultural production . In addition, the potential hazards of some chemical fungicides to the environment and human health and nontarget species have also attracted serious attention .…”