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

J Agric Food Chem. 2021 Sep 29;69(38):11395-11405. doi: 10.1021/acs.jafc.1c02454. Epub 2021 Sep 15.

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.

Keywords: Italian bees; Sclerotinia sclerotiorum; fungicidal activity; pyrazolo[3,4-d]pyrimidin-4-one.

MeSH terms

  • Animals
  • Antifungal Agents / pharmacology
  • Ascomycota*
  • Fungicides, Industrial* / pharmacology
  • Structure-Activity Relationship

Substances

  • Antifungal Agents
  • Fungicides, Industrial

Supplementary concepts

  • Sclerotinia sclerotiorum