Fungicidal and nematicidal activities of pyrazolopyrimidine against 14 pathogenic fungi and 3 plant nematodes

To discover novel fungicides or lead compounds, the fungicidal activities of some pyrazolopyrimidine compounds were evaluated. The results showed that compounds R13 and R14 exhibited the broadest-spectrum fungicidal activities. At a concentration of 50 mg/L, they showed over 90 % growth inhibition against 13 fungi. In particular, the EC₅₀ values of compounds R13 and R14 against Botryosphaeria dothidea (B. dothidea) were 2.3 and 1.1 mg/L, respectively, both superior to the commercial fungicide azoxystrobin (18.7 mg/L). Compound R14 not only disrupted the surface morphology of B. dothidea hyphae, but also caused cytoplasmic content leakage and increased membrane permeability by damaging the cell membrane. Compound R7 also exhibited excellent nematicidal activities against Aphelenchoides besseyi (A. besseyi), Ditylenchus destructor (D. destructor), and Bursaphelenchus xylophilus (B. xylophilus). Therefore, pyrazolopyrimidine compounds are promising scaffolds for developing novel agrochemicals with dual fungicidal and nematicidal properties.