Novel quinoxalinone-1,2,3-triazole derivatives as potential antifungal agents for plant anthrax disease: Design, synthesis, antifungal activity and SAR study

A series of quinoxalinone-1,2,3-triazole derivatives have been synthesized and tested for antifungal activity against phytopathogenic fungus through mycelial growth inhibition in vitro, spore germination inhibition in vitro and control effect in vivo. The results showed that the pharmacophore quinoxalinone and 1,2,3-triazole displayed promising antifungal activity. The EC50 value against C. gloeosporioides of 6a-1 was 1.17 μg/mL and the compound 6c-1 showed the good bioactivity against C. fragariae Brooks and P. oryzae Cav., displaying EC50 values of 5.56, 4.62 μg/mL, respectively. The inhibitory of spore germination by 6a-1 was performed with EC50 value of 1.91 μg/mL. In addition, the in vivo bioassay indicated that 6a-1 possessed effective control against Pepper Anthrax Disease in protective treatment. For given activity data of target compounds, structure-activity relationship (SAR) study was operated, hoping for optimizing the target structure to find lead compound with higher activity.