Design and synthesis of novel 2,2-dimethylchromene derivatives as potential antifungal agents

In order to find novel environment-friendly and effective antifungal agents, four series of 2,2-dimethyl-2H-chromene derivatives were designed, synthesized and characterized by spectroscopic analysis. The antifungal activities of all the target compounds against nine phytopathogenic fungi were evaluated in vitro. Preliminary results indicated that most of the target compounds exhibited obvious antifungal activity at the concentration of 50 μg/mL. Among them, compound 4j displayed more promising antifungal potency against Fusarium solani, Pyricularia oryzae, Alternaria brassicae, Valsa mali and Alternaria alternata strains than the two commercially available fungicides chlorothalonil and hymexazol, with the corresponding EC₅₀ values of 6.3, 7.7, 7.1, 7.5, 4.0 μg/mL, respectively. Moreover, the cell experiments results suggested that the target compounds had low cytotoxicity to the PC12 cell. This research will provide theoretical basis for the future application of 2,2-dimethyl-2H-chromenes as botanical fungicides in agriculture. Four series of novel, potent and low-toxicity 2,2-dimethyl-2H-chromene derivatives were designed and synthesized as agricultural antifungal agents. The in vitro antifungal experiments showed that compound 4j exhibited higher antifungal efficacy against five strains than the two commercially-available fungicides chlorothalonil and hymexazol.