Synthesis and antifungal activity of hexahydropyrrolidoindole alkaloids

Twenty-one hexahydropyrrolidoindole alkaloids were designed and synthesised via acylation reaction at the 3-N position from the commercially available indole-3-acetonitrile as the starting material in excellent yields. The effects of all target compounds against Verticillium dahlia, Fusarium oxysperium sp., Cytospora juglandis, Aspergillu sflavu, Aspergillus niger and Fusarium oxysporum were determined. The results of bioassays indicated that the majority of tested compounds displayed comparable or better in vitro bioactivity than the positive control. Notably, compounds 8 and 17 revealed potent activity against C. juglandis and A. sflavu, both with the same minimum inhibitory concentration value of 1.9 µg mL−1, which has fungicidal activity far exceeded that of amphotericin B and chlorothalonil.