Synthesis and structure-activity relationship of β-carboline derivatives with antifungal activity.

To search for and screen out effective antifungal lead compounds applicable to agriculture, a total of 21 tetrahydro-β-carboline derivatives were designed, synthesised, and evaluated for their antifungal activity. Based on biological studies, numerous compounds demonstrate notable antifungal properties in vitro. Specifically, compounds a6 and a20 showed higher efficacy against Sclerotinia sclerotiorum compared to carbendazim, with EC50 values of 16.43 mg/L and 12.72 mg/L, respectively. Additionally, compound a16 exhibited exceptional antifungal activity against both S. sclerotiorum and Botrytis cinerea, achieving identical EC50 values of 12.71 mg/L for both pathogens. The results of this study will give reference for the additional design and structural optimisation of β-carboalkaloids as possible agrochemical lead compounds for plant disease control.