Design, synthesis, and antifungal activity of 14-aryloxy/amide substituted andrographolide derivatives

Abstract In order to find more compounds with antifungal activities, a series of new compounds were designed and synthesized using the natural product of diterpenoid lactones, andrographolide, as the parent nucleus. Target compounds were identified by 1 H NMR, 13 C NMR and/or HR-MS. The results of antifungal activity showed that the antifungal activities of 4d against 6 tested fungi were all more than 60% at 100 μg/mL, and the inhibitory activity of 4d against the 6 tested fungi than the positive control Kresoxim-methyl. SEM test showed that 4d could damage the mycelia of P. piricola. obviously. Moreover, 4d had no effect on cowpea seed germination, showing high safety.