Synthesis of Aureobasidin B Analogs and Their Antifungal Activity Against Candida albicans

Aureobasidins (Abs) are a class of cyclodepsipeptides with interesting antifungal properties but they are difficult to synthesize. This study aimed to synthesize analogs of aureobasidin B (AbB) by a combination of solid- and solution-phase synthesis and to investigate their antifungal properties. The linear peptides were synthesized on 2-chlorotrityl chloride resin with Fmoc strategy and a range of coupling reagents including HATU/HOAt, HBTU/HOBt, and BTC/sym-collidine. The cyclization step was undertaken in the solution phase. Four cyclic nonapeptides (NP1-NP4) and ten cyclic heptapeptides (HP1-HP2, HP4-HP11) were successfully synthesized and characterized. The analogs NP1, NP4, HP1, and HP2 demonstrated moderate antifungal activity against Candida albicans