Design, synthesis, and SAR study of 3-(benzo[d][1,3]dioxol-5-yl)-N-benzylpropanamide as novel potent synergists against fluconazole-resistant Candida albicans

Abstract

Based on our previous discovery and SAR study on the lead compounds 7d, 5 and berberine which can significantly enhance the susceptibility of fluconazole against fluconazole-resistant Candida albicans, a series of 3-(benzo[d][1,3]dioxol-5-yl)-N-(substituted benzyl)propanamides were designed, synthesized, and evaluated for their in vitro synergistic activity in combination with fluconazole. The series 2a–f were designed by replacing the amide moiety of the lead compound 7d with retro-amide moiety, and compounds 2a and 2b showed more activity than the lead 7d. Furthermore, introducing biphenyl moiety into series 2d–f afforded series 3a–r, most of which exhibited significantly superior activity to the series 2d–f. Especially, compound 3e, at a concentration of 1.0µg/ml, can enhance the susceptibility of fluconazole against fluconazole-resistant Candida albicans from 128.0µg/ml to 0.125–0.25µg/ml. A clear SAR of the compounds is discussed.