Synthesis and Structure-Activity Relationships of Novel Neocryptolepine Derivatives

Herein we reported the synthesis of a novel series of neocryptolepine（5-methyl-5H-indolo[2,3-b]quinoline） derivatives containing different substituents at Cll using methyl 1H-indole-3-carboxylate and N-methylaniline as starting material. The target 21 compounds were evaluated for their axltibacterial activity in vitro against gram-positive bacteria（B, subtilis and S. aureus） and gram-negative bacteria（E, coli and S.typhi）. Almost all the tested compounds showed moderate to high activities against the four bacterial strains at the minimum inhibitory concentrations（MICs） of 1-10μg/mL. The obtained results suggest that part of the novel synthetic neocryptolepine derivatives exhibit significant antibacterial effect against all the tested organisms.