Synthesis, Biological Evaluation, and Docking Study of Ring‐Opening Amide Analogs of Matrine as Antitumor Agents

In this article, we designed and synthesized two series of matrine analogs with ring‐opening in the lactam portion of the molecule. Our in vitro cytotoxicity study showed that analog N ‐(3‐bromophenyl)‐4‐[(1 R ,3a S ,10a R ,10b S )‐decahydro‐1 H ,4 H ‐pyrido[3,2,1‐ ij ][1,6]naphthyridin‐1‐yl]butanamide ( B11 ) with a meta ‐bromide on the phenyl ring displayed the best antiproliferative activity. Moreover, B11 induced cell cycle arrest in G1 phase and cell apoptosis in a dose‐dependent manner in A549 cells. Molecular modeling revealed that B11 achieved a higher docking score compared to its precursor tert ‐butyl (1 R ,3a S ,10a R ,10b S )‐1‐[4‐(3‐bromoanilino)‐4‐oxobutyl]octahydro‐1 H ,4 H ‐pyrido[3,2,1‐ ij ][1,6]naphthyridine‐2(3 H )‐carboxylate ( A11 , an analog of B11 with a Boc group) and parent compound matrine, possibly because B11 formed a hydrogen bond with SER91 and a halogen bond with GLN320 on the binding site of annexin A2. Overall, we discovered the potential anticancer lead compound B11 , which can be used for further study both in vitro and in vivo .