Concise Synthesis and Biological Evaluation of a Phorbazole Analogue-B1 Identifies a Multi-Kinase Inhibitor with Anti-AML Activity.

Phorbazoles are bioactive marine alkaloids whose development is hampered by limited supply. We report a concise synthesis of the deschloro-phorbazole core via an optimized iodine-catalyzed oxazole annulation (56% yield). This route enabled efficient access to the scaffold and the preparation of analog B1. B1 showed nanomolar cytotoxicity (IC50 = 0.04 µM) against MV4-11 leukemia cells by inducing G0/G1 arrest (via cyclin D1/CDK6 downregulation) and apoptosis. As a multi-kinase inhibitor, B1 also potently inhibited endothelial network formation and migration, demonstrating anti-angiogenic activity. This work provides an efficient synthetic strategy and identifies B1 as a promising dual-function anticancer lead compound.