Utilizing scaffold-hopping drug-design strategy, we sought to identify a backup drug candidate for BPR0L075 (1), an indole-based anticancer agent. For this purpose, 5, 6-fused bicyclic heteroaromatic scaffolds were designed and synthesized through shuffling of the nitrogen from the N-1 position or by insertion of one or two nitrogen atoms into the indole core of 1. Among these, 7-azaindole core 12 showed potent in vitro anticancer activity and ...