Discovery of novel Bcr-AblT315I inhibitors with flexible linker. Part 1: Confirmation optimization of phenyl-1H-indazol-3-amine as hinge binding moiety.

As a continuation to our research, a series of novel Bcr-Abl inhibitors incorporated with 6-phenyl-1H-indazol-3-amine as hinge binding moiety (HBM) were developed based on confirmation analysis. Biological results indicated that these compounds exhibited an enhanced inhibition against Bcr-AblWT and Bcr-AblT315I in kinases assays, along with improved anti-proliferative activities in K562 cell assays. In particular, compound Y9 displayed comparable potency with that of imatinib. It potently inhibited Bcr-AblWT and Bcr-AblT315I kinases with IC50 of 0.043 μM and 0.17 μM, respectively. Furthermore, compound Y9 inhibited the proliferation of K562 and K562R cells with IC50 of 1.65 μM and 5.42 μM, respectively. Therefore, 6-phenyl-1H-indazol-3amine as HBM, combined with flexible linker, is a successful strategy contribute to research on T315I mutant resistance, and compound Y9 could be served as a starting point for further optimization.