Discovery of Substituted 1H‑Pyrazolo[3,4‑b]pyridine Derivatives as Potent and Selective FGFR Kinase Inhibitors

Fibroblast growth factor receptors (FGFRs) are important targets for cancer therapy. Herein, we describe the design, synthesis, and biological evaluation of a novel series of 1H-pyrazolo­[3,4-b]­pyridine derivatives as potent and selective FGFR kinase inhibitors. On the basis of its excellent in vitro potency and favorable pharmacokinetic properties, compound 7n was selected for in vivo evaluation and showed significant antitumor activity in a FGFR1-driven H1581 xenograft model. These results indicated that 7n would be a promising candidate for further drug development.