Fibroblast growth factor receptors (FGFRs) are frequently dysregulated in diverse cancers and represent important therapeutic targets. Here, we describe the design and synthesis of nucleoside-based irreversible pan-FGFR inhibitors. Structure-activity ...
Fibroblast growth factor receptors (FGFRs) are frequently dysregulated in diverse cancers and represent important therapeutic targets. Here, we describe the design and synthesis of nucleoside-based irreversible pan-FGFR inhibitors. Structure-activity relationship studies, supported by X-ray co-crystal structure and molecular dynamics simulations analysis, identified the fused aromatic substituents and 4'-thio ribose enhanced FGFR potency, while enantiomeric inversion of ribose compromised activities. Thus, 7-methoxy-5-methylbenzo[b]thiophene scaffold and ribose moiety were identified as critical determinants of potency and selectivity. Representative compounds, such as 13f, 19e, and 22f demonstrated potent FGFR1–4 inhibition and dose-dependent suppression of FGFR1-mediated signaling. These compounds exhibited strong antiproliferative activity in both FGFR-driven and wild-type cancer models. Compound 22f showed efficient irreversible FGFR engagement and improved metabolic stability, with covalent binding to the conserved cysteine residue confirmed at the protein and cellular levels. Overall, these results establish nucleoside analogues as a privileged scaffold for covalent pan-FGFR inhibition.