Novel EGFR Tyrosine Kinase Inhibitors Exhibiting Intrinsic Fluorescence

Kinase inhibitors are commonly used in research and clinical practice. Among them, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), such as afatinib and osimertinib, constitute an important subclass. The aim of this study was to create an irreversible covalent EGFR TKI exhibiting endogenous fluorescence, i.e., intrinsic fluorescence without the need for additional fluorochromes. These compounds, designated SQI-2, SLT40, and SLT41, were successfully developed and shown to effectively inhibit the EGFR, EGFRL858R/T790M, and EGFRvIII kinases. The developed compounds are suitable for a range of cytochemical analyses, including real-time assays. The proposed TKIs may serve as research and diagnostic tools and represent precursors of new types of therapeutic compounds.