Divergent Synthesis of Dihydroxanthene-Hemicyanine Fused Near-Infrared Fluorophores through the Late-Stage Amination of a Bifunctional Precursor.

A late-stage amination of a bifunctional dihydroxanthene (DHX) scaffold is reported to access a wide variety of new near-infrared (NIR) chromophores/fluorophores. The divergent approach allows the coupling of aliphatic and aromatic amines and readily provides molecular diversity shedding light on the structure-fluorescence relationship of this emerging class of NIR fluorophores.