Synthesis and studies on the photophysical/biophysical properties of triazolylfluorene-labeled 2 '-deoxyuridines

The planar structure, attractive photophysical property, and scarcity of electronically conjugated fluorene-containing biomolecular building blocks have attracted recent research interest on synthesizing triazolylfluorene decorated nucleosides with modulated photophysical features. Herein, we report the synthesis of few fluorescent nucleosides wherein the C5 of 2'-deoxyuridine is electronically conjugated with fluorene analogues via Sonogashira cross-coupling and copper-catalyzed click reaction. The study of photophysical properties of the synthesized nucleosides shows that two of the synthesized nucleosides show interesting dual emission properties in various organic solvents. The dual emitting fluorene nucleosides might impact significantly in nucleic acid research for monitoring the DNA microenvironment. Furthermore, we evaluated the interaction of cyanofluorenyl 2'-deoxyuridine with Calf thymus DNA (ctDNA) and observed that this nucleoside could sense ctDNA via the generation of an enhanced fluorescence signal. (C) 2021 Published by Elsevier Ltd.