Microwave-assisted synthesis of base modified Furo[3,2-c]quinolone nucleosides and insights into their photophysical properties

A green, catalyst free, one-pot, gram scale microwave-assisted synthesis of fluorescent furo [3,2- c ]quinolone nucleoside analogues has been successfully developed using 2-Me-THF as a greener solvent . This method, employing 3′,5′-di- O -acetyl-5-formyl-2′-deoxyuridine, alkyl isocyanides , and differently substituted 4-hydroxyquinolones, achieved product yield up to 92 %, which offers high atom economy, reduced reaction time and simple work-up procedure. The products were fully characterized by spectroscopic techniques and single crystal X-ray analysis with DFT analysis conforming the electronic structures. Fluorescence studies revealed strong emission (∼450 nm), large Stokes shifts (59–98 nm), and high quantum yields (0.053–0.595). Solvatochromism studies highlighted their environmental sensitivity, indicating potential applications in nucleic acid research and bio-imaging. • Synthesized fluorescent furo [3,2- c ]quinolone nucleoside analogues . • Exploration of the electronic structure of the synthesized nucleosides via DFT analysis. • Photophysical studies showed high fluorescence, Stokes shift, and quantum yield. • Scalability demonstrated by gram-scale production of one of the compounds.