Visible-Light-Active Coumarin- and Quinolinone-Based Photocatalysts and Their Applications in Chemical Transformations

Organic dyes have been actively studied as useful photocatalysts because they allow access to versatile structural flexibility and green synthetic applications. The identification of a new class of robust organic chromophores is, therefore, in high demand to increase structural diversity and variability. Although coumarins and quinolinones have long been acknowledged as organic chromophores, their ability to participate in photoinduced transformations is somewhat less familiar. Fascinated by their chromophoric features and adaptable platform, our group is interested in the identification of fluorescent bioactive molecules and in the development of new photoinduced synthetic methods using coumarins and quinolinones as photocatalysts. This account provides an overview of our recent progress in the discovery and application of light-absorbing coumarin and quinolinone derivatives in photochemistry and medicinal chemistry.     

Synthesis and Biological Evaluation of Quinolinone Compounds as SARS CoV 3CL^pro Inhibitors

SARS CoV 3CL^pro is known to be a promising target for development of therapeutic agents against the severe acute respiratory syndrome （SARS）. A quinolinone compound 1 was selected via virtual screening, and it was syn- thetized and tested for enzymatic inhibition in vitro. Compound 1 showed potent inhibitory activity （ICs0= 0.44 μmol/L） toward SARS CoV 3CL^pro. Further work on a series of quinolinone derivatives resulted in the discovery of the most potent compound 23, inhibiting SARS CoV 3CL^pro with an IC50 of 36.86 μmol/L. The structure-activity relationships were also discussed.