Ligand-free palladium-catalyzed facile construction of tetra cyclic dibenzo[b,h][1,6] naphthyridine derivatives: domino sequence of intramolecular C-H bond arylation and oxidation reactions

A ligand-free Pd-catalyzed approach has been developed for the synthesis of dibenzo-fused naphthyridines. The reaction involves a one-pot domino sequence of reactions involving C-H functionalisation and oxidation. The reaction was applicable to a wide range of substrates, giving the required product. Further fluorescence studies were performed where the Stoke's shift was found to be dependent on the polarity of the solvent.