π-Expanded azaullazines: synthesis of quinolino-azaullazines by Povarov reaction and cycloisomerisation

Org Biomol Chem. 2024 Mar 6;22(10):2027-2042. doi: 10.1039/d4ob00091a.

Abstract

Doping and extension of polycyclic aromatic hydrocarbons (PAHs) by simple and efficient synthetic methods is of increased demand for the development of novel and improved organic electronics. Diarylindolizino[6,5,4,3-ija]quinolino[2,3-c][1,6]naphthyridines (quinolino-azaullazines) were prepared by combination of Pd catalyzed cross-coupling with Povarov and cycloisomerisation reactions. The products contain an electron-rich ullazine and an electron-poor quinoline moiety and show intramolecular charge transfer properties that can be tuned by the substitution pattern. The optical properties were studied experimentally and further elaborated by (TD)DFT calculations.