First synthesis of new polycyclic systems from ortho-di(heteroaryl)-substituted furazanopyrazine derivatives by the Scholl reaction

A facile synthetic protocol to hard-to-get polycyclic (hetero)-aromatic compounds annulated to [1,2,4]oxadiazolo[3,4-b]-pyrazine scaffold via the FeCl₃-mediated intramolecular Scholl cross-coupling has been developed. Based on the electrochemical and photophysical measurements, the synthesized polycyclic systems may be regarded as narrow band-gap (from 1.42 to 1.89 eV) n-type organic semiconductors whose energy levels are comparable to those of the commercially available n-type semiconductors