A General Synthesis of Bis(o-azaheteroaryl)methane Derivatives from N-Oxides of Azines and Azoles

A general method of preparation of derivatives of bis(o-azaheteroaryl)methanes from aromatic N-oxides is reported, the key step of which is a 1,3-dipolar cycloaddition between N-oxides of azines or azoles and in situ generated terminal difluoroalkenes containing an o-azaheteroaryl substituent at the double bond. Selected products were applied for the preparation of two novel unsymmetrical analogues of BODIPY fluorescent dyes, containing both an imidazole and a quinoline or isoquinoline unit.