Synthesis of a new class of strongly fluorescent heterocyclic compounds: 3H-imidazo[4,5-a]acridine-11-carbonitriles

The synthesis, spectral characterization and fluorescence studies of some novel substituted 8-chloro-3H-imidazo[4,5-a]acridine-11-carbonitriles are presented. The nucleophilic substitution of hydrogen in 5-nitrobenzimidazole derivatives occurs upon reaction with 2-(4-chlorophenyl) acetonitrile under basic conditions and proceeds with concomitant cyclisation. This sequence offers a one-pot synthesis of new fluorescent heterocyclic compounds, 8-chloro-3-alkyl-3H-imidazo[4,5-a]acridine-11-carbonitriles. The fluorescence of all compounds was intense and fluorescence quantum yields were very high (>0.85) for all of them.