The synthesis of highly fluorescent heterocyclic compounds: Pyrido[2′,1′:2,3]imidazo[4,5-b]quinoline-12-yl cyanides

The syntheses and fluorescence properties of novel derivatives of pyrido[2′,1′:2,3]imidazo[4,5-b]quinoline are described. The key intermediates (4-substituted)(3-hydroxyimino-2,3-dihydroimidazo[1,2-a]pyridin-2-yliden)methyl cyanides were synthesized by reacting the imidazo[1,2-a]pyridine with arylacetonitriles via nucleophilic substitution of hydrogen. The compounds were deep violet in colour. Acylation of hydroxyl group led to heterocyclization and gave highly fluorescent pyrido[2′,1′:2,3]imidazo[4,5-b]quinoline.