Synthesis of novel fluorescent styryl dyes based on the imidazo(1,2-a)pyridinium chromophore and their spectral-fluorescent properties in the presence of nucleic acids and proteins

Abstract The imidazo[1,2- a ]pyridinium heterocyclic system was used to prepare styryl dyes. Improved synthetic methods were proposed for the parent imidazo[1,2- a ]pyridines and their corresponding quaternary salts. The standard method for preparing styrylcyanines was modified for the synthesis of the target imidazo[1,2- a ]pyridinium dyes. Spectral-luminescent properties of the obtained dyes in free state and in the presence of nucleic acids, BSA, and BSA/detergent system were studied. 7-[2-(4-Dihexylaminophenyl)-1-ethenyl]-2-(2,4-dimethoxyphenyl)-1-ethylimidazo[1,2- a ]pyridin-1-ium iodide (SIP-8) containing C 6 aliphatic tails and 2,4-methoxy substituents in the 2-phenyl ring exhibited specificity to BSA.