Photo- and electrochemical properties of novel 7-substituted naphthyridine derivatives

Here we report a new class of 1,8-naphthyridine derivatives, 2-amino-7-(3,4-dimethoxyphenyl)-1,8-naphthyridine, 2-amino-7-(3,4-dihydroxy phenyl)-1,8-naphthyridine, 2-amino-(5,6-dimethoxy-1 H-indenyl [2,3-b])-1,8-naphthyridine, and 2-amino-(5,6-dihydroxy-1 H-indenyl [2,3-b])-1,8- naphthyridine. All of these compounds were synthesized via naphthyridine-ring forming reaction with 2,6-diaminopyridine-3-carboxaldehyde as a key step. The two dimethoxy derivatives showed predominant fluorescent emission around 400 nm in MeCN. Cyclic voltammetry of the two dihydroxy derivatives in phosphate buffer showed oxidation potentials of 0.2~0.25 V vs. Ag/AgCl.