Synthesis of fluorescent 1,3-diarylated imidazo[1,5-a]pyridines: oxidative condensation-cyclization of aryl-2-pyridylmethylamines and aldehydes with elemental sulfur as an oxidant.
Oxidative condensation-cyclization of aldehydes and aryl-2-pyridylmethylamines proceeded in the presence of a stoichiometric amount of elemental sulfur as an oxidant in the absence of catalyst. The reaction gave a variety of 1,3-diarylated imidazo[1,5-a]pyridines in good to high yields. The products showed fluorescence emission in a wavelength range of 454-524 nm. The quantum yields of 1,3-diarylated imidazopyridines were greatly improved compared to those of the parent 3-monosubstituted compounds.
Shibahara
Fumitoshi
F
Department of Chemistry, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan. fshiba@gifu-u.ac.jp
Sugiura
Rie
R
Yamaguchi
Eiji
E
Kitagawa
Asumi
A
Murai
Toshiaki
T