Study of the Position of the Conjugated Substitute Influence on the Optical Properties of the Kaede Protein Chromophore Derivatives

— We report novel derivatives of a chromophore of the fluorescent protein Kaede, ( Z )-2-(4-methoxybenzylidene)-6/8-phenylimidazo[1,2- a ]pyridine-3(2 H )-ones. The introduction of phenyl substituent in the 6- and 8-position of the imidazopyridinone fragment does not lead to a shift in absorption and emission spectra.