Synthesis of photostable amine-reactive fluorescent dyes by postsynthetic conversion of bromide dithienothiophene derivatives.

The synthesis, purification, and spectral properties of new dithienothiophene-based fluorescent dyes with a terminal alkyl bromide group are described. The bromides were easily converted to isothiocyanates and N-succinimidyl esters by appropriate chemical transformations with sodium thiocyanate or N-hydroxysuccinimide. The new fluorophores exhibited intense fluorescence emission and high photostability. Their suitability for bioanalytical applications was evaluated through conjugation with amine-reactive polystyrene microspheres and IgG anti-CD3 monoclonal antibody.