Michaela Kotaskova, Okan Osman Oglou and Mark Helm
Org. Biomol. Chem., 2014,12, 3816-3820
DOI:
10.1039/C4OB00533C,
Communication
Addition of a single functional handle to the tricyclic moiety of fluorescein results in asymmetric xanthene dyes. Our synthesis of a new class of asymmetric xanthenes proceeds via an unusual SNAr with sulfur nucleophiles on electron rich aromatic xanthenes scaffolds in the absence of a metal catalyst. The resulting 3′-thioethers exhibit high photostability and are conveniently converted into reactive dyes for macromolecule labelling.