Synthesis of functionalized ethynylphenothiazine fluorophores

[GRAPHICS] Alkynylated and butadiynyl-bridged phenothiazines with variable functionalization can be synthesized in good yields by cross coupling and condensation approaches. In addition, the structure of the diethynylated phenothiazine (7a) has been corroborated by an X-ray structure analysis. These oligofunctional heterocycles are fluorescent with modest quantum yields (Phi (f) = 20-35%) and represent suitable building blocks for novel photoexcitable molecular wires.