SYNTHESIS OF 2,7,12,17-TETRAPHENYLPORPHYCENE (TPPO) - FIRST ARYL-SUBSTITUTED PORPHYCENE FOR THE PHOTODYNAMIC THERAPY OF TUMORS

We report on the synthesis of 2,7,12,17-tetraphenylporphycene (TPPo), the first example of an aryl-substituted porphycene macrocycle. A modi fication of the general porphycene synthetic method has been used, thu s avoiding an intermediate sublimation. TPPo has an absorption maximum at 659 nm (epsilon = 50.000 M(-1)cm(-1)), and shows good sensitizing properties: it photoproduces singlet oxygen with a quantum yield of ca . 0.25, is phototoxic to cells, and has low dark toxicity. These prope rties make TPPo a suitable candidate for the photodynamic therapy of t umors.