Six methyl pheophorbide-a derivatives were prepared by linking a tryptamine side chain at the C-13 1 , C-15 2 and C-17 3 positions of pheophorbide-a. Prepared conjugates were characterized and evaluated for their photocytotoxicity against A549 cells. The conjugate 6 a with strong absorption at 413 nm (Soret band), 663671 nm (Q bands) and comparable fluorescence quantum yield (0.26) was found to exhibit significant cytotoxicity (659 nM). Molecular integration of pheophorbide-a and tryptamines showed synergistic effects as the most potent conjugate 6 a was identified with enhanced photocytotoxicity when compared to methyl pheophorbide-a. The conjugate 6 a was smoothly taken up by A549 cells and exhibited intracellular localization predominantly to lysosome in the cytoplasm. Upon photoirradiation 6 a generated singlet oxygen to show potent cytotoxicity toward A549 cells.
We have developed an efficient protocol for the synthesis of meso-β-pyrrolo- and indolo[1,2-a]quinoxalino-fusedporphyrin systems 7-9 by PIFA-promoted intramolecular oxidative cyclization of easily accessible meso- pyrrolo- and indolo[1,2-a]quinoxalino-appended porphyrins 6a-j. The...
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