Synthesis, DNA Photocleavage and Singlet Oxygen Measurement of Cationic Bisporphyrins

Abstract

ABSTRACT. With −OCH2CO− as a linker, a non β-substituted cationic bisporphyrin (4a) and a β-substituted cationic bisporphyrin (4b) were prepared through methylation of the intermediate which was obtained from β-amino-5,10,15,20-tetra (4-cyanophenyl) porphyrin or 5-hydroxylphenyl-10,15,20-tris(4-cyanophenyl) reacting with 5-hydroxy-10,15,20-trispyridinylporphyrin. Their structures were confirmed by 1 H NMR, IR, UV-vis, MS and elemental analysis. DNA photocleavage ability and the singlet oxygen ability of those cationic bisporphyrins were investigated. DNA photocleavage activity of β-substituted cationic bisporphyrin was significantly weaker than that of H2TMPyP, but similar to that of non β-substituted cationic bisporphyrin. While 4a and 4b showed substantial photocleavage activities toward DNA, with 68% and 66% observed at 10 µM. The assessment of indirectly measured 1 O2 production rates against H2TMPyP were described and the relative singlet oxygen production yields were: free cationic bisporphyrins > H2TMPyP. The results showed the cationic bisporphyrins with β-substitution and non β-substitution could be developed as potential photodynamic agents.

On the synthesis of functionalized porphyrins and porphyrin conjugates via β-aminoporphyrins

“…A commonly used acylation reaction (Scheme 1, Path A) does not tolerate many functional groups at the meso-aryl substituents because acyl halides are highly reactive towards nucleophilic substitution. [37][38][39][40][41] In addition, a flexible character of the alkylamide spacer could be somewhat inconvenient in part because of undesirable intramolecular interactions of the functional groups with the central metal ion of the porphyrin complex.…”