Synthetic Access to Tetracationic Benzoporphyrins and Their Role as Photosensitizers towards Gram-Negative <i>Escherichia coli</i> 

Abstract

Currently, world population faces an episode where bacteria are becoming resistant to antibiotics, and it is crucial to find alternatives and new molecules to fight these microorganisms. Photodynamic inactivation of microorganisms has been pointed out as an alternative to conventional therapies. This work describes the synthesis of benzoporphyrins derivatives bearing triazolyl groups and of the analogues with pyridyl units under Heck coupling conditions. The benzoporphyrin derivatives containing pyridyl groups were further quaternized with iodomethane and 1-iodopentane to evaluate the influence of alkyl chain size on their photoinactivation ability. The biological studies towards Gram-negative Escherichia coli showed that the tetracationic benzoporphyrins can efficiently inactivate this bacterium.

Keywords

• tetracationic benzoporphyrins
• Heck coupling reaction
• antimicrobial photodynamic therapy
• bioluminescent <i>E. coli</i>