Open AccessPhotosensitizers for photodynamic therapy: One-pot heterogeneous catalytic transfer reduction of porphyrins
Author(s) -
A. F. Brigas,
Ana M. Rosa da Costa,
Arménio C. Serra,
Catarina Pires
Publication year - 2011
Publication title -
journal of pharmacy and bioallied sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.268
H-Index - 36
eISSN - 0976-4879
pISSN - 0975-7406
DOI - 10.4103/0975-7406.80770
Subject(s) - catalysis , photochemistry , chemistry , porphyrin , tetrahydrofuran , photodynamic therapy , tetraphenylporphyrin , solvent , formic acid , toluene , photosensitizer , combinatorial chemistry , organic chemistry
A number of new porphyrin-based photosensitizers have been developed for Photodynamic Therapy (PDT) in recent years. Chlorins, which are a reduced form of porphyrins, show better potential of application since they have a stronger absorption band on the red region of the visible spectrum and, hence, a deeper penetration into tissues. We found that by using heterogeneous catalytic transfer reduction (CTR), meso-tetraphenylporphyrin (TPP) could be hydrogenated, although in modest yields, to meso-tetraphenylchlorin (TPC) in a single reaction step. Best reaction conditions were attained using formic acid or sodium phosphinate/water as hydrogen donors, tetrahydrofuran (THF) or toluene as solvent and 10% palladium on charcoal as catalyst.