Porphyrins, Chlorins and Phthalocyanines

Localization and photodynamic efficiency of a mono-cationic porphyrin (MCP) 453 from 452 were assessed by Kessel and coworkers. The therapeutic response to MCP appeared to be related mainly to vascular effects. 

Michelsen et al. reported a new class of cationic photosensitizers 466 for PDT. These unsymmetrical substituted benzonaphthoporphyrazines are synthesized to have one to eight positive charges. The Q-band transition exhibits a red shift from 680 to 760 nm dependent upon the number of annealed naphthalene rings. The singlet-oxygen yields of these compounds are normally higher compared with zinc phthalocyanine. 

Another interesting approach reported by Driaf et al. involves the synthesis of glycosylated cationic porphyrins 

467-471. The rationale was that 0-glycosylation of the cationic porphyrins may increase cell-membrane interactions, and the various lipophilic substituents will allow for increased penetrability of porphyrins across the cell membrane. 

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