Chlorin-type photosensitizers derived from vinyl porphyrins

The reaction of singlet oxygen with vinyl porphyrins, which was first described in the case of protoporphyrin, is reinvestigated as a route to chlorin type molecules. Various dicarboxylic chlorins were thus prepared and characterized for their chemical and photosensitizing properties. All of them efficiently photosensitize the production of singlet oxygen. Some of these compounds might be formed during photodynamic therapy with hematoporphyrin derivative or Photofrin. Their biological relevance is discussed.