Cyclopropylation of Chlorophyllous Degradation Products and Synthesis of Chlorin Derivatives

Pheophorbide-a methyl ester, as a degraded product from chlorophyll-a, was used as a starting material, and the modifications for functional groups along N-21-N-23-axis were completed by making use of reactive regions. The tri-membered ring structures were introduced to the macrocyclic chromophore in different position by 1,3-polar cycloaddition, Grignard reaction and reconstructions for exocyclic ring. A series of unreported chlorins related to chlorophyll were synthesized and their chemical structures were characterized by UV, IR, H-1 NMR, MS techniques and elemental analysis. The different effects on the physical and chemical properties of chlorophyllous chlorins by introduction of cyclopropyl group were discussed and in vitro photodynamic activities of some new compounds were determined.