Syntheses of stable bacteriochlorophyll-a derivatives as potential photosensitizers for photodynamic therapy

New methods for conversion of unstable bacteriochlorophyll-a present in Rb. sphaeroides into stable bacteriochlorins are presented. Cyclic imide derivatives from related cyclic isoimide or amide analogs are obtained by intramolecular base catalyzed cyclization. Most of the new bacteriochlorins have long wavelength absorptions in the range of 796-822 nm In preliminary screening, the isoimide analogs have shown promising in vivo photosensitizing activity for the treament of cancer by photodynamic therapy. Copyright (C) 1996 Elsevier Science Ltd