Regioselective syntheses of ether-linked porphyrin dimers and trimers related to photofrin-II®

Using isomerically pure 4-(1-hydroxyethyl)deuteroporphyrin-IX dimethyl ester 10, 2-(1-hydroxyethyl)deuteroporphyrin-IX dimethyl ester 11, 2-acetyl-4-(1-hydroxyethyl)deuteroporphyrin-IX dimethyl ester 12 and 4-acetyl-2-(1-hydroxyethyl)deuteroporphyrin-IX dimethyl ester 13 as starting materials, a series of regiochemically pure ether-linked porphyrin dimers 25-41 and trimers 42-47 related to an anticancer drug known as Photofrin-II® were synthesized. Proton NMR nuclear Overhauser enhancement experiments and variable temperature proton NMR spectroscopy were used to characterize the isomers. Some of these compounds were tested for their in vivo photosensitizing ability vis-a-vis Photofrin-II® and the preliminary results are briefly described.