Synthesis of potential antitumor agents, dimeric and trimeric chlorins, from methylpheophorbide a

Abstract

A series of dimeric and trimeric chlorins were synthesized from methylpheophorbide a. They are potential photosensitizers for photodynamic therapy in oncology. The macrocycles were conjugated due to the formation of ester and amide bonds. The carboxy groups were activated and catalytic transesterification was carried out to form the ester bond. The amide bond was formed using carboxy group activation; in several cases, amidation of the ester group in position 13(2) of the exocycle of methylpheophorbide α was carried out, which does not require activation.