In this work, we studied the interaction of methylpheophorbide a with 1,3-diaminopropane and proposed a simple method for the synthesis of chlorin e6 derivatives with one, two, and three amino groups on the periphery of the macrocycle. It is shown that, when methylpheophorbide a acts on 1,3-diaminopropane in a medium of chloroform or methylene chloride, the exocycle opens chemically selectively and chlorin e6 13-amide derivative of with an amino group attached by a spacer of three methylene groups forms (chlorin e6 13-N-(3-aminopropyl)amide 15,17-dimethyl ether). By the action of 1,3-diaminopropane on chlorin e6 13-N-(3-aminopropyl)amide 15,17-dimethyl ether at room temperature without solvent, chlorin e6 13,17-N,N'-(3-aminopropyl) can be chemically selective diamide 15-methyl ether and chlorin e6 13,17-N,N',N''-(3-aminopropyl)triamide with two and three amino groups, respectively. The preparation of di- and triaminochlorins can be carried out both from chlorin e6 13-N-(3-aminopropyl)amide of 15,17-dimethyl ether, and directly from methylpheophorbide a without isolation of the intermediate monoaminochlorin. In the latter case, after the methylpheophorbide a exocycle is opened with 1,3-diaminopropane in chloroform or methylene chloride medium, the solvent is distilled off from the reaction mixture and the resulting monoaminochlorin reacts with the 1,3-diaminopropane present in the mixture without solvent. The structure of the obtained mono-, di, and triaminochlorins is confirmed by IR and NMR spectroscopy.
