Synthesis of amide derivatives of chlorin e6 and investigation of their biological activity

In this work there is a synthesis of new photosensitizers which is based on amide derivatives of chlorin е6 . For the disclosure of an extra ring of the initial compound - pheophorbide a 1, we used primary aliphatic amines with 4-12 carbon atoms in the alkyl chain. The reaction is carried out under mild conditions in chloroform with heating to 40 ºС. The structure of all compounds obtained was confirmed by means of electronic, IR, 1Н-NMR spectroscopy and mass-spectrometry. The photoactivity and the dark toxicity of the compounds 2b-2h were investigated on two cancer cell lines: P-388 and K-562. The biological investigations revealed a good photoactivity and low dark toxicity of all compounds 2b-2f. The amide derivatives of chlorin е6 with 6 and 7 carbon atoms in the alkyl part showed the best results in our research. Thus, in this paper we propose a reliable scheme of synthesis of chlorin's photosensitizers which are promising agents for PDT.