No abstract

A series of formyl analogs of chlorin e 6 13-amides were synthesized in high yields by reaction under mild conditions of primary and secondary amines with methylpheophorides b and d. In contrast with the secondary 13-amides, tertiary 13-amides were found as two isomers differing in the orientation of the amide plane relative to the plane of the chlorin ring. Methylpheophorbides b and d were more reactive toward the amines than methylpheophorbide a.Keywords: methylpheophorbides b and d, amides, rhodin g 7 13-amides, formyl analogs of chlorin e 6 13-amides, atropoisomerism.Porphyrins are a promising platform for synthesizing antitumor drugs with various mechanisms of action [1-3]. Because the chlorin molecule contains an aldehyde and the possibilities of its further chemical transformations are greatly expanded by the additional reaction center, it seemed interesting to study chemical transformations of chlorophylls b and d and their derivatives.The known method for synthesizing chlorin e 6 13-amides consists of the reaction of methylpheophorbide a (1) with primary and secondary amines [4][5][6][7]. We used the reaction of primary and secondary amines with formyl analogs of 1, methylpheophorbides b (2) and d (3), in order to synthesize previously unreported formyl analogs of chlorin e 6 amides.

No abstract

The concentrations, at which chlorin-myrtenic (3) and chlorin-camphenylanic (4) conjugates exhibit photoinduced cytotoxicity, differ by more than two orders of magnitude from the concentrations at which these compounds show dark cytotoxicity. In comparison, the difference between the active concentrations under the light and in-the-dark for Photolon is approximately one order of magnitude. This allows to suggest a high potential of the new compounds 3 and 4 for further in vitro and in vivo studies to eventually improve the efficiency and safety of photodynamic therapy of cancer.Keywords: Chlorin e 6 , terpene acids, chlorin-terpene conjugates, dicyclohexylcarbodiimide (DCC), photosensitizers.Новые хлорин -терпеновые конъюгаты: синтез, фотоиндуцированная и темновая цитотоксичность

No abstract

No 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 а was carried out, which does not require activation.

A series of chlorins containing a vinyl group on the periphery of the chlorin ring that was attached by linkers of various length, potential monomers for synthesis of polymers containing chlorin via copolymerization, was synthesized from methylpheophorbide a.Key words: methylpheophorbide a, chlorin e 6 , chlorins with a distal vinyl group, monomers for copolymerization.Porphyrins and their analogs grafted to polymers are promising photosensitizers for photodynamic sterilization of donor blood [1]. In particular, the synthesis of polymers with natural chlorins, especially the most abundant chlorophyll a and its derivatives, are of great interest. These compounds are attractive for synthesizing photosensitizers because, on one hand, they have good spectral properties and low toxicity [2] and, on the other, they have many reactive centers that enable various chemical transformations to be performed [3]. The vinyl group intrinsic to chlorophyll a and its derivatives can be used for copolymerization only with difficulty because it is bonded directly to the chlorin macrocycle and significant steric hindrances arise if it is used for the polymerization. A vinyl group distant from the macrocycle must be introduced into natural chlorin so that it can be used in copolymerization. Thus, the development of a method for synthesizing chlorins with a distal vinyl group is of great interest.Chlorophyll a itself is rarely used as starting material for chemical transformations because of its poor stability and difficulties with preparing it pure.Herein methylpheophorbide a (1), which is much more stable than chlorophyll a and is readily prepared pure while at the same time has the same reactive centers as chlorophyll a, is used as starting material for synthesizing chlorins with a vinyl group distant from the macrocycle. An allyl moiety was introduced on the periphery of the chlorin ring (4, 5, 7) by reactions at the exocycle and the 17-ester of 1. Chemical transformations were used both for introducing the vinyl group on the periphery of the chlorin ring and for introducing a reactive center distant from the macrocycle.The exocycle of chlorophyll a and its analogs, which have the same substituents in them, can be opened by primary and secondary amines [3]. This forms an amide bond at the 13-position. Substituents on the amine N atom end up bonded to the chlorin macrocycle. This reaction was used to synthesize from 1 chlorin e 6 13-amides with substituents of various hydrophilicity on the amide N atom [4,5].We synthesized chlorin e 6 13-amide (5), in which the vinyl group is bonded to the chlorin macrocycle by a 3-atom linker, by reacting 1 and allylamine. The action of certain amines on 1 is known to open the exocycle and convert the ester to an amide [5]. In this instance, this process would have been undesirable because introducing more than one distal vinyl group into chlorin could lead to formation of cross-linked polymers. The presence in the PMR spectrum of the main reaction product of singlets for the methyls of both ester...