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.
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