Dimerization of Pheophorbide а with Activated Carboxylic Group in the Reaction with Ethylenediamine

Abstract

The interaction of ethylenediamine with pheophorbide a, carboxylic group of the latter being activated with di-tert-butyl dicarbonate, has been studied. Acylation of two amino groups of ethylenediamine with activated pheophorbide a and the formation of phorbine-phorbine dimer with the macrocycles bound in the dimer via amide bonding with ethylenediamine bridge have been demonstrated. It has also be found that the phorbine-phorbine dimer is formed even in large excess of ethylenediamine with respect to pheophorbide a.