Coupling of L-histidine methyl ester and L-histidine-containing peptide esters to ferric protoporphyrin IX chloride

Abstract

The coupling of L-histidine methyl ester and L-histidine-containing peptide esters to ferric protoporphyrin IX chloride is performed by the mixed carboxylic–carbonic acid anhydride method to give the disubstituted products in good yield: spectroscopic evidence indicates that the degree of interaction between the imidazole ligands and the iron atom depends upon the length of the peptide chain.