Facile synthesis of porphyrin-conjugates as amphiphilic modified photosensitizer structures of m-THPP bearing carbamate, carboxylate and sulfonate linkers

Abstract

5,10,15,20-Tetrakis(3-hydroxyphenyl)porphyrin (m-THPP) bearing various nitrogen and sulfur containing heterocycles, aromatic, aliphatic and alicyclic residues covalently linked to the oxygen atom of the meta-hydroxy group of the porphyrin unit were synthesized in good yields as potential photosensitizers for photodynamic therapy (PDT). These new amphiphilic conjugates were designed to use three different polar linkers (carboxylate, sulfonate, and carbamate linker units)via the reaction of m-THPP with nicotinoyl chloride hydrochloride (carboxylate linker), 5-bromothiophene-2-sulfonyl chloride (sulfonate linker), phenyl isocyanate, 3,5-bis(trifluoromethyl)phenyl isocyanate, hexyl isocyanate and cyclohexyl isocyanate (carbamate linker). The heterocycles employed are 5- and 6-membered rings with different solubility characteristics