The Synthesis of N-Formylmethyl- and N-(2-Hydroxyethyl)- Protoporphyrin IX Dimethyl Esters
Setsune, J.-I. and David Dolphin
J. Org. Chem.
N-(Formylmethyl)protoporphyrin IX di-Me ester zinc chloride and its di-Me acetal were synthesized by the electrochemical reduction of N,Co-(formylmethylene)protoporphyrin IX di-Me ester cobalt(III) chloride. This species, in which the Co and a porphyrin N are bridged by a single C atom, was prepared by the reaction of protoporphyrin IX di-Me ester cobalt(II) with N2CHCHO. N-(2-Hydroxyethyl)protoporphyrin IX di-Me ester zinc chloride was obtained by the reduction of the N-formylmethyl complex with LiAlH(OCMe3)3. The free porphyrins of all of the Zn complexes were obtained by acid-catalyzed demetalation.