SYNTHESIS OF NEW 5-ATOM-LINKED CAPPED PORPHYRINS

The synthesis and characterization of three new five-atom-linked ''cap ped'' porphyrins, 6, 12, and 18, are reported. The general synthetic p rocedure involves synthesis of a tetraaldehyde ''cap'' by reacting the five-atom ''arm'' with 1,2,4,5-tetrahydroxybenzene in DMSO solvent in the presence of KOH. The tetraaldehyde and pyrrole are reacted to for m the capped porphyrin. These compounds are useful as models for the a ctive sites of heme proteins.