A practical synthesis of meso-monosubstituted, β-unsubstituted porphyrins

graphic A simple straightforward synthesis for meso-monosubstituted, beta-unsubstituted porphyrins is reported. Porphyrins of this type are easily prepared by condensation of dipyrromethane, pyrrole-2-carbaldehyde, and the desired aromatic or aliphatic aldehyde. The method can be used for a variety of functional groups with yields between 2 and 12%. In most cases, the 5,15-disubstituted porphyrin is obtained as a second product but can be removed easily.