Synthetic access to 5,10-disubstituted porphyrins

A simple acid-catalyzed condensation of unsubstituted tripyrranes with pyrrole and various aldehydes affords 5,10-disubstituted-β-unsubstituted porphyrins by the ‘3+1’ approach in low to moderate yields. A complementary synthesis of similar compounds involves reaction of unsubstituted porphyrin (porphine) with organolithium reagents in good yields.