Facile synthesis of ortho-pyridyl-substituted corroles and molecular structures of analogous porphyrins

The reactions of 5-(2-pyridyl)dipyrromethane with either pyridine-2-carboxaldehyde or pentafluorobenzaldehyde provided the expected corroles in 22–24% yields when performed according to the protocol perfected for such molecules, while porphyrins were the main products from reactions carried out in hot propionic acid. The ortho-pyridyl-substituted porphyrins were characterized by X-ray crystallography, thus revealing the first molecular structures of such molecules. The new corroles were transformed into water-soluble derivatives via N-alkylation of the pyridyl groups, leading to the first ortho-pyridylium-substituted corroles.