Studies of porphyrin synthesis through 3+1 condensation

초록

Acid-catalyzed porphyrin formation from meso-aryltripyrromethanes and 2,5-bis(α-hydroxy-α-phenyl)methylfuran is studied. The condensation resulted in selective scrambling of tripyrromethanes when the condensation was carried out with catalytic amounts of BF<inf>3</inf> in methylene chloride. But the reaction carried out with pTsOH or BEt<inf>3</inf> catalysts in the presence of NH<inf>4</inf>Cl in acetonitrile, single porphyrin product was isolated without scrambling of starting tripyrromethane. The yields of porphyrin in these studies were somewhat lower than those of 2+2 condensations or aldehyde-pyrrole condensations.