A Convenient Procedure for Moderate-scale Rothemund Synthesis of Lipophilic Porphyrins: an Alternative to the Adler–Longo and Lindsey Methodologies

Rothemund synthesis of porphyrins is conveniently achieved using p-toluenesulfonic acid-catalysed reaction between pyrrole and aldehyde with azeotropic removal of the water formed in the reaction. These conditions are suitable for moderate-scale reactions and involve an easy work-up. In this way, 5,10,15,20-tetraheptylporphyrin (2), 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrin (3), 5,10,15,20-tetra-tert-butylporphyrin (4) and 5,10,15,20-[pyromellitoyl(tetrakis-o-oxyethoxyphenyl)]por-phyrin (5) were prepared in moderate to good yields.