A mechanistic study of the synthesis of <i>meso</i>‐tetraphenylporphin

Abstract In continuation of an earlier preliminary study, some further physical and synthetic studies on the homogenous phase condensation of pyrrole and benzaldehyde to ms ‐tetraphenylporphin in acidic media were undertaken. The role of atmospheric oxygen in the reaction was studied in some detail. The effects of acidity, solvent, concentration, and other constraints on both the rate and yield of the reaction were also investigated. Details of the mechanism, including possible intermediate structures, have been clarified and a reaction scheme accounting for the data is presented.