Frontiers in the electrophilic nitration of meso-tetraphenylporphyrin derivatives

Abstract

The electrophilic nitration of 5,10,15,20-tetraphenylporphyrin derivatives bearing electron-withdrawing groups on meso-phenyl rings is described. The reaction with yellow fuming nitric acid (d = 1.52) in CHCl₃, contrary to the previous observations, took place at the β-position. This mode of reactivity for free-base porphyrins has never been described earlier in the literature.