The mixed‐aldehyde synthesis of difunctional tetraarylporphyrins

The synthesis is reported of nine unsymmetrical, meso ‐substituted porphyrins. Among the compounds prepared are the following 5‐( R )‐10,15,20‐tri‐ p ‐tolylporphyrins; R = 2,6‐dinitrophenyl, 4‐hydroxy‐3‐ethoxy‐phenyl, 4‐hydroxy‐3‐methoxy‐5‐nitrophenyl, 5‐hydroxy‐2‐nitrophenyl and 4‐hydroxy‐3‐nitrophenyl. Other porphyrins reported include 5‐(2‐(1‐butoxy)phenyl)‐15‐(2‐nitrophenyl)‐10‐15‐di‐ p ‐tolylporphyrin and the two 5‐( R )‐10‐15,20‐tripropylporphyrins in which R = 2‐nitrophenyl and 2‐hydroxyphenyl. The disubstituted porphyrins offer a rational route to the synthesis of difunctional “tailed‐porphyrins”.