The chemistry of pyrrolic compounds. XVI. β-Electronegatively substituted dipyrrylmethines

Abstract

The chemistry of dipyrrylmethines bearing β-electronegative substituents is reported. The presence of these electrophilic groups makes the preparation of α-bromomethyl derivatives difficult and this imposes certain limitations on the type of porphyrin which can be prepared by way of these intermediates. Acetyl groups located in the 3- position readily cyclize with one of the pyrrolic nitrogen atoms to give the tricyclic pyrroloindolizine system.