meso-Substitution products of ætioporphyrin I

Abstract

Schiff's base derivatives have been prepared from meso-aminoætioporphyrin I. The Vilsmeier reaction with ætioporphyrin I leads to the meso-chloro-derivative but with the nickel complex of the porphin the meso-formyl compound is produced which has been characterised as its oxime, hydrazone, and Schiff's bases with aromatic aldehydes. Dehydration of the oxime yields meso-cyanoætioporphyrin I which can be hydrolysed to the meso-carboxy-derivative. The visible and n.m.r. spectra of these derivatives are summarised.