Syntheses of isomers of protoporphyrin‐IX with permuted propionic side‐chains

Total syntheses of hemins with permutations of the propionic side‐chains in the C and D rings (compared with protoporphyrin‐IX) are described. The products, 3, 2 and 4, are the dimethyl esters of protoporphyrins ‐I, ‐XI, and ‐XIV, respectively. They are of interest in connection with nmr studies designed to elucidate the structural features of the heme crevice in myoglobin and the effect of structural modifications of the C and D rings on the kinetics of heme‐apoprotein reconstitutions, as well as studies of substrate specificity of the heme degradation enzyme, heme oxygenase.