Revisiting 2,3-diaminoporphyrins: key synthons for heterocycle-appended porphyrins

Abstract A general strategy for the preparation of functionalized imidazole- and pyrazine-appended porphyrins involving in situ generation of 2,3-diaminoporphyrin and its subsequent interaction with carbonyl compounds was developed. The tuning of the selectivity of the reaction between 2,3-diaminoporphyrin and aromatic aldehyde by variation of the reaction conditions was demonstrated. Efficient pathways are revealed allowing selective preparation of different types of heterocycle-appended porphyrins, namely arenepyrazino-, 2-arylimidazo- and 2,3-diarylpyrazino-derivatives.