First Synthesis of Azachlorins and Azacorrins with a N-Atom in β-Pyrrolic Positions

Azachlorins 7 and 11, and azahexadehydrocorrin rac‐10 are novel structural types of tetrapyrrolic macrocycles. Synthesis of the target structures bearing N‐atoms in the β‐periphery of the macrotetracycles could be achieved by attaching an imidazole moiety 4 to the tricyclic Ni complex rac‐5, followed by cyclization. Depending on the central metal ion of the bilin intermediates rac‐6a and rac‐6b, chlorin‐ or corrin‐type structures were formed by cyclization.