Fused porphyrin-imidazole systems: new building blocks for synthesis of porphyrin arrays

Reaction of porphyrin-2,3-diones with aromatic aldehydes and NH4OAc in AcOH–CHCl3 affords 2-aryl-1H-imidazo[4,5-b]porphyrins which, with appropriate substitution, are useful building blocks for the synthesis of multi-porphyrin arrays; porphyrin-tetraones are similarly converted into the corresponding bis-fused systems.