Oxidation of an indole substrate by porphyrin iron(iii) superoxide: relevance to indoleamine and tryptophan 2,3-dioxygenases

Reaction of Fe-III(O-2 & x2d9;(-))(TPP) with 2,3-dimethylindole at -40 degrees C gives the ring-opened, dioxygenated N-(2-acetyl-phenyl)-acetamide product. The reaction was monitored in situ by low-temperature UV-vis and H-1 NMR spectroscopies. This work demonstrates that a discrete iron(iii)(superoxo) porphyrin is competent to carry out indole oxidation, as proposed for the tryptophan and indoleamine 2,3-dioxygenases.