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

Abstract

Reaction of Fe^III(O₂˙⁻)(TPP) with 2,3-dimethylindole at −40 °C gives the ring-opened, dioxygenated N-(2-acetyl-phenyl)-acetamide product. The reaction was monitored in situ by low-temperature UV-vis and ¹H 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.