This invited paper is part of the Symposium-in-Print: Melanins.
Ultra-low Temperature Oxidation of 5,6-Dihydroxyindole: A Novel Approach to Study Synthetic Melanogenesis†
Article first published online: 14 APR 2008
© 2008 The Authors. Journal Compilation. The American Society of Photobiology
Photochemistry and Photobiology
Volume 84, Issue 3, pages 608–612, May/June 2008
How to Cite
Hatcher, L. Q. and Simon, J. D. (2008), Ultra-low Temperature Oxidation of 5,6-Dihydroxyindole: A Novel Approach to Study Synthetic Melanogenesis. Photochemistry and Photobiology, 84: 608–612. doi: 10.1111/j.1751-1097.2008.00348.x
- Issue published online: 14 APR 2008
- Article first published online: 14 APR 2008
- Received 16 January 2008, accepted 15 February 2008
The detailed structure of melanin remains elusive due to the complexity and insolubility of the pigment. Herein we describe a novel oxidation of 5,6-dihydroxyindole (DHI) as a means to characterize soluble intermediates formed prior to oligomerization. The approach entails the use of a biomimetic copper-peroxo oxidant, at ultra-low temperature (−78°C). DHI oxidized by [LCuII(O2)CuIIL]B(C6F5)4 (L = 2,6,10-trimethyl-2,6,10-triazaundecane) under argon produces the one electron oxidation product, semiquinone radical, which is spectroscopically observed at −78°C. MS analysis of the reaction mixture reveals the DHI dimer as well as other extensively oxidized DHI units.