The first 5,6-dihydroxyindole tetramer by oxidation of 5,5',6,6'-tetrahydroxy- 2,4'-biindolyl and an unexpected issue of positional reactivity en route to eumelanin-related polymers

Org Lett. 2007 Mar 29;9(7):1411-4. doi: 10.1021/ol070268w. Epub 2007 Mar 9.

Abstract

[structure: see text]. The first tetramer of the eumelanin precursor 5,6-dihydroxyindole has been obtained, as the acetyl derivative, by peroxidase/H2O2-induced oxidative coupling of 5,5',6,6'-tetrahydroxy-2,4'-biindolyl (2) in the presence of Zn2+ ions. The tetramer, 5,5',5'',5''',6,6',6'',6'''-octaacetoxy-2,4':2',3'':2'',4'''-tetraindolyl (acetylated 7), incorporates an unprecedented 2,3'-biindolyl substructure suggestive of a different positional reactivity of the 5,6-dihydroxyindole system when framed into a dimeric scaffold.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Indoles / chemical synthesis*
  • Indoles / chemistry*
  • Melanins / chemistry*
  • Molecular Structure
  • Oxidation-Reduction
  • Polymers / chemical synthesis*
  • Polymers / chemistry

Substances

  • 5,5',6,6'-tetrahydroxy-2,4'-biindolyl
  • Indoles
  • Melanins
  • Polymers
  • eumelanin
  • 5,6-dihydroxyindole