New Precursors to 3-Sulfanylhexan-1-ol? Investigating the Keto-Enol Tautomerism of 3- S-Glutathionylhexanal

Molecules. 2021 Jul 14;26(14):4261. doi: 10.3390/molecules26144261.


The volatile thiol compound 3-sulfanylhexan-1-ol (3SH) is a key impact odorant of white wines such as Sauvignon Blanc. 3SH is produced during fermentation by metabolism of non-volatile precursors such as 3-S-gluthathionylhexanal (glut-3SH-al). The biogenesis of 3SH is not fully understood, and the role of glut-3SH-al in this pathway is yet to be elucidated. The aldehyde functional group of glut-3SH-al is known to make this compound more reactive than other precursors to 3SH, and we are reporting for the first time that glut-3SH-al can exist in both keto and enol forms in aqueous solutions. At wine typical pH (~3.5), glut-3SH-al exists predominantly as the enol form. The dominance of the enol form over the keto form has implications in terms of potential consumption/conversion of glut-3SH-al by previously unidentified pathways. Therefore, this work will aid in the further elucidation of the role of glut-3SH-al towards 3SH formation in wine, with significant implications for the study and analysis of analogous compounds.

Keywords: 3-sulfanylhexan-1-ol; aroma compound precursors; deuterium exchange; tautomerism; white wine.

MeSH terms

  • Aldehydes / metabolism
  • Fermentation / physiology
  • Hexanols / metabolism
  • Odorants / analysis
  • Sulfhydryl Compounds / metabolism
  • Sulfur Compounds / metabolism*
  • Vitis / metabolism
  • Wine / analysis


  • Aldehydes
  • Hexanols
  • Sulfhydryl Compounds
  • Sulfur Compounds
  • 3-mercaptohexanol