• azelaic acid;
  • 1,9-nonanedioic acid;
  • systemic acquired resistance;
  • plant signaling;
  • plant hormone

A recent report that the aliphatic dicarboxylic acid, azelaic acid (1,9-nonanedioic acid) but not related acids, suberic acid (1,8-octanedioic acid) or sebacic (1,10-decanedioic acid) acid induces systemic acquired resistance to invading pathogens in plants stimulated the development of a rapid method for labeling these dicarboxylic acids with 11C and 14C for in vivo mechanistic studies in whole plants. 11C-labeling was performed by reaction of ammonium [11C]cyanide with the corresponding bromonitrile precursor followed by hydrolysis with aqueous sodium hydroxide solution. Total synthesis time was 60 min. Median decay-corrected radiochemical yield for [11C]azelaic acid was 40% relative to trapped [11C]cyanide, and specific activity was 15 GBq/µmol. Yields for [11C]suberic and sebacic acids were similar. The 14C-labeled version of azelaic acid was prepared from potassium [14C]cyanide in 45% overall radiochemical yield. Radiolabeling procedures were verified using 13C-labeling coupled with 13C-NMR and liquid chromatography–mass spectrometry analysis. The 11C and 14C-labeled azelaic acid and related dicarboxylic acids are expected to be of value in understanding the mode-of-action, transport, and fate of this putative signaling molecule in plants. Copyright © 2011 John Wiley & Sons, Ltd.