Journal of Lipid Research, Vol. 41, 657-662, April 2000
Copyright © 2000 by Lipid Research, Inc.
Base- and acid-catalyzed interconversions of O-acyl- and N-acyl-ethanolamines: a cautionary note for lipid analyses
S. P. Markeya,
T. Duddinga, and
Tao-Chin L. Wanga
a Laboratory of Neurotoxicology, National Institute of Mental Health, Bethesda, MD 20892-1262
Correspondence to:
S. P. Markey
The isolation and quantification of ethanolamine containing lipids from animal tissues may expose neutral lipid extracts to acidic or basic conditions during chromatographic separations or derivatization chemistry. While investigating the acid- and base-catalyzed production of anandamide in chromatographic fractions of rat brain extracts not containing anandamide, we observed that O,N-acyl migrations are facile. O,N-acyl migrations are well documented in synthetic organic chemistry literature, but are not well described or recognized with regard to methods in lipid isolation or lipid enzyme studies. We report here the synthesis and characterization of O- and N-acyl (palmitoyl- or arachidonoyl-)ethanolamines. Their rearrangements in base and acid are quantified by liquid chromatography;electrospray ionization mass spectrometry. The rearrangements proceed through a cyclic intermediate that is also formed during chemical reactions commonly used for derivatization of acylethanolamines for gas chromatographymass spectrometry.
The isolation and characterization of N- or O-acylethanolamines and their enzymatic formation requires awareness and consideration of the proclivity of these compounds to chemically rearrange.Markey, S. P., T. Dudding, and T-C. L. Wang. Base- and acid-catalyzed interconversions of O-acyl- and N-acyl-ethanolamines: a cautionary note for lipid analyses. J. Lipid Res. 2000. 41: 657;662.
Supplementary key words:
anandamide, arachidonoylethanolamide, palmitoylethanolamide, mass spectrometry