9-Fluorenylmethoxycarbonyl (Fmoc)-glycine coupling of saccharide beta-glycosylamines for the fractionation of oligosaccharides and the formation of neoglycoconjugates

Anal Biochem. 1994 Jan;216(1):165-70. doi: 10.1006/abio.1994.1021.

Abstract

We have devised a new saccharide derivatization scheme to provide not only the temporary attachment of a chromophore for detecting and facilitating the chromatographic separation of carbohydrates, but also the intermediates for further derivatization to produce neoglycoconjugates. Several neutral unprotected saccharide beta-glycosylamines were formed by the direct condensation of the reducing saccharides with aqueous ammonium bicarbonate. The beta-glycosylamine derivatives of N-acetylglucosamine, di-N-acetylchitobiose, and asialo-, digalactosylated biantennary complex oligosaccharide were N-acylated separately with excess 9-fluorenylmethoxycarbonyl (Fmoc)-glycine. The Fmoc-glycinamido beta-derivatives of these unprotected saccharides were well separated by normal-phase high-performance liquid chromatography and detected by ultraviolet absorption. Similar derivatization and fractionation of a partial acid hydrolyzate of chitin were equally successful resulting in the separation of Fmoc-glycinamido derivatives of di-N-acetylchitobiose to hepta-N-acetylchitoheptaose in the hydrolyzate. The reversibility of the Fmoc derivatization was demonstrated by treating the Fmoc-glycinamido derivative of N-acetylglucosamine with piperidine to generate its 1-N-glycyl-beta-saccharide derivative. The structure and stereochemistry of this product was confirmed by proton nuclear magnetic resonance spectroscopy. The 1-N-glycyl-beta-saccharide derivatives are stable intermediates for the formation of asparagine-linked neoglycoconjugates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylglucosamine
  • Fluorenes / chemistry*
  • Glycine / analogs & derivatives*
  • Glycine / chemistry
  • Glycoconjugates / metabolism*
  • Oligosaccharides / analysis*
  • Oligosaccharides / chemistry

Substances

  • Fluorenes
  • Glycoconjugates
  • Oligosaccharides
  • N-(9H-(fluoren-9-ylmethoxy)carbonyl)glycine
  • Glycine
  • Acetylglucosamine