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Synlett 2003(9): 1315-1318
DOI: 10.1055/s-2003-40324
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Efficient Synthesis of Two HNK-1 Related Pentasaccharides

Frederic Belota, Albin Otterb, Minoru Fukudaa, Ole Hindsgaul*a,b
The Burnham Institute, 10901 North Torrey Pines Rd., La Jolla, CA, USA 92122
University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada T6G 2G2
Fax: +1(780)4927705; e-Mail: ole.hindsgaul@ualberta.ca;
Further Information

Publication History

Received 23 January 2002
Publication Date:
30 June 2003 (online)

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Abstract

Two pentasaccharides, representative of those found on complex N-glycans, were synthesized for use as potential substrates for sulfotransferases. The synthesis was achieved by the addition of a disaccharide donor β-d-GlcA(1→3)α-d-Gal-trichloroacetimidate to the two acceptor trisaccharides β-d-GlcNAc(1→6)α-d-Man(1→6)β-d-Man-O-octyl (15) and β-d-GlcNAc(1→2)α-d-Man(1→6)β-d-Man-O-octyl (14). After deprotection, the two pentasaccharides 1 and 2 were characterized by 1H NMR spectroscopy.

Key words

pentassacharides - HNK-1 - N-glycans

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Data recorded in D2O at 600 MHz, and 27.0±0.1 °C; concentration ca. 8 mM; chemical shifts are relative to external 0.1% acetone set at 2.225 ppm measured in a separate sample under identical experimental conditions. Even under strict temperature control, chemical shifts are not reproducible to three decimals, however, within a given experiment at 600 MHz, signals can be distinguished accurately to this precision.

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Correct glycosidic linkages are confirmed by the following inter-residue NOEs (s for strong, m for medium and w for weak interactions). 1: H1βGlcA-H3βGal (s) and H1βGlcA-H4Gal (m); H1βGal-H4βGlcNAc (likely s, overlaps with H1/H5βGal); H1βGlcNAc-H6a/bαMan (s) and H1βGlcNAc-H5αMan (w); H1αMan-H6bβMan (s) and H1αMan-H6aβMan (w) and H1αMan-H5βMan (w). 2: H1βGlcA-H3βGal (s) and H1βGlcA-H4βGal (m); H1βGal-H4βGlcNAc (likely s, overlaps with H1/H5βGal); H1βGlcNAc-H2αMan (s) and H1βGlcNAc-H1αMan (s); H1αMan-H6bβMan (s) and H1αMan-H6aβMan (w) and H1αMan-H5βMan (w).
Furthermore, typical H1-H3 and H1-H5 intra-residue NOEs were observed for all β-glycosides. Taken together with the coupling constants, this confirms that all pyranose rings adopt the normal chair form.

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HRMS calcd for C40H69NNaO27 (1 and 2): 1018.3955; found 1: 1018.3961; 2:1018.3959