title: Large oligosaccharide-based glycodendrimers.
abstract: Carbohydrate-based dendritic structures composed of 21 and 27 monosaccharide residues have been synthesized in a convergent manner from trisaccharide building blocks. The oligosaccharide AB2 monomers are based on a maltosyl beta(1-->6)galactose structure, which has been modified to include two methylamino groups at the primary positions of the glucosyl residues. Reductive alkylation of the secondary amino groups, with the innate formyl function of a second oligosaccharide monomer, allows for the chemoselective construction of dendritic wedges, while employing a minimal number of protecting groups. The first-generation dendron can be coupled either to another AB2 monomer, to give a second-generation dendron, or to a tris[2-(methylamino)ethyl]amine-based core moiety, to provide a carbohydrate-based dendrimer. Alternating alpha- and beta-glucosyl residues in the monomers and dendrons, simplifies 1H NMR spectra as a consequence of spreading out the anomeric proton signals. Monomers and dendrons were characterized by extensive one- and two-dimensional NMR spectroscopy in addition to FAB, electrospray, and MALDI-TOF mass spectrometry. Molecular dynamics simulations revealed similar conformations in the dendrons as in the isolated trisaccharide repeating units.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90095-1569, USA.
authors.forename: W Bruce
authors.initials: WB
authors.lastname: Turnbull
authors.forename: Stacey A
authors.initials: SA
authors.lastname: Kalovidouris
authors.forename: J Fraser
authors.initials: JF
authors.lastname: Stoddart
mesh_terms: D002240:Carbohydrate Sequence; D006001:Glycoconjugates / Q000138:chemical synthesis* / Q000737:chemistry; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009005:Monosaccharides / Q000737:chemistry; D009844:Oligosaccharides / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D006001:Glycoconjugates; D046911:Macromolecular Substances; D009005:Monosaccharides; D009844:Oligosaccharides