Thesis (Ph.D.)--University of Wyoming, 2008. / Title from PDF title page (viewed on August, 3 2009). Includes bibliographical references (p. 131-139).

Thesis (Ph. D.)--Columbia University, 1924. / Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 23.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 185-211). Also available in electronic version.

Thesis (Ph. D.)--Oregon Graduate Center, 1986.

The three dimensional structure and dynamics of three biologically important oligosaccharides were probed using a range of NMR techniques. The solution structure of oligosaccharide moiety of was solved using conventional 1H - 1H ROESY data in conjunction with molecular dynamics simulations. It was evident from this study that the dominant conformation in free solution is similar to the structure of oligo-GM1 in complex with the B-subunit of the enteropathogenic cholera toxin. The solution dynamics of an analogue of globoside (Gb4-OEtTMS), a cellular receptor for an E. coli verotoxin, was also elucidated using conventional 1H - 1H ROESY data. However, it was not clear that these data alone could adequately model the structure. Additional distance restraints were derived from 1H - 1H NOE contacts between exchangeable and non-exchangeable protons measured in H2O/acetone-d6 solutions at low temperature (-15 °C). It was concluded on the basis of these studies that Gb4-OEtTMS is an extremely flexible sugar, however, the time- averaged conformation was similar to the proposed conformation of Gb4 in complex with a verotoxin (VT2e). In order to increase the structural information which may be measured from NMR spectroscopy, carbon-13 enriched carbohydrate moieties, commonly found in glycolipids and glycoproteins, were synthesised. Isotopically labelled N-acetyl neuraminic acid, a2,3 sialyl N-acetyl lactosamine (required for the synthesis of sialyl Lewis antigen) and a2,3 sialyl lactose (oligo-GM3), the core ganglioside which is required for the synthesis of more complex gangliosides (e.g. GM1), was accomplished using a mixture of enzymatic and synthetic methods. To test the applicability of heteronuclear NMR spectroscopy in the study of oligosaccharides, the solution structure and dynamics of [U-13C] oligo- GM3 was probed by recording three dimensional 13C-edited ROESY spectra, and long-range carbon-carbon and carbon-proton spin-coupling constants. Inter-residue ROEs could be unambiguously assigned from the 3D experiment, and these assignments contradict previous inter-residue ROE contacts published in the literature (based only on homonuclear data). Two additional inter-residue ROE contacts could be measured across the Gaibeta1-4Glc linkage. The solution conformation of [U-13C] oligo-GM3 in complex with wheat germ agglutinin was solved on the basis of 3D TRNOESY-HSQC data. Theoretical TRNOE intensities back-calculated from full relaxation matrix calculations performed on the X-ray crystal structures of the complex were consistent with experimentally measured values and confirmed the flexible nature of the Galbeta1-4Glc linkage when bound to the protein. Finally, carbon-13 enriched N-acetyl neuraminic acid and galactose were introduced into the glycan chains of an intact glycoprotein FcREA. 13C-1H HSQC data suggest that the two arms of the biantennary glycan experience two distinct magnetic environments.

Sugar mercaptals were partially methylated with Purdie's reagents in tetrahydrofuran as a solvent, and the relative reactivity of hydroxyl groups was determined by estimation of the ratio of mono-0̲-methyl ethers. The highest reactivity of the 2-hydroxyl group, followed by that of the 3-hydroxyl group, was accounted for by the inductive effect of the mercaptal group and the variation of the ratios among the sugar mercaptals was further explained by the intramolecular hydrogen bonding in the zig-zag conformation of sugar mercaptals. The exceptionally high reactivity of the 3-hydroxyl group of D̳-galactose diethyl mercaptal was also shown to be explicable in terms of the hydrogen bonding. An appreciable reactivity of the primary hydroxyl groups was noted and attributed to the least steric hindrance at this position. A mechanism for the Purdie methylation was proposed. Mg values of various mono-0̲-methyl sugars were recorded and some modifications in the separation of mono-0̲-methyl sugars were also described. 5-0̲-Methyl-L̳-arabinose and two crystalline derivatives were synthesized for the first time, and 2-0̲-methyl-L̳-arabonolactone, hitherto known as a sirup, was crystallized. / Science, Faculty of / Chemistry, Department of / Graduate

A number of conjugates of carbohydrates were prepared. Metal conjugates were synthesized in two different ways. Firstly, chelate coordination complexes were synthesized by forming salicylaldimine ligands derived from combinations of amino sugars [methyl-3,4,6-tri-0-acetyl-2-amino-2-deoxy-β-D-glucopyranoside, 1,3,4,6-tetra-0-acetyl-2-amino-2-deoxy-β-D-glucopyranose or 2-amino-2-deoxy-a,β-D-glucopyranose (glucosamine)] and either salicylaldehyde or 3-formyl-2-hydroxy-benzoic acid with subsequent complexation of these to copper (II) , cobalt (II), and zinc (II). A number of physical techniques were used to characterize these complexes including esr spectroscopy, visible absorption spectroscopy, mass spectrometry, nmr spectroscopy and magnetic susceptibility measurements. From the data provided by these techniques the copper-sugar complexes derived from salicylaldehyde were found in general to have the usual bis-bidentate structure. The copper complex derived from the amino-glycoside and 3-formyl-2-hydroxy-benzoic acid was found to be binuclear in structure containing two sugar moieties and two copper atoms. The second approach to forming metal sugar conjugates consisted of synthesizing organometallic π-complexes: ferrocenyl-sugar conjugates. A variety of organic- and water-soluble compounds were formed by reaction of amino, hydroxyl, or thio sugar groups with suitably substituted ferrocene derivatives. Thus organic soluble products were obtained from combinations of the sugars [l,3,4,6-tetra-0-acetyl-2-amino-2-deoxy- β-D-glucopyranose, l-thio-2,3,4,6-tetra-0-acetyl-β-D-glucopyranose, 1,2,5,6-di-0_-isopropylidene-α-D-glucofuranose and 1,2,3,4-di-o-isopropylidene-α-D-galactopyranose] with 1 - and 1,1'-ferrocenecarbonyl chlorides, N,N-dimethylaminomethylferrocene methiodide, (1-hydroxymethylferrocene)-p-toluenesulphonate and 2,4-dichloro-6-(1-hydroxymethylferrocene)-s-triazine. Water soluble products were prepared by deacetylation of some of the above compounds and by condensation of ferrocene carboxaldehyde with glucosamine to form the corresponding Schiff's base. Proton spin-lattice relaxation rates were used to assign the substituted cyclopentadienyl rings and to determine the relative spinning rates of the substituted and unsubstituted cyclopentadienyl rings. The chemistry of cyanuric chloride (2,4,6-trichloro-s-triazine), as a general means of derivatizing carbohydrates was also investigated. Thus, metals, hydrophobic alkyl groups and nitroxide spin labels were attached in various combinations to carbohydrates. A number of monosaccharide derivatives were formed including model glycolipids and a number of polysaccharides, cellulose, agarose, Sephadex, guar gum, xanthan gum and starch were spin labelled using this chemistry. For polysaccharides, information such as extent of derivatization, evidence for a covalent bond, environment of the triazine unit and the distance between triazine units was obtained. This chemistry was also extended to derivatize Bovine Serum Albumin, microporous glass beads and aluminum oxide. / Science, Faculty of / Chemistry, Department of / Graduate

Within the past few decades, interest in the field of aminosugar chemistry has been stimulated to a remarkable degree and the discovery and syntheses of a wide range of new aminosugars of differing types, for example of two monoamino-tetroses (12,19), nineteen monoamino-pentoses, two diamino-pentoses, thirty-three monoamino-hexoses, and eighteen diamino-hexoses (20) have been accomplished. It is well undterstood that the aminosugars, significant constituents in mnay biologically important materials (11), consist of substances that may be regarded a teh condesation products of an amine and a carbohydrate. Falling into this category are the 2-amino-hexoses which may be derived conceptually as the condensation of ammonia with carbon atom number 2 or a hexose. (4). Thus, D-glucose is the conceptual parent of D-glucosamine (i.e., 2-amino-2-deoxy-D-Glucose). D-allosamine is one of the rarer aminosugars about which very little is know concerning chemical properties and derivatives. A few studies have recently been made on the beta series of benzyl D-allosaminides after it was shown by Gross et al. (5) that the use of benzyl N-benzoyl-4, 6-0-benzylidene-β-D-glucosaminide as an intermediate in the synthesis of D-allosamine derivative proved fruitful for large-scale preparation of the β-D-allosaminide derivatives. This basic work has established conditions which have made it possible and desireable to conduct also an investigatin into the chemistry of the alpha series of D-allosaminides. Thus it appeared that a procedure involving the benzyl N-benzoyl-α-D-glucosaminide might well afford the alpha anomeric D-allosaminides. Although several benzyl N-benzoyl-hexosaminides are known (1,5,20), no information is yet available in the literature about benzyl N-benzoyl-α-D-glucosaminide from the standpoint of chemical properties and derivatives. To explore processes from making derivatives of D-allosamine particularly in the series of alpha-anomers, it is necessary to investigate the chemistry of benzyl N-benzoyl-α-D-glucosaminide and its derivatives, preparatory to an attempt to enter the alphaseries of D-allosaminides. Therefore, the principal interest of this investigation was to prepare and to investigate properties of benzyl N-benzoyl-α-D-glucosaminide and its derivatives, and to explore its utility as a possible precursor for the preparation of benzyl 3-0-benzoyl-α-D-allosaminide hydrochloride by the method analogous to the synthesis of the corresponding beta-anomer.

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