Oligo-, and Poly-saccharides

Rockenbauer, J. Hemela, G. Toth, and A. Gerecs, J. Carbohydrates, Nucleosides, Nucleotides, 1977, 4, 23. 

The use of and natural-abundance n.m.r. spectroscopy in structural investigations of oligo- and poly-saccharides is now commonplace, and these techniques are particularly helpful in assigning the configurations of inter-sugar linkages. They were readily applied to gentiodextrins and their derivatives and Klebsiella serotype and K62 polysaccharides, all of which are com- 

The applications of n.m.r. spectroscopy to carbohydrate chemistry have been ably reviewed by Perlin.  

Both and high-resolution H n.m.r. spectroscopy have been used in determining the structure and conformation of the polyene macrolide antibiotic pimari-cin. The value of the anomeric coupling constant, J.jc-i m-i 156 Hz, for the mycosaminyl residue of N-acetylpimaricin indicated that the sugar is P-linked to the macrolide ring. 

Kolosova, T. A. Tsetsokho, and V. P, Panov, Tezisy Doklady Pses. Konf. Khim. Fiz. Tsellyui, 

High-resolution n.m.r. spectroscopy of D-glucobioses in deuterium oxide has shown that protons on, or vicinal to, the carbon atom involved in the glycosidic linkage are shifted downfield. De Bruyn s group has also assigned the 300 MHz H n.m.r. spectra of raffinose and melezitose (in DjO) and sucrose octa-acetate (in [ He]benzene and [ H]chloroform, etc.) with the help of homo-INDOR experiments. 

10 Hz lower when H-1 is axial than when it is equatorial. The Vhoi, h-i values can therefore be used for the determination of conformational equilibria. In agreement with this finding, tri-( -acetylamylose and tri-O-acetylcellulose have Vuc-i,iH-i values of 176 and 163 Hz, respectively. The i C- F coupling constants have been obtained from the proton-decoupled C n.m.r. spectra of a number of glycosyl fluorides values were found to be negative and to be 

A thorough analysis of the C n.m.r. spectra of methyl aldopento- and aldo-hexo-furanosides and several cyclopentanols has enabled the C chemical shifts to be correlated with the configurations and other stereochemical features of vicinal diol groupings. Values for both /uc-i,f and /i c-2.p furanosyl 

D-glucans with mixed linkages the resonances were assigned by comparison with the spectra of D-glucose and its 0-methyl derivatives and those of differently linked D-gluco-bioses and -trioses. This technique enabled the compositions, 

The use of C n.m.r. spectroscopy in elucidating the structures of monosaccharides, polysaccharides, nucleosides, and nucleotides has been reviewed. A study of the tautomerism of formycin and related compounds using C n.m.r. spectroscopy is noted in Chapter 21.  

Chemical shifts have been reported for a number of compounds derived from sucrose, including D- a/ac/o-sucrose and 6,6 -dichloro-6,6 -dideoxy- and r,6,6 -trichloro-r,6,6 -trideoxy-sucrose.  

803 Tori, S. Seo, Y. Yoshimura, M. Nakamura, Y. Tomita, and H. Ishii, Tetrahedron Letters, 1976, 4167. 

Aldobioses form acetohalogeno compounds when their octaacetates are 

In 1896, Fischer developed the phenylhydrazine test for the detection of hydrolytic scission of disaccharides, especially by enzymes this depends on the fact that the phenylosazones of disaccharides are soluble in hot water, whereas those of the monosaccharides are not. Lactose is hydrolyzed by emulsin (1894) and by lactase it is not fermentable by yeast, and is unaffected by invertase (1894). An extract of the small intestine of horses and cattle, especially from young animals, hydrolyzes lactose (1896). The action of enzymes on lactose allowed it to be classified, along with cellobiose and maltose, with the normal (and not the y-type of) methyl glucoside (1914). In the discussion of maltose, the relationship of lactose to the /9-series will be mentioned later. 

Sucrose is fermented by nearly all yeasts (1894,1898). Inversion precedes fermentation (1895). Of various animal secretions tried, the only one effective in cleaving sucrose was that from the mucous membrane of the small intestines of several animals (1896). Sucrose was found to be unaffected by emulsin (in 1894). An approximately correct formula for sucrose had been published in 1883 its shortcomings were the incorrect ring size for the glucose residue and the uncertainty regarding configurations at the interlinked carbonyl groups. 

Fischer performed a few experiments with the natural disaccharide trehalose. It does not react with phenylhydrazine. A diastase from. green malt has no action on it Froliberg yeast has a weak action (1895). Carp blood hydrolyzes it rapidly, in contrast to the blood of other fishes. Extracts of the mucous membrane from the small intestines of horses and cattle are also active (1906). A. Kalanther, in Fischer s laboratory, found, in 1898. that wine yeasts also hydrolyze this disaccharide. 

On the basis of reports in the literature, Fischer considered gentiobiose to be an 0-/3-D-glucosylglucose (see cellobiose, p. 30). 

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Even if the main focus on the research activities were directed towards structural studies on carbohydrates of natural origin, the synthesis of model substances, deriva-tization of oligo- and poly-saccharides, oxidation, and reduction of carbohydrates, and identification of the products all were performed during this time. 

Oligo- and Poly-saccharide Synthesis with Sucrose Analogues... 

Gibbs energy change is available to enable synthesis of oligo- and poly-saccharides by sucrose-type enzymes that use sucrose as a substrate for the transfer of glucose or fructose. 

Molecular weight Glycosyl sequence in oligo- and poly-saccharides... 

Subjecting monosaccharides to conditions of acid hydrolysis is only of importance in measuring the expected hydrolysis losses during hydrolysis of oligo- and poly-saccharides. Hydrolysis losses may be predicted, based on either the absolute or the relative decomposition of monosaccharides. Absolute decompositions are based on decomposition of monosaccharides. Relative decompositions are based on studies wherein several methods of hydrolysis were applied to the same samples for various lengths of time in this Section, these are classified under the type of acid that causes the least decomposition (that is the largest yield of monosaccharides liberated), because this acid is usually the one of principal concern in the particular study. 

These experiments provide identification of the through-bond spin coupling network as well as through-space proximity between spins. Examples of the application of these techniques have demonstrated the efficiency of these techniques in establishing the assignment, sequence and linkage site information for oligo- and poly-saccharides [59-60, 62-65], and for saponins [29]. 

They heated a solution of D-glucose with a phenolsulfonic acid resin at 70° for 72 hours. A complex mixture of oligo- and poly-saccharides was formed, from which gentiobiose was isolated. Laminaribiose was produced by the action of a cation-exchange resin on D-glucose.142... 

A. S. Shashkov, A. I. Usov, Y. A. Knirel, B. A. Dmitriev, and N. K. Kochetkov, Determination of absolute and anomeric configurations of monosaccharides in oligo- and poly-saccharides by glycosylation effects in 13C-NMR spectra, Bioorg. Khim., 7 (1981) 1364-1371. 

N. K. Kochetkov, O. S. Chizhov, and A. S. Shashkov, Dependence of 13C chemical shifts on the spatial interaction of protons, and its application in structural and conformational studies of oligo- and poly-saccharides, Carbohydr. Res., 133 (1984) 173-185. 

Oxidation of methylated sugars with nitric acid was used extensively by early workers for locating the position of unsubstituted hydroxyl groups.116 Cleavage of carbon-carbon bonds appears to be facilitated by the presence of such catalysts as vanadium salts. As hot nitric acid acts as a hydrolyzing agent as well as an oxidant, oligo- and poly-saccharides may be used directly. 

I. Hoffman, B. Lindberg, and S. Svensson, Determination of the anomeric configuration of sugar residues in acetylated oligo- and poly-saccharides by oxidation with chromium trioxide in acetic acid, Acta Chem. Scand., 26 (1972) 661-666. 

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