74513-17-0Relevant academic research and scientific papers
Protecting group-free immobilization of glycans for affinity chromatography using glycosylsulfonohydrazide donors
Hernandez Armada, Daniel,Santos, Jobette T.,Richards, Michele R.,Cairo, Christopher W.
, p. 109 - 116 (2015/10/19)
A variety of applications in glycobiology exploit affinity chromatography through the immobilization of glycans to a solid support. Although several strategies are known, they may provide certain advantages or disadvantages in how the sugar is attached to
ONE-POT SYNTHESIS OF ALPHA/BETA-O-GLYCOLIPIDS
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Page/Page column 31-32, (2008/12/04)
The present invention provides a one-pot method of preparing an unprotected α-O-glycolipid. The first step involves contacting a protected α-iodo sugar with a catalyst and a lipid comprising a hydroxy group, under conditions sufficient to prepare a protected α- O-glycolipid. The second step involves deprotecting the protected α-O-glycolipid under conditions sufficient to prepare the unprotected α-O-glycolipid, wherein the contacting and deprotecting steps are performed in a single vessel. The present invention also provides a one-pot method of preparing an unprotected β-O-glycolipid following the steps for the preparation of the unprotected α-O-glycolipid.
Simple preparations of alkyl and cycloalkyl α-glycosides of maltose, cellobiose, and lactose
Koto, Shinkiti,Hirooka, Motoko,Tashiro, Takako,Sakashita, Motokazu,Hatachi, Masaharu,Kono, Takayuki,Shimizu, Miho,Yoshida, Nahoko,Kurasawa, Sayaka,Sakuma, Natsuko,Sawazaki, Sunao,Takeuchi, Akihiro,Shoya, Naomi,Nakamura, Emi
, p. 2415 - 2424 (2007/10/03)
Alkyl, cycloalkyl, allyl, 4-pentenyl, and benzyl α-glycosides of maltose, cellobiose, and lactose were prepared via direct reaction of the free bioses with a binary AcBr-AcOH system, followed by glycosidation with alcohol using FeCl3 in MeNO2 or CH2Cl2, Zemple?n deacetylation, and the chromatographic resolution of the mixture. The respective β-biosides were obtained via the glycosidation in MeCN. Alkyl, cycloalkyl, allyl, 4-pentenyl, and benzyl α-glycosides of maltose, cellobiose, and lactose were prepared (17-77% yield; α/β = 70/30-96/4) via a direct reaction of the free disaccharides with a binary AcBr-AcOH mixture, followed by glycosidation with alcohol using FeCl3 in MeNO2 or CH2Cl2, Zemple?n deacetylation, and resolution of the anomeric mixture of glycosides by chromatography. Using MeCN as solvent for the glycosidation step, the corresponding β-biosides were also prepared (16-61% yield; α/β = 25/75-5/95).
Observations on chemical and enzymatic approaches to α-2,3-sialylated octyl β-lactoside
Turnbull, W.Bruce,Harrison, Jennifer A,Ravindranathan Kartha,Schenkman, Sergio,Field, Robert A
, p. 3207 - 3216 (2007/10/03)
A comparison of chemical and chemo-enzymatic syntheses of α-2,3-sialylated octyl lactoside is reported. The chemical approach, starting from lactose and sialic acid, required 14 steps and proceeded in 5% overall yield; poor α-selectivity in the sialylation step necessitated a difficult and low yielding separation of anomers. A chemoenzymatic approach, employing recombinant Trypanosoma cruzi trans-sialidase to effect the key sialylation reaction, required 10 steps and gave a similar overall yield. Whereas the chemo-enzymatic synthesis required only three chromatographic purification steps overall, the chemical synthesis required at least nine.
Optically active cyclophane receptors for mono- and disaccharides: The role of bidentate ionic hydrogen bonding in carbohydrate recognition
Droz, Anne Sophie,Neidlein, Ulf,Anderson, Sally,Seiler, Paul,Diederich, Francois
, p. 2243 - 2289 (2007/10/03)
A new family of optically active cyclophane receptors for the complexation of mono- and disaccharides in competitive protic solvent mixtures is described. Macrocycles (-)-(R,R,R,R)-1-4 feature preorganized binding cavities formed by four 1,1′-binaphthalene-2,2′-diyl phosphate moieties bridged in the 3,3′-positions by acetylenic or phenylacetylenic spacers. The four phosphodiester groups converge towards the binding cavity and provide efficient bidentate ionic H-bond acceptor sites (Fig. 2). Benzyloxy groups in the 7,7′-positions of the 1,1′-binaphthalene moieties ensure solubility of the nanometer-sized receptors and prevent undesirable aggregation. The construction of the macrocyclic framework of the four cyclophanes takes advantage of Pd0-catalyzed aryl-acetylene cross-coupling by the Sonogashira protocol, and oxidative acetylenic homo-coupling methodology (Schemes 2 and 8-10). Several cleft-type receptors featuring one 1,1′-binaphthalene-2,2′-diyl phosphate moiety were also prepared (Schemes 1, 6, and 7). An undesired side reaction encountered during the synthesis of the target compounds was the formation of naptho[b]furan rings from 3-ethynylnaphthalene-2-ol derivatives, proceeding via 5-endo-dig cyclization (Schemes 3-5). Computer-assisted molecular modeling indicated that the macrocycles prefer nonplanar puckered, cyclobutane-type conformations (Figs. 7 and 8). According to these calculations, receptor (-)-(R,R,R,R)-1 has, on average, a square binding site, which is complementary in size to one monosaccharide. The three other cyclophanes (-)-(R,R,R,R)-2-4 feature, on average, wider rectangular cavities, providing a good fit to one disaccharide, while being too large for the complexation of one monosaccharide. This substrate selectivity was fully confirmed in 1H-NMR binding titrations. The chiroptical properties of the cyclophanes and their nonmacrocyclic precursors were investigated by circular dichroism (CD) spectroscopy. The CD spectra of the acyclic precursors showed a large dependence from the number of 1,1′-binaphthalene moieties (Fig. 9), and those of the cyclophanes were remarkably influenced by the nature of the functional groups lining the macrocyclic cavity (Fig. 11). Profound differences were also observed between the CD spectra of linear and macrocyclic tetrakis(1,1′-binaphthalene) scaffolds, which feature very different molecular shapes (Fig. 10). In 1H-NMR binding titrations with mono- and disaccharides (Fig. 13), concentration ranges were chosen to favor 1:1 host - guest binding. This stoichiometry was experimentally established by the curve-fitting analysis of the titration data and by Job plots. The titration data demonstrate conclusively that the strength of carbohydrate recognition is enhanced with an increasing number of bidentate ionic host - guest H-bonds (Table 1) in the complex formed. As a result of the formation of these highly stable H-bonds, carbohydrate complexation in competitive protic solvent mixtures becomes more favorable. Thus, cleft-type receptors (-)-(R)-7 and (-)-(R)-38 with one phosphodiester moiety form weak 1:1 complexes only in CD3CN. In contrast, macrocycle (-)-(R,R,R,R)-1 with four phosphodiester groups undergoes stable inclusion complexation with monosaccharides in CD3CN containing 2% CD3OD. With their larger number of H-bonding sites, disaccharide substrates bind even more strongly to the four phosphodiester groups lining the cavity of (-)-(R,R,R,R)-2 and complexation becomes efficient in CD3CN containing 12% CD3OD. Finally, the introduction of two additional methyl ester residues further enhances the receptor capacity of(-)-(R,R,R,R)-3, and efficient disaccharide complexation occurs already in CD3CN containing 20% CD3OD.
Chemoenzymatic synthesis of α-(1→3)-Gal(NAc)-terminating glycosides of complex tertiary sugar alcohols
Qian, Xiangping,Sujino, Keiko,Otter, Albin,Palcic, Monica M.,Hindsgaul, Ole
, p. 12063 - 12072 (2007/10/03)
The scope of glycosyltransferases in the synthesis of oligosaccharide analogues has been expanded to include the use of "retaining" enzymes acting on complex tertiary C-branched disaccharide acceptors. The enzymes studied were α1,3-galactosyltransferase (
