- A facile and stereoselective synthesis of 3,4,6-tri-O-acetyl-2-deoxy-2- phthalimido-β-D-glucopyranosyl chloride
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Acetylation of D-glucosamine catalysed by sulfuric acid and N-phthaloylation of the glucosyl acetate yielded 1,3,4,6- tetra-O-acetyl-2- deoxy-2-phthalimido-α-D-glucopyranose. This gave the corresponding pure β-glucosyl chloride upon treatment with PCl5-BF3. An anomeric chlorination with thionyl chloride combined with the Lewis acids (ZnCl2, SnCl4 and BiCl3) resulted in an α/β anomer mixture.
- Cao, Zhiling,Liu, Wenjie,Qu, Yingying,Yao, Guowei,Gao, Dachao,Liu, Weiwei
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- Differently N-protected 3,4,6-tri-O-acetyl-2-amino-2-deoxy-d-glucopyranosyl chlorides and their application in the synthesis of diosgenyl 2-amino-2-deoxy-β-d-glucopyranoside
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Four differently N-protected 3,4,6-tri-O-acetyl-2-amino-2-deoxy-d- glucopyranosyl chlorides were synthesized and used as glycosyl donors in reactions with diosgenin. The following amine group protections were tested: trifluoroacetyl (TFA), 2,2,2-trichloroethoxycarbonyl (Troc), phthaloyl (Phth), and tetrachlorophthaloyl (TCP). Products of glycosylation were deprotected to yield diosgenyl 2-amino-2-deoxy-β-d-glucopyranoside. The efficiency of the procedures is discussed. Additionally, a single-crystal X-ray diffraction analysis for 3,4,6-tri-O-acetyl-2-deoxy-2-tetrachlorophthalimido-β-d- glucopyranosyl chloride is reported. Orientations of the pyranose substituents as well as the planarity of the acetoxy and phthalimide groups in the crystal lattice are discussed. Structural evidence is presented for a mesomeric effect in both groups. The preference of the cis over trans orientation of the acetoxy group is confirmed in the crystal lattice.
- Bednarczyk, Dorota,Walczewska, Agata,Grzywacz, Daria,Sikorski, Artur,Liberek, Beata,Myszka, Henryk
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- Enhanced binding to DNA and topoisomerase I inhibition by an analog of the antitumor antibiotic rebeccamycin containing an amino sugar residue
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Many antitumor agents contain a carbohydrate side chain appended to a DNA-intercalating chromophore. This is the case with anthracyclines such as daunomycin and also with indolocarbazoles including the antibiotic rebeccamycin and its tumor active analog, NB506. In each case, the glycoside residue plays a significant role in the interaction of the drug with the DNA double helix. In this study we show that the DNA-binding affinity and sequence selectivity of a rebeccamycin derivative can be enhanced by replacing the glucose residue with a 2'-aminoglucose moiety. The drug-DNA interactions were studied by thermal denaturation, fluorescence, and footprinting experiments The thermodynamic parameters indicate that the newly introduced amino group on the glycoside residue significantly enhanced binding to DNA by increasing the contribution of the polyelectrolyte effect to the binding free energy, but does not appear to participate in any specific molecular contacts. The energetic contribution of the amino group of the rebeccamycin analog was found to be weaker than that of the sugar amino group of daunomycin, possibly because the indolocarbazole derivative is only partially charged at neutral pH. Topoisomerase I-mediated DNA cleavage studies reveal that the OH→NH2 substitution does not affect the capacity of the drug to stabilize enzyme-DNA covalent complexes. Cytotoxicity studies with P388 leukemia cells sensitive or resistant to camptothecin suggest that topoisomerase I represents a privileged intracellular target for the studied compounds. The role of the sugar amino group is discussed. The study provides useful guidelines for the development of a new generation of indolocarbazole- based antitumor agents.
- Bailly, Christian,Qu, Xiaogang,Anizon, Fabrice,Prudhomme, Michelle,Riou, Jean-Francois,Chaires, Jonathan B.
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- Structure activity relationships of N-linked and diglycosylated glucosamine-based antitumor glycerolipids
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1-O-Hexadecyl-2-O-methyl-3-O-(2′-amino-2′-deoxy-β-D- glucopyranosyl)-snglycerol (1) was previously reported to show potent in vitro antitumor activity on a range of cancer cell lines derived from breast, pancreas and prostate cancer. This compound was not toxic to mice and was inactive against breast tumor xenografts in mice. This inactivity was attributed to hydrolysis of the glycosidic linkage by glycosidases. Here three N-linked (glycosylamide) analogs 2-4, one triazole-linked analog 5 of 1 as well as two diglycosylated analogs 6 and 7 with different stereochemistry at the C2-position of the glycerol moiety were synthesized and their antitumor activity against breast (JIMT-1, BT-474, MDA-MB-231), pancreas (MiaPaCa2) and prostrate (DU145, PC3) cancer cell lines was determined. The diglycosylated analogs 1-O-hexadecyl-2(R)-, 3-O-di-(2′-amino-2′-deoxy- β-D- glucopyranosyl)-sn-glycerol (7) and the 1:1 diastereomeric mixture of 1-O-hexadecyl- 2(R/S), 3-O-di-(2′-amino-2′-deoxy-β-D- glucopyranosyl)-sn-glycerol (6) showed the most potent cytotoxic activity at CC50 values of 17.5 μM against PC3 cell lines. The replacement of the O-glycosidic linkage by a glycosylamide or a glycosyltriazole linkage showed little or no activity at highest concentration tested (30 μM), whereas the replacement of the glycerol moiety by triazole resulted in CC50 values in the range of 20 to 30 μM. In conclusion, the replacement of the O-glycosidic linkage by an N-glycosidic linkage or triazole-linkage resulted in about a two to three fold loss in activity, whereas the replacement of the methoxy group on the glycerol backbone by a second glucosamine moiety did not improve the activity. The stereochemistry at the C2-position of the glycero backbone has minimal effect on the anticancer activities of these diglycosylated analogs.
- Ogunsina, Makanjuola,Pan, Hangyi,Samadder, Pranati,Arthur, Gilbert,Schweizer, Frank
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- Direct and efficient monitoring of glycosyltransferase reactions on gold colloidal nanoparticles by using mass spectrometry
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A simple and efficient assay for glycosyltransferase activity on gold colloidal nanoparticles (GCNPs) by using laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS) is demonstrated by the enzymatic synthesis of the Lewis X trisaccharide on GCNPs containing GlcNAc residues. GCNPs containing multivalent sugars were well dispersed in aqueous solution and proved to be excellent acceptor substrates for the glycosyltransferase reaction. Direct LDI-TOF MS analysis of these GCNPs provided the ion peaks of the sugar derivatives, chemisorbed through S-Au linkages onto the GCNPs, even in the presence of contaminants such as proteins and salts. Thus, it enabled the rapid and direct detection of the enzymatic reaction on the GCNPs by subjecting a small amount (0.15 μL) of the reaction mixture to MS analysis without purification. Subsequent MS/MS analyses (LDI-LIFT-TOF/TOF method) of the product-carrying GCNPs enabled the structures of the sugar derivatives that had been constructed on the GCNPs by enzymatic glycosylation to be determined. A quantitative inhibition assay for glycosyltransferase by using LDI-TOF MS analysis on the GCNPs was demonstrated by using uridine 5′-di-phosphate (UDP) as the inhibitor. This simple assay was then applied to the detection of the enzymatic activity of a crude cell extract of Escherichia coli, which produces Neisseria meningitidis β-1,4-galactosyltransferase (β-1,4-GalT). In this case, the GCNPs were roughly purified by means of ultrafiltration to remove the buffer and detergents before MS analysis. That the GCNPs are dissolved in solution in the reaction medium but are solid in the purification process is greatly advantageous for the simple and efficient detection of enzymatic activity in crude biological samples. Thus, GCNPs containing a variety of biomolecules may become a versatile and efficient tool for the rapid and direct monitoring of metabolism (metabolomics) in living cells when combined with LDI-TOF MS analysis.
- Nagahori, Noriko,Nishimura, Shin-Ichiro
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- Glycoconjugate probes containing a core-fucosylated N-glycan trisaccharide for fucose lectin identification and purification
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Glyco-PAMAM dendrimers and glyco-agarose beads bearing a core-fucosylated N-glycan trisaccharide GlcNAcβ1,4(Fucα1,6)GlcNAc or a non-fucose disaccharide GlcNAcβ1,4GlcNAc were successfully synthesized and characterized by monosaccharide analysis with HPAEC-PAD technique. These glycoconjugates as fucose lectin probes were applied in fucose-specific lectin detection and purification. The model fucose lectin AAL indicated binding activity with the FITC-labeled PAMAM carrying core-fucose trisaccharide. An affinity chromatography column stuffed with the agarose beads carrying core-fucosylated trisaccharide exhibited a good specificity in purification of AAL than non-fucose disaccharide agarose beads. These novel glycoconjugates bearing the precise and simplified core-fucose N-glycan structure provided a potential application for core-fucose-specific lectin discovery.
- Cai, Deqin,Xun, Chaochao,Tang, Feng,Tian, Xiaobo,Yang, Liyun,Ding, Kan,Li, Wenzhe,Le, Zhiping,Huang, Wei
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- A practical synthesis of a (1→6)-linked β-D-glucosamine nonasaccharide
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A (1→6)-β-D-glucosamine nonasaccharide was convergently synthesized using isopropyl thioglycosides as donors. Anomeric acetylated glucosamine derivatives were proved to be good acceptors in the NIS/TMSOTf catalyzed glycosylation. The target nonasaccharide showed a mild antitumor activity against H22 on the preliminary mice tests.
- Yang, Feng,Du, Yuguo
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- Synthesis and characterization of N-acyl-tetra-O-acyl glucosamine derivatives
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Novel 1,3,4,6-tetra-O-acyl-N-acyl-d-glucosamine derivatives were synthesized from glucosamine hydrochloride (GlcN·HCl) by the acylation with pyridine as a catalyst. A derivative of tetra-O-acetyl glucosamine contained ketoprofen, a non-steroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic effects, was first synthesized. In analysis of the NMR spectra, the ratio of α:β-anomer showed that penta-acyl-d- glucosamine derivatives and N-acetylated glucosamines containing O-acyl groups have been only the α-anomer. Meanwhile, both the intermediates and the glucoconjugate compound of ketoprofen have only the β-anomer.
- Dang, Chi-Hien,Nguyen, Cong-Hao,Nguyen, Thanh-Danh,Im, Chan
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- Synthesis and immunological evaluation of a low molecular weight saccharide with TLR-4 agonist activity
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The paucity of FDA approved adjuvants renders the synthesis, characterization, and use of new compounds as vaccine adjuvants, a necessity. For this purpose, a novel saccharide analog has been synthesized from glucosamine, pyruvylated galactose and 1,4-cyclohexanediol and its biological efficacy was determined in innate immune cells. More specifically, we assessed the production of pro-inflammatory cytokines from the murine monocyte cell line, Raw 264.7 and from C57 BL/6 mouse peritoneal macrophages following exposure to the saccharide analog. Our data conclude that the novel saccharide has immunostimulatory activity on mouse macrophages as indicated by the elevated levels of IL-6 and TNF-α in culture supernatants. This effect was TLR-4-dependent but TLR-2-independent. Our data, suggest TLR-4 agonism; a key feature of vaccine adjuvants.
- Basava, Vikram,Romlein, Heather,Bitsaktsis, Constantine,Marzabadi, Cecilia H.
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- A Fluorescent Transport Assay Enables Studying AmpG Permeases Involved in Peptidoglycan Recycling and Antibiotic Resistance
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Inducible AmpC β-lactamases deactivate a broad-spectrum of β-lactam antibiotics and afford antibiotic resistance in many Gram-negative bacteria. The disturbance of peptidoglycan recycling caused by β-lactam antibiotics leads to accumulation of GlcNAc-1,6-anhydroMurNAc-peptides, which are transported by AmpG to the cytoplasm where they are processed into AmpC inducers. AmpG transporters are poorly understood; however, their loss restores susceptibility toward β-lactam antibiotics, highlighting AmpG as a potential target for resistance-attenuating therapeutics. We prepare a GlcNAc-1,6-anhydroMurNAc-fluorophore conjugate and, using live E. coli spheroplasts, quantitatively analyze its transport by AmpG and inhibition of this process by a competing substrate. Further, we use this transport assay to evaluate the function of two AmpG homologues from Pseudomonas aeruginosa and show that P. aeruginosa AmpG (Pa-AmpG) but not AmpP (Pa-AmpP) transports this probe substrate. We corroborate these results by AmpC induction assays with Pa-AmpG and Pa-AmpP. This fluorescent AmpG probe and spheroplast-based transport assay will enable improved understanding of PG recycling and of permeases from the major facilitator superfamily of transport proteins and may aid in identification of AmpG antagonists that combat AmpC-mediated resistance toward β-lactam antibiotics.
- Perley-Robertson, G. Evan,Yadav, Anuj K.,Winogrodzki, Judith L.,Stubbs, Keith A.,Mark, Brian L.,Vocadlo, David J.
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- Improved synthesis of 1,2-trans-acetates and 1,2-trans ethyl 1-thioglycosides derived from 3,4,6-tri-o-acetyl-2-deoxy-2-phthalimido-D-hexopyranosides
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Effective one-pot synthesis of 1,2-trans-acetates 4b, 5b and 6a derived from N-phthaloyl-protected D-glucosamine, D-galactosamine and D-mannosamine, respectively, is presented. Anomerisation of the corresponding 1,2-cis-acetates 4a, 5a and 6b and direct conversion of all of them to 1,2-trans ethyl 1-thioglycosides 7, 8 and 9 are also described and discussed.
- Vesely, Jan,Ledvina, Miroslav,Jindrich, Jindrich,Saman, David,Trnka, Tomas
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- BIFUNCTIONAL COMPOUND AND ITS USE IN IMMUNOTHERAPY
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The invention relates to a bifunctional compound that is, on one side, an agonist of the TLR4 and, on the other side, an important inhibitor of the PSMA. Said compound is useful in immunotherapy for the treatment and/or prevention of prostate cancer. Therefore, the invention also relates to the use of the compound and to the pharmaceutical composition comprising it.
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Page/Page column 18-19
(2021/02/12)
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- Selectively Deoxyfluorinated N-Acetyllactosamine Analogues as 19F NMR Probes to Study Carbohydrate-Galectin Interactions
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Galectins are widely expressed galactose-binding lectins implied, for example, in immune regulation, metastatic spreading, and pathogen recognition. N-Acetyllactosamine (Galβ1-4GlcNAc, LacNAc) and its oligomeric or glycosylated forms are natural ligands of galectins. To probe substrate specificity and binding mode of galectins, we synthesized a complete series of six mono-deoxyfluorinated analogues of LacNAc, in which each hydroxyl has been selectively replaced by fluorine while the anomeric position has been protected as methyl β-glycoside. Initial evaluation of their binding to human galectin-1 and -3 by ELISA and 19F NMR T2-filter revealed that deoxyfluorination at C3, C4′ and C6′ completely abolished binding to galectin-1 but very weak binding to galectin-3 was still detectable. Moreover, deoxyfluorination of C2′ caused an approximately 8-fold increase in the binding affinity towards galectin-1, whereas binding to galectin-3 was essentially not affected. Lipophilicity measurement revealed that deoxyfluorination at the Gal moiety affects log P very differently compared to deoxyfluorination at the GlcNAc moiety.
- Kurfi?t, Martin,Dra?ínsky, Martin,?ervenková ??astná, Lucie,Cu?ínová, Petra,Hamala, Vojtěch,Hovorková, Michaela,Bojarová, Pavla,Karban, Jind?ich
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supporting information
p. 13040 - 13051
(2021/08/07)
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- Glycosidic linkage, N-acetyl side-chain, and other structural properties of methyl 2-acetamido-2-deoxy-β-d-glucopyranosyl-(1→4)-β-d-mannopyranoside monohydrate and related compounds
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The crystal structure of methyl 2-acetamido-2-deoxy-β-d-glycopyranosyl-(1→4)-β-d-mannopyranoside monohydrate, C15H27NO11·H2O, was determined and its structural properties compared to those in a set of mono- and disaccharides bearing N-acetyl side-chains in βGlcNAc aldohexopyranosyl rings. Valence bond angles and torsion angles in these side chains are relatively uniform, but C - N (amide) and C - O (carbonyl) bond lengths depend on the state of hydrogen bonding to the carbonyl O atom and N - H hydrogen. Relative to N-acetyl side chains devoid of hydrogen bonding, those in which the carbonyl O atom serves as a hydrogen-bond acceptor display elongated C - O and shortened C - N bonds. This behavior is reproduced by density functional theory (DFT) calculations, indicating that the relative contributions of amide resonance forms to experimental C - N and C - O bond lengths depend on the solvation state, leading to expectations that activation barriers to amide cis-trans isomerization will depend on the polarity of the environment. DFT calculations also revealed useful predictive information on the dependencies of inter-residue hydrogen bonding and some bond angles in or proximal to β-(1→4) O-glycosidic linkages on linkage torsion angles φ and ψ. Hypersurfaces correlating φ and ψ with the linkage C - O - C bond angle and total energy are sufficiently similar to render the former a proxy of the latter.
- Carmichael, Ian,Meredith, Reagan J.,Oliver, Allen G.,Serianni, Anthony S.,Zhang, Wenhui
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p. 287 - 297
(2020/03/17)
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- Reduction Triggered in Situ Polymerization in Living Mice
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"Smart"biomaterials that are responsive to physiological or biochemical stimuli have found many biomedical applications for tissue engineering, therapeutics, and molecular imaging. In this work, we describe in situ polymerization of activatable biorthogonal small molecules in response to a reducing environment change in vivo. We designed a carbohydrate linker- and cyanobenzothiazole-cysteine condensation reaction-based small molecule scaffold that can undergo rapid condensation reaction upon physiochemical changes (such as a reducing environment) to form polymers (pseudopolysaccharide). The fluorescent and photoacoustic properties of a fluorophore-tagged condensation scaffold before and after the transformation have been examined with a dual-modality optical imaging method. These results confirmed the in situ polymerization of this probe after both local and systemic administration in living mice.
- Chen, Zixin,Cui, Lina,Fréchet, Jean M. J.,Gambhir, Sanjiv S.,Kierstead, Paul H.,Kothapalli, Sri-Rajasekhar,Liu, Jun,Ma, Xiaowei,Rao, Jianghong,Smith, Bryan Ronain,Taylor, Madelynn,Vivona, Sandro
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supporting information
p. 15575 - 15584
(2020/10/18)
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- Regioselective Glycosylation Strategies for the Synthesis of Group Ia and Ib Streptococcus Related Glycans Enable Elucidating Unique Conformations of the Capsular Polysaccharides
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Group B Streptococcus serotypes Ia and Ib capsular polysaccharides are key targets for vaccine development. In spite of their immunospecifity these polysaccharides share high structural similarity. Both are composed of the same monosaccharide residues and
- Del Bino, Linda,Calloni, Ilaria,Oldrini, Davide,Raso, Maria Michelina,Cuffaro, Rossella,Ardá, Ana,Codée, Jeroen D. C.,Jiménez-Barbero, Jesús,Adamo, Roberto
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supporting information
p. 16277 - 16287
(2019/11/14)
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- Chemoenzymatic Synthesis of Glycoconjugates Mediated by Regioselective Enzymatic Hydrolysis of Acetylated 2-Amino Pyranose Derivatives
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Highly regioselective deprotection of a series of 2-amino pyranose building blocks was achieved by enzymatic hydrolysis. These monodeprotected intermediates were successfully used in the synthesis of a variety of glycoconjugate derivatives with a core of glucosamine or galactosamine, including neo-glycoproteins and glycosphingolipids. The hydrolysis catalyzed by acetylxylan esterase from Bacillus pumilus (AXE) is suitable for the synthesis of neo-glycoproteins with an N-acetyl glucosamine core. The hydrolysis catalyzed by Candida rugosa lipase (CRL) was successfully applied in the preparation of new sialylated glycolipids starting from glucosamine building blocks protected as phthalimide. This chemoenzymatic approach can be used for the preparation of new glycoconjugate products with anticancer activity.
- Zheng, Changping,Bavaro, Teodora,Tengattini, Sara,Mascherpa, Andrea Gualla,Sollogoub, Matthieu,Zhang, Yongmin,Terreni, Marco
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supporting information
p. 3622 - 3631
(2019/06/17)
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- Preparation method of tetra-O-acetyl-2-phthalyl imidogen-beta-glucose
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The invention provides a synthesis method of tetra-O-acetyl-2-phthalyl imidogen-beta-glucose. The tetra-O-acetyl-2-phthalyl imidogen-alpha-glucose is used as a starting raw material, the raw materialsare easy to obtain and low in cost, under the action of acetic acid, acetic anhydride and a catalyst namely scandium trifluoromethane sulfonate, 1-site isomerization is performed, and the tetra-O-acetyl-2-phthalyl imidogen-beta-glucose is generated; and compared with previous methods, the synthesis method disclosed by the invention has the advantage that the production cost of the important intermediate namely the tetra-O-acetyl-2-phthalyl imidogen-beta-glucose is substantially reduced. The technical technology is mild in condition, products are simple and convenient to separate and high in yield, preparation industrialization of the tetra-O-acetyl-2-phthalyl imidogen-alpha-glucose is facilitated, and development and production of lower-reach series medicines and functional products are promoted.
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Paragraph 0010; 001
(2019/12/10)
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- Monophosphate A conjugated-Tn anti-tumor vaccine and application thereof
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The invention provides a monophosphate A conjugated-Tn anti-tumor vaccine. The monophosphate A conjugated-Tn anti-tumor vaccine is a compound shown in a formula (I), namely Y-L-X(I). The monophosphateA conjugated-Tn anti-tumor vaccine is characterized in that a compound of the second generation of TLR4 ligand I of wholly new structure in the formula (I) is used for replacing MPLA (modified polylactic acid) and coupling with a compound (Tn) with clinical development potential in a formula (II), so as to obtain the two-component vaccine with a clear structure and a stronger anti-tumor function;the anti-tumor application prospect is better.
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Paragraph 0052; 0057-0059
(2019/09/17)
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- Unsaturated hyaluronate tetrasaccharide and preparation method thereof
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The invention relates to unsaturated hyaluronate tetrasaccharide and a preparation method of unsaturated hyaluronate tetrasaccharide. Unsaturated hyaluronate tetrasaccharide is an ionic compound; a negative ion structure general formula of unsaturated hyaluronate tetrasaccharide is shown as formula (1) as shown in the specification; and X is hydrogen or methyl. Sites 4 and 5 of terminal glucuronicacid are set as unsaturated double bonds, so that unsaturated hyaluronate tetrasaccharide has as strong water absorptivity as common hyaluronic acid and stronger oxidation resistance.
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Paragraph 0040-0043
(2019/10/01)
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- Asymmetric Total Synthesis of Brasilicardins
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Brasilicardins, bacterial diterpenoid natural products that display highly potent immunosuppressive activity, are promising immunosuppressant drug candidates. Structurally, they can be described as hybrids of terpenoids, amino acids, and saccharides, and share a characteristic highly strained anti-syn-anti-fused perhydrophenanthrene terpenoid scaffold (ABC-ring system) with two quaternary asymmetric carbon atoms. A unified and stereoselective total synthesis of all four brasilicardins has been designed based on the strategic use of an intramolecular conjugate addition. The ABC-ring system was initially constructed with high stereocontrol by novel intramolecular conjugate additions of Weinreb amides and in situ generated (Z)-vinyl copper species. The late-stage common intermediate was subjected to stereoselective installation of the amino acid component, followed by introduction of the saccharide unit via glycosylation to accomplish the total synthesis of brasilicardins A–D. Our synthesis offers opportunities to synthesize various brasilicardin analogues for biological and pharmacological investigations.
- Yoshimura, Fumihiko,Itoh, Ryusei,Torizuka, Makoto,Mori, Genki,Tanino, Keiji
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supporting information
p. 17161 - 17167
(2018/12/11)
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- Ionic-liquid supported rapid synthesis of an: N -glycan core pentasaccharide on a 10 g scale
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A new and efficient Ionic Liquid-Supported Oligosaccharide Synthesis (ILSOS) strategy for an N-linked core pentasaccharide on a 10 g scale is reported. This new ILSOS includes a new spacer for an IL support, a new tagging strategy, and fast, efficient and orthogonal removal of the ionic-liquid support, producing the N-linked core pentasaccharide with direct applicability potential in a short time, with high yield and on a large gram scale.
- Li, Wei,Gao, Yu,Li, Qing,Li, Zhong-Jun
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supporting information
p. 4720 - 4727
(2018/07/06)
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- COMPOSITIONS AND METHODS FOR THE TREATMENT OF BACTERIAL INFECTIONS
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Compositions and methods for the treatment of bacterial infections include compounds containing dimers of cyclic heptapeptides conjugated to one or more monosaccharide or oligosaccharide moieties. In particular, compounds can be used in the treatment of bacterial infections caused by Gram-negative bacteria.
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- Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones
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A practical method for the selective and controlled oxidation of thioglycosides to corresponding glycosyl sulfoxides and sulfones is reported using urea–hydrogen peroxide (UHP). A wide range of glycosyl sulfoxides are selectively achieved using 1.5 equiv of UHP at 60 °C while corresponding sulfones are achieved using 2.5 equiv of UHP at 80 °C in acetic acid. Remarkably, oxidation susceptible olefin functional groups were found to be stable during the oxidation of sulfide.
- Singh, Adesh Kumar,Tiwari, Varsha,Mishra, Kunj Bihari,Gupta, Surabhi,Kandasamy, Jeyakumar
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supporting information
p. 1139 - 1144
(2017/06/20)
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- Practical synthesis of latent disarmed S-2-(2-propylthio)benzyl glycosides for interrupted Pummerer reaction mediated glycosylation
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Practical synthetic methods to latent disarmed S-2-(2-propylthio)benzyl (SPTB) glycosides for interrupted Pummerer reaction mediated glycosylation have been discovered. Among them, both coupling reaction of PTB-Cl with glycosyl thiols and BF3·OEt2 promoted reaction of peracylated glycosides with PTB-SH produced peracylated SPTB glycosides in large scales and with high efficiency.
- Xu, Yang,Zhang, Qian,Xiao, Ying,Wu, Pinru,Chen, Wei,Song, Zejin,Xiao, Xiong,Meng, Lingkui,Zeng, Jing,Wan, Qian
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supporting information
p. 2381 - 2384
(2017/05/29)
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- Design, synthesis and evaluation of cytotoxic properties of bisamino glucosylated antitumor ether lipids against cancer cells and cancer stem cells
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Glycosylated antitumor ether lipids (GAELs) are a class of amphiphilic antitumor agents that kill cancer cells by a non-apoptotic pathway. Previous studies have shown that 2-amino-2-deoxy-d-gluco-based GAELs such as α-GLN and β-GLN show greatly improved antitumor activity against epithelial cancer cells and stem cells. To further optimize the bioactivity, we prepared a series of diamino-d-gluco-based GAELs and their analogs, and screened them against a panel of human epithelial cancer cell lines and cancer stem cells. Most of the new GAEL analogs are more potent than chlorambucil, cisplatin and salinomycin. The most potent bisamine-based GAEL analogs 1, 2, 4 and 8 showed 2- to 3-fold enhanced cytotoxicity against various cancer cell lines when compared to β-GLN, indicating that the addition of a second amino group enhances the cytotoxic effect. The effect of the most active dicationic GAELs 1 and 4 on cancer stem cells isolated from breast (BT-474) and prostate (DU-145) cell lines revealed that the two GAELs inhibited the formation of tumor spheres and resulted in >95% loss of viability of the cancer stem cells at 5 μM. Activity of GAEL 1 against BT-474 cancer stem cells is superior to that of salinomycin.
- Ogunsina, Makanjuola,Samadder, Pranati,Idowu, Temilolu,Arthur, Gilbert,Schweizer, Frank
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supporting information
p. 2100 - 2110
(2016/11/18)
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- Cu(ClO4)2·6H2O catalyzed solvent free per-O-acetylation and sequential one-pot conversions of sugars to thioglycosides
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The solvent free per-O-acetylation of various reducing and non-reducing sugars has been carried out using stoichiometric amounts of acetic anhydride and copper(ii) perchlorate hexahydrate as the catalyst. The reactions with various reducing monosaccharides have also been followed by a one-pot sequential conversion to the corresponding thioglycosides in high yields. This journal is
- Chatterjee, Debnath,Paul, Abhijit,Rajkamal,Yadav, Somnath
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p. 29669 - 29674
(2015/05/20)
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- SYNTHETIC OLIGOGLUCOSAMINES FOR IMPROVEMENT OF PLANT GROWTH AND YIELD
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The disclosure provides formulations comprising synthetic oligoglucosamines and methods for improving plant growth and crop yield therewith. These formulations may be applied to propagating materials, including seeds and other regenerable plant parts, including cuttings, bulbs, rhizomes and tubers. They may also be applied to foliage, or soil either prior to or following planting of propagating materials. Such applications may be made alone or in combination with fungicides, insecticides, nematicides and other agricultural agents used to improve plant growth and crop yield.
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Page/Page column 45-46
(2015/10/05)
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- SYNTHETIC SALT COMPLEXES FOR IMPROVEMENT OF PLANT GROWTH AND YIELD
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The disclosure provides agricultural compositions comprising oligoglucosamine salt complexes and methods for improving plant growth and crop yield. These compositions may be applied to plant propagating materials, including seeds and other regenerable plant parts, including cuttings, bulbs, rhizomes and tubers. They may also be applied to foliage, or soil either prior to or following planting of plant propagating materials. Such applications may be made alone or in combination with fungicides, insecticides, nematicides and other agricultural agents used to improve plant growth and crop yield.
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Page/Page column 51; 52
(2015/10/05)
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- Synthesis of novel N-glycoside derivatives via CuSCN-catalyzed reactions and their SGLT2 inhibition activities
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A convenient approach to the synthesis of novel triazole-N-glycoside derivatives was developed via CuSCN-catalyzed click reaction and Ullmann-type coupling reaction for the first time. The SGLT2 inhibitory activities of these synthetic N-glycosides were evaluated, and some compounds showed moderate SGLT2 inhibition activities at 100 nM. The results could benefit the discovery of new SGLT2 inhibitors for the treatment of diabetes.
- Bai, Shao-Tao,Xiong, De-Cai,Niu, Youhong,Wu, Yan-Fen,Ye, Xin-Shan
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supporting information
p. 4909 - 4919
(2015/06/23)
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- DI- AND TRI-CATIONIC GLYCOSYLATED ANTITUMOR ETHER LIPIDS, L-GUCOSYLATED GAELS AND RHAMNOSE-LINKED GAELS AS CYTOTOXIC AGENTS AGAINST EPITHELIAL CANCER CELLS AND CANCER STEM CELLS
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Glycosylated Antitumor Ether Lipids (GAELs) kill cancer cells by a nonapoptotic pathway which is an attractive strategy to avoid resistance. To further optimize the antitumor effect, we prepared various analogs of di-, and tri-cationic GAEL analogs differing in the nature of the sugar (D-giucose or L-glucose), the anomeric linkage as well as position of the glycerolipid moiety. The di- and tri-cationic GAELs were synthesized and their in vitro anticancer properties were evaluated against drug resistant and aggressively growing cancer cell lines derived from human breast, prostate, pancreatic and ovarian cancers. The most potent dicationic GAEL analogs were also studied against cancer stem cells obtained from breast BT 474, prostate DU145 and ovarian A2780cp cell lines. Our results indicate that the number of positive charges, the position of the amino substituents and the nature of the sugar have significant effects on the anticancer activities of these compounds. The most active analog kill 50% of the cells at concentration range of 0.5-5μΜ and 90% of the cells at the concentration of 1-10μΜ depending on type of cancer cells.
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Page/Page column 37; 54; 55
(2016/02/10)
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- COMBINATORIAL LIBRARIES
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Synthetic mixtures comprising two or more synthetic oligoglucosamine based derivatives have been found to be useful in agricultural compositions for promoting seed germination. The disclosed synthetic mixtures may be applied to plant propagating materials, including seeds and other regenerable plant parts, including cuttings, bulbs, rhizomes and tubers. They may also be applied to foliage, or soil either prior to or following planting of plant propagating materials. Such applications may be made alone or in combination with fungicides, insecticides, nematicides and other agricultural agents used to improve plant growth and crop yield.
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Paragraph 168
(2015/11/02)
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- USE OF GLUCOSAMINE AMIDES AS PLANT GROWTH AND YIELD ENHANCERS
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The invention provides compositions and methods for improving plant growth and crop yield. More specifically, the present invention relates to compositions comprising the glucosamine amide N-palmitoleyl-D-glucosamine (NPG) and other substituted glucosamine compounds. NPG and its substituted analogs may be applied to plant propagating materials, including seeds and other regenerable plant parts, including cuttings, bulbs, rhizomes and tubers. NPG and its analogs may also be applied to foliage or soil either prior to or following planting of plant propagating materials. Such applications may be made alone or in combination with fungicides, insecticides, nematicides and other agricultural agents used to improve plant growth and crop yield. NPG and its analogs can improve the agronomic performance of a variety of crops including barley, canola, corn, potato, soybean and wheat.
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Page/Page column 26
(2014/05/24)
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- Synthetic routes toward the trisaccharide related to the lipopolysaccharide of Burkholderia sp. HKI-402 (B4)
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A stepwise and a three component one-pot sequential glycosylation reaction has been used for the synthesis of trisaccharide related to the LPS of Burkholderia sp. HKI-402 (B4) employing trichloroacetimidate and thio donors. This journal is
- Basu, Nabamita,Mukherjee, Mana Mohan,Ghosh, Rina
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p. 54084 - 54090
(2015/01/16)
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- CARBOHYDRATE-MODIFIED GLYCOPROTEINS AND USES THEREOF
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The present invention provides immunogenic compounds which stimulate immune responses in a subject. The present invention provides compositions comprising an isolated glycoprotein antigen covalently bound at pre-existing carbohydrate residues present on the glycoprotein to a carbohydrate epitope. The present invention also provides a method to induce an immune response in a subject comprising administering the compounds of the invention. The present invention further provides methods of making the compounds of the invention and methods of using the compounds of the invention to stimulate immune responses to infectious disease agents and tumors.
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- Synthesis of oligonucleotides with glucosamine at the 3′-position and evaluation of their biological activity
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Short interfering RNA (siRNA) has been proven to be an utilizable tool for post-transcriptional gene silencing research. In this study, we designed and synthesized two glucosamine analogues and tried to modify the siRNA using these two glucosamine analogues at the 3′-overhang region of siRNAs to improve the nuclease resistance and to overcome some other weak points. The siRNAs modified with glucosamine analogues had almost no effect of the thermal stability and showed strong resistance to nuclease degradation. Some of them kept the same gene silencing activity level as unmodified siRNA.
- Luo, Xiong,Sugiura, Takahiro,Nakashima, Remi,Kitamura, Yoshiaki,Kitade, Yukio
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supporting information
p. 4157 - 4161
(2013/07/25)
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- 'Naked' and hydrated conformers of the conserved core pentasaccharide of N-linked glycoproteins and its building blocks
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N-glycosylation of eukaryotic proteins is widespread and vital to survival. The pentasaccharide unit -Man3GlcNAc2- lies at the protein-junction core of all oligosaccharides attached to asparagine side chains during this process. Although its absolute conservation implies an indispensable role, associated perhaps with its structure, its unbiased conformation and the potential modulating role of solvation are unknown; both have now been explored through a combination of synthesis, laser spectroscopy, and computation. The proximal -GlcNAc-GlcNAc- unit acts as a rigid rod, while the central, and unusual, -Man-β-1,4-GlcNAc- linkage is more flexible and is modulated by the distal Man-α-1,3- and Man-α-1,6- branching units. Solvation stiffens the 'rod' but leaves the distal residues flexible, through a β-Man pivot, ensuring anchored projection from the protein shell while allowing flexible interaction of the distal portion of N-glycosylation with bulk water and biomolecular assemblies.
- Barry, Conor S.,Cocinero, Emilio J.,Carcabal, Pierre,Gamblin, David P.,Stanca-Kaposta, E. Cristina,Remmert, Sarah M.,Fernandez-Alonso, Maria C.,Rudic, Svemir,Simons, John P.,Davis, Benjamin G.
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supporting information
p. 16895 - 16903
(2013/12/04)
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- GLYCOSYLATED ANTITUMOR ETHER LIPIDS AS NOVEL CANCER STEM CELL CYTOTOXIC AGENTS
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Glycosylated antitumor ether lipids (GAELs) are effective cytotoxic agents against cancer stem cells. Furthermore, combining GAELs which kill cells by a caspase-independent pathway with agents that kill cells by apoptosis will lead to elimination of the differentiated tumor cells and the undifferentiated cancer stem cells leading to an elimination of the tumor and preventing recurrence.
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Page/Page column 41
(2013/08/28)
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- Synthesis and immunological characterization of modified hyaluronic acid hexasaccharide conjugates
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The synthesis of a tetanus toxoid (TT)-conjugate of a hyaluronic acid (HA) hexasaccharide is described. The compound was intended for use in monitoring HA levels as a disease marker and as a potential vaccine against Group A Streptococcus (GAS) infections. We also report the synthesis of a chemically modified HA-hexasaccharide-TT conjugate in which the N-acetyl moiety of the N-acetyl-d-glucosamine residue is replaced with an N-propionyl unit in order to enhance immunogenicity. The oligosaccharides are synthesized in a convergent manner. The TT-conjugate syntheses rely on the reaction of the amines on the 6-aminohexyl aglycon of the hexasaccharides with diethyl squarate to give the monoethyl squarate adducts. Subsequent reactions with lysine ε-amino groups on TT then give the glycoconjugates containing an average of 8 hexasaccharide haptens per TT molecule. Immunological studies in mice show very similar antibody responses with both conjugates, suggesting that the N-acetyl groups of the glucosaminyl residues of the HA-hexasaccharide are not a critical part of the epitope recognized by the anti-HA polyclonal immune response. Furthermore, it would appear that the N-acyl moieties are not in close contact with the amino acid residues of the antibody combining sites.
- Gu, Guofeng,Adabala, Pal John Pal,Szczepina, Monica G.,Borrelli, Silvia,Pinto, B. Mario
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p. 8004 - 8019
(2013/09/12)
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- A facile and efficient method for the one-pot synthesis of per-O-acetylated thioglycosides from unprotected sugars
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An efficient, convenient protocol for the preparation of per-O-acetylated p-tolylthio glycosides is described. Treatment of various unprotected sugars, including 2-deoxy-2-amino sugars, sialic acid, lactose, and maltose, with acetic anhydride using SnCl4 as a catalyst, and subsequently with p-tolylthiol, furnished the corresponding thioglycosides in 71%-90% yield under solvent-free conditions.
- Yan, Shiqiang,Ding, Ning,Zhang, Wei,Wang, Peng,Li, Yingxia,Li, Ming
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p. 571 - 583
(2012/10/30)
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- Combining weak affinity chromatography, NMR spectroscopy and molecular simulations in carbohydrate-lysozyme interaction studies
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By examining the interactions between the protein hen egg-white lysozyme (HEWL) and commercially available and chemically synthesized carbohydrate ligands using a combination of weak affinity chromatography (WAC), NMR spectroscopy and molecular simulations, we report on new affinity data as well as a detailed binding model for the HEWL protein. The equilibrium dissociation constants of the ligands were obtained by WAC but also by NMR spectroscopy, which agreed well. The structures of two HEWL-disaccharide complexes in solution were deduced by NMR spectroscopy using 1H saturation transfer difference (STD) effects and transferred 1H,1H-NOESY experiments, relaxation-matrix calculations, molecular docking and molecular dynamics simulations. In solution the two disaccharides β-d-Galp-(1→4) -β-d-GlcpNAc-OMe and β-d-GlcpNAc-(1→4)-β-d-GlcpNAc-OMe bind to the B and C sites of HEWL in a syn-conformation at the glycosidic linkage between the two sugar residues. Intermolecular hydrogen bonding and CH/π-interactions form the basis of the protein-ligand complexes in a way characteristic of carbohydrate-protein interactions. Molecular dynamics simulations with explicit water molecules of both the apo-form of the protein and a ligand-protein complex showed structural change compared to a crystal structure of the protein. The flexibility of HEWL as indicated by a residue-based root-mean-square deviation analysis indicated similarities overall, with some residue specific differences, inter alia, for Arg61 that is situated prior to a flexible loop. The Arg61 flexibility was notably larger in the ligand-complexed form of HEWL. N,N′-Diacetylchitobiose has previously been observed to bind to HEWL at the B and C sites in water solution based on 1H NMR chemical shift changes in the protein whereas the disaccharide binds at either the B and C sites or the C and D sites in different crystal complexes. The present study thus highlights that protein-ligand complexes may vary notably between the solution and solid states, underscoring the importance of targeting the pertinent binding site(s) for inhibition of protein activity and the advantages of combining different techniques in a screening process. The Royal Society of Chemistry 2012.
- Landstroem, Jens,Bergstroem, Maria,Hamark, Christoffer,Ohlson, Sten,Widmalm, Goeran
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supporting information; experimental part
p. 3019 - 3032
(2012/05/07)
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- Solid-phase synthesis of 2-aminoethyl glucosamine sulfoforms
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Mono- and disaccharides of sulfonated glucosamines (GlcN sulfoforms) conjugated to 2-aminoethyl linkers were generated by solid-phase synthesis. Orthogonally protected intermediates were tethered onto tritylated polystyrene resin beads, subjected to amodular sequence of deprotection and sulfonation steps, then cleaved from solid support without degradation of N- or O-sulfate esters using solvolytic conditions, and finally purified by reverse-phase HPLC to afford the title compounds. Copyright Taylor & Francis Group, LLC.
- Liu, Runhui,Wei, Alexander
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experimental part
p. 384 - 419
(2012/08/07)
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- Synthesis and selective anticancer activity of steroidal glycoconjugates
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The synthesis of glucosamine derivatives of the steroidal sapogenins diosgenin and hecogenin using the N-phthaloyl protected trichloroacetimidate of d-glucosamine as donor and TMSOTf as promoter is reported. The corresponding glycoconjugates were transformed into their acetamido derivatives and the hydrochloride salt (from diosgenin) and tested against HeLa, CaSki, and ViBo cervicouterine cancer cells. These compounds showed low cytotoxicity values on tumor cells and human lymphocytes, indicating that the main cell death process is presumably not necrosis. Significantly, the antiproliferative activity of these compounds on tumor cells did not affect the proliferative potential of peripheral blood lymphocytes.
- Fernandez-Herrera, Maria A.,Lopez-Munoz, Hugo,Hernandez-Vazquez, Jose M.V.,Sanchez-Sanchez, Luis,Escobar-Sanchez, Maria L.,Pinto, B. Mario,Sandoval-Ramirez, Jesus
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experimental part
p. 721 - 727
(2012/09/21)
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- SYNTHETIC OLIGOSACCHARIDES FOR STAPHYLOCOCCUS VACCINE
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The present invention synthetic oligo-β-(1→6)-glucosamine structures and a methodology which essentially allows for the synthesis of any oligo-β-(1→6)-glucosamine species having a definite number of monosaccharide units, including a set pattern of acetylated and non- acetylated residues. The invention further provides antibodies to these synthetic oligo-β-(1→6)-glucosamines as well as compositions thereof and methods for treating and preventing infections caused by bacteria expressing poly-β-(1→6)-glucosamines, such as Staphylococcus aureus.
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Page/Page column 40-41
(2012/11/07)
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- An efficient synthesis of the protected carbohydrate moiety of Brasilicardin A
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A synthesis of the protected carbohydrate moiety 2 of Brasilicardin A starting from l-rhamnose and d-glucosamine is described. The disaccharide was synthesized using a TMSOTf-mediated glycosylation of the 2-phthalimido-2- deoxyglucose donor 5 and the 3-hydroxyl group of the protected l-rhamnose derivative 4, which already bears the 3-hydroxybenzoate unit. The imidate 2 was coupled via TMSOTf-mediated glycosidation with cholesterol as a model aglycone followed by the selective cleavage of all the acetate groups to give the Brasilicardin A analogue 16.
- Jung, Michael E.,Koch, Pierre
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supporting information; experimental part
p. 3710 - 3713
(2011/09/14)
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- Random-coil:α-helix equilibria as a reporter for the Lewis X-LewisX interaction
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Probing weak interactions: A peptide random-coil:α-helix equilibrium has been used to identify a weak carbohydrate-carbohydrate interaction (CCI). Glucose and lactose destabilized the helical conformer while LewisX trisaccharide led to increased helicity. Though small, the trend observed indicates that this peptide reporter can detect a single CCI in isolation. Copyright
- Altamore, Timothy M.,Fernandez-Garcia, Christian,Gordon, Andrew H.,Huebscher, Tina,Promsawan, Netnapa,Ryadnov, Maxim G.,Doig, Andrew J.,Woolfson, Derek N.,Gallagher, Timothy
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supporting information; scheme or table
p. 11167 - 11171
(2012/02/02)
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- Design and synthesis of novel cell wall inhibitors of Mycobacterium tuberculosis GlmM and GlmU
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GlmM and GlmU are key enzymes in the biosynthesis of UDP-N-acetyl-D- glucosamine (UDP-GlcNAc), an essential precursor of peptidoglycan and the rhamnose-GlcNAc linker region in the mycobacterial cell wall. These enzymes are involved in the conversion of two important precursors of UDP-GlcNAc, glucosamine-6-phosphate (GlcN-6-P) and glucosamine-1-phosphate (GlcN-1-P). GlmM converts GlcN-6-P to GlcN-1-P, GlmU is a bifunctional enzyme, whereby GlmU converts GlcN-1-P to GlcNAc-1-P and then catalyzes the formation of UDP-GlcNAc from GlcNAc-1-P and uridine triphosphate. In the present study, methyl 2-amino-2-deoxyl-α-D-glucopyranoside 6-phosphate (1α), methyl 2-amino-2- deoxyl-β-D-glucopyranoside 6-phosphate (1β), two analogs of GlcN-6-P, were synthesized as GlmM inhibitors; 2-azido-2-deoxy-α-D- glucopyranosyl phosphate (2) and 2-amino-2,3-dideoxy-3-fluoro-α- Dglucopyranosyl phosphate (3), analogs of GlcN-1-P, were synthesized firstly as GlmU inhibitors. Compounds 1α, 1β, 2, and 3 as possible inhibitors of mycobacterial GlmM and GlmU are reported herein. Compound 3 showed promising inhibitory activities against GlmU, whereas 1α, 1β and 2 were inactive against GlmM and GlmU even at high concentrations.
- Li, Yongmeng,Zhou, Yan,Mac, Yufang,Li, Xuebing
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p. 1714 - 1720
(2011/12/02)
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- SYNTHETIC OLIGOSACCHARIDES FOR STAPHYLOCCOCUS VACCINE
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The present invention synthetic oligo-β-(1→6)-glucosamine structures and a methodology which essentially allows for the synthesis of any oligo-β-(1→6)- glucosamine species having a definite number of monosaccharide units, including a set pattern of acetylated and non-acetylated residues. The invention further provides antibodies to these synthetic oligo-β-(1→6)-glucosamines as well as compositions thereof and methods for treating and preventing infections caused by bacteria expressing poly-β-(1→6)-glucosamines, such as Staphylococcus aureus.
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Page/Page column 230-231
(2011/11/06)
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- Comparing the use of 2-methylenenapthyl, 4-methoxybenzyl, 3,4-dimethoxybenzyl and 2,4,6-trimethoxybenzyl as N-H protecting groups for p-tolyl 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-1-thio-β-d-glucosides
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A hurdle in glycosylation reactions of 2-acetamido glycosyl donors is the formation of a stable and unreactive oxazoline that decreases the yield of these reactions significantly. As an effort to prevent oxazoline formation during glycosylation reactions,
- Sarkar, Sourav,Sucheck, Steven J.
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experimental part
p. 393 - 400
(2011/04/15)
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- Synthesis of a monophosphoryl lipid A derivative and its conjugation to a modified form of a tumor-associated carbohydrate antigen GM3
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An efficient synthesis of a derivative of monophosphoryl lipid A suitable for coupling to various structures for the construction of glycoconjugate vaccines and its conjugation with an N-modified form of the tumor-associated antigen GM3 is presented.
- Wang, Qianli,Xue, Jie,Guo, Zhongwu
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supporting information; experimental part
p. 5536 - 5537
(2010/01/31)
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- Toward fully synthetic homogeneous β -human Follicle-Stimulating hormone (β -hFSH) with a biantennary N-linked dodecasaccharide. synthesis of β -hFSH with chitobiose units at the natural linkage sites
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A highly convergent synthesis of the sialic acid-rich biantennary N-linked glycan found in human glycoprotein hormones and its use in the synthesis of a fragment derived from the β -domain of human Follicle-Stimulating Hormone (hFSH) are described. The synthesis highlights the use of the Sinay radical glycosidation protocol for the simultaneous installation of both biantennary side-chains of the dodecasaccharide as well as the use of glycal chemistry to construct the tetrasaccharide core in an efficient manner. The synthetic glycan was used to prepare the glycosylated 20-27aa domain of the β -subunit of hFSH under a Lansbury aspartylation protocol. The proposed strategy for incorporating the prepared N-linked dodecasaccharide-containing 20-27aa domain into β -hFSH subunit was validated in the context of a model system, providing protected β -hFSH subunit functionalized with chitobiose at positions 7 and24.
- Nagorny, Pavel,Fasching, Bernhard,Li, Xuechen,Chen, Gong,Aussedat, Baptiste,Danishefsky, Samuel J.
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supporting information; experimental part
p. 5792 - 5799
(2009/09/24)
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- Synthetic modification of β-sitosterol with 2-amino-1,3,4,6-tetra-O- hydroxy-2-deoxy-β-D-glucopyranose hydrochloride
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Coupling of β-sitosterol with glucosamine yields glucoside which has enhanced bioavailability due to number of polar groups present in the glucoside and is expected to possess enhanced anti-arthritic activity due to synergistic effects of both anti-arthritic drugs.
- Grover, Parul,Singh, Jitender,Dhar,Mehta, Lovekesh
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experimental part
p. 1112 - 1114
(2011/06/26)
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- Preparation of Thiosugars and Their Use
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A process for the preparation of a thiosaccharide represented by Saccharide-S-H wherein Saccharide comprises at least 4 sugar units, comprises subjecting a corresponding compound of the formula (P)Saccharide-S-(P) wherein (P) represents an O- or S-protecting group(s), to Birch reduction.
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Page/Page column 2; 19
(2009/07/18)
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- Sweets for catalysis - Facile optimisation of carbohydrate-based bis(oxazoline) ligands
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A new type of carbohydrate-based bis(oxazoline) ligands was prepared from inexpensive D-glucosamine and tested in asymmetric cyclopropanation reactions. For optimisation, modified ligands with 3-O substituents of varying size and electronic properties were prepared as well as a 3-OH unprotected and a perpivaloylated derivative. All new ligands were tested in asymmetric cyclopropanation, revealing a strong dependence of enantioselectivity on steric demand and electronic properties of the 3-O residue. Also, a significant influence of the pyranose conformation, which is determined by the presence or absence of the cyclic acetal group, was observed. Thus, it was easily possible to tune the new carbohydrate bis(oxazoline) ligands to a given reaction.
- Minuth, Tobias,Irmak, Mustafa,Groschner, Annika,Lehnert, Tobias,Boysen, Mike M. K.
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experimental part
p. 997 - 1008
(2009/07/19)
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