Glycosylation efficiencies on different solid supports using a hydrogenolysis-labile linker

• Mayeul Collot,
• Steffen Eller,
• Markus Weishaupt and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 97–105, doi:10.3762/bjoc.9.13

• cleavage efficiencies on these functionalized solid supports were investigated, and restrictions for the choice of solid support for oligosaccharide synthesis were found. Keywords: glycosylation; hydrogenolysis; linkers; oligosaccharides; resins; solid-phase synthesis; Findings Since Bruce Merrifield

• oligosaccharides [4]. Solid-phase synthesis is performed on insoluble supports that are functionalized with a linker that connects the growing molecule with the resin (Scheme 1). Once the target molecule has been assembled, it is cleaved from the solid support. The solid-phase paradigm allows for the use of excess

• ], the need for synthetic tools has prompted synthetic carbohydrate chemists to develop methods for the accelerated synthesis of all types of glycans [9][10][11][12][13][14][15][16][17][18][19]. Automated synthesis of oligosaccharides is beginning to provide molecules for biological evaluation [20][21

Removal of benzylidene acetal and benzyl ether in carbohydrate derivatives using triethylsilane and Pd/C

• Abhishek Santra,
• Tamashree Ghosh and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2013, 9, 74–78, doi:10.3762/bjoc.9.9

• hydrogenation; triethylsilane; Introduction Functionalization of carbohydrate intermediates is essential for their assembly towards the synthesis of complex oligosaccharides [1][2][3][4][5][6][7][8][9]. Benzylidene acetal is a frequently used protecting group for the simultaneous protection of 1,2- and 1,3

Peptoids and polyamines going sweet: Modular synthesis of glycosylated peptoids and polyamines using click chemistry

• Daniel Fürniss,
• Timo Mack,
• Frank Hahn,
• Sidonie B. L. Vollrath,
• Katarzyna Koroniak,
• Ute Schepers and
• Stefan Bräse

Beilstein J. Org. Chem. 2013, 9, 56–63, doi:10.3762/bjoc.9.7

• azide alkyne cycloadditions. In addition, the up-scaling of some particular azide-modified sugars is described. Keywords: click chemistry; glycans; peptoids; polyalkynes; polyamines; solid-phase chemistry; Introduction To date, oligosaccharides have gained more and more interest as potential drugs in

• the treatment of a variety of diseases. However, the rendering of nucleic acids and oligosaccharides as therapeutically active substances often requires a derivatization or a chemical coupling reaction that permits the selective and simple formation of covalent adducts. Some modifications permit the

• functional structures. Likewise, the coupling reaction should be permitted in hydrophilic solvents such as water or DMSO, since both unprotected nucleic acids and oligosaccharides, as well as many other biomacromolecules, prefer a hydrophilic reaction environment. With the advent of mild and biocompatible

Theoretical study on β-cyclodextrin inclusion complexes with propiconazole and protonated propiconazole

• Adrian Fifere,
• Narcisa Marangoci,
• Stelian Maier,
• Adina Coroaba,
• Dan Maftei and
• Mariana Pinteala

Beilstein J. Org. Chem. 2012, 8, 2191–2201, doi:10.3762/bjoc.8.247

• compared to unmodified PP. The inclusion compound based on β-cyclodextrin (β-CD) and PPH+ (further abbreviated as β-CD/PPH+) was preliminarily investigated in vitro, and its antifungal activity was reported [4]. Cyclodextrins (CDs) are macrocyclic oligosaccharides consisting of six to twelve glucopyranose

Synthesis of a derivative of α-D-Glcp(1->2)-D-Galf suitable for further glycosylation and of α-D-Glcp(1->2)-D-Gal, a disaccharide fragment obtained from varianose

• Carla Marino,
• Carlos Lima,
• Karina Mariño and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2012, 8, 2142–2148, doi:10.3762/bjoc.8.241

• monitor the natural disaccharide released from varianose by mild acid degradation. The synthesis, performed by the glycosylaldonolactone approach, involved a glucosylgalactofuranose derivative, suitable for the synthesis of higher oligosaccharides with an internal D-Galf. Keywords: α-D-galactofuranose

• )Galf and β-Galf(1→6)Galf [12][13][14]. Synthetic oligosaccharides have been used to characterize these GalfTs and it was demonstrated that a single active site in GalfT2 is responsible for both activities [15]. The crystal structures of both, free and UDP-bound GalfT2 have been recently determined [16

• a good model for studies on the GlfTα. The constitutive oligosaccharides could be used as substrates or as standards for the identification of the products. A pentasaccharide fragment containing both, α and β-galactofuranosyl residues was synthesized by Bay and Lowary [18]. The two possible

Acylsulfonamide safety-catch linker: promise and limitations for solid–phase oligosaccharide synthesis

• Jian Yin,
• Steffen Eller,
• Mayeul Collot and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2012, 8, 2067–2071, doi:10.3762/bjoc.8.232

• cleavage products revealed shortcomings for oligosaccharide synthesis. Keywords: glycosaminoglycans (GAGs); glycosylation; resins; safety-catch linker; solid-phase synthesis; Findings Solid-phase oligosaccharide synthesis [1][2] has been automated [3][4][5] to rapidly assemble complex oligosaccharides

• linker 1 [13][14] (Figure 1) has been developed, which can be readily cleaved from the resin by basic methanolysis. The released chromophore-containing part, such as aromatic benzyl ether protecting groups, facilitates the purification of the synthetic oligosaccharides by HPLC. Final deprotection of the

Convergent synthesis of the tetrasaccharide repeating unit of the cell wall lipopolysaccharide of Escherichia coli O40

• Abhijit Sau and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2012, 8, 2053–2059, doi:10.3762/bjoc.8.230

• ]. In order to evaluate the therapeutic efficacy of the glycoconjugate derivatives it is essential to have a significant quantity of oligosaccharides, which is difficult to isolate from natural sources. Therefore, the development of a chemical synthetic strategy for the synthesis of the oligosaccharides

Self-assembled organic–inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles

• Ângelo M. L. Denadai,
• Frederico B. De Sousa,
• Joel J. Passos,
• Fernando C. Guatimosim,
• Kirla D. Barbosa,
• Ana E. Burgos,
• Fernando Castro de Oliveira,
• Jeann C. da Silva,
• Bernardo R. A. Neves,
• Nelcy D. S. Mohallem and
• Rubén D. Sinisterra

Beilstein J. Org. Chem. 2012, 8, 1867–1876, doi:10.3762/bjoc.8.215

• (CDs) can be associated with the inorganic matrix as an interesting strategy, since these macromolecules have been used for several devices with different properties, from light-responsive matrices to molecular recognition materials [12][13]. CDs are oligosaccharides commonly formed by six, seven or

Molecular solubilization of fullerene C₆₀ in water by γ-cyclodextrin thioethers

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2012, 8, 1644–1651, doi:10.3762/bjoc.8.188

• ][22]. CDs are cyclic oligosaccharides consisting of six, seven, eight or more glucose subunits connected through α-1,4 glycosidic linkages, called α-, β-, and γ-CD, respectively. CD molecules resemble truncated cones comprising a hydrophilic outer surface and a relatively hydrophobic cavity [23][24

Automated synthesis of sialylated oligosaccharides

• Davide Esposito,
• Mattan Hurevich,
• Bastien Castagner,
• Cheng-Chung Wang and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2012, 8, 1601–1609, doi:10.3762/bjoc.8.183

• , which have been extensively studied [2]. The distinctive structure of Sia confers special properties to membrane oligosaccharides [3] resulting in sialosides having exceptional biological significance. Rapid access to synthetic sialylated glycans would contribute greatly to the biological studies on

• this important class of molecules. The automated synthesis of oligosaccharides has been significantly improved since the first report in 2001 [4]. Currently, the platform enables the rapid assembly of complex oligosaccharides and accommodates the most commonly employed glycosylation reactions [5][6][7

• building blocks proved successful for the synthesis of representative Sia-containing oligosaccharides ready for biological evaluation. Results and Discussion Building-blocks preparation Many sialylation strategies utilize building blocks that require multistep syntheses [10]. In contrast, solid-phase

Mannose-decorated cyclodextrin vesicles: The interplay of multivalency and surface density in lectin–carbohydrate recognition

• Ulrike Kauscher and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2012, 8, 1543–1551, doi:10.3762/bjoc.8.175

• role of oligosaccharides on cell surfaces is the fact that human blood types (A, B, AB and 0) are solely determined by minor changes in the composition of the erythrocyte glycocalyx. Additionally, many biological mechanisms are mediated by multivalent recognition of carbohydrates. For example, lectins

• to ConA and, hence, is able to mediate fast agglutination at low overall concentration as well as low surface coverage. These findings should further the understanding of the complex and dynamic interactions of oligosaccharides on cell surfaces. Experimental Materials: Throughout this work, chemicals

Superstructures with cyclodextrins: Chemistry and applications

• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 1303–1304, doi:10.3762/bjoc.8.148

• Helmut Ritter Institute of Organic Chemistry and Macromolecular Chemistry II, Heinrich-Heine-University of Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany 10.3762/bjoc.8.148 Keywords: cyclodextrins; superstructures; Cyclodextrins (CDs) are cyclic oligosaccharides consisting of 6 (α

The use of glycoinformatics in glycochemistry

• Thomas Lütteke

Beilstein J. Org. Chem. 2012, 8, 915–929, doi:10.3762/bjoc.8.104

• Chemical Identifier) codes, and 3D structural information in mol2 format. However, no carbohydrate-specific search options are available. This can make it difficult to locate entries in ChEBI or PubChem especially for oligosaccharides. Introducing cross-links between carbohydrate-specific databases and the

• structures stored in the databases. An analysis of mammalian carbohydrate structures present in Glycosciences.DB, for example, revealed that this data set contained 3299 oligosaccharides, which are part of N-glycans, O-glycans or glycolipids from 38 mammalian species. Only ten different monosaccharides were

• found in this data set [66]. However, different anomeric configurations and some substitutions, such as sulfate groups, were ignored, and no distinction was made between N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc). The large number of different oligosaccharides that are

Synthetic glycopeptides and glycoproteins with applications in biological research

• Ulrika Westerlind

Beilstein J. Org. Chem. 2012, 8, 804–818, doi:10.3762/bjoc.8.90

• - or oligosaccharides. The glycoprotein saccharides contribute physiochemical properties, influencing protein conformation or increasing stability against proteolytic activity. With their unique structural diversity and complexity, carbohydrates attached on proteins or lipids are involved in numerous

• glycopeptide/glycoprotein synthesis, Endo-A specific for high-mannose glycans and Endo-M operating on both high-mannose and complex type N-glycans [81][82][83]. These enzymes can, in contrast to glycosyltransferases, by means of a one-step reaction attach large oligosaccharides to a GlcNAc polypeptide. Until

An easily accessible sulfated saccharide mimetic inhibits in vitro human tumor cell adhesion and angiogenesis of vascular endothelial cells

• Grazia Marano,
• Claas Gronewold,
• Martin Frank,
• Anette Merling,
• Christian Kliem,
• Sandra Sauer,
• Manfred Wiessler,
• Eva Frei and
• Reinhard Schwartz-Albiez

Beilstein J. Org. Chem. 2012, 8, 787–803, doi:10.3762/bjoc.8.89

• Kao Germany GmbH, Pfungstädter Str. 92–100, 64297 Darmstadt/Eberstadt, Germany, Biognos AB, Generatorsgatan 1, 41705 Goeteborg, Sweden 10.3762/bjoc.8.89 Abstract Oligosaccharides aberrantly expressed on tumor cells influence processes such as cell adhesion and modulation of the cell’s

• among cells are mediated by binding of proteins such as lectins to oligosaccharides. Upon progression to higher malignancy, the glycosylation patterns of glycoproteins and glycosphingolipids on tumor cell surfaces undergo several alterations [6]. These changes are closely associated with distinct

• development not only of new tools for tumor diagnosis and monitoring but also in the design of new anticancer drugs [8]. Attempts have been made to mount an immune response against tumor oligosaccharides by carbohydrate vaccines [9] and also to inhibit adhesive processes, such as the interaction between

Triterpenoid saponins from the roots of Acanthophyllum gypsophiloides Regel

• Elena A. Khatuntseva,
• Vladimir M. Men’shov,
• Alexander S. Shashkov,
• Yury E. Tsvetkov,
• Rodion N. Stepanenko,
• Raymonda Ya. Vlasenko,
• Elvira E. Shults,
• Genrikh A. Tolstikov,
• Tatjana G. Tolstikova,
• Dimitri S. Baev,
• Vasiliy A. Kaledin,
• Nelli A. Popova,
• Valeriy P. Nikolin,
• Pavel P. Laktionov,
• Anna V. Cherepanova,
• Tatiana V. Kulakovskaya,
• Ekaterina V. Kulakovskaya and
• Nikolay E. Nifantiev

Beilstein J. Org. Chem. 2012, 8, 763–775, doi:10.3762/bjoc.8.87

• triterpene aglycon and showed the positions of the substitutions within the oligosaccharide fragments (Table 1 and Table 2). The ROESY spectra (identical for compounds 1 and 2) disclosed the sequence of the residues in two oligosaccharides and their location at the C-3 and C-28 of the aglycon. Thus, the

• (Figure 4). The other inter-residue correlation peaks were in agreement with the structure of oligosaccharides established from analysis of the ROESY spectra. Characteristic chemical shifts in the 13C NMR spectrum of 2 (δC 85.4 ppm for C-3 and δC 176.4 ppm for C-28 of the aglycon) evidence the

Chemo-enzymatic modification of poly-N-acetyllactosamine (LacNAc) oligomers and N,N-diacetyllactosamine (LacDiNAc) based on galactose oxidase treatment

• Christiane E. Kupper,
• Ruben R. Rosencrantz,
• Birgit Henßen,
• Helena Pelantová,
• Stephan Thönes,
• Anna Drozdová,
• Vladimir Křen and
• Lothar Elling

Beilstein J. Org. Chem. 2012, 8, 712–725, doi:10.3762/bjoc.8.80

• . Results and Discussion Evaluation of Gal- and GalNAc terminated poly-LacNAc oligomers as substrates of galactose oxidase The activity of galactose oxidase from Dactylium dendroides with LacNAc 1a, Gal-terminated poly-LacNAc oligosaccharides 1b–d and LacDiNAc 2 (Scheme 1) was investigated by a photometric

• oligosaccharides, either by photometric or by HPLC analysis, even after long reaction times (data not shown). This confirms that galactose oxidase accepts only terminal galactose residues of poly-LacNAc glycans, as previously concluded for the oxidation of raffinose and plant arabinogalactan polysaccharides [36

• -antigens (β1,6-branched poly-LacNAc) [58][59]. The I-antigen structures have so far been synthesised by chemical routes [60][61]. A similar coupling of oligosaccharides has already been shown by Rodriguez et al. on peptides, but no branching site in the glycans was introduced in their study [35]. In

Sonogashira–Hagihara reactions of halogenated glycals

• Dennis C. Koester and
• Daniel B. Werz

Beilstein J. Org. Chem. 2012, 8, 675–682, doi:10.3762/bjoc.8.75

• ][3][4]. Many different monosaccharide units and the large variety of possibilities to link two subunits result in an immense variety of highly complex biomolecules [5][6][7]. In order to mimic certain subunits of oligosaccharides, e.g., for the inhibition of glycosidases or glycosyltransferases

2-Allylphenyl glycosides as complementary building blocks for oligosaccharide and glycoconjugate synthesis

• Hemali D. Premathilake and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2012, 8, 597–605, doi:10.3762/bjoc.8.66

• efficient oligosaccharide assembly. Keywords: carbohydrates; glycosylation; leaving group; oligosaccharides; orthogonal strategy; selective activation; Introduction Current knowledge about the key roles of carbohydrates is still limited. However, thanks to the explosive growth of the field of glycobiology

• particularly stimulating for major scientific efforts in the field of modern glycosciences. The traditional chemical synthesis of oligosaccharides is lengthy because it involves multiple manipulations of protecting and/or leaving groups between glycosylation steps [5]. Many advanced strategies that shorten the

• give streamlined access to oligosaccharides (Scheme 1). Yet, the orthogonal strategy remains underdeveloped, with too few examples to become universally applicable. Only Ogawa’s S-phenyl (SPh) versus fluoride [9][10][13] and our thioimidate-based approaches [14][15][16] are known. A very promising

Enantioselective supramolecular devices in the gas phase. Resorcin[4]arene as a model system

• Caterina Fraschetti,
• Matthias C. Letzel,
• Antonello Filippi,
• Maurizio Speranza and
• Jochen Mattay

Beilstein J. Org. Chem. 2012, 8, 539–550, doi:10.3762/bjoc.8.62

• , even in the gas phase. The most recent advances in this field include several gas-phase investigations: (i) The size and structure selectivity of tetraethyl and tetraphenyl resorcin[4]arenes in the recognition of mono, di-, and oligosaccharides by electrospray coupled with Fourier transform ion

Electrochemical generation of 2,3-oxazolidinone glycosyl triflates as an intermediate for stereoselective glycosylation

• Toshiki Nokami,
• Akito Shibuya,
• Yoshihiro Saigusa,
• Shino Manabe,
• Yukishige Ito and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2012, 8, 456–460, doi:10.3762/bjoc.8.52

• Stereoselective formation of glycosidic linkages is the key issue in oligosaccharide synthesis, because both 1,2-trans and 1,2-cis aminoglycosides are ubiquitous in biologically active oligosaccharides [1][2][3][4][5]. The 1,2-trans aminoglycosides, which are found in Nod factor [1] and lipid A [2], can be easily

Synthesis of fluorinated maltose derivatives for monitoring protein interaction by ¹⁹F NMR

• Michaela Braitsch,
• Hanspeter Kählig,
• Georg Kontaxis,
• Michael Fischer,
• Toshinari Kawada,
• Robert Konrat and
• Walther Schmid

Beilstein J. Org. Chem. 2012, 8, 448–455, doi:10.3762/bjoc.8.51

• involved in active transport processes of small molecules into gram-negative bacteria through their function as an initial high-affinity binding component; furthermore, these proteins participate as sensors for signaling during chemotaxis [14]. MBP binds maltodextrin and linear oligosaccharides of up to

• addition of 0.04 equiv of maltose. Similar results were obtained for the malto-oligosaccharides, maltotriose and maltohexose as well. In contrast, α-methyl glucoside and cellobiose showed no binding. To specify the precise hydroxy groups that are directly involved in hydrogen bonding to MBP, further

Facile synthesis of nitrophenyl 2-acetamido-2-deoxy-α-D-mannopyranosides from ManNAc-oxazoline

• Karel Křenek,
• Petr Šimon,
• Lenka Weignerová,
• Barbora Fliedrová,
• Marek Kuzma and
• Vladimír Křen

Beilstein J. Org. Chem. 2012, 8, 428–432, doi:10.3762/bjoc.8.48

• capsular polysaccharides in Gram-negative bacteria. N-Acetyl-D-mannosamine (ManNAc) has been found to be, presumably, the strongest monosaccharidic ligand for the natural killer cells (NK-cells) activating protein NKR-P1 [1], and some ManNAc-containing oligosaccharides (e.g., GlcpNAc-β-(1→4)ManpNAc) have

• preparation of glycoproteins [9][10], various alcohol glycosides [11][12], phosphates [13] and oligosaccharides [12]. To the best of our knowledge, glycosylation of phenolic OH with oxazoline has not been accomplished so far. Therefore, we decided to test oxazoline 3 [14] glycosylation in our synthetic

Acceptor-influenced and donor-tuned base-promoted glycosylation

• Stephan Boettcher,
• Martin Matwiejuk and
• Joachim Thiem

Beilstein J. Org. Chem. 2012, 8, 413–420, doi:10.3762/bjoc.8.46

• glycosylation is a recently established stereoselective and regioselective approach for the assembly of di- and oligosaccharides by using partially protected acceptors and glycosyl halide donors. Initial studies were performed on partially methylated acceptor and donor moieties as a model system in order to

• . Keywords: glycosylation; oxyanion; reactivity; regioselectivity; Introduction For the assembly of oligosaccharides the complex and challenging control of regio- and stereochemistry has to be solved. Various contributions have facilitated enormously the access to complex oligosaccharide structures so far

• synthetic applications. To develop the synthetic potential and evolve this method into an applicable alternative pathway towards di-, tri- or oligosaccharides, more research needs to be done. So far, glycosylation reactions have been conducted by employing methyl α-glycopyranoside acceptors. Therefore, it

Synthesis in the glycosciences II

• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2012, 8, 411–412, doi:10.3762/bjoc.8.45

• to assemble as the oligosaccharides. And there is no other cell organelle that is less understood in its detailed biochemical function and the meaning of its supramolecular identity than the glycocalyx. Hence, the field of “glycomics” may comprise a rather infant field of the “omics era”, but it is