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

• therapeutics against this organism. Since, bacterial cell-wall lipopolysaccharides play important roles in the pathogenicity of the virulent strains, it would be pertinent to develop glycoconjugate therapeutics based on the cell-wall oligosaccharide haptens to reduce the number of infections [9][10][11][12

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

• external partners such as cells and viruses. Straightforward access to sialosides is required in order to study their biological functions on a molecular level. Here, automated oligosaccharide synthesis was used to facilitate the preparation of this class of biomolecules. Our strategy relies on novel

• diverse set of glycans rapidly and efficiently. The automated synthesizer proved capable of performing iterative glycosylation–deprotection cycles under conditions commonly employed for solution-phase oligosaccharide synthesis. The synthetic strategy relies on the solid support-bound linker 17 (Scheme 3

• semi-protected oligosaccharide. The automated synthesis of 20 (Scheme 3) started with the glycosylation of resin-bound linker 17 with glucosamine building block 18 (2 × 5 equiv) [5] in the presence of N-iodosuccinimide and triflic acid. Fluorenylmethoxycarbonyl (Fmoc) removal was followed by

Synthesis of 4” manipulated Lewis X trisaccharide analogues

• Christopher J. Moore and
• France-Isabelle Auzanneau

Beilstein J. Org. Chem. 2012, 8, 1134–1143, doi:10.3762/bjoc.8.126

• yields. Keywords: chlorodeoxygalactose; fluorodeoxygalactose; Lewis X analogues; oligosaccharide synthesis; Introduction A glycolipid displaying the dimeric Lex hexasaccharide (dimLex) has been identified as a cancer associated carbohydrate antigen, particularly prevalent in colonic and liver

The use of glycoinformatics in glycochemistry

• Thomas Lütteke

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

• challenge for glycoinformatics, but it also offers many possibilities to synthesize carbohydrates or glycomimetics that target specific pathogen proteins. For example, oligosaccharide motifs that are found in surface carbohydrates of pathogens, but not in host organisms or in symbiotes, can serve as

• that structures that have not been observed before or that are missing from the database will not be identified this way. This problem also applies to programs that use experimental MSn data of oligosaccharide standards to assign MSn fragments of larger glycans, such as GLYCH [129] or MSn FragLib [140

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

• hydrolysis reaction could be avoided [84][85]. A number of successful preparations of N-glycopeptides and N-glycoproteins have since then been successfully prepared by using oxazoline oligosaccharide donors; the synthesis of a HIV gp120 glycopeptide fragment, the HIV gp41 peptide, and the RNase B

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

• microenvironment resulting in an increased malignancy. Schmidt’s imidate strategy offers an effective method to synthesize libraries of various oligosaccharide mimetics. With the aim to perturb interactions of tumor cells with extracellular matrix proteins and host cells, molecules with 3,4-bis(hydroxymethyl)furan

• oligosaccharide mimetics containing furan as the core molecules to modulate cell–ECM interactions. Especially 3,4-bis{[(β-D-galactopyranosyl)oxy]methyl}furan (BGF) had shown bioactivity by blocking the adhesion of murine B16F10 melanoma cells to murine fibronectin [15]. We have now obtained similar results with

• fucosylated oligosaccharides Lewisy and H are strongly expressed on the cellular extensions that form the first contacts between endothelial cells. From these experiments we concluded that fucosylation of oligosaccharide chains is necessary for the first steps in the lining-up of endothelial cells and ensuing

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

• similar sets of two oligosaccharide chains, which are 3-O-linked to the triterpenoid part trisaccharide α-L-Arap-(1→3)-[α-D-Galp-(1→2)]-β-D-GlcpA and pentasaccharide β-D-Xylp-(1→3)-β-D-Xylp-(1→3)-α-L-Rhap-(1→2)-[β-D-Quip-(1→4)]-β-D-Fucp connected through an ester linkage to C-28. The structures of the

• 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

• bidesmosidic nature of the genin, which is glycosydated at C-3 and esterified to an oligosaccharide. The structures of both the trisaccharide and pentasaccharide fragments of compound 2 are similar to those established for compound 1. Thus the structure of 2 was elucidated as gypsogenin 28-O-β-D-xylopyranosyl

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

• products at a reaction temperature of 60 °C and long incubation time (Figure S12 in Supporting Information File 1). No further optimisation was performed but would be required for better conversion of poly-LacNAc oligosaccharide substrates, especially regarding the reaction temperature as heating of the

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

• oligosaccharide assembly by minimizing or even eliminating additional manipulations between coupling steps, are based either on chemoselective or on selective activation of leaving groups [6]. The use of selective activation [7] offers more flexibility than that of the chemoselective activation which relies on

• oligosaccharide synthesis [6]. However, suitable reaction conditions for the orthogonal activation of these two classes of leaving groups are yet to be found. Commonly, O-glycosides are too stable to be used as effective glycosyl donors [21]. Pent-4-enyl O-glycosides introduced by Fraser-Reid are unique in this

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

• interactions for the oligosaccharide binding as well [20][21][22]. Specifically, the 2-OH and the 2′-OH moieties are involved in an intricate hydrogen bonding network including the carboxy group of Glu111 and Asp65 and the amino group of Lys15 and Trp62, respectively. We thus decided to synthesize 2-19F

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

• . 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

Synthesis in the glycosciences II

• Thisbe K. Lindhorst

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

• . Expertise and rational planning have allowed the utilization of carbohydrates in stereoselective synthesis and the employment of enzymes in oligosaccharide synthesis. Analytical and pharmacological knowhow have disclosed polysaccharide and glycoconjugate structures, their biological effects and their

Convergent synthesis of the tetrasaccharide repeating unit of the O-antigen of Shigella boydii type 9

• Abhishek Santra and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2011, 7, 1182–1188, doi:10.3762/bjoc.7.137

• glycoside in high yield. Keywords: diarrhea; glycosylation; O-antigen; oligosaccharide; Shigella boydii; Introduction Diarrhoeal disease is a common cause of death in the tropical countries and it is the second mostly causing infant deaths worldwide. Shigella is one of the well-studied human pathogens

Amine-linked diglycosides: Synthesis facilitated by the enhanced reactivity of allylic electrophiles, and glycosidase inhibition assays

• Ian Cumpstey,
• Jens Frigell,
• Elias Pershagen,
• Tashfeen Akhtar,
• Elena Moreno-Clavijo,
• Inmaculada Robina,
• Dominic S. Alonzi and
• Terry D. Butters

Beilstein J. Org. Chem. 2011, 7, 1115–1123, doi:10.3762/bjoc.7.128

• using the oligosaccharide Glc2Man7GlcNAc2 as substrate and using the free oligosaccharide (FOS) assay in cultured cells [49]. The Alt(N2–6)Man derivative 29 showed some inhibitory activity, with IC50 ca. 500 μM. None of the other compounds tested inhibited the enzyme at 100 μM concentration. Such amine

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• g∙mol−1 were measured. Another group reported the reaction between chitosan oligosaccharide with ethylene glycol diglycidyl ether to encapsulate paclitaxel in methylene dichloride-water miniemulsions [99]. The encapsulation was determined by HPLC to be between ~84% and ~92% depending on the ratio

Synthesis of 6-PEtN-α-D-GalpNAc-(1–>6)-β-D-Galp-(1–>4)-β-D-GlcpNAc-(1–>3)-β-D-Galp-(1–>4)-β-D-Glcp, a Haemophilus influenzae lipopolysacharide structure, and biotin and protein conjugates thereof

• Andreas Sundgren,
• Martina Lahmann and
• Stefan Oscarson

Beilstein J. Org. Chem. 2010, 6, 704–708, doi:10.3762/bjoc.6.80

• the title compound have been constructed to allow further use in biological experiments. Keywords: conjugate vaccines; glycoconjugates; Haemophilus influenzae; lacto-N-neotetraose; oligosaccharide synthesis; thioglycosides; Introduction Haemophilus influenzae are Gram-negative bacteria divided into

• proven to be highly effective [2]. These vaccines are glycoconjugate vaccines, based on capsular poly- or oligosaccharide structures, either native or synthetic [3][4], linked to a carrier protein. The lipopolysaccharide (LPS) of H. influenzae shows a huge structural variety and hence non-capsulated

(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties

• José L. Jiménez Blanco,
• Fernando Ortega-Caballero,
• Carmen Ortiz Mellet and
• José M. García Fernández

Beilstein J. Org. Chem. 2010, 6, No. 20, doi:10.3762/bjoc.6.20

• carbohydrates. Such oligosaccharide mimetics are potential therapeutic agents against HIV and other infections, against cancer, diabetes and other metabolic diseases. An efficient strategy to access this type of compounds is the replacement of the glycosidic linkage by amide or pseudoamide functions such as

• thiourea, urea and guanidine. In this review we summarise the advances over the last decade in the synthesis of oligosaccharide mimetics that possess amide and pseudoamide linkages, as well as studies focussing on their supramolecular and recognition properties. Keywords: carbopeptoids; glycoclusters

• centres (α or β), the presence of additional substituents such as sulfate or acyl groups and the overall degree of branching. The molecular diversity of oligosaccharide offers a valuable tool for drug discovery in the areas of biologically important oligosaccharides, glycoconjugates and molecular

Chemical synthesis using enzymatically generated building units for construction of the human milk pentasaccharides sialyllacto-N-tetraose and sialyllacto-N-neotetraose epimer

• Dirk Schmidt and
• Joachim Thiem

Beilstein J. Org. Chem. 2010, 6, No. 18, doi:10.3762/bjoc.6.18

• majority is performed either by classical chemical methods or exclusively by enzymatic procedures. Even although considerable progress has been reported during the recent decades, every synthesis of a complex heterooligosaccharide still represents a challenge. To arrive at an oligosaccharide structure with

Synthesis in the glycosciences

• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2010, 6, No. 16, doi:10.3762/bjoc.6.16

• . Since the isolation of those complex glycans which are active in cellular communication is problematic, oligosaccharide synthesis is an important area of research. Moreover, what Professor Hans Paulsen, one of the greatest exponents of glycoside synthesis, observed in 1982 [2] still holds true today

• : “Although we have now learned to synthesize oligosaccharides, it should be emphasized that each oligosaccharide synthesis remains an independent problem, whose resolution requires considerable systematic research and a good deal of know-how. There are no universal reaction conditions for oligosaccharide

• syntheses”. It is therefore not surprising that the majority of contributions collected in this Thematic Series deal with methods, both chemical and enzymatic, for oligosaccharide synthesis. One approach to deal with the problem of glycoside synthesis is the preparation of so-called glycomimetics. This is a

Synthesis of a new class of aminocyclitol analogues with the conduramine D-2 configuration

• Latif Kelebekli,
• Yunus Kara and
• Murat Celik

Beilstein J. Org. Chem. 2010, 6, No. 15, doi:10.3762/bjoc.6.15

• ][10][11], many of which are widely used for the treatment of diseases in humans, animals and plants [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Glycosidase and related enzymes are involved in the biosynthesis of the oligosaccharide chains [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15

Acid- mediated reactions under microfluidic conditions: A new strategy for practical synthesis of biofunctional natural products

• Katsunori Tanaka and
• Koichi Fukase

Beilstein J. Org. Chem. 2009, 5, No. 40, doi:10.3762/bjoc.5.40

• prominent biological activity in a “practical” and a “industrial” manner. Keywords: acid-mediated reaction; microreactor; natural products synthesis; oligosaccharide; pristane; Introduction A continuous flow microreactor, an innovative technology, has been used to realize efficient mixing and fast heat

• conditions enabled the preparation of key synthetic intermediates for oligosaccharides on a multi-gram scale, eventually leading to a total synthesis of the asparagine-linked oligosaccharide (N-glycan) [32]. A significant improvement has also been achieved for dehydration, which resulted in the industrial

• industrial synthesis of the bioactive natural products. Review 1. Application of microfluidic systems to the synthesis of asparagine-linked oligosaccharides Among the various types of oligosaccharide structures, asparagine-linked oligosaccharides (N-glycans) are prominent in terms of diversity and complexity

Dimerization of propargyl and homopropargyl 6-azido- 6-deoxy- glycosides upon 1,3-dipolar cycloaddition

• Nikolas Pietrzik,
• Daniel Schmollinger and
• Thomas Ziegler

Beilstein J. Org. Chem. 2008, 4, No. 30, doi:10.3762/bjoc.4.30

• of highly glycosylated beta-peptides that can mimic specific oligosaccharide-protein interactions prompted us to further search for efficient routes toward glycosylated amino acid building blocks derived from asparaginic acid in which the glycon is bound to C-1 of the asparaginic acid through

• libraries of highly glycosylated peptides, some members of which were indeed shown to behave like oligosaccharide mimics capable to specifically bind lectins [1][4]. In order to increase the structural diversity of the aforementioned building blocks, we contemplated using as the spacer entity 1,2,3

Methods for the synthesis of polyhydroxylated piperidines by diastereoselective dihydroxylation: Exploitation in the two-directional synthesis of aza-C-linked disaccharide derivatives

• Andrew Kennedy,
• Adam Nelson and
• Alexis Perry

Beilstein J. Org. Chem. 2005, 1, No. 2, doi:10.1186/1860-5397-1-2

• LS2 9JT, UK School of Chemistry, University of Leeds, Leeds LS2 9JT, UK 10.1186/1860-5397-1-2 Abstract Background Many polyhydroxylated piperidines are inhibitors of the oligosaccharide processing enzymes, glycosidases and glycosyltransferases. Aza-C-linked disaccharide mimetics are compounds in

• configurations to be prepared. The work demonstrates that highly unsymmetrical molecules may be prepared using a two directional approach. The deprotected compounds may have potential as inhibitors of oligosaccharide-processing enzymes and as tools in chemical genetic investigations. Introduction Many

• polyhydroxylated piperidines are potent inhibitors of the oligosaccharide processing enzymes, glycosidases and glycosyltransferases.[1][2][3] For example, deoxymannojirimycin, 1, and deoxynojirimycin, 2, are selective mannosidase and glucosidase inhibitors respectively.[4][5] In these molecules, the nitrogen atom