Antifreeze glycopeptide diastereomers

• Lilly Nagel,
• Carsten Budke,
• Axel Dreyer,
• Thomas Koop and
• Norbert Sewald

Beilstein J. Org. Chem. 2012, 8, 1657–1667, doi:10.3762/bjoc.8.190

• , peptides containing monosaccharide-substituted allo-L- and D-threonine building blocks were assembled by solid-phase peptide synthesis (SPPS). The retro-inverso AFGP analogue contained all amino acids in D-configuration, while the allo-L-diastereomer was composed of L-amino acids, like native AFGPs, with

• of sequential mutations on the adsorption of such synthetic AFGP analogues onto ice surfaces, and to corroborate the molecular mechanism of antifreeze activity. Recently, we published the synthesis of monosaccharide-based AFGP analogues containing glycine, proline and serine instead of alanine

• proline replacements [5]. These peptides exhibit less antifreeze activity than monosaccharide-substituted AFGP analogues without proline residues. Peptoid glycoconjugates with carbohydrate moieties attached by CuI catalyzed azide-alkyne cycloaddition (CuAAC) were devoid of antifreeze activity [17

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

• ][28][29]. One of the main interactions is the formation of hydrogen bonds, either direct or water-mediated, between the amino acid residues of the protein and the key binding hydroxy groups of the ligand, which are arranged in clusters presented by different monosaccharide units. Other factors include

• 12 [56] and 13 [12] (Figure 2). Synthesis of monosaccharide building blocks 8–11 Glucosamine acceptor 8 was prepared in two steps from the known [14] benzylidene 7: the benzylidene acetal was first hydrolyzed, and then the resulting diol (79%) was selectively benzoylated at O-6 (BzCl-collidine

• toward glycosylation [64][65][66]. However, we have reported the successful O-4 glycosylation of an N-acetylglucosamine monosaccharide acceptor using peracetylated gluco- and galactopyranose α-trichloroacetimidate donors under activation with 2 equivalents of BF3·OEt2 at room temperature or 40 °C [14][67

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

• 39 used in this study contained a mixture of high-mannose glycoforms; by treatment with endoglycosidase H (Endo-H), these glycans could be hydrolytically cleaved leaving the GlcNAc monosaccharide still attached to the protein. By treatment with a complex type glycan oxazoline donor and an Endo-M

• monosaccharide ligands have been prepared and evaluated [123]. The type 1 fimbriated Echerichia coli is a pathogen responsible for urinary tract infections with millions of cases every year [124]. The type 1 fimbriae have been identified to be a major contributor to these infections [125][126]. The FimH lectin

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

• , represents a strong candidate for the design of saccharide mimetics to be used as anti-tumor drugs. Results and Discussion Syntheses of saccharide mimetics Glycosylation of 3,4-bis(hydroxymethyl)furan (1) with 1.0 equiv imidate 2 in CH2Cl2 afforded 48% of monosaccharide 3. The synthesis of (4-{[(β-D

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

• aq. solution of NH4HCO3 to yield 18.35 g of compound 1 (3.7% starting from the root powder) and 15.42 g of compound 2 (3.1% starting from the root powder) as ammonium salts. The purity of 1 and 2 was assessed by analytical C18 reversed-phase HPLC and varied in a range of 97–99%. Monosaccharide

Synthesis and antifungal properties of papulacandin derivatives

• Marjolein van der Kaaden,
• Eefjan Breukink and
• Roland J. Pieters

Beilstein J. Org. Chem. 2012, 8, 732–737, doi:10.3762/bjoc.8.82

• . Apparently, the situation is different for the related disaccharide saricandan carrying different acyl chains, for which the monosaccharide analogue was not active [29]. Removing the galactose acyl chain from papulacandin B results in material that can still inhibit the target (in a spheroplasts glucan

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

• monosaccharide, this approach is unique due to its use of fully functionalized sugars, thus avoiding further refunctionalization steps to obtain the native C-glycoside. Results and Discussion Despite the numerous organometallic reactions performed with substituted glycals, to the best of our knowledge there has

Cyanoethylation of the glucans dextran and pullulan: Substitution pattern and formation of nanostructures and entrapment of magnetic nanoparticles

• Kathrin Fiege,
• Heinrich Lünsdorf,
• Sevil Atarijabarzadeh and
• Petra Mischnick

Beilstein J. Org. Chem. 2012, 8, 551–566, doi:10.3762/bjoc.8.63

• monosaccharide derivatives. Nanostructuring of the highly substituted cyanoethylpolysaccharides was performed by dialysis against a non-solvent. In the presence of ferromagnetic iron-oxide nanoparticles, multicore cyanoethylglucan-coated ferromagnetic nanoparticles were formed by selective entrapment. The

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

• , England 10.3762/bjoc.7.128 Abstract Diglycose derivatives, consisting of two monosaccharides linked at non-anomeric positions by a bridging nitrogen atom, have been synthesised. Conversion of one of the precursor monosaccharide coupling components into an unsaturated derivative enhances its

Synthesis of glycoconjugate fragments of mycobacterial phosphatidylinositol mannosides and lipomannan

• Benjamin Cao,
• Jonathan M. White and
• Spencer J. Williams

Beilstein J. Org. Chem. 2011, 7, 369–377, doi:10.3762/bjoc.7.47

• reductively-removed protecting groups such as benzyl ethers must be avoided owing to their incompatibility with the azido group when using H2/Pd or Na/NH3. We therefore sought to develop a synthesis based on the use of esters, silyl ethers and acetals only. Synthesis of monosaccharide building blocks

A bivalent glycopeptide to target two putative carbohydrate binding sites on FimH

• Thisbe K. Lindhorst,
• Kathrin Bruegge,
• Andreas Fuchs and
• Oliver Sperling

Beilstein J. Org. Chem. 2010, 6, 801–809, doi:10.3762/bjoc.6.90

• strategy [25] was applied to connect the monosaccharide and the trisaccharide part of the bivalent glycopeptide target structure 1 (Figure 2). Accordingly, retrosynthetic analysis of 1 leads to the 2-azidoethyl glycosides 2 and 5, with the azido group masking an amino function; two pentaglycine spacer

Preparation of aminoethyl glycosides for glycoconjugation

• Robert Šardzík,
• Gavin T. Noble,
• Martin J. Weissenborn,
• Andrew Martin,
• Simon J. Webb and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2010, 6, 699–703, doi:10.3762/bjoc.6.81

• selectivity and from the reaction mixture the pure β-anomer (>95:5) was isolated by column chromatography. The glucoside 11, galactoside 12 and mannoside 13 were prepared in moderate to good yield directly from the acetate (X = OAc in Scheme 1) giving rapid access to these monosaccharide derivatives. The

New amphiphilic glycopolymers by click functionalization of random copolymers – application to the colloidal stabilisation of polymer nanoparticles and their interaction with concanavalin A lectin

• Otman Otman,
• Paul Boullanger,
• Eric Drockenmuller and
• Thierry Hamaide

Beilstein J. Org. Chem. 2010, 6, No. 58, doi:10.3762/bjoc.6.58

• as glycoconjugates or as high molecular weight polymers, the actual “recognized” fractions are most often small oligosaccharides (3 to 10 carbohydrate units). Efficient binding has also been reported for monosaccharide ligands; for instance, galactose residues are targetable moieties for hepatocytes

• copolymer and their related syntheses were based on the following criteria: 1 - the monosaccharide must be anchored onto the polymer backbone by the use of a hydrophilic spacer in order to allow more freedom inside the aqueous phase after adsorption onto the polymer particles; 2 - syntheses must be simple

• enough to allow scale-up. Thus, we elected to use the simplest carbohydrates, i.e., those which are easy to prepare and easy to handle, e.g., the peracetylated monosaccharide 1 [16]. Although other derivatives, such as the 2,3,4,6-tetra-O-acetyl-1-O-trichloroacetimidoyl mannose might give rise to better

Bioorthogonal metabolic glycoengineering of human larynx carcinoma (HEp-2) cells targeting sialic acid

• Arne Homann,
• Riaz-ul Qamar,
• Sevnur Serim,
• Petra Dersch and
• Jürgen Seibel

Beilstein J. Org. Chem. 2010, 6, No. 24, doi:10.3762/bjoc.6.24

• signalling and cell-cell interactions. HEp-2 cells were investigated because of their metabolic capability to incorporate 2-azidoacetylamino-2-deoxy-(1,3,4,6)-tetraacetyl-β-D-glucopyranoside (Ac4GlcNAz, 16). The internalization of this acetylated monosaccharide was described previously as a diffusion process

Bis(oxazolines) based on glycopyranosides – steric, configurational and conformational influences on stereoselectivity

• Tobias Minuth and
• Mike M. K. Boysen

Beilstein J. Org. Chem. 2010, 6, No. 23, doi:10.3762/bjoc.6.23

• though N-acylated derivatives of D-glucosamine easily form bicyclic carbohydrate oxazolines, until recently only a few examples of mono(oxazoline) ligands [15][16][17] and the corresponding bis(oxazolines) [18] based on this monosaccharide have appeared in the literature. In the course of our work we

(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

• ; glycomimetics; pseudooligosaccharides; spaced sugars; Review Among the major classes of biomolecules, carbohydrates are characterized by nearly unlimited structural diversity. Monosaccharide units can combine to produce oligosaccharides in a number of permutations that increases rapidly with the number of

• units present, more so than is the case with other biomolecules such as polypeptides or oligonucleotides. This is determined by the stereochemical identity of the monosaccharide units present (e.g. glucose, galactose, mannose), their glycosidic linkage positions (e.g. 1→4, 1→6), the nature at anomeric

• longer thiourea-linked glycooligomers with linear dendritic and branched architectures, our group has recently reported an efficient synthetic strategy based on the use of AB, AB2 and ABC-type monosaccharide building blocks containing isothiocyanate (A), azido (B) or carbamate groups (C) (Scheme 4) [85

Convergent syntheses of Le^X analogues

• An Wang,
• Jenifer Hendel and
• France-Isabelle Auzanneau

Beilstein J. Org. Chem. 2010, 6, No. 17, doi:10.3762/bjoc.6.17

• competitive binding experiments, conjugation to carrier proteins and immobilization on gold. An N-acetylglucosamine monosaccharide acceptor was first glycosylated at O-4 with a galactosyl imidate. This coupling was performed at 40 °C under excess of BF3·OEt2 activation and proceeded best if the acceptor

• towards glycosylation of the N-acetylated and phthalimido acceptors 5 and 6, respectively, that both carry a 6-azidohexyl aglycon (Figure 2). Synthesis of monosaccharide building blocks. The 6-chlorohexyl acceptor 4 was prepared in four steps from the known [43] chlorohexyl glucoside 10 (Scheme 1). Thus

• glucosylation of an N-acetylglucosamine monosaccharide acceptor using a peracetylated glucopyranose α-trichloroacetimidate donor under activation with 2 equiv of BF3·OEt2 at room temperature [51]. We applied similar conditions: 2 equiv BF3·OEt2, 5 equiv of donor, 1 h at 40 °C for the coupling of donors 7 and 8

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

• ]. Carba analogues of oligosaccharides (carbasugars), generated by replacing the endocyclic O-atom in a monosaccharide [1][2][3][4][5][6][7][8][9][10][11], are thought to be better drug candidates than natural sugars, since they are hydrolytically stable. Spurred on by the heightened interest in the design

Recognition properties of receptors consisting of imidazole and indole recognition units towards carbohydrates

• Monika Mazik and
• André Hartmann

Beilstein J. Org. Chem. 2010, 6, No. 9, doi:10.3762/bjoc.6.9

• method (see Table 3). Studies performed in 5% DMSO-d6 in CDCl3 revealed that K11 = 40700 M−1 and K12 = 800 M−1. The titration experiments with β-galactoside 8a clearly showed that receptor 5 is less effective towards this monosaccharide than the imidazole-based receptor 4 but much more effective than the

• powerful monosaccharide receptor than the indole-based compound 5 and the previously described receptors 1–3. Compared to 1 and 2, incorporating only one imidazole or indole recognition unit, receptor 5 showed increased affinity to β-galactoside but decreased affinity to β-glucoside. The binding affinity

Cimicifoetisides A and B, two cytotoxic cycloartane triterpenoid glycosides from the rhizomes of Cimicifuga foetida, inhibit proliferation of cancer cells

• Li-Rong Sun,
• Chen Qing,
• Yan-Li Zhang,
• Shu-Yu Jia,
• Zhong-Rong Li,
• Shen-Ji Pei,
• Ming-Hua Qiu,
• Michael L. Gross and
• Samuel X. Qiu

Beilstein J. Org. Chem. 2007, 3, No. 3, doi:10.1186/1860-5397-3-3

• -monosaccharide, along with seven known compounds, were isolated and were shown to exhibit potent cytotoxicity against two human cancer cell lines. This report describes the isolation, structure elucidation, and cytotoxicity evaluation of these isolates. 2. Results and discussions Cimicifoetiside A (1) (see

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

• , as we have demonstrated for C-substituted monosaccharide[34] and C-linked disaccharide mimetics,[35][36][37] a wide range of stereochemically diverse aza-C-linked disaccharide analogues could be prepared (see piperidine ring systems A-D and tetrahydropyran ring systems d, d' and e).† († In this