Cyclodextrin–polysaccharide-based, in situ-gelled system for ocular antifungal delivery

• Anxo Fernández-Ferreiro,
• Noelia Fernández Bargiela,
• María Santiago Varela,
• Maria Gil Martínez,
• Maria Pardo,
• Antonio Piñeiro Ces,
• José Blanco Méndez,
• Miguel González Barcia,
• Maria Jesus Lamas and
• Francisco.J. Otero-Espinar

Beilstein J. Org. Chem. 2014, 10, 2903–2911, doi:10.3762/bjoc.10.308

• the polysaccharide concentration or in the ratio of gels with and without cyclodextrins. Table 2 shows the results of the fitting to determine the quantity of fluconazole release up to 120 min using Higuchi kinetics [28]. The good fits obtained suggest that release is controlled by the diffusion of

• containing 5% of CD and 0.5% of the respective polysaccharide. Ocular cytotoxicity studies of HPBCD and SBECD in primary corneal human keratocytes, using real-time xCELLigence impedance analysis. (a) Kinetic curve survival rates for HPBCD; (b) Kinetic curve survival rates for SBECD; (c) Evolution of IC50 vs

Synthesis of the pentasaccharide repeating unit of the O-antigen of E. coli O117:K98:H4

• Pintu Kumar Mandal

Beilstein J. Org. Chem. 2014, 10, 2724–2728, doi:10.3762/bjoc.10.287

• kidneys [10][11]. The O-specific polysaccharide of E. coli O117:K98:H4 is a linear pentasaccharide repeating unit consisting of D-galactosamine, D-glucose, D-galactose, and L-rhamnose (Figure 1) [12]. Vaccination is the recent thrust in the drug discovery program to prevent bacterial infections. Several

• pentasaccharide repeating unit of the O-specific polysaccharide of E. coli O117:K98:H4 as its 3-aminopropyl glycoside is presented herein (Figure 2). The 3-aminopropyl group would be suitable for attachment of the pentasaccharide to any surface or carrier proteins. Results and Discussion The target

• pentasaccharide repeating unit of the O-specific polysaccharide of E. coli O117:K98:H4. Structure of the synthesized pentasaccharide (1) and its precursor intermediates. Reagents and conditions: (a) (i) acetic anhydride, pyridine, room temperature, 2 h; (ii) NaBH3CN, HCl/Et2O, 5 °C, 2 h, 77% overall yield

Synthesis of aromatic glycoconjugates. Building blocks for the construction of combinatorial glycopeptide libraries

• Markus Nörrlinger and
• Thomas Ziegler

Beilstein J. Org. Chem. 2014, 10, 2453–2460, doi:10.3762/bjoc.10.256

• communication, signal transduction, pathogen recognition or immunological responses [1][2][3][4]. In order to investigate these processes it is essential that a large amount of the respective polysaccharide structure is available. Unfortunately, isolation of pure oligosaccharides from natural sources is

Synthesis and immunological evaluation of protein conjugates of Neisseria meningitidis X capsular polysaccharide fragments

• Laura Morelli,
• Damiano Cancogni,
• Marta Tontini,
• Alberto Nilo,
• Sara Filippini,
• Paolo Costantino,
• Maria Rosaria Romano,
• Francesco Berti,
• Roberto Adamo and
• Luigi Lay

Beilstein J. Org. Chem. 2014, 10, 2367–2376, doi:10.3762/bjoc.10.247

• , 53100 Siena, Italy 10.3762/bjoc.10.247 Abstract A vaccine to prevent infections from the emerging Neisseria meningitidis X (MenX) is becoming an urgent issue. Recently MenX capsular polysaccharide (CPS) fragments conjugated to CRM197 as carrier protein have been confirmed at preclinical stage as

• the native polymer and conjugated to the same protein. This finding suggests that oligomers longer than three repeating units are possibly needed to mimic the activity of the native polysaccharide. Keywords: carbohydrates; glycoconjugates; immunology; multivalent glycosystems Neisseria meningitidis

• meningitis epidemics have been recorded in Africa, in an area termed “the meningitis belt”, extending from Senegal to Ethiopia and including 21 countries with a population of over 300 million people. According to the chemical composition of the bacterial capsular polysaccharide (CPS) [1], 13 serogroups of N

Sacrolide A, a new antimicrobial and cytotoxic oxylipin macrolide from the edible cyanobacterium Aphanothece sacrum

• Naoya Oku,
• Miyako Matsumoto,
• Kohsuke Yonejima,
• Keijiroh Tansei and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2014, 10, 1808–1816, doi:10.3762/bjoc.10.190

• . However, to date, only two substances have been reported: pseudovitamin B12 [10] and sulfated polysaccharide sacran [11]. We evaluated the antimicrobial activity of this alga and found that a lipophilic fraction of an ethanolic extract showed inhibitory activity against several microbes. Activity-guided

Expedient synthesis of 1,6-anhydro-α-D-galactofuranose, a useful intermediate for glycobiological tools

• Luciana Baldoni and
• Carla Marino

Beilstein J. Org. Chem. 2014, 10, 1651–1656, doi:10.3762/bjoc.10.172

• ]. Benzylated 2 was polymerized under cationic conditions, which afforded a material not completely characterized, presumably formed by β-D-Galf units [15]. Free compound 2, as well as the D-Manf and D-Glcf analogues, was also polymerized under cationic conditions to yield a hyperbranched polysaccharide with α

A promising cellulose-based polyzwitterion with pH-sensitive charges

• Thomas Elschner and
• Thomas Heinze

Beilstein J. Org. Chem. 2014, 10, 1549–1556, doi:10.3762/bjoc.10.159

• Thomas Elschner Thomas Heinze Center of Excellence for Polysaccharide Research, Institute for Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University of Jena, Humboldtstraße 10, D-07743 Jena, Germany 10.3762/bjoc.10.159 Abstract A novel polyzwitterion possessing weak ionic

• repeating unit, but not in the same side chain. Moreover, regioselective functionalization is possible [13]. In contrast to synthetic polybetaines an increased solubility could be expected for polysaccharide derivatives and, furthermore, biopolymers possess an inherent biocompatibility and biodegradability

• ][18][19][20]. However, the polymers contain mostly a permanent cationic- or anionic charge, which may lead to limitations in solubility. Thus, there is an increasing interest in novel biobased, zwitterionic polysaccharide derivatives in research and industry. In the present work the structure design

Efficient routes toward the synthesis of the D-rhamno-trisaccharide related to the A-band polysaccharide of Pseudomonas aeruginosa

• Aritra Chaudhury,
• Sajal K. Maity and
• Rina Ghosh

Beilstein J. Org. Chem. 2014, 10, 1488–1494, doi:10.3762/bjoc.10.153

• the A-band polysaccharide of Pseudomonas aeruginosa. One of the key steps involved 6-O-deoxygenation of either partially or fully acylated 4,6-O-benzylidene-1-thiomannopyranoside by radical-mediated redox rearrangement in high yields and regioselectivity. The D-rhamno-thioglycosides so obtained

• -rhamno-trisaccharide. The application of the reported regioselective radical-mediated deoxygenation on 4,6-O-benzylidene D-manno thioglycoside (hitherto unexplored) has potential for ramification in the field of synthesis of oligosaccharides based on 6-deoxy hexoses. Keywords: A-band polysaccharide; D

• rendering O-antigen-based vaccines ineffective. But the conservation of the A-band polysaccharide even in the colonized form makes this repeating unit a viable candidate for A-band polysaccharide-based vaccines which can avoid the vulnerability applicable to their O-antigen-based counterparts [16]. Hence

Design, automated synthesis and immunological evaluation of NOD2-ligand–antigen conjugates

• Marian M. J. H. P. Willems,
• Gijs G. Zom,
• Nico Meeuwenoord,
• Ferry A. Ossendorp,
• Herman S. Overkleeft,
• Gijsbert A. van der Marel,
• Jeroen D. C. Codée and
• Dmitri V. Filippov

Beilstein J. Org. Chem. 2014, 10, 1445–1453, doi:10.3762/bjoc.10.148

• -binding oligomerization domain (NOD) receptors [17] NOD1 [18] and NOD2 [19] were discovered to be intracellular PRRs [20][21]. NOD1 and NOD2 recognize specific parts of peptidoglycan (PG), found in the bacterial cell wall [22][23]. PG consists of a polysaccharide chain of β-(1–4) linked N

Carbohydrate PEGylation, an approach to improve pharmacological potency

• M. Eugenia Giorgi,
• Rosalía Agusti and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 1433–1444, doi:10.3762/bjoc.10.147

• and chitosan derivatives for pharmaceutical applications was described [22]. Chitosan is the polysaccharide obtained from the abundant chitin by alkali or enzymatic degradation. It consists of a backbone of β-(1→4)-linked D-glucosamine units with a variable degree of N-acetylation. The protonated

• protonable amines into neutral amide or carbamate linkers. Even though PEGylation of chitosan via the amino group is the most commonly used method a number of examples of polysaccharide derivatisation on the hydroxy groups have been reported. Chitosan-O-poly(ethylene glycol) graft copolymers were synthesized

• hydroxy-activated polysaccharides with amino-terminated methoxy PEGs. The reaction was applied to inulin [63] and to a polysaccharide from Radix Ophiopogonis [64] for improving their pharmacokinetic properties. A similar activation of the sugar has been previously applied to a dextran for further

Convergent synthesis of a tetrasaccharide repeating unit of the O-specific polysaccharide from the cell wall lipopolysaccharide of Azospirillum brasilense strain Sp7

• Pintu Kumar Mandal,
• Debashis Dhara and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2014, 10, 293–299, doi:10.3762/bjoc.10.26

• the O-specific polysaccharide of the LPS of A. brasilense Sp7 strain as its 2-aminoethyl glycoside (Figure 1) is presented herein. Results and Discussion The target tetrasaccharide 1 has been synthesized as its 2-aminoethyl glycoside (Figure 1) to facilitate its conjugation with a suitable substrate

• summary, a straightforward and convergent synthesis of the tetrasaccharide 1 as its 2-aminoethyl glycoside corresponding to the O-specific polysaccharide of the LPS of A. brasilense strain Sp7 has been presented. The use of thioglycosides both as glycosyl donor and acceptor according to the concept of the

Straightforward synthesis of a tetrasaccharide repeating unit corresponding to the O-antigen of Escherichia coli O16

• Manas Jana and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2013, 9, 1757–1762, doi:10.3762/bjoc.9.203

• meningitis are O1, O6, O7, O16, O18 and O83 [7]. Like many other E. coli strains, meningitis causing E. coli O16 is encapsulated and exhibits the K1 polysaccharides [8]. The structure of the E. coli O16 polysaccharide has been established by Jann et al. [9], which is a tetrasaccharide repeating unit

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

• Guillaume Moreira,
• Laurence Charles,
• Mohamed Major,
• Florence Vacandio,
• Yohann Guillaneuf,
• Catherine Lefay and
• Didier Gigmes

Beilstein J. Org. Chem. 2013, 9, 1589–1600, doi:10.3762/bjoc.9.181

• of applications of cellulose, a glucose-based polysaccharide, is limited by its inherently poor mechanical properties. The grafting of synthetic polymer chains by, for example, a “grafting from” process may provide the means to broaden the range of applications. The nitroxide-mediated polymerization

• of crucial importance to perform the graft modification of polysaccharide by NMP. The aim of this work is to offer a model study of the stability of the SG1 nitroxide in organic media in the presence of unprotected glucose or cellobiose (used as a model of cellulose) and in the presence of lithium

• -functionalization of a preformed synthetic polymer chain grafted to the polysaccharide backbone, (ii) the “grafting through” method, which consists of copolymerizing premade vinyl-functionalized polysaccharides with a comonomer and (iii) the “grafting from” strategy where the grafted polymer chains grow from the

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• converting primary hydroxyl groups to the corresponding carboxylic functions, maintaining the original backbone of the polysaccharide, is of major interest for different applications [46][47]. By comparing different activation approaches, including transition-metal complexes, Coseri found that the NHPI/AQ

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

• -Galf-containing glycoconjugates, the mechanisms by which α-D-Galf units are incorporated remain unclear. Penicillium varians is a non-pathogenic fungus that produces varianose, a polysaccharide containing both α- and β-D-Galf units, which can be used as a model for biosynthetic studies on α-D-Galf

• , establishing the connection between the glycan structure and its biological function, a discipline called functional glycomics, is one of the most challenging areas nowadays and requires a broad interdisciplinary approach. Penicillium varians elaborates an unusual polysaccharide called varianose [3] that

• hydrolysis, which preferentially cleaves the furanosidic linkages, allowed the isolation and characterization of the disaccharide with the reducing galactose isomerized to the more stable pyranose form. The same disaccharide unit is present in the cell-wall polysaccharide of Talaromyces flavus [5] and in the

The use of glycoinformatics in glycochemistry

• Thomas Lütteke

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

• (glycosyltransferases, glycoside hydrolases, polysaccharide lyases and carbohydrate esterases) as well as proteins that feature carbohydrate-binding modules is CAZy (Carbohydrate Active Enzymes). This database classifies proteins by sequence comparison and clusters them into families by using well-established

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

• saccharides. Glycosaminoglycans (GAG) are long polysaccharide chains containing sulfated saccharides of uronic acids (either iduronic or glucuronic acid) and glucosamine or galactosamine as repetitive disaccharide units. GAGs exist at the cell-surface as well as in the ECM and are attached to proteins [16

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

• biocompatibility, dextrans are applied as blood-plasma expander. Dextran derivatives are used in many biomedical and bioanalytical applications [34] and are the subject of further developments in this field [35]. Therefore, we selected pullulan and dextran as candidates for a linear and a branched polysaccharide

• infrared spectroscopy (ATR–IR). Gas–liquid chromatography (GLC) in combination with mass spectrometry (MS) was employed for the analysis of glucose derivatives after depolymerization of the cyanoethylglucans. The DS of heterogenic atoms containing polysaccharide derivatives can be followed by elementary

• polysaccharide. DMSO-d6 was used as a solvent for the derivatives with a DS > 2 and D2O for the less-substituted polyglucans. The spectra of O-cyanoethylglucans show strong peak broadening and therefore worse resolution compared to the starting material (Figure 4 and Figure 5). The signal at 2.82 ppm in D2O and

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

• therapeutics than the earlier used anti-shigellosis agents [9][10]. Because of the high antigenic nature of the O-antigens, antibodies against the O-specific polysaccharide of a particular Shigella strain have the potential to control Shigella infections [11][12][13][14]. A number of reports have been cited

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

• ], employing type 1 fimbriated E. coli bacteria and mannan-coated microtiter plates. In this assay a mannosidic ligand competes with the polysaccharide mannan adsorbed on a polystyrene microtiter plate for FimH-mediated binding to the type 1 fimbriated bacteria. The inhibitory ligand is employed in serial

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

• College Dublin, Belfield, Dublin 4, Ireland, Phone: +353 17162318 10.3762/bjoc.6.80 Abstract Background: In bacteria with truncated lipopolysaccharide structures, i.e., lacking the O-antigen polysaccharide part, core structures are exposed to the immune system upon infection and thus their use as

• six serotypes, a–f, related to the structure of the capsular polysaccharide usually surrounding the bacterium [1]. Among these serotypes, type b is the cause of the most severe diseases, i.a. meningitis and pneumonia. However, there are now several commercial vaccines against this serotype that have

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

• addition to the hydrophilicity conferred by the carbohydrate moiety, specific targeting may be result from coating nanoparticles with oligo- or polysaccharide chains since the carbohydrate moieties play an essential role in molecular recognition processes. Although the carbohydrate ligands occur naturally