Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates

• Yuichi Yoshimura,
• Hideaki Wakamatsu,
• Yoshihiro Natori,
• Yukako Saito and
• Noriaki Minakawa

Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137

• glycols, epoxides, and olefins takes place by the action of hypervalent iodine [38][71][72]. For example, Havare and Plattner reported the oxidative cleavage of α-aryl aldehydes using iodosylbenzene to give chain-shortened carbonyl compounds and formaldehyde [71]. In the field of carbohydrate chemistry

• towards oligosaccharides, which would also contribute to the identification and development of drug candidates. For example, cancer immunotherapy based on vaccines derived from carbohydrate antigen–adjuvant combinations has received much attention in recent years [75][76][77]. However, the difficulties

• associated with the isolation of tumor-associated carbohydrate antigens from natural sources have impeded extensive research. Thus, the most promising approach to the supply of these antigens is to develop a suitable method for their chemical synthesis. To date, various glycosylation reactions capable of

Synthetic avenues towards a tetrasaccharide related to Streptococcus pneumonia of serotype 6A

• Aritra Chaudhury,
• Mana Mohan Mukherjee and
• Rina Ghosh

Beilstein J. Org. Chem. 2018, 14, 1095–1102, doi:10.3762/bjoc.14.95

• ; oligosaccharides; stereoselectivity; total synthesis; Introduction Complex glycans serve as attractive targets for carbohydrate-based vaccines and therapeutics [1][2][3]. Streptococcus pneumonia (SPn) has been posing a serious threat in recent times. It is a major cause of pneumonia, bacteraemia, and meningitis

• most important causes of invasive pneumonococcal diseases [7]. These facts have led to extensive research towards the establishment of polysaccharide structures associated with the SPn serogroup 6 [8][9] (Figure 1). Initially, it was thought that due to their similar carbohydrate core structures the

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• synthesized in order to investigate the molecular basis of carbohydrate–minor groove DNA interactions by Vicent et al. [95]. NMR spectroscopy and molecular modeling studies further confirmed the existence of directional intramolecular hydrogen bonds and CH–π interactions, which results in stabilizing these

A stereoselective and flexible synthesis to access both enantiomers of N-acetylgalactosamine and peracetylated N-acetylidosamine

• Bettina Riedl and
• Walther Schmid

Beilstein J. Org. Chem. 2018, 14, 856–860, doi:10.3762/bjoc.14.71

• peracetylated D-IdoNAc 2c. Conclusion The presented synthetic route was successfully used to prepare both, D- and L-GalNAc, from non-carbohydrate starting materials over 9 steps with overall yields of 22% and 12%, respectively. Our approach combines the Sharpless epoxidation and Pd-catalyzed azide substitution

AuBr₃-catalyzed azidation of per-O-acetylated and per-O-benzoylated sugars

• Jayashree Rajput,
• Srinivas Hotha and
• Madhuri Vangala

Beilstein J. Org. Chem. 2018, 14, 682–687, doi:10.3762/bjoc.14.56

• applications and further demonstrates the value of gold catalysis in carbohydrate chemistry. Experimental General experimental methods: Chemicals and materials were obtained from commercial sources and used without further purification unless otherwise noted. 1H and 13C NMR spectra were recorded on a 400 MHz

Carbohydrate inhibitors of cholera toxin

• Vajinder Kumar and
• W. Bruce Turnbull

Beilstein J. Org. Chem. 2018, 14, 484–498, doi:10.3762/bjoc.14.34

• released by Vibrio cholera in the host’s intestine. The toxin enters intestinal epithelial cells after binding to specific carbohydrates on the cell surface. Over recent years, considerable effort has been invested in developing inhibitors of toxin adhesion that mimic the carbohydrate ligand, with

• particular emphasis on exploiting the multivalency of the toxin to enhance activity. In this review we introduce the structural features of the toxin that have guided the design of diverse inhibitors and summarise recent developments in the field. Keywords: carbohydrate; cholera; multivalency; toxin

• been drawn for the receptor binding to AB5 toxins; while some target on the individual binding sites, others are intended at designing multivalent ligands against the entire toxin B pentamer [6][30][31]. Monovalent receptor-binding inhibitors Bernardi and co-workers designed carbohydrate derivatives

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles

• Vivek Poonthiyil,
• Thisbe K. Lindhorst,
• Vladimir B. Golovko and
• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2

• many important biological processes, it is now well established that the binding interactions of a particular oligosaccharide, either with another carbohydrate or more commonly with carbohydrate-binding proteins (lectins), are generally weak. In order to augment these low affinity interactions

• , oligosaccharides usually bind lectins in a multivalent cooperative fashion. This avidity is significantly greater than the sum of the individual monomeric carbohydrate–protein interactions, and is sometimes referred to as the ‘cluster glycoside’ effect [6]. In order to study biological processes that involve these

• types of carbohydrate–protein interactions, it is therefore essential to present carbohydrates in a multivalent fashion. For that purpose, different scaffolds, such as peptides, proteins, lipids, and synthetic polymers, have all been used [7]. The search for better scaffolds for the presentation of

An efficient synthesis of 1,6-anhydro-N-acetylmuramic acid from N-acetylglucosamine

• Matthew B. Calvert,
• Christoph Mayer and
• Alexander Titz

Beilstein J. Org. Chem. 2017, 13, 2631–2636, doi:10.3762/bjoc.13.261

• cell wall recycling; carbohydrate synthesis; Introduction 1,6-Anhydro-N-acetylmuramic acid (AnhydroMurNAc, 1, Figure 1) and its derivatives (e.g., 2 and 3) are of great interest due to their integral role in bacterial cell wall recycling [1][2] and the induction of antibacterial resistance [3

What contributes to an effective mannose recognition domain?

• Christoph P. Sager,
• Deniz Eriş,
• Martin Smieško,
• Rachel Hevey and
• Beat Ernst

Beilstein J. Org. Chem. 2017, 13, 2584–2595, doi:10.3762/bjoc.13.255

• Christoph P. Sager Deniz Eris Martin Smiesko Rachel Hevey Beat Ernst Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, CH-4056 Basel, Switzerland 10.3762/bjoc.13.255 Abstract In general, carbohydrate–lectin interactions are characterized by high specificity but

• carbohydrate–lectin interactions of the innate immune system but also in bacterial adhesion, a process key for the bacterium’s survival. In an effort to better understand the particular characteristics, which contribute to a successful carbohydrate recognition domain, the mannose-binding sites of six C-type

• mammalian mannose-binding sites are in general flat and solvent exposed, the half-lives of carbohydrate–lectin complexes are rather short since water molecules can easily access and displace the ligand from the binding site. In contrast, the bacterial lectin FimH benefits from a deep mannose-binding site

Electron-deficient pyridinium salts/thiourea cooperative catalyzed O-glycosylation via activation of O-glycosyl trichloroacetimidate donors

• Mukta Shaw,
• Yogesh Kumar,
• Rima Thakur and
• Amit Kumar

Beilstein J. Org. Chem. 2017, 13, 2385–2395, doi:10.3762/bjoc.13.236

• past few decades [5][6][7][8][9][10]. However, the synthesis of fundamental glycosidic bonds with high efficiency and selectivity yet remains one of the major challenges for organic chemists, in particular, carbohydrate chemists. Nature extensively employs small organic molecules as catalysts for the

• , it is still uncommonly employed in the area of carbohydrate chemistry, especially for glycosylation reactions, due to the prerequisite of having both catalysts being compatible under the reaction conditions. The Schmidt group has successfully applied the synergistic catalysts (thiourea derivatives

• carbohydrate chemistry. It is pleasing to note that on reaction with partially protected acceptor 22 with glycosyl donors 1α and 7α under the optimized conditions lead to the regioisomeric products 23 and 24 [46][47] in moderate yields with good selectivity (Scheme 2). Plausible mechanism To confirm the

Homologated amino acids with three vicinal fluorines positioned along the backbone: development of a stereoselective synthesis

• Raju Cheerlavancha,
• Ahmed Ahmed,
• Yun Cheuk Leung,
• Aggie Lawer,
• Qing-Quan Liu,
• Marina Cagnes,
• Hee-Chan Jang,
• Xiang-Guo Hu and
• Luke Hunter

Beilstein J. Org. Chem. 2017, 13, 2316–2325, doi:10.3762/bjoc.13.228

• Raju Cheerlavancha Ahmed Ahmed Yun Cheuk Leung Aggie Lawer Qing-Quan Liu Marina Cagnes Hee-Chan Jang Xiang-Guo Hu Luke Hunter School of Chemistry, The University of New South Wales, Sydney NSW 2052, Australia National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• metal affinity chromatography (IMAC). Such types of solid phases were applied to enrich carbohydrate from extracts [61] or as chiral selectors immobilized on silica for chiral cation exchange chromatography [62] (Figure 4). Porphyrin tetra-functionalized with phosphonic acid groups was used as a

An efficient synthesis of a C₁₂-higher sugar aminoalditol

• Łukasz Szyszka,
• Anna Osuch-Kwiatkowska,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2017, 13, 2146–2152, doi:10.3762/bjoc.13.213

• with long chains are very interesting. However, the synthesis of this kind of molecules is a real challenge in carbohydrate chemistry. Very often reactions, which work well for ‘normal’ (C5–C7) sugars are not applicable for the elongated analogs [6][7]. Recently we have prepared such a derivative by

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• weaker as expected due to the dilution effect caused by the presence of the carbohydrate host, but in an expansion it is possible to discern the presence of almost all carbon resonances of fisetin, with exception of C8, which most likely overlaps with the signal of the C4 of γ-CD. Of note are two

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• needed [3]. However, this is hampered by the limited availability of complex glycans from nature. Thus, chemical synthesis is a powerful approach to provide much needed samples to enable biological studies [4]. Traditional carbohydrate synthesis is commonly carried out from the reducing end to the non

• , which has been covered in other reviews [23][42], has been applied to successful synthesis of a range of complex oligosaccharides including human milk oligosaccharides [45], an embryonic stem cell surface carbohydrate marker Lc4 [46], Globo-H hexasaccharide [47], and heparin-like oligosaccharides [48

• oligosaccharides including those containing both 1,2-cis and 1,2-trans linkages, branching sequences and sulfate esters. For example, a four component preactivation-based one-pot synthesis was designed to synthesize Globo-H, an important tumor-associated carbohydrate antigen (Scheme 18) [60]. Globo-H

Enzymatic separation of epimeric 4-C-hydroxymethylated furanosugars: Synthesis of bicyclic nucleosides

• Neha Rana,
• Manish Kumar,
• Vinod Khatri,
• Jyotirmoy Maity and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2017, 13, 2078–2086, doi:10.3762/bjoc.13.205

• of synthetic carbohydrate and nucleoside chemistry. Experimental The Candida antarctica lipase-B (CAL-B or Novozyme®-435) immobilized on polyacrylate was purchased from Sigma-Aldrich Co. (USA). Theremomyces lanuginosus lipase (Lipozyme TL IM) immobilized on silica was obtained as a gift from

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• Xiao G. Jia Alexei V. Demchenko Department of Chemistry and Biochemistry, University of Missouri – St. Louis, One University Blvd., 434 Benton Hall (MC27), St. Louis, MO 63121, USA 10.3762/bjoc.13.201 Abstract Carbohydrate oligomers remain challenging targets for chemists due to the requirement

Influence of the milling parameters on the nucleophilic substitution reaction of activated β-cyclodextrins

• László Jicsinszky,
• Kata Tuza,
• Giancarlo Cravotto,
• Andrea Porcheddu,
• Francesco Delogu and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 1893–1899, doi:10.3762/bjoc.13.184

• derivatization [8]. Although the preparation of carbohydrate-based complexes in a ball mill has been already reported [9][10][11], the use of mechanical activation for the chemical derivatization of CDs has been rather sporadic [12][13][14][15]. In this respect, it is worth noting that CDs exhibit a

• characteristic reactivity profile. Neither traditional synthetic routes nor a conventional carbohydrate activation methodology allow for CD derivatization. The major issues stem from the differing solubility of the reagents in organic solvents, meaning that high boiling polar solvents, such as DMF or DMSO, need

Enzymatic synthesis of glycosides: from natural O- and N-glycosides to rare C- and S-glycosides

• Jihen Ati,
• Pierre Lafite and
• Richard Daniellou

Beilstein J. Org. Chem. 2017, 13, 1857–1865, doi:10.3762/bjoc.13.180

• Jihen Ati Pierre Lafite Richard Daniellou ICOA UMR CNRS 7311, University of Orléans, rue de Chartres, BP 6759, 45067 Orléans cedex 2, France 10.3762/bjoc.13.180 Abstract Carbohydrate related enzymes, like glycosyltransferases and glycoside hydrolases, are nowadays more easily accessible and are

• this goal, the glycoscientists will have to collaborate strongly to obtain pure and well-defined glycoconjugates. Indeed, even if during the last century, the chemists have engaged great efforts to successfully develop efficient means of synthesis of carbohydrate derivatives, through the use of

• . Rational mutagenesis, directed evolution, or even de novo design have dramatically broaden the applicability of enzymes in biocatalysis [7]. In the glycochemistry field, a vast array of carbohydrate-metabolizing enzymes [8] has been used to synthesize glycosides, even using multiple enzymes systems

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

• the complete absence of protecting groups in an aqueous environment using 2-chloro-1,3-dimethylimidazolinium chloride (DMC) and a mild amine base (NEt3) (see chapter 4.1). 2.1.2 Glycosyltransferases: Glycosyltransferases (GTs) catalyze the transfer of a carbohydrate from an activated nucleotide

• major impetus for the progress in synthetic carbohydrate chemistry [41]. Also noteworthy is the fact that their conditions were applicable to multiple functional groups at C2, as their mechanistic proposal does not include an involvement of this carbon. However, the obvious drawback of this procedure is

• . What will certainly be interesting in the future if a more in depth mechanism can be discerned. 3.4 Transition metal-catalyzed glycosylation The metal-catalyzed activation of the anomeric center has been employed in carbohydrate chemistry for many decades and continues to be a very rapidly expanding

Aqueous semisynthesis of C-glycoside glycamines from agarose

• Juliana C. Cunico Dallagnol,
• Alexandre Orsato,
• Diogo R. B. Ducatti,
• Miguel D. Noseda,
• Maria Eugênia R. Duarte and
• Alan G. Gonçalves

Beilstein J. Org. Chem. 2017, 13, 1222–1229, doi:10.3762/bjoc.13.121

• . The unpolymerized product shows AnGal as a C-threofuranose motif [7] (see agarobiose, 2, Scheme 1) and because C-glycosides are useful moieties for chemical synthesis and medicinal chemistry, agarose hydrolysis products can be considered interesting carbohydrate-based building blocks [8] to be

• laboratories and will be subject of a forthcoming publication. Experimental Reductive amination general procedure Carbohydrate aldehyde hydrate (1.5 mmol) was dissolved in water (25 mL) then ammonium salts (40 equiv) or methylamine hydrochloride (30 equiv) or dimethylamine hydrochloride (8.5 equiv) were added

Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience

• Serge Pérez and
• Daniele de Sanctis

Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114

• molecules and macromolecules that form the collection of substrates investigated by glycoscience. The present review illustrates how synchrotron-based experiments have contributed to our understanding in the field of structural glycobiology. Structural characterization of protein–carbohydrate interactions

• of polysaccharides. Insights into the kinetics of catalytic events observed in the crystalline state are also presented as well as some aspects of structure determination of protein in solution. Keywords: antibodies; carbohydrate binding domains; cellulose; glycosaminoglycans; glycolipids; glycosyl

• to some key areas of glycoscience potentially of interest to the growing number of non-specialist users. Structural characterization of protein–carbohydrate interactions are covered as well as some involving glycolipids and colloids and the structure and architecture of polysaccharides. Insights into

Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

• Adesh Kumar Singh,
• Varsha Tiwari,
• Kunj Bihari Mishra,
• Surabhi Gupta and
• Jeyakumar Kandasamy

Beilstein J. Org. Chem. 2017, 13, 1139–1144, doi:10.3762/bjoc.13.113

• role in carbohydrate synthesis. Thioglycosides, glycosyl sulfoxides and sulfones have been widely used as glycosyl donors in oligosaccharide synthesis which can be activated under mild reaction conditions [5][6][7][8][9][10]. Glycosyl sulfoxide donors usually provide excellent anomeric selectivity

Correction: Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 1136–1138, doi:10.3762/bjoc.13.112

• residues in Scheme 15; the corrected scheme (Scheme 2) is shown below: The carbohydrate polymers in Schemes 20 and 22 were depicted as poly-peroxide with one oxygen atom too many in the repeating unit, repectively; the corrected schemes (Scheme 3 and Scheme 4) are shown below: Corrected Scheme 9 of the