Biosynthesis of rare hexoses using microorganisms and related enzymes

• Zijie Li,
• Yahui Gao,
• Hideki Nakanishi,
• Xiaodong Gao and
• Li Cai

Beilstein J. Org. Chem. 2013, 9, 2434–2445, doi:10.3762/bjoc.9.281

• pharmaceutical and nutrition industry [4]. In recent years, the interest in rare carbohydrates and the nucleosides (e.g. L-nucleoside analogues) derived from them has substantially increased in medicine because these molecules are potential candidates of anticancer and antiviral drugs [4][5][6]. Unfortunately

• performed in a one-pot fashion or with purification after each step. III. Biosynthesis of rare sugar alcohols (hexitols) Sugar alcohols are mainly derived from pentoses and hexoses. They are hydrogenated form of carbohydrates, in which the carbonyl group is reduced. Their flavor is like sucrose but they

• -talitol catalyzed by a halotolerant yeast strain Candida famata R28 could be significantly increased in the presence of various carbohydrates such as erythritol, D-sorbitol, ribitol and glycerol in the reaction mixture [100]. The faster consumption of the substrate could be explained by the in situ NADH

Synthesis of enantiopure sugar-decorated six-armed triptycene derivatives

• Paola Bonaccorsi,
• Maria Luisa Di Gioia,
• Antonella Leggio,
• Lucio Minuti,
• Teresa Papalia,
• Carlo Siciliano,
• Andrea Temperini and
• Anna Barattucci

Beilstein J. Org. Chem. 2013, 9, 2410–2416, doi:10.3762/bjoc.9.278

• controlled by recognition phenomena between carbohydrates and proteins. Generally, individual sugar units exhibit weak binding affinities to complementary proteins, while systems that incorporate several carbohydrate units, attached to an appropriate scaffold or self-assembled in nanoparticles, lead to

Synthesis of homo- and heteromultivalent carbohydrate-functionalized oligo(amidoamines) using novel glyco-building blocks

• Felix Wojcik,
• Sinaida Lel,
• Alexander G. O’Brien,
• Peter H. Seeberger and
• Laura Hartmann

Beilstein J. Org. Chem. 2013, 9, 2395–2403, doi:10.3762/bjoc.9.276

• the straightforward synthesis of multivalent glycoligands with full control over monomer sequence and functionalization pattern. We demonstrate the potential of this building-block approach by synthesizing oligomers with different numbers and spacing of carbohydrates and also show the feasibility of

A one-pot synthesis of 3-trifluoromethyl-2-isoxazolines from trifluoromethyl aldoxime

• Raoni S. B. Gonçalves,
• Michael Dos Santos,
• Guillaume Bernadat,
• Danièle Bonnet-Delpon and
• Benoit Crousse

Beilstein J. Org. Chem. 2013, 9, 2387–2394, doi:10.3762/bjoc.9.275

• causes remarkable changes of their physicochemical properties, which allows the development of substances with improved pharmacological characteristics. Some examples are the synthesis of modified amino acids and peptides, carbohydrates, natural products and the development of more selective enzyme

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• thiazolidinedione class of type-2 diabetes drugs (Figure 1). These pharmaceutical agents act as binders to the peroxisome proliferator-activated receptors that upon activation migrate to the DNA to regulate the transcription of specific genes which control the metabolism of carbohydrates and fatty acids. The

Flexible synthesis of anthracycline aglycone mimics via domino carbopalladation reactions

• Markus Leibeling and
• Daniel B. Werz

Beilstein J. Org. Chem. 2013, 9, 2194–2201, doi:10.3762/bjoc.9.258

• approach and subsequent ring closure. During this process two of the four rings of the anthracycline scaffold are formed. Differently substituted carbohydrates and dialkyne chains serve as versatile and simple starting materials for the reaction sequence. Diverse building blocks lead to a variety of

• different products and a broad range of structural diversity. Keywords: anthracyclines; carbohydrates; carbopalladation; catalysis; domino reaction; natural products; Introduction Anthracyclines are a widespread class of natural products which belong to the group of aromatic polyketides [1]. Most of them

• substitution pattern of the D-ring bares most of the functionalities, i.e., a secondary and a tertiary alcohol, the former of which is commonly glycosylated with 2,6-dideoxy sugars (Figure 1) [3]. These carbohydrates are of highest importance for the biological activity of anthracyclines and bind to the minor

Gold-catalyzed glycosidation for the synthesis of trisaccharides by applying the armed–disarmed strategy

• Abhijeet K. Kayastha and
• Srinivas Hotha

Beilstein J. Org. Chem. 2013, 9, 2147–2155, doi:10.3762/bjoc.9.252

• carbohydrate chemistry was first reported for the oxidation of alcohols [11][12][13][14][15][16]. However, until recently these catalysts were scarcely applied. Glycosidation is one of the key reactions in chemistry of carbohydrates, in which a nucleophile attaches to a saccharide to form a glycoside. In this

Flow synthesis of a versatile fructosamine mimic and quenching studies of a fructose transport probe

• Matthew B. Plutschack,
• D. Tyler McQuade,
• Giulio Valenti and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 2022–2027, doi:10.3762/bjoc.9.238

• in fructose exhibit increased rates of metabolic disorders and aggressive cancers [1][2]. Since the landmark reports from Warburg [3], researchers have recognized that cancer cells/tissues consume more carbohydrates than normal tissues, fueling rapid growth and proliferation [4]. While cancer cells

A versatile and efficient approach for the synthesis of chiral 1,3-nitroamines and 1,3-diamines via conjugate addition to new (S,E)-γ-aminated nitroalkenes derived from L-α-amino acids

• Vera Lúcia Patrocinio Pereira,
• André Luiz da Silva Moura,
• Daniel Pais Pires Vieira,
• Leandro Lara de Carvalho,
• Eliz Regina Bueno Torres and
• Jeronimo da Silva Costa

Beilstein J. Org. Chem. 2013, 9, 832–837, doi:10.3762/bjoc.9.95

• combinations of both [42][43][44]. Nonetheless, the use of chiral nitroalkenes bearing a stereogenic center in the γ-position in nonracemic diastereoselective syntheses ("chiron" approach [45]) is less frequent in the literature. Notably, chiral nitroalkenes derived from carbohydrates [46][47][48][49][50] have

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• of β-elimination. This constitutes a tremendous synthetic asset and explains the popularity and importance of radical-based methods for the manipulation and modification of oxygen-rich compounds such as carbohydrates and cyclitols. It is, however, possible to transform an alcohol into a leaving group

Synthesis of meso-substituted dihydro-1,3-oxazinoporphyrins

• Satyasheel Sharma and
• Mahendra Nath

Beilstein J. Org. Chem. 2013, 9, 496–502, doi:10.3762/bjoc.9.53

• derived from porphyrins [11][12]. Previously, a large number of these molecules have been synthesized by the coupling of diverse pharmaceutically important moieties, such as carbohydrates [13][14][15], amino acid residues [16][17][18][19], steroids [20][21], glycosides [22][23][24], nitroxyl derivatives

Efficient synthesis of phenylene-ethynylene rods and their use as rigid spacers in divalent inhibitors

• Francesca Pertici,
• Norbert Varga,
• Arnoud van Duijn,
• Matias Rey-Carrizo,
• Anna Bernardi and
• Roland J. Pieters

Beilstein J. Org. Chem. 2013, 9, 215–222, doi:10.3762/bjoc.9.25

• phenylene units. Preliminary applications of these rods in divalent systems are shown. Inhibition studies with Pseudomonas Aeruginosa lectin LecA showed that the rigid spacer proved greatly beneficial for the inhibitory potency. Keywords: multivalent carbohydrates; LecA inhibition; phenylene ethynylene

• obtained after deprotection of the alkyne moieties with K2CO3. Preliminary application As part of our program on bacterial adhesion inhibition by multivalent carbohydrates, the bacterial lectin LecA, a virulence factor of the problematic pathogen Pseudomonas aeruginosa is a target of interest [30][31

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

• cases. The effect of triethylsilane and 10% Pd/C on the removal of benzylidene acetal is presented in Table 1. The noteworthy features of the reaction condition are: (a) neutral conditions; (b) compatibility with a large number of functional groups used in the protection of carbohydrates (e.g., acetyl

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

• ; glucosylgalactofuranose; glycosylaldonolactone; Penicillium varians; varianose; Introduction Carbohydrates are involved in a wide range of biological processes; they play important roles in host–pathogen interactions and in the immune response, where protein–glycan interactions mediate a variety of biological processes

• , including cell trafficking, activation, differentiation and survival [1][2]. The variety and distinctive chemical properties of carbohydrates make them ideal units of condensed information, as variability is achieved not only in the glycan sequence but also in their spatial distribution. As a result

Multivalent display of the antimicrobial peptides BP100 and BP143

• Imma Güell,
• Rafael Ferre,
• Kasper K. Sørensen,
• Esther Badosa,
• Iteng Ng-Choi,
• Emilio Montesinos,
• Eduard Bardají,
• Lidia Feliu,
• Knud J. Jensen and
• Marta Planas

Beilstein J. Org. Chem. 2012, 8, 2106–2117, doi:10.3762/bjoc.8.237

• -1871 Frederiksberg, Denmark Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-CeRTA, University of Girona, Campus Montilivi, 17071 Girona, Spain 10.3762/bjoc.8.237 Abstract Carbohydrates are considered as promising templates for the display of multiple copies of

• [18][19][20][21][22]. Carbohydrates are promising candidates as templates for the display of functional groups due to their inherent multifunctionality, the relative rigidity of their structure, and the ease of regioselective chemical manipulation [23][24][25]. Jensen and co-workers reported the

Asymmetric desymmetrization of meso-diols by C₂-symmetric chiral 4-pyrrolidinopyridines

• Hartmut Schedel,
• Keizo Kan,
• Yoshihiro Ueda,
• Kenji Mishiro,
• Keisuke Yoshida,
• Takumi Furuta and
• Takeo Kawabata

Beilstein J. Org. Chem. 2012, 8, 1778–1787, doi:10.3762/bjoc.8.203

• pyrrolidine ring such as 3 were prepared from trans-4-hydroxy-L-proline. These catalysts were found to be moderately effective for the asymmetric desymmetrization of meso-diols [11]. C2-Symmetric PPY-catalyst 4 was found to be effective for the chemo- and regioselective acylation of carbohydrates [12][14][16

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

• arginine [11]. Tachibana et al. summarized the essential properties of AFGPs displaying significant antifreeze activity: The disaccharide must be α-glycosidically attached to every threonine; the acetylamino moiety has to be present at the C2 position; the carbohydrates must be galacto-configured; and the

• assembly of the glycopeptides the acetate protecting groups of the carbohydrates were cleaved with 5% hydrazine in DMF followed by the cleavage of the peptide from the resin with 2% aqueous TFA. Subsequently, the peptides were precipitated with cold diethyl ether and the solid residues were purified by

The Amadori rearrangement as glycoconjugation method: Synthesis of non-natural C-glycosyl type glycoconjugates

• Katharina Gallas,
• Gerit Pototschnig,
• Florian Adanitsch,
• Arnold E. Stütz and
• Tanja M. Wrodnigg

Beilstein J. Org. Chem. 2012, 8, 1619–1629, doi:10.3762/bjoc.8.185

• communication. In order to investigate and elucidate their many functions, reliable synthetic methods for the conjugation of carbohydrates to biomolecules are of crucial importance [2]. Several ligation strategies are described in the literature, such as chemical ligation [3], conjugation by means of click

• surfaces (glycosylated surfaces, e.g., “glyco-chips”, gold, polystyrene plates, glass, nanoparticles), or labelling and imaging of carbohydrates (fluorescence markers, biotin, photolabelling) [27][28]. Herein we describe the application of the Amadori rearrangement as a key step for the synthesis of non

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

• multivalent interaction with ConA, and the most efficient interaction (i.e., fastest agglutination at lowest concentration) was observed for mannose–adamantane conjugates, in which both the cyclodextrin–adamantane and the lectin–mannose interaction is inherently multivalent. Keywords: carbohydrates

• ; cyclodextrins; lectins; molecular recognition; multivalency; vesicles; Introduction The surface modification of materials with carbohydrates has attracted much attention due to the fact that such materials can be compared to and compatible with the cell surface [1]. The “glycocalyx” is a dense layer on the

• 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

Recyclable fluorous cinchona alkaloid ester as a chiral promoter for asymmetric fluorination of β-ketoesters

• Wen-Bin Yi,
• Xin Huang,
• Zijuan Zhang,
• Dian-Rong Zhu,
• Chun Cai and
• Wei Zhang

Beilstein J. Org. Chem. 2012, 8, 1233–1240, doi:10.3762/bjoc.8.138

• . Introducing one or a few fluorine atoms to biologically interesting molecules can significantly change the physical, chemical and biological properties [1][2]. The significant amount of publications on fluorinated small molecules, amino acids, carbohydrates, steroids and nucleosides indicates that

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

• modifying this residue, particularly at O-4, may lead to the complete loss of this cross-reactivity [15]. Currently, it is not known what the reason for this observed loss of binding is, since the binding affinities between proteins and carbohydrates are the result of a combination of factors [25][26][27

Synthesis and structure of tricarbonyl(η⁶-arene)chromium complexes of phenyl and benzyl D-glycopyranosides

• Thomas Ziegler and
• Ulrich Heber

Beilstein J. Org. Chem. 2012, 8, 1059–1070, doi:10.3762/bjoc.8.118

• hydrogen bonds. Keywords: aryl glycosides; carbohydrates; transition-metal complex; tricarbonyl(arene)chromium; Introduction In 1957, Fischer and Öfele published the preparation of tricarbonyl(η6-benzene)chromium, which was the first arene tricarbonylchromium complex [1]. Since then, a plethora of

The use of glycoinformatics in glycochemistry

• Thomas Lütteke

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

• that can be of use to glycobiologists, but also to chemists who work on the synthesis or analysis of carbohydrates. This article gives an overview of existing glyco-specific databases and tools, with a focus on their application to glycochemistry: Databases can provide information on candidate glycan

• structures for synthesis, or on glyco-enzymes that can be used to synthesize carbohydrates. Statistical analyses of glycan databases help to plan glycan synthesis experiments. 3D-Structural data of protein–carbohydrate complexes are used in targeted drug design, and tools to support glycan structure analysis

• aid with quality control. Specific problems of glycoinformatics compared to bioinformatics for genomics or proteomics, especially concerning integration and long-term maintenance of the existing glycan databases, are also discussed. Keywords: carbohydrates; databases; glycomics; software

High-affinity multivalent wheat germ agglutinin ligands by one-pot click reaction

• Henning S. G. Beckmann,
• Heiko M. Möller and
• Valentin Wittmann

Beilstein J. Org. Chem. 2012, 8, 819–826, doi:10.3762/bjoc.8.91

• enhancements of the multivalent ligands with their ability to bind to the protein in a chelating mode. The best WGA ligand is a trivalent cluster with an IC50 value of 220 nM. Calculated per mol of contained chitobiose, this is the best WGA ligand known so far. Keywords: carbohydrates; click chemistry

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

• mutant or a high-mannose oxazoline donor and an Endo-A mutant, two different homogenous glycoproteins 40 and 41 were formed (Scheme 7) [87]. Glycopeptide binding events Carbohydrates on proteins and lipids play critical roles in cell–cell and cell–external-agent binding events. Efforts in the preparation

• of diverse carbohydrate structures immobilized in a microarray format have made carbohydrates accessible for numerous functional studies of protein-binding recognition [90][91][92]. In addition to the glycan structure, multivalency and orientation are important for the presentation of glycan ligands