Are D-manno-configured Amadori products ligands of the bacterial lectin FimH?

• Tobias-Elias Gloe,
• Insa Stamer,
• Cornelia Hojnik,
• Tanja M. Wrodnigg and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 1096–1104, doi:10.3762/bjoc.11.123

• potential as therapeutics and as tools for mechanistic studies in biology. This is because they are not sensitive towards enzymatic hydrolysis such as in physiological environment, in contrast to the naturally occurring O- and N-glycosides. With respect to our long-lasting interest in the design and

• predictions made by molecular docking, inhibition–adhesion studies using type 1-fimbriated fluorescent E. coli were performed [30]. Accordingly, the manno-configured glycosides 9 and 10 were used as inhibitors of FimH-mediated bacterial adhesion to mannan employing a microtiter plate format and GFP

N-Alkyl derivatives of diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside; synthesis and antimicrobial activity

• Agata Walczewska,
• Daria Grzywacz,
• Dorota Bednarczyk,
• Małgorzata Dawgul,
• Andrzej Nowacki,
• Wojciech Kamysz,
• Beata Liberek and
• Henryk Myszka

Beilstein J. Org. Chem. 2015, 11, 869–874, doi:10.3762/bjoc.11.97

• . Keywords: antimicrobial activities; D-glucosamine; diosgenin glycosylation; N-alkylation; Introduction Saponins are a group of steroid or triterpenoid glycosides, widely distributed in the plant kingdom [1]. Saponins are characteristic by their foaming properties in aqueous solution, causing them to be

• saponins have been investigated [12][13][14][15][16][17][18][19][20][21][22] as well as the evaluation of their antitumor activities [23][24][25][26][27]. Naturally-occurring diosgenyl glycosides are the most abundant steroidal saponins. They have been continuously synthesized [28][29][30][31][32] and

• their cardiovascular, antifungal, anticancer [33][34][35][36] and antithrombotic activities [37] have been investigated. Gelation ability of the pentose derivatized diosgenyl saponins have also been reported [38]. In the family of diosgenyl β-glycosides D-glucopyranose is the first sugar attached to the

Synthesis of carbohydrate-scaffolded thymine glycoconjugates to organize multivalency

• Anna K. Ciuk and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 668–674, doi:10.3762/bjoc.11.75

• , it is known that the thymine heterocycle can be easily N3-alkylated with, for example, bromoalkyl glycosides. This reaction can be used to install specific sugar moieties for biological recognition [5]. Hence, thymine was employed as the photosensitive control element, a functionalized mannoside was

Synthesis of 1,2-cis-2-C-branched aryl-C-glucosides via desulfurization of carbohydrate based hemithioacetals

• Henok H. Kinfe,
• Fanuel M. Mebrahtu,
• Mandlenkosi M. Manana,
• Kagiso Madumo and
• Mokela S. Sokamisa

Beilstein J. Org. Chem. 2015, 11, 583–588, doi:10.3762/bjoc.11.64

• biologically important compounds. Although the synthesis of such carbohydrate derivatives is extensively studied, the synthesis of 1,2-cis-2-C-branched C-, S-, and N-glycosides is less explored. In this article a synthetic strategy for the synthesis of 1,2-cis-2-C-branched-aryl-C-glucosides is reported via a

• stereospecific preparation of 2,3-unsaturated-aryl-C-glycosides (Ferrier products). Keywords: aryl-C-glucoside; desulfurization; Ferrier product; hemithioacetal; Introduction 1-C (C-glycosides) and 2-C-branched carbohydrates are important carbohydrate analogues which have found wide application in

• glycochemistry and medicinal chemistry [1][2][3][4][5]. C-Glycosides, especially aryl-C-glycosides, are the main structural features of a number of biologically active natural products such as pluramycins (antibacterial and antitumor activities), angucyclines (antibacterial, antitumor activities, and inhibitors

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45

• electrochemical acetoxylation of cholesterol at the allylic position. Direct anodic oxidation of cholesterol in dichloromethane. A plausible mechanism of the electrochemical oxidation of cholesterol in dichloromethane. The electrochemical formation of glycosides and glycoconjugates. Efficient electrochemical

Photovoltaic-driven organic electrosynthesis and efforts toward more sustainable oxidation reactions

• Bichlien H. Nguyen,
• Robert J. Perkins,
• Jake A. Smith and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2015, 11, 280–287, doi:10.3762/bjoc.11.32

• , commercially available, photovoltaic cell. Electrochemical recycling of a chemical oxidant. Examples of solar-driven direct electrochemical oxidations. Overoxidation of dithioketal. Examples of solar-driven, indirect electrochemical oxidations. Solar-driven synthesis of C-glycosides. Solar-driven oxidative

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• flavonoids fisetin (67) and quercetin (68) belong to the flavonol subgroup that exhibit a double bond between C-2/C-3 and a hydroxy group at C-3. Flavonols are the most abundant flavonoid subtype in plants and commonly occur as glycosides. Nevertheless, pharmacological testing was historically concentrated

• on the investigation of the aglycones. Although this has been often criticized, it is most likely an important aspect with regard to flavonoid metabolism. It has been shown that the flavonoid glycosides are not absorbed after oral intake but are cleaved by lactase-phlorizin hydrolase and absorbed as

• that fisetin inhibits MMPs and reduces tumor-cell invasiveness and endothelial cell tube formation. Together with kaempferol, quercetin is the most abundant aglycone in flavonol glycosides. Quercetin glycosides occur in higher concentrations in onions, red wine, and green tea and in various medicinal

3α,5α-Cyclocholestan-6β-yl ethers as donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates

• Aneta M. Tomkiel,
• Adam Biedrzycki,
• Jolanta Płoszyńska,
• Dorota Naróg,
• Andrzej Sobkowiak and
• Jacek W. Morzycki

Beilstein J. Org. Chem. 2015, 11, 162–168, doi:10.3762/bjoc.11.16

• derivatives show similar reactivities to those of previously studied 3α,5α-cyclocholestan-6β-thioethers. Keywords: cholesterol; electrochemical oxidation; glycosylation; i-cholesteryl ethers; i-steroids; Introduction We have recently elaborated an electrochemical method for the preparation of glycosides and

• glycoconjugates from 3β-hydroxy-Δ5-steroids (sterols). The method consists of electrooxidation of a proper cholesterol derivative in the presence of an unactivated sugar with a free hydroxy group at the anomeric position (formation of glycosides) or at any other position (preferentially a primary position) that

Synthesis of divalent ligands of β-thio- and β-N-galactopyranosides and related lactosides and their evaluation as substrates and inhibitors of Trypanosoma cruzi trans-sialidase

• María Emilia Cano,
• Rosalía Agusti,
• Alejandro J. Cagnoni,
• María Florencia Tesoriero,
• José Kovensky,
• María Laura Uhrig and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 3073–3086, doi:10.3762/bjoc.10.324

• ’-sialyllactose as sialic acid donor, in the presence of the acceptor having βGalp non reducing ends. The products were analyzed by high performance anion exchange chromatography with pulse amperometric detection (HPAEC-PAD). The ability of the different S-linked and N-linked glycosides to inhibit the sialic acid

• ). Again, they showed very similar NMR spectra. For example, in the 13C spectra the anomeric signals appeared at ca. 101 ppm, 91–97 ppm and 82 ppm, corresponding respectively to the terminal βGal, αGlc from the scaffold and the βSGlc residues. N-linked precursors 10, 12, 15 and 17 and S-glycosides 19 and

• infection process. Experimental The synthetic general methods are described in the Supporting Information File 1. Synthesis of compounds 10, 12, 15, 17, 20 and 22. General procedure for the click reaction [43][44]. The corresponding azido-saccharides 9 or 14 [34] (0.20 mmol) and N-linked glycosides 3 or 6

Galactan synthesis in a single step via oligomerization of monosaccharides

• Marius Dräger and
• Amit Basu

Beilstein J. Org. Chem. 2014, 10, 2658–2663, doi:10.3762/bjoc.10.279

• separable oligosaccharide products that are functionalized as glycosides at their reducing termini [16]. We report here the oligomerization of a galactosyl donor in the presence of an initiating alcohol to prepare galactans ranging from mono- to pentasaccharides with concomitant control of stereochemistry

A general metal-free approach for the stereoselective synthesis of C-glycals from unactivated alkynes

• Shekaraiah Devari,
• Manjeet Kumar,
• Ramesh Deshidi,
• Masood Rizvi and
• Bhahwal Ali Shah

Beilstein J. Org. Chem. 2014, 10, 2649–2653, doi:10.3762/bjoc.10.277

• , India 10.3762/bjoc.10.277 Abstract A novel metal-free strategy for a rapid and α-selctive C-alkynylation of glycals was developed. The reaction utilizes TMSOTf as a promoter to generate in situ trimethylsilylacetylene for C-alkynylation. Thanks to this methodology, we can access C-glycosides in a

• single step from a variety of acetylenes , i.e., arylacetylenes and most importantly aliphatic alkynes. Keywords: α-selective; C-alkynylation; glycal; metal free; TMSOTf; Introduction C-Glycosides represent an important class of carbohydrate mimics, owing to their presence in a large number of

• groups, while the stereoelectronic control allows the α-pseudo-axial orbital to form the bond [35]. Conclusion In conclusion, we developed a highly efficient and α-selective method for the synthesis of alkynyl glycosides from virtually any alkyne, that is, aliphatic and aromatic. To the best of our

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

• aromatic backbone building blocks 7 and 9. Synthesis of dimers 17, 20, 22 and 24. Synthesis of glycosides 11 and 12. Synthesis of glycopeptide building blocks 1 and 2. Supporting Information Supporting Information File 387: Experimental data. Supporting Information File 388: NMR Spectra. Acknowledgements

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• inflammation and traumatic bleeding. The leaves and stems of this plant contain oleoside-type secoiridoid glucosides with structurally interesting tetrasubstituted cyclopentanoid monoterpene units [116]. Two representative examples of these glycosides are nudifloside A (151) and D (13), which share a common

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• . Unnatural divalent rigid p-terphenyl-linked C-aryl glycosides with 2.0 nm dimension are available using Suzuki cross-couplings. The key compound, a p-bromophenyl-substituted 1,2-oxazine, was prepared by a stereoselective [3 + 3]-cyclization of a D-isoascorbic acid-derived (Z)-nitrone and lithiated TMSE

• -glycosides which possess structural and functional aspects of the corresponding carbohydrates, these disadvantages can be overcome, resulting in an improved bioavailability, higher affinities and improved selectivities [8][9][10][11][12][13]. Recent results indicate that divalent rigid carbohydrate

• to heat, air and moisture compared to other organometallic reagents [21]. Up to now there are not many examples of nanorod-like carbohydrate dimers with aryl-linked divalent glycosides. A mannopyranoside dimer was generated by a palladium-catalyzed Ullmann-type reductive homocoupling [22] and

The chemoenzymatic synthesis of clofarabine and related 2′-deoxyfluoroarabinosyl nucleosides: the electronic and stereochemical factors determining substrate recognition by E. coli nucleoside phosphorylases

• Ilja V. Fateev,
• Konstantin V. Antonov,
• Irina D. Konstantinova,
• Tatyana I. Muravyova,
• Frank Seela,
• Roman S. Esipov,
• Anatoly I. Miroshnikov and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2014, 10, 1657–1669, doi:10.3762/bjoc.10.173

• formation of the α/β mixtures of N-9 and N-7 glycosides (cf. [17]). Despite the detailed analysis and optimization of the clofarabine process [12][13] and the bulk production of the protected nucleoside glycon 9 by chemists at Eli Lilly and Co. [18] this chemical synthesis is connected with the use of great

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

• the silica gel plate. The addition of simple alcohols or partially protected sugars as acceptors and EtN(iPr)2 as an acid scavenger led to the complete consumption of both compounds and afforded the corresponding glycosides (Scheme 2) [32]. With an excess of TMSI, a third product (Rf = 0.62) was

Synthesis and solvodynamic diameter measurements of closely related mannodendrimers for the study of multivalent carbohydrate–protein interactions

• Yoann M. Chabre,
• Alex Papadopoulos,
• Alexandre A. Arnold and
• René Roy

Beilstein J. Org. Chem. 2014, 10, 1524–1535, doi:10.3762/bjoc.10.157

• quantitative structure–activity relationships (QSARs). In most of the studies related to aglycon modifications, it was concluded that aromatic glycosides possessed improved binding properties due to the ubiquitous presence of aromatic amino acids in the cognate binding sites [23][24][25]. This is also

Multichromophoric sugar for fluorescence photoswitching

• Stéphane Maisonneuve,
• Rémi Métivier,
• Pei Yu,
• Keitaro Nakatani and
• Juan Xie

Beilstein J. Org. Chem. 2014, 10, 1471–1481, doi:10.3762/bjoc.10.151

• could lead to a better ON vs OFF fluorescence contrast. By a careful molecular engineering, combining photophysical analysis and synthetic work, we are endeavoring to tune optimally the fluorophore/photochrome ratio. Glycosides, and more generally sugar molecules, may further provide appropriate

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

• mannose to PEI via a PEG chain spacer (Figure 3B). This system was used to deliver small interfering RNA (siRNA) into a murine macrophage cell line [44]. Mannose residues as their 2-aminoethyl glycosides were attached by reductive amination to the surface of copolymer micelles of PEG with poly-ε

• -caprolactone for targeting dendritic cells and macrophages (Figure 4) [45] Both mannose and galactose were attached to PEGylated nanoparticles by click-chemistry between their propargyl glycosides and a gold nanoparticles derivatized with an azide-functionalized PEG [46]. Also, several unprotected carbohydrate

Molecular recognition of surface-immobilized carbohydrates by a synthetic lectin

• Melanie Rauschenberg,
• Eva-Corrina Fritz,
• Christian Schulz,
• Tobias Kaufmann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 1354–1364, doi:10.3762/bjoc.10.138

• ]. Our group has shown that also simple carbohydrate microarrays can be conveniently prepared by μCP if reactive glycosides are printed on a suitable target self-assembled monolayer (SAM) [31][32]. Amongst others, we reported carbohydrate microarrays fabricated by cycloaddition of alkynes on azide

• HisHis towards immobilized NANA in comparison with the glycosides of glucose (Glc), galactose (Gal) and mannose (Man) (Figure 1). In this study, we exploit the epoxide ring opening reaction of amine-tethered carbohydrates on epoxide-terminated SAMs [42] to print carbohydrate microarrays on silicon and

• , Man, see Figure 1) were selected for the fabrication of carbohydrate arrays. To provide carbohydrate inks suitable for microcontact printing (µCP), NANA was conjugated via its C1 carboxylic acid moiety, whereas the other carbohydrates were conjugates as β-glycosides (Glc, Gal) and α-glycosides (Man

Design and synthesis of multivalent neoglycoconjugates by click conjugations

• Feiqing Ding,
• Li Ji,
• Ronny William,
• Hua Chai and
• Xue-Wei Liu

Beilstein J. Org. Chem. 2014, 10, 1325–1332, doi:10.3762/bjoc.10.134

• different substituent groups (3a–3e) with α-propargyl 3-tosylamino-2,3-dideoxy glycosides 2 afforded the corresponding 3-tosylamino-2,3-dideoxyneoglycoconjugates (4a–4h) in good to excellent yields with exclusive anomeric selectivity (Table 3, entries 1–8). This encouraging result prompted us to apply these

cis–trans Isomerization of silybins A and B

• Michaela Novotná,
• Radek Gažák,
• David Biedermann,
• Florent Di Meo,
• Petr Marhol,
• Marek Kuzma,
• Lucie Bednárová,
• Kateřina Fuksová,
• Patrick Trouillas and
• Vladimír Křen

Beilstein J. Org. Chem. 2014, 10, 1047–1063, doi:10.3762/bjoc.10.105

• (or 10 from 1b) on silica gel was not feasible, analogous to the preparative separation of silybin stereoisomers 1a and 1b (Figure 1), which was a challenge for several decades. It was accomplished as the separation of the respective silybin glycosides for the first time [13][14], later by HPLC [3

• -dihydroquercetin-3-α-L-rhamnopyranoside (pyridine; aqueous solution), was reported earlier [30][31][32][33]. The thermal or enzymatic rearrangement of taxifolin to alphitonin yielded four taxifolin isomers [34]. With flavanonols (3-O-glycosides or the respective aglycons), isomerization can be explained by the

Efficient carbon-Ferrier rearrangement on glycals mediated by ceric ammonium nitrate: Application to the synthesis of 2-deoxy-2-amino-C-glycoside

• Alafia A. Ansari,
• Y. Suman Reddy and
• Yashwant D. Vankar

Beilstein J. Org. Chem. 2014, 10, 300–306, doi:10.3762/bjoc.10.27

• -glycosides; carbon-Ferrier rearrangement; ceric ammonium nitrate; 2-deoxy-2-aminoglycosides; Overman rearrangement; Introduction The growing significance of C-glycosides can be attributed to their potential use as inhibitors of carbohydrate-processing enzymes [1][2][3], their extraordinary stability

• compared to O-glycosides, and their widespread applicability as intermediates in the synthesis of biologically important molecules [4][5][6][7][8]. C-glycosides are also subunits of several biologically active natural products [9][10][11]. Consequently, numerous reports are available in literature on the

• synthesis of C-glycosides [12][13][14]. Among these, the Ferrier rearrangement [15] of glycals with protic acids [5][16][17] or Lewis acids [18][19][20][21][22] and carbon nucleophiles such as allylsilanes [23], silylacetylenes [24], silyl enol ethers [25], olefins [26], and organozinc reagents [27] has

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

• rare sugar [25]. More interestingly, D-psicose has also been used to prepare several D-psicose containing disaccharides, aiming to learn the function of the rare sugar containing oligosaccharides and glycosides [27]. D-Psicose can be prepared through the epimerization of D-fructose at C-3 catalyzed by

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

• established conditions (30 min; 1.5 equiv thioglycoside; 0.1 M). Although the reactivity of aminoglycosides 5 and 6 is in the same range as that of glycosides 2–4, we chose a higher excess of thiol component (2 equiv) for the production of glycosylated building blocks 11 and 12, resulting in >95% conversion