Automated solid-phase synthesis of oligosaccharides containing sialic acids

• Chian-Hui Lai,
• Heung Sik Hahm,
• Chien-Fu Liang and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2015, 11, 617–621, doi:10.3762/bjoc.11.69

• synthesis in the future as well. The tumor associated sTn carbohydrate antigen (Neu5Ac-α(2,6)GalNAc-α(1,1)linker) disaccharide 17, that resembles the sTn antigen glycan framework (Neu5Ac-α(2,6)GalNAc-α(1,1)Ser/Thr) was synthesized. In order to install the cis-glycoside formed by the union of the

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

• to C-glycosides are 2-C-branched carbohydrates which are employed as bioisosters of the natural 2-acetamido glycoside derivatives. Gammon et al. prepared a series of 2-C-branched carbohydrates as potential inhibitors of enzymes implicated in the biosynthesis of mycothiol, Mycobacterium tuberculosis’s

• and 5a’ was treated with a catalytic amount of K2CO3 according to Scheme 3 to afford 2,3-unsaturated-α-aryl-C-glycoside 9a (Ferrier product) which was claimed to have been synthesized under acidic conditions [26] by a completely different reaction protocol. However, our spectroscopic data were not in

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

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

• dichloromethane in the presence of the sugar used in excess afforded glycoside 20 (28%) as a 1:1 mixture of α and β-anomers, accompanied by a number of by-products such as cholesteryl acetate (1a, 10%), dicholesteryl ether (18, 4%), cholest-4-en-3-one (21, 6%), and cholesta-4,6-dien-3-one (22, 9%). An analogous

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

• supply with a more challenging electrolysis reaction is a valid concern. In the following section, the use of the visible-light-driven electrolysis setup for three such reactions is illustrated. The first case stems from the use of an anodic coupling reaction to make C-glycoside derivatives from styrenes

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

• xanthohumol intake [77]. To date, xanthohumol in vivo metabolites have not been investigated regarding their anti-angiogenic activity. Genistein Genistein (60) is an isoflavone extracted from soybeans (Glycine max (L.) MERR, Fabaceae). It is present as the 7-O-glycoside genistein in the plant; however, during

Synthesis and biological evaluation of a novel MUC1 glycopeptide conjugate vaccine candidate comprising a 4’-deoxy-4’-fluoro-Thomsen–Friedenreich epitope

• Manuel Johannes,
• Maximilian Reindl,
• Bastian Gerlitzki,
• Edgar Schmitt and
• Anja Hoffmann-Röder

Beilstein J. Org. Chem. 2015, 11, 155–161, doi:10.3762/bjoc.11.15

• ’-fluoro-TF SPPS building block 11 started by conversion of peracetylated D-glucose 1 into β-thio-glycoside 2 [45][46] under Lewis acid catalysis in 81% yield (Scheme 1). Subsequent Zemplén deacetylation [47], followed by 4,6-benzylidene acetal formation and acetylation provided fully protected precursor 3

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

• 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 1 has been synthesized as its 3-aminopropyl glycoside using a combination of sequential and [3 + 2] block glycosylation strategy. A trisaccharide acceptor 11 and a disaccharide trichloroacetimidate donor 14 were synthesized from the appropriately protected monosaccharide intermediates 2 [20], 3

• glycosylation strategy has been developed to synthesize a pentasaccharide 3-aminopropyl glycoside (1) corresponding to the O-antigen of E. coli O117:K98:H4 strain. The in situ removal of the PMB ether in one-pot following the glycosylation reaction reduced the overall number of steps. Structure of the

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

• earlier attempt at the oligomerization of a 6-hydroxyglucosamine thioglycoside donor in the presence of an initiating primary alcohol resulted in a single glycosylation of the initiating alcohol to provide a glycoside product, and trace amounts of further oligomerization were detected in some cases [15

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

• linked to the backbone by a malonyl moiety were prepared via peptide coupling. The orthogonally protected glycoconjugates, bearing an acetyl-protected glycoside, were converted into their corresponding acids which are suitable building blocks for combinatorial glycopeptide synthesis. Keywords: amino

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

• performed at an early stage of the synthetic route than on valuable advanced intermediates. Accordingly, the azide reduction with NiCl2/NaBH4 protocol [29] occurred smoothly on the previously described [25] silyl glycoside 4, and after standard N-acetylation furnished acetamide 5 in high yield (Scheme 1

Indium-mediated allylation in carbohydrate synthesis: A short and efficient approach towards higher 2-acetamido-2-deoxy sugars

• Christopher Albler,
• Ralph Hollaus,
• Hanspeter Kählig and
• Walther Schmid

Beilstein J. Org. Chem. 2014, 10, 2230–2234, doi:10.3762/bjoc.10.231

• intramolecular Michael addition, leading to the formation of highly substituted tetrahydrofuran derivatives of the C-glycoside type [31]. Next, we investigated the azide reduction of compounds 6a–c under different reaction conditions. Unfortunately DTT/DIPA, thioacetic acid, tributylphosphine/H2O and H2/Pd

Expeditive synthesis of trithiotriazine-cored glycoclusters and inhibition of Pseudomonas aeruginosa biofilm formation

• Meriem Smadhi,
• Sophie de Bentzmann,
• Anne Imberty,
• Marc Gingras,
• Raoudha Abderrahim and
• Peter G. Goekjian

Beilstein J. Org. Chem. 2014, 10, 1981–1990, doi:10.3762/bjoc.10.206

• 34% yield. A second [3 + 2] cycloaddition with a different glycoside, such as D-glycopyranosyl azide 8, under the same conditions, provided for example the mixed Gal2-Glc triazine cluster 17 (Scheme 2). The efficient conjugation of unprotected glycosyl azides to trithiotriazine 2 thus provides

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

• are among the best methods to prepare C-arylglycosides, C-nucleosides and C-glycosidic oligomers when new artificial pharmacophores are approached [17]. With Suzuki cross-couplings C-glycoside analogues of phloriain with antidiabetic properties [18] or aryl-scaffolded dimers and trimers were

• compounds with β-D-talose configuration that are rarely found in nature, an exception being the antibiotic amino glycoside hygromycin B [37]. Aminopyran 17b correlates to β-D-idopyranose; iduronic acid is a component of sulfated glycosamine glycans such as chrondroitin sulfate and heparan sulfate [38]. The

• for the efficient preparation of phenyl-substituted aminopyrans and rigid divalent p-terphenyl-linked C-aryl glycoside using Suzuki cross-couplings as key method. Starting from the D-isoascorbic acid-derived diol 8, which was converted into the corresponding p-bromophenyl-substituted (Z)-nitrone, a

Concise total synthesis of two marine natural nucleosides: trachycladines A and B

• Haixin Ding,
• Wei Li,
• Zhizhong Ruan,
• Ruchun Yang,
• Zhijie Mao,
• Qiang Xiao and
• Jun Wu

Beilstein J. Org. Chem. 2014, 10, 1681–1685, doi:10.3762/bjoc.10.176

• correlations of H-1, H-3, 5-CH3 and 2-β-methyl. Then, the remaining 3-(O-2,4-dichlorobenzyl) group was removed under hydrogenation with 20% Pd(OH)2/C as a catalyst to give 12 in 91% yield. As the anomerization of the 1-O-α-methyl glycoside may occur under acidic conditions, the structural characterization may

Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: new multivalent galectin-3 ligands

• Silvia Bernardi,
• Paola Fezzardi,
• Gabriele Rispoli,
• Stefania E. Sestito,
• Francesco Peri,
• Francesco Sansone and
• Alessandro Casnati

Beilstein J. Org. Chem. 2014, 10, 1672–1680, doi:10.3762/bjoc.10.175

• . Furthermore, we confirmed that in case of this specific lectin binding the presentation of lactose units on a cone calixarene is highly preferred with respect to its isomeric form in the 1,3-alternate structure. Keywords: glycocalixarenes; cluster glycoside effect; multivalency; click chemistry; surface

• reaction between a 1-ethynyl-C-glycoside with a tetraazidocalix[4]arene (dipolarophile-on-the sugar strategy). It was suggested by the authors that the first intermolecular reaction, leading to a Cu-triazolide adduct, allows the copper ion to coordinate an ethynyl glycoside, thus entailing an

Bis(β-lactosyl)-[60]fullerene as novel class of glycolipids useful for the detection and the decontamination of biological toxins of the Ricinus communis family

• Hirofumi Dohi,
• Takeru Kanazawa,
• Akihiro Saito,
• Keita Sato,
• Hirotaka Uzawa,
• Yasuo Seto and
• Yoshihiro Nishida

Beilstein J. Org. Chem. 2014, 10, 1504–1512, doi:10.3762/bjoc.10.155

• Discussion In our preceding studies [24][25], we have shown that bis(α-mannosyl)-[60]fullerene can be obtained by a coupling reaction between 1-azidoalkyl per-O-acetyl-glycoside and C60 together with [5,6]- and [6,6]-junction isomers of mono(α-mannosyl)-[60]fullerene. The bis(glycosyl)adduct is more polar

• washed with brine, the organic layer was dried over MgSO4, filtered, and concentrated in vacuo. The residue was chromatographed on silica gel by using cyclohexane/ethyl acetate 3:2 to give glycoside 2 as a white solid (2.16 g, 48%): [α]D −11.4 (c 1.0, CHCl3); 1H NMR (500 MHz, CDCl3) δ 5.35 (dd, J3’,4

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

• independent. The isomerization of flavanonols at C-2, C-3 is not without precedent, as it was described for taxillusin – the flavanonol glycoside from Taxillus kaempferi (Japanese mistletoe) containing the 3-hydroxy-2,3-dihydro-2-phenylchromen-4-one moiety [29]. Taxillusin (24, (2R,3R)-taxifolin 3-β-D

• -glucopyranoside 6''-gallate, Figure 6) was subjected to both, basic and acidic hydrolysis during its structure elucidation. However, under these conditions four stereoisomers of the original aglycon (2R,3R)-taxifolin were formed. Base-catalyzed isomerization of another taxifolin glycoside, (2R,3R)-2,3

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

• with high selectivity. The versatility of this method has been demonstrated by applying it to differently protected glycals and by employing several nucleophiles. The obtained C-allyl glycoside has been utilized for the synthesis of a orthogonally protected 2-amino-2-deoxy-C-glycoside. Keywords: C

• -O-acetyl-D-glucal (1a) by using 3 equivalents of allyltrimethylsilane and 2 equivalents of CAN in anhydrous acetonitrile at room temperature. The reaction proceeded smoothly over 1 hour and exclusively furnished the α-C-allyl glycoside 2a in 88% yield (Table 1) [42]. We attempted the same reaction

• obtained the α-C-glycosides in an efficient manner, we explored their synthetic utility to synthesize a 2-deoxy-2-amino-α-C-glycoside. 2-Deoxy-2-amino-α-C-glycosides have received considerable attention in recent years due to their use in the synthesis of glycopeptides [50][51], glycolipids [51] and

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

• use of Et2O in the reaction solvent facilitated the formation of 1,2-cis glycoside as the major product. The concept of the Fraser–Reid’s “armed–disarmed” effect was successfully exploited in this glycosylation reaction [34][35]. Compound 5 acted as an activated or armed glycosyl donor because of the

• 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

Physalin H from Solanum nigrum as an Hh signaling inhibitor blocks GLI1–DNA-complex formation

• Midori A. Arai,
• Kyoko Uchida,
• Samir K. Sadhu,
• Firoj Ahmed and
• Masami Ishibashi

Beilstein J. Org. Chem. 2014, 10, 134–140, doi:10.3762/bjoc.10.10

• physalin F (5; IC50, 0.66 μM) [17], physalin B (6; IC50, 0.62 μM) [17], colubrinic acid (IC50, 38 μM) [18], caldenolides (IC50, 0.1–0.45 μM) [19], taepeenin D (IC50, 1.6 μM) [20] and a flavonoid glycoside (IC50, 0.5 μM) [21] were isolated by using this screening assay. Recently, we found that vitetrifolin

Stereoselectively fluorinated N-heterocycles: a brief survey

• Xiang-Guo Hu and
• Luke Hunter

Beilstein J. Org. Chem. 2013, 9, 2696–2708, doi:10.3762/bjoc.9.306

• ) is an inhibitor of the β-glucosidase from sweet almond, and it is thought to exert its inhibitory activity by mimicking the oxocarbenium intermediate of glycoside cleavage [49]. Several analogues of 31 have been investigated (41–44, Figure 11) [50][51][52], and on first inspection it is difficult to

Multigramme synthesis and asymmetric dihydroxylation of a 4-fluorobut-2E-enoate

• James A. B. Laurenson,
• John A. Parkinson,
• Jonathan M. Percy,
• Giuseppe Rinaudo and
• Ricard Roig

Beilstein J. Org. Chem. 2013, 9, 2660–2668, doi:10.3762/bjoc.9.301

• set the stage for mesylation, and conversion of 3 to fluoride 4 with an extremely economical reagent. Acetal cleavage and peracetylation released glycoside 5 which was converted to 6 via known methods. The main disadvantages of the approach are the extensive use which must be made of protection

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

• oligovalent scaffold, a number of sugar moieties, and suitable spacers which link the sugar moieties to the central core. Several examples of such molecular architectures have been obtained, and it has been demonstrated that these compounds are well-suited for the binding of lectins because of the glycoside

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

• still no universal glycosyl donor [17][18], although the first glycoside was reported by Emil Fischer more than a century ago. A series of observations in our laboratory led to the identification of a gold(III)-catalyzed glycosidation reaction that uses alkynyl glycosides as glycosyl donors [19][20][21

• ][32][33][34]. Esters at the C-2 position of the saccharide are known to impede the glycoside formation whereas ethers (–OBn) facilitate the reaction. Fraser-Reid applied the terms disarmed to deactivated glycosyl donors [e.g., esters], and armed to the activated donors [e.g., ethers] [35][36]. During

Synthesis of mucin-type O-glycan probes as aminopropyl glycosides

• David Benito-Alifonso,
• Rachel A. Jones,
• Anh-Tuan Tran,
• Hannah Woodward,
• Nichola Smith and
• M. Carmen Galan

Beilstein J. Org. Chem. 2013, 9, 1867–1872, doi:10.3762/bjoc.9.218

• access disaccharide 20b, trichloroacetimidate glycoside donor 12 was reacted with 19 in the presence of catalytic TMSOTf to yield an inseparable mixture of disaccharide product 20a and unreacted starting material. Acetal cleavage with p-TsOH in MeOH under sonication followed by acetylation of the free OH

• and higher α-selectivities than other sialosyl donors [23]. Under our reaction conditions, sialylated disaccharide 22a was prepared as a 3/1 (α/β) mixture using 1-thioadamantyl sialoside 21 as the glycoside donor upon reaction with 19, using NIS in combination with catalytic TMSOTf to activate the