Stereo- and regioselective hydroboration of 1-exo-methylene pyranoses: discovery of aryltriazolylmethyl C-galactopyranosides as selective galectin-1 inhibitors

• Alexander Dahlqvist,
• Axel Furevi,
• Niklas Warlin,
• Hakon Leffler and
• Ulf J. Nilsson

Beilstein J. Org. Chem. 2019, 15, 1046–1060, doi:10.3762/bjoc.15.102

• excellent diastereoselectivities (1:19 and 1:99 α:β ratio, respectively). Hydroboration of the glucose enol ether 6 afforded a mixture of both diastereomers (1:2.3 α:β ratio) in good yield (43% β and 18% α isolated yields, respectively). Identification of the diastereomers was accomplished by NOESY

• -interacting glucose unit in methyl β-lactoside (12) and at the same time induces a significantly better selectivity than that of methyl β-lactoside (12). Taken together, the 4-fluorophenyltriazole 1b represents the most potent mono-galactoside-derived galectin-1 inhibitor, albeit with an apparently lower

• ]. Hence, one monosaccharide moiety, glucose/N-acetylglucosamine of the common disaccharide ligands lactose/N-acetyllactosamine has effectively been replaced with an aryltriazole motif, which is chemically wholly dissimilar and more selective. This opens a route towards galectin inhibitors with improved

New terpenoids from the fermentation broth of the edible mushroom Cyclocybe aegerita

• Frank Surup,
• Florian Hennicke,
• Nadine Sella,
• Maria Stroot,
• Steffen Bernecker,
• Sebastian Pfütze,
• Marc Stadler and
• Martin Rühl

Beilstein J. Org. Chem. 2019, 15, 1000–1007, doi:10.3762/bjoc.15.98

• ) 5.00 g/L, D(+)-sucrose (Carl Roth GmbH & Co, Karlsruhe, Germany) 4.00 g/L, D-mannitol (AppliChem GmbH, ITW Company, Darmstadt, Germany) 4.00 g/L, D-glucose monohydrate (Cargill Holding Germany GmbH, Krefeld, Germany) 1.50 g/L, CaCO3 (Carl Roth GmbH & Co KG, Karlsruhe, Germany) 1.50 g/L, lactalbumin

• Drive Systems) at 23 °C. After one week of incubation the glucose concentration in the medium was tested daily. If no more free glucose could be found in the medium, the cultivation was extracted. Extraction The mycelium was separated from the fermentation broth with the help of a fluted filter. The

Towards the preparation of synthetic outer membrane vesicle models with micromolar affinity to wheat germ agglutinin using a dialkyl thioglycoside

• Dimitri Fayolle,
• Nathalie Berthet,
• Bastien Doumeche,
• Olivier Renaudet,
• Peter Strazewski and
• Michele Fiore

Beilstein J. Org. Chem. 2019, 15, 937–946, doi:10.3762/bjoc.15.90

• , DCM UMR 5250, F-38000 Grenoble, France 10.3762/bjoc.15.90 Abstract A series of alkyl thioglycosides and alkyl thiodiglycosides bearing glucose and N-acetylglucosamine residues were prepared by thiol–ene coupling in moderate to good yields (40–85%). Their binding ability towards wheat germ agglutinin

• GlcNAc monomer displays only 35 mM (Table 1). Compounds 4 and 7 bearing one and two glucose residues served as negative controls as WGA has no affinity towards glucose. This result clearly shows the high potential of the lipophilic n-alkyl thioglycoconjugates for lectine binding. In particular, compound

• to prevent the binding to primary sites. Conclusion A series of glucose and N-acetyl glucosamine-based thioglycolipids were synthesized for the first time by using thiol–ene coupling in the absence of protecting groups and in good yields. Monosaccharides where selected on the basis of similar

New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

• Iveta Chena Tichá,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2019, 15, 830–839, doi:10.3762/bjoc.15.80

• part of the spectrum consists of the CD region (5.50–3.20 ppm) with H-1 atoms of unsubstituted glucose units (4.80 ppm) and H-1I (5.03 ppm) for the substituted glucose. The signals of the H-2, H-3, H-4 and H-6 atoms of unsubstituted units are observed at around 4.00–3.00 ppm; on the other hand, the

• identified in the region around 2.00–1.20 ppm. Subsequently, 13C NMR, DEPT-edited HSQC and HMBC spectra also confirmed the substitution on the primary rim of the CD skeleton (Figure 4). The C-6 atom of the substituted glucose unit is correlated with the hydrogen signal of the triazole ring (50.41 ppm of C-6I

• alkaloid attachment to the CD skeleton through the triazole by 2D NMR measurements. This thorough investigation revealed no triple bond and a new triazole hydrogen signal while correlating carbon C6 of the substituted glucose unit with the triazole. Therefore, the prepared CD derivatives are substituted on

Synthesis of functionalized diazocines for application as building blocks in photo- and mechanoresponsive materials

• Widukind Moormann,
• Daniel Langbehn and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 727–732, doi:10.3762/bjoc.15.68

• hydrazine is quite stable towards reduction to the diamine, and can easily be reoxidized to the azo compound using CuCl2/O2. The yields are higher and more reproducible using the above reduction/reoxidation scheme. Previously applied reducing agents include Ba(OH)2/Zn [27], glucose/NaOH [20], Pb/NEt3/HCOOH

Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry

• Gábor Benkovics,
• Mihály Bálint,
• Éva Fenyvesi,
• Erzsébet Varga,
• Szabolcs Béni,
• Konstantina Yannakopoulou and
• Milo Malanga

Beilstein J. Org. Chem. 2019, 15, 710–720, doi:10.3762/bjoc.15.66

• react only with the more distant glucose units, therefore only AC and AD disubstitution takes place. The detailed study of the reaction mechanisms is out of the scope of this paper, however, the different mechanisms and reaction intermediates are likely responsible for the distinct outcome of the two

• on adjacent glucose units is not favored. The inspection of the reversed-phase HPLC chromatograms of reactions 1–3 (Figure 2) reveals that the individual diazido-β-CD regioisomers have significant retention time differences if water/acetonitrile gradient elution is applied. These differences can be

Influence of per-O-sulfation upon the conformational behaviour of common furanosides

• Alexey G. Gerbst,
• Vadim B. Krylov,
• Dmitry A. Argunov,
• Maksim I. Petruk,
• Arsenii S. Solovev,
• Andrey S. Dmitrenok and
• Nikolay E. Nifantiev

Beilstein J. Org. Chem. 2019, 15, 685–694, doi:10.3762/bjoc.15.63

• drastic changes of the ring conformation occurred while sometimes only the conformation of the exocyclic C4–C5 linkage changed. Herein we describe a combined quantum chemical and NMR conformational investigation of three common monosaccharide furanosides as their propyl glycosides: α-mannose, β-glucose

Synthesis of the aglycon of scorzodihydrostilbenes B and D

• Katja Weimann and
• Manfred Braun

Beilstein J. Org. Chem. 2019, 15, 610–616, doi:10.3762/bjoc.15.56

• -D-glucose pentaacetate in the presence of an excess of boron trifluoride etherate [20], a regioselective reaction occurred at the phenolic group in ortho-position to the alkyl side chain to give mono-glycosylated product 12. Chelation of the carbonyl and the neighboring phenolic group by the Lewis

• equipped with a stirring bar and a connection to the combined nitrogen/vacuum line. The flask was charged with dihydrostilbene 9 (330 mg, 1.04 mmol) and β-glucose pentaacetate (814 mg, 2.08 mmol) and closed with a septum. The air in the flask was replaced by nitrogen. Then, dichloromethane (4 mL) and boron

Low-budget 3D-printed equipment for continuous flow reactions

• Jochen M. Neumaier,
• Amiera Madani,
• Thomas Klein and
• Thomas Ziegler

Beilstein J. Org. Chem. 2019, 15, 558–566, doi:10.3762/bjoc.15.50

• reactions as a proof of concept for our hardware and for reactor setup. We first started with the optimization of the synthesis of the commonly used glycosyl donor acetobromo-α-D-glucose 2 under flow conditions. To the best of our knowledge, the preparation of glycosyl bromides under continuous flow

• conditions has not been published so far. For the synthesis of acetobromo glucose we used the reactor R3 (Figure 2) with a total volume of 1.5 mL. We first studied various solvents, reaction times, equivalents of HBr and temperatures for the optimization of the reaction. The best conditions are shown in

• withstood the harsh acidic conditions. Work-up of the reaction mixture and isolation of acetobromo glucose 2 was done by passing the reaction mixture through a CSTR device and two syringes for phase separation [34][35]. The procedure can easily get scaled up and provides for a convenient method for

Convergent synthesis of the pentasaccharide repeating unit of the biofilms produced by Klebsiella pneumoniae

• Arin Gucchait,
• Angana Ghosh and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2019, 15, 431–436, doi:10.3762/bjoc.15.37

• contrast to the natural version. The synthesized molecules can be linked with appropriate functionalities for their conjugation with a protein for the preparation of glycoconjugates. Recently, Cescutti et al. [11] reported the structure of a pentasaccharide composed of D-glucose, D-mannose and D-glucuronic

• addition, two α-linked D-mannose moieties and one β-linked D-glucose unit are present in the molecule. In view of the importance of oligosaccharides in the development of glycoconjugate-based therapeutics, it was decided to undertake the synthesis of a pentasaccharide corresponding to the repeating unit of

• -azidoethyl 4,6-O-benzylidene-β-D-glucopyranoside (8) [18], prepared from D-glucose, was selectively O-allylated at the 3-hydroxy group by treatment with dibutyltin oxide followed by allyl bromide in the presence of cesium fluoride [19] via the formation of a stannylene acetal to give 2-azidoethyl 3-O-allyl

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

Synthesis of nonracemic hydroxyglutamic acids

• Dorota G. Piotrowska,
• Iwona E. Głowacka,
• Andrzej E. Wróblewski and
• Liwia Lubowiecka

Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22

• boron trifluoride-catalyzed reaction with trimethylsilyl cyanide were separated chromatographically. Their transformation into (2R,3S)-2 and (2S,3S)-2, respectively, required the removal of the p-methoxybenzyl group and an acidic hydrolysis (Scheme 14) [65]. From D-glucose D-Glucose may be used as a

• chiral template for the synthesis of (2S,3R)-2 since configurations at C3 and C4 in the hexose are retained in the target compound. The disclosed strategy relied on prior transformation of D-glucose into azidofuranoside 57 [66] and next to acid 58. Homologation of acid 58 was accomplished by the Arndt

• serine or their synthetic equivalents, glutamic acid, 4-hydroxyproline and pyroglutamic acid were most frequently employed. Alternatively, α-hydroxy acids (malic, tartaric) offered the opportunity to induce chirality at Cα–N while the stereochemistry at C–OH was retained. Monosaccharides (glucose, ribose

First synthesis of cryptands with sucrose scaffold

• Patrycja Sokołowska,
• Michał Kowalski and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2019, 15, 210–217, doi:10.3762/bjoc.15.20

• sucrose scaffold (e.g., 4) can be also prepared successfully [15][16]. All macrocyclic derivatives, shown in Figure 1, were prepared from hexa-O-benzylsucrose 3 by a connection of the terminal positions of glucose (C6) and fructose (C6’) units. Results and Discussion Diol 3 may be also used as a starting

Unexpected loss of stereoselectivity in glycosylation reactions during the synthesis of chondroitin sulfate oligosaccharides

• Teresa Mena-Barragán,
• José L. de Paz and
• Pedro M. Nieto

Beilstein J. Org. Chem. 2019, 15, 137–144, doi:10.3762/bjoc.15.14

• oligosaccharides in order to improve the glycosylation efficiency [20][21]. In this approach, glucose instead of GlcA residues were employed in the oligosaccharide assembly and final oxidation and derivatization was carried out at the oligomer stage. Syndecan-1 glycopeptide containing a CS type A sequence was also

Adhesion, forces and the stability of interfaces

• Robin Guttmann,
• Johannes Hoja,
• Christoph Lechner,
• Reinhard J. Maurer and
• Alexander F. Sax

Beilstein J. Org. Chem. 2019, 15, 106–129, doi:10.3762/bjoc.15.12

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• recognition. While manno- and glucopyranosides are also present in the eukaryotic glycocalyx, galactofuranosides, arabinofuranosides, and the (1→1)-linked glucose disaccharide trehalose are unique to the mycobacterial cell wall. The occurrence of galactose in the furanose form is restricted to bacteria [56

• . identified several monosaccharides able to disperse mycobacterial clumps and inhibit bacterial cellular aggregation when added to pure cultures, including D-arabinose (both M. smegmatis and Mtb), D-xylose, inositol, and D-glucose (M. smegmatis only). The impact of D-glucose on M. smegmatis aggregation was

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• of highly performing NHC-based metathesis catalysts with N-alkyl groups, ruthenium benzylidene complexes containing carbohydrate-based NHCs derived from glucose (116) and galactose (117, Figure 21) were reported in 2009 [41]. These complexes were characterized in solution by NMR techniques which

A simple and effective preparation of quercetin pentamethyl ether from quercetin

• Jin Tatsuzaki,
• Tomohiko Ohwada,
• Yuko Otani,
• Reiko Inagi and
• Tsutomu Ishikawa

Beilstein J. Org. Chem. 2018, 14, 3112–3121, doi:10.3762/bjoc.14.291

• their broad spectrum of activities [2][3][4][5][6][7][8]. Kaempferia parviflora Wall. ex. Baker (Zingiberaceae), called “black turmeric” or “black ginger” in southern Asia, has been used as a folk medicine for vitality, as a nutritional supplement, and to reduce blood glucose levels; it has been

Repurposing the anticancer drug cisplatin with the aim of developing novel Pseudomonas aeruginosa infection control agents

• Mingjun Yuan,
• Song Lin Chua,
• Yang Liu,
• Daniela I. Drautz-Moses,
• Joey Kuok Hoong Yam,
• Thet Tun Aung,
• Roger W. Beuerman,
• May Margarette Santillan Salido,
• Stephan C. Schuster,
• Choon-Hong Tan,
• Michael Givskov,
• Liang Yang and
• Thomas E. Nielsen

Beilstein J. Org. Chem. 2018, 14, 3059–3069, doi:10.3762/bjoc.14.284

• glucose and 0.4 g/L casamino acids). For marker selection in P. aeruginosa, 30 μg mL−1 gentamycin (Gm), 50 μg mL−1 tetracycline (Tc), 100 μg mL−1 streptomycin (Strep) or 200 μg mL−1 carbenicillin (Cb) were used, as appropriate. Platinum complexes and solution preparation for MIC assay Cisplatin

Enhanced single-isomer separation and pseudoenantiomer resolution of new primary rim heterobifunctionalized α-cyclodextrin derivatives

• Iveta Tichá,
• Gábor Benkovics,
• Milo Malanga and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2018, 14, 2829–2837, doi:10.3762/bjoc.14.261

• prepare these derivatives on α-, β- or γ-CDs, disubstitutions of the α-CD primary rim occurring at two different glucose units (Figure 1) stands out for well-explored direct and indirect approaches. The indirect preparation of selectively disubstituted CDs, including protecting and deprotecting steps, was

• the third (Mes-2) to methyl groups on the mesitylene skeleton (2.60–2.30 ppm). In the CD region, three areas are well distinguished – peaks about 5.07 ppm (CD H-1) belong to H-1 protons of four unsubstituted glucose units, whereas H-1 protons of glucoses with the azido moiety and the

• mesitylenesulfonyl moieties. Both substituents on the α-CD primary rim were also confirmed by HSQC in the anomeric region distinguished in three different parts. However, the crucial splitting of six C-1 anomeric doublets for the characterization of each glucose unit was not achieved. Overall, the two different

Impact of Pseudomonas aeruginosa quorum sensing signaling molecules on adhesion and inflammatory markers in endothelial cells

• Carmen Curutiu,
• Florin Iordache,
• Veronica Lazar,
• Aurelia Magdalena Pisoschi,
• Aneta Pop,
• Mariana Carmen Chifiriuc and
• Alina Maria Hoban

Beilstein J. Org. Chem. 2018, 14, 2580–2588, doi:10.3762/bjoc.14.235

• mutant strains initially form biofilms with the same dense structure as wild strains. The mutant strains produce even "mushroom"-like structures similar to wild strains that have as carbon source, glucose, but compared to wild type, mature biofilms (10 or more days of development) produced by QS

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• and hydrogen bonding-dependent adsorption of glucose on the RGO surface results in a shift of the absorption bands coming from the C=O of RGO (from 1724 cm−1 to 1735 cm−1). Another consideration is that this process further influences the obtained material’s morphology, properties and thermal

Anomeric modification of carbohydrates using the Mitsunobu reaction

• Julia Hain,
• Patrick Rollin,
• Werner Klaffke and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1619–1636, doi:10.3762/bjoc.14.138

• native D-glucose, D-GlcNAc or D-maltose resulted in regioselective esterification of the primary OH group, leaving all other hydroxy groups including the anomeric OH unmodified [38]. On the other hand, other authors have reported that the anomeric position can be selectively modified in a Mitsunobu

• -chloroacetyl-D-glucose (30) as well as its galacto-configured analogue with the carboxylic acids 31–34 to obtain products 35–38 which are related to various pesticide agents (Scheme 6). Their results supported the theory that, along with an effect of the reaction temperature, an increase of the pKa of the

• reaction, leading to aryl glycosides with reducing sugars as the alcohol components. Grynkiewicz can be called the pioneer of Mitsunobu glycosylation, as having explored the Mitsunobu reaction for the synthesis of various aryl glycosides [24][45]. Thus, native sugars such as D-glucose and D-mannose (Scheme

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

• yields for the one-pot process are comparable or superior to those obtained with the two-step procedure (Scheme 18). Synthesis of disaccharides Classically, carbohydrates have been considered primarily an energy source for life – as in the cases of glucose, fructose and their oligosaccharides, e.g

Lanyamycin, a macrolide antibiotic from Sorangium cellulosum, strain Soce 481 (Myxobacteria)

• Lucky S. Mulwa,
• Rolf Jansen,
• Dimas F. Praditya,
• Kathrin I. Mohr,
• Patrick W. Okanya,
• Joachim Wink,
• Eike Steinmann and
• Marc Stadler

Beilstein J. Org. Chem. 2018, 14, 1554–1562, doi:10.3762/bjoc.14.132

• , strain Soce 481, was isolated in 1990 from a soil sample with plant residue collected at Alanya in Turkey in 1986 and stored at −80 °C. It was reactivated in 20 mL of liquid medium composed of 0.1% soya meal, 0.15% casitone, 0.1% yeast extracts, 0.1% CaCl2, 50 mM HEPES (11.9 g), 0.1% glucose, 0.4% starch

• % glucose, 0.8% starch, 0.1% CaCl2, 0.1% MgSO4, 11.9% yeast extract, 1 mL/L Fe-EDTA, pH 7.4. Each flask was inoculated with 100 mL of well-grown 5-day culture, and then incubated in shake flask on a rotary shaker (160 rpm) at 25 °C for 14 days as recently described in [18]. Isolation of compounds 1 and 2

• extract, 0.1% yeast extract, pH 7.0) for bacteria and MYC medium (1.0% glucose, 1.0% phytone peptones, 50 mM HEPES (11.9 g/L), pH 7.0) for fungi as previously described [20]. 150 µL of the inoculated medium was dispensed in each well in 96-well microtiter plate. 20 µL and 2 µL aliquots of 1 mg/mL of test