Synthesis of new asparagine-based glycopeptides for future scanning tunneling microscopy investigations

• Laura Sršan and
• Thomas Ziegler

Beilstein J. Org. Chem. 2020, 16, 888–894, doi:10.3762/bjoc.16.80

• Laura Srsan Thomas Ziegler Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany 10.3762/bjoc.16.80 Abstract For investigations on the biological functions of oligosaccharides and peptidomimetics, new asparagine-based mono- and disaccharides

SnCl₄-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

• Kesatebrhan Haile Asressu and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2019, 15, 2990–2999, doi:10.3762/bjoc.15.295

• -containing oligosaccharides with the desired regioselectivity is to regioselectively protect the Neu5Ac acceptor. Although Neu5Ac with a free primary OH-9 function is easy to obtain, there are only limited ways to distinguish the secondary OH-4 and OH-7 group (Figure 1). In our previous report, we easily

Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study

• Enrique A. Del Vigo,
• Carlos A. Stortz and
• Carla Marino

Beilstein J. Org. Chem. 2019, 15, 2982–2989, doi:10.3762/bjoc.15.294

• Universitaria, 1428 Buenos Aires, Argentina 10.3762/bjoc.15.294 Abstract Regioselective glycosylations allow planning simpler strategies for the synthesis of oligosaccharides, and thus reducing the need of using protecting groups. With the idea of gaining further understanding of such regioselectivity, we

• carbohydrates in living systems, oligosaccharides and other glycoconjugates are needed to carry out the corresponding glycobiological studies. The heterogeneity of carbohydrates from natural sources makes their isolation difficult, which results in synthesis being the best alternative to obtain the required

• amounts of carbohydrate-containing molecules. Due to the chemical nature of carbohydrates, with multiple possible linkage positions giving rise to different regioisomers, with two possible anomeric configurations, the chemical synthesis of complex oligosaccharides is difficult and a rather time-consuming

Automated glycan assembly of arabinomannan oligosaccharides from Mycobacterium tuberculosis

• Alonso Pardo-Vargas,
• Priya Bharate,
• Martina Delbianco and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2019, 15, 2936–2940, doi:10.3762/bjoc.15.288

• , Germany 10.3762/bjoc.15.288 Abstract Arabinomannan (AM) polysaccharides are clinical biomarkers for Mycobacterium tuberculosis (MTB) infections due to their roles in the interaction with host cells and interference with macrophage activation. Collections of defined AM oligosaccharides can help to improve

• after each glycosylation and further optimized reaction conditions allowed for the synthesis of a series of oligosaccharides, ranging from hexa- to branched dodecasaccharides. Keywords: arabinomannan; automated glycan assembly; capping; Introduction Bacterial infections caused by MTB killed 1.7

• ]. Identification of novel anti-TB agents that specifically target AMs with high sensitivity are required. Pure AM oligosaccharides may help to identify new lead compounds for the development of diagnostics. Since the isolation of pure oligosaccharides from MTB strains in sufficient quantities is challenging, the

Chemical synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide from Escherichia coli O132 in the form of its 2-aminoethyl glycoside

• Debasish Pal and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2019, 15, 2563–2568, doi:10.3762/bjoc.15.249

• chemically synthesized oligosaccharides before [8][9][10]. The corresponding aminopropyl linker has also been used by others [11]. The chemically synthesized oligosaccharide structure will help to elucidate further biological implications of the O-antigen concerned and possible vaccine potential. Results and

Robust perfluorophenylboronic acid-catalyzed stereoselective synthesis of 2,3-unsaturated O-, C-, N- and S-linked glycosides

• Madhu Babu Tatina,
• Xia Mengxin,
• Rao Peilin and
• Zaher M. A. Judeh

Beilstein J. Org. Chem. 2019, 15, 1275–1280, doi:10.3762/bjoc.15.125

• molecular recognition, cell–cell interaction, immunological recognition and transmission of biological information [4][5][6]. They are easily transformed into important bioactive compounds such as oligosaccharides, glycopeptides, nucleosides, antibiotics, uronic acids and other natural products [1][2][3

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• the natural cationic peptide antibiotics [60] or as a way to constrain peptide sequences in protein epitope conformations [61]. In this regard, the groups of Rivera and Wessjohann have pioneered the utilization of MCRs for the conjugation of oligosaccharides [62] and peptides [63][64] to steroids

Molecular recognition using tetralactam macrocycles with parallel aromatic sidewalls

• Dong-Hao Li and
• Bradley D. Smith

Beilstein J. Org. Chem. 2019, 15, 1086–1095, doi:10.3762/bjoc.15.105

• (i.e., 27+·Cl−). Not only was 27+·Cl− a high affinity guest for tetralactam B, it was also an effective template for the macrocyclization reaction that produced tetralactam B. 3.5. Oligosaccharides The advantages of the amphiphilic cavity are also highlighted by the work of the Davis group who have

• interactions and higher monosaccharide affinities. In addition, there was a remarkable improvement in affinity for larger oligosaccharides, presumably due to a stronger hydrophobic effect elicited by the extended hydrophobic surface of the tetralactam sidewalls. The Davis work has also uncovered a binding

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

• ; cinchona alkaloids; CuAAC click reaction; cyclodextrin; organocatalysts; Introduction Cyclodextrins (CDs) [1], cyclic oligosaccharides consisting of α-D-glucopyranoside units, and their derivatives are widely used in many industrial and research areas for their ability to form supramolecular inclusion

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

• selective functionalization of these cyclic oligosaccharides can remarkably improve their complexing ability and enables their application as artificial enzymes [2][3][4], chiral resolving agents [5], stimuli-responsive materials [6], molecular sensors [7] or bioactive hosts with significant emerging

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

• torsion angles [10]. The knowledge of conformational changes occurring in sulfated furanosides may be important for better understanding of the driving force of the pyranoside-into-furanoside rearrangement [14][15][16], which is widely used for preparative synthesis of different oligosaccharides

Design and synthesis of multivalent α-1,2-trimannose-linked bioerodible microparticles for applications in immune response studies of Leishmania major infection

• Chelsea L. Rintelmann,
• Tara Grinnage-Pulley,
• Kathleen Ross,
• Daniel E. K. Kabotso,
• Angela Toepp,
• Anne Cowell,
• Christine Petersen,
• Balaji Narasimhan and
• Nicola Pohl

Beilstein J. Org. Chem. 2019, 15, 623–632, doi:10.3762/bjoc.15.58

• found to be safe after administration into the footpad of mice and demonstrated a similar response to α-1,2-trimannose-coated latex beads during L. major footpad infection. Furthermore, the bioerodible microparticles allowed for investigation of the role of pathogen-associated oligosaccharides for

• , synthetic pathogen-associated carbohydrate probes are necessary to understand the LPG structure-to-function relationship. These synthetic oligosaccharides also provide a structurally homogeneous standard to study how these glycans interact with the host immune system in an effort to develop effective anti

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

• shows a good resistance towards common solvents. A disadvantage of FDM is the relatively low resolution [20]. Oligosaccharides, especially as glycoconjugates, play a crucial biological role in nature, e.g., for signal transduction in cell–cell recognition, infection processes, and immunology [21][22

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

• the oligosaccharide fragments corresponding to the capsular polysaccharides or polysaccharides secreted by the bacterial strains, is to develop effective synthetic strategies. The structure and glycosyl linkages of the monosaccharide units remain conserved in the synthesized oligosaccharides in

• 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

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

• ring, functional groups etc. Carbohydrates are especially useful platforms for macrocycles being able to recognize enantiomers. Special attention is directed to native and modified cyclodextrins, cyclic oligosaccharides, which have found wide application in many aspects of chemistry and industry [3][4

• structure. Up to date, only monosaccharides have been intensively used as chiral building blocks in the synthesis of such macrocycles. Less attention, however, has been paid to macrocycles with disaccharides (or oligosaccharides) being a part of the ring [6][7][8]. We have proposed to use sucrose (1) as a

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

• -assisted synthesis of chondroitin sulfate (CS) oligosaccharides. Following this approach, a CS tetrasaccharide was prepared. However, in contrast to our previous results, a significant loss of β-selectivity was observed in [2 + 2] glycosylations involving N-trifluoroacetyl-protected D-galactosamine donors

• D-glucuronic acid (GlcA)-β(1→3)-N-acetyl-D-galactosamine (GalNAc)-β(1→4) disaccharides that may contain sulfate groups at different positions. This biopolymer plays a key role in biological events such as brain development and cancer [1]. The preparation of well-defined CS oligosaccharides is

• 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

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

• modifications of glycocalyx proteins are N-glycans (asparagine-linked) and O-glycans (serine- or threonine-linked), while glycosphingolipids are the major subclass of glycosylated lipids in the cell membrane of human cells (Figure 2). While many core elements of glycocalyx oligosaccharides are conserved between

• -GalNAc), and sialic acid residues, such as N-acetyl-D-neuraminic acid (Neu5Ac). While most of the internal glycosides in eukaryotic oligosaccharides are β-linked, terminally localized carbohydrates are often attached via an α-glycosidic bond. (R = H or glycosidic linkage; the figure of the Mtb cell wall

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

• ; heterobifunctionalized alpha-cyclodextrin; homobifunctionalized alpha-cyclodextrin; regioisomers; regioselectivity; Introduction Cyclodextrins, cyclic cone-shaped oligosaccharides [1], have long attracted interest for their properties in host–guest complexes both in research and in pharmaceutical and food industry

Synthesis of α-D-GalpN₃-(1-3)-D-GalpN₃: α- and 3-O-selectivity using 3,4-diol acceptors

• Emil Glibstrup and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2018, 14, 2805–2811, doi:10.3762/bjoc.14.258

• ] has triggered the interest of carbohydrate chemists since the early days of complex oligosaccharides synthesis. The structure of the pentasaccharide part of the Forssman antigen was resolved in the seventies [3][4] and soon thereafter Paulsen and Bünsch finished the chemical synthesis of the

Nucleoside macrocycles formed by intramolecular click reaction: efficient cyclization of pyrimidine nucleosides decorated with 5'-azido residues and 5-octadiynyl side chains

• Jiang Liu,
• Peter Leonard,
• Sebastian L. Müller,
• Constantin Daniliuc and
• Frank Seela

Beilstein J. Org. Chem. 2018, 14, 2404–2410, doi:10.3762/bjoc.14.217

• analysis of the cyclic ketones muscone and civetone [1]. Other classical examples are cyclic peptides such as valinomycin and cyclic oligosaccharides like cyclodextrins [2][3][4]. The literature has been recently reviewed [5]. Also, oligonucleotides form cyclic structures commonly existing in plasmid DNA

Synthesis of 1,4-imino-L-lyxitols modified at C-5 and their evaluation as inhibitors of GH38 α-mannosidases

• Maroš Bella,
• Sergej Šesták,
• Ján Moncoľ,
• Miroslav Koóš and
• Monika Poláková

Beilstein J. Org. Chem. 2018, 14, 2156–2162, doi:10.3762/bjoc.14.189

• ], disaccharides or higher oligosaccharides [5][6] as well as multivalent [7][8] carbohydrate units have been developed. These glycomimetics and glycopeptides have also found applications as bioactive compounds [9][10]. One group of the scaffolds includes iminosugars [11][12] as analogues of the monosaccharides

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

• linkages in calicheamycin oligosaccharides [112][113]. This option was applied in the synthesis of trichostatin D involving glucose derivative 2 and N-hydroxyhexahydrophthalimide as the glycosyl acceptor to give 125 (Scheme 26) [114]. By using diverse N-hydroxylated azaheterocycles in the Mitsunobu

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

• ; nucleoside; oligosaccharide; Introduction Nucleic acids and oligosaccharides are both mandatory polymers for the maintenance of life and cell growth. The former exists in nuclei and codes genetic information, which is transformed into proteins through a transcription process known as the “central dogma

• quite important, and informs the development of new drugs for diseases including cancers and infectious diseases caused by viruses [4][5][6][7]. Indeed, many drugs related to nucleic acids and oligosaccharides have been developed and used in clinical fields. Synthetic chemists have contributed to the

• 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

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

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

• induced upon binding [21]. More recently, a second binding site has been discovered on the edge of the B-subunit sitting closer to the A-subunit face (Figure 2) [13][22][23][24][25], This secondary binding site recognises fucosylated structures including blood group oligosaccharides of the Lewis-y family