Mechanochemical amorphization of chitin: impact of apparatus material on performance and contamination

• Thomas Di Nardo and
• Audrey Moores

Beilstein J. Org. Chem. 2019, 15, 1217–1225, doi:10.3762/bjoc.15.119

• expedite polysaccharide hydrolytic cleavage [20][21][22][23]. Milling can also facilitate chitin depolymerization [24] and when used with base simultaneously deacetylate and depolymerize chitin [42]. One of the key processes in the context of biomass upgrading is amorphization. Indeed, both chitin and

• of polysaccharides In a typical experiment, 200 mg of polysaccharide, chitin was placed in a jar equipped with one ball and milled in a MM 400 mixer mill for 30 min at 29.5 Hz. The resulting powder was used as is for analysis. Powder X-ray diffraction (PXRD) Sample diffractogram was recorded from 5

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

• pentasaccharide derivative using phase-transfer reaction conditions furnished the target compound in satisfactory yield. Keywords: beta-D-mannoside; biofilms; D-glucuronic acid; glycosylation; Klebsiella pneumoniae; pentasaccharide; polysaccharide; Introduction Klebsiella pneumoniae (K. pneumoniae) is a Gram

• nucleic acids and (c) loss of homogeneity of the polysaccharide fragments to name a few. It has already been established that in many cases the oligosaccharide repeating units resemble similar antigenic potential to those of the native polysaccharides [8][9][10]. Therefore, the best alternative way to get

• acid corresponding to the repeating unit of the biofilm producing polysaccharide secreted by K. pneumoniae. The unique feature of this pentasaccharide is that it contains a β-D-mannosidic moiety and a α-D-glucuronic acid moiety, which are known to be challenging from the synthetic point of view. In

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

• substitution pattern of GlcA units for the efficient synthesis of CS oligomers. Keywords: carbohydrate chemistry; chondroitin sulfate; glycosylation; oligosaccharide synthesis; stereoselectivity; Introduction Chondroitin sulfate (CS) is a highly heterogeneous polysaccharide, constituted by the repetition of

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

• the galactan chain of arabinogalactan (AG) by a unique phosphodiester linkage stemming from the 6-OH of a PG muramic acid [46]. AG is the major polysaccharide of the mycobacterial cell envelope and is composed of α-D-arabinosides and β-D-galactosides, both in the relatively uncommon furanose form [47

• -pathogenic M. smegmatis. This protein was able to agglutinate human A, B and O erythrocytes [72], and the detected hemagglutination could be inhibited by different carbohydrates. The polysaccharide arabinogalactan isolated from M. smegmatis, composed of α-D-arabinofuranosides and β-D-galactofuranosides, as

• polysaccharide mannan, composed of linear α(1→6)-linked, and α(1→2)- and α(1→3)-branched mannopyranosides, and the glycoside p-nitrophenyl α-D-mannopyranoside showed even higher hemagglutination inhibitory potency. These initial experiments let to the assumptions that mycotin is a secreted D-arabinoside- and α-D

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

• : Laboratory of Bioorganic Chemistry, NIH, NIDDK, Bethesda, MD, USA 10.3762/bjoc.14.95 Abstract Streptococcus pneumonia (SPn) is a Gram-positive bacterium which causes life threatening diseases. The bacteria protect themselves against non-specific host defence by an external polysaccharide (PS) capsule which

• most important causes of invasive pneumonococcal diseases [7]. These facts have led to extensive research towards the establishment of polysaccharide structures associated with the SPn serogroup 6 [8][9] (Figure 1). Initially, it was thought that due to their similar carbohydrate core structures the

• antibodies elicited by SPn 6A would be effective against SPn 6B as well [10][11][12][13]. But recent studies have shown that serotype specific immune responses are elicited by the antibodies and that they cross react slowly [14]. As a result the importance of the presence of the capsular polysaccharide of

Crystal structure of the inclusion complex of cholesterol in β-cyclodextrin and molecular dynamics studies

• Elias Christoforides,
• Andreas Papaioannou and
• Kostas Bethanis

Beilstein J. Org. Chem. 2018, 14, 838–848, doi:10.3762/bjoc.14.69

• drug carriers and cell cholesterol removal agents for controlling cholesterol-related disorders [3] are of special interest. β-Cyclodextrin (β-CD, Figure 1b) is a cyclic polysaccharide consisting of seven α-(1->4)-linked α-D-glucopyranose units and is well known for its ability to form inclusion

Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 416–429, doi:10.3762/bjoc.14.30

• in the presence of Et3N resulted in conversion to the glycosyl oxazoline in an excellent 95% yield. Semi-synthesis: the locust bean gum approach The naturally occurring polysaccharide locust bean gum contains a repeating Manβ(1–4)Man disaccharide unit, which is also decorated with branching α

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

• Marco Russo,
• Daniele La Corte,
• Annalisa Pisciotta,
• Serena Riela,
• Rosa Alduina and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

• AmCD–nucleic acid complexes were subjected to the heparin challenge test in order to assess their stability. Heparin is a highly negatively charged sulfated polysaccharide, which is used as a competitor polyanion. The results obtained (see Supporting Information File 1, Figure S2) show that

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• glycolipid family including LewisX pentasaccharide 117, dimeric LewisX 118 [63], tristearoyl lipomannan 119 [64], gangliosides GM1 120 [65] and GM2 121 (Figure 5) [66], microbial glycans such as the heptasaccharide repeating unit of type V group B Streptococcus capsular polysaccharide 122 [67], β-glucan

New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• in both the oxidation and alkylation reaction reveals a potential method for the valorization of lignocellulosic biomass. Keywords: alkylation; benzyl alcohol; benzyl chloride; iron oxide; mechanochemistry; microwave-assisted oxidation; polysaccharide; toluene; Introduction Heterogeneous catalysis

• on iron oxide and the polysaccharide S4, obtained from Lentinus Tigrinus (PS4). The most promising feature of such nanoentities based on iron oxide and polysaccharides is the bifunctional, oxidative [20] and acidic nature [21], which in turn can be fine-tuned to design highly active materials for

• with magnetic properties. Results and Discussion In the present study, we prepared and analyzed three different catalysts based on iron oxides and polysaccharides, in particular: iron oxide–polysaccharide 4 magnetic nanoparticles (Fe2O3-PS4-MNP), iron oxide–polysaccharide 4 (Fe2O3-PS4) and titanium

Enzymatic synthesis of glycosides: from natural O- and N-glycosides to rare C- and S-glycosides

• Jihen Ati,
• Pierre Lafite and
• Richard Daniellou

Beilstein J. Org. Chem. 2017, 13, 1857–1865, doi:10.3762/bjoc.13.180

• remains highly target-dependent and therefore a challenge in too many cases. Even so, glycochemists were very recently able to chemically synthesize the largest polysaccharide to date: a mycobacterial arabinogalactan of 92 monosaccharide units [5]. However, recent advances especially in the area of

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• similar effects as the inoculation with the living organism [29][30]. These studies also suggested that the toxin had a molecular mass of around 100,000 Da and was moderately heat stable. Four years later, in 1978, Krieg and co-workers proposed the toxin to be a phospholipoprotein–polysaccharide complex

Aqueous semisynthesis of C-glycoside glycamines from agarose

• Juliana C. Cunico Dallagnol,
• Alexandre Orsato,
• Diogo R. B. Ducatti,
• Miguel D. Noseda,
• Maria Eugênia R. Duarte and
• Alan G. Gonçalves

Beilstein J. Org. Chem. 2017, 13, 1222–1229, doi:10.3762/bjoc.13.121

• starting material to produce primary, secondary and tertiary C-glycoside glycamines, including mono- and disaccharide structures. The semisynthetic approach utilized was generally based on polysaccharide-controlled hydrolysis followed by reductive amination. All reactions were conducted in aqueous media

• -anhydro-α-L-galactopyranose unit (naturally present in the agarose structure) to all glycamines synthesized, constituting an amino-substituted C-threofuranoside moiety, which is closely related to (+)-muscarine. Keywords: amino sugar; 3,6-anhydro-α-L-galactopyranose; polysaccharide (agar); protecting

• . This moiety is indeed presumed to play an important role in the bioactivity of agar-oligosaccharides [4][5][6]. As AnGal appears polymerized within the agarose backbone, a conceivable way to obtain it as a free monosaccharide would involve the cleavage of the glycosidic linkages of the polysaccharide

Kinetic analysis of mechanoradical formation during the mechanolysis of dextran and glycogen

• Naoki Doi,
• Yasushi Sasai,
• Yukinori Yamauchi,
• Tetsuo Adachi,
• Masayuki Kuzuya and
• Shin-ichi Kondo

Beilstein J. Org. Chem. 2017, 13, 1174–1183, doi:10.3762/bjoc.13.116

• structure. Keywords: dextran; electron spin resonance (ESR); glycogen; mechanoradical; polysaccharide; Introduction There are many reports on the mechanolysis of synthetic and natural polymers. It is well-known that mechanically induced radicals, so-called mechanoradicals, are produced by the mechanolysis

• radicals. Great attention has been paid to graft polymerization of synthetic polymers onto polysaccharides, because this method easily produces a polymer combining the advantages of both natural and synthetic macromolecules [6]. A polysaccharide possessing functional group on its backbone that allows to

• initiate the polymerization is frequently used to synthesize such a graft polymer [7]. Dextran (Dx), a biodegradable polysaccharide, has been utilized as a graft copolymer backbone. The glycosidic linkages between the α-glucose units of Dx synthesized from Leuconostoc mesenteroides are composed of

Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience

• Serge Pérez and
• Daniele de Sanctis

Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114

• ]. Among the 100 crystal structures which have been solved, 30 were obtained in complex with carbohydrates, mainly pectic oligosaccharides. Polysaccharide lyases: Polysaccharide lyases (PLs) constitute a family of enzymes that cleave uronic acid-containing polysaccharide chains. The underlying mechanism is

• a β-elimination mechanism which generates an unsaturated hexenuronic acid residue and a new reducing end of the polysaccharide. At the present time, the reported number of crystal structures amounts to 190, among which 64 are complexed with carbohydrate ligands. These enzymes show a large variety of

• folds. Based on amino acid sequence similarities, polysaccharide lyases have been classified in 24 families [41]. Glycoside hydrolases: The hydrolysis of carbohydrates is the result of the action of a wide spread group of enzymes: the glycosyl hydrolases (GHs). GHs cleave the glycosidic linkage between

Correction: Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 1136–1138, doi:10.3762/bjoc.13.112

• polysaccharide-derived CDs in the presence of PEG-200 and how the starting material composition is conferred to the CD products. Corrected Scheme 22 of the original article. Hyaluronic acid (HA) and glycine-derived CDs, suspected to be decorated in unreacted HA, allowing receptor-mediated cell uptake.

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• - and disaccharides related to the capsular polysaccharide of serogroup A of Neisseria meningitides [53]. The results showed that the systems were able to activate the antigen-presenting cells, to induce the releasing of effector functions of the same cells and to stimulate T cell proliferation, but

• titers of specific IgG antibodies towards type 14 polysaccharide compared with GAuNP exclusively displaying Pn14. The GAuNP technology has also been applied in the regulation of important genes of the apoptotic pathway. New GAuNP systems displaying cMyc targeting siRNA resulted capable of inducing

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• CD and the fluorescence output was established, the smallest S-CDs gave the best fluorescence intensity of the three samples, while the largest Chi-CDs had the lowest. FTIR analysis provided evidence that the starting polysaccharide functional group composition is conferred onto the CDs. For instance

• , alginic acid has one carboxylic acid group per monomer unit, whereas chitosan is an amine-containing polysaccharide; analysis of the different CDs showed higher intensities for peaks attributed to carboxylic acid C=O bonds in both Alg-CDs and Chi-CDs. Similarly Chi-CDs showed an abundance of amine

• components in drug-delivery applications. Chitin, which is a cheap and readily available linear polysaccharide comprised of β-1,4-linked N-acetyl-D-glucosamine units, is the second most abundant biopolymer in nature and forms the backbone of crustaceans and insects exoskeleton and is also found in the cell

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• Deutschland GmbH, Magnusstrasse 11, 12489 Berlin, Germany 10.3762/bjoc.13.19 Abstract The Gram-positive bacterium Streptococcus pneumoniae causes severe disease globally. Vaccines that prevent S. pneumoniae infections induce antibodies against epitopes within the bacterial capsular polysaccharide (CPS). A

• polysaccharides (CPS) that surround them, are responsible for about 90% of infections worldwide [7]. The licensed polysaccharide vaccine Pneumovax 23 contains serotype 12F but is not efficacious in young children or elderly people, those at highest risk. The carbohydrate conjugate vaccines Prevanar13™ and

• antibodies that serve as tools for vaccine design [19] and for the detection of pathogenic bacteria such as Bacillus anthracis [20][21]. S. pneumoniae 12F CPS consists of hexasaccharide repeating units containing the [→4)-α-L-FucpNAc-(1→3)-β-D-GalpNAc-(1→4)-β-D-ManpNAcA-(1→] polysaccharide backbone with a

O-Alkylated heavy atom carbohydrate probes for protein X-ray crystallography: Studies towards the synthesis of methyl 2-O-methyl-L-selenofucopyranoside

• Roman Sommer,
• Dirk Hauck,
• Annabelle Varrot,
• Anne Imberty,
• Markus Künzler and
• Alexander Titz

Beilstein J. Org. Chem. 2016, 12, 2828–2833, doi:10.3762/bjoc.12.282

• fucosides are generally α-linked across all kingdoms of life, in glycoproteins, glycolipids, bacterial lipopolysaccharides, or low-molecular weight glycoconjugates such as glycosylated natural products. β-Linked fucosides are rarely observed, for example in the bacterial polysaccharide colanic acid [39][40

Synthesis and NMR studies of malonyl-linked glycoconjugates of N-(2-aminoethyl)glycine. Building blocks for the construction of combinatorial glycopeptide libraries

• Markus Nörrlinger,
• Sven Hafner and
• Thomas Ziegler

Beilstein J. Org. Chem. 2016, 12, 1939–1948, doi:10.3762/bjoc.12.183

• determine the coalescence temperature which resulted in calculated rotation barriers of 17.9–18.3 kcal/mol for the rotamers. Keywords: amino acids; carbohydrates; glycoconjugates; glycopeptides; N-(2-aminoethyl)glycine; Introduction The glycocalyx is a fringy or fuzzy polysaccharide layer coating most

Automated glycan assembly of a S. pneumoniae serotype 3 CPS antigen

• Markus W. Weishaupt,
• Stefan Matthies,
• Mattan Hurevich,
• Claney L. Pereira,
• Heung Sik Hahm and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2016, 12, 1440–1446, doi:10.3762/bjoc.12.139

• Berlin, Arnimallee 22, 14195 Berlin, Germany 10.3762/bjoc.12.139 Abstract Vaccines against S. pneumoniae, one of the most prevalent bacterial infections causing severe disease, rely on isolated capsular polysaccharide (CPS) that are conjugated to proteins. Such isolates contain a heterogeneous

• -preventable deaths in children under five years worldwide [5]. Over 90 different serotypes of S. pneumoniae have been identified, each of which expresses a unique capsular polysaccharide (CPS) [6][7][8][9]. The S. pneumoniae serotype 3 CPS was first isolated in 1924 [10] and its exact chemical structure was

• finally elucidated in 1941 [11], as being composed of repeating units of β-(1,3)-linked cellobiuronic acid (Figure 1). CPS plays a major role in S. pneumoniae virulence [12]. A commercial 17-valent polysaccharide vaccine was introduced in 1977, followed by a 23-valent vaccine in 1983 [13][14][15

Elucidation of a masked repeating structure of the O-specific polysaccharide of the halotolerant soil bacteria Azospirillum halopraeferens Au4

• Elena N. Sigida,
• Yuliya P. Fedonenko,
• Alexander S. Shashkov,
• Nikolay P. Arbatsky,
• Evelina L. Zdorovenko,
• Svetlana A. Konnova,
• Vladimir V. Ignatov and
• Yuriy A. Knirel

Beilstein J. Org. Chem. 2016, 12, 636–642, doi:10.3762/bjoc.12.62

• , Russia N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow 119991, Russia Chernyshevsky Saratov State University, Ulitsa Astrakhanskaya 83, Saratov 410012, Russia 10.3762/bjoc.12.62 Abstract An O-specific polysaccharide was obtained by mild acid

• hydrolysis of the lipopolysaccharide isolated by the phenol–water extraction from the halotolerant soil bacteria Azospirillum halopraeferens type strain Au4. The polysaccharide was studied by sugar and methylation analyses, selective cleavages by Smith degradation and solvolysis with trifluoroacetic acid

• , one- and two-dimensional 1H and 13C NMR spectroscopy. The following masked repeating structure of the O-specific polysaccharide was established: →3)-α-L-Rhap2Me-(1→3)-[β-D-Glcp-(1→4)]-α-D-Fucp-(1→2)-β-D-Xylp-(1→, where non-stoichiometric substituents, an O-methyl group (~45%) and a side-chain glucose

Natural products from microbes associated with insects

• Christine Beemelmanns,
• Huijuan Guo,
• Maja Rischer and
• Michael Poulsen

Beilstein J. Org. Chem. 2016, 12, 314–327, doi:10.3762/bjoc.12.34

• -rolling weevil Euops chinensis (Attelabidae) undergoes a protofarming symbiosis with the polysaccharide-degrading Penicillium herquei (family Trichocomaceae), which is planted on leave roles containing eggs and larvae to protect the offspring. P. herquei was shown to produce the antibiotic polyketide

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

• Daniel I. Hădărugă,
• Mustafa Ünlüsayin,
• Alexandra T. Gruia,
• Cristina Birău (Mitroi),
• Gerlinde Rusu and
• Nicoleta G. Hădărugă

Beilstein J. Org. Chem. 2016, 12, 179–191, doi:10.3762/bjoc.12.20

• various matrices. Matrices such as chitosan and N-lauroyl chitosan [25], N-stearoyl-O-butylglycerylchitosan [26], mixtures of soybean soluble polysaccharide and octenyl succinic anhydride [27], hydrolyzed soy protein isolate and maltodextrin [20][28], liposomes [29] and even yeast cell autolysate [30