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  Subjects -> CHEMISTRY (Total: 765 journals)
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    - CHEMISTRY (530 journals)
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CHEMISTRY (530 journals)                  1 2 3 4 5 6 | Last

2D Materials     Hybrid Journal  
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 32)
ACS Catalysis     Full-text available via subscription   (Followers: 23)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 13)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 7)
ACS Macro Letters     Full-text available via subscription   (Followers: 16)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 24)
ACS Nano     Full-text available via subscription   (Followers: 213)
ACS Photonics     Full-text available via subscription   (Followers: 2)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 8)
Acta Chemica Iasi     Open Access  
Acta Chimica Slovaca     Open Access   (Followers: 5)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access   (Followers: 1)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 2)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 4)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 8)
Advanced Functional Materials     Hybrid Journal   (Followers: 31)
Advances in Chemical Engineering and Science     Open Access   (Followers: 21)
Advances in Chemical Science     Open Access   (Followers: 8)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 13)
Advances in Drug Research     Full-text available via subscription   (Followers: 16)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 7)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 12)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 11)
Advances in Nanoparticles     Open Access   (Followers: 10)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Polymer Science     Hybrid Journal   (Followers: 38)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 9)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 4)
African Journal of Chemical Education     Open Access   (Followers: 1)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 1)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access  
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alchemy     Open Access   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 4)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Applied Sciences     Open Access   (Followers: 27)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 126)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 11)
American Journal of Chemistry     Open Access   (Followers: 17)
American Journal of Plant Physiology     Open Access   (Followers: 9)
American Mineralogist     Full-text available via subscription   (Followers: 2)
Analyst     Full-text available via subscription   (Followers: 35)
Angewandte Chemie     Hybrid Journal   (Followers: 11)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 175)
Annales UMCS, Chemia     Open Access   (Followers: 2)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 1)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 2)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 9)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 11)
Anti-Infective Agents     Hybrid Journal   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 4)
Applied Spectroscopy     Full-text available via subscription   (Followers: 12)
Applied Surface Science     Hybrid Journal   (Followers: 14)
Arabian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 4)
Autophagy     Full-text available via subscription  
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 6)
Biochemistry     Full-text available via subscription   (Followers: 163)
Biochemistry Insights     Open Access   (Followers: 4)
Biochemistry Research International     Open Access   (Followers: 4)
BioChip Journal     Hybrid Journal   (Followers: 1)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 4)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 1)
Biointerphases     Open Access  
Biomacromolecules     Full-text available via subscription   (Followers: 16)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 5)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 2)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 30)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 24)
Bioorganic Chemistry     Hybrid Journal   (Followers: 5)
Biopolymers     Hybrid Journal   (Followers: 12)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 11)
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 3)
Canadian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
Canadian Mineralogist     Full-text available via subscription   (Followers: 1)
Carbohydrate Research     Hybrid Journal   (Followers: 10)
Carbon     Hybrid Journal   (Followers: 34)
Catalysis for Sustainable Energy     Open Access   (Followers: 1)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 4)
Catalysis Science and Technology     Free   (Followers: 4)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysts     Open Access   (Followers: 6)
Cellulose     Hybrid Journal   (Followers: 4)
Central European Journal of Chemistry     Hybrid Journal   (Followers: 5)

        1 2 3 4 5 6 | Last

Journal Cover Carbohydrate Research
   [12 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0008-6215 - ISSN (Online) 0008-6215
     Published by Elsevier Homepage  [2563 journals]   [SJR: 0.675]   [H-I: 77]
  • Synthesis and X-ray studies of novel 3-C-nitromethyl-hexofuranoses
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Māris Turks , Krista Vēze , Gļebs Kiseļovs , Jevgeņija Mackeviča , Jevgeņija Lugiņina , Anatoly Mishnev , Dean Marković
      A practical method for the synthesis of three novel 3-C-nitromethyl-hexofuranoses is reported. The Henry reaction on a 1,2:5,6-di-O-isopropylidene-α-d-gulofuranose-derived ketone provided a 3-C-branched gulo-isomer as the sole reaction product. The dehydration–rehydration of the latter yielded an isopropylidene-protected 3-C-nitromethyl-galactofuranose. The reaction sequence can be also used for the synthesis of a 3-deoxy-3-C-nitromethyl-hexofuranose derivative with a gulo-configuration. Two of the newly obtained carbohydrate derivatives were characterized by X-ray crystallography.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • HClO4–silica-catalysed regioselective opening of benzylidene acetals
           and its application towards regioselective HO-4 glycosylation of
           benzylidene acetals in one-pot
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Saidulu Dara , Varma Saikam , Mahipal Yadav , Parvinder Pal Singh , Ram A. Vishwakarma
      Here we report a high-yielding method for the regioselective reductive ring opening of 4,6-O-benzylidene acetals of hexapyranosides using inexpensive and robust HClO4–SiO2 as the acidic catalyst and triethylsilane as the hydride donor. Under the optimized condition, gluco- and mannopyranosides give the respective 6-O-benzyl derivative in good to excellent yields while the corresponding galactopyranoside gives the corresponding 6-O-benzyl derivative in lower yield. As the optimized condition involves acidic catalyst, we also successfully developed further application of the present method for the tandem regioselective opening and glycosylation in one-pot.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Supramolecular self-assembled aggregates formed by pentacosa-10,12-diynyl
           amidomethyl-β-cyclodextrin
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Eunae Cho , Hwanhee Kim , Jee Eun Yang , Bong-Hyun Jun , Seung R. Paik , Seunho Jung
      Mono[6-deoxy-6-(pentacosa-10,12-diynyl amidomethyl)]-β-cyclodextrin was successfully synthesized by reacting mono-6-amino-6-deoxy-β-cyclodextrin with N-hydroxysuccinimide ester of 10,12-pentacosadiynoic acid in DMF. The modified β-cyclodextrin self-assembled and aggregated to form a worm-like supramolecular structure, and the novel supramolecular aggregates were studied using 2D nuclear magnetic resonance spectroscopy, X-ray powder diffraction, thermogravimetry, and electron microscopy. Interestingly, the synthesized pentacosa-10,12-diynyl amidomethyl-β-cyclodextrin formed columnar type self-aggregates and it was clearly differentiated from cage-like structure of native β-cyclodextrin.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Fast separation and determination of free myo-inositol by hydrophilic
           liquid chromatography
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Jiří Pazourek
      A fast liquid chromatography method for separation and determination of myo-inositol is reported. Determination of the biologically important isomer of inositols, myo-inositol, was optimized to avoid overlapping to possible interferents according to European Pharmacopoeia (glycerol, d-mannitol) and saccharose. The method in HILIC mode is extremely selective to other carbohydrates which allows to separate myo-inositol from allo- and d-chiro-inositol with resolution 12.3 and 5.2, resp. and this way it enables to separate myo-inostiol from contingent carbohydrates present in a sample matrix. Retention time of myo-inositol was 12min at 10°C, though higher temperatures (25°C or 40°C) or higher water content in the mobile phase could speed up the separation and determination to four minutes. LOD of the method was 9mg/L at 10°C, and 5mg/L at 25°C, resp.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Inhibitory effect and mode of action of chitosan solution against rice
           bacterial brown stripe pathogen Acidovorax avenae subsp. avenae RS-1
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Chunlan Yang , Bin Li , Mengyu Ge , Kaile Zhou , Yanli Wang , Ju Luo , Muhammad Ibrahim , Guanlin Xie , Guochang Sun
      Inhibitory effect and mode of action of chitosan solution against rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa) strain RS-1 was examined in this study. Result from this study indicated that chitosan solutions at 0.10, 0.20, and 0.40mg/mL inhibited the in vitro growth of Aaa strain RS-1, and in general the inhibitory efficiency increased with the increase of both chitosan concentration and the incubation time. Antibacterial activity of chitosan in this study may be mainly due to the damage of cell membrane, which was evidenced by both the cell lysis observed by transmission electron microscopy, and the increased release of cell materials based on the measurement of cell membrane integrity. Furthermore, chitosan solutions at concentrations of 0.1, 0.2, and 0.4mg/mL markedly inhibited bacterial biofilm formation compared to the control, and the inhibitory effect increased with the increase of chitosan concentration. In addition, quantitative real-time PCR of the 10 secretion system related genes revealed the differential expression of genes in particular ompA/motB, emphasizing the importance of this gene in the response of Aaa strain RS-1 to chitosan stress. These results indicated that the antibacterial mode of action of chitosan may be mainly due to membrane disruption and lysis, reduction of biofilm formation, and gene expression change. Overall, the results clearly indicated that chitosan had the potential to control bacterial brown stripe of rice.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Selective detection of epimeric pentose saccharides at physiological pH
           using a fluorescent receptor
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Matthew I. Gibson , João Neres , Elizabeth Fullam
      Epimerisation between ribofuranose and arabinofuranose sugars is crucial in several biosynthetic pathways, but is typically challenging to monitor. Here, we have screened for fluorescent boronic acids that can be used as molecular probes for the specific detection of ribofuranose over arabinofuranose sugars in solution. We show excellent specificity of the fluorescent response of 3-biphenylboronic acid to ribofuranose at physiological pH. This provides a tool for in situ monitoring of carbohydrate modifying enzymes and provides a viable alternative to traditional radiolabelled assays.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Production of rhamnolipid surfactant and its application in bioscouring of
           cotton fabric
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Zulfiqar Ali Raza , Aisha Rehman , Muhammad Tahir Hussain , Rashid Masood , Anwar ul Haq , Muhammad Tahir Saddique , Amjed Javid , Niaz Ahmad
      In the present study, a biosurfactant was synthesized by using a bacterial strain of Pseudomonas aeruginosa in minimal media provided with n-heptadecane as sole carbon source under shake-flask conditions. The biosurfactant was isolated (by acid precipitation, solvent extraction, and rotary evaporation), purified (by column chromatography and TLC), identified (by FAB-MS, FTIR, and 1D-1H NMR), and chemo-physical characterized (by tensiometry). Two principal rhamnolipid congeners were identified as dirhamnolipid RRC10C10 and monorhamnolipid RC10C10 with a CMC of 50mg/L. The biosurfactant, hence produced, was applied in sole and in combination with pectinase in scouring of cotton fabric in contrast to conventional scouring agents of NaOH and anionic surfactant SDS. The scoured cotton fabric was investigated for its weight loss, residual oil and grease, wettability, whiteness, and tensile strength. The results were compared both for conventional and biological approaches. The scouring with biosurfactant plus pectinase was equivalent to or better in efficiency than conventional alkaline scouring. The former process is additionally environmentally friendly and bio-compatible. Scanning electron microscopy of cotton fabric showed that the alkaline scouring deteriorates the fabric texture whereas bioscouring with biosurfactant plus pectinase gently removes hydrophobic impurities from the cotton fabric.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • An improved synthesis of 3,6-anhydro-d-glucal and a study of its unusual
           chemical reactivity
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Vikram Basava , Sergiu M. Gorun , Cecilia H. Marzabadi
      6-O-Tosyl-d-glucal 1 upon treatment with excess LiAlH4 unexpectedly gave 3,6-anhydro-d-glucal 2 as a major product in good yield. A crystal structure was obtained. Reaction of the anhydride 2 with N-iodosuccinimide (NIS) in excess methanol resulted in the formation of diastereomeric 2-deoxy-2-iodoglycosides. Addition of ceric (IV) ammonium nitrate and thiophenol to a solution of 2 in acetonitrile gave a mixture of 2-deoxy and 2,3-unsaturated thioglycosides. Reaction of 1,2:3,4-di-O-isopropylidine-α-d-galactopyranose with the anhydro sugar 2 in the presence of N-iodosuccinimide did not give the expected iodoglycoside mixture, but instead gave an unusual 1,4:3,6-dianhydride 7 as the major product.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • The use of O-trifluoroacetyl protection and profound influence of the
           nature of glycosyl acceptor in benzyl-free arabinofuranosylation
    • Abstract: Publication date: Available online 5 June 2014
      Source:Carbohydrate Research
      Author(s): Polina I. Abronina , Ksenia G. Fedina , Nikita M. Podvalnyy , Alexander I. Zinin , Alexander O. Chizhov , Nikolay N. Kondakov , Vladimir I. Torgov , Leonid O. Kononov
      The influence of O-trifluoroacetyl (TFA) groups at different positions of thioglycoside glycosyl donors on stereoselectivity of α-arabinofuranosylation leading to corresponding disaccharides was studied. It was shown that TFA group in thioglycoside glycosyl donors, when combined with 2-O-(triisopropylsilyl) (TIPS) non-participating group, may be regarded as an electron-withdrawing protecting group that may enhance 1,2-cis-selectivity in arabinofuranosylation, the results strongly depending on the nature of glycosyl acceptor. The reactivities of the glycosyl donors were compared with those of a similar thioglycoside with O-pentafluoropropionyl groups and the known phenyl 3,5-O-(di-tert-butylsilylene)-1-thio-α-D-arabinofuranosides with 2-O-TIPS and 2-O-benzyl groups. The “matching” in the donor–acceptor combination was found to be critical for achieving both high reactivity of glycosyl donor and β-stereoselectivity of arabinofuranosylation. The use of glycosyl donors with TFA and silyl protection may be useful in the realization of the benzyl-free approach to oligoarabinofuranosides with azido group in aglycon – convenient building blocks for the preparation of neoglycoconjugates.
      Graphical abstract image Highlights

      PubDate: 2014-06-14T15:16:04Z
       
  • Editorial board
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391




      PubDate: 2014-06-14T15:16:04Z
       
  • Graphical contents list
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391




      PubDate: 2014-06-14T15:16:04Z
       
  • Selective 4,6-O-benzylidene formation of methyl α-d-mannopyranoside
           using 2,6-dimethylbenzaldehyde
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Louis J. Liotta , Jennifer F. Chalmers , Jessica N. Falco Marshall , Timothy E. Ferreira , Hannah E. Mullen , Nicholas J. Pace
      While methyl α-d-glucopyranosides and α-d-galactopyranosides selectively form 4,6-O-benzylidenes when reacted with excess benzaldehyde in the presence of acid catalyst methyl α-d-mannopyranosides does not exhibit the same selectivity because of the cis-arrangement of the C2 and C3 hydroxyl groups. The selectivity for the 4,6-O-benzylidene is restored by using 2,6-dimethylbenzaldehyde instead of benzaldehyde. In addition the excess 2,6-dimethylbenzaldehyde is easily recovered from the reaction by extraction with petroleum ether and can be reused without further purification. The 2,6-dimethylbenzylidene exhibits properties similar to the unsubstituted benzylidene with regard to chemical synthesis.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Synthesis of Calocybe indica var. APK2 polysaccharide repeating unit
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Lei Zhang , Xiangming Zhu
      The first total synthesis of p-methoxyphenyl α-l-fucopyranosyl-(1→6)-α-d-galactopyranosyl-(1→4)-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside (2) was achieved starting from five monosaccharide building blocks. This structure represents the repeating unit of the polysaccharide isolated from edible mushroom Calocybe indica var. APK2, and was synthesized in high overall yield via a convergent ‘3+2’ glycosylation strategy.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Synthesis of α-d-glucosyl substituted methyl glycosides of
           3-deoxy-α-d-manno- and d-glycero-α-d-talo-oct-2-ulosonic acid
           (Kdo/Ko) corresponding to inner core fragments of Acinetobacter
           lipopolysaccharide
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Barbara Pokorny , Sven Müller-Loennies , Paul Kosma
      The α-d-glucopyranosyl-(1→5)-substituted methyl glycosides of 3-deoxy-α-d-manno-oct-2-ulosonic acid (Kdo), 3-deoxy-α-d-lyxo-hept-2-ulosonic acid (Kdh), and d-glycero-α-d-talo-oct-2-ulosonic acid (Ko) were prepared using orthogonally protected glycosyl acceptor derivatives via glycosylation with a torsionally disarmed 4,6-O-benzylidene protected trifluoroacetimidate glucosyl donor followed by global deprotection. The related 6-O-phosphoryl-α-d-glucopyranosyl-(1→5)-substituted Kdo and Kdh derivatives were derived from a benzylidene-protected glucosyl intermediate using phosphoramidite and phosphoryl chloride-based phosphorylation steps, respectively. The deprotected disaccharides serve as ligands to study lectin binding of Acinetobacter lipopolysaccharide core oligosaccharides.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • In a Glycosylation Reaction How Does a Hydroxylic Nucleophile Find the
           Activated Anomeric Carbon'
    • Abstract: Publication date: Available online 5 June 2014
      Source:Carbohydrate Research
      Author(s): Dennis M. Whitfield
      The mechanism by which nucleophilic hydroxyls are attracted to activated glycopyranosyl donors is not known. Besides the intrinsic attraction of oxygen centered negative dipoles towards the developing electron deficiency at the anomeric carbon only a few suggestions have been given in the literature. By studying the effect on Density Functional Theory (DFT) modeled glycosylation reactions on the presence of polar additives as tested with acetonitrile two possible effects have been identified. One was noted in a previous publication (Carbohydr. Res. 2012, 356, 180-190.) and two further examples discovered here that suggest that a lone pair of a nucleophile approaching a donor with a β-leaving group from the α-face can act as the antiperiplanar lone pair that assists leaving group departure. This interaction starts at just under a nucleophile C-1 separation of 3 Å and has an incipient bond angle of O-5-C-1-Nuc(O or N) of very close to 90° which can be associated with a bonding interaction at C-1 with the p-type orbital at C-1--O-5 of the incipient oxacarbenium ion, i.e. the LUMO of the activated donor. The 2nd interaction is less well studied and is suggested to be a similar bonding interaction which moves β-face nucleophiles to O-Nuc-C-1-Leaving groups angles close to 180°.
      Graphical abstract image Highlights

      PubDate: 2014-06-14T15:16:04Z
       
  • Fucosylation of triethyleneglycol-based acceptors into
           “clickable” α-fucosides
    • Abstract: Publication date: Available online 14 June 2014
      Source:Carbohydrate Research
      Author(s): Shuai Wang , Nicolas Galanos , Audric Rousset , Kevin Buffet , Samy Cecioni , Dominique Lafont , Stéphane P. Vincent , Sébastien Vidal
      Design of multivalent glycoconjugates can find applications such as in anti-adhesive therapy against bacterial infections. Nevertheless, the access to such macromolecules requires functionalized building blocks prepared in a minimum number of steps and on a multi-gram scale at least for the laboratory. Fucose is a representative epitope used by several bacteria for adhesion to their host cells. The stereoselective, rapid and efficient access to two “clickable” α-fucosides was re-investigated using PPh3/CBr4-promoted glycosylation of chloro- (as precursors of azido-) and alkyne-functionalized triethyleneglycols with fully unprotected L-fucose. The convenient access to such building blocks paves the way to the design of new multivalent glycoconjugates functionalized with fucose epitopes and their applications.
      Graphical abstract image Highlights

      PubDate: 2014-06-14T15:16:04Z
       
  • Gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid
           conjugate of arabinogalactan as a potential liver-targeting magnetic
           resonance imaging contrast agent
    • Abstract: Publication date: Available online 6 June 2014
      Source:Carbohydrate Research
      Author(s): Yan Xiao , Rong Xue , Tianyan You , Xiaojing Li , Fengkui Pei , Xuxia Wang , Hao Lei
      A novel biocompatible macromolecule (AG-CM-EDA-DOTA-Gd) was synthesized as a liver magnetic resonance imaging (MRI) contrast agent. AG-CM-EDA-DOTA-Gd consisted of a carboxymethyl-arabinogalactan unit conjugated with gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (Gd-DOTA) via ethylenediamine, and was specifically designed to bind to hepatocyte asialoglycoprotein in vivo, in an effort to develop a potential new tool for the diagnosis of liver diseases. The T1-relaxivity (8.78 mmol-1·L·s-1) of AG-CM-EDA-DOTA-Gd was 1.86 times than that of Gd-DOTA (4.76 mmol-1·L·s-1) in D2O at 9.4 T and 25 °C. MRI experiments showed significant enhancement in rat liver following the intravenous administration of AG-CM-EDA-DOTA-Gd (0.094 mmol Gd3+/kg body weight), which persisted for longer than Gd-DOTA (0.098 mmol Gd3+/kg body weight). The mean percentage enhancements in the liver parenchyma were 85.2±6.5% and 19.3±3.3% for AG-CM-EDA-DOTA-Gd and Gd-DOTA, respectively. The results of this study therefore indicate that AG-CM-EDA-DOTA-Gd could be used as a potential liver-targeting contrast agent for MRI.
      Graphical abstract image Highlights

      PubDate: 2014-06-14T15:16:04Z
       
  • Influence of alkyl chain length on the mesomorphism of
           5-S-alkyl-5-thiopentonolactones and 5-S-alkyl-5-thiopentitols
    • Abstract: Publication date: 17 June 2014
      Source:Carbohydrate Research, Volume 392
      Author(s): Imane Stasik , Sébastien Gottis , Céline Falentin-Daudré , Claire Meyer
      Mesomorphic properties of S-alkylthiopentonolactones (d-ribono, d-arabinono and d-xylono) and corresponding alditol derivatives with the general formula Su–SR (R=C n H2 n +1; n =5–12) are studied. It was shown that the thermotropic and lyotropic phase transition temperatures are influenced by the following structural parameters: alkyl chain length, cyclic or acyclic Su structure and alditol conformation. Besides, it seems that n parity affects thermotropic phase transition temperatures.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Structure and genetics of the O-antigen of Enterobacter cloacae C6285
           containing di-N-acetyllegionaminic acid
    • Abstract: Publication date: 17 June 2014
      Source:Carbohydrate Research, Volume 392
      Author(s): Andrei V. Filatov , Min Wang , Wenjing Wang , Andrei V. Perepelov , Alexander S. Shashkov , Lei Wang , Yuriy A. Knirel
      On mild acid degradation of the lipopolysaccharide of Enterobacter cloacae C6285, the O-polysaccharide was cleaved at residues of 5,7-diacetamido-3,5,7,9-tetradeoxy-d-glycero-d-galacto-non-2-ulosonic acid (di-N-acetyllegionaminic acid, Leg5Ac7Ac) in the main chain. The resultant oligosaccharide and an alkali-treated lipopolysaccharide were studied by sugar analysis along with 1H and 13C NMR spectroscopy, and the following structure of the tetrasaccharide repeating unit of the linear O-polysaccharide was established: →4)-α-d-Galp-(1→4)-α-Legp5Ac7Ac-(2→3)-β-d-Galp-(1→3)-β-d-GalpNAc-(1→ The O-antigen gene cluster of E. cloacae C6285 was sequenced, the gene functions were tentatively assigned by comparison with sequences in the available databases and found to be in agreement with the O-polysaccharide structure.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Enzymatic sequencing of partially acetylated chitosan oligomers
    • Abstract: Publication date: 17 June 2014
      Source:Carbohydrate Research, Volume 392
      Author(s): Stefanie Nicole Hamer , Bruno Maria Moerschbacher , Stephan Kolkenbrock
      Chitosan oligosaccharides have diverse biological activities with potentially valuable applications, for example, in the fields of medicine and agriculture. These functionalities are thought to depend on their degree of polymerization and acetylation, and possibly on specific patterns of acetylation. Chitosan oligomers with fully defined architecture are difficult to produce, and their complete analysis is demanding. Analysis is typically done using MS or NMR, requiring access to expensive infrastructure, and yielding unequivocal results only in the case of rather small oligomers. We here describe a simple and cost-efficient method for the sequencing of μg amounts of chitosan oligosaccharides which is based on the sequential action of two recombinant glycosidases, namely an exo-β-N-acetylhexosaminidase (GlcNAcase) from Bacillus subtilis 168 and an exo-β-d-glucosaminidase (GlcNase) from Thermococcus kodakarensis KOD1. Starting from the non-reducing end, GlcNAcase and GlcNase specifically remove N-acetyl glucosamine (A) and glucosamine (D) units, respectively. By the sequential addition and removal of these enzymes in an alternating way followed by analysis of the products using high-performance thin-layer chromatography, the sequence of chitosan oligosaccharides can be revealed. Importantly, both enzymes work under identical conditions so that no buffer exchange is required between steps, and the enzyme can be removed conveniently using simple ultra-filtration devices. As proof-of-principle, the method was used to sequence the product of enzymatic deacetylation of chitin pentamer using a recombinant chitin deacetylase from Vibrio cholerae which specifically removes the acetyl group from the second unit next to the non-reducing end of the substrate, yielding mono-deacetylated pentamer with the sequence ADAAA.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Graphical contents list
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393




      PubDate: 2014-06-14T15:16:04Z
       
  • Access to bifunctionalized biomolecular platforms using oxime ligation
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393
      Author(s): Karel Křenek , Radek Gažák , Gour Chand Daskhan , Julian Garcia , Michele Fiore , Pascal Dumy , Miroslav Šulc , Vladimír Křen , Olivier Renaudet
      This paper describes an efficient oxime ligation strategy to prepare multivalent conjugates wherein peptides alone or in combination with carbohydrate or oxime groups were coupled to a cyclopeptide scaffold. To demonstrate the versatility of this approach, two classes of conjugates have been prepared. In one class, we attached two or four peptide sequences to the cyclopeptide core together with free oxime groups, while the second class contains an additional substitution with four or two monosaccharides. The well-defined structure of these conjugates was confirmed by high-resolution mass spectrometry.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Editorial board
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393




      PubDate: 2014-06-14T15:16:04Z
       
  • Synthesis of the allelochemical alliarinoside present in garlic mustard
           (Alliaria petiolata), an invasive plant species in North America
    • Abstract: Publication date: 23 July 2014
      Source:Carbohydrate Research, Volume 394
      Author(s): Carl Erik Olsen , Birger Lindberg Møller , Mohammed Saddik Motawia
      The allelochemical alliarinoside present in garlic mustard (Alliaria petiolata), an invasive plant species in North America, was chemically synthesized using an efficient and practical synthetic strategy based on a simple reaction sequence. Commercially available 1,2,3,4,6-penta-O-acetyl-β-d-glucopyranose was converted into prop-2-enyl 2′,3′,4′,6′-tetra-O-acetyl-β-d-glucopyranoside and subjected to epoxidation. In a one-pot reaction, ring-opening of the epoxide using TMSCN under solvent free conditions followed by treatment of the formed trimethylsilyloxy nitrile with pyridine and phosphoryl chloride, afforded the acetylated β-unsaturated nitriles (Z)-4-(2′,3′,4′,6′-tetra-O-β-d-glucopyranosyloxy)but-2-enenitrile and its isomer (E)-4-(2′,3′,4′,6′-tetra-O-β-d-glucopyranosyloxy)but-2-enenitrile. Deacetylation of Z- and/or E-isomers afforded the target molecules alliarinoside and its isomer.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Aggregation property of glycyrrhizic acid and its interaction with
           cyclodextrins analyzed by dynamic light scattering, isothermal titration
           calorimetry, and NMR
    • Abstract: Publication date: 17 June 2014
      Source:Carbohydrate Research, Volume 392
      Author(s): Yusuke Izutani , Kenji Kanaori , Masayuki Oda
      The structural properties of glycyrrhizic acid, a sweet-tasting constituent of Glycyrrhiza glabra, and its interaction with cyclodextrins were analyzed using dynamic light scattering, isothermal titration calorimetry, and NMR. The dynamic light scattering and NMR studies showed that glycyrrhizic acid forms a water-soluble aggregate that disperses upon the addition of γ-cyclodextrin. The high sweetness of glycyrrhizic acid can be closely correlated with this aggregation, because the multimers of glycyrrhizic acid can simultaneously bind to the sweet taste receptors on the human tongue. The isothermal titration calorimetry experiments demonstrated that γ-cyclodextrin binds to glycyrrhizic acid more strongly than β-cyclodextrin, however, both reactions are accompanied by a favorable change in binding entropy. Considering the large negative change in heat capacity that is observed during the binding of γ-cyclodextrin, the main driving force for the binding is hydrophobic interactions with dehydration, which is typical for inclusion complex. NMR experiments showed that γ-cyclodextrin interacts with the central part of the aglycone moiety, not the glucuronic acid moieties, resulting in high binding affinity. It should also be noted that the two distinct complexes of glycyrrhizic acid with γ-cyclodextrin would exist in aqueous solution.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Editorial board
    • Abstract: Publication date: 17 June 2014
      Source:Carbohydrate Research, Volume 392




      PubDate: 2014-06-14T15:16:04Z
       
  • Graphical contents list
    • Abstract: Publication date: 17 June 2014
      Source:Carbohydrate Research, Volume 392




      PubDate: 2014-06-14T15:16:04Z
       
  • Efficient synthesis of 2′-deoxyzebularine and its α-anomer by
           the silyl method of N-glycosylation. Crystal structures and conformational
           study in solution
    • Abstract: Publication date: 17 June 2014
      Source:Carbohydrate Research, Volume 392
      Author(s): Katarzyna Ebenryter-Olbinska , Janina Karolak-Wojciechowska , Elzbieta Sochacka
      2′-Deoxyzebularine and its α-anomer have been efficiently synthesized with relatively high stereoselectivity by a modified procedure of the silyl method of the N-glycosidic bond formation. An SnCl4-catalyzed condensation of silylated pyrimidin-2-one with 1-α-chloro-3,5-di-O-p-toluoyl-2-deoxy-d-ribofuranose under kinetic control condition (−33°C, 1,2-dichloroethane) led to the mixture of β- and α-anomeric nucleosides in 3:1 ratio. Analogous condensation at +35°C (thermodynamic control conditions) provided mainly p-toluoyl protected α-2′-deoxyzebularine (α:β=4:1), easily separated by crystallization from the anomeric mixture. The structures of both 2′-deoxyzebularine anomers were confirmed by X-ray analysis of the crystals and conformational studies in solution performed using an NMR method.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Dense network of OH⋯O and CH⋯O interactions in the solid state
           structure of n-pentyl-2-chloro-2-deoxy-α-d-manno-sept 3-uloside
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393
      Author(s): Supriya Dey , Krishnayan Basuroy , N. Jayaraman
      Single crystal X-ray structural analysis of a septanoside, namely, n-pentyl-2-chloro-2-deoxy sept-3-uloside (1) provides many finer details of the molecular structure, in addition to its preferred twist-chair conformation, namely, 5,6 TC 3,4 conformation. Structural analysis reveals a dense network of OH⋯O, CH⋯O and van der Waals interactions that stabilize interdigitized, planar bi-layer structure of the crystal lattice.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Self-assembly behavior of tail-to-tail superstructure formed by
           mono-6-O-(4-carbamoylmethoxy-benzoyl)-β-cyclodextrin in solution and
           the solid state
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393
      Author(s): Zhe Xu , Xin Chen , Jing Liu , Dong-Qing Yan , Chun-Hua Diao , Min-Jie Guo , Zhi Fan
      A novel mono-modified β-cyclodextrin (β-CD) consisting of 4-carbamoylmethoxy-benzoyl unit at the primary side was synthesized and its self-assembly behavior was determined by X-ray crystallography and NMR spectroscopy. The crystal structure shows a ‘Yin-Yang’-like packing mode, in which the modified β-CD exhibits a channel superstructure formed by a tail-to-tail dimer as the repeating motif with the substituted group embedded within the hydrophobic cavity of the facing β-CD. The geometry of the substituted group is determined by the inclusion of the cavity and is further stabilized by two intermolecular hydrogen bonds between the carbonyl O atom and phenyl group. Furthermore, NMR ROESY investigation indicates that the self-assembly behavior of the substituted group within the β-CD cavity is retained in aqueous solution, and the effective binding constant K a was calculated to be 1330M−1 by means of 1H NMR titration according to iterative determination.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Structure and activities of a novel heteroxylan from Cassia obtusifolia
           seeds and its sulfated derivative
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393
      Author(s): Qifei Cong , Mingsheng Shang , Qun Dong , Wenfeng Liao , Fei Xiao , Kan Ding
      COB1B1S2 was isolated from an alkaline extract of Cassia obtusifolia seeds, and purified by anion-exchange and gel permeation chromatography. It contains arabinose, xylose, and glucuronic acid, in the molar ratio of 5:81:14, with an apparent molecular weight estimated to be 70.4kDa. Elucidated by using chemical and spectroscopic methods, COB1B1S2 was shown to have a backbone consisting of 1,4-linked β-d-Xylp, with one single-unit terminal α-d-GlcpA or α-l-Araf substituted at O-2 for nearly every five 1,4-linked Xylp. COB1B1S2 is structurally different from typical glucuronoxylans by its absence of methylation at O-4 of GlcA. The native COB1B1S2 showed no significant inhibition on the tube formation of human microvascular endothelial cells (HMEC) and on the growth of liver and colon cancer cells. On the contrary, COB1B1S2-Sul, prepared as the sulfated derivative of COB1B1S2, exhibited a significant inhibition on tube formation of HMEC in a dose-dependent manner, and on the growth of Bel7402 liver cancer cells. These results indicated that the introduction of sulfate groups significantly enhanced the biological activity of glucuronoxylan.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • The O-specific polysaccharide of the marine bacterium Rheinheimera
           pacifica KММ 1406T containing d- and
           l-2-acetamido-2-deoxy-galacturonic acids
    • Abstract: Publication date: 23 July 2014
      Source:Carbohydrate Research, Volume 394
      Author(s): Nadezhda A. Komandrova , Maxim S. Kokoulin , Anatoliy I. Kalinovsky , Svetlana V. Tomshich , Lyudmila A. Romanenko , Victor E. Vaskovsky
      The O-specific polysaccharide was isolated from the lipopolysaccharide of Rheinheimera pacifica KММ 1406T and studied by chemical methods along with 1H and 13C NMR spectroscopy. It was shown that the polysaccharide contains one residue each of 2-acetamido-2-deoxy-d-galactose (d-GalNAc), 2-acetamido-2-deoxy-d- and 2-acetamido-2-deoxy-l-galacturonic acids (d-GalNAcA, l-GalNAcA), 2,4-diacetamido-2,4,6-trideoxy-d-glucose (d-QuiNAc4NAc), and 4-(N-acetyl-d-alanyl)amino-4,6-dideoxy-d-glucose (d-Qui4NAlaAc) and has the following structure: →4)-α-d-GalpNAc-(1→4)-α-l-GalpNAcA-(1→3)-β-d-QuipNAc4NAc-(1→2)-β-d-Quip4NDAlaAc-(1→4)-α-d-GalpNAcA-(1→
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • New ureas containing glycosyl and diphenylphosphinyl scaffolds: synthesis
           and the first attempts to use them in asymmetric synthesis
    • Abstract: Publication date: 23 July 2014
      Source:Carbohydrate Research, Volume 394
      Author(s): Stanisław Porwański
      Chiral ureas containing glycosyl and diphenylphosphinyl scaffolds were found to be an effective organocatalyst. They were synthesised in high yields by a one-pot tandem Staudinger/aza-Wittig coupling reaction. The first attempts of using them in asymmetric synthesis are presented. Yields of the Morita–Baylis–Hillman reaction were moderate with an enantiomeric excess of up to 80%.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Structure of a sulfated xylofucan from the brown alga Punctaria
           plantaginea
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393
      Author(s): Maria I. Bilan , Alexander S. Shashkov , Anatolii I. Usov
      A polysaccharide composed of l-fucose, d-xylose, and sulfate in a molar proportion of about 5:2:3 was isolated from the brown alga Punctaria plantaginea. Polysaccharide structure was elucidated by methylation analysis, Smith degradation, as well as by 1D and 2D NMR spectroscopy. The polysaccharide was shown to contain a backbone of 3-linked α-l-fucopyranose residues, about two thirds of which are sulfated at O-2 forming trisaccharide repeating units →3)-α-l-Fucp2S-(1→3)-α-l-Fucp2S-(1→3)-α-l-Fucp-(1→. This structural regularity is masked by random distribution of non-sulfated β-d-Xylp residues attached to position 4 of the backbone. The polysaccharide is a new representative of a complex ‘fucoidan’ family of sulfated polysaccharides of brown seaweeds.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Assessing acceptor substrate promiscuity of YjiC-mediated glycosylation
           toward flavonoids
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393
      Author(s): Ramesh Prasad Pandey , Rit Bahadur Gurung , Prakash Parajuli , Niranjan Koirala , Le Thi Tuoi , Jae Kyung Sohng
      The acceptor substrate promiscuity of YjiC, a UDP-glycosyltransferase from Bacillus licheniformis, was explored with seven different classes (flavonols, flavanols, flavones, flavanones, chalcone, stilbene, and isoflavonoids) of 23 flavonoid acceptors. For most of the polyphenols used in the reactions, the enzymatic bioconversion was significantly higher with the production of multiple glucosylated derivatives. This study highlights the highly flexible non-regiospecific glycosylation ability of YjiC toward polyphenolic compounds. The catalytic potential of YjiC could be useful to generate a library of natural product glucosides.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Stereoselective C-glycosidation of d-fucose derivatives directed by the
           protective groups
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393
      Author(s): Omar Cortezano-Arellano , Camilo A. Meléndez-Becerra , Fernando Cortés , Fernando Sartillo-Piscil , Alejandro Cordero-Vargas
      Stereoselectivity in the C-glycosidation of lactones derived from d-fucose by following Kishi’s method, which involves the addition of a nucleophile onto a carbohydrate-derived lactone and subsequent reduction of the lactol, was found to be reliant on the nature of the C2 and C3 protective groups. Lactones bearing TBDMS protecting groups selectively afford 1,3-trans products (α anomer), in which the stereoselective outcome is in apparent concordance with Woerpel’s model. On the other hand, their benzylated congeners produce the 1,3-cis products (β anomer) as the major diastereoisomers. The latter results suggest an abnormal behavior during the stereoselective nucleophilic substitution at the anomeric position of the benzylated lactones.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Synthesis of chiral dopants based on carbohydrates
    • Abstract: Publication date: 1 July 2014
      Source:Carbohydrate Research, Volume 393
      Author(s): Toru Tsuruta , Tetsuo Koyama , Mikio Yasutake , Ken Hatano , Koji Matsuoka
      Chiral dopants based on carbohydrates for nematic liquid crystals were synthesized from d-glucose, and their helical twisting power (HTP) values were evaluated. The chiral dopants induced helices in the host nematic liquid crystals. An acetyl derivative having an ether-type glycosidic linkage between carbohydrate and a mesogenic moiety showed the highest HTP value of 10.4μm−1, while an acetyl derivative having an anomeric ester-type linkage did not show any HTP. It was surprising that this molecule had no HTP despite the presence of chirality in the molecule. A relationship between HTP and specific rotation was not observed in this study.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Synthesis of hyaluronic acid oligosaccharides and exploration of a
           fluorous-assisted approach
    • Abstract: Publication date: 23 July 2014
      Source:Carbohydrate Research, Volume 394
      Author(s): Giuseppe Macchione , José L. de Paz , Pedro M. Nieto
      The synthesis of hyaluronic acid oligomers (tri- and tetrasaccharide) is described. We have followed a pre-glycosylation oxidation strategy. Glucuronic acid units were directly employed in coupling reactions with suitably protected glucosamine derivatives. In order to simplify the purification of synthetic intermediates, a fluorous-assisted strategy has been also explored. Using this approach, a hyaluronic acid trisaccharide was prepared.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Synthesis of C-xylopyranosyl- and xylopyranosylidene-spiro-heterocycles as
           potential inhibitors of glycogen phosphorylase
    • Abstract: Publication date: Available online 4 June 2014
      Source:Carbohydrate Research
      Author(s): László Somsák , Éva Bokor , Beáta Czibere , Katalin Czifrák , Csenge Koppány , László Kulcsár , Sándor Kun , Enikő Szilágyi , Marietta Tóth , Tibor Docsa , Pál Gergely
      New derivatives of D-xylose with aglycons of the most efficient glucose derived inhibitors of glycogen phosphorylase were synthesized to explore the specificity of the enzyme towards the structure of the sugar part of the molecules. Thus, 2-(β-D-xylopyranosyl)benzimidazole and 3-substituted-5-(β-D-xylopyranosyl)-1,2,4-triazoles were obtained in multistep procedures from O-perbenzoylated β-D-xylopyranosyl cyanide. Cycloadditions of nitrile-oxides and O-peracetylated exo-xylal obtained from the corresponding β-D-xylopyranosyl cyanide furnished xylopyranosylidene-spiro-isoxazoline derivatives. Oxidative ring closure of O-peracetylated β-D-xylopyranosyl-thiohydroximates prepared from 1-thio-β-D-xylopyranose and nitrile-oxides gave xylopyranosylidene-spiro-oxathiazoles. The fully deprotected test compounds were assayed against rabbit muscle glycogen phosphorylase b to show moderate inhibition for 3-(2-naphthyl)-5-(β-D-xylopyranosyl)-1,2,4-triazole (IC50 = 0.9 mM) only.
      Graphical abstract image Highlights

      PubDate: 2014-06-14T15:16:04Z
       
  • Corrigendum to “Electrochemical characterization of
           globotriose-containing self-assembled monolayers on nanoporous gold and
           their binding of soybean agglutinin” [Carbohydr. Res. 373 (2013)
           9–17]
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Binod Pandey , Yih Horng Tan , Archana R. Parameswar , Papapida Pornsuriyasak , Alexei V. Demchenko , Keith J. Stine



      PubDate: 2014-06-14T15:16:04Z
       
  • A Convenient Synthesis of Novel Aza-C-disaccharide Analogues
    • Abstract: Publication date: Available online 4 June 2014
      Source:Carbohydrate Research
      Author(s): Pingzhu Zhang , Cuicui Li , Hailong Yang , Hua Wei , Zhichao Xia , Donglai Ma , Hua Chen , Kerang Wang , Xiaoliu Li
      Novel aza-C-disaccharide analogues have been conveniently synthesized by using the isoxazoline-linked C-disaccharide derivatives as the intermediates. Firstly, the C=N of isoxazoline was reduced to C-N by using DIBAL-H as reducing agent, then followed by the tandem multi-step reactions through catalytic hydrogenation with Pd(OH)2/C involving debenzylated, reductive cleavage of the N-O, condensation-cyclization of the aldehyde and the in situ generated amine group to form imine C=N and then C=N hydrogenation to form C-N, thus providing a practical and new access to the synthesis of novel aza-C-disaccharide analogues.
      Graphical abstract image Highlights

      PubDate: 2014-06-14T15:16:04Z
       
  • Structure of the capsular polysaccharide of Acinetobacter baumannii ACICU
           containing di-N-acetylpseudaminic acid
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Sof’ya N. Senchenkova , Alexander S. Shashkov , Mikhail M. Shneider , Nikolay P. Arbatsky , Anastasiya V. Popova , Konstantin A. Miroshnikov , Nikolay V. Volozhantsev , Yuriy A. Knirel
      Capsular polysaccharide was isolated by the phenol–water extraction of Acinetobacter baumannii ACICU cells and studied by sugar analysis, partial acid hydrolysis, and 1D and 2D 1H and 13C NMR spectroscopy. The polysaccharide was found to contain 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic or di-N-acetylpseudaminic acid (Pse5Ac7Ac), and the following structure of the branched tetrasaccharide repeating unit was established: The genes present in the polysaccharide gene cluster of A. baumannii ACICU are appropriate to the structure established.
      Graphical abstract image

      PubDate: 2014-06-14T15:16:04Z
       
  • Corrigendum to “Non-enveloped virus reduction with quaternized
           chitosan nanofibers containing graphene” [Carbohydr. Res. 380 (2013)
           137–142]
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Bingyu Bai , Xue Mi , Xu Xiang , Patricia A. Heiden , Caryn L. Heldt



      PubDate: 2014-06-14T15:16:04Z
       
  • Synthesis of novel 2-deoxy-β-benzyl-C-glycosides by highly stereo-
           and chemoselective hydrogenation of exo-glycals
    • Abstract: Publication date: Available online 21 April 2014
      Source:Carbohydrate Research
      Author(s): Gisela Díaz , Agustín Ponzinibbio , Rodolfo Daniel Bravo
      Novel 2-deoxy-β-benzyl-C-glycosides were prepared in good yields and excellent stereoselectivity by a route involving the Wittig reaction of glycosyl phosphonium salts and reduction of exo-glycals as key steps. Hydrogenation of benzyl protected enol ethers was performed with Pd/C(en) as effective chemoselective catalysts to afford exclusively the β anomers.
      Graphical abstract image Highlights

      PubDate: 2014-04-29T07:17:01Z
       
  • Production and identification of mannosylerythritol lipid-A homologs from
           the ustilaginomycetous yeast Pseudozyma aphidis ZJUDM34
    • Abstract: Publication date: Available online 28 April 2014
      Source:Carbohydrate Research
      Author(s): Lin-Lin Fan , Ya-Chen Dong , Yi-Fei Fan , Jun Zhang , Qi-He Chen
      Mannosylerythritol lipids (MELs) are mainly produced by strains of the genus Pseudozyma and by Ustilago maydis. These glycolipid biosurfactants exhibit not only excellent surface-active properties but also versatile bioactivities. Mannosylerythritol lipid-A (MEL-A) is worth investigating due to its self-assembling property. In this work, crude MELs were produced by resting Pseudozyma aphidis ZJUDM34 cells using different culture media. MEL-A fractions were isolated and identified using high-performance liquid chromatography combined with mass spectrometry (HPLC-MS) and gas chromatography combined with mass spectrometry (GC-MS). The results showed that MEL-A homologs had long unsaturated fatty acid chains, and the chain lengths range from C8 to C20. Nuclear magnetic resonance (NMR) was employed to confirm the chemical structures of the MEL-A homologs. Fermentation medium without NaNO3 and medium with manganese ions enhanced MEL-A production by Pseudozyma aphidis ZJUDM34.
      Graphical abstract image

      PubDate: 2014-04-29T07:17:01Z
       
  • Colourimetric and fluorometric substrates for measurement of pullulanase
           activity
    • Abstract: Publication date: Available online 28 April 2014
      Source:Carbohydrate Research
      Author(s): Barry V. McCleary , David Mangan , Vincent McKie , Claudio Cornaggia , Edward Rooney
      Specific and highly sensitive colourimetric and fluorometric substrate mixtures have been prepared for the measurement of pullulanase and limit-dextrinase activity and assays employing these substrates have been developed. These mixtures comprise thermostable α- and β-glucosidases and either 4,6-O-benzylidene-2-chloro-4-nitrophenyl-β-maltotriosyl (1-6) α-maltotrioside (BzCNPG3G3, 1; Fig. 1) as a colourimetric substrate or 4,6-O-benzylidene-4-methylumbelliferyl-β-maltotriosyl (1-6) α-maltotrioside (BzMUG3G3, 2) as a fluorometric substrate. Hydrolysis of substrates 1 and 2 by exo-acting enzymes such as amyloglucosidase, β-amylase and α-glucosidase is prevented by the presence of the 4,6-O-benzylidene group on the non-reducing end D-glucosyl residue. The substrates are not hydrolysed by any α-amylases studied, (including those from A. niger and porcine pancreas) and are resistant to hydrolysis by Pseudomonas sp. isoamylase. On hydrolysis by pullulanase (Fig. 1), the 2-chloro-4-nitrophenyl-β-maltotrioside (3) or 4-methylumbelliferyl-β-maltotrioside (4) liberated is immediately hydrolysed to D-glucose and 2-chloro-4-nitrophenol or 4-methylumbelliferone. The reaction is terminated by the addition of a weak alkaline solution leading to the formation of phenolate ions in solution whose concentration can be determined using either spectrophotometric or fluorometric analysis. The assay procedure is simple to use, specific, accurate, robust and readily adapted to automation.
      Graphical abstract image Highlights

      PubDate: 2014-04-29T07:17:01Z
       
  • Structural characterization of an acetylated glucomannan with
           antiinflammatory activity and gastroprotective property from Cyrtopodium
           andersonii
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): José P. Parente , Camila R. Adão , Bernadete P. da Silva , Luzineide W. Tinoco
      A polysaccharide with an estimated weight-average molar mass of 5.35×105 was obtained from an aqueous extract of pseudobulbs of Cyrtopodium andersonii R. Br. It was composed of d-glucose and d-mannose in 1:3 molar ratio. Chemical and spectroscopic analyses revealed a linear structure of the polymer with a backbone composed of (1→4)-linked β-d-glucopyranosyl and mannopyranosyl units slightly branched at C-2, C-3, and C-6 by side chains, as terminal non reducing residues of d-mannopyranose and d-glucopyranose. It was found to contain 14.6% of acetyl groups substituted at C-2 of (1→4)-linked β-d-mannopyranosyl units. The acetylated glucomannan demonstrated antiinflammatory and antiulcerogenic activities.
      Graphical abstract image

      PubDate: 2014-04-29T07:17:01Z
       
  • Binding assay between murine Dectin-1 and β-glucan/DNA complex with
           quartz-crystal microbalance
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Shinichi Mochizuki , Hiromi Morishita , Yoshiyuki Adachi , Yoshiki Yamaguchi , Kazuo Sakurai
      A β-glucan called schizophyllan (SPG) forms a stoichiometric complex with polynucleotides with its two main chain glucoses interacting with one nucleotide base. This complex can be used as a Dectin-1 targeting delivery for therapeutic oligonucleotides (ODN), where Dectin-1 is a membrane receptor of immunocyte cell that can recognize β-glucans. Our in vivo and in vitro assays phenomenologically implied that such a targeting is indeed achieved. However, we do not know whether SPG/ODN complexes are recognized by Dectin-1. In this study, we examined the binding affinity between SPG/poly(dA) complex and a constructed protein representing the extracellular carbohydrate-recognition domain of murine Dectin-1 by use of quartz-crystal microbalance (QCM). It was shown that the SPG/dA60 complex made form phosphodiester was recognized in the same manner as SPG, while its dissociation constant (K d) was much larger than SPG itself, that is, less affinity than SPG. When the phosphodiester linkage of dA60 was changed to phosphorothioate (denoted by dA60(S)), the QCM frequency decrease was dramatically enhanced. There seemed to be multiple binding sites; the same site as SPG and SPG/dA60, and an additional site (or sites) for which phosphate anion specific electrostatic interactions were mainly involved. Interestingly, this new site showed a comparable affinity with that between SPG and its original binding site.
      Graphical abstract image

      PubDate: 2014-04-29T07:17:01Z
       
  • Linear synthesis and conformational analysis of the pentasaccharide
           repeating unit of the cell wall O-antigen of Escherichia coli O13
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Abhishek Santra , Anshupriya Si , Rajiv Kumar Kar , Anirban Bhunia , Anup Kumar Misra
      Synthesis of the pentasaccharide repeating unit of the O-antigen of Escherichia coli O13 strain has been achieved using a straightforward linear synthetic strategy. Similar reaction conditions have been used for all glycosylations as well as protective group manipulations. All intermediate steps are high yielding and the glycosylation steps are stereoselective. The synthesized pentasaccharide was subjected to conformational analysis using 2D ROESY NMR spectral analysis and molecular dynamics (MD) simulation to get detailed information on conformation of the molecule in aqueous solution.
      Graphical abstract image

      PubDate: 2014-04-29T07:17:01Z
       
  • 6-Triazolyl-6-deoxy-β-cyclodextrin derivatives: synthesis, cellular
           toxicity, and phase-solubility study
    • Abstract: Publication date: 4 June 2014
      Source:Carbohydrate Research, Volume 391
      Author(s): Hoa Thi Le , Hyun Mi Jeon , Choon Woo Lim , Tae Woo Kim
      Heptakis{6-(4-hydroxymethyl-1H-[1,2,3]triazol-1-yl)-6-deoxy}-β-cyclodextrin (HTβCD) and heptakis{6-(4-sulfonylmethyl-1H-[1,2,3]triazol-1-yl)-6-deoxy}-β-cyclodextrin (STβCD) were prepared using copper(I)-catalyzed azide–alkyne cycloaddition between 6-azido-6-deoxy-β-CD and one of two alkynes, propargyl alcohol, and sodium propargyl sulfonate, respectively. The structures of HTβCD and STβCD were characterized by NMR techniques. NMR interpretations and computer modeling suggested that the limited freedom of rotation of the triazole moieties keeps HTβCD and STβCD rigid and compact. Water solubility tests of HTβCD and STβCD showed that the minimum water solubility of HTβCD and STβCD is at least 20times higher than that of β-CD. MTT assay showed that HTβCD and STβCD did not influence the cell viability under 1mM. A phase-solubility study of prednisolone with the CD derivatives showed increased solubility of prednisolone in the presence of increasing concentrations of HTβCD and STβCD.
      Graphical abstract image

      PubDate: 2014-04-29T07:17:01Z
       
 
 
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