- Synthesis of modified D-mannose core derivatives and their impact on GH38 α-mannosidases
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Nine new compounds having five- and modified six-member carbohydrate core derived from D-lyxose or D-mannose, and non-hydrolysable aglycones (benzylsulfonyl or aryl(alkyl)triazolyl) were synthesised to investigate their ability to inhibit the recombinant
- Poláková, Monika,Horák, Radim,?esták, Sergej,Holková, Ivana
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Read Online
- Calcium hypophosphite mediated deiodination in water: Mechanistic insights and applications in large scale syntheses of d-quinovose and d-rhamnose
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The inorganic calcium hypophosphite was found to be a cheap, non-toxic, water-soluble and environmentally friendly reducing reagent for radical deiodination in water. Thorough mechanism studies revealed that calcium hypophosphite was oxidized to water insoluble calcium phosphite which was the major co-product of the deiodination reaction. Based on this observation, a practical synthesis of rare d-quinovose and d-rhamnose from cheap and commercially available materials on a hundred-mmol scale was reported.
- Song, Zejin,Meng, Lingkui,Xiao, Ying,Zhao, Xiang,Fang, Jing,Zeng, Jing,Wan, Qian
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Read Online
- The structure of the O-specific polysaccharide from Ralstonia pickettii
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The following structure of the Ralstonia pickettii have been determined using NMR and chemical methods:→4)-α-D-Rha-(1→4)-α-L- GalNAcA-(1→3)-β-D-BacNAc-(1→
- Vinogradov, Evgeny,Nossova, Ludmila,Swierzko, Anna,Cedzynski, Maciej
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Read Online
- Total Synthesis of Tiacumicin A. Total Synthesis, Relay Synthesis, and Degradation Studies of Fidaxomicin (Tiacumicin B, Lipiarmycin A3)
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The commercial macrolide antibiotic fidaxomicin was synthesized in a highly convergent manner. Salient features of this synthesis include a β-selective noviosylation, a β-selective rhamnosylation, a ring-closing metathesis, a Suzuki coupling, and a vinylo
- Hattori, Hiromu,Kaufmann, Elias,Miyatake-Ondozabal, Hideki,Berg, Regina,Gademann, Karl
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Read Online
- Modular Total Synthesis and Cell-Based Anticancer Activity Evaluation of Ouabagenin and Other Cardiotonic Steroids with Varying Degrees of Oxygenation
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A Cu(II)-catalyzed diastereoselective Michael/aldol cascade approach is used to accomplish concise total syntheses of cardiotonic steroids with varying degrees of oxygenation including cardenolides ouabagenin, sarmentologenin, 19-hydroxysarmentogenin, and 5-epi-panogenin. These syntheses enabled the subsequent structure activity relationship (SAR) studies on 37 synthetic and natural steroids to elucidate the effect of oxygenation, stereochemistry, C3-glycosylation, and C17-heterocyclic ring. Based on this parallel evaluation of synthetic and natural steroids and their derivatives, glycosylated steroids cannogenol-l-α-rhamnoside (79a), strophanthidol-l-α-rhamnoside (92), and digitoxigenin-l-α-rhamnoside (97) were identified as the most potent steroids demonstrating broad anticancer activity at 10-100 nM concentrations and selectivity (nontoxic at 3 μM against NIH-3T3, MEF, and developing fish embryos). Further analyses indicate that these molecules show a general mode of anticancer activity involving DNA-damage upregulation that subsequently induces apoptosis.
- Khatri, Hem Raj,Bhattarai, Bijay,Kaplan, Will,Li, Zhongzheng,Curtis Long, Marcus John,Aye, Yimon,Nagorny, Pavel
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supporting information
p. 4849 - 4860
(2019/03/26)
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- Synthesis of Deoxyglycosides by Desulfurization under UV Light
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This study was performed to develop a highly efficient method whereby desulfurization could be completed in 0.5 h under ultraviolet light, at room temperature, and in the presence of trialkylphosphine. Using this method, deoxyglycosides could be produced from sulfur-containing glycosides in almost quantitative yields. The much higher reactivity of desulfurization with triethylphosphine versus that with triethylphosphite is also discussed.
- Ge, Jian-Tao,Li, Ying-Ying,Tian, Jun,Liao, Rong-Zhen,Dong, Hai
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p. 7008 - 7014
(2017/07/15)
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- Synthesis of β-(1→2)-Linked 6-Deoxy- l -altropyranose Oligosaccharides via Gold(I)-Catalyzed Glycosylation of an ortho-Hexynylbenzoate Donor
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The β-(1→2)-linked 6-deoxy-l-altropyranose di- to pentasaccharides 2-5, relevant to the O-antigen of the infectious Yersinia enterocolitica O:3, were synthesized for the first time. The challenging 1,2-cis-altropyranosyl linkage was assembled effectively via glycosylation with 2-O-benzyl-3,4-di-O-benzoyl-6-deoxy-l-altropyranosyl ortho-hexynylbenzoate (7) under the catalysis of PPh3AuNTf2. NMR and molecular modeling studies showed that the pentasaccharide (5) adopted a left-handed helical conformation.
- Shen, Zhengnan,Mobarak, Hani,Li, Wei,Widmalm, G?ran,Yu, Biao
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p. 3062 - 3071
(2017/03/23)
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- Direct glycosylation of unprotected and unactivated sugars using bismuth nitrate pentahydrate
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Bi(NO3)3, a low-cost, mild, and environmentally green catalyst, has been successfully utilized for Fischer glycosylation for the synthesis of alkyl/aryl glycopyranosides by reacting unprotected sugars, namely, D-glucose, L-rhamnose, D-galactose, D-arabinose, and N-acetyl-D-glucosamine with various alcohols in good to excellent yields. The glycosides were formed with high α-selectivity. Further, an expedient separation of α- and β-glycosides using silver nitrate-impregnated silica gel flash liquid chromatography has been developed.
- Polanki, Innaiah K.,Kurma, Siva H.,Bhattacharya, Asish K.
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p. 196 - 205
(2015/06/08)
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- Total Synthesis of the Glycosylated Macrolide Antibiotic Fidaxomicin
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The first enantioselective total synthesis of fidaxomicin, also known as tiacumicin B or lipiarmycin A3, is reported. This novel glycosylated macrolide antibiotic is used in the clinic for the treatment of Clostridium difficile infections. Key features of
- Kaufmann, Elias,Hattori, Hiromu,Miyatake-Ondozabal, Hideki,Gademann, Karl
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supporting information
p. 3514 - 3517
(2015/07/28)
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- Catalytic and regioselective oxidation of carbohydrates to synthesize keto-sugars under mild conditions
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A new catalytic and regioselective approach for the synthesis of keto-sugars is described. An organotin catalyst, Oc2SnCl2, in the presence of trimethylphenylammonium tribromide ([TMPhA]+Br3-) accelerates the regioselective oxidation at the axial -OH group of 1,2-diol moieties in galactopyranosides. The reaction conditions can also be used for the regioselective oxidation of various carbohydrates.
- Muramatsu, Wataru
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p. 4846 - 4849
(2015/04/27)
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- Mannose-binding geometry of pradimicin A
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Pradimicins (PRMs) and benanomicins are the only family of non-peptidic natural products with lectin-like properties, that is, they recognize D-mannopyranoside (Man) in the presence of Ca2+ ions. Coupled with their unique Man binding ability, t
- Nakagawa, Yu,Doi, Takashi,Taketani, Takara,Takegoshi,Igarashi, Yasuhiro,Ito, Yukishige
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supporting information
p. 10516 - 10525
(2013/08/23)
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- Characterization of ulvan extracts to assess the effect of different steps in the extraction procedure
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An effective application development of the polysaccharide ulvan requires a comprehensive knowledge about the influence of the extraction process on composition of the extracts and in ulvan itself. In this context, the two main objectives of the present work are (1) the establishment of an efficient extraction process for ulvan and (2) development of an accurate characterization methodology to evaluate the extract composition and ulvan content. Three ulvan-rich extracts obtained by different schemes of extraction were studied. The methodology for the analysis was improved and a detailed analysis of extracted ulvan was provided. The polysaccharide is rich in ulvanobiuronic acid 3-sulfate type A [→4)-β-d-GlcAp-(1 → 4)-α-l-Rhap 3S-(1→], with minor amounts of ulvanobiuronic acid 3-sulfate type B [→4)-α-l-IdoAp-(1 → 4)-α-l-Rhap 3S-(1→]. The extract with the higher degree of purification is a high molecular weight polysaccharide (790 kDa) composed of rhamnose (22.4%), glucuronic acid (22.5%), xylose (3.7%), iduronic acid (3.1%) and glucose (1.0%). It is highly sulfated (32.2%) and contains 1.3% of proteins and 10.3% of inorganic material. Applying simple extraction scheme it was possible to obtain an extract from green algae with high content of ulvan without affecting the overall chemical structure of the polysaccharide.
- Costa, Carina,Alves, Anabela,Pinto, Paula R.,Sousa, Rui A.,Borges Da Silva, Eduardo A.,Reis, Rui L.,Rodrigues, Alírio E.
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experimental part
p. 537 - 546
(2012/06/15)
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- Steroidal saponins from the roots of Smilax sp.: Structure and bioactivity
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Phytochemical characterization of a commercial herb sample supplied as Smilax ornata Lem. (sarsaparilla) led to the isolation of five steroidal saponins, including two new furostanol saponins sarsaparilloside B (1) and sarsaparilloside C (2), whose structures were elucidated via a combination of multistage mass spectrometry (MSn), 1D and 2D NMR experiments, and chemical degradation. The previously unreported spectroscopic characterization of sarsaparilloside (3), Δ20(22)-sarsaparilloside (4), and parillin (5) is also provided. The antiproliferative activity of the isolated saponins was compared in six human cell lines derived from different tumor types and one of the structures (2) was particularly active against the HT29 colon tumor cell line.
- Challinor, Victoria L.,Parsons, Peter G.,Chap, Sonet,White, Eve F.,Blanchfield, Joanne T.,Lehmann, Reginald P.,De Voss, James J.
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experimental part
p. 504 - 511
(2012/05/19)
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- Organotin-catalyzed highly regioselective thiocarbonylation of nonprotected carbohydrates and synthesis of deoxy carbohydrates in a minimum number of steps
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Nonprotected carbohydrates: The catalytic regioselective thiocarbonylation of carbohydrates by using organotin dichloride under mild conditions was demonstrated. The reaction afforded various deoxy saccharides in high yields and excellent regioselectivity in a minimum number of steps. The regioselectivity of the thiocarbonylation is attributed to the intrinsic character of the carbohydrates based on the stereorelationship of their hydroxy groups (see scheme). Copyright
- Muramatsu, Wataru,Tanigawa, Satoko,Takemoto, Yuki,Yoshimatsu, Hirofumi,Onomura, Osamu
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supporting information; experimental part
p. 4850 - 4853
(2012/05/20)
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- Access to antigens related to anthrose using pivotal cyclic sulfite/sulfate intermediates
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Anthrose is the upstream terminal unit of the tetrasaccharide side chain from a major glycoprotein of Bacillus anthracis exosporium and is part of important antigenic determinants. A novel entry to anthrose-containing antigens and precursors is described. The synthetic route, starting from d(+)-fucose, makes use of intermediates featuring a cyclic sulfite or sulfate function which serves successively as a protecting and a leaving group.
- Milhomme, Ophelie,John, Cedric,Djedaini-Pilard, Florence,Grandjean, Cyrille
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scheme or table
p. 5985 - 5998
(2011/09/16)
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- PROCESS FOR THE SYNTHESIS OF L-FUCOSYL DL- OR OLIGOSACCHARIDES AND NOVEL 2,3,4 TRIBENZYL-FUCOSYL DERIVATIVES INTERMEDIATES THEREOF
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The present invention relates to a process for the synthesis of L-fυcosyl di- or oligosaccharides and their novel 2,3,4-tri-O-benzyl-fucosyl synthetic intermediates derivatives of easy crystallization. In particular the present invention relates to a process applicable to industrial scale for the synthesis of 2'O-fucosyl lactose.
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Page/Page column 9; 20-21
(2010/08/05)
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- β-D-Galactosidase from Paenibacillus thiaminolyticus catalyzing transfucosylation reactions
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A genomic library of bacterial strain Paenibacillus thiaminolyticus was constructed and the plasmid DNA of the clone, containing the gene encoding β-D-galactosidase with β-D-fucosidase activity, detected by 5-bromo-4-chloro-3-indoxyl β-D-galactopyranoside, was sequenced. Cells of Escherichia coli BL21 (DE3) were used for production of the enzyme in the form of a histidine-tagged protein. This recombinant fusion protein was purified using Ni-NTA agarose affinity chromatography and characterized by using p-nitrophenyl β-D-fucopyranoside (Km value of 1.18 ± 0.06 mmol/L), p-nitrophenyl β-D-galactopyranoside (Km value of 250 ± 40 mmol/L), p-nitrophenyl β-D-glucopyranoside (Km value of 77 ± 6 mmol/L), and lactose (Km value of 206 ± 5 mmol/L) as substrates. Optimal pH and temperature were estimated as 5.5 and 65°C, respectively. According to the amino acid sequence, the molecular weight of the fusion protein was calculated to be 68.6 kDa and gel filtration chromatography confirmed the presence of the enzyme in a monomeric form. In the following step, its ability to catalyze transfucosylation reactions was tested. The enzyme was able to catalyze the transfer of fucosyl moiety to different p-nitrophenyl glycopyranosides (producing p-nitrophenyl β-D-fucopyranosyl-(1,3)-β-D-fucopyranoside, p-nitrophenyl β-D-fucopyranosyl-(1,3)-α-D-glucopyranoside, p-nitrophenyl β-D-fucopyranosyl-(1,3)-α-D-mannopyranoside, and p-nitrophenyl β-D-fucopyranosyl-(1,6)-α-D-galactopyranoside) and alcohols (producing methyl β-D-fucopyranoside, ethyl β-D-fucopyranoside, 1-propyl β-D-fucopyranoside, 2-propyl β-D-fucopyranoside, 1-octyl β-D-fucopyranoside, and 2-octyl β-D-fucopyranoside). These results indicate the possibility of utilizing this enzyme as a promising tool for enzymatic synthesis of β-D-fucosylated molecules. The Author 2009. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oxfordjournals.org.
- Benesova, Eva,Lipovova, Petra,Dvorakova, Hana,Kralova, Blanka
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experimental part
p. 442 - 451
(2011/02/24)
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- Phorbasides A-E, cytotoxic chlorocyclopropane macrolide glycosides from the marine sponge Phorbas sp. CD determination of C-methyl sugar configurations
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(Chemical Equation Presented) Five new cytotoxic macrolide glycosides phorbasides A-E (3-7), each possessing a macrolide ring appended to a rare ene-yne-trans-2-chlorocyclopropane, were isolated from the same Western Australian sponge (Phorbas sp.) that provided phorboxazoles A and B. The structures of 3-7 were solved by analysis of spectroscopic data including NMR, MS, and CD. A synthesis of methyl 2-O-methyl-α-L-evalose from L-rhamnose was completed and used for configurational assignment of the sugar residue in 3. Acid-catalyzed methanolysis of 3 followed by two-step derivatization of the liberated O-methyl glycoside gave a vicinal 4-O-naphthoyl/tertiary 3-N-(2-aminonaphthyl)carbamate derivative that exhibited exciton coupled CD identical with that of the derivative prepared from synthetic 1,2-O-dimethyl-α-L-evalose.
- MacMillan, John B.,Guang, Xiong-Zhou,Skepper, Colin K.,Molinski, Tadeusz F.
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p. 3699 - 3706
(2008/09/20)
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- Structure of the repeat unit of the Alteromonas addita type strain KMM 3600T O-specific polysaccharide
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The O-specific polysaccharide of Alteromonas addita type strain KMM 3600T is constructed of trisaccharide repeat units containing L-rhamnose, D-glucose, and D-galactose. It was established that the O-specific polysaccharide consists of trisaccharide repeat units with the structure →3)-α-D-Galp- (1→3)-α-L-Rhap-(1→3)-α-D-Glcp-(1→ based on monosaccharide analysis, Smith degradation, PMR and 13C NMR spectroscopy, and two-dimensional COSY, HSQC, and HMBC. Springer Science+Business Media, Inc. 2008.
- Gorshkova,Isakov,Denisenko,Nazarenko,Ivanova,Shevchenko
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experimental part
p. 549 - 551
(2009/04/06)
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- A convenient synthesis of furanose-free D-fucose per-O-acetates and a precursor for anthrose
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Methyl 3,4-O-isopropylidene-α- or β-D-galactopyranoside was iodinated with triiodoimidazole in the presence of triphenylphosphane and the corresponding 6-deoxy-6-iodo derivatives 5 or 6, respectively, were converted to furanose-free 1,2,3,4-tetra-O-acetyl-α,β-D-fucopyranose. A key intermediate for chemical synthesis of anthrose, a constituent of the tetrasaccharide of major glycoprotein of Bacillus anthracis exosporium, 1-O-acetyl-4-azido-2-O-benzoyl-3-O-benzyl-4,6-dideoxy-α, β-D-glucopyranose, was synthesized from 5 or 6 in 7 steps. The latter was readily converted into the corresponding 1-O-trichloroacetimidate. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Hou, Shujie,Kovac, Pavol
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experimental part
p. 1947 - 1952
(2009/04/04)
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- Exploring specificity of glycosyltransferases: synthesis of new sugar nucleotide related molecules as putative donor substrates
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We investigated the specificity of glycosyltransferases toward donor substrates in two complementary directions. First we prepared simple N-acetyl-α-d-glucosamine 1-diphosphates: methyl-(2-acetamido-2-deoxy-α-d-glucopyranosyl)-diphosphate, benzyl-(2-acetamido-2-deoxy-α-d-glucopyranosyl)-diphosphate, 4-phenylbutyl-(2-acetamido-2-deoxy-α-d-glucopyranosyl)-diphosphate , by the coupling of the corresponding activated alkyl phosphates with N-acetyl-α-d-glucosamine 1-phosphate. These diphosphates as well as 2-acetamido-2-deoxy-α-d-glucopyranose 1-diphosphate, tested as donors of N-acetylglucosamine in a reaction catalyzed by Neisseria meningitidis N-acetylglucosaminyltransferase (LgtA), proved to be devoid of activity. Evaluated as inhibitors, only 2-acetamido-2-deoxy-α-d-glucopyranose 1-diphosphate showed some inhibitory activity with an IC50 value of 7 mM. In the second approach, we prepared sugar nucleotide mimics having the diphosphate bridge replaced by the oxycarbonylaminosulfonyl linker. The surrogate of GDP-Fuc was synthesized as a 9:1 α/β anomeric mixture, in 40% yield, starting from chlorosulfonyl isocyanate, perbenzylated l-fucopyranose, and a guanosine derivative, protected on the exocyclic amine and secondary hydroxyl functions of ribose. Then two deprotection steps, hydrogenolysis and enzymatic hydrolysis catalyzed by penicillin G amidase afforded the target molecule to be tested as fucose donor with recombinant human α-(1→3/4)-fucosyltransferase (FucT-III). Tested as a 4:1 α/β anomeric mixture, both in the absence and in the presence of cationic cofactors, this new guanosine fucose conjugate proved to be ineffective. Its inhibitory activity toward FucT-III evaluated through a competition fluorescence assay was very poor (IC50 value of 20 mM). The surrogate of UDP-GlcNAc that was already known as its protected acetylated derivative, tested as N-acetylglucosamine donor with LgtA in the presence of Mn2+ turned out not to be active either.
- Khaled, Amira,Piotrowska, Olga,Dominiak, Katarzyna,Auge, Claudine
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p. 167 - 178
(2008/09/19)
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- Carbohydrate molecular recognition: A spectroscopic investigation of carbohydrate-aromatic interactions
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The physical basis of carbohydrate molecular recognition at aromatic protein binding sites is explored by creating molecular complexes between a series of selected monosaccharides and toluene (as a truncated model for phenylalanine). They are formed at low temperatures under molecular beam conditions, and detected and characterized through mass-selected, infrared ion depletion spectroscopy - a strategy which exploits the extraordinary sensitivity of their vibrational signatures to the local hydrogen-bonded environment of their OH groups. The trial set of carbohydrates, α- and β-anomers of glucose, galactose and fucose, reflects ligand fragments in naturally occurring protein-carbohydrate complexes and also allows an investigation of the effect of systematic structural changes, including the shape and extent of 'apolar' patches on the pyranose ring, removal of the OH on the exocyclic hydroxymethyl group, and removal of the aglycon. Bound complexes invariably form, establishing the general existence of intrinsic intermolecular potential minima. In most of the cases explored, comparison between recorded and computed vibrational spectra of the bound and free carbohydrates in the absence of solvent water molecules reveal that dispersion forces involving CH-π interactions, which promote little if any distortion of the bound carbohydrate, predominate although complexes bound through specific OH-π hydrogen-bonded interactions have also been identified. Since the complexes form at low temperatures in the absence of water, entropic contributions associated with the reorganization of surrounding water molecules, the essence of the proposed 'hydrophobic interaction', cannot contribute and other modes of binding drive the recognition of sugars by aromatic residues. Excitingly, some of the proposed structures mirror those found in naturally occurring protein-carbohydrate binding sites. the Owner Societies.
- Cristina Stanca-Kaposta,Gamblin, David P.,Screen, James,Liu, Bo,Snoek, Lavina C.,Davis, Benjamin G.,Simons, John P.
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p. 4444 - 4451
(2008/09/18)
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- Apoptolidin A: Total synthesis and partially glycosylated analogues
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The total synthesis of apoptolidin A is described employing an early glycosylation strategy. Strategic disconnections were chosen between C11-C12 (cross-coupling) and C19O-C1 (macrocyclization). The cis-selective glycosylation at C9-OH was achieved with the new SIBA protective group at O2/O3 of the L-glucose residue. Auxiliary substitutents at the 2-position of the 2-deoxy sugars were applied to form selectively the glycosidic linkages of the C27 disaccharide. The cross-coupling of the glycosylated northern half with the glycosylated southern half was achieved with Cu1-thiophene carboxylate. The macrocyclization of a trihydroxy carboxylic acid produced the 20-membered macrolide selectively. H2SiF6 was suitable for the final deprotection of the silyl ethers and the conversion of the C21 methylketal into the hemiketal. The synthetic flexibility of the approach was proven by the synthesis of some glycovariants.
- Wehlan, Hermut,Dauber, Mario,Fernaud, M. Teresa Mujica,Schuppan, Julia,Keiper, Sonja,Mahrwald, Rainer,Garcia, M.-Elisa Juarez,Koert, Ulrich
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p. 7378 - 7397
(2007/10/03)
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- Rapid synthesis of partially O-methylated alditol acetate standards for GC-MS: Some relative activities of hydroxyl groups of methyl glycopyranosides on Purdie methylation
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Mixtures containing the majority of partially O-methylated alditol acetates (PMAAs), necessary for the GC-MS based identification of glycosidic linkages in oligo- and polymeric structures were prepared. Rha, Fuc, Rib, Ara, Xyl, Man, Gal, and Glc were converted to their Me glycosides, and the products were progressively O-methylated using the Purdie reagent at 25°C. Resulting PMGs were assayed by TLC and at times that were optimum for formation of mono-O-methyl derivatives and later for higher degrees of methylation; they were converted to PMAAs, in a process incorporating NaB2H4 reduction. The majority of these can be used as standards for simultaneous identification of pyranosides and some furanosyl units particularly in heteropolysaccharides. The relative reactivities of OH-groups were determined by GC-MS as: Me α- and β-Glcp, HO-2 > HO-4 > HO-3 > HO-6, Me α- and β-Galp, HO-3 > HO-2 > HO-4 > HO-6, Me α-Manp, HO-3 > HO-2 > HO-4 > HO-6, Me β-Manp, HO-3 > HO-4 ≥ HO-6 > HO-2, Me α-Rhap, OH-3 > OH-2 > OH-4; Me αβ-Fucp, OH-2 > OH-3 > OH-4, and Me αβ-Xylp, OH-2 > OH-4 > OH-3. The results differ from those obtained with Haworth, Hakomori, and Ciucanu methylation techniques, although some similarities occurred with the more rapid Kuhn method.
- Sassaki, Guilherme L.,Gorin, Philip A. J.,Souza, Lauro M.,Czelusniak, Phelipe A.,Iacomini, Marcello
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p. 731 - 739
(2007/10/03)
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- Discovery of the chemical function of glycosidases: Design, synthesis, and evaluation of mass-differentiated carbohydrate libraries
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Equation presented. Discovery of the catalytic chemical function of the many putative glycosidases coded in genomes currently relies on individual testing of possible substrates, usually as their p-nitrophenol conjugate. Herein, we present an alternative chemical proteomics approach using a synthetic mass-differentiated heat-stable substrate library with mass spectrometry readout. Library components do not serve as reaction inhibitors and both primary and secondary enzyme substrates can be delineated.
- Yu, Yang,Ko, Kwang-Seuk,Zea, Corbin J.,Pohl, Nicola L.
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p. 2031 - 2033
(2007/10/03)
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- Glycolipids from Sponges. 13. Clarhamnoside, the First Rhamnosylated α-Galactosylceramide from Agelas clathrodes. Improving Spectral Strategies for Glycoconjugate Structure Determination
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Reinvestigation of the glycosphingolipid composition of the marine sponge Agelas clathrodes revealed the presence of a new tetraglycosylated α-galactoglycosphingolipid (1a), containing an unusual L-rhamnose unit in the sugar head. The structure of the new compound was elucidated using extensive 2D NMR studies. Because of the strong overlapping of the signals of the sugar protons in the 1H spectrum, 13C-coupled and 13C-decoupled phase-sensitive HMQC spectra were used to study the multiplicity of the overlapping signals. In addition, the absolute configuration of sugars was determined using a simple and efficient, yet underutilized CD method.
- Costantino, Valeria,Fattorusso, Ernesto,Imperatore, Concetta,Mangoni, Alfonso
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p. 1174 - 1179
(2007/10/03)
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- Total synthesis of apoptolidin
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A ring-size-selective macrolactonization and the early introduction of the saccharide portions are the main features of a total synthesis of the 20-membered macrolide apoptolidin (see formula), which induces apoptosis in rat glia cells transformed with oncogenes.
- Wehlan, Hermut,Dauber, Mario,Fernaud, M.-Teresa Mujica,Schuppan, Julia,Mahrwald, Rainer,Ziemer, Burkhard,Garcia, M.-Elisa Juarez,Koert, Ulrich
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p. 4597 - 4601
(2007/10/03)
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- Two new antifungal saponins from the Tibetan herbal medicine Clematis tangutica
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Bioassay-guided fractionation of the ethanol extract of the aerial parts of Clematis tangutica led to the isolation of two new antifungal triterpene saponins. Their structures were determined to be 3-O-α-L-arabinopyranosyl hederagenin 28-O-α-L-rhamnopyranosyl ester (1) and 3-O-β-D-glucopyranosyl-(1→4)-α-L-arabinopyranosyl hederagenin 28-O-α-L-rhamnopyranosyl ester (2) on the basis of spectral data and chemical evidence. Inhibitory activities of the two saponins against seven fungal strains were evaluated. Compounds 1 and 2 showed evident antifungal activity (MIA ≈ 2.5 μg/disc) against Saccharomyces cerevisiae, similar to the positive control amphotericin B and ordinary activities (MIA ≈ 10 μg/disc) against Penicillium avellaneum UC-4376, Candida glabrata, Trichosporon beigelii and Pyricularia oryzae. Compound 2 is a better antifungal agent than compound 1 against most of the fungal strains that were tested.
- Du, Zhizhi,Zhu, Na,Ze-Ren-Wang-Mu, Na,Shen, Yuemao
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p. 547 - 551
(2007/10/03)
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- Caminoside A, an antimicrobial glycolipid isolated from the marine sponge Caminus sphaeroconia.
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Extracts of the marine sponge Caminus sphaeroconia showed potent activity in a screen for bacterial type III secretion inhibitors. Bioassay guided fractionation of the extract led to the isolation of the novel antimicrobial glycolipid caminoside A (1). The structure of caminoside A was elucidated by analysis of spectroscopic data and chemical degradation.[structure: see text]
- Linington, Roger G,Robertson, Marilyn,Gauthier, Annick,Finlay, B Brett,van Soest, Rob,Andersen, Raymond J
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p. 4089 - 4092
(2007/10/03)
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- Induction of a preferred sense of twist in flexible diphenyls by carbohydrate scaffolds. Synthesis of two "naked" ellagitannin analogous
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The synthesis of "naked" ellagitannin analogues 1 and 2, having a preferred sense of twist of the diphenyl moiety, with a rhamnose and a glucose template, is reported. A clear induction in the chirality of the diphenyl moiety, mediated through a 10-membered ring via ester linkages, was observed. The chiral scaffold of glucose (diequatorial 2,3-hydroxyl groups) exerts a remarkable stronger atropdiastereoselective effect onto the diphenoyl group than the rhamnose ring (axial-equatorial 2,3-hydroxyl groups), according to the Schmidt-Haslam hypothesis.
- Capozzi,Ciampi,Delogu,Menichetti,Nativi
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p. 8787 - 8792
(2007/10/03)
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- Medicinal foodstuffs. XIII.1 saponin constituents with adjuvant activity from hyacinth bean, the seeds of Dolichos lablab L. (2) : Structures of lablabosides D, E, and F
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Following the characterization of lablabosides A, B, and C, new oleanane-type triterpene bisdesmosides, lablabosides D, E, and F, were isolated from the glycosidic fraction with adjuvant activity obtained from the seeds of Dolichos lablab L. (Leguminosae). Their chemical structures were elucidated on the basis of chemical and physicochemical evidence as follows : 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glucopyranosiduronic acid]-28-O-[6-O-(3-hydroxy-3-methylglutaroyl)-β-D-glucopyranosyl] 24-epi-hederagenin (lablaboside D), 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glucopyranosiduronic acid]-28-O-[α-L-rhamnopyranosyl (1→4)-α-L-rhamnopyranosyl (1→2)-β-D-glucopyranosyl] 24-epi-hederagenin (lablaboside E), 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glucopyranosiduronic acid]-28-O-[α-L-rhamnopyranosyl (1→4)-α-L-rhamnopyranosyl (1→2)-β-D-glucopyranosyl] oleanolic acid (lablaboside F).
- Komatsu, Hajime,Murakami, Toshiyuki,Matsuda, Hisashi,Yoshikawa, Masayuki
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p. 703 - 710
(2007/10/03)
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- Medicinal foodstuffs. VIII.1 Fenugreek seed. (2) : Structures of six new furostanol saponins, trigoneosides IVa, Va, Vb, VI, VIIb, and VIIIb, from the seeds of indian trigonella foenum-graecum L
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Following the characterization of trigoneosides Ia, Ib, IIa, IIb; IIIa, and IIIb, seven new steroidal saponins called trigoneosides IVa, Va, Vb, VI, VIIb, VIIIb, and IX were isolated from a medicinal foodstuff fenugreek seed, the seeds of Trigonella foenum-graecum L. (Leguminosae) originating from India. The structures of trigoneosides IVa, Va, Vb, VI, VIIb, and VIIIb were elucidated on the basis of chemical and physicochemical evidence.
- Yoshikawa, Masayuki,Murakami, Toshiyuki,Komatsu, Hajime,Yamahara, Johji,Matsuda, Hisashi
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p. 397 - 405
(2007/10/03)
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- Rapid access to rare natural pyranosides using 1,2-diacetal protected intermediates
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The synthesis of six rare methylpyranosides from common manno- and galacto-pyranoside starting materials has been achieved by the expedient use of 1,2-diacetal protecting group methodology highlighting its compatibility with a number of other common synthetic procedures.
- Ley, Steven V.,Owen, Dafydd R.,Wesson, Kieron E.
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p. 2805 - 2806
(2007/10/03)
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- Indonesian medicinal plants. XV. Chemical structures of five new resin- glycosides, merremosides a, b, c, d, and e, from the tuber of Merremia mammosa (Convolvulaceae)
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Five new resin-glycosides, named merremosides a (1), b (2), c (3), d (4), and e (5), were isolated from the tuber of Merremia mammosa (LOUR.) HALLIER f. (Convolvulaceae), an Indonesian medicinal plant. The structures of 1, 2, 3, 4, and 5 have been elucidated on the basis of chemical and physicochemical evidence, including syntheses of (11S)-(+)- and (11R)-(-)- jalapinolic acid (16b and 18b) and the glycosidic acid designated as merremoside i (6).
- Kitagawa, Isao,Baek, Nam In,Kawashima, Keiko,Yokokawa, Yoshihiro,Yoshikawa, Masayuki,Ohashi, Kazuyoshi,Shibuya, Hirotaka
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p. 1680 - 1692
(2007/10/03)
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- Indonesian medicinal plants. XVI. Chemical structures of four new resin- glycosides, merremosides f, g, h1, and h2, from the tuber of Merremia mammosa (Convolvulaceae)
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Four new resin-glycosides named merremosides f (6), g (7), h1 (8), and h2 (9) were isolated from the tuber of Merremia mammosa (Lour.) Hallier f. (Convolvulaceae), an Indonesian medicinal plant. Their chemical structures have been elucidated on the bases of their chemical and physicochemical properties.
- Kitagawa, Isao,Baek, Nam In,Yokokawa, Yoshihiro,Yoshikawa, Masayuki,Ohashi, Kazuyoshi,Shibuya, Hirotaka
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p. 1693 - 1699
(2007/10/03)
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- SYNTHESIS OF METHYL 3-ACETAMIDO-3,6-DIDEOXY-L-GALACTOPYRANOSIDES AND OF METHYL 3-ACETAMIDO-3,6-DIDEOXY-L-GULOPYRANOSIDES BY REDUCTION OF 3-ULOSE O-METHYLOXIMES
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Both anomers of methyl 3-acetamido-3,6-dideoxy-L-galactopyranoside and of methyl 3-acetamido-3,6-dideoxy-L-gulopyranoside have been prepared by conversion of easily accessible derivatives of methyl 6-deoxy-(α and β)-L-galactopyranosides into 3-uloses and reduction of the corresponding O-methyloximes.The 1H and 13C NMR data of the four 3-acetamido methyl glucosides have been given.
- Adinolfi, Matteo,Barone, Gaspare,Corsaro, Maria Michela,Lanzetta, Rosa,Mangoni, Lorenzo,Monaco, Pietro
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p. 913 - 928
(2007/10/02)
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- Total synthesis of calicheamicin γ1I. 1. Synthesis of the oligosaccharide fragment
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The first total synthesis of the calicheamicin γ1I oligosaccharide fragment in the form of its methyl glycoside (62) has been achieved. The synthetic challenge of the B-ring was recognized and studied initially, resulting in a novel and unique solution to the stereochemical problems posed involving a [3,3]-sigmatropic rearrangement of an allylic thionoimidazolide (111). This chemistry was initially worked out on a model for the ABC-ring system (47) and then successfully applied to the real system. The success of this synthesis has enabled the completion of the first synthesis of the natural product itself, calicheamicin γ1I (1), as will be described in the following papers in this issue.
- Groneberg,Miyazaki,Stylianides,Schulze,Stahl,Schreiner,Suzuki,Iwabuchi,Smith,Nicolaou
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p. 7593 - 7611
(2007/10/02)
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- Total Synthesis of Isokalafungins and Isonanaomycins
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The total synthesis of isokalafungins (2) and isonanaomycins (12), the first members of a nonnatural group of benzoisochromanquinone antibiotics hydroxylated only at C-6, is described.Pathway A (Scheme 1) yields the separated (+/-)-cis and -trans diastereomers of 2 and 12 and is especially suited for modifications of the dihydropyrane ring.On pathway B the chirality of C-1 is performed by using 3,4,6-trideoxy-α-L-glycero-hex-3-enopyranosid-2-ulose (22) as a main building block, for the first time synthesized from L-fucose (Scheme 2).According to Scheme 3, condensation of 22 with the intermediate 23 gives the new 6-hydroxylated variants (1S,3S,4S)-isonanaomycin D (30) and (1R,3R,4R)-isokalafungin (2).Pathway B favours modifications of the phenolic ring, which can strongly influence the spectrum of activity.Unexpectedly, the shifting of the hydroxy group from C-9 to C-6 changes the antibacterial properties unessentially. Key Words: Antibiotics, unnatural / Benzoisochromanquinones / Isokalafungins / Isonanaomycins
- Hoffmann, Bernd,Schoenebaum, Andreas,Lackner, Helmut
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p. 333 - 342
(2007/10/02)
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- Saponin and sapogenol. XLVIII. On the constituents of the roots of Glycyrrhiza uralensis FISCHER from Northeastern China. (2). Licorice-saponins D3, E2, F3, G2, H2, J2, and K2
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Following the characterization of licorice-saponins A3 (2), B2 (3), and C2 (4), the chemical structures of licorice-saponins D3 (5), E2 (6), F3 (7), G2 (8), H2 (9), J2 (10), and K2 (11), seven of the ten oleanane-type triterpene oligoglycosides isolated from the air-dried roots of Glycyrrhiza uralensis FISCHER collected in the northeastern part of China, were investigated. On the basis of chemical and physicochemical evidence, the structures of licorice-saponins D3, E2, F3, G2, H2, J2, and K2 have been determined to be expressed as 3β-[α-L-rhamnopyranosyl(1 → 2)-β-D-glucuronopyranosyl(1 → 2)-β-D-glucuronopyranosyloxy]-22β-acetoxyolean-12-en-30-oic acid (5), 3-O- [β-D-glucuronopyranosyl(1 → 2)-β-D-glucuronopyranosyl]glabrolide (6), 3- O-[α-L-rhamnopyranosyl(1 → 2)-β-D-glucuronopyranosyl(1 → 2)-β-D- glucuronopyranosyl]-11-deoxoglabrolide (7), 24-hydroxyglycyrrhizin (8), 3-O- [β-D-glucuronopyranosyl(1 → 2)-β-D-glucuronopyranosyl]liquiritic acid (9), 24-hydroxy-11-deoxoglycyrrhizin (10), and 3β-[β-D-glucuronopyranosyl(1 → 2)-β-D-glucuronopyranosyloxy]-24-hydroxyoleana-11,13(18)-dien-30-oic acid (11), respectively.
- Kitagawa,Hori,Sakagami,Zhou,Yoshikawa
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p. 1337 - 1345
(2007/10/02)
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- Enzymes in Oligosaccharide Synthesis: Active-Domain Overproduction, Specificity Study, and Synthetic Use of an α-1,2-Mannosyltransferase with Regeneration of GDP-Man
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The catalytic domain of a membrane-bound α-1,2-mannosyltransferase (ManT) from yeast has been overexpressed in E.coli, at a level of approximately 0.7-0.8 units per L with a specific activity of about 1 U/mg (based on α-methylmannoside) after purification
- Wang, Peng,Shen, Gwo-Jenn,Wang, Yi-Fong,Ichikawa, Yoshitaka,Wong, Chi-Huey
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p. 3985 - 3990
(2007/10/02)
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- Four new oleanene derivatives from the sseeds of Astragalus complanatus
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Four new methyl ester derivatives of oleanene glycosides (3-6) were isolated from the seeds of Astragalus complanatus R. BR. together with two known triterpene glycosides, astragaloside VIII methyl ester (1) and soyasaponin I methyl ester (2) after treatment with diazomethane during separation procedure. The structures of 3-6 were elucidated as 3-O-α-L-rhamnopyranosyl(1→2)-β-D-xylopyranosyl(1→2)-6-O-methy-β-D- glucuronopyranosyl-soyasapogenol B 22-O-β-D-glucopyranoside, 3-O-α-L-rhamnopyranosyl(1 →2)-β-D-galactopyranosyl(1→2)-6-O-methyl-β-D-glucuronopyranosyl-soy asapogenol B 22-O-β-D-glucopyranoside, 3-O-α-L-rhamnopyranosyl(1→2)-β-D-xylopyranosyl(1→2)-6-O-methyl-β-D -glucuronopyranosyl 3β,22β,24-trihydroxy-11-oxo-olean-12-ene and 3-O-α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl(1→2)-6-O-methyl-β-D-glucuronopyranosyl 3β,22β,24-trihydroxy-11-oxo-olean-12-ene, respectively.
- Cui,Sakai,Takeshita,Kinjo,Nohara
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p. 136 - 138
(2007/10/02)
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- Stereochemical studies on Esperamicins: Determination of the absolute configuration of hydroxyamino sugar fragment
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The β-D-gluco-hexopyranose configuration has been assigned for the hydroxyamino sugar fragment or esperamicin A. This determination concluded our study on the absolute configuration of the carbohydrate portion of esperamicins.
- Golik,Wong,Krishnan,Vyas,Doyle
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p. 1851 - 1854
(2007/10/02)
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- Nucleophilic displacement-reactions of the 4-sulfonyloxy group in derivatives having the D-manno configuration
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Methyl 2,3-di-O-benzoyl-6-deoxy-4-O-(p-tolylsulfonyl) and 4-O--α-D-mannopyranosides (9 and 10) were prepared by three different routes from methyl α-D-mannopyranoside (1).The analogous 4-sulfonyloxy derivatives having HO-2 and HO-3 free (14 and 15) were also synthesized from 1.Nucleophilic substitution of the sulfonyloxy group of 9, 10, 14, and 15 by potassium thiocyanate in N,N-dimethylformamide was attempted.Compounds 9 and 10 gave a mixture of solvolysis products: methyl 2,3-di-O-benzoyl-6-deoxy-α-D-talopyranoside (17), methyl 3,4-di-O-benzoyl-6-deoxy-α-D-talopyranoside (18), and methyl 2,4-di-O-benzoyl-6-deoxy-α-D-talopyranoside (19), which are evidently formed by intramolecular displacement of the 4-sulfonate by backside attack of the C-2 benzoyloxy substituent, followed by benzoyl migration.The structure of compounds 17-19 was established by spectroscopic analysis, and then chemically confirmed.Although compound 14 decomposed during the substitution reaction, the 4-p-nitrophenylsulfonyl derivative 15 gave a 2:1 mixture of the 4-thiocyano derivatives with inversion and retention of the C-4 configuration.
- Cicero, Daniel,Varela, Oscar,Lederkremer, Rosa M. de
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p. 295 - 308
(2007/10/02)
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- SYNTHESIS OF METHYL 2,6-DIDEOXY-β-D-ARABINO-, 3,6-DIDEOXY-β-D-RIBO-, AND 4,6-DIDEOXY-β-D-XYLO-HEXOPYRANOSIDES
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A convenient method is proposed for the synthesis of methyl 1,6-dideoxy-β-D-arabino-, 3,6-dideoxy-β-D-ribo-, and 4,6-dideoxy-β-D-xylo-hexopyranosides by the partial deoxygenation of methyl β-D-quinovopyranoside followed by liquid chromatography of the dideoxysugars.
- Evtushenko, E. V.
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p. 653 - 655
(2007/10/02)
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- Studies on the Constituents of Solanaceous Plants. XIII. A New Steroidal Glucuronide from Chinese Solanum lyratum
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A new glucuronide, (22R)-3β,16β,22,26-tetrahydroxycholest-5-ene 3-O-α-L-rhamnopyranosyl-(1->2)-β-D-glucuronopyranoside (1), was isolated from the aerial parts of Chinese Solanum lyratum THUNB.The structure of this new steroidal glucuronide was deduced by spectroscopic means and the identity of its aglycone was substantiated by comparison with an authentic sample derived from diosgenin acetate.Keywords - Solanaceae; Solanum lyratum; (22R)-3β,16β,22,26-tetrahydroxycholest-5-ene; rhamnosyl glucuronoside; diosgenin E,F-ring cleavage; aluminum chloride-acetic anhydride reaction.
- Yahara, Shoji,Ohtsuka, Michiko (nee Ikeda),Nakano, Kimiko,Nohara, Toshihiro
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p. 1802 - 1804
(2007/10/02)
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- SELECTIVE DEOXYGENATION VIA REGIOSELECTIVE THIOACYLATION OF NON-PROTECTED GLYCOPYRANOSIDES BY THE DIBUTYLTIN OXIDE METHOD
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Regioselective thioacylation of some non-protected glycopyranosides ( Me α-D-Glc, Me β-D-Glc, Me α-D-Xyl, Me β-D-Xyl ) was examined by the dibutyltin oxide method, using phenoxythiocarbonyl chloride as the thioacylating agent.This method gave the mono-thionocarbonates regioselectively in high yields.Acetylation of these thionocarbonates followed by deoxygenation with tributyltin hydride smoothly gave the corresponding deoxy derivatives, except for the primary thionocarbonates.Similar treatment of the pyranosides that have a cis-vicinal glycol ( Me α-D-Gal, Me β-D-Gal, Me β-L-Ara, and Ph α-L-Ara ) led to the formation of cyclic thionocarbonates, which on acetylation followed by olefination with trimethyl phosphite afforded the unsaturated derivatives in satisfactory yields.On deacetylation and subsequent hydrogenation over platinic oxide, they gave the corresponding dideoxy derivatives quantitatively.The compounds thus prepared were identified by analyses of their proton and carbon-13 nuclear magnetic resonance spectra.Keywords - glycopyranoside; regioselective thioacylation; dibutyltin oxide; deoxygenation; cis-vicinal glycol; thionocarbonate; cyclic thionocarbonate; deoxy, dideoxy sugar; unsaturated sugar; 13C-NMR
- Haque, Ekramul Mohammed,Kikuchi, Tohru,Kanemitsu, Kimihiro,Tsuda, Yoshisuke
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p. 1016 - 1029
(2007/10/02)
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- STEROIDS OF THE SPIROSTAN AND FUROSTAN SERIES FROM PLANTS OF THE GENUS Allium. II. THE STRUCTURE OF ALLIOSPIROSIDE B FROM Allium cepa
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A new steroid glycoside - alliospiroside B (I) - has been isolated from the collective fruit of Allium cepa L.On the basis of chemical transformations and with the aid of physicochemical measurements it has been established that compound (I) has the structure of (25S)spirost-5-ene-1β,3β-diol 1-O- 2)-β-D-galactopyranoside.Compound (I) C39H62O3, mp 200-202 deg C (from ethanol), D20 -110.9 +/- 2 deg (c 1.01; pyridine) was obtained by extracting the collective fruit of A. cepa with ethanol followed by the column chromatographic separation of the combined glycosides on silica gel.The acid hydrolysis of (I) gave (25S)-ruscogenin (II), C27H42O4, mp 189-191 deg C, D23 -104.1 +/- 2 deg (c 0.98; pyridine).The 1H and 13C NMR spectra are given for both compounds and the IR spectrum for compound (I).
- Kravets, C. D.,Vollerner, Yu. S.,Gorovits, M. B.,Shashkov, A. S.,Abubakirov, N. K.
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p. 553 - 556
(2007/10/02)
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- CHARACTERIZATION OF 6-DEOXY-D-ALTRITOL IN THE CELL-WALL POLYSACCHARIDE OF Nocardia asteroides R 399
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A polyol, found in the cell-wall of Nocardia asteroides R 399 as a component of a neutral polysaccharide mainly composed of D-arabinose and D-galactose, was identified by mass spectrometry, paper chromatography, thin-layer chromatography, and gas chromatography as 6-deoxy-D-altritol.
- Voiland, Annie,Michel, Georges
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p. 283 - 288
(2007/10/02)
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