- Synthesis of 1,2,3-triazolyl analog of Neisseria meningitidis A capsular polysaccharide
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Towards constructing a stable, non-hydrolyzable linkage for Neisseria meningitidis type A (MenA) polysaccharide, the phosphate bridge of its (1→6)-linked 2-acetamido-2-deoxy-α-D-mannopyranosyl phosphate repeating unit was replaced by a triazolyl analog using Cu(I) catalyzed click reaction. The synthesis involved anomeric azidation of N-acetyl-D-mannosamine derivative from its acetate precursor using stoichiometric amount of FeCl3 and one-pot synthesis of precursors for di- and tri- triazolyl saccharides with an azidoethyl spacer at the reducing end for bioconjugation.
- Vangala, Madhuri,Hotha, Srinivas
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- Synthesis of 2-azido-2-deoxy- and 2-acetamido-2-deoxy-D-manno derivatives as versatile building blocks
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Reported herein is the synthesis of a number of building blocks of 2-amino-2-deoxy-D-mannose from common D-glucose precursors.
- Alex, Catherine,Visansirikul, Satsawat,Zhang, Yongzhen,Yasomanee, Jagodige P.,Codee, Jeroen,Demchenko, Alexei V.
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- Modular hydroxyamide and thioamide pyranoside-based ligand library from the sugar pool: New class of ligands for asymmetric transfer hydrogenation of ketones
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A large library of pyranoside-based hydroxyamide and thioamide ligands has been synthesized for asymmetric transfer hydrogenation in an attempt to expand the scope of the substrates to cover a broader range of challenging heteroaromatic and aryl/fluoroalkyl ketones. These ligands have the advantage that they are prepared from commercial D-glucose, D-glucosamine and α-amino acids, inexpensive natural chiral feedstocks. By carefully selecting the ligand components (substituents/configurations at the amide/thioamide moiety, the position of amide/thioamide group and the configuration at C-2), we found that pyranoside-based thioamide ligands provided excellent enantioselectivities (in the best cases, ees of >99% were achieved) in a broad range of ketones, including the less studied heteroaromatics and challenging aryl/fluoroalkyls. Note that both enantiomers of the reduction products can be obtained with excellent enantioselectivities by simply changing the absolute configuration of the thioamide substituent.
- Coll, Mercè,Pàmies, Oscar,Diéguez, Montserrat
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supporting information
p. 2293 - 2302
(2014/07/21)
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- Carbohydrate-based N-heterocyclic carbenes for enantioselective catalysis
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Versatile syntheses of C2-linked and C2-symmetric carbohydrate-based imidazol(in)ium salts from functionalised amino-carbohydrate derivatives are reported. The novel NHCs were ligated to [Rh(COD)Cl]2 and evaluated in Rh-catalysed asymmetric hydrosilylation of ketones with good yields and promising enantioselectivities.
- Henderson, Alexander S.,Bower, John F.,Galan, M. Carmen
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supporting information
p. 9180 - 9183
(2015/02/19)
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- Chemoenzymatic synthesis of CMP-N-acetyl-7-fluoro-7-deoxy-neuraminic acid
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7-Fluoro sialic acid was prepared and activated as cytidine monophosphate (CMP) ester. The synthesis started with d-glucose, which was efficiently converted into N-acetyl-4-fluoro-4-deoxy-d-mannosamine. Aldolase catalyzed transformation yielded the corres
- Hartlieb, Sina,Guenzel, Almut,Gerardy-Schahn, Rita,Muenster-Kuehnel, Anja K.,Kirschning, Andreas,Draeger, Gerald
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p. 2075 - 2082
(2008/12/21)
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- Chemoenzymatic synthesis of GDP-azidodeoxymannoses: Non-radioactive probes for mannosyltransferase activity
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GDP-2-, 3-, 4- or 6-azidomannoses can be successfully prepared from the corresponding azidomannose-1-phosphates and GTP using the enzyme GDP-Mannosepyrophosphorylase (GDP-ManPP) from Salmonella enterica and may serve as useful probes for mannosyltransferase activity. The Royal Society of Chemistry.
- Marchesan, Silvia,Macmillan, Derek
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supporting information; scheme or table
p. 4321 - 4323
(2009/03/12)
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- A concise synthesis of 4-nitrophenyl 2-azido-2-deoxy- and 2-acetamido-2-deoxy-d-mannopyranosides
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4-Nitrophenyl 3,4,6-tri-O-acetyl-2-azido-2-deoxy-α- and β-d-mannopyranosides were prepared from methyl 4,6-O-benzylidene-α-d- glucopyranoside and 1,3,4,6-tetra-O-acetyl-α-d-glucopyranose, respectively. Chemoselective reduction of both azides with hydrogen sulfide readily afforded 4-nitrophenyl 2-acetamido-4,6-di-O-acetyl-2-deoxy-α-d- and -β-d-mannopyranosides in higher yields than reduction with triphenylphosphine or a polymer-supported triarylphosphine. Subsequent de-O-acetylation yielded 4-nitrophenyl 2-acetamido-2-deoxy-α-d- mannopyranoside and 4-nitrophenyl 2-acetamido-2-deoxy-β-d-mannopyranoside in 20% and 44% overall yields, respectively.
- Popelová, Alena,Kefurt, Karel,Hlavá?ková, Martina,Moravcová, Jitka
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p. 161 - 166
(2007/10/03)
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- Reactions of Some Pyranoside Diol Monotriflates with Nucleophiles and Bases
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Reaction of pyranoside diol (equatorial) monotriflates with soft, nonbasic nucleophiles is a useful way to make axial heteroatom-substituted and "epimerized" pyranosides, particularly where a fused acetal ring inhibits ring contraction.Among the substrates examined (1,2,3,4,35), only 4 shows a strong tendency to give ring-contracted products.The reaction of 1-3 with more basic nucleophiles (F(1-), t-BuO(1-)) leads to the anhydrosugars 8, 25, and 26, respectively.The SN2 reaction of 35 with tetra n-butylammonium iodide forms the basis for a new synthesis of the Cerny epoxide 32.
- Knapp, Spencer,Naughton, Andrew B. J.,Jaramillo, Carlos,Pipik, Brenda
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p. 7328 - 7334
(2007/10/02)
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- SYNTHESIS OF A TRISACCHARIDE COMPONENT OF THE CAPSULAR POLYSACCHARIDE OF Streptococcus pneumoniae TYPE 19F
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2-O--α,β-L-rhamnopyranose, a structural component of the capsular polysaccharide of Streptococcus pneumoniae type 19F, has been synthesized by sequential glycosylation reactions using the gl
- Sugawara, Tamio,Igarashi, Kikuo
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p. 195 - 208
(2007/10/02)
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