- First total synthesis of 5'-O-α-d-glucopyranosyl tubercidin
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The first total synthesis of 50-O-α-d-glucopyranosyl tubercidin was successfully developed. It is a structurally unique disaccharide 7-deazapurine nucleoside exhibiting fungicidal activity, and was isolated from blue-green algae. The total synt
- Ouyang, Wenliang,Huang, Haiyang,Yang, Ruchun,Ding, Haixin,Xiao, Qiang
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Read Online
- DIRECT O-GLYCOSYL TRICHLOROACETIMIDATE FORMATION. NUCLEOPHILICITY OF THE ANOMERIC OXYGEN ATOM
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Tetra-O-benzylglucose 1 and trichloroacetonitrile afford in a base catalyzed, fast, and reversible reaction the β-O-glycosyl imidate 3-β, which is transformed slowly into the α-isomer 3-α.Both results, the reactivity differences of 2α,β and the stability
- Schmidt, Richard R.,Michel, Josef
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Read Online
- Synthesis of a derivative of a-D-Glcp(1→2)-D-Galf suitable for further glycosylation and of a-D-Glcp(1→2)-D-Gal, a disaccharide fragment obtained from varianose
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The presence of galactofuranoyl units in infectious microorganisms has prompted the study of the metabolic pathways involved in their incorporation in glycans. Although much progress has been made with respect to the biosynthesis of β-D-Galf-containing glycoconjugates, the mechanisms by which α-D-Galf units are incorporated remain unclear. Penicillium varians is a non-pathogenic fungus that produces varianose, a polysaccharide containing both a- and β-D-Galf units, which can be used as a model for biosynthetic studies on α-D-Galf incorporation. Synthetic oligosaccharide fragments related to varianose are useful as potential substrates or standards for characterization of the a-galactofuranosyl transferases. In this paper we report a straightforward procedure for the synthesis of a-D-Glcp(1→2)-D-Gal (1) and the use of this compound to monitor the natural disaccharide released from varianose by mild acid degradation. The synthesis, performed by the glycosylaldonolactone approach, involved a glucosylgalactofuranose derivative, suitable for the synthesis of higher oligosaccharides with an internal D-Galf.
- Marino, Carla,Lima, Carlos,Marino, Karina,De Lederkremer, Rosa M.
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Read Online
- Stereoselective O-Glycosylations by Pyrylium Salt Organocatalysis**
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Despite many years of invention, the field of carbohydrate chemistry remains rather inaccessible to non-specialists, which limits the scientific impact and reach of the discoveries made in the field. Aiming to increase the availability of stereoselective
- Holmstr?m, Thomas,Nielsen, Michael Martin,Pedersen, Christian Marcus
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supporting information
(2021/12/30)
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- Synthesis of nature product kinsenoside analogues with anti-inflammatory activity
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Kinsenoside is the major bioactive component from herbal medicine with a broad range of pharmacological functions. Goodyeroside A, an epimer of kinsenoside, remains less explored. In this report we chemically synthesized kinsenoside, goodyeroside A and their analogues with glycan variation, chirality inversion at chiral center(s), and bioisosteric replacement of lactone with lactam. Among these compounds, goodyeroside A and its mannosyl counterpart demonstrated superior anti-inflammatory efficacy. Furthermore, goodyeroside A was found to suppresses inflammatory through inhibiting NF-κB signal pathway, effectively. Structure-activity relationship is also explored for further development of more promising kinsenoside analogues as drug candidates.
- Song, Wei,Sun, Yong,Xu, Lintao,Sun, Yajing,Li, Tianlu,Peng, Peng,Lou, Hongxiang
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supporting information
(2020/12/02)
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- Self-Promoted Glycosylation for the Synthesis of β-N-Glycosyl Sulfonyl Amides
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N-Glycosyl N-sulfonyl amides have been synthesized by a self-promoted glycosylation, i. e. without any catalysts, promotors or additives. When the reactions were carried out at lower temperatures a mixture of N- and O-glycosides were observed, where the latter rearranged to give the β-N-glycosides at elevated temperatures. By this method sulfonylated asparagine derivatives can be selectively β-glycosylated in high yields by trichloroacetimidate glycosyl donors of different reactivity including protected glucosamine derivatives. The chemoselectivity in the glycosylations as well as the rearrangements from O-glycosides to β-N-glycosides gives information of the glycosylation mechanism. This method gives access to glycosyl sulfonyl amides under mild conditions.
- Ma?a, Patrycja,Pedersen, Christian Marcus
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supporting information
p. 5685 - 5689
(2021/08/30)
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- A "traceless" Directing Group Enables Catalytic SN2 Glycosylation toward 1,2- cis-Glycopyranosides
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Generally applicable and stereoselective formation of 1,2-cis-glycopyranosidic linkage remains a long sought after yet unmet goal in carbohydrate chemistry. This work advances a strategy to this challenge via stereoinversion at the anomeric position of 1,2-trans glycosyl ester donors. This SN2 glycosylation is enabled under gold catalysis by an oxazole-based directing group optimally tethered to a leaving group and achieved under mild catalytic conditions, in mostly excellent yields, and with good to outstanding selectivities. The strategy is also applied to the synthesis of oligosaccharides.
- Fu, Yue,Liu, Peng,Ma, Xu,Zhang, Liming,Zheng, Zhitong,Zhu, Xijun
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p. 11908 - 11913
(2021/08/20)
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- Glucosylpolyphenols as Inhibitors of Aβ-Induced Fyn Kinase Activation and Tau Phosphorylation: Synthesis, Membrane Permeability, and Exploratory Target Assessment within the Scope of Type 2 Diabetes and Alzheimer's Disease
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Despite the rapidly increasing number of patients suffering from type 2 diabetes, Alzheimer's disease, and diabetes-induced dementia, there are no disease-modifying therapies that are able to prevent or block disease progress. In this work, we investigate the potential of nature-inspired glucosylpolyphenols against relevant targets, including islet amyloid polypeptide, glucosidases, and cholinesterases. Moreover, with the premise of Fyn kinase as a paradigm-shifting target in Alzheimer's drug discovery, we explore glucosylpolyphenols as blockers of Aβ-induced Fyn kinase activation while looking into downstream effects leading to Tau hyperphosphorylation. Several compounds inhibit Aβ-induced Fyn kinase activation and decrease pTau levels at 10 μM concentration, particularly the per-O-methylated glucosylacetophloroglucinol and the 4-glucosylcatechol dibenzoate, the latter inhibiting also butyrylcholinesterase and β-glucosidase. Both compounds are nontoxic with ideal pharmacokinetic properties for further development. This work ultimately highlights the multitarget nature, fine structural tuning capacity, and valuable therapeutic significance of glucosylpolyphenols in the context of these metabolic and neurodegenerative disorders.
- De Matos, Ana M.,Blázquez-Sánchez, M. Teresa,Bento-Oliveira, Andreia,De Almeida, Rodrigo F. M.,Nunes, Rafael,Lopes, Pedro E. M.,MacHuqueiro, Miguel,Cristóv?o, Joana S.,Gomes, Cláudio M.,Souza, Cleide S.,El Idrissi, Imane G.,Colabufo, Nicola A.,Diniz, Ana,Marcelo, Filipa,Oliveira, M. Concei??o,López, óscar,Fernandez-Bola?os, José G.,D?twyler, Philipp,Ernst, Beat,Ning, Ke,Garwood, Claire,Chen, Beining,Rauter, Amélia P.
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p. 11663 - 11690
(2020/11/26)
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- Synthesis of photolabile group protected anomeric acetals and its application in carbohydrate synthesis with the assistance of continuous flow photo-reactor
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Selective deprotection of photolabile anomeric 2-nitrobenzyl acetals was achieved using continuous flow photo-reactor (UV radiation at 355 nm) in methanol-water. Various protecting groups such as acetyl, benzyl, benzoyl, benzylidine, TBS, etc. were found to be highly stable during the photolysis.
- Tiwari, Varsha,Badavath, Vishnu Nayak,Singh, Adesh Kumar,Kandasamy, Jeyakumar
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p. 227 - 236
(2020/03/18)
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- Chemoselectivity in Self-Promoted Glycosylation: N- vs. O-Glycosylation
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Self-promoted glycosylation using trichloroacetimidates and sulfonamides have recently been developed. In this communication, we study the parameters controlling the chemoselectivity between a nucleophilic sulfonamide nitrogen and an alcohol, both contain
- Pedersen, Christian Marcus,Pinna, Alessandro
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supporting information
(2020/06/23)
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- Visible-Light-Mediated β-C(sp3)-H Amination of Glycosylimidates: En Route to Oxazoline-Fused/Spiro Nonclassical Bicyclic Sugars
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A straightforward route has been developed for the diastereoselective synthesis of nonclassical conformationally constrained oxazoline-fused and spiro bicyclic sugars bearing a quaternary center via selective β-C-H amination of appropriately positioned gl
- Shaw, Mukta,Kumar, Amit
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supporting information
(2019/05/08)
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- Self-promoted and stereospecific formation of N-glycosides
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A stereoselective and self-promoted glycosylation for the synthesis of various N-glycosides and glycosyl sulfonamides from trichloroacetimidates is presented. No additional catalysts or promoters are needed in what is essentially a two-component reaction. When α-glucosyl trichloroacetimidates are employed, the reaction resulted in the stereospecific formation of the corresponding β-N-glucosides in high yields at ambient conditions. On the other hand, when equatorial glucosyl donors were used, the stereospecificity decreased and resulted in a mixture of anomers. By NMR-studies, it was concluded that this decrease in stereospecificity was due to an, until now, unpresented anomerization of the trichloroacetimidate under the very mildly acidic conditions. The mechanism and kinetics of the glycosylations have been studied by NMR-experiments, which gave an insight into the activation of trichloroacetimidates, suggesting an SNi-like mechanism involving ion pairs. The scope of glycosyl donors and sulfonamides was found to be very broad including popular N-protective groups and common glycosyl donors of various reactivity. Peracetylated GlcNAc trichloroacetimidate could be used without the need for any promotors or additives and a tyrosine side chain was glycosylated as an N-glycosyl carbamate. The N-carbamates and the N-sulfonyl groups functioned as orthogonal protective groups of the N-glycoside and hence allowed further N-functionalization without risking mutarotation of the N-glycoside. The N-glycosylation was also performed on a gram scale, without a drop in stereoselectivity nor yield.
- Nielsen, Michael Martin,Ma?a, Patrycja,Baldursson, Eirikur Pórir,Pedersen, Christian Marcus
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p. 5299 - 5307
(2019/05/29)
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- A Simple Method for the Preparation of Stainless and Highly Pure Trichloroacetimidates
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We describe a method for obtaining various allylic, benzylic, and glucosyl 2,2,2-trichloroacetimidates (TCAIs) as stainless liquids or solids at the crude stage. The general synthetic method for the preparation of TCAIs often leads to stained products, and further purification of crude TCAIs causes decomposition due to their instability. In the described method, we use a solvent that barely dissolves the reactant, providing stainless and sufficiently pure TCAIs without requiring a purification step. Furthermore, the reaction mixture is turbid at the beginning and clear at the end, allowing us to monitor the progress of the reaction visually.
- Ikeuchi, Kazutada,Murasawa, Kentaro,Yamada, Hidetoshi
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supporting information
p. 1308 - 1312
(2019/06/20)
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- An Empirical Understanding of the Glycosylation Reaction
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Reliable glycosylation reactions that allow for the stereo- and regioselective installation of glycosidic linkages are paramount to the chemical synthesis of glycan chains. The stereoselectivity of glycosylations is exceedingly difficult to control due to the reaction's high degree of sensitivity and its shifting, simultaneous mechanistic pathways that are controlled by variables of unknown degree of influence, dominance, or interdependency. An automated platform was devised to quickly, reproducibly, and systematically screen glycosylations and thereby address this fundamental problem. Thirteen variables were investigated in as isolated a manner as possible, to identify and quantify inherent preferences of electrophilic glycosylating agents (glycosyl donors) and nucleophiles (glycosyl acceptors). Ways to enhance, suppress, or even override these preferences using judicious environmental conditions were discovered. Glycosylations involving two specific partners can be tuned to produce either 11:1 selectivity of one stereoisomer or 9:1 of the other by merely changing the reaction conditions.
- Chatterjee, Sourav,Moon, Sooyeon,Hentschel, Felix,Gilmore, Kerry,Seeberger, Peter H.
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supporting information
p. 11942 - 11953
(2018/09/27)
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- Synthesis of Oxaphosphinane-Based Pseudodisaccharides
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The synthesis of pseudodisaccharides based on an oxaphosphinane heterocycle is described. Disaccharide mimetics 5 and 6 were readily obtained through glycosylation of a hydroxy group with appropriately protected furanosyl or pyranosyl carbohydrates using
- Babouri, Rachida,Clarion, Ludovic,Rolland, Marc,Van der Lee, Arie,Kabouche, Zahia,Volle, Jean-No?l,Virieux, David,Pirat, Jean-Luc
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p. 5357 - 5369
(2017/10/06)
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- Carbohydrate-lipid constructs and their use in preventing or treating viral infection
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The invention relates to selected carbohydrate-lipid constructs and their use as mimics of ligands for receptors expressed by virus. In particular, the invention relates to the use of selected carbohydrate-lipid constructs in methods of inhibiting virus infection and/or promoting clearance of virus from infected subjects. Carbohydrate-lipid constructs selected for use in these methods where the virus is Human Immunodeficiency Virus (HIV) are provided.
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Page/Page column 26
(2016/01/30)
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- Design and synthesis of novel inhibitor containing 5-thiosugar
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The invention provides novel glycosidase inhibitor containing 5-thiosugar. (See the formula in the description), wherein X represents O or S, Y represents O or S, R represents Me, Et and other chainlike alkyl groups or phenyl group, methoxy methyl and oth
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Paragraph 0020; 0045; 0046
(2017/05/19)
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- Glycoconjugates and use thereof as vaccine against Shigella flexneri serotype 3a and X
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The present invention relates to compounds derived from sugars which reproduce the epitopes of Shigella flexneri serotypes 3a and X and to the use thereof for the preparation of vaccine compositions. More specifically, the subject matter of the present in
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Page/Page column 89-90
(2014/09/03)
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- Exploring glycosylation reactions under continuous-flow conditions
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The industrial development of carbohydrate-based drugs is greatly thwarted by the typical challenges inherent in oligosaccharide synthesis. The practical advantages of continuous-flow synthesis in microreactors (high reproducibility, easy scalability, and fast reaction optimization) may offer an effective support to make carbohydrates more attractive targets for drug-discovery processes. Here we report a systematic exploration of the glycosylation reaction carried out under microfluidic conditions. Trichloroacetimidates and thioglycosides have been investigated as glycosyl donors, using both primary and secondary acceptors. Each microfluidic glycosylation has been compared with the corresponding batch reaction, in order to highlight advantages and drawbacks of microreactors technology. As a significant example of multistep continuous-flow synthesis, we also describe the preparation of a trisaccharide by means of two consecutive glycosylations performed in interconnected microreactors.
- Cancogni, Damiano,Lay, Luigi
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supporting information
p. 2873 - 2878
(2015/01/16)
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- Compositions comprising noribogaine and an excipient to facilitate transport across the blood brain barrier
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This invention relates generally to compositions comprising noribogaine and an excipient to facilitate transport across the blood brain barrier.
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Page/Page column 30; 31
(2014/02/16)
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- Combined Lewis acid and Br?nsted acid-mediated reactivity of glycosyl trichloroacetimidate donors
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Biomimetic conditions for a synthetic glycosylation reaction, inspired by the highly conserved functionality of carbohydrate active enzymes, were explored. At the outset, we sought to generate proof of principle for this approach to developing catalytic systems for glycosylation. However, control reactions and subsequent kinetic studies showed that a stoichiometric, irreversible reaction of the catalyst and glycosyl donor was occurring, with a remarkable rate variance depending upon the structure of the carboxylic acid. It was subsequently found that a combination of Br?nsted acid (carboxylic acid) and Lewis acid (MgBr2) was unique in catalyzing the desired glycosylation reaction. Thus, it was concluded that the two acids act synergistically to catalyze the desired transformation. The role of the catalytic components was tested with a number of control reactions and based on these studies a mechanism is proposed herein.
- Gould, Nathan D.,Liana Allen,Nam, Brandon C.,Schepartz, Alanna,Miller, Scott J.
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supporting information
p. 36 - 42
(2013/11/19)
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- Efficient α-mannosylation of phenols: The role of carbamates as scavengers for activated glycosyl donors
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The boron trifluoride activation of trichloroacetimidate donors was found to be an efficient method for the α-mannosylation of tyrosine-containing acceptors. Most notably, these conditions are compatible with the commonly used carbamate protecting groups, whereas trichloroacetimidate activation with trimethylsilyl triflate or the use of glycosyl sulfoxides led to diminished yields in the presence of carbamates. In these cases, the competing reaction of the activated donors with the carbamate group was identified as a problematic side reaction. Taking advantage of this reactivity, various glycosyl carbamates were generated for the first time under non-acidic glycosylation conditions by reaction of different Boc-protected amino acids and dipeptides with glycosyl sulfoxides under triflic anhydride activation. Georg Thieme Verlag Stuttgart · New York.
- Schüler, Peter,Fischer, Sebastiann.,Marsch, Michael,Oberthür, Markus
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- Fluorine-directed β-galactosylation: Chemical glycosylation development by molecular editing
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Validation of the 2-fluoro substituent as an inert steering group to control chemical glycosylation is presented. A molecular editing study has revealed that the exceptional levels of diastereocontrol in glycosylation processes by using 2-fluoro-3,4,6-tri-O-benzyl glucopyranosyl trichloroacetimidate (TCA) scaffolds are a consequence of the 2R,3S,4S stereotriad. This study has also revealed that epimerization at C4, results in a substantial enhancement in β-selectivity (up to β/α 300:1). Copyright
- Durantie, Estelle,Bucher, Christoph,Gilmour, Ryan
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supporting information; experimental part
p. 8208 - 8215
(2012/08/27)
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- Monosaccharidic mimetics of the sialyl LewisX tetrasaccharide based on 2,7-dihydroxynaphthalene
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A potential monosaccharidic mimetic of the sialyl LewisX tetrasaccharide (sLeX) was identified based on an in silico docking study using the crystal structure of an E-selectin-sLeX complex. The chemical synthesis of the mimetic in an ortho-selective C-glycosylation is described. This compound and two close analogues were evaluated in a cell-based selectin binding assay where none of the tested mimetics showed an IC 50 below 1mM. This result can be explained by an unexpected 1C4 conformation of the mannosyl residue which precludes the required binding of the Ca2+-ion in E-selectin.
- Weck, Stefan,Frank, Martin,Hamann, Alf,Opatz, Till
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p. 134 - 148
(2013/09/24)
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- Dye-sensitized photooxygenation of 2,5-Bis(glycosyl)furans
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The dye-sensitized photooxygenation of 2,5-bis(glycosyl)furans followed by warming up to r.t. provides 1,1'- linked disaccharides separated by a functionalized spacer. Asymmetrical disubstituted glycosyl furans give the corresponding Bayer-Villiger type-r
- Cermola, Flavio,Iesce, Maria R.,Astarita, Anna,Passananti, Monica
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scheme or table
p. 309 - 314
(2012/05/20)
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- A mild ligand-free iron-catalyzed liberation of alcohols from allylcarbonates
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Different from most carbonates the allyloxy carbonyl protecting group can be cleaved under neutral conditions using metal catalysis. However, most of the catalysts employed to date are based upon precious metals. Herein we present two protocols for the mild Fe-catalyzed liberation of alcohols from allylcarbonates that are characterized by broad functional group tolerance and exclusive chemoselectivity.
- Dieskau, Andre P.,Plietker, Bernd
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supporting information; experimental part
p. 5544 - 5547
(2011/12/05)
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- β-selective C-mannosylation of electron-rich phenols
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The reaction of tetra-O-benzylmannosyl trichloroacetimidate with electron-rich phenols in the presence of TMSOTf surprisingly leads to the exclusive formation of aryl β-C-glycosides while a preference for the -anomer could be observed with other Lewis aci
- Weck, Stefan,Opatz, Till
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supporting information; experimental part
p. 2393 - 2398
(2010/09/06)
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- Glycosylation catalyzed by a chiral bronsted acid
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"Chemical equation presented" The use of a chiral Bronsted acid catalyst for the activation of trichloroacetimidate glycosyl donors has been demonstrated for the first time. In toluene the chirality of the acid catalyst is seen to influence the stereochem
- Cox, Daniel J.,Smith, Martin D.,Fairbanks, Antony J.
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supporting information; experimental part
p. 1452 - 1455
(2010/06/20)
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- Fluorine-directed glycosylation
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Everything's under control: A stabilizing fluorine electrostatic interaction has been exploited to control oxonium ion conformation in 2-fluoropyranose derivatives (see scheme). When matched with the inductive nature of the protecting groups, the glycosyl
- Bucher, Christoph,Gilmour, Ryan
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supporting information; experimental part
p. 8724 - 8728
(2011/01/06)
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- Total synthesis of the fully lipidated glycosylphosphatidylinositol (GPI) anchor of malarial parasite Plasmodium falciparum
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We report a new and convergent strategy for the total synthesis of fully lipidated glycosylphosphatidylinositol (GPI) anchor, the major pro-inflammatory factor of malarial parasite (Plasmodium falciparum). The key features of our approach include, the acc
- Ali, Asif,Vishwakarma, Ram A.
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scheme or table
p. 4357 - 4369
(2010/07/06)
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- CARBOHYDRATE-LIPID CONSTRUCTS AND THEIR USE IN PREVENTING OR TREATING VIRAL INFECTION
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The invention relates to selected carbohydrate-lipid constructs and their use as mimics of ligands for receptors expressed by virus. In particular, the invention relates to the use of selected carbohydrate-lipid constructs in methods of inhibiting virus infection and/or promoting clearance of virus from infected subjects. Carbohydrate-lipid constructs selected for use in these methods where the virus is Human Immunodeficiency Virus (HIV) are provided.
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- Concise synthesis of chafurosides A and B
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The regioselective synthesis of chafurosides A (1) and B (2) from the same methyl ketone 5 was accomplished using a novel protecting group strategy. Both flavone rings were constructed from β-diketone intermediate 4, which was readily obtained by condensation of an acyl donor and ketone 5. Construction of the dihydrofuran ring was achieved via an intramolecular Mitsunobu reaction.
- Furuta, Takumi,Nakayama, Miho,Suzuki, Hirotaka,Tajimi, Hiroko,Inai, Makoto,Nukaya, Haruo,Wakimoto, Toshiyuki,Kan, Toshiyuki
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supporting information; experimental part
p. 2233 - 2236
(2009/10/02)
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- Silver(I) tetrafluoroborate as a potent promoter for chemical glycosylation
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We have identified silver tetrafluoroborate (AgBF4) as an excellent promoter for the activation of various glycosyl donors including glycosyl halides, trichloroacetimidates, and thioimidates. Easy handling and no requirement for azeotropic dehydration prior to application makes AgBF4 especially beneficial in comparison to the commonly used AgOTf. Selective activation of glycosyl halides or thioimidates over thioglycosides or n-pentenyl glycosides, including simple sequential one-pot syntheses, has also been demonstrated. Versatility of glycosyl thioimidates was further explored by converting these intermediates into a variety of other classes of glycosyl donors.
- Kaeothip, Sophon,Pornsuriyasak, Papapida,Demchenko, Alexei V.
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p. 1542 - 1545
(2008/09/19)
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- Some aspects of selectivity in the reaction of glycosyl donors
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Some advantages, disadvantages, and anomalies of various donors in glycosidations are discussed. By studying several two-component donor/acceptor-diol reactions, it is shown that regiopreferences are not very sensitive to the type of donor used. However,
- Uriel, Clara,Gomez, Ana M.,Lopez, J. Cristobal,Fraser-Reid, Bert
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p. 665 - 675
(2007/10/03)
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- A new approach to construct full-length glycosylphosphatidylinositols of parasitic protozoa and [4-deoxy-Man-III]-GPI analogues
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A new [2 + 2 + 2] approach to construct GPI molecules through the efficient synthesis of glucosamine-inositol and tetramannose intermediates led to a total synthesis of a GPI-anchor of Trypanosoma cruzi, and also afforded a key intermediate for the synthe
- Ali, Asif,Gowda, D. Channe,Vishwakarma, Ram A.
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p. 519 - 521
(2008/09/18)
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- SYNTHETIC MOLECULES HAVING IMMUNE ACTIVITY
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The present invention is directed to synthetic molecules having biological activity similar to PIM (acyl glycerol phosphatidylinositol manno-oligosaccharide) activity, for use in the treatment and prevention of inflammatory or immune cell mediated diseases or disorders.
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Page/Page column 36; 48
(2010/02/12)
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- A study of polymer-supported bases for the solution phase synthesis of glycosyl trichloroacetimidates
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Polystyrene-supported strong organic bases are highly efficient reagents for the solution-phase synthesis of glycosyl trichloroacetimidates, affording quantitative yields of pure products in short reaction times after simple filtration and evaporation. Al
- Chiara, Jose Luis,Encinas, Lourdes,Díaz, Beatriz
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p. 2445 - 2448
(2007/10/03)
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- Tramadol analogs and uses thereof
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Compounds of formula I are effective in treating disorders modulated by opiate receptor activity and/or monoamine activity. In formula I, R1 is selected from alkyl, aryl, alkylaryl, substituted alkyl, substituted aryl, and substituted alkylaryl; R2 is selected from hydrogen, hydroxy, cyano, haloalkyl, glycosyl, SO2R5, and OR5; R3 and R4 are independently selected from hydrogen and lower alkyl, or R3 and R4 taken together with nitrogen form a five- or six-membered heterocyclic or substituted heterocyclic ring; and R5 is selected from alkyl, aryl, alkylaryl, substituted alkyl, substituted aryl, and substituted alkylaryl.
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- A novel synthesis of α-D-Galp-(1→3)-β-D-Galp-1-Ο-(CH2) 3-NH2, its linkage to activated matrices and absorption of anti-αGal xenoantibodies by affinity columns
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Pig organs transplanted into primates are rapidly rejected because of the interaction between Galα(1→3)Gal epitopes carried by the graft and natural antibodies (anti-αGal antibodies) present in the blood of the recipient. This report describes a simplified synthesis of the xenogeneic disaccharide and its linkage to activated gel matrices. The digalactosides α-D-Galp-(1→3)-α,β-D-Galp-Galp were synthesized by the condensation of the trichloroacetimidoyl 2,3,4,6-tetra-Ο-benzyl-β-D-galactopyranoside donor with the 3,4-unprotected allyl 2,6-di-Ο-benzyl-α- or β-D-galactopyranoside acceptor precursor. Deallylation and hydrogenolysis led to the free digalactoside, whereas hydrogenolysis alone resulted in the 1-Ο-propyl digalactoside. Both products were tested by inhibition ELISA of natural anti-Gala(1→3)Gal antibodies. The α-D-Galp-(1→3)-β-D-Galp-OPr was found to be the best inhibitor. Thus, the allyl group of the partially benzylated α-D-Galp-(1→3)-β-D-Galp-OAll was engineered, via the hydroxy-, the tosyloxy- and the azidopropyl intermediates, into an aminopropyl group amenable to binding to N-hydroxysuccinimide-activated agarose gel matrices in order to obtain specific immunoabsorption columns. Columns made of gel substituted with 5 μmol of disaccharide per milliliter were found efficient for the immunoabsorption of anti-αGal antibodies from human plasma.
- Liaigre, Jér?me,Dubreuil, Didier,Pradère, Jean-Paul,Bouhours, Jean-Fran?ois
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p. 265 - 277
(2007/10/03)
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- Design and use of an oxazolidine silyl enol ether as a new homoalanine carbanion equivalent for the synthesis of carbon-linked isosteres of O- glycosyl serine and N-glycosyl asparagine
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A trimethylsilyl enol ether carrying the N-Boc 2,2-dimethyloxazolidine ring was designed to serve as a synthetic equivalent of the homoalanine carbanion for the introduction of the α-amino acid side chain at the anomeric carbon of sugars. This new functio
- Dondoni, Alessandro,Marra, Alberto,Massi, Alessandro
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p. 933 - 944
(2007/10/03)
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- A general approach to 1,2-trans-C-glycosides via glycosyl samarium(III) compounds
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The samarium diiodide reduction of glycosyl pyridyl sulfones with ketones or aldehydes under Barbier conditions leads to the instantaneous and stereospecific formation of 1,2trans-C-glycosides in good to acceptable yields. Mannosyl pyridyl sulfones 5ac,h
- Skrydstrup, Troels,Jarreton, Olivier,Mazéas, Daniel,Urban, Dominique,Beau, Jean-Marie
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p. 655 - 671
(2007/10/03)
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- Linking carbohydrates to proteins using N-(2,2-dimethoxyethyl)-6- hydroxy hexanamide
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The title dimethyl acetal 4 and related compounds can be efficiently synthesized by treatment of 6-caprolactone with commercially available dialkyl acetals. Conventional glucosylation using 4 as a glycosyl acceptor gave mainly β-glycosides which were depr
- Zhang, Jian,Yergey, Alfred,Kowalak, Jeffrey,Kovac, Pavol
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p. 11783 - 11792
(2007/10/03)
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- Synthesis of a tetra-and a hexasaccharide donor corresponding to the non-reducing termini of mycobacterial 3-O-methylmannose polysaccharide (MMP)
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The blockwise synthesis of the title compounds, namely the tetra-and the hexasaccharide trichloroacetimidates (20) and (23), is described. Both acetates and imidates were employed as glycosyl donors in most of the coupling reactions. As nearly all of the
- Liao, Wensheng,Lu, Depei,Li, Aihong,Kong, Fanzuo
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p. 877 - 890
(2007/10/03)
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- A simple access to trichloroacetimidates
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O - Trichloroacetimidates can be prepared, under mild conditions in high yield and high purity, by reacting the substrate with trichloroacetonitrile in dichloromethane and 50% aqueous potassium hydroxide mixture containing a catalytic amount of tetra-n-butylammonium hydrogen sulfate.
- Patil, Vijay J.
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p. 1481 - 1484
(2007/10/03)
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- PREPARATION, ISOLATION AND CHARACTERIZATION OF POSITIONAL ISOMERS OF TRIGLUCOPYRANOSYLCYCLOMALTOHEPTAOSE
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The positional isomers of triglucopyranosyl-cyclomaltoheptaose (β-cyclodextrin, βCD) were chemically synthesized by glucosylation of tris(2,3-di-O-acetyl)-tetrakis(2,3,6-tri-O-acetyl)-βCDs with 2,3,4,6-tetra-O-benzyl-1-O-trichloroacetoimidoyl-α-D-glucopyr
- Nakanishi, Noriko,Nagafuchi, Yoshiko,Koizumi, Kyoko
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p. 981 - 990
(2007/10/02)
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- PISCICIDAL STEROL ACYLGLUCOSIDES FROM EDGEWORTHIA CHRYSANTA
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New potent piscicidal sterol acylglucosides named chrysanthosides have been obtained from the flower of Edgeworthia chrysantha, together with the previously known bis-coumarin and grasshopper ketone and their structures characterized to be sitosterol-3-O-6-linoleoyl- and sitosterol-3-O-6-linolenoyl-β-D-glucopyranosides by spectral data and synthesis.The natural and synthetic chrysanthosides possess potent piscicidal activity against killie-fish which was killed within 3 hr at a concentration of 0.1 ppm. Keywords: Edgeworthia chrysantha; Thymaaelaeaceae; flower; sitosterol-3-O-6-linoleoyl- and sitosterol-3-O-6-linolenoyl-β-D-glucopyranoside; grashopper ketone; daphnoretin; piscicidal activity; synthesis of chrysanthoside
- Hashimoto, Toshihiro,Tori, Motoo,Asakawa, Yoshinori
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p. 2927 - 2931
(2007/10/02)
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- Cardiac Glycosides. 7. Sugar Stereochemistry and Cardiac Glycoside Activity
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Digitoxigenin α-L, β-L, α-D, and β-D-glucosides; α-L-, β-L-, α-D-, and β-D-mannosides; and α-L- and β-L-rhamnosides were stereoselectively synthetized from the corresponding sugar tetrabenzyl trichloroacetimidates.The Na+, K+-ATPase receptor inhibitory activities of these glycosides (as a measure of receptor binding) were compared with those digitoxigenin, digitoxigenin 6'-hydroxy-β-D-digitoxide, digitoxigenin β-D-galactoside, and digitoxigenin β-D-digitoxoside.The observed activities reveal that a given sugar substituent may have a role in bindingof some glycoside stereoisomers, but not others.With α-L- and possibly β-L-rhamnosides, the 5'-CH3 and 4'-OH appear to have a predominant role in binding to the N+, K+-ATPase receptor.Addition of a 6'-OH to form the corresponding mannosides dramatically disrupts the effect of both the 5'-CH3 and 4'-OH in prompting receptor binding of the α-L isomer.However, with the β-L isomer, some influence of 4'-OH, 3'-OH, and 2'-OH binding remains.With β-D-glycosides, binding via the "5'-CH3 site" appears to be of little importance and addition of a 6'-OH diminishes activity only slightly.With these β-D-glycosides, and equatorial 4'-OH, axial 3'-OH, and equatorial 2'-OH groups appear to contribute to binding.
- Rathore, Hargovind,From, Arthur H. L.,Ahmed, Khalil,Fullerton, Dwight S.
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p. 1945 - 1952
(2007/10/02)
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- CARDIAC GLYCOSIDES: 5. STEREOSELECTIVE SYNTHESES OF DIGITOXIGENIN α-D, β-D, α-L AND β-L-GLUCOSIDES
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As part of a continuing study of cardiac glycosides, stereoselective syntheses of the four possible glucosides of digitoxigenin were developed via the thermodynamically produced tetra-O-benzyl-D- and L-glucosyl α-trichloroacetaimidates 2α and 11α, and the
- Rathore, Hargovind,Hashimoto, Toshihiro,Igarashi, Kikuo,Nukaya, Haruo,Fullerton, Dwight S.
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p. 5427 - 5438
(2007/10/02)
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- Glycosyl Imidates, 12. - Direct Synthesis of O-α- and O-β-Glycosyl Imidates
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1-O-Unsubstituted aldoses afford with halogen-activated nitriles under base catalysis directly O-α- and O-β-glycosyl imidates which can be isolated as stable compounds.Investigations with 2,3,4,6-tetra-O-benzyl- and -acetylglucose (1a, b), trichloroacetonitrile and trifluoroacetonitrile and NaH and K2CO3, respectively, as base have demonstrated, that the β-glucopyranosyl-1-oxido oxygen atom is more nucleophilic (rapid formation of 3a-β, 3b-β, 4a-β, and 4b-β) than the α-glycopyranosyl-1-oxido oxygen atom.Because of the reversibility of these reactions, however,due to the anomeric effect finally the thermodynamically more stable α-imidates 3a-α, 3b-α, 4a-α, and 4b-α are formed exclusively.Therefore O-α- and O-β-glycosyl imidate formation can be conducted highly diastereoselectively. - From trichloroacetonitrile and other 1-O-unsubstituted carbohydrates the imidates 7-α - 13-β were obtained as stable compounds. - Less activated nitriles (chloroacetonitrile, dichloroacetonitrile) have proven not or not so successful in the direct O-glycosyl imidate formation. - N-Aryl ketenimines yielded cleanly base-catalyzed direct O-glycosyl imidate formation.However, because of the irreversibility of this reaction under the reaction conditions only kinetic product formation was observed (leading to the β-imidates 14a-β - 14d-β and 15d-β.Similarly 1-O-unprotected mannose gave only the β-product 16d-β.
- Schmidt, Richard R.,Michel, Josef,Roos, Michael
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p. 1343 - 1357
(2007/10/02)
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