- Chemical synthesis and pharmacological properties of heparin pentasaccharide analogues
-
The pentasaccharide fondaparinux is a synthetic anticoagulant based on heparin antithrombin-binding sequence. Fondaparinux improves safety and predictable pharmacodynamics compared with heparins; however, it requires a complicate synthesis process which contain more than 50 steps of synthesis. Herein, we designed and synthesized four fondaparinux analogues (compounds 1, 2, 3, 4) using a [2+3] convergent synthetic method, which greatly simplified the synthetic process, improved the product yield, and curtailed the expenditures. These synthesized compounds showed stronger anticoagulant activities by factor Xa inhibition (IC50 725–1126 nM vs. 1909 nM for fondaparinux) in the AT-dependent manner. After subcutaneous (s.c.) administration to rats, the compounds displayed long-lasting anti-factor Xa activities and inhibition of thrombin generation ex vivo. Compared with fondaparinux, these compounds were slowly eliminated after s.c. administration to rats, the half-lies (t1/2) were more than 2-fold of that of fondaparinux. These results suggested the pentasaccharide analogues may exhibit better pharmacokinetic and predictable pharmacodynamic characteristics.
- Luo, Lan,Wu, Jian,Wu, Mingyi,Wu, Xin,Xu, Dan,Zhang, Linlin,Zhou, Zhipeng
-
-
- Serendipitous one-pot synthesis of chiral dienes from pyranosidic 2,4-bistriflates
-
Attempted nucleophilic displacements of L-rhamnosyl 2,4-bistriflates led to serendipitous formation of a chiral diene via competing cascade eliminations. The reaction also followed the same pathway with D-rhamnosyl and D-mannosyl 2,4-bistriflates substrat
- Rai, Diksha,Sanapala, Someswara Rao,Kulkarni, Suvarn S.
-
-
- Chemoenzymatic Synthesis of Sialosides Containing 7- N- or 7,9-Di- N-acetyl Sialic Acid as Stable O-Acetyl Analogues for Probing Sialic Acid-Binding Proteins
-
A novel chemoenzymatic synthon strategy has been developed to construct a comprehensive library of α2-3- and α2-6-linked sialosides containing 7-N- or 7,9-di-N-acetyl sialic acid, the stable analogue of naturally occurring 7-O-acetyl- or 7,9-di-O-acetyl-s
- Chen, Xi,Diaz, Sandra,Kooner, Anoopjit Singh,Santra, Abhishek,Varki, Ajit,Yu, Hai
-
p. 14381 - 14397
(2021/11/01)
-
- Solvent-Free Glycosylation from per-O-Acylated Donors Catalyzed by Methanesulfonic Acid
-
The huge importance of carbohydrates and their derivatives in biomedical and industrial applications call for the development of streamlined and sustainable procedures for their synthetic elaboration. Here reported a novel glycosylation method based on direct activation of readily available per-O-acylated (acetylated or benzoylated) donors, promoted under air by methanesulfonic acid as a cheap and green catalyst in the absence of any solvent. Besides the beneficial avoidance of toxic and polluting organic solvents, these conditions were found critical for activating such poorly reactive donors with a very small catalyst loading (only 5 mol %), instead of stoichiometric Lewis acid promoters typically employed. Desired glycosides were quickly obtained, in most cases with high 1,2-trans stereoselectivity. Other main advantages over reported glycosylations with similar donors are the limited stoichiometric excess of the acceptor (or the donor), the easy applicability and low cost of the procedure and the wide target scope, also covering the synthesis of disaccharides and other non-trivial glycosides with applicable potential.
- Bedini, Emiliano,Iadonisi, Alfonso,Silipo, Alba,Traboni, Serena,Vessella, Giulia
-
p. 5669 - 5676
(2021/11/11)
-
- Synthesis of nature product kinsenoside analogues with anti-inflammatory activity
-
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
-
-
- Studies towards the total synthesis of repeating unit of O-sulfated polysaccharide from marine bacterium Cobetia pacifica KMM 3878
-
Herein we report assembly of the appropriately protected trisaccharide repeating unit of Cobetia pacifica KMM 3878 O-sulfated polysaccharide. Our synthesis involves 3,4-O-pyruvilated galactose as the key building block which acts as a donor as well as acceptor in the construction of trisaccharide. We obtained the R isomer as a major stereoisomer in the pyruvilation reaction. The glycosylations proceeded with high stereo and regioselectivity.
- Pradhan, Kabita,Podilapu, Ananda Rao,Kulkarni, Suvarn S.
-
p. 255 - 264
(2020/03/18)
-
- Tea leaf perfumery precursor glucoside and synthesizing method thereof
-
The invention relates to a tea leaf perfumery precursor glucoside and a synthesizing method thereof. The synthesizing method comprises the following steps of synthesizing ten glucosides including aromatic alcohol ( alkanol )-beta -D-glucosides and aromatic alcohol (alkanol )-beta -D-primrose indicans. The synthesizing method disclosed by the invention is a glucoside synthesizing method which is good in selectivity, high in production rate and low in cost.
- -
-
Paragraph 0067-0068; 0071-0072; 0082-0083
(2020/07/02)
-
- Method for chemically synthesizing beta-arbutin
-
The invention provides a method for chemically synthesizing beta-arbutin. The synthesis method includes the following steps: using D-glucose and acetic anhydride as raw materials, and carrying out reaction under the catalysis of molecular iodine to obtain a penta-acetyl glucose anomer mixture; subjecting the mixture without isolation and 4-Methoxyphenol to reaction under the catalysis of boron trifluoride diethyl etherate to obtain 4-Methoxyphenyl-2,3,4,6-Tetra-O-acetyl-beta-D-glucopyanoside, dissolving the 4-Methoxyphenyl-2,3,4,6-Tetra-O-acetyl-beta-D-glucopyanoside in anhydrous methanol, andremoving the acetyl group on the sugar ring and the methoxy group on the benzene ring under the conditions of sodium methoxide and cuprous oxide, thereby obtaining beta-arbutin. The method has the advantages of convenient operation, less discharge of the three wastes (waste gas, waste water and industrial residue), high yield and low cost, and the method is suitable for industrial production.
- -
-
Paragraph 0004; 0005; 0007; 0009
(2020/02/10)
-
- Synthesis method of core structure of O-mannan
-
The invention belongs to the field of synthesis of saccharide substances, and particularly relates to a synthesis method of the core structure of O-mannan. Conventional research indicates that alpha-DG O-mannan is relevant with a mechanism of diseases of
- -
-
Paragraph 0104; 0114; 0116
(2019/08/06)
-
- Copper-mediated O-arylation of lactols with aryl boronic acids
-
An efficient and novel methodology to access phenolic glycosides has been established by using copper-mediated coupling reaction of aryl boronic acids with hemiacetals. The reaction takes place normally in the presence of Cu(OAc)2 (1.0 equiv.) and pyridine (2.0 equiv.) at 40 °C. This protocol distinguishes itself by wide substrate scope, operational simplicity and giving rise to a myriad of phenolic glycosides in good to excellent yields.
- Sui, Jing-Jing,Xiong, De-Cai,Ye, Xin-Shan
-
supporting information
p. 1533 - 1537
(2019/06/21)
-
- Regio/Stereoselective Glycosylation of Diol and Polyol Acceptors in Efficient Synthesis of Neu5Ac-α-2,3-LacNPhth Trisaccharide
-
A concise approach to a Neu5Ac-α-2,3-LacNPhth trisaccharide derivative was developed. First, the regio/stereoselective glycosylation between glycoside donors and glucoNPhth diol acceptors was investigated. It was found that the regioselectivity depends not only on the steric hindrance of the C2-NPhth group and the C6-OH protecting group of the glucosamine acceptors, but also on the leaving group and protecting group of the glycoside donors. Under optimized conditions, LacNPhth derivatives were synthesized in up to 92 % yield through a regio/stereoselective glycosylation between peracetylated-α-galactopyranosyl trichloroacetimidate and p-methoxyphenyl 6-O-tert-butyldiphenylsilyl-2-deoxy-2-phthalimido-β-d-glucopyranoside, avoiding the formation of glycosylated orthoesters and anomeric aglycon transfer. Then, the LacNPhth derivative was deacylated and then protected on the primary position by TBDPS to form a LacNPhth polyol acceptor. Finally, the Neu5Ac-α-2,3-LacNPhth derivative was synthesized in 48 % yield through the regio/stereoselective glycosylation between the LacNPhth polyol acceptor and a sialyl phosphite donor. Starting from d-glucosamine hydrochloride, the target Neu5Ac-α-2,3-LacNPhth derivative was synthesized in a total yield of 18.5 % over only 10 steps.
- Zhang, Ying,Zhao, Fu-Long,Luo, Tao,Pei, Zhichao,Dong, Hai
-
p. 223 - 234
(2018/12/05)
-
- Copper-Catalyzed Anomeric O-Arylation of Carbohydrate Derivatives at Room Temperature
-
Direct and practical anomeric O-arylation of sugar lactols with substituted arylboronic acids has been established. Using copper catalysis at room temperature under an air atmosphere, the protocol proved to be general, and a variety of aryl O-glycosides have been prepared in good to excellent yields. Furthermore, this approach was extended successfully to unprotected carbohydrates, including α-mannose, and it was demonstrated here how the interaction between carbohydrates and boronic acids can be combined with copper catalysis to achieve selective anomeric O-arylation.
- Verdelet, Tristan,Benmahdjoub, Sara,Benmerad, Belkacem,Alami, Mouad,Messaoudi, Samir
-
p. 9226 - 9238
(2019/08/12)
-
- 4-Methyltetrahydropyran (4-MeTHP): Application as an Organic Reaction Solvent
-
4-Methyltetrahydropyran (4-MeTHP) is a hydrophobic cyclic ether with potential for industrial applications. We herein report, for the first time, a comprehensive study on the performance of 4-MeTHP as an organic reaction solvent. Its broad application to organic reactions includes radical, Grignard, Wittig, organometallic, halogen-metal exchange, reduction, oxidation, epoxidation, amidation, esterification, metathesis, and other miscellaneous organic reactions. This breadth suggests 4-MeTHP can serve as a substitute for conventional ethers and harmful halogenated solvents. However, 4-MeTHP was found incompatible with strong Lewis acids, and the C?O bond was readily cleaved by treatment with BBr3. Moreover, the radical-based degradation pathways of 4-MeTHP, THP and 2-MeTHF were elucidated on the basis of GC-MS analyses. The data reported herein is anticipated to be useful for a broad range of synthetic chemists, especially industrial process chemists, when selecting the reaction solvent with green chemistry perspectives.
- Kobayashi, Shoji,Tamura, Tomoki,Yoshimoto, Saki,Kawakami, Takashi,Masuyama, Araki
-
p. 3921 - 3937
(2019/11/11)
-
- Selective acetolysis of primary benzyl groups in carbohydrate derivatives under the mild reaction condition
-
Selective acetolysis of the primary benzyloxy groups in a wide variety of carbohydrate derivatives was achieved in excellent yield using acetic anhydride and perchloric acid supported over silica (HClO4–SiO2) as a solid acid catalyst
- Kundu, Monalisa,Misra, Anup Kumar
-
-
- KinITC—One Method Supports both Thermodynamic and Kinetic SARs as Exemplified on FimH Antagonists
-
Affinity data, such as dissociation constants (KD) or inhibitory concentrations (IC50), are widely used in drug discovery. However, these parameters describe an equilibrium state, which is often not established in vivo due to pharmacokinetic effects and they are therefore not necessarily sufficient for evaluating drug efficacy. More accurate indicators for pharmacological activity are the kinetics of binding processes, as they shed light on the rate of formation of protein–ligand complexes and their half-life. Nonetheless, although highly desirable for medicinal chemistry programs, studies on structure–kinetic relationships (SKR) are still rare. With the recently introduced analytical tool kinITC this situation may change, since not only thermodynamic but also kinetic information of the binding process can be deduced from isothermal titration calorimetry (ITC) experiments. Using kinITC, ITC data of 29 mannosides binding to the bacterial adhesin FimH were re-analyzed to make their binding kinetics accessible. To validate these kinetic data, surface plasmon resonance (SPR) experiments were conducted. The kinetic analysis by kinITC revealed that the nanomolar affinities of the FimH antagonists arise from both (i) an optimized interaction between protein and ligand in the bound state (reduced off-rate constant koff) and (ii) a stabilization of the transition state or a destabilization of the unbound state (increased on-rate constant kon). Based on congeneric ligand modifications and structural input from co-crystal structures, a strong relationship between the formed hydrogen-bond network and koff could be concluded, whereas electrostatic interactions and conformational restrictions upon binding were found to have mainly an impact on kon.
- Zihlmann, Pascal,Silbermann, Marleen,Sharpe, Timothy,Jiang, Xiaohua,Mühlethaler, Tobias,Jakob, Roman P.,Rabbani, Said,Sager, Christoph P.,Frei, Priska,Pang, Lijuan,Maier, Timm,Ernst, Beat
-
supporting information
p. 13049 - 13057
(2018/08/17)
-
- Total Synthesis of the Diglycosidic Tetramic Acid Ancorinoside A
-
Ancorinoside A, a metabolite of a sponge Ancorina sp., was prepared in 18 steps as the first derivative of this class of glycosylated 3-acyltetramic acids. It features a β-d-glucopyranosyl-(1→4)-β-d-galacturonic acid linked to a d-aspartic acid derived te
- Petermichl, Markus,Schobert, Rainer
-
supporting information
p. 14743 - 14746
(2017/10/27)
-
- Phosphoryl mannopentaose and derivatives thereof, and preparation methods and application thereof
-
The invention provides phosphoryl mannopentaose as shown in a formula (I) and derivatives as shown in formula (II) to (XI) of phosphoryl mannopentaose, and preparation methods thereof. According to the preparation methods, reactivity is regulated and cont
- -
-
Paragraph 0243; 0244
(2017/06/02)
-
- Stereocontrolled Synthesis of Phenolic α-d-Glycopyranosides
-
Adopting the ‘remote activation concept’ toward stereocontrolled glycoside synthesis with minimal use of protection groups, a general synthesis of phenolic 1,2-cis glycopyranosides is reported, as exemplified by aryl α-d-galacto-, α-d-gluco- and 2-azido α-d-glucopyranosides among others using glycosyl donors bearing an anomeric (3-bromo-2-pyridyloxy) group and catalyzed by methyl triflate.
- St-Pierre, Gabrielle,Dafik, Laila,Klegraf, Ellen,Hanessian, Stephen
-
p. 3575 - 3588
(2016/10/17)
-
- Solution and Solid-Phase Stereocontrolled Synthesis of 1,2-cis-Glycopyranosides with Minimally Protected Glycopyranosyl Donors Catalyzed by BF3-N,N-Dimethylformamide Complex
-
Methods are described for the stereoselective synthesis of 1,2-cis glycopyranosides in the d-galacto, d-gluco, and 2-azido-2-deoxy-d-glucopyranoside series utilizing minimally protected (3-bromo-2-pyridyloxy) β-d-glycopyranosyl donors in the presence of BF3-N,N-dimethylformamide (DMF) as a catalyst and a variety of alcohol acceptors relying on the "remote activation concept". Precursors to antifreeze glycopeptide components are synthesized in excellent yields and high α/β ratios. The method is adaptable to one-pot sequential glycosidation as well as to solid-supported synthesis giving access to diverse sets of minimally protected α-d-glycopyranosides as major products.
- St-Pierre, Gabrielle,Hanessian, Stephen
-
supporting information
p. 3106 - 3109
(2016/07/14)
-
- SGLT-2 INHIBITORS
-
Provided are compounds of SGLT-2 inhibitors, pharmaceutically acceptable salts, hydrides and stereoisomers thereof. The compounds are employed in pharmaceutical compositions, and methods of making and use, including treating a person in need thereof with
- -
-
Paragraph 0159; 0160
(2016/04/09)
-
- HUMAN iNKT CELL ACTIVATION USING GLYCOLIPIDS
-
Glycosphingolipids (GSLs) compositions and methods for iNKT-independent induction of chemokines are disclosed.
- -
-
Paragraph 0268
(2016/05/10)
-
- Facile synthesis of the pentasaccharide repeating unit of the exopolysaccharide from Cryptococcus neoformans serotype D
-
Abstract β-D-GlcpA-(1→2)-[β-D-Xylp-(1→2)-α-D-Manp-(1→3)]-α-D-Manp-(1→3)-α-D-Manp, the repeating unit of the exopolysaccharide from Cryptococcus neoformans serotype D, was synthesized as its 4-methoxyphenyl glycoside. The approach presented here also provi
- Zhuo, Xiao-Bin,Zou, Yan,Huang, Sheng-Jun,Liao, Jun,Hu, Hong-Gang,Zhao, Qing-Jie,Wu, Qiu-Ye
-
p. 618 - 626
(2015/06/02)
-
- HUMAN iNKT CELL ACTIVATION USING GLYCOLIPIDS WITH ALTERED GLYCOSYL GROUPS
-
Glycosphingolipids (GSLs) bearing α-glucose (α-Glc) that preferentially stimulate human invariant NKT (iNKT) cells are provided. GSLs with α-glucose (α-Glc) that exhibit stronger induction in humans (but weaker in mice) of cytokines and chemokines and exp
- -
-
Paragraph 0288-0290; 0314
(2015/03/16)
-
- Identification of living legionella pneumophila using species-specific metabolic lipopolysaccharide labeling
-
Legionella pneumophila is a pathogenic bacterium involved in regular outbreaks characterized by a relatively high fatality rate and an important societal impact. Frequent monitoring of the presence of this bacterium in environmental water samples is neces
- Pons, Jordi Mas,Dumont, Audrey,Sautejeau, Gregory,Fugier, Emilie,Baron, Aurelie,Dukan,Vauzeilles, Boris
-
supporting information
p. 1275 - 1278
(2014/03/21)
-
- Tuning the moenomycin pharmacophore to enable discovery of bacterial cell wall synthesis inhibitors
-
New antibiotic drugs need to be identified to address rapidly developing resistance of bacterial pathogens to common antibiotics. The natural antibiotic moenomycin A is the prototype for compounds that bind to bacterial peptidoglycan glycosyltransferases
- Gampe, Christian M.,Tsukamoto, Hirokazu,Doud, Emma H.,Walker, Suzanne,Kahne, Daniel
-
p. 3776 - 3779
(2013/04/23)
-
- A divergent approach to the synthesis of simplexides and congeners via a late-stage olefin cross-metathesis reaction
-
Simplexides constitute a unique group of immunosuppressive glycolipids that demonstrate antiproliferative activities against activated T-cell lymphocytes via a unique non-cytotoxic inhibition. To investigate the structure-activity relationship of the varied long-chain secondary alcohols on simplexides, we developed an efficient and divergent route to the synthesis of simplexides and congeners, taking advantage of a late-stage olefin cross-metathesis reaction.
- Li, Jiakun,Li, Wei,Yu, Biao
-
supporting information
p. 4971 - 4974
(2013/08/23)
-
- Synthesis and immunological characterization of modified hyaluronic acid hexasaccharide conjugates
-
The synthesis of a tetanus toxoid (TT)-conjugate of a hyaluronic acid (HA) hexasaccharide is described. The compound was intended for use in monitoring HA levels as a disease marker and as a potential vaccine against Group A Streptococcus (GAS) infections. We also report the synthesis of a chemically modified HA-hexasaccharide-TT conjugate in which the N-acetyl moiety of the N-acetyl-d-glucosamine residue is replaced with an N-propionyl unit in order to enhance immunogenicity. The oligosaccharides are synthesized in a convergent manner. The TT-conjugate syntheses rely on the reaction of the amines on the 6-aminohexyl aglycon of the hexasaccharides with diethyl squarate to give the monoethyl squarate adducts. Subsequent reactions with lysine ε-amino groups on TT then give the glycoconjugates containing an average of 8 hexasaccharide haptens per TT molecule. Immunological studies in mice show very similar antibody responses with both conjugates, suggesting that the N-acetyl groups of the glucosaminyl residues of the HA-hexasaccharide are not a critical part of the epitope recognized by the anti-HA polyclonal immune response. Furthermore, it would appear that the N-acyl moieties are not in close contact with the amino acid residues of the antibody combining sites.
- Gu, Guofeng,Adabala, Pal John Pal,Szczepina, Monica G.,Borrelli, Silvia,Pinto, B. Mario
-
p. 8004 - 8019
(2013/09/12)
-
- COMPOUNDS AND METHODS FOR CHEMICAL AND CHEMO-ENZYMATIC SYNTHESIS OF COMPLEX GLYCANS
-
The present invention provides chemical and chemo-enzymatic methods for the synthesis of a wide array of complex asymmetric multi-antennary glycans.
- -
-
Page/Page column 44
(2012/10/18)
-
- Revisit of the phenol O-glycosylation with glycosyl imidates, BF 3·OEt2 is a better catalyst than TMSOTf
-
With BF3·OEt2 as the catalyst, the glycosylation of phenols with glycosyl trichloroacetimidates (or N-phenyl trifluoroacetimidates) bearing 2-O-participating groups leads to the desired 1,2-trans-O-glycosides in generally excellent yields without formation of the 1,2-cis-anomers. However, with TMSOTf as the catalyst, the outcomes of the corresponding phenol O-glycosylation are highly dependent on the nucleophilicity of the phenols; less nucleophilic is the phenol, higher amounts of the 1,2-cis-O-glycoside together with more side-products are generated. 1,2-Orthoesters have been found to be the major products at a low temperature (a higher temperature. BF 3·OEt2 is an effective catalyst to promote the conversion of 1,2-orthoesters into the corresponding 1,2-trans-O-glycosides. However, the 1,2-orthoesters could be converted into the dioxolenium triflate and glycosyl triflate in the presence of TMSOTf, these intermediates which might be in equilibrium with the glycosyl oxocarbenium related species lead to the final mixture of the α/β-O-glycosides and side-products.
- Li, Yali,Mo, Huaping,Lian, Gaoyan,Yu, Biao
-
-
- Application of silver N-heterocyclic carbene complexes in O-glycosidation reactions
-
We report the efficient O-glycosidation of glycosyl bromides with therapeutically relevant acceptors facilitated by silver N-heterocyclic carbene (Ag-NHC) complexes. A set of four Ag-NHC complexes was synthesized and evaluated as promoters for glycosidation reactions. Two new bis-Ag-NHC complexes derived from ionic liquids 1-benzyl-3-methyl-1H-imidazolium chloride and 1-(2-methoxyethyl)-3-methylimidazolium chloride were found to efficiently promote glycosidation, whereas known mono-Ag complexes of 1,3-bis(2,4,6- trimethylphenyl)imidazolium chloride and 1,3-bis(2,6-di-isopropylphenyl) imidazolium chloride failed to facilitate the reaction. The structures of the promoters were established by X-ray crystallography and these complexes were employed in the glycosidation of different glycosyl bromide donors with biologically valuable acceptors, such as estrone, estradiol, and various flavones. The products were obtained in yields considered good to excellent, and all reactions were highly selective for the β isomer regardless of neighboring group effects.
- Talisman, Ian J.,Kumar, Vineet,Deschamps, Jeffrey R.,Frisch, Mark,Malhotra, Sanjay V.
-
experimental part
p. 2337 - 2341
(2011/12/04)
-
- O-Glycosidation reactions promoted by in situ generated silver N-heterocyclic carbenes in ionic liquids
-
We herein report O-glycosidation reactions promoted via silver N-heterocyclic carbene complexes formed in situ in ionic liquids. Seven different room temperature ionic liquids were screened for the glycosidation reaction of 4-nitrophenol with tetra-O-acetyl-α-d-galactopyranosyl bromide. Good to excellent yields were obtained using Ag-NHC complexes derived from imidazolium halide salts to promote the glycosidation reaction, whereas yields considered moderate to low were obtained without use of the silver carbene complex. Anion metathesis of the ionic liquids with inexpensive alkylammonium halides also resulted in silver N-heterocyclic carbene formation and subsequent O-glycosidation in the presence of silver carbonate. Effective utility of this methodology has been demonstrated with biologically relevant acceptors (including flavones and steroids) where O-β-glycoside products were obtained selectively in moderate to good yields. We have also demonstrated that the Ag-NHC complex is a superior promoter to traditionally used silver carbonate for the glycosidation of polyphenolic acceptors. The ionic liquids used in the study could be recycled three times without apparent loss in activity.
- Talisman, Ian Jamie,Kumar, Vineet,Razzaghy, Jacqueline,Malhotra, Sanjay V.
-
experimental part
p. 883 - 890
(2011/06/20)
-
- Facile preparation of α-glycosyl iodides by in situ generated aluminum iodide: Straightforward synthesis of thio-, seleno-, and o-glycosides from unprotected reducing sugars
-
A facile and practical protocol was developed for the synthesis of glycosyl iodides using AlI3 generated in situ from cheap aluminum metal and molecular iodine. Furthermore, in combination with iodine-catalyzed per-O-acetylation, sequential synthesis of per-acetylated glycosyl iodides, per-acetylated thioglycosides, selenoglycoside, and O-glycosides from unprotected reducing sugars was also achieved with complete diastereocontrol in a one-pot version. Supplemental material is available for this article. Go to the publisher's online edition of Journal of Carbohydrate Chemistry to view the free supplemental file. Copyright Taylor & Francis Group, LLC.
- Weng, Shiue-Shien,Li, Chia-Ling,Liao, Chun-Sheng,Chen, Ting-An,Huang, Chao-Cheih,Hung, Kuo-Tung
-
experimental part
p. 429 - 440
(2012/06/01)
-
- Neighboring group participation in glycosylation reactions by 2,6-disubstituted 2-O-benzoyl groups: A mechanistic investigation
-
Variable yields and glycosylation stereoselectivity were obtained for NIS/TfOH-medi- ated reaction of 4-methoxyphenyl 2,4,6-tetra-O-acetyl-β-D- galactopyranoside and thiogalactosides bearing acetyl, benzoyl, 2,6-dimethoxylbenzoyl, 2,4,6-trimethylbenzoyl, or 2,6-dichlorobenzoyl groups at the 2-positions and acetyl at the remainder. X-ray structures of 4-methylphenyl 2,3,4,6-tetra-O-(2,4,6-trimethylbenzoyl)-1-thio-β-D-galactopyr anoside and 4-methylphenyl 3,4-O-isopropylidene-2,6-di-O-(2,4,6-trimethylbenzoyl)-1-thio- β-D-galactopyranoside revealed slightly distorted 4C1 chair conformations. Variable temperature NMR revealed that activation of 4-methylphenyl 2,3,4,6-tetra-O-(2,4,6-trimethylbenzoyl)-1-thio-β-D- galactopyranoside afforded only dioxolenium ion, whereas 4-methylphenyl 3,4,6-tri-O-acetyl-2-O-(2,4,6-trimethylbenzoyl)-1-thio-β-D- galactopyranoside gave a 1:1 mixture of dioxolenium ion and glycosyl triflate. However, the reaction intermediates formed from these deactivated donors do not influence the glycosylation stereoselectivity; instead, it is influenced by steric and electronic interactions at the transition states. Copyright Taylor & Francis Group, LLC.
- Williams, Rohan J.,McGill, Nathan W.,White, Jonathan M.,Williams, Spencer J.
-
p. 236 - 263
(2011/04/22)
-
- Bronsted acid-promoted glycosylations of disaccharide glycal substructures of the saccharomicins
-
An acid-promoted glycosylate and alkynol cycloisomerization sequence provided direct access to the 2-deoxytrisaccharide corresponding to the fucose-saccharosamine-digitoxose substructure of saccharomicin B. In the course of this work, the absolute stereochemistry of the repeating fucose- saccharosamine disaccharide of saccharomicins was also confirmed.
- Balthaser, Bradley R.,McDonald, Frank E.
-
supporting information; experimental part
p. 4850 - 4853
(2009/12/28)
-
- 2,6-Disubstituted benzoates as neighboring groups for enhanced diastereoselectivity in β-galactosylation reactions: Synthesis of β-1,3-linked oligogalactosides related to arabinogalactan proteins
-
(Chemical Equation Presented) Arabinogalactan proteins (AGPs) are plant glycoproteins which contain a β-1,3-linked galactan core. The synthesis of the β-galactopyranose-1,3-β-galactopyranose linkage using various 2-O-acyl-protected glycosyl donors has bee
- McGill, Nathan W.,Williams, Spencer J.
-
experimental part
p. 9388 - 9398
(2010/03/04)
-
- MOENOMYCIN ANALOGS, METHODS OF SYNTHESIS, AND USES THEREOF
-
The present invention provides novel moenomycin analogs as well as pharmaceutical compositions thereof, methods of synthesis, and methods of use in treating an infection by administering an inventive compound to a subject in need thereof. The moenomycin a
- -
-
-
- CARBOHYDRATE BASED TOLL-LIKE RECEPTOR (TLR) ANTAGONISTS
-
The invention provides carbohydrate based compounds, methods of preparation, and compositions useful for modulating signaling through Toll-like receptors. The methods involve contacting a TLR-expressing cell with a carbohydrate based compound of the inven
- -
-
Page/Page column 18-19
(2009/09/07)
-
- A Chemoenzymatic route to conjugatable β(1→3)-Glucan Oligosaccharides
-
3II-O-Allyl-α laminaribiosyl fluoride was prepared as a key synthon for the enzymatic synthesis of β(1→3)-glucan oligosaccharides, catalyzed by a mutated β(1→3)-glucanase (E231G) from barley (Hordeum vulgare L.). A strategy was developed for en
- Montel, Emilie,Hrmova, Maria,Fincher, Geoffrey B.,Driguez, Hugues,Cottaz, Sylvain
-
experimental part
p. 575 - 584
(2010/01/16)
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- Samarium trifluoromethanesulfonate: An efficient moisture tolerant acylation catalyst under solvent-free condition
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Samarium trifluoromethanesulfonate catalyzed the acylation of phenols, alcohols, thiols, free reducing sugars, and glycosides in excellent yields at ambient temperature under solvent-free condition using stoichiometric amounts of various anhydrides. (Chemical Equation Presented). Copyright Taylor & Francis Group, LLC.
- Roy, Bimalendu,Dasgupta, Somnath,Kumar Rajput, Vishal,Mukhopadhyay, Balaram
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- Synergistic solvent effect in 1,2-cis-glycoside formation
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Construction of three continuous 1,2-cis-α-glucosidic linkages was achieved in optimized solvent system. High-throughput optimization was conducted, by using substrates protected by perdeuterated benzyl (Bn-d7) groups. It enabled facile evaluat
- Ishiwata, Akihiro,Munemura, Yuichi,Ito, Yukishige
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- Solvent-free mechanochemical synthesis of aryl glycosides
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Aryl glycosides have been prepared from a range of readily available glycosyl halides by a solvent-free mechanochemical procedure employing a planetary ball mill in excellent yields. Besides being a solvent-free reaction, the procedure has been successful in eliminating the need for employing any phase-transfer catalyst in the reaction. Copyright Taylor & Francis Group, LLC.
- Patil, Premanand Ramrao,Ravindranathan Kartha
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experimental part
p. 411 - 419
(2009/04/11)
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- Lanthanum trifluoromethane-sulfonate-catalyzed facile synthesis of per-O-acetylated sugars and their one-pot conversion to S-aryl and O-alkyl/aryl glycosides
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Lanthanum trifluoromethanesulfonate-catalyzed solvent-free per-O-acetylation with stoichiometric acetic anhydride proceeds in high yield (95%-99%) to afford exclusively pyranose products as anomeric mixtures. Subsequent anomeric substitution employing borontrifluoride etherate and thiols or alcohols furnished the corresponding 1,2-trans-linked thioglycosides and O-glycosides, respectively, in good to excellent overall yield (75%-85%). Alternatively, reaction of free sugars in neat alcohol employing the same catalyst at elevated temperature gives the corresponding 1,2-cis-linked O-glycosides (along with 1,2-trans-linked glycosides as minor product) in good yield (73%-80%). Anomeric mixtures of compounds thus produced were characterized as their per-O-acetylated derivatives.
- Dasgupta, Somnath,Rajput, Vishal Kumar,Roy, Bimalendu,Mukhopadhyay, Balaram
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- Stereoselective single-step synthesis and X-ray crystallographic investigation of acetylated aryl 1,2-trans glycopyranosides and aryl 1,2-cis C2-hydroxy-glycopyranosides
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Reported is an attractive and environmentally friendly method for the synthesis of the title compounds in moderate yield using inexpensive 1,2,3,4,6-penta-O-acetyl-β-d-gluco- and galactopyranoses as sugar donors, five different phenols as acceptors and H-β zeolite as the catalyst. The yield (23-28%) of aryl 3,4,6-tri-O-acetyl-α-d-glycopyranosides obtained in this single-step procedure is considerably higher than that obtained using previously reported methods. Treatment of an orthoacetate, 3,4,6-tri-O-acetyl- [1,2-O-(1-p-fluorophenoxyethylidene)]-α-d-glucopyranose, with p-fluorophenol under the same solvent-free reaction conditions also led to the formation of the title compounds in similar yield and composition. X-ray crystallographic analysis of phenyl 3,4,6-tri-O-acetyl-α-d-glucopyranoside and p-fluorophenyl 3,4,6-tri-O-acetyl-α-d-glucopyranoside showed that the molecular packing is stabilized by C-H...O, C-H...π and C-H...F interactions, in addition to regular hydrogen bonding patterns.
- Aich, Udayanath,Loganathan, Duraikkannu
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- High throughput screening of O-glycosylation conditions
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We report a novel methodology for rapid and quantitative screening of O-glycosylation reactions of application to the analysis of parallel reaction systems. Our system exploits perdeuterated benzyl (Bn-d7) ether, and stereoselectivity and yield
- Ishiwata, Akihiro,Ito, Yukishige
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p. 3521 - 3524
(2007/10/03)
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- Efficient synthesis of two HNK-1 related pentasaccharides
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Two pentasaccharides, representative of those found on complex N-glycans, were synthesized for use as potential substrates for sulfotransferases. The synthesis was achieved by the addition of a disaccharide donor β-D-GlcA(1→3)α-D-Gal-trichloroacetimidate
- Belot, Frederic,Otter, Albin,Fukuda, Minoru,Hindsgaul, Ole
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p. 1315 - 1318
(2007/10/03)
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- Stereoselectivity of reactions at the glycoside center of carbohydrates: VII. Synthesis of aryl α- and -β-D-glucopyranosides by Helferich, catalyzed by boron trifluoride etherate
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13C NMR spectroscopy was used to study the stereoselectivity of glycosylation of phenols with the α and β anomers of penta-O-acetyl-D-glucopyranose, penta-O-trifluoroacetyl-D-glucopyranose, and 2,3,4,6-tetra-O-acetyl-1-O-trifluoroacetyl-D-glucopyranose in the presence of boron trifluoride etherate at varied temperature, time, and catalyst amount. The boron trifluoride etherate-catalyzed reaction of penta-O-acetyl-β -D-glucopyranose and 2,3,4,6-tetra-O-acetyl-1-O-trifluoroacetyl-β -D-glucopyranose with phenols occurs with a high stereocontrol to give, depending on conditions, predominantly 1,2-cis- or 1,2-trans-aryl-glycosides. This reaction can be used for preparative synthesis of the α- and β-anomeric forms of glycosides of a wide range of phenols.
- Sokolov,Zakharov,Studentsov
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p. 806 - 811
(2007/10/03)
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- Synthesis of anomeric sulfimides and their use as a new family of glycosyl donors
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We introduce a convenient synthesis of anomeric sulfimides, the ability of which to act as glycosyl donors has been tested with various thiophilic reagents and acceptors.
- Chery, Florence,Cassel, Stephanie,Wessel, Hans Peter,Rollin, Patrick
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p. 171 - 180
(2007/10/03)
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- The catalytic synthesis of aryl O-glycosides using triaryloxyboranes
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Triaryloxyboranes worked as highly reactive glycosyl acceptors of glycosyl acetates to afford aryl O-glycosides in excellent yields. A catalytic amount of ytterbium(III) trifluoromethanesulfonate activated the formation reaction of aryl O-glycosidic linka
- Yamanoi, Takashi,Yamazaki, Ippo
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p. 4009 - 4011
(2007/10/03)
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- C-glycoside analogs and methods for their preparation and use
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The invention provides versatile sialic acid C-glycoside precursors that are useful for preparing C-glycoside analogs of Gangliosides, peptides, and proteins, as well as synthetic intermediates useful for the preparation of the precursors, and synthetic m
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