- p-Nitrophenyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside
-
The crystal structure of p-nitrophenyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside, C20H23NO12, was determined in order to ascertain its stereochemistry. The ring adopts a 3C5 chair conformation, with
- Abboud, Khalil A.,Toporek, Stan S.,Horenstein, Benjamin A.
-
-
Read Online
- Nitrogen-containing aromatic ring derivative containing galactose and application thereof
-
The invention belongs to the technical field of medicines, and relates to a nitrogen-containing aromatic ring derivative containing galactose, application thereof and a pharmaceutical composition containing the compound. The invention also relates to a method for preparing the compound and the pharmaceutical composition, and application of the compound and the pharmaceutical composition in prevention or treatment of tumors, inflammatory diseases, autoimmune diseases and other diseases, especially tumors.
- -
-
Paragraph 0159; 0164-0168
(2021/06/09)
-
- Glucose-containing nitrogen-containing aromatic ring derivative and application thereof
-
The invention belongs to the technical field of medicines, and relates to a glucose-containing nitrogen-containing aromatic ring derivative and application thereof, and a pharmaceutical composition containing the compound. The invention also relates to a
- -
-
-
- 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)
-
- Chemo-enzymatic synthesis of p-nitrophenyl β-D-galactofuranosyl disaccharides from Aspergillus sp. fungal-type galactomannan
-
β-D-Galactofuranose (Galf) is a component of polysaccharides and glycoconjugates. There are few reports about the involvement of galactofuranosyltransferases and galactofuranosidases (Galf-ases) in the synthesis and degradation of galactofuranose-containing glycans. The cell walls of filamentous fungi in the genus Aspergillus include galactofuranose-containing polysaccharides and glycoconjugates, such as O-glycans, N-glycans, and fungal-type galactomannan, which are important for cell wall integrity. In this study, we investigated the synthesis of p-nitrophenyl β-D-galactofuranoside and its disaccharides by chemo-enzymatic methods including use of galactosidase. The key step was selective removal of the concomitant pyranoside by enzymatic hydrolysis to purify p-nitrophenyl β-D-galactofuranoside, a promising substrate for β-D-galactofuranosidase from Streptomyces species.
- Ota, Ryo,Okamoto, Yumi,Vavricka, Christopher J.,Oka, Takuji,Matsunaga, Emiko,Takegawa, Kaoru,Kiyota, Hiromasa,Izumi, Minoru
-
-
- Development of Pseudomonas aeruginosa Lectin LecA Inhibitor by using Bivalent Galactosides Supported on Polyproline Peptide Scaffolds
-
LecA is a galactose-binding tetrameric lectin from Pseudomonas aeruginosa involved in infection and biofilm formation. The emergent antibiotic resistance of P. aeruginosa has made LecA a promising pharmaceutical target to treat such infections. To develop LecA inhibitors, we exploit the unique helical structure of polyproline peptides to create a scaffold that controls the galactoside positions to fit their binding sites on LecA. With a modular scaffold design, both the galactoside ligands and the inter-ligand distance can be altered conveniently. We prepared scaffolds with spacings of 9, 18, 27, and 36 ? for ligand conjugation and found that glycopeptides with galactosides ligands three helical turns (27 ?) apart best fit LecA. In addition, we tested different galactose derivatives on the selected scaffold (27 ?) to improve the binding avidity to LecA. The results validate a new multivalent scaffold design and provide useful information for LecA inhibitor development.
- Huang, Shao-Feng,Lin, Cin-Hao,Lai, Yu-Tsung,Tsai, Chia-Lung,Cheng, Ting-Jen R.,Wang, Sheng-Kai
-
p. 686 - 700
(2018/03/05)
-
- Beta-galactosidase-responsive synthetic biomarker for targeted tumor detection
-
Tumor biomarkers are highly desirable for the screening of patients with a risk of tumor development and progression. Here, we report a beta-galactosidase (β-gal)-responsive acetaminophen (β-GR-APAP) as a synthetic plasma biomarker for targeted tumor detection. Tumor β-gal labeling via the recognition of tumor-related antigen enabled the detection of a tumor using β-GR-APAP.
- Nishihara, Tatsuya,Kuno, Satoshi,Nonaka, Hiroshi,Tabata, Sho,Saito, Natsumi,Fukuda, Shinji,Tomita, Masaru,Sando, Shinsuke,Soga, Tomoyoshi
-
supporting information
p. 11745 - 11748
(2018/11/25)
-
- Diazepinium perchlorate: a neutral catalyst for mild, solvent-free acetylation of carbohydrates and other substances
-
Diazepinium perchlorate, an essentially neutral organic salt possessing excellent stability, has been found to be well suited for the acetylation of free as well as partially protected sugars, phenols, thiophenols, thiols and other alcohols as well as amines. The diazepinium perchlorate-catalyzed acetylation is mild, organic and solvent-free and leaves acid sensitive protecting groups such as TBDMS/TBDPS/Tr ethers and isopropylidene/benzylidene acetals present on a substrate unaffected. Regioselective hydroxyl protection in partially protected carbohydrate derivatives/polyhydroxylic compounds was possible and was proved to be a convenient time-saving alternative to the conventional synthesis of such compounds. Easy preparation of the catalyst, mild reaction conditions and an environmentally benign protocol are some of the notable features of this reaction. The results obtained on the acetylation of phenols and thiophenols could be rationalized through their local nucleophilicity index obtained from DFT calculations.
- Giri, Santosh Kumar,Gour, Rajesh,Kartha, K. P. Ravindranathan
-
p. 13653 - 13667
(2017/03/11)
-
- Synthetic multivalent ligands for cholera & cholera-like toxins: Protected cyclic neoglycopeptides
-
Synthesis of a set of novel glycopeptide analogues as potential cholera/cholera-like toxin inhibitors in their protected form is described. They include di-, tri-, tetra- and pentavalent scaffolds. The synthetic steps were achieved using a combination of solvent-free mechanochemical as well as the conventional solution-phase reactions. During the conventional DIC-HOBt-mediated peptide coupling followed for the preparation of certain glycopeptide analogues an interesting in situ Fmoc deprotection was observed which has been demonstrated to hold potential for synthesiszing glycopeptides/neoglycopeptides with extended polyamide chains.
- Kumar, Vajinder,Yadav, Narender,Kartha, K.P. Ravindranathan
-
-
- Preparation method of galactose-containing fatty acid derivative and application of preparation method in field of medicine
-
The invention relates to a novel p-fatty alkylamide phenyl-beta-D-galactoside compound, a preparation method and application, belonging to the technical field of medicine. A structure general formula of the compound is shown in the description, wherein R is selected from (CH2)6CH3, (CH2)10CH3, (CH2)12CH3, (CH2)14CH3, and (CH2)7CH=CH (CH2)7CH3. The compound has stronger inhibitory activity to tumor cells, and can be used for tumor therapies.
- -
-
Paragraph 0023; 0024; 0042; 0043
(2016/12/01)
-
- Glycosylated lanthanide cyclen complexes as luminescent probes for monitoring glycosidase enzyme activity
-
The development of synthetic chemical probes for the detection of enzymes is extremely important for biological, medicinal, and industrial applications. Here we report the synthesis of an array of novel glycosylated Tb(iii) complexes, their photophysical properties in solution, and their ability to function as luminescent probes for observing glycosidase enzyme activity in real time. Our initial studies into the application of these complexes for the detection of the Concanavalin A (ConA) lectin is also reported, highlighting the broad scope of these novel chemical probes.
- Burke, Helen M.,Gunnlaugsson, Thorfinnur,Scanlan, Eoin M.
-
p. 9133 - 9145
(2016/10/07)
-
- Development and optimization of a competitive binding assay for the galactophilic low affinity lectin LecA from: Pseudomonas aeruginosa
-
Infections with the Gram-negative bacterium Pseudomonas aeruginosa result in a high mortality among immunocompromised patients and those with cystic fibrosis. The pathogen can switch from planktonic life to biofilms, and thereby shields itself against antibiotic treatment and host immune defense to establish chronic infections. The bacterial protein LecA, a C-type lectin, is a virulence factor and an integral component for biofilm formation. Inhibition of LecA with its carbohydrate ligands results in reduced biofilm mass, a potential Achilles heel for treatment. Here, we report the development and optimization of a fluorescence polarization-based competitive binding assay with LecA for application in screening of potential inhibitors. As a consequence of the low affinity of d-galactose for LecA, the fluorescent ligand was optimized to reduce protein consumption in the assay. The assay was validated using a set of known inhibitors of LecA and IC50 values in good agreement with the known Kd values were obtained. Finally, we employed the optimized assay to screen sets of synthetic thio-galactosides and natural blood group antigens and report their structure-activity relationship. In addition, we evaluated a multivalent fluorescent assay probe for LecA and report its applicability in an inhibition assay.
- Joachim, Ines,Rikker, Sebastian,Hauck, Dirk,Ponader, Daniela,Boden, Sophia,Sommer, Roman,Hartmann, Laura,Titz, Alexander
-
p. 7933 - 7948
(2016/08/30)
-
- Glucose fatty acid-containing derivative preparation method and application of derivative in medical field
-
The invention relates to a novel p-fatty alkyl amidophenyl-beta-D-glucoside compound and a preparation method and an application thereof, which belong to the technical field of medicine. According to the invention, a structural general formula is shown as
- -
-
Paragraph 0045; 0046
(2016/10/10)
-
- Synthesis and inhibitory activity evaluation of 2,6-disubstituted purine derivatives
-
A series of novel 2,6-disubstituted purine derivatives were designed and synthesized from 2,6-dichloropurine. The structures of target compounds were determined by 1H-NMR, 13C-NMR, and HRMS. The synthesized compounds were evaluated for their inhibitory activities against lung cancer cell lines of A549 and liver cancer cell lines of Bel-7402. 2-(4-Benzyloxy-phenylamino)-6-(cyclohexylamino)purine(3), 2-(4-chloro-phenylamino)-6-(n-butylamino)purine (5), 2-(4-morpholinoamino)-6-(4-hydroxy-phenylamino)purine (9), and 2-(4-O-galactosyl-phenylamino)-6-(cyclohexylamino)purine (12) exhibited moderate inhibitory activity.
- Liu, Hongxia,Li, Libo,Qurat-Ul-Ain, Shaikh,Jiang, Tao
-
p. 473 - 477
(2015/03/30)
-
- CARBOHYDRATE FUNCTIONALISED SURFACES
-
Carbohydrates are biomolecules that are involved in a range of biological processes and play key roles in, for instance, host immune response and cellular adhesion. Accordingly, functionalisation of medical devices such as stents, valves, catheters, prostheses and other devices for in vivoimplantation with carbohydrates is an area in which considerable interest is developing. Disclosed herein are surfaces having carbohydrates immobilised thereon. The carbohydrate has a linker moiety covalently bound thereto and the linker moiety has a carbon atom that forms a covalent bond with an atom on the target surface. The carbon based bond is a strong, non-hydrolysable covalent bond. Diazonium salts are utilised to produce the functionalised surfaces and they are particularly advantageous as they result in non-toxic readily escapable by-products
- -
-
Paragraph 0200-0202
(2014/09/29)
-
- Synthesis of cross-linked glycopeptides and ureas by a mechanochemical, solvent-free reaction and determination of their structural properties by TEM and X-ray crystallography
-
A highly efficient and cost-effective green method for the synthesis of complex glycopeptides and ureas mediated by carbonyl diimidazole under solvent-free conditions is reported. The reactions could be performed conveniently in a planetary ball mill by dry grinding, and the isolation of the novel sugar derivatives thus produced could be very efficiently achieved by size exclusion chromatography with environmentally benign substances. A diacetone galactose based diamide, upon crystallization, could be examined by X-ray crystallography and was found to possess a heart-shaped structure. Although the 4-aminophenyl galactoside based diamide synthesized formed spherical particles, the alanine-based diamide formed nanofilamentous/-tubular structures as analyzed by TEM imaging.
- Kumar, Vajinder,Giri, Santosh Kumar,Venugopalan, Paloth,Kartha, K.P. Ravindranathan
-
p. 1605 - 1613
(2015/02/02)
-
- Carbohydrate coatings via aryldiazonium chemistry for surface biomimicry
-
Carbohydrates are extremely important biomolecules and their immobilization onto solid surfaces is of interest for the development of new biomimetic materials and of new methods for understanding processes in glycobiology. We have developed an efficient surface modification methodology for the functionalization of a range of materials with biologically active carbohydrates based on aryldiazonium chemistry. We describe the synthesis and characterization of carbohydrate reagents, which were subsequently employed for the one-step, solution-based modification of carbon, metals, and alloys with monosaccharides. We used a combination of spectroscopic and nanogravimetric methods to characterize the structure of the carbohydrate layers; we report an average surface coverage of 7.8 × 10-10 mol cm-2 under our experimental conditions. Concanavalin A, a mannose-binding lectin, and Peanut Agglutinin, a galactose-binding lectin, were found to bind from solution to their respective monosaccharide binding partners immobilized at the surface. This result suggests that the spontaneous chemisorption of aryldiazonium monosaccharide precursors leads to the formation of monosaccharide layers that retain the biological recognition specificity of the parent carbohydrate molecule. Finally, we carried out measurements using fluorescently labeled Bovine Serum Albumin (BSA) and found that these carbohydrate coatings reduce unspecific adsorption of this protein at carbon surfaces. These results suggest that aryldiazonium-derived carbohydrate coatings may offer a promising strategy for preventing undesirable protein accumulation onto surfaces.
- Jayasundara, Dilushan R.,Duff, Thomas,Angione, M. Daniela,Bourke, Jean,Murphy, Deirdre M.,Scanlan, Eoin M.,Colavita, Paula E.
-
p. 4122 - 4128
(2013/11/19)
-
- Glycosylated tris-bipyridine ferrous complexes to provide dynamic combinatorial libraries for probing carbohydrate-carbohydrate interactions
-
2,2-Bipyridines having β-lactoside, β-d-glucoside, β-d-galactoside, and N-acetyl-β-d-glucosaminide were prepared and then, complexed with ferrous ion to afford trivalent glycoclusters having tris-bipyridine ferrous complex cores. Each glycocluster provides a dynamic combinatorial library composed of four diastereomeric stereoisomers (Δmer, Δfac, Λmer, and Λfac) whose ratios depend on their relative stabilities. CD spectral analyses of these glycoclusters showed that various cations (Na+, Mg2+, K+ or Ca2+) enriched Δ-forms of the glycocluster having β-lactosides and N-acetyl-β-d-glucosaminides possibly by cations-induced intramolecular carbohydrate-carbohydrate interactions.
- Nakamura, Motomi,Tsutsumi, Mayuka,Ishikawa, Yoshiaki,Umemiya, Haruka,Izawa, Kazumi,Abe, Haruka,Togashi, Yosuke,Kinone, Tatsuya,Sekiguchi, Sho,Igumi, Mihiro,Ide, Kanako,Hasegawa, Teruaki,Hasegawa, Toki
-
p. 3019 - 3026
(2013/03/29)
-
- Use of iodine for efficient and chemoselective glycosylation with glycosyl ortho-alkynylbenzoates as donor in presence of thioglycosides
-
A novel and high yielding glycosylation protocol with glycosyl ortho-alkynylbenzoates as donors and iodine as promoter is described. The donors are stable and can be chemoselectively activated in the presence of thioethyl and thiophenyl glycosides. The application of this methodology in one-pot consecutive glycosylation reaction is described.
- Dutta, Samrat,Sarkar, Swarbhanu,Gupta, Shyam Ji,Sen, Asish Kumar
-
supporting information
p. 865 - 870
(2013/02/25)
-
- GLYCOMIMETIC COMPOUNDS AS ANTI-INFECTIOUS AGAINST PATHOGENS LECTINS
-
The present invention relates to a calixarene-based glycosylated compound (I) having the formula: (I) wherein D is independently selected in the group comprising a —CH2-group, an oxygen atom, a sulphur atom, a sulfinyl group or a sulfonyl group, E is independently selected in the group comprising a hydrogen, an alkyl having from 1 to 10 carbon atoms, an aryl having from 6 to 20 carbon atoms, a nitrogen dioxide group, an azide group, an amino group, a guanidinium group, a halogen atom, a —CH2R group wherein R is a hydroxyl, a halogen, an amino group, a N(alkyl)2 group, a NH(alkyl) group, or E represents a —CO—R′ wherein R′ is a hydrogen atom, a hydroxyl group or an amino, B represents a A-C group wherein A is independently selected in the group comprising an oxygen atom, a sulfur atom, a NH group or a (CH2)i group, i being an integer from 1 to 10, C is independently selected in the group comprising a hydrogen, an alkyl, an alkenyl, an alkynyl, or C is a group of formula (II). The present invention also relates to a pharmaceutical composition characterized in that it comprises the said calixarene-based glycosylated compound (I), in combination with pharmaceutically acceptable carriers or diluents. The present invention also relates to the use of the said calixarene-based glycosylated compound (I) or the said pharmaceutical composition, for the manufacture of a drug intended to prevent or treat bacterial infections from pathogens that use lectins in the first steps of infection.
- -
-
Paragraph 0159-0161
(2013/10/07)
-
- Glycosynthase with broad substrate specificity-an efficient biocatalyst for the construction of oligosaccharide library
-
A versatile glycosynthase (TnG-E338A) with strikingly broad substrate scope has been developed from Thermus nonproteolyticus β-glycosidase (TnG) by using site-directed mutagenesis. The practical utility of this biocatalyst has been demonstrated by the facile generation of a small library containing various oligosaccharides and a steroidal glycoside (total 25 compounds) in up to 100 % isolated yield. Moreover, an array of eight gluco-oligosaccharides has been readily synthesized by the enzyme in a one-pot, parallel reaction, which highlights its potential in the combinatorial construction of a carbohydrate library that will assist glycomic and glycotherapeutic research. Significantly, the enzyme provides a means by which glycosynthase technology may be extended to combinatorial chemistry.
- Wei, Jinhua,Lv, Xun,Lue, Yang,Yang, Gangzhu,Fu, Lifeng,Yang, Liu,Wang, Jianjun,Gao, Jianhui,Cheng, Shuihong,Duan, Qian,Jin, Cheng,Li, Xuebing
-
supporting information
p. 2414 - 2419
(2013/05/23)
-
- Rational design and synthesis of optimized glycoclusters for multivalent lectin-carbohydrate interactions: Influence of the linker arm
-
The design of multivalent glycoclusters requires the conjugation of biologically relevant carbohydrate epitopes functionalized with linker arms to multivalent core scaffolds. The multigram-scale syntheses of three structurally modified triethyleneglycol analogues that incorporate amide moiety(ies) and/or a phenyl ring offer convenient access to a series of carbohydrate probes with different water solubilities and rigidities. Evaluation of flexibility and determination of preferred conformations were performed by conformational analysis. Conjugation of the azido-functionalized carbohydrates with tetra-propargylated core scaffolds afforded a library of 18 tetravalent glycoclusters, in high yields, by CuI-catalyzed azide-alkyne cycloaddition (CuAAC). The compounds were evaluated for their ability to bind to PA-IL (the LecA lectin from the opportunistic pathogen Pseudomonas aeruginosa). Biochemical evaluation through inhibition of hemagglutination assays (HIA), enzyme-linked lectin assays (ELLA), surface plasmon resonance (SPR), and isothermal titration microcalorimetry (ITC) revealed improved and unprecedented affinities for one of the monovalent probes (Kd=5.8 μM) and also for a number of the tetravalent compounds that provide several new nanomolar ligands for this tetrameric lectin. Copyright
- Cecioni, Samy,Praly, Jean-Pierre,Matthews, Susan E.,Wimmerova, Michaela,Imberty, Anne,Vidal, Sebastien
-
supporting information; experimental part
p. 6250 - 6263
(2012/07/03)
-
- GLYCOMIMETIC COMPOUNDS AS ANTI-INFECTIOUS AGAINST PATHOGENS LECTINS
-
The present invention relates to a calixarene-based glycosylated compound (I) having the formula : (I) wherein D is independently selected in the group comprising a –CH2 –group, an oxygen atom, a sulphur atom, a sulfinyl group or a sulfonyl group, E is independently selected in the group comprising a hydrogen, an alkyl having from 1 to 10 carbon atoms, an aryl having from 6 to 20 carbon atoms, a nitrogen dioxide group, an azide group, an amino group, a guanidinium group,a halogen atom, a –CH2 R group wherein R is a hydroxyl, a halogen, an amino group, a N(alkyl)2 group, a NH(alkyl) group, or E represents a –CO-R' wherein R' is a hydrogen atom, a hydroxyl group or an amino, B represents a A–C group wherein A is independently selected in the group comprising an oxygen atom, a sulfur atom, a NH group or a (CH2 )i group, i being an integer from 1 to 10, C is independently selected in the group comprising a hydrogen, an alkyl, an alkenyl, an alkynyl, or C is a group of formula (II). The present invention also relates to a pharmaceutical composition characterized in that it comprises the said calixarene-based glycosylated compound (I), in combination with pharmaceutically acceptable carriers or diluents. The present invention also relates to the use of the said calixarene-based glycosylated compound (I) or the said pharmaceutical composition, for the manufacture of a drug intended to prevent or treat bacterial infections from pathogens that use lectins in the first steps of infection.
- -
-
Page/Page column 23
(2012/06/30)
-
- 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
-
-
- Selective α-glucosidase substrates and inhibitors containing short aromatic peptidyl moieties
-
We constructed a library of sugar-dipeptide conjugate to find out the best complementary against hydrophobic pocket of α-glucosidase. The best substrate showed 150-fold improved Km value relative p-acetaminophenyl-α-d-glucopyranoside for α-glucosidase from Bacillus stearothermophillus. Using information from the complementary, we synthesized sp-WY and β-Glc-sp-WY, which selectivity inhibited the cognate enzyme.
- Park, Sangeun,Hyun, Soonsil,Yu, Jaehoon
-
supporting information; experimental part
p. 2441 - 2444
(2011/06/17)
-
- 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)
-
- 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)
-
- Application of halide molten salts as novel reaction media for O-glycosidic bond formation
-
In this study we have explored the application of halide molten salts as reaction media for O-glycosidic bond formation under basic conditions and mild heating. Eighteen different room-temperature ionic liquids and molten salts, representing four different classes of cations (i.e. imidazolium, pyridinium, pyrrolidinium and ammonium), were screened in the glycosidation reaction of p-nitrophenol with aceto-bromo-α-D-galactose. 1-Butyl-4-methylimidazolium chloride (BMIM·Cl) gave the best results and was applied in the reactions of other phenolic substrates to give the products with up to 80% yields. All the reactions were highly selective to give the β-anomers, and the molten salt BMIM·Cl could easily be reused with no apparent loss in activity.
- Kumar, Vineet,Talisman, Ian Jamie,Malhotra, Sanjay V.
-
supporting information; experimental part
p. 3377 - 3381
(2010/08/19)
-
- Solvent-free mechanochemical synthesis of aryl glycosides
-
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
-
experimental part
p. 411 - 419
(2009/04/11)
-
- Stabilization of an asymmetric bolaamphiphilic sugar-based crown ether hydrogel by hydrogen bonding interaction and its sol-gel transcription
-
Asymmetric bolaamphiphilic sugar-based hydrogelators (1-3) were synthesized and their gelation ability with and without alkylammonium ions was investigated by CD, TEM, FTIR and NMR. These compounds acted as versatile gelators for organic solvents and wate
- Jung, Jong Hwa,Rim, Jeong Ah,Cho, Eun Jin,Lee, Soo Jin,Jeong, Il Yun,Kameda, Naohiro,Masuda, Mitsutoshi,Shimizu, Toshimi
-
p. 7449 - 7456
(2008/02/05)
-
- Hydrogel behavior of a sugar-based gelator by introduction of an unsaturated moiety as a hydrophobic group
-
The new sugar-based gelators 1 and 2 were synthesized, and their gelation abilities were evaluated in organic solvents and in water. Compound 1 gelates both water and organic solvents whereas 2 gelates only organic solvents. Superstructural difference between hydrogel 1 and organogel 2 was investigated by CD, TEM, AFM, 1H NMR and XRD. Hydrogel 1 displays a well-developed helical ribbon structure with 20-150 nm diameter and a length of several hundred m whereas organogel 2 shows a twisted fiber structure of diameter 20 nm. CD measurements of hydrogel 1 and organogel 2 indicate that hydrogel 1 maintains a well-ordered chiral structure whereas organogel 2 maintains a relatively disordered chiral structure. The 1H NMR and XRD results suggest that the hydrophobic interaction in hydrogel 1 are relatively weak, with a relatively small region interdigitated between lipophilic alkyl groups. In addition, upon irradiation at 254 nm wavelength, hydrogel 1 reveals a red coloration at 540 nm. These results indicate that the self-assembled hydrogel 1 was polymerized by UV-irradiation. The intensity of the CD spectrum of the polymerized hydrogel markedly decreased. This result indicates that upon polymerization the highly ordered chiral structure of hydrogel 1 changes to a disordered molecular packing structure. The Royal Society of Chemistry 2006.
- Jung, Jong Hwa,Rim, Jeong Ah,Han, Won Seok,Lee, Soo Jin,Lee, Young Joo,Cho, Eun Jin,Kim, Jong Seung,Ji, Qingmin,Shimizu, Toshimi
-
p. 2033 - 2038
(2008/10/09)
-
- Crystal structure and solid state 13C NMR analysis of nitrophenyl 2,3,4,6-tetra-O-acetyl-β-D-gluco- and D-galactopyranosides
-
The X-ray diffraction analysis of o-nitrophenyl 2,3,4,6-tetra-O-acetyl- β-d-galactopyranoside (1), m-nitrophenyl 2,3,4,6-tetra-O-acetyl-β-d- galactopyranoside, p-nitrophenyl 2,3,4,6-tetra-O-acetyl-β-d- galactopyranoside and o-nitrophenyl 2,3,4,6-tetra-O-a
- Temeriusz, Andrzej,Gubica, Tomasz,Rogowska, Paulina,Paradowska, Katarzyna,Cyranski, Michal K.
-
p. 1175 - 1184
(2007/10/03)
-
- Sol-Gel Polycondensation of Tetraethyl Orthosilicate (TEOS) in Sugar-Based Porphyrin Organogels: Inorganic Conversion of a Sugar-Directed Porphyrinic Fiber Library through Sol-Gel Transcription Processes
-
Sugar-appended porphyrins (1a-e) with monosaccharide groups at their periphery have been rationally designed for a new class of gelating reagents. A few of these compounds have the tendancy to form one-dimensional aggregates stable enough to show successful gelation ability for DMF-alcohol mixed solvents. The aggregation mode in the specific columnar super structures has been evaluated in detail by UV-visible spectrometry (UV/Vis), circular dichroism (CD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). All UV-visible spectra of sugar-appended porphyrinic gels obtained from la-c exhibit Soret band absorptions, which shift to lower wave-length and are significantly broadened. This phenomenon indicates that these porphyrin cores strongly interact with each other in an H-aggregate fashion, which drives the generation of a one-dimensional porphyrin-stacking array. The CD spectra of the organogels from 1a and 1b, which are in anomers, exhibit an almost symmetric pattern, whereas the gel from 1c gives a completely different pattern. This implies that the gel fibrils wind themselves in a right- or left-handed fashion; this reflects chirality in the specific molecular structure of the gelators. The results from SEM for the gel fibrils are in good agreement with the CD patterns. The gel fibrils in la possess left-handed helicity, whereas those in lb wind themselves right-handedly. Macroscopic helical morphology reflects the microscopic structure well at a molecular level, which gives structural variety of the gel fibrils, which can be defined by the sugar library. Inorganic conversion of the organic helical fibrils by a sol-gel transcription process successfully gives the helical-silica structures, which finely inherit the organic morphology. A striking observation is that a unimolecular porphyrin-stacking array is also transcribed into silica fibers when the optimized sol-gel reaction conditions are selected. A sugar-based organic-fiber library in porphyrinic gels thus provides a variety of inorganic materials through the sol-gel transcription process.
- Kawano, Shin-Ichiro,Tamaru, Shun-Ichi,Fujita, Norifumi,Shinkai, Seiji
-
p. 343 - 351
(2007/10/03)
-
- 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
-
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
-
p. 806 - 811
(2007/10/03)
-
- Synthesis and utility of sulfated chromogenic carbohydrate model substrates for measuring activities of mucin-desulfating enzymes
-
A chromogenic substrate, 4-nitrophenyl 2-acetamido-2-deoxy-β-D-glucopyranoside 6-sodium sulfate was synthesized and used in combination with β-N-acetylhexosaminidase for detection of the sulfatase, MdsA, by release of 4-nitrophenol. MdsA was originally isolated from the bacterium Prevotella strain RS2 and is believed to be involved in desulfation of sulfomucins, major components of the mucus barrier protecting the human colon surface. The exo nature of the MdsA sulfatase was indicated by its inability to de-esterify the disaccharide 4-nitrophenyl β-D-galactopyranosyl-(1→4)-2-acetamido-2-deoxy-β-D- glucopyranoside 6-sodium sulfate. This latter compound was prepared from monosaccharide precursors by two different methods, the shorter requiring just six steps from 4-nitrophenyl 2-acetamido-2-deoxy-β-D-glucopyranoside and giving an overall yield of 26.4%. The syntheses of 4-nitrophenyl β-D-galactopyranoside 3-triethylammonium sulfate and 6-triethylammonium sulfate and their use in combination with β-galactosidase as chromogenic substrates for detecting Bacteroides fragilis sulfatases with different specificities was also demonstrated.
- Clinch, Keith,Evans, Gary B,Furneaux, Richard H,Rendle, Phillip M,Rhodes, Phillippa L,Roberton, Anthony M,Rosendale, Douglas I,Tyler, Peter C,Wright, Damian P
-
p. 1095 - 1111
(2007/10/03)
-
- Synthesis and biological activity of glycosyl conjugates of N-(4-hydroxyphenyl)retinamide
-
Three glycosyl (glucosyl, galactosyl, mannosyl) conjugates of 4-hydroxyphenylretinamide have been synthesized and tested on a broad variety of tumor cells. All three compounds are active on promyelocytic leukemia cell lines HL60 but less than the parent compound 4-HPR. Among them, the mannosyl analog stands out by its very low toxicity. Copyright
- Winum, Jean-Yves,Leydet, Alain,Seman, Michel,Montero, Jean-Louis
-
p. 319 - 324
(2007/10/03)
-
- New organogelators bearing both sugar and cholesterol units: An approach toward molecular design of universal gelators
-
The gelators of organic solvents are classified into two categories on the basis of their basic intermolecular forces: hydrogen-bonded or nonhydrogen-bonded. To utilize these two interactions cooperatively for organogel formation we newly synthesized seven gelators (1-7) and two reference compounds (8 and 9) which have both a cholesterol moiety and a saccharide moiety within one molecule. The solubility of 1-7 changed drastically from totally insoluble one to very soluble one depending on the saccharide absolute configuration. In general, the gelator became very insoluble when it includes many equatorial OH groups, whereas it became very soluble when it includes many axial OH groups. Gelators 2 and 5 bearing two equatorial OH groups and one axial OH group acted as good gelators and in several cases the sol-gel phase-transition temperatures (measured in a sealed tube) were higher than the boiling points. The SEM observations of the xerogels established that the stable gels contain the entangled fibrous network. These results indicate that a very stable organogel can be designed by a cooperative coagulative effect of a cholesterol-cholesterol interaction and a saccharide-saccharide interaction.
- Amaike,Kobayashi,Shinkai
-
p. 2553 - 2558
(2007/10/03)
-
- Simple syntheses of indol-1-yl glucosides
-
A lithium hydroxide promoted glucosidation of 1-hydroxyindoles with 2, 3, 4, 6-tetra-0-acetyl-α-D-glucopyranosyl bromide is newly developed. Applying this method, the first and simple syntheses of novel indol-1-yl glucosides were achieved.
- Yamada, Fumio,Hayashi, Toshikatsu,Yamada, Koji,Somei, Masanori
-
p. 1881 - 1884
(2007/10/03)
-
- Highly efficient β-glucosylation of the acidic hydroxyl groups, phenol and carboxylic acid, with an peracetylated glucosyl fluoride using a combination of BF3·Et2O and DTBMP as a promoter
-
A combination of BF3·Et2O and DTBMP was established to be an efficient promoter of β-glucosylation of both phenols and carboxylic acids with a peracetylated glucosyl fluoride (2). This new method achieved remarkably high yields and β
- Oyama, Kin-Ichi,Kondo, Tadao
-
p. 1627 - 1629
(2007/10/03)
-
- The improved synthesis of β-D-Glucuronides using TEMPO and t-butyl hypochlorite
-
TEMPO/t-BuOCl is used to oxidise β-D-glucosides to β-D-glacuronides in high yield as a pivotal step in the preparation of labelled glucuronides from labelled glucose samples.
- Melvin,McNeill,Henderson,Herbert
-
p. 1201 - 1202
(2007/10/03)
-
- Solid-liquid phase transfer catalyzed novel glycosylation reaction of phenols
-
A facile and mild glycosylation reaction in solid-liquid two-phase system (powdered K2CO3/CHCl3) containing phase transfer catalyst was found to be efficient for preparation of glucosides of 2', 6'-dihydroxyacetophenone (1) and other various substituted phenols.
- Hongu, Mitsuya,Saito, Kunio,Tsujihara, Kenji
-
p. 2775 - 2781
(2007/10/03)
-
- A facile access to aryl α-sialosides: The combination of a volatile amine base and acetonitrile in glycosidation of sialosyl chlorides
-
We have succeeded in achieving a facile access to 4-nitrophenyl and 4-methylumbelliferyl-α-sialosides. To sialosyl chlorides which are fully protected with acetyl groups as glycosyl donors, the action of phenols with diisopropylethylamine in acetonitrile brought about high yield as well as facile product isolation.
- Kuboki, Atsuhito,Sekiguchi, Takahiro,Sugai, Takeshi,Ohta, Hiromichi
-
p. 479 - 482
(2007/10/03)
-
- Iodine : A versatile reagent in carbohydrate chemistry IV. Per-O-Acetylation, regioselective acylation and acetolysis
-
Iodine has been found to be an effective Lewis acid for promoting the per-O-acetylation of unprotected sugars. Under controlled conditions it can bring about regioselective acylation of carbohydrate derivatives. At higher concentration and with longer reaction times, iodine can effect the selective acetolysis of benzyl ether-protected primary hydroxyl groups. All of these reactions proceed in high yield, are easy to carry out and make use of readily available iodine, which is both cheap and easy to handle.
- Kartha, K. P. Ravindranathan,Field, Robert A.
-
p. 11753 - 11766
(2007/10/03)
-
- Reliable method for the synthesis of aryl β-D-glucopyranosides, using boron trifluoride-diethyl ether as catalyst
-
Stereospecific formation of aryl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosides was achieved by reaction of penta-O-acetyl-β-D-glucose 1 with substituted phenols in the presence of boron trifluoride. Yields of the purified products varied from 52-85%. Benzyl alcohol could also be glucosylated using similar conditions. All products were purified by crystallization from ethanol. The purity and the anomeric configuration of the products were determined by means of 1H and 13C NMR spectroscopy, melting points and optical rotation.
- Smits, Elly,Engberts, Jan B. F. N.,Kellogg, Richard M.,Van Doren, Henk A.
-
p. 2873 - 2877
(2007/10/03)
-
- Glycosides. Part 1. New Synthesis of 1,2-trans O-Aryl Glycosides, via Tributyltin Phenoxides
-
A new method of glycosidation of phenols has been studied.The reaction of tributyltin phenoxides 2 with 1,2,3,4,6-penta-O-acetyl-D-hexopyranosides 3, 7 and 9, in the presence of tin tetrachloride is described.Glycosides 4, 8 and 10 have been isolated in g
- Clerici, Francesca,Gelmi, Maria Luisa,Mottadelli, Sabrina
-
p. 985 - 988
(2007/10/02)
-
- Studies on glycosides. X. An alternative method for highly stereoselective synthesis of alkyl-β-D-glucopyranosides
-
An alternate method for the synthesis of alkyl-β-D-glucopyranosides using 2,3,4,6-tetra-O-acetyl-1-O-trifluoroacetyl-α-D-glucopyranose with alcohols or phenols in the presence of Lewis acid at low temperature was reported. β-anomers were the sole product
- Li,Cai,Cai
-
p. 2121 - 2124
(2007/10/02)
-
- Syntheses and Transformations of Glycohydrolase Substrates into Protein Conjugates Based on Michael Additions
-
The glycosyl chloride 1 and bromides 2 and 3 were stereospecifically transformed into p-nitrophenyl glycosides by phase transfer catalysis; these glycohydrolase substrates were reduced and N-acryloylated to afford Michael acceptors which reacted with amine functions of proteins.
- Roy, Rene,Tropper, Francois D.,Morrison, Tara,Boratynski, Janusz
-
p. 536 - 538
(2007/10/02)
-
- Novel Synthesis of Aryl 2,3,4,6-Tetra-O-acetyl-D-glucopyranosides
-
The glucosidation of phenols with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl fluoride in the presence of BF3*OEt2 to give, predominantly, α-anomers has been studied.In the presence of an amine base, 1,1,3,3-tetramethylguanidine, however, enhanced β-selectivity was achieved.The former reaction provides a novel and useful synthesis of aryl 2,3,4,6-tetra-O-acetyl-α-D-glucopyranoside whilst the latter is effective for the glycosidation of relatively hindered phenols.
- Yamaguchi, Masahiko,Horiguchi, Akira,Fukuda, Akira,Minami, Toru
-
p. 1079 - 1082
(2007/10/02)
-
