- Synthetic transformations of higher terpenoids: XXXVI. Synthesis of furanolabdanoid glycoconjugates with a 1,2,3-triazole linker
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Procedures have been developed for the synthesis of 16-[(propargyloxy)methyl]- and 7- and 18-(propargyloxy)labda-8(9),13,14-trienes from phlomisoic acid. Copper-catalyzed cycloaddition of the labdanoid alkynes to azido derivatives of α-D-glucose, D-galactose, D-xylose, and L-arabinose afforded the corresponding N-glycosyl-1,2,3-triazole conjugates.
- Kremenko,Kharitonov, Yu. V.,Shul’ts
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- Design, synthesis and molecular docking analysis of flavonoid derivatives as potential telomerase inhibitors
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Based on the structural scaffolds of natural products, two series of flavonoid derivatives, for a total of twelve compounds, were designed and synthesized as potential human telomerase inhibitors. Using a modified TRAP-PCR assay, compound 5c exhibited the most potent inhibitory activity against human telomerase with an IC50 value of less than 50 μM. In vitro, the results demonstrated that compound 5c had potent anticancer activity against five classes of tumor cell lines. The molecular docking and molecular dynamics analyses binding to the human telomerase holoenzyme were performed to elucidate the binding mode of active compound 5c. This finding helps the rational design of more potent telomerase inhibitors based on the structural scaffolds of natural products.
- Cheng, Mao-Sheng,Fan, Zhan-Fang,Fu, Ya,Ho, Sai-Tim,Hu, Chun,Liu, Yang,Shaw, Pang-Chui,Wang, Jian,Wen, Rui,Zhang, Lei
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- Arabinose based gelators: Rheological characterization of the gels and phase selective organogelation of crude-oil
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Oil-spills, whether marine or terrestrial, result in major devastation to the environment and ecosystem, loss of habitat and damage to the economy. While inevitable in the current scenario, oil spillages necessitate prompt remedial action to limit the damage caused. A recent strategy towards this is to congeal the spilled oil into a gel through gelation (for terrestrial oil-spills) or through Phase Selective Organogelation (PSOG) for marine oil-spills which can stem the spread of the oil and also provide for the easy removal and reclamation of the gelled oil. Herein, we report two triazolylarabinoside derivatives that are stable, completely insoluble in water and can carry out the gelation as well as the PSOG of hydrocarbon based organic solvents, petrol, diesel and also crude-oil. The gels have been characterized thoroughly by optical microscopy, FESEM, AFM, XRD and rheological experiments. The gelation of crude-oil has also been unequivocally established via rheological studies. The easily synthesized and cheap triazolylarabinosides could provide simple gelators for the remediation of marine/terrestrial oil-spills.
- Rajkamal,Pathak, Navendu Prakash,Chatterjee, Debnath,Paul, Abhijit,Yadav, Somnath
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- Stereospecific synthesis of sugar-1-phosphates and their conversion to sugar nucleotides
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As Leloir glycosyltransferases are increasingly being used to prepare oligosaccharides, glycoconjugates, and glycosylated natural products, efficient access to stereopure sugar nucleotide donor substrates is required. Herein, the rapid synthesis and purification of eight sugar nucleotides is described by a facile 30 min activation of nucleoside 5′-monophosphates bearing purine and pyrimidine bases with trifluoroacetic anhydride and N-methylimidazole, followed by a 2 h coupling with stereospecifically prepared sugar-1-phosphates. Tributylammonium bicarbonate and tributylammonium acetate were the ion-pair reagents of choice for the C18 reversed-phase purification of 6-deoxysugar nucleotides, and hexose or pentose-derived sugar nucleotides, respectively.
- Timmons, Shannon C.,Jakeman, David L.
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- GUAIANOLIDE α-ARABINOPYRANOSIDES FROM HELENIUM AMARUM
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Key Word Index - Helenium amarum; Compositae; sesquiterpene lactones; pseudoguaianolides; guaianolide-α-arabinopyranosides; sesquiterpenes;seco-caryophyllenes; phenylpropane derivatives. - The aerial parts of Helenium amarum afforded, in addition to compounds reported previously, several known sesquiterpene lactones as well as some new ones, two pseudoguaianolides and a complex mixture of guaianolide α-arabinopyranosides, which differed in the position of the double bond, the configuration at C-8 and the position of an acetate group in the sugar moiety.Furthermoreseco-caryophyllenes and phenylpropane derivatives were isolated.The structures were elucidated by spectroscopic methods and few chemical transformations.
- Bohlmann, Ferdinand,Misra, Laxmi N.,Jakupovic, Jasmin,King, Robert M.,Robinson, Harold
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- S-Adamantyl Group Directed Site-Selective Acylation: Applications in Streamlined Assembly of Oligosaccharides
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The site-selective functionalization of carbohydrates is an active area of research. Reported here is the surprising observation that the sterically encumbered adamantyl group directed site-selective acylation at the C2 position of S-glycosides through dispersion interactions between the adamantyl C?H bonds and the π system of the cationic acylated catalyst, which may have broad implications in many other chemical reactions. Because of their stability, chemical orthogonality, and ease of activation for glycosylation, the site-selective acylation of S-glycosides streamlines oligosaccharide synthesis and will have wide applications in complex carbohydrate synthesis.
- Blaszczyk, Stephanie A.,Xiao, Guozhi,Wen, Peng,Hao, Hua,Wu, Jessica,Wang, Bo,Carattino, Francisco,Li, Ziyuan,Glazier, Daniel A.,McCarty, Bethany J.,Liu, Peng,Tang, Weiping
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- DMF promoted xylosylation of terpenols
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The glycosidation of 2,3,4-triacetyl-1-bromo-α-d-xylopyranose with various terpenols occurs at 50°C in DMF without the requirement of any additive. The decisive role of DMF as solvent on the coupling efficiency is highlighted.
- Satgé, Céline,Le Bras, Jean,Hénin, Fran?oise,Muzart, Jacques
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- The total synthesis of eleutherobin: A surprise ending
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An 'sp2-sp3 Stille coupling' of the vinyl triflate 1 and the stannyl compound 2 is a key step toward the completion of the total synthesis of eleutherobin, a natural product exhibiting taxol-like cytotoxic activity.
- Chen, Xiao-Tao,Zhou, Bishan,Bhattacharya, Samit K.,Gutteridge, Clare E.,Pettus, Thomas R. R.,Danishefsky, Samuel J.
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- Stereoselective synthesis of α- And β-glycofuranosyl amides by traceless ligation of glycofuranosyl azides
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A highly stereoselective synthesis of α- or β-glycofuranosyl amides based on the traceless Staudinger ligation of glycofuranosyl azides of the galacto, ribo, and arabino series with 2-diphenylphosphanyl-phenyl esters has been developed. Both α- and β-isomers can be obtained with excellent selectivity from a common, easily available precursor. The process does not depend on the anomeric configuration of the starting azide but appears to be controlled by the C2 configuration and by the protection/deprotection state of the substrates. A mechanistic interpretation of the results, supported by 31P NMR experiments, is offered and merged with our previous mechanistic analysis of pyranosyl azide ligation reactions. Copyright
- Nisic, Filippo,Speciale, Gaetano,Bernardi, Anna
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- Streamlined synthesis of per-O-acetylated sugars, glycosyl iodides, or thioglycosides from unprotected reducing sugars
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Solvent-free per-O-acetylation of sugars with stoichiometric acetic anhydride and catalytic iodine proceeds in high yield (90-99%) to give exclusively pyranose products as anomeric mixtures. Without workup, subsequent anomeric substitution employing iodine in the presence of hexamethyldisilane (i.e., TMS-I generated in situ) gives the corresponding glycosyl iodides in 75-95% isolated yield. Alternatively, and without workup, further treatment with dimethyl disulfide or thiol (ethanethiol or thiocresol) gives anomerically pure thioglycosides in more than 75% overall yield.
- Mukhopadhyay, Balaram,Kartha, K.P. Ravindranathan,Russell, David A.,Field, Robert A.
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- Exchange radioiodination produces inversion at C-4 of 1-(4-deoxy-4-iodo-β-D-xylopyranosyl)-2-nitroimidazole
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The title compound, 3a, when exchange labeled with 125I results in three new labeled products. The major labeled product (84.1%) is 1-(4-deoxy-4-iodo-β-L-arabinopyranosyl)-2-nitroimidazole, 3b, that could result from inversion of configuration at C-4. Exchange labeling carried out under conditions of kinetic control yielded dramatically different product ratios than thermodynamic equilibrium reactions. Confirmation of these results was established by extensive 1H NMR spectral analyses. A possible mechanism is presented. Copyright
- Schneider,Price,Chapman
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- Design and synthesis of DNA-intercalating 9-fluoren-β-O-glycosides as potential IFN-inducers, and antiviral and cytostatic agents
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Novel 9-fluoren-β-O-glycosides, designed as DNA-intercalating agents in structural correlation with antiviral tilorone and anticancer anthracyclines, have been prepared with yields in β-anomers ranging between 25 and 63%. They have been screened for antiproliferative, immunostimulating and antiviral properties against HSV-1 and HSV-2 viruses. Compounds displaying significant antiviral activity against HSV-2 are acetylated 1 and deprotected 6 9-fluorenyl-O-D-arabinopyranoses, whereas 9-fluorenyl-O-D-glucopyranose 3 is the most effective on HSV-1 replication, followed by 1 and 6. The conformational properties of these compounds have been evaluated by molecular modelling techniques.
- Alcaro,Arena,Neri,Ottana,Ortuso,Pavone,Vigorita
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- H2SO4-SiO2: Highly efficient and reusable catalyst for per-O-acetylation of carbohydrates under solvent-free conditions
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Sulfuric acid immobilized on silica gel (H2SO 4-SiO2) was used as an efficient promoter for per-O-acetylation of carbohydrates with acetic anhydride under solvent-free conditions. The substrates include not only monosaccharides and disaccharides, but also glycosides. The catalyst is recyclable and stable at room temperature, and the reaction protocol is simple, is cost-effective, and gives good isolated yield with high purity. The large-scale reactions also proceeded conveniently and in high yields. Taylor & Francis Group, LLC.
- Zhang, Jianbo,Zhang, Bo,Zhou, Jiafen,Li, Juan,Shi, Chunjuan,Huang, Ting,Wang, Zhongfu,Tang, Jie
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- Biotransformation of spirolaxine by Absidia cuneospora and Trametes hirsuta: Formation of β-glycosyl and β-xylosyl derivatives
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Incubation of spirolaxine 1a with the fungus Absidia cuneospora afforded 5β-glucosyl-spirolaxine 2b; the structure of the biotransformed product was deduced on the basis of MS, NMR data and chemical semi-synthesis. When using Trametes hirsuta as a bioagent 1a afforded 5β-xylosyl-spirolaxine 3a; the identification of the sugar moiety came from acidic hydrolysis of the new metabolite.
- Bava, Adriana,Nasini, Gianluca,Fronza, Giovanni
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- Novel stereoselective synthesis of glycosyl-1-O-acyl esters via peracetylglycosyl phosphorothioates, -selenoates and -dithioates as glycosyl donors
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An efficient and highly β-stereoselective synthesis of glycosyl 1-O-acyl esters based on reaction of easily accessible glycosylthio-, seleno- and dithiophosphates 1-6 as glycosyl donors with carboxylic acids 7-13 as glycosyl acceptors in the presence of silver salts as activators is described.
- Borowiecka, Joanna,Michalska, Maria
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- Synthesis of β-D-xylopyranoside thiophosphate derivatives
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A method of synthesis of β-D-xylopyranoside thiophosphate derivatives was developed. Biological testing revealed a high insecticidal activity in the synthesized compounds.
- Belakhov,Garabadzhiu,Boikova,Antonova
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- Metal-Catalyzed Organic Photoreactions. Iron (III)-Catalyzed Photoreactions of Aldo- and Ketohexoses
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Under UV irradiation in the presence of iron(III) chloride or iron (III) triflate in pyridine, D-glucose, D-mannose, and D-galactose underwent a selective bond cleavage at the C1-C2 position, producing 4-O-formyl-D-arabinopyranose and 4-O-formyl-D-lyxopyranose.D-Fructose, under the same conditions, gave arabino-γ-lactone.The reaction was interpreted in terms of the photoinduced electron transfer within a chelate of iron ion with the carbohydrate molecule.
- Ichikawa, Shuji,Tomita, Isao,Hosaka, Akira,Sato, Tadashi
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- The Readout of Base-Pair Information in Adenine-Thymine α- D -Arabinonucleosides
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Structurally modified nucleosides are central players in the field of nucleic acid chemistry. Adenine-thymine (AT) pyrimido[4,5-d]pyrimidine furanosyl and pyranosyl arabinonucleosides have been synthesized for the first time. Single-crystal X-ray diffraction analysis reveals novel base pairs that, in synergy with the sugar residues, direct the emergence of distinct networks containing channels and cavities. The microscopic noncovalent connections can be translated into macroscopic levels in which robust organogels are formed by the furanoside but not the pyranoside. The influences of the sugars are also displayed by the different shaped superstructures of the free nucleosides in solution. The readout of the information in the base moiety is therefore tailored by the sugar configuration, and the interplays exert subtle effects on the structures, from solid to gel and to the solution state. The potential for forming these appealing base pairs and higher structures enables these intriguing nucleosides to serve as unique building blocks in various areas or to construct innovative nucleic acid structures.
- He, Shiliang,Zhao, Hang,Guo, Xiurong,Xu, Xiaoping,Zhou, Xinglong,Liu, Jiang,Xing, Zhihua,Ye, Ling,Jiang, Lu,Chen, Qianming,He, Yang
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- Design, Synthesis, biological investigations and molecular interactions of triazole linked tacrine glycoconjugates as Acetylcholinesterase inhibitors with reduced hepatotoxicity
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Tacrine is a known Acetylcholinesterase (AChE) inhibitors having hepatotoxicity as main liability associated with it. The present study aims to reduce its hepatotoxicity by synthesizing tacrine linked triazole glycoconjugates via Huisgen's [3 + 2] cycloaddition of anomeric azides and terminal acetylenes derived from tacrine. A series of triazole based glycoconjugates containing both acetylated (A-1 to A-7) and free sugar hydroxyl groups (A-8 to A-14) at the amino position of tacrine were synthesized in good yield taking aid from molecular docking studies and evaluated for their in vitro AChE inhibition activity as well as hepatotoxicity. All the hybrids were found to be non-toxic on HePG2 cell line at 200 μM (100 % cell viability) as compared to tacrine (35 % cell viability) after 24 h of incubation period. Enzyme kinetic studies carried out for one of the potent hybrids in the series A-1 (IC50 0.4 μM) revealed its mixed inhibition approach. Thus, compound A-1 can be used as principle template to further explore the mechanism of action of different targets involved in Alzheimer's disease (AD) which stands as an adequate chemical probe to be launched in an AD drug discovery program.
- Ahmed, Ajaz,Bhagat, Kavita,Choudhary, Sushil,Kaur Gulati, Harmandeep,Kumar, Ajay,Kumar, Nitish,Mukherjee, Debaraj,Singh Bedi, Preet Mohinder,Singh, Atamjit,Singh, Harbinder,Vir Singh, Jatinder
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- Synthesis and biological evaluation of 3β-O-neoglycosides of caudatin and its analogues as potential anticancer agents
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In order to study the structure–activity relationship (SAR) of C21-steroidal glycosides toward human cancer cell lines and explore more potential anticancer agents, a series of 3β-O-neoglycosides of caudatin and its analogues were synthesized. The results revealed that most of peracetylated 3β-O-monoglycosides demonstrated moderate to significant antiproliferative activities against four human cancer cell lines (MCF-7, HCT-116, HeLa, and HepG2). Among them, 3β-O-(2,3,4-tri-O-acetyl-β-L-glucopyranosyl)-caudatin (2k) exhibited the highest antiproliferative activity aganist HepG2 cells with an IC50 value of 3.11 μM. Mechanical studies showed that compound 2k induced both apoptosis and cell cycle arrest at S phase in a dose dependent manner. Overall, these present findings suggested that glycosylation is a promising scaffold to improve anticancer activity for naturally occurring C21-steroidal aglycones, and compound 2k represents a potential anticancer agent deserved further investigation.
- Li, Xiao-San,Chen, Tang-Ji,Xu, Zhi-Peng,Long, Juan,He, Miao-Ying,Zhan, He-Hui,Zhuang, Hai-Cai,Wang, Qi-Lin,Liu, Li,Yang, Xue-Mei,Tang, Jin-Shan
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- Synthesis of podophyllotoxin-glycosyl triazoles via click protocol mediated by silver (I)-N-heterocyclic carbenes and their anticancer evaluation as topoisomerase-II inhibitors
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Herein we report the regioselective synthesis of podophyllotoxin-Glycosyl triazole hybrids catalysed by Ag(I)-N-heterocyclic carbene (Ag(I)-NHC) in a short reaction time (~30 min) at ambient conditions. In principle, it is the first report of Click alkyne-azide cycloaddition catalysed by Ag(I)-NHC catalyst and moreover, this new methodology yielded good results when compared with traditional CuAAC in terms of reaction time and selectivity. The synthesised compounds were further explored for in vitro anticancer activity against four human cancer cell lines Du145, HeLa, A-549, and MCF-7 and found that these synthesised compounds possess significant anticancer activity. Further, the compounds 5a and 5e were identified as promising leads due to their better activity across all cell lines than that of the standard drug etoposide. Molecular docking studies of 5a & 5e with DNA Topoisomerase-II were revealed that the free energy calculations of active compounds were in good agreement with observed IC50 values.
- Nerella, Srinivas,Kankala, Shravankumar,Gavaji, Brahmeshwari
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supporting information
p. 9 - 16
(2019/06/27)
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- Total Synthesis of (+)-Erogorgiaene and the Pseudopterosin A?F Aglycone via Enantioselective Cobalt-Catalyzed Hydrovinylation
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Due to their pronounced bioactivity and limited availability from natural resources, metabolites of the soft coral Pseudopterogorgia elisabethae, such as erogorgiaene and the pseudopterosines, represent important target molecules for chemical synthesis. We have now developed a particularly short and efficient route towards these marine diterpenes exploiting an operationally convenient enantioselective cobalt-catalyzed hydrovinylation as the chirogenic step. Other noteworthy C?C bond forming transformations include diastereoselective Lewis acid-mediated cyclizations, a Suzuki coupling and a carbonyl ene reaction. Starting from 4-methyl-styrene the anti-tubercular agent (+)-erogorgiaene (>98 % ee) was prepared in only 7 steps with 46 % overall yield. In addition, the synthesis of the pseudopterosin A aglycone was achieved in 12 steps with 30 % overall yield and, surprisingly, was found to exhibit a similar anti-inflammatory activity (inhibition of LPS-induced NF-κB activation) as a natural mixture of pseudopterosins A?D or iso-pseudopterosin A, prepared by β-D-xylosylation of the synthetic aglycone.
- Movahhed, Sohajl,Westphal, Julia,Kempa, Alexander,Schumacher, Christian Eric,Sperlich, Julia,Neud?rfl, J?rg-Martin,Teusch, Nicole,Hochgürtel, Matthias,Schmalz, Hans-Günther
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supporting information
p. 11574 - 11579
(2021/07/02)
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- Protecting carbohydrates with ethers, acetals and orthoesters under basic conditions
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Chlorinated ethyl and vinyl ethers are introduced at various positions of carbohydrates. Depending on the relative stereochemistry, vinylethers, acetals or orthoesters are formed under basic conditions. The products are stable, but are easily deprotected
- Liang, Yang,Pedersen, Christian M.
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supporting information
p. 7598 - 7601
(2021/09/22)
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- Site-Selective Chemoenzymatic Modification on the Core Fucose of an Antibody Enhances Its FcγReceptor Affinity and ADCC Activity
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Fc glycosylation profoundly impacts the effector functions of antibodies and often dictates an antibody's pro- or anti-inflammatory activities. It is well established that core fucosylation of the Fc domain N-glycans of an antibody significantly reduces i
- Li, Chao,Chong, Gene,Zong, Guanghui,Knorr, David A.,Bournazos, Stylianos,Aytenfisu, Asaminew Haile,Henry, Grace K.,Ravetch, Jeffrey V.,Mackerell, Alexander D.,Wang, Lai-Xi
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p. 7828 - 7838
(2021/05/26)
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- Isolation and characterization of triterpenoid saponins from leaves of Aralia nudicaulis L
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Three new oleanolic glycosides (1–3), along with seven known saponins from various plants (4–10) were isolated for the first time from the leaves of Aralia nudicaulis. Their structures were elucidated on the basis of spectroscopic evidence, including 1D and 2D NMR, and HRESIMS. Nudicauloside A and B (1–2) have shown moderate anti-inflammatory activity, as demonstrated by inhibition of LPS-induced NO production in raw 264.7 murine macrophages (IC50 = 74–101 μM).
- Lavoie, Serge,Pierra, Julie,Legault, Jean,Raminoson, Diamondra,Lion, Quentin,Mshvildadze, Vakhtang,Pichette, André
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p. 184 - 189
(2021/04/23)
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- Design, synthesis and biological evaluation of carbohydrate-based sulphonamide derivatives as topical antiglaucoma agents through selective inhibition of carbonic anhydrase II
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A series of new carbohydrate-based sulphonamide derivatives were designed, synthesised by employing the so-call ‘sugar-tail’ approach. The compounds were evaluated in vitro against a panel of CAs. Compared to their parent compound p-sulfamoylbenzoic acid, these compounds showed nearly 100-fold improvement in their binding affinities against hCA II in vitro. All of compounds showed great water solubility and the pH value of their water solutions of compounds is 7.0. Such properties are advantageous to make them much less irritating to the eye when applied topical glaucomatous drugs, compared to the relatively highly acidic dorzolamide preparations (pH 5.5). Notably, compounds 7d, 7 g, 7 h demonstrated to topically lower intraocular pressure (IOP) in glaucomatous animals better than brinzolamide when applied as a 1% solution directly into the eye. Low cytotoxicity on human cornea epithelial cell was observed in the tested concentrations by the MTT assay.
- Fan, Zhanfang,Guo, Chun,Hou, Zhuang,Li, Chuanchao,Lin, Bin,Liu, Yang,Liu, Yichuang,Wang, Yitong,Zhang, Miao
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p. 383 - 390
(2019/12/30)
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- Non-naturally Occurring Regio Isomer of Lysophosphatidylserine Exhibits Potent Agonistic Activity toward G Protein-Coupled Receptors
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Lysophosphatidylserine (LysoPS), an endogenous ligand of G protein-coupled receptors, consists of l-serine, glycerol, and fatty acid moieties connected by phosphodiester and ester linkages, respectively. An ester linkage of phosphatidylserine can be hydrolyzed at the 1-position or at the 2-position to give 2-acyl lysophospholipid or 1-acyl lysophospholipid, respectively. 2-Acyl lysophospholipid is in nonenzymatic equilibrium with 1-acyl lysophospholipid in vivo. On the other hand, 3-acyl lysophospholipid is not found, at least in mammals, raising the question of whether the reason for this might be that the 3-acyl isomer lacks the biological activities of the other isomers. Here, to test this idea, we designed and synthesized a series of new 3-acyl lysophospholipids. Structure-activity relationship studies of more than 100 "glycol surrogate"derivatives led to the identification of potent and selective agonists for LysoPS receptors GPR34 and P2Y10. Thus, the non-natural 3-acyl compounds are indeed active and appear to be biologically orthogonal with respect to the physiologically relevant 1-and 2-acyl lysophospholipids.
- Nakamura, Sho,Sayama, Misa,Uwamizu, Akiharu,Jung, Sejin,Ikubo, Masaya,Otani, Yuko,Kano, Kuniyuki,Omi, Jumpei,Inoue, Asuka,Aoki, Junken,Ohwada, Tomohiko
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p. 9990 - 10029
(2020/10/18)
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- Synthesis of xylal- and arabinal-based crown ethers and their application as asymmetric phase transfer catalysts
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New xylal- and arabinal-based monoaza-15-crown-5 ethers were synthesized starting from l- and d-xylose, and l- and d-arabinose, respectively. These monosaccharide-based chiral macrocycles were tested as phase transfer catalysts in a few asymmetric reactions. The xylal-based crown compounds proved to be efficient catalysts in a few liquid-liquid phase reactions. The epoxidation of trans-chalcone and the Darzens condensation of α-chloroacetophenone with benzaldehyde took place with complete diastereoselectivity and up to 77% ee and 58% ee, respectively. It was found that the substituents in the aromatic ring of the chalcone and the α-chloroacetophenone had an influence on the enantioselectivity. The highest ee values were obtained in the epoxidation of 4-chlorochalcone (81% ee) and in the reaction of a 2-naphthyl analogue (96% ee), while in the Darzens condensation of 4-phenyl-α-chloroacetophenone with benzaldehyde, a maximum ee of 91% was detected. The configuration of the monosaccharide unit in the crown ring influenced the absolute configuration of the epoxyketones synthesized.
- Nemcsok, Tamás,Rapi, Zsolt,Bagi, Péter,Keglevich, Gy?rgy,Bakó, Péter
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p. 107 - 119
(2019/11/16)
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- Studies on the stereoselective synthesis and immunosuppressive activity of dihydroartemisinin-O-glycoside derivatives
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Eight new dihydroartemisinin-O-glycosides were synthesized with their relative configurations were determined based on NMR spectrum. In vitro immunosuppressive assay showed that 10α-dihydroartemisinin-β-O-D-mannoside (19a) demonstrate 88percent inhibition towards T cells proliferation and 98percent reduction in IFN-γ levels in cell media. These results suggest that dihydroartemisinin-O-glycoside as a potential lead for further in vivo evaluation.
- Bian, Hongzhu,Dong, Xun,Shen, Zhengwu,Xu, Wei,Yu, Jingfeng,Yu, Yu,Zhang, Jinghua,Zou, Xiaosu
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supporting information
(2020/07/21)
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- BIARYL AMIDES WITH MODIFIED SUGAR GROUPS FOR TREATMENT OF DISEASES ASSOCIATED WITH HEAT SHOCK PROTEIN PATHWAY
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Provided are biaryl amides and coumarin-based compounds with modified sugar groups for treatment of diseases associated with heat shock protein pathway. The compounds having the following formulas, wherein variables are as defined herein. Formulae (I), (II), (III), (IV), and (V), Pharmaceutical compositions of the compounds are also provided. These biaryl amides and coumarin-based derivatives with modified sugar groups are useful for treatment and prevention of diseases and disorders, including neurological disorders, such as neurodegenerative diseases and nerve damaging disorders, for example, diabetic peripheral neuropathy.
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Page/Page column 174; 246
(2019/12/04)
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- Design, synthesis of oleanolic acid-saccharide conjugates using click chemistry methodology and study of their anti-influenza activity
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The development of entry inhibitors is an emerging approach to the inhibition of influenza virus. In our previous research, oleanolic acid (OA) was discovered as a mild influenza hemagglutinin (HA) inhibitor. Herein, as a further study, we report the preparation of a series of OA-saccharide conjugates via the CuAAC reaction, and the anti-influenza activity of these compounds was evaluated in vitro. Among them, compound 11b, an OA-glucose conjugate, showed a significantly increased anti-influenza activity with an IC50 of 5.47 μM, and no obvious cytotoxic effect on MDCK cells was observed at 100 μM. Hemagglutination inhibition assay and docking experiment indicated that 11b might interfere with influenza virus infection by acting on HA protein. Broad-spectrum anti-influenza experiments showed 11b to be robustly potent against 5 different strains, including influenza A and B viruses, with IC50 values at the low-micromole level. Overall, this finding further extends the utility of OA-saccharide conjugates in anti-influenza virus drug design.
- Su, Yangqing,Meng, Lingkuan,Sun, Jiaqi,Li, Weijia,Shao, Liang,Chen, Kexuan,Zhou, Demin,Yang, Fan,Yu, Fei
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- Monosaccharide Analogues of Anticancer Peptide R-Lycosin-I: Role of Monosaccharide Conjugation in Complexation and the Potential of Lung Cancer Targeting and Therapy
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Glycoconjugation is a promising modification strategy for the optimization of peptide drugs. In this study, five different monosaccharide derivatives (7a-e) were covalently linked to the N-terminal of R-lycosin-I, which yielded five glycopeptides (8a-e). They demonstrated increased or reduced cytotoxicity depending on monosaccharide types, which might be explained by the changes of physicochemical properties. Among all synthesized glycopeptides, only 8a exhibited increased cytotoxicity (IC50 = 9.6 ± 0.3 μM) and selectivity (IC50 = 37.4 ± 5.9 μM). The glucose transporter 1 (GLUT1) with high expression in cancer cells was approved to be involved in the cytotoxicity and selectivity enhancement of 8a. Furthermore, 8a but not R-lycosin-I inhibited tumor growth in the nude mice xenograft model without generating side effects intraperitoneally. Taken together, this study reveals the different monosaccharide roles in peptide modification and also provides an optimized anticancer peptide with high activity and selectivity, that is, 8a might be a promising lead for developing anticancer drugs.
- Zhang, Peng,Ma, Jing,Zhang, Qianqian,Jian, Shandong,Sun, Xiaoliang,Liu, Bobo,Nie, Liqin,Liu, Meiyan,Liang, Songping,Zeng, Youlin,Liu, Zhonghua
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p. 7857 - 7873
(2019/10/11)
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- Phosphotungstic acid as a novel acidic catalyst for carbohydrate protection and glycosylation
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This work demonstrates the utilization of phosphotungstic acid (PTA) as a novel acidic catalyst for carbohydrate reactions, such as per-O-acetylation, regioselective O-4,6 benzylidene acetal formation, regioselective O-4 ring-opening, and glycosylation. These reactions are basic and salient during the synthesis of carbohydrate-based bioactive oligomers. Phosphotungstic acid's high acidity and eco-friendly character make it a tempting alternative to corrosive homogeneous acids. The various homogenous acid catalysts were replaced by the phosphotungstic acid solely for different carbohydrate reactions. It can be widely used as a catalyst for organic reactions as it is thermally stable and easy to handle. In our work, the reactions are operated smoothly under ambient conditions; the temperature varies from 0 °C to room temperature. Good to excellent yields were obtained in all four kinds of reactions.
- Chen, Jyun-Siao,Sankar, Arumugam,Lin, Yi-Jyun,Huang, Po-Hsun,Liao, Chih-Hsiang,Wu, Shen-Shen,Wu, Hsin-Ru,Luo, Shun-Yuan
-
p. 33853 - 33862
(2019/11/11)
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- Ni-Catalyzed Suzuki-Miyaura Cross-Coupling of α-Oxo-vinylsulfones to Prepare C-Aryl Glycals and Acyclic Vinyl Ethers
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We demonstrate that readily available and bench-stable α-oxo-vinylsulfones are competent electrophiles in Ni-catalyzed Suzuki-Miyaura cross-coupling reactions. The C-sulfone bond in the α-oxo-vinylsulfone motif is cleaved chemoselectively in these reactions, furnishing C-aryl glycals or acyclic vinyl ethers in high yields. These reactions proceed under mild conditions and tolerate a remarkable scope of heterocycles and functional groups. Preliminary mechanistic studies revealed the importance of an α-heteroatom in facilitating these transformations.
- Gong, Liang,Sun, Hong-Bao,Deng, Li-Fan,Zhang, Xia,Liu, Jie,Yang, Shengyong,Niu, Dawen
-
supporting information
(2019/05/22)
-
- Ni-Catalyzed Suzuki-Miyaura Cross-Coupling of α-Oxo-vinylsulfones to Prepare C-Aryl Glycals and Acyclic Vinyl Ethers
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We demonstrate that readily available and bench-stable α-oxo-vinylsulfones are competent electrophiles in Ni-catalyzed Suzuki-Miyaura cross-coupling reactions. The C-sulfone bond in the α-oxo-vinylsulfone motif is cleaved chemoselectively in these reactions, furnishing C-aryl glycals or acyclic vinyl ethers in high yields. These reactions proceed under mild conditions and tolerate a remarkable scope of heterocycles and functional groups. Preliminary mechanistic studies revealed the importance of an α-heteroatom in facilitating these transformations.
- Gong, Liang,Sun, Hong-Bao,Deng, Li-Fan,Zhang, Xia,Liu, Jie,Yang, Shengyong,Niu, Dawen
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supporting information
p. 7680 - 7686
(2019/05/22)
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- MULTIBIOTIC AGENTS AND METHODS OF USING THE SAME
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Multibiotic agents are disclosed. The multibiotic agents may contain two or more moieties linked through bonds cleavable in vivo. The bonds cleavable in vivo can be ester bonds, amide bonds, azo bonds, glycosidic bonds, carbonate linkers, or carbamate linkers. The moieties can be alcohol cores, amine cores, and/or acyls. Also disclosed are compositions containing multibiotic agents and methods of using the multibiotic agents.
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Page/Page column 137; 138
(2019/01/06)
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- Synthesis of C3-Neoglycosides of digoxigenin and their anticancer activities
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Cardiac glycosides exhibit significant anticancer effects and the glycosyl substitution at C3 position of digoxigenin is pivotal for their biological activity. In order to study the structure-activity relationship (SAR) of cardiac glycosides toward cancers and explore more potent anticancer agents, a series of C3-O-neoglycosides and C3-MeON-neoglycosides of digoxigenin were synthesized by the Koenigs-Knorr and neoglycosylation method, respectively. In addition, digoxigenin bisdigitoxoside and monodigitoxoside were prepared from digoxin by sodium periodate (NaIO4) oxidation and 6-aminocaproic acid hydrolysis. The SAR analysis revealed that C3-O-neoglycosides of digoxigenin exhibited stronger cytotoxicity and induction of Nur77 expression of tumor cells than C3-MeON-neoglycosides. Also, 3β-O-glycosides exhibited stronger anticancer effects than 3α-O-glycosides. Among them, 3β-O-(β-L-fucopyranosyl)-digoxigenin (3i) showed the highest activity on induction of Nur77 expression and translocation from the nucleus to cytoplasm, leading to cancer cell apoptosis.
- Li, Xiao-san,Ren, Yi-chang,Bao, Yu-zhou,Liu, Jie,Zhang, Xiao-kun,Zhang, You-wei,Sun, Xue-Long,Yao, Xin-sheng,Tang, Jin-Shan
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supporting information
p. 252 - 262
(2018/01/12)
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- ANTICANCER COMPOUNDS
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The present invention discloses compounds for inhibition of uncontrolled cell proliferation particularly in cancer stem cells. Particularly, the invention relates to compounds of Formula III to XIV for the treatment of cancer, such as breast and prostate cancer.
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Page/Page column 58; 59
(2018/11/22)
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- THERAPEUTIC COMPOUNDS
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The invention provides compounds of formula (I): and salts thereof, wherein R1, R2, R3, B, X, Y, and Z have any of the values defined herein. The invention also provides pharmaceutical compositions comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof, processes for preparing compounds of formula (I) and salts thereof, intermediates useful for preparing compounds of formula (I) and salts thereof, and therapeutic methods for treating cancer using a compound of formula (I) or a pharmaceutically acceptable salt thereof.
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Page/Page column 20; 21
(2017/06/30)
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- Stereoselective acetylation of hemicellulosic C5-sugars
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The stereoselective peracetylation of α-D-xylose (1) and α-L-arabinose (4) using a combination of triethylamine and acetic anhydride in the presence or absence of a catalytic amount of dimethylaminopyridine (DMAP) is described. The peracetylated D-xylose and L-arabinose alpha pyranose anomers 2α and 5α are obtained in 97% and 56% yields respectively. The peracetylated D-xylose beta pyranose anomer 2β is obtained in 71% yield through simple modification of the reaction conditions. Details regarding synthesis and isolation optimization studies under different conditions are presented below. The stereoselective peracetylation reactions disclosed here have been used to separate mixtures of D-xylose and L-arabinose as their peracetylated derivatives 2β and 5α in 47% and 42% yields and can provide pure pentoses after deacetylation.
- Herde, Zachary D.,John, Prathap D.,Alvarez-Fonseca, Dania,Satyavolu, Jagannadh,Burns, Christopher T.
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-
- Sequential Dy(OTf)3-Catalyzed Solvent-Free Per-O-Acetylation and Regioselective Anomeric De-O-Acetylation of Carbohydrates
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Dysprosium(III) trifluoromethanesulfonate-catalyzed per-O-acetylation and regioselective anomeric de-O-acetylation of carbohydrates can be tuned by adjusting the reaction medium. In this study, the per-O-acetylation of unprotected sugars by using a near-stoichiometric amount of acetic anhydride under solvent-free conditions resulted in the exclusive formation of acetylated saccharides as anomeric mixtures, whereas anomeric de-O-acetylation in methanol resulted in a moderate-to-excellent yield. Reactions with various unprotected monosaccharides or disaccharides followed by a semi-one-pot sequential conversion into the corresponding acetylated glycosyl hemiacetal also resulted in high yields. Furthermore, the obtained hemiacetals could be successfully transformed into trichloroimidates after Dy(OTf)3-catalyzed glycosylation.
- Yan, Yi-Ling,Guo, Jiun-Rung,Liang, Chien-Fu
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p. 2471 - 2479
(2017/09/06)
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- A kind of mountain Lotus leaf derivative and its preparation and use
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The invention provides a kind of diphyllin derivatives, and a preparation method and application thereof. The related diphyllin derivatives have the chemical structural general formula shown as formula A in the specification. The invention discloses the structural general formula of the above compounds, a synthetic method, application as a bactericide, a plant virus resistant agent and a plant activating agent, and a processing technology of mixing the above compounds with an agriculturally-acceptable assistant or synergist for preparing the bactericide, the plant virus resistant agent and the plant activating agent. The invention also discloses application of combinations of the compounds and commercial bactericides, plant virus resistant agents and plant activating agents to control agricultural, forestry and garden diseases, insect attack, mite attack, virus attack and the like, and a preparation method. The invention also discloses application of the above compounds to prepare medicines and auxiliary medicines for treating cancers and immune imbalance, and application of the combinations of the above compounds.
- -
-
Paragraph 0020; 0067-0069
(2018/02/04)
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- Efficient and selective N-, S- and O-acetylation in TEAA ionic liquid as green solvent. Applications in synthetic carbohydrate chemistry
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Background: The ionic liquid triethylammonium acetate (TEAA) was found to be an efficient solvent in the acetylation of alcohols, amines, oximes and thiols to their corresponding acetyl compounds using only a 10% excess of acetic anhydride under mild conditions. Moreover TEAA is not only an inexpensive and recyclable solvent but also an anomeric selective catalyst in the per-O-acetylation of sugar moieties. Methods: Simple and effective organic synthesis protocols were provided for the selective acetylation of several substrates. The products were fully characterized by 1H and 13C NMR spectroscopy and the anomeric ratios were obtained from the 1H spectra. Results: Structurally diverse alcohols, phenols, thiols, amines, carbohydrates and oximes underwent acylation under mild conditions by this procedure to provide the corresponding acetates in excellent yields. TEAA ionic liquid is unique in its capability to act as both, solvent and high selective catalyst. As expected, the reaction proceeds with high b anomeric selectivity for sugars derivatives. Moreover, the ionic liquid was regenerated, recycled and reused for three times without apparent loss of reactivity and selectivity in all cases. Conclusions: The present procedure provides a powerful and versatile acylation method for alcohols, phenols, thiols, amines, oximes and carbohydrates. This protocol is endowed with several unique merits: selectivity, cost-efficiency, atom-economy and mild reaction conditions tolerable to acid sensitive functionalities. With these features, this method may be considered as a better alternative for the acetylation of a wide range of substrates.
- Lafuente, Leticia,Díaz, Gisela,Bravo, Rodolfo,Ponzinibbio, Agustín
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p. 195 - 200
(2016/02/26)
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- Synthesis and Biological Evaluation of Novel Carbohydrate-Derived Derivatives of Erlotinib
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(Table presented.). A series of novel carbohydrate-derived Erlotinib derivatives were prepared by the copper-catalyzed cycloaddition reaction of erlotinib with various azido-sugars. The structures of the newly synthesized compounds were characterized and their cytostatic effects evaluated in vitro on human cancer cell lines MDA-MB-231, HEPG-2, A549, and MCF-7 using an MTS assay. The novel erlotinib derivatives had the expected inhibitory effects on MDA-MB-231 and HEPG-2 cell llines. Among the compounds evaluated the carbohydrate-derived compounds 5b, 5d, 6a, and 6c had more potent activities against MDA-MB-231 or HEPG-2 than Erlotinib. Drug Dev Res, 2016.
- Yu, Wenbo,Jiang, Luxia,Shen, Chao,Zhang, Pengfei
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p. 319 - 325
(2016/10/12)
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- Synthesis of Functionalized 2-(4-Hydroxyphenyl)-3-methylbenzofuran Allosteric Modulators of Hsp90 Activity
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Hsp90 is a molecular chaperone that plays a pivotal role in the cell life cycle. ATP-regulated internal dynamics are critical to Hsp90 function and we recently demonstrated that these dynamics can be modulated in an allosteric fashion; the protein C-terminal domain (CTD) can be effectively targeted with a family of 2-phenyl-benzofuran derivatives. Here we describe the expansion of the initial library, reporting 28 new derivatives that explore the chemical space at opposite ends of the benzofuran scaffold. Interactions of the compounds with a full-length protein homolog were explored by Saturation Transfer Difference (STD) NMR spectroscopy. In this context we also report the interaction epitope of Novobiocin, a known CTD inhibitor.
- Sattin, Sara,Panza, Matteo,Vasile, Francesca,Berni, Francesca,Goti, Giulio,Tao, Jiahui,Moroni, Elisabetta,Agard, David,Colombo, Giorgio,Bernardi, Anna
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p. 3349 - 3364
(2016/07/26)
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- Organoboron-Promoted Regioselective Glycosylations in the Synthesis of a Saponin-Derived Pentasaccharide from Spergularia ramosa
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Organoboron-mediated regioselective glycosylations were employed as key steps in the total synthesis of a branched pentasaccharide from a saponin natural product. The ability to use organoboron activation to differentiate OH groups in an unprotected glycosyl acceptor, followed by substrate-controlled reactions of the obtained disaccharide, enabled a streamlining of the synthesis relative to a protective group-based approach. This study revealed a matching/mismatching effect of the relative configuration of donor and acceptor on the efficiency of a regioselective glycosylation reaction, a problem that was solved through the development of a novel boronic acid-amine copromoter system for glycosyl acceptor activation.
- Mancini, Ross S.,McClary, Corey A.,Anthonipillai, Stefi,Taylor, Mark S.
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p. 8501 - 8510
(2015/09/15)
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- ARYLNAPHTHALENE LACTONE DERIVATIVES AND METHODS OF MAKING AND USING THEREOF
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A series of natural products including phyllanthusum, an arylnaphthalene lignan derivative, with anticancer and antitumor and immurtostimulating activity are disclosed. The invention further encompasses methods of adding water solubilizing groups to the arylrings that include phosphonyl groups.
- -
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- Cu(ClO4)2·6H2O catalyzed solvent free per-O-acetylation and sequential one-pot conversions of sugars to thioglycosides
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The solvent free per-O-acetylation of various reducing and non-reducing sugars has been carried out using stoichiometric amounts of acetic anhydride and copper(ii) perchlorate hexahydrate as the catalyst. The reactions with various reducing monosaccharides have also been followed by a one-pot sequential conversion to the corresponding thioglycosides in high yields. This journal is
- Chatterjee, Debnath,Paul, Abhijit,Rajkamal,Yadav, Somnath
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p. 29669 - 29674
(2015/05/20)
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- I2/ionic liquid as a highly efficient catalyst for per-O-acetylation of sugar under microwave irradiation
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A practical and highly efficient approach was developed to synthesize peracetylated sugar derivatives using a recyclable iodine/PEG400-based ionic liquid catalyst (I2/IL). The peracetylated sugars were readily obtained in a few minutes in excellent yields (90%-99%, 13 examples) on a multi-gram scale (50.0 mmol) by the reaction of sugar and acetic anhydride under microwave irradiation in the absence of a volatile organic solvent. The desired product was easily obtained by simple extraction with toluene from the reaction mixture, and I2/ILs can be readily recovered and reused at least six times without obvious loss in the yield. When the scale of the per-O-acetylation reaction was increased to 50.0 mmol, the desired product was still obtained in 90% yield after five recycles.
- Xiong, Xingquan,Yi, Chao,Han, Qian,Shi, Lin,Li, Sizhong
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p. 237 - 243
(2015/09/28)
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- 1 -(CYCLOPENT-2-EN-1 -YL)-3-(2-HYDROXY-3-(ARYLSULFONYL)PHENYL)UREA DERIVATIVES AS CXCR2 INHIBITORS
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The invention relates to 1-(3-sulfonylphenyl)-3-(cyclopent-2-en-1-yl)urea derivatives, and their use in treating or preventing diseases and conditions mediated by the CXCR2 receptor. In addition, the invention relates to compositions containing the derivatives and processes for their preparation.
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Page/Page column 85
(2015/12/18)
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- Exploration of the active site of β4GalT7: Modifications of the aglycon of aromatic xylosides
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Proteoglycans (PGs) are macromolecules that consist of long linear polysaccharides, glycosaminoglycan (GAG) chains, covalently attached to a core protein by the carbohydrate xylose. The biosynthesis of GAG chains is initiated by xylosylation of the core protein followed by galactosylation by the galactosyltransferase β4GalT7. Some β-d-xylosides, such as 2-naphthyl β-d-xylopyranoside, can induce GAG synthesis by serving as acceptor substrates for β4GalT7 and by that also compete with the GAG synthesis on core proteins. Here we present structure-activity relationships for β4GalT7 and xylosides with modifications of the aromatic aglycon, using enzymatic assays, cell studies, and molecular docking simulations. The results show that the aglycons reside on the outside of the active site of the enzyme and that quite bulky aglycons are accepted. By separating the aromatic aglycon from the xylose moiety by linkers, a trend towards increased galactosylation with increased linker length is observed. The galactosylation is influenced by the identity and position of substituents in the aromatic framework, and generally, only xylosides with β-glycosidic linkages function as good substrates for β4GalT7. We also show that the galactosylation ability of a xyloside is increased by replacing the anomeric oxygen with sulfur, but decreased by replacing it with carbon. Finally, we propose that reaction kinetics of galactosylation by β4GalT7 is dependent on subtle differences in orientation of the xylose moiety. This journal is
- Siegbahn, Anna,Thorsheim, Karin,St?hle, Jonas,Manner, Sophie,Hamark, Christoffer,Persson, Andrea,Tykesson, Emil,Mani, Katrin,Westergren-Thorsson, Gunilla,Widmalm, G?ran,Ellervik, Ulf
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p. 3351 - 3362
(2015/03/18)
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- In(III) triflate-mediated solvent-free synthesis and activation of thioglycosides by ball milling and structural analysis of long chain alkyl thioglycosides by TEM and quantum chemical methods
-
Conventional solution-phase synthesis of thioglycosides from glycosyl acetates and thiols in the presence of In(III) triflate as reported for benzyl thioglucoside failed when applied to the synthesis of phenolic and alkyl thioglycosides. But, it was achieved in high efficiency and diastereospecificity with ease by solvent-free grinding in a ball mill. The acetates in turn were also obtained by the homogenization of free sugars with stoichiometric amounts of acetic anhydride and catalytic In(OTf)3 in the mill as neat products. Per-O-benzylated thioglycosides on grinding with an acceptor sugar in the presence of In(OTf)3 yield the corresponding O-glycosides efficiently. The latter in the case of a difficult secondary alcohol was nearly exclusive (>98%) in 1,2-cis-selectivity. In contrast, the conventional methods for this purpose require use of a coreagent such as NIS along with the Lewis acid to help generate the electrophilic species that actually is responsible for the activation of the thioglycoside donor in situ. The distinctly different self-assembling features of the peracetylated octadecyl 1-thio-α- and β-d-galactopyranosides observed by TEM could be rationalized by molecular modeling.
- Kumar, Vajinder,Taxak, Nikhil,Jangir, Ramniwas,Bharatam, Prasad V.,Kartha, K. P. Ravindranathan
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p. 3427 - 3439
(2014/05/06)
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- Carbohydrate-derived iminium salt organocatalysts for the asymmetric epoxidation of alkenes
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A new family of carbohydrate-based dihydroisoquinolinium salts has been prepared and tested for potential as asymmetric catalysts for the epoxidation of unfunctionalized alkene substrates, providing up to 57% ee in the product epoxides.
- Bulman Page, Philip C.,Chan, Yohan,Liddle, John,Elsegood, Mark R.J.
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p. 7283 - 7305
(2017/09/13)
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- Sulfonic acid functionalized nano γ-Al2O3 catalyzed per-O-acetylated of carbohydrates
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A simple and clean synthesis of per-O-acetylation carbohydrate derivatives has been accomplished by treatment of sugars with a stoichiometric quantity of acetic anhydride under solvent-free conditions in the presence of sulfonic acid functionalized nano γ-Al2O3 as an efficient and environmentally benign catalyst.
- Wu, Liqiang,Yin, Zhikui
-
-
- Cyclometalated gold(III) iminophosphoranes which incorporate carbohydrate groups
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Iminophosphoranes with organic groups derived from d-glucose, d-galactose and l-arabinose have been used to prepare gold(III) dichloride complexes via mercurated intermediates, since direct cyclometallation was unsuccessful. Structures and full spectroscopic data are reported. Replacement of one or more of the chloride ligands by PPh3, or by thiosalicylate gave new derivatives. Biological screening showed no enhanced activity relative to other alkyl or aryl analogues.
- Jarman, Bevan P.,Nicholson, Brian K.
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scheme or table
p. 1 - 9
(2012/03/12)
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- A facile and efficient method for the one-pot synthesis of per-O-acetylated thioglycosides from unprotected sugars
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An efficient, convenient protocol for the preparation of per-O-acetylated p-tolylthio glycosides is described. Treatment of various unprotected sugars, including 2-deoxy-2-amino sugars, sialic acid, lactose, and maltose, with acetic anhydride using SnCl4 as a catalyst, and subsequently with p-tolylthiol, furnished the corresponding thioglycosides in 71%-90% yield under solvent-free conditions.
- Yan, Shiqiang,Ding, Ning,Zhang, Wei,Wang, Peng,Li, Yingxia,Li, Ming
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p. 571 - 583
(2012/10/30)
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- Synthesis of 1,2,3-triazoles from xylosyl and 5-thioxylosyl azides: Evaluation of the xylose scaffold for the design of potential glycogen phosphorylase inhibitors
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Various acetylenic derivatives and acetylated β-d-xylopyranosyl azide or the 5-thio-β-d-xylopyranosyl analogue were coupled by Cu(I)-catalyzed azide alkyne 1,3-dipolar cycloaddition (CuAAC) to afford a series of 1-xylosyl-4-substituted 1,2,3-triazoles. Controlled oxidation of the endocyclic sulfur atom of the 5-thioxylose moiety led to the corresponding sulfoxides and sulfones. Deacetylation afforded 19 hydroxylated xylose and 5-thioxylose derivatives, found to be only sparingly water-soluble. Compared to glucose-based analogues, they appeared to be much weaker inhibitors of glycogen phosphorylase, as the absence of a hydroxymethyl group weakens their binding at the enzyme active site. However, such new xylose derivatives might be useful glycomimetics.
- Goyard, David,Baron, Marc,Skourti, Paraskevi V.,Chajistamatiou, Aikaterini S.,Docsa, Tibor,Gergely, Pál,Chrysina, Evangelia D.,Praly, Jean-Pierre,Vidal, Sébastien
-
-
- Serine and threonine Schiff base esters react with β-anomeric peracetates in the presence of BF3·Et2O to produce β-glycosides
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Improved procedures are reported for the glycosylation of L-serine and L-threonine utilizing activated Schiff base glycosyl acceptors, which are less expensive and more efficient alternatives to published methods. L-serine or L-threonine benzyl ester hydrochloride salts were reacted with the diarylketimine bis-(4-methoxyphenyl)-methanimine in CH3CN at rt to form the more nucleophilic Schiff bases 3a and 3b in excellent yield. These Schiff bases exhibited ring-chain tautomerism in CDCl3 as shown by 1H NMR. Schiff bases 3a and 3b, acting as glycosyl acceptors, reacted at rt with simple sugar peracetate donors with BF3·OEt 2 promotion to provide the corresponding L-serine and L-threonine O-linked glycosides in excellent yields and purities. The dipeptide ester Schiff base Ar2C = N-Ser-Val-OCH3 3e also reacted to provide β-glycosides in excellent yields, and without epimerization. With microwave irradiation the reactions were complete in 2 to 5 min. To investigate this reaction further, classical AgOTf-promoted Koenigs-Knorr reaction of D-glucopyranosyl, lactosyl, and maltosyl bromides were examined, providing the β-glycosides with yields ranging from 35% to 68%. The difference in reactivity between α- and β-carbohydrate peracetate donors was remarkable. The less configurationally stable D-xylopyranosyl tetra-acetate (a pentose) showed no selectivity (αvsβ-configuration) toward the Schiff bases. Copyright Taylor & Francis Group, LLC.
- Keyari, Charles M.,Polt, Robin
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scheme or table
p. 181 - 206
(2011/04/23)
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- Novel olefin-phosphorus hybrid and diene ligands derived from carbohydrates
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Starting from readily available monosaccharides d-glucose and d-arabinose, a family of novel chiral diene and olefin-phosphinite hybrid ligands has been designed. These ligands were prepared by attaching phosphinite or allylic donor sites onto unsaturated carbohydrate scaffolds. In rhodium(I)-catalysed conjugate addition of boronic acids to enones, the olefin-phosphinite hybrids gave products in up to 99% ee and above, whereas the dienes only led to modest enantioselectivity. However, by shifting the allylic donor sites from position 4 of the pyranose to the anomeric centre, an unexpected reversal of the stereoinduction process was observed. Georg Thieme Verlag Stuttgart New York.
- Grugel, Holger,Minuth, Tobias,Boysen, Mike M. K.
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experimental part
p. 3248 - 3258
(2010/11/18)
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