- Rapid synthesis of 1-deoxygalactonojirimycin using a carbamate annulation
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A remarkably efficient synthesis of the biologically important iminosugar 1-deoxygalactonojirimycin (DGJ) is presented. Key to this strategy is the development of a novel carbamate annulation reaction that favours formation of a six-membered carbamate-containing piperidine skeleton over its five-membered counterpart.
- Timmer, Mattie S.M.,Dangerfield, Emma M.,Cheng, Janice M.H.,Gulab, Shivali A.,Stocker, Bridget L.
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- Covalent Lectin Inhibition and Application in Bacterial Biofilm Imaging
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Biofilm formation by pathogenic bacteria is a hallmark of chronic infections. In many cases, lectins play key roles in establishing biofilms. The pathogen Pseudomonas aeruginosa often exhibiting various drug resistances employs its lectins LecA and LecB as virulence factors and biofilm building blocks. Therefore, inhibition of the function of these proteins is thought to have potential in developing “pathoblockers” preventing biofilm formation and virulence. A covalent lectin inhibitor specific to a carbohydrate binding site is described for the first time. Its application in the LecA-specific in vitro imaging of biofilms formed by P. aeruginosa is also reported.
- Wagner, Stefanie,Hauck, Dirk,Hoffmann, Michael,Sommer, Roman,Joachim, Ines,Müller, Rolf,Imberty, Anne,Varrot, Annabelle,Titz, Alexander
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- Hypervalent iodine system for debenzylation of sugars
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A simple and mild system using 4,4′-bis-(dichloroiodo)-biphenyl in combination with tetraethylammonium bromide (TEAB) at room temperature has been developed for selective debenzylation of sugars. Acetates, benzoate, and sensitive glycosidic linkages are unaffected. Copyright Taylor & Francis Group, LLC.
- Telvekar, Vikas N.
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- Thermoresponsive copolymers with pendant d-galactosyl 1,2,3-triazole groups: Synthesis, characterization and thermal behavior
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A galactose containing glycomonomer has been synthesized by copper catalyzed azide-alkyne cyclo-addition reaction (CuAAC) of 6-azido-6-deoxy-1,2:3,4-di-O-isopropylidene-α-d-galactopyranose with propargyl acrylate. This monomer was subjected to homopolymerization and copolymerization with N-isopropylacrylamide (NIPAm) at different compositions by free radical polymerization using 2,2′-azobis-isobutyronitrile (AIBN) as an initiator. The composition of the copolymer was determined by 1H-NMR spectroscopy. Upon acid hydrolysis of acetonide protected polymers, water-soluble deprotected polymers were obtained. The polymers were characterized and confirmed by NMR, IR, GPC and thermal analytical techniques. The protected and deprotected copolymers showed a sharp cloud-point temperature and a linear correlation was obtained between the lower critical solution temperatures (LCST) and the concentration of glycomonomer in the copolymers. This allows tuning the thermal response by simply altering the copolymer composition. Water contact angle experiments showed the changes in the hydrophilicity of copolymers with compositions that supported the LCST results. The glass transition temperature of protected copolymers followed a regular monotonic decreasing trend with increasing glycomonomer content, whereas Tg of deprotected copolymers increased due to H-bond interaction. The attempts to develop thermoresponsive polymers having LCSTs at physiological temperature were successful.
- Dhumure, Archana B.,Patil, Ajay B.,Kulkarni, Anuja S.,Voevodina, Irina,Scandola, Mariastella,Shinde, Vaishali S.
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- Synthesis of new five membered nitrogen containing heterocycles bearing D-galactose side chains
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The synthesis of 5-[6'-deoxy-(1',2':3',4'-di-O-isopropylidene-α-D-galactopyranos-6'-yl)]tetra zole and its reaction with acetic anhydride and 1,2:3,4-di-O-isopropylidene-6-O-(4-toluenesulfonyl)-α-D-galactopyranose are described.
- Klier,Alves,Prado,De Souza Filho,D'Accorso
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- Synthesis of amphiphilic galactopyranosyl diamines and amino alcohols as antitubercular agents
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Mono- and diacylated derivatives of galactopyranosyl amines were obtained from d-galactose, via aminated intermediates prepared by reaction of 6-deoxy-6-iodo-1,2:3,4-di-O-isopropylidene-α-d-galactopyranose with 1,3-propanediamine, 1,2-ethanediamine or ethanolamine. Monoacylated derivatives displayed antitubercular activity.
- de Almeida, Mauro Vieira,Le Hyaric, Mireille,Amarante, Giovanni Wilson,Silva Lourenco, Maria Cristina,Lima Brandao, Marcelo Luiz
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- Synthesis, spectroscopic studies, and x-ray crystallographic analysis of the organotin carbohydrate: 1,2:3,4-di-O-isopropylidene-6-O-triphenylstannylmethyl-α-D-galactopyranose
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The title organotin carbohydrate, C31H36O6Sn, has been synthesized and its molecular structure has been determined in solution and in the solid state.NMR, infrared, mass and X-ray crystallographic techniques were used.The chiral molecules crystallize in the monoclinic space group P21 with Z=2.The triphenyltin and carbohydrate moieties are linked by a trans methylene-oxygen-methylene arrangement.The pyranosyl ring adopts a twist-boat conformation and the isopropylidene rings adopt different (half-chair and envelope) forms.Solution and solid-state conformations are similar as only three Δ 13C shift values are greater than 2ppm; the Δ 119Sn value is 12 ppm.KEY WORDS: X-ray crystallographic analysis; organotin; carbohydrate.
- Cox, Philip J.,Melvin, Olga A.,Garden, Simon J.,Wardell, James L.
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- Helical Self-Assembly of Optically Active Glycoconjugated Phthalocyanine J-Aggregates
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Four galactoconjugated zinc(II) phthalocyanines (Pcs) have been prepared and fully characterized. The carbohydrate-containing phthalonitrile precursors of the Pcs were synthesized through a copper-catalysed azide-alkyne cycloaddition (CuAAC). The Pcs show a remarkable aggregation behaviour in solution, depending on the nature of the solvent, the temperature and the substitution position on the phthalocyanine. Solvent-dependent CD-spectroscopy experiments show that these Pcs aggregate as chiral helices in solution. Crystal structure data of a phthalocyanine bearing two carbohydrate units substantiate the properties shown by CD spectroscopy. Furthermore, the 1,2,3-triazole moieties of the Pcs play a decisive role in the formation of supramolecular aggregates. The glycoconjugated zinc(II) phthalocyanines described here show molar extinction coefficients ?max>105 M?1 cm?1 and absorption maxima λmax>680 nm, which make them attractive photosensitizers for Photodynamic Therapy (PDT).
- B?chle, Felix,Maichle-M?ssmer, C?cilia,Ziegler, Thomas
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- Conformation of the Galactose Ring Adopted in Solution and in Crystalline Form as Determined by Experimental and DFT 1H NMR and Single-Crystal X-ray Analysis
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The solution-state conformations of various galactose derivatives were determined by comparison of the experimental 1H-1H vicinal coupling constants to those calculated using density functional theory (DFT) at the B3LYP/cc-pVTZ//B3LYP/6-31G(d,p) level of theory. The agreement between the experimental and calculated vicinal coupling constants for 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose was good, thereby confirming an OS2 skew conformation for it and its derivatives on the basis of their similar observed couplings. Single-crystal X-ray analysis of 1,2:3,4-di-O-isopropylidene-6-O-(3,4, 6-tri-O-acetyl-2-deoxy-2-N-phthalimido-β-D-glucopyranosyl) -α-D-galactopyranose and 1,2,3,4,6-penta-O-acetyl-α -D-galactopyranose provided OS2 and 4C 1 conformations, respectively, for the galactose ring in the solid state. The solid-state structures proved to be suitable starting structures for further DFT structure refinement or for immediate calculation of the coupling constants.
- Roslund, Mattias U.,Klika, Karel D.,Lehtilae, Reko L.,Taehtinen, Petri,Sillanpaeae, Reijo,Leino, Reko
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- Me3SI-promoted chemoselective deacetylation: a general and mild protocol
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A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.
- Gurawa, Aakanksha,Kashyap, Sudhir,Kumar, Manoj
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p. 19310 - 19315
(2021/06/03)
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- Epoc group: Transformable protecting group with gold(iii)-catalyzed fluorene formation
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This study presents the novel concept of a transformable protecting group, which changes its properties through structural transformation. Based on this concept, we developed a 2-(2-ethynylphenyl)-2-(5-methylfuran-2-yl)-ethoxycarbonyl (Epoc) group. The Epoc group was transformed into an Fmoc-like structure with gold(iii)-catalyzed fluorene formation and was removable under Fmoc-like mild basic conditions post-transformation even though it was originally stable under strongly basic conditions. As an application for organic synthesis, the Epoc group provides the novel orthogonality of gold(iii)-labile protecting groups in solid-phase peptide synthesis. In addition, the high turnover number of fluorene formation in aqueous media is suggestive of the applicability of the Epoc group to biological systems. This journal is
- Chang, Tsung-Che,Tanaka, Katsunori,Yamamoto, Tomoya
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p. 10703 - 10709
(2021/08/24)
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- D-galactose-based organogelator for phase-selective solvent removal and sequestration of cationic dyes
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Naturally occurring sugar-based monomers are attractive substrates in the design of functional glycopolymers. In this study, we report on the development of D-galactose based organogels of varying crosslink density capable of selective adsorption of dyes and solvents. Free radical polymerization of 6-O-methacryloyl-1,2;3,4-di-O-isopropylidene-D-galactose in the presence of nonamethylene glycoldimethacrylate generated novel crosslinked polymers OG10, OG15 and OG20 with 10, 15 and 20 wt% crosslinker, respectively. Depending on the nature of the solvent, OG10 undergoes swelling upto 935%. The negative zeta potential, as determined from DLS measurements, and the gelation ability suggested the potential utility of the polymer for dye removal from water. OG10 displayed significant adsorption of rhodamine B (RhB) (>95%), crystal violet (>93%), and methylene blue (>70%) dyes as well as the selective adsorption of >90% RhB from a solution containing both RhB and methyl orange. These porous organogels are also found to be suitable for phase-selective removal of organic solvents.
- Goel, Shubhra,Jacob, Josemon
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- Asymmetric total syntheses of naturally occurring α,β-enone-containing RALs, L-783290 and L-783277 through intramolecular base-mediated macrolactonization reaction
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Asymmetric total synthesis of two naturally occurring α,β-enone containing RALs, L-783290 and L-783277 is described in this article. An E-selective Horner-Wadsworth-Emmons (HWE) olefination was used as a key reaction to construct the C7′-C8′ olefinic unsaturation in L-783290. An enantiopure alkyne addition to the aldehyde followed by Z-selective partial reduction was employed to construct the C7′-C8′ olefinic unsaturation in L-783277. Biomimetic lactonization reaction was used to construct the macrolactone core in both the target molecules.
- Chakraborty, Joy,Ghosh, Ankan,Nanda, Samik
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p. 2331 - 2345
(2020/04/07)
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- Stereoselective Phenylselenoglycosylation of Glycals Bearing a Fused Carbonate Moiety toward the Synthesis of 2-Deoxy-β-galactosides and β-Mannosides
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A phenylselenoglycosylation reaction of glycal derivatives mediated by diphenyl diselenide and phenyliodine(III) bis(trifluoroacetate) under mild conditions is described. Stereoselective glycosylation has been achieved by installing fused carbonate on those glycals. 3,4-O-Carbonate galactals and 2,3-O-carbonate 2-hydroxyglucals are converted into corresponding glycosides in good yields with excellent β-selectivity, resulting in 2-phenylseleno-2-deoxy-β-galactosides and 2-phenylseleno-β-mannosides which are good precursors of 2-deoxy-β-galactosides and β-mannosides, respectively.
- Li, Zhongjun,Meng, Shuai,Yao, Wang,Zhong, Wenhe
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supporting information
(2020/04/09)
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- Synthesis and applications of carbohydrate based chiral ionic liquids as chiral recognition agents and organocatalysts
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Chiral ionic liquids (CILs) have shown a wide range of applications in variety of domains in chemistry. Because of this, synthesis and applications of CILs have always been areas of interest for research in the last 20 years. Present work describes, the synthesis of six carbohydrate based chiral ionic liquids (CCILs) by following simple procedures and their applications. Structures of the CCILs were confirmed through various analytical techniques like NMR spectroscopy (1H, 13C, 11B, 31P, 19F), EI-MS, and polarimetry. Designed CCILs were tested as chiral recognising agents using sodium salt of Mosher's acid as model substrate through 19F NMR spectroscopy. Further, CCILs were used as organocatalyst in the enantioselective reduction of aromatic prochiral ketones to achieve corresponding chiral secondary alcohols.
- Kaur, Nirmaljeet,Chopra, Harish Kumar
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- General Strategy for Integrated Bioorthogonal Prodrugs: Pt(II)-Triggered Depropargylation Enables Controllable Drug Activation in Vivo
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Bioorthogonal decaging reactions for controllable drug activation within complex biological systems are highly desirable yet extremely challenging. Herein, we find a new class of Pt(II)-triggered bioorthogonal cleavage reactions in which Pt(II) but not Pt(IV) complexes effectively trigger the cleavage of O/N-propargyl in a variety of ranges of caged molecules under biocompatible conditions. Based on these findings, we propose a general strategy for integrated bioorthogonal prodrugs and accordingly design a prodrug 16, in which a Pt(IV) moiety is covalently connected with an O2-propargyl diazeniumdiolate moiety. It is found that 16 can be specifically reduced by cytoplasmic reductants in human ovarian cancer cells to liberate cisplatin, which subsequently stimulates the cleavage of O2-propargyl to release large amounts of NO in situ, thus generating synergistic and potent tumor suppression activity in vivo. Therefore, Pt(II)-triggered depropargylation and the integration concept might provide a general strategy for broad applicability of bioorthogonal cleavage chemistry in vivo.
- Sun, Tao,Lv, Tian,Wu, Jianbing,Zhu, Mingchao,Fei, Yue,Zhu, Jie,Zhang, Yihua,Huang, Zhangjian
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p. 13899 - 13912
(2020/12/02)
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- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
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A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
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supporting information
p. 16702 - 16707
(2020/10/27)
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- Total Synthesis of the Congested, Bisphosphorylated Morganella morganii Zwitterionic Trisaccharide Repeating Unit
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Zwitterionic polysaccharides (ZPSs) activate T-cell-dependent immune responses by major histocompatibility complex class II presentation. Herein, we report the first synthesis of a Morganella morganii ZPS repeating unit as an enabling tool in the synthesis of novel ZPS materials. The repeating unit incorporates a 1,2-cis-α-glycosidic bond; the problematic 1,2-trans-galactosidic bond, Gal-β-(1 → 3)-GalNAc; and phosphoglycerol and phosphocholine residues which have not been previously observed together as functional groups on the same oligosaccharide. The successful third-generation approach leverages a first in class glycosylation of a phosphoglycerol-functionalized acceptor. To install the phosphocholine unit, a highly effective phosphocholine donor was synthesized.
- Keith, D. Jamin,Townsend, Steven D.
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supporting information
p. 12939 - 12945
(2019/08/22)
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- Visible-Light-Mediated, Chemo- and Stereoselective Radical Process for the Synthesis of C-Glycoamino Acids
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An approach for efficient synthesis of C-glycosyl amino acids is described. Different from typical photoredox-catalyzed reactions of imines, the new process follows a pathway in which α-imino esters serve as electrophiles in chemoselective addition reactions with nucleophilic glycosyl radicals. The process is highlighted by the mild nature of the reaction conditions, the highly stereoselectivity attending C-C bond formation, and its applicability to C-glycosylations using both armed and disarmed pentose and hexose derivatives.
- Ji, Peng,Zhang, Yueteng,Wei, Yongyi,Huang, He,Hu, Wenbo,Mariano, Patrick A.,Wang, Wei
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supporting information
p. 3086 - 3092
(2019/05/01)
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- One-Pot Absolute Stereochemical Identification of Alcohols via Guanidinium Sulfate Crystallization
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A novel technique for the absolute stereochemical determination of alcohols has been developed that uses crystallization of guanidinium salts of organosulfates. The simple one-pot, two-step process leverages facile formation of guandinium organosulfate single crystals for the straightforward determination of the absolute stereochemistry of enantiopure alcohols by means of X-ray crystallography. The strong hydrogen bonding network drives the stability of the crystal lattice and allows for a diverse range of organic alcohol substrates to be analyzed.
- Brummel, Beau R.,Lee, Kinsey G.,McMillen, Colin D.,Kolis, Joseph W.,Whitehead, Daniel C.
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p. 9622 - 9627
(2019/12/02)
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- The 2,2-Dimethyl-2-(ortho-nitrophenyl)acetyl (DMNPA) Group: A Novel Protecting Group in Carbohydrate Chemistry
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The 2,2-dimethyl-2-(ortho-nitrophenyl)acetyl (DMNPA) group was introduced to synthetic carbohydrate chemistry as a protecting group (PG) for the first time. Benefiting from a unique chemical structure and novel deprotection conditions, the DMNPA group can be cleaved rapidly and mutually orthogonal to other PGs. Orchestrated application of the DMNPA group with other PGs led to the highly efficient synthesis of the glycan of thornasterside A.
- Liu, Hui,Zhou, Si-Yu,Wen, Guo-En,Liu, Xu-Xue,Liu, De-Yong,Zhang, Qing-Ju,Schmidt, Richard R.,Sun, Jian-Song
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supporting information
p. 8049 - 8052
(2019/10/11)
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- Amino-polystyrene supported hexaethylene glycol-bridged ionic liquid as an efficient heterogeneous catalyst for water-mediated nucleophilic hydroxylation
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We report a simple and eco-friendly method for producing an amino-polystyrene supported hexaethylene glycol-bridged ionic liquid (APS-HEGBIL) based on the copolymerization of amino-styrene with 1-vinyl imidazolium ionic liquid bearing hexaethylene glycol moieties, and its characterization by several analytical techniques. The resulting APS-HEGBIL catalyst was found to be remarkably efficient at catalyzing the selective nucleophilic hydroxylation of alkyl halides to produce the corresponding alcohols in water, which acted as a solvent and a nucleophilic hydroxide source. The catalyst was easily recycled and maintained its catalytic activity and stability after ten cycles with excellent yields. The main attributes of the catalyst were that it significantly enhanced the nucleophilicity of water during reactions and promoted the rapid conversions of polar and base-sensitive alkyl halide reactants to alcohols in excellent yields. The combination of ionic liquids and polymeric materials afforded quasi-homogeneous catalysts that were recycled by simple filtration and provided environmentally benign means for conducted catalytic procedures.
- Reddy, Mudumala Veeranarayana,Kang, Seok Min,Yoo, Suah,Woo, Sang Sik,Kim, Dong Wook
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p. 9435 - 9442
(2019/04/01)
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- Secondary amine salt catalyzed controlled activation of 2-deoxy sugar lactols towards alpha-selective dehydrative glycosylation
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A new organocatalytic glycosylation method exploiting the lactol functionality has been disclosed. The catalytic generation of glycosyl oxacarbenium ions from lactols under forcible conditions via weakly Br?nsted-acidic, readily available secondary amine salts affects the diastereoselective glycosylation of 2-deoxypyranoses and furanoses. This operationally simple iminium catalyzed activation of 2-deoxy hemi-acetals is a potential alternative to the existing cumbersome methods that need specialized handling. The mechanisms for this unique transformation and kinetic/thermodynamic effects have been discussed based on both experimental evidence and theoretical studies.
- Ghosh, Titli,Mukherji, Ananya,Srivastava, Hemant Kumar,Kancharla, Pavan K.
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supporting information
p. 2870 - 2875
(2018/05/03)
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- Synthesis of reversed C-glycopeptide mimics monomer from galactose via passerini reaction
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C-glycopeptidomimetics are formed by the condensation of sugar unit and analogues of amino acid residue which generates a new carbon-carbon sigma bond. In glycopeptides, this condensation occurs in side chain of amino acid but introduction of isonitrile moiety on N-terminal of amino acid mimic unit can also be a route to produce such compounds. It is observed that C-glycopeptidomimetics are more stable than their N- and O-analogues under physiological conditions but their synthesis is a challenging task due to relatively less reactive C-6 position of hexose. In present work, synthesis of reversed C-glycopeptidomimetics (pseudoglycopeptides) was done by Passerini reaction protocol which is famous for peptide synthesis due to its mild conditions and easy workup. This paper discusses the use of α-D-galactose, a cheap and easily available monosaccharide to prepare reversed C-glycopeptidomimetics. The term reversed C-glycopeptidomimetics is derived for its analogy with reversed C-nucleosides, as in these reactions, instead of anomeric carbon i.e. more reactive site, C-6 undergoes to produce desired products.
- Jalib, Muhammad Atif,Nabeel, Muhammad,Ali, Firdous Imran,Bari, Ahmed,Musharraf, Syed Ghulam,Hashmi, Imran Ali
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p. 792 - 798
(2018/07/15)
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- Synthesis and antimicrobial evaluation of amino sugar-based naphthoquinones and isoquinoline-5,8-diones and their halogenated compounds
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Antibiotic resistance has emerged as a serious global public health problem and lately very few antibiotics have been discovered and introduced into clinical practice. Therefore, there is an urgent need for the development of antibacterial compounds with new mechanism of action, especially those capable of evading known resistance mechanisms. In this work two series of glycoconjugate and non-glycoconjugate amino compounds derived from of isoquinoline-5,8-dione and 1,4-naphthoquinone and their halogenated derivatives were synthesized and evaluated for antimicrobial activity against Gram-positive (Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, S. epidermidis ATCC 12228, S. simulans ATCC 27851) and Gram-negative bacteria (E. coli ATCC 25922, Proteus mirabilis ATCC 15290, K. pneumoniae ATCC 4352 and P. aeruginosa ATCC 27853) strains of clinical importance. This study revealed that glycoconjugate compounds derived from halogeno-substituted naphthoquinones were more active against Gram-negative strains, which cause infections whose treatment is even more difficult, according to the literature. These molecules were also more active than isoquinoline-5,8-dione analogues with minimum inhibitory concentration (MIC = 4–32 μg/mL) within Clinical and Laboratory Standard Institute MIC values (CLSI 0.08–256 μg/mL). Interestingly the minimal bactericidal concentration (MBC) values of the most active compounds were equal to MIC classifying them as bactericidal agents against Gram-negative bacteria. Sixteen compounds among eighteen carbohydrate-based naphthoquinones tested showed no hemolytic effects on health human erythrocytes whereas more susceptibility to hemolytic cleavage was observed when using non-glycoconjugate amino compounds. In silico Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) evaluation also pointed out that these compounds are potential for oral administration with low side effects. In general, this study indicated that these compounds should be exploited in the search for a leading substance in a project aimed at obtaining new antimicrobials more effective against Gram-negative bacteria.
- Dias, Flaviana R.F.,Novais, Juliana S.,Devillart, Talita A. do Nascimento Santos,da Silva, Wanderson Amaral,Ferreira, Matheus O.,Loureiro, Raquel de S.,Campos, Vinícius R.,Ferreira, Vitor F.,de Souza, Maria C.B.V.,Castro, Helena C.,Cunha, Anna C.
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- Synthesis method and application of sialylated TF antigen and its fluorination derivatives
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The invention discloses a synthesis method and an application of a sialylated TF antigen and its fluorination derivatives. The method includes the following steps: (1) chemically synthesizing fluorogalactose and fluorogalactosamine analogues; (2) chemically synthesizing a fluorinated TF antigen; and (3) synthesizing the sialylated TF antigen and its fluorination derivatives through an enzyme technology. The flexibility of a chemical synthesis technology is combined with the high regioselectivity and the high efficiency of the enzyme synthesis technology, so the enzymatic synthesis of the fluorosialylated TF antigen is achieved for the first time, and the disadvantages of many synthesis steps, poor stereoselectivity, low yield and use of a heavy metal salt in existing chemical synthesis ofthe fluorosialylated TF antigen are overcome. A fluorotumor-associated carbohydrate antigen has a higher stability than natural carbohydrate antigen, so the sialylated TF antigen and its fluorinationderivatives have a broad application prospect in the development of novel antitumor vaccines.
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Paragraph 0075; 0077-0079
(2018/07/07)
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- A Green and Sustainable Route to Carbohydrate Vinyl Ethers for Accessing Bioinspired Materials with a Unique Microspherical Morphology
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Synthesizing chemicals and materials from renewable sources is one of the main aims of modern science. Carbohydrates represent excellent renewable natural raw materials that are ecofriendly, inexpensive, and biologically compatible. A green procedure has been developed for the vinylation of carbohydrates by using readily available calcium carbide. Various carbohydrates were utilized as starting materials, resulting in mono-, di-, and tetravinyl ethers in high to excellent yields (81–92 %). The synthesized biobased vinyl ethers were utilized as monomers in free radical and cationic polymerizations. A unique combination of a smooth surface and intrinsic microcompartments was achieved in the synthesized materials. Two types of biobased materials were prepared involving microspheres and intrinsic hollow compartments in polymers. Scanning electron microscopy with built-in ion beam cutting was applied to reveal the spatial hierarchical structures in 3D space.
- Rodygin, Konstantin S.,Werner, Irina,Ananikov, Valentine P.
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p. 292 - 298
(2017/12/26)
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- Unraveling the Photodeprotection Mechanism of Anthraquinon-2-ylmethoxycarbonyl-Caged Alcohols Using Time-Resolved Spectroscopy
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Anthraquinone (AQ) compounds have been used as photolabile protecting groups (PPGs) to protect alcohols, ketones, and carboxylic acids. However, because of the lack of direct spectroscopic information for the transient species and intermediates related with the deprotection reaction(s), the photorelease mechanism(s) of these systems are still largely unknown. In this contribution, we detail a time-resolved spectroscopic investigation using anthraquinone-protected galactose (1) and adenosine (2) to investigate the photodeprotection reaction mechanism(s) of these kinds of AQ-PPGs. It was found that, in THF-H2O solvents, the ketyl radical species generated for 1 and 2 was found to be a reactive intermediate that then formed a dihydroxyanthracene species. The photodeprotection then occurred with the accompaniment of a decarboxylation process. These results provide an improved understanding for how AQ-PPGs work and will help assist in the design and applications of selected anthraquinone derivatives as a PPG platform, especially in aqueous environments more relevant for use in biological systems.
- Guo, Yan,Song, Qingqing,Wang, Jialin,Ma, Jiani,Zhang, Xiting,Phillips, David Lee
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supporting information
p. 13454 - 13462
(2018/11/03)
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- Introduction of 4-Chlorophenyl: A Protecting Group for the Hydroxy Function
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4-Chlorophenyl ether was utilized as a new protecting group for the hydroxy function. This group was readily introduced to a sugar hydroxy group by using diaryliodonium triflate. Regioselective introduction of this protecting group at the vicinal cis -diol was achieved by using a copper catalyst and diaryliodonium triflate. This protecting group is stable under the Lewis acidic conditions of glycosylation, but it can be readily removed by the initial conversion into the corresponding 4-methoxyphenyl ether with use of a Pd catalyst, followed by oxidation with ammonium cerium (IV) nitrate [(NH 4) 2 Ce(NO 3) 6 ] (CAN).
- Otsuka, Yuji,Yamamoto, Toshihiro,Fukase, Koichi
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supporting information
p. 1510 - 1516
(2018/04/24)
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- Practical preparation of mono- and di-O-isopropylidene derivatives of monosaccharides and methyl 4,6-O-benzylidene glycosides from free sugars in a deep eutectic solvent
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Free sugars were rapidly converted into the corresponding di-O-isopropylidene derivatives and methyl O-benzylidene glycosides in excellent yields and purity in a deep eutectic solvent made from choline chloride and malonic acid (ChCl:MA). Reaction conditions were mild; work-up was easy, and further purification was not necessary. Given the inexpensive, nontoxic, and recyclable nature of ChCl:MA, this protocol is environmental friendly.
- Rokade, Sunil M.,Bhate, Prakash M.
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- Click Inspired Synthesis of 1,2,3-Triazole-linked 1,3,4-Oxadiazole Glycoconjugates
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The glycoconjugation of biologically privileged 1,3,4-oxadiazole scaffold is described via Cu(I)-catalyzed azide–alkyne cycloaddition. A series of glycosyl alkynes 1b–i, obtained from various commercial sugars, were treated with azide functionalized 1,3,4-oxadiazole using click chemistry to access triazole-linked glycosylated 1,3,4-oxadiazoles 10b–i in good yields. The structure of the developed glycoconjugates has been ascertained by extensive spectroscopic analysis (1H &13C NMR, IR, and MS).
- Kushwaha, Divya,Tiwari, Vinod K.
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p. 2454 - 2462
(2017/07/25)
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- 3-Aminodeoxypyranoses in Glycosylation: Diversity-Oriented Synthesis and Assembly in Oligosaccharides
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A concise, diversity-oriented approach for the synthesis of naturally occurring 3-amino- and 3-nitro-2,3,6-trideoxypyranose derivatives and analogues thereof from simple sugars has been developed. In addition, we investigated the synthesis of various 3-aminoglycosyl donors and their application in glycosylation reactions. These studies led to the successful synthesis of a tetrasaccharide containing four different 3-aminosugar components using ortho-alkynylbenzoate donors.
- Zeng, Jing,Sun, Guangfei,Yao, Wang,Zhu, Yangbin,Wang, Ruobin,Cai, Lei,Liu, Ke,Zhang, Qian,Liu, Xue-Wei,Wan, Qian
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supporting information
p. 5227 - 5231
(2017/04/27)
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- Synthesis and in?vitro Bioactivity Evaluation of New Galactose and Fructose Ester Derivatives of 5-Aminosalicylic Acid
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Inflammatory bowel disease (IBD) is the main risk factor for developing colorectal cancer which is common in patients of all ages. 5-Aminosalicylic acid (5-ASA), structurally related to the salicylates, is highly active in the treatment of IBD with minor side effects. In this study, the synthesis of galactose and fructose esters of 5-ASA was planned to evaluate the role of glycoconjugation on the bioactivity of the parent drug. The antibacterial activity of the new compounds were evaluated against two Gram-negative and two Gram-positive species of bacteria, with a notable effect observed against Staphylococcus aureus and Escherichia coli in comparisons with the 5-ASA. Cytotoxicity testing over HT-29 and 3T3 cell lines indicated that the toxicity of the new products against normal cells was significantly reduced compared with the original drug, whereas their activity against cancerous cells was slightly decreased. The anti-inflammatory activity test in RAW264.7 macrophage cells indicated that the inhibition of nitric oxide by both of the monosaccharide conjugated derivatives was slightly improved in comparison with the non-conjugated drug.
- Yousefi, Samira,Bayat, Saadi,Rahman, Mohd Basyaruddin Abdul,Ibrahim, Zalikha,Abdulmalek, Emilia
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- Method for preparing and removing saccharide hydroxyl protecting group dimethyl phenylacetyl DMNA
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The invention relates to a method for preparing and removing saccharide hydroxyl protecting group dimethyl phenylacetyl DMNA. The method comprises the following steps: (1) efficiently introducing saccharide hydroxyl protecting group dimethyl phenylacetyl into saccharide hydroxyl; and (2) efficiently removing a hydroxyl protecting group shown in the description. The method is environmentally friendly and has the advantages that the advantages that the preparation is simple, the introduction is efficient, the operation is easy, the removal is efficient, and the application range is wide; and furthermore, a protecting group has very good stereoselectivity when being used for protecting 2-hydroxyl of a glycosyl donor, so that the development and application of the protecting group are promoted.
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Paragraph 0026; 0027; 0028; 0098; 0099; 0100
(2017/08/29)
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- Synthesis and evaluation of antibacterial and antitumor activities of new galactopyranosylated amino alcohols
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Three series of d-galactose derivatives linked to a lipophilic aminoalcohol moiety were synthesized and their antibacterial activity was evaluated against Mycobacterium tuberculosis and representative species of Gram positive and Gram negative bacteria. Five out of the thirteen tested compounds displayed activity against M. tuberculosis, with a minimal inhibitory concentration (MIC) of 12.5 μg/mL and seven compounds were active against the four bacterial strains tested. The best results were obtained for amino alcohols 10 and 11 against Staphylococcus epidermidis (MIC Combining double low line 2 μg/mL). The antitumor activity was evaluated against three tumor cell lines (MCF-7, HeLa and MO59J) and compared to the normal cell line GM07492A. The results showed that the lowest IC50 values were observed for the amino alcohol 16 against MCF-7 (11.9 μM) and MO59J (10.0 μM).
- De Souza Fernandes, Fábio,Fernandes, Tayrine Silva,Da Silveira, Lígia Souza,Caneschi, Wiliam,Louren?o, Maria Cristina S.,Diniz, Claudio G.,De Oliveira, Pollyanna Francielli,Martins, Sabrina De Paula Lima,Pereira, Daiane Eleutério,Tavares, Denise Crispim,Le Hyaric, Mireille,De Almeida, Mauro V.,Couri, Mara Rubia C.
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p. 203 - 210
(2015/12/08)
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- Amphiphilic diblock terpolymer PMAgala-b-P(MAA-co-MAChol)s with attached galactose and cholesterol grafts and their intracellular pH-responsive doxorubicin delivery
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In this work, a series of diblock terpolymer poly(6-O-methacryloyl-d-galactopyranose)-b-poly(methacrylic acid-co-6-cholesteryloxy hexyl methacrylate) amphiphiles bearing attached galactose and cholesterol grafts denoted as the PMAgala-b-P(MAA-co-MAChol)s were designed and prepared, and these terpolymer amphiphiles were further exploited as a platform for intracellular doxorubicin (DOX) delivery. First, employing a sequential RAFT strategy with preliminarily synthesized poly(6-O-methacryloyl-1,2:3,4-di-O-isopropylidene-d-galactopyranose) (PMAIpGP) macro-RAFT initiator and a successive trifluoroacetic acid (TFA)-mediated deprotection, a series of amphiphilic diblock terpolymer PMAgala-b-P(MAA-co-MAChol)s were prepared, and were further characterized by NMR, Fourier transform infrared spectrometer (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and a dynamic contact angle testing instrument (DCAT). In aqueous media, spontaneous micellization of the synthesized diblock terpolymer amphiphiles were continuously examined by critical micellization concentration assay, dynamic light scattering (DLS), and transmission electron microscopy (TEM), and the efficacies of DOX loading by these copolymer micelles were investigated along with the complexed nanoparticle stability. Furthermore, in vitro DOX release of the drug-loaded terpolymer micelles were studied at 37 °C in buffer under various pH conditions, and cell toxicities of as-synthesized diblock amphiphiles were examined by MTT assay. Finally, with H1299 cells, intracellular DOX delivery and localization by the block amphiphile vectors were investigated by invert fluorescence microscopy. As a result, it was revealed that the random copolymerization of MAA and MAChol comonomers in the second block limited the formation of cholesterol liquid-crystal phase and enhanced DOX loading efficiency and complex nanoparticle stability, that ionic interactions between the DOX and MAA comonomer could be exploited to trigger efficient DOX release under acidic condition, and that the diblock terpolymer micellular vector could alter the DOX trafficking in cells. Hence, these suggest the pH-sensitive PMAgala-b-P(MAA-co-MAChol)s might be further exploited as a smart nanoplatform toward efficient antitumor drug delivery.
- Wang, Zhao,Luo, Ting,Sheng, Ruilong,Li, Hui,Sun, Jingjing,Cao, Amin
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- Tetranuclear zinc cluster: A dual purpose catalyst for per-: O -acetylation and de- O -acetylation of carbohydrates
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The trifluoroacetic acid adduct of tetranuclear zinc cluster Zn4(OCOCF3)6O catalysis in per-O-acetylation and de-O-acetylation of carbohydrates at 70 °C can be tuned by adjusting the reaction medium. Per-O-acetylation of hexopyranoses with a near stoichiometric amount of acetic anhydride in toluene resulted in the exclusive formation of pyranosyl products as an anomeric mixture, whereas de-O-acetylation of acetates occurred in methanol in high yields. In the latter, methanol acts as both nucleophile and solvent, and the reaction conditions were compatible to acid- and base-sensitive groups and amino acid derivatives.
- Lin, Ting-Wei,Adak, Avijit K.,Lin, Hong-Jyune,Das, Anindya,Hsiao, Wei-Chen,Kuan, Ting-Chun,Lin, Chun-Cheng
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p. 58749 - 58754
(2016/07/07)
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- Mild and selective deprotection of tert -butyl(dimethyl)silyl ethers with catalytic amounts of sodium tetrachloroaurate(III) dihydrate
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A simple and mild method for the removal of tert-butyl(dimethyl)silyl (TBS) protecting groups with catalytic amounts of sodium tetrachloroaurate(III) dihydrate is described. The procedure permits selective deprotection of aliphatic TBS ethers in good to excellent yields in the presence of aromatic TBS ethers, aliphatic triisopropylsilyl ethers, aliphatic tert-butyl(diphenyl)silyl ethers, or sterically hindered aliphatic TBS ethers. Additionally, TBS ethers can also be transformed into 4-methoxybenzyl ethers or methyl ethers in one pot by using larger quantities of the catalyst and a higher reaction temperature.
- Zhang, Qi,Kang, Xiuqin,Long, Lei,Zhu, Lijuan,Chai, Yonghai
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- Synthesis, characterization, and biological interaction of glyconanoparticles with controlled branching
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Branched amphiphilic copolymers were synthesized through the reversible addition - fragmentation chain transfer (RAFT) chain extension of a poly(methyl acrylate) macro-chain transfer agent using a protected galactose monomer and a polymerizable chain transfer agent branching unit. After galactose deprotection, the copolymers were self-assembled via nanoprecipitation. The resultant nanoparticles were analyzed for their size, shape, and biological interaction with a galactose binding lectin. Using light scattering, the nanoparticles were determined to be solid spheres. Nanoparticles containing branched glycoblocks bound significantly more lectin than those containing comparable linear blocks. By adjusting the molecular weight and branching of the copolymer, the size of the self-assembled nanoparticle and the saccharide density on its surface can be varied. (Figure Presented).
- Liau, Walter T.,Bonduelle, Colin,Brochet, Marion,Lecommandoux, Sbastien,Kasko, Andrea M.
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p. 284 - 294
(2015/01/30)
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- Synthesis of a new class of naphthoquinone glycoconjugates and evaluation of their potential as antitumoral agents
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A novel series of carbohydrate-based naphthoquinones was synthesized and evaluated for cytotoxicity against different cancer cell lines. The compounds derived from 5-hydroxy-1,4-naphthoquinone (juglone) showed better cytotoxicity profiles against HCT-116, A-549 and MDA-MB 435 human cancer cells than the parent compound. The results suggest that the hydroxyl group on the aromatic ring increased the pro-oxidant activity of these new naphthoquinone derivatives. Furthermore, two derivatives were found to be more active against melanoma cells (MDA-MB435) than the clinically useful anticancer agent doxorubicin, and none of the compounds caused mouse erythrocyte lysis.
- Campos, Vinicius R.,Cunha, Anna C.,Silva, Wanderson A.,Ferreira, Vitor F.,Santos De Sousa, Carla,Fernandes, Patrícia D.,Moreira, Vinícius N.,Da Rocha, David R.,Dias, Flaviana R. F.,Montenegro, Raquel C.,De Souza, Maria C. B. V.,Boechat, Fernanda Da C. S.,Franco, Caroline F. J.,Resende, Jackson A. L. C.
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p. 96222 - 96229
(2015/11/24)
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- Synthesis, characterization, cytotoxic and antitubercular activities of new gold(I) and gold(III) complexes containing ligands derived from carbohydrates
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Novel gold(I) and gold(III) complexes containing derivatives of d-galactose, d-ribose and d-glucono-1,5-lactone as ligands were synthesized and characterized by IR, 1H, and 13C NMR, high resolution mass spectra and cyclic voltammetry. The compounds were evaluated in vitro for their cytotoxicity against three types of tumor cells: cervical carcinoma (HeLa) breast adenocarcinoma (MCF-7) and glioblastoma (MO59J) and one non-tumor cell line: human lung fibroblasts (GM07492A). Their antitubercular activity was evaluated as well expressed as the minimum inhibitory concentration (MIC90) in μg/mL. In general, the gold(I) complexes were more active than gold(III) complexes, for example, the gold(I) complex (1) was about 8.8 times and 7.6 times more cytotoxic than gold(III) complex (8) in MO59J and MCF-7 cells, respectively. Ribose and alkyl phosphine derivative complexes were more active than galactose and aryl phosphine complexes. The presence of a thiazolidine ring did not improve the cytotoxicity. The study of the cytotoxic activity revealed effective antitumor activities for the gold(I) complexes, being more active than cisplatin in all the tested tumor cell lines. Gold(I) compounds (1), (2), (3), (4) and (6) exhibited relevant antitubercular activity even when compared with first line drugs such as rifampicin.
- Chaves, Joana Darc Souza,Damasceno, Jaqueline Lopes,Paula, Marcela Cristina Ferreira,De Oliveira, Pollyanna Francielli,Azevedo, Gustavo Chevitarese,Matos, Renato Camargo,Louren?o, Maria Cristina S.,Tavares, Denise Crispim,Silva, Heveline,Fontes, Ana Paula Soares,De Almeida, Mauro Vieira
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p. 845 - 860
(2015/09/29)
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- Synthesis and membranoprotective properties of new disulfides with monoterpene and carbohydrate fragments
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A cooxidation of carbohydrate and terpene thiols gives mixtures of disulfides containing 51 - 90% of the unsymmetric product. Membranoprotective and antioxidant properties of obtained unsymmetric and symmetric disulfides were evaluated based on their ability to inhibit the H2O2-induced hemolysis of erythrocytes, as well as the accumulation of secondary products of the peroxy oxidation of lipids and the oxidation of hemoglobin.
- Pestova,Izmestev,Shevchenko,Rubtsova,Kuchin
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p. 723 - 731
(2015/11/27)
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- Structurally Simple Benzyl-Type Photolabile Protecting Groups for Direct Release of Alcohols and Carboxylic Acids
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Structurally simple benzyl-type photolabile protecting groups (PPGs) have been developed to release alcohols and carboxylic acids. Release of two substrates from one PPG chromophore has also been accomplished. (Chemical Equation Presented).
- Wang, Pengfei,Lu, Wenya,Devalankar, Dattatray A.,Ding, Zhenying
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supporting information
p. 2114 - 2117
(2015/05/13)
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- Synthesis and antiproliferative activity of 8-hydroxyquinoline derivatives containing a 1,2,3-triazole moiety
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Twelve novel 8-hydroxyquinoline derivatives were synthesized with good yields by performing coppercatalyzed Huisgen 1,3-dipolar cycloaddition ("click" reaction) between an 8-O-alkylated-quinoline containing a terminal alkyne and various aromatic or protected sugar azides. These compounds were evaluated in vitro for their antiproliferative activity on various cancer cell types. Protected sugar derivative 16 was the most active compound in the series, exhibiting potent antiproliferative activity and high selectivity toward ovarian cancer cells (OVCAR-03, GI50 -1); this derivative was more active than the reference drug doxorubicin (OVCAR-03, GI50 = 0.43 μg mL-1). In structureeactivity relationship (SAR) studies, the physico-chemical parameters of the compounds were evaluated and docking calculations were performed for the a-glucosidase active site to predict the possible mechanism of action of this series of compounds.
- De O. Freitas, Luiza B.,Borgati, Thiago F.,De Freitas, Rossimiriam P.,Ruiz, Ana L. T. G.,Marchetti, Gabriela M.,De Carvalho, Joo E.,Da Cunha, Elaine F. F.,Ramalho, Teodorico C.,Alves, Rosemeire B.
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p. 595 - 604
(2015/03/14)
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- A concise total synthesis of puberulic acid, a potent antimalarial agent
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Efficient and practical total synthesis of puberulic acid has been accomplished via 8 steps, with 54% overall yield, and only two C-C bond formations, without the introduction of oxygen atoms into the core skeleton. Construction of the tropolone framework as the key transformation was achieved by multi-tandem oxidation of the aliphatic-triol, from d-(+)-galactose as the starting material.
- Sennari, Goh,Hirose, Tomoyasu,Iwatsuki, Masato,Omura, Satoshi,Sunazuka, Toshiaki
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supporting information
p. 8715 - 8718
(2014/07/22)
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- Synthesis of genistein coupled with sugar derivatives and their inhibitory effect on nitric oxide production in macrophages
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The isoflavone genistein 1 and some derivatives modulate IL-12, TNF-α and NO production by macrophages and lung cancer cell lines, and improve the clinical signs of experimental autoimmune encephalomyelitis (EAE). Seven genistein derivatives connected at C-6 position of a sugar, such as d-glucose and d-galactose, were synthesized. The ability to modulate macrophage response was evaluated, showing variable inhibition capacity of NO and TNF-α production in J774.A1 and RAW 264.7. Five of the seven compounds were non-cytotoxic; compound 8 was more effective to inhibit NO and TNF-α production, without affecting cell viability.
- Junior, Celso O.R.,Castro, Sandra B.R.,Pereira, Adriane A.,Alves, Caio C.S.,Oliveira, Erick E.,Rêgo, Renata T.,Ferreira, Ana Paula,De Almeida, Mauro V.
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p. 615 - 620
(2014/09/17)
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- METHODS AND COMPOSITIONS FOR MAKING ANTIBODIES AND ANTIBODY DERIVATIVES WITH REDUCED CORE FUCOSYLATION
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The invention provides methods and compositions for preparing antibodies and antibody derivatives with reduced core fucosylation.
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Paragraph 0167; 0168
(2014/02/16)
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- Reductive removal of methoxyacetyl protective group using sodium borohydride
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Herein, we have developed a mild and selective reductive deprotection method for the MAc protected alcohols using sodium borohydride. The new deprotection conditions provide a complete orthogonality between O-MAc and other protecting groups such as tert-butyl ester, N-Boc, Fmoc, Cbz, O-TBDMS, N-benzyl, O-benzyl, O-acetyl, N-acetyl, N-MAc, etc. In addition to O-MAc deprotection, this method is also applicable for S-MAc deprotection.
- Gadekar, Pradip K.,Hoermann, Maryann,Corbo, Faith,Sharma, Rajiv,Sarveswari,Roychowdhury, Abhijit
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p. 503 - 506
(2014/01/06)
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- In(III) triflate-catalyzed detritylation and glycosylation by solvent-free ball milling
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A highly efficient In(III) triflate-assisted method for the detritylation of O-trityl derivatives of carbohydrates, phenols, and alcohols using solvent-free mechanochemical method is described. In the case of carbohydrates, further reaction in the presence of an acceptor sugar leads to highly efficient glycosylation in the same pot resulting in the formation of the desired glycoside-product in very high yields. The method was applied successfully to the synthesis of a combinatorial library of galactose-based (1,6)-linked cyclohexa-, hepta-, and octasaccharides on gram scale.
- Kumar, Vajinder,Yadav, Narender,Kartha, K.P. Ravindranathan
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- Synthesis, surface tension properties and antibacterial activities of amphiphilic d-galactopyranose derivatives
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Several amphiphilic d-galactopyranose derivatives were synthesized in which the glycosidic moiety was separated from the hydrophobic alkyl chain (along 8 or 12 carbon atoms) by a spacer arm (butyl, butynyl or benzyl) in order to increase their surfactant properties and to obtain new antibacterial compounds. The surface tensions of the products were analyzed by Critical Micelle Concentration (CMC) and γCMC measurements and the antimicrobial activities were assayed against 10 bacterial species by Minimum Inhibitory Concentration (MIC) determination in liquid broth. The introduction of an aliphatic spacer arm increased the amphiphilic properties of the compounds and the CMC values were 40-500 times lower than their analogs without spacer arm. In the same manner, the spacer arms significantly increased the antibacterial power of the compounds. The products 4d and 4e exhibiting a C12 alkyl chain and an aliphatic spacer arm (butyl and butynyl) were the best surfactants (CMC = 0.023 and 0.032 mmol/L, respectively) and presented also the best antibacterial activities (MIC = 15.62 and 3.91 μg/mL for Micrococcus luteus, respectively). But the antibacterial activity of the newly synthesized products seemed to depend more on the cell wall composition of the bacteria than only on the amphiphilic character of the compounds.
- Chaveriat, Ludovic,Gosselin, Isabelle,Machut, Cecile,Martin, Patrick
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p. 177 - 186
(2013/06/04)
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- Synthesis and photophysical properties of fluorescent 2,1,3- benzothiadiazole-triazole-linked glycoconjugates: Selective chemosensors for Ni(II)
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The synthesis of new fluorescent 2,1,3-benzothiadiazole-triazole-linked glycoconjugates is described by a straightforward synthetic route, using a copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC). UV-visible (UV-vis) and steady-state fluorescence in solution were applied in order to characterize its photophysical behavior. The dyes present absorption in the violet region with fluorescence emission in the cyan-green region, which can be related to the methoxy derivatives due to an intramolecular charge transfer (ICT) in the excited state. The studied derivatives present potential optical application since combine large extinction coefficient for absorption, large Stokes shift and high fluorescence emission. Additionally, these dyes exhibit binding selectivity to Ni+2 among a series of cations in CH 3CN solution.
- Moro, Angélica V.,Ferreira, Patrícia C.,Migowski, Pedro,Rodembusch, Fabiano S.,Dupont, Jairton,Lüdtke, Diogo S.
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p. 201 - 206
(2013/01/15)
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- Nano n-propylsulfonated magnetic γ-Fe 2O 3 as an efficient and reusable catalyst for the synthesis O-isopropylidene derivatives of carbohydrates
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Nano n-propylsulfonated γ-Fe2O3 was found to be a highly efficient, reusable heterogeneous catalyst for the conversion of a range of monosaccharides and some of their derivatives to the corresponding O-isopropylidene derivatives in good to excellent yields by refluxing the reaction mixture in dry acetone. The magnetic property of the catalyst enabled its separation from the reaction mixture by a simple process of filtration along with the aid of an external magnet. The efficiency of the catalyst was found to be largely unaffected for at least up to six cycles of reuse, thus proving the new methodology to be environmentally rewarding besides being simple and facile in operation.
- Zhang, Xiaoran,Zhang, Changqiang
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p. 249 - 258
(2013/08/15)
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- Water soluble and fluorescent copolymers as highly sensitive and selective fluorescent chemosensors for the detection of cyanide anions in biological media
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We report a simple colorimetric method based on a water soluble polymer (WSP) for the sensitive and selective detection of cyanide in a biological solution. The WSPs were prepared from a radical polymerization of a methacrylate with a cyanide chemosensor moiety based on a coumarin-dicyano-vinyl derivative motif, and the polymer was then rendered water soluble by copolymerizing this hydrophobic monomer with other glyco-conjugated methacrylate derivatives. The lowest concentration for the quantification of cyanide ions was 0.05 μM, and the polymer exhibited nearly no calorimetric response to the presence of other common anions. Therefore, the chemical incorporation of some carbohydrates, as lactose or its usual monosaccharide moieties (glucose, lactose), represents a new method for the implementation of polymers for the detection of cyanide anions in water, exhibiting both good selectivity and efficiency. The Royal Society of Chemistry 2013.
- Isaad, Jalal,Malek, Fouad,El Achari, Ahmida
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p. 22168 - 22175
(2013/11/06)
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- Fluorescently labeled substrates for monitoring α1,3- fucosyltransferase IX activity
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Fucosylation is often the final process in glycan biosynthesis. The resulting glycans are involved in a variety of biological processes, such as cell adhesion, inflammation, or tumor metastasis. Fucosyltransferases catalyze the transfer of fucose residues from the activated donor molecule GDP-β-L-fucose to various acceptor molecules. However, detailed information about the reaction processes is still lacking for most fucosyltransferases. In this work we have monitored α1,3-fucosyltransferase activity. For both donor and acceptor substrates, the introduction of a fluorescent ATTO dye was the last step in the synthesis. The subsequent conversion of these substrates into fluorescently labeled products by α1,3-fucosyltransferases was examined by high-performance thin-layer chromatography coupled with mass spectrometry as well as dual-color fluorescence cross-correlation spectroscopy, which revealed that both fluorescently labeled donor GDP-β-L-fucose-ATTO 550 and acceptor N-acetyllactosamine-ATTO 647N were accepted by recombinant human fucosyltransferase IX and Helicobacter pylori α1,3- fucosyltransferase, respectively. Analysis by fluorescence cross-correlation spectroscopy allowed a quick and versatile estimation of the progress of the enzymatic reaction and therefore this method can be used as an alternative method for investigating fucosyltransferase reactions. Fucosyl transfer: Two substrates of α1,3-fucosyltransferase IX have been labeled with ATTO dyes to monitor the enzymatically catalyzed transfer of the sugar moiety (see figure). The labeled guanosine diphosphate-fucose derivative was prepared by using cycloSal technology. The successful transfer reaction was first proven by high-performance thin-layer chromatography coupled with mass spectrometry. Fluorescence cross-correlation spectroscopy proved to be a suitable method for monitoring the enzyme activity.
- Lunau, Nathalie,Seelhorst, Katrin,Kahl, Stefanie,Tscherch, Kathrin,Stacke, Christina,Rohn, Sascha,Thiem, Joachim,Hahn, Ulrich,Meier, Chris
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p. 17379 - 17390
(2014/01/06)
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- The design, synthesis, and antioxidant activity of amphiphilic oximes and amidoximes
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New amphiphilic benzamidoxime, benzoxime, and aliphatic oxime derivatives of glycolipid mimetics were synthesized. The total antioxidant capacity of these amphiphilic derivatives was evaluated using DPPH assay. The observed antioxidant activity was the highest for benzamidoxime derivatives and glycolipid mimetics with two oxime functionalities, followed by benzoxime derivatives, glycolipid mimetics with one oxime group, and dimers of oxime. Due to their amphiphilic structure, which was a guidance for compound design and synthesis, these novel amphiphilic compounds can be proposed as potential antioxidants for tackling oxidative processes in two-phase systems, either biological (cell membranes) or artificial (emulsions).
- Gosenca, Mirjam,Mravljak, Janez,Gasperlin, Mirjana,Obreza, Ales
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p. 310 - 322
(2013/08/23)
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