- Synthesis of glycopolymer nanosponges with enhanced adsorption performances for boron removal and water treatment
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The high-affinity interactions between cis-diols and boric/boronic acid have been widely employed as a tool for carbohydrate analysis, protein separation and boron removal. Herein we report the design and synthesis of cyclodextrin-scaffolded glycopolymers as bifunctional nanosponges for boron removal and water treatment for the first time. Different glycopolymer nanosponges (GNs) have been successfully synthesized from monosaccharides and β-cyclodextrin via a combination of a cross-linking reaction, Fischer glycosylation and a click reaction. Such functional GNs are mesoporous polymer frameworks with cis-diol-containing saccharides immobilized on the surface, which have exhibited selective adsorption behaviour towards boric acid depending on the structure of the GNs and the loaded saccharides. The GNs have also shown remarkable adsorption rates and capacities for an organic dye as a model pollutant in this work. Secondary bonding, such as hydrogen bonding and van der Waals forces between the immobilized saccharides and the adsorbates is believed to be responsible for the significantly enhanced adsorption rates and capacities. Such bifunctional materials may exhibit potential applications in seawater desalination and water treatment.
- Liao, Xueping,Wang, Bingyu,Zhang, Qiang
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- Dendritic cell lectin-targeting sentinel-like unimolecular glycoconjugates to release an anti-HIV drug
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A series of cyclodextrin-based glycoconjugates, including glycoclusters and star glycopolymers, were synthesized via combination of CuAAC Huisgen coupling and copper-mediated living radical polymerization. These glycoconjugates showed high affinity binding to the human transmembrane lectin DC-SIGN and act as inhibitors to prevent the binding of HIV envelope protein gp120 to DC-SIGN at nanomolar concentrations. The star block glycopolymers showed high loading capacity of hydrophobic anticancer and anti-HIV drugs, indicating promising applications in HIV-therapeutic and smart drug delivery.
- Zhang, Qiang,Su, Lu,Collins, Jennifer,Chen, Guosong,Wallis, Russell,Mitchell, Daniel A.,Haddleton, David M.,Becer, C. Remzi
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- A host-guest supramolecular complex with photoregulated delivery of nitric oxide and fluorescence imaging capacity in cancer cells
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Herein we report the design, preparation, and properties of a supramolecular system based on a tailored nitric oxide (NO) photodonor and a rhodamine-labeled β-cyclodextrin conjugate. The combination of spectroscopic and photochemical experiments shows the absence of significant interchromophoric interactions between the host and the guest in the excited states. As a result, the complex is able to release NO under the exclusive control of visible light, as unambiguously demonstrated by direct detection of this transient species through an amperometric technique, and exhibits the typical red fluorescence of the rhodamine appendage. The supramolecular complex effectively internalizes in HeLa cancer cells as proven by fluorescence microscopy, shows a satisfactory biocompatibility in the dark, and induces about 50 % of cell mortality upon irradiation with visible light. The convergence of all these properties in one single complex makes the present host-guest ensemble an appealing candidate for further delevopment of photoactivatable nanoscaled systems addressed to photostimulated NO-based therapy. NO delivery today: A supramolecular host-guest complex, based on a rhodamine-labeled β-cyclodextrin conjugate and a tailored NO photodonor, effectively internalizes in cancer cells, can be easily mapped intracellularly due to its satisfactory red fluorescence emission, and induces about 50 % of cellular death under the exclusive control of visible light stimuli. Copyright
- Kandoth, Noufal,Malanga, Milo,Fraix, Aurore,Jicsinszky, Laszlo,Fenyvesi, Eva,Parisi, Tiziana,Colao, Ivana,Sciortino, Maria Teresa,Sortino, Salvatore
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- Strong supramolecular control over protein self-assembly using a polyamine decorated β-cyclodextrin as synthetic recognition element
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The supramolecular host molecule heptakis-[6-deoxy-6-(2-aminoethylsulfanyl) ]-β-cyclodextrin provides strong control over protein self-assembly in synthetic supramolecular protein constructs. Mono-functionalization of this modified β-cyclodextrin with a cysteine residue allows for site-selective synthetic conjugation to a protein and formation of a highly stable synthetic protein complex with a lithocholic acid conjugated protein as the interaction partner.
- Uhlenheuer, Dana A.,Milroy, Lech-Gustav,Neirynck, Pauline,Brunsveld, Luc
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- A versatile δ -aminolevulinic acid (ALA)-cyclodextrin bimodal conjugate-prodrug for PDT applications with the help of intracellular chemistry
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Grafting of aδ-aminolevulinic acid (1) moieties on the narrow periphery of a β-cyclodextrin (β-CD) derivative through hydrolysable bonds was implemented, in order to generate a water-soluble, molecular/drug carrier with the capacity to undergo intracellular transformation into protoporphyrin IX (PpIX), an endogenous powerful photosensitizer for photodynamic therapy (PDT). The water-soluble derivative 2 was prepared by esterifying aδ-azidolevulinic acid with heptakis(6-hydroxyethylamino-6-deoxy)-β- cyclodextrin, with an average degree of substitution, DS = 3. Delivery of water-soluble, colorless 2 to cells resulted in intense red fluorescence registered by confocal microscopy, evidently due to the engagement of the intracellular machinery towards formation of PpIX. Conjugate 2 was further complexed with a fluorescein-labeled model guest molecule which was successfully transported into the cells, thereby demonstrating the bimodal action of the derivative. The present work shows the versatility of CDs in smart applications and constitutes advancement to our previously shown PpIX-β-CD conjugation both in terms of water solubility and lack of aggregation. lack of aggregation.
- Aggelidou, Chrysie,Theodossiou, Theodossis A.,Gonalves, Antonio Ricardo,Lampropoulou, Mariza,Yannakopoulou, Konstantina
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- Nitric Oxide-Releasing Cyclodextrins
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A series of secondary amine-modified cyclodextrin (CD) derivatives was synthesized with diverse exterior terminal groups (i.e., hydroxyl, methyl, methoxyl, and primary amine). Subsequent reaction with nitric oxide (NO) gas under alkaline conditions yieldedN-diazeniumdiolate-modified CD derivatives. Adjustable NO payloads (0.6-2.4 μmol/mg) and release half-lives (0.7-4.2 h) were achieved by regulating both the amount of secondary amine precursors and the functional groups around the NO donors. The bactericidal action of these NO-releasing cyclodextrin derivatives was evaluated againstPseudomonas aeruginosa, a Gram-negative pathogen, with antibacterial activity proving dependent on both the NO payload and exterior modification. Materials containing a high density of NO donors or primary amines exhibited the greatest ability to eradicateP. aeruginosa. Of the materials prepared, only the primary amine-terminated heptasubstituted CD derivatives exhibited toxicity against mammalian L929 mouse fibroblast cells. The NO donor-modified CD was also capable of delivering promethazine, a hydrophobic drug, thus demonstrating potential as a dual-drug-releasing therapeutic.
- Jin, Haibao,Yang, Lei,Ahonen, Mona Jasmine R.,Schoenfisch, Mark H.
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- A persubstituted cationic β-cyclodextrin for chiral separations
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The applications of a novel polycationic derivative of β-cyclodextrin (β-CD), heptakis(6-hydroxyethylamino-6-deoxy-β-cyclodextrin) (β-CD-EA), as a chiral host-guest additive for the enantioseparation of various classes of chiral anionic analytes are presented. The cationic β-CD described in this paper is persubstituted with seven ethanolamine side arms at the primary rim of each cyclodextrin (CD) molecule. It is found that the electrophoretic mobility of β-CD-EA. can be adjusted to influence the chiral selectivity by changing the pH of the background electrolyte. Most of the observed CD capillary zone electrophoresis (CZE) separations of anionic drugs and herbicides were accomplished in the pH range of 4.0-7.0 with a reverse polarity configuration. At pH 5.0, enantioseparation of a mixture of three structurally related antiinflammatory agents (fenoprofen, flurbiprofen, and ibuprofen) was possible in about 30 min. However, other chiral acids, such as a series of phenoxypropionic acid herbicides and dansylated amino acids (glutamic acid and aspartic acids), were best separated at pH 6.0 or 7.0. An impressive separation of a mixture of six structurally related anionic herbicides [(±)-2-phenoxypropionic acid, (±)-2-(2-chlorophenoxy)propionic acid, (±)-2-(3-chlo-rophenoxy)propionic acid, (±)-2-(4-chlorophenoxy)propionic acid, (±)-2-(2,4-dichlorophenoxy)propionic acid, and (±)-2-(2,4,5-trichlorophenoxy)propionic acid] was achieved for the first time hi about 15 min during a single run with 20 mM β-CD-EA, The analytical applicability of this cationic CD molecule for chiral separations is discussed in detail.
- O'Keeffe, Frank,Shamsi, Shahab A.,Darcy, Raphael,Schwinte,Warner, Isiah M.
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- Mechanistic Understanding of a Robust and Scalable Synthesis of Per(6-deoxy-6-halo)cyclodextrins, Versatile Intermediates for Cyclodextrin Modification
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Cyclodextrin (CD) perfunctionalization reactions are challenging to study because they proceed through a number of regioisomeric intermediates, thus warranting creative approaches to understanding the reaction mechanism. Particularly useful perfunctionalization targets are per(6-deoxy-6-halo)cyclodextrins. Their standard synthesis entails selective SN2 halogenation at their primary alcohols using a Vilsmeier reagent, but this requires a strongly basic quench to unmask the Vilsmeier-capped secondary alcohols. Herein we present an alternative and simple acidic hydrolytic quench that utilizes existing HX in the end-of-reaction solution and requires only the addition of water. We performed a detailed mechanistic investigation of the new quench, and a central feature was the use of proton sponge to develop an 1H NMR titration method for HX in organic solvent. This method was used to both quantify and remove HX in the prequenched reaction solution. The HX-free prequenched solution enabled us to (1) identify sensitive intermediates during the quench, (2) quantify all of the reaction byproducts, and (3) determine that HX is critical for hydrolysis. We then studied the halogenation reaction, wherein the new acidic quench facilitated high-throughput experimentation, using mass spectrometry as well as Design of Experiments with automated reaction profiling. Through this, we were able to establish robustness and understand the complex effects of Vilsmeier equivalents and temperature on the reaction outcome.
- Zultanski, Susan L.,Kuhl, Nadine,Zhong, Wendy,Cohen, Ryan D.,Reibarkh, Mikhail,Jurica, Jon,Kim, Jungchul,Weisel, Lauren,Ekkati, Anil R.,Klapars, Artis,Gauthier, Donald R.,McCabe Dunn, Jamie M.
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supporting information
p. 597 - 607
(2020/10/12)
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- Mannosylated Poly(ethylene imine) Copolymers Enhance saRNA Uptake and Expression in Human Skin Explants
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Messenger RNA (mRNA) is a promising platform for both vaccines and therapeutics, and self-amplifying RNA (saRNA) is particularly advantageous, as it enables higher protein expression and dose minimization. Here, we present a delivery platform for targeted delivery of saRNA using mannosylated poly(ethylene imine) (PEI) enabled by the host-guest interaction between cyclodextrin and adamantane. We show that the host-guest complexation does not interfere with the electrostatic interaction with saRNA and observed that increasing the degree of mannosylation inhibited transfection efficiency in vitro, but enhanced the number of cells expressing GFP by 8-fold in human skin explants. Besides, increasing the ratio of glycopolymer to saRNA also enhanced the percentage of transfected cells ex vivo. We identified that these mannosylated PEIs specifically increased protein expression in the epithelial cells resident in human skin in a mannose-dependent manner. This platform is promising for further study of glycosylation of PEI and targeted saRNA delivery.
- Abdouni, Yamin,Becer, C. Remzi,Blakney, Anna K.,Bouton, Clément R.,Liu, Renjie,McKay, Paul F.,Shattock, Robin J.,Yilmaz, Gokhan
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p. 2482 - 2492
(2020/07/17)
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- NITRIC OXIDE-RELEASING CYCLODEXTRINS AS BIODEGRADABLE ANTIBACTERIAL SCAFFOLDS AND METHODS PERTAINING THERETO
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Disclosed herein are cyclodextrin molecules covalently modified to store and release nitric oxide, as well as methods of making and uses thereof. The covalently modified cyclodextrin molecules may be tailored, in several embodiments, to release nitric oxide in a controlled manner and are useful for reduction and/or eradication of bacteria and for the treatment of disease.
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(2019/10/01)
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- MODIFIED CYCLODEXTRINS FOR THE SELECTIVE SEQUESTRATION OF FENTANYL RELATED COMPOUNDS AND USES THEREOF
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Novel thioalkylcarboxylate-modified CDs and pharmaceutical compositions comprising these thioalkylcarboxylate-modified CDs are disclosed, as well as methods of using the disclosed thioalkylcarboxylate-modified CDs and pharmaceutical compositions thereof to neutralize or reduce undesired effects or symptoms associated with one or more fentanyl related compounds in a subject in need thereof. The use of the disclosed thioalkylcarboxylate-modified CDs to detect the presence of one or more fentanyl related compounds in a sample is also disclosed, which comprises contacting the sample with said thioalkylcarboxylate-modified CDs or a composition comprising these CDs.
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Paragraph 0080
(2019/01/10)
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- A convenient procedure for the formation of per(6-deoxy-6-halo) cyclodextrins using the combination of tetraethylammonium halide with [Et 2NSF2]BF4
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A convenient and efficient procedure for the regioselective halogenation of the primary alcohols of cyclodextrins using the reagent combination of tetraethylammonium halide with [Et2NSF2]BF4 is described. Georg Thieme Verlag Stuttgart New York.
- Liu, Xiaofeng,Cheng, Sen,Wang, Xiaolei,Xue, Weihua
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p. 3103 - 3105
(2013/12/04)
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- Monodisperse nanoparticles from self-assembling amphiphilic cyclodextrins: Modulable tools for the encapsulation and controlled release of pharmaceuticals
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Selective chemical functionalization of cyclodextrins (CDs) is a readily amenable methodology to produce amphiphilic macromolecules endowed with modulable self-organizing capabilities. Herein, the synthesis of well-defined amphiphilic CD derivatives, with a "skirt-type" architecture, that incorporate long-chain fatty esters at the secondary hydroxyl rim and a variety of chemical functionalities (e. g. iodo, bromo, azido, cysteaminyl or isothiocyanato) at the primary hydroxyls rim is reported. Nanoprecipitation of the new CD facial amphiphiles, or binary mixtures of them, resulted in nanoparticles with average hydrodynamic diameters ranging from 100 to 240 nm that were stable in suspension for several months. The precise size, zeta potential and topology of the nanoparticles are intimately dependent on the functionalization pattern at the CD scaffold. Highly efficient molecular encapsulation capabilities of poorly bioavailable drugs such as diazepam (DZ) were demonstrated for certain derivatives, the drug release profile being dependent on the type of formulation (nanospheres or nanocapsules). The efficiency and versatility of the synthetic strategy, together with the possibility of exploiting the reactivity of the functional groups at the nanoparticle surface, offer excellent opportunities to further manipulate the carrier capabilities of this series of amphiphilic CDs from a bottom-up approach.
- Mendez-Ardoy, Alejandro,Gomez-Garcia, Marta,Geze, Annabelle,Putaux, Jean-Luc,Wouessidjewe, Denis,Mellet, Carmen Ortiz,Defaye, Jacques,Fernandez, Jose M. Garcia,Benito, Juan M.
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scheme or table
p. 524 - 532
(2012/08/28)
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- A novel protocol for the regioselective bromination of primary alcohols in unprotected carbohydrates or glycosides
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The regioselective and efficient bromination of primary hydroxyl groups in unprotected carbohydrates or glycosides is successfully achieved by using (chloro-phenylthio-methylene)dimethylammoniumchloride (CPMA) in the presence of tetrabutylammonium bromide
- Xue, Weihua,Zhang, Lifen
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experimental part
p. 1429 - 1432
(2012/09/07)
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- An improved and alternative method for the preparation of per(6-bromo-6-deoxy)cyclodextrins
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A practical and efficient approach to the regioselective synthesis of per(6-bromo-6-deoxy)cyclodextrins is described. The method utilizes the easily accessible (chloro(phenylthio)methylene)dimethylammonium chloride (CPMA), circumventing disadvantages of earlier protocols. Georg Thieme Verlag Stuttgart. New York.
- Xue, Weihua,Zhang, Lifen
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experimental part
p. 3612 - 3614
(2011/12/16)
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- Clustering of Escherichia coli type-1 fimbrial adhesins by using multimeric heptyl α- D -mannoside probes with a carbohydrate core
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Heptyl α-D-mannoside (HM) is a strong inhibitor of the FimH lectin that mediates the initial adhesion of the uropathogenic Escherichia coli (E. coli) to the bladder cells. We designed a set of multivalent HM ligands based on carbohydrate cores with struct
- Almant, Mehdi,Moreau, Vincent,Kovensky, Jose,Bouckaert, Julie,Gouin, Sebastien G.
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body text
p. 10029 - 10038
(2011/10/18)
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- Novel polycarboxylated EDTA-type cyclodextrins as ligands for lanthanide binding: Study of their luminescence, relaxivity properties of Gd(iii) complexes, and PM3 theoretical calculations
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Novel EDTA-type cyclodextrin (CD) derivatives, AEDTA, BEDTA and GEDTA, bearing 6, 7 and 8 bis(carboxymethyl)amino (iminodiacetic acid) groups, respectively, were prepared, and their complexation with Eu(iii), Tb(iii) and Gd(iii) ions was studied. Luminescence titrations and mass spectrometry showed formation of multimetal complexes (AEDTA 2 to 3, BEDTA mainly 3 and GEDTA exactly 4 metal ions), whereas luminescence lifetime measurements revealed the presence of exchangeable water molecules. Semiempirical quantum mechanical calculations, performed by the PM3 method and assessed by DFT calculations on model ligands, indicated efficient multi-metal complexation, in agreement with the experiment. The structures showed coordination of the metal ions in the outer primary side of the CDs via 4 carboxylate O atoms, 2 N atoms and a glucopyranose O atom per metal ion. Coordination of water molecules was also predicted, in accordance with experimental results. Calculated bond lengths and angles were in agreement with literature experimental values of lanthanide complexes. Calculated energies showed that complex stability decreases in the order GEDTA > BEDTA > AEDTA. 1H NMR molecular relaxivity measurements for the Gd(iii) complexes of AEDTA, BEDTA or GEDTA in water afforded values 4 to 10 times higher than the relaxivity of a commercial contrast agent at 12 MHz, and 6 to 20 times higher at 100 MHz. Solutions of BEDTA and GEDTA Gd(iii) complexes in human blood plasma displayed relaxivity values at 100 MHz 7 and 12 times, respectively, higher than the commercial agent. MTT tests of the Gd(iii) complexes using human skin fibroblasts did not show toxicity. Attempts to supramolecularly sensitize the luminescence of the lanthanide complexes using various aromatic CD guests were ineffective, evidently due to large guest-metal distances and inefficient inclusion. The described lanthanide complexes, could be useful as contrast agents in MRI.
- Maffeo, Davide,Lampropoulou, Maria,Fardis, Michael,Lazarou, Yannis G.,Mavridis, Irene M.,Mavridou, Despoina A. I.,Urso, Elena,Pratsinis, Harris,Kletsas, Dimitris,Yannakopoulou, Konstantina
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scheme or table
p. 1910 - 1921
(2010/08/20)
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- Design and synthesis of a new series of amphiphilic peptide-β- cyclodextrins as phase transfer carriers for glucosamine
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A new series of amphiphilic β-cyclodextrins were designed and synthesized by grafting peptide chains on to all primary hydroxyl groups via ester bond formation. The desired amphiphilic structures have been produced from ester connection between the C-6 of β-cyclodextrin and the carboxyl group of N-acetylated resides: H2N-Leu-COOH, H2N-Leu-Gly-COOH, H2N-Leu-Gly-Leu-COOH, and H2N-Leu-Gly-Leu-Gly-COOH (3a-d). The synthetic pathway involves selective bromination of all primary hydroxyls of β-cyclodextrins and then substitution with the carboxylate moiety of the mentioned N-acetyl residues in the presence of DBU (1,8-diazabicyclo[5,4,0] undec-7-ene). The ability of the synthetic compounds for extraction and phase transfer of glucosamine, as a hydrophilic organic compound, was then studied. The results showed a considerable ability of these amphiphilic compounds for extraction and a selective tendency of 3c for phase transfer of glucosamine.
- Seyedi, Seyed Mohammad,Sadeghian, Hamid,Jabbari, Atena,Assadi, Amir,Momeni, Hamideh
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scheme or table
p. 6754 - 6760
(2010/10/01)
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- CYCLODEXTRIN DERIVATIVES AS POTENTIATORS FOR ANTIBIOTICS
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The invention provides a new class of antibiotics that are derivatives of cyclodextrin, which is a cyclic molecule comprising D-glucose units. In addition, the invention provides a method for potentiating the activity of antibiotic to inhibit the growth o
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(2009/06/27)
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- Synthesis, characterization, and remarkable biological properties of cyclodextrins bearing gnanidinoalkylamino and aminoalkylamino groups on their primary side
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The introduction of aminoalkylamino and guanidinoalkylamino substituents on the primary side of β-and γ-cyclodextrin (CDs) resulted in a series of novel compounds that were extensively characterized by NMR spectroscopy and mass spectrometry. Bromination of the primary side of β-and γ-CD, and reaction with neat alkylene diamines at a pressure of 7 atm afforded aminoalkylamino derivatives that were then guanylated at the primary amino group to give the corresponding guanidinoalkylamino-CDs. These compounds are water soluble and display pKa values that allow them to be mostly protonated at neutral pH; for example, pKa1-6.4 and pK a2-9.5 for the aminoethylamino-β-CD and pKa1-7.8 and pKa2-11.0 for the guanidinoethylamino-β-CD. The title CDs are rigid, cyclic α-D-glucopyranose oligomers (heptamers or octamers) with branches that resemble lysine and arginine side chains that enable multiple interactions with suitable substrates. Thus, they bear similarities to known cell-penetrating peptides. Indeed, the compounds were found to cross the membranes of HeLa cells and penetrate inside the cytoplasm quickly, the guadinylated ones within 15 min, as shown by fluorescence microscopy using fluorescein-labeled derivatives. The toxicity of the compounds, measured by performing MTT tests, ranged from 50 to 300 μM. Furthermore, some of the aminated CDs could facilitate the transfection of DNA expressing the green fluorescent protein (GFP) in HEK 293T cells, with effectiveness comparable to the commercial agent Lipofectamine 2000. Circular dichroism, atomic force microscopy and electrophoresis experiments confirmed the strong interaction of the compounds with DNA. Because of their carbohydrate, non-peptide nature the title compounds are not anticipated to be enzymatically labile or immunogenic, and thus they fulfill many of the criteria for non-hazardous transport vectors in biological and pharmaceutical applications.
- Mourtzis, Nikolaos,Paravatou, Maria,Mavridis, Irene M.,Roberts, Michael L.,Yannakopoulou, Konstantina
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scheme or table
p. 4188 - 4200
(2009/05/07)
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- Novel drug delivery compositions
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The present invention provides for a novel molecules useful for delivery of compounds to a mammal, more particularly for the intracellular delivery of nucleotides, nucleotide analogues or compounds with a heterocyclic base. Also provided for are novel therapeutic complexes comprising novel molecules complexed with nucleotide analogues or heterogeneous or homogenous oligomers comprised of nucleotide analogues.
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(2010/11/25)
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- Per(6-guanidino-6-deoxy)cyclodextrins: Synthesis, characterisation and binding behaviour toward selected small molecules and DNA
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Per(6-guanidino-6-deoxy)-cyclodextrins 4a, 4b and 4c are novel derivatives, resulting from homogeneous introduction of the guanidino group at the primary side of α-, β- and γ-cyclodextrins. The products were obtained from the corresponding amino derivatives, as direct guanidinylation of the known bromo-cyclodextrins provided mixtures. The new compounds were fully characterized by NMR spectroscopy and other analytical methods, and their interaction with guest molecules was studied. Strong complexation with 4-nitrophenyl phosphate (NPP) disodium salt was observed (Kbinding ~5 × 104 M-1), whereas the non-phosphorylated substrate nitrobenzene (NB) formed a very weak complex. 2D ROESY spectra revealed cavity inclusion in both cases, however the orientation of NPP was opposite to that of NB, such that the phosphate group is oriented toward the primary side facing the guanidine groups. The strong affinity of 4 towards the phosphorylated guest suggested that interaction with DNA was possible. The new compounds were found to completely inhibit the migration of ultra pure calf thymus DNA during agarose gel electrophoresis, whereas no effects were observed with guanidine alone or with the plain cyclodextrins. Further, the condensation of DNA into nanoparticles in the presence of 4b was demonstrated by atomic force microscopy, confirming strong electrostatic interaction between the biopolymer and the multicationic products 4. The strong guanidine-phosphate interactions between 4 and DNA were therefore attributed to the clustering of the guanidine groups in the primary area of the cyclodextrin. Cavity effects could not be assessed. This journal is The Royal Society of Chemistry.
- Mourtzis, Nikolaos,Eliadou, Kyriaki,Aggelidou, Chrysie,Sophianopoulou, Vassiliki,Mavridis, Irene M.,Yannakopoulou, Konstantina
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p. 125 - 131
(2008/03/14)
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- Bilayer vesicles of amphiphilic cyclodextrins: Host membranes that recognize guest molecules
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A family of amphiphilic cyclodextrins (6, 7) has been prepared through 6-S-alkylation (alkyl=n-dodecyl and n-hexadecyl) of the primary side and 2-O-PEGylation of the secondary side of α-, β-, and γ-cyclodextrins (PEG = poly(ethylene glycol)). These cyclodextrins form nonionic bilayer vesicles in aqueous solution. The bilayer vesicles were characterized by transmission electron microscopy, dynamic light scattering, dye encapsulation, and capillary electrophoresis. The molecular packing of the amphiphilic cyclodextrins was investigated by using small-angle X-ray diffraction of bilayers deposited on glass and pressure-area isotherms obtained from Langmuir monolayers on the air-water interface. The bilayer thickness is dependent on the chain length, whereas the average molecular surface area scales with the cyclodextrin ring size. The alkyl chains of the cyclodextrins in the bilayer are deeply interdigitated. Molecular recognition of a hydrophobic anion (adamantane carboxylate) by the cyclodextrin vesicles was investigated by using capillary electrophoresis, thereby exploiting the increase in electrophoretic mobility that occurs when the hydrophobic anions bind to the nonionic cyclodextrin vesicles. It was found that in spite of the presence of oligo(ethylene glycol) substituents, the β-cyclodextrin vesicles retain their characteristic affinity for adamantane carboxylate (association constant Ka = 7.1 × 103M-1), whereas γ-cyclodextrin vesicles have less affinity (Ka = 3.2 × 103M-1), and α-cyclodextrin or non-cyclodextrin, nonionic vesicles have very little affinity (Ka ≈100M -1). Specific binding of the adamantane carboxylate to β-cyclodextrin vesicles was also evident in competition experiments with β-cyclodextrin in solution. Hence, the cyclodextrin vesicles can function as host bilayer membranes that recognize small guest molecules by specific non-covalent interaction.
- Falvey, Patrick,Lim, Choon Woo,Darcy, Raphael,Revermann, Tobias,Karst, Uwe,Giesbers, Marcel,Marcelis, Antonius T. M.,Lazar, Adina,Coleman, Anthony W.,Reinhoudt, David N.,Ravoo, Bart Jan
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p. 1171 - 1180
(2007/10/03)
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- Synthesis of monofacially functionalized cyclodextrins bearing amino pendent groups
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Derivatives of the cyclodextrins, αCD, βCD, and ΥCD, in which all primary hydroxyls are substituted by amine pendant groups, may be synthesized efficiently from the per-6-bromo-6-deoxy-CD derivatives by direct reaction with amines. These ACD derivatives, which bear six, seven, or eight amine pendent groups, represent interesting biomimetic receptors and catalysts. The synthetic strategy relies on quantitative transformation and efficient purification as is demonstrated by preparation of 11 homogeneous ACD derivatives. The limitations of the synthesis and potential adaptations are illustrated by the synthesis of several more ACD derivatives to >95% purity. A synthetic route to a CD persubstituted with primary amine functionalities at the primary face, per-6-bromo-6-deoxy-CD, yields an alternative reagent to the simple per-6-bromo-6-deoxy-CD, which is more suitable for further synthetic transformations. The synthetic strategy is further adapted to preparation of a prototypical (6 + 1)-ACD derivative in which one primary position is substituted with a sulfide group and the remaining six primary face positions are substituted with amine pendent groups.
- Vizitiu, Dragos,Walkinshaw, Caroline S.,Gorin, Borio I.,Thatcher, Gregory R. J.
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p. 8760 - 8766
(2007/10/03)
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- An improved synthesis of 6-deoxyhalo cyclodextrins via halomethylenemorpholinium halides Vilsmeier-Haack Type reagents
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Per(6-bromo-6-deoxy)cyclomalto-hexaose, -heptaose, and -octaose and the corresponding per(6-chloro-6-deoxy) derivatives were prepared in high yield by reaction of bromomethylenemorpholinium bromide or chloromethylenemorpholinium chloride, respectively, with cyclomaltohexaose, cyclomaltoheptaose and cyclomaltooctaose in dimethylformamide.
- Chmurski, Kazimierz,Defaye, Jacques
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p. 7365 - 7368
(2007/10/03)
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- Direct synthesis of amphiphilic α-, β-, and γ-cyclodextrins
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The clean one step synthesis of the amphiphilic α-, β-, and γ-cyclodextrins starting from per-(6-bromo-6-deoxy)-α-, -β-, and -γ-cyclodextrins is described. The role of the lipophilic tail is played by various aryl groups (phenyl, p-bromophenyl, p-O-butoxyphenyl, p-pentylphenyl, and o-, m-, and p-nitrophenyl) linked by a thioether bridge to the position C-6 of each glucopyranose unit. The yields of the S-alkylation reactions were very high (85-95%).
- Chmurski, Kazimierz,Coleman, Antony W.,Jurczak, Janusz
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p. 787 - 796
(2007/10/03)
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- Efficient perfacial derivatization of cyclodextrins at the primary face
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Synthesis of thirteen cyclodextrin (CD) derivatives via the per-6-bromo-6-deoxy-CD is reported in order to demonstrate the efficiency and ease of perfacial functionalization of α, β and γCD employing a Vilsmeier-Haack reagent.
- Gorin, Boris I.,Riopelle, Richard J.,Thatcher, Gregory R. J.
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p. 4647 - 4650
(2007/10/03)
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- Synthesis of symmetrical cyclodextrin derivatives bearing multiple charges
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Several water-soluble symmetrical cyclodextrin derivatives bearing positively charged or negatively charged groups were synthesized to examine the possibility of obtaining stable electrostatically linked heterodimers in water.The positively charged specie
- Guillo, Frederique,Hamelin, Bertrand,Jullien, Ludovic,Canceill, Josette,Lehn, Jean-Marie,et al.
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p. 857 - 866
(2007/10/02)
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- Synthesis and photophysics of a water-soluble, naphthalene-containing β-cyclodextrin
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A water-soluble, naphthalene-containing β-cyclodextrin has been synthesized by reaction of 6-hydroxy-2-naphthalene sulfonic acid (disodium salt) with heptakis(6-bromo-6-deoxy)-β-cyclodextrin. Lifetime, fluorescence polarization, and solvent studies show the presence of mainly monomer fluorescence emission with a small amount of excimer. They also show that energy migration occurs. Quenching studies show that singlet energy transfer from the naphthalene substituents to a suitably included acceptor molecule can occur.
- Gravett, David M.,Guillet, James E.
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p. 5970 - 5974
(2007/10/02)
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- Multichromophoric Cyclodextrins. 1. Synthesis of O-Naphthoyl-β-cyclodextrins and Investigation of Excimer Formation and Energy Hopping
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The synthesis and photophysical properties of β-cyclodextrins bearing seven 2-naphthoyloxy chromophores in specific positions, either on the primary face or the secondary face, or 14 2-naphthoyloxy chromophores, seven on each face, are reported. These multichromophoric cyclodextrins are good models for the study of excitation energy migration among chromophores in well-defined positions. The investigation was performed in dichloromethane and in a mixture of ethanol and methanol that can form a glass at low temperature. The absorption spectra show that the interactions between chromophores in the ground state are weak, whereas the fluorescence spectra reveal the existence of excimers at room temperature but not at low temperature in a rigid glass. Further evidence of excimer formation is provided by the fluorescence decays. Since excimers act as energy traps, the energy hopping process was studied in a rigid glass at low temperature by steady-state and time-resolved fluorescence depolarization techniques. The steady-state anisotropy is found to be one seventh of the theoretical limiting anisotropy 0.4, which means that excitation energy hops between chromophores with essentially randomly oriented transition moments at a rate much higher than the chromophore intrinsic decay rate. Energy hopping is indeed very fast as shown by the fluorescence anisotropy decay which is at least as fast as the apparatus time resolution (a few tens of picoseconds).
- Berberan-Santos, Mário N.,Canceill, Josette,Brochon, Jean-Claude,Jullien, Ludovic,Lehn, Jean-Marie,Pouget, Jacques,Tauc, Patrick,Valeur, Bernard
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p. 6427 - 6436
(2007/10/02)
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- Improved preparation of hexakis(6-deoxy)cyclomaltohexaose and heptakis(6-deoxy)cyclomaltoheptaose
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Hexakis(6-deoxy)cyclomalto-hexaose and hexakis(6-deoxy)cyclomalto-hexaose were prepared by direct halogenation of cyclodextrins, with high yields. Direct bromination of cyclomaltohexaose for 15 hours gave a 93% yield.
- Baer,Vargas Berenguel,Shu,Defaye,Gadelle,Santoyo Gonzalez
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p. 307 - 314
(2007/10/02)
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