- Detecting a transition-metal ammine at tailored surfaces
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The fabrication of surfaces by forming Langmuir films, which incorporate amphiphiles containing hydrophilic 18-crown-6 (18C6) derivatives, at a gas/water interface is described. These Langmuir films can be transferred to a hydrophobised quartz crystal microbalance (QCM), using the Langmuir-Blodgett technique. The QCM response has been measured in aqueous solution as a function of the concentration of the transition metal complex [Co(NH3)6]Cl3 which was injected into a vial in which the film-coated QCM had been immersed. By comparing various surfaces covered with hydrophilic polyether and hydroxy functions and hydrophobic methyl groups, and by varying the composition of the films so as to increase the separation between the 18C6 macrocycles, it has been demonstrated that surfaces can be tailored that will enhance the binding of the [Co(NH3)6]3+ trications.
- Iqbal, Sayeedha,Kremer, Felix J.B.,Ringsdorf, Helmut,Steinbeck, Martin,Stoddart, J. Fraser,Shen, Jie,Tinker, Nigel D.
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- Monodisperse oligoethylene glycols modified Camptothecin, 10-Hydroxycamptothecin and SN38 prodrugs
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Camptothecin, which represents a class of natural products with high anticancer activity, suffers low water solubility which hampers its clinic application. To address this issue, monodisperse polyethylene glycols were employed to modify this class of natural products, including Camptothecin, 10-Hydroxycamptothecin, and SN38. Through selective modification with a series of monodisperse polyethylene glycols, 31 Camptothecin derivatives, including 9 ethers and 22 carbonates, were prepared using a macrocyclic sulfate-based strategy with high efficacy. Monodisperse polyethylene glycols modification provided the Camptothecin derivatives with high purity and fine-tunable water solubility. Through the physicochemical and biological assays, a few novel prodrugs with good solubility, cytotoxicity, and valuable drug release profile were identified as promising anticancer drug candidates.
- Deng, Tao,Mao, Xianglan,Xiao, Yan,Yang, Zhigang,Zheng, Xing,Jiang, Zhong-Xing
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supporting information
p. 581 - 584
(2019/01/04)
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- Monodisperse polyethylene glycol “brushes” with enhanced lipophilicity, and thermo and plasma stability
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A convenient strategy was developed for highly branched and multifunctionalized peptidic monodisperse polyethylene glycol “brushes”, which exhibit remarkable physicochemical and biological properties and potential as versatile biomaterials.
- Li, Yu,Wang, Xuemeng,Chen, Yongping,Yang, Zhigang,Jiang, Zhong-Xing
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supporting information
p. 1895 - 1898
(2019/05/02)
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- Monodisperse oligoethylene glycols modified Propofol prodrugs
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The low water solubility of Propofol resulted in complicated formulation and adverse effects during its clinical application. To improve its water solubility and maintain its anesthetic effects, Propofol prodrugs with monodisperse oligoethylene glycols as solubility enhancer were designed and synthesized. Monodisperse oligoethylene glycols enable the concise manipulation of water solubility, biocompatibility and anesthetic effects. Through the physicochemical and biological assay, a few water soluble prodrugs of Propofol were identified as promising anesthetic to overcome the drawbacks associated with Propofol.
- Deng, Tao,Mao, Xianglan,Li, Yu,Bo, Shaowei,Yang, Zhigang,Jiang, Zhong-Xing
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p. 3502 - 3505
(2018/10/15)
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- INHIBITORS OF HEPATITIS C VIRUS POLYMERASE
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The present invention provides, among other things, compounds represented by the general Formula I: (I) and pharmaceutically acceptable salts thereof, wherein L and A (and further substituents) are as defined in classes and subclasses herein and compositions (e.g., pharmaceutical compositions) comprising such compounds, which compounds are useful as inhibitors of hepatitis C virus polymerase, and thus are useful, for example, as medicaments for the treatment of HCV infection.
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- Design and Synthesis of Fluorinated Amphiphile as 19F MRI/Fluorescence Dual-Imaging Agent by Tuning the Self-Assembly
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Both 19F MRI and optical imaging are powerful noninvasive molecular imaging modalities in biomedical applications. To integrate these two complementary imaging modalities, the design and synthesis of a novel 19F MRI/fluorescence dual-modal imaging agent is reported herein. Through Sonogashira coupling reaction between the fluorinated phenylacetylene and 1,2,4,5-tetraiodobenzene, a fluorophore with 48 symmetrical fluorines at its periphery was constructed with high efficacy. High aqueous solubility was achieved by PEGylation of the fluorophore with monodisperse PEGs. However, an unexpected self-assembly of the PEGylated amphiphilic fluorophore in water "turned off" the 19F NMR signal. However, hydrogenation of the triple bonds or introduction of branched monodisperse PEGs was able to efficiently tune the self-assembly, resulting in the "turning on" of the 19F NMR signal. One of these amphiphiles combines the advantages of label-free fluorescence, high 19F MRI sensitivity, biocompatibility, and excellent aqueous solubility. The results demonstrate the great potential of such amphiphiles for real-time 19F MRI and fluorescence dual-modality imaging.
- Bo, Shaowei,Song, Cong,Li, Yu,Yu, Weijiang,Chen, Shizhen,Zhou, Xin,Yang, Zhigang,Zheng, Xing,Jiang, Zhong-Xing
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p. 6360 - 6366
(2015/06/30)
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- Highly efficient synthesis of monodisperse poly(ethylene glycols) and derivatives through macrocyclization of oligo(ethylene glycols)
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A macrocyclic sulfate (MCS)-based approach to monodisperse poly(ethylene glycols) (M-PEGs) and their monofunctionalized derivatives has been developed. Macrocyclization of oligo(ethylene glycols) (OEGs) provides MCS (up to a 62-membered macrocycle) as versatile precursors for a range of monofunctionalized M-PEGs. Through iterative nucleophilic ring-opening reactions of MCS without performing group protection and activation, a series of M-PEGs, including the unprecedented 64-mer (2850Da), can be readily prepared. Synthetic simplicity coupled with versatility of this new strategy may pave the way for broader applications of M-PEGs. Macrocycles make synthesis easier: Convenient macrocyclization of the OEGs provides versatile macrocyclic sulfates. These compounds are cornerstones for both monofunctionalization of OEGs and highly efficient synthesis of monodisperse PEGs and derivatives, including an unprecedented 64-mer.
- Zhang, Hua,Li, Xuefei,Shi, Qiuyan,Li, Yu,Xia, Guiquan,Chen, Long,Yang, Zhigang,Jiang, Zhong-Xing
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p. 3763 - 3767
(2015/03/18)
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- Synthesis, characterization and spectroscopic properties of water soluble coumarins substituted with oligomeric alkoxy functions
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Novel water soluble robust fluorescent coumarins substituted with oligomeric alkoxy functions were synthesized by incorporating the Blaise reaction in the key step. Mono-methylated oligomeric polyethylene glycols were subjected to a three step protocol, namely (i) Michael addition to acrylonitrile, (ii) Blaise reaction with ethyl bromoacetate and (iii) condensation with 4-N,N-diethylamino-2-hydroxybenzaldehyde to give fluorescent water soluble coumarins. Water solubility of the coumarins increased with the number of oxygen atoms in the side chain. However, even the most water soluble coumarin in this series can be readily extracted out of water with organic solvents like dichloromethane or ethyl acetate. Both absorption and emission spectra, recorded in four solvents, namely, hexane (non-polar), ethyl acetate (moderately polar), methanol (polar protic) and water (highly polar and protic) displayed a bathochromic shift of the absorption (Δλmax ≈ 25 nm) and emission (Δλmax ≈ 57 nm) bands with increasing solvent polarity. The Δλmax of emission is more pronounced than the Δλmax of absorption, which indicates intramolecular charge-transfer (ICT) is less in the ground state compared to the excited state. Emission spectra recorded in these four solvents showed that fluorescent intensity is maximum in ethyl acetate.
- Surya Prakash Rao,Babu, Mohan,Desai, Avinash
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p. 11064 - 11072
(2014/03/21)
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- Polyethylene glycol-based homologated ligands for nicotinic acetylcholine receptors
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A homologous series of polyethylene glycol (PEG) monomethyl ethers were conjugated with three ligand series for nicotinic acetylcholine receptors. Conjugates of acetylaminocholine, the cyclic analog 1-acetyl-4,4-dimethylpiperazinium, and pyridyl ether A-84543 were prepared. Each series was found to retain significant affinity at nicotinic receptors in rat cerebral cortex with tethers of up to six PEG units. Such compounds are hydrophilic ligands which may serve as models for fluorescent/affinity probes and multivalent ligands for nAChR.
- Scates, Bradley A.,Lashbrook, Bethany L.,Chastain, Benjamin C.,Tominaga, Kaoru,Elliott, Brandon T.,Theising, Nicholas J.,Baker, Thomas A.,Fitch, Richard W.
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supporting information; experimental part
p. 10295 - 10300
(2009/04/12)
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- Poly(ethylene glycol)-based stable isotope labeling reagents for the quantitative analysis of low molecular weight metabolites by LC-MS
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Stable isotope labeling (SIL) in combination with liquid chromatography-mass spectrometry is one of the most widely used quantitative analytical methods due to its sensitivity and ability to deal with extremely complex biological samples. However, SIL methods for metabolite analysis are still often limited in terms of multiplexing, the chromatographic properties of the derivatized analytes, or their ionization efficiency. Here we describe a new family of reagents for the SIL of primary amine-containing compounds based on pentafluorophenyl-activated esters of 13C-containing poly(ethylene glycol) chains (PEG) that addresses these shortcomings. A sequential buildup of the PEG chain allowed the introduction of various numbers of 13C atoms opening extended multiplexing possibilities. The PEG derivatives of rather hydrophilic molecules such as amino acids and glutathione were successfully retained on a standard C18 reversed-phase column, and their identification was facilitated based on m/z values and retention times using extracted ion chromatograms. The mass increase due to PEG derivatization moved low molecular weight metabolite signals out of the often noisy, low m/z region of the mass spectra, which resulted in enhanced overall sensitivity and selectivity. Furthermore, elution at increased retention times resulted in efficient electrospray ionization due to the higher acetonitrile content in the mobile phase. The method was successfully applied to the quantification of intracellular amino acids and glutathione in a cellular model of human lung epithelium exposed to cigarette smoke-induced oxidative stress. It was shown that the concentration of most amino acids increased upon exposure of A549 cells to gas-phase cigarette smoke with respect to air control and cigarette smoke extract and that free thiol-containing species (e.g., glutathione) decreased although disulfide bond formation was not increased. These labeling reagents should also prove useful for the labeling of peptides and other compounds containing primary amine functionalities.
- Abello, Nicolas,Geurink, Paul P.,Van Der Toorn, Marco,Van Oosterhout, Antoon J. M.,Lugtenburg, Johan,Van Der Marel, Gijs A.,Kerstjens, Huib A. M.,Postma, Dirkje S.,Overkleeft, Hermen S.,Bischoff, Rainer
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experimental part
p. 9171 - 9180
(2009/06/20)
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- Synthesis of thermosensitive water-soluble polystyrenics with pendant methoxyoligo(ethylene glycol) groups by nitroxide-mediated radical polymerization
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Nitroxide-mediated radical polymerizations of 4-vinylbenzyl methoxytris(oxyethylene) ether (TEGSt), 4-vinylbenzyl methoxytetrakis(oxyethylene) ether (TrEGSt), and 4-vinylbenzyl methoxypentakis-(oxyethylene) ether (PEGSt) were carried out at 120°C using 2,2,5-trimethyl-3-(1-phenylethoxy)-4-phenyl-3-azahexane as initiator. Kinetics study and gel permeation chromatography analysis showed that the polymerizations were living processes yielding polymers with controlled molecular weights and narrow molecular weight distributions. The polymers can be dissolved in water forming transparent solutions and undergo phase transitions when the temperature is above a critical point. The cloud points of the homopolymers of TEGSt, TrEGSt, and PEGSt were around 13, 39, and 55°C, respectively, which were also supported by variable temperature 1H NMR spectroscopy analysis. The high level of alkoxyamine chain end retention allowed the synthesis of diblock copolymers with low polydispersities (1H NMR studies indicated that the diblock copolymers undergo phase transition in water at a temperature between the cloud points of the two corresponding homopolymers.
- Zhao, Bin,Li, Dejin,Hua, Fengjun,Green, Derrick R.
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p. 9509 - 9517
(2008/02/01)
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- Oligosaccharide synthesis by affinity separation based on molecular recognition between podand ether and ammonium ion
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We previously reported a new synthetic methodology termed 'synthesis based on affinity separation' (SAS) in which the desired tagged compound was separated from the reaction mixture by solid-phase extraction using specific molecular recognition of the tag. The interaction between a crown ether tag and polymer-supported ammonium ion was initially employed for SAS. In the present study, a new SAS method using a podand-type tag, a pseudo-benzo-31-crown-10 structure, was elaborated for oligosaccharide synthesis. The podand tag was much easier to synthesize than the corresponding crown ether. The podand moiety was attached to the monosaccharide residue via appropriate linkers. After glycosylation of the tagged monosaccharide with a glycosyl donor, the reaction mixture was subjected to the affinity separation. The desired compounds possessing the podand tag were effectively separated by the affinity between the podand and the ammonium ion. Continuous flow synthesis by integration of a microreactor and the present SAS system was applied for high throughput oligosaccharide synthesis. Georg Thieme Verlag Stuttgart.
- Fukase, Koichi,Takashina, Mamoru,Hori, Yumiko,Tanaka, Daizo,Tanaka, Katsunori,Kusumoto, Shoichi
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p. 2342 - 2346
(2007/10/03)
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- Network single ion conductors based on comb-branched polyepoxide ethers and lithium bis(allylmalonato)borate
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The synthesis of network single ion conductors to obtain single ion conductors with high ambient temperature conductivity and mechanical strength is discussed. The single ion conductors were based on comb-branched polyepoxide ethers and lithium (Li) bis(allylmelonato)borate. The single ion conductors possessed good mechanical strength due to the formation of network structure and the Li/Li symmetric cell cycling showed no concentration polymerization. The results show that the backbone structure of the polyepoxides contributes to the total ionic conductivity and it increases with the increasing side chain length.
- Sun, Xiao-Guang,Kerr, John B.,Reeder, Craig L.,Liu, Gao,Han, Yongbong
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p. 5133 - 5135
(2007/10/03)
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- Synthesis and physical properties of poly(phenylene vinylene)s having oligo(ethylene oxide) in the side chain
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Oligo(ethylene oxide) chains were introduced into the phenyl ring of the poly(phenylene vinylene) (PPV) derivatives to obtain electronic and ionic conductive liquid crystalline PPV derivatives. Thermal decomposition of all PPV derivatives occurred before isotropic melt. A typical texture of the liquid crystalline phase was not shown but birefringence was observed below the thermal decomposition temperature. Exhibition of a smectic phase for the polymers having triethylene or tetraethylene oxide chains was supported by X-ray measurements. Electronic conductivity of the PPV derivatives doped with I 2 and ionic conductivity of the mixture of these polymers and LiClO4 were also discussed.
- Mihara, Takashi,Yada, Takahiro,Koide, Naoyuki
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p. 421/[1463]-437/[1479]
(2007/10/03)
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- Convergent synthesis of AB2-AB3 hybrid-type of amphiphilic oligoethyleneoxy-modified poly(benzyl ether) dendrons
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A new class of AB2-AB3 hybrid-type of amphiphilic oligoethyleneoxy-modified poly(benzyl ether) dendrons has been synthesised by a convergent route.
- Tang, Dai-Hua,Fan, Qing-Hua
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p. 698 - 699
(2007/10/03)
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- Synthesis of Monodisperse Perfluoroalkyl-Oxyethylene Surfactants with Methoxy Capping: Surfactants of High Chemical Inertness
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Monodisperse fluoroalkyl non-ionic surfactants with a methoxy group capping the hydrophilic head, and having a high chemical inertness and surface properties typical of perfluorinated non-ionic surfactants, have been synthesized.
- Selve, Claude,Achilefu, Samuel
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p. 911 - 912
(2007/10/02)
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- 246. Monofunctional (Dimethylamino)silane as Silylating Agent
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The reaction of triorganyl(dimethylamino)silanes with surface-hydrated silicon dioxide has been studied.These silylating agents are easy to prepare from the corresponding chloro or bromosilanes with dimethylamine.The resulting products are thermally stable and relatively volatile.Reaction with surface-hydrated silicon-dioxide preparations at a50-250 deg C for 170 h yields a dense grafted layer.However, with (dimethylamino)silanes having strongly polar substituents, a retreatment of the surface-modified silica seems to be necessary in order to attain maximum coverage.
- Szabo, Katalin,Le Ha, Ngoc,Schneider, Philippe,Zeltner, Peter,sz. Kovacs, Ervin
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p. 2128 - 2142
(2007/10/02)
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- Neutral Ligands with Surfactant-Type Structure - Synthesis, Complexation, and Ion Transfer
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New lipophilic neutral ligands which combine crown ether and podand characteristics with structural features of surfactants (cf. formulas 1-12, 16-26) were synthesized.Their complexation behaviour was studied, their solid-to-liquid and liquid-to-liquid phase transfer properties as well as their efficiency in ion transport across a liquid model membrane.Crystalline stoichiometric complexes of the cycles 2a-4a and of 3e with NaSCN, Ba(SCN)2, and BaI2 can be isolated.Among the noncyclic representatives a crystalline complex is obtained only from 11 with BaI2.The ligand 8d behaves in aqueous solution as a typical surfactant showing micelle formation and cloud point.
- Weber, Edwin
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p. 770 - 801
(2007/10/02)
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- Veretherungen von Diolen, Triolen und Hydroxycarbonsaeurederivaten ueber Thallium(I)-alkoholate. Eine neue Variante der Williamson-Reaktion
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The etherifications listed in tables 1 and 2 are achieved by converting hydroxy-derivatives, which contain additional oxygen functions, into thallium(I) alkoxides with thallium ethoxide, and treatment with haloalkanes.The scope and limitations of the method are discussed.
- Kalinowski, Hans-Otto,Crass, Gerhard,Seebach, Dieter
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p. 477 - 487
(2007/10/02)
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- Association of Alkali and Alkaline Earth Cations with Benzo-18-crown-6 and Its Neutral and Negatively Charged Acyclic Analogues in Methanol Solution
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The effect of added alkali (Li, Na, K, Rb, and Cs) and alkaline earth (Ca, Sr, and Ba) metal bromides on the acid dissociation of o-hydroxyphenyl 3,6,9,12-tetraoxatridecyl ether (ArOH) in MeOH at 25 deg C has been investigated spectrophotometrically over a wide range of salt concentration.Except for the Li ion, all the investigated salts increased significantly the apparent acidity of ArOH in a way that could be accounted for by the formation of 1:1 addition compounds of the metal cations with both ArOH and its conjugate base ArO-.A proper analysis of the experimental data yielded the equilibrium constants for the formation of the associated species.Complexation of the given cations by benzo-18-crown-6 (C) was also studied spectrophotometrically under the same conditions.The set of equilibrium constants here reported constitute a proper basis for a systematic discussion of the ligation properties of sexadentate ligands with oxygen donors belonging to different structural types.The cyclic ligand C binds cations more strongly than does its open-chain analogue ArOH.The magnitude of the macrocyclic effect is found to be mainly determined by the size of the cation, rather than by its charge.On the other hand, the advantage of the anionic ligand ArO- over ArOH is highly sensitive to the charge of the cation with little or no dependence upon its size.This suggests that direct contact between the oxide ion and the cation is lacking in the ArO-Mz+ species.
- Ercolani, Gianfranco,Mandolini, Luigi,Masci, Bernardo
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p. 7484 - 7489
(2007/10/02)
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