Azobenzene-Functionalised Core Cross-Linked Star Polymers and their Host–Guest Interactions

2014 ◽  
Vol 67 (1) ◽  
pp. 173 ◽  
Author(s):  
Shereen Tan ◽  
Edgar H. H. Wong ◽  
Qiang Fu ◽  
Jing M. Ren ◽  
Adrian Sulistio ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Benzoic Acid ◽  
Water Solubility ◽  
Star Polymers ◽  
Water Soluble ◽  
Hydroxyl Groups ◽  
Single Electron Transfer ◽  
One Pot ◽  
Radical Polymerisation ◽  
Soluble Poly

Water-soluble poly(2-hydroxyethyl acrylate) (PHEA)-based core cross-linked star polymers were efficiently synthesised with high macroinitiator-to-star-conversion (>95 %) in a one-pot system via single electron transfer-living radical polymerisation. The star polymers display excellent water solubility and the pendant hydroxyl groups provide a platform for facile post-functionalisation with various molecules. In demonstrating this, a photo-isomerisable molecule, 4-(phenylazo)benzoic acid was conjugated onto the preformed stars through partial esterification of the available hydroxyl groups (5–20 %). The azobenzene functionalised stars were subsequently employed to form reversible inclusion complexes with α-cyclodextrin.

Biocatalysis for Material Science and Drug Discoveries

2007 ◽  
Vol 1065 ◽  
Author(s):  
Ferdinando Francesco Bruno ◽  
Lynne A Samuelson ◽  
Subhalakshmi Nagarajan ◽  
Ramaswamy Nagarajan ◽  
Jayant Kumar
Keyword(s):  
Epithelial Cell ◽  
Cancer Cells ◽  
Water Solubility ◽  
Human Cancer ◽  
Water Soluble ◽  
Ambient Conditions ◽  
Inhibitory Effects ◽  
One Pot ◽  
Growth Inhibitory ◽  
Soluble Poly

ABSTRACTA novel biomimetic route for the synthesis of conducting homopolymers and copolymers from aniline, phenol, pyrrole and 3,4-ethylenedioxy-thiophene in the presence of a polyelectrolyte, such as polystyrene sulfonate (SPS) is presented. A poly(ethylene glycol) modified hematin (PEG-Hematin) and the enzyme horseradish peroxidase (HRP) were used to catalyze the copolymerization of different monomers. UV-vis, FTIR, XPS, TGA and electrical conductivity studies for all complexes indicated the presence of a stable and electrically conductive form of these polymers. Furthermore, the presence of a polyelectrolyte, such as SPS, in this complex provides a unique combination of properties such as processability and water-solubility. Additionally catechins, the active compounds found in green tea, were polymerized and found to exhibit very interesting anti-carcinogenic properties. Here we report a unique enzymatic approach for the synthesis of water-soluble poly(catechins) with enhanced stability and potent anti-proliferative effects on human cancer cells in vitro. Various stereoisomers of catechin [(+), (-), (±)] and (-)-epicatechin have been biocatalytically polymerized using HRP in ethanol/buffer mixtures. This one-pot biocatalytic polymerization is carried out in ambient conditions yielding water-soluble poly(catechins). These synthesized poly(catechins) were tested for their growth inhibitory properties using a variety of normal and cancerous human epithelial cell lines. The poly(catechins) exhibit statistically significant greater growth inhibitory effects when compared to the monomers and exhibited specificity, inhibiting the growth of breast, colorectal and esophageal cancer cells while having little effect on normal epithelial cell growththus achieving a high therapeutic ratio. The synthesis, characterization and the growth inhibitory effects of these novel water-soluble poly(catechins) will also be presented.

Reversal of Polarity by Catalytic SET Oxidation: Synthesis of Azabicyclo[m.n.o]alkanes via Chemoselective Reduction of Amidines

2021 ◽  
Author(s):  
Sundarababu Baskaran ◽  
Kirana D V ◽  
Kanak Kanti Das
Keyword(s):  
Electron Transfer ◽  
Stereoselective Synthesis ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Catalytic Method ◽  
One Pot ◽  
Oxidative System ◽  
Oxidation Synthesis

A one-pot catalytic method has been developed for the stereoselective synthesis of cyclopropane-fused cyclic amidines using CuBr2/K2S2O8 as an efficient single electron transfer (SET) oxidative system. The generality of this...

Sulfonyl esters 6. Elucidation of the first sequence in the Trithioorthoformate Reaction

1995 ◽  
Vol 73 (3) ◽  
pp. 444-452 ◽  
Author(s):  
James Clayton Baum ◽  
Bradley Eugene Black ◽  
Laura Precedo ◽  
John Edward Goehl ◽  
Richard Francis Langler
Keyword(s):  
Electron Transfer ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Computational Results ◽  
One Pot ◽  
The One ◽  
Sulfonate Ester

The one-pot conversion of a mercaptan and an aryl methanesulfonate into a trithioorthoformate is described. The intermediacy of a sulfide-sulfonate ester is firmly established. Experimental and computational results permit the formulation of a possible pathway for the formation of the intermediate sulfide-sulfonate ester. Keywords: single electron transfer, sulfonate esters, sulfide-sulfonate esters.

Water-Soluble Poly(vinylferrocene)-b-Poly(ethylene oxide) Diblock and Miktoarm Star Polymers

2012 ◽  
Vol 45 (8) ◽  
pp. 3409-3418 ◽  
Author(s):  
Christoph Tonhauser ◽  
Markus Mazurowski ◽  
Matthias Rehahn ◽  
Markus Gallei ◽  
Holger Frey
Keyword(s):  
Ethylene Oxide ◽  
Star Polymers ◽  
Water Soluble ◽  
Poly Ethylene Oxide ◽  
Miktoarm Star ◽  
Poly Ethylene ◽  
Soluble Poly

Sulfonyl esters 7. The second and third sequences in the Trithioorthoformate Reaction

1996 ◽  
Vol 74 (9) ◽  
pp. 1638-1648 ◽  
Author(s):  
Kashyapa Ananda Ginige ◽  
John Edward Goehl ◽  
Richard Francis Langler
Keyword(s):  
Electron Transfer ◽  
Key Words ◽  
Single Electron ◽  
Single Electron Transfer ◽  
One Pot ◽  
The One ◽  
Sulfonate Ester

A previous report has established the intermediacy of a sulfide-sulfonate ester in the one-pot conversion of an aryl mercaptan and a sulfonate ester into the corresponding trithioorthoformate. This report describes evidence for the sequential intermediacy of a bissulfide-sulfonate ester and a dithiosulfène in the conversion of the sulfide-sulfonate ester into the trithioorthoformate. A new sulfonate ester is shown to give the highest yield of trithioorthoformate. Key words: single electron transfer, sulfonate esters, sulfenes.

Applications of ytterbium(II) reagent as Grignard reagent and single electron transfer reagent in the synthesis of 3-substituted-2-oxindoles

Synthesis ◽  
2021 ◽  
Author(s):  
Pengkai Wang ◽  
yan xu cao ◽  
Songlin Zhang
Keyword(s):  
Electron Transfer ◽  
Grignard Reagent ◽  
Nucleophilic Reagent ◽  
Point Of View ◽  
Single Electron ◽  
Single Electron Transfer ◽  
One Pot ◽  
First Time ◽  
Isatin Derivatives

The utilities of ytterbium(II) reagent, both as nucleophilic reagent and single electron transfer reagent in the reaction of isatin derivatives with ytterbium(II) reagent are reported for the first time in this paper. From a synthetic point of view, a general, efficient, and experimentally simple one-pot method for preparation of 3-substituted-2-oxindoles was developed.

scholarly journals Distinct Binding Dynamics, Sites and Interactions of Fullerene and Fullerenols with Amyloid-β Peptides Revealed by Molecular Dynamics Simulations

2019 ◽  
Vol 20 (8) ◽  
pp. 2048 ◽  
Author(s):  
Zhiwei Liu ◽  
Yu Zou ◽  
Qingwen Zhang ◽  
Peijie Chen ◽  
Yu Liu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Water Solubility ◽  
Binding Free Energy ◽  
Critical Role ◽  
Amyloid Β ◽  
Fullerene C60 ◽  
Water Soluble ◽  
Hydroxyl Groups ◽  
Dynamics Simulations

The pathology Alzheimer’s disease (AD) is associated with the self-assembly of amyloid-β (Aβ) peptides into β-sheet enriched fibrillar aggregates. A promising treatment strategy is focused on the inhibition of amyloid fibrillization of Aβ peptide. Fullerene C60 is proved to effectively inhibit Aβ fibrillation while the poor water-solubility restricts its use as a biomedicine agent. In this work, we examined the interaction of fullerene C60 and water-soluble fullerenol C60(OH)6/C60(OH)12 (C60 carrying 6/12 hydroxyl groups) with preformed Aβ40/42 protofibrils by multiple molecular dynamics simulations. We found that when binding to the Aβ42 protofibril, C60, C60(OH)6 and C60(OH)12 exhibit distinct binding dynamics, binding sites and peptide interaction. The increased number of hydroxyl groups C60 carries leads to slower binding dynamics and weaker binding strength. Binding free energy analysis demonstrates that the C60/C60(OH)6 molecule primarily binds to the C-terminal residues 31–41, whereas C60(OH)12 favors to bind to N-terminal residues 4–14. The hydrophobic interaction plays a critical role in the interplay between Aβ and all the three nanoparticles, and the π-stacking interaction gets weakened as C60 carries more hydroxyls. In addition, the C60(OH)6 molecule has high affinity to form hydrogen bonds with protein backbones. The binding behaviors of C60/C60(OH)6/C60(OH)12 to the Aβ40 protofibril resemble with those to Aβ42. Our work provides a detailed picture of fullerene/fullerenols binding to Aβ protofibril, and is helpful to understand the underlying inhibitory mechanism.

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