Advertisement

Topics

PubMed Journal Database | Angewandte Chemie (International ed. in English) RSS

03:50 EDT 25th May 2019 | BioPortfolio

The US National Library of Medicine and National Institutes of Health manage PubMed.gov which comprises of more than 29 million records, papers, reports for biomedical literature, including MEDLINE, life science and medical journals, articles, reviews, reports and  books.

BioPortfolio aims to cross reference relevant information on published papers, clinical trials and news associated with selected topics - speciality.

For example view all recent relevant publications on Epigenetics and associated publications and clincial trials.

Showing PubMed Articles 1–25 of 3,400+ from Angewandte Chemie (International ed. in English)

Gold-catalyzed 4+2-Annulations of Dienes with Nitrosoarenes that Serve as 4-π-donors to Enable Nitroso-Povarov Reactions.

This work reports the first success of the nitroso-Povarov reactions involving gold-catalyzed [4+2]-annulations of nitrsoarenes with substituted cyclopentadienes. In this catalytic sequence, nitrosoarenes presumably attack at gold-π-dienes via a 1,4-addition pathway, generating allylgold nitrosonium intermediates to complete an intramolecular cyclization. Acyclic dienes are also applicable substrates, but affording oxidative nitroso-Povarov products.

Chiral resolution using supramolecular templated mesostructured materials.

Chiral resolution using non-functionalized mesoporous particles is demonstrated for a variety of enantiomeric pairs. This is achieved through the use of supramolecular templated silica materials prepared with guanosine monophosphate (NGM-1) and folic acid (NFM-1) which enable direct chiral transcription onto the surface of the mesopores after solvent extraction and post calcination of the template. The chiral selectivity and kinetics of the mesoporous materials are measured by circular dichroism (CD) spectr...

The Persistent Radical Effect in Organic Synthesis.

Radical-radical couplings are mostly nearly diffusion controlled processes. Therefore, the selective cross-coupling of two different radicals is challenging and not a synthetically valuable process. However, if the radicals have a different lifetime and if they are generated at equal rates, cross-coupling will become the dominant process. This high cross-selectivity is based on a kinetic phenomenon called the persistent radical effect (PRE). In this review, an explanation of the PRE supported by simulations...

Highly Efficient CO₂ Utilization via Novel Aqueous Zn or Al-CO₂ Systems for H₂ and Electricity Production.

Atmospheric carbon dioxide (CO2) has increased from 278 to 408 parts per million (ppm) over the industrial period and has critically impacted on climate changes. In response to this crisis, carbon capture, utilization, and storage/sequestration technologies have been recently studied. So far, however, the economic feasibility of the existing conversion technologies is still inadequate due to sluggish CO2 conversion. Herein, we report an aqueous zinc- and aluminum-CO2 system that utilizes an acidity from spo...

Swelling-Induced Chain Stretching Enhances Hydrolytic Degrafting of Hydrophobic Polymer Brushes in Organic Media.

Hydrophilic polymer brushes grown via surface-initiated polymerization from silicon oxide surfaces can detach or degraft in aqueous media. Degrafting of these chain end-tethered polymers is believed to involve hydrolysis of bonds at the polymer - substrate interface. Degrafting so far has not been reported for hydrophobic polymer brushes in non-aqueous media. This study has investigated the degrafting and swelling properties of poly(tert-butyl methacrylate) (PtBMA) brushes in different water-miscible, organ...

Phase Transformation Behavior of a Two-Dimensional Zeolite.

Understanding the molecular-level mechanisms of phase transformation in solids is of fundamental interest for beneficial industrial technologies of functional materials like zeolites. Two-dimensional (2D) zeolites, when used as shape-selective catalysts, can have the advantage of an improved access to catalytically active sites and a shortened diffusion length in comparison with their 3D analogues. However, few materials are known to maintain both their intralayer microporosity and structure during calcinat...

The Chemistry, Biology and Modulation of Ammonium Nitrification in Soil.

One to two percent of the world's energy is consumed for the production of ammonia from hydrogen and nitrogen gas. Ammonia is used as a fertilizer ingredient for agriculture and distributed in the environment on an enormous scale to promote crop growth in intensive farming. Only 30-50% of the nitrogen applied is assimilated by crop plants; the remaining 50-70% goes into biological processes such as nitrification by soil-microbial metabolism. This leads to an imbalance in the global nitrogen cycle and higher...

A safe and efficient strategy for in vivo rapid eliminating blood lead based on capture-fix-separate mechanism.

Blood lead poisoning has become an important problem because of its serious effects on human health. Yet a solution has not become apparent due to the incomplete understanding of existing state of lead ions in blood. Based on the fact that most of blood lead binds to hemoglobin (Hb) in red blood cells (RBCs), identifying and capturing lead-contaminated Hb in RBCs is rather important. In this work, one blood lead magnetic remover with hyperbranched poly(amido amine)s (HPAM) as template/co-adsorbent and core-...

Facile Generation of Polymer-Alloy Hybrid Layer towards Dendrite-free Lithium Metal Anode with Improved Moisture Stability.

Lithium (Li) metal anode is recognized as the most promising next-generation anode material for high-energy storage batteries. However, the lithium dendrites lead to irreversible capacity decay in lithium metal batteries (LMBs). Besides, strict assembly environment conditions of LMBs is regarded as a challenge for practical applications. Herein, a workable lithium metal anode with an artificial hybrid layer composed of polymer and alloy is designed and prepared by a simple chemical modification strategy. Tr...

Nanobody Conjugated Nanotubes for Targeted Near-Infrared in vivo Imaging and Sensing.

Fluorescent nanomaterials such as single-walled carbon nanotubes (SWCNTs) have many advantages in terms of their photophysics, but it is difficult to target them to specific locations in living systems. In contrast, the green fluorescent protein (GFP) has been genetically fused to proteins in many cells and organisms. Therefore, GFP can be seen not only as a fluorophore but as a universal target/handle. Here, we report the conjugation of GFP- binding nanobodies to DNA wrapped SWCNTs. This approach combines ...

Direct Monitoring Cell Membrane Vesiculation with 2D AuNP@MnO2Nanosheet Supraparticles at Single-Particle Level.

We herein demonstrate robust two-dimensional (2D) UFO-shaped plasmonic supraparticles made of gold nanoparticles (AuNPs) and MnO2 nanosheets (denoted as AMNS-SPs) for directly monitoring cell membrane vesiculation at single-particle level. Because the decorated MnO2 nanosheets are ultrathin (4.2 nm) and have large diameter (230 nm), they are flexible enough for deformation and fold for parceling the AuNPs during the endocytosis process. Correspondingly, the surrounding refractive index of the AuNPs increase...

Mechanical activation drastically accelerates amide bond hydrolysis, matching enzyme activity.

Amide bonds, which include peptide bonds connecting amino acids in proteins and polypeptides, give proteins and synthetic polyamides their enormous strength. Although proteins and polyamides sustain mechanical force in nature and technology, how force affects amide and peptide bond stability is still unknown. Using single molecule force spectroscopy, we discover that forces of only a few hundred pN accelerate amide hydrolysis 10^9-fold, an acceleration hitherto only known from proteolytic enzymes. The drast...

Efficient Separation of Cis- and Trans-1,2-dichloroethene Isomers by Adaptive Biphen3arene Crystals.

Herein, we report the highly efficient separation of industrially important cis- and trans-1,2-dichloroethene (cis-DCE and trans-DCE) isomers by activated crystalline 2,2',4,4'-tetramethoxyl biphen[3]arene (MeBP3) materials, MeBP3α. MeBP3 can be synthesized in excellent yield (99%); cyclic pentamer is also yielded when using 1,2-dichloroethane as solvent. The structure of MeBP3 in CH3CN@MeBP3 crystal displays triangle-shape topology, forming 1D channels through window-to-window packing. Desolvated crystall...

a-Arylation of Carbonyl Compounds by Oxidative C-C Bond Activation.

A synthetically useful approach for the direct α-arylation of carbonyl compounds via a novel oxidative C-C bond activation is reported. This mechanistically unusual process relies on a 1,2-aryl shift and results in all-carbon quaternary centers. The transformation displays broad functional group tolerance and is amenable to an asymmetric variant.

CO2 Fixation and Catalytic Reduction by a Neutral Aluminium Double bond.

CO2 fixation and reduction to value added products is of utmost importance in the battle against rising CO2 levels in the Earth's atmosphere. Herein we present the use of an organoaluminium complex containing a formal aluminium double bond (dialumene), and thus an alkene equivalent, for the fixation and reduction of CO2. The CO2 fixation complex undergoes further reactivity in either the absence or presence of additional CO2, resulting in the first dialuminium carbonyl and carbonate complexes, respectively....

A General and Air-tolerant Strategy to Conjugated Polymers within Seconds under Pd(I) Dimer Catalysis.

While current M(0)/M(II) based polymerization strategies largely focus on fine-tuning the catalyst, reagents and conditions for each and every monomer, this report discloses a single method that allows access to a variety of different conjugated polymers within seconds at room temperature. Key to this privileged reactivity is an air- and moisture stable dinuclear Pd(I) catalyst. The method is operationally simple, robust and tolerant to oxygen.

An industry in transition: The chemical industry and the megatrends driving its forthcoming transformation.

Significant product and process innovation is taking place in the chemical industry. Rather than willing to make bold predictions, this study emphasizes that said change due to impact both main segments of the industry is driven by societal megatrends concerning the environment, health, and energy which permeate societies on a global scale.

Ultrathin Metal-Organic Framework Nanosheets with Ultrahigh Loading of Single Pt Atoms for Efficient Visible-Light-Driven Photocatalytic H₂ Evolution.

It is desirable yet challenging to synthesize stable single-atom catalysts (SACs) with a high loading of metal atoms. The conventional methods involve anchoring of single atoms onto suitable scaffolds through a post-modification process, but the loading of single metal atoms is generally less than 2 weight % (wt %). Here, we report a surfactant-stabilized coordination strategy towards two-dimensional (2D) SACs with an ultrahigh Pt loading of 12.0 wt %, by assembly of pre-formed single Pt atom coordinated po...

Protecting Group-Controlled Enzymatic Glycosylation of Oligo-N-Acetyllactosamine Derivatives.

We describe a chemoenzymatic strategy that can give a library of differentially fucosylated and sialylated oligosaccharides starting from a single chemically synthesized tri-N-acetyllactosamine derivative. The common precursor could easily be converted into 6 different hexasaccharides in which the glucosamine moieties are either acetylated (GlcNAc) or modified as a free amine (GlcNH2) or Boc (GlcNHBoc). Fucosylation of the resulting compounds by a recombinant fucosyl transferase resulted in only modificatio...

Hydrogen by Deuterium Substitution in an Aldehyde Tunes the Regioselectivity by a Nonheme Manganese(III)-Peroxo Complex.

Mononuclear nonheme Mn(III)-peroxo complexes are important intermediates in biology, and for instance take part in the oxygen activation by Photosystem II. Herein, we present work on two novel isomeric biomimetic side-on Mn(III)-peroxo intermediates with bispidine ligand system and reactivity patterns with aldehydes. The complexes are characterized with UV-Visible and mass spectrometric techniques and reaction rates with cyclohexane carboxaldehyde (CCA) have been measured. The reaction gives an unusual regi...

Tetralithio Metalla-aromatics with Two Independent Perpendicular Dilithio Aromatic Rings Spiro-fused by One Manganese Atom.

Herein, we present the realization of a class of unprecedented aromatic structures 2: metalla-aromatics with two independent and perpendicular aromatic rings spiro-fused by a transition-metal spiro atom, of which their corresponding organic analogues are impossible. Tetralithio spiro manganacycles 2 are readily synthesized from 1,4-dilithio-1,3-butadienes 1 and MnCl2 in the presence of lithium. The aromaticity of 2 is supported by experimental measurements (X-ray structural analysis, NMR) and theoretical an...

C-H and C-F Bond Activation Reactions of Fluorinated Propenes at Rhodium: Distinctive Reactivity of the Refrigerant HFO-1234yf.

The reaction of [Rh(H)(PEt3)3] (1) with the refrigerant HFO-1234yf (2,3,3,3-tetrafluoropropene) affords an efficient route to obtain [Rh(F)(PEt3)3] (3) by C-F bond activation. Catalytic hydrodefluorinations were achieved in the presence of the silane HSiPh3. In the presence of fluorosilane the fluorido complex 3 provides a C-H bond activation followed by a 1,2-fluorine shift to produce [Rh{(E)-C(CF3)=CHF}(PEt3)3] (4). Similar rearrangements of HFO-1234yf were observed at [Rh(E)(PEt3)3] (E = Bpin (6), C7D7 (...

Biocatalytic strategy for highly diastereo- and enantioselective synthesis of 2,3-dihydrobenzofuran based tricyclic scaffolds.

2,3-Dihydrobenzofurans are key pharmacophores in many synthetic and naturally occurring bioactive molecules. A biocatalytic strategy is reported here for the highly diastereo- and enantioselective construction of stereochemically dense 2,3-dihydrobenzofurans in excellent enantiopurity (>99.9% de and ee), high yields, and on a preparative scale via benzofuran cyclopropanation with engineered myoglobins. Computational and structure-reactivity studies provide insights into the mechanism of this unprecedented i...

Silica-Supported Molybdenum-Oxo alkylidenes: Bridging the Gap between Internal and Terminal Olefin Metathesis.

Grafting a Mo oxo alkylidene on silica (partially dehydroxylated at 700 °C) affords the first example of a well-defined silica-supported molybdenum oxo alkylidene, an analogue of the putative active sites in heterogeneous Mo-based metathesis catalysts. In contrast to its W analogue that shows poor activity towards terminal olefin due to the formation of stable off-cycle metallacyclobutane intermediate, this Mo catalyst shows high metathesis activity for both terminal and internal olefins, that is consisten...

Targeted Enzyme Activated Two-Photon Fluorescent Probes: A Case Study of CYP3A4 Using a Two-Dimensional Design Strategy.

Nowadays, the rapid development of fluorescent probe for monitoring target enzyme is still a great challenge, due to the lack of efficient way to optimize a specific fluorophore. Herein, a practical two-dimension molecular strategy was designed to construct an isoform-specific probe for CYP3A4, a key cytochrome P450 isoform responsible for oxidize most of clinical drugs. In first dimension of the molecular design, using ensemble-based virtual screening, the potential two-photon fluorophore substrate (NN) fo...


Advertisement
Quick Search
Advertisement
Advertisement