Reductive cleavage of disulfide bonds is an important step in many biological and chemical processes. Whether occurs stepwise or concertedly with electron transfer interest. Also interest whether the bond reduced directly by intermolecular from external reducing agent mediated intramolecularly internal another redox-active moiety elsewhere within molecule. The electrochemical reductions 4,4'-bipyridyl-3,3'-disulfide (1) di-N-methylated derivative (2(2+)) have been studied acetonitrile....

To investigate neighboring amide participation in thioether oxidation, which may be relevant to brain oxidative stress accompanying beta-amyloid peptide aggregation, conformationally constrained methylthionorbornyl derivatives with amido moieties were synthesized and characterized, including an X-ray crystallographic study of one them. Electrochemical oxidation these compounds, studied by cyclic voltammetry, revealed that their peak potentials less positive for those compounds group was...

Tungsten(VI) oxide (WO3) powders of monoclinic crystal structure with high crystallinity have been synthesized by hydrothermal treatment (HTT), at 523 or 573 K, aqueous tungstic acid (H2WO4) solutions prepared from sodium tungstate ion-exchange (IE) a proton-type resin. HTT and/or calcination home-made and commercial H2WO4 solids tungstite also produced WO3. These WO3 various physical properties were used as photocatalysts for evolution oxygen (O2) an silver sulfate solution, the correlation...

Fatty acids (FAs) are the central components of life: they constitute biological membranes in form lipid, act as signaling molecules, and used energy sources. FAs classified according to their chain lengths number position carbon-carbon double bond, physiological character is largely defined by these structural properties. Determination precise properties crucial for characterizing FAs, but pinpointing exact bond FA molecules challenging. Herein, a new analytical method reported determining...

Methionine residues have been shown to function as efficient "hopping" sites in long-range electron transfer model polyprolyl peptides. We suggest that a key this ability of methionine is stabilization the transient sulfur radical cation by neighboring proline amide participation. That is, system pyrrolidine lowers oxidation potential thioether over 0.5 V formation two-center three-electron SO bond.

Pseudohyperkalemia is defined as a serum potassium concentration 0.4 mEq/l greater than the plasma concentration. The basis of this phenomenon release intracellular from platelets, leukocytes, or erythrocytes, commonly in setting extreme leukocytosis (> 10 x 10(4)/microl) thrombocytosis 60 10(4)/microl). We report case pseudohyperkalemia patient with chronic renal failure and polycythemia vera without finding severe (white blood cell count 1.88 10(4)/microl platelet 37.9 10(4)/microl,...

Electronic absorption spectra and quantum chemical calculations of the radical cations m-terphenyl tert-butyl thioethers, where S-t-Bu bond is forced to be perpendicular central phenyl ring, show occurrence through-space [π···S···π](+) bonding interactions which lead a stabilization thioether cations. In corresponding methyl derivatives there competition between delocalization hole that centered on p-AO S atom into π-system ring or through space flanking groups, leads mixture planar...

It is important to evaluate the amount of daptomycin (DAP) distributed skeletal muscles elucidate mechanisms related penetration and side effects, such as myopathies. However, no attempt has been made measure DAP concentrations in muscles. The study's aim investigate feasibility trypsin digestion, a muscle sample preparation technique for determination murine muscle, was evaluated conjunction with conventional HPLC-UV analysis. Compared less recovered from spiked by extraction, including...

The electrochemical oxidation of thioethers is shown to be facilitated by neighboring amide participation. 1H NMR spectroscopic analysis in acetonitrile solution two conformationally constrained compounds with such facilitation shows that two-electron participation the π2 orbital can occur stabilize developing sulfur radical cation.

A highly sensitive high-performance liquid chromatography method has been developed using the pre-column fluorescent derivatization of daptomycin (DAP) through cyclization amino group ornithine with 2,3-naphthalenedialdehyde. With proposed method, limits detection and quantification DAP in murine serum were 8 3 nmol/L, respectively, calibration curve was linear across examined dynamic range from nmol/L to 1 μmol/L (n = 8, r 0.9986). This is suitable for animal experiments examining side...

The substrate selectivities of three endonucleases were studied quantitatively using capillary zone electrophoresis to find one giving N2-ethyl(Et)-2′-deoxyguanosine-5′-monophosphate (5′-dGMP) and cyclic 1,N2-propano(CPr)-5′-dGMP from DNAs damaged by acetaldehyde (AA). Six 2′-deoxyribonucleoside-5′-monophosphates be quantified in the hydrolysis solutions DNAs, namely, Et-5′-dGMP, CPr-5′-dGMP, four authentic ones, completely separated a 100 mM borate running buffer solution having an...

Electroorganic synthesis (EOS) enables unattainable molecular transformations that cannot be achieved through conventional acid/base or thermal reactions to realized by exploiting redox capabilities. The use of acetals as...

Cyclic-1,N2-propano-2'-deoxyguanosine-d7 (CPr-dG-d7) was prepared as an isotopic internal standard (IS) for electrospray ionization tandem mass spectrometry (ESI-MS/MS) quantification of CPr-dG in DNA a candidate cancer risk marker acetaldehyde intake, mainly from drinking. The deuterated compound reasonably synthesized acetaldehyde-d4 and 2'-deoxyguanosine deuterium oxide (D2O), preventing the atoms being substituted by hydrogen atoms, which occurred seriously aqueous synthesis media via...

The deuteration of N2-ethyl-2′-deoxyguanosine (Et-dG), which is a DNA adduct generated from acetaldehyde, was studied by the addition reaction acetaldehyde-d4 to 2′-deoxyguanosine (dG) in deuterium oxide (D2O), with aim obtain an isotope internal standard for liquid chromatography/tandem mass spectrometry (LC/MS/MS) quantitation Et-dG. replacement dG C-8 hydrogen atom deuteron took place at 50°C D2O and afforded mixture Et-dG-d4 Et-dG-d5. Et-dG-d4, stable aqueous solutions, prepared...

Variable temperature 1 H NMR spectroscopic studies of 2, 6‐di( o ‐anisyl) anisole show syn and anti atropisomers at low temperature. The barrier for interconverting these isomers by rotation about the aryl‐aryl bond, found fitting experimental data, is 41.2 kJ/mol. Copyright © 2012 John Wiley & Sons, Ltd.

Disulfide bonds of 2-isocyanatophenyl methyl disulfide and 2-endo-isocyanato-6-endo-(methyldisulfanyl)bicyclo[2.2.1]heptane showed neighboring group participation in the formation thiocarbamates. Natural Bond Orbital (NBO) analyses revealed that unusual nucleophilicity requires a rigid through-space interaction between lone pair bond an antibonding orbital isocyanate.

Daptomycin is active against Staphylococcus aureus including methicillin-resistant S. (MRSA), demonstrating efficacy in the treatment of infections diabetic patients. However, daptomycin degrades 5% glucose solution, and data on hyperglycemic patients are limited. Therefore, we investigated effect high levels blood concentration daptomycin. The simulated human exposure to was compared a neutropenic murine thigh model, with without hyperglycemia. A clinically isolated MRSA strain ATCC25923...

Quantification of four extracellular matrices commonly found in foods with functional claims was conducted using capillary zone electrophoresis direct ultraviolet (UV) absorbance detection at 200 nm. The polymeric compounds, namely, proteoglycan, chondroitin sulfate, hyaluronic acid, and collagen, were separated 100 mM borate buffer (pH 10.0) capillaries coated poly-N,N-dimethylacrylamide on the inner wall, which almost completely suppressed electroosmotic flow to give reproducible migration...