Selectivity of 1-O-Propargyl-d-Mannose Preparations

Thanks to their ability to bind to specific biological receptors, mannosylated structures are examined in biomedical applications. One of the most common ways of linking a functional moiety to a structure is to use an azide-alkyne click reaction. Therefore, it is necessary to prepare and isolate a propargylated mannose derivative of high purity to maintain its bioactivity. Three known preparations of propargyl-α-mannopyranoside were revisited, and products were analysed by NMR spectroscopy. The preparations were shown to yield by-products that have not been described in the literature yet. Our experiments showed that one-step procedures could not provide pure propargyl-α-mannopyranoside, while a three-step procedure yielded the desired compound of high purity.     

Iron-Mediated Amination of Hydrocarbons in the Gas Phase

FeNH⁺ is chosen as a model system to probe the transition-metal-mediated transfer of imine groups in the gas phase by mass-spectrometric means. Ab initio calculations at the MR-ACPF level predict FeNH⁺ to have a linear sextet ground state (⁶Σ⁺); a bent quartet state (⁴A′) and a linear doublet state (²Δ) are higher in energy by 0.14 eV and 0.51 eV, respectively. The bond-dissociation energy is determined to D(Fe⁺−NH)=69±2 kcal mol⁻¹ using ion-molecule reactions. Charge-stripping experiments combined with ab initio calculations yield an ionization energy of IE(FeNH⁺)=15.7±0.5 eV. The chemical behavior of FeNH⁺ towards oxygen, water, hydrogen, aliphatic hydrocarbons, benzene, and toluene reveals an intrinsically high reactivity of FeNH⁺. Because a transfer of the 〈NH〉 fragment to the substrate is feasible in most cases, attractive amination reactions like methane→methylamine, benzene→aniline, or toluene→benzylidenamine can be afforded by FeNH⁺.     

The preparation und unusual rearrangement of triply bridged μ-heteromethylenecobalt complexes. Molecular structure of μ-ethoxycarbonylmethylenebis[carbonyl-(η5-cyclopentadienyl)cobalt] (CoCo)

the μ-heteromethylenecobalt complexes, which have been synthesized by photolysis of (η⁵-C₅H₅)Co(CO)₂ in the presence of the corresponding diazoacetates at < ?90°C in tetrahydrofuran, undergo a novel type of intramolecular irreversible rearrangement yielding two isomers. The structure of one of the isomers has been established by X-ray analysis. A comparison of the structural parameters of all known μ-methylene-transition metal complexes shows that the internal angles α of the cyclopropane-like systems are far less sensitive to the compositions and structures of the molecules than the external angles β. The internal angles cannot be readily correlated with other features of the molecule.     

Ermittlung der analysenfrequenz bei diskontinuierlicher prozessanalytischen verfahren: Establishment of the frequency of analysis for discontinuous measurements in process control

Establishment of the frequency of analysis for discontinuous measurements in process control.Application of sampling theory to industrial chemical processes involves special problems arising from the peculiarities of the processes and of the analytical work. Apart from in the process itself, it is necessary to consider the statistical error of the correlation function caused by the finite length of the observed signal. Knowledge of the correlation time of the stochastic signal makes it possible to estimate the optimal time-difference between two analyses, depending on the variance of the process and the allowed analytical tolerance.     

Fast quantification of water in single living cells by near-infrared microscopy

We have set up a near-infrared microscope using a tuneable diode laser in the range from 1530 to 1570 nm. This spectral range is close to the peak of the water overtone absorption. We used this new microscope to study liver cells, hepatocytes, showing that quantitative information of the intracellular water concentration in living cells can be extracted.     

The bioequivalence study of baclofen and lioresal tablets using capillary electrophoresis

A simple and robust analytical method for rapid separation and sensitive quantification of baclofen in human plasma by capillary electrophoresis technique was developed. Electrophoretic separation was optimized and successfully performed using simple sodium tetraborate aqueous solution. Observed detection limit in biological material was 10 ng. Using UV detection at 200 nm excellent linearity (r = 0.999) was observed over the concentration range from 0.025 to 1.0 microg mL(-1). The described method has been validated and applied to the quantitative determination of baclofen in human plasma. The bioavailability of Baclofen (Polpharma) and Lioresal (Novartis) in 18 healthy volunteers was investigated. The results indicate bioequivalence of the reference and Baclofen preparations.     

Soapwort (Saponaria officinalis L.) Extract vs. Synthetic Surfactants—Effect on Skin-Mimetic Models

Our skin is continuously exposed to different amphiphilic substances capable of interaction with its lipids and proteins. We describe the effect of a saponin-rich soapwort extract and of four commonly employed synthetic surfactants: sodium lauryl sulfate (SLS), sodium laureth sulfate (SLES), ammonium lauryl sulfate (ALS), cocamidopropyl betaine (CAPB) on different human skin models. Two human skin cell lines were employed: normal keratinocytes (HaCaT) and human melanoma cells (A375). The liposomes consisting of a dipalmitoylphosphatidylcholine/cholesterol mixture in a molar ratio of 7:3, mimicking the cell membrane of keratinocytes and melanoma cells were employed as the second model. Using dynamic light scattering (DLS), the particle size distribution of liposomes was analyzed before and after contact with the tested (bio)surfactants. The results, supplemented by the protein solubilization tests (albumin denaturation test, zein test) and oil emulsification capacity (using olive oil and engine oil), showed that the soapwort extract affects the skin models to a clearly different extent than any of the tested synthetic surfactants. Its protein and lipid solubilizing potential are much smaller than for the three anionic surfactants (SLS, ALS, SLES). In terms of protein solubilization potential, the soapwort extract is comparable to CAPB, which, however, is much harsher to lipids.     

Superparamagnetic iron oxide/oleic acid nanoparticles with immobilized organosilicon derivatives of N‐(2‐hydroxyethyl)tetrahydroisoquinoline: synthesis,morphology and interaction with normal and tumour cells

Superparamagnetic iron oxide/oleic acid nanoparticles bearing lipid‐like organosilicon N‐(2‐hydroxyethyl)‐1,2,3,4‐tetrahydroisoquinoline derivatives have been synthesized with the aim of their potential biomedical application. X‐ray diffraction analysis, Dynamic light‐scattering measurements, method of magnetogranulometry and some others have been employed to investigate the morphology and properties of the nanoparticles synthesized. The magnetic core diameter of mixed covered nanoparticles ranged between 4.8 and 9.6 nm. The magnetization analyses showed that the particles are superparamagnetic at room temperature. In vitro cell cytotoxicity and intracellular NO generation caused by the water magnetic solution of nanoparticles possessing cytotoxic organosilicon heterocyclic choline analogue, namely N‐(2‐dimethyl‐n‐hexadecylsiloxyethyl)‐N‐methyl‐1,2,3,4‐tetrahydroisoquinolinium iodide, was examined in relation to monolayer human fibrosarcoma (HT‐1080) and mouse hepatoma (MG‐22A) tumour cell lines and normal mouse fibroblasts (NIH 3T3). The biological studies have revealed its selective cytotoxicity in tumour cells and strong effect on MG‐22A cell morphology. Incorporation of the synthesized nanoparticles into cells was observed. Copyright © 2013 John Wiley & Sons, Ltd.