Diels-Alder reaction between naphthalene and N-phenylmaleimide under mild conditions

The rate and equilibrium constants for the Diels-Alder reactions between benzene or naphthalene and several dienophiles at 25°C were calculated from the data on the ionization potentials of dienes and electron affinity energies of dienophiles, as well as the reaction enthalpies. The highest yield of the adduct was predicted for the reaction of naphthalene with N-phenylmaleimide. However, the time of its formation in 50% yield exceeds 30 years. The use of gallium chloride as a catalyst affords the endo-adduct for seven days at room temperature in 30% yield. The rate ((2±0.5)·10-6 L mol-1 s-1) and equilibrium constants (5±2 L mol-1) of the reaction were determined

Decentralized control of a group of quadrocopters using the molecular dynamics method

The development of artificial intelligence systems based on various principles, including anthropomorphic and nature-like systems, as well as progress in the construction of quadrocopters for various purposes, made relevant the practical application of these tools for the effective monitoring of underlying surfaces by groups of such devices. The solution of this problem is associated with the effective control of them in conditions of passive and active interference that impedes the fulfillment of missions, as well as with the problem of reconfiguring their construction in case of fail. The model obtained in the work and the calculations made it possible to conclude that the use of the following approach in the future will allow the creation of a self-government system by an independent group of quadrocopters, capable of performing various missions without control from the Earth under conditions of active and passive interference, as well as with permanent failure of quadrocopters

Activation and reaction volumes of the reactions of o-and p-nitrophenylsulfenyl chlorides with styrene and cyclohexene in some solvents

The effect of hydrostatic pressure below 1000 kg cm-2 on the rate of reactions of o-and p-nitrophenylsulfenyl chlorides with styrene and cyclohexene was studied. The activation and reaction volumes (cm3 mol-1) for the reactions of o-nitrophenylsulfenyl chloride with styrene in acetonitrile (-23.1 and -23.6), 1,2-dichloroethane (-29.2 and -24.7), chlorobenzene (no, -20.2), and anisole (-25.1 and -21.2) and for the reaction of p-nitrophenylsulfenyl chloride with styrene in carbon tetrachloride (-39.5±1.5 and -22.0) were determined. In carbon tetrachloride the activation volumes for the reactions of cyclohexene with o-and p-nitrophenylsulfenyl chlorides (-37.7±2.0 and -40.9±1.2 cm 3 mol-1, respectively) are almost the same and coincide with the data for the reactions with styrene. The considerable decrease in the volume of the transition state in the nonpolar solvent is considered as a consequence of the enhanced electrostriction of carbon tetrachloride in the solvate sphere of the transition state of the reaction, which excludes the nonpolar transition state of the sulfuran type. © 2007 Springer Science+Business Media, Inc

Helicobacter pylori roles in haematology disease pathogenesis

Helicobacter pylori is considered to be one of the significant reasons of formation of gastroduodenal pathology. Data on the role of H. pylori in the development of extragastric diseases are confirmed by a positive effect of eradication on peripheral blood changes. In spite of this fact both aspects are still not revealed. However, undoubtedly that H. pylori persistence on gastric epithelium creates conditions for chronic local and systematic inflammation. The aim of the sur- vey was the analysis of literary data about bacterial factors in the development of iron-, vitamin B12-deficiency anaemia and thrombocytopenic purpura included by the international consensus into the circle of evedences for diagnosis and treatment of H. pylori. Material and methods. There was accomplished search of literature sources with the help of data bases PubMed, CyberLeninka, eLibrary, Google Scholar. The results of our analysis specify mechanisms of cer- tain blood diseases pathogenesis in association with H. pylori. Multiple roles of virulent strains of pathogen in anaemia and thrombocytopenic purpura include: development of erosive and ulcerative lesions of mucosa, hypoacidity, chron- ic inflammation and autoimmune response. Data about these changes in haematological syndromes and independent eradication effects on blood parameters normalisation, are controversial. Н. pylori host iron competition theory has not been found convincing confirmation. Conclusions. It is necessary to study more deeply the connection of H. pylori and haematological diseases. The dietary research and application to maintain the mucous integrity and bacterial adhesion prevention are perspective

Micelles and aggregates of oxyethylated isononylphenols and their extraction properties near cloud point

We used nuclear magnetic resonance (NMR) spectroscopy and dynamic light scattering (DLS) techniques to study the structural and dynamic properties of micellar solutions of nonionic surfactants of a homologous series of oxyethylated isononylphenols - C9H19C6H 4O(C2H4O)nH, where n = 6, 8, 9, 10, or 12 - in a wide range of temperatures, including cloud points. The radii of the micelles and aggregates, as well as their compositions at different concentrations of surfactant, were determined. Using aqueous phenol solutions as a model, we studied the process of cloud point extraction with oxyethylated isononylphenols. © 2014 American Chemical Society

Effect of pressure on the rate of the Diels-Alder reaction of diethyl azodicarboxylate with 9,10-dimethylanthracene

The enthalpy, entropy, and volume of activation and volume of the Diels-Alder reaction of diethyl azodicarboxylate with 9,10-dimethylanthracene in 1,2-dichloroethane have been determined. Possible factors responsible for the sharp difference between the volumes of activation and reaction are considered. © 2014 Pleiades Publishing, Ltd