"Зелений" синтез етилових естерів 4-гідрокси-2-оксо-1,2-дигідрохінолін-3-карбонових кислот

One of the most convenient methods for obtaining ethyl of N-substituted 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylates and their tricyclic analogues at present is condensation of the corresponding anilines with triethyl methanetricarboxylate. In spite of the fact that there are many methods describing the successful performance of this reaction in conditions of laboratory, but unfortunately, all of them appeared to be completely unusable for large production for a variety of reasons. The study of quality of the esters of 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acids by HPLC has shown that all of them contain from 2.4 to 5.6% of specific admixtures of 4-hydroxy-1,2-dihydroquinolin- 2-ones. In laboratory conditions these amounts can be neglected, but for industrial manufacture they can turn into great losses. The source of admixtures of 4-hydroxy-1,2-dihydroquinolin-2-ones appearing in crude esters can be only the esters themselves. It is obvious that ester grouping is partially destroyed not in the process of separation of the final products, but during the course of the basic reaction. It has been experimentally proven that the cause of contamination of the target products with the admixtures of the corresponding 4-hydroxy-1,2-dihydroquinolin-2-ones is water, which is present in reagents. Applying the principles of «green chemistry» the alternative for carrying out the syntheses of ethyl 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylates adapted for industrial manufacture has been suggested on the basis of N-substituted anilines and triethyl methanetricarboxylate.Одним из наиболее удобных способов получения этиловых эфиров N-замещённых 4-гидрокси-2-оксо-1,2-дигидрохинолин-3-карбоновых кислот и их трициклических аналогов в настоящее время остаётся конденсация соответствующих анилинов с триэтилметантрикарбоксилатом. Несмотря на то, что методов успешного проведения этой реакции в лабораторных условиях описано достаточно много, все они, к сожалению, по разным причинам оказались совершенно непригодными для крупного производства. Изучение качества получаемых сложных эфиров 4-гидрокси-2-оксо-1,2-дигидрохинолин-3-карбоновых кислот методом ВЭЖХ показало, что все они содержат от 2,4 до 5,6% специфических примесей 4-гидрокси-1,2-дигидрохинолин-2-онов. В лабораторной практике этими количествами можно пренебречь, но для промышленного производства они могут обернуться значительными потерями. Источником появления в неочищенных эфирах примесей 4-гидрокси-1,2-дигидрохинолин-2-онов могут быть только сами эти эфиры. Очевидно сложноэфирная группировка частично разрушается не при выделении конечных продуктов, а ещё в процессе проведения основной реакции. Экспериментально доказано, что причиной загрязнения целевых продуктов примесями соответствующих 4-гидрокси-1,2-дигидрохинолин-2-онов является присутствующая в реагентах вода. Руководствуясь принципами «зелёной химии», мы предложили адаптированный под промышленное производство вариант проведения синтезов этиловых эфиров 4-гидрокси-2-оксо-1,2-дигидрохинолин-3-карбоновых кислот на основе N-замещённых анилинов и триэтилметантрикарбоксилата.Одним з найбільш зручних способів одержання етилових естерів N-заміщених 4-гідрокси-2-оксо-1,2-дигідрохінолін-3-карбонових кислот та їх трициклічних аналогів на теперішній час залишається конденсація відповідних анілінів з триетилметантрикарбоксилатом. Незважаючи на те, що методів успішного проведення цієї реакції в лабораторних умовах описано досить багато, всі вони, на жаль, з різних причин виявились зовсім непридатними для масштабного виробництва. Вивчення якості одержуваних естерів 4-гідрокси-2- оксо-1,2-дигідрохінолін-3-карбонових кислот методом ВЕРХ показало, що всі вони містять від 2,4 до 5,6% специфічних домішок 4-гідрокси-1,2-дигідрохінолін-2-онів. У лабораторній практиці такими кількостями можна знехтувати, але для промислового виробництва вони можуть обернутися значними втратами. Джерелом появи в неочищених естерах домішок 4-гідрокси-1,2-дигідрохінолін-2-онів можуть бути тільки самі ці естери. Очевидно естерне угрупування частково розкладається не при виділенні кінцевих продуктів, а ще в процесі проведення основної реакції. Експериментально доведено, що причиною забруднення цільових продуктів специфічними домішками відповідних 4-гідрокси-1,2-дигідрохінолін-2-онів є присутня в реагентах вода. Керуючись принципами «зеленої хімії», ми запропонували адаптований під промислове виробництво варіант проведення синтезів етилових естерів 4-гідрокси-2-оксо-1,2-дигідрохінолін-3-карбонових кислот на основі N-заміщених анілінів та триетилметантрикарбоксилату

Clustering in light nuclei in fragmentation above 1 A GeV

The relativistic invariant approach is applied to analyzing the 3.3 A GeV $^{22}$Ne fragmentation in a nuclear track emulsion. New results on few-body dissociations have been obtained from the emulsion exposures to 2.1 A GeV $^{14}$N and 1.2 A GeV $^{9}$Be nuclei. It can be asserted that the use of the invariant approach is an effective means of obtaining conclusions about the behavior of systems involving a few He nuclei at a relative energy close to 1 MeV per nucleon. The first observations of fragmentation of 1.2 A GeV $^{8}$B and $^{9}$C nuclei in emulsion are described. The presented results allow one to justify the development of few-body aspects of nuclear astrophysics.Comment: 7 pages, 8 figures, 3 tables, Nuclear Physics in Astrophysics-2, 16-20 May, 2005 (ATOMKI), Debrecen, Hungar

Fast bistable intensive light scattering in helix-free ferroelectric liquid crystals.

A new type of ferroelectric liquid crystal (FLC) is considered, where the reorientation of the director (main optical axes) at the interaction of an electric field with the FLC's spontaneous polarization is due to the movement of spatially localized waves with a stationary profile: solitons arise at the transition due to the Maxwellian mechanism of energy dissipation. Under certain conditions, the appearance of such waves leads to the formation of a structure of transient domains, and as a consequence, to the scattering of light. The Maxwellian mechanism of energy dissipation allows one to reduce the electric field strength at which the maximum efficiency of light scattering is achieved down to 2-3 V/μm and to increase the frequency of light modulation up to 3-5 kHz. Intensive bistable light scattering in an electro-optical cell filled with a specially designed helix-free FLC was studied, and a stable scattering state can be switched on and off for a few tens of microseconds and memorized for a few tens of seconds.Russian Academy of SciencesThis is the author accepted manuscript. The final version is available from The Optical Society via http://dx.doi.org/10.1364/AO.55.00348

Double-spiral magnetic structure of the Fe/Cr multilayer revealed by nuclear resonance scattering

We have studied the magnetization depth profiles in a [57Fe(dFe)/Cr(dCr)]x30 multilayer with ultrathin Fe layers and nominal thickness of the chromium spacers dCr 2.0 nm using nuclear resonance scattering of synchrotron radiation. The presence of a broad pure-magnetic half-order (1/2) Bragg reflection has been detected at zero external field. The joint fit of the reflectivity curves and Mossbauer spectra of reflectivity measured near the critical angle and at the "magnetic" peak reveals that the magnetic structure of the multilayer is formed by two spirals, one in the odd and another one in the even iron layers, with the opposite signs of rotation. The double-spiral structure starts from the surface with the almost antiferromagnetic alignment of the adjacent Fe layers. The rotation of the two spirals leads to nearly ferromagnetic alignment of the two magnetic subsystems at some depth, where the sudden turn of the magnetic vectors by ~180 deg (spin-flop) appears, and both spirals start to rotate in opposite directions. The observation of this unusual double-spiral magnetic structure suggests that the unique properties of giant magneto-resistance devices can be further tailored using ultrathin magnetic layers.Comment: 9 pages, 3 figure

Topology of "white" stars in relativistic fragmentation of light nuclei

In the present paper, experimental observations of the multifragmentation processes of light relativistic nuclei carried out by means of emulsions are reviewed. Events of the type of "white" stars in which the dissociation of relativistic nuclei is not accompanied by the production of mesons and the target-nucleus fragments are considered. A distinctive feature of the charge topology in the dissociation of the Ne, Mg, Si, and S nuclei is an almost total suppression of the binary splitting of nuclei to fragments with charges higher than 2. The growth of the nuclear fragmentation degree is revealed in an increase in the multiplicity of singly and doubly charged fragments with decreasing charge of the non-excited part of the fragmenting nucleus. The processes of dissociation of stable Li, Be, B, C, N, and O isotopes to charged fragments were used to study special features of the formation of systems consisting of the lightest $\alpha$, d, and t nuclei. Clustering in form of the $^3$He nucleus can be detected in "white" stars via the dissociation of neutron-deficient Be, B, C, and N isotopes.Comment: 20 pages, 3 figures, 9 tables, conference: Conference on Physics of Fundamental Interactions, Moscow, Russia, 1-5 Mar 2004.(Author's translation

Representative elementary volume via averaged scalar Minkowski functionals

Representative Elementary Volume (REV) at which the material properties do not vary with change in volume is an important quantity for making measurements or simulations which represent the whole. We discuss the geometrical method to evaluation of REV based on the quantities coming in the Steiner formula from convex geometry. For bodies in the three-space this formula gives us four scalar functionals known as scalar Minkowski functionals. We demonstrate on certain samples that the values of such averaged functionals almost stabilize for cells for which the length of edges are greater than certain threshold value R. Therefore, from this point of view, it is reasonable to consider cubes of volume R^3 as representative elementary volumes.Comment: 7 page

Fragmentation of relativistic nuclei in peripheral interactions in nuclear track emulsion

The technique of nuclear track emulsions is used to explore the fragmentation of light relativistic nuclei down to the most peripheral interactions - nuclear "white" stars. A complete pattern of therelativistic dissociation of a $^8$B nucleus with target fragment accompaniment is presented. Relativistic dissociation $^{9}$Be$\to2\alpha$ is explored using significant statistics and a relative contribution of $^{8}$Be decays from 0$^+$ and 2$^+$ states is established. Target fragment accompaniments are shown for relativistic fragmentation $^{14}$N$\to$3He+H and $^{22}$Ne$\to$5He. The leading role of the electromagnetic dissociation on heavy nuclei with respect to break-ups on target protons is demonstrated in all these cases. It is possible to conclude that the peripheral dissociation of relativistic nuclei in nuclear track emulsion is a unique tool to study many-body systems composed of lightest nuclei and nucleons in the energy scale relevant for nuclear astrophysics.Comment: 15 pages, 4 figures, 4 tables, conference: Relativistic nuclear physics: from Nuclotron to LHC energies, Kiev, June 18-22, 200

Search for a signal on intermediate baryon systems formation in hadron-nuclear and nuclear-nuclear interactions at high energies

We have analyzed the behavior of different characteristics of hadron-nuclear and nuclear-nuclear interactions as a function of centrality to get a signal on the formation of intermediate baryon systems. We observed that the data demonstrate the regime change and saturation. The angular distributions of slow particles exhibit some structure in the above mentioned reactions at low energy. We believe that the structure could be connected with the formation and decay of the percolation cluster. With increasing the mass of colliding nuclei, the structure starts to become weak and almost disappears ultimately. This shows that the number of secondary internuclear interactions increases with increasing the mass of the colliding nuclei. The latter could be a reason of the disintegration of any intermediate formations as well as clusters, which decrease their influence on the angular distribution of the emitted particles.Comment: 2 pages and one figur

Project approach to the development of rural tourism

The authors of the article provide an overview of scientific approaches to the definition of the essence and role of event and gastronomic tourism against the backdrop of the rural tourism promotion currently carried out. The interrelation between all the aforementioned types of tourism and the expediency of their joint development are substantiated. The necessity of holding events in order to smooth out the seasonality of rural tourism and attract tourists interested not only in standard services of rural guest houses but also in entertainment events is proved. Special emphasis is placed on the application of the project approach to the process of creating events. A description of the festivals held in the Vologda region is provided. The main problems of the implementation of project management at the municipal level are identified. The possibility of holding gastronomic festivals within the clusters operating in the region is considered. The example of the «SyrFest» gastronomic festival is used to demonstrate a possible project structure designed for such event

Electromagnetic dissociation of relativistic 8^8B nuclei in nuclear track emulsion

Experimental data on fragmentation channels in peripheral interactions of $^8$B nuclei in nuclear track emulsions are presented. A detailed analysis made it possible to justify selections of events of the electromagnetic-dissociation process $^8$B $\to^7$Be + \emph{p} and to estimate its cross section. Events of $^{10}$C peripheral dissociation that were observed in the same exposure are described.Comment: 12 pages, 10 figures, 4 tables, Published in Phys.Atom.Nucl.72:690-701,200