New approaches to the synthesis of functionally substituted pyrido[3′,2′:4,5]thieno[3,2-b]pyridines and the structure of the products obtained

Substituted pyrido,[3',2':4,5]thieno[3,2-b]pyndines were obtained by the reaction of 3-amino-2-benzoylthieno [2,3-b]pyridines with malononitrile and the reaction of 3-cyanopyridine-2(IH)-thiones with 2-aryl-3-bromo-I,I-dicyanopropene. 2-Amino-4-(4-bromophenyl)-7, 9-dimethyl-3-cyanopyrido [3',2':4,5]thieno[3, 2-b]-pyridine was used for the synthesis of a derivative of pyrido[3",2":4', 5']thieno[2',3':5,6]pyrido[2,3-d]-pyrimidine. The structure of these compounds was confirmed by spectral data and x-ray diffraction structural analysis.Deceased.     

Transient phenomena in o-xylene oxidation in a fluidized bed reactor

The effect of stirring a vanadium-titanium-tellurium catalyst on the yield of the selective oxidation products for oxidation of o-xylene in fluidized bed reactors has been studied. It is shown that the stirring of catalyst pellets increases the yield of phthalic anhydride.

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On the Role Played by Dimers of Radical Cations in the Process of Electrochemical Oxidation–Reduction of Polyaniline: The Data that Were Obtained Using the Method of Cyclic Voltabsorptometry in the Presence of Counteranions of a Diverse Nature

The electrochemical oxidation–reduction of films of polyaniline is studied in the presence of various counteranions. The differential cyclic voltabsorptometric (DCVA) curves (dA/dt relative to potential, where A is the optical absorption) are recorded at characteristic wavelengths corresponding to individual spectrum components previously isolated with the Alentsev–Fok method. The DCVA curves for aqueous solutions of HCl, HClO₄, and H₂SO₄ at different potential scan rates are compared to traditional cyclic voltammograms. For the DCVA curves obtained at 665 nm discovered is one broad peak of dA/dt in the region of potentials between the first and second stages of polyaniline oxidation (0.6 V vs. Ag/AgCl). An assumption is made about a chemical nature of the process of generation of absorption in this spectral region, which, more likely than not, is connected with the emergence of dimers of radical cations of polyaniline. It is discovered that the electrochemical processes in the region of potentials that correspond to the first stage of oxidation give rise to variations in the absorption inside several regions of spectrum: 435 nm (radical cations) and 755 nm (localized polarons). An assumption is made that the first peak of the current corresponds to several successive processes that occur in a polyaniline molecule in the course of oxidation as well as to the existence of heterogeneous regions where the generation of localized polarons proceeds at different rates.     

Methods and equipment of industrial activation analysis

Expanding application of activation analysis in industry resulted in exposure of features related to higher requirements to productivity, reliability, automation level, metrological support of analytical methods and equipment. Based on the application of neutron generators, radioisotope neutron sources, nuclear reactors, electron accelerators as activating radiation sources, high-productivity activation analytical systems used directly in analytical laboratories and plants were constructed. Level of development of the above works makes it possible to conclude that industrial activation analysis has formed as an independent trend of nuclear analytics and has considerable prospects.     

Potential function of internal rotation of (CH3)2CClNO,CH3CCl2NO,and their deuterium analogs

The potential function has been constructed for internal rotation of the NO-group in (CH₃)₂CClNO, CH₃CCl₂NO, and their deuterium analogs. It has been established that the N=O bond in the cis_Cl conformer of CH₃CCl₂NO does not eclipse the C-Cl bond, rather forming an angle of approximately 30. It has been shown that a change in substitutent on the -carbon atom may produce a substantial change in the form of the potential function of internal rotation (PFIR) of the NO group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 550–555, March, 1990.     

Dual reactivity of diphenylphosphinous and phenylphosphonous acid amides in reactions with N-acetoxymethyl-substituted diethylamine,benzamide, and acetamide

Conclusion N-Acetoxymethyldiethylamine reacts with tetraethyldiamidophenylphosphonite and diethylamidodiphenylphosphinite, and N-acetoxymethylbenzamide with tetraethyldiamidophenylphosphonite at the phosphorus atom only to form Arbuzov reaction products. The reaction of N-acetoxymethylacetamide with tetraethyldiamidophenylphosphonite and diethylamidodiphenylphosphinite, and the reaction of N-acetoxymethylbenzamide with diethylamidodiphenylphosphinite proceed at two reaction centers at the phosphorus atom to form the Arbuzov reaction products, and at the nitrogen atom to form acetoxyphosphinites (phosphonites) and N-diethylaminomethylamides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2765–2769, December, 1986.     

Determination of biologically active low-molecular-mass thiols in human blood. III. Highly sensitive narrow-bore isocratic reversed-phase high-performance liquid chromatography with fluorescence detection

The fast isocratic narrow-bore reversed-phase high-performance liquid chromatographic method employing fluorescence detection is described for the precise reproducible simultaneous measurement of total homocysteine, cysteine and glutathione in human blood. Sample preparation involves conversion of disulfides to free thiols with triphenylphosphine, precipitation of proteins with sulfosalicylic acid, and conjugation of thiols with monobromobimane. Optimized sample preparation conditions as well as chromatographic conditions allowed to obtain reliable quantitative results within the concentration range corresponding to the levels of these thiols in human blood in norm and pathology. The detection limit was approximately 70 amol for all labeled aminothiols. The proposed method for these compounds analysis includes simple sample preparation, high selectivity, good linearity (r2>0.998), high reproducibility (within-run precision for derivatized aminothiol peaks area RSD<1.8% for three times consequently injected sample); high reliability and the small sample volume (1 microl) required for analysis make it suitable for clinical studies.     

Role of resonances in building cross sections: Comparison between the Mittag–Leffler and the T‐matrix Green function expansion approaches

Peaks in collision cross sections are often interpreted as resonances. The complex dilation method, as well as other methods relying on analytic continuation of the scattering formalism, can be used to clarify whether these structures are true resonances in the sense that they are poles of the S‐matrix and the associated Green function. The performance of the Mittag–Leffler expansion and T‐matrix Green function expansion methods are formally and computationally compared. The two methods are applied to two model potentials. Eigenenergies, s‐wave residues, and cross sections are computed with both methods. The resonance contributions to the cross sections are further analyzed by removing the residue contributions from the Mittag–Leffler and Green function expansion sums, respectively. It is suggested that the contribution of a resonance to a cross section should be defined through its S‐matrix residue. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Electronic Structure of Substituted Magnesium Malonates and Malonic Aldehyde Dianion Associates

Ab initio calculations using a molecular pseudopotential and an all-electron approximation have been carried out with various basis sets for Mg complexes and for dianions of malonic aldehyde and its imino and chloro derivatives. The valence levels are reproduced most adequately, whereas the atomic charges and bond characteristics depend heavily on the basis used. Employing a pseudopotential does not change the quality of the electronic characteristics of the system, slightly increasing the existing charge separation. The Cl atom in the -position is involved in -conjugation of the dicarbonyl cycle, causing antibonding in the dianion. Introduction of Mg considerably increases the mesomeric effect of Cl and electron density on the N and O atoms, slightly changing the charges on the carbon atoms. According to the calculations, the Mg–O and Mg–N bonds are slightly covalent. The metal AO is not included in the -system of the ring.