Reactions with Methylamine of Pyrilo-2-cyanines Containing Polyfluorophenyl Substituents

Reactions of symmetric and unsymmetrical pyrilo-2-cyanines containing polyfluorophenyl substituents with methylamine give rise to the corresponding pyridocyanines, 1,3-cyclohexadiene derivatives, or 1-methyl-2-pyridone. The type of the reaction product depends on the structure of the initial dye and the reaction conditions.     

Study of the telomerization of ethylene and 1-hexene by butanal through comparative kinetics

The reaction of ethylene and 1-hexene with butanal was studied using tertiary butyl peroxide initiation at 140°C and a hydrostatic pressure in the range of 250–450 kg/cm². Based on calculated values of the rate constant ratios for the addition reaction of the n-C₃H₇O radical to ethylene (k₀ ^e) and 1-hexene (k₀ ^h), we obtained k₀ ^e/k₀ ^h=3.7 as the rate constant of the decarbonylation reaction of this radical (k_d). The partial chain transfer constants were calculated for the ethylene-butanal system as C_n: C₁=1.0±0.16; C₂=1.0±0.14; C₃=0.9±0.23. The results obtained indicate the nucleophilic character of the n-C₃H₇O radical in these reactions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1356–1360, June, 1990.     

New mesoionic systems of the azolopyridine series. 1. Synthesis and structures of thiazolo[3,2-a]pyridinium 2-thiolates

A procedure was developed for the synthesis of representatives of the previously unknown bicyclic mesoionic thiazolo[3,2-a]pyridinium 2-thiolate system by the reaction of 2-X-N-phenacylpyridinium salts (X = Cl, SMe) with CS₂ in the presence of Et₃N. The three-dimensional structure of 3-(p-nitrobenzoyl)thiazolo[3,2-a]pyridinium 2-thiolate was established by X-ray diffraction analysis.     

Thermodynamics of 15-Crown-5 Complexation with Ag+ and Pb2+ Ions

Heats and constants of 15-crown-5 (R) complexation with silver and lead ions at 298, 308, and 318 K are determined using direct calorimetry. Thermodynamic parameters (G°, H°, S°, and C _p°) of formation of AgR⁺ and PbR²⁺ complexes at various temperatures are calculated. The effects of the properties of the cations and crown ethers on the thermodynamic parameters of complexation are discussed.     

Palladium nitrosoarene complexes in reductive carbonylation of nitroarenes

The reactions of carbon monoxide with the palladium nitrosoarene complexes Pd₂(-OCOR)₂(—CH₂C₆H₄NO)₂ (1, R = Me, CF₃, Bu^t, or Ph) and Pd₂(-OCOR)₂(PhNC₆H₄NO)₂ (2, R = Me, CF₃, Bu^t, or Ph) were studied. Complexes 1 contain the o-nitrosotoluene molecule metallated at the methyl group. In complexes 2, the phenyl-o-nitrosophenylamide ligand coordinated via two nitrogen atoms can be considered as a nitrosobenzene derivative bearing the NPh group in the ortho position of the Ph ring. It all cases, carbonylation of the complexes afforded the corresponding aryl isocyanates Ar—N=C=O or the products of their further transformations. The mechanism of reductive carbonylation of nitroarenes catalyzed by palladium compounds and the role of palladium nitrosoarene complexes as possible intermediates in this process are discussed.     

Synthesis of 2,3,4,5-tetrahydro-1,5-benzox (and thi)azepines and their utilization for the preparation of condensed indoles

A preparative method is proposed for the synthesis of 2,3,4,5-tetrahydro-1,5-benzothiazepine by reductive ring expansion of 4-chromanone and 4-thiochromanone oximes. These compounds were converted to the corresponding N-amino derivatives, which, like arylhydrazines in the Fischer reaction, give new condensed indole systems. The reduction of the oxime (and its tosylate) of 5-oxo-2,3,4,5-tetrahydro-1-benzoxepine was investigated.     

Research on pyranes,their analogs,and related compounds

The action of methanol on methyl 4, 4-dichlorochromene-2-carboxylate (A) gives a 2-substitution product I, readily hydrolyzed in acid solution to a 2-hydroxy derivative C, which undergoes an allylic rearrangement to an ester of chromane-2-carboxylic acid B. Hydrogenation of compound I gives 2-methoxy-2-carbomethoxychromane (II), which is caused to undergo some chemical reactions.For Part XXIII see [4]     

AAS-ETA,ICP-AES and ICP-MS analysis of high purity indium using matrix separation by analytical autoclaves of a special design

The potential of AAS-ETA, ICP-AES and ICP-MS methods in direct mode or with matrix separation are investigated for the analysis of high purity indium. Optimal conditions for the indium separation as difficult soluble oxychloride are established. Analytical autoclaves which allow to perform both digestion and separation procedures simultaneously are used for this purpose. Using the preconcentration method suggested the detection limit of a number of elements was reduced by a factor of 5-100 comparing to the direct determinations.     

Microstructure and superconducting properties of the DyBaCuO ceramic doped with Na<Subscript>2</Subscript>CO<Subscript>3</Subscript>, NaCl,and KClO<Subscript>3</Subscript>

This paper reports on a study of the effect of doping with Na₂CO₃, NaCl, and KClO₃ salts on the microstructure and superconducting characteristics of ceramics with nominal compositions Dy_{1 ? x} M _x Ba₂Cu_{3 ? y} O_{7 ? δ} and DyBa₂Cu_{3 ? y} O_{7 ? δ} : M _x for M = Na, K; x = 0.2, 0.3, and y = 0, 0.2. The microstructure was characterized by transmission electron microscopy with local energy-dispersive x-ray in situ analysis (probe size ～1 nm). An analysis shows that none of the doping elements (Na, K, or Cl) enters into 123 grains in sizable amounts and that, as a result, the critical temperature of the superconducting transition remains practically constant in the range 90.0–93.5 K. Potassium and chlorine segregate at grain boundaries. It is shown that grain-boundary segregation of chlorine leads to a substantial increase in the superconducting critical current (by a factor 3–5 at 70 K) as compared to the undoped sample. The possible mechanisms accounting for the effect of Cl on intergrain critical current are discussed.     

Investigation of the mechanism of inelastic deuteron scattering on <Superscript>12</Superscript>C at <Emphasis Type="Italic">E</Emphasis><Subscript>d</Subscript> = 15.3 MeV by the method of <Emphasis Type="Italic">dγ</Emphasis> angular correlations

The results are presented that were obtained by measuring the differential cross sections for the reaction ¹²C(d,d) ¹²C occurring at E _d = 15.3 MeV and leading to the production of a ¹²C nucleus in the ground and the first excited state. The energy dependences of the differential reaction cross sections were measured for three angles of deuteron emission in the range of projectile-deuteron energies E _d between 12 and 15.3 MeV. The double-differential cross sections for the reaction in question were measured for the 2⁺ state of the ¹²C nucleus at 4.44 MeV, and the angular dependences of the even spin-tensor components of the density matrix were determined, along with the angular dependences of the populations of magnetic sublevels and the components of the tensors of multipole-moment orientation. These experimental results are compared with their theoretical counterparts obtained under the assumption of various reaction mechanisms, including collective interaction, heavy-particle stripping, a two-step mechanism that takes into account the delay in the interaction, and the mechanism of compound-nucleus formation.