3-Indolizin-2-ylquinoxalines and the derived monopodands

The reactions of 3-acetylquinoxalin-2-one with methyl-and benzylpyridines in the presence of iodine produce the corresponding 3-(2-alkylpyridinioacetyl)quinoxalin-2(1H)-one iodides. Treatment of the latter with triethylamine affords the corresponding 3-indolizin-2-ylquinoxalin-2-ones. Due to the presence of the endocyclic carbamoyl group, the reactions of these compounds with bisalkylating reagents give quinoxaline-containing monopodands and monoalkylation products containing spacers with different lengths and of different nature. Dedicated to Professor Ya. A. Levin on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2534–2542, November, 2005.     

Energy states of colored particle in a chromomagnetic field

The unitary transformation which diagonalizes the squared Dirac equation in a constant chromomagnetic field is found. Applying this transformation, we find the eigenfunctions of the diagonalized Hamiltonian, that describes the states with a definite value of energy, and we call them energy states. It is pointed out that the energy states are determined by the color interaction term of the particle with the background chromofield, and this term is responsible for the splitting of the energy spectrum. We construct supercharge operators for the diagonal Hamiltonian that ensure the superpartner property of the energy states. PACS 03.65.-w An erratum to this article can be found at     

The construction of reciprocity and integral representation formulas of the general solution for quasistatic and dynamic problems of uncoupled generalized thermoelasticity

Reciprocity formulas are constructed and representations of the Somigliani-type are obtained for quasistatic and dynamic problems of uncoupled generalized thermoelasticity in the Lord-Shulman formulation that is effective for applications. Moreover, representations are obtained for the stresses and heat flux. Unlike the existing approach (/1/, say) these formulas are derived on the basis of an examination of the system of differential equations of the above-mentioned problems of generalized thermoelasticity as a system with appropriate non-selfadjoint differential operators. Operators adjoint to the initial differential operators are introduced into consideration for the construction of the reciprocity formulas (second Green's formula), and a Laplace transformation is used.     

The photolysis and radiolysis of H2S−CH4 gas-phase mixture

The purification of methane from hydrogen sulphide at room temperature as affected by U.V.-light and ionizing radiation has been studied. A probable reaction mechanisms is discussed.     

Deuteron electromagnetic form factors and tensor polarization observables in the framework of the hard-wall AdS/QCD model

We study the electromagnetic form factors and tensor polarization observables of the deuteron in the framework of the hard-wall AdS/QCD model. We find a profile function for the bulk twist \begin{document}$\tau=6$\end{document} vector field, which describes the deuteron on the boundary and fix the infrared boundary cut-off of AdS space in accordance with the ground state mass of the deuteron. We obtain the deuteron charge monopole, quadrupole, and magnetic dipole form factors and tensor polarization observables from the bulk Lagrangians for the deuteron and photon field interactions. We plot the momentum transfer dependence of the form factors and tensor polarization observables and compare our numerical results with those in the soft-wall model and experimental data.     

Vibrational distribution functions and relaxation rate in anharmonic-oscillator systems

Analytical expressions were derived for the vibrational distribution function in a system of anharmonic oscillators under conditions where the supply of vibrational energy considerably exceeded the equilibrium value. Distribution was found by considering the effect of vibrational-vibrational and vibrational-translational energy exchange, as well as spontaneous radiative transitions. Analytical expressions were also obtained for the relaxation rate of vibrational energy. It was shown that where there is a strong deviation from equilibrium this rate can significantly exceed the corresponding value for a model of harmonic oscillators and is determined by the probability of vibrational-vibrational exchange in the molecules.     

Manganese-depleted/reconstituted photosystem II core complexes in solution and liposomes

Chlorophyll fluorescence transients measurements were employed to study the functioning of spinach photosystem II (PS II) core complexes in solution or reconstituted into liposomes. Lipid vesicles were prepared from soybean phospholipids (asolectine) or a mixture of spinach thylakoid lipids. In comparison with intact PS II core complexes comprising two distinct fluorescence phases, designated as O-J and J-P, complete suppression of the latter phase in Mn-depleted samples was observed. An increase of magnitude of the J-P phase in the presence of exogenous MnCl(2) (4 Mn/RC) indicate in favor of partial restoring of oxygen-evolution activity of PS II. The J-P phase observed in PS II in solution was characterized by a lifetime of ~320 ms, while in liposome-reconstituted samples this phase was accelerated up to ~20 ms in case of asolectine and up to ~9 ms in case of a mixture of thylakoid lipids. These data clearly suggest that lipid environment stimulates the steady-state rate of oxygen evolution. The effect of lipids is likely based on keeping the embedded proteins in optimal structure for efficient functioning.     

Benzimidazoles and related heterocycles 10. A novel acid-catalyzed rearrangement in the system 3-(α-aminobenzyl)quinoxalin-2(1H)-one-ethyl acetoacetate as a simple and efficient method for synthesizing 2-(pyrrol-3-yl)benzimidazoles

A reaction of 3-(α-aminobenzyl)quinoxalin-2(1H)-one with ethyl acetoacetate in boiling acetic acid is accompanied by contraction of the pyrazine ring. A rearrangement involving the fragment C(2)-C(3)-C(NH₂)Ph of the quinoxaline system and the fragment C(2)-C(3) of ethyl acetoacetate yields 2-(4-ethoxycarbonyl-5-methyl-2-phenylpyrrol-3-yl)benzimidazole. Possible pathways of this reaction are considered.     

Pyrrolo[1,2-<Emphasis Type="Italic">a</Emphasis>]quinoxalines based on pyrroles (Review)

Published data on methods for the synthesis of pyrrolo[1,2-a]quinoxalines, based on derivatives of pyrroles and also on compounds not originally derivatives of quinoxalines or pyrroles, are reviewed and classified.