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1.
Yuliya E. Ryzhkova Fedor V. Ryzhkov Michail N. Elinson Oleg I. Maslov Artem N. Fakhrutdinov 《Molecules (Basel, Switzerland)》2023,28(1)
Chromeno[2,3-b]pyridines are substances demanded in medicinal and material chemistry. PASE (pot, atom, and step economy) and in particular one-pot approaches are key green chemistry techniques that are applied for the synthesis of heterocyclic compounds. In this case, the PASE approach was extended with ‘component economy’, as solvent was used also as reactant (solvent-involved reaction). This approach was adopted for the one-pot synthesis of previously unknown O-substituted 5-alkoxy-5H-chromeno[2,3-b]pyridines via two-step transformation, namely the reaction of salicylaldehydes and malononitrile dimer, with the subsequent addition of alcohol. The mechanistic studies revealed the possibility of concurrent reaction. The studies aided in optimizing the reaction conditions for the best yields (77–93%). Thus, the one-pot reaction proceeds efficient and quickly, and the work-up procedure (only simple filtering) is very convenient. The structure of synthesized chromeno[2,3-b]pyridines was confirmed by 2D NMR spectroscopy. 相似文献
2.
Ryzhkov LR 《The Journal of organic chemistry》1996,61(8):2801-2808
Thermal decomposition of a primary alkyl diacyl peroxide 2 is investigated. Dependence of product yields on temperature, viscosity, and solvent polarity is examined in a variety of media. The excess of the alkene disproportionation product 4 and the presence of ester 3 and acid 5 is argued to demonstrate the existence of a discrete acyloxy-alkyl geminate radical pair. Stereoselective deuterium labeling of 2 and subsequent (1)H-NMR analysis of the resulting isotopomers of 4 confirm the radical nature of detected decomposition products. 相似文献
3.
I. I. Ryzhkov 《Fluid Dynamics》2013,48(4):477-490
Long-wave instability that arises in a plane multicomponent mixture layer with the Soret effect is investigated. The layer is heated from above or below in the gravity field. The solution of the linearized equations of motion is sought in the form of a series in powers of the wave number assumed to be small. For the mixture with an arbitrary number of components the critical parameters of instability are determined. For binary and ternary mixtures the stability maps are plotted. The regions where the long- and short wave perturbations are the most dangerous are distinguished in the space of physical parameters. The analytical results are compared with the numerical solution of the linearized equations over a wide wave number range. As an example, instability in a ternary hydrocarbon mixture is considered. 相似文献
4.
V. V. Kuzenov S. V. Ryzhkov 《Bulletin of the Russian Academy of Sciences: Physics》2016,80(5):598-602
A combined scheme of hot plasma confinement is proposed, and laser and plasma-based methods for generating a megagauss field during the implosion of a magnetized target are described that allow the development of new high-density plasma sources for materials science experiments and advanced areas of power engineering. A procedure for numerical calculation of the physical processes involved in the target plasma in an external magnetic field is presented. 相似文献
5.
Using the discrete variation procedure we investigated the electronic structure, charge distributions, and chemical bonding in solid solutions of variable composition based on -Si3N4 with Si substituted by Al and N substituted by O (the general composition
). The electronic processes at the initial stage of SiAlON formation were studied (x = 1, 2) considering different distributions of Al–O pairs in the lattice of -Si3N4. The distribution mode of the dopant is found to be a more significant factor affecting the electronic structure of sialons compared to increased Al–O content; in particular, clusterization of dopant pairs leads to increased forbidden gap and splitting of the upper and lower valence bands. The results of calculations are used to interpret the systematic variations in the functional properties of -sialons depending on their chemical composition. 相似文献
6.
7.
In the self-consistent-field approximation, a statistical theory is constructed for the atomic distribution in the near-surface region of a binary alloy which is able to disintegrate from the atomically smooth free surface of the crystal. The form of the surface-segregation functions of the components is found, in closed form, taking the relaxation of the coordination energies and the atomicinteraction energies at the surface into account. The possibility of the existence of metastable nonmonotonic concentrational profiles at the crystal surface is demonstrated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 51–56, December, 1981. 相似文献
8.
A new approach to solve the inverse problem of the non-stationary chemical kinetics by a reparametrization of the initial
model is suggested. This approach permits to obtain all solutions of IP in the case of a finite number or some parametric
functions in the case of the infinite number of solutions. 相似文献
9.
10.
M. V. Ryzhkov D. L. Novikov V. G. Zubkov V. A. Gubanov 《Journal of Structural Chemistry》1989,30(5):713-716
The cluster method of discrete variation was used to study compounds containing chains of plane-coordinated copper ions separating oxygen-copper planes. We also examined real YBa2Cu3O7 and hypothetical MBa3Cu4O9 systems (M is a tetravalent metal ion). A study was carried out on the transformation of the valence band and structure of the molecular orbitals in the Fermi level in going from YBa2Cu3O7 to MBa3Cu4O9. The chemical bonding was analyzed and the role of the interchain interaction in the bonding of the copper and oxygen atoms in different crystallographic positions was determined.Institute of Chemistry, Urals Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 5, pp. 17–20, September–October, 1989. 相似文献