Synthesis of 2-aryl-4-azaindan-1,3-diones and 2-aryl-4-aza-5,6-benzindan-1,3-diones

Condensation of 2-hydroxymethylnicotinic and 2-hydroxymethylquinoline-3-carboxylic acid lactones with aromatic aldehydes in the presence of sodium methoxide gives, respectively, 2-aryl-4-azaindan-1,3-diones and 2-aryl-4-aza-5,6-benzindan-1,3-diones. Alkylation of 2-aryl-4-azaindan-1,3-diones with diazomethane gives the N-methylbetaines. According to the IR spectra, in the solid state the 4-azaindan-1,3-diones seemto have a strongly polarized enol structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 5, pp. 647–650, May, 1970.     

Effect of the heteroatom on the energies of the boundary molecular orbitals of dibenzo derivatives of five-membered heterocycles

The effect of the heteroatom on the energy characteristics of their boundary molecular Orbitals was studied by investigation of the charge-transfer complexes (CTC) of the dibenzo derivatives of five-membered heterocycles. Tetramethyl-substituted dibenzo derivatives of five-membered heterocycles were investigated as electron donors, and their corresponding dianhydrides were investigated as electron acceptors. Their ionization potentials and electron affinities, respectively, were determined. From the regularities in the change in these characteristics it was concluded that replacement of one heteroatom by another leads to approximately identical energy shifts of both boundary molecular orbitals.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 185–187, February, 1979.     

Phthalones and their structural analogs (review)

This review is devoted to research on the synthesis, reactivities, practical application, and structural problems of compounds of the phthalone series, primarily pyrophthalones and quinophthalones. The properties and peculiarities of the structures of the indicated compounds are compared with structural analogs that contain other heterocyclic substituents and other β-dicarbonyl systems and also with other betainelike derivatives of β-dicarbonyl compounds. Problems in the development of the chemistry of phthalones are discussed.     

Electronic absorption spectra and protolysis of 4- and 5-azaindan-1,3-diones

The protolytic equilibria in a series of 2-aryl-substituted 4- and 5-azaindan-1,3-diones and the corresponding N-methylbetaines and 5,6-benzo analogs were studied by spectrophotometry. The substantial difference between the 4- and 5-aza derivatives is explained by the different effect of the anionic system on the Tr-electron density and the reactivities of the nitrogen atoms in the 4 and 5 positions. The protonation and deprotonation constants of the dipolar ions correlate linearly with the constants of the substituents in the 2-phenyl ring. In the case of 5,6-benzo-4-azaindan-1,3-diones, the keto group of the azaphthaloyl ring is protonated along with the dipolar ion in strongly acidic media.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1382–1386, October, 1972.     

Interaction of a Traveling Pressure Perturbation with a Boundary Layer

The interaction between a traveling pressure perturbation and a laminar compressible boundary layer is investigated for a perturbation level higher than that needed to initiate steady-state flow separation. It is found that if the velocity of the pressure perturbation is fairly high the flow may remain unseparated and its direction of motion determines the nature of the perturbation propagation in the boundary layer. It is shown that even in the linear approximation the perturbations are mainly induced by the linear wall layer and not by the critical layer, which always remains nonlinear. It is also found that in the unsteady case shortwave perturbation oscillations are damped with time while the longwave ones grow and that the growth of the perturbations with time amplifies their damping along the streamwise coordinate while damping reduces it.     

Synthesis and solvatochromic and acid-base reactions of a betaine and salts of 4-N-pyridiniumcatechol

Oxidation of catechol by phenyliodosyldiacetate in the presence of pyridine gives 4-N-pyridiniumcatechol salts whose structures are confirmed by an independent synthesis from 2,2-dimethyl-5-aminobenzodioxole. The spectroscopically determined ionization constants for the 4-N-pyridiniumcatechol cation depend on the nature of the buffer cation solution (sodium, ammonium, tetraethylammonium). The large solvatochromic shift in the long wavelength absorption band of the betaine of 4-N-pyridinium-catechol followed the empirical scale of solvent polarity E_T ^N. Introduction of the N-pyridinium group in position 4 increases the acidity of the catechol by 2.7pK units, which is an almost identical effect to the introduction of a 4-nitro group. However, the solvatochromism for the anion of 4-nitrocatechol is insignificant. The compounds were characterized by their ¹H NMR and IR spectra.Translated fromKhimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1653–1661, December, 1993.     

Propagation of perturbations upstream with interaction between a hypersonic flow and a boundary layer

It is shown that, for hypersonic flows with moderate and strong degrees of interaction, perturbations brought about, for example, by a bottom opening or by any other sort of obstacle are propagated up to the leading edge of a solid body. Local regions with very large pressure gradients cannot arise in the flow. This is connected with the possibility of the development of breakaway zones with a length on the order of magnitude of the size of the solid body, described in the first approximation by the equations of the boundary layer. From a mathematical point of view the problem comes down to establishing the nonsingular nature of the solution near the leading edge, and to finding eigensolutions which make it possible to satisfy the boundary conditions at the trailing edge of the solid body. It is shown that, with a weak interaction between the hypersonic flow and the boundary layer, there may arise short flow regions with free interaction and locally nonviscous flows with large pressure gradients, within the limits of which the perturbations may move upstream.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 40–49, July–August, 1970.In conclusion, the author thanks V. V. Sychev for his evaluation of the problem.     

Asymptotic solutions of the Navier-Stokes equations in regions with large local perturbations

There are many problems of the dynamics of viscous flows of liquids and gases at high Reynolds numbers for the solution of which the classical theory of the boundary layer cannot be used. This applies, in particular, to all the problems with various sorts of local singularities in the stream-flows in the vicinity of corners, in regions of interaction of the boundary layer with an incident shock, flows near points of separation or attachment of the stream, etc. The purpose of the present paper is to attempt the theoretical investigation of problems of this type on the basis of the general analysis of the asymptotic behavior of the solutions of the Navier-Stokes equations. In order to do this, use is made of the familiar method of the construction and splicing of a combination of asymptotic expansions representing the solutions in the various characteristic regions of the stream with viscosity decreasing without bound [1].As an example, detailed consideration is given to the problem of viscous supersonic flow near a wall with large local curvature of the surface.