Reactions of 2,3-dioxopyrrolo[2,1-a]isoquinolines with sodium borohydride and the properties of its products

The reaction of 2,3-dioxopyrrolo[2,1-a]isoquinolines with sodium borohydride, depending on the conditions under which it is carried out, can proceed by the route of hydrogenation or by the opening of the pyrrole ring. In the latter case, ketoesters, for which examples of reactions at the dicarbonyl and enamine fragments are presented, are formed.Institute of Technical Chemistry, Urals Section (UrO), Russian Academy of Sciences (RAN), Perm' 614600. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 685–692, May, 1996. Original article submitted February 10, 1996.     

Effect of the composition and structure of the surface layer on the functional properties of a core(Al2O3)-Shell(VO x /TiO y ) composite

Molecular layering method was used to synthesize vanadium, titanium, and vanadium-titanium oxide structures of various compositions and structures on the surface of γ-Al₂O₃. The systems obtained and the starting aluminum oxide were identified by chemical-analytical and adsorption methods, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The catalytic properties of the products obtained were examined for the example of oxidative dehydrogenation of methanol. It is shown that the reactivity of the samples is affected not only by the concentration of catalytically active vanadium oxide structures, but also by their remoteness from the surface of the starting matrix, controlled by the thickness of the titanium oxide sublayer.     

Allylboration of isatin and 2,3-dioxopyrrolo[2,1-a]isoquinolines

The reaction of triallylboron with isatin and derivatives 2,3-dioxopyrrolo[2,1-a]isoquinolines at room temperature proceeds regiospecifically at the ketone group to give the corresponding homoallyl alcohol. One of these, which contains a lactam and an amide in its structure, was reduced with lithium tetrahydroaluminate to a diamine.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Institute of Technical Chemistry, Ural Branch, Russian Academy Sciences, Perm' 614000, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 908–915, July, 1998.     

Formation of defect density superlattices in binary compounds under nuclear irradiation

Manifestation of antisite defects in crystals under irradiation is studied. Calculations show that the concentration of such defects can reach high levels under typical irradiation intensities and temperatures. It is shown that buildup of antisite defects and interaction between them can result in instability of the system during irradiation with respect to spatially nonuniform perturbations. The instability should give rise to a periodic modulation of the density of antisite defects. The region of instability as a function of crystal parameters and irradiation has been obtained.     

Shadowing of sea surface at grazing radio-wave propagation

A model of a statistically inhomogeneous sea surface is proposed, within the scope of which a formula is derived for the probability of mirror-point nonshadowing. The presence of a statistical relationship between height and slope at the same point is essential for this. The correlation between sea-wave crests is taken into account in a simply connected Markov approximation. It is shown that the probability of nonshadowing rises with an increase in correlation. Dependence on distance is absent, with the exception of regions adjacent to the receiver and transmitter, where an increase followed by an abrupt drop in the nonshadowing probability is observed for small wave-crest correlation coefficients.Radio-Astronomy Institute, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 11, pp. 1355–1364, November, 1994.     

Modulation of radar signal reflected from rough surface by relief slope and soil electrodynamic-parameter inhomogeneities

The authors study variations of the specific effective scattering surface (SESS) of a radar signal reflected from a rough surface with small irregularities due to changes in the slopes of the small-scale relief and inhomogeneities of the complex permittivity of the soil in the case of a surface resolution element whose linear dimensions are much smaller than the characteristic scale of the relief. In the opposite case, formulas are derived for corrections to the SESS that are proportional to the variance of the slopes of the large-scale relief. It is shown that the correction for horizontal polarization is greater than that for vertical; the effect of the three-dimensionality of the relief roughness is also greater. A nonzero SESS for orthogonal polarization is due to the presence of relief slopes across the plane of incidence.Kharkov Radio-Astronomy Institute, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 4, pp. 444–457, April, 1994.