Reactions of 2-phenylpyrrole with bromobenzoylacetylene on metal oxides active surfaces

The solvent-free interaction of 2-phenylpyrrole with bromobenzoylacetylene (room temperature) upon their grinding with solid metal oxides (MgO, CaO, ZnO, BaO, Al₂O₃, TiO₂, ZrO₂) and salts (CaCO₃, ZrSiO₄) leads to either the cross-coupling product or the adduct of pyrrole addition to the riple bond of acetylene. The ethynylation is accompanied by the formation of intermediate and side products: E-2-(1-bromo-2-benzoylethenyl)-5-phenylpyrrole and 1,1-di(5-phenylpyrrol-2-yl)-2-benzoylethene. The activity of the metal oxides in the ethynylation reaction falls in the order (in the brackets, the content of 2-benzoylethynyl-5-phenylpyrrole in the reaction mixture is given): ZnO (81%), BaO (73%), Al₂O₃ (71%), MgO (69%), CaO (50%). The oxides, SiO₂, TiO₂, ZrO₂, and the salts, CaCO₃ and ZrSiO₄, are inactive in the ethynylation reaction affording only the intermediate adduct, with ZrO₂ the isolated yield of the bromoethenylpyrrole reaching 60%. ESR monitoring shows the reaction to start from one electron transfer from pyrrole to acetylene mediated by the oxide surface. The adduct is readily converted on Al₂O₃ to 2-(benzoylethynyl)-5-phenylpyrrole crystallized mostly as cis-rotamer (X-ray data).     

On the formation of freak waves on the surface of deep water

Numerical simulation of the fully nonlinear water equations demonstrates the existence of giant breathers on the surface of deep water. The numerical analysis shows that this breather (or soliton of envelope) does not loose energy. The existence of such a breather can explain the appearance of freak waves. The text was submitted by the authors in English.     

Kolmogorov spectra in one-dimensional weak turbulence

In this article, we report the results of our numerical simulation of a one-dimensional modified MMT model, which includes the processes of “one-to-three” wave interactions. We show that this model, with properly chosen parameters, behaves according to the weak-turbulence theory. In particular, it demonstrates the validity of the Kolmogorov spectrum over a wide range of wave numbers.     

Regioselectivity of heterocyclization of 2-substituted 3,3-bis(methylsulfanyl)acrylo-nitriles with 2-benzimidazoleacetonitrile

Functionalized pyrido[1,2-a]benzimidazoles have been synthesized by the interaction of 2-substituted 2-cyano-3,3-bis(methylsulfanyl)acrylonitriles with 2-benzimidazoleacetonitrile under S _N Vin reaction conditions.     

Aliphatic aldehydes in the synthesis of carbo- and heterocycles. Part I. Synthesis of three-, four-, and five-membered rings

Data on the use of aliphatic aldehydes in the synthesis of three-, four-, and five-membered carbo- and heterocycles, published over the past 12 years, were summarized and systematized. Biological activity and synthetic utility of the resulting compounds was noted. The given data are classed according to the type of the ring formed.     

Total Nonnegativity of Infinite Hurwitz Matrices of Entire and Meromorphic Functions

In this paper we completely describe functions generating the infinite totally nonnegative Hurwitz matrices. In particular, we generalize the well-known result by Asner and Kemperman on the total nonnegativity of the Hurwitz matrices of real stable polynomials. An alternative criterion for entire functions to generate a Pólya frequency sequence is also obtained. The results are based on a connection between a factorization of totally nonnegative matrices of the Hurwitz type and the expansion of Stieltjes meromorphic functions into Stieltjes continued fractions (regular $C$ -fractions with positive coefficients).     

Synthesis of 3-cyano-5-ethoxycarbonyl-6-hydroxypyridine-2-thiol derivatives

Ethyl ethoxymethylenemalonate reacts with cyanothioacetamide andN-methylmorpholine to giveN-methylmorpholinium 3-cyano-5-ethoxycarbonyl-6-oxopyridine-2-thiolate. Alkylation of the latter yieldsS-alkyl derivatives. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 196–197, January, 1999.