Mass spectrometric study of the bromination of technical mixtures of polychlorinated biphenyls

The products of bromination of polychlorinated biphenyls (PCBs) that constitute Trichlorobiphenyl and Sovol PCB technical mixtures were studied by gas chromatography–mass spectrometry. On the basis of mass spectrometric data, the reaction was shown to result in formation of a mixture of poly(bromochloro)biphenyls containing from one to five bromine atoms and from two to six chlorine atoms in different combinations. It was found that the content of monobromo derivatives increases while the content of di-, tri-, and tetrabromo PCB derivatives decreases when the chlorination degree of the initial PCBs increases.     

Solvent-free reaction of 3-aryl-6-(3-nitrophenyl)-1,2,4-triazines with 4-(cyclohex-1-en-1-yl)morpholine

The aza-Diels–Alder reaction of 3-aryl-6-(3-nitrophenyl)-1,2,4-triazines with 4-(cyclohex-1-en-1-yl)morpholine as dienophile was accompanied by reduction of the nitro group to amino. In the reaction of 3-(4-methoxyphenyl)-6-(3-nitrophenyl)-1,2,4-triazine with 4-(cyclohex-1-en-1-yl)morpholine, 3-[3-(4-methoxyphenyl)-1,2,4-triazin-6-yl)aniline was formed together with the cycloaddition product.     

Pyrene-1-carboxylic acid polyethylene glycol esters: synthesis and photophysical studies

Russian Chemical Bulletin - Monoesters of tri- and tetraglycol and 1-pyrenecarboxylic acid were characterized for the first time by NMR spectroscopy and elemental analysis. The photophysical...     

Synthesis and antifungal activity of 3-substituted imidazo[1,2-<Emphasis Type="Italic">b</Emphasis>][1,2,4,5]tetrazines

A number of new 3-substituted imidazo[1,2-b][1,2,4,5]tetrazines containing azolyl, aminopyridyl, and alkoxyl substituents was synthesized. These compounds were studied for the biological activity against mycelial anthropophilic and zoophilous dermatophyte fungi (Trichophyton, Microsporum and Epidermophyton), causing diseases of skin and its appendages (hair, nails), and yeast-like fungi Candida.     

Structural analogs of adenosine receptor inhibitors in the series of 1,2,4-triazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidines

A universal method was developed for the synthesis of 7-alkylamino-6-nitro-1,2,4-triazolo-[1,5-a]pyrimidines by the chlorodeoxygenation of the corresponding triazolopyrimidones.     

Discontinuous solutions of the shallow water equations on a rotatable attracting sphere

The shallow water equations on a rotatable attracting sphere represent a system of hyperbolic equations on a compact manifold. These equations are derived in a spherical coordinate system from the integral laws of mass and total momentum conservation with account for the Coriolis and centrifugal forces. An analysis of the stability of discontinuous solutions with discontinuous waves and contact discontinuities is made using the closing law of total energy conservation, which represents a convex extension of the basic conservation-law system. The classes of stationary, one-dimensional (latitude-dependent only) exact solutions with contact discontinuities and discontinuous waves are constructed. Within the framework of the one-dimensional equations the test problem of wave flows resulting from the simultaneous break of two dams confining a fluid at rest in the vicinities of the poles is numerically modeled.     

Reactions of pyrazinium salts with phenols:from σ<Superscript>H</Superscript>-adducts to S<Subscript>N</Subscript><Superscript>H</Superscript>products and transformations into benzo[<Emphasis Type="Italic">b</Emphasis>]furans

The reaction of 5-(het)aryl-2,3-dicyano-1-ethylpyrazinium salts with phenol derivatives affords relatively stable dihydropyrazines, whereas the reactions of 6-(het)aryl-1,2,5-oxadiazolo[3,4-b]pyrazin-4-ium protic salts, depending on the phenol structure, result in products of nucleophilic substitution of hydrogen or open-chain transformation products: benzo[b]furan-substituted derivatives. The crystallographic data on the spatial structure of all types of the synthesized products were obtained.     

Chichibabin-type condensation of cyclic ketones with 3-R-1,2,4-triazin-5(4H)-ones

Reactions between substituted 1,2,4-triazines and ketones were investigated. General procedures for one-pot synthesis of hydrogenated derivatives of such polycyclic systems as benzo[c][1,2,4]triazino[1,6-a][2]azecine, [1,2,4]triazino[1,6-f]phenantridine, and dicyclopenta[b,d]pyrido[1,2-f][1,2,4]triazine are described.     

Regiodirected synthesis of polyfluoro-alkylated pyrimido[1,2-a]benzimidazoles

Conditions have been found for the regiodirected cyclization of 2-aminobenzimidazoles using ethyl 3-oxo-3-polyfluoroalkyl-2-ethoxymethylidenepropionates at the ethoxymethylidenefluoroacyl fragment to give ethyl pyrimidobenzimidazole-3-carboxylates.