Mass spectra of methoxy-substituted 4-aminopyrimidines

In a study of the mass spectra of methoxy-substituted 4-aminopyrimidines it has been shown that in the molecular ion the positive charge is predominantly concentrated on the oxygen atom of the methoxy group, which explains the appearance of the fragmentary ions (M-H)⁺ and (M-CH₂O)⁺. In contrast to the halopyrimidines, the molecular ion does not exist in the imine form, which is characteristic only for the fragmentary ions (M-CH₂O)⁺.     

Reaction of 2-methylpyrrolo[3,2-H]quinoline with N-acyl salts of heteroaromatic cations in situ

The reaction of pyrroloquinoline with N-acylpyridinium, N-acylquinolinium, N-acylisoquinolinium, and N-acylbenzimidazolium salts (formed as a result of the reaction with carboxylic acid chlorides), which leads to partially hydrogenated N-acyl derivatives of pyrroloquinoline, was investigated. The reaction of pyrroloquino-line with acridine hydrochloride, as a result of which its acridine derivative was obtained, was carried out.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 251–254, February, 1978.     

Study of the structure of an a-seco compound produced by the oxidation of ursolic acid

When ursolic acid was oxidized with potassium dichromate in the presence of sulfuric acid in glacial acetic acid, two new compounds were obtained. On the basis of the results of instrumental methods of analysis, structures have been suggested which correspond to 2-carboxy-5-hydroxy-11-oxo-3-oxaursa-1,12-dien-28-oic acid and 9-hydroxyl-11-oxo-2,3-secours-12-en-2,3,28-trioic acid 2,9-lactone.     

Condensed imidazo-1,24-azines. 28. Synthesis and transformations of 2-aroylmethyl-6,7.-diphenylimidazo-[1,2-b]-1,2,4-triazin-4H-3-ones

The reaction of 1,2-diamino-4,5-diphenylimidazole with 3-aroyl-2-propanonoic acid yields 2-aroylmethyl-6,7-diphenylimidazo[1,2-b]-1,2-4-triazin-4H-3-one. The cyclization pathways of these imidazoriazines leading to condensed furo[2,3-e]-, thieno[2,3-e]-, pyrrolo[2,3-e]-, and furo[3,2-e]limidazo[1,2,-b]-1,2,4-triazines were studied. A mass spectrometric study was carried out on the decomposition of these products upon electron impact. For Communication 27, see [1]. Kherson Industrial Institute, 325008 Kherson, Ukraine. A. N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 117071 Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 258–262, February, 1998.     

Resistance to Thermal Oxidative Degradation of Paraform-Modified Rosin and Its Derivatives

The resistance to thermal oxidative degradation of paraform-modified rosin and its derivatives (esters and salts) was studied. The modified rosin esters can be used as components of thermoplastic formulations, and modified salts, as heat-resistant additives to cutting fluids.     

Arylsulfonylation of N-isobutylaniline and its derivatives: experimental study and quantum-chemical calculations

The kinetics of the reactions of benzene-substituted N-isobutylanilines 1a—h with 3-nitrobenzenesulfonyl chloride in propan-2-ol was studied at 298 K. To analyze the reactivities of compounds 1a—h in the arylsulfonylation reactions and substantiate the possible mechanism of these reactions, the geometric, electronic, and energy characteristics of the reagents and a series of model compounds were calculated by the semiempirical quantum-chemical AM1 and PM3 methods. The rate of arylsulfonylation of N-isobutylaniline and its derivatives increases directly proportional to the contributions of the s and p _z orbitals of the N atoms to HOMO of amine and of the S atoms to LUMO of sulfonyl chloride. The coefficients of these AOs can be considered as the reactivity indices of the reagents used for arylsulfonylation of substituted N-isobutylanilines with aromatic sulfonyl chlorides. It was proposed that the reaction under study is orbital-controlled.     

Nucleophilic recyclization of β-carbolines — New variant of the synthesis of the carbazole ring

The reaction of salts of 1,3-dimethyl-9H-pyrido[3,4-b]indole with hydroxide ions was examined within the framework of the Pariser-Parr-Pople (PPP) method. It is shown that the reaction may stop at the step involving the formation of an anhydro base (R = H) or lead to recyclization products (R = CH₃, C₂H₅), viz., carbazole derivatives. The calculated data are in good agreement with the experimental data.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 197–203, February, 1984.     

Dissociative ionization of fusidic acid and the products of its thermolysis in the temperature range of 30–250°C

The results are reported of a study of the dissociative ionization of fusidic acid and its derivatives, and also of an investigation of the products of its thermal degradation by the mass-spectrometric method. A scheme of fragmentation of the antibiotic under the action of electron impact is suggested.All-Union Scientific-Research Institute of Antibiotics, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 228–234, March–April, 1981.     

Mass spectrometry of nitrogen heterocycles. 2. Correlation of mass spectrometric fragmentation processes and chemical aromatization reactions of dihydroazines

The results of mass spectrometric studies of aromatization processes of dihydroazines have been compared with experimental data relative to their chemical oxidation. The results of electron impact induced ionization of dihydroazines can be correlated directly with the direction of chemical oxidation.For Communication 1, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1083–1087, August, 1989.     

Impedance of a passive iron electrode in a solution containing a reducing agent

Frequency dependences of impedance of a passive iron electrode in 0.5 M Na₂SO₄ solutions with and without 0.01 M K₄[Fe(CN)₆] are obtained by a pulsed method and the Fourier transform. At 1–1000 Hz, the results in 0.5 M Na₂SO₄ satisfactorily agree with our previous results obtained by a lock-in method. With the [Fe(CN)₆]^4- ions present, the impedance decreases faster at lower frequencies. The impedance of the oxide film/solution interface relaxes longer the film impedance. These conclusions are similar to those obtained earlier.Translated from Elektrokhimiya, Vol. 41, No. 1, 2005, pp. 97–101.Original Russian Text Copyright © 2005 by Klyuev, Rotenberg, Batrakov.To the Centennial of B.N. Kabanov.