Quantitative determination of the electronic effects of 3- and 4-pyridazinyl groups from NMR spectral data for isomeric aminophenyl- and phenylpyridazines

The previously unknown aminophenylpyridazines were synthesized. The inductive and resonance constants of 3- and 4-pyridazinyl groups were calculated on the basis of ¹H and ¹³C NMR spectral data for isomeric aminophenyl- and phenylpyridazines in dimethyl sulfoxide (DMSO).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 951–958, July, 1986.     

Isomorphisms of geodesic flows on quadrics

We consider several well-known isomorphisms between Jacobi’s geodesic problem and some integrable cases from rigid body dynamics (the cases of Clebsch and Brun). A relationship between these isomorphisms is indicated. The problem of compactification for geodesic flows on noncompact surfaces is stated. This problem is hypothesized to be intimately connected with the property of integrability.     

Investigation of photoemission of polarized electrons from stressed superstructures

Photoemission of polarized electrons from heterostructures based on GaAs/AlInGaAs superstructures with minimum discontinuities of the conduction band edge and on AlGaAs/AlInGaAs superstructures with stressed quantum wells is investigated. A comparison of the experimental dependences of photoemission polarization on the excitation energy with the calculated dependences allows the polarization losses to be estimated in different photoemission stages. Record values of the polarization degree are reported. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 37–44, March, 2008.     

1H and 13C NMR study of azido-tetrazole tautomerism of 2-azido-4-methylpyrimidine

Using ¹H and ¹³C NMR and IR spectroscopic methods, it was found that 2-azido-4-methylpyrimidine exists in solutions in tautomeric equilibrium with two tetrazole forms, the ratio between which is determined by the polarity of the solvent, while in a crystalline state, according to the ¹³C NMR CP MAS data it has the structure of the 7-methyltetrazolo[1,5-a]pyrimidine isomer.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1648–1654, December, 1990.     

Alkylation and acylation of 2-aminopyrimidine N-oxides

Products of both O- and N-acylation are formed in the acylation of 2-aminopyrimidine N-oxides, whereas only O-alkylation products are formed by the action of alkylating agents. The reaction of 2-aminopyrimidine N-oxides with aldehydes gives only products of reaction at the amino group; the structures of the resulting compounds depend on the reactivity of the carbonyl component.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1515–1522, November, 1981.     

Benzimidazole derivatives with zwitterion structures

2-Pyridinium and β- and γ-picolinium-5,6-dinitrobenzimidazole betaines were obtained by reaction of 5,6-dinitro-2-chlorobenzimidazole with pyridine and β- and γ-picolines.     

Nucleophilic substitution in the azine series

This review is devoted to a discussion of the quantitative characteristics of the reactivities and mechanisms of the reactions of substituted azines with nucleophilic reagents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 723–734, June, 1973.