Synthesis of thermostable aliphatic alkylene-bis(N-phenyl aldonitrones)

A general method for the synthesis of alkylene-bis(N-phenyl aldonitrones) (bisnitrones) by reaction of dianions ofN,N-bisnitroacetyldiamines with nitrobenzene in DMF was proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2588–2590, October, 1996.     

A novel general method for the synthesis of nitrones by reaction of nitroso compounds with anions of aliphatic nitro compounds

Anions of aliphatic nitro compounds R¹R²C=NO₂ ^– react with nitroso compounds RNO to give nitrones R¹R₂C=N(O)R. Salts of nitro compounds with metals and Et₃N, as well as trimethylsilyl nitronates in the presence of F^–, can serve as the sources of the anions. The structure of the nitrones was established by NMR spectroscopy. 1,3-Dipolar cycloaddition of a series of the nitrones obtained to olefins was investigated.For a brief communication see Ref. 1Translated from IzvestiyaAkademii Nauk. Seriya Khimicheskaya, No. 4, pp. 901–907, April, 1996.     

Chemistry of N,N‐Bis(silyloxy)enamines,Part 5

Aliphatic nitro compounds can be considered as good precursors of a wide variety of α‐azolyl‐substituted oximes. The double silylation of convenient aliphatic nitro compounds and the subsequent N,C‐coupling of the resulting N,N‐bis(silyloxy)enamines 3 with N‐silylated azoles 4 lead to the formation of the silylated α‐azolyl‐substituted oximes 6 , which can be smoothly desilylated to give the target α‐azolyl‐substituted oximes 5 . The mechanism of the key step of this process – N,C‐coupling – includes the generation of corresponding conjugated nitrosoalkenes 7 (Schemes 4 and 5). The contribution of the chain mechanism in the overall process is considered as well. The studies of the scope and limitations of this reaction, as well as the optimization of its conditions were accomplished. The configuration of the CN bond in oximes was established by NMR.     

Dineutron configurations in neutron-excess nuclei from the viewpoint of the diffraction model

Cross sections measured for the interactions of incident neutron-excess nuclei ⁶He and ¹¹Li with other nuclei are analyzed in terms of expressions obtained for relevant integrated cross sections within the diffraction approximation. The results of this analysis suggest that there exists a dineutron configuration in the ⁶He nucleus and that there is no such configuration in the ¹¹Li nucleus. On the basis of calculations performed for various observables, some new specific experiments are proposed for discovering dineutrons more reliably in nuclei having a neutron halo.     

Electrophilic substitution of thetert-butyl-NNO-azoxy group by the bromine atom

The electrophilic substitution of thetert-butyl-NNO-azoxy group by the bromine atom was observed for the first time when 6-bromo-2,4-bis(tert-butyl-NNO-azoxy)-5-chloro-1,3-phenylenediamine was treated with bromine in AcOH. The structural factors promoting this reaction are discussed. The direction of the replacement was confirmed by PM3 calculations of the heats of formation of intermediate cationic σ-adducts. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2131–2134, November, 1999.     

Diffractive dissociation of tritons by incident protons

General expressions that are obtained in the present study for the differential cross sections describing the two-and three-body diffractive dissociation of tritons that is induced by intermediate-energy incident protons are used to calculate the energy distributions of neutrons and protons originating from this process and of scattered protons. The results are basically in satisfactory (but sometimes only qualitative) agreement with data from relevant coincidence experiments.     

Quasi-free inclusive processes in the two-particle splitting of tritons by deuterons with an energy of 37 MeV

The d + t → d + d + n reaction was experimentally and theoretically investigated at an incident deuteron energy of 36.9 MeV. The experiment was performed on the U-240 isochronous cyclotron at the Institute for Nuclear Research, National Academy of Sciences of Ukraine. Inclusive spectra of deuterons and their angular distributions in the range of 15° ≤ θ_d ≤ 52° were measured. Experimental spectra and angular distributions of the final deuterons from the d + t → d + d + n reaction are satisfactorily described in a diffraction approximation that considers interaction in the final state and the correct asymptotic of the wave function of colliding nuclei. The scattered deuterons are the main contributors to the cross section (up to 70–90%), while the deuterons from tritons can be seen well only at low and high energies, at the edges of the spectra.