Synthesis of <Emphasis Type="Italic">N</Emphasis>-Arylsulfonyl-α-thienylglycines from <Emphasis Type="Italic">N</Emphasis>-(2,2,2-Trichloro-1-thienylethyl)arenesulfonamides

Reactions of N-(2,2,2-trichloroethylidene)arenesulfonamides with thiophene, 2-chlorothiophene, and 2,5-dichlorothiophene, as well as of N-(2,2,2-trichloro-1-hydroxyethyl)arenesulfonamides with 2-chlorothiophene, lead to formation of the corresponding N-(2,2,2-trichloro-1-thienylethyl)arenesulfonamides. Alkaline hydrolysis of the latter occurs selectively at the trichloromethyl group to give N-arylsulfonyl-α-thienylglycines.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 93–96.Original Russian Text Copyright © 2005 by Aizina, Rozentsveig, Ushakova, Levkovskaya, Mirskova.     

Reaction of 1-Aryl-3-methylpyrazol-5-ones with 2-Cyanoaryldiazonium Bisulfates

2-Cyanoaryldiazonium bisulfates, obtained by the action of nitrosyl sulfuric acid on isatin 3-hydrazone and its 5-bromo and 5-nitro derivatives, couple with 1-aryl-3-methylpyrazol-5-ones and form 4-arylhydrazones of 1-aryl-3-methylpyrazole-4,5-diones. It was established on the basis of data of IR, UV, and ¹H NMR spectra and of X-ray structural analysis that the coupling products exist in the hydrazone form stabilized by an intramolecular hydrogen bond.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 210–215, February, 2005.     

TDDFT studies of electronic structure and first hyperpolarizability of terta-nuclear cubane-like transition metal clusters

The TDDFT method is first applied in a series of tetra-nuclear transition metal clusters studies for nonlinear optical properties. The results indicate that the charge transfer inside the metal core [MCu3X4] (M=W, Mo; X=S, O, Cl, Se, Br) makes contribution to the optical nonlinearity. It is possible to enhance the hyperpolarizability by substituting the ligands of the clusters.     

Observation of magnetic field effect on polymer yield in photoinduced dispersion polymerization of styrene

Photoinduced dispersion polymerization of styrene in the presence of dibenzyl ketone as a photoinitiator, with or without magnetic field, has been followed with time. The experiments were carried out at low degrees of conversion of monomer. Since the conditions of the polymerization reaction (viscosity of the medium, reagents concentration, etc.) were approximately unchanged, the results were explained on the basis of a simplified model of dispersion polymerization. The normal growth of the polymerization rates with temperature was registered, and the activation energy of the polymerization was estimated to be about 12 kJ/mol in the temperature range from 20 to 60 °C. The magnetic field effect was best seen at low temperature. The maximum yield of the polymerization product increases by 20% when the magnetic field of 1000 G was applied at the temperature of 20 °C.     

On the Intermittency in Nuclear Fragmentations

A simple Monte Carlo simulation and even a partition method can be used to reproduce quite well the power law behavior between the factorial moment and the charge interval of fragment charge distributions from the multifragmentation of ¹⁹⁷Au nucleus bombarding emulsion at～1 GeV/nucleon. This indicates that the above power law seems not to be a unique precursor of the intermittent behavior in nuclear multifragmentations.     

NUCLEAR CHARGE DISPERSION OF FRAGMENTS IN HIGH ENERGY PROTON-NUCLEUS COLLISION

The charge dispersion of fragments in high energy p+Cu,Kr and Xe reactions are calculated by statistical model and Monte Carlo technique.The corresponding data are reproduced quite well.It is shown that the charge dispersions are all nearly gaussian.The mass dependence of the most probable fragment charge reflects the rest target memory effect.     

EQUATION OF STATE OF HOT NUCLEI BEFORE BREAK-UP

Following the method developed by the authors,recently,the equation of state of hot nuclei(²³⁸U in concrete) before break-up was investigated numerically.The isotherms are drawn in the plan of the general pressure P versus volume V_RT. They are similar to those of Van der Waals gas.The critical temperature of phase transition should correspond to the isotherm with one turning point only.It turns out that the data of mass yield distribution can be reproduced by many pairs of parameters T and V_RT (freeze-out temperature and freeze-out volume) varying in certain range.For each isotherm (each T),the data are always best reproduced by the value of V_RT located at the maximum general pressure within two phases coexistence region.     

Synthesis of optically active analogs of α-tocopherol based on (S)-(+)-dihydromyrcene

New optically active analogs of α-tocopherol (vitamin E) were synthesized starting from enantiomerically enriched (ee≈50%) (S)-(+)-dihydromyrcene. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1631–1634, September, 2000.     

Λ Production and Λ/p Ratio in Relativistic Heavy Ion Collisions

The Λ multiplicity and Λ/p ratio are studied by hadron transportation-string fragmentation model in relativistic heavy ion collisions. Firstly, the dependence of Λ multiplicity and Λ/p ratio on the system size and the collision centrality is studied. It shows that the Λ and p multiplicities go up as the increase of system size and the increase of collision centrality. However, their ratio keeps almost a constant. The effect of Λ annihilation cross section to Λ multiplicity and Λ/p ratio is also studied. It is found that this effect is weak: Λ multiplicity and Λ/p ratio have a little amount of increase by the decrease of Λ annihilation cross section. Even the cross section is down to zero, Λ/p ratio is only 1.2 in 200A GeV AuAu head on collision. The Λ/p ratio is obtained to be 0.28 in pp collision, lying in the range of experimental data:0.2—0.3. It is also obtained that the ratio in AA collisions is 3—5 times of that in pp collision.     

The effect of anions in the coordination spherè of Mg complexes ofN-acetyldehydrophenylalanyl-(S)-valine on the diastereoselectivity of hydrogenation

Diastereoselective hydrogenation in ethanol over Pd/C ofN-acetyldehydrophenylalanyl-(S)-valine (1) as complexes with Mg salts of strong acids gives predominantlyN-acetyl-(S)-phenylalanyl-(S)-valine (de up to 60%). In the case of complexes of1 with Mg salts of weak acids, the sign of asymmetric induction changes. Data of¹⁹F NMR spectroscopy ofN-acetyldehydro(p-fluorophenylalanyl)-(S)-valine indicate that in the former case, the anion of a strong acid does not enter the coordination sphere of the complex, whereas in the larter case, the anion of the weak acid does. The nature of the solvent also influences the reaction stereoselectivity. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1704–1706, September, 1999.