Facile transformation of 2-azetidinones to 2-piperidones: application to the synthesis of the indolizidine skeleton and (8S,8aS)-perhydro-8-indolizinol

The highly functionalized bicyclic lactam 7 was prepared from diolefinic-2-piperidone 18 by the use of ruthenium-catalyzed RCM, and in turn, 18 was derived via a two-carbon addition process from readily accessible 4-olefinic-2-azetidinone 13. Bicyclic lactams 7 and 20 could serve as potentially valuable intermediates for the chiral synthesis of various hydroxylated indolizidine alkaloids as exemplified by the synthesis of (8S,8aS)-perhydro-8-indolizinol 19.     

Selective hydrogenation of dehydrolinalool and dehydrolinalyl acetate to linalool and linalyl acetate

Hydrogenation of dehydrolinalool and dehydrolinalyl acetate on 0.5% Pd/Al₂O₃ in C₂–C₅ alcohols of various structure has been studied at atmospheric and higher pressures of hydrogen. It is shown that the differences in selectivity of hydrogenation of dehydrolinalool to linalool and of dehydrolinalyl acetate to linalyl acetate is due to peculiarities in their structure.

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0,5% Pd/Al₂O₃ C₂–C₅ . , .

     

Photon polarization effects inb → sγg decay

We analyze the polarization properties of photons which are produced in the unpolarizedb-quark decay,bsg. Using the structure function formalism we carry out a general analysis of the polarization characteristics of in terms of the standard Stokes parameters. The expressions for five independent structure functions are constructed in terms of the weak magnetic transition form factors of the verticesbs andbsg. Numerical calculations of the Stokes parameters and various differential distributions forbsg are performed for the two-Higgs doublet model (2HDM). We studied the dependences of all these characteristics to the model parameters. These results were compared with the Standard Model predictions for different top quark masses. Strong sensitivity of the Stokes parameters, which defines the linear photon polarization, to the model is demonstrated.     

Photochromic properties of perfluorosulfonic membranes modified by sodium molybdate

Transfer of a perfluorosulfonic membrane from the hydrogen form into the sodium form provides accessibility of pore space to sodium molybdate aqueous solution. Charge transfer spectra make it possible to judge the course of polymerization of capsulated molybdate ions and its intensification when the membranes are held in HCl vapor. The UV irradiation of the modified membranes causes a progressing absorption in the visible spectral region. The rate and depth of photoreduction increase as the concentration and degree of polymerization of molybdate ions increase. The scheme of the process was offered, which is based on taking into account a possibility of delocalization of 4d ¹ electrons of molybdenum(V) over the system of metal-metal bonds.     

Specific features of indirect interaction in an impurity graphene bilayer in the framework of the s-d model

The specific features of the Ruderman-Kittel-Kasuya-Yosida interaction in an impurity graphene bilayer have been calculated in the framework of the s-d model. Hydrogen atoms are considered as impurities. The calculations have demonstrated that the antiferromagnetic impurity-spin ordering is preferable at short distances, while as the distance increases, the ordering becomes ferromagnetic. The dependences of the exchange interaction constant on the problem parameters are shown.     

Environmental effects on the geometric phase

The behavior of the geometric phase gained by a single spin-1/2 nucleus immersed into a thermal or a squeezed environment is investigated. Both the time dependence of the phase and its value at infinity are examined against several physical parameters. It is observed that for some intermediate ranges of the temperature and the coupling strength, the presence of squeezing enhances the geometric phase.     

Luminescence of terbium(III) chloride in porous glass

Terbium(III) chloride (1.5–150 μmol g^?1) was encapsulated in porous glass by impregnation of the support with aqueous solutions of various concentrations. The concentration dependences of the luminescence parameters and luminescence quenching in the course of water vapor adsorption in the salt intercalates were analyzed.