Substituted pyridines. 2, 5-Dimethyl-4-p-nitrobenzylpyridine and its reactions

2, 5-Dimethyl-4-p-nitrobenzylpyridine has been prepared. Its nitro group has been reduced and its methylene group oxidized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp 1225–1227, September, 1970.     

Reduction of ester groupings in porphyrins with sodium borohydride

Reduction of the corresponding acyl derivatives by means of sodium borohydride [1, 2] is usually employed to obtain porphyrins with -hydroxyalkyl substituents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, p. 860, June, 1973.     

Porphyrins. 39. Synthesis and Chemical Transformations of Porphyrins and Chlorins with 2-Acetyl-1-methyl-3-oxobutyl Substituents

Porphyrins and chlorins containing acetylacetone residues in the peripheral substituents [-CH(Me)CHAc₂] are converted under alkaline conditions into the corresponding deacetylated compounds with [-CH(Me)CH₂Ac] residues. Reduction of the latter as acids using sodium borohydride gives the corresponding alcohols and, after esterification, their acetates with branched peripheral [-CH(Me)CH₂CH(OAc)Me] substituents. Porphyrins and chlorins with such substituents in water-soluble form may hold interest as new photosensitizers in photodynamic cancer therapy.     

Frequency dependence of potentials of minimum capacitance for electrodes of copper subgroup metals in alkali halide melts

The electrochemical impedance technique was use to obtain the potentials of the minimum capacitance of Cu, Ag, and Au electrodes in chlorides, bromides, and iodides of sodium, potassium, and cesium. Their dependence on the nature of the metal and electrolyte, temperature and ac signal frequency is studied. It is shown that the potential of the minimum capacitance tends at a decrease in the frequency to the zero charge potential measured under similar conditions. An assumption is ventured that the cause of this may be specific adsorption of halide ions on the electrode in the form of negatively charged dihalide complexes. It is found that in the systems where two minimums are observed, a decrease in the spacing between the cathodic and anodic minimums correlates with an increase in the strength of the metal-adsorbate bond.     

On the governing equations for the compressing process and its coupling with other processes

As a continuation of a recent linear analysis by Mao et al.(Acta Mech Sin,2010,26:355),in this paper we propose a general theoretical formulation for the compressing process in complex Newtonian fluid flows,which covers gas dynamics,aeroacoustics,nonlinear thermoviscous acoustics,viscous shock layer,etc.,as its special branches.The principle on which our formulation is based is the maximally natural and dynamic Helmholtz decomposition of the Navier-Stokes equation,along with the kinematic Helmholtz decompos...     

Scattering of conduction electrons in Fe(t x , Å)/Cr(10 Å) superlattices with ultrathin iron layers

IR magnetoreflection spectra, diagonal σ _xx and off-diagonal σ _xy components of the effective optical conductivity tensor, and magnetic properties of Fe(t _x , Å)/Cr(10 Å) superlattices have been studied. The abrupt decrease in the amplitude of dissipative function ?ωImσ _xy (ω) (ω is the cyclic frequency of light wave) in the superlattices with ultrathin Fe layers (t _Fe = 3.2, 2.6, 2.1 Å) has been analyzed. It has been found that the magnetorefractive effect in nanostructures with ultrathin iron layers is due to scattering of conduction electrons by magnetic interfacial layers formed in the Cr matrix with complete consumption of deposited iron atoms. The parameters of the interfacial scattering of electrons in the spin-up (└) and spin-down (┌) conduction channels have been discussed.     

X-ray diffraction examination of o-carboranes with tert-butyl and trimethylsilyl substituents

Conclusions By a complete x-ray diffraction examination of 1-tert-butyl-o-carborane (I) and 1-trimethylsilyl-2-methyl-o-carborane (II), it was found that the bonds between the substituants and the icosahedral skeleton are elongated. The tert-butyl substituent in (I) has a screened orientation with respect to the nearest pentagonal fragment, and the trimethylsilyl substituent in (II), a screened orientation with respect to the boron atoms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2481–2487, November, 1979.     

1,3-Thiazinediones and pyrimidine diones

2-Methyl- and 2-alkoxy-4,6-dioxodihydro-1,3-thiazines were synthesized. A comparative examination of the IR and PMR spectra of 2-substituted thiazinediones and their O-methyl ethers and sodium derivatives was made. It is shown that a change in the character of the substituent has a substantial effect on the structure of the /S-dicarbonyl fragment.Translated from Khimiya Geterotsiklichesikih Soedinenii, No. 8, pp. 1042–1046, August, 1976.     

Effect of heavy atoms in bioluminescent reactions

Bioluminescent reactions of luminous organisms are excellent models for studying the effects of heavy atoms on enzymatic processes. The effects of potassium halides with halide anions of different atomic weight were compared in bioluminescent reactions of the firefly (Luciola mingrelica), a marine coelenterate (Obelia longissima), and a marine bacterium (Photobacterium leiognathi). Two mechanisms of the effects of the halides were examined—the physicochemical effect of the external heavy atom, based on spin–orbit interactions in electron-excited structures, and the biochemical effect, i.e. interactions with the enzymes resulting in changes of enzymatic activity. The physicochemical effect was evaluated by using photoexcitation of model fluorescent compounds (flavin mononucleotide, firefly luciferin, and coelenteramide) of similar structure to the bioluminescence emitters. The bioluminescent and photoluminescent inhibition coefficients were calculated and compared for the luminous organisms to evaluate the relative contributions of the two mechanisms. The biochemical mechanism was found to be dominant. Hence, the bioluminescent reactions can be used as assays to monitor enzyme inhibition, in metabolic processes, by Br or I-containing compounds.