Study of the tautomerism of 4-cyano-3-thiophanone and 4-cyano-5-methyltetrahydro-3-furanone

The Meyer equation is satisfied for the 4-cyano-3-thiophanone-4-cyano-5-methyltetra-hydro-3-furanone pair in acetonitrile, alcohols, and aqueous dioxane. The Meyer equation is not satisfied for 4-cyano-3-thiophanone and 4-cyano-5-methyltetrahydro-3-furanone paired with-dicarbonyl compounds in acetonitrile, alcohols, and aqueous dioxane.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1620–1625, December, 1971.     

Proteome analysis using isoelectric focusing in immobilized pH gradient gels followed by mass spectrometry

Over the past several years, a large effort has been focused on improvements of two-dimensional (2-D) gel electrophoresis-based proteomics technology, and on development of novel approaches for proteome analysis. Here, we describe the application of an alternative strategy for the analysis of complex proteomes. The strategy combines isoelectric focusing in immobilized pH gradient strips (in-gel IEF), mass spectrometry (MS), and bioinformatics. A protein mixture is separated by in-gel IEF, and the entire strip is cut into a set of gel sections. Proteins in each gel section are digested with trypsin, and the tryptic peptides are subjected to liquid chromatography-nanoelectrospray-quadrupole ion-trap tandem mass spectrometry (LC-ESI-MS/MS). The LC-ESI-MS/MS data are used to identify the proteins through searches of a protein sequence database. Using this in-gel IEF-LC-MS/MS strategy, we have identified 127 proteins from a human pituitary. This study demonstrates the potential of the in-gel IEF-LC-MS/MS approach for analyses of complex mammalian proteomes.     

Chloro Complexes of Mercury(II) in Aqueous Perchlorate Media: Equilibrium and Electronic Absorption Spectra

The literature data on the equilibrium constants of formation of HgCl^– _{3 solv} and HgCl^2– _{4 solv} from HgCl_{2 solv} and Cl^– _solv in aqueous perchlorate–chloride solutions were generalized. The individual electronic absorption spectrum of the trichloro complex of mercury(II) was obtained for the first time, and the effect of the ionic strength on the spectra of di-, tri-, and tetrachloro complexes of mercury(II) was considered. The previously developed procedures for the resolution of absorption spectra into individual bands were found to be suitable for interpretation of spectral changes experimentally observed for solutions as the result of stepwise complexation. The parameters of the absorption bands in the spectra of chloro complexes of mercury(II) were determined.     

A new reaction of silica with pentafluoropropyonyl fluoride and perfluoropropylene oxide

Russian Journal of General Chemistry -     

Microwave, Submillimeter-Wave, and High-Resolution FTIR Study of SO(2)F(2) in the nu(8) State

The high-resolution infrared spectrum of the nu(8) band of SO(2)F(2) (nu(as) SF(2)) centered at 887.2 cm(-1) has been recorded with a resolution of 2.4 x 10(-3) cm(-1). More than 8000 transitions of the C-type band with DeltaK(a) = +/-1 (and in addition some DeltaK(a) = +/-3 transitions) have been assigned. Microwave and millimeter-wave spectra of the v(8) = 1 state up to 450 GHz have been recorded, and 177 pure rotational transitions have been measured. Rotational and rovibrational data have been combined, and excited state parameters up to sextic centrifugal distortion constants have been determined using a Watson-type Hamiltonian in S-reduction. No perturbation was indicated. Copyright 2000 Academic Press.     

Guided Projections for Analyzing the Structure of High-Dimensional Data

A powerful data transformation method named guided projections is proposed creating new possibilities to reveal the group structure of high-dimensional data in the presence of noise variables. Using projections onto a space spanned by a selection of a small number of observations allows measuring the similarity of other observations to the selection based on orthogonal and score distances. Observations are iteratively exchanged from the selection creating a nonrandom sequence of projections, which we call guided projections. In contrast to conventional projection pursuit methods, which typically identify a low-dimensional projection revealing some interesting features contained in the data, guided projections generate a series of projections that serve as a basis not just for diagnostic plots but to directly investigate the group structure in data. Based on simulated data, we identify the strengths and limitations of guided projections in comparison to commonly employed data transformation methods. We further show the relevance of the transformation by applying it to real-world datasets.     

The heat capacity of solid antimony telluride Sb<Subscript>2</Subscript>Te<Subscript>3</Subscript>

The literature data on the heat capacity of solid antimony telluride over the range 53–895 K were analyzed. The heat capacity of Sb₂Te₃ was measured over the range 350–700 K on a DSM-2M calorimeter. The equation for the temperature dependence was suggested. The thermodynamic functions of Sb₂Te₃ were calculated over the range 298.15–700 K.     

New approach to the synthesis of 1,3-dioxolanes

Application of ethanol to the synthesis of 1,3-dioxolanes by the condensation of carbonyl compounds with vicinal diols results in a high yield of the reaction product and considerably reduces the duration of the process. It is assumed that the effect of the ethanol is caused by the adduct formation with carbonyl compounds (hemiacetals) which behave as active intermediates of the condensation. A cyclic ketal of acetone with glycerol obtained with the help of ethanol was used as a basis component in the synthesis of a series of ketals substituting diol or carbonyl components by transketalyzation mechanism proceeding without water liberation.     

Thiourea stripping of rhodium from organic phases resulting from extraction with a mixture of dialkyl sulfide and alkylanilinium nitrate from acid nitrate-nitrite aqueous solutions of triaquatrinitrorhodium(III)

In continuation of our studies on the extraction of rhodium from acid nitrate-nitrite aqueous solutions with a mixture of alkylanilinium nitrate and dialkyl sulfide, a back-extraction of rhodium was studied. Thiourea (TU) is an efficient agent for the back-extraction of rhodium and concomitant noble metals (Pd, Ru, Ag). The back-extraction of rhodium proceeds via coordination mechanism, [Rh(tu)₆](NO₃)₃ being the major product. Aqueous 1 mol/L solution of TU ensures stripping of at least 91% rhodium and provides its relative concentrating up to 4 times (time of phase contact is 5 min, temperature 20?C35°C). The presence of palladium and other noble metals in extract does not affect the Rh stripping.     

Parallel global optimization of functions of several variables

On the basis of the method of nonuniform coverings, a parallel method for the global optimization of Lipschitzian functions is developed. This method is implemented in C-MPI for the global minimization of functions whose gradient satisfies the Lipschitz condition. The performance of the algorithm is demonstrated using the calculation of the structure of a protein molecule as an example.