Synthesis of the ethyl ester of the mononitrile of malonic acid by the catalytic carbonylation of benzenesulfonyloxyacetonitrile

A new method has been developed for the synthesis of the ethyl ester of the mononitrile of malonic acid by the carbonylation of benzenesulfonyloxyacetonitrile in absolute ethanol in the presence of cobalt carbonyl. The yield of the desired product was 30% with 60–90% conversion of the starting compound. The effects of temperature, pressure, and reaction time were studied.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. S. M. Kirov Urals Polytechnical Institute, Ekaterinburg. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 215–216, January, 1992.     

Estimation scheme for level-dependent uncertainty of analytical result: application for determination of 1-hydroxypyrene in urine

The estimation scheme of uncertainty of determination of 1-hydroxypyrene (1-OHP) in urine was developed analysing the main stages of the analytical procedure: (1) preparation of 1-OHP standards, (2) creation of the calibration curve for the high performance liquid chromatography (HPLC) analysis method with the evaluation of recovery, (3) measuring procedure of aliquot of urine, (4) adjusting the pH of aliquot and hydrolysis with enzyme, (5) solid phase extraction, (6) concentration of the extract, (7) injection of the extract to chromatograph and analysing by the HPLC method, (8) calculation of 1-OHP mass from the calibration curve, (9) calculation of 1-OHP concentration in urine. The evaluation of the uncertainty is based on quantification of individual components. Combined uncertainty was calculated using the law of propagation of uncertainties according to the EURACHEM/CITAC guidelines. Level dependence of the uncertainty arises from the calibration curve. The limits of detection and quantification were found to be equal to 0.03 and 0.1 ng/mL, respectively. The calculated expanded level-dependent uncertainty covers 47–27–25% within the concentration range 0.03–0.1–0.4 ng/mL with the materials and equipment used. These parameters could easily be recalculated according to the proposed scheme if there are some changes in the analysis procedure.     

IR Photolysis of Liquid Hexamethyldisiloxane by Pulse CO2Laser Radiation

The IR photolysis of liquid hexamethyldisiloxane [(CH₃)₃Si]₂O by pulse CO₂laser radiation was studied. The experiments were performed both with and without a graphite powder as a sensitizer. The presence of the graphite sensitizer increases the efficiency of dissociation. To provide the highest penetration of the laser emission into a medium, the irradiation of samples were carried out with tuning far from the maximum of the Si–O bond absorption band (1055 cm^–1) using the 10P16 line (_las= 947.78 cm^–1). This tuning makes it possible to separate the process of IR multiphoton dissociation of the vapor over the liquid phase and to carry out the reaction in the liquid at a low (1 J/cm²) energy fluence of laser radiation. The IR spectra of irradiated liquid samples indicate the formation of linear and cyclic polystructures.     

Laser-spectrochromatographic identification of isomer in mixture

The combined “Gas Chromatograph — Laser Optoacoustic Spectrometer” (GC-LOAS) has been used to perform selective analysis of a mixture of fatty acid esters stereocisomers and a mixture of methylcyclopentadiene positional isomers. The GCLOAS system allows simultaneous recording of the retention time of the components in the mixture under analysis and their IR absorption spectra in the spectral operating range of the ¹²CO₂, ¹³CO₂ and HeNe lasers. It has been shown that the hydrogenated sample of fatty acids contains a lot of trans-isomer. Its content has been quantitatively estimated. The identification of methylcyclopentadiene isomers (both monomers and dimers) has been carried out, too.     

Reactivity of 5,10:8,14-Disecosteroids: An unusual rearrangement of cyclodecene-1,4-dione systems to five-membered-ring spiro-γ-lactones

Upon heating in AcOH, the stereoisomeric (Z)- and (R)-6,9-dioxocyclodex-3-enyl derivatives, 5 and 6 , respectively, obtained by HgO/I₂ oxidation of 5-hydroxy-8-oxo-8,14-seco-5α-androstane-3β,17β-diyl diacetate ( 3 ), undergo an unusual intramolecular rearrangement to give the corresponding unsaturated (5R,9R)- and (5R,9S)-spiro-lactones 7 and 8 , respectively. Hydroxylation of the C?C bond in 7 and 8 , and subsequent glycol cleavage of the resulting diols 9 and 10 afforded the epimeric spiro-lactones (5R,9S)- 11 and (5R,9R)- 14 , respectively, and in both cases, the ring-D-containing fragments 12 and 13 .     

The Root Class Residuality of the Tree Product of Groups with Amalgamated Retracts

Siberian Mathematical Journal - Given a root class $\mathscr{K}$ of groups, we prove that the tree product of residually $\mathscr{K}$ -groups with amalgamated retracts is a residually...     

X-ray fluorescence method for determining the mass absorption coefficient in two-layer thin-film Ti/Ge and Ni/Ge systems

We propose a new method for determining the mass absorption coefficient in x-ray fluorescence analysis of two-layer thin-film Ti/Ge and Ni/Ge systems using easily made standardized film layers obtained by deposition of titanium or nickel on a polymer film substrate. We calculate correction factors taking into account absorption of primary emission from the x-ray tube and absorption of the analytical line for an element of the bottom layer in the top layer.     

NEW SEMISYNTHETIC CEPHALOSPORINS WITH ANTIBACTERIAL,ANTIVIRAL AND ANTIFUNGAL ACTIVITY

Abstract

The synthesis of new derivatives of thiazolidine 2-alkylidene-4-on-5-acetamidocephalosporanic acids or thiazolidine 2-arylidenazino-4-on-5-acetamidocephalosporanic acids and their salts of general formula (I) has been achieved.     

On the Protein Fibrillation Pathway: Oligomer Intermediates Detection Using ATR-FTIR Spectroscopy

Oligomeric intermediates on the pathway of amyloid fibrillation are suspected as the main cytotoxins responsible for amyloid-related pathogenicity. As they appear to be a part of the lag phase of amyloid fibrillation when analyzed using standard methods such as Thioflavin T (ThT) fluorescence, a more sensitive method is needed for their detection. Here we apply Fourier transform infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode for fast and cheap analysis of destabilized hen-egg-white lysozyme solution and detection of oligomer intermediates of amyloid fibrillation. Standard methods of protein aggregation analysis— Thioflavin T (ThT) fluorescence, atomic force microscopy (AFM), and 8-anilinonaphthalene-1-sulphonic acid (ANS) fluorescence were applied and compared to FTIR spectroscopy data. Results show the great potential of FTIR for both, qualitative and quantitative monitoring of oligomer formation based on the secondary structure changes. While oligomer intermediates do not induce significant changes in ThT fluorescence, their secondary structure changes were very prominent. Normalization of specific Amide I region peak intensities by using Amide II peak intensity as an internal standard provides an opportunity to use FTIR spectroscopy for both qualitative and quantitative analysis of biological samples and detection of potentially toxic oligomers, as well as for screening of efficiency of fibrillation procedures.