bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and antiviral activity of stereoisomeric eritadenines
Authors: Holý Antonín , Votruba Ivan , De Clercq Erik
Published: August 2011

D-Eritadenine (Ia) and L-eritadenine (IIa) were prepared from 5-(adenin-9-yl)-5-deoxyaldofuranoses or enantiomeric 2,3-disubstituted erythronolactones (VIIIb, c, XIV). Oxidation of methyl 2,3-O-isopropylidene-D-ribofuranoside (IX) with periodate in the presence of ruthenium, followed by acid hydrolysis and reduction with sodium borohydride, afforded L-ribonolactone (XI). Its 2,3-O-isopropylidene derivative was subjected to alkaline hydrolysis, followed by oxidation with periodate, reduction with sodium borohydride and reaction with cyclohexanone to give 2,3-O-cyclohexylidene-L-erythronolactone (XIV). Condensation of [U-14C]-adenine with VIIIb, followed by acid hydrolysis, afforded [U-14C-adenine]-D-eritadenine. The threo-eritadenines III and IV were prepared by oxidation of 1-(adenin-9-yl)-1-deoxy-2,3-O-isopropylidenethreitols XVI and XVII with sodium periodate in the presence of ruthenium, followed by acid hydrolysis. Reaction of 9-(2,2-diethoxyethyl)adenine (XIX) with malonic acid gave 4-(adenin-9-yl)-3-butenoic acid (XXI); its methyl ester XXII, prepared by treatment with methanol, was isomerized with triethylamine to give methyl 4-(adenin-9-yl)-2-butenoate (XXIII). Hydroxylation of XXIII with osmium tetroxide afforded the racemic mixture of D- and L-threo-eritadenine (III+ IV). Eritadenines Ia and IIa were active against vaccinia, measles and vesicular stomatitis virus. Eritadenine Ia was also effective against reo- and parainfluenza virus. In general, the antiviral activity of the eritadenines decreased in the order D-erythro (Ia) > L-erythro (IIa) > D- and L-threo (III, IV).
Temperature-dependence of electrochemical kinetic parameters: Electrode reaction of the Zn(Hg)/Zn(II) system
Authors: Kang S. , Matsuda K. , Tamamushi R.
Published: August 2011

The electrochemical kinetic parameters of the D.M.E./Zn(II) electrode reaction in aqueous solutions containing perchlorate, nitrate, chloride and bromide ions were measured at different temperatures (5-50 °C) by the modified square-wave polarographic technique. The Arrhenius activation parameters and thermodynamic quantities of the electrode reaction were determined from the temperature dependence of the rate constant and conditional potential, respectively. Empirical correlations were observed between some pairs of kinetic and thermodynamic quantities.
Function of flavins in photolysis of bilirubin in vitro
Authors: Knobloch Eduard , Hodr Roman , Herzman Jiří , Houdková Věra
Published: August 2011

In the course of photochemical oxidation of bilirubin, riboflavin works as a reversible electron acceptor undergoing a transformation into the riboflavin-leucoform. Simultaneously bilirubin is irreversibly decomposed. Under anaerobic conditions the bilirubin-riboflavin system behaves as an electrochemical equilibrium system, characterized by its redox potential. Leucoform formation was detected by spectrophotometry, polarography and potentiometry. Under aerobic conditions the expected photochemical equilibrium is not established probably owing to the reoxidation of riboflavin-leucoform by oxygen. Of the flavin derivatives present in blood riboflavin, FAD and FMN were tested, riboflavin being the most effective one. This paper summarizes the model studies of biochemical function of flavins, which could be applied to the phototherapy of neonatal jaundice.
Biochemically important reactions of 2-furylethylenes. Reactions with low-molecular thiols
Authors: Šturdík Ernest , Liptaj Tibor , Baláž Štefan , Drobnica Ľudovít
Published: August 2011

As evidenced by spectrophotometry and radiochromatography, derivatives of 2-furylethylene are able to react with thiols in an aqueous medium. The NMR analysis of reaction mixture showed that the site attacked by the thiol is the more electrophilic C(1) atom of the exocyclic double bond of the 2-furylethylenes under study. The ability to react with SH groups is of extraordinary importance particularly in connection with the study of mechanism of biological activity of 2-furylethylenes.
UDP-D-glucose 4-epimerase activity of the tissue culture of white poplars (Populus alba L. var. pyramidalis)
Authors: Bilisics Ladislav , Karácsonyi Štefan , Kubačková Marta
Published: August 2011

The presence of UDP-D-glucose 4-epimerase (EC 5.1.3.2) in the culture tissue of white poplar was evidenced. As found, the partially purified enzyme preparation contained UDP-D-glucose glucosyltransferase, UDP-D-galactose galactosyltransferase and non-specific enzymes able to cleave the uridine-diphosphate saccharides into the appropriate hexose monophosphates. The activity change of UDP-D-glucose 4-epimerase in tissue culture cells during the growth was in accord with changes in D-galactose content in cell walls and indicated the possibility to regulate the formation of polysaccharides containing D-galactose at the level of production of UDP-D-galactose in cells.
Vibrational spectra of ammonium ammine-oxo-diperoxovanadate
Authors: Schwendt Peter , Pisárčik Miloslav
Published: August 2011

Infrared and Raman spectra of solid NH4[VO(O2)2NH3], ND4[VO(O2)2ND3], 14/15NH4[VO(O2)214/15NH3] (about 50% 15N) and Raman spectrum of solution of NH4[VO(O2)2NH3] have been measured. Interpretation of the spectra was complemented by normal coordinate analysis in the approximation of point mass model (NH3). The results have shown that there exists coupling of vibrations of two V(O2) groups, which enables an explanation of differences between spectra of the mono- and diperoxo complexes. The vibrational coupling of VO and OO bonds within one V(O2) group probably causes small sensitivity of wave number of v(O-O) band to changes of d(O-O) bond length.
A CNDO/2 study of reactivity of methylene group in 1-methyl-1,4-dihydronicotinamide
Authors: Krechl Jiří , Kuthan Josef
Published: August 2011

An attempt has been made to use the CNDO/2 method for prediction of the reaction profile and electronic mechanism of elimination of 4-hydrogen atom of 1-methyl-1,4-dihydronicotinamide (I).
Preparation and reactions of methyl 2-bromomethyl-3-(5-nitro-2-furyl)propenoate
Authors: Žvak Vladimír , Kováč Jaroslav , Kríž Miroslav
Published: August 2011

Methyl 2-bromomethyl-3-(5-nitro-2-furyl)propenoate was prepared by nitration of methyl 2-bromomethyl-3-(2-furyl)propenoate with nitric acid and acetic anhydride at -30 °C. 5-Nitrofuran derivatives of a new type were synthesized by nucleophilic substitutions at bromomethyl group.
1,2-Fused derivatives of ergoline
Authors: Beneš Jan , Holubek Jiří
Published: August 2011

2-Formylergoline derivatives I and II were condensed with methyl isonitrilacetate in the presence of a base. Depending on the nature of this base, the main products of the reaction were either derivatives of pyrimido[1,6-a]ergoline, III and IV, or derivatives of 2-formylamino-3-oxo-3H-pyrrolo[1,2-a]ergoline, V and VI.
Liquid-liquid equilibrium in binary glycols-toluene and glycols-xylene systems
Authors: Mandík Lumír , Lešek František
Published: August 2011

Liquid-liquid equilibria were determined in the following binary systems: 1,2-ethandiol/toluene, 1,2-ethandiol/xylene, 1,2-propandiol/toluene, 1,2-propandiol/xylene, 1,4-butandiol/toluene, 1,4-butandiol/xylene, 1,3-butandiol/toluene, 1,3-butandiol/xylene, 1,3-butandiol/p-xylene, 2,2'-dioxydiethanol/toluene, 2,2'-dioxydiethanol/xylene. The solubility of 2,2-dimethyl-1,3-propandiol in benzene, toluene and xylene was also measured. Critical solubility temperatures at atmospheric pressure were determined for systems containing 1,2-propandiol and 1,3-butandiol.
Some electrochemical properties of Raney nickel
Authors: Marholová Olga , Smrček Karel , Ministr Zdeněk , Spitzer Zdeněk
Published: August 2011

The connexion between the functioning of the Raney nickel catalyst in a hydrogen anode and the conditions of its preparation (mode of grinding the alloy, deactivation, and storage of the catalyst) was investigated. The relation between the internal surface area and the activity of the catalyst is discussed.
Theoretical study of annulenes structure [14], [16] and [18] annulenes
Authors: Loos Dušan , Leška Jaroslav
Published: August 2011

The quantum-chemical methods EHT, CNDO/2, MINDO/2 and the method of empirical potentials have been used for calculation of equilibrium geometry of six isomers of [14] annulene, four isomers of [16], and three isomers of [18] annulenes. The bond strengths and degree of delocalization are characterized by the overlap populations and the Wiberg indices. Relative stabilities have been determined by comparison of enthalpies of formation calculated by the MINDO/2 and empirical potential methods. Influence of internal strain of the molecules on their stability lowering is discussed. The degree of aromaticity has been determined by calculation of several aromaticity indexes.
Dipole moments induced in larger molecules. Triphenylmethyl derivatives
Authors: Exner Otto , Iarossi Dario , Vivarelli Piero
Published: August 2011

Dipole moments of triphenylmethyl derivatives I-VI with electron attracting functional groups were measured in benzene solution. Comparison with respective methyl and tert-butyl derivatives revealed the moments induced in the phenyl group which are possibly somewhat greater than those induced in an alkyl group. These moments should be accounted for when determining mesomeric dipole moments of acceptor groups from benzene derivatives; however, a quantitative evaluation is not yet possible.
Electrode kinetics of Eu3+/Eu2+ reaction by cyclic voltammetry
Authors: Radhakrishnan T. P. , Sundaram A. K.
Published: August 2011

The paper is a detailed study of the cyclic voltammetric behaviour of Eu3+ at HMDE in molar solutions of KCl, KBr, KI, KSCN and in 0.1M-EDTA solution with an indigenously built equipment. The computed values of the rate constants at various scan rates show good agreement with those reported by other electrochemical methods. In addition, the results indicate participation of a bridged activated complex in the electron-transfer step, the rate constants showing the trend SCN- > I- > Br- > Cl- usually observed for bridging order of these anions in homogeneous electron-transfer reactions. The results for Eu-EDTA system, however, indicate involvement of an outer sphere activated complex in the electrode reaction.
Isotachophoresis of complex ions
Authors: Gebauer Petr , Boček Petr
Published: August 2011

The present paper quantitatively describes four fundamental types of the migration of complex anions in an isotachophoretic arrangement, observed experimentally, and suggests the possibilities of utilizing the differences in the migration behaviour for analytical separations. Kinetically inert complexes form stable zones under isotachophoretic conditions and their migration behaviour does not differ from isotachophoresis of simple ions. Kinetically labile complexes are in the dissociation equilibrium with the free metal cations and the free ligand and their progressive decomposition occurs in the course of the migration, i.e., the zone of the complex is not migrationally stable. By selecting operating conditions properly, in the first place the pH of the leading electrolyte, the migration stability of the zones of complexes can be influenced selectively in such a way that the decomposition of one of the complexes will be suppressed to a negligible extent while another complex will decompose totally in the course of the migration and will provide an equivalent zone of the free ligand. Various migration behaviour of the complexes can be applied in order that both required analytical separation may be obtained and the isotachophoregram may be evaluated quantitatively.
Pyrolysis of unsubstituted bicyclic hydrocarbons and gas oil
Authors: Bajus Martin , Baxa Jozef
Published: August 2011

Pyrolysis of tetraline, decaline, 1,1'-bicyclohexane, cyclohexylbenzene and gas oil was studied in stainless steel and quartz flow tubular reactors at 780 and 800 °C, residence time 0.08 to 0.5 s and at the mass ratio of steam to the raw material changing from 0.5 to 1.5. The effect of reaction temperature, the mass ratio of steam to the raw material, reactor material and of the added elemental sulphur on the yields of individual reaction products is reported. Of bicyclic hydrocarbons, condensed hydrocarbons are more stable than those with noncondensed rings, cyclanoaromates being more stable than bicyclanes. Pyrolysis of gas oil in the stainless steel reactor yields greater amounts of ethylene, propylene, butadiene and smaller amounts of methane and ethane, compared to the pyrolysis carried out under identical conditions in the quartz reactor. Elemental sulphur increases the conversion of gas oil into gaseous pyrolysis products.
The syntheses of juvenogen derivatives of 2-[4-(3-ethoxy-3-methyl-1-butoxy)benzyl]-1-cyclohexanol
Authors: Wimmer Zdeněk , Romaňuk Miroslav
Published: August 2011

The syntheses of several juvenogen derivatives of both isomeric racemic 2-[4-(3-ethoxy-3-methyl-1-butoxy)benzyl]-1-cyclohexanols were described, in connection with the investigation of integrated protection of cultural plants against insect pests.
Simultaneous effect of axial dispersion and adsorption kinetics on a form of the breakthrough curve of an adsorber
Authors: Kočiřík Milan , Hálová Jaroslava
Published: August 2011

The model of an adsorption bed is described in which the effect of axial dispersion and overall adsorption kinetics on a shape of the breakthrough curve is considered simultaneously. Separation of the effects of convection and axial dispersion from the effect of overall kinetics was achieved applying the method of statistical moments. On the basis of relations derived for the moments, several further characteristics of the breakthrough curves were expressed.
Hydrodynamic characteristics of gas-liquid beds in contactors with ejector-type gas distributors
Authors: Zahradník Jindřich , Kaštánek František , Kratochvíl Jan , Rylek Milan
Published: August 2011

The effect of ejector-nozzle geometry on gas holdup and on the rate of interfacial mass transfer characterized by values of kLa was studied in a tower reactor with ejector-type gas distributor. It has been established that both gas holdup and kLa values are, in contactors of this type, unambiguously determined by the rate of energy dissipation in the place of gas-liquid dispersion formation i.e. in the ejector. No effect of nozzle type and geometry was observed on the character of dependences of gas holdup and kLa on the energy dissipation rate and consequently on the values of coefficients of empirical exponential-type relations used for experimental data correlation.
Kinetic investigation of cyclization of 1-acetyl-1'-(X-cinnamoyl)ferrocenes
Authors: Toma Štefan , Gáplovský Anton , Federič Jozef
Published: August 2011

Ten substituted 1-acetyl-1'-(X-cinnamoyl)ferrocenes were prepared and the kinetics of their cyclization to 3-aryl[5]ferrocenophane-1,5-diones was investigated. Cyclizations are the first order reactions with respect to the starting compounds ΔH##f ~ 85 kJ mol-1 and -ΔS##f ~ 40 to 60 J mol-1. The log k well correlated with σ constants, and ρ (0.83) is virtually temperature independent in the studied 35-55 °C interval.
Preparation of 5-(β-D-ribofuranosyl)pyrazole-3-carboxamide
Authors: Vaněk Tomáš , Gut Jiří
Published: August 2011

Synthesis of the pyrazole analogue of ribavirin (I), 5-(β-D-ribofuranosyl)pyrazole-3-carboxamide (II), is described. The compound II exhibits low virostatic activity.
Application of some reagents used in organic functional group analysis for identification of amines, alcohols, aldehydes and ketones to elimination of these substances from organic mixtures in reaction gas chromatography
Authors: Komárek Karel , Nováková Jarmila , Ventura Karel , Churáček Jaroslav
Published: August 2011

A number of reagents have been tested for elimination of lower aliphatic amines and alcohols from mixtures of organic compounds, viz. 4-toluenesulphonyl chloride, 3,5-dinitrobenzoyl chloride, N,N-dimethyl-4'-aminoazobenzene-4-carboxylic acid chloride, 3-nitrophthalic anhydride, phthalic anhydride, N,N-dimethyl-4-aminobenzaldehyde and 1-naphthyl isocyanate. Aldehydes and ketones have been eliminated with 2,4-dinitrophenylhydrazine or 4-nitrophenylhydrazine in the presence of phosphoric acid. The reaction column was placed in the thermostat along with the chromatographic column. The reagents were introduced on Celite 545 or Chromaton N.
Simple theoretical models for elimination reactions on polar catalysts; The reactivity of halogeno-, hydroxy-, amino- and mercaptopropane
Authors: Sedláček Jiří
Published: August 2011

CNDO/2 calculations have been made for simple models of the adsorption of (CH3)2CHZ molecules (Z = Cl, OH, NH2, and SH) on the surface of polar catalysts. The results of these calculations and their interpretation by the method of configuration analysis in terms of uniformly localized molecular orbitals made it possible to explain satisfactorily a series of experimental facts. The mechanism and stereoselectivity of the reaction as well as reactivity trends for the series of the molecules studied are discussed.
A tensometric method to determine the hold-up of liquid in packed bed apparatures
Authors: Jiřičný Vladimír , Staněk Vladimír , Šmíd Jiří , Jelínek Vladimír
Published: August 2011

Results have been presented in the paper of the tests and calibration of a tensometric scale developed for weighing packed bed columns under operating conditions. The results have shown the tensometric method to be suitable weighing packed bed columns under the two-phase flow of gas and liquid in the dynamic state. Experimental results have been presented of the steady state liquid hold-up and gas pressure drop obtained by the developed tensometric method in an experimental column 190 mm in diameter. The experimental data have been compared with those of other authors obtained by different experimental techniques.
Fast scan differential pulse polarographic determination of cyanide
Authors: Stará Věra , Kopanica Miloslav
Published: August 2011

The measurement of the catalytic current, caused by the interaction between cyanide and nickel(II)-ethanolamine complex enables the determination with the detection limit 0.4 μg l-1 with the relative mean deviation 0.90%. Direct fast pulse polarographic determination, based on the measurement of the anodic current has the limit 40 μg l-1 and the relative mean deviation 0.93%.
Approximation of the adsorption heats of hydrogen on transition metals by means of an empirical model
Authors: Štrouf Oldřich , Fusek Jiří , Kuchynka Karel
Published: August 2011

The adsorption heats of hydrogen on transition metals were approximated using a first order polynomial containing variables of basic physical importance, which were determined recently by means of the empirical method of pattern recognition: the heat of fusion, heat of vaporization, Pauling electronegativity, molar thermal conductivity, first and second ionization energies, electrical conductivity, Debye temperature and atomic volume of the metal. The agreement with experimental values is closer than that obtained with the Pauling relation. Values of adsorption heats are predicted for seven transition metals.
Drop size distributions by power functions of breakage and coalescence
Authors: Sovová Helena
Published: August 2011

The frequencies of drop breakage and coalescence in a batch mixer are described by power functions of drop sizes. The shape of a steady state drop size distribution corresponding to the power functions is correlated with their exponents. The use of this correlation for direct determination of linear combination of power functions exponents from an experimental drop size distribution is demonstrated.
Oxidation of galactose by manganese(III) sulphate
Authors: Barek Jiří , Berka Antonín , Pokorná-Hladíková Alena
Published: August 2011

Galactose was found to be oxidized by manganese(III) sulphate according to the equation

OHC-(CHOH)4-CH2OH + 10 Mn3+ + 5 H2O → 5 HCOOH + CH2O + 10 Mn2+ + 10 H+.

The kinetics of the reaction was studied and its mechanism suggested. A procedure was worked out for indirect titrimetric determination of galactose based on its oxidation with excess manganese(III) sulphate and potentiometric retitration of the unreacted reagent with iron(II) sulphate.
Spectroscopic study of the solute effect on the structure of liquid water
Authors: Holba Vladislav
Published: August 2011

The effect of ten electrolytes and eight nonelectrolytes on the structure of liquid water in a H2O-D2O mixture was studied by near infrared spectroscopy. The results are interpreted in terms of the disturbing or promoting effect of solute on the cluster structure of water. The standard enthalpies of the hydrogen bond formation and the structure temperatures of the solutions were determined based on the temperature dependence of the absorbances.
Benzyloxyarylaliphatic acids: Synthesis and quantitative relations between structure and antiinflammatory activity
Authors: Kuchař Miroslav , Rejholec Václav , Brunová Bohumila , Grimová Jaroslava , Matoušová Oluše , Němeček Oldřich , Čepeláková Hana
Published: August 2011

The paper describes synthesis of substituted benzyloxyarylaliphatic acids, I-V, and their efficacy in stabilization the erythrocyte membrane against hypotonic haemolysis and their antiinflammatory effect in inhibition of the kaolin oedema. The quantitative relations between these efficacies and the physico-chemical and structural parameters of the acids have been analysed. The two activities depend on the overall lipophilicity and acidity of the acids. In the investigated range of lipophilicity the dependence of the antiinflammatory effect on lipophilicity had a parabolic course, whereas in stabilization of the erythrocyte membrane this dependence was linear. In either case the efficacy was suppressed by extending the connecting chain between the carboxyl and the aromatic ring. Regression analysis suggests that in the group of benzyloxyarylaliphatic acids it is not possible to prepare compounds more effective than 3-chloro-4-benzyloxyphenylacetic acid (benzofenac, Ia) and its 2-methyl analogue IIa.
2-Substituted derivatives of 5-(4-oxo-3,4-dihydro-5-pyrimidinyl)pentanoic acid
Authors: Kotva Rudolf , Křepelka Jiří , Vachek Jaroslav
Published: August 2011

Condensation of trialkyl esters of 6-substituted 2-carboxy-1,7-heptanedioic acids XII-XVII with urea or thiourea and subsequent saponification gave 2-substituted 5-(2,6-dihydroxy-4-oxo-3,4-dihydro-5-pyrimidinyl)pentanoic acids II-VI or 5-(2-mercapto-6-hydroxy-4-oxo-3,4-dihydro-6-pyrimidinyl)pentanoic acids VII-XI, respectively. Compounds II, VII and X had a weak antineoplastic effect in animals with experimental transplantable tumours.
Synthesis and properties of oxytocin analogues with high and selective natriuretic activity
Authors: Lebl Michal , Hrbas Pavel , Škopková Jana , Slaninová Jiřina , Machová Alena , Barth Tomislav , Jošt Karel
Published: August 2011

Deamino-6-carba-oxytocin analogues with modified aromatic amino acid in the position 2 were prepared by stepwise peptide synthesis in solution and cyclization in the last step. Some of the prepared analogues exhibit high and/or specific natriuretic activity. Structural requirements for this type biologic activity are discussed.
Electronic absorption, fluorescence and polarisation spectra of 1- and 2-amino-9,10-anthraquinones and their interpretation by the method of configuration analysis
Authors: Nepraš Miloš , Fabian Jürgen , Titz Miloš , Gaš Bohuslav
Published: August 2011

Absorption frequency-dependent polarisation spectra of fluorescence (APF) and dichroism on oriented polyvinyl alcohol sheets have been measured and used as a basis for interpretation of absorption spectra of 1- and 2-amino-9,10-anthraquinones in the region 250-600 nm. Character of the excited states was determined by the method of configuration analysis (PPP-CA).
Electronic absorption, fluorescence and polarisation spectra of α,α'-diamino-9,10-anthraquinones and their interpretation by the method of configuration analysis
Authors: Nepraš Miloš , Gaš Bohuslav , Fabian Jürgen , Titz Miloš
Published: August 2011

On the basis of measurement of absorption frequency-dependent polarisation spectra of fluorescence (APF) and dichroism on oriented polyvinyl alcohol sheets interpretation has been carried out of absorption spectra of α,α'-diamino-9,10-anthraquinones in the wavelength range 250 to 600 nm. Character of the excited states has been determined by the method of configuration analysis (PPP-CA).
Electronic absorption, fluorescence and polarisation spectra of α,β-diamino-9,10-anthraquinones and their interpretation by the method of configuration analysis
Authors: Nepraš Miloš , Titz Miloš , Fabian Jürgen , Gaš Bohuslav
Published: August 2011

On the basis of measurement of absorption frequency-dependent polarisation spectra of fluorescence (APF) and dichroism on oriented polyvinyl alcohol sheets, interpretation has been carried out of absorption spectra of α,β-diamino-9,10-anthraquinones in the wavelength range 250 to 600 nm. Character of the excited states has been investigated by the method of configuration analysis (PPP-CA).
The crystal and molecular structure of aqua-bis(ethylenediamine)cupric-tris(cyano)-selenocyanatodicuprate
Authors: Vrábel Viktor , Lokaj Jan , Garaj Ján , Pavelčík František
Published: August 2011

The crystal structure of [Cu(H2O)(en)2][Cu2(CN)3(SeCN)] was solved by single crystal X-ray structural analysis in the triclinic system with a space group of P1 and in the monoclinic system with a space group of C2. In the triclinic system the unit cell has dimensions of a = 0.8445(3), b = 0.7903(3), c = 0.8444(3) nm, α = 119.58(2), β = 118.59(2) and γ = 93.63(3)° and, in the monoclinic system, a = 1.3331(4), b = 0.8670(2), c = 0.8267(3), β = 122.60(2)°. The structure was refined by the least squares method to final value of R = 5.5% in the triclinic system and R = 7.8% in the monoclinic system. The coordination sphere around the Cu(II) atom is square pyramidal, formed of two ethylenediamine molecules and one water molecule. The Cu(I) atoms are tetrahedrally coordinated by bridging SeCN and CN ligands to form infinite three-dimensional chains. The SeCN group is bonded to the Cu(I) atoms through the Se atom at distances of 0.2731(3) and 0.2745(3) nm.
Analysis of observability of model parameters for physical absorption of poorly soluble gases in packed beds
Authors: Moravec Pavel , Staněk Vladimír
Published: August 2011

Expressions have been derived for four possible transfer functions of a model of physical absorption of a poorly soluble gas in a packed bed column. The model has been based on axially dispersed flow of gas, plug flow of liquid through stagnant and dynamic regions and interfacial transport of the absorbed component. The obtained transfer functions have been transformed into the frequency domain and their amplitude ratios and phase lags have been evaluated using the complex arithmetic feature of the EC-1033 computer. Two of the derived transfer functions have been found directly applicable for processing of experimental data. Of the remaining two one is useable with the limitations to absorption on a shallow layer of packing, the other is entirely worthless for the case of poorly soluble gases.
Mass spectra of 4,4-dimethyl-A-homo-4a,6-cholestadien-3-ols, 4,4-dimethyl-A-homo-5-cholestene-3,4a-diols and their derivatives
Authors: Trka Antonín , Velgová Helena
Published: August 2011

Partial electron impact induced mass spectra are given of 3α-hydroxy-, 3β-hydroxy-, 3β-methoxy-, 3α-acetoxy- and 3β-acetoxy-4,4-dimethyl-A-homo-4a,6-cholestadienes, 3α,5α-epoxy-4,4-dimethyl-A-homo-5-cholestane, isomeric 4,4-dimethyl-A-homo-5-cholestene-3α(β),4aα(β)-diols, their 3-acetoxy derivatives and 3-methyl ethers. The fragmentation of the molecular ions of these substances involves the usual elimination of substituents (in the form of H2O, CH3OH, CH3COOH, CH2CO), but the most abundant and characteristic ions are products of the contraction of ring A (to a six- or five-membered one), accompanied by expulsion of a fragment containing the carbon atom C(4) with both methyls.
Preparation of enantiomeric and racemic 2,3,4,5-tetrahydroxypentyl derivatives of adenine, cytosine and uracil
Authors: Holý Antonín
Published: August 2011

1-(Adenin-9-yl)-1-deoxy-DL-ribitol (III), -D-arabitol (IXa), -L-arabitol (XIVa), -DL-xylitol (XXIVa), 1-(cytosin-L-yl)-1-deoxy-D-arabitol (IXb), -L-arabitol (XIVb), 1-(uracil-1-yl)-1-deoxy-D-arabitol (IXc), -L-arabitol (XIVc) and -DL-xylitol (XXIVb) were prepared by reaction of 1-O-p-toluenesulfonyl-2,3:4,5-di-O-isopropylidenealditols Ib, VIIb, XIIb and XXIIb with sodium salts of adenine, N4-benzoylcytosine or 4-methoxy-2-pyrimidone followed by removal of the protecting groups. Condensation of the mentioned sodium salts with methyl 5-O-p-toluenesulfonyl-2,3-O-isopropylidene-β-D-ribofuranoside (IV) with subsequent acid hydrolysis and reduction with sodium borohydride afforded 1-(adenin-9-yl)-1-deoxy-L-ribitol (VIa) and 1-(cytosin-1-yl)-1-deoxy-L-ribitol (VIb). 1-(Adenin-9-yl)-1-deoxy-L-lyxitol (XVII), -L-lyxitol (XVIII) and -2-O-methyl-D-lyxitol (XXI) were prepared analogously. Acid hydrolysis of 5-(adenin-9-yl)-5-deoxy-4-O-benzyl-1,2-O-isopropylidene-α-D-xylofuranose (XXVa), followed by reduction with sodium borohydride and catalytic hydrogenation, gave 1-(adenin-9-yl)-1-deoxy-L-xylitol (XXVIb).
Dearomatization of a jet fuel fraction on a platinum catalyst
Authors: Múčka Viliam , Ostrihoňová Alica , Kopernický Ivan , Mikula Oldřich
Published: August 2011

Some physical and physico-chemical properties of a platinum support catalyst were determined and its application to the dearomatization of a jet fuel fraction was studied. The dearomatization proceeds more readily at lower temperatures, at which, however, the catalyst is more sensitive to poisons. A factorial experiment was designed to determine the optimum conditions for the dearomatization. A virtually complete dearomatization using the spatial flow rate 2 h-1 was achieved at temperatures 245-295 °C and partial pressures of hydrogen 1.5-4 MPa.
8α-Hydroxybalchanin - A new sesquiterpenic lactone from Leucanthemella serotina (L.) TZVEL.
Authors: Holub Miroslav , Samek Zdeněk , Buděšínský Miloš , Šaman David , Błoszyk Ełżbieta , Drożdż Bohdan
Published: August 2011

For the sesquiterpenic lactone isolated from Leucanthemella serotina (L.) TZVEL., called 8α-hydroxybalchanin, the structure I, including relative and absolute configuration, was derived on the basis of IR, CD and mass spectra and mainly 1H NMR spectroscopy.
Reaction of 2,3-dihydro-1,3-6H-oxazine-2,6-dione with aliphatic amines and amino acids
Authors: Farkaš Jiří , Hapala Jaroslav , Jindrová Olga , Škoda Jan
Published: August 2011

Reaction of 2,3-dihydro-1,3-6H-oxazine-2,6-dione (I) with amines in aqueous medium leads predominantly to N-substituted amides of (Z)-3-carboxylamino-2-propenoic acid. Isomeric 3-(N'-alkylureido)-2-propenoic acids are formed as by-products in the reaction of compound I with ammonia or methylamine; tert-butylamine affords ureido derivative as the sole reaction product. Secondary amines react with compound I substantially more rapidly than primary amines. In both cases the branching on the α-carbon decreases the reactivity distinctly while the branching on the β-carbon does not have a significant effect on the rate of aminolysis. The results of kinetic measurements of the reaction of compound I with amino acids are discussed n connection with the possible interaction of compound I with enzymes.
Analysis of frequency responses of model flows of liquid in trickle beds
Authors: Staněk Vladimír , Čársky Milan
Published: August 2011

Frequency responses have been derived for four mathematical models of the trickle flow in a packed bed column. The models contain gradually one to four parameters. Asymptotic expressions have been also obtained for the frequency responses under large values of the Peclet number. A possibility has been tested of using the complex arithmetic feature of a computer to evaluate numerically the model responses and to separate the real and the imaginary part of the response. Analysis has shown that all four models can be discriminated and their parameters are observable in the complex plane. This approach thus appears plausible for processing real experimental data as well as for the discrimination between various models.
Potential psychotropic and antihistamine agents: 1- and 3-alkyl-9-(3-dimethylaminopropylidene)-thioxanthenes and 3-alkyl-11-piperazino-10,11-dihydrodibenzo[b,f]thiepins
Authors: Protiva Miroslav , Šedivý Zdeněk , Holubek Jiří , Svátek Emil , Metyšová Jiřina , Bartošová Marie
Published: August 2011

Reactions of 3-methylthiophenol and 3-ethylthiophenol with 2-iodobenzoic acid and (2-iodophenyl)acetic acid in the presence of potassium hydroxide and copper gave the acids IVab and Xab. The acids IVab afforded by cyclization with sulfuric acid mixtures of 1- and 3-alkylthioxanthones (Va + VIa, Vb + VIb) which were separated by crystallization or chromatography and the individual compounds were identified by spectra. The slightly prevailing 3-alkyl derivatives Vab were reacted with 3-dimethylaminopropylmagnesium chloride to give the tertiary alcohols VIIab which were transformed by the acid catalyzed dehydration to the title compounds Iab. 1-Ethylthioxanthone (VIb) afforded similarly via the tertiary alcohol VIII the title compound IX. The acids Xab were cyclized with polyphosphoric acid unequivocally to the ketones XIab which were converted via the alcohols XIIab to the chloro derivatives XIIIab. Substitution reactions with 1-methylpiperazine and 1-(2-hydroxyethyl)piperazine led to the title compounds IIab and IIIb. The compounds prepared (I-III) have antihistamine activity and are more or less central depressant. Compounds Ib, IIb and IIIb revealed a clear cataleptic activity and compound Ib showed also antireserpine activity. Compound IX is centrally depressant only in high doses but it has anticonvulsant effects and a significant antitussive effect.
Liquid-vapour equilibrium and heats of mixing in the 1-propanol-acetonitrile system
Authors: Dohnal Vladimír , Veselý František , Vinš Jaroslav
Published: August 2011

Vapour-liquid equilibrium and heats of mixing were measured in the 1-propanol-acetonitrile system. The vapour-liquid equilibrium data measurements were carried out under isobaric conditions at the pressures 37.54, 56.44 and 86.05 kPa and isothermally at temperatures of 333.25 and 351.22 K. The heats of mixing were measured at temperatures of 298.15, 308.15 and 318.15 K. The individual vapour-liquid equilibrium data sets were correlated by various two-parameter equations, the data on heats of mixing by a Redlich-Kister polynomial. The extensive data obtained for both excess functions, covering the temperature range of 60 K, were correlated successfully by the Wilson equation with the energy parameters dependent quadratically on temperature.
Electrosyntheses of 3-acetyl- and 3-methoxycarbonyl-2,5-dimethoxy-2,5-dihydrofuranes
Authors: Stibor Ivan , Šrogl Jan , Janda Miroslav , Piričová Naděžda , Vlažný Karel
Published: August 2011

Electrochemical methoxylation of furane derivatives has been used to synthetize 3-acetyl-2,5-dimethoxy-2,5-dihydrofurane (I) and methyl 2,5-dimethoxy-2,5-dihydro-3-furoate (II). Addition reaction of methanol with the ester II gave rise to methyl 2,4,5-trimethoxytetrahydro-3-furoates IVa-IVc, which were separated and identified by their 1H NMR spectra. Using the same method, we identified isomeric 3-hydroxymethyl-2,4,5-trimethoxytetrahydrofuranes Va-Vc, formed by reduction of the ester II with a hydride, and methyl 2,5-dimethoxytetrahydro-3-furoates VIa-VIc, formed by hydrogenation of II on Pd.
Synthesis and reactions of substituted benzofuro[3,2-b]pyrrole derivatives
Authors: Krutošíková Alžbeta , Kováč Jaroslav , Dandárová Miloslava , Bobálová Mária
Published: August 2011

This paper deals with the preparation of ethyl benzofuro[3,2-b]pyrrole-2-carboxylate, its hydrolysis, N-alkylation, and reduction. Also the synthesis of new heterocyclic systems, benzofuro[3,2-b]pyrrole and 2H-dihydrobenzofuro[2',3':4,5]pyrrolo[1,2-d]-1,2,4-triazin-1-one, is described. The structure of 14 new substances was corroborated by IR, UV, 1H NMR, 13C NMR and electron impact mass spectra.
Effects of structure and concentration on ionic association in alkali alkoxide-conjugate acid solutions: Reluctance to formation of ion-pair aggregates
Authors: Pechanec Václav , Kocián Oldřich , Závada Jiří
Published: August 2011

Degrees of ionic association, napp, were ebulliometrically determined in 0.06-0.6 molal region for eighteen RO(-)M(+)-ROH base-conjugate acid combinations (R = H, CH3, C2H5, n-C3H7, i-C3H7, t-C4H9; M(+) = Li(+), Na(+), K(+)) and found to range between the extremes 0.5 and 0.4. Presence of ion-pair aggregates (napp > 1) was established only in two of the examined combinations (i-C3H7OLi-i-C3H7OH and t-C4H9OLi-t-C4H9OH).
Binding of lead cations to oligogalacturonic acids
Authors: Kohn Rudolf
Published: August 2011

The activity of Pb2+ ions in solutions of lead oligogalacturonates of polymerization degree DP 1 to 5 (starting concentration of the investigated solutions 3.00 mmol (COOPb0.5) l-1, the ionic strenght of the solution I = 0.01 mol l-1, electrolyte KNO3, was determined by lead specific ion electrodes. The activity aPb2+ is independent on the kind of anion in very diluted solutions of lead perchlorate and nitrate. Ions of lead become bound quite firmly even to the monomeric D-galacturonic acid (association degree of Pb2+ ions to carboxyl groups of uronic acid β = 0.43). The increase of polymerization degree is associated with a strong decrease of the lead oligogalacturonate solubilities on one hand, and increase of the bond strenght of the Pb2+ ions to these oligomers on the other. The association degree of Pb2+ ions to carboxyl groups of the pentamer (β = 0.96) almost reaches the value found for the polymeric chain of pectate molecule (D-galacturonan); here, the stoichiometric binding of Pb2+ to two carboxyl groups takes place with a great deal of probability. Lead has been found to bind highly preferentially to oligogalacturonates even in the presence of calcium ions. Results presented in this paper help to clear the mechanism of elimination of lead from the human body through pectin and its oligomeric fragments.
Preparation of 5'-O-phosphonylmethyl analogues of nucleoside-5'-phosphates, 5'-diphosphates and 5'-triphosphates
Authors: Holý Antonín , Rosenberg Ivan
Published: August 2011

Reaction of a trialkyl phosphite (VI) or sodium salt of dialkyl phosphite (V) with bromomethyl acetate afforded dialkyl acetoxymethanephosphonates VII which were alcoholyzed to dialkyl hydroxymethanephosphonates VIII. Tosylation of the compounds VIII gave dialkyl p-toluenesulfonyloxymethanephosphonates IX which on reaction with 2',3'-O-isopropylideneribonucleosides (I), 2',3'-O-ethoxymethyleneribonucleosides (XI) or 3'-O-tetrahydropyranyl-2'-deoxyribonucleosides in the presence of sodium hydride, followed by acid hydrolysis, were converted into alkyl esters of 5'-O-phosphonylmethylnucleosides XII. Treatment of compounds XII with trimethylsilyl iodide led to 5'-O-phosphonylmethylnucleosides II and XIV. The ribo derivatives II were also obtained in low yields by reaction of compounds I with sodium chloromethanephosphonate in the presence of sodium hydride. Compound II reacted with morpholine in the presence of N,N'-dicyclohexylcarbodiimide to give morpholides XV which on treatment with phosphate afforded 5'-O-phosphorylphosphonylmethylribonucleosides XVI. Analogously, 5'-O-diphosphorylphosphonylmethylribonucleosides XVII were obtained from the derivatives XV by reaction with diphosphate. The compounds II are resistant towards E. coli alkaline phosphomonoesterase and snake venom and bull semen 5'-nucleotidase. E. coli alkaline phosphomonoesterase degrades the compounds XVI and XVII to compounds II and inorganic phosphate.
Inhibition by CTP and UTP analogues of uridine kinase from mouse leukemic cells
Authors: Veselý Jiří , Rosenberg Ivan , Holý Antonín
Published: August 2011

The new phosphonate analogues of CTP and UTP (CTPc and UTPc) inhibit the phosphorylation of uridine catalysed by uridine kinase in the presence of ATP and Mg2+-ions. The inhibition is competitive with respect to phosphate donor, and non-competitive with respect to phosphate acceptor. With respect to uridine the Ki constants for CTPc and UTPc are 7.5 . 10-5 mol l-1 and 1.0 . 10-4 mol l-1, respectively. With respect to ATP the Ki value for CTPc (3.6 . 10-6 mol l-1) is 3x lower than that for CTP. The novel analogues could be useful for further study of uridine kinase.
The social difficulties of cancer patients of South Asian Indian and Pakistani origin: a cross-sectional questionnaire and interview study
Authors: Dharni Nimarta , Hanif Naheed , Bradley Chris , Velikova Galina , Stark Dan , Wright Penny
Published: August 2011

Objectives

To evaluate, in a sample of patients of South Asian (SA) origin, the acceptability of introducing assessment of social difficulties in everyday practice, examine the range and severity of reported social difficulties and inquire about their management.

Design

A cross-sectional study in which participants completed the Social Difficulties Inventory (SDI-21) in English, Urdu, Punjabi or Hindi followed by a semi-structured interview.

Participants

Participants comprised 26 men and 29 women of SA origin ranging between 18 and 80 years of age. The commonest primary languages were Urdu (n=17) and Punjabi (n=17). English was the primary language of three participants. A range of cancer diagnoses and stages of disease were represented.

Setting

Patients were recruited from outpatient haematology and oncology clinics in Bradford, Airedale and Leeds hospitals.

Results

SA cancer patients welcomed routine assessment of social difficulties as part of their cancer care. They reported higher levels of social distress than found in earlier studies of white British patients. The majority managed their social difficulties themselves with little discussion with the clinical team, although, at times, this would have been welcomed. SA patients lacked information and were unaware of the support available to them, especially when language was a barrier.

Conclusions

Introduction of routine assessment of social difficulties into cancer care will require not only relevant and accessible screening tools such as the SDI-21, but also staff trained to respond to the difficulties disclosed, with knowledge of information sources and supportive care services when patients request these.
Death and legal fictions: Table 1
Authors: Shah Seema K , Truog Robert D , Miller Franklin G
Published: August 2011

Advances in life-saving technologies in the past few decades have challenged our traditional understandings of death. Traditionally, death was understood to occur when a person stops breathing, their heart stops beating and they are cold to the touch. Today, physicians determine death by relying on a diagnosis of ‘total brain failure’ or by waiting a short while after circulation stops. Evidence has emerged, however, that the conceptual bases for these approaches to determining death are fundamentally flawed and depart substantially from the established biological conception of death. We argue that the current approach to determining death consists of two different types of unacknowledged legal fictions. These legal fictions were developed for practices that are largely ethically legitimate but need to be reconciled with the law. The considerable debate over the determination of death in the medical and scientific literature has not informed the public that vital organs are being procured from still-living donors and it seems unlikely that this information can remain hidden for long. Given the instability of the status quo and the difficulty of making the substantial legal changes required by complete transparency, we argue for a second-best policy solution: acknowledging the legal fictions involved in determining death to move in the direction of greater transparency. This may someday result in more substantial legal change to directly confront the challenges raised by life-sustaining and life-preserving technologies without the need for fictions.
Plasma dioxin levels and cause-specific mortality in an occupational cohort of workers exposed to chlorophenoxy herbicides, chlorophenols and contaminants
Authors: Boers Daisy , Portengen Lützen , Turner Wayman E , Bueno-de-Mesquita H Bas , Heederik Dick , Vermeulen Roel
Published: August 2011

Background

We recently reported increased risks for all cancers and urinary cancers in workers exposed to chlorophenoxy herbicides using data from the Dutch herbicide cohort study. These risks could not be linked to the qualitative exposure proxies available. Here, we re-investigate exposure–response relationships using a (semi)quantitative measure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure.

Methods

Plasma TCDD levels of 187 workers were used to develop a predictive model for TCDD exposure. Cox proportional hazards model was used to investigate associations between time-varying TCDD exposure and cause-specific mortality. Sensitivity analyses were performed to assess the impact of key assumptions in exposure assessment.

Results

Predicted TCDD levels were associated with mortality from all causes (HR 1.08; 95% CI 1.03 to 1.13), ischaemic heart disease (IHD; HR 1.19; 95% CI 1.08 to 1.32) and non-Hodgkin's lymphoma (NHL; HR 1.36; 95% CI 1.06 to 1.74). No relationships were found between TCDD exposure and mortality from all cancers, respiratory or urinary cancers, which were previously linked to qualitative proxies of TCDD exposure in this cohort. Sensitivity analyses showed that results were relatively robust to slight changes in exposure estimation.

Conclusions

Modelled TCDD exposure does not explain the previously reported increased risks for cancer mortality in this cohort except for a possible association with NHL. A small increase in ischaemic heart disease was observed, however we cannot exclude that this finding was due to residual confounding. Although risk estimates for some of the rarer outcomes were still rather imprecise, we do not expect more precise estimates from longer follow-up of this cohort due to the long time-span since last exposure to TCDD.