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  • 1
    Electronic Resource
    Electronic Resource
    Mathematical model for the optimization of the reaction between 2,3-bis(m-tolyl)quinolizinium bromide and piperidine using a factorial design (1992)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 6 (1992), S. 1-10 
    Details
    ISSN: 0886-9383
    Keywords: Derivatization reaction ; Factorial design ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A number of nucleophiles have been successfully identified and quantified using the Kröhnke reaction with 2,3-diphenyl derivatives of quinolizinium salts. Optimization of the reaction conditions by means of a mathematical model involving analysis of the response surface has led to a better understanding of the factors exerting an influence on the above reaction.The parameters chosen were temperature, reaction time, base concentration, water concentration and nucleophile concentration. The reaction was developed in polar aprotic solvents (acetone, acetonitrile). To facilitate the nucleophilic attack, the presence of an organic base (triethylamine) was necessary, although concentrations in excess of 0·15M did not alter the development of the reaction. Since pharmaceutical solutions are often aqueous, the influence of water on the reaction was studied. Low water volumes have no significant influence on the opening of the quinolizinium ring by the nucleophilic reagent. However, when the water proportion exceeded that of the organic solvent, the fluorescence intensity was lower than expected. Development of the fluorescent reaction product was first detected 5 min after the reaction started. The fluorescence intensity reached its optimum value after 138 min.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180060102
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of stereoregular polygluconamides from D-glucose and D-glucosamine (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 299-305 
    Details
    ISSN: 0887-624X
    Keywords: polygluconamides ; stereoregular polyamides ; stereoregular nylons ; chiral polyamides ; chiral nylons ; aminoaldonic acids ; sugar polyamides ; carbohydrate monomers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two stereoregular polygluconamides, one (3) of polypeptide-type and the other (16) being a polycaproamide containing four stereocenters in the main chain of the repeating unit, have been prepared from D-glucosamine and D-glucose, respectively. The new polyamides were characterized by elemental analysis, and IR, 1H- and 13C-NMR spectroscopies. The molecular weights for 3 and 16 were estimated as 25,000 and 67,000, respectively, on the basis of viscosimetric measurements. Both polyamides display high optical activity; they are highly hydrophilic and readily soluble in water as well as in a variety of organic solvents including chloroform. Polyamide 16 is highly crystalline and yields resistant films with spherulitic texture. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330211
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  • 3
    Electronic Resource
    Electronic Resource
    Chiroptical properties, structure, and absolute configuration of heterosubstituted 2(5H)-furanones (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 537-544 
    Details
    ISSN: 0899-0042
    Keywords: Circular dichroism ; helicity rule ; X-ray structure determination ; ultraviolet spectra ; n - π* and π - π* bands ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiroptical properties of a series of 3 and/or 4-heterosubstituted 2(5H)-furanones were investigated with respect to correlation with absolute configuration. The n - π* and π - π* Cotton effects have been assigned on the basis of comparison with the UV spectra in solvents of varying polarity. It is demonstrated that the n - π* transition in 4-amino substituted 2(5H)-furanones appears at shorter wavelength with respect to the π - π* transition. With the exception of 4-pyrrolidino and 4-benzylamino substituted 2(5H)-furanones, other heterosubstituted 2(5H)-furanones follow the butenolide configurational rule (Gawronski et al. J. Org. Chem. 61:1513-1515, 1996). Absolute configuration of 2(5H)-furanone derivatives can also be assigned according to the sign of the Cotton effect (of unknown origin) at 200-230 nm. The structure of four representative sulfur and nitrogen substituted 2(5H)-furanones has been analyzed by X-ray diffraction. The results indicate planarity of the furanone ring and extended conjugation in 4-amino substituted 2(5H)-furanones. Chirality 9:537-544, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    A simplified method for deuterium/hydrogen isotope ratio measurements on water samples of biological origin (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 383-387 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Equilibration of hydrogen gas with the water in a variety of biological sample materials was carried out in Vacutainers using platinum-on-alumina catalyst physically isolated from the liquid water. The equilibration takes 3 days at room temperature - much slower than with catalysts which float on the water surface - but this reduces the short-term temperature sensitivity of the procedure, and the inexpensive materials used allow convenient disposal of biologically contaminated samples after analysis. The slow equilibration also allows time for complete exchange with water contained in a complex sample matrix such as plant stems or soil without the need for prior isolation of the water sample. The method has particular application in studies of human total body water where repeated studies can be carried out over a short time period without the need to wait for the previous dose to wash out. Water turnover rates from total diurnal energy expenditure studies measured by this method were not significantly different from those obtained by the zinc reduction method.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200220704
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  • 5
    Electronic Resource
    Electronic Resource
    Urinary metabolites of L-threonine in type 1 diabetes determined by combined gas chromatography/chemical ionization mass spectrometry (1986)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1986), S. 535-540 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metabolic profiling of urinary organic acids from patients with juvenile-onset (Type 1) diabetes mellitus have revealed significantly elevated levels of 2-hydroxybutyric acids. To test the hypothesis that these metabolites, as well as 4-deoxyerythronic acid, are derived from L-threonine, stable isotope-labeled threonine was infused into an insulin-deficient dog and the incorporation of 13C into these metabolites was monitored by gas chromatography/mass spectrometry. Electron ionization was relatively insensitive, but positive chemical ionization with ammonia as the reactant gas gave both protonated molecules and [M+NH4]+ ions, which could be analysed by selected ion monitoring. The isotope-labeled species of 2-hydroxybutyric, 4-deoxyerythronic and 4-deoxythreonic acids were observed, but 13C was not incorporated into other organic acids. Thus, it is proposed that L-threonine is a precursor of these metabolites.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200131004
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  • 6
    Electronic Resource
    Electronic Resource
    A computer model of the fixed bed catalytic reactor: The adiabatic and quasi-adiabatic cases (1963)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 9 (1963), S. 129-133 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A digital computer model of the adiabatic-fixed bed catalytic reactor is developed which includes axial dispersion of heat and mass, interparticle heat and mass transport, and intraparticle diffusion of reacting species. The influence of these transport processes upon conversion and yield is discussed. The model is readily extended to nonisothermal, nonadiabatic cases in the absence of radial gradients.The technique of computer solution avoids the inherent instability problem associated with explicit techniques as applied to flux boundary condition problems which involve flow, diffusion, and reaction.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690090128
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  • 7
    Electronic Resource
    Electronic Resource
    1-Bis(carboxymethyl)amino-butandion-2,3-dioxim als ambifunktioneller Ligand in Komplexen der 3d-Elemente (1981)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 479 (1981), S. 147-157 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1-Bis(carboxymethyl)amino-butanedione-2,3-dioxime as an Ambifunctional Ligand in Complexes of 3d ElementsIn acid solution 1-bis(carboxymethyl)amino-butanedione-2,3-dioxime H4A affords octahedral 1,1 complexes MII(H2A)(H2O)x (MII = Cu, Ni, Co) coordinating as a tetradentate ligand by the imino diacetic acid group and the oxime group in 2-position. At 4.5 〈 pH 〈 8 Ni(H2A)(H2O)x and Cu(H2A)(H2O)x are deprotonated, in addition to Ni(HA)- the binuclear chelate [Ni2(HA)2]2- is formed. In solution containing a surplus of ligand H4A also the planar chelate [Ni(HA)2]4- with the donor set N4 can be detected. The transition from [Ni(HA)]- to [Ni(HA)2]4- is connected with a change of the coordination sphere (imino diacetic acid group → dioxime group) and the cis-trans isomerization of at least one oxime group.Protonation and stability constants are given and the properties of solid complexes are described.
    Notes: 1-Bis(carboxymethyl)amino-butandion-2,3-dioxim H4A bildet in saurer Lösung oktaedrische 1,1-Komplexe MII(H2A)(H2O)x (MII = Cu, Mi, Co), in denen es vierzählig über die Iminodiessigsäure- und die Oximgruppe in 2-Stellung koordiniert. Ni(H2A)(H2O)x und Cu(H2A) (H2O) unterliegen im neutralen Gebiet der Deprotonierung; im Falle des Nickel(II) entsteht neben Ni(HA)- auch das binucleare Chelat [Ni2(HA)2]2-. In Lösungen mit einem Ligandenüberschuß kann der planare Komplex [Ni(HA)2]4- mit dem Donatorsatz N4 nachgewiesen werden. Beim übergang von [Ni(HA)]- in [Ni(HA)2]4- wechselt das Nickel(II) die Koordinationssphäre; gleichzeitig erfolgt die Cis-trans-Isomerisierung mindestens einer Oximgruppe.Protonierungs- und Komplexstabilitätskonstanten sowie die Eigenschaften kristalliner Komplexe werden mitgeteilt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19814790818
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  • 8
    Electronic Resource
    Electronic Resource
    Electrochemical study of iproniazid and its analytical determination by differential pulse polarography (1994)
    Weinheim : Wiley-Blackwell
    Electroanalysis 6 (1994), S. 491-496 
    Details
    ISSN: 1040-0397
    Keywords: Iproniazid ; Differential pulse polarography ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Iproniazid was found to be irreversibiy reduced in two steps, involving the exchange of two electrons and two protons each, by using tast polarography, normal pulse polarography (NPP), and cyclic voltammetry (CV). The rate constants of these two steps were found to be 5.8 × 10-6 and 4.2 × 10-6 and 4.2 × 10-6 cm s-1, respectively, and their corresponding diffusion coefficients 4.5 × 10-5 and 8.3 × 10-5 cm2 s-1, Also, α, the coefficient of cathodic transfer, was found to be 0.20 to 0.25 for the first peak and 0.17 to 0.15 for the second. On the basis of the electrochemical study performed, a differential pulse polarographic method for the determination of iproniazid over the concentration range of 5 × 10-7 M to 1 × 10-4 M was developed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140060522
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  • 9
    Electronic Resource
    Electronic Resource
    Oxidation der Pb-Ca-Legierungen in flüssigem Zustand (1978)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 29 (1978), S. 815-820 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Oxidation of PbCa alloys in the liquid stateThe effect of various temperatures, the composition of the alloy and the corroding atmosphere is studied with a thermobalance during the oxidation of molten PbCa alloys. The rate controlling step of the oxidation depends on the test conditions. The results obtained at 700°C are in agreement with data found in literature and according to which the oxidation increases with the Ca content; in this range calcium is subject to preferential oxidation. At 600°C and temperatures below that the addition of calcium does not only not increase oxidation but may give rise to a decrease.
    Notes: Mit einer Thermowaage wird die Wirkung verschiedener Temperaturen, der Zusammensetzung der Legierung und der Zusammensetzung der angreifenden Atmosphäre bei der Oxidation geschmolzener Pb-Ca-Legierungen untersucht. Der geschwindigkeitsbestimmende Schritt der Oxidation hängt von den Versuchsbedingungen ab. Bei 700°C bestätigen die bei der vorliegenden Untersuchung erhaltenen Ergebnisse die Literaturangaben, wonach die Oxidation bei zunehmendem Ca-Gehalt ansteigt; dabei wird das Calcium vorzugsweise oxidiert. Dagegen wird bei 600°C und darunter die Oxidation durch Zusatz von Calcium nicht nur nicht verstärkt, sondern sogar verringert.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19780291206
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  • 10
    Electronic Resource
    Electronic Resource
    Zur Fluiddynamik des Steigrohrs eines katalytischen Crackers (FCC) (1995)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 67 (1995), S. 1092-1093 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330670919
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