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  • Chemistry  (11)
  • Biochemistry and Biotechnology
  • 1980-1984  (11)
Document type
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1994-1997 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Mono- and Divinyl Ethers of Tetra(oxyethylene)The derivatives 3, 4, and 6 - 8 of tetra(oxyethylene) (1) are prepared. 3, 4, and 8 are obtained by direct vinylation in the presence of vinyl acetate and mercury acetate. 6 and 7 are prepared by esterification of 1 with 3,5-dinitrobenzoyl chloride (5) and represent intermediates for the hydroxy protected vinyl monomer 8.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 585-593 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(1-aminoethylene) (polyvinylamine) (4) was prepared by hydrazinolysis of poly(1-succinimidoethylene) (2) [poly(N-vinylsuccinimide)]. The water-soluble polymer 4, with more than 95% of primary amino groups, was used as basic material for the synthesis of macromolecular complex forming reagents. By the reaction of poly(1-ammonioethylene chloride) (3) [poly(vinylamine hydrochloride)] with 2-pyridinecarbaldehyde a complex forming polymer 5 was obtained, which is highly selective for iron. Poly{1-[bis(carboxymethyl)amino]ethylene} (6) from 4 and chloroacetic acid is a reagent for copper, whereas poly[1-(3-methylthioureido)-ethylene] (7) from 4 and N-methylisothiocyanate shows a good selectivity for mercury. The ultrafiltration technique allows a continuous procedure for the separation of the polymer complexes. The formation and stability of the prepared complexes of 4and its derivatives 5, 6, and 7 in homogeneous phase are investigated and discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 969-976 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyurethanes 6 and 7 based on poly(oxyethylene) (5) were synthesized and investigated for the application as macromolecular chelating agents. 4,4′-Diaminobenzil (3c) and 4,4′-diaminobenzil monoxime (4a) were prepared as monomer precursors in 70 and 80% yield. Copolymers were obtained in yields between 40 and 60% by polyaddition of the corresponding diisocyanates 3d and 4b to poly(oxyethylene) (5) of different chain length and characterized by IR and 13C NMR spectroscopy. The application of the resulting polyurethanes containing functional aromatic block units as polychelatogenes was studied in homogeneous phase by membrane filtration. The metal content was determined in both the filtrate and the retentate and in the case of Ni2+ at different pH values. At pH 2, for example, the molar binding capacity of a polyurethane sample of 6 was 3 times as high as that of 5.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Macromolecular chelating agents have been synthesized and investigated for the complexation with various metals in homogeneous phasing using membrane filtration. Quite a number of water-soluble basis polymers such as poly(vinylamine), poly(acrylic acid), poly(ethyleneimine), and copolymers, and their derivatives are listed and discussed in respect to their application for the chelation of transition metals.The polymers had molecular masses between 20000 and 200000 daltons. The application of membrane filtration rendered it possible to separate excess metallic ions from the polymer chelate in a continuous or discontinuous process. Studies on the metal-binding capacity of the polymer ligand exhibited the possiblity of preparation of macromolecular chelating agents which are selective for different metals. There after, the introduction of chelating groups such as iminodiacetic acid, thiourea, pyridine-2-aldimine, and others, improved significantly the selectivity for the metals copper, nickel, palladium, mercury, iron, gold, and platinum.For the regeneration of the polymer ligands electrolysis and protolysis can be used. The macromolecular chelates remained water-soluble independent of the chelated metal and the polymeric chelating agent. According to these studies, certain metals can be removed selectively from waste water or other diluted solutions in homogeneous phase by the application of polymeric chelating agents.
    Notes: Makromolekulare Chelatogene wurden zur Komplexierung mit verschiedenen Metallen in homogener Phase unter Anwendung der Membranfiltration synthetisiert und untersucht. Eine Anzahl von wasserlöslichen Basispolymeren, wie z. B. Poly(vinylamin), Poly(acrylsäure), Poly(ethylenimin), ihre Copolymere und Derivate wurden im Hinblick auf ihre Anwendung zur Komplexbildung von Übergangsmetallen dargestellt und untersucht.Die Molmassen der Polymere lagen zwischen 20000 und 200000 Daltons. Die Anwendung der Membranfiltration ermöglicht die Abtrennung von überschüssigen Metallionen vom Polymerkomplex in einem kontinuierlichen oder diskontinuierlichen Verfahren. Studien über die Metallbindungskapazitäten der Polymerliganden zeigten, daß es möglich ist, makromolekulare Chelatogene darzustellen, die für verschiedene Metalle selektiv sind. Danach verbesserte die Einführung von chelatogenen Gruppen, wie Iminodiessigsäure, Thioharnstoff, Pyridin-2-aldimin und andere, signifikant die Selektivität für die Metalle Kupfer, Nickel, Palladium, Quecksilber, Eisen, Gold und Platin.Zur Regenerierung der Polymerliganden kann die Elektrolyse oder Protolyse verwendet werden. Die makromolekularen Komplexe blieben unabhängig vom komplexierten Metall und des polymeren Chelatogens wasserlöslich. Nach diesen Studien können bestimmte Metalle selektiv aus Abwasser oder anderen verdünnten Lösungen durch die Anwendung von polymeren Chelatogenen in homogener Phase entfernt werden.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 113 (1983), S. 141-152 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Synthese und Anwendung von mehreren polymeren Agentien auf der Basis von Poly(vinylalkohol), die funktionelle Gruppen mit Phosphor enthalten, wurde untersucht. Die Monomer- und Polymersynthese von Phosphorsäure und ihrer Derivate mit Poly(vinylalkohol) werden beschrieben. Durch polymeranaloge Reaktionen mit Mono- und Diethylestern der Phosphorsäure wurden multifunktionelle Derivate dieses hydrophilen Polymers erhalten. Untersuchungen zu den Komplexbildungseigenschaften der Polychelatogene wurden mit Hilfe der Membranfiltration für Nickel bei verschiedenen pH-Werten durchgeführt. Typische Komplexierungskurven wurden nach Bestimmung des Metallgehalts im Filtrat und Retentat erhalten. Unterschiede der polymeren Träger und Einflüsse der funktionellen Gruppen werden diskutiert.
    Notes: Synthesis and application of several polymeric agents based on poly(vinylalcohol) with phosphorus containing functional groups were investigated. Monomer and polymer syntheses of phosphoric acid and derivaties with poly(vinylalcohol) are described. Multifunctional derivaties of the hydrophilic polymer were obtained by polymer-analogous reactions with mono and diethyl esters of phosphoric acid. Studies on chelating properties of the polychelatogenes at different pH values for nickel were carried out by means of membrane filtration. Metal determination in filtrate and retentate yielded typical chelating curves. Differences of the polymer supports and influences of the functional groups are discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Geschwindigkeitsbestimmung der säurekatalysierten Racemisierung von proteinogenen AminosäurenZur gaschromatographischen Bestimmung von Aminosäure-Enantiomeren in Proteinen und Peptiden müssen diese vorher sauer gespalten werden; die hierbei gleichzeitig ablaufende, durch Säure katalysierte Racemisierung führt zu erhöhten Anteilen von D-Enantiomeren, sowohl bei den gebundenen als auch bei den freien Aminosäuren. Zur Abschätzung dieses Beitrages wurde die Racemisierung aller proteinogenen Aminosäuren als Funktion der Zeit in stark saurem Medium bestimmt. Die erwartete Kinetik pseudoester Ordnung wurde in allen Fällen gefunden. Die ermittelten Inversionsgeschwindigkeiten sind mit den beim Insulin und Albumin gefundenen vergleichbar, außer in der Anfangsphase der Acidolyse, während der die Spaltung der Peptidbindungen noch unvollständig ist. Der größte Anteil der in Insulin und Albumin gefundenen D-Aminosäuren entsteht durch Racemisierung der freigesetzten Aminosäure und kann durch Verfolgung der Zeitabhängigkeit und Extrapolation auf t = 0 berücksichtigt werden. Die Racemisierungsgeschwindigkeit der proteinogenen Aminosäuren nimmt in der folgenden Reihenfolge ab: Asp = Cys 〉 Pro 〉 Glu 〉 Met 〉 His 〉 Leu 〉 Lys 〉 Phe 〉 Ala 〉 Tyr 〉 Arg 〉 Trp 〉 Val 〉 Ile 〉 Ser 〉 Thr.
    Notes: Determination of the enantiomeric composition of the amino acids of protein or peptide hydrolyzates by gas chromatography involves a hydrolytic step, in the course of which racemization may occur, leading to erroneously high values of D-enantiomer. Racemization of both protein-bound and free amino acids contribute to this formation of D-enantiomers. In order to estimate the latter contribution, the time-dependance of racemization for all protein amino acids during exposure to strong acid has been determined. The expected pseudo-first-order kinetic was confirmed in all cases. The rate constants are compared with those obtained for insulin and albumin and found to be of similar magnitude, except for the initial period of hydrolysis, when cleavage of peptide bonds is still incomplete. Most of the racemate generated during hydrolysis can be accounted for by a study of the time-dependance of racemization and extrapolation to zero-time. Racemization of the protein amino acids is decreasing in the following order: Asp = Cys, Pro, Glu, Met, His, Leu, Lys, Phe, Ala, Tyr, Arg, Trp, Val, Ile, Ser, Thr.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the Insulin Segment B 13-20 with the Liquid-Phase Method and Control of the Synthesis by 13C NMR Spectroscopy of the Support-bound PeptidesThe protected partial sequence B 13-20 of the insulin B chain has been synthesized stepwise according to the liquid-phase method: Boc-Glu(Bzl)-Ala-Leu-Tyr(Bzl)-Leu-Val-Cys(Bzl)-Gly-OPOE (8) [POE = polyoxyethylene]. The partially protected octapeptide Boc-Glu-Ala-Leu-Tyr(Bzl)-Leu-Val-Cys(Bzl)-Gly-OH (9) was split off from the solubilizing polymeric support by alkaline saponification. Each synthetic step was controlled by 13C NMR spectroscopy of the polyoxyethylene-bound peptides 1-8. The 13C NMR spectra (20.63 MHz) of all polymer-bound intermediates 1-8 and of the cleaved octapeptide 9 were in agreement with the expected signal positions of the amino acid residues. However, the 100.62-MHz 13C NMR spectrum of the polymer-bound octapeptide 8 revealed a benzyl rearrangement at the tyrosine ring. Beginning with the hexapeptide 6 the onset of an α-helical secondary structure was found by circular dichroism measurements. This conformation also reflects in the 13C NMR spectra by typical shifts of the CO, Cα and side-chain signals.
    Notes: Die geschützte Partialsequenz B 13-20 der Insulin-B-Kette wurde schrittweise mit Hilfe der Liquid-Phase-Methode aufgebaut: Boc-Glu(Bzl)-Ala-Leu-Tyr(Bzl)-Leu-Val-Cys(Bzl)-Gly-OPOE (8) [POE = Polyoxyethylen]. Das partiell geschützte Octapeptid Boc-Glu-Ala-Leu-Tyr(Bzl)-Leu-Val-Cys(Bzl)-Gly-OH (9) wurde durch alkalische Verseifung vom solubilisierenden Polymerträger abgespalten. Jede Synthesestufe wurde durch 13C-NMR-Spektroskopie der polyoxyethylengebundenen Peptide 1-8 kontrolliert. Die 13C-NMR-Spektren (20.63 MHz) aller polymergebundenen Zwischenprodukte 1-8 und vom abgespaltenen Octapeptid 9 zeigten übereinstimmung mit den erwarteten Signallagen der Aminosäurebausteine. Im 100.62-MHz-13C-NMR-Spektrum des polymergebundenen Octapeptids 8 wurde jedoch eine Benzylumlagerung am Tyrosinring entdeckt. Ab dem Hexapeptid 6 ergeben sich anhand von Circulardichroismus-Messungen eindeutige Hinweise auf die Ausbildung einer α-helikalen Sekundärstruktur. Diese Konformation spiegelt sich auch in den 13C-NMR-Spektren durch typische Verschiebungen der CO-, Cα- und Seitenketten-Signale wider.
    Additional Material: 7 Ill.
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  • 8
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Microbiological Formation of 2-(4-Bromophenyl)-2-ethoxyoxirane and Crystal Structure Determination of the Dimerization Product meso-2,5-Bis(4-bromophenyl)-2,5-diethoxy-1,4-dioxanep-Bromo-2-hydroxyacetophenone (3) is metabolized by baker's yeast to give the optically active epoxy ether 1a which is stable in crystalline form. The structural assignment is based mainly on the NMR spectra. - The stereochemical course of the dimerization to the 1,4-dioxane derivative 2a is discussed on the basis of the X-ray structure of the dimer.
    Notes: p-Brom-2-hydroxyacetophenon (3) wird durch Bäckerhefe zum optisch aktiven Epoxyether 1a metabolisiert, der im kristallinen Zustand stabil bleibt. Die Strukturzuordnung erfolgt im wesentlichen durch NMR-Spektren. - Der stereochemische Verlauf der Dimerisierung zum 1,4-Dioxan-derivat 2a wird auf der Basis der Röntgenstruktur des Dimeren diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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