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  • 1
    Electronic Resource
    Electronic Resource
    Functional polymers, XL. Syntheses of mono- and di(4-methoxy)benzotriazolesubstituted 2,4-dihydroxyaceto(or benzo)phenones (1986)
    Springer
    Monatshefte für Chemie 117 (1986), S. 805-819 
    Details
    ISSN: 1434-4475
    Keywords: Functional polymers ; 2(2-Hydroxyphenyl)2 H-benzotriazoles ; 2-Hydroxyphenylaceto(benzo)phenones ; Azo coupling ; Reductive cyclization ; Ultraviolet stabilizers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurden acht Benzotriazole und 4-Methoxybenzotriazole — mono- oder disubstituierte Derivate von 2,4-Dihydroxyaceto(oder benzo)phenonen — über Azokopplung von 4-Methoxy-2-nitrobenzoldiazoniumchlorid mit 2,4-Dihydroxyaceto(oder benzo)phenonen und nachfolgender reduktiver Cyclisierung synthetisiert. Reine monosubstituierte Verbindungen waren sehr schwer herzustellen. Sorgfältige Wahl despH-Wertes für die Azo-Kupplung und geeignete Reagentien für die reduktive Cyclisierung waren dabei wesentlich. Alle Verbindungen wurden mittels UV-, IR-,1H-NMR- und13C-NMR-Spektren und Elementaranalysen charakterisiert. Die synthetisierten Verbindungen besitzen jeweils eine 2-(2-Hydroxyphenyl)-2H-benzotriazol-Einheitund eine 2-Hydroxyaceto(oder benzo)phenon-Einheit im gleichen Molekül und stellen effektvolle und nützliche Ultraviolett-Absorber dar.
    Notes: Abstract Eight benzotriazoles and (4-methoxy)benzotriazoles, mono- or di-substituted derivatives of 2,4-dihydroxyaceto(or benzo)phenone were synthesized by azo coupling of (4-methoxy)2-nitrobenzenediazonium chloride with 2,4-dihydroxyaceto(or benzo)phenone followed by reductive cyclization. Pure mono-substituted compounds were very difficult to prepare. Careful selection of thepH for the azo coupling and selection of the proper reagents for the reductive cyclization were essential. All compounds were characterized by their ultraviolet, infrared1H and13C NMR spectra and their elemental analysis. These compounds have both the 2(2-hydroxyphenyl)2H-benzotriazole unit and a 2-hydroxyaceto(or benzo)phenone unit in the same molecule and are effective and useful ultraviolet absorbers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00810072
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  • 2
    Electronic Resource
    Electronic Resource
    Optical activity measurements in solids 5. Optical rotation of natural polymersDedicated to Professor Milan Lazár on the occasion of his 65th birthday, with warmest personal wishes. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 25-36 
    Details
    ISSN: 0959-8103
    Keywords: optical activity ; solid-state measurements ; natural polymers ; suspension ; birefringence ; isorefractive media ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The optical activity of ten natural-type polymers [poly(α-aminoacids), polysaccharides, proteins and nucleic acids] was measured in solution, as solid powders in suspension, and where possible in the form of films. In some cases the specific rotation of powder samples showed significant differences to the values obtained from solution measurements. The discrepances seem to reflect the arrangements of polymer chains in supermolecular assemblies in the polymer solid state.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330104
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  • 3
    Electronic Resource
    Electronic Resource
    Optical activity measurements in solids 7. Polylactides and poly(β-hydroxybutyrates)This paper is dedicated to Professor Hermann Janeschitz Kriegl on the occasion of his 70th Birthday with our warmest wishes. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 34 (1994), S. 433-442 
    Details
    ISSN: 0959-8103
    Keywords: optical activity ; polylactides ; poly(β-hydroxybutyrates) ; solid state measurements ; circular dichroism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The optical activities of poly-(R)-lactide, poly-(S)-lactide, poly(β-hydroxybutyrate) and two β-hydroxyvalerate copolymers were measured in solution, as solid powders in suspension, and where possible, as films. Poly-(+)-3-methyl-1-pentene was also reinvestigated. In some cases the specific rotation values of powder samples showed significant differences from the values of the solution measurements. The discrepancies of the data observed seem to reflect the local environment of the polymer chains in supermolecular assemblies and consequently the solid state structure(morphology)of the polymers.The circular dichroism (CD) spectra of the polymers were also measured in solution and in the form of their films. For comparison, the CD spectra of the naturally occurring protein casein and of the synthetic polypeptide poly-(L)-proline were also measured.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210340413
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