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  • 1
    Electronic Resource
    Electronic Resource
    Lichtinduzierte Umorientierung der optischen Achse in LC-Farbstoff-CopolymerenHerrn Prof. Dr. D. Braun zum 60. Geburtstag gewidmetVortrag anläßlich der Tagung der Fachgruppe “Makromolekulare Chemie” der Gesellschaft Deutscher Chemiker über “Polymere und Licht”. in Bad Nauheim vom 7. bis 9. Mai 1990. (1990)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 183 (1990), S. 103-113 
    Details
    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: The influence of linearly and circularly polarized light on the state of order of nematic dye-copolymers is investigated. For a nematic model system we have shown that the optical axis of these systems can be reorientated with linearly polarized light in a well defined manner. Furthermore these investigations prove that the isomerisation cycles of the azo dye is responsible for the described properties. By selection of circularly polarized light the same transmission behaviour as shown by selectively reflecting materials, i. e. cholesteric liquid crystals, was observed.
    Notes: Untersucht wird der Einfluß von linear und zirkular polarisiertem Licht auf den Ordnungszustand von nematischen Farbstoff- Copolymeren. Am Beispiel eines Modellsystems wird gezeigt, daß mit linear polarisiertem Licht die optische Vorzugsachse dieser Systeme gezielt reorientiert werden kann. Die Untersuchungen zeigen, daß der Isomerisierungszyklus des Azofarbstoffes für diese Eigenschaft des Materials verantwortlich ist Nach Bestrahlen der Probe mit zirkular polarisiertem Licht wird für das Polymere das gleiche Transmissionsverhalten beobachtet. Wie es auch selektivreflektierende Materialien, z. B. cholesterische Flüssigkristalle, aufweisen.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1990.051830105
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  • 2
    Electronic Resource
    Electronic Resource
    Notiz zur Synthese von Derivaten des 1-Hydroxyimidazol-3-oxids (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 3900-3905 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751081224
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  • 3
    Electronic Resource
    Electronic Resource
    A group 4 metallocene template synthesis of β,γ-unsaturated ε-hydroxy carboxylic acids (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2119-2126 
    Details
    ISSN: 0009-2940
    Keywords: Zirconocene complexes ; (Metaloxy)carbene complexes ; Template reaction, organometallic ; Steroid side-chain attachment ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of (butadiene)zirconocene with hexacarbonyltungsten gives the metallacyclic [(π-allyl)zirconoxy]carbene complex 7. This reagent adds to a variety of ketones to yield chiral nine-membered metallacyclic ring systems (8). These systems are thus formed by means of 1,4-selective coupling reactions of 1,3-butadiene with W(CO)6 and an organic carbonyl compound at the zirconocene template. The ketones subjected to react with 7 include benzophenone, methyl vinyl ketone, cyclopentanone, and 3-methoxyestra-1,3,5(10)-trien-17-one (12). The coupling products of 7 with cyclopentanone (8c) and 12 (8d-A) were characterized by X-ray crystal structure analyses. Of the four possible diastereomeric nine-membered metallacyclic coupling products of 7 with 12 a single isomer [8d-A with (13'S,17'R,2,3,4-pS) configuration] was formed with ≥98% selectivity and isolated in 95% yield. Treatment of the complexes 8 in tetrahydrofuran with water and pyridine N-oxide very effectively removed both transition metals with the formation of the corresponding β,γ-unsaturated ε-hydroxy carboxylic acids. The overall reaction sequence has thus converted the steroid ketone 12 very selectively to 5-[3-methoxy-17β-hydroxyestra-1,3,5(10)-trien-17α-yl]-(E)-pent-3-enoic acid (10d)
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260923
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of vertical alignment on the performance of bubble and foam fractionation columns (1975)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 21 (1975), S. 400-402 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    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/aic.690210228
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  • 5
    Electronic Resource
    Electronic Resource
    Oxazolone, IV1) Einige Reaktionen von 4-Oxazolin-2-onen mit primären Aminen (1976)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 1471-1474 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxazolones, IV 1). - Some Reactions of 4-Oxazolin-2-ones with Primary Amines4-Oxazolin-2-ones 1 can be converted into 4-imidazolin-2-ones 6 by primary amines. The reactions are catalysed by hydrochlorides of the amines. Competing hydrolytic ring cleavage of 1 takes place; hence 2,3-diphenylindole (7) is formed as by- or main product in the presence of aniline/aniline hydrochloride.
    Notes: 4-Oxazolin-2-one 1 lassen sich durch primäre Amine in 4-Imidazolin-2-one 6 überführen. Die Umsetzungen werden durch die Hydrochloride der Amine katalysiert. Konkurrierend tritt hydrolytische Ringöffnung von 1 ein; in Gegenwart von Anilin/Anilin-hydrochlorid entsteht daher 2,3-Diphenylindol (7) als Neben- oder Hauptprodukt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197619760736
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  • 6
    Electronic Resource
    Electronic Resource
    Oxazolone, I. 4-Imidazolin-2-one durch Umlagerung von 2-Oxo-4-oxazolin-3-carboxamiden (1976)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 208-220 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxazolones, I.  -  4-Imidazolin-2-ones by Rearrangement of 2-Oxo-4-oxazoline-3-carboxamidesThe addition of N-unsubstituted 4-oxazolin-2-ones 1 to isocyanates leads to 2-Oxo-4-oxazoline-3-carboxamides 2. In the presence of strong acids ring cleavage of 2 takes place at elevated temperature, followed by ring closure to 4-imidazolin-2-ones 5. Via this novel route good yields of aromatic as well as aliphatic substituted 5 are obtained. The related 2-oxobenzoxazoline-3-carboxamides 7 do not rearrange under the same conditions. - Spectra and structures of 2, 5 and 7 are discussed.
    Notes: Die Addition N-unsubstitierter 4-Oxazolin-2-one 1 an Isocyanate führt zu 2-Oxo-4-oxazolin-3-carboxamiden 2. Letztere erleiden in Gegenwart starker Säuren bei höherer Temparatur Ringaufspaltung und recyclisieren zu 4-Imidazolin-2-onen 5. Auf diesem neuen Reaktionsweg lassen sich sowohl aromatisch als auch aliphatisch substituierte 4-Imidazolin-2-one 5 in guter Ausbeute darstellen. Die verwandten 2-Oxobenzoxazolin-3-carboxamide 7 lagern sich unter gleichen Bedingungen nicht um.  -  Spektren und Strukturen von 2, 5 und 7 werden diskutiert.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197619760203
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  • 7
    Electronic Resource
    Electronic Resource
    Oxazolone, V. 4-Oxazolin-2-one aus N-(2-Oxoalkyl)-1-imidazolcarboxamiden (1976)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 1862-1872 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxazolones, V. - 4-Oxazolin-2-ones from N&-(2-Oxoalkyl)-l-imidazolecarboxamidesα-Aminoketones 1 react with di-1-imidazolyl ketone to give N-(2-oxoalkyl)-l-imidazole-carboxamides 2. On heating 2 to above their melting points, cyclization takes place to 4-oxazolin-2-ones 4 with the extrusion of a molecule of imidazole. In some cases the cyclization apparently proceeds via a-isocyanato ketones 3 (IR spectra). Spectra and structures of 2 and 4 are discussed.
    Notes: Bei der Umsetzung von α-Aminoketonen 1 mit Di-1-imidazolyl-keton entstehen die N-(2-Oxoalkyl)-1-imidazolcarboxamide 2. Beim Erhitzen über ihren Schmelzpunkt gehen diese unter Abspaltung von Imidazol in 4-Oxazolin-2-one 4 über. In einigen Fällen erfolgt die Cyclisierung offenbar über α-Isocyanatoketone 3 (IR-Spektren). Spektren und Strukturen von 2 und 4 werden diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197619761017
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  • 8
    Electronic Resource
    Electronic Resource
    Oxazolone, II. Über die saure Hydrolyse von N-tert-Butyl-2-oxo-4,5-diphenyl-4-oxazolin-3-carboxamid (1976)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 788-792 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxazolones, II.  -  Acid Hydrolysis of N-tert-Butyl-2-oxo-4,5-diphenyl-4-oxazol-ox amideReaction of N-tert-butyl-2-oxo-4,5-diphenyl-4-oxazoline-3-carboxamide (2) with a mixture of glacial acetic acid and 63 hydrobromic acid affords (±)-(a-benzoy1benzyl)ammonium bromide (4. HBr) and 4,5-diphenyl-4-imidazolin-2-one (7). 4. HBr is formed by hydrolysis of the intermediate 4,5-diphenyl-4-oxazolin-2-one (l), 7 probably via (±)-N-(a-benzoyl-benzy1)-N′-tert-butylurca (5) and 1 -tert-butyl-4,5-diphenyl-4-imidazolin-2-one (6). The investigations involved new methods for the synthesis of 1, 4, and 7.
    Notes: N-tert-Butyl-2-oxo-4,5-diphenyl-4-oxazolin-3-carboxamid (2) reagiert mit einer Mischung aus Eisessig und 63 proz. Bromwasserstoffsäure zu (±)-(α-Benzoylbenzyl)ammoniumbromid (4·HBr) und 4,5-Diphenyl-4-imidazolin-2-on (7). 4. HBr entsteht durch Hydrolyse des intermediär auftretenden 4,5-Diphenyl-4-oxazolin-2-ons (l), 7 wahrscheinlich über (±)-N-(cr-Benzoylbenzyl)-N′-tert-butylharnstoff (5) und 1 -tert-Butyl-4,5-diphenyl-4-imidazolin-2-on (6). Aus den Untersuchungen resultieren neue Darstellungsverfahren für die Verbindungen 1, 4 und 7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197619760421
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  • 9
    Electronic Resource
    Electronic Resource
    Oxazolone, III1) Über die Umwandlung von 4-Oxazolin-2-onen in 1-(2-Oxoalkyl)- 1,3,5-triazin-2,4,6(1H,3H,5H)-trione und umgekehrt (1976)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 1465-1470 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxazolones, III . - The Transformation of 4-Oxazolin-2-ones into 1-(2-0xoalkyl)-1,3,5-tri-azine-2,4,6(1H,3H,SH)-triones and vice versaN-Phenyl(2-oxo-4-oxazolin-3-carbox)amides 2a- c are converted into 1 -(2-oxoalkyl)-3,5-di- phenyl-l,3,5-triazine-2,4,6(lH,3H.5H)-triones 4 on reaction with phenyl isocyanate. The reaction is catalysed by potassium cyanate and presumably proceeds via N-(2-oxo-4- oxazolin-3-ylcarbonyl)-N,N′-diphenylurea derivatives 3. Tris(2-oxoalkyl)-l,3,5-triazine-2,4,6 (lH,3H,SH)-triones 6 can be synthesized from trisodium 1,3,5-triazinetriolate (5) and %-halo- ketones. Sonie of the compounds 4 and 6 rearrange into 4-oxazolin-2-ones 1 at elevated temperature in the presence of potassium cyanate.
    Notes: N-Phenyl(2-oxo-4-oxazolin-3-carbox)amide 2a- c reagieren mit Phenylisocyanat zu 1 -(∼-OXO- alkyl)-3,5-diphenyl-1,3,5-triazin-2,4,6(lH,3H,5H)-trionen 4. Die Reaktion wird durch Kaliumcyanat katalysiert und verläuft vermutlich über N-(2-Oxo-4-oxazolin-3-ylcarbonyl)- N,N′-diphenylharnstoffderivate 3. Tris(2-oxoalkyl)-l,3,5-triazin-2,4,6-(IW,3N,5∼)-trione 6 sind aus Trinatrium-l,3,5-triazintriolat (5) und a-Halogenketonen zugänglich. Einige der Produkte 4 und 6 lagern sich bei höherer Temperatur und in Gegenwart von Kaliumcyanat in 4-Oxazolin-2-one 1 um.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197619760735
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesen von 20-Carbaldehyden und 20-Carbonitrilen der Pregnanreihe aus (20S)-20-Hydroxymethylpregna-1,4-dien-3-on (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 1025-1032 
    Details
    ISSN: 0170-2041
    Keywords: Pregnanes ; Steroids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 20-Carbaldehydes and 20-Carbonitriles of the Pregnane Series Starting with (20S)-20-Hydroxymethylpregna-1,4-dien-3-oneAn efficient six-step approach to 3-protected (20S)-3β-hydroxypregna-1,5-diene-20-carbaldehydes 8 with potential importance in the synthesis of vitamin D analogues was developed starting with (20S)-20-hydroxymethylpregna-1,4-dien-3-one (1). Oxidation of the 22-hydroxy group of 1 by means of periodinane 2 (Dess-Martin reagent) furnished the aldehyde 3 without epimerization. 3 was protected selectively at C-22 as dimethyl acetal 5. Isomerization to 6 and subsequent reduction of the 3-carbonyl group with calcium borohydride furnished the 3β-alcohol 7a with high stereoselectivity. Cleavage of the acetal to 8a occurred in a homogeneous solution of acetic acid in the presence of small amounts of water and trifluoroacetic acid. After protection of the 3-OH group 8b-d were obtained in 54% overall yield. The in situ generated aldehyde N,N-dimethylhydrazones of 3, 8a, and 8b were converted in high yields with excellent chemoselectivity into the nitriles 12, 15a, and 15b with magnesium monoperoxyphthalate hexahydrate. The uniform (20S) stereochemistry of 3 and 8a-d was elucidated by 1H-NMR investigations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419941012
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