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  • 1
    Electronic Resource
    Electronic Resource
    A standard test mixture for assessing enantioselectivity of chiral phase capillary GC columns - CHIRAL-Test IThis test mixture is intended for routinely determining the enantioselective separation potential of capillary GC columns. In preference to an acronym, derived from the authors' names, we propose CHIRAL,-Test as a self-explicatory label for such routine. The CHlRAL-Test I presented here has been optimized towards probing the “chiral performance” of amide phases. for amide phases (1990)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 234-238 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns, glass ; Enantioselectivity test procedure ; Cyclodextrin/amide phase comparison ; Enantiomer separation ; Chiral resolution (cR) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A test mixture is proposed which allows assessment of the enantioselective separation potential of chiral amide phase capillary columns. This CHIRAL-Test I includes a range of chromatographically problematical substrates, covering the temperature range from 100-200°C. One test component, the N-pivaloyl leucine methyl ester enatiomers, may be used exemplarily to calculate chiral resolution (chirale Auflösung, cR). Unlike separation factors α, cR values take account of peak shape as well as of relative retention time of both enantiomers, and thus are a measure of affective chromatographic separation. In combination with the Grob test, the CHIRAL-Test may be used for characterizing the chromatographical properties of columns coated with chiral amide phases.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240130404
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and activity of dimeric bradykinin antagonists containing diaminodicarboxylic acid bridge residues (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Peptide Science 4 (1998), S. 289-293 
    Details
    ISSN: 1075-2617
    Keywords: Bradykinin antagonist ; dimer ; diaminodicarboxylic acid ; bridge residue ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enhancement of a ligand's interaction with a receptor through presenting the ligand in multimeric form is a topic of general interest. Thus dimerization of single-chain bradykinin antagonist peptides has previously been shown to be beneficial in terms of potency and duration of action. While crosslinking polypeptides at terminal positions using suitable dicarboxylic acids and diamines is comparatively straightforward synthetically, internal dimerizations are usually achieved through oxidation or double S-alkylations of cysteine residues, resulting in metabolically unfavourable disulphide and thioether cross-links. Using suitably modified standard solid-phase peptide synthesis protocols, dimeric bradykinin antagonist peptides [H-(d-Arg)-Arg-Pro-Hyp-Gly-Phe]2-X-[(d-Phe)-Leu-Arg-OH]2 were synthesized where X corresponds to a l,l-2,7-diaminosuberic or l,l-2,9-diaminosebacic acid residue, respectively. The biological activity of these peptides was comparable to that of conventional dimeric bradykinin antagonists cross-linked through cystine or bis(succinimido)alkyl bridges. © 1998 European Peptide Society and John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Aminobenzole, VI. Darstellung N-persubstituierter 1.3.5-Triamino-benzole über Dehydrobenzol-Zwischenstufen (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1440-1455 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Benzenes, VI. Preparation of N-persubstituted 1,3,5-Triaminobenzenes via Dehydrobenzene IntermediatesTris(dialkylamino)benzenes 1a-j and 4, halo-m phenylene diamines 2a-g and 9a, b, and halo-tris(dialkylamino)benzenes 10a-i are synthesized by the reaction of halobenzenes with sec. amines and phenyl lithium. Conclusions are drawn about the reaction steps, i.e., metalation, elimination, and addition to the benzyne, from the structure and isomer distribution of the products.
    Notes: Über die Reaktion von Halogenbenzolen mit sek. Aminen und Phenyllithium sind die Tris - dialkylamino-benzole 1a-j und 4, die halogenierten m-Phenylendiamine 2a-g und 9a, b sowie die Halogen-tris-dialkylamino-benzole 10 a-i zugänglich.  -  Aus der Struktur und der Isomerenverteilung der erhaltenen Produkte werden Schlüsse auf die einzelnen Reaktionsschritte (Metallierung, Eliminierung und Addition) gezogen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030516
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  • 4
    Electronic Resource
    Electronic Resource
    Aminobenzole, XII. Kinetik und Mechanismus der Alkylierung von 1,3,5-Tripyrrolidinobenzol (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 181-198 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminobenzenes, XII. Alkylation of 1,3,5-Tripyrrolidinobenzene - Kinetics and MechanismUpon reaction of 1,3,5-tripyrrolidinobenzene (1) with alkyl iodides, stable σ complexes 2a-c are formed besides quaternary N-alkylammonium salts 3a-c. Both by the formal kinetics of the reaction and reactivity gradation CH3 ≥ C2H5 ≥ CH(CH3)2 (28.5:1.0:0.12), an SN2 mechanism is established for this first (rate limiting) step of electrophilic aromatic substitution. Likewise, activation parameters characteristic of a typical SN2 reaction are found for the methyl σ complex formation (2a). In the case of isopropyliodide, an SN1 process competes with bimolecular substitution. Benzyl halides, on the other hand, yield exclusively σ complexes (2e-k); the C-reaction proceeds solely by an SN2 mechanism independent of the p-substituent (OCH3 → NO2). The correlation of 1g k with Hammett's σ constants shows a non-linear relationship, with an alltogether small substituent dependency.
    Notes: Bei der Umsetzung von 1,3,5-Tripyrrolidinobenzol (1) mit Alkyliodiden werden neben N-Alkyl-ammoniumsalzen 3a-c isolierbare σ-Komplexe 2a-c gebildet. Für diesen ersten (geschwindigkeitsbestimmenden) Schritt der elektrophilen aromatischen Substitution ist sowohl durch die Formalkinetik wie durch die Reaktivitätsabstufung CH3 ≥ C2H5 ≥ CH(CH3)2 (28.5:1.0:0.12) ein SN2-Mechanismus gesichert. Die Aktivierungsparameter für die Bildung des Methyl-σ-Komplexes 2a sind ebenfalls charakteristisch für eine klassische SN2-Reaktion. Bei der Isopropylierung konkurriert ein SN1-Prozeß mit der bimolekularen Substitution. Benzylhalogenide dagegen geben ausschließlich C-Reaktion zu den σ-Komplexen 2e-k; dabei wird unabhängig vom p-Substituenten (OCH3 → NO2) nur SN2-Reaktion gefunden. Die Korrelation von 1g k mit Hammettschen σ-Konstanten zeigt einen nicht-linearen Verlauf (bei insgesamt nur geringer Substituentenabhängigkeit).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100118
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  • 5
    Electronic Resource
    Electronic Resource
    Three-dimensional helical supramolecules - elucidation of magnetic ordering for an antiferromagnetic phase (1996)
    Weinheim : Wiley-Blackwell
    Advanced Materials 8 (1996), S. 647-651 
    Details
    ISSN: 0935-9648
    Keywords: 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
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adma.19960080809
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  • 6
    Electronic Resource
    Electronic Resource
    Konstitutions- und Konfigurationsstabilität eines Carbamoyltetracarbonyleisen-AnionkomplexesDiese Arbeit wurde von der Deutschen Forschungsgemeinschaft und dem Fonds der Chemischen Industrie unterstützt. (1975)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 87 (1975), S. 489-490 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General 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/ange.19750871310
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  • 7
    Electronic Resource
    Electronic Resource
    Intramolekularer Ladungsübergang bei Dialkylamino-nitrobiphenylen (1971)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 83 (1971), S. 621-622 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General 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/ange.19710831610
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  • 8
    Electronic Resource
    Electronic Resource
    Amphiphilic liquid-crystalline networks  -  phase behavior and alignment by mechanical fields (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 16 (1995), S. 435-447 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A cross-linked polysiloxane carrying non-ionic amphiphilic side-groups attached with their hydrophobic end to the polymer backbone is synthesized. The amphiphilic groups are selectively deuterated at the α-position of the hydrophobic alkyl chains. The phase behavior with water is studied by deuterium nuclear magnetic resonance spectroscopy. A lamellar phase (La) is observed on the low-water-concentration side of the liquid-crystalline regime. The domains of the La-phase can be aligned macroscopically by uniaxial compression of the sample.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1995.030160605
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  • 9
    Electronic Resource
    Electronic Resource
    Unterschiedliche [4 + 2]-Cycloaddukte aus 7,7-Difluor- und 7,7-Dialkoxy-1,3,5-cycloheptatrienen mit 4-Phenyl-1,2,4-triazolin-3,5-dion (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 3427-3435 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [4 + 2] Cycloadducts with Alternate Structure from 7,7-Difluoro- and 7,7-Dialkoxy-1,3,5-cycloheptatrienes and 4-Phenyl-1,2,4-triazoline-3,5-dioneWith 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), 7,7-difluoro-, 7,7-dimethoxy-, 7,7-(trimethylenedioxy)- and 7,7-(ethylenedioxy)-1,3,5-cycloheptatriene (1c-f) form 1:1 cycloadducts of different structure. For the cycloadducts from 1d, e and cycloheptatriene itself, 13C and 1H NMR spectra establish a structure formally derived from the norcaradiene valence tautomer (2a, d, e) by [4 + 2] cycloaddition (NCD-type, 4). 1c, f and tropone, on the other hand, undergo [4 + 2] cycloaddition at C-1/C-4 of the cycloheptatriene skeleton, yielding adducts of the CHT-type 3.
    Notes: 4-Phenyl-1,2,4-triazolin-3,5-dion (PTAD) bildet mit 7,7-Difluor-, 7,7-Dimethoxy-, 7,7-(Trimethylendioxy)- und 7,7-(Ethylendioxy)-1,3,5-cycloheptatrien (1c-f) 1:1-Cycloaddukte unterschiedlicher Struktur. Nach 13C- und 1H-NMR-Spektren besitzen die Cycloaddukte aus 1d, e und dem unsubstituierten Cycloheptatrien eine Struktur, die sich vom Norcaradien-Valenztautomeren (2a, d, e) durch [4 + 2]-Cycloaddition ableiten läßt (NCD-Typ, 4). Bei 1c, f und beim Tropon dagegen erfolgt [4 + 2]-Cycloaddition an C-1/C-4 des Cycloheptatrien-Skeletts: es entstehen Addukte vom CHT-Typ 3.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821151019
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  • 10
    Electronic Resource
    Electronic Resource
    Riburon- und Lyxuronpurinnucleosid-Derivate - Synthese, Trennung und Struktursicherung der verschiedenen Verknüpfungsisomeren (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2891-2915 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Riburonic and Lyxuronic Purine Nucleoside Derivatives - Synthesis, Separation, and Structural Elucidation of the Various Linkage Isomers1)By direct, molten state condensation of riburonic (1) and lyxuronic acid derivatives (14) with silylated purine (2a), chloro- and amino-purines (2b-g), respectively, N-7 and N-9 purinyl nucleosides with both α- and β-configuration were obtained in mixtures of varying composition, depending, inter alia, on the structure of the carboxyl function; the linkage isomers were separated quantitatively by medium pressure chromatography on silica gel columns of high separation potential. To test the known criteria for structural assignment on the wide range of glycosidic isomers thus available, UV, 1H-NMR and 13C-NMR spectra were recorded under standardized conditions for all derivatives. Assignment of purine regiochemistry from UV data proved not reliable; it can be established, though, unequivocally from the 13C-NMR data of the aglycone. The configuration at the anomeric center of the sugar moiety, on the other hand, is readily determined from the furanoside 13C-shifts of the 2′,3′-O-isopropylidenated nucleosides.
    Notes: Durch Schmelzkondensation von Riburonsäure- (1) und Lyxuronsäure-Derivaten (14) mit silyliertem Purin (2a) bzw. silylierten Chlor- und Aminopurinen (2b-g) wurden - u. a. in Abhängigkeit von der Struktur der Carboxylfunktion - verschiedene Anteile an N-7- und N-9-verknüpften α- und β-konfigurierten Purinnucleosiden erhalten; die Verknüpfungsisomeren wurden durch Mitteldruckchromatographie an leistungsfähigen Trennsäulen quantitativ aufgetrennt. Um die bisherigen Kriterien für die Strukturzuordnung daran zu prüfen, wurden von allen Derivaten unter standardisierten Bedingungen UV-, 1H-NMR- und 13C-NMR-Spektren aufgenommen. Die Regiochemie am Purin war zwar nicht zuverlässig aus UV-Daten, jedoch eindeutig aus den 13C-NMR-Daten des Aglycons zu ermitteln; die Konfiguration am anomeren Zentrum des Zuckers andererseits ließ sich aus den Furanosid-13C-Verschiebungen der 2′,3′-O-isopropyliden-geschützten Nucleoside sicher bestimmen.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801130908
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