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  • 11
    ISSN: 0009-2940
    Schlagwort(e): Benzo[c]thiophenes ; preparation by the S-oxide route ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Structure and Reactivity of Isoannullated Heterocyclic Systems with 4n;-π and (4n + 2)-π Electrons, XVIII. - Benzo[c]thiophenes with Symmetric Structure: Modified and Optimized Preparation by the S-Oxide RouteBenzo[c]thiophenes (15) with symmetric structure have been prepared efficiently from 1,3-dihydrobenzo[c]thiophene 2-oxides (9) by reaction with aluminium oxide, by O-acylation with trifluoroacetic anhydride, or O-alkylation with methyl trifluoromethanesulfonate. The aromatization of the S-oxides 9 is achieved by O-functionalization, subsequent elimination, and consecutive deprotonation.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 183-189 
    ISSN: 0009-2940
    Schlagwort(e): 2H-Isoindoles, 2-alkyl-, reactions with C=C dienophiles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Studies on the Chemistry of Isoindoles and Isoindolenines, XXXIX.  -  Reactions of 2-Alkyl-4,5,6,7-Rn-2H-isoindoles (Rn=tetramethyl, tetrachloro) with Activated C=C DienophilesSubstituted 2H-Isoindoles 2 react with maleic imides in absolute ether. Cycloaddition in 1,3-position leads to the formation of 1:1 adducts. The ratio between endo isomers 4 and exo isomers 5 depends on the substituents and the solvents. In the case of steric hindrance the Diels-Alder addition can be induced by Lewis acids. In the presence of oxygen-substituted 4,5,6,7-tetrachloro-2-methylisoindolin-1-ones 7 are formed as minor products.
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 1919-1930 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Pentacarbonylchromium Complexes of 1H-IsoindolesThe 1H-isoindoles 1e-k are converted into the pentacarbonylchromium complexes 4e-k by means of ligand exchange reactions with pentacarbonyl(η2-cis-cyclooctene)chromium (3). Likewise, the 2H-isoindoles (2a-d) which are able to undergo tautomerism are complexed in the 1H-form 4a-d. This reaction allows, for the first time, to isolate even unsubstituted 1H-isoindole (1a) from the equilibrium with 2H-isoindole (2a) as a stable derivative 4a. The structure 4 of the pentacarbonyl(η1-1H-isoindole)chromium complexes is elucidated from the analytical and spectroscopic data (IR, 1H and 13C NMR, MS) as confirmed by means of an X-ray structure analysis of the 3-ethoxy-1H-isoindole complex 4e.
    Notizen: Die 1H-Isoindole 1e-k werden durch Ligandenaustausch mit Pentacarbonyl(η2-cis-cycloocten)chrom (3) in die Pentacarbonylchrom-Komplexe 4e-k übergeführt; tautomeriefähige 2H-Isoindol (2a-d) werden ebenfalls in der 1H-Form komplexiert (4a-d). Diese Reaktion erlaubt erstmals, auch das unsubstituierte 1H-Isoindol (1a) aus dem Gleichgewicht mit 2H-Isoindol (2a) in Form eines stabilen Derivats 4a zu isolieren. Die Struktur 4 der Pentacarbonyl(η1-1H-isoindol)chrom-Komplexe ergibt sich aus den analytischen und spektroskopischen Daten (IR, 1H- und 13C-NMR, MS) und wird durch eine Röntgenstrukturanalyse des 3-Ethoxy-1H-isoindol-Komplexes 4e bestätigt.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1203-1205 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 2,3-Dihydro-2,3-bismethylenebenzo[b]thiophene, a Reactive Annellated DieneThe cis configurated annellated diene 4 is generated in solution by the reaction of the easily accessible 2,3-bis(bromomethyl)-benzo[b]thiophene (3) with sodium iodide. In the presence of CC or NN dienophiles [4+2] cycloaddition reaction take place and lead to 5, 6, 11, and 12 with acceptable yields. This annellation method is useful for the synthesis of polycyclic compounds.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 337-342 
    ISSN: 0009-2940
    Schlagwort(e): Isoindoles ; Substitution with electrophiles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Studies on the Chemistry of Isoindoles and Isoindolenines, XXXIV. - 2-tert-Butyl-2H-isoindole - Substitution Reactions with ElectrophilesThe thermally remarkable stable o-quinonoid hetarene 2 reacts with electrophiles in α-position to the heteroatom and can be protonated and alkylated. The reactions with arenediazonium tetrafluoroborates lead to the formation of the substitution products 10.
    Notizen: Das thermisch bemerkenswert stabile o-chinoide Hetaren 2 reagiert mit Elektrophilen in α-Stellung zum Heteroatom und ist protonierbar und alkylierbar. Bei Reaktionen mit Arendiazonium-tetrafluoroboraten entstehen die Substitutionsprodukte 10.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 381-390 
    ISSN: 0009-2940
    Schlagwort(e): o-Quinoid hetarenes / Isoindoles, cycloaddition reactions with / Dienophiles, CC ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Studies on the Chemistry of Isoindoles and Isoindolenines, XXXVI - Reactions of 2-Alkyl-2H-isoindoles with Maleic Imides2-Alkyl-2H-isoindoles 2 react with maleic imides 4 exclusively in position 1 and 3 by cycloaddition to form Diels-Alder adducts. The transformation of the endo isomers 6 into the thermodynamically more stable exo isomers 7 depends on the dienophile. The cycloaddition is useful for analytical detection of o-quinoid hetarenes 2 and for the synthesis of 7-azabicyclo[2.2.1]heptenes.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 1771-1784 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Dipole relaxation dielectric loss behavior of a fiberglass-epoxy composite has been studied as a function of moisture uptake. A single widely distributed loss peak, centered at -16°C for 10 kHz measurement, is observed in the dry composite. Very low moisture concentrations (〈0.1%) interact with the composite, through either dipole pairing or by inducing chemical changes, to decrease loss intensity. At moisture concentrations from 0.1 to 1.4%, loss peak intensity generally increases with moisture uptake. Over this moisture concentration range water dipoles presumably relax in phase with the epoxy segments or side groups upon which they adsorb. Arrhenius relaxation activation energy decreases, and improved loss peak definition at increasing moisture concentrations is interpreted as indicating resin plasticization by adsorbed moisture. At moisture concentrations above 1.4%, the appearance of a second loss peak suggests formation of a new colloidal or weakly adsorbed moisture phase, as well as the saturation of primary adsorption sites.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 15 (1993), S. 147-176 
    ISSN: 0887-3585
    Schlagwort(e): X-ray crystallography ; pAR5 mutant ; allosteric enzyme ; ligand-induced negative cooperativity ; alternative amino acid conformations ; coordinate error ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The X-ray crystal structure of CTP-ligated T state aspartate transcarbamoylase has been refined to an R factor of 0.182 at 2.5 Å resolution using the computer program X-PLOR. The structure contains 81 sites for solvent and has rms deviations from ideality in bond lengths and bond angles of 0.018 Å and 3.722°, respectively. The cytosine base of CTP interacts with the main chain carbonyl oxygens of rTyr-89 and rIle-12, the main chain NH of rIle-12, and the amino group of rLys-60. The ribose hydroxyls form polar contacts with the amino group of rLys-60, a carboxylate oxygen of rAsp-19, and the main chain carbonyl oxygen of rVal-9. The phosphate oxygens of CTP interact with the amino group of rLys-94, the hydroxyl of rThr-82, and an imidazole nitrogen of rHis-20. Recent mutagenesis experiments evaluated in parallel with the structure reported here indicate that alterations in the hydrogen bonding environment of the side chain of rAsn-111 may be responsible for the homotropic behavior of the pAR5 mutant of ATCase. The location of the first seven residues of the regulatory chain has been identified for the first time in a refined ATCase crystal structure, and the proximity of this portion of the regulatory chain to the allosteric site suggests a potential role for these residues in nucleotide binding to the enzyme. Finally, a series of amino acid side chain rearrangements leading from the R1 CTP allosteric to the R6 CTP allosteric site has been identified which may constitute the molecular mechanism of distinct CTP binding sites on ATCase. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 131-140 
    ISSN: 0887-6134
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Mixtures of both synthetic and naturally occurring (human plasma) cholesteryl esters have been examined by capillary gas chromatography/mass spectrometry (GC/MS). A magnetic sector mass spectrometer was used and a variety of ionization modes were assessed with a view to obtaining structural information on intact cholesteryl esters. By employing ammonia as reagent gas, with negative ion scanning, spectra were produced from which the nature of steryl and fatty acyl moieties could be readily deduced. Analyses were performed at an ion source temperature of 300°C in order to maintain the integrity of the gas chromatographic profile. The technique described is of general use for the GC/MS analysis of steryl esters, particularly in conjunction with magnetic sector instruments.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 17 (1993), S. 329-334 
    ISSN: 0887-3585
    Schlagwort(e): bacterial toxins ; superantigens ; X-ray crystallography ; crystallization ; Staphylococcus aureus ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Native toxic shock syndrom toxin 1 (TSST-1) purified from Staphylococcus aurius has been crystallized in four different forms. The highest resolution data (2.05 Å) was collected from orthorhombic crystals belonging to the space group C2221. The unit cell dimension are a = 108.7 Å, b = 177.5 Å, c = 97.6 Å. Rotation function analysis of this from indicates that there is trimer of toxin molecules in the asymmetric unit with a local 3-fold axis parallel to the crystallographic c axis. Crystals of a double mutant of TSST-1 have been grown which has a single molecule in the asymmetric unit and diffract to 1.9 Å. The space group is P21 with unit cell parameters of a = 44.4 Å, b = 34.0 Å, c = 55.2 Å, β = 93.0°. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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