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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 98 (1965), S. 3251-3254 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclo-bis-[ω-amino-dodecansäure]-amid wird dargestellt und charakterisiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2489-2498 
    ISSN: 0009-2940
    Keywords: (+)-Menthyllithium, stereoselective metallation with ; Prochiral sulfoxides, enantio- and diastereoselective α-deprotonation of ; 2-Bornyllithium, content of isobornyllithium in ; Racemization, mechanism by intermolecular transmetallation ; e.e., temperature dependence of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantio- and Diastereoselective α-Metallation of Prochiral Sulfoxides by (+)-MenthyllithiumSix out of ten prochiral dialkyl sulfoxides 3 with diastereotopic α methylene protons were stereoselectively metallated by (+)-menthyllithium (11) to yield two diastereomeric pairs of enriched enantiomers 29 after the reaction with benzophenone. The maximum e.e. was 40%. Dicyclohexyl sulfoxide (3c) was deprotonated enantioselectively with an e.e. of 30%. 2-Bornyllithium (21) was unsuccessful as a chiral base and was shown for the first time to contain 4% of isobornyllithium (22). The reactions were performed in pentane at - 80°C; in diethyl ether and THF the e.e.'s were only slightly higher, and at higher temperatures the selectivity was rapidly decreasing. It was shown that racemization takes place by an intermolecular transmetallation reaction. The structure of 29f [n = 3] was elucidated by an X-ray analysis.
    Additional Material: 6 Ill.
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  • 3
    ISSN: 1434-193X
    Keywords: Triplet recombination ; Electron transfer ; Radical ions ; Photochemistry ; Terpenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The triphenypyrylium tetrafluoroborate (TPT)-sensitized reactions of several terpene donor molecules, including sabinene (1), α-phellandrene (4), α-terpinene (5) and γ-terpinene (6) give rise to significantly different products than reactions induced by other electron-transfer sensitizers, such as 1,4-dicyanobenzene (DCB). The divergent reactions require decidedly different key intermediates; the products obtained with TPT can be explained by dissociative recombination of the intermediate radical-radical cation pair in the triplet state, generating donor-derived biradicals.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1434-193X
    Keywords: Zeolites ; Radical ions ; Ring opening ; Electron transfer ; Oxidations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Incorporation of trans-1,2-diphenylcyclopropane (1) and its 3,3-D2-isotopomer into the channels of a redox-active pentasil zeolite (Na-ZSM-5) resulted in the formation of exo,exo-1,3-diphenylallyl radical (2•) and its 2-D1 isotopomer, respectively. This conversion requires oxidation, ring opening, and deprotonation, in an unspecified sequence. The allyl radical 2• is also formed upon incorporation of trans-1,3-diphenylpropene (3). A comparison with the solution photochemistry, in the presence or absence of added base, shows the conversion of 1 into 2• to be a zeolite-specific reaction. Incorporation of arylcyclopropanes 9 (R = H, OCH3) into ZSM-5 generated trans-propenylbenzene radical cations 10•+ (R = H, OCH3); the 2,2-D2 isotopomer of 9 (R = OCH3) gave rise to three different isotopomers of 10•+ (R = OCH3).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-193X
    Keywords: Zeolites ; Electron transfer ; Proton transfer ; Radical ions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Incorporation of N,N′-diphenylhydrazine into HZSM-5 led to the formation of azobenzene and aniline (70-80 mol-% mass balance). The formation of azobenzene can be followed by the appearance in diffuse reflectance UV/Vis spectroscopy of a characteristic band (λmax = 420 nm). IR spectra of the extracted solids indicate that some aniline is retained in the zeolite, probably due to acid-base interaction with active sites. The products are rationalized by two competing mechanisms: the formation of azobenzene by electron transfer to an oxidizing site, the generation of aniline by proton transfer from a Brønsted acid site. A long-wavelength diffuse-reflectance band (λmax = 800 nm) in the initial stages of the reaction supports the intermediacy of a radical cation. These results show that acid zeolites can exhibit a dual behavior against basic substrates with low oxidation potential, serving simultaneously as electron acceptor and Brønsted acid.
    Additional Material: 3 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 82 (1970), S. 181-181 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 83 (1971), S. 170-171 
    ISSN: 0044-8249
    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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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 55 (1983), S. 729-729 
    ISSN: 0009-286X
    Keywords: methylalkoholische Salzlösungen ; kernmagnetische Resonanzspektroskopie ; Mischungsenthalpien ; Dampfdrücke ; Dichten ; Fundamentalgleichung ; Absorptionswärmepumpe ; Arbeitsstoffe ; Experimente ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 65 (1993), S. 541-552 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Use of Polyelectrolytes in Mechanical Solids/Liquid Separation. This article shows how optimisation tasks for the dewatering of sludge can be solved by starting from studies of chemical structure and steric properties of polyelectrolytes and laboratory experiments based thereon with a trans-portable computer-aided flocculation and dewatering apparatus. The optimum polyelectrolyte dosage lies in the range of the critical concentration c* (viscosimetric measurements) of the dissolved polyelectrolytes. On optimisation of the flocculant regime for mechanical solids/liquid separation by combined addition of anionic and cationic polyelectrolytes (dual process), it is necessary to consider the overall system of sedimentation and filtration. In an industrial scale plant, the consumption of flocculant could be reduced by up to 10% compared to laboratory studies. At the same time, the dewatering behaviour could be improved by up to 60%, a shearing strength of the sludge in excess of 20 kN/m2 reliably established, and plant operating reliability achieved for changing sedimentation properties.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2069-2080 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 4-Amino-7-(β-D-arabinofuranosyl)pyrrolo[2,3-d]pyrimidine  -  the Synthesis of Ara Tubercidin by Phase Transfer Catalysis4-Chloro-2-methylthio-7H-pyrrolo[2,3-d]pyrimidine (6e) and 1-bromo-2,3,5-tri-O-benzyl-D-arabinofuranose (7) react in the presence of benzyltriethylammonium chloride as phase transfer catalyst to give the nucleoside derivatives 8/9a in 85% yield. The latter were separated chromatographically, and the ratio of the anomers was determined to 8:2 (β: α). 9a was converted into 9d by ammonolysis and the desulfurisation, yielding 9e, was accomplished with raney nickel. The benzyl protecting groups in 9e, are split off by catalytic hydrogenation, and crystalline 4-amino-7-(β-D-arabinofuranosyl)pyrrolo[2,3-d]pyrimidine (3) was obtained after ion exchange chromatography. 7-Deaza-Ara A (3) is in contrast to Ara-A (1) not deaminated by adenosine deaminase.
    Notes: Aus 4-Chlor-2-methylthio-7H-pyrrolo[2,3-d]pyrimidin (6e) und 1-Brom-2,3,5-tri-O-benzyl-D-arabinofuranose (7) können durch Phasentransferkatalyse mit Benzyltriethylammoniumchlorid die Nucleosidderivate 8/9a in 85proz. Ausbeute erhalten werden. Diese werden chromatographisch getrennt und deren Anomerenverhältnis (β: α) mit 8:2 bestimmt. Durch Ammonolyse von 9a entsteht 9d; Entschwefelung von 9d mit Raney-Nickel führt zu 9e, dessen Benzylschutzgruppen durch katalytische Hydrierung abgespalten werden. Nach Ionentauscherchromatographie erhält man kristallisiertes 4-Amino-7-(β-D-arabinofuranosyl)pyrrolo[2,3-d]pyrimidin (3), das im Gegensatz zum virostatisch aktiven Ara-A (1) durch Adenosin-Desaminase nicht desaminiert wird.
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