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  • 1
    Electronic Resource
    Electronic Resource
    Aromatization of hydrocarbons by oxidative dehydrogenation catalyzed by the mixed addenda heteropoly acid H5PMo10V2O40 (1989)
    s.l. : American Chemical Society
    The @journal of organic chemistry 54 (1989), S. 4607-4610 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00280a029
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  • 2
    Electronic Resource
    Electronic Resource
    Anwendungen der Phasentransfer-Katalyse, 15. Phasentransfer-katalytische Herstellung von Kohlensäureestern ohne Verwendung von Phosgen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1210-1215 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Applications of Phase Transfer Catalysis, 15. Phase Transfer Catalytic Preparation of Carbonic Esters Without the Use of PhosgeneCarbonic esters can be prepared in a phase-transfer catalytic reaction from primary alkyl halides and a mixture of dry potassium hydrogen carbonate and dry potassium carbonate in non-polar solvents. The conversion is ineffective inthe absence of hydrogen carbonate and catalyst.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140343
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  • 3
    Electronic Resource
    Electronic Resource
    Anwendungen der Phasentransfer-Katalyse, 6: Nebenreaktionen der Dihalogencarbenerzeugung aus Haloform/Natronlauge/Katalysator (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 3873-3878 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Applications of Phase Transfer Catalysis, 6: Side, Reactions of Dihalocarbene Generations from Haloform/Sodiumhydroxide/CatalystAppreciable amounts of side products are formed by reaction with the haloform in the phase-transfer catalytic dihalocarbene generation and addition to unreactive olefins. CX4, CH2X2, C2X4, and C2HX5 (X = Cl, Br) are formed along with a polymer.  -  In the dibromocarbene process with sterically hindered or electron poor olefins, side products of a radical addition of CBr4, CHBr3 or even Br2 (from CBr4) across the double bond are also found, if the reaction is conducted in the presence of air and light.
    Notes: Bei der phasentransfer-katalytischen Dihalogencarbenaddition an reaktionsträge Olefine treten merkliche Mengen von Nebenprodukten auf, die durch Angriff auf das Haloform entstehen: CX4, CH2X2, C2X4 und C2HX5 (X = Cl, Br), daneben ein Polymeres.  -  Speziell bei der Dibromcarbenreaktion mit sterisch abgeschirmten und elektronenarmen Alkenen in Gegenwart von Luft und Licht werden radikalische Seitenreaktionen beobachtet, bei denen CBr4, CHBr3 oder sogar Br2 (aus CBr4) an die Doppelbindung addiert werden.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781111213
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  • 4
    Electronic Resource
    Electronic Resource
    Ein einfaches Verfahren zur vollständigen Methylierung der α-Positionen einiger Ketone (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 263-264 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Convenient Procedure for Complete Methylation of the α-Positions of Some Ketones2,2,6,6-Tetramethylcyclohexanone (2a), Pivalophenone (4a), and other complete methylated ketones can be prepared by a simple procedure. Therefore the ketone was treated with methyl iodide and powdered KOH in the presence of catalytical amounts of [18]crown-6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870318
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  • 5
    Electronic Resource
    Electronic Resource
    Mehrfachaddukte von Dihalogencarbenen an Polyolefine und Versuche zur gezielten partiellen Enthalogenierung (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 181-193 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyaddukts of Dihalocarbenes to Polyolefins and Experiments on Directed Partial DehalogenationPhase transfer catalysis permits the addition of up to 2 :CHal2 to pyrene, up to 3 :CHal2 to bullvalene, and up to 4 :CHal2 to cyclooctatetraene, However, the yields of higher adducts are low. Several reducing agents are used for partial dehalogenation of cyclooctatetraene adducts. Removal of several endo-bromine atoms in one step is possible most efficiently with tributyl tin hydride, but zinc/DMF shows high selectivity in some cases too. Removal of several endo-bromine atoms is achieved by halogen metal exchange at low temperature and subsequent methanolysis. In the case of the bisadduct 9b, there is a narrow temperature range in which alternative ring enlargement and immediate valence tautomerization to naphthalene can be avoided.
    Notes: Die Phasentransfer-Katalyse gestattet die Addition von bis zu 2 :CHal2 an Pyren, bis zu 3 :CHal2 an Bullvalen und bis zu 4 :CHal2 an Cyclooctatetraen. Jedoch sind die Ausbeuten niedrig. Verschiedene Reduktionsmittel wurden zur partiellen Enthalogenierung der Cyclooctatetraen-Addukte erprobt. Zur Entfernung mehrerer exo-Bromatome in einem Reaktionsschritt ist Tributylzinnhydrid am besten geeignet, aber auch Zink/DMF reagiert gelegentlich sehr selektiv. Die Entfernung mehrerer endo-Bromatome gelingt durch Halogen-Metall-Austausch bei tiefer Temperatur und anschließende Methanolyse. Beim Bisaddukt 9b gibt es einen engen Temperaturbereich, in dem die alternative Ringerweiterung und sofortige Valenztautomerisierung zu Naphtha-lin vermieden werden kann.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919790206
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  • 6
    Electronic Resource
    Electronic Resource
    Extraktion nucleophiler und nicht nucleophiler Basen in unpolare Medien unter Bedingungen der Phasentransfer-Katalyse (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 28-32 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Extraction of Nucleophilic and Non-nucleophilic Bases into Non-polar Media under the Conditions of Phase Transfer CatalysisOH⊖ ions can be extracted by NR4Hal into non-polar media only to a minor extent, even if a more than hundredfold excess of sodium hydroxide in water is present. The anions of solid carbonates and alkali metal hydrides cannot be transferred into organic media. In the presence of acidic compounds H-Sub there are considerable concentrations of ion pairs [catalyst cation⊕] [Sub⊖] in organic media. Therefore, deprotonation of H-Sub must occur on the phase boundary of the solid salts.
    Notes: Selbst in Gegenwart eines mehrhundertfach molaren Überschusses an Natronlauge können OH⊖-Ionen aus wäßriger Phase nur in untergeordnetem Maße durch NR4Hal in unpolare Lösungsmittel transportiert werden. Die Anionen fester Carbonate und Alkalimetallhydride sind durch NR4Hal nicht in organische Medien überführbar. In Gegenwart acider Verbindungen H-Sub befinden sich merkliche Konzentrationen von Ionenpaaren [Katalysator-Kation⊕] [Sub⊖] in organischen Medien. Die Deprotonierung von H-Sub läuft demnach an der Grenzfläche der Salze ab.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119810106
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  • 7
    Electronic Resource
    Electronic Resource
    Reaktionen mit Dimethylcarbonat, 2. N-Methylierung von Imidazol und Derivaten (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 77-79 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions with Dimethyl Carbonate, 2. - N-Methylation of Imidazole and DerivativesThe use of dimethyl carbonate as methylating agent for imidazole derivatives is demonstrated by selected examples. The comparison of the toxicological values of dimethyl carbonate and dimethyl sulfate should inspire to replace the highly toxic dimethyl sulfate by dimethyl carbonate.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870114
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  • 8
    Electronic Resource
    Electronic Resource
    Anwendungen der Phasentransfer-Katalyse, 14. Darstellung von Alkinen aus Alkylhalogeniden mit festem Kalium-tert-butylat und Kronenether (1980)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 1-13 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Applications of Phase Transfer Catalysis, 141).  -  Preparation of Alkynes from Alkyl Halides with Solid Potassium tert-Butoxide and Crown EtherPreparatively very simple and mild HX eliminations with solid potassium tert-butoxide in petroleum ether in the presence of catalytic amounts of [18]crown-6 are described. 1,2-Dihalides (from alkenes) and 1,1-dihalides (from aldehydes) yield 1-alkynes; internal geminal dihalides (from symmetric ketones) give internal alkynes in excellent yields. 2,2-Dihalides (from methyl ketones) yield homogeneous 1-alkynes only if the 3-position is blocked. (E)-Haloalkenes lead also to alkynes in a syn-elimination process.
    Notes: Präparativ einfach und milde verläuft die HX-Eliminierung mit festem Kalium-tert-butylat in Petrolether bei Gegenwart katalytischer Mengen [18]Krone-6. 1,2-Dihalogenide (aus Alkenen) sowie 1,1-Dihalogenide (aus Aldehyden) liefern 1-Alkine, mittelständig geminale Dihalogenide (aus symmetrischen Ketonen) liefern mittelständige Alkine in sehr guten Ausbeuten. 2,2-Dihalogenide (aus Methylketonen) geben nur dann völlig einheitliche 1-Alkine, wenn die 3-Stellung blockiert ist. (E)-Halogenalkene führen unter syn-Eliminierung ebenfalls zu Alkinen.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198019800102
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  • 9
    Electronic Resource
    Electronic Resource
    Herstellung und Reaktionen einiger Umpolungsreagenzien durch Phasentransfer-Katalyse (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1589-1601 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Reactions of Some Reagents for Umpolung under Phase-transfer CatalysisThioacetals 4a - h are used as reagents for umpolung. They can be prepared in high yields from inexpensive starting materials under phase-transfer catalysis (PTC). H/D-exchange reactions of thioacetals under PTC-conditions are described. Ethyl 1,3-dithiane-2-carboxylate (4a) served as a model compound in order to demonstrate possibilities and limitations of PTC-deprotonation and subsequent reaction with electrophiles compared with other procedures.
    Notes: Die als Umpolungsreagenzien verwendeten Thioacetale 4a - h werden durch Phasentransfer-Katalyse (PTC) in hohen Ausbeuten mit billigen Ausgangsmaterialien zugänglich. Der H/D-Austausch an Thioacetalen unter PTC-Bedingungen wird beschrieben. An 1,3-Dithian-2-carbonsäure-ethylester (4a) werden Möglichkeiten und Grenzen der PTC-Deprotonierung und der anschließenden Reaktion mit Elektrophilen aufgezeigt und mit herkömmlichen Methoden verglichen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820902
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