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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 91 (1969), S. 1540-1542 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Polyalkylthio- and Polyarylthiomethanes, -ethanes and -ethylenes from Metalated OrthotrithioformatesAliphatic, cycloaliphatic, and aromatic thioles are converted to orthotrithioesters in good yields by treatment with trimethyl orthoformate in the presence of Lewis acids; open chain, monocyclic and bicyclic derivatives 4a-s and 8 are prepared. Methods for the unambiguous synthesis of tristhiomethanes with two different RS-groups are described. Metalated orthotrithioformates 1 are obtained form 4 and n-butyllithium in THF at -70° as shown by quantitative isolation of the 1.1.1-tristhioethanes 5 after reaction with iodomethane. The organometallic compounds 1 decompose to give tetrakisthioethylenes 6. Decomposition takes place, thermally“ between -50 and -20° in the case of open chain alkyl derivatives 1 while the aryl analogs must be, decomposed“ with cyclohexene epoxide. The tetrakisthiomethanes 7, 9, 17, 18 and 19 are prepared form metalated formaldehyde dithioacetals or orthotrithioformates and disulfides.
    Notes: Aliphatische, cycloaliphatische und aromatische Thiole liefern in Gegenwart von Lewis-Säure mit Orthoameisensäure-trimethylester in guten Ausbeuten die offenkettigen, monocyclischen und bicyclischen Trithioester 4a-s und 8. Methoden zur gezielten Herstellung von Derivaten mit zwei verschiedenen RS-Gruppen werden beschrieben. Die Orthotrithioester werden bei -70° in THF durch Butyllithium quantitativ zu 1 metalliert. Aus den Metallderivaten 1 und Methyljodid entstehen die 1.1.1-Tris-mercapto-äthane 5. Zerfall von 1 liefert die Tetrakis-mercapto-äthylene 6; die alkylsubstituierten Verbindungen 1 zerfallen schon bei Temperaturen zwischen -50 und -20°; um Tetrakis-arylmercapto-äthylene herzustellen, muß man die entsprechenden Verbindungen 1 mit Cyclohexenoxid, zersetzen“. Thiolierungen von metallierten Formaldehyd-dithioacetalen und Orthotrithioameisensäureestern mit Disulfiden führen zu den Tetrakis-mercapto-methanen 7, 9, 17, 18 und 19.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: E.S.R. Spectroscopic Proof for the C-C Dissociation of Hexakis(organylthio)ethanes and the S-C Dissociation of Tetrakis(organylthio)methanes. Tris(organylthio)methyl RadicalsUnstable tris(arylthio)methyls of type 2 are generated by heating hexakis(arylthio)ethanes such as 1 (100°) and tetrakis(arylthio)methanes such as 3 (140°). The identity of these radicals is confirmed by e.s.r. spectroscopy. The singlet signal observed for 2 is split to a 43.7 Gauss doublet in the 13C-labelled radical; partial replacement of the sulfur atoms by 33S causes the expected HFS-splitting by three sulfur nuclei (a(33S) == 4.2 Gauss). In the pyrolysis of the „mixed“ thioorthocarbonate 7 and of thioorthooxalate 9 the methylthiobis(phenylthio)-methyl (8) is observed as a quartet with a(CH3) == 2.1 Gauss. According to these data, the radical electron density is highest at the central carbon atom of 2. The easy homolysis of the bonds in 1 and 3 is therefore a consequence of steric hindrance in the dimer and in the methane rather than of resonance stabilization in the radical. This conclusion is substantiated by the fact that the ethanes bearing o-tolylthio or cyclohexylthio groups dissociate at lower temperatures.
    Notes: Beim Erhitzen von Hexakis(arylthio)äthanen wie 1 (100°) und von Tetrakis(arylthio)methanen wie 3 (140°) treten instabile Tris(arylthio)methyle vom Typ 2 auf, deren Identität ESR-spektroskopisch gesichert wurde. Das Singulett-Signal von 2 wird nach 13C-Markierung am Methylkohlenstoff in ein Dublett (43.7-Gauss) aufgespalten; im Spektrum des 33S-markierten 2 treten die erwarteten Aufspaltungen durch drei Schwefelkerne ein (a(33S) == 4.2 Gauss). Bei der Pyrolyse des „gemischten“ Orthokohlensäureesters 7 bzw. des entsprechenden Äthans 9 beobachtet man das Signal des Methylthiobis(phenylthio)methyls (8), das eine Methyl-Quartettaufspaltung a(CH3) von 2.1 Gauss zeigt. Nach den gemessenen Parametern ist das ungepaarte Elektron überwiegend am zentralen Kohlenstoff von 2 lokalisiert. Für die leichte Homolyse der Bindungen in 1 und 3 ist somit sterische Hinderung im nicht dissoziierten Molekül und nicht Mesomerie-Stabilisierung der Radikale verantwortlich zu machen. Hierfür sprechen auch die Ergebnisse an entsprechenden Äthanen mit sterisch anspruchsvolleren Substituenten.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 3892-3904 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Simple Preparation of Hexakis(organylthio)ethanes Pyrolysis of Hexakis(arylthio)ethanes Indications of a C—C DissociationCoupling of tris(arylthio)- and tris(alkylthio)methyllithium derivatives with iodine leads to hexakis(organylthio)ethanes 7-10. In the pyrolysis of the phenyl derivative 7a above 100° with or without solvents decomposition takes place to give the following products: diphenyl disulfide (11a), phenyl dithiobenzoate (12a), tris(phenylthio)methane (13a), tetrakis(phenylthio)ethylene (14a), and tetrakis(phenylthio)methane (15a). The methanes 15 yield the same types of compounds 11-14 when heated at temperatures ranging from 165 to 230°. Formation of the ethylene 14a from the ethane 7a is proved by 13C-labelling to be preceded by C-C-bond dissociation of the latter compound. All results are readily explained by assuming that the initial reaction step is the homolysis of the C-C bond in the ethanes 7 and of the ArS-C bond in the methanes 15 to give tris(arylthio)methyls.
    Notes: Kupplung von Tris(arylthio)- und Tris(alkylthio)methyllithium-Verbindungen 6 mit Jod führt zu Hexakis(organylthio)äthanen 7-10. Beim Erhitzen des Phenylderivates 7a tritt oberhalb von 100° in verschiedenen Lösungsmitteln Zersetzung zu Diphenyldisulfid (11a), Dithiobenzoesäure-phenylester (12a), Tris(phenylthio)methan (13a), Tetrakis(phenylthio)-äthylen (14a) und Tetrakis(phenylthio)methan (15a) ein. Auch 15a liefert bei höherer Temperatur diese Produkte. Durch 13C-Markierung wird bewiesen, daß der Bildung des Äthylens 14a aus dem Äthan 7a eine C-C-Dissoziation vorausgeht. Alle Befunde lassen sich damit erklären, daß die Äthane 7 unter C-C-, die Methane 15 unter ArS-C-Dissoziation zunächst Tris(arylthio)methyl-Radikale liefern.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 367-379 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Lithio-1,3,5-trithianes Generation in Solution, Reactions with Electrophiles, and Use in Nucleophilic Acylation1,3,5-Trithiane and 2-mono- as well as 2,4,6-trisubstituted trithianes are shown to be metallated by n-butyllithium in THF. Reaction of the lithio derivatives thus obtained with electrophiles leads to more highly substituted trithianes which in some cases can be isolated in a pure form. The n.m.r. spectra of the products at room temperature are described. Mercury(II)-assisted solvolysis of alkyltrithianes „liberates“ the most highly substituted carbon with formation of carbonyl compounds or their O-acetals. This completes a sequence of reactions which suggests use of lithiotrithianes as reagents for nucleophilic acylation. Advantages and disadvantages of this procedure compared to the dithiane method are discussed.
    Notes: 1,3,5-Trithian selbst sowie 2-mono- und 2,4,6- trisubstituierte Trithiane lassen sich mit n-Butyllithium in Tetrahydrofuran metallieren. Umsetzung der Lithiumderivate mit Elektrophilen führt zu höher substituierten Trithianen, die teilweise in reiner Form isoliert werden können. Die NMR-Spektren der erhaltenen Produkte bei Raumtemperatur werden beschrieben. Quecksilber(II)-assistierte Solvolyse von alkylierten Trithianen führt zu Carbonyl-verbindungen oder deren O-Acetalen unter „Herauslösung“ des höchstsubstituierten C-Atoms, was die Verwendung von Lithiotrithianen als nucleophile Acylierungsmittel ermöglicht. Vor- und Nachteile gegenüber der Dithian-Methode werden diskutiert.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 314-321 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mono- and Bis(pheyltelluro)methyllithiumSolutions of the title compounds are readily prepared from bis(phenyltelluro)methane (7): the monosubstituted one by transmetallative C6H5Te/Li-exchange with alkyllithium, the disubstituted one by direct metalation with lithium diisopropylamide. This was proved in both cases by deuterolysis and derivatization with electrophiles. The new tellurium derivatives are compared with the sulfur and selenium analogues.
    Notes: Lösungen der Titelverbindungen lassen sich aus Bis(phenyltelluro)methan (7) leicht darstellen, das monosubstituierte Li-Derivat durch C6H5Te/Li-Austausch mit Alkyllithium, das disubstituierte durch direkte Metallierung mit Lithium-diisopropylamid. In beiden Fällen wurde dies durch Deuterolyse und Umsetzung mit Elektrophilen bewiesen. Die neuen Tellurderivate werden mit den Schwefel- und Selen-Isologen verglichen.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Steric Course of the Reaction of Enamines Derived from Open-Chain Aldehydes and Ketones with Nitro-olefins Yielding 2,3-Disubstituted 4-NitroketonesThe relative configuration of the nitro-ketone 12 obtained by the title reaction has been proved by a Baeyer-Villiger degradation and subsequent reduction to the amino-alcohol (±)-(u)-20, the relative configuration of which is identical with a sample prepared from 2-methyl-3-hydroxybutyrate of known configuration (Scheme 1). The stereochemical course of the title reaction is thus as predicted by our topological rule. It is assumed that the other nitro-ketones 13-18 described here are also formed by (lk)-combination of the trigonal centers of the educts (diastereoselectivity 〉 90%, see Formulae and Fig. 1). It is not possible to reverse this relative topicity by employing (Z)- instead of (E)-components of the starting materials, due to the reversibility of the primary step of these Michael additions (Schemes 2 and 3, and Fig. 2).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 1822-1827 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Anion-Selectivity of Distannyl Derivatives in MembranesA series of distannyl derivatives (2,2-bis(trimethylstannyl)-1,3-dithiane, 2,2-bis(tributylstannyl)-1,3-dithiane, hexamethyldistannane, hexabutyldistannane, hexaphenyldistannane, bis(triphenylstannyl)sulfide, o-bis(trimethylstannyl)benzene) has been studied in view of their applicability as anion-selective ionophores in solvent polymeric membranes. None of these compounds induces significant changes in the anion-selectivity pattern as compared with the membranes containing no organotin compound. Representatives with tributylstannyl groups, however, undergo chemical reactions leading to highly active anion ionophores of the type Bu3SnX, several of which (e.g. Bu3SnCl and Bu3SnOH) may be present in equilibrium in the membrane phase depending on the measuring conditions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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