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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 117 (1995), S. 9180-9189 
    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: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Theoretical and Spectroscopical Investigations of Indigo Dyes, XII Heterocyclic Five-membered Ring Ketones from 1.4-Disubstituted 2-Butanones: 4.4-Dimethylpyrrolidin-3-one, 4.4-Dimethylthiolan-3-one and 4.4-Dimethylselenolan-3-oneUpon addition of one equivalent of base 4-amino-1-bromo-3.3-dimethylbutan-2-one hydrobromide (5a) and 1-amino-4-bromo-3.3-dimethylbutan-2-one hydrobromide (5b) undergo cyclization to yield 4.4-dimethylpyrrolidin-3-one hydrobromide (6a). 1-Bromo-3.3-dimethyl-4-p-tosyloxybutan-2-one (5c) and 1.4-dibromo-3.3-dimethylbutan-2-one (5d) react with sodium sulfide and sodium selenide to give 4.4-dimethylthiolan-3-one (6d) and 4.4-dimethyl-selenolan-3-one (6e).
    Notes: 1-Brom-4-amino-3.3-dimethyl-butanon-(2)-hydrobromid (5a) und 4-Brom-1-amino-3.3-dimethyl-butanon-(2)-hydrobromid (5b) liefern bei Zusatz eines Äquivalentes Base 4.4-Dimethyl-pyrrolidon-(3)-hydrobromid (6a). Die bei der Synthese von 5a und b erhaltenen Zwischenprodukte 1-Brom-4-p-toluolsulfonyloxy-3.3-dimethyl-butanon-(2) (5c) und 1.4-Dibrom-3.3-dimethyl-butanon-(2) (5d) können mit Natriumsulfid bzw. Natriumselenid zu 4.4-Dimethyl-thiolanon-(3) (6d) und 4.4-Dimethyl-selenolanon-(3) (6e) umgesetzt werden.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 929-936 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Theoretical and Spectroscopical Investigations of Indigo Dyes, XIV 1.4.5.8-Tetrasubstituted Octane-3.6-diones as Potential Precursers of Basic Chromophores of Indigo DyesThe 1.4.5.8-tetrasubstituted octane-3.6-diones 4a-c, needed for cyclization reactions to produce the leuco forms 5a-e of the basic chromophores of indigo dyes 3a-e, can be prepared by addition of bromine or chlorine to the 2.3-unsaturated 1.4-diketones 8 or 9. The additions do not proceed stereoselectively. The ratio of diastereoisomers markedly depends on the solvent used. 8 is obtained by the reaction of 9 with silver tosylate, 9 by catalytic decomposition of the diazoketone 7.
    Notes: Die für Ringschlußversuche zu den Leukoformen 5a-e der Indigo-Grundchromophor-systeme 3a-e benötigten 1.4.5.8-tetrasubstituierten Octandione-(3.6) 4a-c können durch Addition von Brom bzw. Chlor an die 2.3-ungesättigten 1.4-Diketone 8 bzw. 9 dargestellt werden. Die Additionen verlaufen nicht stereoselektiv. Das Diastereoisomerenverhältnis ist stark vom verwendeten Lösungsmittel abhängig. 8 wird durch Umsetzung von 9 mit Silber-tosylat, 9 durch katalytische Zersetzung des Diazoketons 7 erhalten.
    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: Polyspiranes, 7. Cascade Rearrangements, 2: From Polyspiranes to Polycycles - Sixfold 1,2-Shifts in Functionalized Pentaspiro[2.0.2.0.2.0.2.0.2.1]hexadecanesThe pentaspirohexadecanes 3a, b may be rearranged to 8a, b via 7a, b, which are potential precursors of the [6.4]coronane 1. 7a and 8a were benzoylated to give 7d and 8e, respectively, the molecular structures of which were determined by X-ray analysis. 7a, b and 8a, b adopt the all-cis-configuration. 7a and 7b contain axial hydroxyl groups. The overall rearrangements of 3a, b may thus be described in terms of sixfold 1,2-shifts with inversion at both the migration origins and termini.
    Notes: Die Pentaspirohexadecane 3a, b können über 7a, b in 8a, b umgelagert werden. 7a, b sind potentielle Vorläufer des [6.4]Coronans 1. 7a und 8a wurden zu 7d bzw. 8e benzoyliert, die Molekülstrukturen von 7d und 8e röntgenographisch bestimmt. 7a, b und 8a, b sind all-cis-konfiguriert, 7a und 7b enthalten die Hydroxylgruppe axial gebunden. Die Gesamtumlagerungen von 3a, b können demnach als sechsfache 1,2-Verschiebungen unter Inversion am jeweiligen Ausgangs- und Endpunkt der Umlagerung beschrieben werden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 1035-1046 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyspiranes, 4. Syntheses and Coupling Reactions of Vinylcyclopropanes and Vinylidenedicyclopropanes Halogenated in Allylic PositionsSyntheses and coupling reactions of the vinylcyclopropanes and vinylidenedicyclopropanes respectively, brominated in allylic positions, 4-7, are described. Upon treatment with magnesium in ether, 4 yields the dimers 16-18, 5 the dimer 20, and 7 the cyclodimer 9. Upon treatment with phenyllithium, 6 and 7 undergo cyclization to yield 25 and 8, respectively.
    Notes: Es werden Synthesen und Kupplungsreaktionen der allylständig bromierten Vinylcyclopropane bzw. Vinylidendicyclopropane 4-7 beschrieben. Bei Behandlung mit Magnesium in Ether liefert 4 die Dimeren 16-18, 5 das Dimere 20 sowie 7 das Cyclodimere 9. Unter Einwirkung von Phenyllithium cyclisieren 6 und 7 zu 25 bzw. 8.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Theoretical and Spectroscopical Investigations of Indigo Dyes, XIII Preparation and Properties of 4.4.4′.4′-Tetramethyl-3.3′-dioxo-2.2′-biselenolanylidene, a Compound Containing the Basic Chromophore of Selenoindigo4.4.4′.4′-Tetramethyl-3.3′-dioxo-2.2′-biselenolanylidene (6e) can be prepared by oxidative dimerization of 4.4-dimethylselenolan-3-one (5e). The parallelism of the chemical and spectroscopical properties of 6e and selenoindigo (2, X = Se) as well as the hypsochromic shift of the longest wavelength u.v. absorption upon extension of the central double bound system of 6e, which is typical for indigo dyes, show that 6e may be considered as the basic chromophore of selenoindigo.
    Notes: 3.3′-Dioxo-4.4.4′.4′-tetramethyl-2.2′-biselenolanyliden (6e) kann durch oxydative Dimerisierung von 4.4-Dimethyl-selenolanon-(3) (5e) dargestellt werden. Die Parallelität der chemischen und spektroskopischen Eigenschaften von 6e und Selenoindigo (2, X = Se) sowie die für Indigofarbstoffe charakteristische hypsochrome Verschiebung des längstwelligen UV-Maximums bei Verlängerung des zentralen Doppelbindungssystems von 6e zeigen, daß 6e als Grundchromophor des Selenoindigos anzusehen ist.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Theoretical and Spectroscopical Investigations of Indigo Dyes, XV Basic Chromophores of Indigo Dyes and some of their Subunits from 1.4.5.8-Tetrasubstituted Octane-3.6-dionesThe 1.4.5.8-tetrasubstituted octane-3.6-diones dl-4a, meso-4b and meso-4c react with sodium sulfide to yield the basic chromophore of thionidigo 6 (X = S) as well as its subunits 8 and 9. Under comparable conditions the reactions of dl-4a with ammonia or of meso-4b and meso-4c with methylamine lead to the subunits 7 or 10, 11, and 12 of the basic chromophore of indigo 6 (X = NH) or N.N'-dimethylindigo 6 (X = NCH3). The constitution and configuration of 7-12 are assigned by means of i.r., n.m.r., u.v. and mass spectral data. 7 and 8 absorb at distinctly shorter wavelength than 6 (X = NH or S). This confirms the loss of indigo properties upon reduction of the mesomeric system 1 predicted by HMO-calculations.
    Notes: Die 1.4.5.8-tetrasubstituierten Octandione-(3.6) dl-4a, meso-4b und meso-4c liefern mit Natriumsulfid das Indigo-Grundchromophorsystem 6 (X = S) sowie die Indigo-Grundchromophor-Abbausubstanzen 8 und 9. Unter vergleichbaren Bedingungen führen die Umsetzungen von dl-4a mit Ammoniak bzw. von meso-4b und meso-4c mit Methylamin zu den Indigo-Grundchromophor-Abbausubstanzen 7 bzw. 10, 11 und 12. Konstitution und Konfiguration von 7-12 ergeben sich aus einer Analyse ihrer IR-, NMR-, UV/S- und Massenspektren. 7 und 8 absorbieren deutlich kürzerwellig als 6 (X = NH bzw. S) und bestätigen damit den auf Grund von HMO-Rechnungen vorausgesagten Verlust der Indigoeigenschaften bei Verkleinerung des mesomeren Systems 1.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 1061-1069 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyspiranes, 6. Attempted Direct Homologation of Trispiro[2.0.2.0.2.1]decan-10-one and 10-(Benzenesulfonimido)trispiro[2.0.2.0.2.1]decane with DiazocyclopropaneThe reaction of the ketone 1, m=0, with diazocyclopropane proceeds predominantly to the spiroalkylation product 9, m=0, with a minor amount of the homologation product 1, m=1. The use of the sulfonimide 23 significantly increases the yield of 1, m=1, however the production of 9, m=0, remains dominant. The product distributions are discussed in terms of possible reaction mechanisms.
    Notes: Das Keton 1, m=0, reagiert mit Diazocyclopropan überwiegend unter Spiroalkylierung zu 9, m=0. Der Anteil an Homologisierungsprodukt 1, m=1, ist gering. Bei Verwendung des Sulfonimids 23 steigt der Anteil an 1, m=1, deutlich an, jedoch bleibt auch hier die Bildung von 9, m=0, dominant. Die beobachteten Produktverteilungen werden im Hinblick auf mögliche Reaktionsmechanismen diskutiert.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 1047-1060 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polyspiranes, 5. Synthesis and Reactions of Functionalized Polyspiranes with Three-to Eight-Membered Central Ring - Polycyclopropylidenes ([n]Rotanes)The olefines 4, 5, and 6 have been proved to be valuable intermediates in the synthesis of functionalized polyspiranes and [n]rotanes. [3]Rotane (2, n = 3) and its methyl carboxylate 11 may be synthesized by way of 4, the functionalized polyspiranes 19, m = 1,2, 21, m = 0,1,2, and 1, m = 0,1,2, by way of 5. The ketones 1, m = 0,1,2, may then be transformed to the corresponding [n]rotanes 2, n = 4,5,6. The factors controlling the pronounced regioselectivity in the cycloaddition of p-nitrobenzenesulfonyl azide to 19, m = 0,1,2, are discussed, the stepwise ring enlargement of 6 to yield 28 and 29 as potential precursors of 2, n = 7,8, is described.
    Notes: Die Olefine 4, 5 und 6 haben sich als wertvolle Zwischenprodukte zur Synthese funktionalisierter Polyspirane und [n]Rotane erwiesen. [3]Rotan (2, n = 3) sowie dessen Carbonsäure-methylester 11 können über 4, die funktionalisierten Polyspirane 19, m = 1,2, 21, m = 0,1,2, und 1, m = 0,1,2, über 5 dargestellt werden. Die Ketone 1, m = 0,1,2, lassen sich anschließend in die zugehörigen [n]Rotane 2, n = 4,5,6, überführen. Der Grund für die ausgeprägte Regioselektivität der Cycloaddition von p-Nitrobenzolsulfonsäureazid an 19, m = 0,1,2, wird diskutiert, die schrittweise Ringerweiterung von 6 zu 28 und 29 als potentiellen Vorläufern von 2, n = 7,8, beschrieben.
    Type of Medium: Electronic Resource
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