Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Thiirene als Zwischenstufen der Thermolyse von 1,2,3-Thiadiazolen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1769-1778 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thiirenes as Intermediates in the Thermolysis of 1,2,3-ThiadiazolesThermolysis of the isomeric thiadiazoles 1a or 1b in moist 2,2′-oxydiethanol (3) yields the ketone 6, the thiophene 7, the alkyne 8, and the disulfide 11, the structure of which was determined by an X-ray analysis. In the presence of diphenylacetylene (15) 1a and 1b react to give the thiophenes 16a and 16b in the same ratio. This implies that the primary products of thermolysis, the 1,3-diradicals 13, can be trapped by alkynes. The formation of identical thiophenes from isomeric thiadiazoles 1 can be understood in terms of an equilibrium between the primary fragments 13 via the thiirene 14. Similarly, the ketone 6 seems not to result from 8 but from 14.
    Notes: Bei der Thermolyse der stellungsisomeren Thiadiazole 1a oder 1b in feuchtem 2,2′-Oxydiethanol (3) entstehen das Keton 6, das Thiophen 7, das Alkin 8 und das durch eine Röntgenstrukturanalyse eindeutig aufgeklärte dimere Disulfid 11. In Gegenwart von Diphenylacetylen (15) bilden sich aus 1a und 1b die Thiophene 16a und 16b im selben Verhältnis. Die bei der Thermolyse zunächst entstehenden 1,3-Diradikale 13 können demnach durch Alkine abgefangen werden. Die Bildung identischer Thiophene aus isomeren Thiadiazolen 1 läß sich durch ein Gleichgewicht der Primärfragmente 13 verstehen, das sich über das Thiiren 14 einstellt. Auch das Keton 6 scheint nicht aus 8, sondern aus 14 zu entstehen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120528
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Verdrillte Oxalsäurederivate Die Kristall- und Molekülstruktur von N,N,N′,N′-Tetramethyloxamid und -monothiooxamid (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1159-1166 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Twisted Oxalic Acid Derivatives The Crystal and Molecular Structure of N,N,N′,N′-Tetramethyloxamide and -monothiooxamideThe structures of the title compounds (2 and 3) have been determined from X-ray data, and refined to R = 0.065 (2) and 0.057 (3) respectively. 2 crystallizes in the space group C2/c, 3 in the space group P21/c. - In the crystal 2 exhibits a configuration in which the two halves of the molecule are twisted by 71.4°. This angle amounts to 87.4° in 3.
    Notes: Die Strukturen der Titelsubstanzen (2 und 3) wurden röntgenographisch bestimmt und bis zu R-Werten von 0.065 (2) bzw. 0.057 (3) verfeinert. 2 kristallisiert in der Raumgruppe C2/c, 3 in der Raumgruppe P21/c. - 2 liegt im Kristall in einer Konfiguration vor, bei der die beiden Molekülhälften um 71.4° gegeneinander verdrillt sind; bei 3 beträgt dieser Winkel 87.4°.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100339
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Reactions of N-sulfonylalkylamines with ynamines  -  formation of 2H-1,2-thiazete 1,1-dioxides, novel thioketene S,S-dioxide dimers, and other s,n-heterocycles (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 1795-1800 
    Details
    ISSN: 0947-3440
    Keywords: [2 + 2] Cycloadditions ; 2H-1,2-Thiazete 1,1-dioxides ; Amidinosulfenes, in situ formation of ; Diaminothioketene S,S-dioxide ; 1,3-Dithietane 1,1,3,3-tetraoxide ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Sulfonylalkylamines 2a, b react with ynamines 3 to give primarily 2H-1,2-thiazete 1,1-dioxides 4. But, except for the 4-triphenylsilyl species 4a, b, these products are unstable and undergo electrocyclic ring opening to very reactive amidinosulfenes 5, which are transformed into different products, depending on the ynamine substituents R2. The 1,3-dithietane 1,1,3,3-tetraoxide 8 is formed from N-sulfonylisopropylamine (2a) and the trimethylsilyl-substituted ynamine 3b via amidinosulfene 5c and probably thioketene S,S-dioxide 7. On the other hand, (isopropylamidino)sulfene 5d dimerizes to the 2H-1,5,2-dithiazine 9 and also gives the [2 + 4] cycloadducts 10a, 11a by reaction with 2a and ynamine 3c, respectively. In contrast, it was possible to trap phenyl-substituted amidinosulfenes 5e-h by addition of water or methanol.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1995199510251
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Electrophile-induced cyclizations of silyl-substituted 4-alken-1-olsDedicated to Professor Wolfgang Lüttke on the occasion of his 75th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 501-507 
    Details
    ISSN: 0947-3440
    Keywords: Tetrahydrofurans, formation of ; Cyclization, stereocontrolled ; Vinylsilanes ; Allylsilanes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Silyl-substituted 4-alken-1-ols cyclize in the presence of a wide range of electrophilic reagents to give substituted tetra-hydrofurans. The silyl group accelerates ring closure by its β-effect and its position determines the efficiency of stereo-control. Thus, a vinylic silyl group as in 1, 3-9 gives mixtures of 2,5-disubstituted tetrahydrofurans 2, 10-21, favoring formation of the trans isomer. In contrast, an allylic silyl group as in 28-30 exerts a high degree of stereocontrol, generally affording 2,3-trans-disubstituted tetrahydrofurans 31-36.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950369
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Synthesis of Functionalized Cyclopentanes, Cyclohexanes and Cycloheptanes by a Silicon-Induced Domino Reaction (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 1811-1821 
    Details
    ISSN: 0947-3440
    Keywords: Domino reaction ; Functionalized cyclopentanes, -hexanes and -heptanes ; Tetrahydrofurans ; Oxetanes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-Functionalized cyclopentanes, -hexanes and -heptanes are obtained by addition of lithiated silyldithioacetals 7 to epoxyhomoallyl tosylates 4-6, The reaction involves a cascade of epoxide ring opening, of Brook 1,4-rearrangement and tosylate substitution. The method is particularly suitable for the preparation of cyclopentanes, whereas cyclohexanes and -heptanes are formed in yields only up to 49%. Use of enantiomerically pure epoxides provides optically active cyclopentanes (S)-10b, d, 11a as well as oxetanes (S)-14a, b. Hydrolysis of the dithioacetal function leads to the corresponding ketones 12, Cyclization of epoxide 24b gives an anellated cyclopentane 26, the configuration of which was established by X-ray structural analysis of dinitrobenzoate 27. Use of epoxide 29b provides the anellated tetrahydrofuran 30.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961115
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The 2,4-Bis(diphenylmethylene)-1,3-cyclobutane-dione Diradical Dianion and its Sulphur Analogues2) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1397-1402 
    Details
    ISSN: 0009-2940
    Keywords: Cyclobutane-1,3-diones ; Cyclobutane-1,3-dithiones ; Radical anions ; Diradical dianions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,4-Bis(diphenylmethylene)-1,3-cyclobutanedione (1) is transformed into its sulphur analogues 2 and 3 with Lawesson's or Davy's reagent 5a,b. An X-ray structural analysis is performed on 3. The electrochemistry of these compounds is surveyed. The products of the electrochemical reduction exhibit ESR spectra, which could not be attributed to the radical anions 1-•, 2-•, and 3-•. Extensive semiempirical AM1/Cl calculations suggest the spectra to correspond to the diradical dianions. The experimental data are discussed in terms of the theoretical results.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240613
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Kristall- und Molekülstruktur eines Ketens, eines Thioketens und eines Thioketen-S-oxids (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2698-2708 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal and Molecular Structures of a Ketene, a Thioketene, and a Thioketene S-OxideStarting from the thioketene 8, the corresponding ketene 7 is accessible via oxidative desulfurization by 1-pyrroline 1-oxides and the thioketene S-oxide 9 by oxidation with a peracid: 9 is isolated as a mixture of diastereomers 9a,b, The structures of the heterocumulenes 7,8, and 9a have been determined from X-ray data and refined to R = 0·063 (7), 0·051 (8), and 0·068 (9a), respectively. In accordance with considerations based on hybridisation, the heterocumulene system in 7, 8, and 9a is linear, but the oxygen atom in 9a is bent off in the mirror plane of the molecule. By comparison with literature data, the bond distances in the heterocumulene moiety of 7, 8, and 9a allow insights into the electron-distribution in various classes of heterocumulenes. The comparison of 7, 8, and 9a with one another reveals striklingly low variations of the C = C distance.
    Notes: Ausgehend vom Thioketen 8 sind durch oxidative Entschwefelung mit 1-Pyrrolin-l-oxiden das Keten 7 und durch Persäure-Oxidation das Thioketen-S-oxid 9 zugänglich, das als Diastereomerengemisch 9a, b anfällt. Die Strukturen der Heterocumulene 7,8 und 9a wurden röntgenographisch bestimmt und bis zu R-Werten von 0·063 (7), 0·051 (8) bzw. 0·068 (9a) verfeinert. Im Einklang mit Hybridisierungsvorstellungen ist das Heterocumulensystem in 7, 8 und 9a linear, aber das Sauerstoffatom in 9a in der Spiegelebene des Moleküls abgewinkelt. Die Bindungslängen im Heterocumulenteil von 7,8 und 9a erlauben im Vergleich mit Literaturdaten Aufschlüsse über die Elektronenverteilung in verschiedenen Heterocumulen-Klassen. Der Vergleich von 7,8 und 9a untereinander zeigt auffallend geringe Änderungen im C = C-Abstand.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120738
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Cycloadditionsreaktionen von Heterocumulenen, XXIV. Selenazol-Derivate aus Carbondiselenid und 3-(Dimethylamino)-2H-azirinen (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2516-2525 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloaddition Reactions of Heterocumulenes, XXIV. Selenazole Derivatives from Carbon Diselenide and 3-(Dimethylamino)-2H-azirines3-Selenazolines 5 result from the reaction of carbon diselenide (1) with 2-phenyl-substituted azirines 2a,b via 1,2-cleavage. In the 2,2-dimethylazirine 2c 1 induces 1,3-ring-opening to give the zwitterionic selenazoline 8a which in solution exists exclusively as isoselenocyanate 8B. Reactions of 8 are possible from form A as well as from B. The 2-monosubstituted azirine 2d reacts with 1 to give the 2,2′-biselenazole 23 and the 1-selenomesoxaldiamide 24. The constitution 23 was derived from an X-ray structural analysis.
    Notes: Aus Carbondiselenid (1) und den 2-Phenyl-substituierten Azirinen 2a, b entstehen unter 1,2-Bindungsspaltung die 3-Selenazoline 5. Beim 2,2-Dimethylazirin 2c bewirkt 1 1,3-Ringöffnung zum zwitterionischen Selenazolin 8a, das in Lösung ausschließlich als Isoselenocyanat 8B vorliegt. Reaktionen von 8 sind sowohl aus der Form A wie aus B möglich. Das 2-monosubstituierte Azirin 2d gibt mit 1 das 2.2′-Biselenazol 23 und das 1-Selenomesoxalsäure-diamid 24. Die Konstitution 23 ergibt sich aus einer Röntgenstrukturanalyse.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821150714
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Kristall- und Molekülstruktur eines beständigen cyclischen Sulfenylcarboxylats ohne “bond-no bond”-Resonanz-Stabilisierung: 5,7-Di-tert-butyl-3H-2,1-benzoxathiol-3-on (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 3842-3850 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal and Molecular Structure of a Persistent Cyclic Sulfenylcarboxylate without Bond-No Bond-Resonance Stabilization: 5,7-Di-tert-butyl-3H-2,1-benzoxathiol-3-oneThe title compound 10a was synthesized in a hitherto unknown ring contraction reaction. The structure of 10a has been determined from X-ray data and refined to R = 0.04. 10a crystallizes in the rhombic space group Pna21. In the heterocyclic part the molecule is nearly planar. Comparison of 10a with sulfenylcarboxylate 3a and sulfenylcarboxylate 12b indicates the effect of bond-no bond-resonance on molecular parameters.
    Notes: Die Titelverbindung 10a konnte in einer bisher nicht beschriebenen Ringverengungsreaktion dargestellt werden. Die Struktur von 10a wurde röntgenographisch bestimmt und bis zu R = 0.04 verfeinert. 10a kristallisiert in der rhombischen Raumgruppe Pna21. Das Molekül ist im heterocyclischen Teil fast planar. Der Vergleich von 10a mit dem Sulfenylcarboxylat 3a und dem Sulfinylcarboxylat 12b gibt Hinweise auf die Auswirkung von bond-no bond-Resonanz auf die Molekülparameter.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821151215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Thioketen-Synthesen, VII. Thioketene durch [3 + 2]-Cycloreversion von 1,3-Dithiolan-Derivaten (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1165-1175 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thioketene Syntheses, VIII.  -  Thioketenes by [3+2] Cycloreversion of 1,3-Dithiolane Derivatives2-Alkylidene-1,3-dithiolanes are transformed into S,S-dioxides 1 and S-ethyl- 2 or S-arylsulfonium salts 3. After deprotonation at C-5 they form in a [3 + 2] cycloreversion thioketenes 5, which can be trapped as thioamides 17, 18. The stabilized thioketenes 5e, i-k afford 1:1 cycloadducts 24a, b, 27a-d with azomethines; in addition, thioketene 5j provides a dimer 28j, which was characterized by an X-ray structural investigation.
    Notes: 2-Alkyliden-1,3-dithiolane werden in S,S-Dioxide 1 und S-Ethyl-2 oder S-Arylsulfonium-Salze 3 übergeführt. Nach Deprotonierung an C-5 bilden sich in einer [3 + 2]-Cycloreversion Thioketene 5, die als Thioamide 17, 18 abgefangen werden können. Die stabilisierten Thioketene 5e,i-k liefern mit Azomethinen 1: 1-Cycloaddukte 24a,b, 27a-d; das Thioketen 5j reagiert daneben zu einem Dimeren 28j, das durch Röntgenstrukturanalyse charakterisiert wurde.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881210624
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...