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  • 1
    Electronic Resource
    Electronic Resource
    Tetraalkyl-p-urazines and their cation radicals (1991)
    s.l. : American Chemical Society
    The @journal of organic chemistry 56 (1991), S. 1045-1051 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00003a027
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  • 2
    Electronic Resource
    Electronic Resource
    The Crystal Structure of trans-2,2′-AzoquinoxalineDedicated to Prof. Dr. Silvio Fallab on the occasion of his 60th birthday (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 581-583 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of the title compound obtained from 2(1H)-quinoxalinone oxime by the template effect of Co(II) and Ni(II) ion has been determined by three dimensional X-ray analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680307
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  • 3
    Electronic Resource
    Electronic Resource
    Chemische Reaktionen mit Fischer-Carben-Komplexen des 1,6-Methano[10]annulensHerrn Kollegen Günther Wilke, Mülheim (Ruhr), zum 70. Geburtstag gewidmet (1994)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 77 (1994), S. 2303-2322 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of Fischer Carbene Complexes of 1,6-Methano[10]annuleneThe new Fischer carbene complexes 7, 8, and 10 of 1,6-methano[10]annulene as well as the bis(carbene) complex 15, were readily available in moderate yields by using the classical Fischer method (Schemes 1 and 2). The complexes 5 and 7 reacted easily with several alkynes under benzo-annulation conditions (Dötz reaction). Depending on the workup conditions, the new benzoquinones 16 and 17 (Scheme 5), hydroquinones 19 and 20 (Scheme 6), and protected hydroquinones 23-25 (Schemes 6 and 7) were synthesized. Surprisingly, in one run we were able to isolate the air-stable [Cr(η6-arene)(CO)3] complex 26 (Scheme 7). The X-ray structure and NMR data of 26 established a remarkable perturbation of the 10π perimeter of the 1,6-methano[10]annulene part in the hydroquinones 19-26, but no evidence of a σ-homoaromatic “bis(trinorcaradiene)” system. The first double Dötz reaction of 15 with hex-3-yne resulted in the formation of the “anti”-dibenzo-annulated 1,6-methano[10]annulene 32 (Scheme 8), which does not exist furthermore as a π-homoaromatic system, but as its σ-homoaromatic valence isomer.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19940770818
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  • 4
    Electronic Resource
    Electronic Resource
    Elektron-Donor-Acceptor-Verbindungen, XXXI. Elektron-Donor-Acceptor-[3.3]Paracyclophane mit N,N,N′,N′-Tetramethyl-p-phenylendiamin (TMPD) als Donor-Einheit (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2827-2834 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electron Donor-Acceptor Compounds, XXXI. Electron Donor-Acceptor [3.3]Paracyclophanes with N,N,N′,N′-Tetramethyl-p-phenylenediamine (TMPD) as Donor UnitThe electron donor-acceptor [3.3]paracyclophanes 1 and 2 which contain the combination of N,N,N′,N′-tetramethyl-p-phenylenediamine and p-benzoquinone were synthesized starting from 3 and 4 via 5, 7, 9, 11, 13 and 6, 8, 10, 12, 14, respectively. Charge transfer(CT) absorptions of the pair of isomers 1 and 2 differ considerably as a consequence of the orientation dependence of CT transitions. Based on an X-ray structure analysis, special features of the molecular and crystal structure of 2 are discussed.
    Notes: Die Elektron-Donor-Acceptor-[3.3]Paracyclophane 1 und 2, die die Kombination N,N,N′,N′-Tetramethyl-p-phenylendiamin und p-Benzochinon enthalten, wurden ausgehend von 3 und 4 über 5, 7, 9, 11 und 13 bzw. 6, 8, 10, 12 und 14 synthetisiert. Die Charge-Transfer(CT)-Absorptionen des Isomerenpaars 1 und 2 zeigen als Folge der Orientierungsabhängigkeit des CT-Übergangs beträchtliche Unterschiede. Die Molekülstruktur und Gitterpackung von 2 werden anhand einer Röntgenstrukturanalyse diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160809
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  • 5
    Electronic Resource
    Electronic Resource
    2,4-Dialkylsubstituierte Carbono- und Thiocarbonohydrazide, Reaktionen mit Carbonylverbindungen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3461-3481 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2,4-Dialkyl Substituted Carbono- and Thiocarbonohydrazides, Reactions with Carbonyl Compounds2,4-Dialkyl substituted carbono- and thiocarbonohydrazides (4) were prepared from alkylhydrazines and phosgene or thiophosgene. Mono carbonyl compounds reacted with 4 (molar ratio 1 : 1) to yield hexahydro-1,2,4,5-tetrazines (9, 14; exception 13). Aldehydes in excess generally afforded dihydrazones (3); formaldehyde, however, yielded 1,1′-methylenebis(hexahydro-1,2,4,5-tetrazines) (10) as well as the bicyclic compounds 11 and 12. The constitution of 11 was confirmed by X-ray analysis of 11b. Dialdehydes and aliphatic or alicyclic α-diketones reacted with 4 to give double hexahydro-1,2,4,5-tetrazine derivatives (19), aryl substituted α-diketones on the other hand yielded cyclic dihydrazones (15) and/or mono-hexahydro-1,2,4,5-tetrazines (16).
    Notes: 2,4-Dialkylsubstituierte Carbono- und Thiocarbonohydrazide (4) wurden aus Alkylhydrazinen und Phosgen bzw. Thiophosgen hergestellt. Monocarbonylverbindungen reagierten mit 4 (Molverhältnis 1:1) zu Hexahydro-1,2,4,5-tetrazinen (9, 14; Ausnahme 13); im Überschuß ergaben Aldehyde gewöhnlich Dihydrazone (3), Formaldehyd jedoch lieferte 1,1′-Methylenbis(hexahydro-1,2,4,5-tetrazine) (10) sowie die bicyclischen Verbindungen 11 und 12. Die Konstitution von 11 wurde durch Röntgenstrukturanalyse von 11b gesichert. Dialdehyde und aliphatische bzw. alicyclische α-Diketone reagierten mit 4 zu doppelten Hexahydro-1,2,4,5-tetrazin-Derivaten (19), arylsubstituierte α-Diketone dagegen lieferten cyclische Dihydrazone (15) und/oder Monohexahydro-1,2,4,5-tetrazine (16).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831161019
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  • 6
    Electronic Resource
    Electronic Resource
    Cycloarenes, a New Class of Aromatic Compounds, II. Molecular Structure and Spectroscopic Properties of Kekulene (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3504-3512 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloarene, eine neue Klasse aromatischer Verbindungen, II. Molekülstruktur und spepktroskopische eigenschaften von KekulenDie Molekülstruktur von Kekulen (1) wurde durch Röntgen-Strukturanalyse bestimmt. Aus den Bindungslängen von 1 wird auf eine bemerkenswerte Lokalisation von aromatischen Sextetts und Doppelbindungen im Sinne der Formulierung 1b geschlossen. - Das Problem der annulenoiden oder benzoiden Diatropie von 1 wird an Hand der 1H-NMR-Spektren diskutiert. Die experimentellen Ergebnisse stützen in Übereinstimmung mit neueren theoretischen Berechnungen die Annahme einer vorherrschenden Ringstrom-Induktion in den benzoiden-Untereinheiten von 1 und schließen einen wesentlichen Beitrag annulenoider Strukturen wie 1a aus. - Absorptions-und Emissionsspektren von 1 sowie Nullfeld-Aufspaltungsparameter des angeregten Triplettzustands von 1 werden diskutiert.
    Notes: The molecular structure of kekulene (1) was determined by X-ray structure analysis. From the bond lengths of 1 a remarkable localisation of aromatic sextets and double bonds is concluded (cf. formula 1b). - The problem of annulenoid versus benzenoid diatropicity in 1 is discussed on the basis of 1H NMR absorptions. These data, in agreement with recent theoretical calculations, support a predominant ring-current induction in the benzenoid subunits of 1 and rule out a significant contribution of annulenoid structures like 1a. - Absorption and emission spectra of 1 are discussed as are the zero-field splitting parameters of the excited triplet state of 1.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831161022
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  • 7
    Electronic Resource
    Electronic Resource
    Elektron-Donor-Acceptor-Verbindungen, XXXIV. Höhere [n.n]Paracyclophan-Chinhydrone: Synthese, Molekülstruktur und spektroskopische Eigenschaften (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3831-3845 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electron Donor-Acceptor Compounds, XXXIV. Higher [n.n]Paracyclophane Quinhydrones: Synthesis, Molecular Structure, and Spectroscopic PropertiesCharge-transfer(CT) absorptions in dependence on conformation-related donor-acceptor arrangements were investigated for [n.n]paracyclophane quinhydrones with n = 4, 5, and 6. Based on results of the X-ray structure analysis special aspects of the molecular and crystal structure of [4.4]paracyclophane quinhydrone 2 are discussed. - The two stereoisomeric tetramethoxy[5.5]-paracyclophanes 3 and 4 were prepared starting from 5 via 6-11 as well as by the alternative route via 12 and 13. The structural assignment of 3 and 4 was determined by X-ray structure analysis of 4. A thermal isomerisation 3 ⇌ 4 does not occur even at higher temperatures. On the other hand, partial oxidative demethylation of 3 and 4 led to a rapidly equilibrating mixture of the [5.5]paracyclophane quinhydrones 15 and 16. - In the [6.6]paracyclophane series the barrier to the mutual interconversion of pseudoortho and pseudogeminal isomers is further reduced. Therefore, the analogous synthetic route from 17 via 18-22 yielded only one tetramethoxy[6.6]paracyclophane 23 and only one [6.6]paracyclophane quinhydrone 24.
    Notes: Charge-Transfer(CT)-Absorptionen in Abhängigkeit von der konformations-bedingten Donor-Acceptor-Anordnung wurden für [n.n]Paracyclophan-Chinhydrone mit n = 4, 5 und 6 untersucht. Anhand der Röntgen-Strukturanalyse werden besondere Aspekte der Molekül- und Kristallstruktur des pseudogeminalen [4.4]Paracyclophan-Chinhydrons 2 diskutiert. - Die beiden stereoisomeren Tetramethoxy[5.5]paracyclophane 3 und 4 wurden ausgehend von 5 über 6-11 sowie über 12 und 13 dargestellt. Die Strukturzuordnung von 3 und 4 wurde durch Röntgen-Strukturanalyse von 4 geklärt. Eine thermische Isomerisierung 3 ⇌ 4 findet auch bei höherer Temperatur nicht statt. Dagegen führte partielle oxidative Demethylierung von 3 und 4 zu einem schnell sich einstellenden Gleichgewicht der [5.5]Paracyclophan-Chinhydrone 15 und 16. - In der [6.6]Paracyclophan-Reihe ist die gegenseitige Umwandlung von pseudoortho- und pseudogeminalen Isomeren weiter erleichtert. Der analoge Syntheseweg von 17 über 18-22 führte daher zu nur einem Tetramethoxy[6.6]paracyclophan 23 und nur einem [6.6]Paracyclophan-Chinhydron 24.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831161207
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  • 8
    Electronic Resource
    Electronic Resource
    9,12,22,25-Tetramethoxy[7.7]paracyclophan-4,17-dion:Synthese und Molekülstruktur (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 89-91 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Starting from 1,4-bis-(3-iodopropyl)-2,5-dimethoxybenzene (3) via the reaction to the corresponding bis(1,3-dithian-2-yl) compound 4 and its double alkylation by 3 the 22-membered ring system of 5 was obtained from which 9,12,22,25-tetramethoxy[7.7]paracyclophane-4,17-dione (1) was prepared. The molecular structure of 1 is discussed on the basis of an X-ray analysis.
    Notes: Ausgehend von 1,4-Bis(3-iodpropyl)-2,5-dimethoxybenzol (3) wurde über die Reaktion zu der entsprechenden Bis(1,3-dithian-2-yl)-Verbindung 4 und deren erneute doppelte alkylierung durch 3 das 22-gliedrige Ringsystem von 5 aufgebaut, aus dem 9,12,22,25-Tetramethoxy[7.7]paracyclophan-4,17-dion (1) erhalten wurde. Die Molekülstruktur von 1 wird auf der Grundlage einer Röntgen-Strukturanalyse diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200116
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  • 9
    Electronic Resource
    Electronic Resource
    [2.2](2,6)- and [2.2](2,5)Pyrazinophanes: Synthesis and Molecular Structure (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 523-533 
    Details
    ISSN: 0009-2940
    Keywords: Hofman 1,6-elimination / Pyrazine derivatives / [2.2]Pyrazinophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 1-3 and their methyl derivatives 4-7 were synthesized 2,11-dithia[3.3]pyrazinophanes 24-26 or by Hofmann 1,6-elimination of the appropriate [(5-methyl-2-pyrazinyl)methyl]trimethylammonium hydroxides followed by dimerization of the generated 2,5-dihydro-2,5-dimethylenepyrazines. α-Chlorination of the methylpyrazines 8-10 with N-chlorosuccinimide gave the required precursors 11, 12, 14, 17 and 18. The results of the X-ray structure determinations for 1-4 and 7 which indicate an unequivocal isomer assignment are discussed with regard to steric strain in these molecules. The electronic spectra of the pyrazinophanes 7-7 are reported and compared with those of the parent methylpyrazines.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230319
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  • 10
    Electronic Resource
    Electronic Resource
    1,8-Bis(diphenylamino)- and 1,8-Bis(methylphenylamino)naphthalene: Molecular Structure and Dynamic Behavior (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 723-728 
    Details
    ISSN: 0009-2940
    Keywords: 1,8-Diaminonaphthalenes, X-ray structure analysis of, conformational barriers of, dynamic behavior of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 2 and 3 have been synthesized from 1,8-diaminonaphthalene. The molecular structure of 2 has been determined by X-ray structure analysis and is discussed with regard to the arrangement of the peri-diphenylamino substituents in the crystalline state and the steric strain in the molecule. NMR studies of 3 reveal two conformational processes. Their nature is discussed and barriers are reported.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250327
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