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  • Cell & Developmental Biology  (2,281)
  • Inorganic Chemistry  (1,512)
  • Humans  (889)
  • 1990-1994  (2,671)
  • 1985-1989  (2,011)
  • 1945-1949
  • 1993  (2,671)
  • 1985  (2,011)
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  • 1990-1994  (2,671)
  • 1985-1989  (2,011)
  • 1945-1949
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  • 1
    Electronic Resource
    Electronic Resource
    Agaricus Bisporus: An assessment of its carcinogenic potency (1993)
    Springer
    Mycopathologia 124 (1993), S. 73-77 
    Details
    ISSN: 1573-0832
    Keywords: Assessment ; Cancer ; Humans ; Hydrazines ; Mushroom
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This assessment focuses on the concentrations of some chemicals present in theAgaricus bisporus mushroom, the cancer-inducing doses of these chemicals or mushroom used in the animal experiments, the total amounts of these chemicals or mushroom needed to induce cancer in these mice, and the estimated total amounts of these chemicals or mushroom needed to induce cancer in humans. By adding the estimated amounts of chemicals needed to induce cancer and by comparing it with the amount of raw mushroom needed to induce the same effect, it becomes obvious that we have accounted for less than 2% of the carcinogenic components of theAgaricus bisporus mushroom. Since some unavailable data handicapped this assessment, it should be regarded as tentative and subject to further adjustment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01103105
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  • 2
    Electronic Resource
    Electronic Resource
    Implementation of periodic acid-thiosemicarbazide-silver proteinate staining for ultrastructural assessment of muscle glycogen utilization during exercise (1985)
    Springer
    Cell & tissue research 242 (1985), S. 229-232 
    Details
    ISSN: 1432-0878
    Keywords: Skeletal muscles ; Ultrastructure ; Exercise ; Glycogen ; Humans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Distribution of glycogen particles in semithin and ultrathin sections of biopsy samples from human muscles subjected to either short- or long-term running were investigated using PAS and Periodic Acid-ThioSemiCarbazide-Silver Proteinate (PA-TSC-SP) staining methods. Glycogen particles were predominantly found immediately under the sarcolemma or aligned along the myofibrillar Iband. After long-term exhaustive exercise type-1 fibers with a few or no glycogen particles in the core of the fibers were frequently observed. The subsarcolemmal glycogen stores of these “depleted” type-1 fibers were about three times as large as after exhaustive short-time exercise. Another indication of utilization of subsarcolemmal glycogen stores during anaerobic exercise was that many particles displayed a pale, rudimentary shape. This observation suggests fragmental metabolization of glycogen. Thus, depending on type of exercise and type of fiber differential and sequential glycogen utilization patterns can be observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225582
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  • 3
    Electronic Resource
    Electronic Resource
    Einfluß der Substituenten auf Aktivierungsenthalpie-,-entropie und -volumen beim Zerfall organischer Perester (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 240-245 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Influence of Substituents on the Enthalpy, Entropy and Volume of Activation in the Decomposition of Organic PerestersThe influence of the ester group on the decomposition of organic peroxides was studied on peresters of the pivalic and neodecanoic acid with tert-butyl, tert-amyl, 1-methyl-1-propylpentyl and 1,1,4-trimethylpentyl groups at temperatures of 393 to 473 K and pressures up to 3000 bar using a flow method. As expected the half-live times decrease with increasing temperature and increase with rising pressure. With increasing bulkiness of the substituents the rates of decomposition as well as the enthalpies of activation increase. This surprising fact can be explained by the simultaneous increase of the entropies and the volumes of activation.
    Notes: Der Einfluß der Estergruppe auf den Zerfall organischer Peroxide wurde an Perestern der Pivalin- und der Neodecansäure mit tert-Butyl-, tert-Amyl-, 1-Methyl-propylpentyl- sowie 1,1,4-Trimethylpentylresten bei Temperaturen von 393 bis 473 K und Drücken bis 3000 bar in einer Strömungsapparatur untersucht. Die Zerfallshalbwertszeiten nehmen erwartungsgemäß mit steigender Temperatur stark ab und mit steigendem Druck zu. Mit zunehmender Größe der Substituenten steigen sowohl die Zerfallsgeschwindigkeiten als auch die Aktivierungsenthalpien. Dieser überraschende Effekt kann durch die Vergrößerung der Aktivierungsentropie und des Aktivierungsvolumens erklärt werden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180123
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Lewis-Acidität von Nickel(0), III. Alkalimetall-hydridotrialkylaluminat-Komplexe von Ni(CDT) (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 313-322 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Lewis Acidity of Nickel(0), III. Alkali Metal Hydridotrialkylaluminate Complexes of Ni(CDT)Ni(CDT) reacts with hydridotrialkylaluminates of the alkali metals in ether/THF or ether/amine mixtures at temperatures below -50°C to form the temperature-sensitive compounds [MA(n-Donor)n]+[R3Al—H—Ni(CDT)]- (1-7) (MA = Li, Na; R = Me, Et, iBu). An Al—H—Ni three-centre bond is present in these complexes. On the basis of NMR data, the strength of the hydridoaluminate-nickel bond and the charge on nickel, caused by the hydridoaluminate residue, are compared with the corresponding characteristics of other ligand-Ni(CDT) complexes in which donor-acceptor σ-bonds are present.
    Notes: Ni(CDT)Abkürzungen: CDT = trans, trans, trans-1,5,9-Cyclododecatrien, COD = 1,5-Cyclooctadien, MA+ (solvatisiertes) Alkalimetall-Ion, PMDTA = N,N,N′,N″N″-Pentamethyldiethylentriamin, TMEDA = N,N,N′,N′-Tetramethylethylendiamin. reagiert mit Alkalimetall-hydridotrialkylaluminaten in Ether/THF-oder Ether/Amin-Mischungen als Lösungsmittel unterhalb von -50°C zu den thermisch labilen Verbindungen [MA(n-Donor)n]+[R3Al—H—Ni(CDT)]- (1-7) (MA = Li, Na; R = Me, Et, iBu). In diesen Komplexen liegt eine Al—H—Ni-Mehrzentrenbindung vor. Anhand NMR-spektroskopischer Daten lassen sich die Stärke der Hydridoaluminat-Nickel-Bindung und die Beladung des Nickels durch den Hydridoaluminat-Rest mit den Bindungsverhältnissen in anderen Ligand-Ni(CDT)-Komplexen mit Donor-Akzeptor-σ-Bindungen vergleichen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180128
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  • 5
    Electronic Resource
    Electronic Resource
    Zur Lewis-Acidität von Nickel(0), I. Methyllithium-Komplexe von Nickel(0) (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 275-297 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Lewis Acidity of Nickel(0), I. Methyllithium Complexes of Nickel(0)The synthesis and properties of the methyllithium complexes of nickel(0) of the type (n-Donor)m-(LiCH3)Ni0(π-Ligand)n (1a-c, 16a-c, 20a-c) [n-Donor = chelating amine or THF; π-Ligand = CDT, ethene, or CO] are described. The structure of (PMDTA)(LiCH3)Ni(C2H4)2 (1b) has been determined by X-ray crystallography.  -  In these ate complexes, a carbanionic methyl group is σ-bonded to a nickel atom, the acceptor strength of which depend on the π-ligands. The chemical and spectroscopic properties indicate that the Ni—CH3 bond in the carbonyl complex is largely covalent whereas in the CDT and ethene compounds it is more polar. The CDT complex is thermolabile in solution. The findings are in agreement with the following series of increasing acceptor strength: Ni(CDT) 〈 Ni(C2H4)2 〈 Ni(CO)3.
    Notes: Es wird über die Synthese und Eigenschaften der Methyllithium-Komplexe von Nickel(0) (n-Donor)m(LiCH3)Ni0(π-Ligand)n Wir bezeichnen mitπ-Liganden solche Liganden, die als π-Akzeptoren mit einem Übergangsmetallatom dπ—pπ—oder dπ—dπ-Rückbindungen auszubilden vermögen (Alkene, CO, auch Phosphane);n-Donoren solche Liganden, die als „harte Basen“ (Ether, Amine) über ihre freien Elektronenpaare vornehmlich Hauptgruppenmetall-Ionen, d.h. „harte Säuren“ komplexieren;σ-Donoren solche Liganden, die  -  ohne über Akzeptororbitale zu verfügen  -  entweder polare Bindungen enthalten und Mehrzentrenbindungen eingehen können (Metallalkyle und -hydride) oder ein freies Elektronenpaar bereitstellen (Carbanionen, Phosphorane, Hydrid-Ion), wobei σ-Bindungen zu einem niederwertigen Übergangsmetallatom ausgebildet werden. (1a-c, 16a-c, 20a-c) mit Chelataminen oder THF als n-Donoren und CDTAbkürzungen: CDT = trans,trans,trans-l,5,9-Cyclooctadien; COT = Cyclooctatetraen; PMDTA = Pentamethyldiethylentriamin; TMEDA = Tetramethylethylendiamin; MA+A = Alkalimetall- bzw. quartäres Ammonium-Kation., Ethen oder CO als π-Liganden berichtet. Die Struktur von (PMDTA)(LiCH3)Ni(C2H4)2 (1b) wurde röntgenographisch bestimmt.  -  In diesen at-Komplexen ist eine carbanionische Methylgruppe über eine σ-Bindung an ein Nickelatom gebunden, dessen Akzeptorstärke von den π-Liganden abhängt. Chemische und spektroskopische Eigenschaften der Komplexe lassen für CDT oder Ethen als π-Liganden auf vergleichsweise polare, für den CDT-Komplex in Lösung dazu thermolabile Ni—CH3-Bindungen schließen, während für den Carbonyl-Komplex aufgrund von 13C-NMR-Daten eine überwiegend kovalente Ni—CH3-Bindung anzunehmen ist. Die Befunde stehen mit folgender Reihe zunehmender Akzeptorstärke im Einklang: Ni(CDT) 〈 Ni(C2H4)2 〈 Ni(CO)3.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180126
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  • 6
    Electronic Resource
    Electronic Resource
    Über das korrespondierende Verhalten von heteroatom-stabilisierten Carbokationen und dem Cycloheptatrien-Norcaradien-Gleichgewicht (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 620-633 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Correspondence of Heteroatom-stabilized Carbocations and the Cycloheptatriene-Norcaradiene EquilibriumThe effects of alkoxyiminium substituents on the cycloheptatriene-norcaradiene equilibria 1 ⇄ 2 have been investigated. Due to the energetics two classes of compounds were found (ΔH° 〈 0, and ΔH° 〉 0). The transfer of the substituent effect from carbocation to carbocyclus is inhibited by a p-phenylene group. From 1H and 13C NMR spectra at variable temperatures thermodynamic parameters are deduced and correlated with σR-constants obtained from 19F NMR spectroscopy. By extrapolation, the enthalpy difference for the unsubstituted cycloheptatriene and norcaradiene is calculated as 9.3 kcal/mol.
    Notes: Der Einfluß von Alkoxyiminium-Substituenten an C-7 auf die Lage des Cycloheptatrien-Norcaradien-Gleichgewichts 1 ⇄ 2 wird untersucht. Auf Grund der Energetik gibt es Verbindungen, bei denen Temperaturabsenkung eine Verschiebung des Gleichgewichts zum Norcaradien (ΔH° 〈 0) ergibt, bei anderen Beispielen ist ΔH° 〈 0. Eine p-Phenylenbrücke zwischen Kation und Carbocyclus blockiert den Substituenteneffekt. Aus den 1H- und 13C-NMR-Spektren bei verschiedenen Temperaturen wurden thermodynamische Daten ermittelt und mit den durch 19F-NMR bestimmten σR-Konstanten korreliert. Durch Extrapolation konnte die Enthalpiedifferenz des unsubstituierten Cycloheptatriens und Norcaradiens zu 9.3 kcal/mol abgeschätzt werden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180221
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  • 7
    Electronic Resource
    Electronic Resource
    Hydrated oxocarbons, IV. Silylation of 1,1-dihydroxy compounds (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 661-669 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydratisierte Oxokohlenwasserstoffe, IV. Silylierung von 1,1-Dihydroxy-VerbindungenDie Anwendung von verschiedenen Silylierungsreagenzien auf mono- und polyvicinale 1,1-Di-hydroxy-Verbindungen wurde untersucht. Mit einigen dieser Reagenzien konnten aus Ninhydrin (2) und Rhodizonsäure (17) die entsprechenden geminalen Bis(trimethylsilyloxy)-Derivate 1 und 20 gewonnen werden. Während 1 leicht zu Hexamethyldisiloxan und Indantrion (4) fragmentiert, ist 20 thermisch relativ stabil, es gibt pyrolytisch bei 500°C nur Spuren des Tetraketons 21 ab. Andere Silylierungsreagenzien bewirken unerwartete C-Alkylierung oder C-Amidierung am Dihydroxykohlenstoff. Silylierungen von Perhydroxycyclobutan und -cyclohexan führen zu Ringaufspaltungs- bzw. Verengungsprodukten.
    Notes: The action of various silylating agents on mono- and polyvicinal 1,1-dihydroxy compounds has been investigated. Some of these reagents converted ninhydrin (2) and rhodizonic acid (17) into the corresponding geminal bis(trimethylsilyloxy) derivatives 1 and 20, respectively. Compound 1 readily fragments to form hexamethyldisiloxane and indantrione (4). The rhodizonic acid derivative 20 is, however, rather stable and even on pyrolysis at 500°C gives only traces of the tetraketone 21. With other silylating agents unexpected C-alkylation or C-amidation at the dihydroxy carbon is observed. Silylation of perhydroxycyclobutane and -cyclohexane leads to ring opened and contracted products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180225
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  • 8
    Electronic Resource
    Electronic Resource
    Cycloadditionen des Triphenylallenyl-Kations mit Cyclopentadien  -  Studium des Reaktionsmechanismus unter stabilen Ionen-Bedingungen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 694-703 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions of the Triphenylallenyl Cation with Cyclopentadiene  -  Investigation of the Reaction Mechanism under Stable Ion ConditionsThe triphenylallenyl cation (5) reacts with cyclopentadiene in a concerted [4 + 2] and a stepwise [2 + 2] cycloaddition. The reaction mechanisms are elucidated by NMR spectroscopic observation of the intermediate carbenium ions.
    Notes: Das Triphenylallenyl-Kation (5) geht mit Cyclopentadien eine konzertierte [4 + 2]- sowie eine stufenweise [2 + 2]-Cycloaddition ein. Die Reaktionsmechanismen werden durch NMR-spektro-skopische Beobachtung der intermediären Carbenium-Ionen aufgeklärt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180229
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  • 9
    Electronic Resource
    Electronic Resource
    Synthese und Struktur Platin-haltiger Tripeldecker- und Tetradecker-Komplexe (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 729-740 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of Platinum-Containing Triple-Decker and Tetra-Decker ComplexesStacking of the acceptor sandwich bis(η5-2,3-dihydro-1H-1,3-diborolyl)platinum 1 (≙ (C2B2C)2Pt) with (C5H5)M fragments leads to the unsymmetrical triple-decker complexes (η5-C5H5)M-μ-(η5-C2B2C)Pt(η5-C2B2C) 2 (M = Co) and 3 (M = Ni) as well as to the symmetrical tetra-decker complexes [(η5-C5H5)M-μ-(η5-C2B2C)]2Pt 4 (M = Fe) and 5 (M = Ni). In these reactions 1 and (C5H5)Fe(C8H12) yield the tetra-decker 4, whereas with (C5H5)Co(C2H4)2 only the triple-decker 2 is formed. With [(C5H5)Ni(CO)]2 both the triple-decker 3 and the tetra-decker 5 are obtained. NMR studies on the diamagnetic complexes 2 (30 valence electrons), 4 (42 VE), and 5 (46 VE) indicate high-symmetrical conformations, or free rotation of the ligands. 2 and 3 crystallize isotypic; the X-ray structure analyses exhibit the triple-decker arrangement with antiperiplanar conformation of the heterocycles. 3 in comparison with 2 is elongated along the molecular axis. The tetra-deckers 4 and 5 also crystallize isotypic; for the first time a synclinale conformation of the bridging ligands is found.
    Notes: Aufstockung des Akzeptor-Sandwichs Bis(η5-2,3-dihydro-1H-1,3-diborolyl)platin 1 (≙ (C2B2C)2Pt) mit (C5H5)M-Fragmenten führt zu den unsymmetrischen Tripeldecker-Komplexen (η5-C5H5)M-μ(η5-C2B2C)Pt(η5-C2B2C) 2 (M = Co) und 3 (M = Ni) sowie zu den symmetrischen Tetradecker-Komplexen [(η5-C5H5)M-μ-(η5-C2B2C)]2Pt 4 (M = Fe) und 5 (M = Ni). Dabei ergibt die Reaktion von 1 mit (C5H5Fe(C8H12) den Tetradecker 4, während mit (C5H5)Co(C2H4)2 nur der Tripeldecker 2 entsteht. Mit [(C5H5)Ni(CO)]2 werden der Tripeldecker 3 und der Tetradecker 5 gebildet. NMR-Untersuchungen an den diamagnetischen Komplexen 2 (30 Valenzelektronen), 4 (42 VE) und 5 (46 VE) sprechen für hochsymmetrische Konformationen oder freie Rotation der Liganden. 2 und 3 kristallisieren isotyp; die Röntgenstrukturanalysen zeigen die Tripeldeckeranordnung mit antiperiplanarer Konformation der Heterocyclen. 3 ist im Vergleich zu 2 entlang der Molekülachse aufgeweitet. Die Tetradecker 4 und 5 kristallisieren ebenfalls isotyp, es wird erstmals eine synclinale Konformation der Brückenliganden gefunden.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180232
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  • 10
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    Ein neuer Zugang zu Alkylthio(trifluoracetyl)furanen durch thermische [3 + 2]-Cycloadditionen neuer mesoionischer 1,3-Oxathiol-4-one an Alkine (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 785-795 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Entry to Alkylthio(trifluoroacetyl)furans by Way of Thermal [3 + 2]Cycloaddition Reactions of New Mesoionic 1,3-Oxathiol-4-ones to AlkynesAs cyclic carbonyl ylides, the novel 2-alkylthio-5-trifluoroacetyl-1,3-oxathiolylium-4-olates of type 1a-d combine with dimethyl acetylenedicarboxylate across the 2,5-position with formation of non-isolable primary adducts, which release COS to give the furandicarboxylic diesters 3a-d. Methyl propiolate reacts with 1a-c to produce mixtures of the regioisomeric furancarboxylic esters 4a-c and 5a-c, whose main components 4a-c are isolable. On the other hand, the reactions of phenylacetylene, 1-diethylaminopropyne, or (Z)-1-methoxy-1-buten-3-yne with 1a proceed with regiospecific formation of the furan derivatives 6, 7, or 8, respectively. The observed regioselectivities are qualitatively discussed on the basis of MO-perturbation theory.
    Notes: Als cyclische Carbonyl-ylide nehmen die neuen 2-Alkylthio-5-trifluoracetyl-1,3-oxathiolylium-4-olate vom Typ 1a-d in 2,5-Stellung Acetylendicarbonsäure-dimethylester unter Bildung nicht-isolierbarer Primäraddukte auf, die unter COS-Abspaltung Furandicarbonester 3a-d liefern. Mit Propiolsäure-methylester reagiert 1a-c zu Gemischen aus den regioisomeren Furancarbonestern 4a-c und 5a-c, deren Hauptkomponenten 4a-c isolierbar sind. Dagegen vereinigen sich Phenylacetylen, 1-Diethylaminopropin bzw. (Z)-1-Methoxy-1-buten-3-in mit 1a regiospezifisch zu den Furan-Derivaten 6, 7 bzw. 8. Die beobachteten Regioselektivitäten werden qualitativ auf der Basis der MO-Störungstheorie diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180237
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  • 11
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    Notizen. Thermolysis and photolysis of hexachloro-tris-σ-homotropone and related compounds (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 840-844 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermolyse und Photolyse von Hexachlor-tris-σ-homotropon und verwandten VerbindungenTroponethylenacetal (2) reagiert mit überschüssigem CCl2 zu den Mono-, Bis- und Tris-Addukten 3, 4a, b und 5. Thermolyse von 5 führt nicht zum Hexachlor-tris-σ-homobenzol (1), ebensowenig wie die Photolyse des Ketons 6a, bei der unter Öffnung einer Cyclopropan-Brückenbindung das sterisch mehr gehinderte Isomere 6b erhalten wird. Die Photolyse von 8 verläuft ebenfalls nicht unter Decarbonylierung (→ 7) sondern unter Cyclopropanring-Öffnung zu 9 bzw. 10, wobei hier die von der Carbonylgruppe am weitesten entfernten Bindungen geöffnet werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180241
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  • 12
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    Schwefelextrusion aus 5(2H)-Isothiazolonen und 5(2H)-Isothiazolthionen zu intermediären Imidoylketenen und -thioketenen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 851-862 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sulfur Extrusion from 5(2H)-Isothiazolones and 5(2H)-Isothiazolethiones to give Intermediate Imidoyl Ketenes and Imidoyl ThioketenesFrom 5(2H-isothiazolethiones (2) and propylene oxide a series of new 5(2H-isothiazolones (7) was prepared. With tributylphosphane (or cyanide ions) 2 and 7 eliminated one sulfur atom. The resulting assumed imidoyl ketenes (8) and imidoyl thioketenes (3) could not be detected spectro-scopically. But by isolation of dimeric imidoyl thioketenes (1,3-dithietanes, 1) and trapping with alcohols, amines, or benzylideneisopropylamine to give derivatives of acrylic acid (4-6) or dihydropyrimidones (9) it is shown that 3 and 8 are probably intermediates.
    Notes: Aus 5(2H)-Isothiazolthionen (2) wurde mittels Propylenoxid eine Reihe neuer 5(2H)-Isothiazolone (7) hergestellt. Beide Substanzklassen reagieren mit Tributylphosphan (oder Cyanid-Ionen) unter Abspaltung eines Schwefelatoms zu vermuteten, spektroskopisch aber nicht nachgewiesenen Imidoyl-thioketenen (3) bzw. Imidoylketenen (8). Ihr intermediäres Auftreten wurde durch die Isolierung von dimeren Imidoyl-thioketenen (1,3-Dithietanen, 1) und durch Abfangreaktionen mit Alkoholen, Aminen oder Benzylidenisopropylamin zu den Derivaten der Acrylsäure 4-6 bzw. den Dihydropyrimidonen 9 wahrscheinlich gemacht.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19851180302
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    Heterocyclische β-Enaminoester, 36. Das Cycloadditions-Ringerweiterungsprinzip beim 4,5-Dihydropyrrol: 6,7-Dihydro-1H-azepine, Pyrimido[4,5-b]azepine und 1,2,4-Triazolo[5′,1′: 2,3]pyrimido[4,5-b]azepin (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 863-872 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic β-Enamino Esters, 36. The Cycloaddition-Ring Enlargement Principle on 4,5-Dihydropyrroles: 6,7-Dihydro-1H-azepines, Pyrimido[4,5-b]azepines, and 1,2,4-Triazolo[5′,1′: 2,3]pyrimido[4,5-b]azepineThe 2-amino-1-tosyl-Δ2-pyrroline enamino esters 2a, b react with dichlorotriphenylphosphorane to give the iminophosphoranes 3a, b. With acetylenic esters (4a-c) the 6,7-dihydro-1H-azepines 6a-d are formed according to the cycloaddition-ring enlargement principle. Acids hydrolyze to afford the free azepine enamino esters 7a, c, d. With phenyl isocyanate 6a gives the carbodiimide 9, which upon treatment with 5% aq. NaOH cyclizes to give the pyrimido[4,5-b]azepine 10. Analogously, isopropylamine and hydrazine lead to the 2-N-substituted bicycles 11a, b; with triethyl orthoformiate 11a yields the novel 5:6:7-tricycle 13.
    Notes: Die 2-Amino-1-tosyl-Δ2-pyrrolin-enaminoester 2a, b reagieren mit Dichlortriphenylphosphoran zu den Iminophosphoranen 3a, b. Mit Acetylenestern (4a-c) entstehen nach dem Prinzip Cycloaddition-Ringerweiterung die 6,7-Dihydro-1H-azepine 6a-d. Säuren hydrolysieren zu den freien Azepin-enaminoestern 7a, c, d. Mit Phenylisocyanat ergibt 6a das Carbodiimid 9, das sich mit 5proz. Natronlauge zum Pyrimido[4,5-b]azepin 10 ringschließen läßt; Isopropylamin und Hydrazin führt analog zu den 2-N-substituierten Bicyclen 11a, b, 11a ergibt mit Orthoameisensäure-triethylester den neuen 5:6:7-Tricyclus 13.
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    Carbonylvanadate(-I) mit ungesättigten Liganden: 51V-NMR-und IR-spektroskopische Charakterisierung der Tieftemperaturspezies [V(CO)5L]-; L = N2, Alkin, Alken, CS2 und SO2 (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 895-904 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonylvanadates(-I) Containing Unsaturated Ligands:51V NMR and IR Characterization of Low-temperature [V(CO)5L]- Complexes; L = N2, Alkyne, Alkene, CS2, and SO2UV irradiation of [Et4N]V(CO)6 + L in THF (L = alkyne, alkene) or 2-Me-THF (L = N2) at 200 K yields the pentacarbonylvanadates [V(CO)5L]- with end-on (N2) and side-on (alkynes, alkenes) coordinated ligands, respectively. [V(CO)5SO2]- (η1S) and [V(CO)5CS2]- (η2-C,S) were obtained from the reaction between [V(CO)5THF]- and L at 200 K. The N2 complex is also formed from [V(CO)5OCMe2]- and N2. The complexes are characterized by their IR and 51V NMR spectra. Shielding of the 51V nucleus decreases in the order alkene 〉 alkyne ≍ N2 〉 SO2 〉 CS2 〉 {O}. Compared to η1-coordination, η2-coordination gives rise to a deshielding contribution of 110 to 280 ppm. The compounds decompose at temperatures above 225 K (L = N2, 2-pentyne, 3-hexyne, cyclopentene, cyclohexene), 240 - 250 K (SO2, CS2, 1-pentene), or 285 K (1-hexyne); with PPh3, [V(CO)5PPh3]- is formed.
    Notes: Die UV-Bestrahlung von [Et4N][V(CO)6] + L in THF (L = Alkin, Alken) oder 2-Me THF (L = N2) bei 200 K führt zu Pentacarbonylvanadaten [V(CO)5L]- mit end-on (N2) bzw. side-on (Alkine, Alkene) gebundenen Liganden. [V(CO)5SO2]- (η1-S und [V(CO)5CS2]- (η2C,S) wurden durch Umsetzung von [V(CO)5THF]- mit L bei 200 K erhalten. Der N2-Komplex entsteht auch aus [V(CO)5OCMe2]- und N2. Die Komplexe werden durch ihre IR- und 51V-NMR-Spektren charakterisiert. Die Abschirmung am Kern 51V nimmt in der Reihe Alken 〉 Alkin ≍ N2 〉 SO2 〉 CS2 〉 {O} ab. Die η2-Koordination liefert gegenüber der η1-Koordination einen Entschirmugsbeitrag von 110 - 280 ppm. Die Verbindungen zersetzen sich bei Temperaturen oberhalb 225 K (L = N2, 2-Pentin, 3-Hexin, Cyclopenten, Cyclohexen), 240 - 250 K (SO2, CS2, 1-Penten) bzw. 285 K (1-Hexin); mit PPh3 erfolgt Umsetzung zu [V(CO)5PPh3]-.
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    (Trifluormethyl)selen(VI)-Verbindungen, Synthese und Eigenschaften von Tetrafluor(trifluormethyl)selen-halogeniden sowie Trifluormethanselenonaten (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 943-951 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Trifluoromethyl)selenium(VI) Compounds, Synthesis and Properties of Tetrafluoro(trifluoromethyl)selenium Halides and TrifluoromethaneselenonatesFluorination of CF3SeF3 with liquid F2 or AgF2 leads to CF3SeF5, which decomposes to CF4 and SeF4. With water CF4 and SeOF2 are formed. Addition of ClF to CF3SeF3 gives CF3SeF4Cl, which splits mainly into CF3Cl and SeF4. Hydrolysis provides analogously CF3Cl and SeOF2. A neutral concentrated solution of KMnO4 oxydizes CF3SeO2H in water in good yields to CF3SeO3K, the free acid of which is obtained with 74% HClO4. The aqueous solution can be concentrated up to 90%, but above this concentration spontaneous decomposition to CF4, COF2, and SeO2 occurs. Trifluoromethaneselenonates are stable at room temperature but decompose when heated.
    Notes: Die Fluorierung von CF3SeF3 mit flüssigem Fluor bzw. AgF2 führt zu CF3SeF5 das thermisch in CF4 sowie SeF4 zerfällt und mit H2O zu CF4 und SeOF2 hydrolysiert. Durch Addition von ClF an CF3SeF3 entsteht CF3SeF4Cl, das sich hauptsächlich zu CF3Cl und SeF4 zersetzt. Die Hydrolyse liefert analog CF3Cl und SeOF2. Mit wäßr., gesättigter KMnO4 liefert CF3SeO2H in guter Ausbeute CF3SeO3K, aus dem die freie Säure mit 74proz. HClO4 erhalten wird. Sie läßt sich in wäßriger Lösung bis zu 90% anreichern und zerfällt bei weiterem Konzentrieren spontan zu CF4, COF2 und SeO2. Ihre Salze sind bei Raumtemperatur stabil und explodieren beim Erhitzen.
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    Metallkomplexe mit biologisch wichtigen Liganden, XXXIV. Allyl-Palladium(II)- und Triphenylphosphan-Gold(I)-Komplexe mit Nucleobasen und Nucleosiden (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 931-942 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Complexes with Biologically Important Ligands, XXXIV. Allyl-Palladium(II) and Triphenylphosphane Gold(I) Complexes with Nucleobases and NucleosidesThe reactions of (η3-allyl)Pd(μ-Cl)2Pd(η3-allyl) (A) and (COD)Rh(μ-Cl)2Rh(COD) with nucleobases and nucleosides give the complexes (η3-C3H5)Pd(L)Cl (1) (L = inosine, adenosine, guanosine, cytosine, cytidine, 2-thiouracil, 2-thiocytosine) and (COD)Rh(cytosine)Cl (2), respectively. With adenosine and purine also ligand bridged complexes (η3-C3H5)(Cl)Pd—L—Pd(Cl)(η3-C3H5) (3) have been obtained. Ph3PAuCl reacts with the anions L′ of purine, adenine, uridine, and inosine to give the complexes Ph3PAuL′ (5). Ph3PAu+ is added to both N atoms of the dianion of uracil with formation of 6. The coordination of the nucleobases is discussed on the basis of the 1H and 13C NMR spectra. The X-ray structure of Ph3PAu(adeninate) (5b) has been determined.
    Notes: Die Umsetzung von (η3-Allyl)Pd(μ-Cl)2Pd(η3-Allyl) (A) sowie von (COD)Rh(μ-Cl)2Rh(COD) mit Nucleobasen und Nucleosiden liefert unter Spaltung der Chlorobrücken die Komplexe (η3C3H5)-Pd(L)Cl (1) (L = Inosin, Adenosin, Guanosin, Cytosin, Cytidin, 2-Thiouracil, 2-Thiocytosin) bzw. (COD)Rh(Cytosin)Cl (2). Mit Adenosin und Purin wurden auch Ligand-verbrückte Komplexe (η3-C3H5)(Cl)Pd—L—Pd(Cl)(η3-C3H5) (3) erhalten. Ph3PAuCl setzt sich mit den Anionen L′ von Purin, Adenin, Uridin und Inosin zu Ph3PAuL′ (5) um; Ph3PAu+ addiert sich an die beiden N-Atome des Dianions von Uracil unter Bildung von 6. Die Koordination der Nucleobasen wird anhand der 1H- und 13C-NMR-Spektren diskutiert. Die Struktur von Ph3PAu (Adeninat) (5b) wurde röntgenographisch bestimmt.
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    Bicyclofulvene, XI. Zur Frage der Spirokonjugation bei Spiro[cycloheptatrien-7,7′-norbornadien] (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1000-1007 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bicyclofulvenes, XI. On the Question of Spiroconjugation in Spiro[cycloheptatriene-7,7′-norbornadiene]The title compound 4 as well as the derivatives 5 und 6 have been prepared. The first band in the UV spectrum of 4 in n-heptane is blue-shifted by ca. 20 nm with respect to those of 5 and 6. Model calculations with the CNDO/S-CI method indicate that this hypsochromic shift as well as the bathochromic shift of the corresponding band of 2 relative to that of 3, cannot be explained by spiroconjugation. The thermolysis of 4 yields benzene, heptafulvalene (15), and fulveneallene (16). The latter products are probably derived from cycloheptatrienylidene (14) as an intermediate.
    Notes: Die Titelverbindung 4 sowie die Derivate 5 und 6 wurden dargestellt. Die erste Bande im UV-Spektrum von 4 in n-Heptan zeigt eine hypsochrome Verschiebung um ca. 20 nm verglichen mit den Banden in 5 und 6. Modellrechungen mit der CNDO/S-CI-Methode zeigen, daß, sowohl diese hypsochrome Verschiebung als auch die bathochrome Verschiebung der entsprechenden Bande von 2 im Vergleich zu 3 nicht auf Spirokonjugation beruht. Die Thermolyse von 4 ergibt neben Benzol Heptafulvalen (15) und Fulvenallen (16). Diese Produkte machen eine Spaltung von 4 in Benzol und Cycloheptatrienyliden (14) wahrscheinlich.
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    Neue Reagenzien, XXXII. Alkyldiphenylbismutane: Synthese, Eigenschaften und Halogenolyse (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1031-1038 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Reagents, XXXII. Alkyldiphenylbismutanes: Synthesis, Properties, and HalogenolysisAlkyldiphenylbismutanes 1 have been synthesized for the first time (61-92%). These compounds are air sensitive, not spontaneously inflammable liquids which decompose not below ≍ 170°C. The diphenylbismutino group is a very good equivalent for Cl- or Br-substituents at aliphatic residues since halogenolysis of the Bi-Alk bond with SO2Cl2 or Br2 already occurs at -40 to 0°C (corresponding fissions of As-Alk and Sb-Alk bonds afford heating to ≍ 130 or ≍ 220°C).
    Notes: Erstmals konnten Alkyldiphenylbismutane 1 synthetisiert werden (61-92%). Es sind luftempfindliche, nicht selbstentzündliche Flüssigkeiten, die sich erst bei ≍ 170°C zersetzen. Die Diphenylbismutino-Gruppe ist ein sehr gutes Äquivalent für aliphatisch gebundenes Chlor oder Brom, da die Halogenolyse der Bi-Alk-Bindung mit SO2Cl2 oder Br2 bereits bei - 40 bis 0°C abläuft (entsprechende Spaltungen von As-Alk- und Sb-Alk-Bindungen erfolgen bei ≍ 130 bzw. ≍ 220°C).
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    Dimere Phospha- und Thiastannylene: Ylidartige Diphospha- und Dithiadistannetane (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1045-1049 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dimeric Phospha- and Thiastannylenes: Ylide-type Diphospha- and DithiadistannetanesBis(di-tert-butylphosphino)tin(II) (1) is obtained from the reaction of potassium di-tert-butyl-phosphide with stannous chloride or with the stannous chloride-triethylphosphane complex. Bis(tert-butylthio)tin(II) (2) is prepared by reaction of (η5-C5H5)2Sn with 2-methyl-2-propanethiol or from stannous chloride and (tert-butylthio)trimethylsilane. In solution, 1 and 2 are PR2-and SR-bridged dimers, respectively. NMR spectra indicate that rapid scrambling of terminal and bridging substituents occurs in 2 but not in the cyclic \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm P}\limits^ + - \mathop {\rm S}\limits^{\rm - } {\rm n} $\end{document} ylide 1.
    Notes: Bis(di-tert-butylphosphino)zinn(II) (1) entsteht durch Reaktion von Kalium-di-tert-butylphos-phid mit Zinndichlorid oder dem Zinndichlorid-Triethylphosphan-Komplex. Bis(tert-butylthio)-zinn(II) (2) wird hergestellt durch Umsetzung von (η5-C5H5)2Sn mit 2-Methyl-2-propanthiol und entsteht auch bei der Reaktion von Zinndichlorid mit (tert-Butylthio)trimethylsilan. 1 und 2 liegen in Lösung als PR2- bzw. SR-verbrückte Dimere vor. Kernresonanzspektren zeigen, daß bei dem cyclischen \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm P}\limits^ + - \mathop {\rm S}\limits^{\rm - } {\rm n} $\end{document}-Ylid 1 im Gegensatz zu 2 auch in Ethern keine raschen Platzwechselvorgänge (Brücke/terminal) ablaufen.
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    Regioselektive Addition von Grignard-Reagenzien an 3-Methoxy- und 3-Nitrophthalsäureanhydrid (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1058-1070 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regioselective Addition of Grignard Reagents to 3-Methoxy- and 3-Nitrophthalic AnhydrideThe regioselectivity in the addition of the grignard reagents 5a and 6a to the anhydrides 1 and 2 is determined by the solvent system: in a highly selective manner (3: 97), the meta carbonyl group is attacked in tetrahydrofuran/tetramethylethylenediamine, while predominant, but relatively unselective (maximum 78:22) addition to the ortho carbonyl group is observed in diethyl ether. The influence of the solvent system on the regioselectivity is discussed. The LUMO-coefficients of the carbonyl carbon atoms in 1 and 2 were calculated.
    Notes: Die Addition der Grignard-Reagenzien 5a und 6a an die Anhydride 1 und 2 wird entscheidend vom Reaktionsmedium beeinflußt: in Tetrathydrofuran/Tetramethylethylendiamin wird hochselektiv (3: 97) die meta-ständige, in Diethylether dagegen überwiegend, aber mit nur geringer Selektivität (maximal 78: 22), die ortho-Carbonylgruppe angegriffen. Die Strukturen der dabei erhaltenen Addukte werden durch Umwandlung in die Ester 7-10, in die Lactone 11 sowie in die Ketone 12 und 13 bewiesen. Im Zusammenhang mit dem Versuch, die lösungsmittelabhängige Regioselektivität zu interpretieren, wurden die LUMO-Koeffizienten der Carbonylkohlenstoff-atome in 1 und 2 berechnet.
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    Cyanphosphorverbindungen, 8. Das ungewöhnliche Anion P2C10N102- (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1078-1085 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyanophosphorus Compounds, 8. The Unusual Anion P2C10N102-The reaction P(CN)3 + CN- (as [18]crown-6-sodium salt) leads via the spectroscopically identified P(CN)4 - to a disproportionation PIII → PI + PV. P(CN)2 - and P2C10N102- (1) have been isolated as products (with Ph3PCHPPh3 + as counter ion). In the latter an anionic aminomalononitrile bridge connects a dicyanophosphino and a pentacyanophosphate group, -P(CN)2 and - P(CN)5-, respectively.
    Notes: Die Reaktion P(CN)3 + CN- (als [18]Krone-6-Natriumsalz) führt über das nur spektroskopisch erkennbare P(CN)4- zur Disproportionierung PIII → PI + PV. Als Produkte können (mit Ph3PCHPPh3 + als Kation) P(CN)2- und P2C10N102- (1) gefaßt werden. In letzterem sind ein Dicyanphosphino-und ein Pentacyanophosphatrest, -P(CN)2 bzw. - P(CN)5-, über eine anionische Aminomalononitrilbrücke miteinander verbunden.
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    Addition von Aldehyden an aktivierte Doppelbindungen, XXXV. α-Ketosäuren als Äquivalent für Aldehyde in der Thiazoliumsalz-katalysierten Addition (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1115-1125 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XXXV. α-Keto Acids as an Equivalent for Aldehydes in the Thiazolium Salt-Catalyzed Additionα-Keto acids can be used instead of aldehydes in the thiazolium salt-catalyzed addition to vinyl ketones. The yields of γ-diketones 1-7 resulting from the aliphatic α-keto acids are equivalent with those obtained from the aldehydes. The diketo acids 9-19 are prepared from the easily accessible 2-oxodiacids. Phenylpyruvic acids are easier to prepare than the phenylacetalehydes and give better yields compared with the corresponding aldehydes in the addition to vinyl ketones leading to the γ-diketones 20-29. These diketones are converted to cyclopentenones. The dihydrofurylglyoxylic ester 40 leads to the diketone 43, which is converted to the diketone 44. There is no aldehyde known equivalent to that keto acid.
    Notes: α-Ketosäuren können anstelle von Aldehyden in die Thiazoliumsalz-katalysierte Addition an Vinylketone eingesetzt werden. So entstehen die γ-Diketone 1-7 aus den α-Ketosäuren der aliphatischen Reihe in Ausbeuten, die der Aldehydaddition entsprechen. Aus den gut zugänglichen 2-Oxodisäuren werden die Diketosäuren 9-19 erhalten. Phenylbrenztraubensäuren sind besser als Phenylacetaldehyde zu synthetisieren und liefern in der Addition an Vinylketone zu den γ-Diketonen 20-29 bessere Ausbeuten. Diese Diketone wurden in Cyclopentenone übergeführt. Aus dem Dihydrofurylglyoxylsäure-ethylester 40 kann das Diketon 43 und daraus das Diketon 44, erhalten werden, ein entsprechender Aldehyd ist nicht bekannt.
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    Masthead (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985) 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/cber.19851180501
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    Heterocyclische 8π-Systeme, 16. Eliminierung an 2-Alkoxy-3-hydroxyindolinen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1726-1731 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heterocyclic 8π-Systems, 16. Elimination Reactions of 2-Alkoxy-3-hydroxyindolinesThermolysis of 2-ethoxy-3-hydroxyindolines 1a-f affords oxindoles 3a-f as main products and the corresponding 3-indolinones 2a-f as by-products. The reaction course via indole 2,3-oxide intermediates is discussed. For this reason rearrangement reactions of 3-hydroxyindoleninium salts 4a, f are investigated.
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    Chirale Lactole, IV. Selektivitäten bei Acetalisierungsreaktionen enantiomerenreiner Lactole am Beispiel von Octahydro-8,9,9-trimethyl-5,8-methano-2H-1-benzopyran-2-ol (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1733-1745 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chiral Lactols, IV. Selectivities in Acetal Formation Reactions of Enantiomerically Pure Lactols using Octahydro-8,9,9-trimethyl-5,8-methano-2H-1-benzopyran-2-ol as a ModelA synthesis of the lactol 1 is described and its application as a reagent for the resolution of racemates is demonstrated in several examples. By means of X-ray and conformation analysis a general rule is given, which allows to predict the absolute configuration of acyclic alkyl-aryl-carbinols from the course of acetal formation between an enantiomerically pure lactol and the racemic alcohol.
    Notes: Eine Synthese für das Lactol 1 wird beschrieben und seine Eignung als Reagens zur Racemattrennung an einigen Beispielen gezeigt. Aufgrund einer Röntgenstruktur und konformationsanalytischer Überlegungen wird eine allgemeine Regel erarbeitet, nach welcher die Absolutkonfiguration acyclischer Alkyl-aryl-carbinole aus dem Verlauf der Acetalisierungsreaktion eines enantiomerenreinen Lactols mit dem racemischen Alkohol vorhergesagt werden kann.
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    Aufbau Germylidin-verbrückter Drei- und Vierkerncluster (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1746-1757 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Buildup of Germylidyne-bridged Tri- and Tetranuclear ClustersReaction of organogermanium trihalides with KCo(CO)4 yields the trinuclear clusters RGeCo3(CO)9 (1, R = Me, Ph, tBu) as well as the new tetranuclear clusters (RGe)2Co4(CO)11 (3, R = Ph, tBu). The dinuclear complexes LnM — GeI2 — MLn (4-6, = FeCp(CO)2, Co(CO)4, NiCpCO) resulting from insertion of GeI2 into metal-metal bonds react with KCo(CO)4 to form the clusters LnM — GeCO3(CO)9 (7-9). Metal exchange reactions produce the hetero tetranuclear clusters (tBuGe)2Co3(CO)8M′Ln = MoCp(CO)2, NiCp). Crystal structure analyses were performed for Cp(CO)2Fe — GeCo3(CO)9 (7) and (tBuGe)2Co3(CO)8NiCp (11).
    Notes: Die Umsetzung von Organogermaniumtrihalogeniden mit KCo(CO)4 liefert sowohl die Dreikerncluster RGeCo3(CO)9 (1, R = Me, Ph, tBu) als auch die neuen Vierkerncluster (RGe)2Co4(CO)11 (3, R = Ph, tBu). Die durch Insertion von Gel2 in Metall-Metall-Bindungen entstehenden Zweikernkomplexe LnM — GeI2 — MLn (4-6, MLn = FeCp(CO)2, Co(CO)4, NiCpCO) setzen sich mit KCo(CO)4 zu den Clustern LnM — GeCO3(CO)9 (7-9) um. Metallaustauschreaktionen liefern die Heterovierkerncluster (tBuGe)2Co3(CO)8M′Ln (10, 11, M′Ln = MoCp(CO)2, NiCp). Von Cp(CO)2Fe — GeCo3(CO)9 (7) und (tBuGe)2Co3(CO)8NiCp (11) wurden Kristallstrukturanalysen durchgeführt.
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    1,3-Dithienium- und 1,3-Dithioleniumsalze, II. Synthese monocyclothioacetalisierter 1,3-Diketone aus Silylenolethern (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1798-1808 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dithienium- and 1,3-Dithiolenium Salts, II. Synthesis of Monocyclothioacetalized 1,3-Diketones from Silyl Enol EthersThe 1,3-dithienium and 1,3-dithiolenium salts 3, available from the dithiols 1 or the cyclic thioacetals 4 (n = 2, 3) by reaction with the acyl chlorides 2, trityl tetrafluoroborate (5), and sulfuryl chloride (7), react in good yields with the silyl enol ethers 10 to give the new monocyclothioacetalized 1,3-Diketones 11. The synthetic of 11 as partially protected 1,3-Diketones is demonstrated exemplarily by dethioacetalization to the 1,3-dicarbonyl compounds 13.
    Notes: Die aus den Dithiolen 1 oder den cyclischen Thioacetalen 4 (n = 2, 3) durch Umsetzung mit den Acylchloriden 2, Trityl-tetrafluoroborat (5) und Sulfurylchlorid (7) erhältlichen 1,3-Dithienium-bzw. 1,3-Dithioleniumsalze 3 reagieren in guten Ausbeuten mit den Silylenolethern 10 zu den neuen monocyclothioacetalisierten 1,3-Diketonen 11. Das synthetische Potential von 11 als partiell geschützten 1,3-Diketonen wird exemplarisch durch Dethioacetalisierung zu den 1,3-Dicarbonylverbindungen 13 demonstriert.
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    Syntheses and ENDOR studies of selectively deuterated galvinoxyl radicals. Complete Determination of the 13C hyperfine coupling constants of Coppinger's radical (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1782-1797 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesen und ENDOR-Untersuchungen selektiv deuterierter Galvinoxyl-Radikale. Vollständige Bestimmung der 13C-Hyperfeinkopplungskonstanten von Coppingers RadikalDie Synthese einiger selektiv deuterierter Galvinole und deren Oxidation zu den korrespondierenden Galvinoxyl-Radikalen, z.B. Coppingers Radikal und Yangs Biradikal, wird beschrieben. Am Beispiel der Dublettradikale wird gezeigt, daß 13C-ENDOR-Spektroskopie auch ohne 13C-Isotopenanreicherung möglich ist. Im Falle von Coppingers Radikal gelang die vollständige Ermittlung der 13C-Hyperfeinkopplungskonstanten. Die ENDOR-Untersuchung von selektiv deuteriertem Yangs Biradikal in glasartiger Matrix erlaubte eine eindeutige Zuordnung der Singale zu Molekülpositionen, und es ließen sich Rückschlüsse auf die Radikalsymmetrie und die behinderte Rotation der tert-Butylgruppen ziehen. In den ENDOR-Spektren regellos orientierter Bisgalvinoxyl-Biradikale im Triplettzustand findet man scharfe Signale bei den freien Kern-Zeeman-Frequenzen, die von NMR-Übergängen im Ms = 0-Spinzustand herrühren. Es wird gezeigt, daß die betreffenden Deuterium-Signale infolge der Quadrupolwechselwirkung der Deuteriumkerne aufgespalten sind.
    Notes: The synthesis of selectively deuterated galvinols is described. Oxidation results in the formation of the respective galvinoxyl free radicals, e.g., Coppinger's radical and Yang's biradical. It is shown that 13C ENDOR signals can be detected for the doublet radicals without 13C labelling, i.e., in natural abundance. The complete set of 13C hyperfine coupling constants of Coppinger's radical could be determined. The ENDOR study of selectively deuterated Yang's biradical in a glassy matrix allowed an unambiguous assignment of the signals to molecular positions, and conclusions with respect to the symmetry of the radical and the hindered rotation of the tert-butyl groups could be drawn. Randomly oriented bisgalvinoxyl biradicals in the triplet spin state give rise to sharp ENDOR lines at the free nuclear Zeeman frequencies due to NMR transitions in the Ms = 0 electron spin manifold, and it is demonstrated that the respective 2H ENDOR lines show quadrupole splittings.
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    Darstellung von (η6-Aren)2Cr2(CO)3-Komplexen mit einer formalen Cr ≡ Cr-Dreifachbindung aus η6-ArenCr(CO)2NCCH3 (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1825-1835 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (η6-arene)2Cr2(CO)3 Complexes Containing a Formal Cr ≡ Cr Triple Bond Starting from η6-areneCr(CO)2NCCH3The photochemical reaction of η6-ArCr(CO)3 (Ar = benzene, toluene, m-xylene, mesitylene, methyl benzoate, and fluorobenzene) with acetonitrile in hexane or p-tolunitrile in THF, resp., yields complexes η6-ArCr(CO)2NCR (1 - 10). Solutions of the red acetonitrile complexes yield on warming or UV photolysis by dissoziation of the nitrile and one CO ligand in the presence of benzene the new black coordination compounds (η6-Ar)2Cr2(CO)3 (11 - 16). The spectra and an X-ray structure determination of the benzene derivative 11 verify a Cr2-unit with a formal triple bond bridged by three CO ligands. The asymmetric unit of 11 contains two halves of molecules with Cr — Cr distances of 222.6 and 221.6 pm.
    Notes: Bei der photochemischen Umsetzung von η6-ArCr(CO)3 (Ar = Benzol, Toluol, m-Xylol, Mesitylen, Benzoesäure-methylester und Fluorbenzol) mit Acetonitril in Hexan bzw. p-Tolunitril in THF entstehen Komplexe η6-ArCr(CO)2NCR (1-10). Lösungen der roten Acetonitrilkomplexe bilden in der Wärme oder bei UV-Bestrahlung unter Abspaltung des Nitril- und eines CO-Liganden in Gegenwart von Benzol die neuen schwarzen Komplexe (η6-Ar)2Cr2(CO)3 (11-16). Die Spektren und die Röntgenstrukturanalyse des Benzolderivats 11 belegen eine von drei CO-Liganden verbrückte, formal eine Dreifachbindung aufweisende Cr2-Einheit. Die asymmetrische Enheit von 11 enthält zwei Molekülhälften mit Cr — Cr-Abständen von 222.6 bzw. 221.6 pm.
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    Reaction of 1-oxa-3-azabutatrienium salts with tertiary carboxamides (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1876-1886 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktion von 1-Oxa-3-azabutatrienium-Salzen mit tertiären CarbonsäureamidenDie α-Chlorisocyanate 1 reagieren mit tertiären Carbonsäureamiden oder Acyliminen 3 in Gegenwart von Lewis-Säuren (SbCl5, FeCl3) unter milden Bedingungen zu den aminosubstituierten 2-Azaallenium-Salzen 5a - t. Die nur mäßig starken Elektrophile 5 setzen sich mit Methanol zu den Acetalen 8 und 10 um. Eine Röntgenstrukturanlyse von 5a zeigt, daß die -Einheit dieses Moleküls gewinkelt ist (128°). Es besteht eine Proportionalität zwischen der Wellenzahl der antisymmetrischen Valenzschwingung von 2-Azaallenium-Salzen und dem -Bindungswinkel. Die durch die sp2-Kohlenstoffe der -Einheit von 5a definierten Ebenen stehen nahezu senkrecht (84°) aufeinander.
    Notes: α-Chloro isocyanates 1 react with tertiary carboxamides or acylimines 3 in the presence of Lewis acids (SbCl5, FeCl3) to give the amino-substituted 2-azaallenium salts 5a - t under mild conditions. With methanol the moderately strong electrophiles 5 afford the acetals 8 and 10. According to an X-ray structural analysis, the C = N = C unit of 5a is bent by 128°. There exists a linear relationship between the wave number of the antisymmetric stretching vibration of 2-azaallenium salts and the bond angle. The planes defined by the sp2 carbons of the moiety of 5a are almost perpendicular (84°) with respect to each other.
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    URL: http://dx.doi.org/10.1002/cber.19851180513
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    Bildung von Oxetanen bei der photosensibilisierten Oxidation von Enaminen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1927-1935 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation of Oxetanes via Photo-sensitized Oxidation of EnaminesPhotooxidations of the enamines 1 and 5 in toluene give rise to the formation of the usual reaction products. In methanol, however, the oxetanes 8 and 13, respectively, are isolated as the main photooxidation products. Both the mechanism of their formation as well as some reactions of 8 and 13 are discussed. Oxidation of 13 with m-chloroperbenzoic acid produces the aldehyde 15 via a multi-step reaction.
    Notes: Die Photooxidation der Enamine 1 bzw. 5 in Toluol liefert die erwarteten Reaktionsprodukte. In Methanol entstehen dagegen die Oxetane 8 bzw. 13 als Hauptprodukt der Photooxidation. Die Reaktionen dieser Verbindungen werden beschrieben. Die Oxidation von 13 mit m-Chlorperbenzoesäure führt über einen mehrstufigen einheitlichen Reaktionsablauf zum Aldehyd 15. Der Bildungsmechanismus der Oxetane 8 und 13 wird diskutiert.
    Type of Medium: Electronic Resource
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    Die Elektronenstruktur von 1,4-disubstituierten Butantetronen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1917-1926 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Electronic Structure of 1,4-Disubstituted ButanetetronesThe He(I) photoelectron (PE) spectra of the disubstituted butanetetrones 1 a - e have been recorded. The assignment of the first PE bands is based on semiempirical calculations. For 1 a - e the first bands could be assigned to ionization events from lone pair combinations on the oxygen atoms and in the case of 1 b - e additionally to ionizations from π-orbitals localized on the aromatic rings. The comparison between the PE bands of 1 d, 1,3-diphenyl-1,2,3-propanetrione, benzil, and benzophenone yields the result that the energy split between the n-orbital energies con-verges towards a value of about 3 eV. The interactions among the lone pairs and between lone pairs and the σ frame in 2 b - d are discussed, based on INDO calculations using localized orbitals.
    Notes: Die He(I)-Photoelektronen(PE)-Spektren der 1,4-disubstituierten Butantetrone 1 a - e wurden gemessen und anhand semiempirischer Rechnungen zugeordnet. Bei 1 a - e wurden die ersten Banden Ionisationen aus Linearkombinationen der einsamen Elektronenpaare an den Sauerstoffen und im Fall von 1 b - e noch zusätzlich Ionisationen aus den aromatischen π-Orbitalen zugeordnet. Der Vergleich zwischen den PE-Banden von 1 d, 1,3-Diphenyl-1,2,3-propantrion, Benzil und Benzophenon zeigt, daß die Aufspaltung zwischen den n-Orbitalenergien einem Grenzwert von etwa 3 eV zustrebt. Die Wechselwirkung zwischen den n-Orbitalen, den n-Orbitalen und dem σ-Gerüst (Through-Space- und Through-Bond-Wechselwirkung) in den vic. Di-, Tri- und Tetra-ketonen 2 b - d wird anhand von lokalisierten Orbitalen, die nach der INDO-Methode erhalten werden, diskutiert.
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    Azaborolinyl-Komplexe, XVI. Synthese und Untersuchung von (1,2-Azaborolinyl)tricarbonyl-Komplexen des Chroms, Molybdäns und Wolframs (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1949-1958 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azaborolinyl Complexes, XVI. Synthesis and Investigation of (1,2-Azaborolinyl)tricarbonyl Complexes of Chromium, Molybdenum, and Tungsten1-tert-Butyl-2-methyl-1,2-azaborolinyllithium reacts with the hexacarbonyls of chromium, molybdenum, and tungsten to give the complex salts Li[(Ab)M(CO)3] (Ab = azaborolinyl ligand, M = Cr (2), Mo (3), and W (4)). With Me3ECl (E = Ge, Sn, Pb) they form the corresponding germyl, stannyl, and plumbyl derivatives. The molecular and crystal structures of (Ab)(CO)3Cr—SnMe3 (2b) and (Ab)(CO)3Mo—SnMe3 (3b) show the azaborolinyl rings to be pentahapto-bonded, inspite of a small folding of the rings, leading to a longer distance of the boron atoms to the metal atoms. The IR, 1H, 11B, and 13C NMR data prove equivalent structures for the other complexes. The existence of enantiomers in the cell results from the crystal structure investigations of 2b and 3b and is caused by the prochiral character of the azaborolinyl rings.
    Notes: 1-tert-Butyl-2-methyl-1,2-azaborolinyllithium reagiert mit den Hexacarbonylen von Chrom, Molybdän und Wolfram zu den komplexen Salzen Li[(Ab)M(CO)3] (Ab = Azaborolinyl-Ligand, M = Cr (2), Mo (3) und W (4)). Diese bilden mit Me3ECl (E = Ge, Sn, Pb) die entsprechenden Germyl-, Stannyl- und Plumbylderivate. Die Molekül- und Kristallstrukturen von (Ab)(CO)3Cr—SnMe3 und (2b) und (Ab)(CO)3Mo—SnMe3 (3b) weisen die Azaborolinylringe als pentahapto-gebunden aus, trotz einer leichten Faltung der Ringe, durch die die Boratome einen größeren Abstand zu den Metallatomen erreichen. Die IR-, 1H-, 11B- und 13C-NMR-Daten beweisen äquivalente Strukturen für die übrigen Komplexe. Aus den Kristallstrukturuntersuchungen von 2b und 3b geht die Anwesenheit von Enantiomeren in der Zelle hervor, verursacht durch den prochiralen Charakter der Azaborolinylringe.
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    URL: http://dx.doi.org/10.1002/cber.19851180519
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    2,4-Diazabicyclo[3.3.1]nonan-Gerüste aus cis-Benzoltrioxid (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2044-2078 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2,4-Diazabicyclo[3.3.1]nonane Skeletons from cis-Benzene TrioxideBy treating cis-benzene trioxide (1) with guanidine in buffered tert-butyl alcohol solution the 1:1-adducts DL-(1α,2β,4β,5α,6α,10α)- 8-imino-3-oxa-7,9-diazatricyclo[4.3.1.02,4]decane-5,10-diol (13a) and DL-(1α,2α,3β,5β,6α,7α)- 9-imino-4-oxa-8,10-diazatricyclo[5.3.0.03,5]decane-2,6-diol (12a) resulting from 1,3(1,2)-bridging in 1 are obtained in 88 - 91% (9 - 12%) yields. Trifluoroacetamidine (acetamidine) is also selectively 1,3-added to 1. From 13a via generally regiospecific hydrolysis (26a), thiolysis (30a, d) ammonolysis (34a), hydrazinolysis (34d), and HCl-/HBr- addition (39a, c) access to highly functionalised 2,4-diazabicyclo[3.3.1]nonane derivatives is opened. During the “ring-chain tautomerism” observed for 26a and 34d (28a, 36d) the adamantoid orthocarbonic acid intermediates (27a, 35d) cannot be identified directly. The spectroscopic structure elucidations (not always unequivocal because i.a. of conformational flexibility of the skeletons) are confirmed by X-ray structural analysis for 29f, 36e, 38, und 43.
    Notes: Bei der Umsetzung von cis-Benzoltrioxid (1) mit Guanidin in gepufferter tert-Butylalkohol-Lösung werden mit 88 - 91% (9 - 12%) Ausbeute die aus der 1,3(1,2)-Überbrückung in 1 hervorgehenden 1:1-Addukte DL-(1α,2β,4β,5α,6α,10α)- 8-Imino-3-oxa-7,9-diazatricyclo[4.3.1.02,4]decan5,10-diol (13a) und DL-(1α,2α,3β,5β,6α,7α)- 9-Imino-4-oxa-8,10-diazatricyclo[5.3.0.03,5]decan-2,6-diol (12a) gewonnen. Auch Trifluoracetamidin (Acetamidin) wird an 1 bevorzugt 1,3-addiert. Aus 13a gewinnt man durch jeweils regiospezifische Hydrolyse (26a), Thiolyse (30a, d), Ammonolyse (34a), Hydrazinolyse (34d) und HCl/HBr-Addition (39a, c) Zugang zu hochfunktionalisierten 2,4-Diazabicyclo[3.3.1]nonan-Derivaten. Bei der für 26a und 34d beobachteten „Ring-Ketten-Tautomerie“ (28a, 36d) sind die adamantoiden Orthokohlensäure-Intermediate (27a, 35d) nicht nachweisbar. Die u. a. wegen der konformativen Flexibilität der Gerüste nicht immer eindeutigen spektroskopischen Strukturzuordnungen werden durch Röntgenstrukturanalysen für 29f, 36e, 38 und 43 gesichert.
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    Untersuchungen an Diazoverbindungen und Aziden, 58. Dikation-ether, 5. Formamidinium-substituierte Diazophosphoryl-Verbindungen: Synthese, Eigenschaften und Reaktionen zu Tetrazolen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2105-2117 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on Diazo Compounds and Azides, 58. Dication Ethers, 5. Formamidinium-substituted Diazophosphoryl Compounds: Synthesis, Properties, and Reactions Leading to TetrazolesElectrophilic diazoalkane substitution of diazophosphoryl compounds 4a - c by bis(formamidinium) ethers 3a, b leads to formamidinium-substituted (diazomethyl)phosphoryl compounds 5. These can also be considered as alkenediazonium salts, but the contribution from this resonance structure is low according to 1H NMR and IR data. Reaction of 5a - c with another equivalent of 4a - c under slightly modified conditions yields 2-vinyl-2H-tetrazoles 6 and 7. The identity of the tetrazoles has been confirmed by X-ray structure analysis of 6c as well as by thermolysis of 6c leading to pyrazole 12 which then was hydrolyzed to give the NH-pyrazole 13.
    Notes: Die Diazophosphoryl-Verbindungen 4a - c reagieren mit den Bis(formamidinium)ethern 3a, b im Sinne einer elektrophilen Diazoalkan-Substitution zu Formamidinium-substituierten (Diazomethyl)phosphoryl-Verbindungen 5. Diese lassen sich auch als Olefindiazoniumsalze auffassen, jedoch deuten 1H-NMR- und IR-Daten nur auf einen geringen Anteil dieses Bindungszustandes hin. Unter leicht modifzierten Reaktionsbedingungen reagieren 5a - c mit einem weiteren Äquivalent von 4a - c zu den 2-Vinyl-2H-tetrazolen 6 und 7. Die Identität der Tetrazole wird durch eine Röntgenstrukturanalyse von 6c sowie die Thermolyse von 6c zum Pyrazol 12 und dessen Hydrolyse zum NH-Pyrazol 13 belegt.
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    The molecular and electronic structure of dipiperidinosquaraine (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2118-2126 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Molekulare und elektronische Struktur von DipiperidinoquadratainDipiperidinoquadratain (9) kristallisiert im orthorhombischen Gitter, Raumgruppe Pnab, mit 4 Molekülen in einer Elementarzelle mit den Abmessungen a = 7.1798(9), b = 9.5362(8) und c = 18.788(2) Å. Das Molekül liegt auf einem Symmetriezentrum, d.h. der Vierring (C — C = 1.456(1) Å) ist genau planar; die Stickstoff- und Sauerstoffatome sind fast mit dem Ring coplanar, mit C — O = 1.2396(7) und C — N = 1.3112(7) Å. Sowohl die experimentellen als auch die theoretischen Daten zeigen beachtliche C — N- und C — O-π-Bindungen, aber nur eine geringfügige C — C-π-Bindung im Quadratainsystem. Die Berechnungen ergeben starke 1,3-abstoßende Wechselwirkungen im Vierring. Ringfaltung, ein sonst üblicher Mechanismus bei der Vermeidung solcher Abstoßungen, wird hier durch die starke C — N-π-Bindung verhindert.
    Notes: Dipiperidinosquaraine (9) crystallizes in the orthorhombic system, space group Pnab, with four molecules in a cell of dimensions a = 7.1798(9), b = 9.5362(8), and c = 18.788(2) Å. The molecule is located over a center of symmetry, so the four-membered ring (C - C = 1.456(1) Å av) is exactly planar; the nitrogen and oxygen atoms are nearly coplanar with the ring, with C — O = 1.2396(7) and C — N = 1.3112(7) Å. Both experimental and theoretical evidence indicates the presence of considerable C — N and C — O π-bonding, but only a small amount of C — C π-bonding in the squaraine system. The calculations indicate the presence of strong 1,3-repulsive interactions within the four-membered ring. Ring puckering, which is a common mechanism to alleviate these repulsions, is prevented here by the extensive C — N π-bonding.
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    The He(Iα) PE spectra and electronic absorption spectra of hexafluorocyclobutanone and of tetrafluoro-1,2-cyclobutane-dione (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2127-2133 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die He(Iα)-PE-Spektren und Elektronenabsorptionsspektren von Hexafluorcyclobutanon und Tetrafluor-1,2-cyclobutandionDie He(Iα)-PE-Spektren und die Elektronenabsorptionsspektren von Hexafluorcyclobutanon (3) und Tetrafluor-1,2-cyclobutandion (4) wurden gemessen. Die Zuordnung der ersten Banden beider Spektrentypen basiert hauptsächlich auf der Korrelation mit den entsprechenden Spektren der unsubstituierten Verbindungen Cyclobutanon (1) und 1,2-Cyclobutandion (2) sowie auf den Resultaten semiempirischer Rechnungen. Die Banden in den PE-Spektren von 3 und 4 werden im Vergleich zu den PE-Banden von 1 und 2 durch den Perfluor-Effekt um 1.6 bzw. 1.5 eV zu höheren Energien verschoben. Vergleicht man die Energie der ersten Bande in den Elektronenspektren von 1 und 3 bzw. 2 und 4, so findet man, daß diese Bande bathochrom um etwa 5000 cm-1 durch die Perfluor-Substitution verschoben wird. Dies wird dadurch erklärt, daß beim Ersatz der H-Atome durch F-Atome die Energie des LUMOs (π*) stärker abgesenkt wird als die des HOMOs (n).
    Notes: The He(Iα) PE and the electronic absorption spectra of hexafluorocyclobutanone (3) and tetrafluoro-1,2-cyclobutanedione (4) have been recorded. The assignment of the observed bands in both types of spectra is mainly based on the correlation with the corresponding spectra of the parent compounds cyclobutanone (1) and 1,2-cyclobutanedione (2), and in addition on the results of semiempirical calculations. As a result of the perfluoro effect, the bands in the PE spectra of 3 and 4 are shifted towards higher ionization energies by 1.6 eV and 1.5 eV relative to the corresponding bands in the PE spectra of 1 and 2. A comparison of the positions of the first band in the electronic spectra of 1 and 3, as well as of 2 and 4, shows that this band is shifted bathochromically by about 5000 cm-1 as a consequence of the perfluoro substitution. This is explained as being due to a stronger lowering of the LUMO (π*) energy than that of the HOMO (n) energy, induced by the replacement of the H-by F-atoms.
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    Cycloadditionen des 1-(4-Methoxyphenyl)-2,2-dimethylvinyl-Kations an Olefine (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2974-2992 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions of 1-(4-Methoxyphenyl)-2,2-dimethylvinyl Cation to Olefins1-Bromo-1-(4-methoxyphenyl)-2-methyl-1-propene (1) reacts with cyclohexene, cycloheptene, (Z)-cyclooctene and the silver salts AgBF4, via the vinyl cation 2 by cycloaddition to form the cyclobutenes 7b-d. Cyclobutene 8 is obtained from (Z)- and (E)- and (E)-2-butene. Besides the cyclobutene derivatives, the isomeric cyclopropane compound 10d is also formed in the reaction of 1 with (Z)-cyclooctene under the same conditions, with cyclopentene only the cyclopropane derivative is formed. Copper (I) triflate-olefin complexes can be used in place of silver slats to generate the vinyl cation 2, whereby cyclobutenes 7 are formed preferably. - In contrast to vinyl bromide 1, 1-(4-methoxyphenyl)-2-methyl-1-propenyl triflate (5) reacts with cyclopentene, cyclohexene, cyloheptene, (Z)- and (E)-cyclooctene to give mostly the corresponding cyclopropane derivatives 10. The stereoisomeric cyclopropyl compounds 19 are obtained from (Z)- and (E)-2-butene. - The mechanisms of silver-catalysed and silver-free cycloaddition reactions are discussed.
    Notes: 1-Brom-1-(4-methoxyphenyl)-2-methyl-1-propen (1) reagiert mit Cyclohexen, Cyclohepten, (Z)-Cycloocten und den Silbersalzen AgBF4 bzw. AgSbF6 über das Vinylkation 2 unter Cycloaddition überwiegend zu den Cyclobutenen 7b-d. Mit (Z)- und (E)-2- Buten wird das Cyclobuten 8 erhalten. Bei der Umsetzung von 1 unter den gleichen Bedingungen entsteht mit Cyclopenten das Cyclopropanderivat 10a, mit (Z)-Cycloocten entsteht neben dem Cyclobutenderivat 7d die isomere Cyclopropanverbindung 10d. An Stelle der Silbersalze können auch Kupfer(I)-triflat-Olefin-Komplexe zur Erzeugung des Vinylkations 2 verwendet werden, wobei ebenfalls bevorzugt die Cyclobutene 7 erhalten werden. - Im Gegensatz zum Vinylbromid 1 reagiert das 1-(4-Methoxyphenyl)-2-methyl-1-propenyl-triflat (5) mit Cyclopenten, Cyclohexen, Cyclohepten und (Z)- bzw. (E)-Cycloocten überwiegend zu den entsprechenden Cyclopropanderivaten 10. Mit (Z)- und (E)-2-Buten werden die stereoisomeren Cyclopropylverbindungen 19 erhalten. - Die Mechanismen der silbersalzkatalysierten und silberfreien Cycloadditionsreaktionen werden diskutiert.
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    Basische Metalle, LVI Reaktionen von (Pentamethylcyclopentadienyl)rhodium(I)-Komplexen mit Dihalogen- und Trihalogenmethanen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3032-3040 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Basic Metals, LVI. Reactions of (Pentamethylcyclopentadienyl)rhodium(I) Complexes with Dihalo- and TrihalomethanesC5Me5Rh(CO)2 and C5Me5Rh(CO)L (L=PMe3, PMe2Ph, P(OMe)3) react with dihalo- and trihalomethanes to give (pentamethylcyclopentadienyl)rhodium complexes containing CH2X and CHX2 (X=Cl, Br, I, CN) as ligands. The reactions of [C5Me5RhCH2I(L)I] (L=CO, PMe3) with NaOCH3, PMe3, and PPh3 lead in some cases to substitution (e.g., formation of [C5Me5RhCH2OMe(PMe3)I] and [C5Me5Rh(CH2PPh3)(PMe3)I]X), in some cases to cleavage of the Rh - C bond. [C5Me5RhCH2I(CO)I] reacts with CH2(PPh2)2 to form the cyclic ylide complex [Ph2(I)]I.
    Notes: Durch Reaktion von C5Me5Rh(CO)2 und C5Me5Rh(CO)L (L=PMe3, PMe2Ph, P(OMe)3) mit Dihalogen- und Trihalogenmethanen werden (Pentamethylcyclopentadienyl)rhodium-Komplexe mit CH2X und CHX2 (X=Cl, Br, I, CN) als Liganden synthetisiert. Die Umsetzungen von [C5Me5RhCH2I(L)I] (L=CO, PMe3) mit NaOCH3, PMe3 und PPh3 verlaufen teilweise unter Substitution (Bildung z.B. von [C5Me5RhCH2OMe(PMe3)I] und [C5Me5Rh(CH2PPh3)(PMe3)I]X), teilweise aber auch unter Spaltung der Rh - C-Bindung. [C5Me5RhCH2I(CO)I] reagiert mit CH2(PPh2)2 zu dem cyclischen Yild-Komplex [Ph2(I)]I.
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    Monoozonolysen von acyclischen konjugierten Dienen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3041-3057 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Monoozonolyses of Acyclic Conjugated DienesMonoozonolyses of isoprene (1a), 2-methyl-3-phenyl-1,3-butadiene (1b), 2,3-diphenyl-1,3-butadiene (25), and 2,3,4,5-tetramethyl-2,4-hexadiene (34) have been examined in pentane and in methanol. The dienes 1a, b and 25 afforded all possible α,β-unsaturated monoozonides and α,β-unsaturated methoxy hydroperoxides, respectively, whereas diene 34 gave no ozonide and no α,β-unsaturated methoxy hydroperoxide. From the dienes 25 and 34, the corresponding monoepoxides have been formed additionally. The results allow some conclusions concerning the regioselectivity of ozone attack at the unsymmetrically substituted dienes 1a, b as well as concerning the cleavage directions of primary ozonides.
    Notes: Monoozonolysen von Isopren (1a), 2-Methyl-3-phenyl-1,3-butadien (1b), 2,3-Diphenyl-1,3-butadien (25) und 2,3,4,5-Tetramethyl-2,4-hexadien (34) in Pentan und in Methanol wurden untersucht. Die Diene 1a, b und 25 lieferten alle möglichen α,β-ungesättigten Monoozonide bzw. α,β-ungesättigten Methoxyhydroperoxide; das Dien 34 ergab kein Ozonid und kein α,β-ungesättigtes Methoxyhydroperoxid. Aus den Dienen 25 und 34 wurden zusätzlich auch die entsprechenden Monoepoxide erhalten. Die Ergebnisse erlauben Rückschlüsse auf die Regioselektivität des Ozonangriffes an den unsymmetrisch substituierten Dienen 1a, b sowie über die Spaltungsrichtungen von Primärozoniden.
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    Photolyse des 9-Azidotriptycens. - Struktur des Dimeren eines extrem gespannten Brückenkopfimins (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 3058-3069 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photolysis of 9-Azidotriptycene. - Structure of the Dimer of a Severely Strained Bridgehead IminePhotolysis of 9-azidotriptycene (4) in cyclohexane affords molecular nitrogen and a dimer of the intermediate bridgehead imine 5 in 69% yield. The dimer is very sensitive towards traces of acid and irradiation in the presence of oxygen. The structure of the dimer is elucidated by spectroscopic methods as well as by an X-ray diffraction analysis. In solution approximately equal amounts of the (racemic) diastereomers 10 A and B are present which interconvert via an energy barrier of ΔG413≠ = ca. 90 kJ · mol-1. In contrast, in the crystalline state only diastereomer 10 A exists. The distereomer 10 A crystallizes as a racemate in the monoclinic space group P21/n (No. 14) with four molecules per cell. As the first step in the formation of 10 A, B we assume a dimerization of the bridgehead imine 5 producing 12 which rearranges to 10 A, B via a proton shift (→13) and subsequent opening of one of the 4H-azepine rings. The results are indicative of some diradical character of the bridgehead imine 5.
    Notes: Die Photolyse des 9-Azidotriptycens (4) in Cyclohexan ergibt neben Stickstoff mit 69% Ausbeute ein Dimeres des intermediären Brückenkopfimins 5. Das Dimere ist sehr empfindlich gegen Säurespuren und Belichten in Gegenwart von Luftsauerstoff. Die Struktur des Dimeren wird spektroskopisch und durch Röntgenbeugungsanalyse aufgeklärt. In Lösung liegen etwa gleiche Mengen der Diastereomeren 10 A und B vor, die sich mit ΔG413≠ =ca. 90 kJ · mol-1 ineinander umwandeln. Im Kristall existiert dagegen nur das Diastereomere 10 A, das als Racemat monoklin in der Raumgruppe P21/n (Nr. 14) mit vier Molekülen in der Elementarzelle kristallisiert. Als ersten Schritt der Bildung von 10 A, B nehmen wir eine Dimerisierung des Brückenkopfimins 5 zu 12 an, das sich durch Protonenwanderung (→13) und Öffnung eines 4H-Azepinrings in 10A, B umlagert. Die Ergebnisse sprechen für einen gewissen Diradikalcharakter des Brückenkopfimins 5.
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    Über sterisch gehinderte freie Radikale, XII. Das Radikal tert-Butyldiphenylmethyl, sein Dimeres sowie deren Autoxidation. Eine Neuuntersuchung (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 450-456 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sterically Hindered Free Radicals, XII. The Radical tert-Butyldiphenylmethyl, Its Dimer, and Their Autoxidation. A ReinvestigationThe radical Ph2C.  -  tBu (1) dimerizes giving reversibly the quinonoid derivative 3, and not the ethane-like 2 as reported in the literature. In equilibrium there are less radicals 1 than in the case of triphenylmethyl, ΔHdiss = 18.5 ± 2 kcal/mol for 3. Both the radical 1 and its dimer 3 are rapidly oxidized by oxygen. 1 gives the dialkyl peroxide 6 which fragmentates already at 20°C mainly to benzophenone and tBu., 3 leads to the ketone 7, probably via the hydroperoxide 10. 3 rearranges catalysed by acid and by base as well via a 1,5-hydrogen migration forming the benzenoid derivative 4. Preparative and ESR details are given.
    Notes: Das Radikal Ph2C.  -  tBu (1) dimerisiert reversibel zum chinoiden Derivat 3 und nicht zum ethan-artigen 2, wie in der Literature berichtet. Im Gleichgewicht liegt weniger Radikal 1 vor als im Fall von Triphenylmethyl, ΔHDiss = 18.5 ± 2 kcal/mol für 3. Sowohl das Radikal 1 wie sein Dimeres 3 werden durch Sauerstoff rasch oxidiert. 1 gibt das Dialkylperoxid 6, das schon bei 20°C fragmentiert, hauptsächlich zu Benzophenon und tBu., 3 führt zum Keton 7, wahrscheinlich über das Hydroperoxid 10. 3 lagert sich, sowohl säure- wie basenkatalysiert, unter 1,5-H-Verschiebung um in das benzoide Derivat 4. Einzelheiten zu den Darstellungen sowie zur ESR-Spektroskopie werden angegeben.
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    Beiträge zur Chemie des Bors, 146. Über die Reaktion von Tetrazadiborinanen mit Heterokumulenen: Pseudodipolare [2 + 3]-Cycloadditionen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 483-494 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 146 Reactions of Tetrazadiborinanes with Heterocumulenes: Pseudodipolar [2 + 3]-CycloadditionsCO2, COS, and CS2 scavenge the 1,3-dipolar unit \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm R'}\mathop {{\rm B - }}\limits^ \oplus {\rm NR - }\mathop {\rm N}\limits^{\rm \Theta } {\rm R} $\end{document} from the tetrazadiborinanes 3. [2 + 3]-Cycloadducts are formed in a pseudodipolar reaction, namely oxadiaza- and thiadiazaborolidines of type 7, 8 and 4. A reaction mechanism is suggested.  -  The thiadiazaborolidine 4b contains a planar five-membered ring according to an X-ray structure determination. Short BN, NN, and CN bond distances suggest a heteroaromatic ring system. High polarity is associated with the thioxo group. In contrast, the oxadiazaborolidinones 8a, b are in an equilibrium with their dimers in solution.
    Notes: CO2, COS und CS2 fangen aus den Tetrazadiborinanen 3e) den 1,3-Dipol \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm R'}\mathop {{\rm B - }}\limits^ \oplus {\rm NR - }\mathop {\rm N}\limits^{\rm \Theta } {\rm R} $\end{document} ab. In einer pseudodipolaren Reaktion bilden sich als [2 + 3]-Cycloaddukte die Oxadiaza- und Thiadiazaborolidine 7, 8 und 4. Ein Reaktionsmechanismus wird diskutiert.  -  Nach Röntgenstrukturanalyse enthält 4b einen planaren Fünfring. Kurze BN-, NN- und CN-Abstände legen ein heteroaromatisches System nahe, wobei der Thioxo-Gruppe eine erhebliche Polarität zuzuweisen ist. Die Oxadiazaborolidinone 8a, b stehen in Lösung im Gleichgewicht mit ihrem Dimeren.
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    The colour of chelates of boron. An X-ray structural investigation of bis(4-methylphenyl)boryl and 9-borabicyclo-[3.3.1]nonyl acetylacetonates (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 670-675 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Farbe von Bor-Chelaten. Röntgenstruktur-Untersuchung von Bis(4-methylphenyl)boryl- und 9-Borabicyclo[3.3.1]nonyl-acetylacetonatenDie Molekülstrukturen des farblosen Bis(4-methylphenyl)boryl- und des orangefarbenen 9-Borabicyclo[3.3.1]non-9-yl-acetylacetonats (4 und 5) wurden durch Röntgenstrukturanalyse ermittelt. Die C—O-Abstände in 4 sind merklich (ca. 0.029 Å) länger als die in 5. Es wird vermutet, daß der unterschiedliche π-Charakter in den C—O-Bindungen die Verschiebungen im Elektronenspektrum der verschiedenen Chelate von 1,3-Diketonen und verwandten Verbindungen verursacht.
    Notes: The molecular structures of the colourless bis(4-methylphenyl)boryl and the orange coloured 9-borabicyclo[3.3.1]non-9-yl acetylacetonates (4 and 5, respectively) have been determined by X-ray analysis. The C—O bond lengths in 4 are significantly (about 0.029 Å) longer than in 5. It is suggested that variation of the π bond order in the C—O bonds is responsible for the shifts in the electronic spectra observed for the various chelates of 1,3-diketones and related compounds.
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    2-Azaallenium salts from the reaction of 1-oxa-3-azabutatrienium salts with cyanamides and carbodiimides (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1887-1902 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung von 2-Azaallenium-Salzen durch Reaktionen von 1-Oxa-3-azabutatrienium-Salzen mit Cyanamiden und CarbodiimidenDie 1-Oxa-3-azabutatrienium-Salze 2 reagieren mit disubstituierten Cyanamiden unter [2 + 2 + 2]-Cycloaddition zu den 2-(Alkylidenamino)-4,6-diamino-1,3,5-oxadiazinium-Salzen 7a - o, die man als oxysubstituierte 2-Azaallenium-Salze betrachten kann. Durch Anlagerung von Methanol entstehen die Oxadiazinium-Salze 8a, d, p. Aus 2n und Dimethylcyanamid erhält man das 2-Azaallenium-Salze 11, dessen Bildung eine [1,5]-isocyanatotrope Umlagerung einschließt. Die Butatrienium-Salze 2 reagieren meist mit zwei Äquivalenten Carbodiimid vom Typ R1 — N = C = N — CHR22 zu den 2-Azaallenium-Salzen 17a - k, die durch eine [1,5]-Hydridverschiebung entstehen. Sterisch anspruchsvoll substituierte Butatrienium-Salze 2 lagern drei Moleküle Diisopropylcarbodiimid and und ergeben die 1,3,5-Triazinium-Salze 20n, o. Es werden Röntgenstruktur-analysen der Verbindungen 7a und 17a angegeben.
    Notes: 1-Oxa-3-azabutatrienium salts 2 react with disubstituted cyanamides under [2 + 2 + 2] cycloaddition affording the 2-(alkylideneamino)-4,6-diamino-1,3,5-oxadiazinium salts 7a - o, which can be regarded as oxy-substituted 2-azaallenium salts. Addition of methanol leads to the oxadiazinium salts 8a, d, p. From 2n and dimethylcyanamide the 2-azaallenium salt 11 was obtained, which must be formed by an [1,5] isocyanatotropic rearrangement. Most butatrienium salts 2 react with two equivalents of carbodiimides R1 — N = C = N — CHR22 to form the 2-azaallenium salts 17a - k. The reaction mechanism includes an [1,5] hydride shift. Bulky substituted butatrienium salts 2 add three molecules of diisopropylcarbodiimide to give the 1,3,5-triazinium salts 20n, o. X-Ray structural analyses for 7a and 17a are reported.
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    Iminokohlenstoff-Dianionen der C4-Reihe mit Cyaniminofunktionen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1903-1916 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Iminocarbon Dianions of the C4-Series with Cyanoimino GroupsSuitable activated squaric acid derivatives react with the anion of cyanamide to yield novel iminocarbon dianions of the C4-series 8 - 11, in which the oxygens of the squarate dianion are successively replaced by one, two, three, or four cyanoimino groups. Besides the synthesis of mixed substituted iminocaron monoanions such as 12, 13, 25, and 26 is described. Spectroscopic data are discussed, 13C NMR data are compared with those of other pseudooxocarbons of the C3- and C4-series. The structure of the first isolable C4-iminocarbon 11′ is proved by X-ray diffraction, which confirmed 11′ to be a delocalized bond system just like the squarate dianion or the other pseudooxocarbons of the C4-series.
    Notes: Geeignet aktivierte Quadratsäurederivate lassen sich mit dem Anion des Cyanamids zu neuen Iminokohlenstoff-Dianionen der C4-Reihe 8 - 11 umsetzen, in denen die Sauerstoffunktionen des Quadratats sukzessive durch ein, zwei, drei oder vier Cyaniminogruppen ersetzt sind. Daneben wird die Darstellung gemischt substituierter Iminokohlenstoff-Monoanionen wie 12, 13, 25 und 26 beschrieben. Spektroskopische Daten werden diskutiert, 13C-NMR-Daten mit denen anderer Pseudooxokohlenstoffe der C3- und C4-Serie verglichen. Die Konstitution des ersten isolierbaren C4-Iminokohlenstoffs 11′ wird durch eine Röntgenstrukturanalyse belegt, die bestätigt, daß 11′ analog dem Quadratat und den anderen Pseudooxokohlenstoffen der C4-Reihe ein delokalisiertes Bindungssystem besitzt.
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    Anisotropieeffekte konjugierter cyclischer Systeme, VI. Struktur und magnetische Anisotropie mesitylsubstituierter Ferrocene (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1968-1982 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Anisotropy Effects of Conjugated Cyclic Systems, VI. Structure and Magnetic Anisotropy of Mesityl-substituted FerrocenesTwo isomeric ferrocene derivatives have been obtained from 2-(2-ethyl-4,6-dimethylphenyl)-1,3-dimethylcyclopentadiene (22a). The exo,exo- (9) as well as the endo,endo-configuration (10) of these were determined by X-ray structure analysis. The assignment of the 1H NMR signals of the methyl groups in the spectrum of 1,1′,3,3′-tetramethyl-2,2′-dimesitylferrocene (7) is derived from the spectra of 9 and 10. Signals of methyl groups in exo-position of the mesitylferrocene are shifted by -0.74 ppm to higher magnetic field. Signals of methyl groups in endo-position directed towards the iron atom are shifted downfield by +0.71 ppm. Therefore, ferrocene develops a diamagnetic anisotropy which is similar to that of benzene.
    Notes: Aus 2-(2-Ethyl-4,6-dimethylphenyl)-1,3-dimethylcyclopentadien (22a) werden zwei isomere Ferrocenderivate erhalten. Durch Röntgenstrukturanalysen wird deren exo,exo-(9) bzw. endo,endo-Konfiguration (10) bestimmt. Anhand der 1H-NMR-Spektren dieser Ferrocene ist die Zuordnung der Methylgruppensignale im 1H-NMR-Spektrum des 1,1′,3,3′-Tetramethyl-2,2′-dimesitylferrocens (7) bewiesen. Signale von Methylgruppen in exo-Stellung des Mesitylferrocens werden um -0.74 ppm nach hohem Magnetfeld und solche von zum Eisenatom gerichteten in endo-Stellung um +0.71 ppm nach tiefem Feld verschoben. Daraus leitet sich für Ferrocen eine dem Benzol ähnliche diamagnetische Anisotropieverteilung ab.
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    Synthese und Struktur von Lithiumkomplexen mit pentahapto-gebundenen Tris(trimethylsilyl)cyclopentadienyl-Liganden (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1959-1967 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of Lithium Complexes with pentahapto-Bonded Tris(trimethylsilyl)cyclo-pentadienyl LigandsReaction of tris(trimethylsilyl)cyclopentadienyllithium (2) with the nitrogen bases quinuclidine, tetramethylethylenediamine, and pentamethyldiethylenetriamine leads to the isolation of the crystalline, air-sensitive 1:1-adducts 3, 4, and 5, resp., which are monomeric in the gas phase, in solution, and in the solid state. X-Ray structure determinations show that in 3-5 the cyclopentadienyl ring is pentahapto-bonded to the lithium atom. The bonding in these π-complexes is discussed; the complex 3 fulfills the criteria for a nido-cluster.
    Notes: Umsetzung von Tris(trimethylsilyl)cyclopentadienyllithium (2) mit den Stickstoffbasen Chinuclidin, Tetramethylethylendiamin und Pentamethyldiethylentriamin führt zur Isolierung der kristallinen, luftempfindlichen 1:1-Addukte 3, 4 und 5, die in der Gasphase, in Lösung und im festen Zustand monomer vorliegen. Kristallstrukturuntersuchungen zeigen, daß in 3-5 der Cyclopentadienylring pentahapto an das Lithiumatom gebunden ist. Die Bindungsverhältnisse in diesen π-Komplexen werden diskutiert; der Komplex 3 erfüllt die Kriterien für einen nido-Cluster.
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    Selektive Reduktion von Cyclohexadienonen mit Fe2(CO)9 und Wasser (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1983-1995 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Selective Reduction of Cyclohexadienones with Fe2(CO)9 and waterSelective monohydrogenation of cross conjugated 2,5-cyclohexadien-1-ones 1 with Fe2(CO)9 and water forming under unusually mild conditions the cyclohexadienol complexes 2 is applied to various related compounds. The regioselectivity of this reaction is tested with differently substituted derivatives. A mechanism explaining the observed regioselectivities and the pH dependence of the stereochemistry is discussed.
    Notes: Die unter ungewöhnlich milden Bedingungen verlaufende selektive Monohydrierung gekreuzt konjugierter 2,5-Cyclohexadien-1-one 1 mit Fe2(CO)9 und Wasser zu den Cyclohexadienol-Komplexen 2 wird auf verschiedene verwandte Verbindungen übertragen. Die Regioselektivität der Reaktion wird an unterschiedlich substituierten Derivaten geprüft. Es wird ein Mechanismus diskutiert, der die beobachteten Regioselektivitäten und die pH-Abhängigkeit der Stereochemie erklärt.
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    URL: http://dx.doi.org/10.1002/cber.19851180522
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    Synthese mittlerer und großer Ringe, X. (+)- und (-)-[6]Paracyclophan-8-carbonsäure aus (+)- und (-)-3,6-Hexanooxepin-4-carbonsäure (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1996-2010 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Medium and Large Rings, X. (+)- and (-)-[6]Paracyclophane-8-carboxylic Acid from (+)- and (-)-3,6-Hexanooxepin-4-carboxylic AcidThe racemic 3,6-hexanooxepin-4-carboxylic acid ((±)-2d), available in five steps from cyclooctyne and 3-(acetoxymethyl)furan, can be resolved into the enantiomers (+)- and (-)-2d using (+)(R)-1-(1-naphthyl)ethylamine. A stereospecific synthesis of (+)- and (-)-[6]paracyclophane-8-carboxylic acid ((+)- and (-)-4b) is possible from (+)- and (-)-2d as starting materials. Key steps of this synthesis are the transannular addition of bromine to give (-)- and (+)-3a and a subsequent McMurry reaction. The problems involved in the interpretation of the CD-spectra of the oxepin ester (+)-2e and of (+)-4b are discussed in detail.
    Notes: Die aus Cyclooctin und 3-(Acetoxymethyl)furan in fünf Stufen erhältliche racemische 3,6-Hexanooxepin-4-carbonsäure ((±)-2d) kann mit (+)(R)-1-(1-Naphthyl)ethylamin in die Enantiomeren (+)- und (-)-2d gespalten werden. Ausgehend von (+)- und (-)-2d ist eine stereospezifische Synthese von (+)- und (-)-[6]Paracyclophan-8-carbonsäure ((+)- und (-)-4b) möglich. Schlüsselschritte sind dabei die transannulare Bromaddition zu (-)- und (+)-3a und eine anschließende McMurry-Reaktion. Die Probleme der Interpretation der CD-Spektren des Oxepinesters (+)-2e und der Phancarbonsäure (+)-4b werden eingehend diskutiert.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19851180523
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    Beiträge zur Chemie des Bors, 152. 1,3,2,4-Diazaphosphaboretidine und 1,3,2,4-Diazasilaboretidine durch intra- und intermolekulare Cyclokondensation (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2030-2043 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 152. 1,3,2,4-Diazaphosphaboretidines and 1,3,2,4-Diazasilaboretidines Prepared via Intra- and Intermolecular Cyclocondensation1,3,2,4-Diazaphospha(sila)boretidines 5 and 9 are accessible via thermal decomposition of compounds of type E(NR′—BR2)2 (8) or from organoboron dihalides or boron trihalides and E(NR′Li)2 [E = Si(CH3)2, CH3(O)P, R(S)P, CH3P]. The formation of 1,3-di-tert-butyl-4-methyl-(or ethyl)-1,3,2,4-diazaphospha(sila)boretidines from the precursor E(NR′—BR2)2 proceeds by an intramolecular cyclocondensation. NMR data reveal less shielded B and P atoms in the new heterocycles as compared with noncyclic compounds; this is attributed to a strained ring system. A tetracoordinated as well as a tricoordinated boron atom is observed in CH3(O)P(NR′BR2)2 compounds resulting from intramolecular BO coordination.
    Notes: 1,3,2,4-Diazaphospha(sila)boretidine 5 und 9 sind über die thermische Zersetzung von Verbindungen des Typs E(NR′-BR2)2 (8) oder durch Umsetzung von Organylbordihalogeniden bzw. Bortrihalogeniden mit N-Lithio-Verbindungen E(NR′Li)2 [E = Si(CH3)2, CH3(O)P, R(S)P, CH3P] zugänglich. Es wird gezeigt, daß die 1,3-Di-tert-butyl-4-methyl-bzw. -4-ethyl-1,3,2,4-diazaphospha(sila)boretidine aus der Vorstufe E(NR′-BR2)2 durch eine intramolekulare Cyclokondensation entstehen. Nach NMR-Daten sind die Bor- und Phosphor-Kerne in den Vierring-Heterocyclen als Folge der Ringspannung schlechter abgeschirmt als in nichtcyclischen Derivaten. Vierfach koordiniertes Bor liegt neben dreifach koordiniertem in den Verbindungen CH3(O)P-(NR′BR2)2 vor. Dies geht auf intramolekulare BO-Koordination zurück.
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    URL: http://dx.doi.org/10.1002/cber.19851180526
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    Synthese von 4-Oxo-4H-benzothiazolo[3,2-a]pyrimidin-1-ium-2-olaten und ihre Cycloadditionen an elektronenarme und elektronenreiche Alkine sowie an o-Chloranil (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2079-2094 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 4-Oxo-4H-benzothiazolo[3,2-a]pyrimidin-1-ium-2-olates and their Cycloaddition Reactions to Electron-poor and Electron-rich Alkynes as well as to o-ChloranilThe synthesis and physical properties of the title compounds 3a - d, prepared from 1 and bis(2,4,6-trichlorophenyl) malonates 2a - d, are described. As cyclic 1,4-dipoles, the betaines 3 combine with dimethyl acetylenedicarboxylate, dibenzoylethyne or bis(diethylamino)ethyne with formation of primary adducts of type 4, which release methyl isocyanate to give pyrido[2,1-b]-benzothiazole derivatives 5a - g, whereas the reaction of 3a with bis(diethylamino)ethyne yields the betaine 7. With unsymmetrically substituted alkynes like methyl propiolate or 1-(diethyl-amino)propyne, 3 reacts with regiospecific formation of 8a - f. On the other hand, the reaction of 3a with o-chloranil proceeds with regiospecific formation of the 1,4-benzodioxin derivative 11. In the case of 8, the observed regiospecificities are in agreement with the results of MNDO calculations and MO-perturbation theory.
    Notes: Die Synthese und physikalischen Eigenschaften der Titelverbindungen 3a - d aus 1 und Malonsäure-bis(2,4,6-trichlorphenylestern) 2a - d werden beschrieben. Als cyclische 1,4-Dipole vereinigen sich die Betaine 3 mit Acetylendicarbonsäure-dimethylester, Dibenzoylethin oder Bis(diethyl-amino)ethin zu Primäraddukten vom Typ 4, die unter Methylisocyanat-Abspaltung Pyrido-[2,1-b]benzothiazol-Derivate 5a - g liefern, während 3a mit Bis(diethylamino)ethin das Betain 7 ergibt. Mit unsymmetrisch substituierten Alkinen, wie Propiolsäure-methylester oder 1-(Diethyl-amino)propin, reagiert 3 regiospezifisch zu 8a - f. Andererseits führt die Umsetzung von 3a mit o-Chloranil regiospezifisch zu dem 1,4-Benzodioxin-Derivat 11. Die bei 8 beobachteten Regiospezifitäten sind mit den Ergebnissen aus MNDO-Rechnungen und der MO-Störungstheorie in Einklang.
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    URL: http://dx.doi.org/10.1002/cber.19851180528
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    Thermolabile Hydrocarbons, XXVII. 2,3-Di-1-adamantyl-2,3-dimethylbutane; Long Bonds and Low Thermal Stability (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 4665-4673 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermolabile Kohlenwasserstoffe, XXVII. 2,3-Di-1-adamantyl-2,3-dimethylbutan; lange Bindungen und geringe thermische StabilitätDie Titelverbindung 2 wurde durch Wurtz-Synthese dargestellt und eine Kristallstrukturanalyse durchgeführt. Die Strukturdaten des sehr stark deformierten Molekülgerüstes - drei benachbarte CqCq-Bindungen sind länger als 164 pm, CqCqCq-Bindungswinkel sind bis 118° aufgeweitet - werden durch Rechnungen mit dem MM 2-Kraftfeld sehr gut wiedergegeben. Nach den Kraftfeldrechnungen ist 2 der am stärksten gespannte, nach kinetischen Messungen der thermisch labilste Vertreter der bereits früher bearbeiteten CqCq-Alkane.
    Notes: The title compound 2 was prepared by a Wurtz procedure. Its highly deformed structure was determined by X-ray analysis and matched with high precision by MM 2 force field calculations. The three neighbouring CqCq bonds are longer than 164 pm and the CqCqCq bond angles are 118°. According to MM 2 calculations and a kinetic investigation 2 is the most strained and least stable member of the CqCq alkane series investigated previously2).
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    Vitamin-Synthese mit Carben-Komplexen, VI. Stereospezifische Darstellung von Pentacarbonyl[(Z)-dimethoxy-vinyl]carben-Komplexen des Chroms und Wolframs (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1126-1132 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vitamin Syntheses via Carbene Complexes, VI. Stereospecific Synthesis of Pentacarbonyl[(Z)-dimethoxyvinyl]carbene Complexes of Chromium and TungstenThe addition of (E,Z)-1-lithio-1,2-dimethoxyethene (1) to hexacarbonylchromium and -tungsten followed by protonation or alkylation, respectively, provides a stereospecific route to pentacabonyl[(Z)-1,2-dimethoxyvinyl]carbene complexes 2-5. Established by X-ray analysis, the carbene ligand of the methoxycarbene chromium complex 3 is nearly coplanar.
    Notes: Die Addition von (E,Z)-1-Lithio-1,2-dimethoxyethen (1) an Hexacarbonylchrom und -wolfram liefert nach Protonierung bzw. Alkylierung stereospezifisch die Pentacarbonyl[(Z)-1,2-dimeth-oxyvinyl]carben-Komplexe 2-5. Nach der Röntgenstrukturanalyse des (Methoxycarben)chrom-Komplexes 3 ist der gesamte Carbenligand annähernd koplanar.
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    Zwei neue Metallcarbonyle: Darstellung und Struktur von RuCo2(CO)11 und Ru2Co2(CO)13 (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1133-1142 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Two New Metal Carbonyls: Preparation and Structure of RuCo2(CO)11 and Ru2Co2(CO)13RuCo2(CO)11 (1) results from the stoichiometric and heterogeneous reaction between KCo(CO)4 and [Ru(CO)3Cl2]2 in water. Its decomposition in hexane at 65°C yields Ru2Co2(CO)13 (2). The crystallographically determined molecular structures of both compounds show that their metal atom cores are located inside approximately regular ligand polyhedra.
    Notes: RuCo2(CO)11 (1) entsteht durch stöchiometrische heterogene Umsetzung von KCo(CO)4 und [Ru(CO)3Cl2]2 in Wasser. Seine Zersetzung bei 65°C in Hexan liefert Ru2Co2(CO)13 (2). Die kristallographisch bestimmten Molekülstrukturen beider Verbindungen lassen erkennen, daß ihre Metallatom-Kerne sich in annähernd regelmäßigen Ligandenpolyedern befinden.
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    Synthese und Struktur eines hochsubstituierten Tetracyclo[3.3.0.02,8.04,6]octans (Nortriasteran) (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1176-1182 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of a Highly Substituted Tetracyclo[3.3.0.02,8.04,6]octane (Nortriasterane)The 4,8-dibromobicyclo[3.3.0]octa-2,6-diene-2,6-dicarbonitrile 2 reacts with sodium methoxide in methanol quantitatively and with complete stereoselectivity to afford the nortriasteranedicarbonitrile 5. This dinitrile crystallizes triclinically in the space group P1 with two enantiomorphous molecules per cell. Some geometric parameters involving the cyclopropane rings and the mechanism of formation of 5 are discussed.
    Notes: Das 4,8-Dibrombicyclo[3.3.0]octa-2,6-dien-2,6-dicarbonitril 2 reagiert mit Natriummethanolat in Methanol quantitativ und vollständig stereoselektiv zum Nortriasterandicarbonitril 5. Dieses kristallisiert triklin in der Raumgruppe P1 mit zwei enantiomorphen Molekülen in der Elementarzelle. Einige geometrische Parameter der Cyclopropanringe und der Bildungsmechanismus von 5 werden diskutiert.
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    Synthese, Struktur und Umlagerung von Chlorbis(2,4,6-tri-tert-butylphenyl)gallan (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2255-2257 
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    ISSN: 0009-2940
    Keywords: Gallane, chlorobis(supermesityl) ; Rearrangement ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis, Structure, and Rearrangement of Chlorobis(2,4,6-tri-tert-butylphenyl)gallaneThe title compound 1 is easily obtained from GaCl3 and 2 equvialents of supermesityllithium. According to an X-ray structure analysis one of the supermesityl rings shows a large deviation from planarity. Heating of 1 in vacuo gives mainly two products: an isomer of 1 in which one of the supermesityl groups is bound to Ga by one of its tert-butyl groups (2) and a benzo[b]gallolane (3) formed by elimination of HCl, X-ray structure analyses and full NMR (1H, 13C) data are provided for 1 and 2, MS and characteristic NMR (1H, 13C) data for 3.
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    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993) 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/cber.19931260101
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    Darstellung und Eigenschaften von und Reaktionen mit metallhaltigen Heterocyclen, LXXX. Insertions- und Additions-Reaktionen an Diphosphamanganacyclopropanen mit aktivierten Alkinen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 23-29 
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    ISSN: 0009-2940
    Keywords: Diphosphamanganacyclopropanes ; Alkyne insertion ; Alkyne addition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal-;Containing Heterocycles: Preparation, Properties, Reactions, LXXX.  -  Insertion and Addition Reactions on Diphosphamanganacyclopropanes with Activated AlkynesThe thermally and kinetically stable diphosphamanganabicyclooctadienones 3a  -  e [R2 = tBu: R1 = iPr (a), nPr (b), Ph (c); R2 = Cy: R1 = nPr (d), Ph (e)] are obtained by the reaction of the alkyne (CCO2Me)2 with the diphosphamanganacyclopropanes (OC)4Mn-PR12=PR2 (2a  -  e). Depending on steric factors the formation of 3a  -  e occurs in two different ways. In a first step the alkyne is inserted into the P  -  P bond of 2a  -  e to give the kinetically labile five-membered rings 1a  -  e. Subsequently another alkyne is added to the PR2 and a CO group of 1a  -  e to give 3a  -  e. In an alternative way the alkyne is added first to the PR2 and a CO group of 2a with formation of the diphosphamanganabicyclohexenone 4a. Insertion of a second alkyne into the P  -  P bond of 4a affords the bicyclooctadienone 3a. Compound 2a, 3c, and 4a have been characterized by X-ray structural analyses.
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    Mehrfachbindungen zwischen Hauptgruppenelementen und Übergangsmetallen, CXIV. Organorhenium(VII)-oxide (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 45-50 
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    ISSN: 0009-2940
    Keywords: Rhenium compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multiple Bonds between Main Group Elements and Transition Metals, CXIV.  -  Organorhenium(VII) OxidesAlkylrhenium(VII) oxides of formulae RReO3 and RReO3 · L (L = quinuclidine) result from dirhenium heptaoxide and dialkylzinc compounds at low temperatures in THF solution. Unbranched, noncyclic organorhenium oxides prove to be less thermolabile than branched-chain derivatives, with the thermal stability decreasing with increasing chain length. Complexes with branched carbon chains normally can be isolated as 1:1 adducts of a nitrogen base, e.g. quinuclidine. A first chiral alkylmetal oxide and base-stabilized cyclopropyltrioxorhenium(VII) are also described.
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    Notizen / Notes [Li2(THF)4DAD] und [DAD  -  H][ZrCl5(THF)]: Neue Strukturvarianten phenylsubstituierter 1,4-Diaza-1,3-dien-Liganden (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 57-61 
    Details
    ISSN: 0009-2940
    Keywords: Lithium compounds ; Enediamide structure ; 1,4-Diaza-1,3-diene, protonated ; Hydrogen bond ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [Li2(THF)4DAD] and [DAD  -  H][ZrCl5(THF)]: New Types of Phenyl-;Substituted 1,4-Diaza-1,3-diene LigandsTwo extreme situations in 1,4-diaza-1,3-diene (DAD) chemistry are described. Reaction of phenyl-substituted DAD 1a  -  c with lithium in the molecular ratio of 1:2 affords in high yield the extremely air-sensitive complexes [Li2(THF)4DAD] (2a  -  c). The structure of 2b has been determined by X-ray diffraction. Each of the Li+ ions is coordinated by the two terminal N atoms of the s-cis-configurated DAD dianion and by two molecules of THF. Protonation of ZrCl4 · DAD (3a) by HCl in THF gives the ionic complex [ZrCl5(THF)][DAD  -  H] (4), which contains a protonated [DAD  -  H]+ cation. The structure of the sterically crowded N = C  -  C = N skeleton of the [DAD  -  H]+ cation is not influenced by the positive charge and adopts the unusual Z-gauche-Z conformation.
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    Reaktive E = C(p-p)π-Systeme, XXXIII. Side-on-Koordination des Phosphaalkins P ≡ C  -  N(iPr)2 im 16e-Nickel(0)-Komplex Ni(CO)PCy3[PCN(iPr)2] (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 63-65 
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    ISSN: 0009-2940
    Keywords: Phosphaalkyne, amino- ; Nickel carbonyl phosphane complex ; π Coordination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactive E = C(p-p)π Systems, XXXIII.  -  Side-on Coordination of the Phosphaalkyne P ≡ C  -  N(iPr)2 in the 16e Nickel(0) Complex Ni(CO)PCy3[PCN(iPr)2]The reaction of (diisopropylamino)phosphaethyne P ≡ C  -  N(iPr)2 with the nickel complex [Ni(CO)3PCy3] - in contrast to the analogous reactions with Ni(CO)4 or Ni(CO)3PR3 (R = Me, Ph) - leads to the novel 16e nickel(0) system [Ni{η2-P ≡ C  -  N(iPr2)}(CO)PCy3] with a planar geometry of all skeleton atoms besides the methyl and cyclohexyl groups. Side-on coordination of the P ≡ C triple bond results in an increase of the PC distance to 1.665 Ȧ typical for phosphaalkenes.
    Additional Material: 1 Ill.
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    Zur Tautomerie von 5,5-Diphenyldihydro-4H-1,2,3-triazol-4-on und 5-Amino-4,4-diphenyl-4H-1,2,3-triazolen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 103-108 
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    ISSN: 0009-2940
    Keywords: 1,2,3-Triazol-4-ones, 3,5-dihydro-4H- ; 1,2,3-Triazoles, 5-amino-4H- ; Tautomerism ; 15N-NMR Spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tautomerism of 5,5-Diphenyldihydro-4H-1,2,3-triazol-4-one and 5-Amino-4,4-diphenyl-4H-1,2,3-triazolesMethylation of the 5-amino-4H-1,2,3-triazole 5 affords the N-methyl- (12) and the N,N-dimethylaminotriazole 13. X-ray diffraction analyses show that the tautomer 5b exists in the crystal and that 5b and 13 possess similar structures and atomic distances. Both compounds exhibit restricted rotation of the amino groups in solution. The comparison of UV, carbon-13 and nitrogen-15 spectra of the tautomeric triazoles 2 and 5 with those of the N-methyl compounds 3 and 13 demonstrates that the tautomers 2a and 5b are strongly favoured also in solution.
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    3a,6-Dihydro-3H-imidazo[1,2-d]tetrazole aus 1- und 4-Phenacyl-1H-tetrazolium-Salzen und Ammoniak (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 129-132 
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    ISSN: 0009-2940
    Keywords: 3H-Imidazo[1,2-d]tetrazoles, 3a,6-dihydro- ; Tetrazolium salts, 1,5-dialkyl(aryl)-4-phenacyl- ; reaction with ammonia ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3a,6-Dihydro-3H-imidazo[1,2-d]tetrazoles from 1- and 4-Phenacyl-1H-tetrazolium Salts and AmmoniaTreatment of the tetrazolium salts 1 with aqueous ammonia affords the novel ring system 2 (in certain cases along with the ylides 3). The structure of 2 has been confirmed by an X-ray analysis of 2a.
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    URL: http://dx.doi.org/10.1002/cber.19931260120
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    Crystal Structure of the Explosive Parent Benzyne Precursor: 2-Diazoniobenzenecarboxylate Hydrate (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 243-249 
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    ISSN: 0009-2940
    Keywords: Benzyne precursor ; Neighboring group interactions ; Incipient nucleophilic attack ; 2-Diazoniobenzenecarboxylate ; Calculations, ab initio, MO ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of the highly unstable benzyne precursor 2-diazoniobenzenecarboxylate (3) has been determined by single-crystal X-ray diffraction. The structure is discussed in comparison to ab initio results for several conformers of 3, related aromatic diazonium ions, and phenyl cation and also to crystal structures of simple diazonium ion salts and of benzoates. Structural features and characteristic distortions are related to the electron density distributions and to intra- and intermolecular interactions between the neighboring functional groups.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19931260133
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    Darstellung und Charakterisierung von Anthrylenmagnesium-Innerkomplexen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 225-237 
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    ISSN: 0009-2940
    Keywords: Anthracene derivatives ; Magnesium anthracene inner complexes ; 13C CP/MAS NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation and Characterization of Inner Complexes of AnthrylenemagnesiumAnthracene derivatives containing ether or amino groups in 9- or 9,10-position (1 - 10) react with magnesium to form new magnesium anthracene inner complexes (11 - 20). These complexes as well as their organic starting materials have been extensively characterized by spectroscopy and chemical means. It was found that solvent ligands which are present in all magnesium anthracene complexes known to date can be partially or totally replaced by inner complexation. For some of the new magnesium anthracene inner complexes the complex formation rates have been determined.
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    URL: http://dx.doi.org/10.1002/cber.19931260131
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    Reversibility of the [2 + 2] Cycloaddition of Isocyanates to Glycals (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 265-267 
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    ISSN: 0009-2940
    Keywords: [2 + 2] Cycloaddition, reversible ; Glycals ; Isocyanates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [2 + 2] Cycloadducts obtained by the addition of tosyl isocyanate to glycals (10 - 13) undergo retro-addition upon heating or even at room temperature. The rate of retro-addition increases with rising temperature and polarity of the solvent.
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    URL: http://dx.doi.org/10.1002/cber.19931260136
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    Synthesis and Aggregation Properties in Solution of a New Octasubstituted Copper Phthalocyanine: {2,3,9,10,16,17,23,24-Octakis-[(dioctylaminocarbonyl)methoxy]phthalocyaninato}copper(II) (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 269-271 
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    ISSN: 0009-2940
    Keywords: Phthalocyanine, soluble ; Cation-induced phthalocyanine aggregates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the octasubstituted phthalocyanine 1, highly soluble in organic solvents, is described. Its aggregation properties in different solvents and in the presence of alkaline, alkaline earth, and ammonium salts are studied.
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    Organometall-Oxide  -  Höhervalente Derivate der d-Metall-Säuren, 6. Tris(3,5-dimethyl-1-pyrazolyl)boranato-substituierte Alkyl(dioxo)1-, Methylenphosphoranyl(dioxo)1- und s̰1-Allyl(dioxo)1-Komplexe des Molybdäns und Wolframs (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 289-296 
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    ISSN: 0009-2940
    Keywords: Oxo complexes, organometallic ; Borato, hydrotris(3,5-dimethyl-1-pyrazolyl)1-, complexes ; Molybdenum complexes ; Tungsten complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organometallic Oxo Complexes  -  Highervalent Derivatives of the d-Metal Acids, 6.  -  Hydrotris(3,5-dimethyl-1-pyrazolyl)borato-Substituted Alkyl(dioxo)1-, Methylenephosphoranyl(dioxo)1-, and s̰1-Allyl(dioxo) Complexes of Molybdenum and TungstenTp*MoO2Cl (1) and Tp*WO2Cl (2) [Tp* = κ31-HB(3,5-Me2pz)3] react with trimethyl aluminium to form the corresponding dioxo(methyl) complexes Tp*MO2(CH3), M=Mo (3), W (4). An X-ray crystal structure analysis of 3 is performed. The less oxidizing tungsten complex 2 is alkylated by Grignard reagents to yield alkyl complexes of the type Tp*WO2R 5-7 [R=CH2SiMe3, CH2tBu and CH2C(Me)Ph2] and the s̰1-2-methallyl complex Tp*WO2(CH2CMe=CH2) 8. Reactions of 2 with methylenephorphoranes R3P=CH2 (R=iPr, Ph) give transylidation products Tp*WO2(CHPiPr3) (9) and Tp*WO2(CH-PPh3) (10). Hydrolysis of 10 leads to a trioxotungstate [Tp*WO3]- (11), stabilized by a hydroxyphosphonium cation.
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    URL: http://dx.doi.org/10.1002/cber.19931260204
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    all-Homocalixarene: Carbocyclische Wirtverbindungen mit intra- und extraannularen Ligandarmen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2483-2491 
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    ISSN: 0009-2940
    Keywords: Carbocycles ; Homocalixarenes ; Calixarenes, Homo- ; Large rings ; Macrocycles ; [2n]Metacyclophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: all-Homocalixarenes: Carbocyclic Host Compounds with Intra- and Extraannular Ligand ArmsMethoxy-substituted [2n]metacyclophanes 1-10, obtained by Müller-Röscheisen cyclization, are converted into all-homocalixarenes 11-20 with free phenolic hydroxy functions. The well-soluble cyclic pentamer 11 and octamer 14 with endo-acidic host properties are investigated with regard to guest binding. They exhibit selectivity towards alkaline earth metal ions (Ba2+) in liquid/liquid extraction studies. Some of the macrocyclic oligophenols are transformed into homocalixarenes 21-25 with intra- or extraannular oxapropionate groups. The diester 22 and the tetraester 23 are converted into carbocycles 26 and 27 with two and four free oxapropionic acid groups. Complexation properties of the oligoesters in extraction studies and log K values in water are reported. X-ray structural analyses were performed of the [6]-, [8]- and [4]- homocalixarenes 9 and 21, 14 and 23; the inclusion of solvent molecules is proven.
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    Preparation and Conformational Studies of Ethylene-Bridged Calixarene-Analogous Macrocyclic Metacyclophanes (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2501-2504 
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    ISSN: 0009-2940
    Keywords: [(2.1)n]Metacyclophanes, hydroxy- ; Calixarenes ; Trans-tert-butylation ; Conformation ; Hydrogen bonding, intramolecular ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The novel macrocyclic compounds hexahydroxy[2.1.2.1.2.1]- (7b) and octahydroxy[2.1.2.1.2.1.2.1]metacyclophane (7c) have been prepared from anisole in six steps by using the tert-butyl function as a positional protective group on the aromatic ring. Base-catalyzed condensation of 1,2-bis(5-tert-butyl-2-hydroxy-phenyl)ethane (5) with formaldehyde in refluxing xylene does not afford the dimeric product, tetrahydroxy[2.1.2.1]metacyclophane 6a, but furnishes the larger macrocycles 6b and 6c in 70-90% yield. AlCl3/MeNO2-catalyzed trans-tert-butylation of 6b and 6c in toluene gives the desired metacyclophanes 7b and 7c in 60 and 80% yields, respectively, along with tert-butyltoluene 8b. The conformations of the systems such as trimer 6b and tetramers 6c, 7c have been evaluated from their dynamic 1H-NMR spectra. The tetramer 6c is fixed to form a “pleated-loop” conformation like the calix[8]arenes due to the much more stronger intramolecular hydrogen bonding among the hydroxyl groups than in the trimer 6b.
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    Stereoselectivity of the Thermally Initiated Free-Radical Chain Addition of Cyclohexane to 1-Alkynes (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2493-2499 
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    ISSN: 0009-2940
    Keywords: Radicals ; Addition ; Stereoselectivity ; Alkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkanes can be added to alkynes in a thermally initiated free-radical chain reaction (“ane reaction”). The addition of cyclohexane to 1-alkynes 1a-1 yields a mixture of (Z)- and (E)-2-cyclohexyl-1-alkenes 3a-1. An essential step in this reaction is the addition of cyclohexyl radicals to the alkynes to give 2-cyclohexyl-1-alkenyl radicals 2a-1 which abstract hydrogen from cyclohexane to yield the products 3a-1. The stereoselectivity of the addition has been measured in the temperature range of 160-260°C. It strongly depends on the substituent X of the radical center and varies over a range of almost four orders of magnitude from [(Z)-3a]:[(E)-3a] = 33 (X = OMe) at 160°C to [(Z)-31]:[(E)-31] = 0.012 (X = tBu) at 260°C. The stereoselectivity is further influenced by the temperature and in most cases by the concentration of the hydrogen donor cyclohexane. The reaction is discussed in terms of the stereoselectivity of the addition of cyclohexyl radicals to the alkyne, of the structure of the 1-alkenyl radical (σ and π radical, respectively), the rate of inversion in the case of σ alkenyl radicals, and the relative rates of syn and anti hydrogen transfer.
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    Medium-Sized Cyclophanes, 29. Synthesis and Desulfurization of 2,11-Dithia[3]metacyclo- and 2,11-Dithia[3]paracyclo[3](4,9)pyrenophanes (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2505-2511 
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    ISSN: 0009-2940
    Keywords: Cyclophanes ; Benzenopyrenophane, 4,9-bridged ; Sulfones, pyrolysis of ; Photodesulfurization ; [2]Naphthaleno[2]paracyclophane, 1,5-bridged ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,11-Dithia[3]metacyclo- (14b) and 2,11-dithia[3]paracyclo[3]-(4,9)pyrenophane (14c) were obtained by the coupling reactions of 4,9-bis(chloromethyl)pyrene (12) with the corresponding bis(mercaptomethyl)benzenes (13b, c). Attempted pyrolysis of the disulfones 18b, 18c to afford [2]metacyclo- (19b) and [2]paracyclo[2](4,9)pyrenophane (19c) failed. Only the ring cleavage products 16 and 20 were obtained. The sulfur dioxide extrusion by vapor-phase pyrolysis of the corresponding disulfone 18 to the highly strained 19 clearly demonstrates the limits of these preparative ring contraction method. The photolytic desulfurization of 14c afforded the [2](1,5)naphthal-eno[2]paracyclophane analogue 21 instead of [2]paracyclo[1]-(4,9)pyrenophane 21′. The mechanism of the pyrolysis and photolysis reactions is discussed.
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    Flow-Vacuum Pyrolysis of Polycyclic Compounds, 6. Pyrolysis of Dibenzo [CH]8 Hydrocarbons (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2513-2517 
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    ISSN: 0009-2940
    Keywords: Dibenzo [CH]8 hydrocarbons ; Flow-vacuum pyrolysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The flow-vacuum pyrolysis of dibenzo [CH]8 hydrocarbons 2,3,4, and 5 are studied at 1 Torr and in the temperature range between 400 and 650°C. The following new transformations have been observed: 2⇆4, 2→5, 3→5, 3⇆4, 3→2, 5→11, the last three presenting analogies in the [CH]8 and/or benzo [CH]8 series. A reaction mechanism is suggested.
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    On the Reaction of 1-Aza-2-azoniaallene Salts with Carbodiimides (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2519-2524 
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    ISSN: 0009-2940
    Keywords: 1-Aza-2-azoniaallene cations ; Carbodiimides ; 1H-1,2,4-Triazolium salts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Aza-2-azoniaallene cations 3, prepared in situ from geminal (chloroalkyl)azo compounds 2, react with carbodiimides 4 to give 4,5-dihydro-5-imino-1H-1,2,4-triazolium salts 7. An X-ray structural analysis was carried out for 71. According to AM1 calculations the cycloaddition of carbodiimides to 1-aza-2-azoniaallene cations occurs in a nonconcerted manner via cyanamidium cations 5 as intermediates. Hetero-Wagner-Meerwein rearrangements of the primary cycloadducts 6 provide the final products 7.
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    Organophosphorverbindungen, 73. Der Tri-tert-butyl-2-cyclopropen-1-yl-Rest als kinetisch stabilisierende Gruppe für 1-Aza-3-phosphaallene (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2525-2530 
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    ISSN: 0009-2940
    Keywords: Phosphanes, cyclopropenyl- ; Phosphaalkenes, cyclopropenyl ; Shifts, [1,3]-silyl and [1,3]-H ; 1-Aza-3-phosphaallenes ; Cyclopropenyl substituents ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organophosphorus Compounds, 73[1]. - The Tri-tert-butyl-2-cyclopropen-1-yl Substituent as Kinetically Stabilizing Group for 1-Aza-3-phosphaallenes[2]The cyclopropenylphosphane 5 reacts with the isocyanates 6a-g to form the phosphaalkenes 7a-g. An analogous transformation occurs with the same phosphane and the bifunctional isocyanates 8a, b (→ 9a, b). In contrast, the reaction 5 + 6h ends at the stage of the tautomers 11h ⇆ 12h. Methanolysis of 7b and of 11h ⇆ 12h leads to the carbamoyl-cyclopropenylphosphanes 14a and b, respectively. Sodium hydroxide-catalyzed elimination of hexamethyldisiloxane from 7b, g and the tautomer mixture 11h ⇆ 12h yields the target 1-aza-3-phosphaallenes 16a-c.
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    4,5,12,13-Tetrabromo[2.2]paracyclophane - A New Bis(aryne) Equivalent (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2531-2534 
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    ISSN: 0009-2940
    Keywords: [2.2]Paracyclophanes ; 1,2-Dibromoarenes ; anti-[2.2]Paracyclophanes ; Aryne generation ; Diels-Alder reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 2 with nBuLi at -78°C generates aryne intermediates within the aromatic rings of [2.2]paracyclophane which are trapped in Diels-Alder reactions with dienes like furan, 1,9-diphenylisobenzofuran, or cyclopentadiene. Reductive deoxygenation with low-valent titanium reagents or TMSI converts the adducts of furan and isobenzofuran into anti-[2.2]paracyclophanes 4 and 5, respectively. The reaction of two aryne intermediates with [2.2](2,5)furanophane (7) yields 8 with three [2.2]paracyclophane units arranged in a stair-like fashion; yet, in this compound the highly shielded oxygen atoms cannot be removed anymore by reduction.
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    Coordinated 1-Aza-1,3-butadienes: Stable Intermediates in the Formation of Pyridines from [(β-Aminoethenyl)carbene]chromium Complexes (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2535-2541 
    Details
    ISSN: 0009-2940
    Keywords: Chromium, (β-aminoethenyl)carbene complexes ; 1-Aza-1,3-butadienes, coordinated ; Pyridines, cycloaddition with alkynes ; Chelated chromium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [(β-Aminoethenyl)carbene]chromium complexes 3a-c rearrange to coordinated 1-aza-1,3-butadienes 6a-c, which undergo cycloadditions with alkynes 7a, c to pyridines 9a, 10a-c.
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    URL: http://dx.doi.org/10.1002/cber.19931261131
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    A Soluble Benzodifluoranthene Derivative by Dehydration of an Oxygen-Bridged Precursor (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2543-2546 
    Details
    ISSN: 0009-2940
    Keywords: Multicyclic aromatic hydrocarbons, dehydration to ; Multicyclic aromatic hydrocarbons, solubility of ; Benzodifluoranthene derivative ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and characterization of the alkyl chain-substituted benzodifluoranthene 6 are described. The final synthetic step involves an acid-promoted dehydration whose conversion is determined to be quantitative. The solubilities of compounds 4e, 5, and 6 are qualitatively correlated with structural features. The molecular structure of 6 in the crystal is elucidated by an X-ray structure analysis.
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    URL: http://dx.doi.org/10.1002/cber.19931261132
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    Synthese mittlerer und großer Ringe, XXXIV. Stereoselektive Synthese überbrückter und verzweigter Methyl-desoxyfuranoside aus 3,6-Hexanooxepin-4,5-dicarbonsäure-dimethylester (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2547-2551 
    Details
    ISSN: 0009-2940
    Keywords: Furanosides, methyl ; Photochemistry ; Stereoselective reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses of Medium and Large Rings, XXXIV[1,2]. - Stereoselective Synthesis of Bridged and Branched Methyl Deoxyfuranosides from Dimethyl 3,6-Hexanooxepine-4,5-dicarboxylateThe stereoselective synthesis of the bridged methyl furanosides 4-8 with four, five, and six stereogenic centers is described. The reaction sequence starts with the addition of methanol to the oxepine 1. The photochemical electrocyclic ring closure of 2 gives the cyclobutene 3. Ruthenium tetraoxide oxidation of 3 leads to the title compound 4 that is further converted to 5-8 by stereoselective reductions.
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    URL: http://dx.doi.org/10.1002/cber.19931261133
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    Synthese, Struktur und Reaktivität von Diphosphiranen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 645-648 
    Details
    ISSN: 0009-2940
    Keywords: Diphosphiranes, molecular structure of ; 1,2-Diphospha-2-propene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis, Structure, and Reactivity of DiphosphiranesThe 1,1-diamino-1,2-diphospha-2-propen (2,6-Me2C5H8N)2P - P=C(SiMe3)2 (3) is obtained by treatment of bis(2,6-dimethyl-piperidino)(trimethylsilyl)phosphane (1) with [bis(trimethylsilyl)methylene]chlorophosphane (2). Compound 3 readily undergoes thermally isomerization to the diphosphirane 2,6- Nucleophilic substitution of the P1-chloro function of 1-chloro-2-(diisopropylamino)1-3,3-bis(trimethylsilyl)diphosphirane (6) leads to alkyl, amino, phosphanyl, and arsanyl derivatives 7a - d. The corresponding hydrogen derivative 7e is formed by reduction of 6 with tri-n1-butylstannane. The molecular structure of 7c as well as the NMR data of the diphosphiranes are discussed.
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    URL: http://dx.doi.org/10.1002/cber.19931260314
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    Übergangsmetall-Stannyl-Komplexe, 7. Darstellung von Carben-Komplexen (π1-Aromat)(CO)2CrCR2 durch Umsetzung der anionischen Stannyl-Komplexe [(π1-Aromat)(CO)2CrSnPh3]- mit R2CX2 oder [R2CX]Y (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 657-664 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Stannyl complexes ; Chromium complexes ; Anionic complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition Metal Stannyl Complexes, 7[1]. - Preparation of Carbene Complexes (π1-Arene)(CO)2CrCR2 by the Reaction of the Anionic Stannyl Complexes [(π1-Arene)(CO)2CrSnPh3]- with R2CX2 or [R2CX]YCarbene complexes (π1-arene)(CO)2Cr=CR2 are formed in substitution/elimination reactions from the anionic stannyl complexes K[(π1-arene)(CO)2CrSnPh3] [π1-arene=C6H6 (1a), 1,3,5-Me3C6H3 (1b), 1,2,4,5-Me4C6H2 (1c)] C6Me6 (1d) and organic dihalides R2CX2 containing activated C - X bonds or ionic halides [R2CX]Y. Bis(stannyl) complexes (π1-arene)(CO)2Cr(SnPh3)2 (3) and hydrido(stannyl)complexes (π1-arene)(CO)2Cr(H)SnPh3 are formed as byproducts due to the reaction of the eliminated Ph3SnCl with the anionic starting complexes or electron transfer reactions, respectively. The portion and ratio of the byproducts is largely influenced by the steric properties of both the (π1-arene)(CO)2Cr fragment and the organic halide. Pyridinylidene complexes 2) are only obtained from 2-chloro-N1-methylpyridinium tetrafluoroborat with 1a - c, but not with 1d. With the sterically less demanding halides [R2N=C(H)Cl]Cl [NR2=NMe2, (n=3, 4)] or 3,3-dichloro-1,2-diphenylcyclopropene the carbene complexes (π1-arene)(CO)2Cr=C(H)NR2 or are obtained with all employed π1-arene ligands.
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    Vinyliden-Übergangsmetallkomplexe, XXII. Alkin-, Alkinyl(hydrido)1-, Vinyliden-und Vinylvinyliden-Komplexe des Rhodiums aus OH-, NH2- und Cl-funktionalisierten Alkinen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 669-678 
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    ISSN: 0009-2940
    Keywords: Vinylidenerhodium complexes, γ1-functionalized, generation from alkynols and their derivatives ; (Vinylvinylidene)1- and allenylidenerhodium complexes, formation by HX elimination ; Alkynyl(hydrido)1- rhodium(III) complexes, preparation from alkyne or vinylidene precursors ; Rhodium complexes, cyclopentadienyl, with vinylvinylidene ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vinylidene Transition Metal Complexes, XXII[1]. - Alkyne, Alkynyl(hydrido)1-, Vinylidene-, and Vinylvinylidene Complexes of Rhodium from OH-, NH2-, and Cl-Functionalized Alkynes
    Notes: The reaction of [RhCl(PiPr3)2]n with γ1-functionalized 1-alkynes HC≡C-CRR′X (X=OH, OMe, Cl, NH2) at room temperature leads to the formation of either alkyne-, alkynyl(hydrido)1-, or vinylidenerhodium complexes. The alkyne and alkynyl-(hydrido) derivatives rearrange thermally or in the presence of deactivated Al2O3 to the isomeric vinylidenerhodium compounds in almost quantitative yield. On treatment of the γ1-functionalized vinylidenerhodium complexes trans-[RhCl(=C=CH-CRR′X)(PiPr3)2] with Al2O3 or traces of acids, elimination of HX occurs and (for R=H, CH3; R′=CH3; X=OH, Cl, NH2) the (vinylvinylidene)rhodium compounds trans-[RhCl(=C=CH-CR=CH2)(PiPr3)2] are formed. In contrast, the reaction of trans-[RhCl(=C=CHCPh2OH)(PiPr3)2] with either Al2O3 or acid gives the allenylidene complex trans-[RhCl(=C=C=CPh2)(PiPr3)2]. The 1-hexyne derivatives HC≡C[CH2]3CH2X (X=OH, Cl) react with [RhCl(PiPr3)2]n to give alkyne-, alkynyl(hydrido)1-, and vinylidenerhodium compounds; attempts to form the cyclic vinylidene complex trans- by HX elimination from trans-[RhCl(=C=C=CH[CH2]3CH2X)(PiPr3)2] (X=OH, Cl) failed. The half-sandwich-type (vinylvinylidene)rhodium compounds [C5H5Rh(=C=CH-CR=CH2)(PiPr3)] (R=H, Me) are obtained from [RhH(C≡C-CR=CH2)Cl(py)(PiPr3)2] and NaC5H5.
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    URL: http://dx.doi.org/10.1002/cber.19931260318
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    (Bicyclo[3.2.0]hepta-1,3-dienyl)cobalt(I) Complexes (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 713-724 
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    ISSN: 0009-2940
    Keywords: Bicyclo[3.2.0]hepta-1,3-dienyl complexes ; Calculations, semiempirical ; Alkyne trimerization ; Cobalt complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three isomeric bicyclo[3.2.0]heptadienes 1 - 3 are compared by semiempirical calculations. Experimental attempts directed to the synthesis of derivatives of 1 are described. The synthesis, properties and some reactions of (η51-bicyclo[3.2.0]hepta-1,3-dienyl)(η41-cycloocta-1,5-diene)cobalt(I) (22), including an X-ray crystal structure determination of the reaction product with diphenylethyne, the tetraphenylcyclobutadiene complex 30, are presented.
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    Synthese und Struktur von Phosphiren-Iminen und Iminophosphaspiro[2.2]pentanen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 649-655 
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    ISSN: 0009-2940
    Keywords: λ51-Phosphirenes, imino- ; λ51-Phosphaspiro[2.2]pentanes, imino ; Imines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Structure of Phosphirene Imines and Iminophosphaspiro[2.2]pentanesThe reaction of the iminophosphanes R1P=NR2=[1, R2=2,4,6-tBu3C6H2;R1=Me (a) Et (b), PhCH=CH (c), Cl (d); R2=tBu, R1=Et3C (e)] with the alkynes R3C ≡ CR4 [2, R3=R4=Ph (a), CO2Me (b)] affords the corresponding phosphirene imines 3a - g. A [2 + 1] cycloadduct 3h is also formed in the reaction of the alkyne 2c (R3=H, R4=Ph) with 1d, while in the case of 1b the 1,2-addition product 4 is obtained. As demonstrated by the [2 + 1] cycloaddition reaction of the P1-alkylated iminophosphanes 1a, b with methylene-cyclopropanes 5a, b, the formation of the iminophosphaspiro[2.2]pentanes 6a, b is observed. The structures of the P/C heterocycles 3a, b and 6b have been determined by NMR spectroscopy and X-ray analysis.
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    URL: http://dx.doi.org/10.1002/cber.19931260315
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    Schwefel(IV)1-Verbindungen als Liganden, 19. Kationische Ruthenium-Sulfen-Komplexe: Synthese und Reaktionen. Kristallstrukturanalyse von [Cp*(Me3P)2Ru(CH2=SO2)]PF6 (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 679-684 
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    ISSN: 0009-2940
    Keywords: Ruthenium complexes ; Sulfur dioxide complexes ; Sulfene complexes ; Nucleophilic addition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sulfur(IV) Compounds as Ligands, 19[1]. - Cationic Ruthenium-Sulfene Complexes: Synthesis and Reactions. Crystal Structure Analysis of [Cp*(Me3P)2Ru(CH2=SO2)]PF6Methylene addition to coordinated sulfur dioxide yields the novel η2(C, S) sulfene complexes [Cp(dppm)Ru(CHR=SO2)]PF6 (R=H:3, Me: 4) and [Cp*(Me3P)2Ru(CH2=SO2)]PF6 (5). An X-ray structure determination of 5 reveals a relatively short C - S bond (167.5 pm). The sulfene complexes are powerful carbon electrophiles as shown by the rapid addition of halides, pseudohalides, amines, including „nonnucleophiles“ such as ethyldiisopropylamine and DBU, and phosphanes to 3. The regioselectivity of the reaction of 3 with enamines is opposite to that of free sulfene, i.e. coordination of the sulfene to ruthenium effects umpolung.
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    Monofunktionelle tetraedrische Zink-Komplexe L3ZnX [L3=Tris(pyrazolyl)borat] (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 685-694 
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    ISSN: 0009-2940
    Keywords: Zinc complexes ; Tris(pyrazolyl)borat ligands ; Reactivity ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monofunctional Tetrahedral Zinc Complexes L3ZnX [L3=Tris(pyrazolyl)borate]The pyrazolyl borates K[HBpz3*] (abbreviated KL3, pz*=3-phenyl-, 3-tolyl-, 3-anisyl-3,5-diphenyl pyrazolyl) react with zinc salts ZnX2 (X=Cl, Br, I, NO3) to form the mononuclear neutral tetrahedral zinc complexes L3ZnX (1 - 4). The corresponding alkylzinc complexes L3ZnR (5 - 8; R=Me, Et, tBu, Ph) result either from L3ZnCl and LiR or from ZnEt2 and KL3. These alkylzinc compounds are remarkably stable towards oxidation and hydrolysis. For specific cases the reaction of L3ZnR with carboxylic acids is found to yield the carboxylates L3ZnOCOR (9, 10), and likewise with thioacetic acid to yield the thioacetates L3ZnSCOMe (11). Facile cleavage of L3ZnR with thiols and selenophenol produces the thiolates L3ZnSR (12, 13) and the selenolates L3ZnSePh (14). The complexes L3ZntBu which are the most reactive of the alkylzinc compounds are cleaved by H2O, H2S, NH3 and various OH and NH compounds with formation of the bis(ligand) complexes Zn(L3)2 (15). Crystal structure determinations of one L3ZnX complex each for X=NO3 (4a), CH3 (5a), SCOMe (11a), and SEt (12a) confirm the nature of the compounds and the relation of 4a and 12a to the active centers of zinc-containing enzymes.
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    Nucleophile Singulett-Carbene in der [4 + 1]1-Cycloaddition mit 1,2,4,5-Tetrazinen: Eine neue Isopyrazol-Synthese (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 733-738 
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    ISSN: 0009-2940
    Keywords: Singlet carbenes ; [4 + 1] Cycloadditions ; Isopyrazoles ; Diels-Alder reactions ; [4 + 2] Cycloreversion ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nucleophilic Singlet Carbenes in the [4 + 1] Cycloaddition with 1,2,4,5-Tetrazines: a New Synthesis of IsopyrazolesA series of 3,6-disubstituted 1,2,4,5-tetrazines 6, including C6H5, SCH3, SO2CH3, N(CH3)2, CF3, CO2CH3 groups, has been submitted to [4 + 1] cycloaddition with the nucleophilic singlet carbenes 4, 15, and 20, which are generated from the precursors 1, 11 and 19, resp. In all cases isopyrazoles (4H1-pyrazoles) 9, 10, 18, and 21 are isolated in good yields. They are formed in a two-step reaction sequence with the [4 + 1] cycloadducts of type 8 as intermediates which eliminate nitrogen by subsequent [4 + 2] cycloreversion. The acceptor-substituted isopyrazole 9e is characterized as an electron-deficient diene by some Diels-Alder reactions with inverse electron demand leading to the expected azo-bridged cycloadducts 23, 25, 27, 29, and 31 without acid catalysis or application of higher pressure. With cyclooctyne (32), the [4 + 2] cycloaddition is followed by a [4 + 2] cycloreversion with formation of the cyclopentacyclooctene 34.
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    Metall-π1-Komplexe von Benzolderivaten, XLI. Bis(η61-anilin)chrom: Synthese, Redoxverhalten und Brønsted-Basizität (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 399-404 
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    ISSN: 0009-2940
    Keywords: Chromium complexes ; Aniline as an η61-ligand ; Voltammetry, cyclic ; Nerst-Clark plots ; Acid dissociation constants ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal π Complexes of Benzene Derivatives, XLI[1].  -  Bis(η61-aniline)chromium: Synthesis, Redox Properties and Brønsted BasicityBis(η61-aniline)chromium (6) has been prepared by protodesilylation of its N,N,N′,N′1-tetrakis(trimethylsilyl) derivative 5, which is accessible by metal-atom ligand-vapor cocondensation (cc). Bis(η61-dimethylaniline)chromium (3) is obtained directly from cc. The couples 3+/0 and 6+/0 feature the most negative redox potentials E1/2 ever reported for bis(arene)1-metal complexes. According to EPR spectroscopy, applied to the radical cations 3+· and 6+· the site of oxidation is largely localized on the metal. The pH dependence of E1/2 is cast in Nerst-Clark plots, whose breaks supply the pKs values of the mono-and diprotonated forms of 3 and 6. η61-Coordination to CrI increases the basicity of aniline by three pK units, whereas η61-coordination to Cr1 effects a decrease by more than seven pK units. The first and second dissociation constants of the organometallic bis(ammonium) ions 3(H+)2 and 6(H+)2 differ by 2.7 pK units. This interval reflects the interaction of the two basic centers in 3 and 6 which approaches that of p1-phenylenediamine. Thus, conjugation across the bis(η61-arene)chromium unit is virtually uninhibited.
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    Bis(pentamethylcyclopentadienyl)keton und -thioketon: Kohlenstoff-Verbindungen mit präformierter Diels-Alder-Geometrie (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 415-420 
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    ISSN: 0009-2940
    Keywords: 1,3-Cyclopentadiene-5-carbonyl chloride, 1,2,3,4,5-pentamethyl- ; 1,3-Cyclopentadiene-5-carbothioyl chloride, 1,2,3,4,5-pentamethyl- ; Ketone, bis(1,2,3,4,5-pentamethyl-1,3-cyclopentadien-5-yl) ; Thioketone, bis(1,2,3,4,5-pentamethyl-1,3-cyclopentadien-5-yl) ; Diels-Alder preformation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis(pentamethylcyclopentadienyl) Ketone and Thioketone: Carbon Compounds with Performed Diels-Alder Geometry1,2,3,4,5-Pentamethyl-1,3-cyclopentadien-5-carbonyl chloride (2) is formed in good yields by the reaction of pentamethylcyclopentadienyllithium (1) with phosgene. The corresponding carbothioyl chloride 3 is synthesized by treatment of 1 with thiophosgene. Both acyl chlorides are stable against air and moisture and difficult to attack in SN2-type reactions. Treatment of 2 and 3 with trimethyl(pentamethylcyclopentadienyl)stannane in the presence of boron trifluoride  -  ether leads to bis(1,2,3,4,5-pentamethyl-1,3-cyclopentadien-5-yl) ketone (5) and thioketone (6), respectively. Even at room temperature, 5 and 6 tend to intramolecular [4 + 2] cycloaddition reactions. X-ray crystal structure investigations of 2, 5, and 6 show the steric demand of the pentamethylcyclopentadienyl ligand and explain the untypical chemical behavior of 2 and the easy [2 + 4] cycloaddition reactions of 5 and 6.
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    Multistep Redoxsystems, LX. 1,4,5,8-Tetraoxo-1,4,5,8-tetrahydrothianthrene: Synthesis, Structure, and Spectroelectrochemical Properties (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 465-471 
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    ISSN: 0009-2940
    Keywords: Thianthrene derivatives ; X-ray analysis ; MO calculation ; Cyclovoltammetry ; UV-Vis spectroelectrochemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis, structure, cyclovoltammetric and spectroelectrochemical data of 1,4,5,8-tetraoxo-1,4,5,8-tetrahydrothianthrene (2a) are presented. A relation between the positive partial charge at the sulfur atom and the dihedral angle at the S—S axis is discussed on the basis of semiempirical MO calculations.
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    Neue Beobachtungen zur Stereoselektivität von Monoiodcarben-Additionen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 499-502 
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    ISSN: 0009-2940
    Keywords: Iodocarbene, addition to alkenes ; endo1-Selectivity ; Cyclooctadiene ; Cyclooctatetraene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Observations Concerning the Stereoselectivity of Monoiodocarbene AdditionsContrary to our earlier claim, CHI gives endo/exo isomer mixtures with cyclooctene. However, only endo1-iodo compounds 7, 8, 10-12 are obtained from COD and COT. Tricyclic compound 7 rearranges partially to bicyclic 9, X-ray structure determinations of 7 and 9 were performed.
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    Reaktivität s̰1-bishomoaromatischer Heterocyclen: Elektrocyclische Reaktionen und Cycloadditionen von syn- und anti1-Bishomofuran und -BishomothiophenProfessor William von E. Doering zum 75. Geburtstag gewidmet. (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 485-498 
    Details
    ISSN: 0009-2940
    Keywords: Carbonyl ylides, generation from syn1-bishomofuran ; Thiocarbonyl ylides, generation from syn1-bishomothiophene ; Ylides, carbonyl and thiocarbonyl, 1,3-dipolar cycloaddition, electrocyclization, sigmatropic 1,4-hydrogen shift of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactivity of s̰1-Bishomoaromatic Heterocyles: Electrocyclic Reactions and Cycloadditions of syn- and anti1-Bishomofuran and -BishomothiopheneProfessor William von E. Doering zum 75. Geburtstag gewidmet.The title compounds syn-4a, b and anti-4a, b, synthesized by the CuCl-catalyzed reaction of homofuran 1a or homothiophene 1b with diazomethane, are very different in their thermal stability. syn-4a isomerizes to 2,3-dihydrooxepine (7a) readily at 130°C whereas the rearrangement anti-4a → 7a requires a temperature of about 370°C. A similar difference in thermal reactivity is observed between syn-4b and anti-4b. But syn-4b undergoes in addition to the rearrangement to 2,3-dihydrothiepine (7b) a dimerization (to 12?) on thermolysis in [D6]benzene solution at 140°C, whereas mainly isomerization to 9b, cis-10b, and 11 (product of the elimination of sulfur from cis-10b) occurs on thermolysis in the gas phase. The formation of 7a and 7b, respectively, is explained by the electrocyclic ring opening of syn-4a or syn-4b leading to the carbonyl ylide 5a or the thiocarbonyl ylide 5b followed by a sigmatropic 1,4 hydrogen shift. To rationalize the additional products in the thermolysis of syn-4b an electrocyclic conrotatory ring closure in 5b leading to the highly strained episulfide trans-10b is assumed to complete with the hydrogen shift. Under the reaction conditions trans-10b is unstable and either dimerizes in solution or isomerizes in the gas phase. The formation of 9b in the thermolysis of syn-4b indicates that a two-step pathway may compete with the concerted process. syn-4a, b react with various π acceptor-substituted olefins to form cycloadducts of the general type 6a, b. The cycloaddition occurs stereospecifically cis with respect to the configuration of the starting olefin and non-stereoselectively with respect to the endo/exo ratio. The kinetic analysis of the reaction of syn-4a with fumaronitrile (FN), N1-phenylmaleinimide (NPMI) or dimethyl dicyanofumarate (DCFM) shows unambiguously, that the adducts are formed by a 1,3-dipolar cycloaddition of the intermediate carbonyl ylide 5a rather than a homo-Diels-Alder reaction of syn-4a (in contrast to the cycloaddition of homofuran 1a). A comparison between the enthalpies of reactions syn-4a → 5a (ΔHR ≤ 22.4 kcal/mol) and syn-4d → 5d (ΔHR ≥ 47.5 kcal/mol) shows the carbonyl ylide to be a 1,3-diradical, highly resonance-stabilized by the heteroatom (resonance energy R.E. ≍ -25 kcal/mol).
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19931260228
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    1-Sila-3-alumina-4-aluminatacyclopentan mit Al-Al-Bindung und C2Al2Si-Heterocyclus (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2637-2641 
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    ISSN: 0009-2940
    Keywords: Aluminium-aluminium bond ; C2Al2Si heterocycle ; Aluminium, three- and fourfold coordinated ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Sila-3-alumina-4-aluminatacyclopentane with an Al-Al Bond and a C2Al2Si HeterocycleTetrakis[bis(trimethylsilyl)methyl]dialuminium(4) (1) with an aluminium-aluminium bond reacts in the presence of tetramethylethylenediamine (TMEDA) with the sterically highly shielded bases bis(trimethylsilyl)methyllithium or bis(dimethylphosphanyl)methyllithium to yield under deprotonation of a methyl group a carbanionic species, which is stabilized by an interaction with one of the coordinatively unsaturated Al atoms. The five-membered heterocycle 5 is formed containing two Al, one Si and two C atoms. The Al-Al bond remains uncleaved. Interestingly, 5 crystallizes in different crystals with and without crystal ether, which were both characterized by crystal-structure determinations. The Al-Al bond length in 5 [264.1(2) and 266.5(3) pm, respectively] is only slightly changed in comparison to the neutral starting compound 1 (266.0 pm). Under similar conditions the sterically less demanding ethyllithium leads to a β-elimination and addition of the thereby formed LiH to one of the two Al atoms to give the recently published hydridodialuminate(5) Li(TMEDA)2+ [R2Al-AlHR2]- (2).
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19931261211
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  • 95
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    Homo- und Hetero-Metall-Amide des Tris(tert-butylamino)methylsilans - Polycyclen und Cluster mit Li, Na, Mg, Al und Tl (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2625-2635 
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    ISSN: 0009-2940
    Keywords: Amides, hetero metal ; Polycycles ; Metal clusters of thallium ; Metal nitrogen bonding ; Carbanion, stabilized by metal complexation ; Silane, tris(tert-butylamino) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homo and Hetero Metal Amides of Tris(tert-butylamino)methylsilane - Polycycles and Clusters with Li, Na, Mg, Al and TlThe hydrogen atoms attached to nitrogen in tris(tert-butyl-amino)methylsilane (1) can be substituted by metallic main-group elements in a quite general way. If 1 is treated with trimethylaluminium apart from the monosubstituted product MeSi(tBuNH)2(tBuNAlMe2) (2) the trisamide MeSi(tBuNAlMe2)3 (3) is obtained. In similar ways complete substitution of the amino hydrogen atoms in 1 yields the compounds MeSi[tBuNMgN(SiMe3)2]3 (6), [MeSi(tBuNLi)3]2 (10), and [MeSi(tBuNTl)3]2 (11), the later two being dimeric. If methyl-magnesium iodide is allowed to react with 1 the intermediate MeSi(tBuNMgI)3 (4) in some instances can be isolated as the THF adduct or may react with a further equivalent of the Grignard compound to generate the complex [MgI-(THF)5]+ [MeSi(tBuNMgI)3CH3 · THF]- (5). The aluminium compound 2 has been used to access to heterometallic amides combining aluminium and sodium as in MeSi(tBuNAlMe2)(tBuNNa)(tBuNH) (7) or magnesium and aluminium as in the dimeric compounds [MeSi(tBuNAlMe2)(tBuNH)(tBuNMgI)]2 (8) and [MeSi(tBuNAlMe2)(tBuNH)(tBuNMgMe)]2 (9). X-ray structure analyses reveal 3 (tricyclic SiN3Al3 skeleton with Al - N distances from 2.014 to 2.025 Å), 6 (tricyclic Si-N3Mg3 skeleton), and 7 [bicyclic SiN3AlNa skeleton with Na - N distances of 2.47(1) and 2.52(1) Å] to be monomeric even in the solid state. The compounds 8 and 9 (both pentacyclic with spiro magnesium atoms) form centrosymmetric dimers by Mg - I - Mg and Mg - (CH3) - Mg bridges, respectively. The dimers 10 and 11 are completely different in terms of chemical bonding: while in the lithium compound 10 a centrosymmetric polycycle is formed by principly ionic interactions of the lithium atoms with corresponding nitrogen atoms, the centrosymmetric dimer in 11 is held together by Tl - Tl bonds. The X-ray structure analysis of 5 reveals the anion containing a Mg-coordinated CH3-.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19931261210
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  • 96
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    Tetraindeno-Fused Cyclooctatetraene and Oligomeric Biindenyls by Oxidative Coupling of 2,2′1-Biindenyl (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 969-973 
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    ISSN: 0009-2940
    Keywords: 1,1′1-Bi(2,2′1-biindenylyls) ; Carbanions ; Oxidative coupling ; Cyclooctatetraindenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lithiated biindenyls 2 and 4, prepared by deprotonation of 2,2′1-biindenyl (1) and 10,11-dihydrodiindeno[1,2-b:2′,1′-d]thiophene (3) with n1-butyllithium, are oxidatively coupled to give oligomeric biindenyls (17) as well as tetraindeno-fused eight-membered rings (16, 19, 24).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260418
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  • 97
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    Zinkkomplexe von Aminosäuren und Peptiden, 2[1]. Koordination einfacher Histidin-Derivate an Zink (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2643-2648 
    Details
    ISSN: 0009-2940
    Keywords: Histidine derivatives ; Zinc complexes ; Solution equilibria ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Zinc Complexes of Amino Acids and Peptides, 2[1]. - Coordination of Simple Histidine Derivatives to ZincThe bis(L-histidine)ZnCl2 complex 1 is likely to have tetrahedral ZnN2Cl2 coordination. For the compound (L-histidine)-ZnCl2 · HCl (2) a structure determination has revealed a tetrahedral ZnOCl3 coordination. Of the C-protected histidine derivatives His-OMe and His-NH2 and zinc salts of non-coordinating anions the complexes (His-OMe)2ZnX2 (3) and (His-NH2)2Zn(ClO4)2 (4) were obtained. A structure determination of (His-OMe)2Zn(BPh4)2 · H2O has revealed a ZnN4 coordination with chelating histidine units. Of the N-protected histidine derivative Nα-acetylhistidine the complexes (Ac-His)ZnX · H2O (5, X = ClO4, BF4) have been isolated which are coordination polymers in the solid state. From pH-dependent 13C-NMR studies it is concluced that in solution the imidazole N and carboxyl O are coordinated to zinc in (Ac-His)Zn and (Ac-His)2Zn units. The doubly protected histidine derivative Bz-His-OMe acts as a monodentate ligand forming the tetrahedral complexes (Bz-His-OMe)4Zn(ClO4)2 (6) and [(Bz-His-OMe)2Zn(2,9-dimethyl-o-phenanthroline)](ClO4)2 (7).
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19931261212
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  • 98
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    Synthese und Röntgenstrukturanalyse einer neuartigen gemischtvalenten zwitterionischen Diphosphor-Fluor-Verbindung (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2653-2655 
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    ISSN: 0009-2940
    Keywords: Diphosphorus zwitterion ; Phosphorus, hexacoordinated ; Phosphorus, tetracoordinated ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and X-Ray Crystal Structure Analysis of a Novel Mixed-Valent Zwitterionic Diphosphorus Fluoro CompoundThe cyclic zwitterionic λ6P,λ4P-diphosphorus compound F5P-N(Me)P+ [N(Me)C(=O)]2NMe (3), which contains a biuret system, was synthesized by the reaction of (MeNPF3)2 (1) with MeNCO (2). Compound 3 was characterized by means of 1H-, 13C-, 19F- and 31P-NMR spectroscopy, IR spectroscopy, and mass spectrometry. A single-crystal X-ray structure determination revealed the presence of two independent formula units, in which the -N(Me)PF5 side chains display widely differing conformations.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19931261214
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    Metallorganische Verbindungen der Lanthanoide, 82[1]. (2,5-Di-tert-butylpyrrolyl)-Komplexe von Neodym(III), Samarium(II) und Ytterbium(II): Synthese und Röntgenstrukturanalyse von dimerem Natrium-dichlorobis(2,5-di-tert-butylpyrrolyl)(tetrahydrofuran)neodymat(III) (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2657-2659 
    Details
    ISSN: 0009-2940
    Keywords: Azacyclopentadienyl complexes ; Neodymium compounds ; Samarium compounds ; Ytterbium compounds ; Lanthanoides, organo-, chlorides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organometallic Compounds of the Lanthanoids, 82[1]. - [2,5-Di-tert-butylpyrrolyl) Complexes of Neodymium(III), Samarium(II), and Ytterbium(II): Synthesis and X-Ray Structural Analysis of Dimeric Sodium Dichlorobis(2,5-di-tert-butylpyrrolyl)(tetrahydrofuran)neodymiate(III)NdCl3(THF)1,8 reacts with Na[pyr*
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19931261215
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  • 100
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    Ephedrine-Derived Imidazolidin-2-ones. Broad Utility Chiral Auxiliaries in Asymmetric Synthesis (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2663-2673 
    Details
    ISSN: 0009-2940
    Keywords: Imidazolidin-2-one, (4R,5S)-1,5-dimethyl-5-phenyl- or cyclohexyl- ; (-)-Ephedrine ; Stereoselective aldol ; alkylation, acylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The scope of the readily available (4R,5S)-1,5-dimethyl-4-phenylimidazolidin-2-one (4) and its 4-cyclohexyl analogue 6 as practical, efficient chiral auxiliaries has been demonstrated. The enolate chemistry of their N-acyl derivatives exhibits features which recommend their use in asymmetric synthesis. The stereoselective boron-mediated aldol as well as alkylation and acylation results are presented. The steric control benefit derived by conversion of phenyl to cyclohexyl is highlighted.
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    URL: http://dx.doi.org/10.1002/cber.19931261216
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