Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: NMR Investigations on Dimeric Dialkylthallium Compoounds with (TIX)2 Four-membered Ring StructureNMR investigations on dimeric dialkylthallium amides and on dimethylthallium diphenylphosphide indicate a significant influence of the largeness of the bridging groups on the binding strength in the (TIX)2-four-membered ring structure. Exchange reactions among different dimeric dialkylthallium compounds give evidence of a dimer-monomer equilibrium, which is of fundamental importance for the reactivity and the reaction mechanisms of these compounds.
    Notes: NMR-Untersuchungen an dimeren Dialkylthalliumamiden und am Dimethylthalliumdiphenylphosphid indizieren einen signifikanten Einfluß der Größe der Brückengruppen auf die Bindungsstärke in den (TIX)2-Vierringen. Austauschreaktionen zwischen unterschiedlichen dimeren Dialkylthalliumverbindungen beweisen ein Dimer-Monomer-Gleichgewicht, das von grundsätzlicher Bedeutung für die Reaktivität und die Reaktionsmechanismen dieser Verbindungen ist.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Chemical Properties of 2,3-Dihydro-1,3,2λ5-benzoxazastibolesThe synthesis of the benzoxazastiboles 1-9 starting from o-aminophenols and triarylantimony dibromides (route A) or o-aminoaroxyls and triarylstibines (route B) is described. These heterocycles do not react with bases, however with mineral acids solvolysis is observed. Temperatures above 25°C lead to further reactions, and finally a new nine-membered ring can be isolated. Under oxidative conditions a cleavage of the oxazastiboles takes place, and phenoxazinyl radicals are formed from the fragments. The regiospecifity of this reaction was confirmed by means of e.s.r. spectroscopy.
    Notes: Die Synthese der Benzoxazastibole 1-9 aus o-Aminophenolen und Triarylantimondibromiden (Weg A) oder o-Aminoaroxylen und Triarylstibinen (Weg B) wird beschrieben. Gegenüber basischen Reagentien sind die Heterocyclen stabil, während im sauren Medium Solvolyse erfolgt. Bei Temperaturen oberhalb 25°C findet Weiterreaktion zu neungliedrigen Ringsystemen statt. Unter oxidativen Bedingungen werden die Oxazastibole gespalten, wobei Phenoxazinyl-Radikale entstehen. Die Regiospezifität dieser Reaktion wird durch ESR-Untersuchungen nachgewiesen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 6,13-Dialkyl-1,8-dihydro-1,4,8,11-tetraaza[14]annulene-2,3,9,10- tetracarbonitriles6,13-Dialkyl-1,8-dihydro-1,4,8,11-tetraaza[14]annulene-2,3,9,10- tetracarbonitriles 3, the first nonfused representatives of the tetraaza[14]annulenes, are formed by direct cyclization of diaminomaleonitrile (1) with 2-alkyl-3-ethoxyacroleins (2) in yields of up to 30%. The macroheterocycles react with nickel(II) ions to yield deep red violet N4 chelates 4. The latter are also obtained by metal template reaction of 1 with 2 and nickel(II) acetate.
    Notes: 6,13-Dialkyl-1,8-dihydro-1,4,8,11-tetraaza[14]annulen-2,3,9,10 -tetracarbonitrile 3, die ersten nicht anellierten Vertreter der Tetraaza[14]annulene entstehen durch direkte Cyclisierung von Diaminomaleinsäuredinitril (1) mit 2-Alkyl-3-ethoxyacroleinen (2) in Ausbeuten bis zu 30%. Die Makroheterocyclen reagieren mit Nickel(II)-Ionen zu tiefrotvioletten N4-Chelaten 4, die auch durch Metalltemplat-Reaktion von 1 mit 2 und Nickel(II) -acetat entstehen.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A New, Convenient Synthesis of Highly Acidic TetraarylpropenesFluorene, substituted fluorenes and azafluorenes, respectively, react with acetonitrile in the presence of powdered potassium hydroxide and molecular oxygen to give tetraarylpropenes in good yields.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    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 Indole, VII. Syntheses in the Iboga-Series, III. Ibogamine, Ibogaine, and EpiibogamineStarting from dimethyl malonate, methyl acrylate, o-nitrotoluene, diethyl oxalate, ethyl bromoacetate, and hydroxylamine, both the iboga and epiiboga alkaloids have been synthesised stereoselectively in only fourteen steps by a novel indole synthesis. This synthesis proves the configuration.
    Notes: Ausgehend von Malon- und Acrylester, o-Nitrotoluol, Oxalester, Bromessigester und Hydroxylamin werden in 14 Stufen jeweils stereoselektiv sowohl die Iboga- als auch die Epiiboga-Alkaloide nach einer neuen Indolsynthese erhalten. Diese Synthesen sind konfigurationsbeweisend.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Borabenzene Derivatives, X. Formation of Borinato Ligands from a 1-Bora-2,5-cyclohexadiene Derivative in Complexes of Manganese, Rhenium, and IronBorinato complexes LMn(CO)3, LRe(CO)3, and FeL2 (3-5), where L is the 4-methyl-1-phenylborinato ligand, are obtained by thermal reaction of 4,4-dimethyl-1-pheny-1-bora-2,5-cyclohexadiene (1) with Mn2 (CO)10 and Re2(CO)10 and by thermolysis of tricarbonyl(4,4-dimethyl-1-phenyl-1-bora-2,5-cyclohexadiene)iron (2).
    Notes: Borinato-Komplexe LMn(CO)3, LRe(CO)3 und FeL2 (3-5), wo L der 4-Methyl-1-phenylborinato-Ligand ist, werden durch thermische Reaktion von 4,4-Dimethyl-1-phenyl-1 bora-2,5-cyclohexadien (1) mit Mn2(CO)10 und Re2(CO)10 und durch Thermolyse von Tricarbonyl-(4,4-dimethyl-1-phenyl-1-bora-2,5-cyclohexadien)eisen (2) erhalten.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclopropylmethyl-, Cyclopropylethyl-, and Cyclopropylisopropylacetylene - Synthesis and Metalation ReactionsMethyl-(1b), ethyl-(1c) substituted cyclopropylacetylenes are prepared in 30-g-scale and metalated with n-buyllithium. With usual trapping reagents a number of new compounds (11 - 38) is produced and the following is shown: 1b is metalated only at the methyl group, 1c both at the methylene group and the cyclopropane ring, 1d exclusively at the cyclopropane ring. Dimetalations are not detectable even under drastic reaction conditions.
    Notes: Methyl-(1b), äthyl-(1c)substituiertes Cyclopropylacetylen werden in 30-g-Maßstab hergestellt und mit n-Butyllithium metalliert. Durch übliche Abfangreagenzien wird eine Vielzahl neuer Verbindungen (11 - 38) erhalten und folgendes gezeigt: 1b wird nur an der Methylgruppe metalliert, 1c sowohl an der Methylengruppe als auch am Cyclopropanring, 1d ausschließlich am Cyclopropanring; zweifache Metallierungen sind selbst unter drastischen Bedingungen nicht nachweisbar.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclic Analogues of Divinylstannanes, Divinylboranes, and pentahapto-Divinylborane ComplexesThe dialkynes X(C ≡ CH)2 with X=(CH3)2C, (CH3)2Si, and (CH2)2 afford the stannacyclodienes X(CH≡CH)2Sn(CH3)2 on hydrostannation with (CH3)2SnH2. These are transformed into the 1-phenylboracyclodienes X(CH=CH)2BC6H5 by treatment with C6H5BCl2. Complexation reactions yield the transition-metal complexes [X(CH=CH)2BC6H5]Fe(CO)3 and (C5H5)Co-[(CH3)2C(CH=CH)2BC6H5] wherein the ligands act as pentahapto-ligands. The structure of tricarbonyl(1,1-dimethyl-4-phenyl-1-sila-4-bora-2,5-cyclohexadiene)iron (6b) is determined by X-ray methods.
    Notes: Die Dialkine X(C ≡ CH)2 mit X — (CH3)2C, (CH3)2Si und (CH2)2 liefern bei der Hydrostannierung mit (CH3)2SnH2 die Stannacyclodiene X(CH=CH)2Sn(CH3)2. Diese werden durch Umsetzung mit C6H5BCl2 in die 1-Phenylboracyclodiene X(CH=CH)2BC6H5 übergeführt. Komplexierungsreaktionen ergeben die Übergangsmetall-Komplexe [X(CH=CH)2BC6H5]Fe(CO)3 und (C5H5)Co[(CH3)2C(CH=CH)2BC6H5], in denen die Boracyclodien-Liganden als pentahapto-Liganden fungieren. Die Struktur von Tricarbonyl(1, 1-dimethyl-4-phenyl-1-sila-4-bora-2,5-cyclo-hexadien)eisen (6b) wird röntgenographisch bestimmt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Perchloro-2-pyrone with Grignard Reagents and Organolithium CompoundsPerchloro-2-pyrone (1) reacts with some Grignard reagents at -10 to -60°C to give the 6-alkyl-substituted pyrones 2a-c. Further reaction of 2a with methylmagnesium bromide leads to the allenediol 4a which is also formed from 1 and methyllithium. Likewise 4b-d are obtainable from 1 and other organolithium compounds. Contrary to methylmagnesium bromide all other investigated Grignard reagents transform 1 into the dihydropyrones 5a-d. - The different reaction courses by 1,2- or 1,4-addition of organometallic compounds to the intermediates 2 are discussed.
    Notes: Aus Perchlor-2-pyron (1) werden mit den entsprechenden Grignard-Reagenzien bei -10 bis -60°C die alkylsubstituierten Pyrone 2a-c erhalten. Die Weiterreaktion von 2a mit Methylmagnesiumbromid führt zu dem Allendiol 4 a, das auch aus 1 und Methyllithium entsteht. In gleicher Weise sind 4b-d aus 1 mit anderen Lithiumorganylen zugänglich. Im Gegensatz zum Methylmagnesiumbromid liefern alle anderen untersuchten Grignard-Verbindungen mit 1 die Dihydropyrone 5. - Der unterschiedliche Reaktionsverlauf einer 1,2- oder 1,4-Addition an die Zwischenstufen 2 wird diskutiert.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Optically Active Transition Metal Complexes, L: Aryl Rotation in C5H5(CO)2Mo-Thioamidato ComplexesIn the thioamidato complexes C5H5(CO)2MoSC(R)NR′ with R′ = CH3, C6H5, CH(CH3)2, CH2C6H5,(S)-CH(CH3)(C6H5), in which R is an o-substituted aryl (2-CH3C6H4,2-CH3OC6H4, or 1-naphthyl), atropisomers A and B can be shown to exist by 1H NMR spectroscopy. The isomers differ in the mutual arrangement of the o-substituent and the C5H5 group. From the trend of the NMR spectroscopically determined barriers for the NSC  -  aryl rotation it follows that the large o-substituent passes by the sulfur atom and that the hindrance to rotation is due to the interaction of the o-hydrogen atom with the NR′group. This is supported by the behaviour of the 2,6-o-di-substituted mesityl complex 4 and by comparison of the thioamidato complexes with corresponding dithiocarboxylato and amidino complexes.
    Notes: In den Thioamidato-Komplexen C5H5(CO)2MoSC(R)NR′ mit R′ = CH3, C6H5, CH(CH3)2, CH2C6H5,(S)-CH(CH3)(C6H5), in denen R ein o-substituierter Aromat (2-CH3C6H4,2-CH3OC6H4 oder 1-Naphthyl) ist, lassen sich 1H-NMR-spektroskopisch Atropisomere A und B nachweisen, die sich in der gegenseitigen Stellung von o-Substituent und C5H5-Rest unterscheiden. Aus dem Gang der NMR-spektroskopisch bestimmten Barrieren für die NSC  -  Aryl-Rotation folgt, daß der große o-Substituent am Schwefelatom vorbeidreht und für die Rotationsbehinderung die Wechselwirkung des o-Wasserstoffatoms mit dem NR′-Rest ausschlaggebend ist. Dies wird durch das Verhalten des 2,6-o-disubstituierten Mesityl-Komplexes 4 und den Vergleich der Thioamidato-Komplexe mit entsprechenden Dithiocarboxylato- und Amidino-Komplexen bestätigt.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...