Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Geminal vinyl diazides. 8. Substituent-dependent competition between 1,5- and 1,5'-cyclization of vinyl azides. 1,2,3-Triazoles and 4,5-dihydro-1H-tetrazol-5-ylidenes from methyl 3,3-diazido-2-cyanoacrylate with amines (1989)
    s.l. : American Chemical Society
    The @journal of organic chemistry 54 (1989), S. 4356-4359 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00279a024
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Conjugate reduction vicinal to butadiene tricarbonyl iron complexes. Application to the synthesis of (.+-.)-6,7-dihydro-LTB4 methyl ester (1992)
    s.l. : American Chemical Society
    The @journal of organic chemistry 57 (1992), S. 3359-3364 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00038a026
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Molecular jail-making (1996)
    [s.l.] : Nature Publishing Group
    Nature 383 (1996), S. 124-125 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] ONE of the most interesting features of buckminsterfullerene, or C60 (part a of the figure), is its 7-A-diameter internal cavity, which can act as a container for atoms, and provides a potential environment for endohedral chemistry (chemistry inside the cage). Making and isolating these complexes ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/383124a0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Exploring {2}-Metallacryptands and {2}-Metallacryptates with Quantum Chemical Methods - When (not only) Computer Chemists’ Dreams Come True (2000)
    Springer
    Journal of molecular modeling 6 (2000), S. 126-132 
    Details
    ISSN: 0948-5023
    Keywords: Keywords Supramolecular chemistry, Metallacryptates, Semiempirical calculations, Sparkles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Semiempirical PM3 computations are reported for the {2}-gallium cryptand and {2}-gallium cryptates with three 2,6-bis(acetylaceto)pyridine ligands. Optimized “sparkles” are employed for the description of metal ion guests for which no PM3 parameters are available. Calculated structures agree well with available X-ray structures of the corresponding {2}-iron cryptates. The trend in the computed complexation energies of the guest metal ions, compared to solvent complexes, agrees with experimental findings: for experimentally known complexes, exothermic exchange is computed, while endothermic exchange is calculated for cryptates that could not be synthesized. In the case of lead, the predicted favorable cryptate formation subsequently was verified experimentally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s0089400060126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Kumulierte Ylide, I. Darstellung des (2,2-Diäthoxyvinyliden)triphenylphosphorans und seine Umsetzung mit Fluorenon (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 2601-2609 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cumulated Ylides, I. Synthesis of (2,2-Diethoxyvinylidene)triphenylphosphorane and its Reaction with Fluorenone(Ethoxycarbonylmethylene)triphenylphosphorane (3) reacts with triethyloxonium tetra-fluoroborate by O-alkylation to give (2,2-diethoxyvinyl)trlphenylphosphonium tetrafluoro-borate (6), which under appropriate conditions can act as an alkylating agent. Treatment of 6 with sodium amide yields (2,2-diethoxyvmylidene)triphenylphosphorane (9), which with fluorenone affords the immediately dimerizing fluorenylideneketene acetal 13. Degradation experiments show that the dimer has the structure 14.
    Notes: Die Umsetzung des (Äthoxycarbonylmethylen)triphenylphosphorans (3) mit Triäthyl-oxoniurn-tetrafluoroborat ergibt durch O-Alkylierung das (2,2-Diäthoxyvinyl)triphenyl-phosphonium-tetrafluoroborat (6), das unter geeigneten Bedingungen als Alkylierungsmittel reagieren kann. Durch Einwirkung von Natriumamid auf 6 erhält man das (2,2-Diäthoxy-vinyliden)triphenylphosphoran (9), das mit Fluorenon zum sofort dimerisierenden Fluoren-ylidenketenacetal 13 reagiert. Dem Dimeren konnte aufgrund von Abbaureaktionen die Struktur 14 zugeordnet werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731060823
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Kumulierte Ylide, III1) Michael-Addition von Carbonylverbindungen an (Diäthoxy-vinyliden)triphenylphosphoran. Eine Synthesemöglichkeit für γ,δ-ungesättigte 1,3-Dicarbonylverbindungen (1976)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 403-410 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cumulated Ylids, III1) Michael Addition of Carbonyl Compounds to (Diethoxyvinylidene)triphenylphosphorane. A Synthesis of γ, δ-Unsaturated 1,3-Dicarbonyl Compounds and their Enol Ethers.(Diethoxyvinylidene)triphenylphosphorane (1) reacts with carbonyl compounds 2, carrying a CH2-group in α-position, in a Michael addition-type reaction followed by elemination of ethanol to give the phosphoranes 5. Wittig reaction of 5 with aldehydes leads to the enol ethers 10. Treatment of 10 with acids gives rise to γ, δ-unsaturated 1,3-dicarbonyl compounds 11 or 2,3-dihydro-4-pyrones 14. With ethanolic potassiumhydroxide solution the compounds 14 are converted into 11.
    Notes: (Diäthoxyvinyliden)triphenylphosphoran (1) reagiert mit Carbonylverbindungen 2, die in α-Stellung eine CH2-Gruppe traten, unter Michael-Addition und anschließender Abspaltung von Äthanol zu den Phosphoranen 5. Die Witting-Reaktion von 5 mit Aldehyden 9 führt zu Enoläthern 10, deren Spaltung mit Säuren γ,δ-ungesättigte 1,3-Dicarbonylverbindungen 11 oder 2,3-Dihydro-4-pyrone 14 liefert. Die Verbindungen 14 werden durch äthanolische Kaliumhydroxidlösungen in 11 verwandelt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19761090141
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Das Photoelektronenspektrum von 1,1-Diethoxy-3,3-bis(trifluormethyl)allen. Der Effekt von Trifluormethylgruppen auf kumulierte Systeme (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2888-2895 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Photoelectron Spectrum of 1,1-Diethoxy-3,3-bis(trifluoromethyl)allene. The Effect of Trifluoromethyl Groups on Cumulative SystemsThe He(I) photoelectron(PE) spectra of 1,1-diethoxy-4,4,4-trifluoro-3-(trifluoromethyl)-1,2-butadiene [1,1-diethoxy-3,3-bis(trifluoromethyl)allene] (1), tetraethoxyallene (3), and tetrakis-(trifluoromethyl)allene (5) have been recorded. A comparison between the PE spectra of 1, 3, and 5 shows that the first band of 1 (8.93 eV) is due to an ionization from the diethoxyethylene fragment and the second band of 1 (11.0 eV) is due to ionization from the bis(trifluoromethyl)-ethylene fragment. The effect of CF3 groups has also been discussed by comparing the PE spectra of bis(trifluoromethyl)ketene (6) and bis(trifluoromethyl)thioketene (7) with the parent compounds. The interpretation is aided by comparing the measured ionization potentials with orbital energies derived from a MINDO/3 or MNDO calculation.
    Notes: Die He(I)-Photoelektronen(PE)-Spektren von 1,1-Diethoxy-4,4,4-trifluor-3-(trifluormethyl)-1,2-butadien [1,1-Diethoxy-3,3-bis(trifluormethyl)allen] (1), Tetraethoxyallen (3) und Tetrakis-(trifluormethyl)allen (5) wurden gemessen. Der Vergleich zwischen den PE-Spektren von 1, 3 und 5 zeigt, daß das 1. Ionisationspotential von 1 (8.93 eV) der Ionisation aus dem Diethoxyethylen-Fragment, das 2. Ionisationspotential von 1 (11.0 eV) der Ionisation aus dem Bis(trifluormethyl)ethylen-Fragment entspricht. Der Effekt der CF3-Gruppen wird zusätzlich anhand eines Vergleichs der PE-Spektren von Bis(trifluormethyl)keten (6) und Bis(trifluormethyl)thioketen (7) mit den unsubstituierten Verbindungen diskutiert. Die Interpretation erfolgt durch Vergleich zwischen den gemessenen Ionisationspotentialen und berechneten Orbitalenergien nach der MINDO/3-oder MNDO-Methode.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160815
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Butenolid-Synthesen, II. Einfache Synthese von 4-substituierten 2,2-Diethoxy-5-alkyliden-2,5-dihydrofuranen, 3-substituierten 4-Alkyliden-2-buten-4-oliden bzw. 5,6-Dihydro-2-pyronen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3482-3486 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Butenolide Syntheses, II. Simple Synthesis of 4-Substituted 2,2-Diethoxy-5-alkylidene-2,5-dihydrofurans, 3-Substituted 4-Alkylidene-2-butene-4-olides or 5,6-Dihydro-2-pyonesReaction of the (2,2-diethoxyvinylidene)triphenylphosphorane (5) with enolizing 1,2-diketones 3 via the (2,2-diethoxyvinyl)triphenylphosphonium enolates 6 yields the orthoesterphosphoranes 7, which in an intramolecular Wittig reaction spontaneously give the orthoesters 8, whose acidic hydrolysis affords the 4-alkylidene-2-butene-4-olides 4. - Under appropriate conditions 5 reacts with 3 to give also 4-acetyl-6-(1,1-diethoxyethyl)-5,6-dihydro-6-methyl-2-pyrone (12). 12 is formed via a four step reaction cascade by coupling of aldol addition, Michael addition, Wittig reaction and orthoester-ketone/ester-ketal interconvertion.
    Notes: Bei der Umsetzung von (2,2-Diethoxyvinyliden)triphenylphosphoran (5) mit den enolisierenden 1,2-Diketonen 3 entstehen über die (2,2-Diethoxyvinyl)triphenylphosphonium-enolate 6 die Orthoesterphosphorane 7. Diese liefern spontan in einer intramolekularen Wittig-Reaktion die Orthoester 8, deren saure Hydrolyse glatt zu den 4-Alkyliden-2-buten-4-oliden 4 führt. - Unter geeigneten Reaktionsbedingungen gelingt aus 5 und 3 außerdem die Synthese von 4-Acetyl-6-(1,1-diethoxyethyl)-5,6-dihydro-6-methyl-2-pyron (12). 12 entsteht über eine vierstufige Reaktionskaskade durch Kopplung von Aldol-Addition, Michael-Addition, Wittig-Reaktion und Orthoester-Keton/Ester-Ketal-Umwandlung.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831161020
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Synthesen mit Alkendiazoniumsalzen, III. ω,ω′-Di-1H-1,2,3-triazolylalkane aus Ethendiazonium- hexachloroantimonaten und ω,ω′-Diaminoalkanen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1246-1249 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses with Alkenediazonium Salts, III. ω,ω′-Di-1H-1,2,3-triazolylalkanes from Ethenediazonium Hexachloroantimonates and ω,ω′-DiaminoalkanesReaction of the ethenediazonium hexachloroantimonates 2 with ω,ω′-diaminoalkanes 3 leads to ω,ω′-di-1H-1,2,3-triazolylalkanes 5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170337
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Synthesen mit Alkendiazoniumsalzen, IV. 1H-1,2,3-Triazole, 2-Diazoimine und Imidoester aus Alkendiazoniumsalzen mit primären Aminen, Hydrazinen und Hydroxylaminethern (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2626-2634 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Alkenediazonium Salts, IV 1H-1,2,3-Triazoles, 2-Diazoimines, and Imido Esters from Alkenediazonium Salts and Primary Amines, Hydrazines, and Hydroxylamine EthersReaction of alkenediazonium salts 1 with „amines“ 2 (primary amines, hydrazines, hydroxylamine ethers) leads to 2-diazoimines 4, 1H-1,2,3-triazoles 6, and imido esters 8 and 9, respectively, depending on the substituents R. Condensation of 1-amino-1H-1,2,3-triazole 6Ceα with acetone yields hydrazone 13.
    Notes: Die Umsetzung von Alkendiazoniumsalzen 1 mit „Aminen“ 2 (primäre Amine, Hydrazine, Hydroxylaminether) führt in Abhängigkeit der Substituenten R zu 2-Diazoiminen 4, 1H-1,2,3-Triazolen 6 bzw. Imidoestern 8 und 9. Kondensation von 1-Amino-1H-1,2,3-triazol 6 Ceα mit Aceton liefert das Hydrazon 13.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180706
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...