ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
Filter
  • Chemistry  (159)
  • Inorganic Chemistry  (43)
  • 1
    Electronic Resource
    Electronic Resource
    Alcoholysis of Aluminum Alkyls Supported by Bulky Phenoxide Ligands: Synthesis, Characterization, and ε-Caprolactone Polymerization Activity of Two Dimeric Aluminum Isopropoxides (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 441-445 
    Details
    ISSN: 1434-1948
    Keywords: Aluminum ; Alkoxides ; Lactone ; Ring-opening ; Polymerization ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of trialkylaluminum Al2R6 (R = Me, Et) with 2,2′-methylenebis(6-tert-butyl-4-methylphenol) (mbmpH2) gives the dimeric mono(alkyl) complex [Al(mbmp)R]2 with bridging oxygen atoms. Reaction of [Al(mbmp)R]2 with one equiv. of 2-propanol results in the formation of the dimeric isopropoxide [Al(mbmp)(μ-OiPr)]2. Single-crystal X-ray analysis shows a C2h-symmetric structure with a planar Al2O2 core. Monomeric methylbis(2,6-di-tert-butyl-4-methylphenolato)aluminum, AlMe(OC6H2-2,6-tBu2-4-Me)2 (MAD), was found to react with one equiv. of 2-propanol to give a dimeric isopropoxide [AlMe(OC6H2-2,6-tBu2-4-Me)(μ-OiPr)]2 in which the bulky phenolate, instead of the methyl group, has been displaced. According to the single-crystal X-ray structure analysis, the molecule contains a similar Al2O2 core, but the two 2,6-di-tert-butyl-4-methylphenolato ligands are cis- and orthogonally arranged to each other. ε-Caprolactone is polymerized at 50 °C in toluene in a controlled manner by [Al(mbmp)(μ-OiPr)]2, to give poly(ε-caprolactone) with high molecular weights and narrow molecular weight distributions (Mw/Mn 〈 1.50). The low efficiency values (number of polymer chains initiated per aluminum atom) imply that [Al(mbmp)(μ-OiPr)]2 exists in a monomer-dimer equilibrium. The polymerization of ε-caprolactone by [AlMe(OC6H2-2,6-tBu2-4-Me)(μ-OiPr)]2 is faster, but somewhat less controlled.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of Gallane-Amine adducts as potential precursors for GaAs and (AlGa)as MOVPE processes and the crystal structure of the {gallane · 1,3-bis(dimethylamino)propane} adduct H3Ga · N(CH3)2(CH2)3N(CH3)2 (1992)
    Weinheim : Wiley-Blackwell
    Advanced Materials 4 (1992), S. 576-579 
    Details
    ISSN: 0935-9648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adma.19920040911
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Synthese und Konformationsanalyse von Pyranophanonen und Pyrylophanium-Verbindungen mit intraannularen Substituenten (1993)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 335 (1993), S. 503-514 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Conformational Analysis of Pyranophanones and Pyrylophanium Compounds with Intraannular SubstituentsThe synthesis of [3.3]dithiapyranophanone 6 and 11 is accomplished by use of the two-components-dilution-principle. Pyrolysis of their bis(sulfones) 7 and 12 gives the [2.2]pyranophanones 8, 9 and 13. Under preservation of conformation the intraannular carbonyl-function is used for the synthesis of methylpyranophanoles 14, 16 and 17. The synthesis of pyrylophanium compounds 15 and 18 is possible by elimination in trifluoroacetic acid.6 exhibits anti-conformation within its crystal-structure and like 7 reveals temperature-dependent behavior in solution. Using 6 as an example, a combination of 13C-NMR-spectroscopy, forcefield-calculation and computer-simulation is applied for the first time to give evidence for molecular-dynamic processes of cyclophanes.8 and 9 are the syn- and anti-conformers of the desired product, as shown by X-ray structural analysis. 13 reveals anti-conformation within its crystal structure as well as in solution. The conformational analysis of other new phanes described here is based on the 1H-NMR-spectra of these pyrolysis products.As expected the intraannular substituents of Pyrylophanium-lons 15 and 18 show the characteristic upfield-shift within their 1H-NMR-spectra.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19933350603
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Reactions of 3,5-Diaryl-1,2-dithiolium Salts and 3,5-Diaryl-1,2,4-dithiazolium Salts with Metal Cyclopentadienides (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 221-228 
    Details
    ISSN: 0947-3440
    Keywords: 3,5-Diaryl-1,2-dithiolium salts ; 3,5-Diaryl-1,2,4-dithiazolium salts ; Metal cyclopentadienides ; 3,7-Dithiatricyclo[4.4.0.02,8]deca-4,9-diene ; 3,5-Dithiatricyclo[4.2.2.02,6]deca-7,9-diene ; 3,7-Dithia-5-azatricyclo[4.4.0.02,8]deca-4,9-diene ; Diels-Alder reactions ; Nitrogen heterocycles ; Sulfur heterocycles ; Polycycles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of the 3,5-diaryl-1,2-dithiolium salts 2 with the metal cyclopentadienides 4 and 9 leads to the formation of the tricyclic compounds 6 and 10 via a ring-opened intermediate, which undergoes an intramolecular Diels-Alder cyclization. Compounds 6 and 10 rearrange by treatment with boron trifluoride-diethyl ether to the isomeric compounds 7 and 11. The structures 6f and 7f were confirmed by X-ray analysis. Condensation of the 3,5-diaryl-1,2,4-dithiazolium salts 3 with the metal cyclopentadienides 4 affords the tricyclic compounds 12, which do not rearrange by Lewis acid catalysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970133
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Positional and Facial Selectivity in Diels-Alder Reactions of (-)-(aS,7S)-Colchicine: Synthesis of Novel Analogues of the Alkaloid (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 851-857 
    Details
    ISSN: 0947-3440
    Keywords: Colchicine, diene properties of ; Positional selectivity ; Stabilized exciplex through hydrogen bonding ; π-Facial diastereoselectivity ; Photooxygenation ; Solvent effects ; Cycloadditions ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positional and facial selectivity in Diels-Alder reactions of several hetero- and carbodienophiles with (-)-(aS,7S)-colchicine (1) has been examined. In all cases, cycloaddition occurred with high positional selectivity at the 8,12-positions of the alkaloid and preferentially from the diene face syn to the allylic substituent at the stereogenic center C-7. The observed high π-facial diastereoselectivity is independent of the polarity of the solvent used and is therefore probably a consequence of steric factors. The structures of the Diels Alder-adducts of 1 with singlet oxygen, N-phenyl-1,2,4-triazolinedione (PTAD) and trans-cyclooctene, 4,5, and 15, respectively, were assigned on the basis of spectral data and verified by X-ray crystallography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970510
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Aminyloxide (Nitroxide), XXXV. Das tricyclische Dimere eines Vinylaminyloxids (Vinylnitroxids) und seine Isomerisierung zu einem 2,4,7,9-Tetraoxa-5,10-diazatetracyclo[4.4.2.03,12. 08,11]dodecan (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2615-2621 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminyl Oxides (Nitroxides), XXXV. The Tricyclic Dimer of a Vinyl Aminyl Oxide (Vinyl Nitroxide) and its Isomerization to give a 2,4,7,9-Tetraoxa-5,10-diazatetracyclo[4.4.2.03,12.08,11]dodecaneVinyl aminyl oxide 6 is formed by oxidation of hydroxylamine 3 via the intermediates 4 and 5. Dimerization of 6 yields the tricyclic compound 8. In solution dissoziation of 8 occurs at approximately 40°C, four bonds being cleaved to afford radical 6. By prolonged heating in various solvents as well as by proton catalysis at room temperature 8 is rearranged to give the tetracyclic isomer 9, the structure of which has been confirmed by X-ray analysis.
    Notes: Das Vinylaminyloxid 6 entsteht bei der Oxidation des Hydroxylamins 3 über die Zwischenstufen 4 und 5. 6 dimerisiert unter Bildung der tricyclischen Verbindung 8. 8 dissoziiert in Lösung bereits bei etwa 40°C unter Spaltung von vier Bindungen in das Radikal 6. Durch längeres Erhitzen in verschiedenen Lösungsmitteln, aber auch unter Protonenkatalyse bei Raumtemperatur, wird 8 in ein tetracyclisches Isomeres 9 umgewandelt. Die Struktur von 9 wurde durch Röntgenstrukturanalyse ermittelt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Bildung und Umlagerung von cyclischen Halbaminalen mit einer α-Mercapto-Struktur (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3405-3415 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation and Rearrangement of Cyclic Semi-aminals with α-Mercapto GroupsReaction of thioacetic acid, thiobenzoic acid as well as 2-aminothiophenol with racemic cyclic semi-aminal 3 takes a diastereoselective course to racemic 4a, b, c. The ambident thiazolidine-2-thione reacts analogously, however by attack of nitrogen yielding 4d. The possibilities for rearrangement of adducts 4 are discussed and the structure of the rearranged products is examinated by x-ray analysis of 9c as well as by 13C NMR spectroscopy. The course of the diastereoselective rearrangement to the racemic mixture (α/β) of 2-azaspiro[4.4]nonenes 9a - d is discussed by aid of the results.
    Notes: Die Reaktion von Thioessigsäure, Thiobenzoesäure und 2-Aminothiophenol mit dem racemischen cyclischen Halbaminal 3 erfolgt diastereoselektiv unter Erhaltung der Halbaminal-Struktur zu den Racematen (α/β) 4a, b, c. Das ambidente Thiazolidin-2-thion setzt sich analog, jedoch unter Anlagerung des Stickstoff-Atoms, zu 4d um. Die Umlagerungsmöglichkeiten der Addukte 4 werden diskutiert, und die Struktur der Umlagerungsprodukte wird durch eine Röntgenstrukturanalyse am Beispiel des Aminophenylthio-Derivates 9c sowie 13C-NMR-spektroskopisch untersucht. Der Verlauf der diastereoselektiven Umlagerung zu den racemischen (α/β) 2-Azaspiro[4.4]-nonen-Derivaten 9a - d wird an Hand der Ergebnisse diskutiert.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801131102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Stereoselektive Synthese von Alkoholen, IX. Absolute Konfiguration von Stegobinon (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2786-2801 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereoselective Synthesis of Alcohols, IX. Absolute configuration of StegobinoneDiastereoselective as well as enantioselective conversion of the boronate 4 into the homoallyl alcohol 5 served as basis for the synthesis of optically active stegobinone isomers. Material with the correct absolute configuration at C-2 was obtained starting from (3S)-3-hydroxy-2-methyl-butyrate 17. The CD spectrum of the isomer 20B corresponded to that of the natural product. Its Configuration was assigned as 2S, 3R, 7R and was substantiated by an X-ray structure determination of 7-epistegobinone (20A).
    Notes: Eine diastereo- und enantioselektive Synthese des Homoallylalkohols 5 aus dem Boronester 4 eröffnete den Zugang zu optisch aktiven Isomeren des Stegobinons. Stegobinon-Isomere mit der richtigen absoluten Konfiguration an C-2 wurden ausgehend von (3S)-3-Hydroxy-2-methylbuttersäureester 17 dargestellt. Das CD-Spektrum des Isomeren 20B entsprach dem des Naturstoffs. Daraus wurde die konfiguration zu 2S, 3R, 7R für das natürliche Stegobinon abgeleitet und durch eine Röntgenstrukturanalyse des 7-Epistegobinons (20A) erhärtet.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140811
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Zur Kenntnis von Reaktionen des 1,2,4,5-Tetrazin-3,6-dicarbonsäure-dimethylesters mit Nucleophilen (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 683-694 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Dimethyl 1,2,4,5-Tetrazine-3,6-dicarboxylate with NucleophilesThe reaction of water, ammonia or dimethylamine with the tetrazine 1 leads via 1,4-addition of the nucleophile to the hydrazide 4 and the azines 6, 7, respectively. Contrarily methylamine yields the triazine 13. Methanol or methanethiol react to the pyrazoles 19 and 18, respectively. The structure of 18 is proved by X-ray diffraction. Depending on the p-substituents, anilines give triazoles 22 or pyrazolo[3,4-e]triazines 24.
    Notes: Die Reaktion von Wasser, Ammoniak oder Dimethylamin mit dem Tetrazin 1 führt unter 1,4-Addition des Nucleophils zum Hydrazid 4 bzw. zu den Azinen 6 und 7. Mit Methylamin entsteht im Gegensatz dazu das Triazin 13. Methanol oder Methanthiol reagieren zu Pyrazolderivaten 19 bzw. 18. Die Struktur von 18 wird durch eine Röntgenstrukturanalyse belegt. para-Substituierte Aniline lassen sich je nach p-Substituent in Triazole 22 oder Pyrazolo[3,4-e]triazine 24 überführen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821150228
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Pseudooxokohlenstoff-Dianionen der C4-Reihe mit Dicyanmethylenfunktionen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2714-2729 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pseudooxocarbon Dianions of the C4-Series with Dicyanomethylene GroupsReaction of suitable activated squaric acid derivatives with the anion of malononitrile yields pseudooxocarbon dianions of the C4-series 5 - 9, in which the oxygens are successively replaced by one, two, three, or four dicyanomethylene groups. Besides the synthesis of mixed substituted pseudooxocarbon monoanions such as 11 and 21 is reported. Spectroscopic data are discussed, 13C NMR data together with those of pseudooxocarbon dianions of the C3- and C5-series. The structure of 9c is proved by X-ray diffraction and the cyclic bond-delocalized system compared with those of the squarate und tetrathiosquarate dianion.
    Notes: Durch Reaktion geeignet aktivierter Quadratsäurederivate mit dem Anion des Malononitrils werden Pseudooxokohelenstoff-Dianionen der C4-Reihe 5 - 9 synthetisiert, in denen die Sauerstofffunktionen sukzessive durch ein, zwei, drei oder vier Dicyanmethylenfunktionen ersetzt sind. Daneben wird über die Synthese gemischt substituierter Pseudooxokohlenstoff-Monoanionen wei 11 und 21 berichtet. Spektroskopische Daten werden diskutiert, 13C-NMR-Daten mit denen von Pseudooxokohlenstoff-Dianionen der C3-Reihe verglichen. Die Struktur von 9c wird durch eine Röntgenstrukturanalyse belegt und dessen cyclisches, bindungsdelokalisiertes System mit dem des Quadratats und des Tetrathioquadratats verglichen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170815
    Location Call Number Expected 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...