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  • 1
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    Ineupatoriol, a thiophene analogue of ichthyothereol, from Inula eupatorioides (1982)
    Elsevier
    Details
    Publication Date: 1982-01-01
    Print ISSN: 0031-9422
    Electronic ISSN: 1873-3700
    Topics: Biology , Chemistry and Pharmacology
    Published by Elsevier
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    PAPER CURRENT
  • 2
    Electronic Resource
    Electronic Resource
    Protonenresonanz-Spektroskopie ungesättigter Ringsysteme, XXVII. Der Benzolkern als Sonde für die π-Elektronenstruktur von Annulenen; Teil IV: Dehydrobenzoannulene (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 71-83 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Proton Resonance Spectroscopy of Unsaturated Ring Systems, XXVII. The Benzene Nucleus as a Probe for the π-Electronic Structure of Annulenes; Part IV: DehydrobenzoannulenesThe 1H NMR Spectra of 6,9-dimethyl-7-monodehydrobenzo[12]annulene (1), 7,9-bisdehydrobenzo[14]annulene (2a), 6,11-dimethyl-7,9-bisdehydrobenzo[14]annulene (2a), 6,11-dimethyl-7,9-bisdehydrobenzo[16]annulene (3), and 9,11-bisdehydrobenzo[18]annulene (4) have been analyzed with respect to chemical shifts and H,H coupling constants. The electronic ground state properties of the annulene rings have been investigated using the Q-value method2). On the basis of the chemical shifts it was found that, compared to the free bisdehydroannulenes, the diatropic behaviour of 2a and 4 is reduced by ca. 70-80%, whereas the paratropic nature of 3 is diminished by less than 50%. Strong π-bond fixation exists in the annulene rings of 1-4.The conformations of the systems are discussed.
    Notes: Die 1H-NMR-Spektren von 6,9-Dimethyl-7-monodehydrobenzo[12]annulen (1), 7,9-Bisdehydrobenzo[14]annulen (2), 6,11-Dimethyl-7,9-bisdehydrobenzo[14]annulen (2a), 6,11-Dimethyl-7,9-bisdehydrobenzo[16]annulen (3) und 9,11-Bisdehydrobenzo[18]annulen (4) wurden hinsichtlich chemischer Verschiebungen und H,H-Kopplungskonstanten analysiert. Die elektronischen Eigenschaften des Grundzustandes der Annulenringe wurden mit Hilfe der Q-Wert-Methode2) untersucht. Aus den chemischen Verschiebungen wurde abgeleitet, daß das diatrope verhalten von 2a und 4 im Vergleich zu dem der freien Bisdehydroannulene um ca. 70-80% reduziert ist, während das paratrope Verhalten von 3 um weniger als 50% abgenommen hat. In den Annulenringen von 1-4 liegt eine starke π-Bindungsfixierung vor. Die Konformationen der Systeme werden diskutiert.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120107
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  • 3
    Electronic Resource
    Electronic Resource
    Protonenresonanz-Spektroskopie ungesättigter Ringsysteme, XXVI.Der Benzolkern als Sonde für die π-Elektronenstruktur von Annulenen; Teil III: Dibenzoannulene und Dibenzoannulen-Ionen (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 165-175 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Proton Resonance Spectroscopy of Unsaturated Ring Systems, XXVI1).  -  The Benzene Nucleus as a Probe for the π-Electronic Structure of Annulenes; Part III: Dibenzoannulenes and Dibenzoannulene IonsThe Q-value method for the classification of cyclic π-systems [D. Cremer and H. Günther, Liebigs Ann. Chem. 763, 87 (1972)] is applied to dibenzoannulenes and dibenzoannuleneions. For this purpose the 1H NMR spectra of 1,2,5,6-dibenzocycloocta-1,5-diene-3,7-diyne (1), 1,2,5,6-dibenzocyclooctenediide (5) 1,2,3,4-dibenzocyclooctene (6), and 1,2,3,4-dibenzocyclooctenediide (7) have been completely analyzed. Antiaromatic (4n) character is found for 1. The problems associated with the interpretation of proton resonance frequencies in dehydroannulenes are discussed.
    Notes: Die Q-Wert-Methode zur Klassifizierung cyclischer π-Systeme [D. Cremer und H. Günther, Liebigs Ann. Chem. 763, 87 (1972)] wird auf Dibenzoannulene und Dibenzoannulen-Ionen angewandt. Dazu wurden die 1H-NMR-Spektren von 1,2,5,6-Dibenzocycloocta-1,5-dien-3,7-diin (1), 1,2,5,6-Dibenzocyclooctendiid (5), 1,2,3,4-Dibenzocycloocten (6) und 1,2,3,4-Dibenzocyclooctendiid (7) komplett analysiert. Für 1 wurde antiaromatischer (4n) Charakter gefunden. Die Problematik der Interpretation von Protonenresonanzfrequenzen bei Dehydroannulenen wird diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819780119
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  • 4
    Electronic Resource
    Electronic Resource
    1,5-Sigmatrope Umlagerung von Diels-Alder-Addukten bei der Reaktion von Alkatrienphosphonaten mit Acetylencarbonsäureestern - Ein neuer Weg zur Synthese von Benzyl- und Phenylphosphonaten (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1381-1386 
    Details
    ISSN: 0009-2940
    Keywords: Diels-Alder reaction ; Vinyl allenes ; Acetylenecarboxylates ; Phosphonates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,5-Sigmatropic Rearrangements of Diels-Alder Adducts in the Reaction of Alkatrienylphosphonates with Alkyl Acetylenecarboxylates - A New Method for the Synthesis of Benzyl- and PhenylphosphonatesThe reaction of dialkyl (3-methyl-1,2,4-pentatrienyl)- and dialky] (3-methyl-1-vinyl-1,2-butadienyl)phosphonic acids 1a-d an 5a, b, respectively, with alkyl esters of the acetylenecarboxylic acids 2a-d proceeds via 1,5-sigmatropic rearrangement and aromatization of the initially formed Diels-Alder adducts. The reaction with the unsymmetrical dienophiles 2a, b occurs with preferred formation of the cycloadducts A, leading to the benzylphosphonates 3a-h. The above reaction constitutes a new method for the preparation of difficulty accessible derivatives of the benzyl- and phenylphosphonic acids. The aromatic structures of the obtained compounds 3a-h, 4a-f, and 6a-d were proved by their IR, mass, and 1H-NMR spectra.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230630
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  • 5
    Electronic Resource
    Electronic Resource
    Untersuchung zur Regio- und Stereoselektivität der Reaktion von 7,8-Dimethoxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepin mit Phenyloxiranen (1991)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 333 (1991), S. 923-930 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of Benzazepines with PhenyloxiranesThe reaction between the 7,8-dimethoxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepines ( ± )-1, (1S)-(-)- 1 und (1R)-( + )- 1 and racemic or optically active phenyloxiranes 2a-d leads to a mixture of the regioisomcric carbinoles 3a-d and 4a-d, respectively. In all cases the reaction is not stereospecific, but regiospecific with regard to the p-phenyl substituted phenyloxiranes 2b-d. The ratio of the isomers was determined by HPLC and the structures of the regioisomers 3a and 4a were deduced from the 1H-n.m.r. spectra. The newly synthesized carbinols proved to be strong re-uptake in hibitors of the monoamines dopamine (DA), norepinephrine (NE) and serotonine (5-HT).
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19913330616
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  • 6
    Electronic Resource
    Electronic Resource
    Verbesserte Synthese von 8-Amino-2-methyl-4-phenyl-1,2,3,4-Tetrahydroisochinolin (1989)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 331 (1989), S. 731-735 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An Improved Synthesis of 8-Amino-2-methyl-4-phenyl-1,2,3,4-TetrahydroisoquinolineThe regioselectivity of the reaction of 2-nitrobenzylmethylamine (1) and styrenoxide (2) leading to a mixture of the isomeric aminoalcohols 3a and 3b has been studied. The course of the reaction strongly depends on the type of the solvent used as reaction medium. The highest selectivity (3a:3b = 9:1) was achieved with a combination of polar aprotic and protic solvents (DMFA and ethanol). 1H n.m.r. spectroscopy was used for identification of the isomers as well as for the determination of their ratio in the crude reaction mixtures. The isomer ratio remains unaffected during catalytic reduction (Ra-Ni) of 3a/3b to a mixture of the corresponding aminoalcohols 4a and 4b. Pure 3a, 4a and 4b were independently synthesized for comparison. Cyclodehydration of crude 4a/4b mixtures gives 5 in a very good yield.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19893310505
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