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  • 1
    Electronic Resource
    Electronic Resource
    Addition von α-Ketoenaminen an 2-Acetyl-p-benzochinon (1993)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 335 (1993), S. 345-350 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of α-Ketoenamines to 2-Acetyl-p-benzoquinoneAddition of 2-morpholino-2-cyclohex-1-en-one 2 to 2-acetyl-quinone 1 yields benzo[c][4 H]chromen-4,7,10-trion 4 which is unstable and rearranges to 5. 4 is converted to 3-(2,5-dihydroxy-phenyl)-2-morpholino-2-cyclohex-1-en-on 3 thermically and to dibenzo[b,d]furan-4-on 7 acid catalyzed. The structure of 7 is secured by independent synthesis. Dibenzo[b,d]furan-4-on 14 is the product of reaction from 2-(p-toluidino)-2-cyclohex-1-en-on 9 and 1 with benzo[c][4 H]chromen-4,7,10-trion 10 as intermediate. By proton catalysis 5-acetyl-6-hydroxy-carbazol-1-on 13 and 4-oxo-cyclohexa[c]isochinolinium hydrochlorid 15 is obtained from 10. 1 H-cyclopenta[d]furan-3-on 17 is formed by addition of 2-(p-toluidino)-2-cyclopent-1-en-on 16 to 1. It is rearranged by proton catalysis to 3-oxo-1 H-cyclopenta[c]isochinolinium salt 18. Reaction of cyclopentan-1,2-dione and 1 yields 3 aH-cyclopenta[c]isochromen-3,6,9-trion 20, rearranging to 1 H-cyclopenta[b]benzo[d]furan-3-on 21. The stereochemistry of adducts is discussed in connection with the course of the reaction, spectroscopical evidence, molecular modelling and calculation of HOMO/LUMO and AO-coefficients.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19933350407
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  • 2
    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
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  • 3
    Electronic Resource
    Electronic Resource
    Eine neue Synthese von 7,8,9,10-Tetrahydrocyclohept[b]indol-6(5H)-onen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2238-2244 
    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 Synthesis of 7, 8, 9,10-Tetrahydrocyclohept[b]indol-6(5H)-onesp-Benzoquinone (5a) and methyl-p-benzoquinone (5b) reacts with N-aryl- and N-alkyl derivatives (4a-f) of 2-(aminomethylene)cyclohexanone to yield 2-hydroxy-5-alkyl- or -aryl-cyclohept-indol-6(5H)-ones 6a-j, the structure of which is proved by spectroscopic and chemical methods. A pathway for the reaction is given. By Fischer Cyclisation of the phenylhydrazone cyclohepta[2,1-b:3,4-b′]diindole 16 is prepared from 6h.
    Notes: p-Benzochinon (5a) und Methyl-p-benzochinon (5b) wurden mit N-Aryl- und N-Alkyl-monosubstituierten 2-(Aminomethylen)cyclohexanonen 4a-f umgesetzt. Die 2-Hydroxy-5-alkyl- bzw. -aryl-cyclohept-indol-6(5H)-on-Struktur 6a-j der Reaktionsprodukte wird spektroskopisch und chemisch bewiesen und ein Reaktionsverlauf angegeben. Durch Fischer-Cyclisierung eines Phenylhydrazons von 6h gelingt die Darstellung des Cyclohepta[2,1-b:3,4-b′]diindols 16.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140620
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Umsetzung von 2-(Aminomethylen)cyclohexanon-Derivaten mit Dichlorchinonen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 152-158 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of 2-(Aminomethylene)cyclohexanone Derivatives with DichloroquinonesReaction of dichloro-p-benzoquinones 1 with 2-[(arylamino)methylene]cyclohexanone derivatives 2 yield dibenzofuranone derivatives 4. The structure is proven spectroscopically and by oxidation to 6, which is hydrolysed to 7. The course of the reaction via the intermediate 10 can be proved by its isolation and reaction to 4a.
    Notes: Durch Umsetzung von Dichlor-p-benzochinonen 1 mit 2-[(Arylamino)methylen]cyclohexanon-Derivaten 2 werden die Dibenzofuran-Abkömmlinge 4 erhalten. Ihre Struktur wird spektroskopisch belegt und durch Oxidation zu 6 sowie anschließende Hydrolyse zu 7 chemisch bewiesen. Der Verlauf der Reaktion über das Zwischenprodukt 10 kann durch dessen Isolierung und Umsetzung zu 4a bewiesen werden.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160118
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  • 5
    Electronic Resource
    Electronic Resource
    Zum Mechanismus der Nenitzescu-Reaktion, V.Synthese von Naphthofuran-Derivaten (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 140-149 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mechanism of the Nenitzescu Reaction, V.  -  Synthesis of Naphthofuran DerivativesThe synthesis of chelated naphthofurans 3 and 4 is described. The structures of 3 and 4 were proved by chemical and spectroscopic methods, and the structure of a by-product has been examined. Possible lactone structures 6 or 7 have been ruled out by independent syntheses. 13C-NMR and UV spectroscopic investigations as well as reductive acetylation to 18 confirmed the structure of 5 as a naphthoquinone derivative. A reaction course for the formation of 3, 4 and 5 is proposed.
    Notes: Die Synthese der chelatisierten Naphthofurane 3 und 4 wird beschrieben und die Struktur mit chemischen und spektroskopischen Methoden bewiesen. Die Struktur eines Nebenproduktes wird untersucht. Die möglichen Lactonstrukturen 6 und 7 werden durch unabhängige Synthese ausgeschlossen. Mit Hilfe der 13C-NMR- und der UV-Spektroskopie, sowie durch reduktive Acetylierung zu 18 wird die Struktur des Naphthochinon-Derivates 5 erkannt. Der Reaktionsablauf der Bildung von 3, 4 und 5 wird skizziert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819780117
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  • 6
    Electronic Resource
    Electronic Resource
    Notiz Untersuchungen zur 6-Hydroxyindol-Bildung bei der Nenitzescu-Reaktion, I Nucleophile Addition an N-Chinonyl-enaminone (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 209-212 
    Details
    ISSN: 0009-2940
    Keywords: Nenitzescu reaction ; Phenoxazine derivatives ; Ring-chain tautomerism ; Enaminone protonation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigation on the Formation of 6-Hydroxyindole in the Nenitzescu Reaction, I Nucleophilic Addition to N-QuinonlyenaminonesN-Quinonyl-enaminone 6 is synthesized. Its transformation into 6-hydroxyindole 5 fails. Thus, structure 6 is no intermediate in the formation of 5 from 1 and 2. Nucleophilic attack of trifluoroacetate on enaminone 6 yields hydroquinone 9a, which is hydrolysed to 10a, b. The structures of 9a and 10a, b are proven spectroscopically and by oxidation of 10b to 11, being equilibrated with phenoxazine 12. The latter is reduced to 13a, b.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220132
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  • 7
    Electronic Resource
    Electronic Resource
    Bemerkungen zur regioselektiven Reaktion von Enaminonen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1601-1602 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Remarks to Regioselectivity of EnaminonesThe 2H-1,5-benzodioxepine structures 3a-c given earlier for the products from 5-amino-4-penten-3-one derivatives 2a-c and p-benzoquinone (1) have to be revised as 2-aminobenzofuran derivatives 5 according to spectroscopic data and chemical transformations.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200921
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  • 8
    Electronic Resource
    Electronic Resource
    Zur Addition von β-Dicarbonylverbindungen an 2-Acetyl-p-benzochinon (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1791-1795 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of β-Dicarbonyl Compounds to 2-Acetyl-pbenzoquinoneThe structure of adducts from 2-acetyl-p-benzoquinone (1) and acetoacetates 2a, b is corrected to dihydrobenzofuran derivatives 4a, b. The product from 1 and hexafluoroacetylacetone 5 is examined spectroscopically and by X-ray structure analysis, its structure is cleared up as [4 + 2] cycloadduct 6. In solution fast rearrangement of 6 to dihydrobenzofuran 13 is observed. Reaction of 13 with acetyl chloride yields the monoacetate 12, treatment with aqueous acid is followed by cleavage to 14. In acetic acid tetralone derivative 16 is formed, which can be aromatized with acetic anhydride to naphthalene 17 and oxidized to naphthoquinone 18.
    Notes: Es wird spektroskopisch belegt, daß die bekannten Addukte 3a, b aus 2-Acetyl-p-benzochinon (1) und Acetessigestern 2a, b in der Dihydrobenzofuran-Struktur 4a, b vorliegen. Die Additionsverbindung von 1 und Hexafluoracetylaceton 5 wird spektroskopisch und röntgenographisch untersucht und die Struktur als [4 + 2]-Cycloaddukt 6 sichergestellt. 6 lagert sich in Lösung spontan zum Dihydrobenzofuran 13 um. Aus 13 läßt sich mit Acetylchlorid das Monoacetat 12 darstellen, während mit wäßriger Säure Spaltung zu 14 erfolgt. In Eisessig entsteht das Tetralon-Derivat 16, das sich mit Acetanhydrid zum Naphthalin-Abkömmling 17 aromatisieren bzw. zum Naphthochinon-Abkömmling 18 oxidieren läßt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871201104
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  • 9
    Electronic Resource
    Electronic Resource
    Untersuchungen zur 6-Hydroxyindol-Bildung bei der Nenitzescu-Reaktion, II: Cyclisierung von N-(Chinonylalkyl)enaminon-Derivaten (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 1493-1498 
    Details
    ISSN: 0009-2940
    Keywords: Spirocyclization ; Quinone cyclization ; Enaminones ; Nenitzescu reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on the Formation of 6-Hydroxyindole in the Nenitzescu Reaction, II.  -  Cyclization of N-(Quinonylalklyl)enaminone DerivativesThe N-(quinonylethyl)enaminones 8a-d are synthesized from the phenylethylamines 5a, b. Quinones 8a, c, d are cyclized to the spiro compounds 9a, c, d. N-(Quinonylmethyl)enaminones 19a, b are obtained from aldehyde 12 via 13, 14, 15 and 16. Enaminone 19a cyclizes spontaneously to spiro compound 20. Ring closure of 19b yields isoquinolinium salts 21a, b. N-(Quinonylpropyl)enaminone 25 is gained from 22 via 23 and 24 and is O-protonated to 26. As shown by model reactions, primary 1,4-addition of enaminone nitrogen to p-benzoquinone is unlikely.
    Notes: Die N-(Chinonylethyl)enaminone 8a-d werden ausgehend von den Phenylethylaminen 5a, b synthetisiert. Die Chinone 8a, c, d werden zu den Spiroverbindungen 9a, c, d cyclisiert. Die N-(Chinonylmethyl)enaminone 19a, b werden aus dem Aldehyd 12 über 13, 14, 15 und 16 dargestellt. 19a cyclisiert spontan zur Spiroverbindung 20. Der Ringschluß von 19b ergibt die Isochinolinium-Salze 21a, b. Das N-(Chinonylpropyl)enaminon 25 wird aus 22 über 23 und 24 erhalten und zu 26 O-protoniert. Die Modellreaktionen zeigen, daß eine primäre 1,4-Addition des Enaminon-Stickstoffs am p-Benzochinon wenig wahrscheinlich ist.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220821
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  • 10
    Electronic Resource
    Electronic Resource
    Zur Umsetzung von 2-Amino-2-cyclopenten-1-on-Derivaten mit p-Benzochinon (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3487-3491 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of 2-Amino-2-cyclopenten-1-one Derivatives and p-Benzoquinoneα-Ketoenamines 3a and b react with p-benzoquinone (2) to yield benzoxazepine derivatives 5 and 6. Intermediate 7a is isolated and transformed to 5b. The course of the reaction is discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191124
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