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  • 1
    Electronic Resource
    Electronic Resource
    A 13C13C spin-spin coupling matrix for azulene (1984)
    s.l. : American Chemical Society
    The @journal of organic chemistry 49 (1984), S. 3725-3728 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00194a011
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  • 2
    Electronic Resource
    Electronic Resource
    Azulene-naphthalene rearrangement. Involvement of 1-phenylbuten-3-ynes and 4-phenyl-1,3-butadienylidene (1980)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 102 (1980), S. 5110-5112 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00535a056
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  • 3
    Electronic Resource
    Electronic Resource
    Zu den Umlagerungsreaktionen des Acetyl-benzoylcarbens (1979)
    Springer
    Monatshefte für Chemie 110 (1979), S. 393-399 
    Details
    ISSN: 1434-4475
    Keywords: Carbene-carbene rearrangement ; Oxirene participation ; Photolysis, [2-13 C] 1-phenyl-2-diazo-1,3-butadione ; Wolff rearrangement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Labelled acetyl-benzoylcarbene (13) formed by photolytic nitrogen elimination from [2-13C]1-phenyl-2-diazo-1,3-butadione (8) rearranges in the presence of ethanol to ethyl 2-phenylacetoacetate (26%) and ethyl 2-benzoylpropionate (74%). The13C-labelling in ethyl 2-phenylacetoacetate is found to the extend of ca.58% in the ester carbonyl function (20) and to ca. 42% in the adjacent tertiary carbon atom (21). This proves the isomerisation of carbene13 to carbene11 via the intermediate acetyl-phenyloxirene (12). The [1-13C]-labelled ester20 is formed by acetyl migration in11 to the ketene16 and subsequent addition of ethanol. In contrast, ethyl 2-benzoylpropionate is exclusively generated by migration of the methyl group in carbene13 since it contains the complete13C-labelling at the tertiary carbon atom (22).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00911927
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  • 4
    Electronic Resource
    Electronic Resource
    Die Photolyse von 2-Diazo-[1-13C]naphthalin-1(2H)-on und 1-Diazo-[1-13C]naphthalin-2(1H)-on1 Ein Beitrag zum Oxiren-Problem (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 3566-3573 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Photolysis of 2-Diazo-[1-13C]naphthalen-1(2H)-one and 1-Diazo-[1-13C]naphthalen-2(1H)-one. A Contribution to the Xoirene ProblemThe synthesis of 2-diazo-[1-13C]naphthalen-1(2H)-one (10) and 1-diazo-[1-13C]naphthalen-2(1H)-one (16) starting from Ba13CO3 is reported. The photolysis of 10 in dioxan/water (10: 1) leads to [carboxy-13C]indene-1-carboxylic acid (19). Correspondingly 16 yields [1-13C]indene-1-carboxylic acid (23). The absence of any isotope scrambling excludes an oxirene participation in the photolysis of 2- or 1-diazonaphthalen-1(2H)- or -2(1H)-one.
    Notes: Die Synthese von 2-Diazo[1-13C]naphthalin-1(2H)-on (10) und 1-Diazo-[1-13C]naphthalin-2(1H)-on (16) beginnend mit Ba13CO3 wird beschrieben. die Photolyse von 10 in Dioxan/Wasser (10: 1) führt zu [Carboxy-13C]Inden-1-carbonsäure (19). Entsprechend ergibt 16 [1-13C]Inden-1-carbonsäure (23). Das Ausbleiben einer Isotopenverteilung schließt eine Oxiren-Beteiligung bei der Photolyse von 2- bzw. 1-Diazonaphthalin-1(2H)- bzw. -2(1H)-on aus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751081118
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and Structure of a Bis(Double Helicate) and its Cryptatoclathrate“Adamantanoid Chelate Complexes”, Part 6; for Part 5, see ref. [4]. (1996)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 1363-1367 
    Details
    ISSN: 0947-6539
    Keywords: clathrates ; cryptates ; helicates ; selfassembly ; zinc complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structures of the hitherto unknown bis(double helicate) 10 and its cryptatoclathrate (10)2·2THF were unequivocally determined by X-ray diffraction. Bis(double helicate) 10 is formed in a one-pot synthesis starting from CH-acidic bis (tetrazolylmethyl ketone) 9 and Zn(OAc)2. The formation of racemic, homochiral 10 from [Zn2L32] fragments, which are formed in a self-assembly process, is governed by chiral self-recognition. According to NMR studies only 10 is present in solution. 13C CP/MAS NMR spectroscopy and X-ray analysis confirm aggregation of 10 with two molecules of THF to yield the inclusion compound (10)2·2 THF in the solid state.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19960021106
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  • 6
    Electronic Resource
    Electronic Resource
    Kohlenstoff-Markierungsstudien zur α-Oxocarben-Oxiren-Isomerisierung (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 678-688 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbon-Labelling Studies on the α-Oxocarbene-Oxirene IsomerizationThe photochemical Wolff rearrangement of α-diazoketones (1a - g, 3e - g), labelled with 13C or 12C, in dioxane/water yields carboxylic acids containing the label in the carboxy group and the adjacent carbon atom. This proves that the α-oxocarbenes, formed by photolytic elimination of nitrogen, undergo a carbene-carbene rearrangement via oxygen shift (4 ⇌ 5 ⇌ 6). in some cases to an extent of more than 60%, the degree depending upon the substituents and the irradiation wave-length.  -  For examination of the reaction model (scheme 1), both entry pathways (1 → 4, 3 → 6) to the carbene-oxirene-carbene equilibrium are realized by photolysis of the isomeric labelled α-diazoketones le, f, g / 3e, f, g. An alternative mechanism, whereby the scrambling of the carbon label takes place at the ketene stage, can be excluded.
    Notes: Die photochemische Wolff-Umlagerung der 13C- bzw. l2C-markierten α-Diazoketone (1a-g. 3e-g) in Dioxan/Wasser (13:2) führt zu Carbonsäuren, in denen die Markierung in die Carboxygruppe und das benachbarte Kohlenstoff-Atom eingeht. Dadurch wird belegt, Daß die durch photolytische N2-Eliminierung gebildeten α-Oxocarbene einer Carben-Carben-Umlagerung durch Sauerstoff-Verschiebung unterliegen (4 ⇌ 5 ⇌ 6), die je nach Substituenten und Wellenlänge des Lichtes mehr als 60% ausmachen kann.  -  Zur Untersuchung des Reaktionsmodells (Schema 1) werden beide Zugänge (1 → 4 und 3 → 6) zum Carben-Oxiren-Carben-Gleichgewicht durch Photolyse isomerer, markierter α-Diazoketone (1 e, f, g/3e, f, g) beschritten. Ein alternativer Mechanismus, der die Isotopenverteilung auf der Ketenstufe vorsieht. kann ausgeschlossen werden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120229
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  • 7
    Electronic Resource
    Electronic Resource
    Die Wolff-Umlagerung von α-Diazocarbonyl-Verbindungen (1975)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 87 (1975), S. 52-63 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die synthetisch leicht zugänglichen α-Diazocarbonyl-Verbindungen zeichnen sich durch eine hohe Reaktivität aus, die unter modifizierten Bedingungen eine Vielzahl von präparativen Möglichkeiten eröffnet. Bei der thermisch, photochemisch oder katalytisch induzierten Wolff-Umlagerung gehen die α-Diazocarbonyl-Verbindungen in Ketene über. Als Zwischenstufen oder Übergangszustände werden freie und komplexierte Carbene, 1,3-Dipole, 1,3-Diradikale und die antiaromatischen Oxirene diskutiert. Der vorliegende Fortschrittsbericht versucht, präparative und theoretische Aspekte zu integrieren.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19750870203
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  • 8
    Electronic Resource
    Electronic Resource
    Zur α-Oxocarben-Oxiren-Isomerisierung: Photolyse von [1-13C]-2-Diazo-1-phenyl-1-propanon und [2-13C]-1-Diazo-1-phenyl-2-propanonDiese Arbeit wurde von der Deutschen Forschungsgemeinschaft unterstützt. (1977)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 89 (1977), S. 827-828 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19770891120
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  • 9
    Electronic Resource
    Electronic Resource
    Photolyse von Naphth[2,3-d]-1,2,3-oxadiazol  -  Ein Beitrag zum Oxiren-Problem (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 551-555 
    Details
    ISSN: 0009-2940
    Keywords: Naphth[2,3-d]-1,2,3-oxadiazole ; 2,3-Naphthoquinone diazide ; Wolff rearrangement, photochemical ; Naphth[2,3-b]oxirene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photolysis of Naphth[2,3-d]-1,2,3-oxadiazole  -  A Contribution to the Oxirene ProblemThe photolysis of [9a-13C]naphth[2,3-d]-1,2,3-oxadiazole ([9a-13C]14) in methanol, water, and cyclohexane is studied. In the protic solvents, the Wolff rearrangement products 2-(methoxycarbonyl)indene ([13C=O]16) and 2-indenecarboxylic acid ([13C=O]23) exclusively labelled at the carbonyl carbon are obtained. Furthermore, the photolysis of [9a-13C]14 in methanol yields [2-13C]-2-naphthol (19) as hydrogen abstraction product. The photolytic decomposition of 14 in cyclohexane affords 2-(2-naphthoxycarbonyl)indene (25) and 1-cyclohexyl-2-(2-naphthoxycarbonyl)indene (26). The formation of 25 is explained by nucleophilic addition of 2-naphthol (19) to the intermediate ketene 21. 2-Naphthol (19) is generated in situ by hydrogen abstraction from cyclohexane. The cyclohexyl radicals, thereby obtained, convert 25 to 26. Similar photolysis of [9a-13C]14 affords [13C—O—13C=O]25 and [13C—O—13C=O]26 labelled at the carbonyl carbon and C-2 of the naphthalene ring. Thus, independent of the nature of the solvent (methanol, water, cyclohexane), no labelling distribution is found in the photolysis products of [9a-13C]14. This excludes the participation of naphth-[2,3-b]oxirene (17) as reactive intermediate.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270315
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  • 10
    Electronic Resource
    Electronic Resource
    Thermische Azulen-Umlagerungen. Synthese und Thermolyse von [6-13C]Azulen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2775-2784 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermal Azulene Rearrangements. Synthesis and Thermolysis of [6-13C]AzuleneA specific synthesis of [6-13C]azulene (24) is described. The synthetic sequence outlined in scheme 3 begins with the construction of [4-13C]toluene (17) which is performed in 8 steps starting from [13C]-paraformaldehyde. The suspected scrambling of the label in the dehydrogenation step 16 → 17 can be suppressed by suitable reaction conditions. After extension of the side chain by 3 carbon atoms to give 1-diazo-4-([4-13C]phenyl)-2-butanone (21), the labelled azulene is obtained according to Scott's azulene synthesis (21 → 22 → 23 → 24). The vacuum thermolysis of 24 (1050°C, 10-3-10-2 torr) yields [β-13C]naphthalene (25) as the main produkt (91% of the naphthalene formed) in accordance with the norcaradiene-vinylidene mechanism. The remaining 9% consist of [α-13C]naphthalene. Besides the formation of naphthalene (15% conversion), 24 suffers automerisation to a small extent yielding [5-13C]- and [1-13C]azulene (ca. 3 and 1%, respectively).
    Notes: Es wird eine gezielte Synthese von [6-13]Azulen (24) beschrieben. Die angegebene Synthesesequenz (Schema 3) erfordert zunächst den Aufbau von [4-13C]Toluol (17), der ausgehend von [13C]Paraformaldehyd in 8 Stufen erfolgt. Die auf der Dehydrierungsstufe 16 → 17 zu befürchtende Verteilung der 13C-Markierung im Benzolring kann durch geeignete Reaktionsbedingungen unterdrückt werden. Nach Verlängerung der Seitenkette um 3 Kohlenstoffatome zu 1-Diazo-4-([4-13C]phenyl)-2-butanon (21) wird entsprechend der Scottschen Azulensynthese (21 → 22 → 23 → 24) das markierte Azulen erhalten. Die Vakuumthermolyse von 24 (1050°C, 10-3-10-2 Torr) liefert in Übereinstimmung mit dem Norcaradien-Vinyliden-Mechanismus als Hauptprodukt [β-13C]Naphthalin (25) (91% des gebildeten Naphthalins). Die restlichen 9% entfallen auf [α-13C]Naphthalin. Neben der Naphthalin-Bildung (15% Umsatz) erleidet 24 in geringem Umfang eine Automerisierung zu [5-13C]- und [1-13C]Azulen (ca. 3 bzw. 1%).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160806
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