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  • 1
    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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  • 2
    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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  • 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
    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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  • 5
    Electronic Resource
    Electronic Resource
    Zum Mechanismus der Wolff-Umlagerung (1972)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 1875-1886 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Mechanism of the Wolff RearrangementThe thermal and electron impact induced Wolff rearrangement of [carbonyl-13C]azibenzil (6) occurs without migration of the labelling. In contrast in the photochemically performed reaction a part of the label is found in the tertiary carbon atom of the resulting diphenylacetic acid, which proves the formation of an oxirene intermediate. The amount of the oxirene is smaller when the water concentration is increased. The participation of the oxirene intermediate is discussed on the basis of two alternative reaction mechanisms.
    Notes: Bei der thermischen und elektronenstoß-induzierten Wolff-Umlagerung von [Carbonyl-13C]-Azibenzil (6) bleibt die Markierung in der Carbonylgruppe fixiert. Im Gegensatz dazu gelangt im photochemischen Fall ein Teil der Markierung in das tertiäre C-Atom der resultierenden Diphenylessigsäure, wodurch der Weg über ein Oxiren bewiesen wird. Dieser Anteil nimmt bei höherer Wasserkonzentration ab. Das Auftreten der symmetrischen Oxiren-Zwischenstufe wird an Hand von zwei alternativen Reaktionsmechanismen diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19721050610
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  • 6
    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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  • 7
    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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  • 8
    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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  • 9
    Electronic Resource
    Electronic Resource
    Über die Bildung von Oxirenen aus cyclischen α-Diazoketonen (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 1549-1557 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Formation of Oxirenes from Cyclic α-DiazoketonesThe reactions following the nitrogen elimination from 2-diazo-12-methyl-1-cyclododecanone (15) are studied. In the intermediate 12-membered α-oxocarbene 17 the first example of a photochemically and thermally induced 1,2-shift of oxygen in a cyclic α-oxocarbene is described. The rearrangement involves the condensed oxirene system 18. The occurrence of the two isomeric α-oxocarbenes 17 and 17′ is demonstrated by the subsequent 1,2-hydrogen rearrangement to isomeric α,β-unsaturated ketones (19, 20 and 19′, 20′). In contrast no oxirene participation is found in the silver oxide-catalysed reaction.
    Notes: Die Folgereaktionen nach der Stickstoff-Abspaltung aus 2-Diazo-12-methyl-1-cyclododecanon (15) werden untersucht. Am intermediären 12-Ring-α-oxocarben 17 wird das erste Beispiel einer photochemisch und thermisch ausgelösten 1,2-Sauerstoffverschiebung in cyclischen α-Oxocarbenen beschrieben. Die Umlagerung verläuft über das kondensierte Oxiren-System 18. Das Auftreten der beiden isomeren α-Oxocarbene 17 und 17′ wird durch die nachfolgende 1,2-Wasserstoff-verschiebung zu isomeren α,β-ungesättigten Ketonen (19, 20 und 19′, 20′) belegt. Im Gegensatz dazu wird bei der silberoxid-katalysierten Reaktion keine Oxiren-Beteiligung gefunden.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110436
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  • 10
    Electronic Resource
    Electronic Resource
    Zur α-Oxocarben-Oxiren-Isomerisierung; Photolyse von [1-12C]-1-Diazo-2-propanon und [1-13C]-2-Diazopropanal (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 2036-2042 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Oxocarbene-Oxirene Isomerization; Photolysis of [1-12C]-1-Diazo-2-propanone and [1-13C]-2-DiazopropanalThe mutual interconversion of acetylcarbene (10) and formyl(methyl)carbene (12) via methyloxirene (11) is investigated by photochemical nitrogen elimination from [1-12C]-1-diazo-2-propanone (8) and [1-13C]-2-diazopropanal (9). As concluded from the labelling distribution in the photolysis products of 8 and 9, the Wolff rearrangement proceeds in both cases predominantly from formyl-(methyl)carbene (12).
    Notes: Mit Hilfe der photochemischen Stickstoff-Abspaltung aus [1-12C]-1-Diazo-2-propanon (8) und [1-13C]-2-Diazopropanal (9) wird die wechselseitige Umwandlung von Acetylcarben (10) und Formyl(methyl)carben (12) über Methyloxiren (11) untersucht. Aus der Markierungsverteilung in den Photolyseprodukten von 8 und 9 folgt, daß in beiden Fällen die Wolff-Umlagerung überwiegend vom Formyl(methyl)carben (12) ausgeht.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919791214
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