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  • 1
    Electronic Resource
    Electronic Resource
    Totalsynthese von Dinatrium-prephenat, I. Synthese von zwei diastereomeren 3-Ethoxy-1, 8-dioxo-2-oxaspiro[4.5]dec-6-en-3-carbonsäure-ethylestern (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1550-1570 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Total Synthesis of Disodium Prephenate, I. Synthesis of two Diastereomeric Ethyl 3-Ethoxy-1,8-dioxo-2-oxaspiro[4.5]dec-6-ene-3-carboxylatesThe synthesis of (3 SR, 5 SR)- and (3 RS, 5SR)-ethyl 3-ethoxy-1,8-dioxo-2-oxaspiro[4,5]dec-6-ene-3-carboxylates 18a and b, important key - step in the total synthesis of the disodium salt 1a of prephenic acid, is described. Both diastereomers were obtained starting with the isomeric keto dicarboxylic acids 4a,b via the ester lactones 14a,b, the hydroxy lactones 15a,b and the selenides 17a,b. The properties of all spirocyclic intermediates are discussed by means of their spectra.
    Notes: Die für die Totalsynthese des Dinatrium-Salzes 1a von Prephensäure als Zwischenstufen wichtigen beiden diastereomeren (3 SR,5SR)- und (3 RS,5SR)-3-Ethoxy-1,8-dioxo-2-oxaspiro[4.5]dec-6-en-3-carbonsäure-ethylester 18a und b wurden ausgehend von den isomeren α-Ketodicarbonsäuren 4a und b über die Lactonester 14a,b, die Hydroxylactonester 15a,b und die Selenide 17a,b synthetisiert. Die Eigenschaften aller spirocyclischen Zwischenstufen werden anhand ihrer Spektren diskutiert.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120507
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  • 2
    Electronic Resource
    Electronic Resource
    Darstellung von Cyclohexadienonen, III: Synthese und Eigenschaften von (Phenylseleno)cyclohexenonen und deren Überführung in Cyclohexadienone (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 1944-1957 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Cyclohexadienones, III: Synthesis and Properties of (Phenylseleno)cyclohexenones and their Transformation to CyclohexadienonesVarious 4,4-disubstituted 2-cyclohexen-1-ones (1) are transferred with benzeneselenenyl chloride to the corresponding 6-phenylseleno-2-cyclohexen-1-ones (3), which are characterized by spectral data. Reaction with hydrogen peroxide leads to 2,5-cyclohexadien-1-ones (5) with good yields.
    Notes: Verschiedenartig 4,4-disubstituierte 2-Cyclohexen-1-one (1) lassen sich mit Benzolselenylchlorid in die entsprechenden 6-Phenylseleno-2-cyclohexen-1-one (3) überführen, deren spektroskopische Eigenschaften beschrieben werden. Die Umsetzung mit Wasserstoffperoxid liefert in guten Ausbeuten die 2,5-Cyclohexadien-1-one (5).
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110528
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  • 3
    Electronic Resource
    Electronic Resource
    Totalsynthese von Dinatrium-prephenat, II. Synthese und sterische Zuordnung von Dinatrium-prephenat (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 1571-1584 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Total Synthesis of Disodium Prephenate, II. Synthesis and Stereochemical Assignment of Disodium PrephenateStarting with ethyl (3 SR,5SR), and (3RS, 5SR)-3-ethoxy-1,8-dioxo-2-oxaspiro[4.5] dec-6-ene-3-carboxylate (3a und b) disodium prephenate (1 a) and disodium epiprephenate (2) have been synthesized. The very unstable dienone 5 was obtained via the enone selenides 4a and b; it was reduced with 9-borabicyclo[3.3.1] nonane (9-BBN) to the dienols 10 a and b. The isomer 10a was transferred to disodium prephenate (1 a) Furthermore the dienols 10 a and b were hydrogenated and the NMR spectra of the saturated alcohols were compared with compounds of well-known stereochemistry. In this way, the configuration of prephenate 1 has now been established without doubt.
    Notes: Ausgehend von (3 SR,5SR), und (3RS, 5SR)-3-Ethoxy-1,8-dioxo-2-oxaspiro[4.5] dec-6-en-carbonsäure-ethylester (3a und b) konnten Dinatrium-prephenat (1a und Dinatrium-epiprephenat (2) synthetisiert werden. Über die diastereomeren Enonselenide 4a und b ließ sich das sehr labile Dienon 5 erhalten, das mit 9-Borabicyclo[3.3.1]nonan (9-BBN) zu den beiden Dienolen 10a und b reduziert wurde. 10a wurde in Dinatrium-prephenat (1a) übergeführt. Durch katalytische Hydrierung von 10a und b und anschließenden1H-NMR-Spektrenvergleich mit auf unabhängigem Wege synthetisierten Proben bekannter Konfiguration konnte die sterische Zuordnung von 1 spektroskopisch gesichert werden.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120508
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  • 4
    Electronic Resource
    Electronic Resource
    13C-NMR-Untersuchungen an 2-Cyclohexenonen und 2,5-Cyclohexadienonen (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 121-132 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 13C-NMR Investigations of 2-Cyclohexenones and 2,5-CyclohexadienonesProton noise decoupled 13C-NMR spectra of 26 2-cyclohexen-1-ones and 2,5-cyclohexadien-1-ones have been measured. The unequivocal assignment of the spectra was achieved with the aid of proton off-resonance decoupled spectra and by selective deuteration. Moreover, it became evident that assignments reported in the literature were wrong and need to be corrected. Effects of various substituents in position 4 of the system as well as solvent effects are discussed. The 13C-values of the carbonyl carbon of all cyclohexenones and cyclohexadienones proved to be of diagnostic value for both of these ring systems, often occurring in nature.
    Notes: Von 26 2-Cyclohexen-1-onen und 2,5-Cyclohexadien-1-onen wurden die 1H-breitbandentkoppelten 13C-NMR-Spektren aufgenommen. Die eindeutige Zuordnung der Signale erfolgte durch 1H-Off-Resonance-Entkopplung sowie durch selektive Deuterierung. Dabei zeigte sich, daß Zuordnungen in der Literatur falsch getroffen wurden und korrigiert werden müssen. Die Substituenteneinflüsse verschiedener sich in 4-Stellung befindlicher Reste sowie Lösungsmitteleffekte werden daneben diskutiert. Die13C-Resonanzen der Carbonylkohlenstoffatome von Cyclohexenonen und Cyclohexadienonen erwiesen sich als diagnostisch für jedes dieser beiden in der Natur häufig vorkommender Ringsysteme.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919790112
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  • 5
    Electronic Resource
    Electronic Resource
    2,5,7,7-Tetramethyloctanal und Derivate - eine neue Riechstoffklasse (1988)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 487-489 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,5,7,7-Tetramethyloctanal and Derivatives - a New Class of Odorants2,5,7,7-Tetramethyloctanal (3a) can be synthesized by heteroaldol reaction of 3,5,5-trimethylhexanal (1a) and propanal followed by partial hydrogenation. The odor of 3a is brighter than that of comparable known products like hydroxycitronellal. Insignificant variations of 3a, e.g. to the corresponding alcohol 4a and to its esters 4b and 4c causes dramatical changes of the odor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198819880521
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