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  • 1
    Electronic Resource
    Electronic Resource
    Terpenes and terpene derivatives, XXXIII. Synthesis of rac-cis- and -trans-dracunculifoliol and their 10-epimersDedicated to Manfred Schlosser on the occasion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 231-240 
    Details
    ISSN: 0947-3440
    Keywords: Dracunculifoliol ; Eudesmanes, 8(7→6)-abeo- ; Vassoura oil ; Baccharis dracunculifolia ; Terpenes ; Hydrindane Derivatives ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cis-aldehyde 9, a key intermediate in the total synthesis of cis-dracunculifoliol (1) previously isolated from Vassoura oil, was prepared starting from the bicyclic enone 5 via the nitrile 8. Grignard reaction of 9 led exclusively to epi-1. Oxidation to the ketone 10 followed by reduction gave a separable mixture of the natural isomer 1 and epi-1. - The synthesis of trans-dracunculifoliol (2) starts with the 6-methoxytetralone 14. After some usual steps, the trans-octalin 17 was obtained. MMPP-HIO4 oxidation gave compound 19 which was transformed into the iodo ester 26, precursor of the hydrindane ester 27. Analogously to the synthesis of epi-1 the epi-trans-dracunculifoliol (epi-2) was formed via alcohol 28 and aldehyde 29. Oxidation ( 30) and reduction furnished the natural trans alcohol 2. - Olfactory evaluation of the purified isomers 1, epi-1, 2, and epi-2 showed that all of them possess only a weak, woody odor. Therefore, the dracunculifoliols 1 and 2 are not responsible for the typical earthy, leathery, and spicy odor of the Vassoura oil.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950233
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  • 2
    Electronic Resource
    Electronic Resource
    On Some Italicene Derivatives (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 1641-1644 
    Details
    ISSN: 0947-3440
    Keywords: Tricyclic sesquiterpenes ; Italicene derivatives ; α-Copaene derivatives ; Essential oils ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidation of the tricyclic sesquiterpene hydrocarbon italicene (1a) or its 10-epimer 1b (isolated previously from Helichrysum oil) with SeO2 yielded mixtures of italicene-5-one (3a), italicen-15-al (4a), italicen-5-ol (9a) and italicen-15-ol (10a) or their 10-epimers 3b, 4b, 9b, 10b, whereas commercial α-copaene (6) reacted only to give a mixture of α-copaen-15-al (7) and α-copaen-15-ol (8). Jones oxidation of the allyl alcohols 9a or 9b afforded the pure ketones 3a or 3b MnO2 oxidation of the alcohols 10a or 10b furnished the aldehydes 4a or 4b. - Surprisingly, the italicene epoxides 2a or 2b rearranged with diluted HCl to the italicene ethers (epoxyacorenes) 5a or 5b, which previously were isolated from Lantana and Helichrysum oil. - The odor of 3a, 3b, 4a, 4b and 5a was evaluated.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961022
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  • 3
    Electronic Resource
    Electronic Resource
    New cis-Eudesm-6-ene Derivatives from Vetiver OilDedicated to Professor Ekkehard Winterfeldt on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1783-1787 
    Details
    ISSN: 0947-3440
    Keywords: cis-Eudesm-6-ene derivatives ; Vetiver oil ; Essential oils ; Odoriferous substances ; Sesquiterpenes ; Natural products ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new cis-eudesma-6,11-diene (1) has been isolated from vetiver oil as a main constituent of the sesquiterpene hydrocarbon fraction. Furthermore, six derivatives [13-nor-cis-eudesm-6-en-11-one (2), cis-eudesm-6-en-11-ol (4), cis-eudesm-6-en-12-al (5, 2 epimers), 13-nor-cis-eudesm-6-en-8-one (6), and cis-eudesma-6,11-dien-3-ol (8)] have been identified in the oil. Three of these (2, 4, 5) have been prepared for comparison purposes, e.g. via ozonolysis or hydroboration starting from 1.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970823
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  • 4
    Electronic Resource
    Electronic Resource
    Fragmentierungsreaktionen and Carbonylverbindungen mit β-ständigen elektronegativen Substituenten, XXV. 5,5-Dimethyl-6-tosyloxy-3-hexen-2-on, ein vinyloges β-Tosyloxyketon (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 887-891 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentation Reactions of Carbonyl Compounds with electronegative Substituents in the β-Position, XXV. 5,5-Dimethyl-6-tosyloxy-3-hexen-2-one, a Vinylogous β-TosyloxyketoneThe α,β-unsaturated tosyloxyketone 2c is synthesized by Horner-Wittig reaction of 4 from the tosyloxyaldehyde 1c or via the tetrahydropyranyl ether 1b. 2c gives with KOH in methanol depending on reaction time the cyclohexenone 5 or the cyclobutyl ketone 6a. With KCN in DMSO 2c reacts to yield a mixture of dihydropyrane 7 and cyanocyclobutane 6b.
    Notes: Das α,β-ungesättigte Tosyloxyketon 2c wird durch Horner-Wittig-Reaktion aus dem Tosyloxyaldehyd 1c mit 4, bzw. über den Tetrahydropyranyläther 1b, dargestellt. Aus 2c, erhält man mit KOH in Methanol in Abhängigkeit von der Reaktionszeit das Cyclohexenon 5 bzw. das Cyclobutylketon 6a. Mit KCN in DMSO reagiert 2c zu einem Gemisch aus dem Dihydropyran 7 und dem Cyancyclobutan 6b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070315
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  • 5
    Electronic Resource
    Electronic Resource
    Fragmentierungsreaktionen an Carbonylverbindungen mit β-ständigen elektronegativen Substituenten, XXX. Solvolyse von 2,2-Bis(tosyloxymethyl)cycloalkanonen (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 3448-3460 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentation Reactions of Carbonyl Compounds with Electronegative Substituents in the β-Position, XXXThe alkaline solvolysis of the enolizable ditosylates 11, 22-24, 26, 27 preferably leads to the methylenecycloalkane carboxylic acids 30, 31, 6b, 32-34. From 11, 22, and 24, the open-chain ω-methylenecarboxylic acids 37-39 are obtained, too. Furthermore, in the case of cyclohexanone ditosylates (22-24) multiple rearrangement leads to cyclopentenylpropionic acids (35, 5b, 36). - The non-enolizable ditosylate 25 gives Michael addition products (41, 42) of the intermediate 2-methylenecyclohexanone 48, on the other hand 48 reacts with itself to give the Diels-Alder product 47b. - Thus it is proved that the ditosylate 2 is an intermediate in the solvolysis of the tetratosylate 1.
    Notes: Die enolisierbaren Ditosylate 11, 22-24, 26, 27 liefern bei der alkalischen Solvolyse überwiegend die Methylencycloalkancarbonsäuren 30, 31, 6b, 32-34. Aus 11, 22 und 24 werden daneben auch die offenkettigen ω-Methylencarbonsäuren 37-39 erhalten. Mehrfache Umlagerung führt bei Cyclohexanon-ditosylaten (22-24) außerdem zu Cyclopentenylpropionsäuren (35, 5b, 36). - Das nicht enolisierbare Ditosylat 25 liefert einerseits Michael-Additionsprodukte (41, 42) des intermediären 2-Methylencyclohexanons 48, andererseits dessen Diels-Alder-Produkt 47b. - Damit wird bewiesen, daß das Ditosylat 2 ein Zwischenprodukt bei der Solvolyse des Tetratosylats 1 ist.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751081104
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  • 6
    Electronic Resource
    Electronic Resource
    Zur Bildung, Trennung und Zuordnung diastereomerer CCl2-Bis-Addukte an Diolefine (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1564-1575 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation, Separation, and Assignment of Diastereomeric CCl2-Bisadducts to DiolefinsMeso- and d,l-forms of CCl2-bisadducts to diolefins 1-7 and 9 are separated and mostly assigned. Partial resolution of 1b-enantiomers as well as dipole moments and high resolution 1H n.m.r. spectra provide structural assignment. Tricyclic bisadducts 12 and 14 are obtained exclusively anti, 16, however, syn.
    Notes: Die meso- und d,l-Diastereomeren der CCl2-Bis-Addukte an Diolefine 1-7 und 9 werden getrennt und weitgehend zugeordnet. Partielle Enantiomerentrennung von 1b beweist die Zuordnung, die jedoch auch durch Messung der Dipolmomente und durch hochaufgelöste 1H-NMR-Spektren getroffen werden kann. Die tricyclischen Bis-Addukte 12 und 14 entstehen ausschließlich in der anti-. 16 dagegen in der syn-Form.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100439
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  • 7
    Electronic Resource
    Electronic Resource
    Fragmentierungsreaktionen an Carbonylverbindungen mit β-ständigen elektronegativen Substituenten, XXII. cis- und trans-4.4.8.8-Tetramethyl-2.6-dioxa-bicyclo[3.3.0]octan aus 1.6-Bis-p-toluolsulfonyloxy-2.2.5.5-tetramethyl-hexandion-(3.4) (1972)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 3553-3565 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentation Reactions of Carbonyl Compounds with Electronegative β-Substituents, XXII. cis- and trans-4.4.8.8-Tetramethyl-2.6-dioxabicyclo[3.3.0]octane from 1.6-Bis(tosyloxy)-2.2.5.5-tetramethyl-3.4-hexanedioneTreatment of 1.6-bis(tosyloxy)-2.2.5.5-tetramethyl-3.4-hexanedione (5) with NaBH4, NaOH/CH3OH and CH3MgJ leads to 2.6-dioxabicyclo[3.3.0]octanes c-7, t-7, 8, and 10. In addition the tetrahydrofuran derivatives 12, 13, and E-18 are isolated, which are considered to be intermediates. 12 and E-18 can be converted to 8 and t-7 respectively by NaOH/CH3OH. The hitherto unknown trans-2.6-dioxabicyclo[3.3.0]octane skeleton is proved. The mechanistic intermediates 11 and E-18 are prepared independently by NaBH4-reduction of monotosylate 4 to 6 and E-17, followed by tosylation. Treatment of 11 with NaBH4 affords a mixture of c/t-7 and E-18 having the same composition as that obtained from 5. Reduction of 12 gives 9.
    Notes: Die Umsetzung von 1.6-Bis-tosyloxy-2.2.5.5-tetramethyl-hexandion-(3.4) (5) mit NaBH4, NaOH/CH3OH und CH3MgJ führt zu den 2.6-Dioxa-bicyclo[3.3.0]octanen c-7, t-7, 8 und 10. Daneben werden jeweils die Tetrahydrofuran-Derivate 12, 13 und E-18 isoliert, die als Zwischenstufen anzusehen sind. 12 und E-18 können separat wiederum mit NaOH/CH3OH zu 8 bzw. t-7 umgesetzt werden. Das bisher nicht bekannte trans-2.6-Dioxa-bicyclo[3.3.0]octan-Gerüst ist bewiesen. Die vom Mechanismus postulierten Zwischenstufen 11 und E-18 werden unabhängig durch NaBH4-Reduktion des Monotosylats 4 zu 6 und E-17 und anschließende Tosylierung erhalten. Aus 11 wird mit NaBH4 ein Gemisch aus c/t-7 und E-18 gleicher Zusammensetzung wie aus 5 erhalten. NaBH4-Reduktion von 12 führt zu 9.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19721051108
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  • 8
    Electronic Resource
    Electronic Resource
    Fragmentierungsreaktionen an Carbonylverbindungen mit β-ständigen elektronegativen Substituenten, XXIII. cis- und trans-4.4.8.8-Tetraalkyl-2.6-dioxa-bicyclo[3.3.0]octane aus 1.6-Bis-p-toluolsulfonyloxy-2.2.5 5-tetraalkyl-hexandionen-(3.4) (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 91-104 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentation Reactions of Carbonyl Compounds with Electronegative ß-Substituents, XXIII cis- and trans-4.4.8.8-Tetraalkyl-2.6-dioxabicyclo[3.3.0]octanes from 1.6-Bis(tosyloxy)-2.2.5.5-tetraalkyl-3.hexandionesDiketoditosylates 8 and 9a-c are prepared and reduced with NaBH4. 8 yields 16a and a cis-trans mixture of 23; 9a-c afford the tetrahydrofuranols 14a-c and the cis-2.6-dioxabicyclo[3.3.0]octanes 21a-c. 14a-c and 16a react with NaOH in methanol to form the pure trans-compounds 21a-c and 23. Solvolysis of 9a with excess NaOH in methanol leads to the tetrahydrofuranone 13a and to the bicyclo acetal 22a. Solvolysis of 9b with only 2 equivalents of NaOH yields thc intermediate 12, which can be isolated and converted to 13b and 22b.The trispiro compound 27 is isolated as an unexpected side product from the NaBH4-reduction of 9b.
    Notes: Die Diketo-ditosylate 8 und 9a-c werden dargestellt und mit NaBH4 reduziert. 8 liefert 16a und ein cis-trans-23-Gemisch, aus 9a-c werden die Tetrahydrofuranole 14a-c und die cis-2.6-Dioxa-bicyclo[3.3.0]octane 21a-c erhalten. 14a-c und 16a reagieren mit NaOH in Methanol zu den reinen trans-Verbindungen 21a-c und 23. Die Solvolyse von 9a mit überschüssigem NaOH in Methanol führt zu dem Tetrahydrofuranon 13a und dem bicyclischen Acetal 22a. Mit 2 Äquivv. NaOH kann aus 9b die Zwischenstufe 12 isoliert und erneut zu 13b und 22b umgesetzt werden.Als ungewöhnliches Nebenprodukt tritt bei der NaBH4-Reduktion von 9b die Trispiroverbindung 27 auf.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731060113
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  • 9
    Electronic Resource
    Electronic Resource
    Fragmentierungsreaktionen an Carbonylverbindungen mit β-ständigen elektronegativen Substituenten, XXIX. 2,2,5,5-Tetrakis(tosyloxymethyl)cyclopentanon und 2,2,6,6-Tetrakis(tosyloxymethyl)cyclohexanon (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 3433-3447 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentation Reactions of Carbonyl Compounds with Electronegative Substituents in the β-Position, XXIXAlkoxides react with the tetratosylate 10 to give a mixture of olefinic carboxylic acids or esters 11, 16, 18, 20. Main products are the dienoic acid 16 or their subsequent product 18. Applying the same conditions to the tetratosylate 14 only the acids 17, 19 and 21, homologues of 16, 18, and 20, were isolated. Less reaction time leads to an intermediate ditosylate 24a. This reacts with sodium methoxide to give the spiro acetal 28. After heating of 28 the enol ether 22a was isolated.
    Notes: Bei der Umsetzung des Tetratosylats 10 mit Alkoholaten erhält man ein Gemisch aus den Olefincarbonsäuren bzw. -estern 11, 16, 18, 20. Hauptprodukte sind die Diencarbonsäure 16 bzw. deren Folgeprodukt 18. Unter gleichen Bedingungen werden aus dem Tetratosylat 14 nur die zu 16, 18 und 20 homologen Säuren 17, 19 und 21 isoliert. Nach kürzerer Reaktionszeit konnte als Zwischenprodukt ein Ditosylat 24a isoliert werden. Dieses reagiert mit Natriummethylat zum Spiroacetal 28, das beim Erhitzen den Enoläther 22a liefert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19751081103
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  • 10
    Electronic Resource
    Electronic Resource
    Fragmentierungsreaktionen an Carbonylverbindungen mit β-ständigen elektro-negativen Substituenten, IV.III. Mitteil.: J. Jančulev, F. Nerdel, D. Frank und G. Barth, Chem. Ber. 99, 715 (1966), vorstehend. Hepten-(6)-säuren und Bicyclo[3.1.1]- bzw. -[3.2.0]heptanone-(6) (1967)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 720-735 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Umsetzung alkylsubstituierter Cyclohexanone, 1a-1i, die in β-Stellung zur Carbonyl-gruppe Substituenten wie OTs, Halogen oder ⊕N(CH3)3 tragen, mit wäßrig-alkoholischer Natronlauge liefert neben den durch Fragmentierung entstehenden Hepten-(6)-säuren als Haupt-produkte Bicyclo[3.1.1]- und -[3.2.0]heptanone-(6). Die NMR-Spektren der bicyclischen Ketone gestatten die Zuordnung zur [3.1.1]- oder [3.2.0]-Reihe.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19671000305
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