ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Organic Chemistry  (24)
  • Cell & Developmental Biology  (4)
  • 1975-1979  (28)
  • 1976  (28)
  • 1
    Electronic Resource
    Electronic Resource
    A Chemical Investigation of the Volatile Constituents of East Indian Sandalwood Oil (SantalumalbumL.) (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 737-747 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Distillation foreruns from East Indian sandalwood oil (Santalum album L.), representing 5-8% of the oil, have been investigated using fractional distillation, preparative column chromatography, gas liquid chromatography (GLC.), and chemical treatments. This allowed the isolation and characterization by their spectral data of 46 compounds. 32 of them were newly identified sandalwood oil constituents including 4 novel substances: santalone (2), 4-methylcyclohexa-1,3-dien-1-yl methyl ketone (4), 5,6-dimethyl-5-norbornen-exo-2-ol (7), and (E)-5-(2,3-dimethyl-3-nortricyclyl)-pent-3-en-2-one (20). The other constituents identified were 1-furfuryl-pyrrole (10) and 10 phenols accompanied by 17 terpene and sesquiterpene derivatives. Endo-2,endo-3-dimethyl-norbornan-exo-2-ol (6), an α-santenol (z), precursor, was present in the last group of constituents. The compounds 2, 4, 6, 7, 20 have been synthesized as well as another novel constituent, endo-2-mythyl-3-methylidene-norbornan-exo-2-ol (5).
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Zum Mechanismus der photochemischen Umwandlung von 2-Alkyl-indazolen in 1-Alkyl-benzimidazole. I. Struktur und Reaktivität eines Zwischenproduktes (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 1512-1527 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mechanistic studies on the photoisomerization of 2-alkyl-indazoles into 1-alkyl-benzimidazoles. I. Structure and reactivity of an intermediate.2-Alkyl-indazoles (1) undergo photochemical isomerization to 1-alkyl-benzimidazole via previously unknown intermediates 3 (Scheme 1). In the present paper the structure and reactivity of these intermediates are discussed. Low-temperature irradiation (-60°) of 1 b with 300 nm light gives 3 b in quantitative yield. 3 b is transformed during warm-up to 1 b and 2 b (UV.-evidence). The formations of 1 and 2 show the same temperature dependence but their ratio is found to be temperature-independent. In contrast to the above behaviour, low-temperature irradiation with 250 nm light of 3 b yields 1 b only (no 2 b). These findings are consistent with the proposed reaction mechanism 2 c in Scheme 2.On the basis of spectroscopic properties and the described reaction pathways, it appears that the most suitable structure for intermediate 3 is a 7,8-diaza-tricyclo[4.3.0.07,9]nona-2,4,6(10)-trien (9). In Scheme 4 the reaction pathway for the iudazole-benzimidazole-rearrangement is summarized.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590512
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Conformational Analysis and Chromic Acid Oxidation. Oxidation Rates and Equilibrium Constants of Epimeric Alcohols (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 2335-2343 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The linear free energy relationship of Sicher for relative reactivity towards chromic acid oxidation (ΔΔGOx≠) as a function of thermodynamic stability (ΔGeq0) has been reexamined with 23 pairs of epimeric alcohols. The plot of ΔGOx≠ vs. ΔGeq0 has a slope of 0.8, a correlation coefficient of 0.97 and a standard deviation of 0.23 kcal/mol on ΔΔGOxOx≠. The limitations of the relationship and the exceptions are discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590706
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Zum Mechanismus der Photochemie von 2-Alkylindazolen in wässerigen Lösungen (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 2362-2373 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mechanistic studies on the photochemistry of 2-alkylindazoles in aqueous solutions.The photochemistry of 2-alkylindazoles 1 in aqueous solutions is rather complex, the relative yields of different products being dependent on the pH-value of the irradiated solution: In neutral or basic solutions (pH 〉 7) as well as in most of the organic solvents isomerization to 1-alkyl-benzimidazoles 2 takes place. In dilute sulfuric acid (pH 2-4) this reaction is suppressed and the dihydro-azepinones 3 and 4 are formed. Irradiation in strongly acid solutions (pH 〈 1) yields the o-amino-acetophenones 5 (Scheme 1).The relative quantum yields of the photoproducts 2-5 have been measured as a function of the pH-value of the irradiated solution (Fig. 1). A comparison of these yields with the protonation equilibrium of the indazole in its first excited singlet state (pK = 2.8) suggests that 2 and 3 are both photoproducts of the neutral indazole molecule, whereas 4 as well as 5 are formed from the protonated indazole.The rearrangement of the indazole 1 to the benzimidazole 2 proceeds via an intermediate 6, which can be produced in high concentrations by monochromatic irradiation of 1 at low temperatures. The thermal reactivity of this intermediate in dilute sulfuric acid could be investigated: At pH 8 the only product is the benzimidazole 2. With decreasing pH-value increasing amounts of 3 are formed and at pH 〈 4 the formation of 2 is completely suppressed, the only product being the azepinone 3. Thus, 3 is a solvolysis product of the intermediate 6 (Scheme 2).The most probable primary product of singlet indazolium is the nitrenium ion 7. From this intermediate the formation of 5 can proceed in well-known thermal reactions. The formation of 4 is possibly due to a further protonation equilibrium nitrenium-nitrene. The nitrene 7 can be converted into the azepinone 4 via the azirine 8 (Scheme 3). The pK-values of different indazoles and intermediates are listed in the Table.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590709
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Homoisoflavanone. IV.Teil III: siehe [1]. Neue Inhaltsstoffe der Eucomin-Reihe von Eucomis bicolor (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 2048-2058 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homoisoflavanones. IV. New constituents of the Eucomin Series of Eucomis bicolor.Four new homoisoflavanones, (E)-7-O-methyl-eucomin (2a), ( - )-7-O-methyleucomol (5), (+)-3,9-dihydro-eucomin (7a) and 7-O-methyl-3,9-dihydro-eucomin (8), were isolated from the bulbs of Eucomis bicolor Bak. (Liliaceae). Their structures were determined by spectral data and synthesis. These compounds occur exclusively in the waxy material between the bulb leaves. Furthermore it was shown that only (Z)-eucomin (1b) is genuine, (E)-eucomin (1a) being an artefact. It is likely that 2a is also not genuine. A new method for a selective 7-O-methylation is described.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590618
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Synthese deuteriierter Derivate diastereomerer Cyclopentapeptide für die KonformationsanalyseWir danken dem Schweizerischen Nationalfonds zur Förderung der Wissenschaftlichen Forschung für finanzielle Unterstützung dieser Arbeit. Nomenklatur und Abkürzungen entsprechen den in der Peptid- und Proteinchemie üblichen Normen, vgl. E. Wünsch, «Synthese von Peptiden», Bd. 15, Houben-Weyl, «Methoden der organischen Chemie», E. Müller, Herausgeber, Georg Thieme Verlag, Stuttgart 1974. (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 2196-2200 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Deuteriated Derivatives of Diastereomeric Cyclopentapeptides for Use in Conformational Analysis.The syntheses and properties of eight cyclic pentapeptides containing glycine with two deuterium atoms at C(α) (Gly*) are described: cyclo-[-Gly-L-Cys(DPM)-Gly-Gly*-L-Pro-], cyclo-[-Gly*-L-Cys(DPM)-Gly-Gly*-L-Pro-], cyclo-[-Gly-L-Cys-(DPM)-Gly-Gly*-D-Pro-], cyclo-[-Gly*-L-Cys(DPM)-Gly-Gly*-D-Pro-], cyclo-[-Gly-L-Ala-Gly-Gly*-L-Pro-], cyclo-[-Gly*-L-Ala-Gly-Gly*-L-Pro-], cyclo-[-Gly-L-Ala-Gly-Gly*-D-Pro-], and cyclo-[-Gly*-L-Ala-Gly-Gly*-D-Pro-] (DPM = diphenylmethyl). These particular compounds were chosen in order to assign by NMR. unambiguously certain conformational features, like hydrogen-bonding and shielding, to individual peptide bonds.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590632
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Photochemistry of Tricyclo[3.3.1.02,7]nonan-6-ones. Preliminary communication (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 2902-2905 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sensitized irradiation (λ = 254 nm) of the title compounds 2 a and 2 b in benzene affords the tetracyclic oxetanes 3 a and 3 b. The irradiation of 2 c under similar conditions yields equal amounts of 3 c and the cyclopentadiene derivative 5. The formation of the photoproducts is discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590827
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Photochemistry of 4,4-Dialkoxy-2,5-cyclohexadienones (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 661-664 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Irradiation (λ 〉 370 nm) of 4,4-dimethoxy-2,5-cyclohexadienone (1 a) in benzene affords mainly the ketene acetal 4 a, which then undergoes further rearrangement. The carbomethoxycyclopentenones 6 and 7 were isolated in modest yields (10-15°). It is conceivable that the latter results from decomposition of the unobserved bicyclohexenone 5 a, the formation of which could be expected by analogy to e.g. 1 c → 5 c. Compound 4 a is presumably formed via 1,2 hydrogen shift from the intermediate zwitterion 3 a. Under similar irradiation conditions 1,4-dioxa-spiro[4.5] deca-6,9-dien-8-one (1 b) gave 4 b as the only definable product. In i-C8H18 1 a gave p-methoxyphenol (8) as the only product, most probably via hydrogen abstraction.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590232
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Preparation and Antimicrobial Activity of enantio-[1-Valine]malformin (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 1127-1132 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die stufenweise Synthese der im Titel genannten Verbindung, , wird beschrieben. Die mikrobiologische Untersuchung dieser Verbindung zeigt, dass sie das Wachstum von Gram-negativen Mikroorganismen nicht beeinflusst.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590416
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    A 13C- and 15N-NMR. Study of Some 1-Aryl-3, 3-dimethyl Triazene Derivatives (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 1655-1660 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C- and 15N-NMR. spectra have been measured for a series of triazenes. The results are compatible with the significant contribution of a structure such as II. One-bond nitrogen-nitrogen coupling constants are reported.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590526
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...