ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-(2′-Deoxy-2′-fluororibofuranosyl)pyrimidines were synthesized and incorporated into an RNA oligonucleotide to give 5′-r[CfGCf(UfUfCfG)GCfG]-3′ (Cf: short form of Cd2′f2′ = 2′-deoxy-2′-fluorocytidine; Uf: short form of Ud2′f2′ = 2′-deoxy-2′-fluorouridine). The oligomer was investigated by means of UV, CD, and NMR spectroscopy to address the question of how F-labels can substitute 13C-labels in the ribose ring. Through-space (NOE) and through-bond (scalar couplings) experiments were performed that make use of the ameliorated chemical-shift dispersion induced by 19F as an alternative heteronucleus. A comparison of the structures of fluorinated vs. unmodified oligomer is given. It turns out that the fluorinated oligonucleotide exists in a 14:3 equilibrium between a hairpin and a duplex conformation, in contrast to the unmodified oligonucleotide which predominantly adopts the hairpin conformation. Furthermore, the fluorinated hairpin structure adopts two distinct conformations that differ in the sugar conformation of the Uf5 and Cf6 nucleoside units, as detected by the 19F-NMR chemical shifts. The role of the 2′-OH group as stabilizing element in RNA secondary structure is discussed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 608 (1957), S. 43-53 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Ozonisierung von Cholesterin(acetat) in alkoholfreien Lösungsmitteln werden nur in geringer Menge kristallisierte Produkte erhalten. In alkoholhaltigen Lösungsmitteln entstehen kristallisierte Verbindungen, wobei 1 Mol. Ozon und 1 Mol. Alkohol (Methanol, Äthanol, Isoamylalkohol) aufgenommen werden. Durch Reduktion mit Lithiumalanat werden sie in ein Triol, das 5.6-Seco-koprostan-3β.5.6-triol, übergeführt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 615 (1958), S. 222-227 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrierung des 5.6-Seco-5.6-peroxydo-3β-acetoxy-5-hydroxy-6-äthoxy-cholestans (oder -koprostans) führt über ein unbeständiges Halbacetal zum 5.6-Seco-3β-acetoxy-cholestan-5-on-6-aldehyd, der durch weitere Hydrierung in 5.6-Seco-3β-acetoxy-cholestan-5-on-6-ol und 5.6-Seco-koprostan-3β.5.6-triol übergeht. Aus dem Phenylhydrazon des Aldehyds werden durch Hydrierung Derivate des 5.6-Seco-cholestans (oder -koprostans) erhalten, die an C-6 eine (substituierte) Aminogruppe tragen.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 385 (1911), S. 328-340 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Generation of N,N-Disubstituted Iminium Salts by Application of Silane Reagents(Dialkylamino)trimethylsilanes, halotrimethylsilanes and trimethylsilyl triflate proved to be superior reagents for a convenient access to the title compounds in an aprotic medium. In most cases, the co-formation of silylethers or disiloxanes acts as driving force. A comprehensive overview on this field, including the latest findings, is given and the significant mechanistic relationships are illuminated. The three component synthesis starting from carbonyl compounds (Scheme 3) and the two component synthesis (“latent” three component synthesis) starting from α-chloroethers (Schemes 16, 19) hold a central position. The latter method offers special advantage for the entrance into the multifunctional series, as shown by the first synthesis of vinylogous Viehe salts as preparatively useful C3-building blocks (Schemes 17, 22, 23). As an aim, this report should stimulate further progress in these areas.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0947-3440
    Keywords: Antibiotics ; Soraphen ; Macrolide antibiotics ; Structure-activity relationship ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The partial synthesis of 11 analogues of soraphen A1α (1) is described. Reductive lactone ring cleavage, transformation into (17R,S)-soraphenic acid 10 and cyclization provided unnatural 17-epi-soraphen A1α (12). Removal of the phenyl-C-17 ring segment of 1 by cleavage of the lactone moiety and the C-16/C-17 bond gave the aldehyde 16 as central intermediate. After homologation of 16, introduction of a new C-17 substituent R or H, and cyclization of the lactone ring, the soraphen analogues butyl-, thienyl-, and tolylsoraphen 2b, d, e and 22b, d, e and the desphenylsoraphen 2a were obtained. The ring-contracted soraphen analogues norsoraphen 29 and 30 and desphenylnorsoraphen 31 were synthesized by introduction of a phenyl group or reduction of the intermediate aldehyde 23 followed by cyclization to the lactone. The biological activity of the soraphen analogues against Candida albicans was determined. Compared to the natural product, all analogues exhibit reduced activity. The activity of the analogues strongly depends upon the nature of the substituent R, the configuration at C-17, and the ring size.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 5 (1922), S. 640-644 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 13 (1961), S. 188-196 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Allyläther des 4,4′-Dioxydiphenyl-propan-2,2 lassen sich auf mit Formamid vorbehandeltem Papier mit Gemischen von Benzin und Chloroform als Fließmittel chromatographieren und mit diazotiertem Benzidin bzw. Kaliumpermanganat nachweisen.Dieses Verfahren ermöglicht eine laufende Kontrolle des Reaktionsverlaufs bei der präparativen Darstellung des 4,4′-Dioxydiphenyl-propan-mono- und -diallyläthers sowie eine schnelle und exakte Untersuchung des Reinheitsgrades der Reaktionsprodukte.Ferner stellt das von uns ausgearbeitete Verfahren eine neue Methode zur Untersuchung der CLAISEN-Umlagerung dar. Es konnte damit festgestellt werden, daß diese Umlagerung beim Diallyläther des 4,4′-Dioxydiphenyl-propan-2,2 bereits bei 130 °C beginnt.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 11 (1960), S. 11-19 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Epoxydverbindungen werden durch Umsetzung mit Phenolsulfonsäuren, Pikrinsäure, Pikramid und N-Methylpikramid in Dioxan in Derivate überführt. Es bilden sich durch Öffnung des Epoxydrings in 1- bzw. 2-Stellung jeweils zwei stellungsisomere Derivate. Für die Papierchromatographie eignen sich insbesondere die durch Umsetzung mit Pikrinsäure in Dioxan in der Siedehitze erhaltenen Derivate. Ihr papierchromatographisches Verhalten wurde näher untersucht. Sie werden auf formamidimprägniertem Papier mit Mischungen von Zyklohexan-Toluol (insbesondere 2:1) chromatographiert. Da die Farbe der Derivate pH-abhängig ist, ist für jede Verbindung zunächst nur ein orangefarbiger Fleck sichtbar. Erst bei höherem pH-Wert (Behandeln mit Ammoniak-Dampf) wird das zweite, stellungsisomere Derivat als gelber, im UV-Licht fluoreszierender Fleck sichtbar.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 480-487 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the bis(sulfonium salt)7 in a solution of Na2CO3 in H2O/EtOH yielded three main products 8-10. The spectroscopic data of 8 were identical to those which led Mithcell and Sondheimer to assign them to cyclodeca[1,2,3-de: 6,7,8-d′e′]dinaphthalene (3). Our investigations show, however, that the correct structural assignment leads to the structure of 7,7a-dihydrodibenzo[de,mn]naphthacene (8).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...