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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 1964-1971 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Solvolysis of 2-Cycloalkyl-2-phenylethyl Tosylates2-Cyclohexyl-2-phenylethyl tosylate (1 a) is solvolyzed in solvents of different ionization and nucleophilic strengths. The alcohols and esters produced have been determined quantitatively. The extents of 1,2-migration of phenyl, cyclohexyl and hydrogen have been calculated from the reaction products (Table I). The reaction kinetics of l a in various solvents compared with that of 2-phenylethyl tosylate (1 d) shows that the cyclohexyl group in the P-position effects an acceleration of reaction (Figure 1).
    Notes: (2-Cyclohexyl-2-phenyläthyl)tosylat (1 a) wird in Lösungsmitteln verschiedener Ionisierungsstärke und Nucleophilie solvolysiert; die entstehenden Alkohole und Ester werden quantitativ bestimmt. Aus den Reaktionsprodukten (Tabelle 1) sind die Anteile der 1,2-Wanderung von Phenyl, Cyclohexyl und Wasserstoff ermittelt worden. Die Reaktionskinetik von la in verschiedenen Lösungsmitteln (Abbildung 1 ) zeigt, daß die Cyclohexylgruppe am β-Kohlenstoffatom eine Reaktionsbeschleunigung gegenüber (2-l)tosylat (1 d) bewirkt.
    Additional Material: 1 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 1637-1650 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Solvolysis of 2-Cyclohexyl-2-phenylethyl Tosylates Substituted at the Phenyl RingThe solvolysis of 2-cyclohexyl-2-phenylethyl tosylates substituted at the phenyl ring by X = p-H (1), p-NO2, p-IO2, p-CN, p-COCH3, m-Cl, m-F, p-Cl, p-Br, p-CH3, and p-OCH3 (2a - k) in ethanol, acetic acid, and formic acid has been investigated. The total rate constants kt were determined and the obtained values together with corresponding Hammet σ constants were used to calculate the rate constants kΔ (for aryl-assisted reactions) and ks (for non-assisted reactions). The acetolysis values FkΔ and ks of 2-cyclohexyl-2-phenylethyl tosylate (1) at 100°C are in good agreement with those formerly obtained on the basis of product analysis.
    Notes: Es wurde die Solvolyse von 2-Cyclohexyl-2-phenylethyltosylaten, die am Phenylring durch X = p-H (1), p-NO2, p-IO2, p-CN, p-COCH3, m-Cl, m-F, p-Cl, p-Br, p-CH3 und p-OCH3 (2a - k) substituiert sind, in Ethanol, Essigsäure und Ameisensäure untersucht. Die Gesamtgeschwindigkeitskonstanten kt wurden bestimmt und daraus mit den entsprechenden Hammet-Konstanten σ die Geschwindigkeitskonstanten kΔ (für Reaktionen unter Beteiligung der Arylgruppe) und ks (für Reaktionen ohne Beteiligung der Arylgruppe) berechnet. Die Werte FkΔ und ks für die Acetolyse von 2-Cyclohexyl-2-phenylethyltosylat (1) bei 100°C stimmen gut mit denen überein, die früher aufgrund von Produktanalysen erhalten wurden.
    Additional Material: 4 Ill.
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  • 3
    ISSN: 0192-8651
    Keywords: bond polarizabilities ; localized orbitals ; bicyclo[1.1.1]pentanes ; NMR coupling constants ; CLOPPA-IPPP ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: In the present work, the relationship between the large substituent effects on 3J(C1H) in 1-X-3-M-bicyclo[1.1.1]pentanes, I, and the polarizability of the bridgehead C3(SINGLE BOND)Mα bond is investigated. The existence of such a relationship is suggested by the finding that the effect of an electronegative substituent X on 3J(C1Mα) couplings in I (M=H) is due to a distortion of the C3(SINGLE BOND)H bond toward the C1 center, which enhances the Fermi contact interaction. If such distortion originates in an electrostatic effect, then in other members of this series it can be expected that the substituent effects on 3J(C1Mα) couplings should depend strongly on the C3(SINGLE BOND)Mα bond polarizability. Two approaches are followed. First, the ab initio CLOPPA-IPPP method is applied to study the C3(SINGLE BOND)Mα bond contribution to the molecular static polarizability tensor in I (M=H, F, CH3). Such bond polarizabilities are found to follow the same trend as calculated as well as experimentally determined substituent effects on 3J(C1Mα) couplings, which were measured as part of this work in I [X=H, Cl; M=F, CH3 and X=OCH3; M=Sn(CH3)3]. Second, 3J(C1Mα) couplings (M=H, CH3) are calculated at an ab initio level for X=H, F, and they are compared with those obtained in the parent compound (X=H) if the calculation is carried out in the presence of an inhomogeneous electric field.   © 1998 John Wiley & Sons, Inc.   J Comput Chem 19: 181-188, 1998
    Additional Material: 1 Ill.
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  • 4
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: UV Irradiation of (Z)- and (E)-1(10)-unsaturated 5,10-secosteroids 1-4 in acetone solution effected, besides (Z/E)-isomerization, (i) a stereospecific epoxidation (only in the presence of O2), which, depending on the configuration ((Z) or (E)) in the starting steroid, gave cis-epoxides 5 and 8 (from the (Z)-compounds 1 and 3) or trans-epoxides 6,9, and 10 (from the (E)-compounds 2 and 4), and (ii) oxidative acetone addition to the olefinic double bond producing 1-acetonyl derivatives 7 and 11a, b.
    Additional Material: 1 Ill.
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  • 5
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Upon heating in AcOH, the stereoisomeric (Z)- and (R)-6,9-dioxocyclodex-3-enyl derivatives, 5 and 6, respectively, obtained by HgO/I2 oxidation of 5-hydroxy-8-oxo-8,14-seco-5α-androstane-3β,17β-diyl diacetate (3), undergo an unusual intramolecular rearrangement to give the corresponding unsaturated (5R,9R)- and (5R,9S)-spiro-lactones 7 and 8, respectively. Hydroxylation of the C=C bond in 7 and 8, and subsequent glycol cleavage of the resulting diols 9 and 10 afforded the epimeric spiro-lactones (5R,9S)-11 and (5R,9R)-14, respectively, and in both cases, the ring-D-containing fragments 12 and 13.
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