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  • 1
    Electronic Resource
    Electronic Resource
    Matrix Isolation of o-Quinoid Compounds - 6-Imino-2,4-cyclohexadien-1-one and 1,2-Diimino-3,5-cyclohexadiene (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 2029-2037 
    Details
    ISSN: 0947-3440
    Keywords: Matrix isolation ; Rearrangements ; o-Quinoid compounds ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 6-Imino-2,4-cyclohexadien-1-one (1b) and 1,2-diimino-3,5-cyclohexadiene (1c) were generated in high yields from o-azidophenol (5b) and o-azidoaniline (5c), respectively, by irradiation in argon matrices at 10 K or by flash vacuum pyrolysis (FVP) with subsequent trapping of the products in solid argon. The hydrogen shift in the phenylnitrenes 6 formed as primary intermediates is very rapid, and thus the nitrenes are short-lived transients even under the conditions of matrix isolation. Ring expansion to azacycloheptatetraenes was not observed. FVP produces the thermodynamically most stable E/Z isomers of the quinones as the main products. Photolysis of the matrix-isolated quinones results in photostationary equilibria of the E/Z isomers. The stereoisomers were identified by comparison of the matrix IR spectra with ab initio calculations at the RMP2-FC-6/31G(d) level of theory.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961213
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  • 2
    Electronic Resource
    Electronic Resource
    Rearrangements of 2- and 3-FurfurylideneDedicated to Prof. Dr. H. Bürger on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 897-900 
    Details
    ISSN: 0947-3440
    Keywords: Methylenecyclopropene ; Carbene rearrangement ; Furfurylidene ; Matrix isolation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photo- and thermochemistry of diazo(2-furyl)methane (3) and diazo(3-furyl)methane (6) was investigated using the matrix isolation technique. Photolysis of 3 results in the formation of (Z)-pent-2-en-4-yn-1-al (2) in a clean reaction, in agreement with the observation of Shechter et al. Photolysis or pyrolysis of diazo compound 6 yields (s-Z)-(α-formyl)methylenecyclopropene (s-Z-13) as the only detectable product. Carbene 14 and cyclopropene 15 are proposed as intermediates, but not stable under the reaction conditions and thus not directly observed. The reaction sequence 6→13 provides a novel and simple route to methylenecyclopropenes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970518
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  • 3
    Electronic Resource
    Electronic Resource
    Use of a naphthylethylcarbamoylated-β-cyclodextrin chiral stationary phase for the separation of drug enantiomers and related compounds by sub- and supercritical fluid chromatography (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 325-331 
    Details
    ISSN: 0899-0042
    Keywords: enantiomeric separation ; chiral recognition ; derivatized cyclodextrin ; supercritical fluid chromatography ; drug analysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantiomeric separation of a variety of drugs and related compounds was achieved on an (S)-naphthylethylcarbamoylated-β-cyclodextrin (S-NEC-CD) chiral stationary phase (CSP) using sub- and supercritical fluid chromatography (SFC). Compounds previously resolved on native or derivatized cyclodextrin CSPs in liquid chromatography (LC) using reversed phase or polar organic mobile phase modes could be resolved in SFC using a simple carbon dioxide/methanol eluent. Resolution of cromakalim, which is not possible on the S-NEC-CD column in LC, was readily accomplished in SFC. The importance of modifier, temperature, and pressure was assessed in relation to retention, selectivity, and resolution. The nature of the modifier and the modifier concentration were found to be crucial parameters. © 1996 Wiley-Liss, Inc. Contribution of the National Institute of Standards and Technology. Not subject to copyright.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Photochemie von (Z,Z)-2,7-Cyclodecadien-1-on und 4,8-Cyclododecadien-1-on. Synthese und Eigenschaften von Tricyclo[5.3.0.02,8]decan-Systemen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1872-1886 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Photochemistry of (Z,Z)-2,7-Cyclodecadien-1-one and 4,8-Cyclododecadien-1-one. Synthesis and Properties of Tricyclo[5.3.0.02,8]decane SystemsIrradiation of (Z,Z)-2,7-cyclodecadien-1-one (3) yields (Z,Z)-3,7-cyclodecadien-1-one (12) or tricyclo-[5.3.0.02,8]decan-4-one (16), depending on the reaction conditions. Irradiation of 4,8-cyclododecadien-1-one (28) results also in a light-induced transannular [2 + 2] cycloaddition, yielding tetracyclo[7.3.0.02,1003,6]dodecan-1-one (30). Starting from 16, the preparation of tricyclo[5.3.0.02,8]dec-4-ene (19), tricyclo[5.3.0.02,8]dec-4-ene (21) and tricyclo[5.3.0.02,8]deca-3,5-diene (24) is described. The 1H-NMR and 13C—NMR spectra of the newly prepared compounds are discussed. In the case of 19, 21, and 24, the electronic structure is discussed on hand of their PE spectra.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690815
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  • 5
    Electronic Resource
    Electronic Resource
    2-Alkynylcyclopent-2-enols from 2-Alkynylcyclohex-2-enones via 1-Alkynyl-7-oxabicyclo[4.1.0]heptan-2-ones (1996)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 79 (1996), S. 1428-1434 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Alkynylcyclohex-2-enones 1a-c and 2a-c react with H2O2/NaOH in MeOH to afford 1-alkynyl-7-oxabicyclo[4.1.0]heptan-2-ones 3a-c and 4a-c, respectively. The 3-unsubstituted bicyclic epoxy ketones 3a, 3b, and 4a, 4b react further with H2O2/NaOH, undergoing ring contraction and (formal) decarbonylation to give 2-alkynylcy-clopent-2-enols 5a, 5b, and 6a, 6b, respectively. Epoxy ketones 3 are also obtained under neutral conditions on irradiation (λ = 350 nm) of cyclohexenones 1 in air-saturated benzene solution. Similarly, under neutral conditions oxo-cycloalkenecarbonitriles 8 react (thermally) with H2O2 in MeCN to give the oxabicyclic carbonitriles 9.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19960790515
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  • 6
    Electronic Resource
    Electronic Resource
    Stereoselective Synthesis of Alcohols, XLIV. Cyclization of Benzyloxy-substituted (8-Oxo-2-octenyl)boronates (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 1193-1200 
    Details
    ISSN: 0170-2041
    Keywords: Cyclization, stereoselective ; Allylboration, intramolecular ; Transition state conformations, polar effects on ; Boronates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cyclization of (8-oxo-2-octenyl)boronates having benzyloxy substituents in the chain linking the two functional groups gives benzyloxy-substituted 2-vinylcyclohexanols. High asymmetric induction is found for the 4- or 6-benzyloxy-(Z)-octenylboronates 12a and 12c, whereas cyclization of the other isomers studied proceeded in a stereorandom fashion. Possible reasons for this unexpected behavior are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301193
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  • 7
    Electronic Resource
    Electronic Resource
    Stereoselective Synthesis of Alcohols, XLII. Stereoselective Cyclization of (8-Oxo-2-octenyl)boronates to cis- or trans-2-Vinylcyclohexanol (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 771-775 
    Details
    ISSN: 0170-2041
    Keywords: Cyclization, stereoselective ; Allylboration, intramolecular ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Intramolecular allylboration reactions of (8-oxo-2-octenyl)boronates proceed with excellent diastereoselectivity: the E-isomer 1d leads to the trans-2-vinylcyclohexanol (2) with 99.5% d.s., the corresponding Z-isomer 3d cyclizes to give the cis-isomer with a diastereoselectivity exceeding 99.8%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301122
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  • 8
    Electronic Resource
    Electronic Resource
    Stereoselective Synthesis of Alcohols, XLIII. Asymmetric Induction on the Intramolecular Allylboration Reaction of (8-Oxo-2-octenyl)boronates (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 1185-1191 
    Details
    ISSN: 0170-2041
    Keywords: Cyclization, stereoselective ; Allylboration, intramolecular ; Boronates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cyclization of (8-oxo-2-octenyl)boronates having methyl substituents in the chain linking the two functional groups proceeds with complete simple diastereoselectivity and with induced diastereoselectivity of 85 to 〉 98% to give methylsubstituted 2-vinylcyclohexanols.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301192
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  • 9
    Electronic Resource
    Electronic Resource
    Do rats show a behavioral sensitivity to low-level magnetic fields? (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 335-336 
    Details
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160511
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  • 10
    Electronic Resource
    Electronic Resource
    60 Hz electric fields and incandescent light as aversive stimuli controlling the behavior of rats responding under concurrent schedules of reinforcement (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 19 (1998), S. 210-221 
    Details
    ISSN: 0197-8462
    Keywords: aversive stimuli ; incandescent light ; electric fields ; reinforcement schedules ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Several reports have shown that animals will sometimes engage in behaviors that reduce their exposure to a 60 Hz electric field (E-field). The field, therefore, can function as an aversive stimulus. In other studies, the E-field at equivalent strengths failed to function as an aversive stimulus. The present experiment, using rats, demonstrates how factors other than field strength can influence whether a subject engages in behavior that reduces field exposure. The general design consisted of giving the rat a choice between two alternatives, one of which sometimes included an added stimulus. Each subject was trained to press each of two levers to obtain food. Pressing one lever was reinforced intermittently under a variable interval 2 min schedule (VI 2); pressing the other lever was reinforced by a second VI 2 schedule operating independently of the first. Under this concurrent schedule the rat spent 50% of the daily 50 min session responding to each of the levers, indicating that they were equally “valued.” Next, while the schedules remained in effect, the first response to one of the levers turned on a 100 kV/m E-field which remained on until the rat pressed the other lever. The time spent responding under the schedule associated with the field was reduced by about 5-10%. When the procedure was changed so that no lever presses produced food, i.e., extinction, but the added stimulus contingency remained, the rats spent even less time in the presence of the field. Similar outcomes were observed during both the concurrent food or extinction schedules when incandescent light was used. Thus, both an E-field and incandescent light functioned as aversive stimuli, but the magnitude of the aversiveness was small. Aversiveness depended not only on stimulus intensity, but also on behavioral factors. Bioelectromagnetics 19:210-221, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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