Library

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 2020-2022
  • 1995-1999  (3)
  • 1960-1964
  • 1935-1939
  • 1998  (3)
  • Reaction mechanisms
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    JBIC 3 (1998), S. 559-560 
    ISSN: 1432-1327
    Keywords: Key wordsXanthine oxidase ; Molybdenum enzymes ; Reaction mechanisms ; Electron paramagnetic resonance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-2234
    Keywords: Key words: Spin-coupled approach ; 1 ; 3-Dipolar cycloadditions ; Reaction mechanisms ; Valence-bond theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. The electronic mechanism for the gas-phase 1,3-dipolar cycloaddition of fulminic acid (HCNO) to ethyne is studied through a combination of modern valence-bond theory in its spin-coupled (SC) form and intrinsic reaction coordinate calculations utilizing a complete-active-space self-consistent field wavefunction. It is shown that the concerted reaction follows a “heterolytic” route, during which three orbital pairs corresponding to three distinct bonds in the reactants (an in-plane π bond in ethyne, and a C-N and an N-O in-plane bond in HCNO) shift simultaneously to create the two new bonds closing the isoxazole ring and a nitrogen lone pair. The analysis of the SC wavefunction strongly suggests that the reacting system remains nonaromatic throughout the most important part of the cycloaddition process. This investigation provides the first demonstration of an alternative SC description of a bond rearrangement, achieved through the movement of singlet orbital pairs through space, during which at least one of the orbitals within a pair becomes completely detached from the atomic centre with which it is associated initially and ends up localized about another centre.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 2743-2746 
    ISSN: 1434-193X
    Keywords: Arenes ; Benzene ; Toluene ; Chlorobenzene ; Benzoylation ; Acylations ; Reaction mechanisms ; Bismuth trifluoromethanesulfonate ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A mechanism for acylations catalyzed by bismuth(III) triflate (1) is proposed in the case of the benzoylation of benzene, toluene, and chlorobenzene. With Bz2O as a reagent, 1 acts as a Lewis acid and allows the benzoylation of toluene. It is almost completely recovered after the reaction. With BzCl, 1 promotes an exchange reaction which generates BzOTf, which is the active species of the benzoylation. In this latter case, the reaction leads to the formation of TfOH which finally reacts with BiCl3 to partially regenerate 1. The power of the Bz2O/1 system is less than that of BzCl/1, which allows not only the benzoylation of toluene but also that of benzene and deactivated chlorobenzene. The activity of 1 is much higher than that of other metallic triflates previously reported, and is comparable with that of TfOH, however it also has the advantage that the triflate moieties are more easily recoverable.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...