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Elimination Reactions of ( E)-2,4,6-Trinitrobenzaldehyde O-Benzoyloximes Promoted by R2NH/ R2NH2 + in 70 mol% MeCN (aq). Effects of the β-Aryl Group and Leaving Group on Nitrile-Forming Transition States.
- Source :
-
Bulletin of the Korean Chemical Society . Jun2016, Vol. 37 Issue 6, p871-876. 6p. - Publication Year :
- 2016
-
Abstract
- Elimination reactions of ( E)-2,4,6-( NO2 ) 3C6H2CH NOC(O) C6H4X ( 3) promoted by R2NH/ R2NH2 + in 70 mol% MeCN (aq) have been studied. The reactions produced elimination products and exhibited second-order kinetics. The β and |βlg| values remained nearly the same for all leaving groups and bases. The results can be described by the negligible pxy interaction coefficient, pxy = ∂β/∂p Klg = ∂βlg/∂p KBH ≈ 0, which provides a strong support for the (E1cb)irr mechanism. For eliminations from ( E)-ArCHNOC(O)C6H4X ( 1, 3) and ( E)-2,4,6-(NO2)3C6H2CHNOAr′ ( 2, 3), the change of the β-aryl group (Ar) from 2,4-dinitrophenyl ( 1) to 2,4,6-trinitrophenyl ( 3) increased the rate by 270-fold without appreciable change in the transition state structure. On the other hand, the leaving group (OAr′) variation from benzoate ( 3) to 4-nitrophenoxy ( 2) induced a change in reaction mechanism from (E1cb)irr to E2. These results have been attributed to the cyclic transition state for the nitrile-forming eliminations involving the benzoate leaving group. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02532964
- Volume :
- 37
- Issue :
- 6
- Database :
- Academic Search Index
- Journal :
- Bulletin of the Korean Chemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 115898394
- Full Text :
- https://doi.org/10.1002/bkcs.10791