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Aminolysis of Y-substituted phenyl X-substituted cinnamates and benzoates: Effect of modification of the nonleaving group from benzoyl to cinnamoyl

Title
Aminolysis of Y-substituted phenyl X-substituted cinnamates and benzoates: Effect of modification of the nonleaving group from benzoyl to cinnamoyl
Authors
Um I.-H.Park Y.-M.Fujio M.Mishima M.Tsuno Y.
Ewha Authors
엄익환
SCOPUS Author ID
엄익환scopusscopus
Issue Date
2007
Journal Title
Journal of Organic Chemistry
ISSN
0022-3263JCR Link
Citation
vol. 72, no. 13, pp. 4816 - 4821
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
(Chemical Equation Presented) A kinetic study is reported for reactions of Y-substituted phenyl X-substituted cinnamates (1a-e and 3a-g) and benzoates (2a-e and 4a-g) with a series of alicyclic secondary amines in 80 mol % H 2O/20 mol % DMSO at 25.0 ± 0.1°C. Reactions of 2,4-dinitrophenyl X-substituted cinnamates (1a-e) and benzoates (2a-e) with amines result in linear Yukawa-Tsuno plots. The ρX values are much smaller for the reactions of 1a-e than for those of 2a-e. A distance effect and the nature of the reaction mechanism (i.e., a concerted mechanism for 1a-e) have been suggested to be responsible for the small ρX values. The Brønsted-type plots for the reactions of 2,4-dinitrophenyl X-substituted cinnamates (1a, 1c, and 1e) with amines are curved with a decreasing βnuc value from 0.65 to 0.3-0.4. The reactions of Y-substituted phenyl cinnamates (3a-g) with morpholine also result in a curved Brønsted plot, while the corresponding reactions of Y-substituted phenyl benzoates (4a-e) exhibit a linear Brønsted plot. It has been concluded that the curved Brønsted plots found for the reactions of the cinnamates (1a, 1c, 1e, and 3a-g) are not due to a change in the rate-determining step (RDS) but due to a normal Hammond effect for a concerted mechanism, that is, an earlier transition state (TS) for a more reactive amine or substrate. © 2007 American Chemical Society.
DOI
10.1021/jo0705061
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자연과학대학 > 화학·나노과학전공 > Journal papers
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