Reactions of 4-Nitrophenyl 2-Thiophenecarboxylates with R2NH/R2NH2+ in 20 mol % DMSO (aq). Effects of 5-Thienyl Substituent and Base Strength 


Vol. 34,  No. 7, pp. 2036-2040, Jul.  2013
10.5012/bkcs.2013.34.7.2036


PDF
  Tumbnail

  Abstract

Reactions of 4-nitrophenyl 2-thiophenecarboxylate (1a-e) with R2NH/R2NH2 + in 20 mol % DMSO (aq) have been studied kinetically. The 2nd order kinetics, βnuc = 0.88-0.98, and linear Hammett and Yukawa-Tsuno plots observed for these reactions indicate an addition-elimination mechanism in which the 2nd step is rate limiting. The βnuc value increased with a stronger electron-withdrawing 5-thienyl substituent, the Hammett plots are linear except for X = MeO, and Yukawa-Tsuno plots are linear with ρ = 0.79-1.32 and r = 0.28-0.93, respectively. The ρ value increased and r value decreased with a stronger nucleophile, indicating an increase in the electron density at the C=O bond and a decrease in the resonance demand. These results have been interpreted with enhanced N-C bond formation in the transition state with the reactivity increase.

  Statistics
Cumulative Counts from November, 2022
Multiple requests among the same browser session are counted as one view. If you mouse over a chart, the values of data points will be shown.


  Cite this article

[IEEE Style]

S. Y. Pyun and B. R. Cho, "Reactions of 4-Nitrophenyl 2-Thiophenecarboxylates with R2NH/R2NH2+ in 20 mol % DMSO (aq). Effects of 5-Thienyl Substituent and Base Strength," Bulletin of the Korean Chemical Society, vol. 34, no. 7, pp. 2036-2040, 2013. DOI: 10.5012/bkcs.2013.34.7.2036.

[ACM Style]

Sang Yong Pyun and Bong Rae Cho. 2013. Reactions of 4-Nitrophenyl 2-Thiophenecarboxylates with R2NH/R2NH2+ in 20 mol % DMSO (aq). Effects of 5-Thienyl Substituent and Base Strength. Bulletin of the Korean Chemical Society, 34, 7, (2013), 2036-2040. DOI: 10.5012/bkcs.2013.34.7.2036.

Search
(IN TITLE, AUTHOR, ABSTRACT,KEYWORDS)

Advanced Search ▼

POPULAR KEYWORDS
(TOP 10 KEYWORDS)

Recent Publications
(LAST 3 YEARS)

ISSN(Print) 0253-2964
ISSN(Online) 1229-5949