136367-44-7Relevant academic research and scientific papers
Kinetic study on aminolysis of y-substituted-phenyl x-substituted- benzoates: Effects of substituents x and y on reactivity and reaction mechanism
Jeon, Seong Hoon,Kim, Hyun Soo,Han, Young Joon,Kim, Min-Young,Um, Ik-Hwan
, p. 471 - 476 (2014/03/21)
A kinetic study on aminolysis of 2-chloro-4-nitrophenyl X-substituted-benzoates (2a-k) in 80 mol % H2O/20 mol % DMSO at 25.0 oC is reported. The Bronsted-type plot for the reactions of 2-chloro-4-nitrophenyl benzoate (2g) with a series of cyclic secondary amines curves downward (e.g., β1 = 0.25, β2 = 0.85 and pKa o = 10.3), which is typical of reactions reported to proceed through a stepwise mechanism with a change in ratedetermining step (RDS). The Hammett plot for the reactions of 2a-k with piperidine consists of two intersecting straight lines, while the corresponding Yukawa-Tsuno plot exhibits an excellent linear correlation with ρX = 1.15 and r = 0.59. Thus, it has been concluded that the nonlinear Hammett plot is not due to a change in RDS but is caused by stabilization of substrates through resonance interactions between the electron-donating substituent and the C=O bond. Substrates possessing a substituent at the 2-position of the leaving aryloxide deviate negatively from the curved Bronsted-type plot for the reactions of Y-substituted-phenyl benzoates (3ai), implying that the steric hindrance exerted by the substituent at the 2-position is an important factor which governs the reactivity of Y-substituted-phenyl benzoates.
