Kinetic Study on Aminolysis of 4-Nitrophenyl Isonicotinate in Acetonitrile: Effect of Amine Basicity on Reactivity and Reaction Mechanism

Bulletin of the Korean chemical society

Min-Young Kim¹  Minah Shin¹  Ik-Hwan Um¹ 

关键词: Aminolysis;    4-Nitrophenyl isonicotinate;    Energy profile;    Stepwise mechanism;    Catalysis;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

A kinetic study is reported on nucleophilic substitution reactions of 4-nitrophenyl isonicotinate (7) with a series of cyclic secondary amines in MeCN. The plots of kobsd vs. [amine] curve upward for the reactions with weakly basic amines (e.g., morpholine, 1-(2-hydroxyethyl)piperazine, and piperazine) but are linear for those with strongly basic amines (e.g., piperidine and 3-methylpiperidine). The curved plots for the reactions with the weakly basic amines are typical for reactions reported previously to proceed through uncatalyzed and catalyzed routes with two intermediates (e.g., a zwitterionic tetrahedral intermediate T± and its deprotonated form T–). In contrast, the linear plots for the reactions with the strongly basic amines indicate that the catalytic route (i.e., the deprotonation process to yield T– from T± by a second amine molecule) is absent. The Brønsted-type plots for Kk2 and Kk3 (i.e., the rate constants for the uncatalyzed and catalyzed routes, respectively) exhibit excellent linear correlations with βnuc = 0.99 and 0.69, respectively. The effect of amine basicity on the reaction mechanism is discussed in detail.

【 授权许可】

Unknown