Reactions of 2,4‐dinitrophenyl 5‐substituted‐2‐thiophenecarboxylate promoted by <scp>4‐ZC<sub>6</sub>H<sub>4</sub>O<sup>−</sup></scp>/<scp>4‐ZC<sub>6</sub>H<sub>4</sub>OH</scp> in 20 mol% <scp>DMSO</scp>(aq). Effects of leaving group and nucleophile on the acyl transfer reactions
作者:Sang Yong Pyun、Kyu Cheol Paik、Man So Han、Seung Taek Hong、Bong Rae Cho
DOI:10.1002/bkcs.12780
日期:2023.11
The kinetics of nucleophilic substitution reactions involving 2,4-dinitrophenyl 5-substituted-2-thiophenecarboxylate were studied kinetically with 4-Z-C6H4O−/4-Z-C6H4OH, which facilitated the reactions, in 20 mol% DMSO(aq). The reactions followed second-order kinetics and exhibited βacyl = −2.34 to −2.92, ρ(Y) = 2.71–3.39, βnuc = 0.74–0.83, and |βlg| = 0.40–0.57. Based on the interpretation of the
使用促进反应的 4-ZC 6 H 4 O − /4-ZC 6 H 4 OH 在 20 mol% DMSO 中对涉及 2,4-二硝基苯基 5-取代-2-噻吩甲酸酯的亲核取代反应动力学进行了动力学研究(阿克)。反应遵循二级动力学,表现出β acyl = -2.34 至 -2.92,ρ (Y) = 2.71–3.39,β nuc = 0.74–0.83,并且 | β lg | = 0.40–0.57。基于对结果的解释,我们得出结论,该反应遵循加成-消除机制,其中第一步是速率决定步骤(rds)。4-ZC 6 H 4 O -促进的反应的过渡态结构几乎保持不变,只是离去基团从4-硝基苯氧基变为2,4-二硝基苯氧基。4-ZC 6 H 4 O -促进反应的机理与R 2 NH促进反应相似,不同之处在于前者以第一步rds进行,后者以rds变化进行。第一步的第二步使用更强的亲核试剂。