Reactions of Aryl 5-substituted-2-Thiophenecarboxylates Promoted by 4-Z-C<sub>6</sub>H<sub>4</sub>O<sup>−</sup>/4-Z-C<sub>6</sub>H<sub>4</sub>OH in 20 mol % DMSO(aq). Effect of Nucleophile on Acyl-Transfer Reaction
作者:Sang Yong Pyun、Kyu Cheol Paik、Man So Han、Bong Rae Cho
DOI:10.1002/bkcs.10567
日期:2015.12
Nucleophilic substitution reactions of 5‐XC4H2 (S)C(O)OC6H3 ‐2‐Y‐4‐NO2 (1) promoted by 4‐Z‐C6H4O −/4‐Z‐C6H4OH in 20 mol % dimethyl sulfoxide (DMSO)(aq) have been studied kinetically. The reactions exhibited second‐order kinetics with βacyl = −2.52 to −2.83, ρ(x) = 2.81–3.16, βnuc = 0.88–0.04 and βlg = −0.94, respectively. The results have been interpreted with an addition–elimination mechanism in which
5-XC的亲核取代反应4 ħ 2(S)C(O)OC 6 H ^ 3 -2-Y-4-NO 2(1 ×4-Z-C促进)6 ħ 4 ø - / 4-Z-已对20 mol%二甲基亚砜(DMSO)(水溶液)中的C 6 H 4 OH进行了动力学研究。该反应显示出第二级动力学与β酰基 = -2.52至-2.83,ρ(X)= 2.81-3.16,β NUC = 0.88-0.04和β LG 分别为-0.94。结果已通过加成消除机制进行了解释,其中亲核攻击发生在速率确定步骤中。与现有数据的比较表明,速率确定步骤从第二步到第一步是通过亲核试剂从R 2 NH / R 2 NH 2 +到4‐Z‐C 6 H 4 O − / 4‐Z的变化而变化的‐C 6 H 4 OH。