Hydrolytic removal of the chlorinated products from the oxidative free-radical-induced degradation of chloroethylenes: acid chlorides and chlorinated acetic acids
employed to compare reactivities of carboxylates with those of other leavinggroups previously included in the nucleofugality scale, and also to estimate the solvolysis rates of various carboxylates. It is confirmed that the inductive effect is the most important variable governing the reactivities of halogenated carboxylates in solution. Moreover, both the Hammett correlation and the solvolytic activation
一系列脂肪族羧酸盐的离去基团能力(离核能力)是通过从 X,Y 取代的二苯甲基羧酸盐在一系列含水乙醇混合物中的溶剂分解速率常数中确定的离核剂特异性参数(Nf 和 sf)获得的。线性自由能关系 (LFER) 方程:log k = sf (Ef + Nf)。这些值可用于比较羧酸盐与先前包含在核疏散量表中的其他离去基团的反应性,也可用于估计各种羧酸盐的溶剂分解速率。已经证实,诱导效应是控制溶液中卤代羧酸盐反应性的最重要变量。而且,Hammett 相关性和溶剂分解活化参数都揭示了诱导效应对烷基取代的羧酸盐的核疏散性的强烈影响。反应常数 (sf) 表明具有较弱离去基团的羧酸盐底物通过较晚的、更类似碳正离子的过渡态溶剂分解,这与哈蒙德假设一致。此外,由于对产生更稳定的二苯甲基离子的过渡态溶剂化的需求较弱,其中发生更有效的电荷离域,此处研究的大多数离去基团获得的反应常数(sf)随着离子的极性增加而增加。溶剂减少。反应常数
Triple coumarin-based 5-fluorouracil prodrugs, their synthesis, characterization, and release kinetics
作者:Yasser Fakri Mustafa
DOI:10.1016/j.molstruc.2023.137415
日期:2024.4
5-FU prodrugs, which were divided into three series of compounds, A, B, and C. The chemical structures of these prodrugs are confirmed by using FTIR, 1H-NMR, 13C-NMR, and mass spectrophotometers. The chemical stability of these prodrugs in simulated gastric and intestinal fluids as well as their release in human serum were measured spectrophotometrically. The outcomes showed that the synthetic prodrugs