Internal acyl migration reactions of 1β-O-acyl glucuronides of 2-arylpropionic acids (profens) are of interest because of their possible role in covalent binding to serum proteins and consequent allergic reactions. The stereoselective degradation of 1β-O-acyl glucuronides of enantiomeric 2-phenylpropionic acids (PAs), the basic structures of profens, in phosphate buffer (pH 7.4) at 37°C, has been investigated using HPLC. Apparent first-order degradation of 1β-O-acyl glucuronide and the sequential appearance of 2-, 3- and 4-O-acyl isomers were observed for each enantiomer. Acyl migration was observed to predominate over hydrolysis as in the other profen glucuronides. All the positional isomers and anomers were characterized using NMR and HPLC-NMR. The overall degradation half-life of (R)- and (S)-PA glucuronides was 1.8 and 3.3 h, respectively. These results suggest that (R)-PA glucuronide could be more susceptible to covalent binding to proteins via acyl migration than the corresponding antipode. The lability of the (R)-diastereomer over the antipode is consistent with previous reports on other profen glucuronides. Thus, the diastereomeric PA glucuronides are considered to be the best model compounds for the computation of structural physicochemical parameters to control the stereoselective internal acyl migration of profen glucuronides because PA has the simplest chemical structure of all the profens.
2-arylpropionic acids(profens)的 1β-O-acyl glucuronides(1β-O-酰基
葡糖苷酸)的内部酰基迁移反应很受关注,因为它们可能会与血清蛋白发生共价结合,从而引起过敏反应。在 37°C 的
磷酸盐缓冲液(pH 值为 7.4)中,使用 HPLC 研究了对映体
2-苯基丙酸(PAs)(profens 的基本结构)的 1β-O-acyl
葡萄糖醛酸苷的立体选择性降解。在每种对映体中都观察到了 1β-O-acyl glucuronide 的明显一阶降解以及 2-、3-和 4-O-acyl 异构体的依次出现。与其他
呋喃苯
吡喃
葡萄糖醛酸一样,观察到酰基迁移比
水解占优势。使用核磁共振和 HPLC-NMR 对所有位置异构体和同分异构体进行了表征。(R)-和(S)-PA
葡糖醛酸的总体降解半衰期分别为 1.8 和 3.3 小时。这些结果表明,与相应的反式相比,(R)-PA
葡萄糖醛酸可能更容易通过酰基迁移与蛋白质共价结合。(R)-非对映异构体比对映异构体更易与蛋白质共价结合,这与之前关于其他
呋喃苯
葡糖醛酸的报道一致。因此,非对映异构体 PA
葡糖苷酸被认为是计算结构理化参数以控制络
氨葡糖苷酸立体选择性内部酰基迁移的最佳模型化合物,因为 PA 在所有络
氨葡糖苷酸中具有最简单的
化学结构。