Cyclization of the Acyl Glucuronide Metabolite of a Neutral Endopeptidase Inhibitor to an Electrophilic Glutarimide: Synthesis, Reactivity, and Mechanistic Analysis
作者:Xiaoli Meng、James L. Maggs、David C. Pryde、Simon Planken、Rosalind E. Jenkins、Torren M. Peakman、Kevin Beaumont、Christopher Kohl、B. Kevin Park、Andrew V. Stachulski
DOI:10.1021/jm0706766
日期:2007.11.1
unstable thioesters. Imide 4 acylated eight lysine Nepsilon-amino groups of human serum albumin. Rapid cyclization of 3 was attributed to attack on the ester linkage by an unusually nucleophilic glutaramide NH (pKa in 2 = 9.76). N-propyl 3 was refractory to acyl migration and cyclization. This suggested a synthetic strategy for preparing analogues of 2 that form chemically stable acyl glucuronides.
中性内肽酶抑制剂 (2R)-2-[(1-[(5-ethyl-1,3,4-thiadiazol-2-yl)amino]carbonyl}cyclopentyl)methyl]pen tanoic acid 2 代谢为酰基葡萄糖醛酸3. 前所未有的是,在 pH 7.4 时,3 不经历酰基葡萄糖醛酸苷的 O-酰基迁移特征,而是快速、消除环化(37 摄氏度下的 t1/2,10.2 分钟)为戊二酰亚胺 4。葡萄糖醛酸苷 3 是通过酰化有效合成的带有 N-苄氧基甲基保护的苄基葡萄糖醛酸 2. 葡萄糖醛酸和酰亚胺在 pH 7.4 的水溶液中与氨基酸和谷胱甘肽快速反应,形成稳定的酰胺和不稳定的硫酯。酰亚胺 4 酰化人血清白蛋白的八个赖氨酸 Nepsilon-氨基。3 的快速环化归因于异常亲核的戊二酰胺 NH(2 中的 pKa = 9.76)对酯键的攻击。N-丙基 3 不易发生酰基迁移和环化。这提出了一种用于制备