作者:Charles S. Elmore、Scott Landvatter、Peter N. Dorff、Mark E. Powell、David Killick、Timothy Blake、James Hall、J. Richard Heys、John Harding、Rebecca Urbanek、Glen Ernst
DOI:10.1002/jlcr.3186
日期:2014.5.15
In support of a program to develop an alpha 7 agonist as a treatment for Alzheimer's disease, three drug candidates, 1, 2, and 3, were prepared in labeled forms. Compound 1 was prepared in C-14 labeled form by lithiation of [2,6-14C2]2-chloropyridine and subsequent coupling with spirooxirane-2,3'-quinuclidine. When this same coupling was attempted using [3,4,5,6-2H4]2-chloropyridine, alcohol [2H6]-6 was the major product indicating that the primary isotope effect for the lithiation step was significant enough to shift the reaction pathway. Therefore, an alternate site of labeling was used to prepare [2H4]-1. [13C5]-2 was prepared in five steps from [13C5]2-furoic acid, but the C-14 labeled compound used [14C2]-1 as the starting material instead. [14C2]-3 was prepared in two steps from [carbonyl-14C]nicotinic acid.
为了支持开发α 7激动剂作为阿尔茨海默病治疗的项目,准备了三种药物候选物,1、2和3,采用标记形式合成。化合物1通过锂化[2,6-14C2]2-氯吡啶,并随后与螺氧杂环-2,3'-奎宁结合,制备成C-14标记形式。当尝试使用[3,4,5,6-2H4]2-氯吡啶进行相同的结合时,产生了酒精[2H6]-6作为主要产物,这表明锂化步骤的主要同位素效应足够显著,以改变反应路径。因此,采用了另一种标记位点来制备[2H4]-1。[13C5]-2是通过五步从[13C5]2-呋喃酸合成的,但C-14标记的化合物则是以[14C2]-1为起始材料。[14C2]-3是通过两步从[羰基-14C]烟酸合成的。