Synthesis of highly potent lymphocyte function-associated antigen-1 antagonists labeled with carbon-14 and with stable isotopes, part 3
作者:Bachir Latli、Matt Hrapchak、Guisheng Li、Jon Lorenz、Josh Horan、Carl A. Busacca、Chris H. Senanayake
DOI:10.1002/jlcr.3698
日期:2019.2
The drug candidates (2) and (3) are highly potent LFA-1 inhibitors. They were efficiently prepared labeled with carbon-14 using a palladium-catalyzed carboxylation of an iodo-precursor (5) and sodium formate-14C to afford acid [14C]-(6), which was coupled via an amide bond to chiral amines (7) and (8) in 52% and 48% overall yield, respectively, and with specific activities higher than 56 mCi/mmol and radiochemical purities of 99%. For stable isotopes synthesis, the amine [2H8]-(7) was synthesized in three steps from 2-cyanopyridine-2H4 using Kulinkovich-Szymonik aminocyclopropanation, followed by coupling to L-alanine-2,3,3,3-2H4-N-t-BOC, and then removal of the BOC-protecting group. Amide bond formation with acid (6) gave [2H8]-(2) in 36% overall yield. The amine [13C4,15N]-(8) was obtained in two steps using L-threonine-14C4,15N and then coupled to acid [13C]-(6) to give [13C5,15N]-(3) in 56% overall yield.
候选药物(2)和(3)是高效的 LFA-1 抑制剂。通过钯催化碘前体(5)和甲酸钠-14C 的羧化反应,制备出酸 [14C]-(6),并通过酰胺键将其与手性胺(7)和(8)偶联,制备出带有碳-14 标记的候选药物,总收率分别为 52% 和 48%,比活度高于 56 mCi/mmol,放射化学纯度为 99%。在合成稳定同位素时,[2H8]-(7)胺是通过库林科维奇-西莫尼克(Kulinkovich-Szymonik)氨基环丙烷化法从 2-氰基吡啶-2H4 分三步合成的,然后与 L-丙氨酸-2,3,3,3-2H4-N-t-BOC 偶联,再去除 BOC 保护基。与酸(6)形成酰胺键,得到[2H8]-(2),总收率为 36%。使用 L-苏氨酸-14C4,15N,分两步得到胺[13C4,15N]-(8),然后与酸[13C]-(6)偶联得到[13C5,15N]-(3),总收率为 56%。