Glycogen synthase kinase-3β (GSK-3β) is a potential target in the field of Alzheimer’s disease drug discovery. We recently reported a new class of 9H-pyrimido[4,5-b]indole-based GSK-3β inhibitors, of which 3-(3-((7-chloro-9H-pyrimido[4,5-b]indol-4-yl)(methyl)amino)piperidin-1-yl)propanenitrile (1) demonstrated promising inhibitory potency. However, this compound underwent rapid degradation by human liver microsomes. Starting from 1, we prepared a series of amide-based derivatives and studied their structure–activity relationships against GSK-3β supported by 1 µs molecular dynamics simulations. The biological potency of this series was substantially enhanced by identifying the eutomer configuration at the stereocenter. Moreover, the introduction of an amide bond proved to be an effective strategy to eliminate the metabolic hotspot. The most potent compounds, (R)-3-(3-((7-chloro-9H-pyrimido[4,5-b]indol-4-yl)(methyl)amino)piperidin-1-yl)-3-oxopropanenitrile ((R)-2) and (R)-1-(3-((7-bromo-9Hpyrimido[4,5-b]indol-4-yl)(methyl)amino)piperidin-1-yl)propan-1-one ((R)-28), exhibited IC50 values of 480 nM and 360 nM, respectively, and displayed improved metabolic stability. Their favorable biological profile is complemented by minimal cytotoxicity and neuroprotective properties.
糖原合成酶激酶-3β(GSK-3β)是阿尔茨海默病药物发现领域的潜在靶点。我们最近报道了一类新的基于9H-嘧啶并[4,5-b]吲哚的GSK-3β抑制剂,其中3-(3-((7-氯-9H-嘧啶并[4,5-b]吲哚-4-基)(甲基)氨基)哌啶-1-基)丙腈(1)展现出有希望的抑制效能。然而,这种化合物在人类肝微粒体中迅速降解。从1开始,我们制备了一系列基于酰胺的衍生物,并通过1微秒分子动力学模拟研究了它们与GSK-3β的结构活性关系。通过确定立体中心处的优势构型,这一系列的生物效能得到了显著增强。此外,引入酰胺键被证明是消除代谢热点的有效策略。最有效的化合物,(R)-3-(3-((7-氯-9H-嘧啶并[4,5-b]吲哚-4-基)(甲基)氨基)哌啶-1-基)-3-氧代丙腈((R)-2)和(R)-1-(3-((7-溴-9H-嘧啶并[4,5-b]吲哚-4-基)(甲基)氨基)哌啶-1-基)丙酮((R)-28),分别展现出480 nM和360 nM的IC50值,并表现出改善的代谢稳定性。它们有利的生物特性得到了最低的细胞毒性和神经保护性质的补充。