Discovery of multitarget-directed ligands (MTDLs), targeting different factors simultaneously to control the complicated pathogenesis of Alzheimer’s disease (AD), has become an important research area in recent years. Both phosphodiesterase 9A (PDE9A) and butyrylcholinesterase (BuChE) inhibitors could participate in different processes of AD to attenuate neuronal injuries and improve cognitive impairments. However, research on MTDLs combining the inhibition of PDE9A and BuChE simultaneously has not been reported yet. In this study, a series of novel pyrazolopyrimidinone–rivastigmine hybrids were designed, synthesized, and evaluated in vitro. Most compounds exhibited remarkable inhibitory activities against both PDE9A and BuChE. Compounds 6c and 6f showed the best IC₅₀ values against PDE9A (6c, 14 nM; 6f, 17 nM) together with the considerable inhibition against BuChE (IC₅₀, 6c, 3.3 μM; 6f, 0.97 μM). Their inhibitory potencies against BuChE were even higher than the anti-AD drug rivastigmine. It is worthy mentioning that both showed moderate selectivity for BuChE over acetylcholinesterase (AChE). Molecular docking studies revealed their binding patterns and explained the influence of configuration and substitutions on the inhibition of PDE9A and BuChE. Furthermore, compounds 6c and 6f exhibited negligible toxicity, which made them suitable for the further study of AD in vivo.

中文翻译：

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发现新型吡唑并嘧啶酮衍生物作为磷酸二酯酶9A抑制剂，具有抑制丁酰胆碱酯酶的能力，可治疗阿尔茨海默氏病

同时靶向不同因素以控制阿尔茨海默病（AD）复杂发病机理的多靶标配体（MTDL）的发现已成为近年来的重要研究领域。磷酸二酯酶9A（PDE9A）和丁酰胆碱酯酶（BuChE）抑制剂均可参与AD的不同过程，以减轻神经元损伤并改善认知障碍。然而，尚未报道对同时抑制PDE9A和BuChE的MTDLs的研究。在这项研究中，一系列新颖的吡唑并嘧啶，利凡斯的明杂种的设计，合成，并评价在体外。大多数化合物对PDE9A和BuChE均显示出显着的抑制活性。化合物6c和6f显示出最好的IC ₅₀对PDE9A的值（图6c，14纳米; 1207米，17纳米）连同对所述的BuChE抑制相当（IC ₅₀，图6c，3.3μM; 1207米，0.97μM）。它们对BuChE的抑制作用甚至比抗AD药物rivastigmine还要高。值得一提的是，两者对BuChE的选择性都比乙酰胆碱酯酶（AChE）中等。分子对接研究揭示了它们的结合模式，并解释了构型和取代对PDE9A和BuChE抑制的影响。此外，化合物6c和6f的毒性可忽略不计，这使其适合于AD的进一步研究体内。