Synthesis and Biological Evaluation of 2-Amino-1-phenyl-benzimidazole Derivatives as BACE1 Inhibitors

Background: Alzheimer’s disease (AD), a chronic neurodegenerative disorder predominantly occurs among the elderly, is the leading cause of dementia. The accumulation of β-amyloid (Aβ) is considered the main pathogenies of AD, and β-site APP-cleaving enzyme 1 (BACE1) plays an important role in the formulation of Aβ. Objective: In order to find a new scaffold as BACE1 inhibitors, a series of novel 2-amino-1-phenylbenzimidazole derivatives were designed and synthesized in this work. Methods: Using our previous L-5 as a lead compound, we applied a scaffold hopping method and merged 2-amino-1-methyl-4-phenyl-1H-imidazol-5 (4H)-one into benzimidazole, so a novel class of BACE1 inhibitors T1~T20 with the structure of 2-amino-1-phenyl-benzimidazole were designed and synthesized. Results: The biological activity evaluation indicated that the target compounds showed inhibitory activities against BACE1, with T14 being the most potent (IC50 = 0.45 μM), it also exhibited good logP value and tPSA. The docking studies indicated that compound T14 could form important hydrogen bonds with Asp289 and Asp93. Conclusion: Compound T14 could be used as a potential BACE1 inhibitor for further modification to treat AD.