– H3R antagonist 4 (compound 11l) serves as a dual inhibitor of cholinesterases and histamine H3 receptors (H3R), demonstrating IC50 values of 7.04 μM (eeAChE), 9.73 μM (hAChE)(reversible), and 1.09 nM (H3R). It effectively inhibits both self and Cu2+-induced Aβ1-42 aggregation at 95.48% and 88.63%, respectively, and degrades Aβ1-42 protofibrils with 80.16% and 89.30% efficiency under similar conditions. Additionally, H3R antagonist 4 possesses the chelating capability for biometals Cu2+, Zn2+, Al3+, and Fe2+. It significantly reduces tau protein hyperphosphorylation induced by Aβ1-42, inhibits RSL-3 induced apoptosis and ferroptosis in PC12 cells, and shows optimal blood-brain barrier permeability and intestinal absorption characteristics in hCMEC/D3 and hPepT1-MDCK cells, respectively. Moreover, the compound improves learning and memory impairments in an Alzheimer’s mouse model induced with scopolamine.