H3R antagonist 2 (Compound 23) is a multitarget histamine H 3 receptor (H 3 R) antagonist with a K i of 170 nM for hH 3 R. H3R antagonist 2 shows inhibitory effects with IC 50 values of 180, 880 and 775 nM for acetylcholinesterase , butyrylcholinesterase and human monoamine oxidase B (hMAO B) , respectively. H3R antagonist 2 shows favorable anti-neuropathic pain and memory-enhancing effects. H3R can across BBB.