HDAC6-IN-6 (compound 6a) is a potent HDAC6 inhibitor with an IC50 value of 0.025 µM that can penetrate the BBB. It exhibits strong inhibitory activity against AChE and Abeta 1-42 self-aggregation with IC50 values of 0.72 and 3.0 µM, respectively. HDAC6-IN-6 also enhances neurite outgrowth without significant neurotoxicity [1].