A potent HDAC inhibitor that inhibits HDAC2 and HDAC6 with IC50 values of 0.119 and 434 nM; ineffective against HDAC4 (IC50 = >1,000 nM); inhibits the growth of HCT116 cells and HuT-78 cells (GI50 = 29.4 and 1.4 μM, respectively) more effectively than human dermal fibroblasts (GI50 = >100 μM)