An orally available HDAC inhibitor that selectively targets HDAC1 and 2 (IC50s = 0.15 and 0.29 µM, respectively), less potently inhibits HDAC3 and 11 (IC50s = 1.66 and 0.59 µM, respectively); induces hyperacetylation of histones, causes cell cycle blockade, and induces apoptosis in cancer cells in vitro.