An HDAC inhibitor (IC50s = 0.3, 2, 0.6, and 4.1 nM for HDAC1, -2, -3, and -6, respectively); selective for these HDACs over HDAC4, -5, -7, -8, and -9 (IC50s = 1,970, 352, >20,000, >15,000, and >15,000 nM, respectively); reduces H3K9ac and H4K12ac in primary mouse neuronal cells (EC50s = 100 nM for both)