Among these, compound 11 with L-alanine in place of L-valine showed the most potent and selective inhibitory effects on HDAC1-3 (HDAC1, IC50 = 1.3 nM; HDAC2, IC50 = 1.6 nM; and HDAC3, IC50 = 3.2 nM), and promising anti-proliferative activity against cancer cell lines Molt-4 and A549 (Molt-4, GI50 = 2.1 nM; A549, GI50 = 7.5 nM). The gene discussed is HDAC1; the disease is cancer.