The screening tests of N-hydroxybenzamides for their HDAC-inhibitory activities led to the discovery of the promising compounds with a 2-naphthylcarbonyl group and with a 1, 4- biphenylcarbonyl group. These compounds were further modified to optimize their physico- chemical profile. As a result, the inhibitor with a 6-amino-2-naphthylcarbonyl was obtained, which showed not only promising growth inhibitions against a panel of tumor cells, but ...