Histone deacetylase 6 (HDAC6) catalyses the removal of acetyl groups from the lysine residues of a series of non-histone proteins, e.g., α-tubulin, Hsp90 and cortactin. The design of selective inhibitors of HDAC6 is related with important outcomes in the oncological, immunological and neurological fields. Herein, we describe the design, synthesis and pharmacological evaluation of a series of N-acylhydrazones (NAH) designed from the trichostatin A as HDAC6 inhibitors. The use of the phenyl linker in the design of the compounds led to HDAC6 selectivity among the HDAC family. Para-substituted phenyl-hydroxamic acids presented a more potent inhibition of HDAC6 than their meta-substituted analogs. The N- and C- methylation of the NAH framework attached to para-substituted phenyl-hydroxamic unit was evaluated and the compound LASSBio-1911 was identified as a potent and selective HDAC6 inhibitor (IC₅₀ = 15 nM). In the next step, we evaluated the influence of the cap group. We found that the use of different aromatic and heteroaromatic rings did not influence the inhibition of HDAC6. Some of these compounds were able to reduce significantly cell migration, corroborating their inhibitory profile against HDAC6. On the other hand, an analysis of their antiproliferative activity against different tumor cell lines showed that they can induce cell cycle arrest or induce apoptosis through caspase 3/7 activation, with particular relevance for hepatocellular carcinoma (HepG2) cells. References Rodrigues, D. A.; Ferreira-Silva, G. A.; Ferreira, A. C.; Fernandes, R. A.; Kwee, J. K.; Sant'Anna, C. M.; Ionta, M.; Fraga, C. A. M. J. Med. Chem., 2016, 59, 655-706. Rodrigues, D. A.; Thota, S.; Fraga, C. A. M. Mini-Rev. Med. Chem., 2016, 16, 1175-1184. Pinheiro, P. S. M.; Rodrigues, D. A.; Sant'Anna, C. M. R.; Fraga, C. A. M. Int. J. Quantum Chem., 2018;e25720.