Hydroxamic acids were designed, synthesized, and evaluated for their ability to selectively inhibit human histone
deacetylase 6 (HDAC6). Several inhibitors, including compound 14 (BRD9757), exhibited excellent potency and selectivity
despite the absence of a surface-binding motif. The binding of these highly efficient ligands for HDAC6 is rationalized via
structure−activity relationships. These results demonstrate that high selectivity and potent inhibition of HDAC6 can be achieved
through careful choice of linker element only.