Histone deacetylase inhibitors and uses thereof are provided that have the general formula ##STR00001## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently selected from the group consisting of hydrogen, a substituted or unsubstituted straight chained C.sub.1-12 alkyl, C.sub.2-12 aminoalkyl or C.sub.2-12 oxaalkyl, and a substituted and unsubstituted 3, 4, 5, 6, 7 or 8 membered ring, with the proviso that R.sub.3 and R.sub.4 are not both hydrogen; R.sub.5 is selected from the group consisting of a carbonyl, a substituted or unsubstituted C.sub.1-3 alkyl, a substituted or unsubstituted --C.sub.1-3 alkyl-C(O), a substituted or unsubstituted --C(O)--C.sub.1-3 alkyl, and a substituted or unsubstituted --C(O)C(O)C.sub.1-3 alkyl; M is a substituent capable of complexing with a protein metal ion; and L is a substituent comprising a chain of 3 12 atoms connecting the M substituent to the carbon atom alpha to the L substituent.