A process for preparing unsaturated esters useful as intermediates for HDAC inhibitors, by reacting an aldehyde or ketone having the following formula I: ##STR00001## wherein R.sub.1 is an aromatic group or a combined aliphatic and aromatic group; X is --O--, --S--, --COO--, --OOC--, --CONR.sub.7--, or --R.sub.7NCO--; L.sub.1 an aliphatic linking group, an aromatic linking group, or a combined aliphatic and aromatic linking group; R.sub.2 and R.sub.3 are each independently hydrogen, a hydroxy group, an alkoxy group, an amino group, a carboxyl group, an amide group, an ester group, a carbamate group, an aliphatic group, an aromatic group, a combined aliphatic and aromatic group, R.sub.2 and R.sub.3 together are .dbd.O, or one of R.sub.2 and R.sub.3 form a double bond with one of R.sub.4 and R.sub.5; R.sub.4 and R.sub.5 are each independently hydrogen, a hydroxy group, an alkoxy group, an amino group, a carboxy group, an amide group, an ester group, a carbamate group, an aliphatic group, an aromatic group, a combined aliphatic and aromatic group, or one of R.sub.4 and R.sub.5 form a double bond with one of R.sub.2 and R.sub.3; R.sub.6 is hydrogen, an aliphatic group, an aromatic group, or a combined aliphatic and aromatic group; R.sub.7 is hydrogen, an aliphatic group, an aromatic group, or a combined aliphatic and aromatic group; m is 0 or 1; n is 0 or 1; and p is 0 or 1; with an ester having the following formula II: ##STR00002## wherein R.sub.8 is an aliphatic group, an aromatic group, or a combined aliphatic and aromatic group; R.sub.9 and R.sub.10 each independently hydrogen, an aliphatic group, an aromatic group, a combined aliphatic and aromatic group, or one of R.sub.9 and R.sub.10 form a double bond with L.sub.2; R.sub.11 and R.sub.12 are each an aliphatic group, an aromatic group, or a combined aliphatic and aromatic group; L.sub.2 is an aliphatic linking group, an aromatic linking group, or a combined aliphatic and aromatic linking group; A is P or As; and p is 0 or 1.

Histone deacetylase inhibitors and uses thereof are provided that have the general formula: ##STR00001## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, M and L have the definitions as described herein.

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.

Compounds that may be used to inhibit histone deacetylase having the formula Z-Q-L-M or Z-L-M wherein M is a substituent capable of complexing with a deacetylase catalytic site and/or a metal ion; L is a substituent providing between 0 10 atoms separation between the M substituent and the remainder of the compound; and Z and Q are as defined herein.

Compounds that may be used to inhibit histone deacetylase having the formula Z-Q-L-M or Z-L-M wherein M is a substituent capable of complexing with a deacetylase catalytic site and/or a metal ion; L is a substituent providing between 0-10 atoms separation between the M substituent and the remainder of the compound; and Z and Q are as defined herein.