Histone deacetylase inhibitor and process for producing the same

A compound represented by formula (1)

• wherein
• R11, R21, R31, and R41 independently represent a hydrogen or methyl group;
• R22, R23, R32, R33, R42, and R43 independently represent any one of hydrogen, a linear alkyl group comprising 1 to 6 carbons, a linear alkyl group comprising 1 to 6 carbons to which a non-aromatic cyclic alkyl group or a substituted or unsubstituted aromatic ring is attached, a non-aromatic cyclic alkyl group, or a non-aromatic cyclic alkyl group to which a non-aromatic cyclic alkyl group or a substituted or unsubstituted aromatic ring is attached;
• R21 and R22, R22 and R23, R31 and R32, R32 and R33, R41 and R42, and R42 and R43 may independently represent a non-cyclic structure without bonding to each other, or may independently represent a cyclic structure by bonding to each other through a linear alkylene group having a chain length of 1 to 5 carbons, a linear alkylene chain having a chain length of 1 to 5 carbons and carrying a branched chain of 1 to 6 carbon atoms, or a linear alkylene chain having a chain length of 1 to 5 carbons and carrying a cyclic structure of 1 to 6 carbon atoms;
• n can be selected from a range of numbers that enable the compound to have HDAC inhibitory activity;
• and
• X represents a structural component having a structure that can coordinate with the zinc positioned at the active center of histone deacetylase.