Entinostat is a benzamide formed by the condensation of the carboxy group of a pyridin-3-ylmethyl carbamate derivative of p-(aminomethyl)benzoic acid with an amino group of benzene-1,2-diamine. It inhibits histone deacetylase isoforms 1 and 3 (HDAC1 and HDAC3). It functions as an EC 3.5.1.98 histone deacetylase inhibitor, an antineoplastic agent, and an apoptosis inducer. It belongs to pyridines, carbamate esters, substituted anilines, primary amino compounds, and benzamides. It is functionally related to 1,2-phenylenediamine.