This invention relates to generally inhibiting histone deacetylase (“HDAC”) enzymes (e.g., HDAC1, HDAC2, and HDAC3) using compounds of formula (I), wherein the substituents are as defined herein.L'invention concerne des composés et des procédés pour inhiber des enzymes désacétylases d'histone ("HDAC") (par exemple, HDACl, HDAC2 et HDAC3).