Cell Penetrant Inhibitors of the KDM4 and KDM5 Families of Histone Lysine Demethylases. 2. Pyrido[3,4‑<i>d</i>]pyrimidin-4(3<i>H</i>)‑one Derivatives

Following the discovery of cell penetrant pyridine-4-carboxylate inhibitors of the KDM4 (JMJD2) and KDM5 (JARID1) families of histone lysine demethylases (e.g., 1), further optimization led to the identification of non-carboxylate inhibitors derived from pyrido­[3,4-d]­pyrimidin-4­(3H)-one. A number of exemplars such as compound 41 possess interesting activity profiles in KDM4C and KDM5C biochemical and target-specific, cellular mechanistic assays.