Bobcat339 hydrochloride is a potent and selective inhibitor of DNA methyltransferase 1 (DNMT1), a key enzyme involved in epigenetic regulation through DNA methylation. It is primarily used in epigenetics and molecular biology research to investigate the role of DNMT1 in gene expression, cellular processes, and disease mechanisms, including cancer, inflammation, fibrosis, and neurological disorders. Unlike non-selective DNMT inhibitors, Bobcat339 specifically targets DNMT1, enabling precise studies on maintenance DNA methylation without broadly affecting DNA synthesis or other methyltransferases. It is also employed in preclinical models to explore therapeutic potential for conditions driven by aberrant DNA methylation, such as tumors and autoimmune diseases.