Abstract: Disclosed are 2-amino-7,8-dihydro-6H-pyrido[4,3-d]pyrimidin-5-one compounds, their stereoisomers, tautomers, pharmaceutically acceptable salts, and prodrugs thereof; compositions that include a pharmaceutically acceptable carrier and one or more of the 2-amino-7,8-dihydro-6H-pyrido[4,3-d]pyrimidin-5-one compounds, either alone or in combination with at least one additional therapeutic agent. Disclosed also are methods of using the 2-amino-7,8-dihydro-6H-pyrido[4,3-d]pyrimidin-5-one compounds, either alone or in combination with at least one additional therapeutic agent, in the prophylaxis or treatment of cellular proliferative, viral, autoimmune, cardiovascular, and central nervous system diseases.