How is 7-amino-1-cyclopropyl-3-ethyl-2,4-dioxo-pyrido[2,3-d]pyrimidine-6-carboxamide (CAS: 142557-61-7) typically synthesized?

7-Amino-1-cyclopropyl-3-ethyl-2,4-dioxo-pyrido[2,3-d]pyrimidine-6-carboxamide can be synthesized via amidation of an appropriately functionalized pyridine derivative with an amine. Commonly, a carbodiimide such as EDCl or DCC is used as a coupling agent, followed by a base like DIPEA. The reaction typically occurs in solvents like DMF or DCM at room temperature, achieving good yields with high selectivity.