Of the three types of dihydropyridinones of α-enone structure, two types (1and2) are known1and utilized as synthetic or structural key substances. As for the last of them, 1,6-dihydro-3 (2H)-pyridinone (3), however, little is known of the chemistry of its flamework to data.2It is the only α-enone free from conjugation with nitrogen atom and has versatile functionalities with many reactive centers toward nucleophilic or electrophilic attacks. Then, we have investigated the chemistry of 1,6-dihydro-3(2H)-pyridinones and wish to report the preparation of ethyl 1,b-dihydro3(2∼)-pyridinone-l-carboxylate (3∼ R=CO2Et).