Enamine cyclization

Bond-Formation Sequence and Process Improvement for 3-Bromo-6-alkyl-1,6-naphthyridin-5(6H)-ones: From Late-Stage N-Alkylation to Enamine Cyclization with Primary Amines

In 2024, Carr et al. reported in Organic Process Research & Development a scalable synthetic route to 3-bromo-6-alkyl-1,6-naphthyridin-5(6H)-ones. In this class of compounds, the lactam carbonyl is located at the 5-position and the alkyl group is attached to the nitrogen atom at the 6-position. ...