The general procedure for the synthesis of methyl 5-iodo-2-oxo-1,2-dihydropyridine-3-carboxylate from methyl 2-oxo-1,2-dihydro-3-pyridinecarboxylate was as follows: methyl 2-hydroxynicotinate (20 g) was dissolved in dichloromethane (500 mL) at room temperature, followed by the addition of N-iodosuccinimide (NIS, 38 g). The reaction mixture was heated to reflux for 16 hours. Upon completion of the reaction, the solvent was removed by evaporation. Ethyl acetate (200 mL) was added to the residue and heated under reflux conditions for 2 hours. The reaction mixture was cooled and the insoluble solid was collected by filtration to afford the target product methyl 2-hydroxy-5-iodonicotinate (30 g, 81% yield) as a white solid. The product was characterized by 1H NMR (300 MHz, CDCl3): δ 3.97 (s, 3H), 8.33 (brs, 1H), 8.43 (d, J=2.4Hz, 1H).
