N-Iodosuccinimide → Methyl 5-iodo-2-oxo-1,2-dihydropyridine-3-carboxylate

Participants

Reaction Steps

A solution containing 19.48 g of methyl 2-oxo-1,2-dihydro-3-pyridinecarboxylate and 36.15 g of N-iodosuccinimide in 500 ml of anhydrous methylene chloride is heated at reflux under a nitrogen atmosphere in the dark for 48 hours. The reaction mixture is concentrated to 150 ml under reduced pressure and the solid which forms is collected by filtration and washed with small portions of cold methylene chloride and benzene to give 16.59 g (47%) of methyl 5-iodo-2-oxo-1,2-dihydro-3-pyridinecarboxylate as a pale yellowish solid. This material is sufficiently pure for the next reaction; its properties upon recrystallization from ethyl acetate are as follows: m.p. 190°-192° C.; NMR (DMSO-d6, 300 MHz) delta 3.71 (s, 3H), 7.93 (d, 1H, J=2.26 Hz), 8.10 (d, 1H, J=2.26 Hz), IR (KBr) 2500-3050 (broad), 1725, 1630, 1585, 1475, 1425, 1320, 1260, 1235, 1180, 1150, 1105, 1065, 965, 875 and 800 cm-1 ; M/S (279, M+), 247, 127 and 93. Anal. Calcd. for C7H6INO3 : C, 30.13; H, 2.17; I, 45.48; N, 5.02. Found: C, 30.24; H, 2.22; I, 45.55: N, 4.87. The filtrate is evaporated and the residue dissolved in 500 ml of methylene chloride. The organic solution is extracted with a 10% sodium thiosulfate solution, washed with a saturated sodium chloride solution, and dried over anhydrous sodium sulfate. The solution is concentrated under reduced pressure and the residue triturated with ethyl acetate and filtered to yield an additional 5.49 g (15%) of methyl 5-iodo-2-oxo-1,2-dihydro-3-pyridinecarboxylate.

Provenance & Evidence