Lithium iodide → 3-(Ethoxycarbonyl)-1-benzyl-1,2-dihydro-2-oxopyridine-4-carboxylic acid

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Reaction Steps

A solution of 1-benzyl-2-oxo-1,2-dihydro-pyridine-3,4-dicarboxylic acid 3-ethyl ester 4-methyl ester (4.1 g, 13 mmol) in 10 mL of pyridine was added to a refluxing mixture of LiI (7.0 g, 52 mmol) and 50 mL of pyridine. The resulting mixture was refluxed for 1 h. After the mixture was cooled to r.t., solvent was evaporated in vacuo. The residue was taken up in water (150 mL) and acidified to pH about 2 with 6M HCl. The resulting suspension was extracted several times with CHCl3, and the organic layers were combined and dried over MgSO4. After solvent was evaporated in vacuo, the crude product was chromatographed (100% EtOAc) to give 1.8 g of the title compound as a yellow solid. 1H NMR (CDCl3, 200 MHz): δ=7.20-7.45 (m, 6H), 6.61 (d, 1H, J=7.0 Hz), 5.16 (s, 2H), 4.41 (q, 2H, J=7.4 Hz), 1.37 (t, 3H, J=6.2 Hz).

Provenance & Evidence