p-Toluenesulfonic acid → Ethyl 4-hydroxy-8-iodoquinoline-3-carboxylate

Participants

Reaction Steps

In a 2-neck round bottomed flask (250 mL), phenylether (60 mL) was put to reflux on a heating mantel. When it started boiling, p-toluenesulfonic acid (0.140 g) was added. 2-[(2-iodo-phenylamino)-methylene]-malonic acid diethyl ester was dissolved in phenylether (20 mL) and the mixture was poured into the boiling solvent. The mixture was refluxed for 3 h. The crude was transferred to a bequer and cooled to room temperature. Hexanes (600 mL) were added and a precipitate was observed. The mixture was stirred for 5 min, followed by filtration of the solid and thorough wash with hexanes to afford 8-iodo-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid ethyl ester as a grayish solid (2 g, 46%). 1H NMR (DMSO-d6, 400 MHz) δ 1.43 (t, 3H), 4.39 (q, 2H), 7.36 (t, 1H), 8.32 (d, 1H), 8.37 (d, 1H), 8.63 (s, 1H), 11.4 (s, 1H). Exact mass calculated for C12H10INO3 342.97, found 343.9 (MH+).

Provenance & Evidence