Iodoethane → methyl 8-bromo-2-(ethylthio)-4-oxo-4H-chromene-6-carboxylate

Participants

Reaction Steps

Iodoethane (37.1 mL, 463.51 mmol) was added in one portion to a stirred suspension of methyl 8-bromo-4-hydroxy-2-thioxo-2H-chromene-6-carboxylate (48.69 g, 154.5 mmol) and potassium carbonate (21.35 g, 154.50 mmol) in acetone (490 mL). The resulting suspension was stirred at reflux for 1 h under nitrogen in a flask equipped with a bleach trap. The reaction mixture was concentrated, the residue was diluted with DCM (980 mL)/water (490 mL). The phases were separated and the aqueous layer was extracted with DCM (490 mL). The combined organic phases were washed with brine, dried over MgSO4 and concentrated. The residue was triturated with petroleum ether, filtered and dried under vacuum to give methyl 8-bromo-2-(ethylthio)-4-oxo-4H-chromene-6-carboxylate (52.9 g, 100%) as a pale brown solid. Mass Spectrum: m/z [M+H]+=345

Provenance & Evidence