Hydrochloric Acid → 8-bromo-2-morpholino-4-oxo-4H-chromene-6-carboxylic acid

Participants

Reaction Steps

NaOH 2N (40.7 mL, 81.48 mmol) was added to methyl 8-bromo-2-morpholino-4-oxo-4H-chromene-6-carboxylate (10 g, 27.2 mmol) in a mixture of methanol (225 mL) and DCM (75 mL). The slurry was stirred at room temperature for 16 h. The solvents were evaporated, water (150 mL) was added to the slurry, the solution was cooled down to 0° C. and HCl 6N (15 mL, 89.6 mmol) solution was added dropwise to the reaction mixture until pH ˜3.4. The formed solid was collected by filtration, washed with water (3×50 mL), then toluene (3×50 mL) followed by Diethyl ether (3×50 mL), dried at 55° C. under vacuum over P2O5 to afford 8-bromo-2-morpholino-4-oxo-4H-chromene-6-carboxylic acid (9.47 g, 98%) as a beige solid. The crude product was used without further purification.

Provenance & Evidence