Diisopropylethylamine → 8-bromo-N,N-dimethyl-2-morpholino-4-oxo-4H-chromene-6-carboxamide

Participants

Reaction Steps

TSTU (6.55 g, 21.74 mmol) was added to a stirred solution of 8-bromo-2-morpholino-4-oxo-4H-chromene-6-carboxylic acid (7 g, 19.77 mmol) and DIPEA (3.79 mL, 21.74 mmol) dissolved in DCM (100 mL) under nitrogen. The resulting suspension was stirred at room temperature for 4 h. More TSTU (6.55 g, 21.74 mmol) and DIPEA (3.79 mL, 21.74 mmol) were added and stirring was pursued for a further 16 h. The reaction mixture was quenched with a saturated aqueous solution of sodium hydrogencarbonate and extracted with DCM and a little MeOH. The combined organic phases were dried over MgSO4, concentrated and purified by flash chromatography on silica gel eluting with 3 to 5% MeOH in DCM. The solvent was evaporated to dryness to afford 8-bromo-N,N-dimethyl-2-morpholino-4-oxo-4H-chromene-6-carboxamide (7.70 g, 102%) as a beige solid. Mass Spectrum: m/z [M+H]+=381.

Provenance & Evidence