Hydrogen chloride (4M in dioxane) (2.4 mL, 9.6 mmol) was added to a stirred solution of tert-butyl 2-(6-(methoxycarbonyl)-2-morpholino-4-oxo-4H-chromen-8-yl)pyrrolidine-1-carboxylate (440 mg, 0.96 mmol) dissolved in dioxane (3 mL) and DCM (3 mL) at room temperature and the reaction mixture stirred for 4 h. The solvents were evaporated and the residue azeotroped twice with MeCN and dried under vacuum at 50° C. The remaining solid was then extracted with DCM. The DCM was dried over MgSO4 and concentrated to afford methyl 2-morpholino-4-oxo-8-(pyrrolidin-2-yl)-4H-chromene-6-carboxylate (286 mg, 83%) as a pale beige solid.
