反应详情

温度

50 °C

Trifluoromethanesulfonic anhydride (0.755 L, 4487 mmol) was added to a stirred solution of methyl 3-bromo-4-hydroxy-5-(3-morpholino-3-oxopropanoyl)benzoate (433 g, 1122 mmol, pooled material from several batches) dissolved in 1,2-dichloroethane (1 L) at room temperature under nitrogen (exotherm). The resulting solution was stirred at 50° C. overnight. The mixture was partially evaporated, and the residue was diluted with MeOH (1.6 L) at 0° C. (exotherm) and stirred for 1 h at RT. The solvent was evaporated again and the residue was diluted in DCM, quenched with a saturated aqueous solution of sodium carbonate and extracted with DCM. The combined organic phases were washed with brine, dried over MgSO4 and concentrated to afford the crude product. The crude was triturated under MTBE (2×), EtAc (1×) and MTBE (1×). The solid was dried to afford methyl 8-bromo-2-morpholino-4-oxo-4H-chromene-6-carboxylate (208 g, 50%) as a beige solid. Mass Spectrum: m/z [M+H]+=370.

1. customThe mixture was partially evaporated
2. additionthe residue was diluted with MeOH (1.6 L) at 0° C. (exotherm)
3. stirringstirred for 1 h at RT
4. customThe solvent was evaporated again
5. additionthe residue was diluted in DCM
6. customquenched with a saturated aqueous solution of sodium carbonate
7. extractionextracted with DCM
8. washThe combined organic phases were washed with brine
9. dry with materialdried over MgSO4
10. concentrationconcentrated
11. customto afford the crude product
12. customThe crude was triturated under MTBE (2×)
13. customThe solid was dried