Methanol → 7-bromo-4-fluoro-2-methoxy-9-(2-methoxyethylidene)-9H-xanthene
Reaction equation
[Br:1][C:2]1[CH:15]=[C:14]2[C:5]([O:6][C:7]3[C:8]([F:21])=[CH:9][C:10]([O:19][CH3:20])=[CH:11][C:12]=3[C:13]2([CH:17]=[CH2:18])O)=[CH:4][CH:3]=1.[CH3:22][OH:23].S(=O)(=O)(O)O>>[Br:1][C:2]1[CH:15]=[C:14]2[C:5]([O:6][C:7]3[C:8]([F:21])=[CH:9][C:10]([O:19][CH3:20])=[CH:11][C:12]=3[C:13]2=[CH:17][CH2:18][O:23][CH3:22])=[CH:4][CH:3]=1Participants
4
Conditions
- Temperature
- 55 °C
Procedure
To a 250 mL of RBF were added 7-bromo-4-fluoro-2-methoxy-9-vinyl-9H-xanthen-9-ol (8.69 g, 24.75 mmol), methanol (100 mL, 2475 mmol) and sulfuric acid (0.2M in water) (12.4 mL, 2.48 mmol). The mixture was heated to 55° C. for 25 min. The solvent was removed and the residue was diluted with EtOAc. The organic layer was washed by saturated aqueous NaHCO3. The aqueous layer was further extracted with EtOAc. The organic layers were combined and washed with brine, dried over magnesium sulfate, filtered and concentrated in vacuo to give the crude material as an oil. The crude product was purified by 35% to 50% to 75% to 100% DCM in Heptane to yield 7-bromo-4-fluoro-2-methoxy-9-(2-methoxyethylidene)-9H-xanthene (3.87 g, 10.60 mmol).