Methanol → Methyl 2-(6-hydroxy-1-benzofuran-3-yl)acetate

Temperature

60 °C

To a solution of (6-hydroxy-1-benzofuran-3-yl)acetic acid (20.0 g) in methanol (300 mL) was added concentrated sulfuric acid (7 mL), and the mixture was stirred at 60° C. for 4 hr. After concentration, to the residue were added ethyl acetate (400 mL) and saturated aqueous sodium hydrogen carbonate (400 mL), and an extraction operation was performed. The aqueous layer was extracted twice with ethyl acetate (200 mL), and the organic layer was washed with saturated brine (400 mL), dried over anhydrous sodium sulfate, and concentrated. The residue was dissolved in toluene (60 mL) at 60° C., allowed to cool to room temperature, and seed crystal was added. Normal heptane (120 mL) was added, and the mixture was stirred at room temperature for 16 hr and at 0° C. for 1 hr. The precipitated crystals were collected by filtration, and dried at 50° C. to give the title compound (19.6 g) as white crystals.

1. concentrationAfter concentration
2. additionto the residue were added ethyl acetate (400 mL) and saturated aqueous sodium hydrogen carbonate (400 mL)
3. extractionThe aqueous layer was extracted twice with ethyl acetate (200 mL)
4. washthe organic layer was washed with saturated brine (400 mL)
5. dry with materialdried over anhydrous sodium sulfate
6. concentrationconcentrated
7. dissolutionThe residue was dissolved in toluene (60 mL) at 60° C.
8. temperatureto cool to room temperature
9. additionseed crystal was added
10. additionNormal heptane (120 mL) was added
11. stirringthe mixture was stirred at room temperature for 16 hr and at 0° C. for 1 hr
12. filtrationThe precipitated crystals were collected by filtration
13. customdried at 50° C.

ORD record

ord-992b646fee524eeb83f91f9a863e7827

Source dataset

uspto-grants-2015_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08952185B2