Sodium Sulfite → 5-amino-4-bromo-2,2,6,7-tetramethyl-1-benzofuran-3(2H)-one

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Reaction Conditions

Reaction Steps

Tetrabutylammonium tribromide (31.0 g, 64.2 mmol) was added to a tetrahydrofuran solution (200 mL) containing 5-amino-2,2,6,7-tetramethyl-1-benzofuran-3(2H)-one (6.59 g, 32.1 mmol) synthesized in Reference Example 20 at 0° C., and the mixture was stirred at 0° C. for 2 hours. To the mixture, a saturated sodium sulfite aqueous solution was added, and extraction was performed using ethyl acetate. The extract was dried using anhydrous magnesium sulfate. After that, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (hexane-ethyl acetate 98:2 to 85:15) to give 6.60 g of the title compound (yield: 72%).

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