1-(5-hydroxy-1-benzofuran-2-yl)ethanone

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 1-(5-hydroxy-1-benzofuran-2-yl)ethanone (2.40 g, 13.7 mmol) in anhydrous DMF (1 mL) were added 4-ethoxybenzyl chloride (2.81 g, 16.5 mmol) and potassium carbonate (3.78 g, 27.4 mmol) and the mixture was stirred at 50° C. overnight. Saturated brine was added thereto, and the mixture was extracted three times with ethyl acetate. The extract was washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure to give 1-{5-[(4-ethoxybenzyl)oxy]-1-benzofuran-2-yl}ethanone (6.95 g). This was directly used for the next reaction. the mixture was extracted three times with ethyl acetate The extract was washed with saturated brine dried over anhydrous magnesium sulfate The solvent was evaporated under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 1-(5-hydroxy-1-benzofuran-2-yl)ethanone (1.15 g, 6.53 mmol) in DMF (10 mL) were added tert-butyldimethylchlorosilane (1.07 g, 7.18 mmol) and imidazole (666 mg, 9.80 mmol), and the mixture was stirred at room temperature overnight. To the reaction mixture was added brine, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (hexane:ethyl acetate=19:1 to 7:3) to give the title compound (1.76 g, yield 98%). the mixture was extracted with ethyl acetate The extract was washed with saturated brine dried over anhydrous magnesium sulfate The solvent was evaporated under reduced pressure the obtained residue was purified by silica gel column chromatography (hexane:ethyl acetate=19:1 to 7:3)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Using 1-(5-hydroxy-1-benzofuran-2-yl)ethanone (1.15 g, 6.53 mmol), DMF (10 mL), tert-butyldimethylchlorosilane (1.07 g, 7.18 mmol) and imidazole (666 mg, 9.80 mmol), an operation in the same manner as in Reference Example 16 was performed to give the title compound (1.76 g, yield 98%).