Phosphoric Acid → 7-Bromo-1-benzofuran

関与物質

反応条件

反応手順

A suspension of potassium carbonate (50.0 g, 362 mmol) in 100 ml of DMF was added sequentially with 2-bromophenol (20.6 g, 120 mmol) and bromoacetaldehyde dimethyl acetal (20.2 g, 120 mmol) and stirred at 95° C. for 15 hours. The reaction solution was concentrated, liquid separation was carried out with ethyl acetate-water, the organic layer was sequentially washed with an aqueous solution of 1M-sodium hydroxide and saturated sodium chloride water, and dried with anhydrous magnesium sulfate. The residue obtained by concentration was dissolved in 200 ml of chlorobenzene, added at room temperature to a solution comprising diphosphorus pentoxide (8.07 g, 56.8 mmol) and 85% phosphoric acid (27 ml), which was stirred at 95° C. for 15 hours. After cooling to room temperature, the mixture was poured over ice water, stirred, and then extracted with dichloromethane. The organic layer was washed with saturated sodium chloride water and dried with anhydrous magnesium sulfate. The residue obtained by concentration was purified by silica gel chromatography (100% hexane) to obtain an oily product (10.4 g, 47%).

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