Boron tribromide → 1-[4-Hydroxy-5-(5,6,7,8-tetrahydronaphthalen-2-yl)thiophen-3-yl]ethanone

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Reaction Steps

To 2.4 g of 1-[4-methoxy-5-(5,6,7,8-tetrahydronaphthalen-2-yl)thiophen-3-yl]ethanone in chloroform (25 ml) cooled with ice, 9.4 ml of boron tribromide (1.0 M dichloromethane solution) was added dropwise, and then the reaction mixture was allowed to react for 1.5 hours. The reaction mixture was poured into 300 ml of ice-cold water and extracted with 250 ml of chloroform. The aqueous layer was extracted with 100 ml of chloroform once, and the extract was combined with the previously chloroform extract, washed with 150 ml of saturated aqueous sodium chloride twice, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The resulting residue (dark brown oil) was purified by silica gel column chromatography (eluent: ethyl acetate/hexane=1/20), and the resulting solid was washed with hexane to obtain 1.05 g of the desired product (yield 45%).

Provenance & Evidence