Hydrochloric Acid → 1-[4-Methoxy-5-(5,6,7,8-tetrahydronaphthalen-2-yl)thiophen-3-yl]ethanone

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Reaction Steps

To 3.51 g of 4-methoxy-5-(5,6,7,8-tetrahydronaphthalen-2-yl)thiophene-3-carbonitrile in diethyl ether (45 ml) cooled with water, 43.3 ml of methylmagnesium bromide (3.0 M diethyl ether solution) was added dropwise at room temperature over 5 minutes (exothemically). The reaction mixture was allowed to react at room temperature for 3 days and poured into 30 ml of concentrated hydrochloric acid diluted with 300 ml of ice-cold water and stirred at room temperature for 1 hour then on a water bath at 35° C. for 1 hour. After addition of 200 ml of ethyl acetate, the reaction mixture was allowed to separate, and the organic layer was collected. The aqueous layer was extracted with 100 ml of ethyl acetate three times, and the extracts were combined with the organic layer. The organic layer was washed with saturated aqueous sodium chloride, 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→1/15) to obtain 2.44 g of the desired product (yield 65%).

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