The general procedure for the synthesis of 1-(5-bromothiophen-3-yl)ethanone from 3-acetylthiophene is as follows: to a solution of acetic acid (50 mL) containing 3-acetylthiophene (2.52 g, 20 mmol, 1.0 eq.), sodium acetate (2.46 g, 30 mmol, 1.5 eq.) and bromine (3.2 g, 20 mmol, 1.0 eq.) are added sequentially, the bromine The addition of bromine was controlled to be completed within 30 minutes. The reaction mixture was stirred at room temperature overnight. Subsequently, water (150 mL) was added to the reaction system and stirring was continued for 2 hours. The resulting solid product was collected by filtration, washed sequentially with water (10 mL) and petroleum ether (20 mL), and dried to afford the target compound 1-(5-bromothiophen-3-yl)ethanone (8i-2) as a brown solid (1.52 g, 37% yield).
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