1-(4-BROMO-2-THIENYL)ETHAN-1-ONE

88-15-3

7209-11-2

General procedure for the synthesis of 4-bromo-2-acetylthiophene from 2-acetylthiophene: In a 250 mL single-necked round-bottomed flask, 2-acetylthiophene (3.00 g, 23.81 mmol), anhydrous aluminum chloride (9.53 g, 71.43 mmol), and carbon tetrachloride (80 mL) were added, and the mixture was cooled to -40 °C. After 10 min, a slow dropwise addition of bromine ( 3.81 g, 23.81 mmol) in carbon tetrachloride (20 mL) was added slowly and stirred at room temperature for 0.5 h after completion of the addition. After 12 hours of reaction, TLC monitoring showed complete consumption of the feedstock. The reaction mixture was carefully poured into a mixture of saturated sodium hydroxide solution and crushed ice and extracted with ethyl acetate (75 mL x 3). The organic phases were combined, washed twice with saturated brine and dried over anhydrous magnesium sulfate. Purification by column chromatography (petroleum ether:ethyl acetate = 500:1) gave a pale yellow oily liquid product (2.74 g) in 72.6% yield.