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Example 1 Synthesis of 1-bromo-3-methylbutan-2-one: (1) Bromine (12.9 mL, 250 mmol) was added slowly and dropwise to an ethanol (EtOH, 250 mL) solution of 3-methyl-2-butanone (25.8 g, 300 mmol) under ice bath cooling conditions. The reaction mixture was stirred continuously for 2 h in an ice bath. After completion of the reaction, it was diluted by adding petroleum ether (600 mL). The organic phase was separated and washed twice with distilled water. The combined aqueous phases were back-extracted twice with petroleum ether. All organic phases were combined and washed twice each with cold sodium carbonate solution and saturated saline in that order. The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure at room temperature to afford the target product 1-bromo-3-methylbutan-2-one in 50% yield.

[1] Patent: US5910506, 1999, A
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