Triethylamine → 4-(2-Bromo-4-fluorobenzoyl)piperazin-2-one

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Reaction Steps

2-piperazinone (0.601 g, 6 mmol, commercially available from e.g. Sigma-Aldrich) was dissolved in dichloromethane (DCM) (30 mL), and to this was added triethylamine (1.004 mL, 7.20 mmol). The solution was then cooled to 0° C. before 2-bromo-4-fluorobenzoyl chloride (1.567 g, 6.60 mmol, commercially available from e.g. Sigma-Aldrich, Apollo or Fluorochem) in dichloromethane (DCM) (5 mL) was added dropwise. The solution was stirred, under argon, for 30 minutes before the solvent was evaporated in vacuo. The remaining residue was then re-dissolved in DCM (40 mL) and washed with water (20 mL), a saturated solution of sodium bicarbonate (20 mL) and brine (20 mL), before being dried over anhydrous sodium sulphate. The sodium sulphate was then removed by filtration and the solvent was evaporated in vacuo. The remaining solid was then stirred in hexane (40 mL) at 55° C. for 30 minutes. The solid was then removed by filtration to yield the product in 1.625 g.

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