Bromine → (2R)-4-(5-Bromo-3-trifluoromethyl-pyridin-2-yl)-2-methyl-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

Bromine (1.52 mL, 29.7 mmol, Aldrich) was added dropwise over a period of 5 min to a solution (2R)-2-methyl-4-(3-trifluoromethyl-pyridin-2-yl)-piperazine-1-carboxylic acid tert-butyl ester from step (b) above (9.34 g, 27 mmol) in dichloromethane (100 mL) with stirring at room temperature. The mixture was stirred at room temperature for 30 min, the solvent was removed in vacuo and the residue was dissolved in EtOAc (200 mL). The solution was washed with sat. NaHCO3 (50 mL) and brine (50 mL), dried over Na2SO4, and filtered. The filtrate was evaporated in vacuo and the residue was purified by silica gel column chromatography, eluting with 10% EtOAc/hexane to give the title compound as a gum. MS (ESI, pos. ion) m/e: 426 (M+1).

Provenance & Evidence