To a solution of 6.28 g (15.3 mmol) 4-(5-methylcarbamoyl-4-o-tolyl-pyridin-2-yl)-piperazine-1-carboxylic acid tert-butyl ester in 250 ml tetrahydrofuran 20 ml of a 1 M solution (20 mmol) of potassium hexamethyldisilazide in tetrahydrofuran were added at 0° C. After 30 min, 2.81 ml (15.3 mmol) 3,5-bis(trifluoromethyl)benzyl bromide were added dropwise. The reaction mixture was allowed to warm to room temperature over night. Addition of water and 1 M aqueous sodium hydroxide solution was followed by extraction with three portions of ethyl acetate. The combined organic extracts were dried with sodium sulfate and concentrated. Flash column chromatography gave 6.89 g (70.8%) of the parent compound as a white solid.
