Trifluoroacetic acid → 1-(6-Bromopyridin-3-yl)piperazine

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Reaction Steps

11.20 ml (150.77 mmol) of trifluoroacetic acid are slowly added to a suspension of 5.16 g (15.08 mmol) of 1,1-dimethylethyl 4-(6-bromo-3-pyridyl)-1-piperazinecarboxylate, obtained in step 7.2, in 70 ml of dichloromethane. Stirring is continued at room temperature for 16 hours. The reaction mixture is concentrated under reduced pressure, the residue is taken up in 40 ml of chloroform and 4 ml of aqueous sodium hydroxide solution (10M) are then slowly added. The aqueous phase is separated out and then extracted twice with chloroform. The organic phases are combined and are washed with saturated aqueous sodium chloride solution. The organic phase is dried over sodium sulfate and the filtrate is concentrated under reduced pressure. 5.16 g of product are thus obtained in the form of an orange-colored oil that crystallizes at room temperature. This product is used without further purification in the following step.

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