Hydrochloric Acid → (R)-1-methyl-2-[4-(2-methoxyphenyl)-piperazinyl]ethylamine

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Reaction Steps

The above mentioned (R)-{1-methyl-2-[4-(2-methoxyphenyl)-piperazin-1-yl]-2-amino-propan-2-1-one hydrochloride (5.90 g, 19.7 mmol) was dissolved in anhydrous tetrahydrofuran (60 mL) at room temperature. Triethylamine (6.3 mL, 45 mmol) was added, followed by dropwise addition of a 1M solution of borane in tetrahydrofuran (77.5 mL, 45 mmol). The resulting mixture was refluxed for 18 hours. After cooling the reaction mixture to room temperature, ethyl acetate (60 mL) and 2N aqueous HCl were added and the resulting mixture was stirred at room temperature for one hour. The layers were separated and the aqueous layer was made basic by careful addition of 50% aqueous NaOH. The resulting basic mixture was extracted with three 50 mL portions of ethyl acetate. The combined organic layers were washed with brine (50 mL) and dried over anhydrous sodium sulfate. Filtration and concentration on a rotary evaporator yielded 4.62 g (94%) of the desired of 2-[4-(2-methoxyphenyl)-piperazin-1-yl]-ethylamine as a colorless oil which was used without further purification.

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