Aluminium lithium hydride → N-methyl-1-(propan-2-yl)piperidin-4-amine

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Reaction Steps

100 ml absolute diethyl ether were placed in a dry three-necked flask equipped with a condenser. 4.35 g LiAlH4 (6 equiv.) were added and the mixture was stirred at room temperature under an argon atmosphere. Carefully, 4.10 g (19.13 mmol) (1-isopropyl-piperidin-4-yl)-carbamic acid ethyl ester were added portionwise and the resulting mixture was refluxed for 7 h. Since the conversion was not complete, 1.00 g (≈1.4 equiv.) LiAlH4 was added and the mixture was refluxed for further 2 h. The reaction mixture was cooled and, carefully, 14 ml water were added dropwise over a 20-minute period. The mixture was diluted with 40 ml water and 50 ml diethyl ether. The phases were separated. The aqueous phase (suspension) was treated with a 10% NaOH-solution and washed twice with 100 ml diethyl ether. The organic phases were combined, dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was obtained as a colorless oil. Yield: 2.91 g MS (ES+): m/e=157.

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