Water → N-tert-butoxycarbonyl-N-cyclopropyl-N'-isopropyl-ethane-1,2-diamine

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Reaction Steps

3.9 mL (13 mmol) of titanium isopropoxide and 2 g (10 mmol) of (tert-butoxycarbonyl-isopropyl-amino)-acetaldehyde (prepared according to the method described by Kato, Shiro et al., J. Chem. Soc. Perkin Trans. 1, 1997, 21, 3219-26) are added to a solution of 1.71 g (30 mmol) of cyclopropylamine in 15 mL of anhydrous methanol. The solution is stirred for 5 hours at room temperature then 454 mg (12 mmol) of sodium borohydride is added. Stirring is continued for a further 2 hours then 2 mL of water is added. The reaction mixture is filtered then the solvents are evaporated. The residue is purified by chromatography on silica (eluent dichloromethane/methanol 98/2 then 95/5) to give 852 mg (35%) of N-tert-butoxycarbonyl-N-cyclopropyl-N′-isopropyl-ethane-1,2-diamine in the form of a colourless oil.

Provenance & Evidence