A solution of 2-(2-aminoethyl)nitrobenzene (8.00 g, 48.1 mmol) and 1-t-butoxycarbonyl-4-piperidinone (9.59 g, 48.1 mmol) in methanol (100 mL) was brought to pH 5 by the addition of acetic acid. Sodium cyanoborohydride (4.53 g, 72.2 mmol) was added and the reaction stirred for 3 h. Methanol was removed in vacuo, and the residue partitioned between ethyl acetate and saturated sodium bicarbonate solution. The organic phase was washed with saturated brine and dried over sodium sulfate. The title compound was obtained as an oil (19.27 g). MS: m/z=350 (M+1).
