Hydrochloric Acid → tert-Butyl 4-(butylamino)piperidine-1-carboxylate

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Reaction Steps

A mixture of 1-(1,1-dimethylethoxycarbonyl)-4-piperidone (IX, 1.50 g) in methanol (15 ml) under nitrogen is cooled in an ice bath, treated with butylamine (X, 0.93 ml) and sodium cyanoborohydride (235 mg), adjusted to pH 5 with glacial acetic acid as determined on moistened pH test paper, and stirred at 20°-25° for 24 hrs during which additional sodium cyanoborohydride (115 mg) is added. The mixture is then adjusted to pH 3 using hydrochloric acid (3M) and concentrated under reduced pressure, the residue is diluted with water (20 ml) and extracted with ether (2×20 ml), and the organic phase is discarded. The aqueous phase is adjusted to pH 12 with potassium hydroxide, saturated with sodium chloride, and extracted with methylene chloride (3×25 ml). The combined organic phase is dried over sodium sulfate and concentrated under reduced pressure to give the title compound, Anal. Calcd for C14H28N2O2 : C=65.59, H=11.01, N=10.93, found: C=65.44, H=11.05, N=10.81.

Provenance & Evidence