Hydrochloric Acid → Benzyl N-(2-aminoethyl)carbamate hydrochloride

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Reaction Steps

Under an atmosphere of dry argon, 24.3 g (0.128 mol) of N-CBZ-aminoacetonitrile (1e) was dissolved in anhydrous tetrahydrofuran (32 ml). The solution was stirred and 64 ml of borane-methylsulfide complex (2M in tetrahydrofuran) was added via syringe. The mixture was heated to reflux and stirred overnight. The mixture was cooled with an ice bath as 5 ml of water was added slowly, with vigorous stirring. The stirring was continued for ca. 5 minutes, then 75 ml of 6M HCl was slowly added. The mixture was stirred for 1 hour, then the excess tetrahydrofuran and dimethyl sulfide was removed in vacuo . The aqueous residue was extracted with ether (2×50 ml). The ether extracts were then discarded. The pH of the aqueous residue was raised to 11 by adding concentrated NH4OH. The resulting aqueous solution was extracted with ethyl acetate (3×100 ml) and the ethyl acetate extracts were combined and washed with brine (50 ml). After drying over anhydrous magnesium sulfate, the solution was filtered and concentrated in vacuo. The resulting oil was dissolved in 30 ml of anhydrous methanol, treated with cold methanolic HCl and concentrated in vacuo to produce a solid. The solid was triturated with ether and collected by filtration to give 15.1 g (51% yield) of N-CBZ-ethylenediamine hydrochloride (1f) as a white powder. 1H NMR(D2O) δ 3.15(m, 2H), 3.46(m, 2H), 5.14(s, 2H), 7.46(bs, 5H); 13C NMR (D2O) δ 41.1, 42.6, 70.4, 131.0, 131.3, 131.7, 132.0, 139.4, 161.7.

Provenance & Evidence