Acetic Acid → 2-[2-(3,4-Difluorophenyl)ethylamino]ethyl carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of tert-butyl-N-(2-aminoethyl)carbamate (718 mg, 4.5 mmol) in MeOH (40 mL) at 0° C., under nitrogen, was added (3,4-difluorophenyl)acetaldehyde (0.7 g, 4.5 mmol) in MeOH (10 mL), acetic acid (0.78 mL, 13.5 mmol) and sodium cyanoborohydride (564 mg, 9.0 mmol). After stirring at 0° C. for 15 min the cooling bath was removed and the mixture stirred at room temperature for 3 h. Saturated K2CO3 solution (50 mL) was added and the mixture stirred for a further 15 min. The solvents were removed in vacuo and the residue partitioned between water (50 mL) and EtOAc (2×50 mL). The combined organic layers were dried (Na2SO4), and evaporated. The residue was chromatographed on silica gel, eluting with CH2Cl2 :MeOH:NH3 (90:10:1) to give the amine (473 mg, 35%) as a yellow oil. 1H NMR (250 MHz, CDCl3) δ 1.44 (9H, s), 2.72-2.78 (4H, m), 2.83-2.90 (2H, m), 3.18-3.28 (2H, m), 4.87 (1H, br s), 6.87-7.13 (3H, m). MS (ES+) (301, M+1).

Provenance & Evidence