Methyl iodide → 4-Benzyl-1-tert-butoxycarbonyl-2(S)-(2-methoxyethyl)piperazine

Participants

Reaction Conditions

Reaction Steps

A solution of 4-benzyl-1-tert-butoxycarbonyl-2(S)-(2-hydroxyethyl)piperazine (0.322 g, 1.00 mmol) in dry, degassed dimethylformamide (4 mL) was cooled under nitrogen to 0° C. Sodium hydride was added (0.052 g, 60% dispersion in oil, 1.30 mmol) followed by methyl iodide (0.88 mL, 1.41 mmol). After 3 h, the reaction was quenched with saturated ammonium chloride. The solvent was removed in vacuo and the residue partitioned between ethyl acetate and saturated sodium bicarbonate. The ethyl acetate was washed with water, saturated sodium chloride solution, and dried over magnesium sulfate. The crude product was chromatographed on silica gel with 40% ethyl acetate in hexane to obtain the title compound as a clear oil (280 mg). NMR (CD3OD, 300 MHz) δ 7.3 (5H, m), 4.19 (1H, m), 3.85 (1H, dm, J=13 Hz), 3.56 (1H, d, J=13 Hz), 3.16 (1H, d, J=13 Hz), 3.28 (2H, m, partially obscured by solvent), 3.23 (3H, s), 3.08 (1H, t, J=13 Hz), 2.80 (1H, d, J=11 Hz), 2.70 (1H, d, J=11 Hz), 2.03 (3H, m), 1.86, (1H, sextet, J=6 Hz), 1.45 (9H, s).

Provenance & Evidence