Leucine, N-carboxy-, N-benzyl ester, L- → Z-Leu-Leu methyl ester

Participants

Reaction Steps

N-Cbz-L-leucine (Chemical Dynamics) (1.32 g, 4.97 mmol), L-leucine methyl ester hydrochloride (Aldrich) (0.99 g, 5.47 mmol), 1-hydroxybenzotriazole (0.14 g, 1.0 mmol) and 1-(3-dimethylaminopropyl)-3ethylcarbodiimide hydrochloride (1.05 g, 5.47 mmol) were combined, dissolved in 25 nL of DMF and stirred at room temperature for 15 h. The solution was diluted with ethyl acetate (250 mL) and washed successively with water, 0.1 N HCl, saturated aqeous NaHCO3 and saturated brine, then dried (MgSO4), filtered, and concentrated. The residue was purified by flash chromatography on 230-400 mesh silica gel, eluting with 1:3 ethyl acetate hexanes, to give the title compound as a white solid (1.28 g, 66%). 1H NMR (400 MHz, CDCl3) δ 7.37-7.32 (m, 5H), 6.28 (d, 1H), 5.28 (m, 3H), 4.61-4.58 (m, 1H), 4.20 (m, 1H), 3.74 (s, 3H), 1.69-1.54 (m, 6H), 0.96-0.92 (m, 12H).

Provenance & Evidence