1,2-Dichloroethane → L-Leucine

Participants

Reaction Steps

L-Lysine, N-ε-(carbobenzoxy)-[N-α-[N-[4-[4-(2-methyl-1H-imidazol-1-yl) -butyl]phenyl]acetyl]-L-(O-benzyl)-seryl]-, (0.46 g. 6.46 mmol), HOBT (0.089 g, 6.78 mmol), and EDC (0.13 g, 6.78 mmol) were dissolved in 15 mL of DMF. The solution was stirred for 40 minutes at room temperature. L-Leucine methyl ester (0.13 g, 7.11 mmol) was dissolved in 5 mL of DMF containing N-methylmorpholine (0.20 g, 1.94 mol) and then added to this solution. The reaction mixture was stirred overnight at room temperature, and the DMF was removed in vacuo. The concentrated residue was brought up in 150 mL of dichloromethane, and the organic phase was washed with saturated aqueous NaHCO3 (2×100 mL), brine (2×100 mL), dried over MgSO4, filtered and concentrated. The concentrated residue was purified by silica gel flash column chromatography eluting with 5% methanol in methylene chloride to give 0.27 g (49.8%) of L-leucine, N-[N2 -[N-[[4-[4-(2-methyl-1H-imidazol-1-yl)butyl]phenyl]acetyl]-L-(O-benzyl)-seryl]-N-ε-(carbobenzoxy)-L-lysyl]-, methyl ester as a white solid. FAB-MS m/z=839 (M+H). HRMS: calcd for C47H63N6O8 (M+H) 839.4707, found: 839.4706.

Provenance & Evidence