[C:1]1([CH2:7][O:8][C:9]([NH:11][C@H](C(O)=O)CC(C)C)=[O:10])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.C[N:21]1[CH2:26][CH2:25][O:24]CC1.[CH2:27](OC(Cl)=O)[CH:28]([CH3:30])[CH3:29].N.CO>C(Cl)Cl>[C:1]1([CH2:7][O:8][C:9]([NH:11][C:25](=[O:24])[C@H:26]([CH2:27][CH:28]([CH3:30])[CH3:29])[NH2:21])=[O:10])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1To a solution of N-[(phenylmethoxy)carbonyl]-L-leucine (3 g., 11.3 mmol.) in 60 mL of methylene chloride at -20° under argon was added N-methyl -morpholine (1.24 mL, 11.3 mmol.) followed by isobutylchloroformate (1.47 mL, 11.3 mmol.). The resulting suspension was stirred at -20° C. for 15 minutes at which time a solution of ammonia/methanol (about 5.6M, 20 mL, 113 mmol.) was added. After 30 minutes at -20° C., the reaction was quenched with water and warmed to room temperature. The layers were separated and the aqueous layer was extracted with methylene chloride (2×). The combined organic extracts were dried (MgSO4) and evaporated to give 2.82 g. of the title A compound.
読み込み中…
