Benzyl [(1S)-1-(aminocarbonyl)-2,2-dimethylpropyl carbamate
To a solution of N-[(benzylaxy)carbonyl]-tert-leucine 3.7 g. 14 mmol) in DMF (80 mL)
were added ammonium chloride (900 mg. 17 mmol), triethylamine (5,9 ml, 42 mmol), HOBI (2.5 g, 18 mmol), and EDC (3.1 g. 18 mmol) at rt
After 17 h, the reaction mixture was quenched by addition of sat. aq. sodium bicarbonate (100 mL) and extracted with ethyl acetate (100 ml. x 3). The combined organic layers were washed with water (100 mL x 3), brine (50 mL), dried over sodium sulfate, filtered and concentrated in vacuo.
Residunya dimurnikan dengan kromatografi kolom pada silika gel yang dielusi dengan heksana/etil asetat (2/1-1/1) hingga menghasilkan 3,0 g (82%)
L-Tert-Leucinamide
To a solution of benzyl ((1S)-1-(aminocarbonyl)-2,2-dimethylpropyl carbamate (3.7 g. 14 mmol) in THF (40mL) was added 10% Pd/C (710 mg). The flask was evacuated and flushed with H₂ gas and this process was repeated three times. The flask was filled with H₂ gas (4 atm) and stirred for 3 h at rt. Then the reaction mixture was filtered through a pad of Celite and concentrated in vacuo to give the title compound as white solid (crude; 1.8 g).
To a solution of N-[(benzylaxy)carbonyl]-tert-leucine 3.7 g. 14 mmol) in DMF (80 mL)
were added ammonium chloride (900 mg. 17 mmol), triethylamine (5,9 ml, 42 mmol), HOBI (2.5 g, 18 mmol), and EDC (3.1 g. 18 mmol) at rt
After 17 h, the reaction mixture was quenched by addition of sat. aq. sodium bicarbonate (100 mL) and extracted with ethyl acetate (100 ml. x 3). The combined organic layers were washed with water (100 mL x 3), brine (50 mL), dried over sodium sulfate, filtered and concentrated in vacuo.
Residunya dimurnikan dengan kromatografi kolom pada silika gel yang dielusi dengan heksana/etil asetat (2/1-1/1) hingga menghasilkan 3,0 g (82%)
L-Tert-Leucinamide
To a solution of benzyl ((1S)-1-(aminocarbonyl)-2,2-dimethylpropyl carbamate (3.7 g. 14 mmol) in THF (40mL) was added 10% Pd/C (710 mg). The flask was evacuated and flushed with H₂ gas and this process was repeated three times. The flask was filled with H₂ gas (4 atm) and stirred for 3 h at rt. Then the reaction mixture was filtered through a pad of Celite and concentrated in vacuo to give the title compound as white solid (crude; 1.8 g).