反应详情

温度

0 °C

To a stirred solution of 3-{[(benzyloxy)carbonyl]amino}-butanoic acid (Step A; 9.0 g; 38 mmol) in CH2Cl2 (90 mL) at 0° C. under N2 were added N-methylmorpholine (10.4 mL; 95 mmol) and isobutyl chloroformate (6.2 ml; 47.5 mmol). The resultant yellow solution was stirred at 0° C. for 5 min prior to portionwise addition of N,O-dimethylhydroxylamine hydrochloride (4.45 g; 45.6 mmol) over 5 min. The reaction was allowed to warm to room temperature and stirred for 14 h, then poured into 1 N HCl (200 mL) and extracted with CH2Cl2 (3×100 mL). The combined extracts were washed with 1 N HCl (100 mL), dried (MgSO4), filtered and concentrated in vacuo. The residue was purified by flash silica gel chromatography (0-50% EtOAc/hexanes gradient) to afford benzyl-{3-[methoxy(methyl)amino]-1-methyl-3-oxopropyl}carbamate as a clear oil. LCMS=281.3 (M+1)+. 1H NMR (CDCl3, 500 MHz): δ 7.35-7.29 (m, 5H), 5.61 (br s, 1H), 5.09 (s, 2H), 4.16-4.10 (m, 1H), 3.66 (s, 3H), 3.16 (s, 3H), 2.77-2.72 (m, 1H), 2.59-2.54 (m, 1H), 1.27 (d, J=6.6 Hz, 3H).

1. temperatureto warm to room temperature
2. stirringstirred for 14 h
3. extractionextracted with CH2Cl2 (3×100 mL)
4. washThe combined extracts were washed with 1 N HCl (100 mL)
5. dry with materialdried (MgSO4)
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe residue was purified by flash silica gel chromatography (0-50% EtOAc/hexanes gradient)