Hydrochloric Acid → Benzyl {2-[methoxy(methyl)amino]-1,1-dimethyl-2-oxoethyl}carbamate

Participants

Reaction Conditions

Reaction Steps

N-Methylmorpholine (682 mg, 741 μL, 6.74 mmol) and isobutylchloroformate (460 mg, 441 μL, 3.37 mmol) were added successively to a stirred solution of N-carbobenzyloxy-2-methylalanine (0.64 g, 2.69 mmol) in dry CH2Cl2 at 0° C. under N2. The resulting cloudy mixture was stirred at 0° C. for 90 min. N,O-Dimethylhydroxylamine hydrochloride (316 mg, 3.24 mmol) was added portionwise and the mixture was warmed to room temperature and stirred for 3 h. The mixture was poured into 1N HCl (30 mL) and extracted with CH2Cl2 (3×40 mL). The combined extracts were washed with 1N HCl (30 mL), dried (Na2SO4) and concentrated in vacuo to give the crude product. This was purified by flash chromatography (Si, 40×160 mm, 0-80% EtOAc in hexanes gradient) to afford benzyl {2-[methoxy(methyl)amino]-1,1-dimethyl-2-oxoethyl}carbamate. Rf=0.47 (50% EtOAc in hexanes). LCMS calc.=303.1; found=303.2 (M±Na)+. 1H NMR (500 MHz, CDCl3) δ 7.37-7.29 (m, 5H), 5.82 (s, 1H), 5.09 (s, 2H), 3.60 (s, 3H), 3.18 (s, 3H), 1.60 (s, 6H).

Provenance & Evidence