反应详情

(2S)-3-Methyl-2-methylamino-butanoic acid (5 g, 38.12 mmol) is added to a stirring solution of sodium hydroxide (76.2 mL of 1 M, 76.24 mmol). After complete dissolution, sodium carbonate (2.1 g, 19.82 mmol) is added followed by methyl chloroformate (3.18 mL, 41.17 mmol) at 0° C. over 40 minutes. The reaction mixture is stirred at rt for 4 hours, and then washed with diethyl ether (2×75 ml). The aqueous layer is cooled to 0° C., acidified to pH 1-2 and extracted with CH2Cl2. The organic phase is dried over MgSO4, filtered and concentrated to dryness to give the title compound (2S)-2-[methoxycarbonyl(methyl)amino]-3-methyl-butanoic acid (5.12 g, 71%) as a clear oil.

1. additionis added
2. washwashed with diethyl ether (2×75 ml)
3. temperatureThe aqueous layer is cooled to 0° C.
4. extractionextracted with CH2Cl2
5. dry with materialThe organic phase is dried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated to dryness