Cl.[CH3:2][O:3][C:4](=[O:9])[C:5]([NH2:8])([CH3:7])[CH3:6].C(=O)([O-])[O-].[K+].[K+].[Cl:16][CH2:17][C:18](Cl)=[O:19]>C(OCC)(=O)C.O>[Cl:16][CH2:17][C:18]([NH:8][C:5]([CH3:7])([CH3:6])[C:4]([O:3][CH3:2])=[O:9])=[O:19]To a rapidly stirring biphasic solution of aminoisobutyric acid methyl ester hydrochloride (5.1 g, 33 mmol) in ethyl acetate (40 mL) and water (27 mL) was added potassium carbonate (13.7 g, 99.6 mmol) followed by chloroacetyl chloride (3.4 mL, 43 mmol). The reaction was cooled with an ice bath to prevent warming above ambient temperature, and stirred at room temperature for four hours. The mixture was diluted with ethyl acetate and the organic layer was successively washed with 10% citric acid and sat. NaCl, dried over sodium sulfate and concentrated in vacuo to give the desired product as a white solid (5.78 g, 29.9 mmol, 91%). 1H NMR (CDCl3, 400 MHz) δ 1.61 (s, 6H), 3.78 (s, 3H), 4.01 (s, 2H); LRMS (ESI/APCI) m/z 194 [M+H]+.
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