Example 139 Synthesis of N-methoxy-N-methylchloroacetamide: N,O-dimethylhydroxylamine hydrochloride (200 g, 2.05 mol) was dissolved in tert-butyl methyl ether (2 L), and the solution was slowly added to an aqueous solution of potassium carbonate (624 g, 4.1 mol) (2 L) that was pre-cooled to 0 °C. The reaction mixture was further cooled to -5 °C, followed by the slow dropwise addition of chloroacetyl chloride, controlling the reaction temperature to not exceed 5 °C. After the dropwise addition, the reaction mixture was gradually warmed up to room temperature with continuous vigorous stirring for 3.5 hours. After completion of the reaction, the organic and aqueous phases were separated and the aqueous phase was extracted with tert-butyl methyl ether (3 x 1 L). All organic phases were combined, washed with saturated aqueous sodium chloride solution (2 x 1 L), dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was dried under vacuum to give a white solid product (257 g, 92% yield). The product was characterized by the following data: melting point 39-40.5 °C; 1H NMR (CDCl3, 300 MHz) δ 4.24 (s, 2H), 3.74 (s, 3H), 3.22 (s, 3H); mass spectra (CI) m/z 138 (MH+); elemental analysis (C4H8ClNO2) calculated values: C, 34.92; H, 5.86; N, 10.18; measured values. 10.18; measured values: C, 35.06; H, 5.88; N, 10.23.
