Diethyl 2-aminomalonate hydrochloride (1.69 g, 8.0 mmol) and triethylamine (3.4 mL, 24 mmol, 3.0 eq.) were dissolved in dichloromethane (120 mL) at 0 °C. Acetyl chloride (0.57 mL, 8.0 mmol, 1.0 eq.) was added slowly and dropwise with stirring and the reaction mixture was gradually warmed to room temperature and stirred overnight. After completion of the reaction, the mixture was diluted with dichloromethane (100 mL) and washed sequentially with 1 M hydrochloric acid (3 x 60 mL). The aqueous phase was then back-extracted with dichloromethane (2 x 60 mL), the organic layers were combined and dried over anhydrous magnesium sulfate. The solvent was removed by concentration under reduced pressure to give a pure white solid product. Yield: 1.68 g (96% yield). The product was characterized as follows: melting point 96 °C (literature value 97 °C); 1H NMR (300 MHz, CDCl3) δ [ppm]: 1.30 (t, J=7.1Hz, 6H, 7-CH3,9-CH3), 2.08 (s, 3H, 5-CH3), 4.27 (m, 4H, 6-CH2,8-CH2), 5.18 (d, J=7.1Hz, 1H), 5.18 (d, J=7.1Hz, 1H). 7.1 Hz, 1H, 2-CH), 6.67 (d, J=5.7 Hz, 1H, 2-NH); 13C NMR (75 MHz, CDCl3) δ [ppm]: 14.0 (q, C-7, C-9), 22.8 (q, C-5), 56.5 (d, C-2), 62.6 (t, C-6, C-8), 166.5 (s, C -1, C-3), 169.9 (s, C-4); high-resolution mass spectrometry (ESI+): 240.0842 calculated value for C9H15N5O+Na+, 240.0824 measured value.
