Synthesis
Ethyl cyanoacetate (30 mL, 281 mmol) was dissolved with anhydrous ethanol (18.1 mL, 278 mmol) in anhydrous ether (28.1 mL) at 0°C and stirred to form a homogeneous solution. Dry hydrogen chloride gas was passed into the solution until saturation. Subsequently, the reaction mixture was warmed up to 22°C with continuous stirring for 20 hours. Upon completion of the reaction, the solvent was removed by concentration under reduced pressure to afford ethyl 3-ethoxy-3-iminopropionate hydrochloride (54.4 g, 99% yield). The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3): δ 4.73 (q, J = 7.1 Hz, 2H); 4.24 (q, J = 7.2 Hz, 2H); 3.89 (s, 2H); 1.51 (t, J = 7.0 Hz, 3H); 1.30 (t, J = 7.2 Hz, 3H) ppm.
References
[1] Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 23, p. 7207 - 7213
[2] Chemical and Pharmaceutical Bulletin, 1985, vol. 33, # 7, p. 3046 - 3049
[3] Heterocycles, 1996, vol. 43, # 9, p. 1981 - 1989
[4] Tetrahedron, 2009, vol. 65, # 4, p. 757 - 764
[5] Patent: WO2006/7700, 2006, A1. Location in patent: Page/Page column 66-67