To 25 mL of ethanol were sequentially added 5.00 g (35.6 mmol) of 4-chlorobenzaldehyde, 3.70 g (35.6 mmol) of malonic acid and 4.10 g (53.2 mmol) of ammonium acetate, and the reaction mixture was stirred at reflux for 8 hr at 75 to 80°C. The reaction was carried out by stirring the mixture for 1 hr at room temperature. After completion of the reaction, the mixture was continued to be stirred at room temperature for 1 h. Subsequent filtration afforded 5.9 g of 3-amino-3-(4-chlorophenyl)propionic acid (racemic mixture) as a white powder (82.3% isolated yield based on 4-chlorobenzaldehyde). The physical properties of the compound were as follows: 1H-NMR (δ, ppm, D2O): 2.93 (dd, 1H, J = 17.1, 6.8 Hz), 3.04 (dd, 1H, J = 17.1, 7.8 Hz), 4.63 (dd, 1H, J = 7.8, 6.8 Hz), 7.22 (s, 1H), 7.24 (s, 1H), 7.47 (s, 1H), 7.49 (s, 1H); 13C-NMR (δ, ppm, D2O): 40.4, 53.9, 126.0, 131.9, 135.3, 137.1, 175.9; MS (EI) m/z: 199 (M+); MS (CI, i-C4H10) m/z: 200 (MH+).
