To 30 mL of ethanol was added 5.00 g (27.0 mmol) of p-bromobenzaldehyde, 2.80 g (27.0 mmol) of malonic acid, and 3.10 g (40.2 mmol) of ammonium acetate, and the reaction mixture was refluxed and stirred for 10 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 4.8 g of DL-3-amino-3-(4-bromophenyl)propionic acid (racemic mixture) in 72.2% isolated yield based on p-bromobenzaldehyde, and the product was a white powder.The physical properties of DL-3-amino-3-(4-bromophenyl)propionic acid (racemic mixture) 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.
