Synthesis
                    3,4-dimethoxybenzaldehyde (50 g, 0.33 mol) and ammonium acetate (50 g) were mixed in 95% ethanol (50 ml). The mixture was heated to 50 °C, followed by slow addition of malonic acid (63 g, 0.6 mol) and supplemented with 95% ethanol (25 ml). The reaction mixture was refluxed for 3 hours and then the reaction was continued at 80°C for 24 hours. Upon completion of the reaction, the precipitate was collected by filtration, washed with ethanol and recrystallized in 50% ethanol to afford 47.8 g of the target product 3-amino-3-(3,4-dimethoxyphenyl)propionic acid as a white solid (yield: 65%). The product was characterized by 1H NMR (300 MHz, D2O): δ 6.90-6.87 (m, 3H), 4.44-4.39 (t, 1H), 3.69 (s, 3H), 3.67 (s, 3H), 2.76-2.57 (m, 2H). Mass spectrum (EI) m/z: 226 (M++H).
  
                 
                
                    References
                    [1] Chemical Communications,  2011,  vol. 47,  # 20,  p. 5894 - 5896
[2] Patent: WO2010/16939,  2010,  A1. Location in patent: Page/Page column 57
[3] Synlett,  2013,  vol. 24,  # 6,  p. 733 - 736
[4] ACS Medicinal Chemistry Letters,  2014,  vol. 5,  # 11,  p. 1207 - 1212
[5] Tetrahedron Asymmetry,  2008,  vol. 19,  # 17,  p. 2072 - 2077