34993-02-7

637-59-2

1068-90-2

34993-02-7

Example 5 (±)-Synthesis of 2-amino-5-phenylpentanoic acid: under nitrogen protection, diethyl acetamidomalonate (220 g) was dissolved in 1 L of anhydrous ethanol, and added to a sodium ethanolate solution pre-prepared from sodium (24 g) dissolved in 500 mL of anhydrous ethanol. The reaction mixture was refluxed under nitrogen for 30 min before 1-bromo-3-phenylpropane (200 g) was added. The reaction was continued at reflux overnight, cooled to room temperature, filtered to remove the precipitate and the solvent was removed by distillation under reduced pressure. Concentrated hydrochloric acid (800 mL) was added to the residue and the reaction was refluxed for 14 hours. After cooling, the aqueous phase was washed with water (2 x 200 mL) and residual ether in the aqueous phase was removed by nitrogen bubbling. The pH of the aqueous phase was adjusted to 7-8 with ammonium hydroxide, the target product was collected by filtration, dried over air and recrystallized from ethanol-water mixed solvent to give 150 g (83% yield) of the title compound. Melting point: 255°-257°C. Mass spectrum (FAB) m/e: 194 (M+H)+.