62129-39-9

24424-99-5

24250-84-8

62129-39-9

General procedure for the synthesis of (S)-3-(4-bromophenyl)-2-((tert-butoxycarbonyl)amino)propionic acid from di-tert-butyl dicarbonate and L-4-bromophenylalanine: To a mixed solution of (S)-2-amino-3-(4-bromophenyl)propionic acid (7.3 g, 30.0 mmol) in methanol (50 mL) and water (50 mL) was slowly added di-tert-butyl dicarbonate ( 6.9 g, 31.5 mmol). The reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the solvent was removed by rotary evaporator. The residue was adjusted to pH=5 with dilute hydrochloric acid and then extracted with ethyl acetate (10 mL x 3). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and concentrated to afford (S)-3-(4-bromophenyl)-2-((tert-butoxycarbonyl)amino)propionic acid in white solid form (10.0 g, 96.9% yield), which could be used in the subsequent reaction without further purification.