General procedure for the synthesis of methyl (S)-3-amino-2-(((benzyloxy)carbonyl)amino)propanoate hydrochloride from compound (CAS: 75760-11-1): 3-amino-N-[(benzyloxy)carbonyl]-L-alanine methyl ester (5.0 g, 21.0 mmol) and anhydrous methanol (100 mL) were added to a flask fitted with a magnetic stir bar. HCl gas was passed into the solution/slurry for about 10 minutes under stirring conditions. After about 2 minutes, an exothermic reaction was observed and the solution changed from turbid white to clear/colorless. After stirring the reaction solution overnight, it was concentrated and dried by vacuum to afford methyl (S)-3-amino-2-(((benzyloxy)carbonyl)amino)propionate hydrochloride (6.0 g, 98% yield) as white crystals.1H NMR (δ): 3.05 (t, 1H), 3.19 (t, 1H), 3.70 (s, 3H), 4.45 (m, 1H), 5.10 ( s, 2H), 7.38 (m, 5H), 7.95 (d, 1H), 8.35 (br s, 3H).LCMS (ES, M + H = 253).