General procedure for the synthesis of 2-(((benzyloxy)carbonyl)(methyl)amino)acetic acid from sarcosine and benzyl chloroformate: sarcosine (3.00 g, 33.67 mmol) was added to an aqueous solution (100 mL) containing NaOH (3.24 g, 80.90 mmol) and stirred homogeneously under ice-water bath conditions. Subsequently, benzyl chloroformate (CbzCl, 6.89 g, 40.39 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 16 h, during which the reaction progress was monitored by TLC. Upon completion of the reaction, the reaction mixture was washed with ethyl acetate (2 × 100 mL) and the aqueous layer was adjusted to pH 2 with 1 M hydrochloric acid before extraction with ethyl acetate (2 × 150 mL). All ethyl acetate extracts were combined, washed with saturated NaCl solution and subsequently dried with anhydrous Na2SO4 (100 mL). The dried solution was filtered and concentrated under reduced pressure to afford the colorless oily product 2-(((benzyloxy)carbonyl)(methyl)amino)acetic acid (Compound 4, 7.11 g, 94% yield).
