Methanol → Ethyl N-(methoxycarbonyl)glycinate

Alternatively, glycine ethyl ester hydrochloride (40.1 g, 0.28 mole) suspended in dry tetrahydrofuran (200 ml) and phosgene were bubbled through the reaction mixture for 0.5 hrs, as the reaction mixture was refluxed. At the end of 0.5 hrs., the reaction was cooled to room temperature and toluene was added followed by the distillation of THF. The reaction mixture containing toluene was further refluxed for 1 hr. The unreacted glycine ethyl ester hydrochloride was filtered and the filtrate containing glycine ethyl ester isocyanate (IR 2250 cm-1) was reacted with excess (2-3 mole) anhydrous methanol and, when the isocyanate peak disappeared, the solvent was removed to isolate N-carbomethoxyglycine ethyl ester.