Glycine (Gly) (0.5 g, 6.66 mmol) was dissolved in 10% NaCO
3 (14 ml) under stirring in a 50-ml flask. To the resulting solution, which had been put into an ice bath, 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) (1.72 g, 6.66 mmol) in dioxane (12 ml) was gradually added. The reaction mixture was stirred at room temperature for 4 hours. Then added water (150 ml) to the mixture. The aqueous phase layer was separated from the reaction mixture and stripped with ether three times (75 ml×3). The stripped aqueous layer was acidified with 2N HCl aqueous solution to a pH=2, followed by extraction with ethyl acetate three times (75 ml×3). The organic phase layer was recovered and concentrated to obtain crude product of 1.70 g. The crude product was recrystallized in a mixed solvent of ethyl acetate hexane=1:2 (30 ml), and white solid denoted as Fmoc-Gly-OH was obtained after filtration at a reduced pressure.
