Synthesis
Take L-threonine methyl ester into the round bottom flask, add anhydrous ethanol and rotor in the round bottom flask, put the round bottom flask into the silicone oil heating furnace heating to 80 , when the liquid becomes uniform, add potassium hydroxide to the round bottom flask, the reaction for 1 hour the liquid from turbid to transparent, add tert-butyllithium, the liquid becomes transparent light yellow. Continue the reaction for 2 hours, the color of the liquid remained unchanged, thin-layer chromatography to detect the progress of the reaction, to be L-Threonine methyl ester reaction is complete to stop the reaction. After cooling to room temperature and filtering, a light yellow powder was obtained. In a round-bottomed flask, add anhydrous dioxane and rotor in a round-bottomed flask, L-threonine methyl ester suspended in dioxane solution, and acylation reaction with fluorenylmethoxycarbonyl azide, thin-layer chromatography to detect the progress of the reaction, to wait for the reaction of O-tert-butyl-L-threonine is complete after the reaction was stopped to obtain the crude O-tert-butyl-L-threonine methyl ester hydrochloride, extracted with ethyl acetate under the condition of pH 9-10 The crude O-tert-butyl-L-threonine methyl ester hydrochloride was extracted with ethyl acetate at pH 9-10 and refined by recrystallization.
