Dimethylformamide → N-[2-(t-butoxycarbonylamino)-2-methyl-1-oxopropyl]-L-tyrosine ethyl ester

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Reaction Steps

To a stirred solution of L-tyrosine ethyl ester (2.10 g, 10.0 mmol) and N-t-butoxy-carbonyl-α-methylalanine (2.03 g, 10.0 mmol) in dimethylformamide (40 mL) is added 1,3-dicyclohexylcarbodiimide (2.26 g, 11.0 mmol) and 1-hydroxybenzotriazole (1.48 g, 11.0 mmol). The mixture is stirred overnight and then water (50 mL) is added. The aqueous phase is extracted with ethyl acetate (3×75 mL). The combined organic phases are washed with a saturated solution of sodium bicarbonate (25 mL), brine, dried over magnesium sulfate and the solvent is removed to give a light yellow oil. The oil is purified by flash chromatography (SiO2 :hexane/ethyl acetate) to afford N-[2-(t-butoxy-carbonylamino)-2-methyl-1-oxopropyl]-L-tyrosine ethyl ester as a white solid.

Provenance & Evidence