Acetic Anhydride → 5-[2-(S)-Acetylamino-1-(S)-hydroxy-3-(3-hydroxyphenyl)-propyl]-2-(R)-(2,2-dimethylpropoxy)-3-(S)-methylmorpholine-4-carboxylic acid tert-butyl ester

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Reaction Steps

Add acetic anhydride (320 μL, 3.4 mmol) and N,N-diisopropylethylamine (590 μL, 3.4 mmol) to a solution of 5-(R)-[2-(S)-amino-1-(S)-hydroxy-3-(3-hydroxyphenyl)-propyl]-2-(R)-(2,2-dimethylpropoxy)-3-(S)-methylmorpholine-4-carboxylic acid tert-butyl ester (770 mg, 1.70 mmol). Stir for 2.5 hours. Dilute with ethyl acetate, wash with 1 N hydrochloric acid (twice), saturated aqueous sodium bicarbonate, saturated aqueous sodium chloride, dry (magnesium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 20:80 to 25:75 ethyl acetate:hexanes) to give the desired compound (292 mg).

Provenance & Evidence