H-Glu(OMe)-OtBu

540-88-5

3077-51-8

79640-72-5

GENERAL METHOD: Under vigorous stirring conditions, 82 mL of tert-butyl acetate was slowly added to 2.45 mL of 58% HClO4 solution containing 12.2 mmol of methyl ester 6 or 7 hydrochloride. The reaction mixture was stirred continuously at room temperature for 72 hours. Upon completion of the reaction, the mixture was slowly poured into a mixture of 270 mL of 10% Na2CO3 solution with 40 mL of Et2O that had been pre-cooled to 5°C. After separation of the organic phase, the aqueous phase was extracted with Et2O (2 x 70 mL) to recover the reaction product. All organic phases were combined and washed sequentially with 10% Na2CO3 solution (2 × 100 mL), dried over anhydrous Na2SO4 and subsequently concentrated under reduced pressure. The crude product was purified by fast column chromatography with the eluent CH2Cl2-MeOH (98:2, v/v).