Methyl iodide → 4-tert-Butyl 1-methyl N-[(benzyloxy)carbonyl]-L-aspartate

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Reaction Steps

To Cbz-Asp(O-tert-Bu)-OH.H2O (5.00 g, 14.6 mmol) and K2CO3 (4.05 g, 2.0 eq) were added DMF (100 mL) and MeI (2.74 mL, 3 eq), which was then stirred for 2-3 h at room temperature. The solvent was distilled under reduced pressure. The residue was extracted with ethyl acetate (100 mL×2), washed with water, aqueous sodium hydrogen carbonate solution and aqueous sodium chloride solution, dried (anhydrous Na2SO4), and concentrated under reduced pressure. The residue was purified by column chromatography (30% ethyl acetate/hexane) to give (S)-2-benzyloxycarbonylamino-succinic acid 4-tert-butyl ester 1-methyl ester in a stoichiometric yield. This compound was dissolved in MeOH (100 mL), c-HCl (1.1 mL, 1.0 eq) was added, and subjected to debenzyloxycarbonylation (Pd/C) for 40 min under hydrogen balloon, whereby giving 3.28 g (96%) of the title compound.

Provenance & Evidence