Phosphoric Acid → [(Tert-butoxy)carbonylamino]-3,4-dihydroxy-N-(phenylmethoxy)butanamide

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Reaction Conditions

Reaction Steps

To solution of tetrahydrofuran (THF, 6 L) and phosphoric acid buffer (0.025 M, KH2PO4/Na2HPO4; ratio 1/1, 2 L) containing ethyl 3-[(tert-butoxy)carbonylamino]-2-hydroxy-3-[N-(phenylmethoxy) carbamoyl]propanoate (compound prepared from diethyl tartrate according to the procedures described in Org. Synth., Coll. Vol. 1998, 220, J. Org. Chem. 1983, 3556 and U.S. Pat. No. 4,794,108) (120 g, 31.38 mmol), sodium borohydride (59.35 g, 156.9 mmol) was added portion wise at 0° C. over 1 h. The resulting mixture was stirred at 0° C. for an additional 1 h and at room temperature for 2 h. The micxture was cooled at 0° C. before addition of 1M aqueous solution containing H3PO4 until the pH reach 8. NaCl (100 g) was added to the mixture and the organic layer was separated. Extraction with ethyl acetate (3×1.5 L) was performed and the combined organic phases were washed with brine (1 L), dried over MgSO4 and evaporated under vacuo. The residue as purified by column chromatography using hexane/acetone as eluent to get 50 g of white solid.

Provenance & Evidence