Hydrochloric Acid → (S)-Benzyl 2-((tert-butoxycarbonyl)amino)-5-hydroxypentanoate

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Reaction Steps

To a solution of 7.0 g Boc-Glu-OBn in 100 ml THF were added dropwise under Argon at −10° C. 2.9 ml N-ethylmorpholine and 3.0 ml isobutyl chloroformate. The reaction mixture was stirred for 10 minutes before 2.4 g sodium borohydride were added. Methanol (400 ml) was added slowly over a period of 70 minutes at this temperature. It was stirred for additional 30 minutes at RT before being neutralized with 1 N HCl. The mixture was concentrated, dissolved in ethyl acetate and washed with 1 N HCl and brine. The crude product obtained after evaporation of the solvent was purified by flash chromatography on silica using an ethyl acetate/heptane gradient. Yield: 5.3 g.

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