Water → (2R,4S)-5-biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methyl-pentanoic acid benzyl ester

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Reaction Steps

To a solution of (2R,4S)-5-biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methyl-pentanoic acid (prepared using the procedure described in WO 2008083967)(1.0 g, 2.61 mmol) and benzyl bromide (468 mg, 2.74 mmol) in DMF (15 mL) is added potassium carbonate (541 mg, 3.91 mmol) and the mixture is stirred at room temperature for 2 hours. Water is added and the mixture is extracted with ethyl acetate. The combined organic layers are washed with water and dried over magnesium sulfate. The solvent is removed under reduced pressure and the residual oil is purified by column chromatography using heptane/EtOAc (4:1) to furnish (2R,4S)-5-biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methyl-pentanoic acid benzyl ester. Next, to a solution of (2R,4S)-5-biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methyl-pentanoic acid benzyl ester in THF (5 mL) is added 4M HCl in dioxane (3 mL) and the solution is stirred at room temperature for 1 hour. The solvent is removed under reduced pressure to give the title compound. MS 374.4 (M+1).

Provenance & Evidence