Water → tert-Butyl {(1S,2R)-1-benzyl-2-hydroxy-3-[(5-methyl-1H-imidazol-2-yl)amino]-3-oxopropyl}carbamate

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Reaction Steps

To a 5.00 ml solution of benzyl 2-amino-4-methyl-1H-imidazole-1-carboxylate obtained in Reference Example 32 601 mg (2.60 mmol), (2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-4-phenylbutanoic acid 590 mg (2.00 mmol) and HOBt.H2O 321 mg (2.10 mmol) in DMF was added WSC.HCl 422 mg (2.20 mmol) and the mixture was stirred at room temperature for 5 hours. After distillating DMF off, the mixture was extracted by adding ethyl acetate and 5% aqueous sodium carbonate solution. The organic layer was washed with an aqueous saturated sodium chloride solution and dried on sodium sulfate. Filtration and concentration gave a residue and the resulting residue was redissolved in methanol 30 mL. To this solution were added ammonium formate 2.52 g (40.00 mmol), 10% Pd/C (containing 50% water) and the mixture was heated under reflux for 2 hours. The mixture was filtered to remove 10% Pd/C and concentrated. The concentrated residue was suspended in ethyl acetate and washed with 5% sodium carbonate and an aqueous saturated sodium chloride solution. The organic layer was dried on sodium sulfate. After filtration and concentration of the mixture, the mixture was purified by a column chromatography on silica gel (eluted with a mixed solvent of chloroform and methanol) to give 558 mg (1.49 mmol) of the title compound (yield: 75%).

Provenance & Evidence