Hydrochloric Acid → methyl(2S,3R)-1-((S)-2-(5-bromo-1H-imidazol-2-yl)pyrrolidin-1-yl)-3-methoxy-1-oxobutan-2-ylcarbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of (5)-tert-butyl 2-(5-bromo-1H-imidazol-2-yl)pyrrolidine-1-carboxylate (1.00 g, 3.2 mmol) in a mixture of CH2Cl2 (30 mL) and MeOH (5 mL) was added HCl (in dioxane, 4 M, 11.5 mL, 46.0 mmol). The solution was stirred at 40° C. for 1 h, cooled to room temperature, and concentrated to dryness under reduced pressure. To the crude intermediate suspended in CH2Cl2 (30 mL) was added (2S,3R)-3-methoxy-2-(methoxycarbonylamino)butanoic acid (0.67 g, 3.5 mmol), HATU (1.47 g, 3.8 mmol), and DIPEA (1.00 mL, 6.0 mmol). The resulting solution was stirred at room temperature for 24 h. DMF (2 mL) and aqueous LiOH (2.5 M, 1 mL) were added and the reaction was concentrated to dryness under reduced pressure. The crude material was diluted with EtOAc and washed with H2O and brine. The aqueous layers were backextracted with EtOAc. The combined organic layers were dried over Na2SO4 and concentrated under reduced pressure. The crude residue was purified by silica column chromatography (20% to 100% EtOAc (w/5% MeOH)/CH2Cl2) to afford methyl(2S,3R)-1-((S)-2-(5-bromo-1H-imidazol-2-yl)pyrrolidin-1-yl)-3-methoxy-1-oxobutan-2-ylcarbamate (1.2 g, 100%).

Provenance & Evidence