Potassium Carbonate → methyl (R)-2-((S)-2-(5-(4'-(2-((S)-1-((R)-2-methoxycarbonylamino-3-methylbutanoyl)pyrrolidin-2-yl)-1H-benzo[d]imidazol-6-yl)biphenyl-4-yl)-1H-imidazol-2-yl)pyrrolidin-1-yl)-2-oxo-1-phenylethylcarbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-benzyl 2-(5-(4′-(2-((S)-1-((R)-2-(methoxycarbonylamino)-3-methylbutanoyl)pyrrolidin-2-yl)-1H-benzo[d]imidazol-6-yl)biphenyl-4-yl)-1H-imidazol-2-yl)pyrrolidine-1-carboxylate (0.28 g, 0.37 mmol), potassium carbonate (105 mg, 0.75 mmol) and water (1 drop) in ethanol (5 mL) was added 10% palladium on carbon (200 mg). The reaction flask was flushed with argon for 2 minutes. Hydrogen gas was bubbled through the reaction mixture for 10 minutes. The reaction was stirred under hydrogen gas for 18 hours, and then flushed with argon. The mixture was diluted with methanol and filtered through Celite. The filtrate was concentrated and used without purification in the next step. This residue was dissolved in a 5:1 mixture of dichloromethane:dimethylformamide (4.3 mL) and cooled to 0° C. To the solution were sequentially added (R)-2-(methoxycarbonylamino)-2-phenylacetic acid (98 mg, 0.47 mmol) and COMU (202 mg, 0.47 mmol). After one hour, the reaction was diluted with acetonitrile (2 mL) and methanol (2 mL). To this solution was added ten drops of 5M aqueous NaOH solution and stirring was continued for 30 minutes. The reaction was diluted with ethyl acetate and the organic layer was washed with water and brine. The combined aqueous washings were extracted three times with ethyl acetate, and the combined organic layers were dried (MgSO4) and concentrated. The crude material was purified by preparative reverse phase HPLC (Gemini, 15 to 50% ACN/H2O+0.1% HCO2H), followed by flash column chromatography to yield methyl (R)-2-((S)-2-(5-(4′-(2-((S)-1-((R)-2-methoxycarbonylamino-3-methylbutanoyl)pyrrolidin-2-yl)-1H-benzo[d]imidazol-6-yl)biphenyl-4-yl)-1H-imidazol-2-yl)pyrrolidin-1-yl)-2-oxo-1-phenylethylcarbamate (165 mg, 55%). LCMS-ESI+: calculated for C47H50N8O6: 822.95; observed [M+1]+: 823.87.

Provenance & Evidence