Hydrochloric Acid → methyl {(2S)-1-[(2R)-2-(5-{2-[(2S)-1-{(2R)-2-[(methoxycarbonyl)amino]-2-phenylacetyl}pyrrolidin-2-yl]-3,7-dihydroisochromeno[3',4':5,6]naphtho[1,2-d]imidazol-9-yl}-1H-imidazol-2-yl)pyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl}carbamate

Participants

Reaction Conditions

Reaction Steps

A mixture of tert-butyl (2S)-2-[9-(2-{(2R)-1-[N-(methoxycarbonyl)-L-valyl]pyrrolidin-2-yl}-1H-imidazol-5-yl)-3,7-dihydroisochromeno[3′,4′:5,6]naphtho[1,2-d]imidazol-2-yl]pyrrolidine-1-carboxylate (270 mg, 0.37 mmol), concentrated HCl (1.5 mL) and ethanol (8 mL) was heated to 60° C. for 1 hour. The reaction was concentrated and redissolved in a minimal amount of methanol. An equal volume of dichloromethane was added and the solution was again concentrated. Dichloromethane was added to the resulting residue and concentrated off two more times. The crude material was dissolved in 5:1 dichloromethane/dimethylformamide (3.8 mL). To this solution was added (R)-2-(methoxycarbonylamino)-2-phenylacetic acid (96 mg, 0.46 mmol), COMU (190 mg, 0.44 mmol) and diisopropylethylamine (0.20 mL, 1.1 mmol). The reaction was stirred at 0° C. for 30 minutes then warmed to room temperature. Upon completion, 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 reverse phase HPLC (Gemini, 15 to 45% ACN/H2O+0.1% TFA) to yield methyl {(2S)-1-[(2R)-2-(5-{2-[(2S)-1-{(2R)-2-[(methoxycarbonyl)amino]-2-phenylacetyl}pyrrolidin-2-yl]-3,7-dihydroisochromeno[3′,4′:5,6]naphtho[1,2-d]imidazol-9-yl}-1H-imidazol-2-yl)pyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl}carbamate (155 mg, 51% yield over 2 steps). LCMS-ESI+: calculated for C46H48N807: 824.92; observed [M+1]+: 825.67.

Provenance & Evidence