(1R,3S,4S)-tert-butyl 3-(5-(4-(2-((S)-1-((S)-2-(methoxycarbonylamino)-3-methylbutanoyl)pyrrolidin-2-yl)-1H-naphtho[1,2-d]imidazol-7-yl)phenyl)-1H-imidazol-2-yl)-2-azabicyclo[2.2.1]heptane-2-carboxylate (73 mg, 0.0997 mmol) was dissolved in DCM (5 mL) and treated with HCl (4M in dioxane, 1 mL). After 3 h, the reaction mixture was concentrated. The residue was treated with (2S,3R)-3-methoxy-2-(methoxycarbonylamino)butanoic acid (23 mg, 0.120 mmol), COMU (51 mg, 0.120 mmol) and DMF (2 mL). DIPEA (0.090 mL, 0.499 mmol) was added and the reaction mixture was stirred for 25 min before being quenched with H2O and purified by HPLC to afford the title compound (22 mg, 28%). (ESI) m/z 805 [M+H]+.
