To 2-aminomethyl-pyrrolidine-1-carboxylic acid tert-butyl ester (1.00 g, 4.97 mmol) and 4-bromo-benzoic acid (996 mg, 4.97 mmol) in DMF (25 mL) was added N-methylmorpholine (655 μl, 5.96 mmol) and HATU (1.89 g, 4.97 mmol). After stirring for 3 hours the reaction was concentrated then diluted with EtOAc and washed with 1N HCl, saturated NaHCO3, and brine. The organic phase was then dried over Na2SO4 and concentrated. The crude material was purified by silica gel chromatography (20-50% EtOAc-hexanes gradient) to afford 2-[(4-bromo-benzoylamino)-methyl]-pyrrolidine-1-carboxylic acid tert-butyl ester (1.91 g, 4.97 mmol, quantitative yield). LCMS-ESI+: calc'd for C17H24BrN2O3: 383.1 (M+H+). Found: 383.6 (M+H+). (1-{2-[(4-Bromo-benzoylamino)-methyl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester: To 2-[(4-bromo-benzoylamino)-methyl]pyrrolidine-1-carboxylic acid tert-butyl ester (1.00 g, 2.61 mmol) in dioxanes (15 mL) was added 4N HCl in dioxanes (5 mL, 20 mmol). The solution was stirred overnight then concentrated to afford the HCl salt of the crude amine. To the amine in DMF (13 mL) was added N-methylmorpholine (574 μl, 5.22 mmol), 2-methoxycarbonylamino-3-methyl-butyric acid (457 mg, 2.61) and HATU (992 mg, 2.61 mmol). After stirring for 2 hours the reaction was concentrated then diluted with EtOAc and washed with 1N HCl, saturated NaHCO3, and brine. The crude product was purified by silica gel chromatography (100% EtOAc) to afford (1-{2-[(4-bromo-benzoylamino)-methyl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (950 mg, 2.18 mmol, 84% yield). LCMS-ESI+: calc'd for C19H27BrN3O4: 440.1 (M+H+). Found: 440.2 (M+H+). [1-(2-{[(4′-{2-[1-(2-methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-biphenyl-4-carbonyl)-amimo]-methyl}-pyrrolidine-1-carbonyl)-2-methyl-propyl]-carbamic acid methyl ester: A solution of (1-{2-[(4-bromo-benzoylamino)-methyl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (104 mg, 0.24 mmol), [2-methyl-1-(2-{5-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-1H-imidazol-2-yl}-pyrrolidine-1-carbonyl)-propyl]-carbamic acid methyl ester (117 mg, 0.24 mmol) and aq K3PO4 (480 μl of a 2M solution, 0.96 mmol) in DME (3 mL) was degassed with N2 gas for 20 minutes. To the degassed solution was added Pd(PPh3)4 (13.9 mg, 0.012 mmol) then the reaction was heated to 80° C. overnight. After cooling to room temperature, the reaction was concentrated and purified by reverse phase preparative HPLC (15-60% MeCN—H2O; 0.1% formic acid modifier) to afford [1-(2-[(4′-{2-[1-(2-methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl]-biphenyl-4-carbonyl)-amino]-methyl}-pyrrolidine-1-carbonyl)-2-methyl-propyl]-carbamic acid methyl ester (26 mg, 0.036 mmol, 15% yield). 1H-NMR: 400 MHz, (DMSO-d6) δ: 11.8 (s, 1H), 8.61 (m, 1H), 7.94-7.73 (m, 9H), 7.34 (d, 1H), 7.29 (d, 1H), 5.08 (m, 1H), 4.23 (t, 1H), 4.30 (m, 1H), 4.07 (t, 1H), 4.01 (t, 1H), 4.07-4.01 (m, 1H), 3.18 (m, 2H), 3.73-3.70 (m, 1H), 3.61 (m, 1H), 3.63 (s, 3H), 3.61 (s, 3H), 2.16-1.81 (m, 10H), 0.90-0.84 (m, 12H). LCMS-ESI+: calc'd for C39H52N7O7: 730.4 (M+H+). Found: 730.1 (M+H+).
