1,4-Dibromobenzene → (1-{2-[5-(4-bromo-phenylethynyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

{1-[2-(5-Ethynyl-1H-imidazol-2-yl)-pyrrolidine-1-carbonyl]-2-methyl-propyl}-carbamic acid methyl ester (57 mg, 0.179 mmol), 1,4-dibromobenzene (211 mg, 0.895 mmol), Pd(PPh3)4 (10 mg, 0.00895 mmol), CuI (3 mg, 0.0179 mmol) and triethylamine (0.249 mL, 1.79 mmol) were suspended in DMF (2 mL) and the mixture was degassed for 10 min with nitrogen. The reaction mixture was stirred at 80° C. for 70 min then diluted with 20 mL ethyl acetate and washed with saturated aqueous sodium bicarbonate and brine. The organic phase was dried with magnesium sulfate and concentrated. The crude residue was purified by silica column chromatography (0% to 5% MeOH/DCM) to afford (1-{2-[5-(4-Bromo-phenylethynyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (43 mg, 51%). (1-{2-[5-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-ylethynyl}-phenylethynyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester: {1-[2-(5-Ethynyl-1H-imidazol-2-yl)-pyrrolidine-1-carbonyl]-2-methyl-propyl}-carbamic acid methyl ester (49 mg, 0.154 mmol), (1-{2-[5-(4-bromo-phenylethynyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (43 mg, 0.0908 mmol), Pd(PPh3)4 (10 mg, 0.00908 mmol), CuI (2 mg, 0.00908 mmol) and triethylamine (0.127 mL, 0.908 mmol) were suspended in DMF (2 mL) and the mixture was degassed for 10 min with nitrogen. The reaction mixture was stirred at 80° C. for 4 hours then cooled to RT. Formic acid (0.1 mL) and water (1 mL) were added and the mixture was purified by reverse phase preparative HPLC, giving (1-{2-[5-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-ylethynyl}-phenylethynyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (11 mg, 17%). 1H NMR (MeOH-d4, 400 MHz) 7.46 (d, J=3.9 Hz, 4H), 7.25 (s, 2H), 6.96 (d, J=8.4 Hz, 2H), 5.10 (m, 2H), 4.20 (m, 2H), 3.97 (m, 2H), 3.83 (m, 2H), 3.64 (s, 6H), 2.32-2.00 (m, 10H), 0.98-0.88 (m, 12H); MS (ESI) m/z 711 [M+H]+.

Provenance & Evidence