Reaction Steps
Bromine (6.13 mL, 119.3 mmol) was added slowly to a solution of 9,10-dihydro-phenanthrene (10 g, 55.5 mmol) in trimethylphosphate (100 mL). The mixture was stirred at room temperature for 18 hours and concentrated in vacuo. The residue was recrystallized from chloroform to give product 2,7-Dibromo-9,10-dihydro-phenanthrene as a white crystal (9.45 g, 51%). Pyrrolidine-1,2-dicarboxylic acid 2-[2-(7-bromo-9,10-dihydro-phenanthren-2-yl)-2-oxo-ethyl]ester 1-tert-butyl ester. Pd(Ph3)4 (347 mg, 0.3 mmol) and PdCl2(Ph3)2 (210 mg, 0.3 mmol) were added to a mixture 2,7-dibromo-9,10-dihydro-phenanthrene (2.5 g, 7.4 mmol) and tributyl(1-ethoxyvinyl)tin (2.5 mL, 7.4 mL) in 70 mL dioxane. The reaction mixture was flushed with nitrogen, heated at 80° C. for 16 hours, then cooled to ambient temperature. Water (20 mL) and NBS (1.39 g, 7.8 mmol) were added and the mixture was stirred at room temperature for 40 minutes, then diluted with ethyl acetate (300 mL). Washed with water and brine, dried over Na2SO4, filtered and concentrated in vacuo. The obtained residue was suspended in acetonitrile (70 mL). To it was added a solution of pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester (3.2 g, 14.9 mmol) and DIPEA (2.4 mL, 14.1 mmol) in 20 mL acetonitrile. The mixture was stirred at room temperature for 16 hours, then diluted with ethyl acetate (300 mL). The organic layer was washed with NaHCO3 solution and water, dried over Na2SO4, filtered and concentrated in vacuo. The obtained residue was purified by flash chromatography to provide the desired product pyrrolidine-1,2-dicarboxylic acid 2-[2-(7-bromo-9,10-dihydro-phenanthren-2-yl)-2-oxo-ethyl]ester 1-tert-butyl ester as a white solid (1.76 g, 46% over two steps). m/z 514.2, 516.2 (M+H)+. 2-Aza-bicyclo[2.2.1]heptane-2,3-dicarboxylic acid 3-(2-{7-[2-(1-tert-butoxycarbonyl-pyrrolidine-2-carbonyloxy)-acetyl]-9,10-dihydro-phenanthren-2-yl}-2-oxo-ethyl)ester 2-tert-butyl ester. Pd(Ph3)4 (37 mg, 0.03 mmol) and PdCl2(Ph3)2 (22 mg, 0.03 mmol) were added to a mixture of pyrrolidine-1,2-dicarboxylic acid 2-[2-(7-bromo-9,10-dihydro-phenanthren-2-yl)-2-oxo-ethyl]ester 1-tert-butyl ester (410 mg, 0.8 mmol) and tributyl(1-ethoxyvinyl)tin (0.32 mL, 0.96 mmol) in 8 mL dioxane. The reaction mixture was flushed with nitrogen, heated at 80° C. for 16 hours, then cooled to ambient temperature. Water (2 mL) and NBS (171 mg, 0.96 mmol) were added and the mixture was stirred at room temperature for 40 minutes, then diluted with ethyl acetate (100 mL). Washed with water and brine, dried over Na2SO4, filtered and concentrated in vacuo. Half of the obtained residue was suspended in acetonitrile (5 mL) To it was added a solution of 2-aza-bicyclo[2.2.1]heptane-2,3-dicarboxylic acid 2-tert-butyl ester (100 mg, 0.41 mmol) and DIPEA (0.068 mL, 0.39 mmol) in 2 mL acetonitrile. The mixture was stirred at room temperature for 16 hours, then diluted with ethyl acetate (100 mL). The organic layer was washed with NaHCO3 solution and water, dried over Na2SO4, filtered and concentrated in vacuo. The obtained residue was purified by flash chromatography to provide the desired product 2-aza-bicyclo[2.2.1]heptane-2,3-dicarboxylic acid 3-(2-{7-[2-(1-tert-butoxycarbonyl-pyrrolidine-2-carbonyloxy)-acetyl]-9,10-dihydro-phenanthren-2-yl}-2-oxo-ethyl)ester 2-tert-butyl ester as a white solid (171 mg, 60% over two steps). m/z 717.2 (M+H)+. 3-(5-{7-[2-(1-tert-Butoxycarbonyl-pyrrolidin-2-yl)-3H-imidazol-4-yl]-9,10-dihydro-phenanthren-2-yl}-1H-imidazol-2-yl)-2-aza-bicyclo[2.2.1]heptane-2-carboxylic acid tert-butyl ester. A mixture of 2-aza-bicyclo[2.2.1]heptane-2,3-dicarboxylic acid 3-(2-{7-[2-(1-tert-butoxycarbonyl-pyrrolidine-2-carbonyloxy)-acetyl]-9,10-dihydro-phenanthren-2-yl}-2-oxo-ethyl)ester 2-tert-butyl ester (171 mg, 0.24 mmol) and ammonium acetate (800 mg, 10.2 mmol) in xylene (5 mL) was heated in a sealed tube at 140° C. for 1.5 hours under microwave condition. The volatile component was removed in vacuo, and the residue was dissolved in ethyl acetate (100 mL), washed with NaHCO3 solution, water and brine, dried over Na2SO4, filtered and concentrated in vacuo. The obtained residue was purified by flash chromatography to provide the desired product of 3-(5-{7-[2-(1-tert-butoxycarbonyl-pyrrolidin-2-yl)-3H-imidazol-4-yl]-9,10-dihydro-phenanthren-2-yl}-1H-imidazol-2-yl)-2-aza-bicyclo[2.2.1]heptane-2-carboxylic acid tert-butyl ester as a white solid (100 mg, 62%). m/z 677.9 (M+H)+. (1-{3-[5-(7-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-9,10-dihydro-phenanthren-2-yl)-1H-imidazol-2-yl]-2-aza-bicyclo[2.2.1]heptane-2-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester. To a solution of 3-(5-{7-[2-(1-tert-butoxycarbonyl-pyrrolidin-2-yl)-3H-imidazol-4-yl]-9,10-dihydro-phenanthren-2-yl}-1H-imidazol-2-yl)-2-aza-bicyclo[2.2.1]heptane-2-carboxylic acid tert-butyl ester (100 mg, 0.15 mmol) in methanol (5 mL) was added 4.0 M solution of HCl in dioxane (2 mL, excess). The mixture was stirred for 3 hours at 50° C. and concentated under reduced pressure. The residue was treated with ether to remove excess HCl. The obtained white solid was dissoved in DMF (5 mL), to the solution was added 2-methoxycarbonylamino-3-methyl-butyric acid (54 mg, 0.31 mmol), HATU (141 mg, 0.37 mmol) and N,N-diisopropylethylamine (0.2 mL, 1.2 mmol). The mixture was stirred at ambient for 2 hours, and then the volatile component was removed in vacuo. The residue was dissolved in ethyl acetate (100 mL), washed with 1 N NaOH solution, water and brine, dried over Na2SO4, filtered and concentrated in vacuo. The obtained residue was purified by HPLC to provide the desired product (1-{3-[5-(7-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-9,10-dihydro-phenanthren-2-yl)-1H-imidazol-2-yl]-2-aza-bicyclo[2.2.1]heptane-2-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester as TFA salt (67 mg, 57%). 1H-NMR (300 MHz, CD3OD) 8.05-7.65 (m, 8H), 5.35-5.20 (m, 1H), 4.40-4.05 (m, 3H), 3.95-3.80 (m, 1H), 3.67 (d, 6H), 3.05-2.80 (m, 5H), 2.70-2.50 (m, 1H), 2.40-1.60 (m, 13H), 1.10-0.85 (m, 12H); m/z 791.3 (M+H)+.
