Sodium hydride → (1-{2-[5-(4-bromo-phenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl)-2-methyl-propyl)-carbamic acid methyl ester

Participants

Reaction Steps

(1-{2-[5-(4-Bromo-phenyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (2.6 g, 5.8 mmol) in DMF (60 mL) was treated with NaH (60% dispersion in mineral oil, 256 mg, 6.4 mmol) in one portion. After 5 min, the mixture was treated with SEMCl (1.08 mL, 6.1 mmol) in 0.1 mL portions over 10 min. The reaction was stirred for 2 hours and diluted with saturated NH4C1 solution (50 mL) and EtOAc (100 mL). The organic layer was washed with H2O (3 50 mL) and brine (50 mL). The solution was dried over MgSO4 and subjected to a 120 g SiO2 COMBIFLASH column (0-100% EtOAc-hexanes gradient) to afford (1-{2-[5-(4-bromo-phenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (2.4 g, 71%). {1-[2-(5-{4-[4-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-(2-trimethylsilanyl-ethoxymethyl)-3H-imidazol-4-yl}-phenyl)-piperazin-1-yl]-phenyl}-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl)-pyrrolidine-1-carbonyl]-2-methyl-propyl}-carbamic acid methyl ester: (1-{2-[5-(4-Bromo-phenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (222 mg, 0.38 mmol) and piperazine (17 mg, 0.19 mmol) in toluene (3.5 mL) were treated with Pd(OAc)2 (2.1 mg, 0.0096 mmol, via 10% solution in toluene), BINAP (12 mg, 0.019 mmol), and NaOtBu (64 mg, 0.67 mmol). The mixture was stirred in a sealed tube at 120° C. for 4 hours. The solution was concentrated, diluted with EtOAc (50 mL), and washed with saturated NaHCO3 (20 mL), H2O (20 mL), and brine (20 mL). The solution was dried over MgSO4 and subjected to a reverse phase HPLC column (5-95% MeCN—H2O; 0.1% TFA modifier) to afford {1-[2-(5-{4-[4-(4-{2-[1-(2-methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-(2-trimethylsilanyl-ethoxymethyl)-3H-imidazol-4-yl}-phenyl)-piperazin-1-yl]-phenyl}-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl)-pyrrolidine-1-carbonyl]-2-methyl-propyl}-carbamic acid methyl ester (8 mg, 4%): MS (ESI) m/z 1105 [M+Na]+. {1-[2-(5-{4-[4-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-phenyl)-piperazin-1-yl]-phenyl}-1H-imidazol-2-yl)-pyrrolidine-1-carbonyl]-2-methyl-propyl}-carbamic acid methyl ester: {1-[2-(5-{4-[4-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-(2-trimethylsilanyl-ethoxymethyl)-3H-imidazol-4-yl}-phenyl)-piperazin-1-yl]-phenyl}-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl)-pyrrolidine-1-carbonyl]-2-methyl-propyl}-carbamic acid methyl ester (8 mg, 0.007 mmol) in trifluoroacetic acid (1.0 mL) was stirred in a screw-cap vial at 40° C. for 1 hours. The solution was concentrated and subjected to a reverse phase HPLC column (5-95% MeCN—H2O; 0.1% TFA modifier) to afford {1-[2-(5-{4-[4-(4-{2-[1-(2-methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-phenyl)-piperazin-1-yl]-phenyl 1-1H-imidazol-2-yl)-pyrrolidine-1-carbonyl]-2-methyl-propyl}-carbamic acid methyl ester (1.9 mg, 32%) as a white solid (TFA salt): 1H NMR (CD3OD, 300 MHz) 7.66 (s, 2H), 7.60 (d, J=8.7 Hz, 4H), 7.13 (d, J=8.7 Hz, 4H), 5.21 (app t, J=8.1 Hz, 2H), 4.22 (d, J=7.2 Hz, 2H), 4.09 (m, 2H), 3.85 (m, 2H), 3.66 (s, 6H), 3.31 (m, 5H), 2.52 (m, 2H), 2.16 (m, 8H), 0.91 (m, 12H); MS (ESI) m/z 824 [M+H]+.

Provenance & Evidence