Binap, (A+-)- → 4-{4-[2-[1-(2-methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3-(2-trimethylsilanyl-ethoxymethyl)-3H-imidazol-4-yl]-phenyl]-piperazine-1-carboxylic acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

(1-{2-[5-(4-Bromo-phenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (1033 mg, 1.8 mmol) and 4-Cbz-piperazine (588 mg, 2.7 mmol) in toluene (9 mL) were treated with Pd(OAc)2 (20 mg, 0.09 mmol), BINAP (110 mg, 0.1 mmol), and NaOtBu (428 mg, 4.45 mmol). The mixture was stirred in a sealed tube at 110° C. for 18 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 120 g SiO2 COMBIFLASH column (0-100% EtOAc-hexanes gradient) to afford 4-{4-[2-[1-(2-methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3-(2-trimethylsilanyl-ethoxymethyl)-3H-imidazol-4-yl]-phenyl}-piperazine-1-carboxylic acid benzyl ester (166 mg, 13%): MS (ESI) m/z 719 [M+H]+. (2-Methyl-1-{2-[5-(4-piperazin-1-yl-phenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-propyl)-carbamic acid methyl ester: 4-{4-[2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3-(2-trimethylsilanyl-ethoxymethyl)-3H-imidazol-4-yl]-phenyl}-piperazine-1-carboxylic acid benzyl ester (166 mg, 0.23 mmol) in EtOH (2.5 mL) was treated with 20% PdOH/C (60 mg) and placed under an atmosphere of H2. The reaction was stirred for 18 hours and filtered through a CELITE plug to afford crude (2-methyl-1-{2-[5-(4-piperazin-1-yl-phenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-propyl)-carbamic acid methyl ester (120 mg), which was used without further purification: MS (ESI) m/z 585 [M+H]+. 2-[4-[4-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3-methyl-3H-imidazol-4-yl}-phenyl)-piperazine-1-carbonyl]-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carboxylic acid tert-butyl ester: (2-Methyl-1-{2-[5-(4-piperazin-1-yl-phenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-propyl)-carbamic acid methyl ester (28 mg, 0.047 mmol) and 2-(1-tert-butoxycarbonyl-pyrrolidin-2-yl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazole-4-carboxylic acid (20 mg, 0.047 mmol) in DMF (1 mL) were treated with HATU (20 mg, 0.052 mmol) and N-methyl morpholine (0.26 mL, 0.23 mmol). The mixture was stirred for 18 hours then diluted with EtOAc (25 mL), and washed with saturated NaHCO3 (3 10 mL), H2O (10 mL), and brine (10 mL). The solution was dried over MgSO4 to afford crude 2-[4-[4-(4-{2-[1-(2-methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3-methyl-3H-imidazol-4-yl}-phenyl)-piperazine-1-carbonyl]-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carboxylic acid tert-butyl ester, which was used without further purification: MS (ESI) m/z 978 [M+H]+. [1-(2-{5-[4-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazole-4-carbonyl}-piperazin-1-yl)-phenyl]-1H-imidazol-2-yl}-pyrrolidine-1-carbonyl)-2-methyl-propyl]-carbamic acid methyl ester: 2-[4-[4-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3-methyl-3H-imidazol-4-yl}-phenyl)-piperazine-1-carbonyl]-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazol-2-yl]-pyrrolidine-1-carboxylic acid tert-butyl ester (47 mg, 0.05 mmol) in trifluoroacetic acid (3.0 mL) was stirred for 18 hours. The mixture was concentrated, suspended in DMF (1.5 mL), and treated with (S)-Moc-Val-OH (9 mg, 0.0.053 mmol), HATU (20 mg, 0.0.053 mmol), and N-methyl morpholine (0.26 mL, 0.24 mmol). The mixture was stirred for 18 hours then diluted with EtOAc (25 mL), and washed with saturated NaHCO3 (3 10 mL), H2O (10 mL), and brine (10 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-{2-[1-(2-methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazole-4-carbonyl}-piperazin-1-yl)-phenyl]-1H-imidazol-2-yl}-pyrrolidine-1-carbonyl)-2-methyl-propyl]-carbamic acid methyl ester (6.6 mg, 18%) as a white solid (TFA salt): 1H NMR (CD3OD, 300 MHz) 7.67 (s, 2H), 7.59 (d, J=8.7 Hz, 2H), 7.10 (d, J=9.3 Hz, 2H), 5.20 (app t, J=7.2 Hz, 2H), 4.22 (d, J=7.2 Hz, 2H), 4.01 (m, 5H), 3.85 (m, 2H), 3.66 (s, 6H), 3.38 (m, 2H), 2.52 (m, 2H), 2.16 (m, 8H), 0.91 (m, 12H); MS (ESI) m/z 775 [M+H]+.

Provenance & Evidence