Potassium Carbonate → Tert-butyl 2-azabicyclo[2.2.1]heptane-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of 245-(4-Bromo-phenyl)-1H-imidazol-2-yl]-pyrrolidine-1-carboxylic acid tert-butyl ester (1.079 g, 2.737 mmol), Naphthalene-2,6-diboronic acid dominical ester (5 eq., 5.2 g, 13.68 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (5%, 96 mg), tetrakis(triphenylphosphine)palladium (5%, 158 mg) and potassium carbonate (5 eq., 757 mg) in 40 mL DME and 10 mL water was heated to 110° C. under Argon for 2 hours. The reaction mixture was cooled and diluted with ethyl acetate and washed with saturated sodium bicarbonate solution. The organic layer dried (MgSO4), concentrated and purified by flash column chromatography (silica gel, 20 to 100% ethyl acetate/hexane) to give 2-(5-{4-[6-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-naphthalen-2-yl]-phenyl}-1H-imidazol-2-yl)-pyrrolidine-1-carboxylic acid tert-butyl ester (730 mg, yield 47%). LCMS-ESI−: calc'd for C34H4OBN3O4: 565.51. Found: 566.1 (M+H+). 3-[6-(6-{4-[2-(1-tert-Butoxycarbonyl-pyrrolidin-2-yl)-3H-imidazol-4-yl]-phenyl}-naphthalen-2-yl)-1H-benzoimidazol-2-yl]-2-aza-bicyclo[2.2.1]heptane-2-carboxylic acid tert-butyl ester: A mixture of 2-(5-{4-[6-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-naphthalen-2-yl]-phenyl}-1H-imidazol-2-yl)-pyrrolidine-1-carboxylic acid tert-butyl ester (216 mg, 0.382 mmol), 3-(6-Bromo-1H-benzoimidazol-2-yl)-2-aza-bicyclo[2.2.1]heptane-2-carboxylic acid tert-butyl ester (1 eq., 150 mg, 0.382 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (5%, 16 mg), tetrakis(triphenylphosphine)palladium (5%, 22 mg) and potassium carbonate (2 eq., 106 mg) in 4 mL DME and 1 mL water was heated to 90° C. under Argon for 5 hours. The reaction mixture was cooled and diluted in ethyl acetate and washed with saturated sodium bicarbonate solution. The organic layer dried (MgSO4), concentrated and purified by flash column chromatography (silica gel, 20 to 100% ethyl acetate/hexane) to give 346-(6-{4-[2-(1-tert-Butoxycarbonyl-pyrrolidin-2-yl)-3H-imidazol-4-yl]-phenyl}-naphthalen-2-yl)-1H-benzoimidazol-2-yl]-2-aza-bicyclo[2.2.1]heptane-2-carboxylic acid tert-butyl ester (100 mg, yield 35%). LCMS-ESI−: calc'd for C46H50N6O4: 750.93. Found: 751.2 (M+H+). [1-(3-{6-[6-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-phenyl)-naphthalen-2-yl]-1H-benzoimidazol-2-yl}-2-aza-bicyclo[2.2.1]heptane-2-carbonyl)-2-methyl-propyl]-carbamic acid methyl ester (Example DM): TFA (2 mL) was added to 346-(6-{4-[2-(1-tert-Butoxycarbonyl-pyrrolidin-2-yl)-3H-imidazol-4-yl]-phenyl}-naphthalen-2-yl)-1H-benzoimidazol-2-yl]-2-aza-bicyclo[2.2.1]heptane-2-carboxylic acid tert-butyl ester (100 mg, 0133 mmol) and the reaction mixture was stirred at room temperature for 2 hours. The reaction mixture was concentrated and dried overnight under vacuum. The residue was dissolved in DMF (2 mL) and to this solution was added 2-Methoxycarbonylamino-3-methyl-butyric acid (2 eq., 47 mg), diisopropyl ethylamine (6 eq., 0.14 mL), followed by HATU (2 eq., 101 mg). Reaction mixture was stirred at 0° C. for 30 minutes. The reaction mixture was diluted in ethyl acetate and washed with saturated sodium bicarbonate solution. The organic layer was dried (MgSO4), concentrated and purified by preparative reverse phase HPLC (GEMINI, 5 to 100% ACN/H2O+0.1% TFA). Product was lyophilized to give [1-(3-{6-[6-(4-{2-[1-(2-Methoxycarbonylamino-3-methyl-butyryl)-pyrrolidin-2-yl]-3H-imidazol-4-yl}-phenyl)-naphthalen-2-yl]-1H-benzoimidazol-2-yl}-2-aza-bicyclo[2.2.1]heptane-2-carbonyl)-2-methyl-propyl]-carbamic acid methyl ester (Example DM) (19.7 mg, 17%).

Provenance & Evidence