Methanol → Ammonia methanol

Participants

Reaction Steps

Mix 5-[2-tert-butyl-5-(2,4-difluoro-phenyl)-1H-imidazol-4-yl]-3-(2,2-dimethyl-propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine (11.55 g, 26.33 mmol) in MeOH (150 mL), and then add a solution of methanesulfonic acid (2.53 g, 26.33 mmol) in MeOH (10 mL) dropwise. Stir the resulting reaction mixture at room temperature for 20 minutes, then concentrate under reduced pressure. Slurry the residue in Et2O, then filter and wash with fresh Et2O. Dry the resulting solid in a drying oven at room temperature under house vacuum overnight, then at 80° C. for 1.5 h. Dissolve the salt in MeOH and then treat with NaHCO3 until basic. Extract the resulting solution with EtOAc, dry the combined organics over Na2SO4, filter, then concentrate under reduced pressure. Purify by column chromatography, eluting with neat EtOAc, then 1% of 2N ammonia/MeOH in EtOAc, then 2% of 2N ammonia/MeOH in EtOAc to give 9.38 g of 5-[2-tert-butyl-5-(2,4-difluoro-phenyl)-1H-imidazol-4-yl]-3-(2,2-dimethyl-propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine. Mix 5-[2-tert-butyl-5-(2,4-difluoro-phenyl)-1H-imidazol-4-yl]-3-(2,2-dimethyl-propyl)-3H-imidazo[4,5-b]pyridin-2-ylamine (9.38 g, 21.39 mmol) in anhydrous MeOH (150 mL), and then add a solution of methanesulfonic acid (2.06 g, 21.43 mmol) in MeOH (10 mL) dropwise. Allow the resulting reaction mixture to stir at room temperature for 30 minutes, then concentrate under reduced pressure. Slurry the residue in Et2O, then filter and wash with fresh Et2O. Dry the resulting solid in a drying oven at room temperature under house vacuum for 48 h to give 10.695 g (76% yield) of the title compound as a tan solid.

Provenance & Evidence