Hydrogen chloride-ethyl acetate → 1-{4-fluoro-5-(2-fluoropyridin-3-yl)-1-[(3-methylpyridin-2-yl)sulfonyl]-1H-pyrrol-3-yl}-N-methylmethanamine

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Reaction Steps

To a solution of tert-butyl ({4-fluoro-5-(2-fluoropyridin-3-yl)-1-[(3-methylpyridin-2-yl)sulfonyl]-1H-pyrrol-3-yl}methyl)methylcarbamate (107 mg) in ethyl acetate (2 mL) and 2-propanol (1 mL) were added 4 mol/L hydrogen chloride-ethyl acetate solution (3 mL), and the mixture was stirred at room temperature for 1 hr. The reaction mixture was concentrated under reduced pressure, and the residue was diluted with saturated aqueous sodium hydrogen carbonate solution, and extracted with ethyl acetate. The separated aqueous layer was extracted again with ethyl acetate. Combined organic layers were washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified by basic silica gel column chromatography (eluent: hexane-ethyl acetate=4:11:1) to give 1-{4-fluoro-5-(2-fluoropyridin-3-yl)-1-[(3-methylpyridin-2-yl)sulfonyl]-1H-pyrrol-3-yl}-N-methylmethanamine as a pale-yellow oil (yield 45 mg, 54%). A solution of the obtained 1-{4-fluoro-5-(2-fluoropyridin-3-yl)-1-[(3-methylpyridin-2-yl)sulfonyl]-1H-pyrrol-3-yl}-N-methylmethanamine in ethyl acetate (2 mL) was added dropwise to a solution of fumaric acid (14 mg) in ethanol (2 mL) and the mixture was concentrated under reduced pressure. The residue was recrystallized from ethyl acetate-ethanol to give the title compound as a white solid (yield 51 mg, 88%).

Provenance & Evidence