Boron tribromide → N-{3-[4-amino-2-(2-hydroxyethyl)-1H-imidazo[4,5-c]quinolin-1-yl]propyl}-4-methylbenzenesulfonamide

Participants

Reaction Conditions

Reaction Steps

Boron tribromide (5.50 mL of 1 M in dichloromethane) was added dropwise to a chilled (0° C.) suspension of N-{3-[4-amino-2-(2-methoxyethyl)-1H-imidazo[4,5-c]quinolin-1-yl]propyl}-4-methylbenzenesulfonamide (1.0 g, 2.2 mmol; U.S. Pat. No. 6,677,349, Example 253) in dichloromethane (20 mL). The reaction mixture was stirred at 0° C. for 3 hours. The reaction mixture was quenched with methanol. Hydrochloric acid (about 10 mL of 6 N) was added and the mixture was stirred at 50° C. overnight. The mixture was diluted with water (50 mL) and ethyl acetate (100 mL) and then brought to neutral pH with solid sodium hydroxide. The layers were separated and the aqueous was extracted with ethyl acetate (×2). The combined organics were dried over magnesium sulfate, filtered, and then concentrated under reduced pressure to provide a yellow solid. This material was purified by prep HPLC (COMBIFLASH system eluting first with a gradient of 0 to 5% methanol in dichloromethane containing 1% ammonium hydroxide and then with a gradient of 5 to 10% methanol in dichloromethane containing 1% ammonium hydroxide) to provide a white solid. This material was suspended in hot acetonitrile, allowed to cool, and then the solvent was decanted. The resulting material was dried under vacuum to provide about 200 mg of N-{3-[4-amino-2-(2-hydroxyethyl)-1H-imidazo[4,5-c]quinolin-1-yl]propyl}-4-methylbenzenesulfonamide as a white solid, m.p. 231-232° C. Anal, calcd for C22H25N5O3S.0.20 CH4O: % C, 59.79; % H, 5.85; % N, 15.70. Found: % C, 59.44; % H, 5.89; % N, 15.52.

Provenance & Evidence