Boron tribromide → {4-amino-1-[2,2-dimethyl-3-(methylsulfonyl)propyl]-1H-imidazo[4,5-c]quinolin-2-yl}methanol

Participants

Reaction Steps

To a suspension of 1-[2,2-dimethyl-3-(methylsulfonyl)propyl]-2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-4-amine (0.4 g, 1.02 mmol) in dichloromethane (5 mL) was added boron tribromide (5.1 mL, 1M solution in dichloromethane). An exotherm was observed upon addition and the mixture turned light purple. After stirring at ambient temperature for 20 hours, the remaining starting material was consumed by adding boron tribromide (2.5 mL, 1M solution in dichloromethane). The reaction was quenched with aqueous hydrochloric acid (1N, 20 mL) to afford a homogeneous mixture. The layers were separated and the aqueous layer washed with dichloromethane (20 mL). The pH of the aqueous layer was adjusted to 12 by addition of aqueous sodium hydroxide (50%) at which time a solid precipitated out of solution. The solid was stirred for 18 hours, collected by filtration and washed with water. The crude product was purified by chromatography over silica gel (eluting with CMA) to afford a white powder. The powder was triturated with methanol (20 mL). The resulting solid was isolated by filtration, washed with methanol and dried for 4 hours at 65° C. to provide 150 mg of {4-amino-1-[2,2-dimethyl-3-(methylsulfonyl)propyl]-1H-imidazo[4,5-c]quinolin-2-yl}methanol as a white powder, mp 230-232° C.

Provenance & Evidence