4-Toluenesulfonyl chloride → tert-butyl 2-[(4-amino-2-ethoxymethyl-1-propyl-1H-imidazo[4,5-c]quinolin-8-yl)oxy]ethylcarbamate

Participants

Reaction Steps

Ammonium hydroxide (50 mL) was added to a solution of tert-butyl 2-[(2-ethoxymethyl-5-oxido-1-propyl-1H-imidazo[4,5-c]quinolin-8-yl)oxy]ethylcarbamate (9.7 g, 22 mmol) in dichloromethane (120 mL), and the mixture was cooled to 10° C. p-Toluenesulfonyl chloride (4.16 g, 21.8 mmol) was added in small portions, while maintaining the reaction temperature below 15° C. The reaction was stirred for 16 hours; a tan precipitate formed. Dichloromethane (500 mL) was added, and the precipitate was isolated by filtration and washed with diethyl ether to provide 3.98 g of tert-butyl[2-(4-amino-2-ethoxymethyl-1-propyl-1H-imidazo[4,5-c]quinolin-8-yloxy)ethyl]carbamate as a fine powder. The organic layer was washed sequentially with ammonium hydroxide, water, and brine, dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting solid was recrystallized from acetonitrile to provide 4.4 g of tert-butyl 2-[(4-amino-2-ethoxymethyl-1-propyl-1H-imidazo[4,5-c]quinolin-8-yl)oxy]ethylcarbamate as a peach-colored powder.

Provenance & Evidence