4-Toluenesulfonyl chloride → HCID 58837345, compound

Participants

Reaction Steps

To a stirred solution of ethyl 4-[2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]butanoate (15.4 g, 45.1 mmol) in dichloromethane (150 mL) at 0° C. was added mCPBA (approximately 77% purity, 19.7 g, 87.9 mmol) in portions. The reaction mixture was stirred at room temperature for 1.5 hours, then concentrated ammonium hydroxide (50 mL) was added. p-Toluenesulfonyl chloride was added in portions to the mixture, which was stirred for 1 hour then filtered. The filtrate was transferred to a separatory funnel, saturated aqueous sodium bicarbonate (50 mL) was added and the layers were separated. The aqueous layer was extracted with dichloromethane (2×50 mL). The organic layers were combined, washed with 5% aqueous sodium hydroxide (2×75 mL), dried over potassium carbonate, filtered, and concentrated under reduced pressure to yield a brown solid that was slurried in ethyl acetate (50 mL) and filtered. The filtrate was concentrated under reduced pressure and the solid was recrystallized from ethanol/water four times, then was dissolved in dichloromethane (100 mL). The solution was washed with saturated aqueous sodium bicarbonate (2×50 mL), then was concentrated under reduced pressure to yield a solid that was recrystallized from ethanol/water three times. The crystals were dried in a vacuum oven at 70° C. to provide ethyl 4-[4-amino-2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]butanoate as pale yellow crystals, mp 129-131° C.

Provenance & Evidence