1-Hydroxybenzotriazole → HCID 68929484, compound

Participants

Reaction Steps

6-[(tert-Butoxycarbonyl)amino]hexanoic acid (6.81 g, 29.5 mmol), 1-hydroxybenzotriazole (3.98 g, 29.5 mmol), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) (5.66 g, 29.5 mmol) were added to a 0° C. solution of 2-[2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]-1,1-dimethylethylamine (which was prepared by acid-mediated deprotection of tert-butyl 2-[2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]-1,1-dimethylethylcarbamate, which is described in U.S. Patent Publication No. 2004/0091491, 8.00 g, 26.8 mmol) in DMF (80 mL). The solution was stirred at room temperature overnight. More 6-[(tert-butoxycarbonyl)amino]hexanoic acid and EDC were added and the solution was stirred for an additional hour. The solution was partitioned between aqueous sodium bicarbonate and ethyl acetate. The aqueous layer was extracted with ethyl acetate (2×). The organic layers were combined, washed with water and brine, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by chromatography on silica gel to provide 3.99 g of tert-butyl 6-({2-[2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]-1,1-dimethylethyl}amino)-6-oxohexylcarbamate as a foam.

Provenance & Evidence