HCID 11152911, compound → HCID 57555838, compound

Participants

Reaction Steps

A stirring solution of N-{2-[4-amino-2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]ethyl}-N′-isopropylurea (400 mg, 1.1 mmol) in dichloromethane (50 mL) was sealed with a septum and purged with nitrogen gas. The solution was cooled in an ice/water bath and a 1.0 M solution of boron tribromide in dichloromethane (2.2 mL) was added via syringe. The resulting mixture was stirred for 2 hours while warming to ambient temperature. The mixture was cooled back to 0° C. in an ice/water bath and the second portion of boron tribromide (1.0 M, 5.5 mL) was added. The reaction was stirred for 18 hours while warming to ambient temperature. Aqueous hydrochloric acid (6N, 10 ml) was added and the mixture was stirred for 1 hour. The layers were separated and the aqueous fraction was neutralized by the slow addition of solid sodium hydroxide until the pH reached 14. A fine precipitate formed. The aqueous mixture was extracted with chloroform (2×50 mL) and filtered. The resulting solid (filter cake) was combined with the organic extracts, methanol (50 mL), and silica gel (5 g). The mixture was concentrated under reduced pressure. The crude product absorbed on silica was purified by chromatography using a HORIZON HPFC system (silica cartridge, eluting with 0-35% CMA in chloroform over 2.6 L) followed by recrystallization from acetonitrile to provide 170 mg of N-{2-[4-amino-2-(hydroxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]ethyl}-N′-isopropylurea as an off-white solid, mp>240° C.

Provenance & Evidence