Dichloromethane → 1-(4-amino-7-bromo-1H-imidazo[4,5-c]quinolin-1-yl)-2-methylpropan-2-ol

Participants

Reaction Steps

A 1-liter round bottom flask was charged with 1-(7-bromo-1H-imidazo[4,5-c]quinolin-1-yl)-2-methylpropan-2-ol (25.0 g, 78.0 mmol), dichloromethane (400 mL) and chloroform (100 mL). To this solution was slowly added in small portions 3-chloroperoxybenxzoic acid (34.0 g of 60% purity, 117 mmol, 1.5 eq). The reaction was maintained at room temperature for 2 hours and then concentrated ammonium hydroxide solution (200 mL) was added. The mixture was vigorously stirred as p-toluenesulfonyl chloride (22.4 g, 117 mmol) was slowly added in small portions. The reaction was complete within 1 hour but was left to stir at room temperature overnight. The reaction mixture was filtered to collect a pale yellow solid. The product was purified by chromatography using a HORIZON HPFC system (silica cartridge, eluting with 0-30% CMA in chloroform). The resulting pale yellow solid was slurried in cold acetonitrile, isolated by filtration, and air-dried on the vacuum filter to provide 17.2 g of 1-(4-amino-7-bromo-1H-imidazo[4,5-c]quinolin-1-yl)-2-methylpropan-2-ol. The filtrate was transferred to a separatory funnel and the layers were separated. The aqueous layer was extracted with chloroform (3×100 mL). The chloroform fractions were combined, washed with brine (100 mL), dried over magnesium sulfate and concentrated to dryness to provide an additional 0.8 g of 1-(4-amino-7-bromo-1H-imidazo[4,5-c]quinolin-1-yl)-2-methylpropan-2-ol, mp>250° C.

Provenance & Evidence