Hydrochloric Acid → 4-[(2-ethoxymethyl-1H-imidazo[4,5-c]quinolin-1-yl)methyl]piperidin-4-ol

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Reaction Steps

To a solution of tert-butyl 4-{[2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]methyl}-4-hydroxypiperidine-1-carboxylate (prepared as described in Part E of Example 4, 14.94 g, 33.91 mmol) in ethanol (170 mL) was added a solution of HCl in ethanol (2.7 M, 31 mL, 84.7 mmol). The solution was heated at reflux for 1 h, during which time a precipitate formed. The mixture was allowed to cool to rt and the volatiles were removed under reduced pressure. To the residue was added water (400 mL) followed by 50% aqueous NaOH until the pH=10. The solution was extracted with dichloromethane (3×100 mL). The aqueous layer was treated with 50% aqueous NaOH until the pH=12, then was extracted with dichloromethane (2×100 mL). The organic layers were combined, dried over Na2SO4, filtered, and concentrated under reduced pressure. The resulting solid was triturated with hot ethyl acetate and the remaining solid was isolated by filtration to afford 4-{[2-(ethoxymethyl)-1H-imidazo[4,5-c]quinolin-1-yl]methyl}piperidin-4-ol (7.0 g, 61%) as an off-white powder.

Provenance & Evidence