4-Toluenesulfonyl chloride → 2-ethoxymethyl-1-(3-isopropoxypropyl)-7-[(E)-2-(phenylsulfonyl)ethenyl]-1H-imidazo[4,5-c]quinolin-4-amine

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Reaction Steps

7-(2-Benzenesulfonylvinyl)-2-ethoxymethyl-1-(3-isopropoxypropyl)-1H-imidazo[4,5-c]quinoline (0.600 g, 1.22 mmol) was dissolved in chloroform (12 mL). 3-Chloroperoxybenzoic acid (60% purity, 0.351 g, 1.22 mmol) was added. The reaction was stirred for 30 minutes. Ammonium hydroxide (8 mL) was added and the mixture was stirred for 10 minutes. p-Toluenesulfonyl chloride (0.232 g, 1.22 mmol) was added in one portion and the reaction was stirred for an additional 16 hours. The layers were separated and the aqueous fraction was extracted with chloroform. The combined organic fractions were sequentially washed with water and saturated aqueous sodium chloride, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography using a Horizon HPFC system (an automated, modular high-performance flash purification product available from Biotage, Inc.; Charlottesville, Va., USA). The polar component of the eluent was chloroform:methanol:ammonium hydroxide 80:18:2 (CMA). The purification was carried out with a silica cartridge eluting with a linear gradient of 1-22% CMA in chloroform. The resulting material was subsequently recrystallized from acetonitrile to yield 0.320 g 2-ethoxymethyl-1-(3-isopropoxypropyl)-7-[(E)-2-(phenylsulfonyl)ethenyl]-1H-imidazo[4,5-c]quinolin-4-amine as green needles, mp 188.5-190.0° C.

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