4-Toluenesulfonyl chloride → 7-benzyloxy-2-ethoxymethyl-N-isopropyl-1H-imidazo[4,5-c]quinoline-1,4-diamine

Participants

Reaction Steps

A solution of N-(7-benzyloxy-2-ethoxymethyl-1H-imidazo[4,5-c]quinolin-1-yl)isopropylamine (6.63 g, 17.0 mmol) in 90 mL of CHCl3 was treated with MPCBA (6.29 g, 25.5 mmol, 70%). After 3 h, HPLC and LC/MS indicated complete conversion to the intermediate 5-N-oxide. The reaction mixture was then treated with concentrated ammonium hydroxide solution (30 mL, 30%). The biphasic reaction mixture was stirred vigorously while p-toluenesulfonyl chloride (3.40 g, 17.9 mmol) was added. After 45 min, LC/MS indicated complete conversion to the 4-amine. The reaction mixture was diluted with 30 mL of water and 45 mL of CHCl3 and separated. The organic portion was washed with 10% Na2CO3 solution (50 mL) and water (50 mL). The combined aqueous portions were then back-extracted with CHCl3 (25 mL). The combined organic portions were washed with brine (50 mL), dried over Na2SO4, filtered and concentrated to yield a tan solid. The solid was purified by chromatography (SiO2, 96:4 CHCl3:MeOH) to give 5.90 g of 7-benzyloxy-2-ethoxymethyl-N1-isopropyl-1H-imidazo[4,5-c]quinoline-1,4-diamine as a light tan solid.

Provenance & Evidence