3-Pyridine aldoxime → 4-chloro-2-(ethoxymethyl)-1-[(3-pyridin-3-ylisoxazol-5-yl)methyl]-1H-imidazo[4,5-c]quinoline

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Reaction Conditions

Reaction Steps

N-Chlorosuccinimide (1.09 g, 8.19 mmol) was added to a 6° C. solution of 3-pyridinecarboxaldehyde oxime (1.00 g, 8.19 mmol) in tetrahydrofuran (THF) (25 mL). The solution was heated at 50° C. for 2 h. 4-Chloro-2-(ethoxymethyl)-1-prop-2-ynyl-1H-imidazo[4,5-c]quinoline (prepared as described in Part D of Example 3, 1.96 g, 6.55 mmol) and triethylamine (1.70 mL, 12.3 mmol) were added to the reaction, which was heated at 50° C. for 17 hours. The volatiles were removed under reduced pressure and the residue was partitioned between dichloromethane and saturated aqueous potassium carbonate. The aqueous layer was extracted multiple times with dichloromethane and chloroform. The organic layers were combined, dried over sodium sulfate, filtered, and concentrated. The crude product was purified by flash chromatography (silica gel, gradient elution with 1:1 to 1:4 hexanes/ethyl acetate) to yield 4-chloro-2-(ethoxymethyl)-1-[(3-pyridin-3-ylisoxazol-5-yl)methyl]-1H-imidazo[4,5-c]quinoline (1.52 g).

Provenance & Evidence