Thionyl Chloride → 2-cyclopropyl-N-(6-iodoimidazo[1,2-b]pyridazin-2-yl)acetamide

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Reaction Steps

To a solution of cyclopropylacetic acid (441 mg, 4.4 mmol) in tetrahydrofuran (8.0 mL) were added N,N-dimethylformamide (1 drop) and thionyl chloride (0.32 mL, 4.4 mmol), and the mixture was stirred at room temperature for 2 hr. The reaction mixture was concentrated under reduced pressure, and dissolved in N,N-dimethylacetamide (2.0 mL). To a solution of 6-iodoimidazo[1,2-b]pyridazin-2-amine (1.04 g, 4.0 mmol) in N,N-dimethylacetamide (6.0 mL) was added dropwise the above-mentioned solution under ice-cooling. The mixture was stirred at room temperature for 2 hr. Under ice-cooling, aqueous sodium hydrogencarbonate solution was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over anhydrous magnesium sulfate, and filtrated. The solvent was evaporated under reduced pressure, and the residue was purified by basic silica gel column chromatography (ethyl acetate/hexane=80/20→100/0), and recrystallized from ethyl acetate to give the title compound (982 mg, 72%) as pale-green crystals.

Provenance & Evidence