Dimethylformamide → N-{2-fluoro-5-[(2-{[(2,2,3,3-tetramethylcyclopropyl)carbonyl]amino}imidazo[1,2-b]pyridazin-6-yl)oxy]phenyl}-1,3-dimethyl-1H-pyrazole-5-carboxamide

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Reaction Steps

To a solution of 2,2,3,3-tetramethylcyclopropanecarboxylic acid (102 mg, 0.72 mmol) in tetrahydrofuran (4.0 mL) were added N,N-dimethylformamide (20 μL, 0.26 mmol) and oxalyl chloride (63 mL, 0.72 mmol), and the mixture was stirred at room temperature for 30 min. The reaction mixture was added to a solution of N-{5-[(2-aminoimidazo[1,2-b]pyridazin-6-yl)oxy]-2-fluorophenyl}-1,3-dimethyl-1H-pyrazole-5-carboxamide.hydrochloride (200 mg, 0.48 mmol) in N,N-dimethylacetamide (4.0 mL), and the mixture was stirred at room temperature for 3 hr. Saturated aqueous sodium hydrogencarbonate solution was added to the reaction mixture, and the mixture was extracted with ethyl acetate/tetrahydrofuran, washed with saturated brine, dried over anhydrous sodium sulfate, and filtrated. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (ethyl acetate/hexane=3/1) and precipitated from hexane/ethyl acetate to give the title compound (46 mg, 19%) as a white powder.

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