Oxalyl chloride → 1,3-dimethyl-N-{2-methyl-5-[(2-{[(1-methylcyclopropyl)carbonyl]amino}imidazo[1,2-b]pyridazin-6-yl)oxy]phenyl}-1H-pyrazole-5-carboxamide

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Reaction Steps

To a solution of 1-methylcyclopropanecarboxylic acid (97 mg, 0.97 mmol) in tetrahydrofuran (1.5 mL) were added N,N-dimethylformamide (1 drop) and oxalyl chloride (83 μL, 0.97 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-methylphenyl}-1,3-dimethyl-1H-pyrazole-5-carboxamide hydrochloride (200 mg, 0.48 mmol) in N,N-dimethylacetamide (5 mL), and the mixture was stirred at room temperature for 1 hr. Ethyl acetate/tetrahydrofuran and saturated aqueous sodium hydrogencarbonate solution were added to the mixture, and the aqueous layer was extracted with ethyl acetate/tetrahydrofuran (×4). Combined organic layer was washed with water and saturated brine, dried over anhydrous sodium sulfate, and filtrated. The filtrate was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (ethyl acetate/hexane=30/70→100/0) to give the title compound (105 mg, 74%) as a white solid.

Provenance & Evidence