Thionyl Chloride → N-[5-({2-[(cyclopropylcarbonyl)amino]imidazo[1,2-b]pyridazin-6-yl}oxy)-2-fluorophenyl]-1,4-dimethyl-1H-pyrazole-3-carboxamide

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Reaction Steps

To a suspension of 1,4-dimethyl-1H-pyrazole-3-carboxylic acid (151 mg, 1.08 mmol) in tetrahydrofuran (2.0 mL) were added N,N-dimethylformamide (1 drop) and thionyl chloride (0.08 mL, 1.1 mmol), and the mixture was stirred at room temperature for 50 min. The reaction mixture was concentrated under reduced pressure and dissolved in N,N-dimethylacetamide (2.0 mL). On the other hand, to a solution of N-[6-(3-amino-4-fluorophenoxy)imidazo[1,2-b]pyridazin-2-yl]cyclopropanecarboxamide (327 mg, 1.0 mmol) in N,N-dimethylacetamide (6.0 mL) was added dropwise the above-mentioned solution under ice-cooling, and 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 tetrahydrofuran/ethanol to give the title compound (283 mg, 63%) as pale-yellow crystals.

Provenance & Evidence