Dimethyl Sulfoxide → 3-[2-(3-Oxocyclohexyl)-3-oxo-2,3-dihydropyridazin-6-yl]-2-phenylpyrazolo[1,5-a]pyridine

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Reaction Steps

To a solution of oxalyl chloride (160 μl) in dichloromethane (10 ml) was added dropwise in turn with dimethyl sulfoxide (210 μl), a solution of 3-[2-(3-hydroxycyclohexyl)-3-oxo-2,3-dihydropyridazin-6-yl]-2-phenylpyrazolo[1,5-a]pyridine (366 mg) in dichloromethane (10 ml) and triethylamine (663 μl) at -70° C. under nitrogen atmosphere. A reaction mixture was allowed to warm to ambient temperature and diluted with ethyl acetate (100 ml), which was washed in turn with 1N-aqueous hydrochloric acid (50 ml×2), brine (50 ml), saturated sodium hydrogen carbonate in water (50 ml) and brine (50 ml×2), and dried over magnesium sulfate. Evaporation of the solvent gave a residue, which was chromatographed on silica gel eluting in turn with 30% and 50% ethyl acetate in dichloromethane. Fractions containing desired product were combined and concentrated in vacuo to give solid, which was recrystallized from ethanol to give 3-[2-(3-oxocyclohexyl)-3-oxo-2,3-dihydropyridazin-6-yl]-2-phenylpyrazolo[1,5-a]pyridine (310 mg).

Provenance & Evidence