Pyridine → 4-(1-cyclopentyl-4-oxo-4,5-dihydro-1H-pyrazolo[4,3-c]pyridin-3-yl)benzonitrile

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Reaction Steps

To a solution of 4-(1-cyclopentyl-4-oxo-4,5-dihydro-1H-pyrazolo[4,3-c]pyridin-3-yl)benzamide (32.0 mg) obtained in Example 142 in THF (10 ml) were added pyridine (0.032 mL) and trifluoroacetic anhydride (0.028 mL) at 0° C., and the mixture was stirred overnight at room temperature. Pyridine (0.032 mL) and trifluoroacetic anhydride (0.028 mL) were added thereto, and the mixture was stirred at room temperature for 2 hr. To the reaction mixture was added saturated aqueous ammonium chloride solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (methanol/ethyl acetate) to give a mixture containing the title compound and the raw material (4-(1-cyclopentyl-4-oxo-4,5-dihydro-1H-pyrazolo[4,3-c]pyridin-3-yl)benzamide. To a solution of the obtained 4-(1-cyclopentyl-4-oxo-4,5-dihydro-1H-pyrazolo[4,3-c]pyridin-3-yl)benzamide in THF were added triethylamine (0.055 mL) and trifluoroacetic anhydride (0.028 mL) at 0° C., and the mixture was stirred overnight at room temperature. To the reaction mixture was added saturated aqueous ammonium chloride solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained residue was combined with the mixture containing the title compound, and purified by silica gel column chromatography (ethyl acetate/hexane) to give the title compound (6.10 mg).

Provenance & Evidence