Water → 4-Pyridin-4-yl-1,3-dihydro-indol-2-one

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Reaction Steps

Pyridinium tribromide (90% (Aldrich), 24.70 g, 69.50 mmol) was added portion-wise over 10 minutes to a suspension of 4-pyridin-4-yl-1H-indole (4.50 g, 23.17 mmol) in 2-methyl-2-propanol (135 mL), ethanol (90 mL) and acetic acid (45 mL). The mixture was stirred at room temperature for one hour and then acetic acid (180 mL) was added. After stirring for an additional hour, water (1 mL) and zinc dust (15.06 g, 232 mmol) were added and stirring was continued for another hour. Residual zinc dust was removed by filtration and washed with methanol. The filtrate was concentrated and the syrupy residue was stirred in water (500 mL) overnight. The solid that formed was filtered, washed with water to remove zinc and pyridine salts and dried under high vacuum dry to give 5.85 g (99%) of 4-pyridin-4-yl-1,3-dihydroindol-2-one as a light yellow solid.

Provenance & Evidence