Acetic Acid → 4-(2,3-Difluoro-phenyl)-1,3-dihydro-indol-2-one

Participants

Reaction Steps

4-(2,3-Difluoro-phenyl)-1H-indole 3c (744 mg, 3.25 mmol) was dissolved in 12 mL of ethanol under stirring at room temperature, and 21 mL of tert-butanol, 6.4 mL of glacial acetic acid and pyridinium tribromide (3.12 g, 9.7 mmol) were then added successively to the solution. Upon completion of the addition, the reaction mixture was stirred for 3 hours, and 16 mL of glacial acetic acid and zinc dust (1.1 g, 16.25 mmol) were then added to the mixture. The reaction mixture was stirred for another 1 hour, filtered to remove the residue and concentrated under reduced pressure. The residue was added with 30 mL of ethyl acetate, washed successively with 10 mL of water, 10 mL of saturated sodium bicarbonate solution and 10 mL of saturated brine, dried over anhydrous sodium sulfate and filtered to remove the drying agent. The filtrate was concentrated under reduced pressure to give the title compound 4-(2,3-difluoro-phenyl)-1,3-dihydro-indol-2-one 3d (780 mg, yield 97%) as a white solid.

Provenance & Evidence