Hydrochloric Acid → 5-chloro-3-hydroxy-3-(2-isopropylphenyl)-1,3-dihydro-2H-indol-2-one

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Reaction Steps

Several drops of a 12 mL tetrahydrofuran solution of 8.2 g of 1-bromo-2-isopropylbenzene were added to a 5 mL tetrahydrofuran solution of 1.2 g of magnesium under a nitrogen atmosphere to initiate the reaction, after which the rest was gradually added drop-wise at a rate at which heating reflux was maintained. Upon completion of the dropping, the reaction mixture was refluxed for 0.5 hour in an oil bath, and then cooled to room temperature. A reagent prepared as above was gradually added drop-wise under ice cooling and a nitrogen atmosphere to a suspension of 3 g of 5-chloro-1H-indol-2,3-dione in 22 mL of tetrahydrofuran. Upon completion of the dropping, the temperature was raised to room temperature, and then the reaction mixture was stirred for 2 hours at that temperature. A 3N hydrochloric acid aqueous solution was poured into the reaction solution, and extraction was performed with ethyl acetate. The organic layer was washed with water and saturated brine and dried with magnesium sulfate, and the drying agent was then filtered off and the solvent was distilled off under reduced pressure. The residue was purified by column chromatography (silica gel 60, mobile phase: ethyl acetate/hexane=1/2; v/v) to obtain 4.9 g of the titled compound (pale yellow, amorphous).

Provenance & Evidence