Chlorosuccinimide → HCID 20351110, compound

Participants

Reaction Steps

A solution of 5-chloro-3-methylthiooxindole (1.35 g, 6.3 mmol) and N-chlorosuccinimide (950 mg, 7 mmol) in carbon tetrachloride (100 ml) was refluxed for 1 hour, cooled, and the precipitate was removed by filtration. The filtrate was concentrated to dryness, yielding crude 3,5-dichloro-3-methylthiooxindole. The residue was dissolved in 25 ml of tetrahydrofuran and added rapidly to a vigorously stirred slurry of red mercuric oxide (1.37 g, 6.3 mmol) and boron trifluoride etherate (900 mg, 6.3 mmol) in 100 ml of 20 percent aqueous tetrahydrofuran. After stirring for 3 hours, the solution was filtered through a pad of Celite and the filtrate was extracted with chloroform. The chloroform extracts were dried over anhydrous magnesium sulfate, filtered and the filtrates were concentrated to give a red solid which was chromatographed on silica gel with chloroform as the eluent. There was obtained 5-chloroisatin (850 mg, 75%), mp 248°-251° (recrystallized from ethanol).

Provenance & Evidence