1,3-Dimethyl-1,3-dihydro-2H-indole-2-thione → HCID 20351114, compound

Participants

Reaction Steps

A solution of 1-methyl-3-methylthiooxindole (1.07 g, 5.56 mmol) and N-chlorosuccinimide (800 mg, 6.0 mmol) in 75 ml of carbon tetrachloride was stirred at room temperature for 1 hour, filtered, and the filtrate was evaporated to give a residue yielding 3-chloro-1-methyl-3-methylthiooxindole. The residue was dissolved in 20 ml of tetrahydrofuran and rapidly added to a vigorously stirred slurry of red mercuric oxide (1.20 g, 5.56 mmol) and boron trifluoride etherate (790 mg, 5.56 mmol) in 75 mol of 20 percent aqueous tetrahydrofuran. After stirring at room temperature for 1 hour, the reaction mixture was filtered through a Celite pad and the filtrate was extracted with ether. Evaporation of the ether layer gave a residue which was purified by chromatography on silica gel. Elution with methylene chloride gave 1-methylisatin (550 mg, 61%), mp 131°-133°; nmr (CDCl3) π 2.23-2.60 (m, 2H, aromatic H), 2.71- 2.90 (m, 2H, aromatic H) and 6.70 (s, 3H, N--CH3).

Provenance & Evidence