3-methyl-1,3-dihydroindole-2-thione

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 3-methylthiooxindole (1.70 g, 0.0095 mol) and N-chlorosuccinimide (1.34 g, 0.01 mol) in 100 ml of carbon tetrachloride was stirred at room temperature for 1 hour, the precipitate of succinimide was removed by filtration, and the filtrate was evaporated, yielding crude 3-chloro-3-methylthiooxindole. The residue, which was thus obtained, was dissolved in a minimum of tetrahydrofuran and added to a vigorously stirred slurry of red mercuric oxide powder (2.17 g, 0.01 mol) and boron trifluoride etherate (1.43 g, 0.01 mol) in 20 percent aqueous tetrahydrofuran (70 ml). After stirring at room temperature for 1 hour, 200 ml of ether was added, the reaction mixture was filtered through a pad of Celite and the organic phase of the filtrate was separated, dried over anhydrous magnesium sulfate, filtered, and this filtrate was evaporated to give isatin (1.07 g, 78%), mp 200°-202° after recrystallization from benzene. the precipitate of succinimide was removed by filtration the filtrate was evaporated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 3-methylthiooxindole (1.70 g, 0.0095 mol) and N-chlorosuccinimide (1.34 g, 0.01 mol) in 100 ml of carbon tetrachloride was stirred at room temperature for 1 hour, the precipitate of succinimide was removed by filtration, and the filtrate was evaporated, yielding crude 3-chloro-3-methylthiooxindole. The residue, which was thus obtained, was dissolved in a minimum of tetrahydrofuran and added to a vigorously stirred slurry of red mercuric oxide powder (2.17 g, 0.01 mol) and boron trifluoride etherate (1.43 g, 0.01 mol) in 20 percent aqueous tetrahydrofuran (70 ml). After stirring at room temperature for 1 hour, 200 ml of ether was added, the reaction mixture was filtered through a pad of Celite and the organic phase of the filtrate was separated, dried over anhydrous magnesium sulfate, filtered, and this filtrate was evaporated to give isatin (1.07 g, 78%), mp 200°-202° after recrystallization from benzene. the precipitate of succinimide was removed by filtration the filtrate was evaporated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: According to the general procedure, 0.48 g of 3-methylthiooxindole and an equimolar quantity (E.Q.) of sublimed potassium t-butoxide in 200 ml of dry diethyl ether was aerated for 4 h at 0° C. and 20 h at 25° C. Acidification with 0.22 ml of conc. hydrochloric acid in 25 ml of water followed by extraction with ether, drying of the extracts over anhydrous magnesium sulfate, filtration, and evaporation of the filtrate gave an orange solid. Recrystallization from chloroform gave 0.13 g (32% yield) of pure isatin, mp 199°-200° C. Acidification with 0.22 ml of conc. hydrochloric acid in 25 ml of water followed by extraction with ether drying of the extracts over anhydrous magnesium sulfate, filtration, and evaporation of the filtrate gave an orange solid Recrystallization from chloroform