Iodine → 5-Methoxy-3-cyanomethylthioindole

Participants

Reaction Steps

To a solution of 50 g (0.34 mole) of 5-methoxyindole and 25.8 (0.34 mole) of thiourea in 1700 ml of 50% aqueous methanol was added 340 ml of KI/I2 in water over a 5 minute period and the reaction mixture was allowed to stir at room temperature for 3 hours. The reaction mixture was then evaporated in vacuo to about 1100 ml, 68 ml of 50% aqueous NaOH were added under nitrogen, the temperature brought to 85° and the mixture was stirred at 80°-90° for 40 minutes. The mixture was cooled and filtered through glass wool and under nitrogen, 21.2 ml (25.4 g; 0.34 mole) of chloroacetonitrile were added. The reaction was allowed to proceed under N2 for 18 hours after which the reaction mixture was layered over with about 800 ml of diethyl ether and the ether was separated off having dissolved a large portion of suspended solid material. The aqueous solution was extracted three times with 500 ml portions of ether which were combined with the other washings and dried over anhydrous K2CO3. The ether layer was filtered and evaporated in vacuo to 33 g of 5-methoxy-3-cyanomethylthioindole (42% yield) as a tan solid.

Provenance & Evidence