Dimethylformamide → 1-Ethyl-1H-indole-3-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To a 500 milliliter reaction vessel equipped with a magnetic stirrer is added 100 milliliters anhydrous dimethylformamide and 80 milliliters anhydrous ethylether. The reaction vessel is now partially immersed in an oil bath and 14.2 grams (0.098 moles) indole-3-carboxaldehyde (purified) introduced into the reaction vessel followed by the addition of 24.9 grams (0.1 moles) thallous ethoxide. The reaction mixture is then heated to a temperature in the range of about 35° - 40° C with constant stirring for a period of about 20 minutes. At the end of this period, about 15.6 grams (0.1 moles) ethyliodide is introduced into the reaction vessel and the oil bath temperature raised to about 55° C. Subsequent to the addition of the above material and prior to increase in the temperature, the reaction vessel is equipped with a reflux condenser. Heating at the above temperature is allowed to proceed for about 60 minutes. A large amount of orange/yellow precipitate is formed during this period. The reaction mixture is allowed to cool to room temperature, filtered and the filtrate poured into one liter of water. The ether layer is saved and the water layer extracted with chloroform. The chloroform extracts are combined with the ether portion and the combined solution reextracted several times with water to remove residual traces of dimethylformamide. The chloroform layer is then dried over anhydrous magnesium sulfate, filtered and flash evaporated. An oily residue which remains is crystallized from cyclohexanone. Yield: 50 - 60 percent of white platelett crystals, m. p. 103° C.

Provenance & Evidence